JP2006218775A - Inkjet recording device - Google Patents

Abstract

To provide an ink jet recording apparatus capable of suppressing smear and boundary bleeding and recording high quality black character quality.
In a recording apparatus that performs recording using a recording head capable of recording one color ink, a black-to-white solid portion pixel detecting means, a black-to-color solid portion detecting means, and a color dot proximity pixel detecting means, , Black solid portion thinning data generation means, printing black data generation means, edge color addition selection means, edge color addition detection means, color thinning selection means, color thinning reverse image generation means, and reverse mask Selection means, first color dot provision data generation means, second color dot provision data generation means, color dot provision data generation means, color data generation means, data read / write selection means, recording means, An ink jet recording apparatus is configured.
[Selection] Figure 1

Description

  The present invention relates to an ink jet recording apparatus that performs recording using a plurality of recording heads capable of recording black ink and at least one color ink.

  Conventionally, an ink jet recording apparatus that performs recording on various recording media is capable of high-density and high-speed recording operations, and thus is applied as a printer as an output medium of various apparatuses, a portable printer, or the like. And it is commercialized.

  In general, an ink jet recording apparatus includes a carriage on which recording means (recording head) and an ink tank are mounted, a transport means for transporting a recording medium, and a control means for controlling them. A recording head that ejects ink droplets from a plurality of ejection openings is serially scanned in the direction (main scanning direction) perpendicular to the recording paper transport direction (sub-scanning direction), while recording the recording medium during non-recording. Intermittent conveyance with an amount equal to the width.

  This recording method performs recording by ejecting ink onto a recording sheet in accordance with a recording signal, and is widely used as a quiet recording method at a low running cost. In recent years, many products using a plurality of colors of ink and applied to a color recording apparatus have been put into practical use.

  In such a color ink jet recording apparatus, since black ink is frequently used for printing characters and the like, printing sharpness, sharpness, and high printing density are required. Therefore, a technique is known in which the penetrability of the black ink with respect to the recording material is reduced and the coloring material in the black ink is prevented from penetrating into the recording material (for example, see Patent Document 1).

  On the other hand, a color ink is a phenomenon in which when two types of inks of different colors are applied to a recording material adjacent to each other, the inks mix with each other at the boundary portion and the quality of the color image is deteriorated (bleeding). Will occur. In order to prevent this, a technique is known that increases the permeability to the recording material and prevents the color inks from being mixed on the surface of the recording material (for example, see Patent Document 2).

  However, when the ink set is used, the following two problems occur.

  First, although the color ink has high penetrability, the fixing time is fast, but the black ink has low penetrability, so that the dry fixing time is long. As a result, when the next page is continuously discharged after the previous page is discharged, the black ink of the previous page is not completely dried, so the print surface of the previous page and the next page The print back surface may be soiled (such a print surface and back surface stain is hereinafter referred to as “smear”). This problem becomes a major problem as the printing speed increases.

  Second, since black ink has low permeability, blur (boundary bleeding) occurs in the boundary region between black and color in an image where black and color are in contact. This is a problem that the quality of the color recording image is remarkably deteriorated.

  Conventionally, the following measures have been taken as these two solutions.

  The first countermeasure is a method of providing fixing means such as a heat fixing device. As a result, it is possible to prevent smear and boundary bleeding by fixing the ink on the paper surface at high speed.

  As a second countermeasure, there is a method of performing paper discharge waiting control. In this method, the printing start of the second sheet is temporarily stopped until the first sheet is printed and sufficiently dried, or the paper discharge operation is temporarily stopped after the second sheet is printed. As a result, smear can be suppressed.

  A third countermeasure is a method of printing by superimposing highly penetrating color ink on the black ink printing area. Since the black ink is printed on the paper surface coated with the color ink, the black ink is easily fixed on the paper surface, and smear can be suppressed. Furthermore, boundary bleeding can be suppressed by using an ink set in which black and color inks react and aggregate.

  The fourth measure is a method of printing the same color ink with high penetrability as the third measure on the black ink print area, and the area where smear is prevented by distinguishing the black and color areas. And the area where boundary bleeding is prevented, and the required amount of color ink is applied to each area to achieve both smear and boundary bleeding suppression.

JP 09-025442 A JP 55-0665269

  However, the above method has the following problems.

  That is, the first countermeasure is inevitable that an increase in the size and cost of the apparatus cannot be avoided by providing the fixing means. Further, in the serial printer, since the paper feed is intermittent, the feed unevenness may occur when the paper is passed through the fixing device.

  The problem with the second countermeasure is that throughput is reduced by waiting for paper discharge.

  The defect of the third countermeasure is that the sharpness of the black image is deteriorated and the quality of the black character is deteriorated by printing the color inks on top of each other. Further, when the color ink application amount necessary for preventing smear and the color ink application amount necessary for preventing boundary bleeding are different, it is difficult to achieve both suppression of smear and boundary bleeding.

  The problem of the fourth countermeasure is that the color ink application amount necessary for preventing smearing and the color ink application amount necessary for preventing boundary bleeding are separately applied to solve the problem of the third countermeasure. Although it is possible to achieve both smear and boundary bleeding suppression to a certain extent, it is better to apply the color ink necessary to prevent boundary bleeding due to the characteristics of each color ink adjacent to black. In some cases, it may be better, and when the density of adjacent colors is high, bleeding occurs regardless of whether or not color ink is applied. In addition, since all data must be processed, access to the memory increases.

  The present invention has been made in view of the above points, and an object of the present invention is to provide an ink jet recording apparatus capable of suppressing smear and boundary bleeding and recording high quality black character quality.

  In order to achieve the above object, a recording apparatus according to the present invention comprises the following arrangement.

