JP5743439B2 - Inkjet recording apparatus and inkjet recording method - Google Patents

Description

  The present invention relates to an ink jet recording apparatus and an image processing method for the recording apparatus. In particular, the present invention relates to an image processing method for reducing unevenness of bronze generated on an image when a connection head configured by arranging a plurality of chips is used.

  An ink jet recording apparatus records an image by adhering ink to a recording medium. However, in the output image, an image detrimental effect called bronzing may be confirmed. Bronze is considered to occur due to the aggregation of ink on the surface of a recording medium, and is confirmed as a shift in glossiness or color developability in an image. Therefore, bronze is affected by the mutual relationship between the ink components and the recording medium, and even with the same recording medium, some inks are likely to appear bronze, and some inks are difficult to appear.

  Patent Document 1 discloses a method for avoiding as much as possible the use of ink that is likely to generate bronzing by changing the UCR rate of basic color inks composed of cyan, magenta, and yellow inks and black inks. . Further, Patent Document 2 discloses a method of suppressing the bronze of the entire image by performing an overcoat with yellow ink which is less likely to generate bronzing after recording with a group of inks which are liable to generate bronzing.

JP 2001-138555 A JP 2004-181688 A

  Incidentally, in recent years, for example, a long recording head as shown in FIGS. 6A and 6B is useful for high-speed image output. In the connecting head as shown in FIGS. 6A and 6B in which a plurality of chips 601 each having a plurality of discharge ports 811 arranged are connected together, the recording medium or the connecting head is moved relatively. Ink is ejected from each ejection port at a predetermined frequency. In an image recorded by such a method, an area recorded at the connecting portion of the connecting head and an area recorded at the non-connecting portion are mixed, but the recording configuration is different in these areas. Specifically, ink is applied by one chip in an area recorded at a non-joining portion, but ink is applied by two chips in an area recorded at a joining portion. Therefore, the area recorded at the connecting portion is more susceptible to the arrangement error between the chips and the time required for ink application is longer than the area recorded at the non-connecting portion. Then, such a difference in the recording configuration between the connected portion and the non-connected portion appears as a difference in bronze on the image, and invites a new image problem such as uneven bronze.

  Both Patent Document 1 and Patent Document 2 disclose methods for reducing bronzing. However, all of these patent documents provide ink that does not easily cause bronzing to an area that is likely to cause bronzing, and the degree of bronzing differs depending on the recording configuration even if the same ink is used. Not done. Therefore, the above-mentioned bronze unevenness unique to the connecting head that can occur even in a single color cannot be solved by using the method of Patent Document 1 or Patent Document 2.

  The present invention has been made to solve the above problems. Accordingly, an object of the present invention is to provide an ink jet recording apparatus capable of reducing the non-uniform bronze unevenness of the connecting head and an image processing method for reducing the non-uniform bronze.

The present invention therefore has a plurality of chips in which a plurality of discharge ports for discharging ink of the same color are arranged in a predetermined direction, the one end portion in the predetermined direction of the first chip of the plurality of chips One of the arranged ejection ports and one of the second chips arranged at positions adjacent to the first chip in the predetermined direction are arranged at the end on the first chip side in the predetermined direction. part of the discharge port and is, in so that provided overlapping portions can be recorded on the same area on the recording medium by arranged in an intersecting direction that intersects the predetermined direction, wherein the plurality of chips are arranged in the predetermined direction recording A first recording head for ejecting a first color ink containing a cohesive color material, and aggregation of the color material contained in the first color ink. The first color different from the first color having the suppressing property. A of using a plurality of said recording head at least including a second of said recording head for ejecting the color ink jet recording apparatus for recording an image on said recording medium, in the second recording head A controller that controls ejection of the second color ink, and when reproducing a color on a straight line from white to the first color in the L * a * b * space on the recording medium, The first recording head in the first recording head of the first region on the recording medium, wherein the amount of the first color ink applied by the overlapping portion of the first recording head is the first amount. Deviation in the color development of the image due to the relative recording position deviation between the chip and the second chip is caused by the amount that the overlapping portion of the first recording head applies the first color ink. A second area on the recording medium which is a quantity In the case where the amount of the second color ink is larger than the second region, the control unit applies the second color ink to the second region in an amount that the second recording head applies the second color ink to the first region. The ejection of the second color ink is controlled so as to be larger than the applied amount .

  According to the present invention, it is possible to reduce the hue shift between the connecting portion and the non-connecting portion in the medium density portion, and it is possible to make the unique bronzing unevenness of the connecting head inconspicuous.

1 is a schematic configuration diagram of an ink jet recording apparatus applicable to the present invention. It is a block diagram which shows the connection relation of an inkjet recording device and an external device. It is a block diagram for demonstrating the structure of control in a control apparatus. It is a block diagram for demonstrating the process of the image processing which CPU performs. It is a figure for demonstrating a color separation process notionally. (A) And (b) is the schematic of the connection head which can be used by this invention. (A)-(c) is a figure for demonstrating the difference in the recording method of the connection part and non-connection part in two chips | tips. (A)-(c) is typical sectional drawing for demonstrating a mode that the ink droplet discharged from the recording head landed on a recording medium in the normal state. (A)-(c) is a figure explaining the difference between the fixing in which bronze does not generate | occur | produce, and the fixing in which bronze generate | occur | produces. It is a figure which shows the example of a colorimetry method for judging the grade of bronze. (A)-(c) is a figure explaining the difference in bronze by the case where two ink droplets are recorded adjacently, and the case where they are recorded redundantly. (A)-(d) is a figure explaining the grade of the bronze according to the duplication rate. (A) And (b) is a figure which shows the arrangement | positioning state of the several dot recorded by two chips | tips with which the manufacturing error has arisen in the positional relationship. (A)-(e) is a figure which compares the appearance of the bronze with respect to a recording duty by the presence or absence of a recording position shift. (A)-(c) is a figure for demonstrating the fixing state at the time of recording the ink which is hard to aggregate to the area | region which records the ink which is easy to aggregate. It is a figure which shows the general relationship between multi-value data and a recording duty. 6 is a diagram illustrating a relationship between multi-value data and a recording duty in Embodiment 1. FIG. It is a figure which shows the relationship between the multi-value data in Example 2, and a recording duty. (A) And (b) is a figure which shows the relationship between the multi-value data in Example 3, and a recording duty. It is a figure which shows the color area which a recording device can express in L ^* a ^* b ^* space. It is a figure which shows the relationship between the multi-value data in Example 4, and a recording duty. (A)-(d) is a figure which shows the relationship between the multi-value data of cyan and the recording duty of each ink color from white to cyan and from black to cyan.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic configuration diagram of an ink jet recording apparatus 800 applicable to the present invention. The ink tank 610 contains ink for six colors of cyan (C), magenta (M), yellow (Y), black (K), and gray (Gy), and supplies them to the recording head 600. The recording head 600 ejects ink of each color at a predetermined frequency toward the recording medium 630 according to the recording data corresponding to each ink. While the recording head 600 ejects ink, the recording medium 630 is conveyed in the direction of the arrow at a speed corresponding to the predetermined frequency, whereby an image according to the recording data is recorded on the recording medium 630. The recording data to be recorded by the recording head 600 is generated by the control device 620 processing image data received from an externally connected host device.

