JP2018122529A - Inkjet recording device and inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inkjet recording device that can output an uneven brightness-free and even image in multi-pass bidirectional recording, and to provide an inkjet recording method.SOLUTION: An inkjet recording device controls so that first recording scanning has a recording allowance rate that varies from that of the last recording scanning within the identical recording scanning of a plurality of times of recording scanning to a unit region. The inkjet recording device further controls the final recording scanning so that a recording rate in the beginning of the recording scanning is lower than a recording rate in the end of the recording scanning.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a multipass ink jet recording apparatus and an ink jet recording method for forming an image while a recording head that ejects ink is scanned on a recording medium.

  In a serial type color ink jet recording apparatus, uneven gloss may be a problem when pigment ink is used. Patent Document 1 discloses a recording method that adjusts the recording rate of each ink so that the ink appearing on the surface is unified in the image as much as possible in a configuration using high gloss ink and low gloss ink. ing. According to Patent Document 1, it is possible to substantially unify the overlapping order of high gloss ink and low ink recording medium over the entire area of the recording medium, and to reduce uneven gloss in the image.

Japanese Patent Laid-Open No. 2004-338312

  However, in Patent Document 1, control is performed so that an ink having a low glossiness is positioned as high as possible. For this reason, even when an image having high glossiness is required, only a low glossy image can be output, and the user's request may not be met.

  Further, uneven gloss may be confirmed even for a single color image using only one type of ink. For such uneven gloss, Patent Documents on the premise that a plurality of inks having different gloss levels are used. Even if the method 1 was adopted, it could not be sufficiently relaxed.

  The present invention has been made to solve the above problems. Therefore, an object of the present invention is to provide an ink jet recording apparatus and an ink jet recording method capable of outputting a uniform image without uneven gloss in multi-pass bidirectional recording.

  To this end, the present invention records an image in a unit area of the recording medium by a plurality of recording scans of the recording head by alternately scanning the recording head that discharges ink in the forward direction and the backward direction. In the inkjet recording apparatus, the generating unit that generates ejection data corresponding to each of the plurality of recording scans based on the image data corresponding to the unit area, the recording head with respect to the unit area, Recording means for executing the plurality of recording scans according to the ejection data, and the generating means is the same recording scan in the first recording scan and the last recording scan among the plurality of recording scans for the unit area. In the last recording scan, the recording rate at the beginning of the recording scan is smaller than the recording rate at the end. Kunar so on, and generates ejection data corresponding to each of the plurality of times of printing scans.

  According to the present invention, a uniform image without uneven gloss can be output in bidirectional multi-pass printing.

(A) And (b) is a schematic block diagram of an inkjet recording device. It is a block diagram which shows the structure of control in an inkjet recording device. It is a flowchart for demonstrating the process of the image processing which MPU performs. It is a schematic diagram for demonstrating 6-pass multipass printing. It is a figure for demonstrating the mask pattern generally used. (A) And (b) is a schematic diagram for demonstrating the cause of the difference in glossiness. It is a figure which shows the mask pattern used in 1st Embodiment. (A)-(c) is a figure which shows the example of the mask pattern which can be used. It is a figure which shows the effect at the time of employ | adopting the recording control of 1st Embodiment. It is a figure which shows the mask pattern used as a comparative example. It is a figure which shows the mask pattern which can be used as a modification of 1st Embodiment. It is a figure which shows the mask pattern used in 2nd Embodiment. It is sectional drawing of the state which provided the processing liquid on the ink layer.

(First embodiment)
FIG. 1A is a schematic configuration diagram of an ink jet recording apparatus 30 used in the present embodiment. A recording head 22 for ejecting ink and an ink tank 21 for supplying ink to the recording head 22 are detachably mounted on the carriage 1.

FIG. 1B is an enlarged view of the recording head 22 as viewed from the −z direction. The recording head 22 has six ejection port arrays for ejecting black (K), cyan (C), magenta (M), yellow (Y), light cyan (LM), and light magenta (LM) inks in the x direction. Are arranged in parallel. Each discharge port array 24 is configured by arranging 1248 discharge ports 23 at a pitch of 1200 dpi in the y direction (sub-scanning direction). The amount of ink ejected from each ejection port at a time is about 4.5 ng. The ink tank 21 is connected to the recording head 22 and individually stores ink to be supplied to each of the six ejection port arrays 24.

  Returning to FIG. The carriage 1 can reciprocate in the main scanning direction (x direction) while being guided and supported by the guide shaft 4 with the carriage motor 5 as a drive source. While the carriage 1 moves in the x direction, the recording head 22 ejects ink from the individual ejection openings 23 toward the recording medium S located below, whereby an image for one band is recorded on the recording medium S. The When the recording scan for one band is completed, the recording medium S is conveyed by a distance corresponding to the width of one band in the sub-scanning direction (y direction) intersecting the main scanning direction. An image is formed on the recording medium S stepwise by alternately repeating the main recording scan and the conveying operation as described above.

  At the home position in the apparatus, six caps 20 for individually capping the six ejection port arrays 24 arranged in the recording head 22 are provided. When the recording operation is not performed, the carriage 1 moves to the home position, and the recording head 22 receives various maintenance processes such as a capping operation.

  FIG. 2 is a block diagram showing a control configuration in the ink jet recording apparatus of the present embodiment. The image data generated by the host computer (image input unit) 28 is transmitted to the ink jet recording apparatus and recorded by the ink jet recording apparatus.

  Image data generated by an application of the host computer (image input unit) 28 is received by the inkjet recording apparatus 30 via the interface (I / F) 312. In the present embodiment, the image data received by the inkjet recording apparatus 30 is RGB multi-value data. In the figure, the host computer 28 is shown as an example, but the image input unit that can be connected to the inkjet recording apparatus 30 is not limited to this. An image input device such as a scanner or a digital camera can also be used as the image input unit.

  An MPU (Micro Processor Unit) 302 controls the entire apparatus according to a program stored in the ROM 304 while using the RAM 305 as a work area. The ASIC 303 is an integrated circuit that executes various processes at high speed under the instruction of the MPU 302. For example, when image data is received via the interface (I / F) 312, the MPU 302 stores it in the print buffer via the ASIC 303. The image data stored in the print buffer 306 is subjected to various image processing in accordance with the image processing program stored in the ROM 304 and various parameters, and multi-value RGB data is associated with each ink color (CMYKLcLm). Convert to binary data. Further, based on the binary data, according to the mask pattern stored in the mask buffer, ejection data corresponding to each recording scan and each ink color (each ejection port array 24) is generated and stored again in the print buffer 306. . The mask pattern stored in the mask buffer is read out by the MPU 302 according to the recording mode from among a plurality of mask patterns stored in the ROM 304 in advance. The series of image processing as described above will be described in detail later.

