JP2007008174A - Printing apparatus, printing apparatus control program, printing apparatus control method, printing data generation apparatus, printing data generation program, and printing data generation method - Google Patents

Abstract

A novel printing apparatus, printing apparatus control program, printing apparatus control method, printing data generation apparatus, printing data generation program, and printing data generation that can eliminate banding due to a flying bend phenomenon or make it almost inconspicuous Provide a method.
An image data acquisition unit that acquires image data constituting a predetermined image from an external device, a storage device, or the like, and a color mixing ratio of an image portion corresponding to a nozzle involved in banding. A second image data generation unit 11 that generates second image data that is converted so as to avoid or reduce the image, and for printing an image of the second image data on a print medium (here, printing paper) The printing data generation unit 12 generates data and the printing unit 13 prints an image of image data on a printing medium by an inkjet method based on the printing data.
[Selection] Figure 1

Description

  The present invention relates to a printing apparatus, a printing apparatus control program, and a printing apparatus control method used for a facsimile apparatus, a copying machine, a printing apparatus for office automation equipment, and the like. ) A printing apparatus suitable for performing a so-called ink jet printing process, in which predetermined characters and images are drawn by being discharged onto the printing apparatus, a printing apparatus control program and a printing apparatus control method, and a printing data generation apparatus, The present invention relates to a print data generation program and a print data generation method.

The following describes a printing apparatus, particularly a printer that employs an inkjet method (hereinafter referred to as an “inkjet printer”).
Ink jet printers are generally inexpensive and can easily obtain high-quality color prints, and are widely used not only in offices but also in general users with the spread of personal computers and digital cameras.

  In such an ink jet printer, a moving body called a carriage or the like in which an ink cartridge and a print head are integrated is generally placed on a print medium (paper) in a direction perpendicular to the paper feed direction. By ejecting (injecting) liquid ink particles in the form of dots from the nozzles of the print head while reciprocating, predetermined characters and images are drawn on the print medium to create a desired printed matter ( In some embodiments, the ink cartridge and the print head are separated and ink is supplied to the print head via a tube or the like). The carriage is equipped with ink cartridges of four colors (black, yellow, magenta, cyan) including black (black) and a print head for each color, so that not only monochrome printing but also full-color printing combining each color is possible. (Furthermore, 6 colors, 7 colors, or 8 colors in which light cyan, light magenta, etc. are added to these colors are also put into practical use).

  In addition, in this type of ink jet printer in which printing is executed while the print head on the carriage is reciprocated in a direction perpendicular to the paper feed direction, several tens of print heads are used to cleanly print the entire page. Since it is necessary to reciprocate more than 100 times from the first time, there is a disadvantage that it takes much longer printing time than other types of printing apparatuses, for example, laser printers using electrophotographic technology such as copying machines. is there.

  On the other hand, in an inkjet printer of a type in which a long print head having the same (or long) dimension as the width of the print paper is used and a carriage is not used, it is not necessary to move the print head in the width direction of the print paper. Since printing can be performed by so-called one scanning (one pass), high-speed printing is possible as in the case of the laser printer. In addition, since a carriage for mounting the print head and a drive system for moving the print head are not required, the printer casing can be reduced in size and weight, and the quietness can be greatly improved. Yes. The former inkjet printer is generally called a “multi-pass printer”, and the latter inkjet printer is generally called a “line head printer” or a “serial printer”.

  By the way, a print head indispensable for such an ink jet printer is one in which fine nozzles having a diameter of about 10 to 70 μm are arranged in one row at a constant interval or in a plurality of rows in the printing direction. Due to manufacturing error, the ink ejection direction of some nozzles may be tilted, or the position of the nozzles may be shifted from the ideal position. A so-called “flight bend phenomenon” may occur, such as deviation. In addition, there are inks whose ink amount is greatly increased or decreased as compared with the ideal amount, as the variation is large due to the dispersion characteristics of the nozzles.

  As a result, a printing defect referred to as a so-called “banding phenomenon” may occur in a portion printed using the defective nozzle, and the print quality may be significantly reduced. In other words, when the “flight bend” phenomenon occurs, the distance between the dots ejected by the adjacent nozzles becomes non-uniform, and the portion where the distance between adjacent dots is longer than normal is indicated by “white streaks (if the printing paper is white) ) ”Occurs, and“ dark streaks ”occur in a portion where the distance between adjacent dots is shorter than normal. Even when the ink amount is not ideal, a dark streak occurs in a nozzle portion where the ink amount is large, and a white streak occurs in a portion where the ink amount decreases.

  In particular, the banding phenomenon is more likely to occur in the “line head type printer” in which the print head or print medium is fixed (one pass printing) than in the case of the “multi-pass type printer” (serial printer) as described above. (In multi-pass printers, there is a technique that makes banding inconspicuous by using the print head reciprocating many times).

Therefore, in order to prevent a kind of printing failure due to such "banding phenomenon", research and development in the so-called hardware part such as improvement of print head manufacturing technology and design improvement has been earnestly advanced. It is difficult to provide a print head in which 100% “banding phenomenon” does not occur due to manufacturing costs, technical aspects, and the like.
Therefore, in addition to the improvement in the hardware part as described above, a technology that reduces such “banding phenomenon” by using a so-called software method such as printing control as described below is used in combination. Has been.

  For example, in Patent Document 1 and Patent Document 2 shown below, in order to deal with nozzle variations and ink non-ejection, the shading correction technique is used to deal with head variations in areas where the print density is low, and printing is performed. The dark portion is substituted with another color (for example, when printing in black, cyan or magenta is used) so that banding and variations are not noticeable.

Further, in Patent Document 3 shown below, with respect to a solid image (that is, an image that is painted so that the background is not visible), the discharge amount of the adjacent nozzles in the vicinity of the non-ejection nozzle is increased, and a solid image is generated with the entire nozzle. The technique of doing is adopted.
Further, in Patent Document 4 shown below, the variation amount of each nozzle is fed back to error diffusion and processed, and the variation in the ink discharge amount of the nozzle is absorbed to avoid the banding phenomenon.
Japanese Patent Laid-Open No. 2002-19101 JP 2003-136702 A JP 2003-63043 A JP-A-5-30361

However, in the technique of reducing the banding phenomenon and variation using other colors as in the prior arts of Patent Document 1 and Patent Document 2 described above, the hue of the processed portion changes, so color photographs are taken. Not suitable for printing that requires high image quality and high quality, such as image printing.
In addition, the method of avoiding the “white streak phenomenon” by distributing the information on the non-ejection nozzles to the left and right for areas with high density is reduced when this is applied to the “flight bend phenomenon” described above. Although it is possible, there is a problem that banding still remains in a portion where the concentration is high.

In the method such as the prior art of Patent Document 3 described above, there is no problem if the printed matter is a solid image, but this method cannot be used if the printed matter is a halftone printed matter. In addition, the method of filling thin lines with other colors is fine as long as it is used very little, but in an image in which other colors occur continuously, a part of the image is similar to the former. The problem remains that the hue changes.
Further, in the method such as the conventional technique of Patent Document 4 described above, there is a problem that the process of performing appropriate feedback is complicated and difficult to solve for the problem that the dot formation content is shifted.

  Therefore, the present invention has been made paying attention to such an unsolved problem of the conventional technology, and it is possible to eliminate the degradation of image quality due to the banding phenomenon caused by the flight bending phenomenon or to make it hardly noticeable. New printing apparatus, printing apparatus control program, printing apparatus control method, printing data generation apparatus, printing data generation program, and printing capable of eliminating image quality deterioration due to defective ink ejection or making it almost inconspicuous The purpose is to provide a data generation method.

[Mode 1] In order to achieve the above object, a printing apparatus according to mode 1
A printing apparatus capable of forming dots on a medium used for printing and printing a color image to be printed on the medium by a print head having a plurality of nozzles corresponding to a plurality of colors of ink,
Image data acquisition means for acquiring first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to each color of the color image;
Nozzle information storage means for storing nozzle information capable of identifying nozzles involved in banding in the plurality of nozzles;
Second image data generating means for generating second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in banding in the first image data based on the nozzle information;
Print data generated by converting the second image data into dot formation pattern data corresponding to each color of the color image for forming a color image composed of the second image data on the medium. Printing data generation means for
Printing means for printing a color image constituted by the second image data by the print head on the medium based on the printing data;
The second image data generation means applies the abnormal nozzle to an image portion of a predetermined color printed by a nozzle corresponding to a plurality of colors including the abnormal nozzle in a color image constituted by the first image data. The pixel value of the pixel data corresponding to is changed to a value that avoids or reduces the banding, and after the change, the image portion of the predetermined color is printed so that the predetermined color falls within the same color range. The pixel value of pixel data corresponding to a nozzle having a color different from the color of ink ejected by the abnormal nozzle is changed.

  With such a configuration, the first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to the respective colors of the color image can be acquired by the image data acquisition means. It is possible to store nozzle information capable of identifying the nozzles involved in banding in the plurality of nozzles by the nozzle information storage unit, and based on the nozzle information by the second image data generation unit, It is possible to generate second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in the banding in the first image data, and the second data is generated by a print data generation unit. The image data is assigned to each color of the color image to form a color image composed of the second image data on the medium. It is possible to generate print data that is converted into corresponding dot formation pattern data, and a color constituted by the print head by the print head based on the print data. An image can be printed on the medium.

  Furthermore, the second image data generation means applies the predetermined color image portion to be printed by the nozzles corresponding to a plurality of colors including the abnormal nozzle in the color image constituted by the first image data. The pixel value of the pixel data corresponding to the abnormal nozzle is changed to a value that avoids or reduces the banding, and after the change, the predetermined color of the image portion of the predetermined color is in the same color range. It is possible to change the pixel value of pixel data corresponding to a nozzle having a color different from the color of ink ejected by the abnormal nozzle related to printing.

  Accordingly, the ink discharge amount of the nozzles involved in the banding constituting the image portion of the predetermined color is changed so as to reduce the discharge amount, for example, so as not to generate banding. By compensating for the decrease by increasing the ink discharge amount of the nozzle of another color different from the color corresponding to the abnormal nozzle, the pixels of the image portion of the predetermined color so that the predetermined color falls within the same color range. Since the values can be reconfigured, the print result can be in a state where banding does not occur in the print result, or in the state where banding is not conspicuous in the print result, and in addition to maintaining color information before the change, banding Since only the nozzles (abnormal nozzles) involved in the ink change the ink discharge amount, the image of the image data can be printed with the image quality that does not impair the naturalness. The effect is obtained that can be reproduced in.

  Here, the dot refers to one region formed by ink ejected from one or a plurality of nozzles landing on a print medium. Further, “dots” are not “zero” in area, and of course have a certain size (area), and there are a plurality of types for each size. However, dots formed by ejecting ink are not always perfect circles. For example, when dots are formed in a shape other than a perfect circle such as an ellipse, the average diameter is treated as the dot diameter, or the area equal to the area of the dots formed by ejecting a certain amount of ink is used. In some cases, a perfect circle equivalent dot is assumed and the diameter of the equivalent dot is treated as the dot diameter. In addition, for example, a method for hitting dots having different densities includes a method of hitting dots having the same dot size and different densities, a method of hitting dots having the same density and different sizes, and ejection of ink having the same density. It is possible to consider a method in which the amount of dots is different and the density is varied by overstrike. In addition, when one ink droplet ejected from one nozzle is separated and landed, it is considered as one dot, but two nozzles or two or more formed from one nozzle around the time. If two dots are stuck, it is assumed that two dots are formed. Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

  The image data acquisition unit acquires image data input from an optical print result reading unit such as a scanner unit, or passively receives image data stored in an external device via a network such as a LAN or WAN. Storage device of a printing apparatus that acquires the image data from a recording medium such as a CD-ROM or DVD-ROM through a drive device such as a CD drive or DVD drive of the printing apparatus The image data stored in is acquired. That is, the acquisition includes at least input, acquisition, reception, and reading. Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

  In addition, the “nozzle information storage unit” stores nozzle information at any time and at any time, and may store nozzle information in advance or store nozzle information in advance. Alternatively, the nozzle information may be stored by an external input or the like during operation of the printing apparatus. For example, before the printing apparatus is sold as a product at the time of factory shipment, the dot formation of each nozzle constituting the print head is made from the print result by the print head using an optical print result reading means such as a scanner means. Inspect the amount of misalignment, ink discharge status, etc., and store the inspection results in advance, or when using the printing device, the amount of misalignment of the dot formation position of each nozzle that constitutes the print head when the printer is used Any timing may be used as long as the nozzle information can be stored when the product is used. In addition, in order to cope with the case where the characteristics of the print head change after use of the printing apparatus, the print result by the print head is used regularly or at a predetermined time using an optical print result reading means such as a scanner means. The nozzle information can be updated, for example, by checking the print position deviation amount of each print head and the ink discharge state of each nozzle and storing the result of the inspection together with the data at the time of shipment from the factory or overwriting the data. You may do it. (Forms relating to “printing device control program”, “printing device control method”, “printing data generation device”, “printing data generation program”, “printing data generation method” As well as the description of the form relating to the “recording medium on which the program is recorded” and the column of the best mode for carrying out the invention.

  In addition, the “banding” is caused by a so-called “flying curve phenomenon” caused by a nozzle whose dot formation position is deviated from the ideal formation position, and “dark streaks” are simultaneously generated along with “white streaks” in the print result. Due to printing failure and ink ejection failure such as nozzle non-ejection and nozzle ejection amount more or less than normal, printing results that cause “white streaks” or “dark streaks” in the printing result It shall be said. Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

  In addition, as described above, the “flight bend phenomenon” is different from the simple non-ejection phenomenon of some nozzles, as described above, while ink is ejected, but the ejection direction of some of the nozzles is inclined and the dots are ideal. This is a phenomenon that is formed out of position. Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

  In addition, the above-mentioned “white streaks” continuously cause a phenomenon in which the distance between adjacent dots becomes wider than a predetermined distance due to the “flying curve phenomenon”, and the color of the background of the print medium becomes noticeable in a streak shape. The above-mentioned “dark streaks” are also the same as the “flying curve phenomenon”, in which the phenomenon in which the distance between adjacent dots becomes shorter than a predetermined distance continuously occurs, and the background of the print medium The color disappears, or the distance between dots becomes shorter, which makes it appear darker. Furthermore, some of the dots that are separated from each other overlap normal dots, and the overlapped part is conspicuous in dark stripes. The part (area) that is In addition, white streaks may occur due to nozzles with a small amount of ink, while dark streaks may occur due to nozzles with a large amount of ink. Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

  The “nozzles involved in banding (abnormal nozzles)” are, for example, nozzles (or ink ejection amounts that cause a “flight bend phenomenon” because the dot formation position is deviated from the ideal formation position). In the case where the above-mentioned “white streaks” are generated, for example, the distance between the nozzle where the dot formation position is shifted and the shifted dot is normal. In the case of the above-mentioned “dark streaks”, the nozzles where the dot formation position has shifted due to the “flying curve phenomenon” and the shifts thereof are included. Even if the distance is shorter than the normal case, or it includes a nozzle that forms a normal dot partly or entirely overlapping There. Note that the present invention is not limited to this example, and the range in the vicinity may be further expanded, such as three nozzles on both sides of the corresponding nozzle. Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

  The “pixel data corresponding to an abnormal nozzle” is pixel data corresponding to a dot formed by an abnormal nozzle or pixel data corresponding to a dot formed by an abnormal nozzle and its surrounding nozzles. Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

The “printing data” refers to multi-valued image data (for example, M value (M ≧ 3)) converted to N-value using an error diffusion method or the like according to the type of nozzle formation dot size ( M> N ≧ 2), and information on the presence / absence of dots (forming / not forming dots with nozzles) for each pixel value for each color of the image data, and dots when forming This information is composed of information necessary for forming dots by nozzles such as information on the size (for example, one of three types of large, medium and small). Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description regarding the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.
The “same color range” is a range that includes the target predetermined color itself, and further includes a color that can be visually perceived as the predetermined color even if it is not the predetermined color itself.