  FIG. 2 is a block diagram for explaining a connection relationship between the ink jet recording apparatus 800 of the present embodiment and an external device. The ink jet recording apparatus 800 of this embodiment is connected to a host device 810 and an optical measuring device 820, and the host device 810 and the optical measuring device 820 are also connected to each other. The ink jet recording apparatus 800 performs image processing, which will be described later, on the image data received from the host apparatus 810, and then ejects ink onto a recording medium based on the processed image data. The optical measuring device 820 can optically measure the image recorded by the inkjet recording apparatus 800 and transmits the measurement result to the host apparatus 810.

  FIG. 3 is a block diagram for illustrating a control configuration of the control device 620 provided in the inkjet recording apparatus 800. The input interface 621 receives input information from a host device connected to the outside of the recording apparatus, an optical measuring instrument (to be described later), and an operation unit provided in the recording apparatus and allowing a user to input instructions. The CPU 622 controls the entire recording apparatus according to various programs stored in the ROM 624. For example, the CPU 624 generates recording data that can be recorded by the recording head 600 from image data received from the host device via the input interface 621 in accordance with a program stored in the ROM 624. The generated recording data is output to the recording head 600 via the output interface 623. In addition to the above programs, the ROM 624 also stores various parameters such as a color separation table used for image processing. The ROM 624 can be a rewritable nonvolatile ROM. The RAM 620 is used as a work area when the CPU 622 executes various processes in addition to the image processing described above.

  FIG. 4 is a block diagram for explaining image processing steps executed by the CPU 622. Image data received from the host device via the input interface is RGB multi-value (for example, 256-value) data. The RGB multi-value data is first input to the resolution conversion unit 21 and converted to a resolution that can be recorded by the recording apparatus. Thereafter, the color separation conversion unit converts the RGB multi-value data into CMYKGy multi-value data corresponding to the ink colors used in the printing apparatus. In this color separation process, a three-dimensional lookup table (color separation table) that converts RGB multi-value data into CMYKGy multi-value data is referred to.

  FIG. 5 is a diagram for conceptually explaining the color separation process. A space represented by three-dimensional axes of red (R), green (G), and blue (B) input to the color separation processing is cyan (C), magenta (M), yellow ( Y). In addition, the achromatic color from black to white indicated by a broken line in the figure can be expressed by black ink (K) or gray ink (Gy). Therefore, for example, a point expressed by a combination of 256 values of RGB can be expressed by a combination of 256 values of CMYKGy. In the present embodiment, a lookup table (LUT) is prepared in advance so that each RGB combination is associated with CMYKGy on a one-to-one basis. In the color separation processing, the input RGB multi-value data is converted into CMYKGy multi-value data by referring to the color separation table 20 and output.

  The multivalued data of CMYKGy converted by the color separation conversion unit 22 is then input to the halftone processing unit 23 and converted into binary data that defines recording (1) or non-recording (0) for each color.

  The binary data of each color for which recording (1) or non-recording (0) is determined is input to the mask processing unit 24. In the mask processing unit 24, each recording data is distributed to recording elements (ejection ports) that actually perform recording. When there are a plurality of recording elements (ejection ports) capable of recording the recording data of interest, the recording data is distributed to any one of the plurality. A specific distribution method will be described later.

  In FIG. 4, the image processing configuration mainly including the resolution conversion unit 21, the color separation conversion unit 22, and the halftone processing unit 23 has been described. However, other image processing units having various purposes can be provided. For example, if the color space that can be represented by the input data RGB and the color space that can be represented by the ink CMYKGy of the printing apparatus do not match as shown in FIG. Signal value conversion may be performed to take advantage of the characteristics. It is also possible to perform γ correction so that the density expressed on the recording medium is linear with respect to the CMYKGy multilevel signal. Furthermore, the processing having these functions can be configured to be included in the color separation conversion unit and the halftone processing unit.

  Next, ink components usable in the present embodiment will be described. In this embodiment, as an example, cyan ink that is relatively easy to generate bronze and magenta, yellow, black, and gray inks that are relatively difficult to generate bronze are used. Examples of combinations of inks for satisfying such a relationship are given below.

(Cyan color material)
C. I. Phthalocyanine dyes such as Direct Blue 86, 199, and 307 are used. However, the applicable condition of the present invention is not limited to these, as long as it is easier to bronz than the light cyan color material.

(Yellow color material)
The following dyes can be used.
C. I. Direct yellow: 8, 11, 12, 27, 28, 33, 39, 44, 50, 58, 85, 86, 87, 88, 89, 98, 100, 110, 132, 173.

C. I. Acid Yellow: 1, 3, 7, 11, 17, 23, 25, 29, 36, 38, 40, 42, 44, 76, 98, 99.
C. I. Pigment Yellow: 1, 2, 3, 12, 13, 14, 15, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 114, 128, 138, 180.

(Magenta color material)
The following dyes can be used.
C. I. Direct Red: 2, 4, 9, 11, 20, 23, 24, 31, 39, 46, 62, 75, 79, 80, 83, 89, 95, 197, 201, 218, 220, 224, 225, 226 227, 228, 229, 230.
C. I. Acid Red: 6, 8, 9, 13, 14, 18, 26, 27, 32,
35, 42, 51, 52, 80, 83, 87, 89, 92, 106, 114, 115, 133, 134, 145, 158, 198, 249, 265, 289.
C. I. Food Red: 87, 92, 94.
C. I. Direct violet 107.
C. I. Pigment Red: 2, 5, 7, 12, 48: 2, 48: 4, 57: 1, 112, 122, 123, 168, 184, 202.

(Black color material)
The following dyes can be used.
C. I. Direct black: 17, 19, 22, 31, 32, 51, 62, 71, 74, 112, 113, 154, 168, 195.
C. I. Acid Black: 2, 48, 51, 52, 110, 115, 156.
C. I. Food black 1,2. Carbon black.

  Moreover, the following can be used for the solvent and additive for dissolving said each color dye. First, water and a water-soluble organic solvent are used as an aqueous medium. Here, the following materials are mentioned as a preferable water-soluble organic solvent. C1-C4 alkanols such as ethanol, isopropanol, n-butanol, isobutanol, sec-butanol and tert-butanol; carboxylic acid amides such as N, N-dimethylformamide or N, N-dimethylacetamide; acetone. Ketones such as methyl ethyl ketone and 2-methyl-2-hydroxypentan-4-one, or cyclic ethers such as ketoalcohol, tetrahydrofuran and dioxane, glycerin, ethylene glycol, diethylene glycol and triethylene glycol; Tetraethylene glycol, 1,2- or 1,3-propylene glycol, 1,2- or 1,4-butylene glycol, polyethylene glycol, 1,3-butanediol, 1,5-pentanediol, 1,2-hexane Diol, 1,6-hexanediol. Polyhydric alcohols such as dithioglycol, 2-methyl-1,3-propanediol, 1,2,6-hexanetriol, acetylene glycol derivatives, trimethylolpropane, and ethylene glycol monomethyl (or ethyl) ether. Alkyl ethers of polyhydric alcohols such as diethylene glycol monomethyl (or ethyl) ether, triethylene glycol monoethyl (or butyl) ether, 2-pyrrolidone, N-methyl-2-pyrrolidone. Suitable examples include heterocycles such as 1,3-dimethyl-2-imidazolidinone and N-methylmorpholine, sulfur-containing compounds such as dimethyl sulfoxide, urea, and urea derivatives.

  In addition to this, the ink composition of the present embodiment includes a surfactant, a pH adjuster, a chelating agent, a rust inhibitor, an antiseptic, an antifungal agent, an ultraviolet absorber, a viscosity modifier, an antifoaming agent, In addition, various additives such as a water-soluble polymer may be contained.

