JP2012148468A - Printing device and printing method - Google Patents

Abstract

A technique related to a printing apparatus is provided.
A printing apparatus that performs printing upon receiving ink supplied from L ink cartridges that store ink of the same hue, and includes a nozzle row in which a plurality of nozzles that eject ink are arranged in the sub-scanning direction. A plurality of print heads spaced apart in the scanning direction have the same position in the sub-scanning direction of the arranged nozzles of the plurality of nozzle rows, and a predetermined correlation on printing by control from the control unit The L × a row nozzle rows each having an a row include a first nozzle group that receives ink supply from each of the L ink cartridges, and each of the nozzles arranged in the plurality of nozzle rows. The L × b nozzle rows whose positions in the sub-scanning direction are different from the nozzles of the first nozzle group are b second nozzles that receive ink from each of the L ink cartridges. A printing apparatus including a group and determining a use ratio based on the image data.
[Selection] Figure 3

Description

  The present invention relates to a printing apparatus, and more particularly to a printing apparatus and a printing method that perform printing by receiving ink supplied from a plurality of ink cartridges that contain ink of the same hue.

  Conventionally, there has been a demand for suppressing uneven consumption of ink between ink cartridges (hereinafter also referred to as “single reduction”) in a printing apparatus having a plurality of ink cartridges containing ink of the same hue. For example, a technique disclosed in Patent Document 1 is known as a technique for suppressing the decrease in the half.

JP 2009-1113412 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a technique that suppresses a decrease in a plurality of ink cartridges containing ink of the same hue by a method different from the conventional one.

  In order to solve at least a part of the problems described above, the present invention can take the following forms or application examples.

[Application Example 1]
A printing apparatus that performs printing upon receiving ink supplied from L (L is an integer of 2 or more) ink cartridges that store ink of the same hue, wherein a plurality of nozzles that eject the ink are arranged in a predetermined direction A print head having a plurality of nozzle rows spaced apart from each other in a direction intersecting the direction; a separation direction of the nozzle rows as a main scanning direction; an arrangement direction of the nozzles as a sub-scanning direction; And a control unit for controlling both the scanning of the print head by the head moving unit and the ejection of ink from the nozzles. The head has the same position in the sub-scanning direction of the arranged nozzles among the plurality of nozzle rows, and has a predetermined correlation on printing by the control from the control unit. The L × a row nozzle rows (a is an integer equal to or greater than 1) include a first nozzle group that receives the supply of ink from each of the L ink cartridges, and a plurality of the nozzle rows. L × b (b is an integer of 1 or more) nozzle rows in which the positions of the arranged nozzles in the sub-scanning direction are different from the nozzles of the first nozzle group are b And a second nozzle group that receives the supply of ink from each of the L ink cartridges, and the first nozzle based on the number of ink dots determined by halftone processing for image data A printing apparatus that determines which of the nozzle rows belonging to the first nozzle group forms an ink dot formed by ink ejected by a nozzle row belonging to the group.
According to this printing apparatus, even when the positions of the ink dots to be formed are deviated on the image data, it is possible to suppress uneven consumption (half reduction) of the ink stored in the plurality of ink cartridges.

[Application Example 2]
The printing apparatus according to the above, wherein the number of ink dots determined by the halftone process on the image data is the number of ink dots formed by the ink ejected by the nozzle row belonging to the first nozzle group. apparatus.
According to this printing apparatus, in determining which of the nozzle rows belonging to the first nozzle group the ink dots formed by the ink ejected from the nozzle row belonging to the first nozzle group are formed, the second nozzle It is not necessary to be based on the region formed by the ink ejected by the nozzle rows belonging to the group, and the processing can be simplified.

[Application Example 3]
The printing apparatus according to the above, wherein the ink dots formed by the ink ejected from the nozzle rows belonging to the first nozzle group are sequentially formed one pixel at a time from each of the L ink cartridges.

  According to this printing apparatus, even when the positions of the ink dots to be formed are deviated on the image data, the difference in the amount of ink formed by each nozzle row of the first nozzle group is 1 between the L ink cartridges. It is possible to make it within the dots, and therefore, it is possible to further suppress the reduction of the half.

[Application Example 4]
In the printing apparatus described above, the number of ink dots determined by the halftone process on the image data is the number of ink dots formed by the ink ejected from the nozzle row belonging to the second nozzle group, Ink ejected by the nozzle row belonging to the first nozzle group based on the ratio of each of the L ink cartridges to the number of ink dots formed by the ink ejected by the nozzle row belonging to the second nozzle group A printing apparatus for determining a ratio of each of the L ink cartridges in the number of ink dots formed by

  According to this printing apparatus, even when the positions of the ink dots formed by the nozzle rows belonging to the second nozzle group are biased on the image data, the usage ratio of the nozzle rows belonging to the first nozzle group is changed. It is possible to further suppress the decrease in the amount.