[Mode 2] Further, the printing apparatus of mode 2 is the printing apparatus of mode 1,
The second image data generation means changes the pixel value of the pixel data corresponding to the abnormal nozzle to a value that reduces the ink discharge amount of the abnormal nozzle from the discharge amount before the change, and the image portion of the predetermined color The pixel value of the pixel data corresponding to the nozzle of the other color different from the color of the abnormal nozzle related to the printing is decreased at the abnormal nozzle from the ejection amount before changing the ink discharge amount of the nozzle of the other color The second image data in which the predetermined color falls within the same color range is generated by changing the ink discharge amount to a value that compensates.

  With such a configuration, it is possible to reduce the ink discharge amount of the color involved in banding so that the banding does not occur in the print result or the banding is not noticeable in the print result. Since the change in color of the predetermined color due to the decrease is compensated for by other colors, the effect that the color change of the predetermined color can be suppressed to the same color range is obtained.

[Mode 3] Furthermore, the printing apparatus of mode 3 is the printing apparatus of mode 1 or 2,
The same color range is a range in which the color difference ΔE between the image part before the pixel value is changed and the image part after the pixel value is changed is “0 ≦ ΔE ≦ 0.7” in the Lab color space. It is characterized by that.
With such a configuration, it is possible to obtain an effect that the change in the color of the predetermined color can be more reliably suppressed to a color range that can be visually perceived as the same color.

  Here, the “Lab color space” is a color space recommended by the CIE (Commission Internationale d'Eclairage) in 1976 and is based on the XYZ color system. It is called b * color system. The L * a * b * color system is representative of so-called UCS (Uniform Color Space), and is referred to as “uniform color space” in the Japanese translation. That is, the uniform color space is a color space in which distances (psychological distance feeling) between colors that appear to be the same color difference are equalized psychologically (when the colors are viewed). Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

[Form 4] Furthermore, the printing apparatus of form 4 is the printing apparatus of any one of forms 1 to 3,
The other color different from the color of the ink ejected from the abnormal nozzle is a color different from the color of the ink ejected from the abnormal nozzle.
In such a configuration, the color balance is changed by changing the ink discharge amount of another color different from the color related to banding, for example, the ink discharge amount of the color related to banding. Since the decrease can be compensated for, an effect that the decrease in the ink ejection amount can be compensated without causing a change in hue or with a minimum change in color can be obtained.

  Here, the “different color” refers to a color different from the color of the ink ejected by the abnormal nozzle. Specifically, for example, between cyan, magenta, yellow, black, blue, red, and green, each color is a different color. Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

[Mode 5] Furthermore, the printing apparatus according to mode 5 is the printing apparatus according to any one of modes 1 to 3,
The other color different from the color of the ink ejected by the abnormal nozzle is a color of the same system as the color of the ink ejected by the abnormal nozzle.
With such a configuration, for example, when a nozzle corresponding to a highly saturated color ink is involved in banding, for example, a decrease in the ink discharge amount of the color corresponding to the nozzle is reduced to the same color. This can be compensated by changing the ink discharge amount of the low-saturated color, so that the influence of other colors can be suppressed and the occurrence of banding can be avoided while minimizing the problem of color change. The effect that it can reduce is acquired.

  Here, the “same color” refers to ink colors having the same color but different densities (saturations). For example, cyan and light cyan, magenta and light magenta, and black and gray are the same color. Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

[Mode 6] Furthermore, the printing apparatus of mode 6 is the printing apparatus of any one of modes 1 to 3,
Other colors different from the color of the ink ejected by the abnormal nozzle include both the same color and the different color of the ink ejected by the abnormal nozzle.
With such a configuration, the color balance is changed by changing the ink discharge amount of the same color and another color according to the color of the ink corresponding to the nozzle involved in the banding. As a result, it is possible to compensate for the decrease in the ink amount of the color involved in banding. The effect that it can avoid or reduce is acquired. In addition, it is possible to select a more suitable change method for each area to be processed, and it is possible to deal with more areas.

[Mode 7] Further, the printing apparatus according to mode 7 is the printing apparatus according to any one of modes 1 to 6,
The second image data generation means determines a change value of a pixel value corresponding to the abnormal nozzle based on a color corresponding to the abnormal nozzle.
With such a configuration, for example, for a relatively high lightness color such as yellow, banding does not stand out even when a considerable amount of ink is applied, but for a relatively low lightness color such as cyan or magenta, Banding becomes noticeable when a relatively small amount of ink is applied compared to a color with relatively high lightness. Therefore, the change amount of the ink discharge amount is determined (controlled) according to the lightness of the color involved in banding. ), It is possible to avoid or reduce banding with the minimum necessary change amount.

[Embodiment 8] Furthermore, the printing apparatus according to Embodiment 8 is the printing apparatus according to any one of Embodiments 1 to 7,
The printing data generation unit is configured to generate pixel data for pixel data having a pixel value with an ink ejection amount equal to or less than a predetermined amount among pixel data corresponding to nozzles involved in banding in the second image data. Printing data in which dots are not formed on a part or all of the print data is generated.

  With such a configuration, it is generally said that the same function can be achieved for a color whose ink discharge amount can be ¼ or less of the dischargeable limit amount even if the resolution of that portion is halved. When the ink discharge amount of a nozzle involved in banding can be reduced to ¼ or less, the nozzle is not used for a part of the corresponding pixel data (dots are not formed). By generating print data, it is possible to avoid or reduce banding without causing image quality degradation.

  In addition, when there is a nozzle that ejects ink of the same color as the color ink corresponding to the nozzle involved in banding, the nozzle involved in banding is not used for all of the corresponding pixel data, This unused portion can be compensated for by nozzles corresponding to similar colors, so that the target color can be reproduced without causing problems such as color change, and banding can be avoided or avoided. The effect that it can reduce is acquired.

  Here, the “ink discharge amount” is an amount indicating how many dots can be formed with respect to a predetermined area in a medium used for printing. Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

  In addition, the above “predetermined amount or less” means that the number of dots formed with respect to a predetermined area on the medium used for printing is, for example, 1/4 (25%) or less, with the maximum number of dots formed being 100%. Or it is the amount of ink (number of dots) that is ½ (50%) or less. Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

  In addition, the above “printing data in which dots are not formed” means that, for some or all of the pixel data, the dots formed by the abnormal nozzle for this pixel data are not used (not formed) at all. Is the printing data. Hereinafter, a form relating to “printing apparatus control program”, a form relating to “printing apparatus control method”, a form relating to “printing data generation apparatus”, a form relating to “printing data generation program”, a form relating to “printing data generation method”, In addition, the same applies to the description relating to the “recording medium on which the program is recorded”, the best mode for carrying out the invention, and the like.

[Mode 9] Further, the printing apparatus of mode 9 is the printing apparatus of any one of modes 1 to 8,
The print head is a print head in which the nozzles are continuously arranged over a wider range than the mounting area of the print medium, and can be printed by one scan.
With such a configuration, as described above, “white streaks” and “dark streaks” due to banding that are particularly likely to occur when using a line head type print head that finishes printing in one pass is inconspicuous. Thus, it is possible to generate printing data that is effective for this.

[Mode 10] Furthermore, the printing apparatus according to mode 10 is the printing apparatus according to any one of modes 1 to 8,
The print head is a print head that performs printing while reciprocating in a direction orthogonal to a paper feeding direction of the print medium.
The banding described above is noticeable in the case of a line head type print head, but also occurs in the case of a multi-pass type print head. Therefore, if the printing method according to any one of Embodiments 1 to 8 is applied to a multi-pass type print head, “white streaks” and “dark streaks” due to banding generated in the multi-pass type print head are conspicuous. It is possible to generate printing data that can be effectively eliminated.
In the case of a multi-pass type print head, it is possible to avoid or reduce the banding as described above by taking measures such as repeating the scan of the print head. If any one of the printing apparatuses is applied, it is not necessary to scan the same portion over and over again, so that higher-speed printing can be realized.

[Mode 11] On the other hand, in order to achieve the above object, a printing apparatus control program according to mode 11
Used to control a printing apparatus that prints a color image to be printed on a medium by a print head that can form dots on the medium used for printing and has a plurality of nozzles corresponding to inks of a plurality of colors. A printing device control program,
An image data acquisition step of acquiring first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to each color of the color image;
Second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in banding in the first image data based on nozzle information that can identify nozzles involved in banding among the plurality of nozzles. A second image data generation step for generating
Print data generated by converting the second image data into dot formation pattern data corresponding to each color of the color image for forming a color image composed of the second image data on the medium. A data generation step for printing,
A program used for causing a computer to execute a process including a printing step of printing a color image constituted by the second image data on the medium by the print head based on the printing data;
In the second image data generation step, the abnormal image portion of the predetermined color that is printed by the nozzles corresponding to a plurality of colors including the abnormal nozzles in the color image constituted by the first image data. The pixel value of the pixel data corresponding to the nozzle is changed to a value that avoids or reduces the banding, and after the change, the image portion of the predetermined color is printed so that the predetermined color is in the same color range. The pixel value of pixel data corresponding to a nozzle having a color different from the color of ink ejected by the abnormal nozzle is changed.

With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operations and effects as those of the printing apparatus of mode 1 can be obtained.
Also, most printing devices on the market such as inkjet printers are equipped with a computer system consisting of a central processing unit (CPU), a storage device (RAM, ROM), an input / output device, and the like. Since each means can be realized by software, it can be realized more economically and easily than a case where dedicated means is created to realize each means.
Furthermore, it is possible to easily upgrade the version by modifying or improving the function by rewriting a part of the program.

[Mode 12] Furthermore, the printing apparatus control program according to mode 12 is the same as the printing apparatus control program according to mode 11.
In the second image data generation step, the pixel value of the pixel data corresponding to the abnormal nozzle is changed to a value that reduces the ink discharge amount of the abnormal nozzle from the discharge amount before the change, and the image of the predetermined color The pixel value of the pixel data corresponding to the nozzle of another color different from the color of the abnormal nozzle related to the printing of the portion is changed from the discharge amount before changing the ink discharge amount of the nozzle of the other color to the abnormal nozzle. The second image data in which the predetermined color falls within the same color range is generated by changing to a value that compensates for the reduced ink discharge amount.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operation and effect as those of the printing apparatus according to mode 2 can be obtained.

[Mode 13] Furthermore, the printing apparatus control program according to mode 13 is the printing apparatus control program according to mode 11 or 12,
The same color range is a range in which the color difference ΔE between the image part before the pixel value is changed and the image part after the pixel value is changed is “0 ≦ ΔE ≦ 0.7” in the Lab color space. It is characterized by that.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operation and effect as those of the printing apparatus according to mode 3 can be obtained.

[Form 14] Furthermore, the printing apparatus control program according to form 14 is the printing apparatus control program according to any one of forms 11 to 13,
The other color different from the color of the ink ejected from the abnormal nozzle is a color different from the color of the ink ejected from the abnormal nozzle.
With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operation and effect as those of the printing apparatus of mode 4 can be obtained.

[Mode 15] Further, the printing apparatus control program according to mode 15 is the printing apparatus control program according to any one of modes 11 to 13,
The other color different from the color of the ink ejected by the abnormal nozzle is a color of the same system as the color of the ink ejected by the abnormal nozzle.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operations and effects as those of the printing apparatus of mode 5 are obtained.

[Mode 16] Further, the printing device control program according to mode 16 is the printing device control program according to any one of modes 11 to 13,
Other colors different from the color of the ink ejected by the abnormal nozzle include both the same color and the different color of the ink ejected by the abnormal nozzle.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operation and effect as those of the printing apparatus of mode 6 can be obtained.

[Mode 17] Further, the printing device control program according to mode 17 is the printing device control program according to any one of modes 11 to 16,
In the second image data generation step, a change value of a pixel value corresponding to the abnormal nozzle is determined based on a color corresponding to the abnormal nozzle.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operations and effects as those of the printing apparatus according to mode 7 can be obtained.

[Mode 18] Further, the printing apparatus control program according to mode 18 is the printing apparatus control program according to any one of modes 11 to 17,
In the printing data generation step, among pixel data corresponding to nozzles involved in banding in the second image data, pixel data having a pixel value with an ink ejection amount equal to or less than a predetermined amount Printing data in which dots are not formed for part or all of the data is generated.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operation and effect as those of the printing apparatus according to mode 8 can be obtained.

[Mode 19] On the other hand, in order to achieve the above object, a computer-readable recording medium storing the printing apparatus control program according to mode 19 is provided.
The printing apparatus control program according to any one of Form 11 to Form 18 is recorded.
As a result, the same operation and effect as the printing apparatus control program of any one of the eleventh to eighteenth aspects can be obtained, and the printing program can be easily obtained via a recording medium such as a CD-ROM, DVD-ROM, or MO. It is possible to give and receive.

