JP2005144795A - Inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost of an inkjet recording device which can record a black character image of high quality level while inhibiting smears and also a color image of high picture quality with a realized reduction of a border bleeding between black and color. <P>SOLUTION: This inkjet recording device is equipped with a means for generating a second color dot imparting mask from a first color dot imparting mask. As procedures, first color dot imparting data are generated from the conjunction of a black dot proximity pixel and first color dot imparting mask, then second color dot imparting data are generated from the conjunction of a color dot proximity pixel and the second color dot imparting mask, and finally the color dot imparting data and original color data are combined. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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.

  2. Description of the Related Art Conventionally, ink jet recording apparatuses that perform recording on various recording media are capable of high-density and high-speed recording operations, and thus are applied as printers or portable printers as output media of various apparatuses, and It has been 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, the color ink has a phenomenon (bleeding) that, when two kinds of inks of different colors are applied to the recording material adjacent to each other, the inks are mixed at the boundary portion to deteriorate the quality of the color image. 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. However, 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 In some cases, the back side of the print is soiled (stains on the print side and back side are 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 countermeasures 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 case, 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. It is divided into a region for preventing boundary bleeding, and by imparting a necessary amount of color ink to each of them, smear and boundary bleeding are suppressed at the same time.
Japanese Patent Laid-Open No. 9-25442 JP 55-65269 A

  However, the above method has the following problems.

  The first problem is that the fixing device is provided to avoid the increase in size and cost of the apparatus. Further, in the serial printer, since the paper feeding is intermittent, there is a possibility that uneven feeding occurs 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. In addition, when the amount of color ink applied necessary for preventing smearing and the amount of color ink applied 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 solves the problem of the third countermeasure, but if this process is replaced with a logic circuit, the number of gates becomes enormous, and an increase in cost is inevitable.

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

  The present invention can solve the above problems by providing the following configuration.

(1) In a recording apparatus that performs recording using a recording head capable of recording black ink and at least one color ink.
A black dot proximity pixel detecting means for detecting a black pixel close to a black dot, a color dot proximity pixel detecting means for detecting a black pixel close to a color dot, and the black dot proximity pixel and the first color dot providing mask First color dot application data generating means for generating color dot data to be applied by taking a logical product, and second color dots by taking the logical product of the first color dot application mask and the mask mask Color dot application mask generating means for generating an application mask, and second color dot application for generating color dot data to be applied by taking the logical product of the color dot proximity pixel and the second color dot application mask Data generation means, the first color dot application data generation means, and the second color Color dot grant data composition means for synthesizing the color dot grant data generated by the dot grant data creation means by ORing with the original color data, black original data and the color dot grant data synthesis means An ink jet recording apparatus comprising: a recording unit that performs recording based on color data.

  (2) The black dot proximity pixel detection 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, and In the ink jet recording apparatus according to (1), when the black dot exists and the count value exceeds a predetermined value, the pixel of interest is a black dot proximity pixel.

  (3) The black dot proximity pixel detecting means bolds data obtained by inverting the original black data by a predetermined number of pixels in the vicinity of eight directions, and sets the data obtained by inverting the bold data again as black dot proximity pixels. The inkjet recording apparatus according to (1).

  (4) 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 In the ink jet recording apparatus according to (1), when the black dot exists and the count value exceeds a predetermined value, the pixel of interest is a color dot proximity pixel.

  (5) The color dot proximity pixel detecting means sets data obtained by ANDing data obtained by bolding the original color data by a predetermined number of pixels in the vicinity of eight directions and the original black data as color dot proximity pixels. The inkjet recording apparatus according to (1), which is characterized in that

  (6) The inkjet recording apparatus according to (1), wherein the first color dot application mask is provided independently for each ink color.

  (7) The inkjet recording apparatus according to (1), wherein the color inks are three colors of yellow, magenta, and cyan.

  (8) The ink jet recording apparatus according to (1), wherein the color dots detected by the color dot proximity pixel detecting unit are data obtained by logically summing yellow, magenta, and cyan data.

  (9) The inkjet recording apparatus according to (1), wherein the black ink is an ink having relatively low permeability, and the color ink is an ink having relatively high permeability.

  (10) The ink jet recording apparatus according to (1), wherein at least one of the color inks is a reaction type ink that reacts and aggregates with the black ink.

  (11) The ink jet recording apparatus according to (6), wherein the type of ink that reacts and aggregates with the black ink is a cyan ink.