  When the ejection data corresponding to each recording scan and each ejection port array is generated, the ASIC 303 drives the recording head 22 via the recording head driver 311 and executes an ejection operation according to the ejection data. During the ejection operation, the ASIC 303 drives the carriage motor 5 via the carriage driver 308 to move the carriage 1 in the main scanning direction. When such a recording scan is completed, the ASIC 303 drives the conveyance motor 6 via the conveyance driver 309 to move the recording medium S in the y direction. At a predetermined timing when the recording operation is not performed, the ASIC 303 performs maintenance processing on the recording head 22 via the maintenance driver 310.

  FIG. 3 is a flowchart for explaining image processing steps executed by the MPU 302 using the ASIC 303. This process is started when RGB multi-value data (image data) is input from the host computer 28 and stored in the print buffer 306.

  When this processing is started, the MPU 302 performs color conversion processing on the image data stored in the print buffer 306 in step S801. Specifically, with reference to a three-dimensional lookup table stored in the ROM 304, RGB multi-value data is converted into CMYKLcLm multi-value data corresponding to ink colors used in the printing apparatus.

  Next, the MPU 302 performs binarization processing in step S802, and converts the multivalued data of CMYKLcLm into binary data of CMYKLcLm. As the binarization processing method, various known methods such as error diffusion processing and dither processing can be employed.

  In step S803, the MPU 302 uses the mask pattern stored in the print buffer for the binary data of CMYKLcLm, and generates ejection data corresponding to individual print scans in multipass printing. The details of the multipass printing and the mask pattern will be described later. Among the pixels that can be printed in one printing scan by the mask pattern processing in step S803, each ejection port array ejects ink from the pixel (1). Discharge data that defines a pixel (0) that is not discharged is generated.

  When ejection data corresponding to each printing scan is generated in step S803, the MPU 302 proceeds to step S804, and executes a printing operation according to the generated ejection data. That is, an image is recorded on the recording medium by alternately repeating a recording scan for causing the recording head 22 to execute an ejection operation according to the ejection data while moving the carriage 1 and a conveyance operation for conveying the recording medium S. This process is completed.

  Next, the components and manufacturing method of the ink used in the present embodiment will be described. Hereinafter, “parts” and “%” are based on mass unless otherwise specified.

(Black ink)
(1) Preparation of dispersion First, anionic polymer P-1 [styrene / butyl acrylate / acrylic acid copolymer (polymerization ratio (weight ratio) = 30/40/30) acid value 202, weight average molecular weight 6500] Prepared. This was neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a uniform 10% by mass polymer aqueous solution.

  100 g of the polymer solution, 100 g of carbon black, and 300 g of ion-exchanged water are mixed and mechanically stirred for 0.5 hour. The mixture is then processed using a microfluidizer by passing the mixture five times through the interaction chamber under a liquid pressure of about 70 MPa. Further, the dispersion obtained above is centrifuged (12,000 rpm, 20 minutes) to remove non-dispersed materials including coarse particles to obtain a black dispersion. The resulting black dispersion had a pigment concentration of 10% by mass and a dispersant concentration of 6% by mass.

(2) Preparation of ink Ink preparation uses the above black dispersion. The following components are added to this to give predetermined concentrations, and these components are sufficiently mixed and stirred, followed by pressure filtration with a micro filter (manufactured by FUJIFILM Corporation) having a pore size of 2.5 μm, and a pigment concentration of 5% by mass. A pigment ink having a dispersant concentration of 3% by mass is prepared.
Black dispersion 50 parts Glycerin 10 parts Triethylene glycol 10 parts Acetylene glycol EO adduct 0.5 parts (manufactured by Kawaken Fine Chemical Co., Ltd.) Ion-exchanged water 29.5 parts

(Cyan ink)
(1) Preparation of dispersion First, using benzyl acrylate and methacrylic acid as raw materials, an AB type block polymer having an acid value of 250 and a number average molecular weight of 3000 is prepared by a conventional method, and further neutralized with an aqueous potassium hydroxide solution. Diluted with ion-exchanged water to prepare a homogeneous 50% by weight polymer aqueous solution.

  180 g of the above polymer solution, C.I. I. 100 g of CI Pigment Blue 15: 3 and 220 g of ion-exchanged water were mixed and mechanically stirred for 0.5 hour.

  The mixture was then processed using a microfluidizer by passing it through the interaction chamber 5 times under a liquid pressure of about 70 MPa.

  Further, the dispersion obtained above was centrifuged (12,000 rpm, 20 minutes) to remove non-dispersed materials containing coarse particles to obtain a cyan dispersion. The obtained cyan dispersion had a pigment concentration of 10% by mass and a dispersant concentration of 10% by mass.

(2) Preparation of ink Ink preparation uses the above-mentioned cyan dispersion liquid, and the following components are added thereto to obtain a predetermined concentration. After sufficiently mixing and stirring these components, pressure filtration is performed with a micro filter (manufactured by Fuji Film Co., Ltd.) having a pore size of 2.5 μm to obtain a pigment ink having a pigment concentration of 2 mass% and a dispersant concentration of 2 mass%. Prepared.
Cyan dispersion 20 parts Glycerin 10 parts Diethylene glycol 10 parts Acetylene glycol EO adduct 0.5 parts (manufactured by Kawaken Fine Chemical Co., Ltd.) Ion-exchanged water 59.5 parts.

(Magenta ink)
(1) Preparation of dispersion First, using benzyl acrylate and methacrylic acid as raw materials, an AB type block polymer having an acid value of 300 and a number average molecular weight of 2500 is prepared by a conventional method, and further neutralized with an aqueous potassium hydroxide solution. Diluted with ion-exchanged water to prepare a homogeneous 50% by weight polymer aqueous solution.

  100 g of the polymer solution, C.I. I. 100 g of Pigment Red 122 and 300 g of ion-exchanged water were mixed and mechanically stirred for 0.5 hour.

  The mixture was then processed using a microfluidizer by passing it through the interaction chamber 5 times under a liquid pressure of about 70 MPa.