[Mode 20] On the other hand, in order to achieve the above object, a printing apparatus control method according to mode 20 includes:
Used to control a printing apparatus that prints a color image to be printed on a medium by a print head that can form dots on the medium used for printing and has a plurality of nozzles corresponding to inks of a plurality of colors. A printing apparatus control method comprising:
An image data acquisition step of acquiring first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to each color of the color image;
Second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in banding in the first image data based on nozzle information that can identify nozzles involved in banding among the plurality of nozzles. A second image data generation step for generating
Print data generated by converting the second image data into dot formation pattern data corresponding to each color of the color image for forming a color image composed of the second image data on the medium. A data generation step for printing,
A program used for causing a computer to execute a process including a printing step of printing a color image constituted by the second image data on the medium by the print head based on the printing data;
In the second image data generation step, the abnormal image portion of the predetermined color that is printed by the nozzles corresponding to a plurality of colors including the abnormal nozzles in the color image constituted by the first image data. The pixel value of the pixel data corresponding to the nozzle is changed to a value that avoids or reduces the banding, and after the change, the image portion of the predetermined color is printed so that the predetermined color is in the same color range. The pixel value of pixel data corresponding to a nozzle having a color different from the color of ink ejected by the abnormal nozzle is changed.

More specifically, in the image data acquisition step, for example, a program stored in a storage medium such as a ROM is loaded into the RAM, and the loaded program is executed by the CPU, for example, an input device such as a scanner, A storage device such as an HDD, an input / output I / F, and the like cooperate to implement processing. In the second image data generation step, a program stored in a storage medium such as a ROM is loaded into the RAM, the loaded program is executed by the CPU, and various data such as nozzle information stored in the storage device is used. This is realized by performing the process. In the print data generation step, a program stored in a storage medium such as a ROM is loaded into the RAM, the loaded program is executed by the CPU, and various data such as second image data stored in the storage device is stored. Realized by making full use of processing. In the printing step, a program stored in a storage medium such as a ROM is loaded into the RAM, and the loaded program is executed by the CPU so that an output composed of a drive mechanism such as a print head or a paper feed mechanism is output. The processing is realized by inputting printing data and various control signals stored in the storage device to the apparatus and controlling the output device (printing means).
As a result, the same effect as that of the printing apparatus of aspect 1 can be obtained.

[Form 21] Furthermore, the printing apparatus control method of aspect 21 is the same as the printing apparatus control method of aspect 20.
In the second image data generation step, the pixel value of the pixel data corresponding to the abnormal nozzle is changed to a value that reduces the ink discharge amount of the abnormal nozzle from the discharge amount before the change, and the image of the predetermined color The pixel value of the pixel data corresponding to the nozzle of another color different from the color of the abnormal nozzle related to the printing of the portion is changed from the discharge amount before changing the ink discharge amount of the nozzle of the other color to the abnormal nozzle. The second image data in which the predetermined color falls within the same color range is generated by changing to a value that compensates for the reduced ink discharge amount.
As a result, the same effect as that of the printing apparatus of aspect 2 can be obtained.

[Mode 22] Further, the printing device control method of mode 22 is the printing device control method of mode 20 or 21,
The same color range is a range in which the color difference ΔE between the image part before the pixel value is changed and the image part after the pixel value is changed is “0 ≦ ΔE ≦ 0.7” in the Lab color space. It is characterized by that.
As a result, the same effect as that of the printing apparatus according to mode 3 can be obtained.

[Form 23] Furthermore, the printing apparatus control method of form 23 is the printing apparatus control method of any one of forms 20 to 22,
The other color different from the color of the ink ejected from the abnormal nozzle is a color different from the color of the ink ejected from the abnormal nozzle.
As a result, the same effect as that of the printing apparatus of aspect 4 is obtained.

[Mode 24] Further, the printing apparatus control method according to mode 24 is the printing apparatus control method according to any one of modes 20 to 22,
The other color different from the color of the ink ejected by the abnormal nozzle is a color of the same system as the color of the ink ejected by the abnormal nozzle.
As a result, the same effect as that of the printing apparatus of mode 5 can be obtained.

[Mode 25] Furthermore, the printing apparatus control method according to mode 25 is the printing apparatus control method according to any one of modes 20 to 22,
Other colors different from the color of the ink ejected by the abnormal nozzle include both the same color and the different color of the ink ejected by the abnormal nozzle.
Thereby, the same effect as that of the printing apparatus of mode 6 can be obtained.

[Mode 26] Further, the printing device control method of mode 26 is the printing device control method of any one of modes 20 to 25,
In the second image data generation step, a change value of a pixel value corresponding to the abnormal nozzle is determined based on a color corresponding to the abnormal nozzle.
As a result, the same effect as that of the printing apparatus of mode 7 can be obtained.

[Mode 27] Furthermore, the printing apparatus control method according to mode 27 is the printing apparatus control method according to any one of modes 20 to 26.
In the printing data generation step, among pixel data corresponding to nozzles involved in banding in the second image data, pixel data having a pixel value with an ink ejection amount equal to or less than a predetermined amount Printing data in which dots are not formed for part or all of the data is generated.
As a result, the same effect as that of the printing apparatus of aspect 8 is obtained.

[Mode 28] On the other hand, in order to achieve the above object, the print data generation apparatus according to mode 28
Printing data used in a printing apparatus that prints a color image to be printed on the medium by a print head that can form dots on a medium used for printing and has a plurality of nozzles corresponding to a plurality of colors of ink. A print data generation device for generating
Image data acquisition means for acquiring first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to each color of the color image;
Nozzle information storage means for storing nozzle information capable of identifying nozzles involved in banding in the plurality of nozzles;
Second image data generating means for generating second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in banding in the first image data based on the nozzle information;
Print data generated by converting the second image data into dot formation pattern data corresponding to each color of the color image for forming a color image constituted by the second image data on the medium. Printing data generation means for
The second image data generation unit applies an abnormal nozzle to an image portion of a predetermined color printed by a nozzle corresponding to a plurality of colors including the abnormal nozzle in a color image constituted by the first image data. The pixel value of the corresponding pixel data is changed to a value that avoids or reduces the banding, and after the change, the image portion of the predetermined color is printed so that the predetermined color is in the same color range. A pixel value of pixel data corresponding to a nozzle having a color different from the color of ink ejected by the abnormal nozzle is changed.

That is, this embodiment does not include printing means for actually executing printing as in the printing apparatus, but generates printing data according to the characteristics of the print head based on the original M-value image data. It is what you do.
Accordingly, it is possible to obtain the same operations and effects as the printing apparatus of form 1, and for example, it is possible to execute print processing by the printing apparatus simply by sending the printing data generated in this form to the printing apparatus. Therefore, with such a configuration, an existing inkjet printing apparatus can be used as it is without preparing a dedicated printing apparatus.
In addition, since a general-purpose information processing device such as a personal computer can be used, an existing printing system including a print instruction device such as a personal computer and an inkjet printer can be used as it is.

[Mode 29] Furthermore, the printing data generation device of mode 29 is the printing data generation device of mode 28,
The second image data generation means changes the pixel value of the pixel data corresponding to the abnormal nozzle to a value that reduces the ink discharge amount of the abnormal nozzle from the discharge amount before the change, and the image portion of the predetermined color The pixel value of the pixel data corresponding to the nozzle of the other color different from the color of the abnormal nozzle related to the printing is decreased at the abnormal nozzle from the ejection amount before changing the ink discharge amount of the nozzle of the other color The second image data in which the predetermined color falls within the same color range is generated by changing the ink discharge amount to a value that compensates.
As a result, the same operation and effect as those of the printing apparatus of mode 2 can be obtained.

[Mode 30] Furthermore, the printing data generation device according to mode 30 is the printing data generation device according to mode 28 or 29,
The same color range is a range in which the color difference ΔE between the image part before the pixel value is changed and the image part after the pixel value is changed is “0 ≦ ΔE ≦ 0.7” in the Lab color space. It is characterized by that.
As a result, the same operations and effects as those of the printing apparatus of aspect 3 are obtained.

[Mode 31] Furthermore, the printing data generation device according to mode 31 is the printing data generation device according to any one of modes 28 to 30,
The other color different from the color of the ink ejected from the abnormal nozzle is a color different from the color of the ink ejected from the abnormal nozzle.
Thereby, the same operation and effect as those of the printing apparatus of aspect 4 can be obtained.

[Mode 32] Furthermore, the printing data generation device according to mode 32 is the printing data generation device according to any one of modes 28 to 30,
The other color different from the color of the ink ejected by the abnormal nozzle is a color of the same system as the color of the ink ejected by the abnormal nozzle.
As a result, the same operations and effects as those of the printing apparatus of aspect 5 are obtained.

[Mode 33] Furthermore, the printing data generation device according to mode 33 is the printing data generation device according to any one of modes 28 to 30,
Other colors different from the color of the ink ejected by the abnormal nozzle include both the same color and the different color of the ink ejected by the abnormal nozzle.
Thereby, the same operation and effect as those of the printing apparatus of mode 6 can be obtained.

[Form 34] Furthermore, the print data generation device according to form 34 is the print data generation device according to any one of forms 28 to 33.
The second image data generation means determines a change value of a pixel value corresponding to the abnormal nozzle based on a color corresponding to the abnormal nozzle.
As a result, the same operations and effects as those of the printing apparatus of aspect 7 are obtained.

[Mode 35] Furthermore, the printing data generation device according to mode 35 is the printing data generation device according to any one of modes 28 to 34.
The printing data generation unit is configured to generate pixel data for pixel data having a pixel value with an ink ejection amount equal to or less than a predetermined amount among pixel data corresponding to nozzles involved in banding in the second image data. Printing data in which dots are not formed on a part or all of the print data is generated.
Thereby, the same operation and effect as those of the printing apparatus of aspect 8 can be obtained.

[Mode 36] On the other hand, in order to achieve the above object, a print data generation program according to mode 36
Printing data used in a printing apparatus that prints a color image to be printed on the medium by a print head that can form dots on a medium used for printing and has a plurality of nozzles corresponding to a plurality of colors of ink. A print data generation program used to generate
An image data acquisition step of acquiring first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to each color of the color image;
Second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in banding in the first image data based on nozzle information that can identify nozzles involved in banding among the plurality of nozzles. A second image data generation step for generating
Print data generated by converting the second image data into dot formation pattern data corresponding to each color of the color image for forming a color image composed of the second image data on the medium. Including a program used to cause a computer to execute a process consisting of a print data generation step
In the second image data generation step, the abnormal nozzle for an image portion of a predetermined color printed by nozzles corresponding to a plurality of colors including the abnormal nozzle in the color image constituted by the first image data. The pixel value of the pixel data corresponding to is changed to a value that avoids or reduces the banding, and after the change, the image portion of the predetermined color is printed so that the predetermined color falls within the same color range. The pixel value of pixel data corresponding to a nozzle having a color different from the color of ink ejected by the abnormal nozzle is changed.

  With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operations and effects as those of the print data generating apparatus of form 28 are obtained.

[Mode 37] Further, the print data generation program of mode 37 is the same as the print data generation program of mode 36,
In the second image data generation step, the pixel value of the pixel data corresponding to the abnormal nozzle is changed to a value that reduces the ink discharge amount of the abnormal nozzle from the discharge amount before the change, and the image of the predetermined color The pixel value of the pixel data corresponding to the nozzle of another color different from the color of the abnormal nozzle related to the printing of the portion is changed from the discharge amount before changing the ink discharge amount of the nozzle of the other color to the abnormal nozzle. The second image data in which the predetermined color falls within the same color range is generated by changing to a value that compensates for the reduced ink discharge amount.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operations and effects as those of the printing data generation apparatus according to mode 29 are obtained.

[Mode 38] Furthermore, the printing data generation program of mode 38 is the printing data generation program of mode 36 or 37,
The same color range is a range in which the color difference ΔE between the image part before the pixel value is changed and the image part after the pixel value is changed is “0 ≦ ΔE ≦ 0.7” in the Lab color space. It is characterized by that.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operations and effects as those of the printing data generation apparatus according to form 30 are obtained.

[Mode 39] Furthermore, the print data generation program of mode 39 is the print data generation program of any one of modes 36 to 38.
The other color different from the color of the ink ejected from the abnormal nozzle is a color different from the color of the ink ejected from the abnormal nozzle.
With such a configuration, when the program is read by the computer and the computer executes processing according to the read program, the same operations and effects as those of the printing data generation apparatus according to mode 31 are obtained.

[Form 40] Furthermore, the print data generation program according to form 40 is the print data generation program according to any one of forms 36 to 38.
The other color different from the color of the ink ejected by the abnormal nozzle is a color of the same system as the color of the ink ejected by the abnormal nozzle.
With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operations and effects as those of the printing data generation apparatus of mode 32 are obtained.

[Form 41] Furthermore, the print data generation program of form 41 is the print data generation program of any one of forms 36 to 38.
Other colors different from the color of the ink ejected by the abnormal nozzle include both the same color and the different color of the ink ejected by the abnormal nozzle.
With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operations and effects as those of the printing data generation apparatus of form 33 are obtained.

[Form 42] Furthermore, the print data generation program of form 42 is the print data generation program of any one of forms 36 to 41.
In the second image data generation step, a change value of a pixel value corresponding to the abnormal nozzle is determined based on a color corresponding to the abnormal nozzle.
With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operation and effect as those of the printing data generation apparatus in form 34 can be obtained.

[Form 43] Furthermore, the print data generation program of form 43 is the print data generation program of any one of forms 36 to 42.
In the printing data generation step, among pixel data corresponding to nozzles involved in banding in the second image data, pixel data having a pixel value with an ink ejection amount equal to or less than a predetermined amount Printing data in which dots are not formed for part or all of the data is generated.
With such a configuration, when the program is read by the computer and the computer executes processing in accordance with the read program, the same operations and effects as those of the printing data generation apparatus of form 35 are obtained.

[Form 44] On the other hand, in order to achieve the above object, a computer-readable recording medium on which the print data generation program of form 44 is recorded is provided.
The printing data generation program according to any one of forms 36 to 43 is recorded.
As a result, the same operation and effect as the print data generation program of any one of forms 36 to 43 can be obtained, and the above-described operation can be performed via a recording medium such as a CD-ROM, DVD-ROM, or FD (flexible disk). It is possible to easily exchange printing programs.

[Mode 45] On the other hand, in order to achieve the above object, a printing data generation method according to mode 45 includes:
Printing data used in a printing apparatus that prints a color image to be printed on the medium by a print head that can form dots on a medium used for printing and has a plurality of nozzles corresponding to a plurality of colors of ink. A print data generation method used to generate
An image data acquisition step of acquiring first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to each color of the color image;
Second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in banding in the first image data based on nozzle information that can identify nozzles involved in banding among the plurality of nozzles. A second image data generation step for generating
Print data generated by converting the second image data into dot formation pattern data corresponding to each color of the color image for forming a color image constituted by the second image data on the medium. Printing data generation step to
In the second image data generation step, the abnormal nozzle for an image portion of a predetermined color printed by nozzles corresponding to a plurality of colors including the abnormal nozzle in the color image constituted by the first image data. The pixel value of the pixel data corresponding to is changed to a value that avoids or reduces the banding, and after the change, the image portion of the predetermined color is printed so that the predetermined color falls within the same color range. The pixel value of pixel data corresponding to a nozzle having a color different from the color of ink ejected by the abnormal nozzle is changed.