  That is, in a recording apparatus that performs recording using a recording head capable of recording black ink and at least one color ink, a color dot area that is detected by calculating the logical sum of each color in order to identify the area where the color dot exists Detecting means and black-to-white solid part pixel detecting means for detecting a black-to-white solid part pixel, detecting a black-to-color solid part pixel detecting means for detecting a black-to-color solid part pixel, and detecting a black pixel in which color dots are close to each other The black solid portion thinning data for thinning out the black data by generating black solid portion data from the data detected by the color dot proximity pixel detecting means and the data detected by the means, and taking the logical product of the black solid portion data and the black thinning mask Generation means, black solid data and original Black data generation means for printing that generates black edge data from black data and performs logical OR with the black solid part thinned data generated by the above means, and color for preventing bleeding Edge portion color giving selection means for selecting data, edge portion color giving detecting means for detecting edge portion color giving data for preventing bleeding using the edge portion giving color selected by the edge portion color giving selection means and the original black, and A color thinning selection means for selecting a color thinning selection color for thinning out the color data adjacent to black, and a color thinning selection color selected by the color thinning selection means and an original black data for generating a color thinning inversion mask Between colors In this case, the color thinning inversion mask generated only for the color data selected by the color thinning selection means and the color thinning selection means is selected, and if not selected, the color thinning inversion is set to all “1”. Mask selection means, first color dot application data generation means for generating color dot data to be applied by taking a logical product of the black solid portion thinning data and the first color dot application mask, and the color dots Second color dot application data generating means for generating color dot data to be applied by taking the logical product of the neighboring pixels and the second color dot application mask; the first color dot application data generating means; Color dot provision data generation generated by taking a logical sum with the second color dot provision data generation means A logical sum of the color dot provision data generated by the color dot provision data generation means and the original color data, and the color thinning inversion mask selected by the color thinning inversion mask selection means and the logical product. Color data generation means for generating color data by taking the data, data read / write selection means for turning on / off data for each color in a configuration in which the means is connected to a memory, and generation by the means Printing black data and original black data, recording means for recording based on the color data and original color data generated by the means, printing black data generated by the means, and the means. Recording based on recorded color data It characterized by having a a recording unit.

  Preferably, the black-white solid part pixel detecting means calculates the number of black dots existing in a matrix of LxM (L, M = 1, 3, 5,... N, n + 2) centered on the pixel of interest. The pixel of interest is counted, and when the black dot exists in the pixel of interest and the count value exceeds a predetermined value, the pixel of interest is set as a black dot proximity pixel.

  Preferably, the black-to-color solid portion pixel detecting means calculates the number of black dots existing in a matrix of LxM (L, M = 1, 3, 5,... N, n + 2) centered on the pixel of interest. The pixel of interest is counted, and when the black dot is present in the pixel of interest and the count value exceeds a predetermined value, the pixel of interest is set as a black dot proximity pixel.

  Preferably, the color dot proximity pixel detecting means counts the number of color dots existing in an LxM (L, M = 1, 3, 5,... N, n + 2) matrix centered on the pixel of interest. When a black dot exists in the pixel of interest and the count value exceeds a predetermined value, the pixel of interest is set as a color dot proximity pixel.

  Preferably, the color dot proximity pixel detection means uses, as color dot proximity pixels, data obtained by ANDing data obtained by bolding original color data by a predetermined number of pixels in the vicinity of eight directions and original black data. .

  Preferably, the black solid portion data generation means includes the color dot proximity pixels detected by the color dot proximity pixel detection means, and the black-to-color solid portion pixels detected by the black-to-color solid portion pixel detection means. The black solid part data is obtained by logically summing the logical product of the above and the black-white solid part pixel detected by the black-white solid part pixel detecting means.

  Preferably, the black solid portion thinning data generation means obtains black solid portion thinning data by performing a logical product between the black solid portion data generated by the black solid portion data generation means and the black thinning mask.

  Preferably, the printing black data generating means includes black edge portion data generated by taking an exclusive OR between the black solid portion data generated by the black solid portion data generating portion and the original black data, and Black data for printing is obtained by performing a logical sum with the black solid portion thinning data generated by the black solid portion thinning data generating means.

  Preferably, the edge portion color provision selecting means selects a color to be subjected to color prevention for bleeding, and takes the logical sum of the original color data necessary for the selected color to obtain an edge portion color. .

  Preferably, the edge color addition detection unit counts the number of color dots existing in a matrix of LxM (L, M = 1, 3, 5,... N, n + 2) centered on the pixel of interest. When a black dot exists in the pixel of interest and the count value exceeds a predetermined value, the pixel of interest is set as a color dot proximity pixel.

  Preferably, the edge color addition detection means adds edge color data obtained by ANDing the data obtained by bolding the edge addition color data by a predetermined number of pixels in the vicinity of eight directions and the original black data. Let it be a pixel.

  Preferably, the color thinning selection means selects a color for thinning out the color data adjacent to black, and performs a logical sum of the original color original color data necessary for the selected color to obtain color thinning selection color data and To do.

  Preferably, the color-decimated inverted image generating means counts the number of color dots existing in an LxM (L, M = 1, 3, 5,... N, n + 2) matrix centered on the pixel of interest. When a black dot exists in the pixel of interest and the count value exceeds a predetermined value, the pixel of interest is set as a color dot proximity pixel.

  Preferably, the color decimation inverted image generating means includes a color decimation mask obtained by ANDing the data obtained by bolding the color decimation selected color data by a predetermined number of pixels in the vicinity of eight directions and the original black data. Taking the negative logical product in the above is defined as a color decimation inverted image.

  Preferably, the first color dot provision mask and the second color dot provision mask are provided independently for each ink color.

  Preferably, the color ink has three colors of yellow, magenta, and cyan.

  Preferably, the color dot detected by the color dot proximity pixel detecting means is data obtained by logically summing yellow, magenta and cyan data.

  Preferably, the black ink is an ink having a relatively low permeability, and the color ink is an ink having a relatively high permeability.

  Preferably, at least one of the color inks is a reactive ink that reacts with the black ink and aggregates.

  Preferably, the type of ink that reacts and aggregates with the black ink is a cyan ink.

  Preferably, the data read / write selection means selects reading and writing of each color data before accessing the memory, and reads / writes data from the memory by the selection.

  According to the present invention, it is possible to reduce the access time to the memory by selecting the reading / writing of the data to be processed, and by the color adjacent to the black, the width of the edge of the black data and the black edge between the black and the color By setting the optimal combination according to the ink characteristics and the characteristics of the printing device by switching the color addition to be added to and the color thinning that thins out the color between black and color, black data with poor fixability is thinned out, Appropriate color dots are applied to the boundary area between black and color, and boundary bleeding can be prevented by thinning out the optimum color.

  In addition, smear can be prevented by applying appropriate color dots to a region where the duty of black is high.