[Application Example 5]
The printing apparatus as described above, wherein L = 2, a = 1, and b = 1.
According to this printing apparatus, the print head can be downsized.

[Application Example 6]
A printing method of a printing apparatus that performs printing by receiving ink supplied from L (L is an integer of 2 or more) ink cartridges containing ink of the same hue, the printing apparatus ejecting the ink A print head having a plurality of nozzle rows arranged in a predetermined direction spaced apart from each other in a direction intersecting the direction, a separation direction of the nozzle rows as a main scanning direction, and an arrangement direction of the nozzles as a sub scanning direction A head moving unit that moves the print head in both scanning directions relative to the print medium, and controls both the scanning of the print head by the head moving unit and ejection of ink from the nozzles. The print head includes a plurality of nozzle rows in which the arranged nozzles have the same position in the sub-scanning direction and are controlled by the control unit. The L × a row (a is an integer of 1 or more) nozzle row having a predetermined correlation in printing is a first nozzle that receives the ink supply from each of the L ink cartridges by a row. Among the plurality of nozzle rows of the group and the plurality of nozzle rows, the positions of the arranged nozzles in the sub-scanning direction are different from the nozzles of the first nozzle group by L × b (b is an integer of 1 or more ) Nozzle arrays each including the b nozzle groups and the second nozzle group that receives the ink supply from each of the L ink cartridges, and (a) ink determined by halftone processing on image data The number of dots is obtained. (B) Based on the number of ink dots determined by the halftone process on the image data, the ink ejected by the nozzle rows belonging to the first nozzle group The ink dots formed Te, printing method for determining whether to form any of the nozzle rows belonging to the first nozzle group.

  By performing printing with a printing apparatus using this printing method, it is possible to suppress a reduction in the amount.

  Note that the present invention can be realized in various modes. For example, the present invention can be realized in the form of a method and an apparatus for suppressing one-side reduction, a printing system, an integrated circuit for realizing the functions of the method or apparatus, a computer program, a recording medium on which the computer program is recorded, and the like.

It is explanatory drawing explaining the structure of the printing apparatus as 1st Example. It is explanatory drawing which shows typically the structure of the print head in a printing apparatus. It is explanatory drawing explaining the mechanism of the supply of ink. 6 is a flowchart illustrating a flow of printing processing performed by the printing apparatus. It is explanatory drawing explaining the table M2 for discharge nozzle determination. It is explanatory drawing explaining matrix MT1. It is explanatory drawing explaining the effect in 1st Example. It is explanatory drawing explaining matrix MT2 in the modification 1. FIG. It is explanatory drawing explaining the aspect 1 in the modification 2. FIG. It is explanatory drawing explaining the aspect 2 in the modification 2. FIG. It is explanatory drawing explaining the aspect 3 in the modification 2. FIG.

Next, embodiments of the present invention will be described based on examples.
A. First embodiment:
(A1) Configuration of printing apparatus:
FIG. 1 is an explanatory diagram illustrating a configuration of a printing apparatus 10 as a first embodiment. The printing apparatus 10 is an ink jet printer that prints characters, images, and the like by ejecting ink onto a print medium P based on image data. In the present embodiment, the printing apparatus 10 has various functions such as a scanner and a copy as a so-called multifunction machine. Further, as will be described later, the printing apparatus 10 is a printing apparatus dedicated to monochrome printing that performs printing using only black ink.

  The printing apparatus 10 includes a card slot 12 and a communication connector 13. The card slot 12 of the printing apparatus 10 is an interface that is connected so as to be able to exchange data with a memory card containing a storage medium. The communication connector 13 of the printing apparatus 10 is an interface that is connected to an external device such as a personal computer, a digital camera, or a digital video camera so as to exchange data. The printing apparatus 10 is stored in a memory card connected to the card slot 12 or an external device connected to the communication connector 13 in addition to a function of printing based on a print request from an external device connected to the communication connector 13. It has a function of printing existing image data.

  The printing apparatus 10 further includes a scanner unit 11, a display 14, and an operation panel 15. The scanner unit 11 reads a document placed on a document table and converts it into digital data. The display 14 displays characters and images for the user. The operation panel 15 receives an instruction input from the user.

  In addition to the card slot 12 and the communication connector 13 described above, the printing apparatus 10 further includes a control unit 20 that controls each unit of the printing apparatus 10 and a printing mechanism unit 30 that executes printing on the printing medium P. .