More specifically, in the image data acquisition step, for example, a program stored in a storage medium such as a ROM is loaded into the RAM, and the loaded program is executed by the CPU, for example, an input device such as a scanner, A storage device such as an HDD, an input / output I / F, and the like cooperate to implement processing. In the second image data generation step, a program stored in a storage medium such as a ROM is loaded into the RAM, the loaded program is executed by the CPU, and various data such as nozzle information stored in the storage device is used. This is realized by performing the process. In the print data generation step, a program stored in a storage medium such as a ROM is loaded into the RAM, the loaded program is executed by the CPU, and various data such as second image data stored in the storage device is stored. Realized by making full use of processing.
Thus, the same operation and effect as those of the form 28 printing data generation apparatus can be obtained.

[Form 46] Furthermore, the print data generation method of form 46 is the same as the print data generation method of form 45,
In the second image data generation step, the pixel value of the pixel data corresponding to the abnormal nozzle is changed to a value that reduces the ink discharge amount of the abnormal nozzle from the discharge amount before the change, and the image of the predetermined color The pixel value of the pixel data corresponding to the nozzle of another color different from the color of the abnormal nozzle related to the printing of the portion is changed from the discharge amount before changing the ink discharge amount of the nozzle of the other color to the abnormal nozzle. The second image data in which the predetermined color falls within the same color range is generated by changing to a value that compensates for the reduced ink discharge amount.
As a result, the same operation and effect as those of the printing data generation apparatus of form 29 are obtained.

[Form 47] Furthermore, the print data generation method of form 47 is the same as the print data generation method of form 45 or 46,
The same color range is a range in which the color difference ΔE between the image part before the pixel value is changed and the image part after the pixel value is changed is “0 ≦ ΔE ≦ 0.7” in the Lab color space. It is characterized by that.
As a result, the same operation and effect as those of the printing data generation apparatus of form 30 can be obtained.

[Form 48] Furthermore, the print data generation method of form 48 is the print data generation method of any one of forms 45 to 47,
The other color different from the color of the ink ejected from the abnormal nozzle is a color different from the color of the ink ejected from the abnormal nozzle.
Thereby, the same operation and effect as those of the printing data generation apparatus of form 31 are obtained.

[Form 49] Furthermore, the print data generation method of form 49 is the print data generation method of any one of forms 45 to 47,
The other color different from the color of the ink ejected by the abnormal nozzle is a color of the same system as the color of the ink ejected by the abnormal nozzle.
As a result, the same operation and effect as those of the printing data generation apparatus of form 32 are obtained.

[Form 50] Furthermore, the print data generation method according to form 50 is the print data generation method according to any one of forms 45 to 47.
Other colors different from the color of the ink ejected by the abnormal nozzle include both the same color and the different color of the ink ejected by the abnormal nozzle.
As a result, the same operations and effects as those of the printing data generation apparatus of form 33 are obtained.

[Form 51] Further, the print data generation method of form 51 is the print data generation method of any one of forms 45 to 50,
In the second image data generation step, a change value of a pixel value corresponding to the abnormal nozzle is determined based on a color corresponding to the abnormal nozzle.
Thereby, the same operation and effect as those of the printing data generation apparatus of form 34 can be obtained.

[Form 52] Furthermore, the print data generation method of form 52 is the print data generation method of any one of forms 45 to 51,
In the printing data generation step, among pixel data corresponding to nozzles involved in banding in the second image data, pixel data having a pixel value with an ink ejection amount equal to or less than a predetermined amount Printing data in which dots are not formed for part or all of the data is generated.
Thereby, the same operation and effect as those of the printing data generation apparatus of form 35 can be obtained.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. 1 to 14 show a first embodiment of a printing apparatus, a printing apparatus control program, a printing apparatus control method, a printing data generation apparatus, a printing data generation program, and a printing data generation method according to the present invention. FIG.

First, the configuration of a printing apparatus 100 according to the present invention will be described with reference to FIG. FIG. 1 is a block diagram showing a configuration of a printing apparatus 100 according to the present invention.
The printing apparatus 100 is a line head type printing apparatus. As shown in FIG. 1, an image data acquisition unit 10 that acquires image data constituting a predetermined image from an external device, a storage device, or the like, and nozzles that are involved in banding. A second image data generation unit 11 for generating second image data obtained by converting the color mixture ratio of the image portion corresponding to the above so as to avoid or reduce banding, and an image of the second image data as a print medium (here Includes a printing data generation unit 12 that generates printing data for printing on a printing paper) and a printing unit 13 that prints an image of image data on a printing medium by an inkjet method based on the printing data. It has a configuration.

  The image data acquisition unit 10 expresses M-value (M ≧ 3) image data (for example, a gradation (luminance value) for each color (R, G, B) per pixel by 8 bits (0 to 255). Color image data), and such image data is externally transmitted via a network such as a LAN or WAN in accordance with a print instruction from an external device or an input device of the own device. From a recording medium such as a CD-ROM or a DVD-ROM obtained through a drive device such as a CD drive or a DVD drive (not shown) provided in the device, or from a storage device 70 (described later) of the device. It is possible to obtain. Furthermore, in the present embodiment, a function of performing color conversion processing on multi-value RGB data and converting it into multi-value CMYK (in the case of four colors) data corresponding to each ink of the print head 200 is also exhibited. It has become.

The second image data generation unit 11 includes a color conversion unit 11a, a nozzle information storage unit 11b, and a color conversion information storage unit 11c.
The color conversion unit 11a is a first image data (hereinafter referred to as CMYK image data) that has been CMYK converted based on the nozzle information stored in the nozzle information storage unit 11b and the color ratio information stored in the color ratio information storage unit 11c. The second image data is generated by converting the pixel value of the pixel data corresponding to the nozzles involved in banding in FIG.
The nozzle information storage unit 11b stores nozzle information for identifying nozzles involved in banding among a plurality of nozzles constituting the print head 200.

The color ratio information storage unit 11c stores color ratio information, which is information of a color conversion ratio for avoiding or reducing the occurrence of banding, for the nozzle modules corresponding to the respective colors of the print head 200 corresponding to a plurality of colors of ink. It has become. Here, the color ratio information includes information indicating the maximum mixing ratio of each color that can avoid banding, color replacement (or combination) information for ensuring graininess, and the color of the image portion corresponding to banding. Information necessary for changing the mixing ratio is included.
The print data generation unit 12 includes an N-value conversion processing unit 12a and an N-value conversion information storage unit 12b.

The N-value conversion processing unit 12a converts the second image data into N-values (M> N ≧ 2) based on the N-value information stored in the N-value information storage unit 12b, thereby using an inkjet method described later. Data for printing used in the printing unit 13, that is, conversion into data relating to whether or not dots of a predetermined color and a predetermined size are formed for each pixel data in the second image data (hereinafter referred to as dots) (Referred to as “binarization” or “halftoning” as appropriate).
The N-value information storage unit 12b stores N-value information necessary for the N-value process, such as a threshold value set for each type of dot size.
Here, FIG. 3 is a partially enlarged bottom view showing the structure of the print head 200 of the present invention provided in the printing unit 13, and FIG. 4 is a partially enlarged side view thereof.

  As shown in FIG. 3, the print head 200 includes a black nozzle module in which a plurality of nozzles N (18 in the figure) that exclusively discharge black (K) ink are linearly arranged in the nozzle arrangement direction. 50, and a plurality of nozzles N that also discharge yellow (Y) ink exclusively, and a yellow nozzle module 52 that is linearly arranged in the nozzle arrangement direction, and a plurality of nozzles that also discharge magenta (M) ink exclusively. The magenta nozzle module 54 in which the nozzles N are linearly arranged in the nozzle arrangement direction and the cyan nozzle in which a plurality of nozzles N that specifically discharge cyan (M) ink are arranged linearly in the nozzle arrangement direction The configuration includes four nozzle modules 50, 52, 54 and 56 such as the nozzle module 56. As shown in FIG. 3, the nozzle modules 50, 52, 54, and 54 are arranged so that the nozzles N of the same number in these four nozzle modules are aligned in the printing direction (perpendicular to the nozzle arrangement direction). 56 are integrally arranged. Accordingly, the plurality of nozzles N constituting each nozzle module are arranged linearly in the nozzle arrangement direction, and the nozzles N of the same number in the four nozzle modules are arranged linearly in the printing direction.

  Further, the print head 200 having such a structure is provided with a piezo (not shown) provided for each of the ink chambers. The ink supplied into the ink chamber (not shown) provided for each of the nozzles N1, N2, N3. By ejecting from each nozzle N1, N2, N3... By a piezoelectric element such as a piezo actuator, circular dots are printed on white printing paper, and the voltage applied to this piezoelectric element is multistage. By controlling the amount of ink discharged from the ink chamber, dots of different sizes can be printed for each nozzle N1, N2, N3. There are also cases where a single dot is formed by applying a voltage to the nozzles in two stages in a short time series in a time series and combining two ejections on the printing paper. In this case, by utilizing the fact that the ejection speed varies depending on the size of the dots, by ejecting the large dots following the small dots, the ink is landed at substantially the same position on the paper surface to form one larger dot. It is possible. Further, FIG. 4 shows that among the four nozzle modules 50, 52, 54, and 56, the black nozzle module 50, the sixth nozzle N6 from the left, has undergone the flight bending phenomenon, and the printing medium starts from the nozzle N6. Ink is ejected obliquely onto S, and the dots formed on the print medium S are thereby ejected from normal nozzles N7 adjacent to the nozzle N6 and in the vicinity of the dots formed on the print medium S. The state where it is formed is shown.

  Returning to FIGS. 1 and 3, the printing unit 13 receives ink from the nozzle modules 50, 52, 54 and 56 formed on the print head 200 while moving one or both of the print medium and the print head 200. Each of the ink jet printers is configured to form a predetermined image composed of a large number of dots by being ejected in the form of dots on the print medium S. In addition to the print head 200 described above, the print head 200 is connected to the print medium. A print head feed mechanism (not shown) that reciprocates in the width direction on S (a multi-pass type), a paper feed mechanism (not shown) for moving the print medium S, and the print head 200 based on the print data. It is composed of a print control mechanism (not shown) that controls ink ejection.

  The printing apparatus 100 is configured to implement the functions of the image data acquisition unit 10, the second image data generation unit 11, the print data generation unit 12, the printing unit 13, and the like on software, and the functions The computer system for executing the software which controls the hardware required for realization of is provided. As shown in FIG. 2, the hardware configuration of the computer system includes a central processing unit (CPU) 60 that is a central processing unit that performs various controls and arithmetic processing, and a RAM (main storage) (main storage). Random Access Memory (Random Access Memory) 62 and ROM (Read Only Memory) 64, which is a read-only storage device, are connected by various internal and external buses 68 such as PCI (Peripheral Component Interconnect) bus and ISA (Industrial Standard Architecture) bus. In addition, an external storage device (Secondary Storage) 70 such as an HDD, an output device 72 such as a printing unit 13, a CRT, and an LCD monitor, an operation panel and a mouse are connected to the bus 68 via an input / output interface (I / F) 66. A network cable for communication with an input device 74 such as a keyboard, a scanner, and a print instruction device (not shown). Le L is obtained by connecting a.

  When the power is turned on, a system program such as BIOS stored in the ROM 64 or the like is stored in various dedicated computer programs stored in the ROM 64 in advance, or in a CD-ROM, DVD-ROM, flexible disk (FD), or the like. Various dedicated computer programs installed in the storage device 70 are loaded into the RAM 62 via a medium or a communication network such as the Internet, and the CPU 60 executes various resources according to instructions described in the program loaded in the RAM 62. Each function as described above is realized on software by performing predetermined control and arithmetic processing by making full use of.

  Furthermore, in the printing apparatus 100, the CPU 60 activates a predetermined program stored in a predetermined area of the ROM 64, and executes the printing process shown in the flowchart of FIG. 5 according to the program. As described above, the print head 200 for forming dots can generally form dots of a plurality of types of colors such as four colors and six colors almost simultaneously, but in the present embodiment, In the following description, it is assumed that each of the CMYK four-color inks is configured by nozzle modules.

FIG. 5 is a flowchart illustrating a printing process in the printing apparatus 100.
When the printing process is executed by the CPU 60, as shown in FIG. 5, first, the process proceeds to step S100.
In step S100, the image data acquisition unit 10 receives print instruction information from an external device connected via the network cable L, or has received print instruction information via the input device 74. Thus, it is determined whether or not there is a print instruction. If it is determined that there is a print instruction (Yes), the process proceeds to step S102. If not (No), the determination process is repeated until there is a print instruction.

  When the process proceeds to step S102, the image data acquisition unit 10 outputs the image data corresponding to the print instruction to the external device, a recording medium such as a CD-ROM or a DVD-ROM, and a storage device 70 such as an HDD as described above. It is determined whether or not the first image data has been acquired. If it is determined that the first image data has been acquired (Yes), the acquired first image data is used as the second image data generation unit. 11 and the process proceeds to step S104. If not (No), a response indicating that printing is not possible is sent to the print instruction source, and then the print process for the print instruction is abandoned and the process proceeds to step S100. .

Here, the first image data is data in which a plurality of M-value pixel data corresponding to each color of CMYK is arranged in a matrix, and the row direction thereof coincides with the nozzle arrangement direction of the print head 200. The column direction coincides with the print direction of the print head 200.
When the process proceeds to step S104, the second image data generation unit 11 executes the second image data generation process to generate the second image data, and the process proceeds to step S106.

In step S106, the print data generation unit 12 executes print data generation processing to generate print data, and the process proceeds to step S108.
In step S108, the printing data generation unit 12 outputs the printing data generated in step S106 to the printing unit 13, and the process proceeds to step S110.
In step S110, the printing unit 13 executes a printing process based on the printing data from the printing data generation unit 12, and proceeds to step S100.

Next, the generation processing of the second image data in step S104 will be described in detail based on FIG.
FIG. 6 is a flowchart showing second image data generation processing in the second image data generation unit 11 of the printing apparatus 100.
The second image data generation process is a process of generating second image data obtained by changing the pixel value of the pixel data of the image portion corresponding to the nozzles involved in banding based on color ratio information prepared in advance. However, when executed in step S104, as shown in FIG. 6, first, the process proceeds to step S200.

