Inkjet recording system and inkjet recording method

Abstract

In the present invention, a computer creates pieces of ink-dot data for each pass operation for forming a unit image on media. When doing so, the computer sets the position in the sub-scanning direction of each of a plurality of boundary end portion dots so as to be a position corresponding to wave shapes of a plurality of patterns with different phases, the boundary end portion dots being side by side in the main scanning direction and defining the boundary of the sub-scanning direction of unit images adjacent to each other in the sub-scanning direction on the media, and being from among boundary region formation dots for forming a boundary region between unit images adjacent to each other among a plurality of ink dots included in each piece of ink-dot data for each pass operation.

Description

Technical Field

[0001] The present invention relates to an inkjet recording system and an inkjet recording method.

Background Art

[0002] An inkjet printer that performs printing processing on a recording material by a serial printing method is known. In an inkjet printer using a serial printing method, a pass operation of forming a strip-shaped unit image extending in the main scanning direction on the recording material by discharging ink from an ink head while moving the ink head in the main scanning direction, and a conveyance operation of conveying the recording material in a sub-scanning direction orthogonal to the main scanning direction are alternately and repeatedly performed.

[0003] When forming an image by a serial printing method, streak-like density unevenness extending in the main scanning direction may occur in a boundary region between unit images for each pass operation adjacent to each other in the sub-scanning direction on the recording material, and the quality of the image may deteriorate. A technique for solving such a problem is disclosed in, for example, Patent Document 1. In the technique disclosed in Patent Document 1, as data of an ink dot pattern for forming a unit image, pattern data is created in which end dots in the sub-scanning direction defining the boundary between unit images form uneven portions.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

[0005] An inkjet recording system according to one aspect of the present invention includes an ink head that is movably provided in a main scanning direction and can eject ink onto a recording material, a conveyance unit that can convey the recording material in a sub-scanning direction orthogonal to the main scanning direction, a pass operation that forms a plurality of ink dots on the recording material by ejecting the ink from the ink head while moving the ink head in the main scanning direction, and a conveyance operation of the recording material in the sub-scanning direction by the conveyance unit. By repeatedly performing these operations, a control unit performs an image forming process of forming a plurality of unit images composed of a plurality of the ink dots corresponding to at least one pass operation in the sub-scanning direction on the recording material, and a dot data creation unit performs an ink data creation process of creating ink dot data indicating data of patterns of a plurality of the ink dots for forming each of the plurality of unit images on the recording material for each pass operation. In the image forming process, the control unit performs the pass operation and the conveyance operation so that a boundary region in which a part of the unit images adjacent to each other in the sub-scanning direction overlaps in the sub-scanning direction and extends in the main scanning direction is formed on the recording material. In the ink data creation process, the dot data creation unit sets positions of a plurality of boundary end dots arranged in the main scanning direction, which define a boundary in the sub-scanning direction between the unit images adjacent to each other in the sub-scanning direction on the recording material, among the boundary region forming dots for forming the boundary region, in the plurality of ink dots included in each ink dot data for each pass operation, to positions corresponding to a plurality of pattern waveforms having different phases and having a wavelength corresponding to the main scanning direction and an amplitude corresponding to the sub-scanning direction. According to such an inkjet recording system according to one aspect of the present invention, it is possible to suppress a decrease in the quality of an image formed on a recording material.

[0006] An inkjet recording method according to another aspect of the present invention is a method of recording an image on a recording material using an ink head movable in a main scanning direction. This inkjet recording method includes a pass operation of forming a plurality of ink dots on the recording material by discharging ink from the ink head while moving the ink head in the main scanning direction, and a conveyance operation of conveying the recording material in a sub-scanning direction orthogonal to the main scanning direction. By repeatedly performing these operations, an image forming step of forming a plurality of unit images composed of a plurality of the ink dots corresponding to at least one pass operation in the sub-scanning direction on the recording material, and an ink data creation step of creating ink dot data indicating data of patterns of a plurality of the ink dots for forming each of the plurality of unit images on the recording material for each pass operation are included. In the image forming step, the pass operation and the conveyance operation are performed so that a boundary region in which a part of the unit images adjacent to each other in the sub-scanning direction overlaps in the sub-scanning direction and extends in the main scanning direction is formed on the recording material. In the ink data creation step, among a plurality of the ink dots included in each of the ink dot data for each pass operation, positions in the sub-scanning direction of a plurality of boundary end dots arranged in the main scanning direction, which define the boundary in the sub-scanning direction between the unit images adjacent to each other in the sub-scanning direction on the recording material, are set to positions corresponding to a plurality of pattern waveforms having different phases and having a wavelength corresponding to the main scanning direction and an amplitude corresponding to the sub-scanning direction. According to such an inkjet recording method according to another aspect of the present invention, it is possible to suppress a decrease in the quality of an image formed on a recording material.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