  The control unit 20 includes a CPU 21, a RAM 22, and a ROM 23. The CPU 21 includes an image data acquisition unit 24, a monochrome conversion unit 25, a halftone processing unit 26, an ejection nozzle determination processing unit 27, and a print control unit 28. The image data acquisition unit 24 acquires image data from the scanner unit 11, the card slot 12, and the communication connector 13. The monochrome conversion unit 25 performs data conversion to monochrome image data when the acquired image data is RGB image data. The halftone processing unit 26 performs a process of converting the image data into a distribution of dots based on the gradation of the image data subjected to the monochrome conversion. The dither mask M1 stored in the ROM 23 is used for the halftone process. The discharge nozzle determination processing unit 27 discharges ink from which nozzles of the print head 50 described later to each dot of the image data after the halftone process, using the discharge nozzle determination table M2 stored in the ROM 23. To determine whether to form dots on the print medium P. The print control unit 28 controls the operation of the printing mechanism unit 30 based on the data after processing by the ejection nozzle determination processing unit 27. Each process described above is realized by the CPU 21 reading and executing a program stored in the ROM 23. The dither mask M1 and the ejection nozzle determination table M2 are stored in the ROM 23 in advance.

  As shown in FIG. 1, the printing mechanism unit 30 of the printing apparatus 10 includes a carriage 40, a head unit 41, a carriage drive unit 32, and a transport unit 34. The carriage drive unit 32 drives the carriage 40 in the main scanning (head scanning) direction. The transport unit 34 transports the print medium P in the sub-scanning direction that intersects the main scanning direction in which the carriage 40 moves.

  The carriage 40 holds the head unit 41 and mounts the ink cartridge 42 and the ink cartridge 43. The ink cartridges 42 and 43 mounted on the carriage 40 function as a liquid supply unit that supplies ink to the head unit 41. Both of the ink cartridges 42 and 43 contain black (BK) ink. In the present embodiment, black and white printing is performed as monochrome printing. For example, the ink cartridges 42 and 43 are, for example, sepia, red, blue, magenta (M), cyan (C), or the like. It is also possible to print a single color such as magenta or cyan. Alternatively, the ink cartridge 42 may contain black (BK), the ink cartridge 43 contains light black (LK), and the like.

  The head unit 41 includes a print head 50. The print head 50 includes a plurality of nozzles that eject black (BK) ink. Printing on the print medium P is realized by the print head 50, the carriage drive unit 32, and the transport unit 34 cooperating under the control of the control unit 20.

  FIG. 2 is an explanatory diagram schematically showing the configuration of the print head 50 in the printing apparatus 10. The print head 50 includes a plurality of nozzle rows in which a plurality of nozzles NZ that eject ink (black in this embodiment) are arranged in the sub-scanning direction (that is, the paper feed direction).

  In the present embodiment, the print head 50 includes four nozzle rows of A row, B row, C row, and D row in which a plurality of nozzles NZ are arranged in the sub-scanning direction (that is, the paper feeding direction). These four nozzle rows are arranged in parallel in the main scanning direction as shown in FIG. The A row and the B row are arranged with an interval of 40/360 [inch] in the main scanning direction. Similarly, the C row and the D row are also arranged with an interval of 40/360 [inch] in the main scanning direction. The B row and the C row are arranged with an interval of 104/360 [inch].

  In each of the nozzle rows A, B, C, and D, 128 nozzles NZ are arranged in the sub-scanning direction. In each nozzle row, the interval in the sub-scanning direction between the nozzles NZ (hereinafter also referred to as “nozzle pitch”) is 1/120 [inch]. The position of row B in the print head 50 is arranged at a position shifted by 1/360 [inch] in the sub-scanning direction with reference to the nozzle row of row A. The position of the C row in the print head 50 is arranged at a position shifted by 1/360 [inch] in the sub scanning direction with reference to the nozzle row of the B row. The position of the D row in the print head 50 is arranged at the same position as the nozzle row of the C row in the sub-scanning direction. Accordingly, by performing printing by scanning the print head 50 in the main scanning direction, printing is substantially performed in the same manner as a print head having a nozzle pitch of 1/360 [inch]. The nozzle rows of the C row and the D row correspond to the first nozzle group described in the claims, and the nozzle rows of the A row and the B row correspond to the second nozzle group described in the claims. To do.

  Each of the plurality of nozzles NZ includes a piezo element (piezoelectric element), and ejects ink from the nozzle NZ by vibration due to distortion of the piezo element accompanying application of a voltage to the piezo element. Accordingly, each nozzle NZ includes an electrode for applying a voltage and other elements necessary for ejecting ink in addition to the above-described piezoelectric element. In the present embodiment, when the print head 50 is manufactured, the nozzle unit 52 including the nozzle rows of the A row and the B row and the nozzle unit 53 including the nozzle rows of the C row and the D row are manufactured, respectively. The unit 52 and the nozzle unit 53 are incorporated in the main body of the print head 50.