  Furthermore, since color dots are not applied to edge areas such as black characters, it is possible to provide an ink jet recording apparatus capable of recording a sharp black image.

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the embodiment described below, a printer is taken as an example of a recording apparatus using an inkjet recording method.
(1) Description of Color Recording Apparatus FIG. 27 is a schematic perspective view showing the configuration of an embodiment of a color inkjet recording apparatus to which the present invention can be applied.

  In FIG. 27, 202 is an ink cartridge. These are composed of an ink tank in which four color inks (black, cyan, magenta, and yellow) are respectively placed, and a recording head 201. Reference numeral 103 denotes a paper feed roller that rotates in the direction of the arrow while holding the print paper 107 together with the auxiliary roller 104 to feed the print paper 107 and to feed the print paper 107 in the same manner as the paper feed rollers 103 and 104. It also plays a role to suppress. A carriage 106 supports four ink cartridges, and moves the mounted ink cartridge 202 and recording head 201 together with printing. The carriage 106 is controlled so as to stand by at the home position indicated by the dotted line in the drawing when the recording apparatus is not printing or when the recovery operation of the recording head is performed.

  Prior to the start of printing, when a print start command is received, the carriage 106 located at the position shown in the figure (home position) drives the recording element provided in the recording head 201 while moving in the x direction to move the recording head on the paper surface. The area corresponding to the recording width is printed. When printing is completed up to the end of the paper along the scanning direction of the carriage, the carriage returns to the original home position and performs recording in the x direction again. The paper feed roller 103 rotates in the direction of the arrow shown in the figure after the previous print scan is finished and before the next print scan is started to feed the paper in the y direction by the required width. In this way, printing on one sheet is completed by repeating main scanning and paper feeding for printing. A recording operation for ejecting ink from the recording head is performed based on control from a recording control means (not shown).

  Further, in order to increase the recording speed, the recording is not performed only during the main scanning in one direction, but the recording is also performed in the return path when the main scanning recording in the x direction is finished and the carriage is returned to the home position side. It may be.

  In the example described above, the ink tank and the recording head are held on the carriage 106 in a separable manner. An ink jet cartridge in which an ink tank 202 that stores ink for recording and a recording head 201 that discharges ink toward the recording paper 107 are integrated may be used. Further, a multi-color integrated recording head that can eject a plurality of colors of ink from one recording head may be used.

Further, at the position where the above-described recovery operation is performed, a capping unit (not shown) for capping the front surface (ejection port surface) of the head, thickened ink and bubbles in the recording head are removed in a capped state by the capping unit, etc. A recovery unit (not shown) for performing the head recovery operation is provided. Further, a cleaning blade (not shown) or the like is provided on the side of the capping unit and is supported so as to be able to protrude toward the recording head 201, and can come into contact with the front surface of the recording head. Thus, after the recovery operation, the cleaning blade is projected into the moving path of the recording head, and unnecessary ink droplets and dirt on the front surface of the recording head are wiped off as the recording head moves.
(2) Description of Recording Head Next, the above-described recording head 201 will be described with reference to FIG.

  FIG. 28 is a perspective view of a main part of the recording head 201 shown in FIG. As shown in FIG. 28, the recording head 201 is formed with a plurality of discharge ports 300 at a predetermined pitch, and along the wall surface of each liquid passage 302 that connects the common liquid chamber 301 and each discharge port 300. A recording element 303 for generating ink discharge energy is provided. The recording element 303 and its circuit are made on silicon using semiconductor manufacturing technology. In addition, a temperature sensor (not shown) and a sub heater (not shown) are collectively formed on the same silicon by the same process as the semiconductor manufacturing process. A silicon plate 308 on which these electrical wirings are made is bonded to a heat radiating aluminum base plate 307.

  Further, the circuit connecting portion 311 on the silicon plate and the printed board 309 are connected by an extra fine wire 310, and a signal from the recording apparatus main body is received through the signal circuit 312. The liquid path 302 and the common liquid chamber 301 are formed by a plastic cover 306 made by injection molding. The common liquid chamber 301 is connected via the ink tank (see FIG. 27), the joint pipe 304, and the ink filter 305, and ink is supplied to the common liquid chamber 301 from the ink tank. .

The ink supplied from the ink tank to the common liquid chamber 301 and temporarily stored enters the liquid path 302 by capillary action and forms a meniscus at the discharge port 300 to keep the liquid path 302 filled. At this time, when the recording element 303 is energized through the electrodes (not shown) and generates heat, the ink on the recording element 303 is rapidly heated to generate bubbles in the liquid path 302, and the bubbles expand to discharge ports. Ink droplets 313 are ejected from 300.
(3) Description of Control Configuration Next, a control configuration for executing recording control of each part of the apparatus configuration will be described with reference to a block diagram shown in FIG.

  In the figure showing a control circuit, 400 is an interface for inputting a recording signal, 401 is an MPU, 402 is a program ROM for storing a control program executed by the MPU 401, 403 is various data (supplied to the recording signal and the head). In this case, the number of print dots, the number of ink recording head replacements, and the like can be stored. Reference numeral 404 denotes a gate array that controls supply of print data to the print head, and also controls data transfer among the interface 400, MPU 401, and DRAM 403.

  Reference numeral 405 denotes a carrier motor (CR motor) for conveying the recording head, and reference numeral 406 denotes a conveyance motor (LF motor) for conveying the recording paper. Reference numerals 407 and 408 denote motor drivers for driving the transport motor 405 and the carrier motor 406, respectively. Reference numeral 409 denotes a head driver that drives the recording head 410.

  In this embodiment, the color for edge processing is selected, only the selected data is read from the memory, the number of black dots existing in a 5 × 5 matrix centered on the black pixel of interest is counted, and the black dots If there are 25 dots, the pixel of interest is a black-to-white adjacent black dot solid pixel, the number of black dots present in a 3 × 3 matrix centered on the pixel of interest of black is counted, and 9 dots are If the pixel is present, the pixel of interest is a black-solid adjacent black dot solid pixel, and the number of color dots present in a 5 × 5 matrix centered on the pixel of interest of black is counted. If there is one color dot or more, and the pixel of interest is colored A dot adjacent pixel, and generates the Bk solid portion from these detected pixels.