In step S200, the color ratio conversion unit 11a determines whether or not CMYK image data has been acquired from the image data acquisition unit 10, and if it is determined that it has been acquired (Yes), the process proceeds to step S202. (No) continues the determination process until acquisition.
When the process proceeds to step S202, the color ratio conversion unit 11a reads the nozzle information from the nozzle information storage unit 11b and stores the read nozzle information in a predetermined area of the RAM 62, thereby acquiring the nozzle information. The process proceeds to S204.

In step S204, the color ratio conversion unit 11a reads the color ratio information from the color ratio information storage unit 11c, and stores the read color ratio information in a predetermined area of the RAM 62, thereby acquiring the color ratio information. The process proceeds to S206.
In step S206, the color ratio conversion unit 11a selects nozzle information of a nozzle module for which the second image data generation process has not been processed (hereinafter referred to as an unprocessed nozzle module) from the nozzle information acquired in step S202. The process proceeds to S208.

In step S208, the color ratio conversion unit 11a selects nozzle information corresponding to the unprocessed nozzle number from the nozzle information of the unprocessed nozzle module selected in step S206, and the process proceeds to step S210.
In step S210, the color ratio converter 11a determines whether the nozzle is involved in banding based on the nozzle information of the unprocessed nozzle number selected in step S208 (hereinafter referred to as the selected nozzle number). If it is determined that the user is involved (Yes), the process proceeds to step S212. If not (No), the process proceeds to step S220.

When the process proceeds to step S212, the color ratio conversion unit 11a selects pixel data related to the nozzle of the selected nozzle number from the CMYK image data, and the process proceeds to step S214.
In step S214, the color ratio conversion unit 11a analyzes the color mixture ratio of the pixel data selected in step S212, and the process proceeds to step S216. Here, the color mixture ratio analysis processing corresponds to these nozzles for image portions corresponding to nozzles related to banding (hereinafter referred to as abnormal nozzles) and nozzles of other colors related to the abnormal nozzles. In this process, the pixel value of each pixel data to be analyzed is analyzed to obtain what ratio the mixing ratio of each color (ink ejection ratio of each color) is. Here, in the present embodiment, the abnormal nozzles are a total of 11 nozzles including five nozzles on the left and right, centering on the nozzles that cause banding, such as nozzles that cause flight bends and nozzles that have poor ink ejection. Will be shown.

  In step S216, the color ratio conversion unit 11a performs banding on the pixel values of the pixel data corresponding to the nozzles of each color related to the nozzle of the selected nozzle number selected in step S212 based on the color ratio information acquired in step S204. The value is changed to a value that can be avoided to the maximum and the color after changing the pixel value is in the same color range as the color before changing, and the process proceeds to step S218. Here, the value within the same color range is, for example, that the color difference ΔE between the color before change and the color after change is “0 ≦ ΔE ≦ 0.7 in the L * a * b * color system. The value falls within the range. By changing the value so as to be within the range of this value as much as possible, the color before the change and the color after the change are perceived as the same color by most people.

  In this embodiment, the color ratio conversion process reduces the ink discharge amount of the abnormal nozzle to 1 when the discharge amount of the color ink corresponding to the abnormal nozzle can be reduced to ¼ or less of the use limit discharge amount. / 4 or less (changes the value of the corresponding pixel data), and the N-value processing unit 12 uses a nozzle (or a nozzle with poor ink ejection) that causes a flying curve among abnormal nozzles. This is a process of preventing the dots from being formed (does not form dots). On the other hand, if the ink discharge amount of the abnormal nozzle cannot be less than ¼ of the use limit discharge amount, the ink discharge amount of the abnormal nozzle is reduced to a discharge amount that makes banding inconspicuous (the value of the corresponding pixel data And the effect of the decrease on the color before the change is compensated by changing the ink discharge amount of the nozzles of other colors (changing the value of the corresponding pixel data).

In step S218, the color ratio conversion unit 11a determines whether or not all nozzle numbers for the selected nozzle module have been selected. If it is determined that selection has been made (Yes), the process proceeds to step S220; No) moves to step S210.
When the process proceeds to step S220, the color ratio conversion unit 11a determines whether or not all nozzle modules have been selected. If it is determined that they have been selected (Yes), the series of processes ends and the original process is completed. If not (No), the process proceeds to step S208.

Next, based on FIG. 7, the print data generation processing in step S106 will be described in detail.
FIG. 7 is a flowchart illustrating print data generation processing in the print data generation unit 12 of the printing apparatus 100.
The print data generation process is a process for generating print data obtained by performing N-value processing on the second image data generated by the second image data generation unit 11, and is executed in step S106. Then, as shown in FIG. 7, first, the process proceeds to step S300.

In step S300, the N-value conversion processing unit 12a determines whether or not the second image data is acquired from the second image data generation unit 11, and if it is determined that the acquisition is performed (Yes), the process proceeds to step S302. If not (No), the determination process is continued until acquisition.
In step S302, in the N-value conversion process 11a, the N-value information is read from the N-value information storage unit 12b, and the read N-value information is stored in a predetermined area of the RAM 62. And the process proceeds to step S304.

In the present embodiment, the N-value information corresponds to a threshold value of density value and a dot formation size for determining whether to form “do” or “not form” dots for a plurality of types of dot formation sizes. The density value after N-value conversion is included. That is, the value (density value) of the pixel data constituting the image data is compared with the threshold value of the above-described density value, and when it is equal to or larger than the threshold value, it is determined that a dot of that size is formed. It is determined that no dot of that size is formed.
In step S304, the N-value conversion processing unit 12a selects pixel data that has not been subjected to N-value conversion processing from the second image data, and proceeds to step S306.
In step S306, the N-value conversion processing unit 12a converts the selected pixel data into N-values based on the N-value information acquired in step S302, and the process proceeds to step S308.

  Here, the N-value conversion processing converts the density value of the pixel data to “1” when it is determined that the dot is “formed” based on the determination result by the density value comparison described above. Is determined to be “not formed”, it is converted to “0”. However, the largest dot formation size determined to be “form” is set as the dot formation size of the pixel data, and the dot formation size information (size identification information) is determined to be “form”. Corresponds to the numerical value “1”. Accordingly, the information set for each size corresponds to the information of each dot formation size, and in this embodiment, as shown in FIG. 13, the dots are not formed according to each density value. , Including four types of dot formation sizes “small”, “medium”, and “large”, so that the quaternization processing is substantially performed.

In step S308, in the N-value conversion processing unit 12a, the difference between the pixel value of the selected pixel data before N-value conversion and the pixel value of the pixel data after N-value conversion is used as an error, and the error is converted into the selected pixel data. An error diffusion process for diffusing to pixel values corresponding to pixels around the pixel is executed, and the process proceeds to step S310.
Here, in the present embodiment, the N-value processing is performed using an error diffusion method capable of area gradation expression. However, the present invention is not limited to this, and in processing focused on text or the like, each pixel is simply set. It is possible to use a method such as dithering as a method for determining a value by comparing the threshold values, and as another area gradation expression method.

In step S310, the N-value conversion processing unit 21a determines whether or not the N-value conversion processing is completed for all the pixel data of the second image data. If it is determined that the N-value conversion processing is completed (Yes), a series of steps are performed. The process ends and the process returns to the original process. If not (No), the process proceeds to step S304.
Here, the second image data after the N-value conversion processing is the print data, and the print data includes information on whether or not dots are formed and identification information on the dot size to be formed.

Next, the operation of the present embodiment will be described with reference to FIGS.
Here, FIG. 8A is a diagram showing an example of a dot pattern formed by the cyan nozzle module 56 without an abnormal nozzle that generates a so-called flight curve, and FIG. FIG. 5 is a diagram showing an example of a dot pattern formed when a nozzle N6 has a flying curve phenomenon. FIG. 9A is a diagram showing a dot pattern formed with a resolution of ½, in which the nozzle N6 in the cyan nozzle module 56 is not used, and FIG. 9B is a diagram showing the nozzle N6 in the cyan nozzle module 56. It is a figure which shows an example of the dot pattern formed by reducing the ink discharge amount of the abnormal nozzle containing. FIG. 10A is a diagram showing an information table showing the relative flight bending amount of each nozzle, and FIG. 10B is an information table showing whether ink is not ejected from each nozzle included in the nozzle information. FIG. FIG. 11A is a diagram illustrating an example of an image before the color ratio change, in which abnormal nozzles are formed by nozzles corresponding to CMYK-containing colors, and FIG. 11B is a color ratio conversion of FIG. It is a figure which shows the subsequent image. FIG. 12 is a diagram illustrating an information table indicating the banding avoidable mixing ratio for each color included in the color ratio information. FIG. 13 is a diagram illustrating an example of N value information and threshold information for each N value with respect to the dot size. FIG. 14 is a diagram illustrating an example of an error diffusion matrix used for the N-ary processing.

As shown in FIG. 8A, the dot pattern formed by the cyan nozzle module 56 having no abnormal nozzle that generates a flying curve has nozzle intervals such as “white stripes” and “dark stripes” as described above. Banding that occurs due to the deviation is not generated.
On the other hand, as for the printing result by the cyan nozzle module 56 including the nozzle that generates the flight curve, the dot formed by the nozzle N6 is formed by the normal nozzle N7 adjacent to the right as shown in FIG. 8B. As a result, a “white streak” is generated between the dot formed by the nozzle N6 and the dot formed by the nozzle N5 adjacent to the left side. Yes.

Further, although not shown in the figure, due to an ink ejection failure (non-ejection) of the nozzle N6 in the cyan nozzle module 56, a dot that should originally be formed is not formed, but between the dots formed by the nozzle N5 and the nozzle N7. “White streaks” may occur.
The above-mentioned “white streaks” are so-called “solid-colored” printed matter, and when the printing paper is white and the ink is black, etc. The quality of the product will be extremely deteriorated.

  Further, as described above, the nozzle N6 is displaced by the distance a due to the flight curve, so that the distance between the nozzle N6 and the nozzle N7 on the right side of the nozzle N6 is reduced by the distance a. The density of the dots to be formed becomes high (the dots may overlap), and this portion becomes a “dark streak” and becomes conspicuous, thereby extremely deteriorating the quality of the printed matter.

  Here, in order to avoid the occurrence of banding such as “white streaks” or “dark streaks”, as shown in FIG. 9A, the nozzle N6 is not used (dots are not formed), and The resolution of the image formed by the abnormal nozzle is changed to half of the resolution before the change shown in FIG. 8B (this reduces the number of dots formed), or as shown in FIG. 9B. As described above, it can be understood from the dot patterns in FIGS. 9A and 9B that the ink discharge amount (number of dots formed) of the entire abnormal nozzle can be reduced while using the nozzle N6. It is valid.

  However, as described above, if the number of dot formation (ink discharge amount) of abnormal nozzles (cyan nozzles) is reduced in order to avoid banding, banding itself can be avoided, but it is configured by mixing with other colors. There is a problem that the color before the reduction has been changed to another color because the balance of the mixing ratio is lost. This is also true for reducing the dot formation size, and reducing the dot size (decreasing the ink discharge amount) leads to a decrease in the density of the color. This also breaks the balance of the color mixing ratio.

  Therefore, in the printing apparatus 100 according to the present invention, the value of the pixel data of the color corresponding to the abnormal nozzle in the CMYK image data is changed so that the ink ejection ratio of the abnormal nozzle is a ratio that can avoid banding, Pixels corresponding to the nozzles of other colors related to the abnormal nozzles in the CMYK image data so that the color before the change constituted by the abnormal nozzles and the nozzles of the other colors does not deviate from the same color range due to this change. By generating second image data in which the value of the data is changed according to the changed value of the pixel value corresponding to the abnormal nozzle, the second image data is subjected to N-value processing, thereby avoiding banding or Print data that can be reduced and can solve the above problems is generated.

  First, when the printing apparatus 100 receives printing instruction information from an external apparatus or the like at the image data acquisition unit 10 (step S100), the first image data corresponding to the printing instruction information is the transmission source of the printing instruction information. CMYK image data acquired from an external device or the like and converted from CMYK color information (RGB) of the acquired first image data is transmitted to the second image data generation unit 11 (step S102). When the second image data generation unit 11 acquires CMYK image data from the image data acquisition unit 10, the second image data generation unit 11 executes generation processing of second image data (step S104).

  The generation process of the second image data is started by acquiring the CMYK image data transmitted from the image data acquisition unit 10 in the color ratio conversion unit 11a (step S200). First, the nozzle information is stored in the nozzle information storage unit 11b. And the read nozzle information is stored in a predetermined area of the RAM 62 (step S202). Next, the color ratio information is read from the color ratio information storage unit 11c, and the read color ratio information is stored in a predetermined area of the RAM 62 (step S204).

  After obtaining the nozzle information and the color ratio information, the color ratio conversion unit 11a obtains nozzle information corresponding to the nozzle modules 50, 52, 54, and 56 respectively corresponding to the CMYK inks from the nozzle information. One nozzle information corresponding to the unprocessed nozzle module is selected from the list (step S206). In this embodiment, the nozzle information is a data table for each nozzle module, and for each nozzle module, information indicating the relative flight bending amount for each nozzle number constituting the nozzle module is prepared as a table. Has been. That is, for example, in the case of cyan ink as an example, these data tables have a relative flight bending amount (relative discharge amount) for each nozzle number corresponding to each nozzle constituting the cyan nozzle module, as shown in FIG. Accuracy information) is associated.

  Further, when the color ratio conversion unit 11a selects the data table for the nozzle module, the color ratio conversion unit 11a then selects an unprocessed nozzle number in the data table (step S208) and indicates the relative flight curve amount corresponding to the selected nozzle number. Based on the information, it is determined whether or not the selected nozzle is involved in banding (step S210). Here, in the present embodiment, when the relative flight bending amount of the selected nozzle is equal to or larger than a preset threshold value (for example, 4 [μm]), it is determined that the selected nozzle is involved in banding (step) If the relative flight bend amount of the selected nozzle is smaller than the threshold, it is determined that the selected nozzle is not involved in banding (“No” branch in step S210).

  Hereinafter, processing when it is determined that the selected nozzle is involved in banding will be described. When the selected nozzle is involved in banding, the color ratio conversion unit 11a first selects pixel data related to the selected nozzle from the first image data (step S212), and analyzes the color mixture ratio of the pixel data (step S212). Step S214). Here, the pixel data related to the selected nozzle is pixel data corresponding to the abnormal nozzle (11 nozzles) described above and other nozzles involved in printing the image portion corresponding to the abnormal nozzle. is there.

  For example, when the flight bend occurs in the nozzle N6 of the cyan nozzle module 56, as described above, five nozzles on the left and five on the right centering on the nozzle N6 (total of 11 nozzles (nozzles N1 to N11)). Is an abnormal nozzle, pixel data corresponding to the abnormal nozzle (nozzles N1 to N11) and an image part corresponding to the abnormal nozzle are printed. For example, nozzles N1 to N11 of the black nozzle module 50, yellow nozzle Pixel data corresponding to the nozzles N1 to N11 of the module 52 and the nozzles N1 to N11 of the magenta nozzle module 54 are obtained.