  Specifically, the nozzle unit 52 (or nozzle unit 53) is manufactured using a substrate having a through hole at the position of each nozzle NZ in the A row and B row (or C row and D row). When manufacturing the nozzle unit, a substrate material capable of cutting out a plurality of substrates used for the nozzle unit is used. A through-hole serving as a nozzle is opened at each position of the substrate material serving as each nozzle unit, and a piezoelectric element is attached to each through-hole or electrode printing is performed. And a nozzle unit is manufactured by cutting out the board | substrate material after passing through these processes as each nozzle unit. That is, in the case of the present embodiment, the nozzles NZ included in the A row and the B row are manufactured in the same series of manufacturing steps. Similarly, the nozzles NZ included in the C row and the D row are manufactured in the same series of manufacturing steps. In other words, the nozzle unit is common to the A row and the B row, and the nozzle unit is common to the C row and the D row.

  Next, a mechanism for supplying ink from the ink cartridges 42 and 43 to each nozzle NZ will be described with reference to FIG. The ink cartridge 42 supplies ink to the nozzles NZ in the A row and the nozzles NZ in the C row. The ink cartridge 43 supplies ink to the nozzles NZ in the B row and the nozzles NZ in the D row. That is, ink is supplied from one ink cartridge to each of the two nozzle units 52 and 53 provided in the print head 50. In other words, each nozzle unit receives ink supply to each one nozzle row for each ink cartridge. Specifically, as shown in FIG. 3, the nozzle unit 52 receives ink supply from the ink cartridge 42 to one row of nozzle rows A, and from the ink cartridge 43 to one row of nozzle rows B. Is receiving ink supply. Therefore, the ink supply is not limited to the ink supply mode according to the present embodiment. For example, the ink cartridge 42 supplies ink to the nozzle NZ of the B row and the nozzle NZ of the C row, and the ink cartridge 43 corresponds to the nozzles NZ and D of the A row. It is good also as an aspect which supplies ink to the nozzle NZ.

(A2) Printing process:
Next, a printing process performed by the printing apparatus 10 will be described. FIG. 4 is a flowchart showing the flow of printing processing performed by the printing apparatus 10. When the printing process is started, the CPU 21 acquires image data through the scanner unit 11, the card slot 12, or the communication connector 13 (step S102). If the acquired image data is RGB image data, the image data is converted into monochrome image data (step S104). For example, the image data is converted into monochrome image data by converting it into a K (black) tone value using a color conversion three-dimensional lookup table composed of R, G, and B elements.

  After conversion to monochrome image data, the CPU 21 performs halftone processing on the monochrome image data (step S106). Specifically, the dither mask M1 stored in the ROM 23 is used to convert the gradation value of each pixel of the monochrome image data into binary data. That is, gradation data is converted into dot data by determining whether or not to form a dot for each pixel of the image data. In this embodiment, a systematic dither method known as halftone processing is used. As the halftone process, in addition to the systematic dither method, other halftone techniques such as an error diffusion method and a density pattern method can be used. Since these halftone techniques are well-known techniques, description thereof will be omitted.

  Thereafter, the CPU 21 performs a discharge nozzle determination process on the image data after the halftone process (step S108). As described above, the ejection nozzle determination process is a process for determining from which nozzle ink is ejected to form dots on the print medium for each dot of the dot data after the halftone process. When performing the discharge nozzle determination process, the CPU 21 uses the discharge nozzle determination table M <b> 2 stored in the ROM 23. Hereinafter, the discharge nozzle determination table M2 will be described.

  FIG. 5 is an explanatory diagram for explaining the ejection nozzle determination table M2. FIG. 5 shows the print head 50 and the ejection nozzle determination table M2. Each square of the matrix of the ejection nozzle determination table M2 corresponds to each pixel of the image data. The alphabets A, B, C, and D described in each square indicate which nozzle row (see FIG. 2) the ink is ejected from. For example, the dots on the dot data corresponding to the squares in which “A” is described are printed by ejecting ink from the nozzles in the A row. In the case where “C, D” is written in one square, printing is performed by ejecting ink from nozzles belonging to either the C row or the D row.