  FIGS. 6A and 6B are schematic diagrams for explaining a state when the recording head 600 usable in the present embodiment is observed from the ejection port side. In any of the drawings, the recording heads of the respective colors are arranged in the order of gray, black, yellow, magenta, and cyan from the upstream side in the y direction, and ink is applied to the moving recording medium in this order. Each recording head is composed of a plurality of chips arranged in a predetermined direction (x direction), and the individual chips are staggered in the y direction intersecting the x direction so as to provide a connecting region d having a predetermined width. Arranged while shifting.

  In FIG. 6A, the recording heads of the respective colors are arranged at the same position in the x direction. On the other hand, in FIG. 5B, the recording heads of the respective colors are arranged shifted in the x direction. That is, in the recording head having the configuration shown in FIG. 6A, the connecting regions of the respective colors appear at the same position on the recording medium, whereas in the recording head having the configuration shown in FIG. Appear in different positions. The recording head employed in this embodiment may have any of the configurations shown in FIGS. 6 (a) and 6 (b).

  FIGS. 7A to 7C are diagrams for explaining the difference in the recording method between the connecting part and the non-connecting part constituted by two chips (chip A and chip B). Referring to FIG. 7A, chip A and chip B each have 24 discharge ports for simplicity, and each discharge port has the same interval (one pixel area width) in the x direction. ). Chip A and chip B are arranged side by side as shown in the figure in a state where an overlapping region is provided in the x direction by a distance corresponding to four ejection ports. By providing the overlapping area, even if a slight arrangement error occurs between the chip A and the chip B at the time of manufacturing the recording head, an area in which no dot is recorded is not generated (white streak) between them. I can do it.

  When the recording medium is conveyed in the y direction while ejecting ink from the connecting head as shown in FIG. 7A, the width of one pixel region continuous in the y direction corresponding to the non-connecting portion A is equal to one included in the chip A. Recording is possible only at the discharge port. Further, the width of one pixel region continuous in the y direction corresponding to the non-connecting portion B can be recorded only by one ejection port included in the chip B. On the other hand, the width of one pixel region continuous in the y direction corresponding to the connecting portion can be recorded by two ejection ports included in each of the chip A and the chip B.

  FIG. 7B is a diagram showing the relationship between the position of each ejection port and the recording allowance of a chip including each ejection port. The horizontal axis indicates the positions of the individual discharge ports arranged from chip A toward chip B, and the vertical axis indicates the recording allowance of each chip. Here, with reference to FIG. 4 again, the print allowance rate refers to the print (1) data determined by the halftone processing unit 23, and the mask processing unit 24 sends the print data to the individual ejection ports (printing elements). As a result of the sorting, the ratio of each chip that is actually allowed to be recorded is shown.

  For example, since each one pixel area width corresponding to the non-connecting portion can be recorded by only one chip, the recording allowance of one chip is 100% and the recording allowance of the other chip is 0%. ing. On the other hand, since the width of one pixel area corresponding to the connecting portion can be recorded alternately by the two discharge ports of the chip A and the chip B, the recording allowable rate is 50% in both chips here. Yes.

  On the other hand, FIG. 7C shows an example in which the recording allowance ratios of the chip A and the chip B are made different depending on the position of the width of one pixel region in the connecting portion. According to this example, in the joint portion of the chip A, the recording allowance rate is lower as the ejection port is located closer to the chip B. Further, at the connecting portion of the chip B, the discharge allowance becomes lower as the ejection port is located closer to the chip A. In the same one pixel area, the sum of the recording allowances of chip A and chip B is 100%. As described above, the mask processing unit 24 can distribute the recording data to the chip A and the chip B with various recording allowance rates. Whatever the recording allowance ratio, the sum of the recording allowance ratios of chip A and chip B for one pixel area is set to 100% in both the connecting portion and the non-connecting portion. It is possible to record dots without excess or deficiency.

  However, there is a slight difference in the recording configuration between the connection portion and the non-connection portion. As a result of intensive studies, the present inventors have elucidated the mechanism by which the difference in the recording configuration between the connecting portion and the non-connecting portion varies the degree of bronze. Hereinafter, such a mechanism will be described step by step.

  8A to 8C are schematic cross-sectional views for explaining how ink droplets ejected from a recording head land on a recording medium in a normal state. Ink droplets 411 ejected from one ejection port of the recording head travel toward the recording medium 414 as shown in FIG. The ink droplets that have arrived on the surface of the recording medium gradually penetrate into the ink receiving layer 412 as shown in FIG. 4B, and all the ink droplets are absorbed as shown in FIG. The ink penetration process is complete.

  At this time, the coloring material and the solvent in the ink behave slightly differently in the penetration. Most of the color material (dye or pigment) in the ink liquid is adsorbed on the particles constituting the ink receiving layer 412 on the surface layer of the recording medium 414 and stays there, contributing to color development. A part of the color material reaches the base material 413 located below the ink receiving layer 412, but such a color material does not affect the color development so much. On the other hand, the solvent in the ink liquid passes through the fixing region of the color material and spreads to a lower layer than the ink receiving layer 412 or diffuses further to the periphery of the color material even in the surface layer, but then evaporates. As a result, the color density of the color material located on the surface layer is further improved as compared with the ink liquid state as the solvent evaporates. Thus, in ink jet recording, fixing is completed by landing of ink droplets 411, adsorption of a coloring material on the surface of the paper surface, and diffusion and evaporation of a solvent.

  FIGS. 9A to 9C are diagrams for explaining a difference between fixing that does not generate bronze and fixing that generates bronze although the same ink is used. FIG. 9A is a cross-sectional view and a top view showing a fixed state of cyan ink droplets as a result of normal landing as described in FIGS. 8A to 8C. In the figure, most of the fixed cyan color material is adsorbed to the ink receiving layer 412 of the recording medium, but a part reaches the base material 413 located below the ink receiving layer 412. When the recording surface is irradiated with white light 401 obliquely as shown in the figure, the cyan color material located in the ink receiving layer 412 absorbs light in the red region, so that the reflected light 402 becomes cyan.

  On the other hand, FIG. 9B is a cross-sectional view and a top view showing a fixing state when a large amount of cyan ink droplets are landed compared to the case of FIG. When a large amount of ink droplets land at a time, a relatively large amount of cyan coloring material reaches not only the ink receiving layer 412 but also the base material 413. Since the base material 413 cannot adsorb as much color material as the ink receiving layer, a large amount of color material stays in the ink receiving layer 412, and the color material density in the region increases as the solvent evaporates. Agglomerate. Such aggregation of the color material is unlikely to occur if the permeation rate in the ink receiving layer 412 is sufficiently rapid. However, as shown in FIG. 9B, when an amount of ink exceeding the capacity of the ink receiving layer 412 is landed in a short time, the speed at which the color material aggregates is superior to the penetration speed in the ink receiving layer. Aggregation is promoted. When the recording surface is irradiated with white light 401 as shown in the figure, the cyan color material positioned in the ink receiving layer 412 does not sufficiently absorb the light in the red region. As a result, the reflected light 425 becomes reddish purple light having a hue out of cyan, and is visually confirmed as bronze. That is, bronze is considered to be a phenomenon that occurs when the aggregation rate of the color material on the recording medium exceeds the absorption rate.