  Further, a Bk edge portion is generated from the Bk solid portion and the original Bk data, and the Bk solid portion obtained by ANDing the Bk solid portion with the Bk thinning mask and the Bk edge portion are logically ORed to obtain the Bk beta for printing. Is generated.

  The first color dot provision data is generated by taking the logical product of the Bk solid portion thinning data and the first color dot provision mask. Also, the logical sum of each color data selected by the edge portion color selection given between the black and the color is taken, and the number of the selection color dots existing in the 3 × 3 matrix centered on the black pixel of interest is calculated. When the black pixel is present in the target pixel and one or more selective color dots are present, the target pixel is set as the edge portion provision pixel, and the logical product with the second color dot provision mask is obtained. Thus, the second color dot provision data is generated.

  Also, the logical sum of each color data selected by thinning out color selection for thinning out the color data between black and color is taken, and the number of selected thinning color dots existing in the 3 × 3 matrix centered on the black pixel of interest is calculated. Counting, when there are black dots in the pixel of interest and there are 1 or more selected thinned color dots, the pixel of interest is the thinned color pixel, the logical product of the color thinning mask is taken, and the pixel is inverted A color thinning reversal mask detected only for the color selected by the color thinning reversal mask selection is selected as the thinning reversal mask, and a color thinning reversal mask of “1” is selected for all the unselected colors.

The print Bk beta, the first color dot application data, the second color dot application data, the color thinning inversion mask, and the read original color data are combined, and only the selected color is written to the memory, and the edge By recording the processed color data and original color data, boundary bleeding and smear can be prevented and high-quality black characters can be recorded.
<Overall data processing>
FIG. 1 shows a flowchart for reading and writing data from a memory.

  In this process, black data is always read (S101), and it is determined whether or not to read Cyan data next (S102). When reading Cyan data from the memory, a Cyan data reading sequence is started ( S103) When reading is not performed, the Cyan data reading sequence is skipped.

  Next, it is determined whether or not reading of Magenta data is selected (S104). When reading Magenta data from the memory, a Magenta data reading sequence is started (S105), and when reading is not performed, Magenta data is read. It is determined whether or not to skip the reading sequence, and then to perform the reading of Yellow data (S105).

  When reading the Yellow data from the memory, the Yellow data reading sequence is started (S106), and when not reading, the Yellow data reading sequence is skipped. Next, the boundary detection processing is started with the read data (S108), it is determined whether or not black data writing is selected (S109), and when black data is written from the memory, the boundary detection is performed. Black data for printing is generated from the data detected in the processing (S110), a black data writing sequence is started (S111), and when reading is not performed, the black data for printing and black data reading sequence are skipped.

  Next, it is determined whether or not writing of cyan data is selected (S109). When writing cyan data from the memory, printing cyan data is generated from the data detected by the boundary detection processing (S110). Then, the Cyan data writing sequence is started (S111). When reading is not performed, the generation of printing cyan data and the reading sequence of Cyan data are skipped.

  Next, it is determined whether or not writing of the Magenta data is selected (S112). When writing the Magenta data from the memory, the printing Magenta data is generated from the data detected in the boundary detection processing ( In step S113, the Magenta data writing sequence is started (S114). When reading is not performed, the generation of printing Magenta data and the reading sequence of the Magenta data are skipped.

  Next, it is determined whether or not the writing of yellow data is selected (S115). When the yellow data is written from the memory, the printing yellow data is generated from the data detected in the boundary detection process (S116). Then, a yellow data writing sequence is started (S117), and when reading is not performed, generation of printing yellow data and skipping the reading sequence of yellow data are terminated. In this embodiment, only the Yellow performs data reading / writing from the memory.

  FIG. 2 shows detection of black-white solid pixels, detection of black-color solid pixels, detection of pixels in the vicinity of black dots, detection of edge-colored pixels, detection of color thinning pixels, generation of Bk data for printing, color It is a block diagram explaining the flow of generation | occurrence | production of dot provision data and the generation of CMY data for printing.

  OR of the data generated by the black dot neighboring pixel detection process (E1002) using the original Bk data (D1000), the original C data (D1005), the original M data (D1006), and the original Y data (D1007) Using the OR data (D1008) of the original C, M, and Y taken and the original Bk data (D1000), the logical product of the data generated in the black-to-color solid pixel detection process (E1001) and the black-white The Bk solid part data (D1001) is generated by taking the logical sum of the data generated in the detection process of the solid part pixel (E1000), and the Bk thinning part mask (D1008) is generated for the Bk solid part data (D1001). Bk solid part thinning data (D1032) is generated by taking the logical product of , Bk solid part data (D1001) and original black data (D1000) are printed by taking the logical sum of Bk edge part data (D1002) and Bk solid part thinned data (D1032) generated by taking the negative logical product of the original black data (D1000) Black data (D1028) is generated.

  Further, the Bk solid portion thinning data (D1032) to which color dots should be added for smear prevention is ANDed with the C mask 1 (E1009), M mask 1 (E1010), and Y mask 1 (E1011). Thus, C grant data 1 (D1018), M grant data 1 (D1019), and Y grant data 1 (D1020) are generated.

  Next, an edge portion obtained by ORing the data selected from the original C data (D1005), the original M data (D1006), and the original Y data (D1007) by the edge portion added color selection and the inverted data of the original black data. Using the color addition selection color area (D1010) and the original Bk data (D1000), edge portion color addition data detection processing (E1005) to which color dots should be added for border bleeding prevention is performed, and edge portion color addition pixel data is detected. (D1011) is generated.

  C edge data 2 (D1012), M is obtained by taking a logical product of edge mask color assignment pixel data (D1011) with C mask 2 (E1006), M mask 2 (E1007), and Y mask 2 (E1008). Grant data 2 (D1013) and Y grant data 2 (D1014) are generated. Next, the original Ck data (D1005), the original M data (D1006), and the original Y data (D1007) selected by thinning out color selection and the original Bk data (D1000) are used. Color thinning data detection processing (E1026) is performed to thin out color data between black and color, and color thinning data (D1025) is generated.