  In the printing process in this embodiment, each raster line in the print image is printed by one main scan of the print head 50. For example, the raster line R1 shown in the ejection nozzle determination table M2 in FIG. 5 in which the squares marked with “A” are arranged in the main scanning direction is drawn from the nozzles NZ1 belonging to the A column shown in the print head 50. Ink dots are formed on the print medium P by one main scan of the print head 50 (hereinafter, the main scan in the print processing of the print head is also referred to as “pass”). On the other hand, the raster line R2 shown in the ejection nozzle determination table M2 in which squares labeled “C, D” are arranged in the main scanning direction is the nozzle NZ2 belonging to the C row and the D row shown in the print head 50. Alternatively, ink is ejected from either one of the nozzles NZ3, and ink dots are formed on the print medium in one pass of the print head 50.

In the present embodiment, for the raster line R2 in which squares described as “C, D” are arranged, only the pixels determined to form dots in the image data after halftone processing are arranged in the C and D columns. Ink is alternately ejected from the nozzle NZ2 or nozzle NZ3 to which the ink belongs, and ink dots are formed on the print medium in one pass of the print head 50. Accordingly, since the nozzle row to be used is determined based on the pixels that actually form dots, for each raster line R2, ink dots ejected from the C nozzle row and ink dots ejected from the D nozzle row And the number difference can be suppressed within one.
FIG. 6 shows an example in which “C” and “D” are alternately arranged for each pixel in the dot forming pixel for the image data after the halftone process. In FIG. 6, the cells corresponding to “C” are hatched to make it easy to visually recognize the arrangement of “C” and “D”. The squares where no image data exists are filled. As shown in FIG. 6, in the matrix MT1, “C” and “D” are alternately arranged in pixels based on the image data. The arrangement of “C” and “D” shown in the matrix MT1 is the nozzle allocation for the actual pixel data, and such allocation has the following three characteristics.

Characteristic (1): Both “C” and “D” may exist in each raster line in the matrix MT1.
Characteristic (2): In the entire matrix MT1, the number of “C” and the number of “D” are the same or substantially the same.
Characteristic (3): In each raster line in the matrix MT1, the number of “C” and the number of “D” are the same or substantially the same.

  Thereafter, the CPU 21 starts printing based on the image data after the discharge nozzle determination process (step S110). When printing is started, the CPU 21 controls the print mechanism unit 30 as a process of the print control unit 28 based on the image data after the discharge nozzle determination processing, such as scanning of the print head 50 and ink discharge from each nozzle NZ. The print image is printed on the print medium P. Then, when the printing of the print image on the print medium P is completed, the CPU 21 ends the printing process.

  As described above, the print head 50 provided in the printing apparatus 10 receives ink supplied from each ink cartridge by the mechanism shown in FIG. That is, each nozzle unit receives ink supply to the same number of nozzle rows for each ink cartridge. Therefore, even when image data based on a general natural image or image data in which gradation deviation exists in the print image area is printed by the printing apparatus 10, it is possible to suppress the ink from being reduced.

  Furthermore, in this embodiment, if the ejection nozzle determination process S108 is performed, the matrix MT1 has the characteristic (2), and the ink stored in the ink cartridge 42 and the ink stored in the ink cartridge 43 are used. It can be consumed substantially evenly. In other words, it is possible to further suppress uneven reduction (half reduction) of ink between the ink cartridges.

  The effect of suppressing this reduction will be specifically described. For example, when the printing process is performed using the ejection nozzle determination table M2, there are approximately the same number of dots based on the A columns and dots based on the B columns. Further, there are approximately the same number of dots based on the C columns and dots based on the D columns. Accordingly, the sum of dots based on the A and C columns and the sum of dots based on the B and D columns are substantially the same in probability in the ejection nozzle determination table M2. Therefore, the ink consumption of the ink cartridge 42 that supplies ink to the nozzles of the A row and the C row and the ink cartridge 43 that supplies ink to the nozzles of the B row and the D row through the printing process in the above embodiment. The quantity is approximately equal in probability.

  As a first effect, the printing apparatus 10 performs the ejection nozzle determination process using the ejection nozzle determination table M2 in the printing process. The discharge nozzle determination table M2 is generated based on the matrix MT1 having the characteristics (1), (2), and (3) described above. The matrix MT in the present embodiment has “characteristic (1): both“ C ”and“ D ”may exist in each raster line in the matrix MT1” ”. Accordingly, even if the print head 50 is installed in the printing apparatus 10 in a state where it is inclined by a manufacturing process or some external action after the manufacture, the dot arrangement generated due to the inclination of the print head is also caused. It is possible to suppress the conspicuous local density (banding). This will be specifically described below.