  FIG. 10 is a diagram illustrating an example of a color measurement method in the optical measuring device 820 for determining the degree of bronze that can be employed in the present embodiment. White light 401 is emitted from the light source 400 to the measurement target recording 404 at an incident angle of 45 °, and reflected light 403 from the recording 404 is received by the sensor 402. In this example, the sensor 402 is arranged in a direction perpendicular to the recorded matter 404 (0 °). When the ink recorded on the surface of the recorded matter 404 absorbs a predetermined wavelength of the white light 401, the color of the light detected by the sensor 402 changes. In addition, although the example of the 45/0 type | mold measuring method was shown in FIG. 10, it is good also as a 0/45 type | mold measuring method, adjusting the angle of irradiation and a detection according to the detection sensitivity of bronze, The degree of bronze can be obtained from the results of irradiation and detection.

  Although bronze is a phenomenon well known to those skilled in the art, its detection method is not particularly defined. Therefore, if a detection result that follows visual recognition is obtained, a method other than the colorimetry shown in FIG. 10 can be adopted. For example, the glossiness and image clarity of the surface of the recorded material may be measured, and the bronzing degree may be acquired from this.

FIG. 9C is a diagram showing the result of colorimetry of the image recorded as shown in FIGS. 9A and 9B by the method shown in FIG. In the figure, the straight line indicates the cyan hue range on the a ^* b ^* plane, the coordinate 426 is the color measurement result when the cyan ink droplet is normally landed as shown in FIG. 9A, and the coordinate 427 is the same. The color measurement results when landing is performed as shown in FIG. The coordinates 426 of the image in which normal landing is performed and bronze is not confirmed are on the cyan hue (straight line). On the other hand, the coordinates 427 of the image in which aggregation occurs and bronze is confirmed are at positions deviating from the cyan hue in the red direction. Here, the color difference between the two is indicated by 428.

  In the above description, the case where there are many ink droplets on the paper surface and the case where there are few ink droplets has been explained as being different in the degree of bronze. However, the case where two dots are recorded next to each other is recorded. But the appearance of bronze is different.

  FIGS. 11A to 11C illustrate how the difference in bronze appears when two cyan ink droplets are recorded at adjacent positions on the recording medium and when they are recorded at the same position. FIG. FIG. 11A is a cross-sectional view and a top view showing a fixing state when two cyan ink droplets are recorded at adjacent positions. In this case, the two ink droplets are fixed in the same manner as in FIG. Therefore, even when this recording surface is irradiated with white light 401, as in FIG. 9A, the cyan color material positioned in the ink receiving layer 412 absorbs light in the red region, and the cyan reflected light 402 is generated. can get.

  On the other hand, FIG. 11B is a cross-sectional view and a top view showing the fixing state when two cyan ink droplets are overlapped and recorded at the same position. When two ink droplets are recorded at the same position, if the timing of applying these two ink droplets is almost the same, a result similar to the case of FIG. 9B in which a large number of ink droplets are landed at once is obtained. can get. That is, many color materials aggregate in the ink receiving layer 412 and bronzing is confirmed. When this recording surface is irradiated with white light 401, the reflected light 425 becomes magenta light having a hue deviating from cyan.

  FIG. 11C is a diagram showing the result of colorimetric measurement of the recorded image as shown in FIGS. As in the case of FIG. 9C, the coordinates 420 of the image in which two dots are recorded without overlapping and bronzing is not confirmed are on the cyan hue (straight line). On the other hand, the coordinates 421 of the image in which two dots are recorded in duplicate and agglomeration occurs and bronzing is confirmed are at a position deviating from the cyan hue in the red direction. In this way, even when the same number of dots are recorded, the degree of bronze changes depending on the recording position, that is, the dot overlap rate (= the ratio of the total area of the dot overlap areas in the unit area).

  FIGS. 12A to 12D are diagrams for explaining a state in which the degree of bronzing, that is, the degree of hue shift differs depending on the overlap rate when four cyan dots are printed. FIG. 12A is a top view when four dots are recorded without overlapping at all, FIG. 12B is a top view when four dots are recorded with some overlap, and FIG. FIG. 10 is a top view when four dots are recorded while being relatively overlapped. FIG. 12D is a diagram showing the result of colorimetric measurement of the recorded images as shown in FIGS. As shown in FIG. 12A, the coordinates 451 of an image recorded without overlapping four dots are on the cyan hue (curve) when recording is performed so that dot overlap does not occur. On the other hand, as shown in FIGS. 12B and 12C, the coordinates 452 and 453 of the image recorded while the four dots overlap are located at positions deviating from the cyan hue in the red direction, and the overlapping area. The larger the is, the larger the amount of deviation is.

  Based on the above, the present inventors have found that in the connecting head, the difference in the dot overlap rate as described above between the connecting part and the non-connecting part causes bronze unevenness. I found it.

  As already described with reference to FIG. 7, recording is performed with only one chip in the region corresponding to the non-joining portion, but recording is performed with two chips in the region corresponding to the joining portion. Therefore, if an arrangement error occurs in the positional relationship between these two chips at the time of manufacturing, the arrangement relationship between dots recorded by these two chips is destroyed, and the dot overlap rate is affected.

  FIGS. 13A and 13B show the arrangement state on the recording medium of a plurality of dots recorded by these two chips when a manufacturing error occurs in the positional relationship between the chip A and the chip B shown in FIG. FIG. Here, a case where the chip B is arranged to be inclined with respect to the chip A is shown, FIG. 13A is a group of dots recorded by a non-joining portion of the chip A, and FIG. The dot groups recorded by the connecting portion of B are shown respectively. In FIG. 13 (a), it can be seen that nine dots recorded by the same chip A are arranged at a constant interval corresponding to the resolution of the recording apparatus and are recorded without overlapping each other. On the other hand, in FIG. 13B, a position shift occurs between the five dot groups recorded on the chip A and the four dot groups recorded on the chip B, and there are portions where the dots overlap. It can be seen that it is occurring in some places.

  As already described with reference to FIGS. 8 and 12, the degree of bronze in an image tends to stand out as the dot overlap rate increases. Therefore, in the case of this example, bronze is more conspicuous in FIG. 13 (b) recorded at the connecting portion than in FIG. 13 (a) recorded at the non-connecting portion.

  By the way, the dot overlap rate affecting the bronze changes not only by the positional deviation between the chips but also by the value of the recording data, that is, whether it is a high density area or a low density area. In other words, the appearance of bronze changes depending on the recording data (recording density) even in the case of an image recorded at the connecting part of two chips arranged so as to be shifted from each other.

  FIGS. 14A to 14E show how the bronze appears when the recording duty (recording density) of cyan ink is changed in various ways and when there is no recording position deviation. It is a figure for comparing with the case where it recorded in the state.

  FIG. 14A is a diagram comparing the dot recording state when the recording duty is 12.5% (recording rate 2/16) with and without the recording position deviation. At a recording rate of about 2/16, a small number of dots are recorded sparsely, so even if the positional relationship of the dots slightly changes due to the placement error between the chips, it hardly affects the overlapping area of the dots. No. That is, bronzing unevenness hardly occurs at an extremely low recording duty (highlight portion).

  FIG. 14B is a diagram comparing the dot recording state when the recording duty is 25% (recording rate 4/16) with and without the recording position deviation. At a recording rate of about 4/16, the dot overlap area slightly increases as shown in the figure when the positional relationship of the dots changes due to the placement error between the chips. That is, as compared with the highlighted portion shown in FIG. 5A, the bronzing unevenness caused by the placement error between the chips becomes more conspicuous.