  (12) The ink jet recording apparatus according to (1), wherein the mask mask is provided independently for only cyan and is used by shifting and rotating the mask in units of bits for each process.

  According to the present invention, by generating a second color dot application mask from the first color dot application mask, boundary color bleeding is prevented by applying appropriate color dots to the boundary area between black and color. can do. In addition, smear can be prevented by applying appropriate color dots to a region with a high black duty. Further, since color dots are not applied to edge regions such as black characters, it is possible to reduce the cost of an inkjet recording apparatus that can record a sharp black image.

  Hereinafter, embodiments of the recording apparatus of the present invention will be described with reference to the drawings.

  In the embodiments 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. 10 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 this figure, 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, which rotates in the direction of the arrow in the drawing while holding the printing paper 107 together with the auxiliary roller 104, and feeds the printing paper 107, and also serves to hold the printing paper 107 in the same manner as the rollers 103 and 104. Plays. 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 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).

  In addition, in order to increase the recording speed, recording is not performed only during main scanning in one direction, but recording is also performed in the return path when the main scanning recording in the x direction ends and the carriage returns to the home position side. There may be.

  In the example described above, the ink tank and the recording head are held on the carriage 106 so as to be separable. An ink jet cartridge in which an ink tank 202 that stores recording ink and a recording head 201 that discharges ink toward the recording paper 107 are integrated may be used. Furthermore, 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 protrude toward the recording head 201 so that it 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. 11 is a perspective view of the main part of the recording head 201 shown in FIG. As shown in FIG. 11, the recording head 201 has a plurality of discharge ports 300 each formed 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 ejection energy is provided. The recording element 303 and its circuit are made on silicon using semiconductor manufacturing technology. A temperature sensor (not shown) and a sub-heater (not shown) are also formed on the same silicon by the same process as the semiconductor manufacturing process. The silicon plate 308 on which these electrical wirings are made is bonded to the aluminum base plate 307 for heat dissipation. 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 of a plastic cover 306 made by injection molding. The common liquid chamber 301 is connected via the ink tank (see FIG. 10), 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) to generate 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. A signal circuit 312 is discharged 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 406 denotes a carrier motor (CR motor) for conveying the recording head, and reference numeral 405 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.

[Embodiment 1]
Outline of Embodiment 1 In this embodiment, the number of black dots existing in a 3 × 3 matrix centered on a black pixel of interest is counted, and when there are 9 black dots, the pixel of interest is black dot The first color dot application data is generated by taking the logical product of the adjacent pixel and the first color dot application mask. In addition, a second color dot application mask is generated by performing a logical product with the first color dot application mask using the C mask mask. Then, the number of color dots existing in the 3 × 3 matrix centered on the black pixel of interest is counted, and when the pixel of interest includes black dots and one or more color dots exist, the pixel of interest is selected. Second color dot application data is generated by taking the logical product of the color dot adjacent pixels and the second color dot application mask. The first color dot provision data and the second color dot provision data are combined with the original color data and recorded, thereby preventing boundary bleeding and smearing and recording high-quality black characters.

Overall Data Processing FIG. 1 illustrates the flow of black dot proximity pixel detection, second color dot application mask generation, color dot proximity pixel detection, color dot application data generation, and print data generation. FIG.

  By using the original Bk data (D1000), black dot proximity pixel data (D1001) is generated by performing detection processing (E1000) of black dot proximity pixels to which color dots should be added for smear prevention. The C addition data 1 (D1002) and the M addition data are obtained by taking the logical product of the C mask 1 (E1001), the M mask 1 (E1002), and the Y mask 1 (E1003) with respect to the black dot proximity pixel data (D1001). 1 (D1003), Y grant data 1 (D1004) is generated.

  Further, by using the C mask mask (D1020) and performing a logical product with the C mask 1 (E1001), a second color dot provision mask is generated (E1008). Next, OR data (D1008) of original C, M, Y obtained by ORing original C data (D1005), original M data (D1006), and original Y data (D1007) and original Bk data (D1000) are used. Thus, a color dot proximity pixel detection process (E1004) to which a color dot is to be added for boundary bleeding prevention is performed to generate color dot proximity pixel data (D1009). The C addition data 2 (D1010) and M assignment are obtained by taking the logical product of the C mask 2 (E1005), M mask 1 (E1006), and Y mask 1 (E1007) with respect to the color dot proximity pixel data (D1009). Data 2 (D1011) and Y addition data 2 (D1012) are generated. The logical sum of the original C data (D1005), C addition data 1 (D1002), and C addition data 2 (D1010) is taken to generate C data for printing (D1013). By performing the same processing, M data for printing (D1014) and Y data for printing (D1015) are generated. The original Bk data (D1000) is used as printing Bk data (D1016) without being processed.