  Further, the dispersion obtained above was centrifuged (12,000 rpm, 20 minutes) to remove the non-dispersion containing coarse particles to obtain a magenta dispersion. The obtained magenta dispersion had a pigment concentration of 10% by mass and a dispersant concentration of 5% by mass.

(2) Preparation of ink Ink preparation uses the above-mentioned magenta dispersion, and the following components are added to this to obtain a predetermined concentration. After sufficiently mixing and stirring these components, pressure filtration is performed with a micro filter (manufactured by Fuji Film Co., Ltd.) having a pore size of 2.5 μm to obtain a pigment ink having a pigment concentration of 4 mass% and a dispersant concentration of 2 mass%. Prepared.
Magenta dispersion 40 parts Glycerin 10 parts Diethylene glycol 10 parts Acetylene glycol EO adduct 0.5 parts (manufactured by Kawaken Fine Chemical Co., Ltd.) 39.5 parts of ion-exchanged water.

(Yellow ink)
(1) Preparation of dispersion First, the anionic polymer P-1 was neutralized with an aqueous potassium hydroxide solution and diluted with ion-exchanged water to prepare a homogeneous 10% by mass polymer aqueous solution.

  30 parts of the polymer solution, C.I. I. 10 parts of Pigment Yellow 74 and 60 parts of ion-exchanged water are mixed, charged into a batch type vertical sand mill (manufactured by AIMEX), filled with 150 parts of 0.3 mm diameter zirconia beads, and dispersed for 12 hours while cooling with water. Went.

  Further, the dispersion obtained above was centrifuged to remove non-dispersed material containing coarse particles to obtain a yellow dispersion. The resulting yellow dispersion had a solid content of about 12.5% and a weight average particle size of 120 nm.

(2) Preparation of ink The following components were mixed, sufficiently stirred and dissolved / dispersed, followed by pressure filtration with a microfilter having a pore size of 1.0 μm (manufactured by Fuji Film Co., Ltd.) to prepare an ink.
Pigment dispersion obtained above: 40 parts glycerin: 9 parts ethylene glycol: 6 parts acetylene glycol ethylene oxide adduct (trade name: acetylenol EH): 1 part 1,2-hexanediol: 3 parts polyethylene glycol (molecular weight 1000) : 4 parts Water: 37 parts

(Light magenta ink)
(1) Production of Dispersion A magenta dispersion having a pigment concentration of 10% by mass was produced by the same raw material and production method as described for the magenta ink.

(2) Preparation of ink Ink preparation uses the above-mentioned magenta dispersion, and the following components are added to this to obtain a predetermined concentration. After sufficiently mixing and stirring these components, pressure filtration is performed with a micro filter (manufactured by Fuji Film Co., Ltd.) having a pore size of 2.5 μm to obtain a pigment ink having a pigment concentration of 4 mass% and a dispersant concentration of 2 mass%. Prepared.

A commercially available acrylic silicone copolymer is used as a resin for improving the scratch resistance.
Magenta dispersion 8 parts Acrylic silicone copolymer (trade name: Cymac US-450; manufactured by Toagosei Co., Ltd.): 5 parts Glycerin 10 parts Diethylene glycol 10 parts Acetylene glycol EO adduct 0.5 parts (Kawaken Fine Chemicals Co., Ltd.) (Made) 66.5 parts of ion-exchange water.

(Light cyan ink)
(1) Production of Dispersion A cyan dispersion having a pigment concentration of 10% by mass was produced by the same raw material and production method as described for the cyan ink.

(2) Preparation of ink Ink preparation uses the above-mentioned cyan dispersion liquid, and the following components are added thereto to obtain a predetermined concentration. After sufficiently mixing and stirring these components, pressure filtration is performed with a micro filter (manufactured by Fuji Film Co., Ltd.) having a pore size of 2.5 μm to obtain a pigment ink having a pigment concentration of 2 mass% and a dispersant concentration of 2 mass%. Prepared.

A commercially available acrylic silicone copolymer is used as a resin for improving the scratch resistance.
Cyan dispersion 4 parts Acrylic silicone copolymer (trade name: Cymac US-450; manufactured by Toagosei Co., Ltd.): 5 parts Glycerin 10 parts Diethylene glycol 10 parts Acetylene glycol EO adduct 0.5 parts (Kawaken Fine Chemicals Co., Ltd.) (Made) 70.5 parts of ion exchange water.

  The surfactant is generally used as a penetrating agent for the purpose of improving the penetrability of the ink with respect to the recording medium dedicated for inkjet. As the amount of the surfactant added increases, the property of lowering the surface tension of the ink becomes stronger, and the wettability and permeability of the ink with respect to the recording medium are improved. The type and amount of the surfactant acetylene glycol EO adduct, polymer, and the like have an effect on the surface tension, and in this example, the surface tension is preferably about 28 to 29 dyn / cm for any ink. For the measurement of surface tension, a fully automatic surface tension meter CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) was used. Note that the measuring device is not limited to the above examples as long as the surface tension of the ink can be measured.

  Since all the inks of the present embodiment described above use an anionic color material, the pH of the ink is stable on the alkali side, and the value is 8.5 to 9.5. . In general, the pH of the ink is 7.0 or more and 10. From the viewpoint of preventing the elution of impurities from the member in contact with the ink, the deterioration of the material constituting the member, and the decrease in the solubility of the pigment-dispersed resin in the ink. It is preferably adjusted to 0 or less. The pH was measured using a pH METER model F-52 manufactured by Horiba, Ltd. However, as long as the pH of the ink can be measured, the measuring device is not limited to those exemplified above. In the present embodiment, an image is recorded by 6-pass multi-pass printing using the six-color ink described above.

  FIG. 4 is a schematic diagram for explaining multi-pass printing of 6 passes employed in the present invention. In the case of 6-pass multi-pass printing, the discharge port array 24 is divided into first to sixth blocks corresponding to 208 discharge ports. The recording medium S is conveyed in the sub-scanning direction (y direction) by a distance corresponding to one block during each recording scan. As a result, in the unit area of the recording medium S, an image is formed stepwise by six recording scans by the first to sixth blocks. At this time, in each printing scan, a mask pattern is used for setting which printing scan each pixel included in the unit area is actually printed.