[0008] In the technique disclosed in Patent Document 1 described above, since the end dots in the sub-scanning direction are regulated to be arranged in a straight line along the main scanning direction, it is considered that the occurrence of linear density unevenness along the main scanning direction can be suppressed. However, since the end dots in the sub-scanning direction are arranged along a single waveform having uneven portions, there is a possibility that streak-like density unevenness along the single waveform may occur in the boundary region between unit images.

[0009] Therefore, there is a need for an inkjet recording system and an inkjet recording method capable of suppressing a decrease in the quality of an image formed on a recording material.

[0010] Hereinafter, an inkjet recording system according to an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, as a specific example of the inkjet recording system, a system including an inkjet printer having an ink head capable of discharging ink for image formation onto a wide and long recording material is exemplified. The inkjet printer is suitable for digital textile printing in which images such as characters and patterns are printed (recorded) by an inkjet method on a recording material that is a cloth member made of a cloth fabric such as a woven or knitted fabric. Of course, the inkjet printer applied to the inkjet recording system according to the present invention can also be used for applications in which various images are printed on a recording material such as a paper sheet or a resin sheet.

[0011] As shown in FIG. 1, an inkjet recording system 1 includes an inkjet printer 2 and a computer 6 that is communicably connected to the inkjet printer 2 for data communication. FIG. 1 shows a schematic configuration of the inkjet printer 2 in a state viewed from above in a plan view. In the inkjet recording system 1, the computer 6 functions as a dot data creation unit that creates ink dot data DID and processing liquid dot data DRD based on image data DG of an image to be printed on a medium W that is a recording material. The inkjet printer 2 prints an image on the medium W by an inkjet method based on the ink dot data DID and the processing liquid dot data DRD created by the computer 6. Note that in the inkjet recording system 1, the computer 6 may be incorporated in the inkjet printer 2. That is, the inkjet printer 2 may have a function as a dot data creation unit in addition to the function of printing an image on the medium W by an inkjet method.

[0012] The inkjet printer 2 is a printer that prints an image on a wide and long medium W by an inkjet method, and includes an inkjet head 20 including an ink head 3 and a processing liquid head 4, a conveyance unit 21 capable of conveying the medium W in a conveyance direction F, and a carriage 22 on which the inkjet head 20 is mounted.

[0013] The inkjet printer 2 is a so-called serial printer that performs printing processing on the medium W in a serial printing method. In the serial printing method inkjet printer 2, as shown in FIG. 2, while reciprocating the carriage 22 in the main scanning direction H1, ink is ejected from the ink head 3 to form a plurality of ink dots ID on the medium W. A pass operation and a conveyance operation of conveying the medium W in the conveyance direction F parallel to the sub-scanning direction H2 orthogonal to the main scanning direction H1 on a horizontal plane are repeatedly performed. As a result, a plurality of strip-shaped unit images GA extending in the main scanning direction H1, each consisting of a plurality of ink dots ID corresponding to at least one pass operation, are formed on the medium W in the sub-scanning direction H2. In the pass operation, the processing liquid may be ejected from the processing liquid head 4. The conveyance operation is performed by the conveyance unit 21. Also, the pass operation and the conveyance operation may be repeatedly performed alternately or may be repeatedly performed one by one in order.