Detecting process of color dot application target pixel Detection of black dot proximity pixel for smear prevention FIG. 2 is a flowchart of detection process of black dot proximity pixel for smear prevention.

  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 (S101). If the total number of black dots is 9, the bit of the target pixel 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 completed, the process ends (S105). 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. 3 is a diagram illustrating an example of detection of pixels adjacent to black dots.

  FIG. 3A illustrates a 3 × 3 matrix centered on the pixel of interest. FIG. 3B 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, as shown in FIG. 3C, a black dot proximity pixel for smear prevention can be detected.

  As can be seen from FIG. 3- (c), only the black area having a relatively high duty is detected by this processing. Since an edge region having a relatively low duty is not detected, color dots are not added, and the sharpness of the black image can be maintained.

Detection of Color Dot Proximity Pixels for Prevention of Bleeding FIG. 4 is a flowchart of detection processing of color dot proximity pixels for prevention of black and color bleeding.

  It is determined whether there are black dots in the target pixel and the total number of color dots present in the 3 × 3 matrix is 1 or more (S201). If the total number of color dots is 1 or more, the bit of the target pixel is turned on (S202). Otherwise, the bit of the pixel of interest is turned off (S203). Subsequently, the target pixel is shifted (S204). If all the data is completed, the process ends (S205). Otherwise, the above process is repeated. Here, although the threshold value of the total number of color dots is set to 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. 5 is a diagram showing an example of detection of color dot neighboring pixels for preventing bleeding.

  FIG. 5A shows a 3 × 3 matrix centered on the pixel of interest. FIG. 5B is a black original image, and FIG. 5C is a color original image. The black original data and the color original 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, a color dot application target pixel for preventing bleeding can be detected as shown in FIG.

  As can be seen from FIG. 5D, only the boundary area between black and color is detected by this processing. By providing color dots in the boundary region, boundary bleeding can be prevented.

Generation of Second Color Dot Application Mask FIG. 6 shows an example of generation of the second color dot application mask. FIG. 6A shows a first color dot application mask for generating a predetermined amount of application data for cyan. FIG. 6B is a mask mask, and the second color dot provision mask for cyan in FIG. 6C is generated by performing a logical product with the first color dot provision mask. Can do. Further, as shown in FIG. 6D, the mask for mask is masked evenly by shifting the mask for each process.

Generation of color dot application data Generation of color dot application data for preventing smear FIG. 7 illustrates an example of generation of color dot application data for preventing smear. FIG. 7A shows black dot proximity pixel data. FIGS. 7B to 7D 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 18% for cyan, 5% for magenta, and 5% for yellow. By giving the logical product of the black dot proximity pixel data and the mask 1 of each color, the application data of each color shown in FIGS. 7E to 7G is generated. Here, it is preferable that the amount of data to be applied for each color and the mask size are 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.

Generation of color dot application data for preventing bleeding FIG. 8 shows an example of generation of color dot application data for preventing bleeding. FIG. 8A shows color dot proximity pixel data. FIGS. 8B to 8D 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 30% for cyan, 5% for magenta, and 5% for yellow. By giving the logical product of the color dot proximity pixel data and the mask 2 of each color, the application data for each color shown in FIGS. 8- (e) to (g) is generated. Here, the reason why the amount of cyan applied is relatively large is that a recording apparatus of an ink system in which only cyan ink has reactivity with black ink and is aggregated is assumed. 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.

Generation of print color data FIG. 9 is a flowchart of print color data generation processing. Black dot proximity pixel data is detected (S301). Subsequently, the addition data 1 of cyan, magenta, and yellow is generated by taking the logical product of the black dot proximity pixel data and the cyan, magenta, and yellow mask 1 (S302). Next, color dot proximity pixel data is detected (S303), and the addition data 2 of cyan, magenta, and yellow is generated by taking the logical product with the mask 2 of cyan, magenta, and yellow (S304). Finally, the logical sum of the original cyan, magenta, and yellow data, each color imparting data 1 and each color imparting data 2 is obtained to obtain printing cyan, magenta, and yellow data (S305).