  FIG. 5 is a diagram for explaining a commonly used mask pattern. The mask pattern is composed of six patterns 1 to 6, and the patterns 1 to 6 are associated with each of the first block to the sixth block in the ejection port array 24. In the patterns 1 to 6, each square corresponds to one pixel area that determines whether ink ejection is permitted or not. In the figure, black indicates a print-allowed pixel (1) and white indicates a non-printable pixel (0). Yes. Note that patterns 1 to 6 formed of an 8 pixel × 4 pixel region are patterns serving as a unit of a mask pattern, and each block is repeatedly used in the x direction and the y direction.

  In the figure, in the first block and the sixth block, 6 pixels out of 8 pixels × 4 pixels are set as recording allowable pixels, and the recording rate is 15%. In the second block and the fifth block, 8 pixels are set as recording allowable pixels, and the recording rate is 25%. In the third block and the fourth block, 11 pixels are set as print permitting pixels, and the printing rate is 35%. When all of these are added, the recording rate is 150% for the unit area. In all the pixels included in the unit area, dot recording is allowed by one or two of the six recording scans of the first to sixth blocks.

  In the mask pattern processing shown in step S803 of FIG. 3, an AND operation is performed between the binary data obtained in step S802 and the mask pattern, so that ink is actually ejected in each printing scan. The discharge data is generated. Hereinafter, a problem in the case where 6-pass multi-pass printing is performed bidirectionally using such a mask pattern will be described.

  As shown in FIG. 5, each unit area in the recording medium has a length W corresponding to the width of the recording medium, and the forward recording scan and the backward recording scan are alternately performed to record an image. Is done. Here, for example, when attention is paid to the area A on the left side of the unit area, the ink is applied by the first block at the beginning of the forward scanning, and then the backward scanning of the carriage 1 is completed after approximately one round-trip scanning of the carriage 1 is completed. Ink is applied by the second block at the end of. Then, after ink is applied by the second block, immediately after the scanning direction of the carriage 1 is changed, ink is applied by the third block at the beginning of forward scanning. Further, after the carriage 1 has completed the reciprocal scanning for about one time, ink is applied by the fourth block at the end of the backward scanning, and immediately after the carriage scanning direction is changed, the fifth block again at the beginning of the forward scanning. Ink is applied. Further, after the reciprocating scanning of the carriage 1 is completed, ink is applied by the sixth block at the end of the backward scanning, and the image is completed. As described above, in the region A located on the left side of the unit region, a relatively long time is required between the first scan and the second scan, between the third scan and the fourth scan, and between the fifth scan and the sixth scan. Elapses and other successive scans are performed in a relatively short time.

  On the other hand, when attention is paid to the right area B in the unit area, the ink is applied to the area by the first block at the end of the forward scanning, and then immediately after the carriage scanning direction is changed, the second is applied at the beginning of the backward scanning. Ink is applied by the block. Then, after the ink is applied by the second block, the ink is applied by the third block at the end of the forward scanning after the carriage 1 has completed approximately one reciprocating scanning. Further, after ink is applied by the third block, immediately after the carriage scanning direction is changed, ink is applied by the fourth block at the beginning of the backward scanning. Ink is applied by the fifth block at the end of the forward scanning after the carriage 1 completes the reciprocating scanning for about one time. Further, immediately after the carriage scanning direction is changed, ink is applied by the sixth block at the beginning of the backward scanning, and the image is completed. That is, in the region B located on the right side of the unit region, a relatively long time elapses between the second scan and the third scan, between the fourth scan and the fifth scan, and between the fifth scan and the sixth scan. However, other successive scans are performed in a relatively short time.

  As described above, even in an area where images are recorded by the same six recording scans included in the same unit area, the interval at which ink is actually applied varies depending on the position in the main scanning direction. Such a difference in timing at which the ink is applied may be confirmed as a difference in gloss when the pigment ink as described above is used.

  FIGS. 6A and 6B are schematic diagrams for explaining the reason why the glossiness varies depending on the time difference between two printing scans. Both figures show cross-sectional views when ink is applied onto the recording medium S in two portions. When the two recording scans are executed with a relatively short time difference, when the fixing of the ink applied in the first scan is not yet progressing and is in a fluid state, a new one is obtained by the second scan. Ink is applied. In this case, the ink applied in the second scan is fluidly mixed with the ink applied in the first scan, and ink leveling occurs. As a result, after the two recording scans are completed, a relatively smooth ink layer 25 as shown in FIG. 6A is obtained, and is recognized as an image region having a high glossiness.

  On the other hand, when the two recording scans are executed with a relatively long time difference, the ink applied in the first scan is fixed and the ink is not fluid and new ink is applied by the second scan. The In this case, the ink applied in the second scan is unlikely to mix with the ink applied in the first scan, and ink leveling is unlikely to occur. As a result, the ink mass given by the second scan overlaps the ink layer given by the first scan, resulting in an ink layer 25 having a relatively large unevenness as shown in FIG. Recognized as a low image area. However, even in such a case, if the amount of ink applied earlier is sufficiently smaller than the amount of ink applied later, the ink applied earlier is included in the leveling of the ink applied later. Smooth layer is formed.

  Here, in the case of 6-pass multi-pass printing shown in FIG. 5, a process in which a relatively long time elapses due to the reciprocating scanning of the carriage is represented as “time difference”. In addition, a process in which ink is applied within a relatively short period of time in which leveling is performed, including switching of the traveling direction of the carriage, is referred to as “recording”. In other words, inks recorded in the same “recording” process form the same layer by leveling, but inks recorded in two “recording” processes sandwiching a “time difference” are not leveled and another layer is formed. It can be considered to form. In this case, in area A, ink is applied in the process of “recording” → “time difference” → “recording” → “time difference” → “recording” → “time difference” → “recording”, and 4 in four “recording” processes. An image is formed by the layers. On the other hand, in region B, ink is applied in the process of “recording” → “time difference” → “recording” → “time difference” → “recording”, and an image is formed by three layers by three “recording” processes. That is, even in the same unit region, the ink stacking state is different on the left and right, and this appears as a difference in glossiness. In particular, in the last recording scan, in the region A where ink is applied after a relatively long time, a new ink mass is formed on the leveled fixing layer, so that irregularities are formed on the surface. As a result, the glossiness decreases.