  FIG. 14C is a diagram comparing the dot recording state in the case where the recording duty is 50% (recording rate 8/16) with and without the recording position deviation. At a recording rate of about 8/16, when the positional relationship of dots changes due to an arrangement error between chips, the overlapping area of dots greatly increases as shown in the figure. That is, the bronze unevenness due to the placement error between the chips becomes more conspicuous than in the case of FIG.

  FIG. 14D is a diagram comparing the dot recording state when the recording duty is 100% (recording rate 16/16) with and without the recording position deviation. When the recording rate is about 16/16, a large number of dots are recorded at a high density. Therefore, even if there is no arrangement error between chips, the overlapping area of dots is originally large, and a certain amount of bronzing occurs. ing. Even if the positional relationship between dots changes due to an arrangement error between chips, the area of the overlapping region of dots does not change significantly, and the degree of bronze does not change. That is, the bronzing unevenness caused by the placement error between the chips is rather inconspicuous as compared with the cases of FIGS.

FIG. 14E is a diagram in which the locus of the color when the cyan ink recording duty is changed is plotted in the a ^* b ^* coordinate system, and is recorded as shown in FIGS. It is a figure for comparing the result of having measured the color of an image with and without a recording position shift. In the figure, a locus accompanying an increase in recording duty in a state where there is no recording position deviation is indicated by a solid line, and a locus in a state where there is a recording position deviation is indicated by a dotted line. Comparing these two trajectories in order from the region with the lowest recording duty, first, in the highlight portion where the recording duty is low, the two almost coincide. As the recording duty increases, these two trajectories move away from each other. This is because the dot overlap rate associated with the recording position deviation increases as the recording duty increases, and bronzing becomes more conspicuous. Reference numeral 443 indicates the coordinates of the recording duty at which the two tracks are most distant from each other, and such recording duty is hereinafter referred to as a bronze maximum color.

  Even when the recording position shift occurs, since the dot overlap occurs to some extent, the degree of bronze is the same, and the coordinates are almost the same regardless of the presence or absence of the recording position shift.

  As a result of intensive studies, the present inventors have found that in an ink jet recording apparatus using a connecting head, the bronzing unevenness in the connecting portion and the non-connecting portion in the middle density portion is more serious on the image than in the high density portion. Judged to be. In such a situation, in order to suppress the bronze itself in the high density portion mainly, in the configurations of Patent Document 1 and Patent Document 2 in which the ink that does not easily cause bronzing is applied to the area that is easily recorded with the ink that easily causes bronzing, The above problem cannot be solved. In view of the above, the present inventors suppress agglomeration of coloring materials that cause bronze in the recording duty in the vicinity of the maximum bronze color in order to suppress bronze unevenness without damaging the hue of the entire image as much as possible. It was thought that applying ink was effective.

  Hereinafter, the effect of suppressing the aggregation (bronze) of the coloring material by additionally applying the ink that does not easily generate bronze to the recording position of the ink that easily generates bronze will be briefly described.

  FIGS. 15A to 15C are diagrams for explaining a fixing state when yellow ink (second ink) that hardly aggregates is recorded in a region where cyan ink (first ink) that easily aggregates is recorded. FIG. In general, in a recording medium provided with an ink receiving layer, the color material of the ink recorded in advance is likely to be adsorbed on the surface of the receiving layer, and the ink to be subsequently recorded passes through the adsorbing area. If it cannot be adsorbed, it tends to wrap around the lower layer.

  FIG. 15A is a cross-sectional view showing a state where ink droplets have landed on the same position of the recording medium in the order of cyan → yellow → cyan. In this case, in the recording medium, layers as shown in the figure are formed in the order of cyan layer 471 → yellow layer 472 → cyan layer 473. The yellow ink recorded after the cyan layer 471 formed in advance reduces the density of the cyan color material in the cyan layer 471 and inhibits aggregation. The cyan ink that is subsequently recorded must move a relatively long distance in the vertical and horizontal direction to the outside of the yellow layer 472 formed in advance, and the cyan color material contained therein is also aggregated. It is suppressed. Even if agglomeration (bronze) 424 occurs, it exists in the deep layer of the recording medium and does not contribute to color development. Therefore, compared to the case of FIG. 11B in which two cyan ink droplets are recorded at the same position, it is possible to obtain a color with reduced influence of bronze.

  FIG. 15B is a cross-sectional view showing a state where ink droplets have landed on the same position of the recording medium in the order of cyan → cyan → yellow. In this case, until yellow is recorded, cyan color material aggregation (bronze) 424 is generated as in FIG. 11B in which two cyan ink droplets are recorded at the same position. However, the yellow ink applied last penetrates the agglomerated 424 while being pushed deeper from the surface to form a yellow layer 476. Therefore, it is possible to obtain a color that is less affected by bronze than in the case of FIG.

  FIG. 15C is a cross-sectional view showing a state where ink droplets have landed on the same position of the recording medium in the order of yellow → cyan → cyan. In this case, the recording medium is formed with layers as shown in the order of yellow layer 477 → cyan layer 478 → cyan layer 479. The cyan ink recorded after the yellow layer 477 formed in advance must travel a relatively long distance in the vertical and horizontal directions to the outside of the yellow layer 477, and the cyan color material contained therein Aggregation is also suppressed. Even if agglomeration (bronze) 424 occurs, it exists in the deep layer of the recording medium and does not contribute to color development. Therefore, compared to the case of FIG. 11B in which two cyan ink droplets are recorded at the same position, it is possible to obtain a color with reduced influence of bronze.

  As described above, even in a situation where bronze is generated by cyan alone, by adding yellow ink to the same position, it is possible to suppress aggregation of cyan color material or keep it away from the surface, so that bronzing It can be inconspicuous. At this time, it is sufficient that the timing for applying yellow is close to the timing for applying cyan, and the effect can be obtained in any of the three examples described above.

  As described above, in the present invention, in order to suppress bronzing unevenness without impairing the hue of the entire image, an ink that suppresses aggregation of the coloring material that causes bronze is provided in the recording duty near the maximum bronze color. To do. That is, referring to FIG. 11 again, in the vicinity of the maximum bronze color 443, ink that hardly aggregates is applied. Here, in this embodiment, it is assumed that the ink that easily aggregates, that is, easily causes bronzing, is cyan ink. In addition, it is assumed that ink that hardly aggregates, that is, ink that does not easily cause bronzing, is gray, magenta, and yellow ink.

  Hereinafter, specific examples of an image processing method that can be used in the recording apparatus of the present embodiment for reducing bronzing while utilizing the above-described effects will be described.

  FIG. 16 is a diagram illustrating a general relationship between cyan multi-value data and recording duty in a recording medium. The horizontal axis indicates cyan multi-value data generated by the color separation processing 22, and it is assumed here that a value of (0-255) corresponding to 8 bits can be taken. The vertical axis represents the recording duty (recording density) of each color dot actually recorded on the recording medium in correspondence with each multi-value data in percent. Normally, as shown in FIG. 16, the recording duty of cyan ink increases in proportion to the multi-value data of cyan, and the recording duty of other inks (magenta, yellow, gray) remains 0%.

  On the other hand, FIG. 17 is a diagram showing the relationship between cyan multivalued data and recording duty in the first embodiment. In this embodiment, the recording duty of magenta, yellow, and gray is increased up to 5% within the range of 150 to 224 of cyan multi-value data. When cyan multivalued data is 192, the cyan recording duty is about 75%, and the bronze maximum color described in FIG. 14 is obtained. Therefore, in this embodiment, the largest amount (5%) of ink that hardly aggregates with the maximum color of bronze is recorded. However, the recording duty of 5% is not particularly limited. These three color inks only need to sufficiently reduce the aggregation of the cyan color material to such an extent that the bronzing unevenness is not noticeable, and this value is preferably adjusted appropriately according to the state.