  As described above, according to the present embodiment, color dots are applied to relatively high duty black data excluding the edge region of characters, thereby preventing smearing in the high duty region and sharp edges. And high-quality black characters can be recorded. Furthermore, by applying color dots that differ from the amount of smear color dots applied to the boundary area between black and color, it is possible to record high-quality color images that suppress boundary bleeding between black and color. Become.

FIG. 3 is a block diagram illustrating a flow of detection of color dot application target pixels, generation of color dot application data, and generation of print data according to the first exemplary embodiment. FIG. 3 is a flowchart of detection processing for a color dot application target pixel for smear prevention according to the first embodiment. FIG. 2 is a diagram illustrating a detection example of a color dot application target pixel for preventing smear according to the first embodiment. FIG. 3 is a flowchart of detection processing of a pixel to be applied with color dots for preventing black and color bleeding in the first embodiment. FIG. 4 is a diagram illustrating a detection example of a color dot application target pixel for preventing bleeding according to the first exemplary embodiment. FIG. 6 illustrates a generation example of a second color dot application mask according to the first embodiment. FIG. 5 is a diagram illustrating an example of generation of smear prevention color dot application data according to the first exemplary embodiment. FIG. 4 is a diagram illustrating an example of generation of color dot application data for preventing bleeding according to the first exemplary embodiment. FIG. 5 is a flowchart of print color data generation processing according to the first embodiment. 1 is a schematic perspective view showing a configuration of an embodiment 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

103 Paper feeding roller 104 Auxiliary roller 106 Carriage 107 Printing paper 201 Recording head 202 Ink cartridge 300 Discharge port 301 Common liquid chamber 302 Liquid path 303 Recording element 304 Joint pipe 305 Ink filter 306 Plastic cover 307 Aluminum base plate 308 Silicon plate 309 Printing board 310 Super fine wire 311 Circuit connection 312 Signal circuit 400 Interface 401 MPU
402 Program ROM
403 RAM (DRAM)
404 Gate array 405 Conveyance motor (LF motor) (paper feed motor)
406 Carrier motor (CR motor) (carriage motor)
407, 408 Motor driver 409 Head driver 410 Recording head (head type signal generation circuit)

Claims (12)

In a recording apparatus that performs recording using a recording head capable of recording black ink and at least one color ink,
A black dot proximity pixel detecting means for detecting a black pixel close to a black dot, a color dot proximity pixel detecting means for detecting a black pixel close to a color dot, and the black dot proximity pixel and the first color dot providing mask First color dot application data generating means for generating color dot data to be applied by taking a logical product, and second color dots by taking the logical product of the first color dot application mask and the mask mask Color dot application mask generating means for generating an application mask, and second color dot application for generating color dot data to be applied by taking the logical product of the color dot proximity pixel and the second color dot application mask Data generation means, the first color dot application data generation means, and the second color Color dot grant data composition means for synthesizing the color dot grant data generated by the dot grant data creation means by ORing with the original color data, black original data and the color dot grant data synthesis means An ink jet recording apparatus comprising: a recording unit that performs recording based on color data.   The black dot proximity 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, and sets the black dot as the pixel of interest. 2. The inkjet recording apparatus according to claim 1, wherein the pixel of interest is a black-dot proximity pixel when a pixel exists and the count value exceeds a predetermined value.   The black dot proximity pixel detection means bolds data obtained by inverting original black data by a predetermined number of pixels in the vicinity of eight directions, and sets data obtained by inverting the bold data again as black dot proximity pixels. Item 10. The ink jet recording apparatus according to Item 1.   The color dot proximity pixel 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 sets the black dot as the pixel of interest. 2. The inkjet recording apparatus according to claim 1, wherein the pixel of interest is a color dot proximity pixel when there is a pixel and the count value exceeds a predetermined value.   The color dot proximity pixel detecting means is characterized in that 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 is used as a color dot proximity pixel. The ink jet recording apparatus according to claim 1.   The inkjet 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. The ink jet recording apparatus according to claim 1, wherein the color dots detected by the color dot proximity pixel detecting means are data obtained by logically summing yellow, magenta, and cyan data.   The inkjet recording apparatus according to claim 1, wherein the black ink is an ink with relatively low permeability, and the color ink is an ink with relatively high permeability.   2. The ink jet recording apparatus according to claim 1, wherein at least one of the color inks is a reaction type ink 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 mask mask is used only for cyan, and is used by shifting and rotating the mask in units of bits for each process.

Images