  In addition, in another unit region adjacent to such a unit region in the sub-scanning direction, the scanning direction recorded by each block is reversed, so that the magnitude relationship between the left and right glossiness is also reversed. For this reason, at the left end portion and the right end portion of the recording medium, unit areas with high glossiness and unit areas with low glossiness are alternately arranged in the transport direction and recognized as uneven gloss. Such gloss unevenness tends to be noticeable because the scanning distance of the carriage and the time difference also increase as the width size of the recording medium increases. For the central region C, the first to sixth scans are executed at almost equal intervals in any unit region, and therefore the difference in glossiness between adjacent unit regions is not noticeable.

  In the present embodiment, characteristic recording control is executed to reduce the uneven glossiness as described above. Specifically, for the first block corresponding to the first recording scan and the sixth block corresponding to the last recording scan, the recording rate at the beginning of the recording scan is smaller than the recording rate at the end of the recording scan. A mask pattern is prepared, and the recording rate is changed within the same scan.

  FIG. 7 is a diagram showing a mask pattern used in this embodiment. The difference from the conventional general mask pattern shown in FIG. 5 is that only the first block and the sixth block change the recording rate within the same scan. Here, for explanation, the pattern used at the beginning of the printing scan in the first block is shown as pattern 1S, and the pattern used at the end of the printing scan is shown as pattern 1E. In the sixth block, the pattern used at the beginning of the recording scan is shown as pattern 6S, and the pattern used at the end of the recording scan is shown as pattern 6E. On the other hand, the second to fifth blocks are used without changing the patterns 2 to 5 in the same scan as in FIG.

  When such a mask pattern is used, in the region A on the left side of the figure, images are recorded in this order by the pattern 1S, the pattern 2, the pattern 3, the pattern 4, the pattern 5, and the pattern 6E. . On the other hand, in the region B on the right side of the figure, images are recorded in this order by the pattern 1E, the pattern 2, the pattern 3, the pattern 4, the pattern 5, and the pattern 6S.

  Here, paying attention to the patterns of the first block and the sixth block, the recording rate of the pattern 1S and the pattern 6S used at the beginning of the recording scan is 5%, and the recording rate of the pattern 1E and the pattern 6E used at the end of the recording scan. Is 25%. At this time, as described above, even when the two recording scans are performed with a relatively long time difference, if the amount of ink applied first is sufficiently smaller than the ink applied later, The applied ink tends to be included in the leveling of the subsequently applied ink.

  That is, in the case of the area A of the present embodiment, the ink recorded in the first “recording” process with a recording rate of 5% is included in the same layer by the leveling of the next “recording” process with a recording rate of 25%. Can be considered. Therefore, if these two “recording” processes are shown as one “recording” process, the ink application process in both region A and region B is “recording” → “time difference” → “recording” → “time difference” → “recording”. To be unified. In other words, both the area A and the area B are formed by three layers by three “recording” processes. In particular, in the last recording scan, in the area A to which ink is applied after a relatively long period of time, leveling is promoted by increasing the recording rate, and the glossiness increases. In this way, by using the mask pattern shown in FIG. 7, the glossiness of the regions A and B can be made closer than in the case of FIG. 5, and the uneven gloss can be made inconspicuous.

  In FIG. 7, only the patterns 1S and 6E used in the left area A and the patterns 1E and 6S used in the right area B have been described. However, the area between them greatly deviates from the recording rate of these patterns. It is preferable to use a pattern without any.

  8A to 8C are diagrams illustrating examples of patterns used in the region between the region A and the region B. FIG. Here, for the sake of simplicity, mask patterns used in the first recording scan that is the forward scanning and the sixth recording scan that is the backward scanning are used for the unit region having 48 pixels in the main scanning direction. Show. FIG. 8A shows a case where the pattern is switched at the center in the scanning direction. Specifically, in the first recording scan (first block), the pattern 1S is used from the beginning of the recording scan to the center position, and the pattern 1E is used from the center position to the end of the recording scan. In the sixth recording scan (sixth block), the pattern 6S is used from the beginning of the recording scan to the center position, and the pattern 6E is used from the center position to the end of the recording scan.

  On the other hand, FIG. 8B shows a mask pattern in which the recording rate is gradually changed from the beginning to the end of the recording scan. Specifically, at the beginning of the recording scan, the pattern 1S and the pattern 6S having a recording rate of 5% are used for both the first block and the sixth block, and the recording rate is gradually increased as the recording scan proceeds. At the end of the recording scan, the pattern 1E and the pattern 6E having a recording rate of 25% are used for both the first block and the sixth block.

  On the other hand, FIG. 8C uses the characteristic patterns 1S, 1E, 6S, and 6E of the present embodiment only at the beginning and end of the printing scan, and in the other areas, the same pattern as before, that is, the printing rate is 15%. The case where the pattern which is is shown is shown.

  In the present embodiment, any mask pattern shown in FIGS. 8A to 8C can be adopted. In addition to the above three mask patterns, for example, the unit region may be divided into three equal parts in the main scanning direction, and the three-stage pattern shown in FIG. 8C may be used for each region.

  Such a mask pattern is stored in the ROM 304 in advance, and the MPU 302 reads the mask pattern from the ROM 304 and develops it in the mask buffer 307 for use when performing multipass printing. At this time, the ROM 304 may store a mask pattern having a size corresponding to the scanning width in the main scanning direction. For example, a unit of 8 pixels × 4 pixel regions such as patterns 1S, 1E, 6S, and 6E. A plurality of patterns may be stored. In the latter case, the MPU 302 reads out a plurality of patterns used in multi-pass printing from the ROM 304, arranges them according to the width of the recording medium, and develops them in the mask buffer 307.

  FIG. 9 is a diagram showing an effect when the recording control of the present embodiment is employed. Here, the results of measuring the haze value of the output image in each of the regions A and B, the difference between them, and the result of visual determination of the presence or absence of gloss unevenness, the mask pattern of FIG. 7, the mask pattern of FIG. As an example, the case where the mask pattern of FIG. 10 is used is shown. The mask pattern of FIG. 10 prepared as a comparative example has a high recording rate at the beginning of recording scanning (25%) in the same scan, contrary to the mask pattern of this embodiment shown in FIG. Is low (5%).

  The output image used was a premium glossy paper [thin mouth] (manufactured by Canon Inc.) recorded with the black ink (K) described above at a duty of 150%. Moreover, about the haze value, it measured using micro-haze plus by Gardner according to the method defined in JISK7374.