  FIG. 7 is an explanatory diagram for explaining the effect of the ejection nozzle determination process using the ejection nozzle determination table M2 when printing is performed with the print head 50 tilted. FIG. 7A shows the print head 50 in an inclined state. As shown in FIG. 7A, the print head 50 is inclined in the rotational direction within a plane composed of the main scanning direction and the sub-scanning direction. When printing is performed with such a print head 50, in the discharge nozzle determination process in the present embodiment, the discharge nozzle determination table M2 based on the matrix MT1 having the characteristics (1) and the characteristics (3) is used. Since each raster line is printed by one main scan of the print head 50, the dots formed by the ink ejected from the nozzles belonging to the C row and the nozzles belonging to the D row are ejected onto the raster line where banding occurs. The dots formed by the ink are dispersed and mixed in the main scanning direction.

  Further, since the print head 50 is tilted, the dots based on the C row and the dots based on the D row are formed with their dot formation positions shifted in the sub-scanning direction. Accordingly, as shown in a region F1 in FIG. 7B, the dots based on the C row and the dots based on the D row are dispersed in the sub-scanning direction in a region where banding occurs due to the inclination of the print head 50. . Therefore, the banding due to the inclination of the print head 50 is suppressed from being noticeable.

  As a comparative example, for example, when the discharge nozzle determination process is performed using the discharge nozzle determination table M2 based on the matrix MT in which “C” and “D” are switched for each raster line, printing is performed. As shown in FIG. 7C, wide banding occurs in the sub-scanning direction between the raster line formed by dots based on the nozzles in the B row and the raster line formed by dots based on the D row. Further, since the dots are not dispersed in the banding region as shown in FIG. 7B, the banding is conspicuous.

  As can be seen from comparison with the comparative example, the matrix MT1 having the characteristic (1) can suppress the banding generated due to the inclination of the print head from being noticeable.

  As a second effect, the print head 50 provided in the printing apparatus 10 has nozzle rows A, B, C, and D each having a nozzle pitch of 1/120 [inch]. It is disposed at a position shifted in the sub-scanning direction in the mode (see FIG. 2). Therefore, by scanning and printing the print head 50 having such a configuration, it is possible to perform substantially the same printing as a print head having a nozzle pitch of 1/360 [inch]. In this embodiment, in order to obtain such an effect, the A column, the B column, and the C column are equally shifted by 1/360 [inch]. However, the present invention is not limited to this. The A, B, and C columns may be shifted in the sub-scanning direction with an arbitrary width within a range that is allowed for the configuration. In this embodiment, the nozzle pitch in each nozzle row is equal to 1/120 [inch]. However, the nozzle pitch is not limited to this and may be set to an arbitrary nozzle pitch within a range allowed for the configuration of the print head 50. Is possible.

  As a correspondence relationship with the claims, the carriage drive unit 32 and the transport unit 34 correspond to the head moving unit described in the claims, the CPU 21 corresponds to the control unit described in the claims, The nozzle row of the C row and the nozzle row of the D row correspond to the first nozzle group described in the claims, and the nozzle row of the A row and the nozzle row of the B row correspond to the first nozzle group described in the claims. This corresponds to the two nozzle groups.

B. Variations:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

(B1) Modification 1:
In the above embodiment, in the ejection nozzle determination process in step S108, only the image data formed by the ink ejected by the nozzle row belonging to the first nozzle group is considered, but the nozzle row belonging to the second nozzle group is ejected. Image data formed by the ink to be used may also be considered.
For example, depending on the image data such as R11 and R22 in FIG. 8, the amount of ink ejected by the nozzle row belonging to the second nozzle group is biased between the A row and the B row, that is, the ink between the ink cartridges 42 and 43. There is a bias in how to decrease Therefore, image data formed by ink ejected from the nozzle row belonging to the second nozzle group may be considered. That is, the usage amount of C and D may be determined based on the ratio of the usage amount of A and B as R33 in FIG.

  As a method of determining the usage amount of C and D based on the ratio of the usage amount of A and B, for example, there is a method using a random number. As shown in FIG. 8, when the ratio of the usage amounts of A and B is 1: 2, the usage ratio of C and D needs to be 4: 1. For each pixel, a random number of 1 to 100 is generated and assigned to use D when it is 1 or more and 20 or less, and use C when it is 21 or more and 100 or less. As a result, it is possible to further suppress uneven reduction (half reduction) of ink between the ink cartridges.

(B2) Modification 2:
In the above embodiment, the print head 50 and the ink supply mechanism are the modes shown in FIGS. 2 and 3. However, the present invention is not limited to this, and other print head configurations and ink supply mechanisms can be employed. . An example is shown in FIGS. In the aspect 1 shown in FIG. 9, the nozzle unit 52a includes four nozzle rows. Of the four nozzle rows of the nozzle unit 52a, two rows are supplied with ink from the ink cartridge 42a, and the remaining two rows are supplied with ink from the ink cartridge 43a. That is, ink is supplied from each ink cartridge for two nozzle rows. On the other hand, the nozzle unit 53a includes two nozzle rows. Of the two nozzle rows of the nozzle unit 53a, one row is supplied with ink from the ink cartridge 42a, and the remaining one row is supplied with ink from the ink cartridge 43a. Even if such an aspect 1 is adopted, it is possible to suppress the partial loss of ink.