  The color thinning data (D1025) is exclusively ORed with the color thinning mask (D1026) to generate color thinning inversion mask data (D1033), and the color thinning inversion mask selection (D1027) is used to select the thinning color. The color decimation inversion mask (D1033) in which only the color data selected in (1024) is detected is selected, and the color decimation inversion mask data (D1033) is all set to color data not selected in the decimation color selection (1024). Color thinning inversion mask data (D1033) that is 1 'is selected.

Next, the logical thinning inversion mask data (D1033) selected by the color thinning inversion mask selection (D1027) is obtained by ORing the original C data (D1005), C addition data 1 (D1018), and C addition data 2 (D1012). And C data for printing (D1029) is generated. By performing the same processing, M data for printing (D1030) and Y data for printing (D1031) are generated.
<Detection of color dot area>
FIG. 3 shows an example of color dot area detection.

3 (a) shows the original image, FIG. 3 (e) shows the original black image, FIG. 3 (b) shows the original cyan image, FIG. 3 (c) shows the original magenta image, and FIG. 3 (d) shows the original yellow image. A color dot area image can be detected as shown in FIG. 3 (f) by calculating the logical sum of these original Cya, original Magenta, and original Yellow.
<Generation of black data for printing>
≪Detection of solid part data between black and white≫
FIG. 4 is a flowchart of black-white solid portion data detection processing.

  It is determined whether there are black dots in the pixel of interest and the total number of black dots present in the 5 × 5 matrix is 25 (S101). If the total number of black dots is 25, the bit of the pixel of interest is turned on (S102). Otherwise, the bit of the pixel of interest is turned off (S103). Subsequently, the pixel of interest is shifted (S104). If all the data is finished, the process is finished (S105). Otherwise, the above process is repeated. Here, although the threshold value of the total number of black dots is 25, it is preferable to use an optimum value according to the characteristics of the ink and the characteristics of the printing apparatus.

  FIG. 5 shows an example of detection of black-white solid part data.

  FIG. 5A shows a 5 × 5 matrix centered on the pixel of interest. FIG. 5B is a black original image. The black original data is processed while sequentially shifting the 5 × 5 matrix one pixel at a time. If the bit of the pixel of interest is turned on when the total number of black dots in the matrix is 25, a black solid portion pixel between black and white can be detected as shown in FIG.

As can be seen from FIG. 5C, only a relatively high duty area of black inside 2 dots between black and white is detected by this process.
≪Detection of solid part data between black and color≫
FIG. 6 is a flowchart of the process for detecting the black-color solid portion data.

It is determined whether there are black dots in the pixel of interest and the total number of black dots present in the 3 × 3 matrix is 9 (S201). If the total number of black dots is 9, the bit of the target pixel is turned on (S202). Otherwise, the bit of the pixel of interest is turned off (S203). Subsequently, the pixel of interest is shifted (S204). If all the data is finished, the process is finished (S205). Otherwise, the above process is repeated. Here, the threshold value of the total number of black dots is set to 9, but it is preferable to use an optimum value according to the characteristics of the ink and the characteristics of the printing apparatus.

  FIG. 7 illustrates an example of detection of black-color solid portion data.

  FIG. 7A shows a 3 × 3 matrix centered on the pixel of interest. FIG. 7B is a black original image. The black original data is processed while sequentially shifting the 3 × 3 matrix one pixel at a time. When the bit of the pixel of interest is turned on when the total number of black dots in the matrix is 9, black-white neighboring black solid portion pixels can be detected as shown in FIG. 7C.

As can be seen from FIG. 7C, this processing detects only a relatively high duty area of black inside one dot between black and color.
≪Detection of color dot neighboring pixel data≫
FIG. 8 is a flowchart of the detection process of color dot neighboring pixel data.

  It is determined whether there are black dots in the pixel of interest and the total number of color dots present in the 5 × 5 matrix is 1 or more (S301). If the total number of color dots is 1 or more, the bit of the pixel of interest is turned on (S302). Otherwise, the bit of the pixel of interest is turned off (S303). Subsequently, the target pixel is shifted (S304). If all the data is completed, the process ends (S305). Otherwise, the above process is repeated. Here, the threshold of the total number of color dots is set to 1, but it is preferable to use an optimum value in accordance with the characteristics of the ink and the characteristics of the printing apparatus.

  FIG. 9 shows an example of detection of color dot proximity pixels for preventing bleeding.

  FIG. 9A shows a 5 × 5 matrix centered on the pixel of interest. FIG. 9B is a black original image, and FIG. 9C is a color dot area image. The black original data and the color dot area data are processed while sequentially shifting the 5 × 5 matrix one pixel at a time. When the bit of the pixel of interest is turned on when the total number of color dots in the matrix is 1 or more, pixels near the color dot can be detected as shown in FIG.

As can be seen from FIG. 9D, only the boundary region between black and color is detected by this processing. In this boundary region, since the edge portion and the solid portion between black and color are mixed, the solid portion and the edge portion between black and color cannot be determined.
≪Bk solid part data generation≫
FIG. 10 shows an example of generation of Bk solid portion data.

  FIG. 10 (a) shows a black solid image between black and white detected by detecting the black / white solid part data, and FIG. 10 (b) shows a black / color between black and color detected by detecting the black / color solid part data. FIG. 10C shows a color dot neighborhood pixel image detected by detecting the color dot neighborhood pixel data. The logical product of the color pixel neighborhood pixel image and the black-to-black neighborhood black solid portion image and the black-white detected by the detection of the black-white solid portion data are logically ORed to obtain FIG. The black solid image of (d) is generated.

As can be seen from FIG. 10D, the solid portion between black and white is inside 2 dots, and the solid portion between black and color is inside 1 dot.
<< Generation of Bk edge data >>
FIG. 11 shows an example of generation of Bk edge portion data.

  FIG. 11A shows a black solid part image generated by generating the Bk solid part data, FIG. 11B shows original black data, and the exclusive OR of the black solid part image and the original black data is shown. By taking the above, the black solid image shown in FIG. 11C is generated.

As can be seen from FIG. 11C, the edge portion between black and white is 2 dots, and the edge portion between black and color is 1 dot.
<< Generation of Bk data for printing >>
FIG. 12 shows an example of generation of Bk solid portion thinning data.

  FIG. 12A shows the Bk solid portion data, and FIG. 12B shows a Bk thinning mask. The Bk solid portion data is ANDed with the Bk thinning mask to generate the black solid portion thinned pixel in FIG.