  As can be seen from FIG. 9, when the mask pattern of this embodiment (FIG. 7) was used, the difference in the haze values between the region A and the region B was as small as 0.7 and no uneven gloss was confirmed. On the other hand, when the conventional mask pattern (FIG. 5) was used, the difference in the haze value between region A and region B was as large as 5.5, and uneven gloss was confirmed. Furthermore, when the mask pattern (FIG. 10) prepared as a comparative example was used, the difference in haze values was even greater than in the case of FIG. 5, and uneven gloss was confirmed.

  When the mask pattern shown in FIG. 10 is used, the left area A is formed by four layers by four “recording” processes, and the right area B is formed by three layers by three “recording” processes. Therefore, the glossiness differs between the left and right even in the same unit region. In addition, in the case of FIG. 10, since the recording rate in the fourth “recording” step is further reduced in the area A, the ink droplets applied in this step roughen the ink layer formed in the third “recording” step. The glossiness is further lowered than in the case of FIG. On the other hand, in the area B, since the recording rate in the third “recording” step is further increased, the glossiness is further higher than in the case of FIG. For this reason, when the mask pattern shown in FIG. 10 is used, the difference in glossiness between the left and right is larger than in the case of FIG.

  As described above, according to the present embodiment, uneven gloss that tends to appear at both ends of an image can be suppressed by using a characteristic mask pattern as shown in FIG.

  In the above description, the recording rates of the pattern 1S and the pattern 6S are set to 5%, and the recording rates of the pattern 1E and the pattern 6E are set to 25%. Of course, such values are not limited in the present embodiment. . The recording rate in each recording scan may be appropriately adjusted according to the type of pigment ink to be used, the ink ejection amount, the total ink application amount, the image density, the image gradation, the type of recording medium, and the like. For example, the recording rate of the pattern 1S and the pattern 6S may be set to 0%, the recording rate of the pattern 1E and the pattern 6E may be set to 30%, or the difference between the recording rates may be reduced. Further, the recording rates of the pattern 1S and the pattern 6S and the recording rates of the pattern 1E and the pattern 6E do not need to be equal to each other. Further, since the degree of uneven glossiness depends on the scanning distance of the carriage 1, that is, the width of the recording medium, the recording rate of the pattern may be adjusted according to the width of the recording medium.

  FIG. 5 shows a mask pattern in which the recording rate is varied only in the first block and the sixth block in the same recording scan. However, a mask pattern in which the recording rate is varied in other blocks may be used.

  FIG. 11 is a diagram showing mask patterns that can be used as a modification of the present embodiment. The difference from the mask pattern shown in FIG. 7 is that the recording rate is changed within the same scan for the second block and the fifth block in addition to the first block and the sixth block. Specifically, in the second block and the fifth block, the recording rate of the pattern 2S and the pattern 5S used at the beginning of the recording scan is 20%, and the recording rate of the pattern 2E and the pattern 5E used at the end of the recording scan is 30%. %.

  However, at this time, for the second block and the fifth block, the recording rate at the beginning of the recording scan is set so that the recording rate at the beginning of the recording scan is 30% and the recording rate at the end of the recording scan is 20%. It may be set higher than the recording rate at the end of. Regardless of the setting, since the ink application process is unified in the “recording” → “time difference” → “recording” → “time difference” → “recording” for both the area A and the area B, The effect of this embodiment that suppresses the left-right difference can be obtained.

  As shown in FIG. 11, by further increasing the number of blocks that change the recording rate within the same scan, the ink lamination state described in FIG. 6 can be more positively unified on the left and right. Further, not only gloss unevenness but also other problems such as color unevenness and connecting stripes can improve the overall image quality.

  In any case, a mask pattern that suppresses the recording rate at the beginning of the recording scan and increases the recording rate at the end of the recording scan in at least the first recording scan and the last recording scan of bidirectional multi-pass recording. If prepared, uneven gloss can be suppressed.

(Second Embodiment)
Also in this embodiment, bidirectional multi-pass printing is performed using the same ink jet recording apparatus 30 and pigment ink as in the first embodiment. However, in this embodiment, it is assumed that 5-pass multi-pass printing is performed instead of 6-pass multi-pass printing. In the case of 5-pass multi-pass printing, the ejection port array 24 is divided into first to fifth blocks, and the recording medium S is moved in the sub-scanning direction by a distance corresponding to one block during each printing scan. It is conveyed in the (y direction). In the unit area of the recording medium S, an image is formed by five recording scans by the first to fifth blocks.

  FIG. 12 is a diagram showing a mask pattern used in this embodiment. As in the first embodiment, the recording rate is changed within the same scanning only for the first recording scan (first block) and the last recording scan (fifth block). However, in the first recording scan (first block) of the present embodiment, unlike the first embodiment, the recording rate (30%) of the pattern 1S at the beginning of the recording scan is the same as that of the pattern 1E at the end of the recording scan. It is larger than the rate (5%). On the other hand, for the last recording scan (fifth block), as in the first embodiment, the recording rate (5%) of the pattern 5S at the beginning of the recording scan is the recording rate (35) of the pattern 5E at the end of the recording scan. %). Such a difference is based on whether a plurality of printing scans in multi-pass printing is an odd number or an even number.

  In the case of even-pass multi-pass printing, the first printing scan and the last printing scan are performed in different directions with respect to the unit area. In the case of odd-pass multi-pass printing, the first printing scan and the last printing scan are performed in the same direction with respect to the unit area. On the other hand, in multi-pass printing, in order to make the sum of the printing rates of all printing scans constant (150%), in the area A where the printing rate of the last printing scan is small, the printing rate of the first printing scan is large, and the last printing In the region B where the scanning recording rate is large, it is necessary to reduce the recording rate of the first recording scan. For this reason, in odd-pass multi-pass printing, if the recording allowance rate at the start of scanning in the last printing scan is set to be smaller than the recording rate at the end of scanning, the recording rate at the start of scanning is set to be lower than the recording rate at the end of scanning. It will be set larger.

  In the present embodiment using the mask pattern shown in FIG. 12, in area A, ink is applied in the process of “recording” → “time difference” → “recording” → “time difference” → “recording”. Ink is applied in the process of “→” time difference ”→“ recording ”→“ time difference ”→“ recording ”. That is, in both the region A and the region B, an image can be formed by three layers by three “recording” processes, and a difference in glossiness can be suppressed. As described above, according to this embodiment, when performing odd-pass multi-pass printing, uneven glossiness can be obtained by changing the printing rate in the same printing scan in the first printing scan and the last printing scan. It is possible to output a uniform image without any problem.