In addition, the color mixture ratio analysis process determines the ink discharge amounts of the nozzles N1 to N11 of each color from the pixel values of the pixel data corresponding to the nozzles N1 to N11 of the nozzle modules 50, 52, 54, and 56 described above. This is a process for calculating a percentage of the maximum dischargeable amount.
For example, as shown in FIG. 11A, it is assumed that the color mixing ratio is 50% for the cyan nozzle, 90% for the magenta nozzle, 40% for the yellow nozzle, and 10% for the black nozzle.

Here, the characteristics of the CMYK ink used in the present embodiment will be described.
A general printing device basically provides full color by preparing inks corresponding to three colors of C (Cyan), M (Magenta), and Y (Yellow), and changing the printing ratio. ing. Further, K (Black) ink for improving the printing quality is added to the CMY to realize printing based on the CMYK.

  For example, when printing with 100% solids for each color using CMYK four color inks, a total of 400% ink of 100% × 4 colors will be deposited on the paper. If one color is printed and then the next color is printed after waiting for the ink to dry, there is no particular problem even if it is 400%. For example, in the case of a high-speed offset rotary press, it remains wet. As a result, ink is deposited one after another, and a phenomenon in which ink suddenly becomes difficult to be deposited when the amount of ink on paper exceeds 300% occurs. Therefore, if the viscosity of the ink to be placed next is high, the ink already on the paper may be peeled off.

  Also in the case of inkjet, for example, if a high-density part such as a shadow part is expressed with only CMY three-color ink, the amount of three colors to be overlaid increases, and the total amount of ink in that part is large. Therefore, the ink absorption rate on the paper surface becomes a problem, and the paper surface becomes sticky and causes problems such as a wavy state. Therefore, in general inkjet printers and the like, the CMY ink in the high density portion is replaced with black ink (K) to reduce the total amount of CMYK four-color ink so that the paper with ink does not feel sticky. . Such an idea is generally called UCR (Under Color Removal).

  In consideration of the above under color removal, in the present embodiment, based on the acquired color ratio information, the colors of the CMYK four colors are represented by the relationship shown in the following equations (1) and (2). Convert the mixing ratio. However, the actual ink has a complicated influence on each ink, and the ink mixing ratio of the simple mathematical formula as in the following formulas (1) and (2) does not become, so in the actual processing, the following formula (1 ) And (2), instead of the simplified conversion equations, conversion equations that take ink characteristics into consideration may be used. In this embodiment, for convenience of explanation, the color ratio conversion process will be described using the following expressions (1) and (2).

  (C1, M1, Y1, K1) → (C2, M2, Y2, K2) (1)

  C1 + K1 = C2 + K2, M1 + K1 = M2 + K2, Y1 + K1 = Y2 + K2, (2)

  However, C1, M1, Y1, and K1 are the ink ejection ratios of cyan, magenta, yellow, and black before the color ratio is changed, and the C2, M2, Y2, and K2 are cyan after the color ratio is changed. , Magenta, yellow, and black ink ejection ratios.

  Here, as shown in FIG. 12, the color ratio information includes an information table in which the maximum discharge ratio that can avoid banding is associated with each color of CMYK. That is, as shown in FIG. 12, when a nozzle corresponding to cyan ink is involved in banding, the discharge ratio of the associated cyan ink nozzle is at most 30%, and a nozzle corresponding to magenta ink is involved in banding. If the nozzle corresponding to yellow ink is involved in banding, the discharge ratio of the corresponding magenta ink nozzle is at most 60%. In addition, when the nozzle corresponding to the black ink is involved in banding, the pixel data corresponding to each nozzle in the first image data is set so that the discharge ratio of the corresponding black ink nozzle is 20% at the maximum. Change the pixel value. The amount reduced by this change is compensated by changing the ink ejection ratio of the nozzles corresponding to other colors.

  Here, since the nozzle corresponding to the cyan ink in FIG. 11A is involved in banding as described above, in order to avoid or reduce the occurrence of banding due to this, for example, ejection before changing the cyan ink is performed. As shown in FIG. 12, the pixel value of the pixel data corresponding to the banding occurrence position in the first image data is changed in order to change the ratio of 50% to 30%, which is the highest ratio that can avoid banding, as shown in FIG. To do.

  Then, according to the above equations (1) and (2), the discharge amount of the black ink is changed from 10% before the change to 30% by the amount that the cyan ink discharge ratio is reduced by 20% from 50% to 30%. This is compensated by changing the pixel value of the pixel data corresponding to the abnormal nozzle in the first image data so as to increase by 20%, and magenta and yellow affected by increasing the discharge amount of black ink by 20%. The pixel value of the pixel data corresponding to the abnormal nozzle in the first image data is changed so that the ink ejection amount of each of the first image data decreases by 20% (step S216).

  That is, for the cyan ink involved in banding, the pixel value is changed so that 50 + 10 = 30 + K2, that is, K2 = 30 (%), so that the relationship of C1 + K1 = C2 + K2 in the above equation (2) is established. , 90 + 10 = M2 + 30, that is, M2 = 70 (%) so that the relationship of M1 + K1 = M2 + K2 and Y1 + K1 = Y2 + K2 holds for magenta ink and yellow ink, which are affected by setting K2 to 30%. The pixel value is changed, and the pixel value is changed so that 20 + 10 = Y2 + 30, that is, Y2 = 0 (%).

  In this way, by changing the pixel values of the pixel data corresponding to the nozzles involved in banding and the nozzles of other colors related to this nozzle so as to have the color mixture ratio as described above, FIG. As shown in (2), it is possible to generate second image data that can form a print image that can maintain the same color range before the change and avoid or reduce banding.

  In the above example, since the discharge ratio of yellow ink was 20%, the ink discharge ratio of nozzles involved in banding could not be reduced to 25% or less. For example, (C1, M1, Y1) , K1) = (50 (%), 30 (%), 15 (%), 10 (%)), the color is composed, and the magenta nozzle used for the composition of the color is involved in the banding. In this case, according to the above formulas (1) and (2), (C2, M2, Y2, K2) = (45 (%), 25 (%), 10 (%), 15 (%)) It is possible to change the color mixing ratio. Thus, the discharge ratio of magenta ink can be 25%, which is 1/4 or less of the maximum discharge ratio. In such a case, it is possible to configure the color even when the magenta print resolution is ½, so that not only the nozzles that cause banding, here, the nozzles that generate flying bends, but also the ink ejection It is also possible to target nozzles with defective ejection whose amount is different from the ideal amount, and these nozzles themselves can be made unusable.

In addition, for example, the nozzles with defective ejection are information (0 (normal ejection), 1 ( Judgment is made based on a table associated with non-ejection (that is,))).
In the present embodiment, in such a case, for the pixel data corresponding to the nozzle that causes banding in the magenta nozzle module, information indicating that the nozzle is not used (information not to form dots) Is added to the pixel data corresponding to the abnormal nozzle, and the N-value conversion processing unit 12 adds information for halving the print resolution.

  The above-described determination process is performed on all nozzles of all nozzle modules of the print head 200, and for the nozzles determined to be involved in banding, the abnormal nozzles including the nozzles and the abnormal nozzles in the CMYK image data are used. By performing processing to change the pixel value of the pixel data corresponding to the related nozzle so that the color mixing ratio can avoid or reduce banding and is in the same color range as the color before the change, Two-image data is generated. Then, the generated second image data is transmitted to the print data generating unit 12, and the print data generating unit 12 executes a print data generating process (step S106).

The print data generation process is started by determining that the second image data transmitted from the second image data generation unit 11 is acquired in the N-value conversion processing unit 12a (step S300). The N-value information is obtained by reading the N-value information from the value-information storage unit 11b and storing it in a predetermined area of the RAM 62 (step S302). Here, as described above, the N-value information includes an N-value threshold corresponding to each dot formation size information and a density value.
Upon obtaining the N-value information, the N-value processing unit 11a selects pixel data that has not been processed by the N-value processing in the second image data based on the N-value information (step S304). N-ary processing is performed on the pixel data (step S306).

  In the present embodiment, the N-value conversion processing is performed when the original pixel value (density value or luminance value) of the selected pixel data has an 8-bit “256” gradation, for example, if the pixel value is a density value. As shown in FIG. 13, when the original pixel value is less than “0” to “42”, the pixel values are grouped into “0” and the N value is set to “0” (no dot is formed), When the original pixel value is less than “42” to “126”, the pixel values are grouped into “84” and the N value is set to “1” (forms a dot) for a small dot. When the pixel values are less than “126” to “210”, the pixel values are grouped into “168”, the N value is set to “1” for the medium dot, and the original pixel values are “210” to “255”. "(May be 255 or more), the pixel values are grouped into" 255 "and the N value is set to a large dot. It is adapted to "1" Te.

The above example is a case where the density is adopted as the pixel value. When the luminance is adopted as the pixel value, a value opposite to the density is taken for each size dot.
In the present embodiment, the data in the gradation direction of the image is converted into the gradation direction and the area gradation for each color of CMYK in accordance with the performance of the ink ejection mechanism by the N-value conversion processing. As shown in FIG. 13, if the ink ejection mechanism is capable of printing with three types of dot formation sizes, four gradations are expressed for each ink including the state in which no dots are formed. Is possible. That is, the four gradations and the area gradation are combined to reproduce a full gradation. When the dot size is limited to only one type, a full gradation is reproduced with two gradations indicating whether or not to form and an area gradation.

As a technical method for controlling the dot size in this way, for example, in the case of a method using a piezo actuator for the print head, the voltage applied to the piezo element is changed to control the ink ejection amount. This makes it easy to implement.
When the N-value conversion process is performed on the selected pixel data, an error is calculated between the luminance value before the N-value conversion process of the selected pixel data and the brightness value corresponding to the dot number after the N-value conversion. Based on the error diffusion matrix shown in FIG. 14, the calculated error is subjected to error diffusion processing in which the N-value conversion processing around the pixels of the selected pixel data is diffused to unprocessed pixels (step S308).

  This error diffusion process is a conventionally known process. For example, in the case of a binarization process, the target pixel to be processed can be expressed by 8 bits (256 gradations), and the gradation is “ In the case of “101”, in the normal binarization process, since the gradation is less than “128” which is the threshold value (intermediate value), the pixel is processed as “0”, that is, a pixel not forming a dot. 101 "is discarded as it is. On the other hand, in the case of error diffusion processing, the “101” is diffused to the surrounding unprocessed pixels according to a predetermined error diffusion matrix. Since only the normal binarization processing does not reach the threshold value as in the case of the selected pixel, it has been processed as “no dot is formed”, but the density value exceeds the threshold value by receiving the error of the selected pixel. It is handled such as “form dots”, and binarized data closer to the original image data can be obtained.

That is, the above-described density value for each dot formation size is used in error diffusion processing, and the difference between the density value of the original pixel data and the density value of the corresponding dot formation size after N-value conversion is an error. It is diffused to surrounding unprocessed pixel data.
Further, as described above, when the information that disables the nozzles that cause banding and the information that halves the resolution are added to the selected pixel data in the second image data, N In the value conversion process, the selected pixel data is unconditionally converted to the nozzle number “0”, and the error is diffused to surrounding pixels. The pixel data corresponding to the abnormal nozzle including the selected pixel data is subjected to N-value processing so that the selected pixel data includes half of the selected pixel data and does not form dots.

When the N-value conversion process is completed for all pixel data in the second image data (step S310), the N-value conversion processing unit 12 performs the second process on which the N-value conversion process and the error diffusion process have been performed. The image data is used as print data, and the print data is output to the printing unit 13 (step S108).
Then, in the printing unit 13, dots are formed (printed) on the printing medium using the print head 200 based on the printing data output from the printing data generation unit 12 at a color mixing ratio corresponding to the second image data. (Step S110). As a result of this formation, as shown in FIG. 9A or 9B, the dot formation pattern corresponding to the nozzles of the colors involved in banding becomes a pattern in which the ink discharge ratio is such that banding can be avoided, and FIG. As shown in FIG. 5B, the dot formation result when normal printing data is generated without considering the state in which the flight curve occurs in the nozzle N6 (without performing the color ratio conversion process described above) is compared. When viewed from a macro viewpoint, image quality degradation such as a slight roughness may occur compared to the ideal print result of FIG. 8A, but it is visually recognized as white stripes and dark stripes. Can be made inconspicuous, and the image quality as a whole can be improved.

  In the first embodiment, the image data acquisition unit 10 corresponds to the image data acquisition unit of the form 1 or 28, and the second image data generation unit 11 includes the forms 1, 2, 7, 28, 29, and 34. The print data generation unit 12 corresponds to any one of the first, eighth, 28, and 35 print data generation units, and the print unit 13 corresponds to any one of the second image data generation units. This corresponds to the printing means of the first form.

  In the first embodiment, step S102 corresponds to the image data acquisition step of any one of forms 11, 20, 36, and 45, and step S104 is the form 11, 12, 17, 20, 21, 26. , 36, 37, 42, 45, 46 and 51, corresponding to any one of the second image data generation steps, step S106 is one of the forms 11, 18, 20, 27, 36, 43, 45 and 52. Step S110 corresponds to the printing step of Form 11 or 20, corresponding to one printing data generation step.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to the drawings. 15 to 17 show a second embodiment of a printing apparatus, a printing apparatus control program, a printing apparatus control method, a printing data generation apparatus, a printing data generation program, and a printing data generation method according to the present invention. FIG.

  Here, the configurations of the printing apparatus and the computer system according to the present embodiment are the same as those in FIGS. 1 and 2 of the first embodiment. However, in the present embodiment, in addition to the four colors of CMYK, the print head 200 has an LC (Light Cyan) that is similar in color to cyan and only different in saturation, and an LM that is similar in color to magenta and has only different saturation (LM) Light Magenta) is equipped with a nozzle module corresponding to each of the two colors. In the present embodiment, the second image data generation process performed in step S104 in FIG. 5 of the first embodiment is changed to that in FIGS.

  The second image data generation process of FIGS. 15 and 16 is the same as the first embodiment, but corresponds to cyan and light cyan by increasing two colors of light cyan and light magenta. When these nozzles are involved in banding, the similar colors are interpolated with each other. Similarly, when nozzles corresponding to magenta and light magenta are involved in banding, these similar colors Thus, the point of interpolating each other is different from the first embodiment.