  As described above, when ink of another hue is applied to an area where only cyan multi-value data actually exists, there is a risk that the hue of cyan will be shifted somewhat on the image. However, in this embodiment, magenta, yellow, and gray are given little by little to achieve hue balance, and the recording duty of such ink is gradually increased or decreased in the range of 150 to 224 of multi-value data. . As a result, it is possible to prevent the cyan hue in the maximum bronze color from deviating extremely compared to other gradations.

  In the present embodiment, the control as described above is performed by the color separation conversion unit 22 shown in FIG. That is, even if the color separation table 20 of this embodiment is an RGB signal that is normally converted to CMYKGy (192, 0, 0, 0, 0), this signal is, for example, CMYKGy (192, 12, 12). , 0, 12), the data is stored. Then, the color separation conversion unit 22 sends the data converted using such a table to the halftone processing unit 23, whereby magenta, yellow, and gray inks are recorded 5% each in the cyan image on the recording medium, and bronze An image with reduced unevenness is obtained.

  In Example 1, the other color ink is applied only in the vicinity of the bronze maximum color. On the other hand, in the present embodiment, ink of other colors is applied in all gradations that may cause dot overlap due to a recording position shift that causes bronze unevenness while including the maximum bronze color.

  As already described with reference to FIGS. 14A to 14E, the hue shift associated with the bronze does not occur in the highlight portion, and more or less occurs in the other regions to some extent. In the recording apparatus of the present embodiment, referring to FIG. 14E, the hue shift accompanying bronze starts to appear at a recording duty of about 25%. Therefore, in the second embodiment, ink of other colors is applied with a recording duty of 25% or more.

  FIG. 18 is a diagram illustrating the relationship between cyan multivalued data and the recording duty of each ink color in the second embodiment. In this embodiment, the recording duty of magenta, yellow, and gray is gradually increased from 64 of cyan multi-value data, and the print duty is maintained at 5% for multi-value data 96 and higher. The cyan multi-value data 64 is multi-value data corresponding to the recording duty of 25% shown in FIG.

  In this embodiment, ink is applied to data of (R, G, B) = (255, 255, 255). This means that if ink is not applied to the data area, ink dots are not visible only in this area, and the graininess is better than other areas. However, when the graininess is generally uniform, it may appear visually smooth, so that ink is applied to the data of (R, G, B) = (255, 255, 255). did.

  Also in this embodiment, the control as described above can be performed by the color separation conversion unit 22 shown in FIG. 4 as in the first embodiment. The color separation conversion unit 22 sends the data converted using the table for realizing the signal values as shown in FIG. 18 to the halftone processing unit 23, so that magenta, yellow, and gray inks are 5 in the cyan image on the recording medium. Recorded in%. As a result, a cyan image with reduced bronze unevenness is obtained.

  FIGS. 19A and 19B are diagrams showing the relationship between cyan multivalued data and the recording duty of each ink color in Example 3. FIG. In both cases, the multi-value data of cyan, which is the largest color of bronze, is 192, and the print duty is smoothly increased and decreased in a wider area than in the first embodiment while the print duty of magenta, yellow and gray inks is maximized. Further, in accordance with the increase / decrease in the recording duty of magenta, yellow, and gray inks, the recording duty of cyan ink is slightly changed in this embodiment. Specifically, as can be seen from the figure, the convex shape is such that the multi-value data becomes a vertex at 192. By adopting such a shape, it is possible to avoid a decrease in the saturation of cyan in the maximum bronze color and the accompanying deterioration in gradation. FIG. 19A shows an example in which magenta, yellow, and gray inks are recorded from multi-value data 64 corresponding to a recording duty of 25%, as in the second embodiment. FIG. 19B shows an example in which magenta, yellow and gray inks are recorded from multi-value data 96 larger than this. In any case, the data value for starting the application of magenta, yellow, and gray ink and the recording duty that becomes the peak in the maximum bronze color are appropriately adjusted to such an extent that the unevenness of the bronze due to the recording position deviation is not noticeable It ’s fine.

  In the first to third embodiments described above, the description is focused on the area where only the cyan ink is normally used, that is, the gradation area from white to cyan. However, it is a matter of course that the cyan ink which easily causes aggregation is used. It's not just an area. In the following, a method for reducing bronzing unevenness including other color areas using cyan ink will be described.

FIG. 20 is a diagram showing color regions (color solids) that can be expressed by the recording apparatus of the present embodiment in the L ^* a ^* b ^* space. The recording apparatus according to the present embodiment can express the colors in the solid shown in the figure by adjusting the ink application amounts of cyan, magenta, yellow, black, and gray, respectively. In the figure, the straight line from white to cyan corresponds to the horizontal axis in FIGS. 17 and 18, and the point Q indicates the coordinate (the bronze maximum color) where bronzing is most likely to occur due to aggregation of cyan color materials. Further, a region in which cyan color material is aggregated due to dot overlap and bronze is a concern is indicated by gradation around the point Q together with the degree of bronze. As can be seen from the figure, the area where bronze is a concern extends beyond the straight line from white to cyan, as well as the green and blue areas.

  For the surface formed by three points of white, cyan, and green, in the color separation process, conversion is performed such that yellow multi-value data increases as it goes from cyan to green. That is, the amount of yellow ink applied increases from cyan to green regardless of the bronze reduction process. Similarly, for the surface formed by three points of white, cyan, and blue, in the color separation process, conversion is performed so that the multi-value data of magenta becomes larger from cyan to blue. That is, the amount of magenta ink applied increases from cyan to blue regardless of the bronze reduction process. Therefore, a certain degree of bronzing suppression effect is obtained in advance in such a region even without applying ink for reducing bronzing. Therefore, ink for reducing the bronze may be applied to such a region by an amount that is insufficient to obtain a sufficient bronze suppressing effect. That is, for the white, cyan, and green surfaces, the amount of magenta, yellow, and gray imparted to reduce bronzing may be gradually decreased from cyan to green. For the white, cyan, and blue surfaces, the amount of magenta, yellow, and gray imparted to reduce bronze may be gradually decreased from cyan to blue. By preparing a color separation table 20 that realizes such a given amount in advance, in the color region centered on the bronze maximum color Q, the unevenness of bronze is reduced without extremely shifting the hue. A uniform image can be output.

  In the fourth embodiment, a case where magenta and yellow inks are likely to aggregate in each color material in addition to cyan ink will be described.

  FIG. 21 is a diagram illustrating the relationship between cyan multivalued data and the recording duty of each ink color in the fourth embodiment. In this embodiment, cyan, magenta, yellow, and gray inks are recorded at 5% each at the point where the multivalue data of cyan is 0, that is, at the white point shown in FIG. For cyan ink, the recording duty is linearly increased in the range of 5% to 100% as multi-value data rises. For magenta, yellow, and gray inks, 5% Maintain recording duty. Such a configuration is similarly applied to a range from white to magenta and a range from white to yellow. That is, in the range from white to magenta, the magenta recording duty is linearly increased in the range of 5% to 100% as the multi-value data of magenta rises. On the other hand, for cyan, yellow, and gray inks, a recording duty of 5% is maintained throughout the magenta multi-value data. In the range from white to yellow, the yellow recording duty is linearly increased in the range of 5% to 100% as the multi-value data of yellow increases. On the other hand, for cyan, magenta, and gray inks, a printing duty of 5% is maintained throughout the multi-value data of yellow.