(Third embodiment)
In the present embodiment, in addition to the six-color (CMYKLcLm) ink, a processing liquid for further improving the performance of the image by the pigment ink is prepared. Hereinafter, the components of the treatment liquid used in the present embodiment and the production method will be described.

(1) Preparation of processing liquid The following components were mixed and sufficiently stirred to prepare a processing liquid.
Commercially available acrylic silicone copolymers (trade name: Cymac US-450; manufactured by Toagosei Co., Ltd.): 5 parts glycerin: 5 parts ethylene glycol: 15 parts acetylene glycol ethylene oxide adduct (trade name: acetylenol EH) ): 0.5 part Water: 74.5 parts

  The treatment liquid contains the same resin material as the light cyan ink and light magenta ink used in the first embodiment. However, the components of the treatment liquid shown here are merely examples, and the detailed components of the treatment liquid are not particularly limited as long as the resin material can improve scratch resistance, glossiness, and haze. .

  In the present embodiment, an ejection port array, an ink tank, and a cap for processing liquid are added to the ink jet recording apparatus described in FIGS. 1 (a) and 1 (b). At this time, the discharge port array for the processing liquid is configured by arranging 640 discharge ports at a density of 1200 dpi, and is shifted from the six ink discharge port arrays 24 to the downstream side (+ y direction) in the transport direction. To be placed. In addition, the processing liquid is recorded with a uniform duty in the area where the pigment ink is recorded, regardless of the recording amount of the pigment ink. For this reason, the treatment liquid is always applied to the upper layer of the ink layer formed of the pigment ink.

  FIG. 13 is a cross-sectional view showing a state in which the treatment liquid is applied on the ink layer 25. The thickness of the treatment liquid layer 26 is usually about 100 nm to 500 nm. By providing such a transparent layer with the treatment liquid, it is possible to improve the scratch resistance, glossiness, and haze of the image.

  By the way, the tendency of the glossiness of an image differs depending on the type of liquid contained in the ink or the processing liquid. For example, in an ink that contains a large amount of water-soluble resin relative to the pigment content, or in a treatment liquid that contains a large amount of water-soluble resin without pigment, curing as a layer tends to be slow and easy to level. On the other hand, however, once cured over time, there is a tendency to prevent penetration of the liquid applied thereon. For example, even a transparent layer made of a treatment liquid as shown in FIG. 13 is required to have a smooth surface, that is, a sufficient leveling in order to achieve a sufficient glossiness. Therefore, it can be said that it is effective to use a mask pattern that promotes leveling as shown in FIG. 7 in order to obtain a stable gloss with such ink and processing liquid.

  In addition, in an ink having a large solid content such as a pigment, when it is cured with the passage of time, the ink layer applied thereon tends to be high. Therefore, it is effective to use a mask pattern that promotes leveling as shown in FIG. 7 in order to obtain stable glossiness with such ink.

  Ink with low alkali buffering capacity or low base material content, when cured over time, tends to suppress the re-dissolution of the ink applied thereon and increase the height difference of the ink layers. . Therefore, it is effective to use a mask pattern that promotes leveling as shown in FIG. 7 for such ink.

  Further, with an ink in which the haze value of the formed image is high (about 35% or more), a slight difference in haze value is easily visible in the formed image. Therefore, it is effective to use a mask pattern that promotes leveling as shown in FIG. 7 in order to stabilize the haze value of such ink.

  In addition, even in an image formed with a plurality of types of pigment inks, if the total content of the resins contained in the plurality of types of pigment inks is large, curing as an ink layer is slow and easy to level, but cures over time. Then, there is a tendency to prevent penetration of the ink applied thereon. Therefore, even in such a case, the mask pattern for promoting leveling as shown in FIG. 7 functions effectively.

  On the other hand, in the case of ink that does not have the above remarkable features, in order to obtain the original effect of multi-pass printing in which the discharge frequency is dispersed as evenly as possible in each printing scan, the conventional method shown in FIG. It may be preferable to use a general mask pattern. Therefore, in the present embodiment, different mask patterns can be used for each of the ink type and the treatment liquid.

  In addition, for example, the light cyan ink (Lc), light magenta ink (Lm) containing the acrylic silicone copolymer and the processing liquid use the mask pattern shown in FIG. 7, and the other masks shown in FIG. 5 are used for the other inks. Use patterns. At this time, the recording rates of the patterns 1S, 5S, 1E, and 5E may be different from each other for the light cyan ink, the light magenta ink, and the processing liquid. For some inks, the recording rate may be changed within a larger number of recording scans as shown in FIG. Furthermore, the mask pattern corresponding to each color may be appropriately changed according to the recording mode, the type and size of the recording medium, the combination of inks to be used, and the like.

  In any case, if an appropriate mask pattern is prepared for each ink and processing solution according to the state of uneven gloss, uneven color, and stripes, smooth images by multi-pass printing can be achieved and uneven gloss can be achieved. High quality images can be output.

(Other embodiments)
In the embodiment described above, the mask pattern is used as means for changing the recording rate tolerance in the same recording scan in at least the first recording scan and the last recording scan in bidirectional multi-pass recording. However, the present invention is not limited to the form using the mask pattern. For example, ejection data for each printing scan is generated by performing a predetermined calculation using the printing rate set for each region in the main scanning direction on the binary data generated in step S802 in FIG. May be. Further, the multi-value data generated in step S801 may be distributed to a plurality of recording scans according to the recording rate set for each region in the main scanning direction, and then binarization processing may be performed.

  In the above-described embodiment, the glossiness of the entire image area is basically increased. However, the present invention is not limited to this. An object of the present invention is to reduce uneven gloss due to variations in glossiness. In multi-pass printing, if the difference in glossiness at both ends of the printing medium can be reduced by changing the printing rate at least between the first and last printing scans, what value is the glossiness itself? It doesn't matter.

  In the above description, an ink jet recording apparatus using six color pigment inks has been described as an example. However, the type of ink to be used is not limited to this. The ink to be used may be, for example, four colors of cyan, magenta, yellow, and black, or may be a monochrome recording apparatus using only black. In addition, inks such as red, green, blue, and gray may be further added.