  FIG. 13 shows an example of generation of printing Bk data.

  FIG. 13A shows the Bk solid portion thinning data, and FIG. 13B shows the Bk edge portion data. The black pixel for printing shown in FIG. 13C is generated by calculating a logical sum of the Bk solid portion thinning data and the Bk edge portion data.

[Generation of color data for printing]
≪Generation of coloring data for smear prevention≫
FIG. 14 illustrates an example of generation of color dot application data for preventing smear. FIG. 14A shows black solid portion thinning data. FIGS. 14B to 14D show a cyan, magenta, and yellow mask 1 for generating a predetermined amount of application data. Here, the ratio of the amount of applied data for each color is 16% for cyan, 8% for magenta, and 8% for yellow. By giving the logical product of the black dot proximity pixel thinning data and the mask 1 of each color, the provision data of each color shown in FIGS. 14E to 14G is generated. Here, the amount of data to be applied for each color and the mask size are preferably set to appropriate values according to the characteristics of the ink and the configuration of the printing apparatus. The dot arrangement method in the mask may be regular or may be pseudo-random.
≪Detection of pixels adjacent to color dots to prevent bleeding≫
FIG. 15 is a diagram illustrating an example of generating an edge portion color addition selection color image.

  FIGS. 15A to 15C show the original color data, and FIG. 15D shows the edge portion color imparting selection color data selected by the edge portion imparting color selection. In this embodiment, Yellow is selected.

  In FIG. 15D, Yellow is selected, but it is preferable to select an optimum color according to the color of the read data, the characteristics of the ink, and the characteristics of the printing apparatus.

  FIG. 16 is a flowchart of the edge color-added pixel detection process for preventing bleeding between black and color.

  It is determined whether or not black dots are present in the pixel of interest and the total number of edge portion selection color dots present in the 3 × 3 matrix is 1 or more (S401). If the total edge portion added selection color dot number is 1 or more, the bit of the target pixel is turned on (S402). Otherwise, the bit of the pixel of interest is turned off (S403). Subsequently, the target pixel is shifted (S404). If all the data is completed, the process ends (S405). Otherwise, the above process is repeated. Here, although the threshold value of the total number of added edge portion selection color dots is 1, it is preferable to use an optimum value in accordance with the characteristics of the ink and the characteristics of the printing apparatus.

  FIG. 17 shows a detection example of color dot proximity pixels for preventing bleeding.

  FIG. 17A shows a 3 × 3 matrix centered on the pixel of interest. FIG. 17B is a black original image, and FIG. 17C is an edge portion addition selection color dot area image. The black original data and the edge portion addition selected color dot area data are processed while sequentially shifting the 3 × 3 matrix one pixel at a time. When the bit of the pixel of interest is turned on when the total number of color dots in the matrix is 1 or more, an edge portion added color pixel image for preventing bleeding can be detected as shown in FIG.

As can be seen from FIG. 17D, only the boundary region between black and the total edge portion added selection color is detected by this processing. By providing color dots in the boundary region, boundary bleeding can be prevented.
≪Generation of coloring data for preventing bleeding≫
FIG. 18 shows an example of generation of color imparting data for preventing bleeding.

FIG. 18A shows edge portion added color pixel data. FIGS. 18B to 18D show the cyan, magenta, and yellow masks 2 for generating a predetermined amount of application data. Here, the ratio of the amount of applied data for each color is 100% for cyan, 100% for magenta, and 100% for yellow. By applying a logical product of the edge portion added color pixel data and the mask 2 of each color, the added data of each color shown in FIGS. 18E to 18G is generated. Here, the reason why the amount of cyan applied is relatively large is that a recording apparatus of an ink system of a type in which only cyan ink is reactive to black ink and aggregates is assumed. It is preferable that the amount of data to be applied for each color and the mask size have appropriate values according to the characteristics of the ink and the configuration of the printing apparatus. The dot arrangement method in the mask may be regular or may be pseudo-random.
≪Generation of color thinning inversion mask≫
FIG. 19 shows a generation example of a color thinning selection color image.

  FIGS. 19A to 19C show original color data, and FIG. 19D shows color thinning selected color image data selected by thinning color selection. In this example, only Yellow is selected. In this thinning color selection, the selected color is generated by combining the original Cyan, the original Magenta, and the original Yellow.

  In FIG. 19D, only Yellow is selected, but it is preferable to select an optimum color according to the color of the read data, the characteristics of the ink, and the characteristics of the printing apparatus.

  FIG. 20 is a flowchart of color thinning data detection processing.

  It is determined whether or not black dots are present in the pixel of interest and the number of thinning selected color dots present in the 3 × 3 matrix is 1 or more (S501). If the number of color dots selected for thinning is 1 or more, the bit of the pixel of interest is turned on (S502). Otherwise, the bit of the pixel of interest is turned off (S503). Subsequently, the pixel of interest is shifted (S504). If all the data is completed, the process ends (S505). Otherwise, the above process is repeated. Here, the threshold value for the number of thinned-out color dots is set to 1, but it is preferable to use an optimum value according to the characteristics of the ink and the characteristics of the printing apparatus.

  FIG. 21 shows a detection example of color dot proximity pixels for preventing bleeding.

  FIG. 21A shows a 3 × 3 matrix centered on the pixel of interest. FIG. 21B shows a black original image, and FIG. 21C shows a color thinning selection color image. The black original data and the color thinning selection color data are processed while sequentially shifting the 3 × 3 matrix one pixel at a time. If the bit of the pixel of interest is turned on when the total number of color dots in the matrix is 1 or more, as shown in FIG. 21 (d), it is possible to detect a thinned-out area pixel image for preventing bleeding.

  As can be seen from FIG. 21D, only the boundary region between black and the color selected by the color thinning selection is detected by this processing. It is possible to prevent boundary bleeding by thinning out the color dots in the boundary region.

  FIG. 22 shows an example of generating a color thinning inverted image.

FIG. 22A shows the color thinning region pixel image, and FIG. 22B shows a color thinning mask. A color thinning inverted image shown in FIG. 22C is generated by taking a negative logical product with the color thinning mask for the color thinning region pixel image.
≪Generation of color data for printing≫
FIG. 23 is a flowchart of print color data generation processing.