  When bronzing is a concern for the three colors cyan, magenta, and yellow, the ink of each color is already recorded at a point slightly deviated from the white point, and the graininess of dots in the highlight portion of each color. There is also a concern. However, as in this embodiment, if a certain amount of dots are recorded even with perfect white, the difference in graininess between white and highlight portions can be reduced. As a result, it is possible to maintain smooth gradation while suppressing bronzing unevenness in all color regions.

  In the above, the bronzing unevenness suppressing effect has been described mainly in the region from white to cyan, magenta or yellow. However, there is a concern in the region from black to each color.

  22A to 22D are diagrams showing the relationship between cyan multi-value data and the recording duty of each ink color from white to cyan and from black to cyan. FIG. 22A is a diagram showing a general relationship between multi-value data from white to cyan and the recording duty, as in FIG. On the other hand, FIG. 22B is a diagram showing a general relationship between multi-value data from black to cyan and recording duty. In the area from black to cyan, the cyan recording duty is 100% in all areas. On the other hand, the recording duty of magenta, yellow and gray inks linearly decreases from 100% to 0% from black to cyan regardless of the bronze suppression effect.

  In contrast to such a general color conversion process, FIGS. 22C and 22D show the recording duty of each ink color for realizing the bronze suppression effect in this embodiment from white to cyan and from black to cyan. FIG. FIG. 22C shows a state in which magenta, yellow, and gray inks are recorded by 5% in the entire region in order to suppress the cyan ink bronzing unevenness in the region from white to cyan. Accordingly, the recording duty of cyan ink is set to 5% even in white, and the recording duty is linearly increased in the range of 5% to 100% in all regions. That is, the diagram shown in FIG. 22C is the same as FIG. 21 described in the fourth embodiment.

  On the other hand, FIG. 22D shows a state in which the recording duty of magenta, yellow, and gray inks is not set to 0% in the entire region in order to suppress the cyan ink bronze unevenness in the region from black to cyan. . In this embodiment, in order to suppress aggregation of the cyan color material, the recording duty of magenta, yellow and gray inks is set to 5% instead of 0% even at the position closest to cyan. The recording duty of these inks is gradually changed so as to linearly decrease between 100% of black. In this embodiment, the recording duties of the inks of the respective colors are the same in the region from the most cyan in both FIGS. 22 (c) and 22 (d). That is, according to the present embodiment, smooth gradation can be realized while suppressing unevenness of bronze in the gradation change from white to cyan to black. Further, by applying such a configuration in the magenta and yellow directions in the same manner, it is possible to output a uniform image without uneven bronzing in the entire area of the color solid shown in FIG.

(Other embodiments)
In the above embodiment, the example in which the recording duty is 75% and the maximum bronze color is described with reference to FIG. 14, but the present invention is not limited to such a state. As described with reference to FIG. 14, the bronze maximum color is a recording duty that maximizes the change in the dot overlap rate due to the recording position shift, and thus the value is the type of the recording medium, the ejection amount of the recording head, and the type of ink. It changes by etc. Regardless of the recording duty at which the change in the dot overlap rate is maximized, if the ink for suppressing aggregation is additionally recorded as in the above-described embodiment within the range including the region, the above-described case may occur. The effects of the present invention can be obtained. However, as a result of specific examinations by the present inventors, since the change in the dot overlap rate is often the largest when the recording duty is about 75% to 80%, the maximum bronze is 75% in the above embodiment. It was explained with an example of color.

  In the above, the case where the cyan color material has a strong tendency to agglomerate and the bronze is easily noticeable in the cyan image has been described as an example. However, the present invention is not limited to such an ink. The types and combinations of inks are not limited to the above-described compositions, and various ink compositions can be employed. For example, as a color material, not only a dye but also a pigment can be employed. In order to weaken the aggregation of the coloring material, counter ions (Li +, K +) or cationic additives can be added to the ink in advance.

  In the above description, the ink having the strongest tendency to aggregate has been described as the cyan ink. However, the present invention is not limited to such a state. The ink having the strongest tendency to agglomerate may be magenta or yellow, and the same effect can be obtained by applying the control for the cyan ink described above to these inks.

  Further, the combination of inks applied to suppress bronzing is not limited to the above embodiment. The ink applied to suppress the aggregation of the cyan ink may be other single color ink alone or a plurality of combinations including black. However, it is effective to select ink colors with a balanced combination in the color space in order to avoid as much as possible hue shift due to the application of the bronze suppression ink. From this point of view, in order to suppress the bronze of cyan ink, it is preferable to use a combination of inks that are complementary to cyan, such as magenta and yellow, or an achromatic ink such as gray or black. However, for black ink, the graininess may be too conspicuous, so it is preferable to use gray ink instead of black ink at least in the highlight area.

  Further, increasing the type of ink applied to suppress bronzing is also effective for ensuring the effect of reducing bronzing unevenness. As described above, the degree of unevenness of bronze is affected by the mounting error of each chip in the recording head, but such an arrangement error between chips also exists between different color inks. That is, even if an attempt is made to record ink for suppressing aggregation at the landing position of ink that tends to aggregate, there may be situations where these two colors of ink are not landed at the same position. Even in such a case, if a plurality of types of ink for suppressing aggregation are recorded toward the landing position of the ink that easily aggregates, the possibility that any of the inks will land on the target position increases. In addition, the aggregation suppressing effect can be further ensured.

  In the above-described embodiment, an example of an ink jet recording apparatus that discharges inks of five colors of cyan, magenta, yellow, black, and gray has been described as an example. It is not limited to. For example, a light cyan ink or light magenta ink having a low color material density may be prepared in order to further reduce graininess. In this case, if light cyan ink or light magenta ink is used more positively as ink to be applied to suppress aggregation, it is possible to further reduce graininess when suppressing bronzing unevenness. Further, if light cyan ink is used to suppress cyan ink aggregation and light magenta ink is used to suppress magenta aggregation, hue deviation due to the application of bronze suppression ink can be more effectively avoided. I can do it.

  As an example of a form using light cyan and light magenta, in the case of the first embodiment, the recording duty of light cyan and light magenta is set in addition to magenta, yellow and gray in the range of 150 to 224 of cyan multi-value data. Increase up to 5%. In the second embodiment, the recording duty of light cyan and light magenta is gradually increased from 64 of cyan multi-value data in addition to magenta, yellow, and gray. For multi-value data 96 or more, the recording duty is 5%. Should be maintained. In the fourth embodiment, light cyan and light magenta are further recorded by 5% each at a point where cyan multi-value data is 0, that is, a white point, and light cyan and light magenta are recorded in the entire multi-value data. The recording duty may be maintained at 5%. In the fifth embodiment, magenta, yellow, and gray are used as inks having a bronze suppressing effect. However, light cyan and light magenta are added thereto, and the same control may be performed.

  Furthermore, the full-line type ink jet recording apparatus shown in FIG. 1 has been described above as an example, but the present invention is not limited to the ink jet recording apparatus having such a configuration. The connecting head as shown in FIGS. 6A and 6B can also be mounted on an ink jet recording apparatus configured to complete an image while alternately performing recording scanning and recording medium conveyance operation.