  Further, FIG. 10 shows the aspect 2 as another print head configuration and ink supply mechanism. As can be seen from FIG. 10, the nozzle unit 52b receives ink for one nozzle row from each of the ink cartridges 42b, 43b, and 44b. Similarly to the nozzle unit 52b, the nozzle unit 53b also receives ink for one nozzle row from each of the ink cartridges 42b, 43b, 44b. Even if such a mode 2 is adopted, it is possible to suppress a decrease in the amount of ink.

  FIG. 11 shows the third aspect. This aspect is configured to include two nozzle units corresponding to the first nozzle group described in the claims. As can be seen from FIG. 11, each nozzle unit 52c, 53c, 54c is supplied with ink for one nozzle row from each of the ink cartridges 42c, 43c. Even if such an aspect 3 is adopted, it is possible to suppress a reduction in the amount of ink.

  As can be seen from Embodiment 1, Embodiment 2, and Embodiment 3 shown in this modification, when the number of ink cartridges provided in the printing apparatus is L (L is an integer of 2 or more), the position of each nozzle in the sub-scanning direction is A nozzle group (for example, the nozzle unit 53a) including L × a rows (a is an integer of 1 or more) having the same nozzle row receives ink supply for each row from each ink cartridge. This nozzle group corresponds to the first nozzle group described in the claims. Further, a nozzle group (for example, a nozzle unit) provided with L × b rows (b is an integer equal to or greater than 1) nozzle rows in which the positions of the arranged nozzles in the sub-scanning direction are different from the L × a row nozzle rows described above. 53a) receives ink supply for b rows from each ink cartridge. This nozzle group corresponds to the second nozzle group described in the claims. If the configuration of the print head and the ink supply mechanism based on such an aspect are adopted, it is possible to suppress a reduction in the amount of ink.

For example, in the case of the mode 3 in FIG. 11, the A column, the B column, and the C column are arranged at positions shifted from each other by 1/360 [inch] in the sub-scanning direction. In the row, the D row, the E row, and the F row, the positions of the nozzles of each nozzle row in the sub-scanning direction are the same.
In the case of the print head 50c, according to the image data to be printed, as an example, “C” and “D” in the characteristics (1) to (3) described in the first embodiment are changed to “C” and “D”. ”,“ E ”, and“ F ”can be printed to reproduce the characteristics.

That is,
Characteristic (1): “C”, “D”, “E”, and “F” may exist in each raster line in the matrix MT1.
Characteristic (2): The number of “C”, “D”, “E”, and “F” is the same or substantially the same in the entire matrix MT1.
Characteristic (3): In each raster line in the matrix MT1, the numbers of “C”, “D”, “E”, and “F” are the same or substantially the same.
Printing having these characteristics can be realized.

(B3) Modification 3:
In the above-described embodiment, the case where the printing process is performed by using one type of ink dot in the printing process has been described. However, the printing apparatus 10 may perform the printing process by dividing ink dots having a plurality of types of sizes. . For example, ink dots of three types of sizes, large dots, medium dots, and small dots, can be sorted. Whether large, medium, or small ink dots are to be ejected can be determined based on the gradation value of each pixel of the print data.

(B4) Modification 4:
In the above embodiment, a part of the functions realized by software may be realized by hardware, or a part of the functions realized by hardware may be realized by software. In addition, some of the functions realized by software may be provided in an external device (for example, a computer) connected to the printing apparatus 10. In the above-described embodiment, the printing apparatus 10 is described as a multi-function peripheral including a scanner and a copy. However, the printing apparatus 10 may be a printing apparatus dedicated to printing processing without being limited thereto. In this case, print processing can be performed by acquiring image data from a computer externally connected to the printing apparatus 10. Furthermore, although the printing apparatus 10 includes only black ink as a printing apparatus dedicated to monochrome printing, it may include color ink and color printing separately.

(B5) Modification 5:
In the above embodiment, the ink dots formed by the ink ejected from the nozzle row belonging to the first nozzle group are formed one pixel at a time from each of the L ink cartridges. In the case of performing processing one by one, the processing speed can be improved and simplified by sequentially forming two pixels.