  Bk-White solid part data is detected (S601). Subsequently, Bk-Color solid part data is detected (S602). Next, color dot neighboring pixel data is detected (S603), and Bk solid portion data is generated from these detected data (S604). Next, Bk edge portion data is generated by taking an exclusive OR between the Bk solid portion data and the original black data (S605). Subsequently, the Bk solid portion is ANDed with the Bk thinning mask to generate Bk solid portion thinning data (S606), and the Bk edge portion data and the Bk solid portion thinning data are logically summed to obtain black data for printing. Is generated (S607). Subsequently, by giving a logical product of the Bk solid portion thinning data and the cyan, magenta, and yellow masks 1, cyan, magenta, and yellow giving data 1 is generated (S 608).

  Next, the edge portion added color data is detected (S609), and the addition data 2 of cyan, magenta, and yellow is generated by taking the logical product with the cyan, magenta, and yellow masks 2 (S610). Further, color thinning data is detected (S611), and a negative logical product of the color thinning data and the color thinning mask is obtained to generate a color thinning inversion mask (S612). Finally, a logical sum of original cyan, magenta, and yellow data, each color giving data 1 and each color giving data 2 and a color thinning inversion mask that matches the color data selected by the thinning color selection. By taking the logical product, the printing cyan, magenta, and yellow data are obtained (S307).

  FIG. 24 shows printing cyan, FIG. 25 shows printing magenta, and FIG. 26 shows printing yellow data.

  In this embodiment, since only Yellow is written, only the yellow data for printing is used for printing, and the data stored in the original memory is used for the other colors.

  As described above, according to the present embodiment, by selecting reading / writing of data, the access time with the memory is reduced, and the width of the portion serving as the edge of the black data is changed by the color adjacent to the black. The solid part that hits the inside of the edge part is thinned out, and the black data that is thinned out is smeared to prevent smearing. In addition, it is switched for each color whether or not underlay for preventing border bleeding is performed depending on the color adjacent to black, and whether the adjacent color data is thinned out for each color is switched depending on the color adjacent to black. The black and white boundary black can be printed with sharp and sharp black characters, and the black and color boundary can be printed with boundary bleeding according to the ink color. It is possible to record a high-quality color image in which boundary bleeding between black and color is suppressed by switching whether or not to perform underprinting for prevention, and whether or not the boundary color is thinned out.

It is a flowchart figure at the time of reading / writing data from the memory of embodiment of this invention. Black-white solid pixel detection, black-color solid pixel detection, black dot neighboring pixel detection, edge-colored pixel detection, color thinning pixel detection, printing Bk data according to the embodiment of the present invention 5 is a block diagram for explaining a flow of generation of data, generation of color dot application data, and generation of print CMY data. It is a figure which shows the example of a detection of the color dot area of embodiment of this invention. It is a flowchart figure of the detection process of the solid part data between black-white of embodiment of this invention. It is a figure which shows the example of a detection of the solid part data between black-white of embodiment of this invention. It is a flowchart figure of the detection process of the solid part data between black-colors of embodiment of this invention. It is a figure which shows the example of a detection of the solid part data between black-colors of embodiment of this invention. It is a flowchart figure of the detection process of the color dot vicinity pixel data of embodiment of this invention. It is a figure which shows the example of a detection of the color dot proximity pixel for bleeding prevention of embodiment of this invention. It is a figure which shows the example of a production | generation of the Bk solid part data of embodiment of this invention. It is a figure which shows the production | generation example of Bk edge part data of embodiment of this invention. It is a figure which shows the example of a production | generation of the Bk solid part thinning-out data of embodiment of this invention. It is a figure which shows the production | generation example of the printing Bk data of embodiment of this invention. It is a figure which shows the example of generation | occurrence | production of the color dot provision data for smear prevention of embodiment of this invention. It is a figure which shows the example of a production | generation of the edge part color provision selection color image of embodiment of this invention. It is a flowchart figure of the detection process of the edge part color provision pixel for the bleeding prevention between the black and color of embodiment of this invention. It is a figure which shows the example of a detection of the color dot proximity pixel for bleeding prevention of embodiment of this invention. It is a figure which shows the example of the production | generation of the color provision data for bleeding prevention of embodiment of this invention. It is a figure which shows the example of a production | generation of the color thinning-out selection color image of embodiment of this invention. It is a flowchart figure of the detection process of the color thinning-out data of embodiment of this invention. It is a figure which shows the example of a detection of the color dot proximity pixel for bleeding prevention of embodiment of this invention. It is a figure which shows the example of a production | generation of the color thinning reverse image of embodiment of this invention. It is a flowchart figure of the production | generation process of the color data for printing of embodiment of this invention. It is a figure which shows the example of generation | occurrence | production of the printing cyan of embodiment of this invention. It is a figure which shows the example of a production | generation of the printing magenta of embodiment of this invention. It is a figure which shows the example of the production | generation of printing yellow of embodiment of this invention. 1 is a schematic perspective view showing a configuration of a color inkjet recording apparatus to which the present invention can be applied. 1 is a perspective view of a main part of a recording head to which the present invention can be applied. It is a control block diagram of an ink jet recording apparatus to which the present invention can be applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 103 Paper feed roller 104 Auxiliary roller 106 Carriage 201 Recording head 202 Ink cartridge 300 Discharge port 301 Common liquid chamber 302 Liquid path 303 Recording element 400 Interface 401 MPU
402 ROM
403 RAM
405 Carrier motor 406 Conveyance motor 410 Recording head

Claims (21)