Hereinafter, only different parts from the first embodiment will be described, and description of parts overlapping with the first embodiment will be omitted.
Based on FIG. 15, the second image data generation processing in step S104 in the present embodiment will be described in detail.
FIG. 15 is a flowchart illustrating second image data generation processing in the second image data generation unit 11 of the printing apparatus 100.

  This second image data generation process is performed by using a nozzle that participates in banding for an image portion that corresponds to a plurality of color nozzles including a nozzle that participates in banding and a nozzle that is similar in color to the nozzle that is involved in the banding. The mixing ratio of multiple colors, centering on the color mixing ratio between the color of the nozzle and the color of the nozzle involved in the banding and similar colors, is within the same color range as the color before the change, and banding is avoided or reduced This is a process for generating the second image data that has been changed to have a possible color mixing ratio, and when it is executed in step S104, it first proceeds to step S400 as shown in FIG. .

In step S400, the color ratio conversion unit 11a determines whether or not CMYK image data has been acquired from the image data acquisition unit 10. If it is determined that acquisition has been performed (Yes), the process proceeds to step S402. (No) continues the determination process until acquisition.
When the process proceeds to step S402, the color ratio conversion unit 11a performs a process of color-splitting the CMYK image data into six colors of four colors of CMYK and LC and LM to generate second CMYK image data, and step S404. Migrate to

In step S404, the color ratio conversion unit 11a reads the nozzle information from the nozzle information storage unit 11b, stores the read nozzle information in a predetermined area of the RAM 62, acquires the nozzle information, and proceeds to step S406. .
In step S406, the color ratio conversion unit 11a selects the nozzle information of the unprocessed nozzle module from the nozzle information acquired in step S404, and the process proceeds to step S408.

In step S408, the color ratio conversion unit 11a selects nozzle information corresponding to the unprocessed nozzle number from the nozzle information of the unprocessed nozzle module selected in step S406, and the process proceeds to step S410.
In step S410, the color ratio converter 11a determines whether the nozzle is involved in banding based on the nozzle information of the unprocessed nozzle number selected in step S408 (hereinafter referred to as the selected nozzle number). If it is determined that the user is involved (Yes), the process proceeds to step S412. If not (No), the process proceeds to step S416.

When the process proceeds to step S412, the color ratio conversion unit 11a selects pixel data related to the nozzle of the selected nozzle number from the second CMYK image data, and the process proceeds to step S414.
In step S414, the color ratio conversion unit 11a performs a color ratio conversion process on the pixel data selected in step S412 and proceeds to step S416.

In step S416, the color ratio conversion unit 11a determines whether or not all nozzle numbers for the selected nozzle module have been selected. If it is determined that selection has been made (Yes), the process proceeds to step S418; No) moves to step S410.
When the process proceeds to step S418, the color ratio conversion unit 11a determines whether or not all nozzle modules have been selected. If it is determined that they have been selected (Yes), the series of processes is terminated and the original process is completed. If not (No), the process proceeds to step S406.

Further, the color ratio conversion process in step S414 will be described in detail with reference to FIG.
FIG. 16 is a flowchart illustrating color ratio conversion processing focusing on light cyan in the second image data generation unit 11 of the printing apparatus 100.
In this color ratio conversion process, when the nozzles involved in banding are nozzles corresponding to light cyan, these nozzles are centered on the light cyan ink discharge amount and the cyan ink discharge amount of the same color. In the process of converting the color mixture ratio of pixel data corresponding to the nozzles of a plurality of colors to be within the same color range as the color before the ratio conversion and to a color mixture ratio that can avoid or reduce banding If executed in step S414, the process first proceeds to step S500 as shown in FIG.

In step S500, the color ratio conversion unit 11a reads the color ratio information from the color ratio information storage unit 11c, and stores the read color ratio information in a predetermined area of the RAM 62, thereby acquiring the color ratio information. The process proceeds to S502.
In step S502, the color ratio conversion unit 11a determines whether there is a nozzle of the same color as the color of the selected nozzle. If it is determined (Yes), the process proceeds to step S504; ) Proceeds to step S514.

In step S504, in the color ratio conversion unit 11a, based on the color ratio information, the pixel value of the pixel data corresponding to the selected nozzle so that the ink discharge amount of the selected nozzle becomes a discharge amount that can avoid or reduce banding. Is changed to step S506.
In step S506, in the color ratio conversion unit 11a, the ink discharge amount of the nozzle of the same color as the ink color of the selected nozzle (hereinafter referred to as the same color nozzle) is compensated for the discharge amount of the selected nozzle decreased in step S504. Thus, the pixel value of the pixel data corresponding to the similar color nozzle is changed, and the process proceeds to step S508.

In step S508, the color ratio conversion unit 11a determines whether or not integration with other colors is necessary from the viewpoint of graininess or the like. If it is determined that it is necessary (Yes), the process proceeds to step S510. If not (No), the series of processing ends and the processing returns to the original processing.
When the process proceeds to step S510, the color ratio conversion unit 11a changes the pixel value of the pixel data corresponding to the similar color nozzle so that the ink discharge amount of the similar color nozzle decreases, and the process proceeds to step S512.

In step S512, the pixel value of the pixel data corresponding to the nozzle of the other color so that the decrease in the ink discharge amount of the similar color nozzle is compensated by the ink discharge amount of the nozzle of the other color in the color ratio conversion unit 11a. Is changed, the series of processes is terminated, and the process returns to the original process.
On the other hand, in step S508, if there is no nozzle of the same color as the selected nozzle color and the process proceeds to step S514, the same processing as in step S216 in the first embodiment is performed based on the color ratio information, and a series of steps is performed. End the process and return to the original process.

Next, the operation of the present embodiment will be described with reference to FIG.
Here, FIG. 17 is a diagram illustrating an example of a color ratio conversion process when a nozzle corresponding to light cyan is involved in banding.
In the present embodiment, although not shown in the figure, the dot pattern formed by the light cyan nozzle causes “white streaks” and “white streaks” due to the flight curve of the nozzle as in FIG. 8B in the first embodiment. It is assumed that “dark streaks” are generated.

  The generation process of the second image data in the present embodiment is started by acquiring the CMYK image data transmitted from the image data acquisition unit 10 in the color ratio conversion unit 11a (step S400). CMYK of the CMYK image data is color-divided into a total of six colors, CMYK and LC and LM, to generate second CMYK image data (step S402). Next, nozzle information is read from the nozzle information storage unit 11b, and the read nozzle information is stored in a predetermined area of the RAM 62 (step S404).

  When the color ratio conversion unit 11a acquires the nozzle information, the second image data generation process is not processed from the nozzle information corresponding to the nozzle modules corresponding to the CMYK, LC, and LM inks from the nozzle information. One nozzle information corresponding to the nozzle module is selected (step S406). In the present embodiment, the nozzle information is the same as the data table shown in FIG. 10A in the first embodiment.

  Further, when the color ratio conversion unit 11a selects the data table for the selected nozzle module, the color ratio conversion unit 11a then selects an unprocessed nozzle number in the data table (step S408), and the relative flight of each table corresponding to the selected nozzle number. Based on the information indicating the amount of bending, it is determined whether or not the selected nozzle is involved in banding (step S410). Here, in the present embodiment, as in the first embodiment, when the relative flight bending amount of the selected nozzle is equal to or larger than a preset threshold (for example, 4 [μm]), It is determined that the selected nozzle is involved in banding (“Yes” branch of step S410), and if the selected nozzle is normally discharged and the relative flight bending amount of the selected nozzle is smaller than the threshold value, it is determined that the selected nozzle is not involved in banding. ("No" branch in step S410).

  Hereinafter, processing when it is determined that the selected nozzle is involved in banding will be described. When the selected nozzle is involved in banding, the color ratio conversion unit 11a first selects pixel data related to the selected nozzle from the first image data (step S412), and then the color of the ink ejected by the selected nozzle. In step S500, it is determined whether there is a nozzle corresponding to the same color ink. Here, if the selected nozzle is a light cyan nozzle, there is a cyan nozzle as a nozzle of the same color as the light cyan nozzle (branch “Yes” in step S500). Therefore, based on the color ratio information, the ink discharge amount of the light cyan ink is The pixel value of the pixel data corresponding to the selected nozzle (light cyan nozzle) is changed so that the ejection ratio can avoid or reduce banding.

For example, the cyan ink ejection ratio of pixel data corresponding to abnormal nozzles including the selected nozzle in CMYK image data is 75 (%) as shown in FIG. 17, and 75% of this cyan ink is divided by color division. Suppose that 30% is divided by the cyan nozzle and 45% is handled by the light cyan nozzle. Here, in this embodiment, it is assumed that the density of both can be made the same by ejecting 20% of light cyan ink to 10% of cyan ink. That is, the light cyan density and the cyan density have a ratio of 1: 2. Accordingly, as shown in FIG. 17, after the color division, the discharge ratio of cyan ink is 30%, and the remaining 45% of cyan ink is handled by light cyan ink. Therefore, the discharge ratio of light cyan ink is 45 (% ) × 2 = 90% However, as described above, since the selected nozzle (light cyan nozzle) is a nozzle involved in banding, the color ratio conversion unit 11a performs the light cyan ink ejection ratio 90 based on the color ratio information. As shown in FIG. 17, the pixel value of the pixel data of the abnormal nozzles including the selected nozzle is changed so that% becomes 40% that can avoid or reduce banding (step S504). Here, in the present embodiment, the color ratio information includes the maximum discharge ratios for LC and LM in addition to the maximum discharge ratios corresponding to CMYK in the first embodiment. In the present embodiment, banding can be avoided or reduced by reducing the light cyan ink ejection ratio to 40%.

  Then, as shown in FIG. 17, the discharge amount of the light cyan ink corresponding to the selected nozzle is reduced by 50% from 90% to 40%, and the discharge amount of cyan ink is changed from 30% to 55%, as shown in FIG. The pixel value of the pixel data corresponding to the cyan ink nozzle corresponding to the abnormal nozzle including the selected nozzle is changed so as to increase by 25% (50 (%) / 2), thereby compensating for the same color range. (Step S506). In other words, the decrease in light cyan ink is compensated by increasing the ink discharge amount of cyan ink, and the original color composed of multiple colors including abnormal nozzles before changing the light cyan ink discharge ratio is the same color. To be in the range.

  Further, from the above-described ratio relationship, if cyan and light cyan represent the same density and have the same dot size, the number of dots formed (printing ratio) for light cyan is twice that for cyan. Therefore, in the color ratio conversion process described above, since light cyan is replaced with 50% of cyan, graininess may be deteriorated. Therefore, integration with other colors is performed to reduce the deterioration of graininess (step) “Yes” branch of S508). In the present embodiment, as shown in FIG. 17, the reduction in the number of dots is alleviated by allocating the 10% discharge ratio of cyan ink to the discharge ratio of nozzles corresponding to other colors whose density is lower than that of cyan ink. is doing.

In the above example, the case where the light cyan ink nozzle is involved in banding has been described. However, when the cyan ink nozzle is involved in banding, contrary to the case of light cyan, the cyan can be avoided or reduced at a rate at which banding can be avoided or reduced. The ink discharge rate is decreased, and this decrease is compensated by increasing the light cyan ink discharge amount. In this case, the number of light cyan ink dots formed may increase too much, or the light cyan density may not be sufficient. In such cases, integration with other colors will be attempted, and ink ejection of other colors will occur. Take action by changing the ratio.
Magenta and light magenta can also perform color ratio conversion processing based on the same principle as the above-described cyan and light cyan.

  In the above example, the light cyan ink discharge ratio is finally 40%. However, if the light cyan ink discharge ratio related to this banding can be reduced to 25% or less, As in the first embodiment, since it is possible to configure a color even when the printing resolution of the light cyan nozzle is ½, a nozzle that causes banding, that is, a nozzle that is defective in ejection, or a light cyan that generates a flight curve. The nozzle itself can be disabled. In such a case, as in the first embodiment, information indicating that the nozzle is not used for the pixel data corresponding to the nozzle that causes banding in the light cyan nozzle module (no dot is formed). Information to make the print resolution halved in the N-ary processing unit 12 with respect to the pixel data corresponding to the abnormal nozzle.

  For the nozzles that have been subjected to the above-described determination processing for all the nozzles of all the nozzle modules of the print head 200 and have been determined to be involved in banding, the abnormal nozzle including the nozzle and the abnormal nozzle in the second CMYK image data By performing a process of changing the pixel value of the pixel data corresponding to the nozzle related to the color mixture ratio so that the color mixing ratio can avoid or reduce banding and is in the same color range as the color before the change, Second image data is generated. Then, the generated second image data is transmitted to the print data generating unit 12, and the print data generating unit 12 executes a print data generating process (step S106).

  As described above, when the ink ejection ratio of abnormal nozzles including nozzles involved in banding is changed to an ejection amount that can avoid or reduce banding, the amount reduced by this change is the same color ink as the abnormal nozzle. It is possible to compensate by changing the ink ejection ratio of the nozzles corresponding to, and further, it is possible to integrate with other colors as well as similar colors, so the color changes by compensating with similar colors It is possible to reduce the occurrence of problems such as the occurrence of problems, and it is possible to prevent deterioration of graininess by integrating with other colors, and since the selection range of the color mixture ratio is widened, the color ratio more effective for banding The second image data subjected to the conversion process can be generated.

  In the second embodiment, the image data acquisition unit 10 corresponds to the image data acquisition unit of mode 1 or 28, and the second image data generation unit 11 includes modes 1, 2, 7, 28, 29, and 34. The print data generation unit 12 corresponds to any one of the first, eighth, 28, and 35 print data generation units, and the print unit 13 corresponds to any one of the second image data generation units. This corresponds to the printing means of the first form.

  In the second embodiment, step S102 corresponds to the image data acquisition step of any one of modes 11, 20, 36, and 45, and step S104 is mode 11, 12, 17, 20, 21, 26. , 36, 37, 42, 45, 46 and 51, corresponding to any one of the second image data generation steps, step S106 is one of the forms 11, 18, 20, 27, 36, 43, 45 and 52. Step S110 corresponds to the printing step of Form 11 or 20, corresponding to one printing data generation step.

  Also, the printing apparatus according to the first and second embodiments is characterized in that printing data is generated from image data in accordance with the characteristics of the print head with almost no modification to the existing printing apparatus itself. Therefore, it is not necessary to prepare a special printer as the printing unit 13, and an existing inkjet printer can be used as it is. Further, if the printing unit 13 is separated from the printing apparatus 100 in the first to third embodiments, the function can be realized only by a general-purpose print instruction terminal (printing data generation apparatus) such as a PC. Become.