  In the above-described embodiment, the ink for controlling bronzing is controlled by the color separation table. However, the halftone processing unit may control binary data that records ink or not. For example, as shown in FIG. 20, when 5% of gray and yellow ink is applied to the entire color region, the color separation table is in a state where no bronze suppression ink is put as shown in (a) and (b). Instead, the halftone processing unit converts the data into binary data that determines recording (1) or non-recording (0) for each color so that gray and yellow ink corresponding to 5% is applied in the color separation table. . In this way, when ink is applied to suppress bronzing in the halftone part, when the color separation is designed with priority given to gradation and graininess and the maximum amount of ink that can be driven onto the recording paper surface, the optimum is achieved. There is an advantage that gradation and graininess can be realized.

20 color separation table
21 Resolution converter
22 Color separation conversion unit
23 Halftone processing section
24 Mask processing section
601 chips
602 Connecting head
610 recording head
810 Inkjet recording apparatus
811 Discharge port

Claims (8)

A plurality of discharge ports for discharging ink of the same color have a plurality of chips arranged in a predetermined direction, and a part of the plurality of chips arranged at one end of the first chip in the predetermined direction A discharge port and a part of the discharge ports arranged at an end portion on the first chip side in the predetermined direction of the second chip disposed at a position adjacent to the first chip in the predetermined direction; A recording head in which the plurality of chips are arranged in the predetermined direction so as to provide an overlapping portion capable of recording in the same area on the recording medium by being arranged in a crossing direction crossing the predetermined direction, The first recording head for ejecting the first color ink containing the color material having the colorant and the first having the property of suppressing aggregation of the color material contained in the first color ink. Ejects the second color ink different from the first color And a second of the recording head because by using a plurality of said recording head comprising at least an ink jet recording apparatus for recording an image on said recording medium,
Control means for controlling ejection of the second color ink in the second recording head;
When the color on the straight line from white to the first color in the L * a * b * space is reproduced on the recording medium, the overlapping portion of the first recording head causes the ink of the first color An image resulting from a relative recording position shift between the first chip and the second chip in the first recording head in the first area on the recording medium in which the amount to be applied is the first amount Is larger than the second area on the recording medium in which the amount of the first color ink applied by the overlapping portion of the first recording head is the second amount,
The control means has an amount that the second recording head applies the second color ink to the first area more than an amount that applies the second color ink to the second area. As described above, an ink jet recording apparatus that controls ejection of the second color ink. L * a * b * colors are on a straight line toward the first color from white when reproducing the recording medium in the space, the overlapping portion of the first recording head is of the first color ink The first amount, which is the amount to which the first recording head is applied, is a deviation in the coloring , wherein the color deviation is changed according to the amount of the first recording head to which the first color ink is applied. Of the largest amount of
Said control means, said amount of the second recording head applying ink of the second color, L * a * b * a color in a straight line toward the first color from white in space recorded The ink jet apparatus according to claim 1 , wherein the second recording head applies a maximum amount of the second color ink when reproduced on a medium . When the color on the straight line from white to the first color in the L * a * b * space is reproduced on the recording medium, the overlapping portion of the first recording head causes the ink of the first color The first amount, which is the amount to which the first recording head is applied, is a deviation in the coloring, wherein the color deviation is changed according to the amount of the first recording head to which the first color ink is applied. Of the largest amount of
To the number of the first color ink dots that can be recorded by the discharge of from the overlapping portion on the front type recording medium, the said first amount from the overlapping portion on the recording medium first The inkjet recording apparatus according to claim 1 or 2, wherein the ratio of the number of dots that can be recorded by discharging one color of ink is 75% to 80%.   4. The method according to claim 1, wherein the first color ink is a cyan ink, and the second color ink is any one of a yellow ink, a magenta ink, and a gray ink. The inkjet recording apparatus according to Item. The hue of the second color is the same as the hue of the first color, and the ink of the second color has a lower color material concentration than the ink of the first color. The inkjet recording apparatus according to any one of claims 1 to 3 . The plurality of recording heads has a property of suppressing aggregation of coloring materials contained in the first color ink, and ejects a third color ink different from the first and second colors. A third recording head;
When the color on the straight line from white to the first color in the L * a * b * space is reproduced on the recording medium, the overlapping portion of the first recording head causes the ink of the first color An image resulting from a relative recording position shift between the first chip and the second chip in the first recording head in the first area on the recording medium in which the amount to be applied is the first amount Is larger than the second area on the recording medium in which the amount of the first color ink applied by the overlapping portion of the first recording head is the second amount,
The control means is such that the amount that the third recording head applies the third color ink to the first region is larger than the amount that the third color ink is applied to the second region. The inkjet recording apparatus according to claim 1, wherein ejection of the third color ink is controlled. A plurality of discharge ports for discharging ink of the same color have a plurality of chips arranged in a predetermined direction, and a part of the plurality of chips arranged at one end of the first chip in the predetermined direction A discharge port and a part of the discharge ports arranged at an end portion on the first chip side in the predetermined direction of the second chip disposed at a position adjacent to the first chip in the predetermined direction; A recording head in which the plurality of chips are arranged in the predetermined direction so as to provide an overlapping portion capable of recording in the same area on the recording medium by being arranged in a crossing direction crossing the predetermined direction, The first recording head for ejecting the first color ink containing the color material having the colorant and the first having the property of suppressing aggregation of the color material contained in the first color ink. Ejects the second color ink different from the first color And a second of the recording head because by using a plurality of said recording head comprising at least an ink jet recording apparatus for recording an image on said recording medium,
Control means for controlling ejection of the second color ink in the second recording head;
When the color on the straight line from white to the first color in the L * a * b * space is reproduced on the recording medium, the overlapping portion of the first recording head causes the ink of the first color In the case where the degree of color development deviation of the image due to the relative recording position deviation of the first chip and the second chip in the first recording head changes in accordance with the amount to which the first recording head is applied, the control The means for discharging the second color so that the overlapping portion of the first recording head ejects a predetermined amount of the second color ink irrespective of the amount of the first color ink applied. An ink jet recording apparatus that controls the discharge of ink. A plurality of discharge ports for discharging ink of the same color have a plurality of chips arranged in a predetermined direction, and a part of the plurality of chips arranged at one end of the first chip in the predetermined direction A discharge port and a part of the discharge ports arranged at an end portion on the first chip side in the predetermined direction of the second chip disposed at a position adjacent to the first chip in the predetermined direction; A recording head in which the plurality of chips are arranged in the predetermined direction so as to provide an overlapping portion capable of recording in the same area on the recording medium by being arranged in a crossing direction crossing the predetermined direction, The first recording head for ejecting the first color ink containing the color material having the colorant and the first having the property of suppressing aggregation of the color material contained in the first color ink. Ejects the second color ink different from the first color And a second of the recording head because by using a plurality of said recording head comprising at least an ink jet recording method for recording an image on said recording medium,
A control step of controlling ejection of the second color ink in the second recording head;
When the color on the straight line from white to the first color in the L * a * b * space is reproduced on the recording medium, the overlapping portion of the first recording head causes the ink of the first color An image resulting from a relative recording position shift between the first chip and the second chip in the first recording head in the first area on the recording medium in which the amount to be applied is the first amount Is larger than the second area on the recording medium in which the amount of the first color ink applied by the overlapping portion of the first recording head is the second amount,
In the control step, the amount that the second recording head applies the second color ink to the first region is larger than the amount that the second color ink is applied to the second region. As described above, an ink jet recording method comprising controlling ejection of the second color ink.

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