  DESCRIPTION OF SYMBOLS 10 ... Printing apparatus, 11 ... Scanner part, 12 ... Card slot, 13 ... Communication connector, 14 ... Display, 15 ... Operation panel, 20 ... Control unit, 21 ... CPU, 22 ... RAM, 23 ... ROM, 24 ... Image data Acquisition unit, 25 ... monochrome conversion unit, 26 ... halftone processing unit, 27 ... discharge nozzle determination processing unit, 28 ... printing control unit, 30 ... printing mechanism unit, 32 ... carriage driving unit, 34 ... conveying unit, 40 ... carriage 41, head unit, 42, 42a, 42b, 42c ... ink cartridge, 43, 43a, 43b, 43c ... ink cartridge, 50, 50c ... print head, 52, 52a, 52b, 52c ... nozzle unit, 53, 53a, 53b, 53c ... nozzle unit, P ... print medium, NZ, NZ1, NZ2, NZ3 ... nozzle, M ... dither mask, R1, R2 ... raster line, M2 ... ejection nozzle determination table, MT1, MT2 ... matrix.

Claims (6)

A printing apparatus that performs printing upon receiving ink supplied from L (L is an integer of 2 or more) ink cartridges containing ink of the same hue,
A print head provided with a plurality of nozzle rows in which a plurality of nozzles for ejecting ink are arranged in a predetermined direction and spaced apart in a direction intersecting the direction;
A head moving unit that moves the print head in both scanning directions relative to the print medium, with the nozzle row separation direction as the main scanning direction and the nozzle arrangement direction as the sub-scanning direction;
A control unit that controls both the scanning of the print head by the head moving unit and the ejection of ink from the nozzles;
The print head is
Among the plurality of nozzle rows, the positions of the arranged nozzles in the sub-scanning direction are the same, and an L × a row (a is a predetermined correlation on printing by control from the control unit) A nozzle row of an integer of 1 or more is a first nozzle group that receives the supply of ink from each of the L ink cartridges by a row;
Among the plurality of nozzle rows, L × b (b is an integer of 1 or more) nozzles in which the positions of the nozzles arranged in the sub-scanning direction are different from the nozzles of the first nozzle group. The row includes a second nozzle group that receives the supply of ink from each of the b ink cartridges and the L ink cartridges,
Based on the number of ink dots determined by the halftone process for the image data, an ink dot formed by ink ejected by the nozzle row belonging to the first nozzle group is selected from any of the nozzle rows belonging to the first nozzle group. The printing device that determines whether to form. The printing apparatus according to claim 1,
The number of ink dots determined by the halftone process for the image data is the number of ink dots formed by the ink ejected by the nozzle rows belonging to the first nozzle group. The printing apparatus according to claim 1 or 2, wherein
An ink dot formed by ink ejected from a nozzle row belonging to the first nozzle group is formed in order of one pixel from each of the L ink cartridges. The printing apparatus according to claim 1,
The number of ink dots determined by the halftone process for the image data is the number of ink dots formed by the ink ejected by the nozzle row belonging to the second nozzle group,
Based on the ratio of each of the L ink cartridges of the number of ink dots formed by the ink ejected by the nozzle row belonging to the second nozzle group,
A printing apparatus that determines a ratio of each of the L ink cartridges to the number of ink dots formed by ink ejected by a nozzle row belonging to the first nozzle group. The printing apparatus according to any one of claims 1 to 4, wherein
A printing apparatus in which L = 2, a = 1, and b = 1. A printing method for a printing apparatus that performs printing by receiving ink supplied from L (L is an integer of 2 or more) ink cartridges containing ink of the same hue,
The printing apparatus includes a print head including a plurality of nozzle rows in which a plurality of nozzles that eject the ink are arranged in a predetermined direction and spaced apart in a direction intersecting the direction, and a separation direction of the nozzle rows as a main scanning direction. A head moving unit that moves the print head in both scanning directions relative to the print medium, with the nozzle arrangement direction as a sub-scanning direction, and both the scanning of the print head by the head moving unit. A control unit for controlling the ejection of ink from the nozzles,
The print head is
Among the plurality of nozzle rows, the positions of the arranged nozzles in the sub-scanning direction are the same, and an L × a row (a is a predetermined correlation on printing by control from the control unit) A nozzle row of an integer of 1 or more is a first nozzle group that receives the supply of ink from each of the L ink cartridges by a row;
Among the plurality of nozzle rows, L × b (b is an integer of 1 or more) nozzles in which the positions of the nozzles arranged in the sub-scanning direction are different from the nozzles of the first nozzle group. The row includes a second nozzle group that receives the supply of ink from each of the b ink cartridges and the L ink cartridges,
(A) Obtain the number of ink dots determined by halftone processing for image data;
(B) Based on the number of ink dots determined by halftone processing for the image data, ink dots formed by ink ejected by the nozzle rows belonging to the first nozzle group belong to the first nozzle group. A printing method that determines which of the nozzle rows to form.

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