Further, the present invention is not limited to the flying bend phenomenon, but the ink ejection direction is vertical (normal), but the formation content of the nozzle is deviated from the normal position. As a result, the dots formed are the same as the flying bend phenomenon. Of course, the present invention can be applied in exactly the same manner.
The printing apparatus 100 in the first to third embodiments can be applied not only to a line head type ink jet printer but also to a multi-pass type ink jet printer. It is possible to obtain high-quality printed material with almost no noticeable white or dark streaks in one pass even if the flight bend phenomenon occurs. Since it can be reduced, high-speed printing is possible than before.

FIGS. 18A to 18C show respective printing systems using a line head type ink jet printer and a multi-pass type ink jet printer.
As shown in FIG. 4A, when the width direction of the rectangular printing paper S is the main scanning direction of the image data and the longitudinal direction is the sub-scanning direction of the image data, the line head type inkjet printer As shown in (B), the print head 200 has a length corresponding to the paper width of the print paper S, the print head 200 is fixed, and the print paper S is sub-scanned with respect to the print head 200. The printing is completed in one pass (operation) by moving in the direction. Note that it is also possible to perform printing while fixing the printing paper S and moving the print head 200 side in the sub-scanning direction, or moving both in the opposite direction as in a so-called flat head type scanner. . On the other hand, in the multi-pass type ink jet printer, as shown in FIG. 5C, the print head 200, which is much shorter than the paper width, is positioned in the direction perpendicular to the main scanning direction. Printing is executed by moving the printing paper S in the sub-scanning direction by a predetermined pitch while reciprocating in the main scanning direction many times. Therefore, the latter multi-pass type ink jet printer has a drawback that it takes more printing time than the former line head type ink jet printer, but the print head 200 can be repeatedly positioned at an arbitrary position. Among the banding as described above, it is possible to cope to some extent with respect to the reduction of the white streak phenomenon.

In the first and second embodiments, the ink jet printer that performs printing by ejecting ink in the form of dots has been described as an example. However, the present invention provides a print head in which the print mechanisms are arranged in a line. The present invention can also be applied to other printing apparatuses used, for example, thermal head printers called thermal transfer printers or thermal printers.
In FIG. 3, each nozzle module 50, 52, 54, 56 provided for each color of the print head 200 has a form in which the nozzles N are linearly continuous in the longitudinal direction of the print head 200. As shown in FIG. 19, each of these nozzle modules 50, 52, 54, 56 is composed of a plurality of short nozzle units 50a, 50b,... 50n, which are arranged before and after the movement direction of the print head 200. You may comprise as follows. In particular, if each nozzle module 50, 52, 54, 56 is configured with a plurality of short nozzle units 50a, 50b,... 50n, the individual lengths of the nozzle units 50a, 50b,. Since it is possible to configure a long nozzle module using the above-described head, it is possible to increase the manufacturing yield of the nozzle module.

1 is a block diagram illustrating a configuration of a printing apparatus 100 according to the present invention. It is a figure which shows the hardware constitutions of a computer system. It is a partial expanded bottom view which shows the structure of the print head 200 of this invention. FIG. 5 is a partially enlarged side view of FIG. 4. 3 is a flowchart illustrating a printing process in the printing apparatus 100. 6 is a flowchart illustrating a second image data generation process in the second image data generation unit 11 of the printing apparatus 100 according to the first embodiment. 4 is a flowchart illustrating print data generation processing in the print data generation unit 12 of the printing apparatus 100. (A) is the figure which showed an example of the dot pattern formed by the cyan nozzle module 56 without the abnormal nozzle which generate | occur | produces what is called a flight curve, (b) is a nozzle N6 among the cyan nozzle modules 56 flying. It is the figure which showed an example of the dot pattern formed when the curve phenomenon has generate | occur | produced. (A) is a figure which shows the dot pattern which made the nozzle N6 in the cyan nozzle module 56 unusable, and was formed with the resolution 1/2, (b) is an abnormal nozzle including the nozzle N6 in the cyan nozzle module 56. It is a figure which shows an example of the dot pattern formed by reducing the amount of ink discharge. (A) is a figure which shows the information table which shows the presence or absence of the ink non-ejection of each nozzle contained in nozzle information, (b) is a figure which shows the information table which shows the relative flight bending amount of each nozzle. (A) is a figure which shows an example of the image before a color ratio change formed by the nozzle corresponding to each color of CMYK including an abnormal nozzle, (b) is an image after color ratio conversion of (a). FIG. It is a figure which shows the information table which shows the banding avoidable mixing ratio for every color contained in color ratio information. It is a figure which shows an example of the information of N value with respect to dot size, and the information of the threshold value with respect to each N value. It is a figure which shows an example of the error diffusion matrix used for a N-value-izing process. 12 is a flowchart illustrating second image data generation processing in the second image data generation unit 11 of the printing apparatus 100 according to the second embodiment. 6 is a flowchart illustrating a color ratio conversion process focusing on light cyan in the second image data generation unit 11 of the printing apparatus 100. It is a figure which shows an example of the color ratio conversion process course in case the nozzle corresponding to light cyan is concerned with banding. (A)-(C) is explanatory drawing which shows the difference in the printing system by a multipass type inkjet printer and a line head type inkjet printer. It is a conceptual diagram which shows the other example of the structure of a print head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Printing apparatus, 200 ... Print head, 10 ... Image data acquisition part, 11 ... 2nd image data generation part, 11a ... Color ratio conversion part, 11b ... Nozzle information storage part, 11c ... Color ratio information storage part, 12 ... Print data generation unit, 12a... N-value processing unit, 12b... N-value information storage unit, 13... Print unit, 60... CPU, 62. ... Output device, 74 ... Input device, 50 ... Black nozzle module, 52 ... Yellow nozzle module, 54 ... Magenta nozzle module, 56 ... Cyan nozzle module, P, S ... Print medium (paper), L ... Network cable, N ... nozzle

Claims (15)

A printing apparatus capable of forming dots on a medium used for printing and printing a color image to be printed on the medium by a print head having a plurality of nozzles corresponding to a plurality of colors of ink,
Image data acquisition means for acquiring first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to each color of the color image;
Nozzle information storage means for storing nozzle information capable of identifying nozzles involved in banding in the plurality of nozzles;
Second image data generating means for generating second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in banding in the first image data based on the nozzle information;
Print data generated by converting the second image data into dot formation pattern data corresponding to each color of the color image for forming a color image composed of the second image data on the medium. Printing data generation means for
Printing means for printing a color image constituted by the second image data by the print head on the medium based on the printing data;
The second image data generation means applies the abnormal nozzle to an image portion of a predetermined color printed by a nozzle corresponding to a plurality of colors including the abnormal nozzle in a color image constituted by the first image data. The pixel value of the pixel data corresponding to is changed to a value that avoids or reduces the banding, and after the change, the image portion of the predetermined color is printed so that the predetermined color falls within the same color range. A printing apparatus, wherein the pixel value of pixel data corresponding to a nozzle having a color different from the color of ink ejected by the abnormal nozzle is changed.   The second image data generation means changes the pixel value of the pixel data corresponding to the abnormal nozzle to a value that reduces the ink discharge amount of the abnormal nozzle from the discharge amount before the change, and the image portion of the predetermined color The pixel value of the pixel data corresponding to the nozzle of the other color different from the color of the abnormal nozzle related to the printing is decreased at the abnormal nozzle from the ejection amount before changing the ink discharge amount of the nozzle of the other color The printing apparatus according to claim 1, wherein the second image data in which the predetermined color is in the same color range is generated by changing to a value that compensates for the amount of ink ejected.   The same color range is a range in which the color difference ΔE between the image part before changing the pixel value and the image part after changing the pixel value is “0 ≦ ΔE ≦ 0.7” in the Lab color space. The printing apparatus according to claim 1, wherein the printing apparatus is a printer.   4. The color different from the color of ink ejected by the abnormal nozzle is a different color from the color of ink ejected by the abnormal nozzle. The printing apparatus according to item.   The color other than the color of the ink ejected by the abnormal nozzle is a color of the same system as the color of the ink ejected by the abnormal nozzle. The printing device according to item.   The other colors different from the color of the ink discharged from the abnormal nozzle include both the same color and the different color of the ink discharged from the abnormal nozzle. Item 4. The printing device according to any one of Items 3 to 3.   The said 2nd image data production | generation means determines the change value of the pixel value corresponding to the said abnormal nozzle based on the color corresponding to the said abnormal nozzle, The any one of Claim 1 thru | or 6 characterized by the above-mentioned. The printing apparatus as described in.   The printing data generation unit is configured to generate pixel data for pixel data having a pixel value with an ink ejection amount equal to or less than a predetermined amount among pixel data corresponding to nozzles involved in banding in the second image data. The printing apparatus according to claim 1, wherein printing data is generated so that dots are not formed on a part or all of the printing apparatus.   2. The print head according to claim 1, wherein the nozzles are continuously arranged over a range wider than a mounting area of the print medium, and the print head can be printed by one scan. Item 9. The printing apparatus according to any one of items 8 to 9.   The printing according to any one of claims 1 to 8, wherein the printing head is a printing head that performs printing while reciprocating in a direction orthogonal to a paper feeding direction of the printing medium. apparatus. Used to control a printing apparatus that prints a color image to be printed on a medium by a print head that can form dots on the medium used for printing and has a plurality of nozzles corresponding to inks of a plurality of colors. A printing device control program,
An image data acquisition step of acquiring first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to each color of the color image;
Second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in banding in the first image data based on nozzle information that can identify nozzles involved in banding among the plurality of nozzles. A second image data generation step for generating
Print data generated by converting the second image data into dot formation pattern data corresponding to each color of the color image for forming a color image composed of the second image data on the medium. A data generation step for printing,
A program used for causing a computer to execute a process including a printing step of printing a color image constituted by the second image data on the medium by the print head based on the printing data;
In the second image data generation step, the abnormal image portion of the predetermined color that is printed by the nozzles corresponding to a plurality of colors including the abnormal nozzles in the color image constituted by the first image data. The pixel value of the pixel data corresponding to the nozzle is changed to a value that avoids or reduces the banding, and after the change, the image portion of the predetermined color is printed so that the predetermined color is in the same color range. A printing apparatus control program that changes a pixel value of pixel data corresponding to a nozzle having a color different from the color of ink ejected by the abnormal nozzle. Used to control a printing apparatus that prints a color image to be printed on a medium by a print head that can form dots on the medium used for printing and has a plurality of nozzles corresponding to inks of a plurality of colors. A printing apparatus control method comprising:
An image data acquisition step of acquiring first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to each color of the color image;
Second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in banding in the first image data based on nozzle information that can identify nozzles involved in banding among the plurality of nozzles. A second image data generation step for generating
Print data generated by converting the second image data into dot formation pattern data corresponding to each color of the color image for forming a color image composed of the second image data on the medium. A data generation step for printing,
A program used for causing a computer to execute a process including a printing step of printing a color image constituted by the second image data on the medium by the print head based on the printing data;
In the second image data generation step, the abnormality is applied to the image portion of the predetermined color that is printed by the nozzles corresponding to a plurality of colors including the abnormal nozzle in the color image constituted by the first image data. The pixel value of the pixel data corresponding to the nozzle is changed to a value that avoids or reduces the banding, and after the change, the image portion of the predetermined color is printed so that the predetermined color is in the same color range. A printing apparatus control method, comprising: changing a pixel value of pixel data corresponding to a nozzle having a color different from a color of ink ejected by the abnormal nozzle. Printing data used in a printing apparatus that prints a color image to be printed on the medium by a print head that can form dots on a medium used for printing and has a plurality of nozzles corresponding to a plurality of colors of ink. A print data generation device for generating
Image data acquisition means for acquiring first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to each color of the color image;
Nozzle information storage means for storing nozzle information capable of identifying nozzles involved in banding in the plurality of nozzles;
Second image data generating means for generating second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in banding in the first image data based on the nozzle information;
Print data generated by converting the second image data into dot formation pattern data corresponding to each color of the color image for forming a color image constituted by the second image data on the medium. Printing data generation means for
The second image data generation unit applies an abnormal nozzle to an image portion of a predetermined color printed by a nozzle corresponding to a plurality of colors including the abnormal nozzle in a color image constituted by the first image data. The pixel value of the corresponding pixel data is changed to a value that avoids or reduces the banding, and after the change, the image portion of the predetermined color is printed so that the predetermined color is in the same color range. A printing data generation apparatus, wherein a pixel value of pixel data corresponding to a nozzle of a color different from the color of ink ejected by the abnormal nozzle is changed. Printing data used in a printing apparatus that prints a color image to be printed on the medium by a print head that can form dots on a medium used for printing and has a plurality of nozzles corresponding to a plurality of colors of ink. A print data generation program used to generate
An image data acquisition step of acquiring first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to each color of the color image;
Second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in banding in the first image data based on nozzle information that can identify nozzles involved in banding among the plurality of nozzles. A second image data generation step for generating
Print data generated by converting the second image data into dot formation pattern data corresponding to each color of the color image for forming a color image composed of the second image data on the medium. Including a program used to cause a computer to execute a process consisting of a print data generation step
In the second image data generation step, the abnormal nozzle for an image portion of a predetermined color printed by nozzles corresponding to a plurality of colors including the abnormal nozzle in the color image constituted by the first image data. The pixel value of the pixel data corresponding to is changed to a value that avoids or reduces the banding, and after the change, the image portion of the predetermined color is printed so that the predetermined color falls within the same color range. A printing data generation program for changing a pixel value of pixel data corresponding to a nozzle having a color different from the color of ink ejected by the abnormal nozzle. Printing data used in a printing apparatus that prints a color image to be printed on the medium by a print head that can form dots on a medium used for printing and has a plurality of nozzles corresponding to a plurality of colors of ink. A print data generation method used to generate
An image data acquisition step of acquiring first image data having a plurality of pixel data corresponding to pixel values of M values (M ≧ 2) corresponding to each color of the color image;
Second image data obtained by changing pixel values of pixel data corresponding to abnormal nozzles involved in banding in the first image data based on nozzle information that can identify nozzles involved in banding among the plurality of nozzles. A second image data generation step for generating
Print data generated by converting the second image data into dot formation pattern data corresponding to each color of the color image for forming a color image constituted by the second image data on the medium. Printing data generation step to
In the second image data generation step, the abnormal nozzle for an image portion of a predetermined color printed by nozzles corresponding to a plurality of colors including the abnormal nozzle in the color image constituted by the first image data. The pixel value of the pixel data corresponding to is changed to a value that avoids or reduces the banding, and after the change, the image portion of the predetermined color is printed so that the predetermined color falls within the same color range. A printing data generation method characterized by changing a pixel value of pixel data corresponding to a nozzle having a color different from the color of ink ejected by the abnormal nozzle.

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