  Of course, the components and manufacturing methods of these inks and treatment liquids are not limited to those described above. The pigment inks shown above are mainly manufactured with components that place importance on scratch resistance, and the processing liquids are mainly used for components with an emphasis on scratch resistance, gloss, and haze, but these are bronze, water resistant, and alkali resistant. In addition, the components may be adjusted so as to give more importance to weather resistance and the like. The ink used is not limited to pigment ink. Even in the case of dye ink, the gloss unevenness as described above may be confirmed in the ink that tends to remain on the surface of the recording medium, and the above embodiment functions effectively.

  In the above description, the inkjet recording apparatus having a configuration in which a plurality of ejection port arrays are arranged in parallel in the main scanning direction has been described as an example. However, the layout of the ejection port arrays is not limited to the above embodiment. The plurality of ejection port arrays may have different lengths in the sub-scanning direction, or may be arranged at positions shifted from each other in the sub-scanning direction.

  In the above description, the image data received from the host computer is subjected to predetermined image processing, and then the multi-pass recording is performed using the mask pattern stored in the ROM 304. However, the present invention is not limited to this form. The process shown in FIG. 3 may be executed by being shared by both the host computer and the ink jet recording apparatus. Specifically, for example, the process up to the mask pattern processing in step S803 may be executed by the host computer, and the printing apparatus may receive the ejection data associated with each printing scan and execute the printing scan according to this. . In this case, the entire system including the host computer and the ink jet recording apparatus is the ink jet recording system of the present invention.

  The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

22 Recording head
30 Inkjet recording device 302 MPU
303 ASIC
S Recording medium

Claims (16)

In an ink jet recording apparatus that records an image by a plurality of recording scans of the recording head in a unit area of the recording medium by alternately scanning the recording head that ejects ink in the forward direction and the backward direction with respect to the recording medium.
Generating means for generating ejection data corresponding to each of the plurality of printing scans based on image data corresponding to the unit area;
A recording unit that causes the recording head to execute the plurality of recording scans according to the ejection data for the unit area;
The generating means includes the plurality of recording scans for the unit area.
In the first recording scan and the last recording scan, the recording rate is changed within the same recording scan, and
An ink jet recording apparatus that generates ejection data corresponding to each of the plurality of recording scans so that the recording rate at the beginning of the recording scan is smaller than the recording rate at the end of the recording scan in the last recording scan . The plurality of recording scans is an even number of recording scans,
The generation unit generates ejection data corresponding to each of the plurality of printing scans so that a printing rate at the beginning of the printing scan is smaller than a printing rate at the end of the printing scan for the unit area. The inkjet recording apparatus according to claim 1. The plurality of recording scans is an odd number of recording scans,
The generation unit generates ejection data corresponding to each of the plurality of printing scans so that a printing rate at the beginning of the printing scan is larger than a printing rate at the end of the printing scan for the unit area. The inkjet recording apparatus according to claim 1.   The generating unit can cope with each of the plurality of printing scans by using a mask pattern for determining whether ink discharge is permitted or not allowed in the plurality of printing scans for each of the plurality of pixels constituting the unit region. The inkjet recording apparatus according to claim 1, wherein ejection data to be generated is generated.   5. The apparatus according to claim 1, wherein the generation unit varies the recording rate at the beginning and the recording rate at the end according to at least one of a type or a width of the recording medium. Inkjet recording device. The recording head ejects a plurality of types of ink and a treatment liquid for improving the performance of an image recorded by the ink,
6. The apparatus according to claim 1, wherein the generation unit individually generates ejection data corresponding to each of the plurality of printing scans for the plurality of types of ink and the processing liquid. Inkjet recording apparatus.   The ink jet recording apparatus according to any one of claims 1 to 6, wherein the ink is a pigment ink. In an inkjet recording method for recording an image by a plurality of recording scans of the recording head in a unit area of the recording medium by alternately scanning the recording head for ejecting ink in the forward direction and the backward direction with respect to the recording medium.
A generating step of generating ejection data corresponding to each of the plurality of recording scans based on image data corresponding to the unit region;
A recording step of causing the recording head to execute the plurality of recording scans according to the ejection data with respect to the unit area;
The generating step includes changing the recording rate within the same recording scan in the first recording scan and the last recording scan among the plurality of recording scans for the unit area, and in the last recording scan. An ink jet recording method comprising: generating ejection data corresponding to each of the plurality of recording scans so that a recording rate at the beginning of the recording scan is smaller than an end recording rate. The plurality of recording scans is an even number of recording scans,
The generating step generates ejection data corresponding to each of the plurality of recording scans so that the first recording scan of the unit area has a recording rate at the beginning of the recording scan smaller than an end recording rate. The inkjet recording method according to claim 8. The plurality of recording scans is an odd number of recording scans,
The generating step generates ejection data corresponding to each of the plurality of printing scans so that a printing rate at the beginning of the printing scan is larger than a printing rate at the end of the printing scan for the unit area. The inkjet recording method according to claim 8.   The generating step corresponds to each of the plurality of print scans by using a mask pattern that determines whether ink discharge is permitted or not permitted in the plurality of print scans for each of the plurality of pixels constituting the unit region. The inkjet recording method according to claim 8, wherein ejection data to be generated is generated.   12. The generation process according to claim 8, wherein the generation step makes the start recording rate and the end recording rate different according to at least one of a type or a width of the recording medium. 13. Inkjet recording method. The recording head ejects a plurality of types of ink and a treatment liquid for improving the performance of an image recorded by the ink,
9. The generating step according to claim 8, wherein the plurality of types of ink and the processing liquid are individually generated so that ejection data corresponding to each of the plurality of recording scans is different from each other. 13. The inkjet recording method according to any one of items 12.   14. The ink jet recording method according to claim 8, wherein the ink is a pigment ink.   A program for causing one or more processors to execute the ink jet recording method according to claim 1. An ink jet recording system for recording an image by a plurality of recording scans of the recording head in a unit area of the recording medium by alternately scanning the recording head for ejecting ink in the forward direction and the backward direction with respect to the recording medium In
Generating means for generating ejection data corresponding to each of the plurality of printing scans based on image data corresponding to the unit area;
Means for transmitting the ejection data in order to cause the recording head to perform the plurality of recording scans in accordance with the ejection data for the unit area;
The generating means changes the recording rate within the same recording scan in the first recording scan and the last recording scan among the plurality of recording scans for the unit area, and in the last recording scan, An inkjet recording system, wherein ejection data corresponding to each of the plurality of recording scans is generated so that a recording rate at the beginning of the recording scan is smaller than an end recording rate.