In an inkjet recording apparatus that performs recording using a recording head capable of recording black ink and at least one color ink,
In order to identify the area where the color dots exist, color dot area detection means for detecting by taking the logical sum of each color,
A black-white solid part pixel detecting means for detecting a black-white solid part pixel;
A black-to-color solid part detection means for detecting a black-to-color solid part pixel;
Color dot proximity pixel detection means for detecting black pixels in which the color dots are close;
Black solid part data is generated from the data detected by the means, and black solid part thinned data generating means for thinning out black data by taking the logical product of the black solid part data and the black thinning mask;
Printing black data generating means for generating black edge data from black solid part data and original black data, and generating black data for printing by taking a logical sum with the black solid part thinned data generated by said means; ,
Edge color giving selection means for selecting color data for preventing bleeding,
Edge part color application detection means for detecting edge part color application data for preventing bleeding with the edge part application color selected by the edge part color application selection means and the original black;
Color thinning selection means for performing color thinning selection color for thinning color data adjacent to black,
Color thinning-inversion image generation means for generating a color thinning-inversion mask based on the color thinning-out selection color selected by the color thinning-out selection means and the original black data;
A color decimation inversion mask selection means for selecting a color decimation inversion mask generated only for the color data selected by the color decimation selection means, and setting all color decimation inversion to '1' if not selected;
First color dot application data generating means for generating color dot data to be applied by taking a logical product of the black solid portion thinning data and the first color dot application mask;
Second color dot application data generation means for generating color dot data to be applied by taking a logical product of the color dot proximity pixel and the second color dot application mask;
Color dot application data generating means generated by taking a logical sum between the first color dot application data generating means and the second color dot application data generating means;
By taking the logical product of the logical sum of the color dot provision data generated by the color dot provision data generation means and the original color data and the color thinning inversion mask selected by the color thinning inversion mask selection means Color data generating means for generating color data;
Data read / write selection means for turning on / off data read / write for each color in a configuration in which the means is connected to a memory;
Printing black data and original black data generated by the means; and recording means for recording based on the color data and original color data generated by the means;
An ink jet recording apparatus comprising:   The black-white solid portion pixel detecting means counts the number of black dots existing in a matrix of LxM (L, M = 1, 3, 5,..., N, n + 2) centered on the pixel of interest. 2. The ink jet recording apparatus according to claim 1, wherein when the black dot exists in the pixel and the count value exceeds a predetermined value, the pixel of interest is a black dot proximity pixel.   The black-to-color solid pixel detection means counts the number of black dots existing in a matrix of LxM (L, M = 1, 3, 5,..., N, n + 2) with the pixel of interest at the center. 2. The ink jet recording apparatus according to claim 1, wherein when the black dot exists in the pixel and the count value exceeds a predetermined value, the pixel of interest is a black dot proximity pixel.   The color dot proximity pixel detecting means counts the number of color dots existing in a matrix of LxM (L, M = 1, 3, 5,..., N, n + 2) centered on the pixel of interest, and determines the pixel of interest. 2. The ink jet recording apparatus according to claim 1, wherein when the black dot is present and the count value exceeds a predetermined value, the pixel of interest is a color dot proximity pixel.   The color dot proximity pixel detection means is characterized in that data obtained by ANDing the original color data with data obtained by bolding the original color data in a predetermined number of pixels in the vicinity of eight directions and the original black data is used as the color dot proximity pixel. The ink jet recording apparatus according to claim 1.   The black solid portion data generation means performs a logical product between the color dot proximity pixels detected by the color dot proximity pixel detection means and the black-color solid portion pixels detected by the black-color solid portion pixel detection means. 2. The ink jet recording apparatus according to claim 1, wherein black solid portion data is generated by performing a logical OR operation with the obtained one and the black-white solid portion pixel detected by the black-white solid portion pixel detecting means. .   The black solid portion thinning data generating means generates black solid portion thinning data by taking a logical product of the black solid portion data generated by the black solid portion data generating means and a black thinning mask. The ink jet recording apparatus according to claim 1.   The printing black data generating means includes black edge portion data generated by taking an exclusive OR between the black solid portion data generated by the black solid portion data generating portion and the original black data, and the black solid portion thinning-out. 2. The ink jet recording apparatus according to claim 1, wherein black data for printing is generated by performing a logical sum with the black solid portion thinned data generated by the data generating means.   The edge portion color provision selecting means selects a color to be subjected to bleeding prevention color generation, and generates an edge portion provision color by taking a logical sum of original color data necessary for the selected color. The ink jet recording apparatus according to claim 1.   The edge color addition detection means counts the number of color dots existing in a matrix of LxM (L, M = 1, 3, 5,..., N, n + 2) centered on the pixel of interest, and determines the pixel of interest. 2. The ink jet recording apparatus according to claim 1, wherein when the black dot is present and the count value exceeds a predetermined value, the pixel of interest is a color dot proximity pixel.   The edge color imparting detection means uses the data obtained by ANDing the data obtained by bolding the edge imparted color data by a predetermined number of pixels in the vicinity of eight directions and the original black data as edge color imparted pixels. 2. The ink jet recording apparatus according to claim 1, wherein   The color thinning selection unit selects a color to thin out color data adjacent to black, and generates color thinning selection color data by calculating a logical sum of original color original color data necessary for the selected color. The inkjet recording apparatus according to claim 1.   The color-decimated inverted image generation means counts the number of color dots existing in a matrix of LxM (L, M = 1, 3, 5,..., N, n + 2) centered on the pixel of interest, and determines the pixel of interest. 2. The ink jet recording apparatus according to claim 1, wherein when the black dot is present and the count value exceeds a predetermined value, the pixel of interest is a color dot proximity pixel.   The color decimated inverted image generation means performs a negative logical AND on a color decimated mask obtained by ANDing the data obtained by bolding the color decimated selection color data by a predetermined number of pixels in the vicinity of eight directions and the original black data. 2. An ink jet recording apparatus according to claim 1, wherein the image is taken as a color thinning reverse image.   2. The ink jet recording apparatus according to claim 1, wherein the first color dot application mask is provided independently for each ink color.   2. The ink jet recording apparatus according to claim 1, wherein the color inks are three colors of yellow, magenta, and cyan.   2. An ink jet recording apparatus according to claim 1, wherein the color dots detected by said color dot proximity pixel detecting means are data obtained by ORing yellow, magenta and cyan data.   2. The ink jet recording apparatus according to claim 1, wherein the black ink is an ink having a relatively low permeability, and the color ink is an ink having a relatively high permeability.   2. The ink jet recording apparatus according to claim 1, wherein at least one of the color inks is a reactive ink of a type that reacts and aggregates with the black ink.   7. The ink jet recording apparatus according to claim 6, wherein the ink that aggregates by reacting with the black ink is a cyan ink.   2. The ink jet recording apparatus according to claim 1, wherein the data read / write selection unit selects reading and writing of each color data before accessing the memory, and reads / writes data from the memory by the selection.

Images