[0014] The conveyance unit 21 includes a feed roller 211 that feeds out the medium W before printing and a take-up roller 212 that takes up the medium W after printing. The feed roller 211 is disposed at the upstream end in the conveyance direction F and is a shaft that supports a roll that is a winding body of the medium W before printing. The take-up roller 212 is disposed at the downstream end in the conveyance direction F and is a shaft that supports a roll that is a winding body of the medium W after printing. A drive source such as a motor that rotationally drives the take-up roller 212 about its axis and executes the take-up operation of the medium W is attached to the take-up roller 212. The conveyance unit 21 conveys the medium W in the conveyance direction F by the feed roller 211 being driven to rotate passively in response to the rotational drive of the take-up roller 212.

[0015] The carriage 22 mounts the ink head 3 and the processing liquid head 4 included in the inkjet head 20, and is capable of reciprocating in the main scanning direction H1 orthogonal to the conveyance direction F. The carriage 22 is fixed to a timing belt 24 that is assembled to be capable of orbiting relative to a flat carriage guide 23 extending in the main scanning direction H1. The timing belt 24 is an endless belt and is driven to orbit in the main scanning direction H1 in a state of being assembled to the carriage guide 23. The carriage 22 reciprocates in the main scanning direction H1 along the carriage guide 23 as the timing belt 24 orbits in the main scanning direction H1.

[0016] Each of the ink head 3 and the processing liquid head 4 mounted on the carriage 22 is capable of relative movement with respect to the media W in the main scanning direction H1 and the sub-scanning direction H2 as the media W is conveyed in the conveyance direction F by the conveyance unit 21 and the carriage 22 reciprocates in the main scanning direction H1.

[0017] In the present embodiment, the ink head 3 includes a plurality of individual heads 31 capable of discharging each of a plurality of colors of ink, and these plurality of individual heads 31 are mounted on the carriage 22. Each of the plurality of individual heads 31 includes a number of nozzles that discharge ink droplets by a discharge method such as a piezo method using a piezo element or a thermal method using a heating element, an ink flow path that guides ink to the nozzles, and a wiring board for controlling the ink discharge operation. As the ink, for example, aqueous pigment ink containing an aqueous solvent, a pigment, and a binder resin can be used. The plurality of individual heads 31 are mounted on the carriage 22 so as to be arranged in two rows in the main scanning direction H1. Each of the individual heads 31 for each color has two heads. The two individual heads 31 that discharge the same color of ink are mounted on the carriage 22 so as to be arranged at positions shifted from each other in the main scanning direction H1 and the sub-scanning direction H2. As another embodiment, a configuration in which one ink head 3 is mounted on the carriage 22 can be mentioned.

[0018] In this embodiment, as the processing liquid head 4, a pretreatment liquid head 41 and a post-treatment liquid head 42 are mounted on the carriage 22 respectively. The pretreatment liquid head 41 and the post-treatment liquid head 42 are mounted on the carriage 22 so as to be arranged at positions different from those of the ink head 3 in the conveyance direction F parallel to the sub-scanning direction H2. The pretreatment liquid head 41 is mounted on the carriage 22 so as to be arranged on the upstream side of the ink head 3 in the conveyance direction F. In FIG. 1, an example is shown in which one pretreatment liquid head 41 is arranged near one end portion in the main scanning direction H1 of the array of a plurality of individual heads 31 in the ink head 3. The post-treatment liquid head 42 is mounted on the carriage 22 so as to be arranged on the downstream side of the ink head 3 in the conveyance direction F. In FIG. 1, an example is shown in which one post-treatment liquid head 42 is arranged near the other end portion in the main scanning direction H1 of the array of a plurality of individual heads 31 in the ink head 3. As another embodiment, a configuration in which either one of the pretreatment liquid head 41 and the post-treatment liquid head 42 is mounted on the carriage 22 as the processing liquid head 4 can be cited.

[0019] The pretreatment liquid head 41 includes a number of nozzles that discharge pretreatment liquid droplets by a discharge method such as a piezo method using a piezo element, a thermal method using a heating element, etc., a pretreatment liquid flow path that guides the pretreatment liquid to the nozzles, and a wiring board for controlling the discharge operation of the pretreatment liquid. The pretreatment liquid head 41 discharges the pretreatment liquid at a position on the medium W before the ink is discharged by the ink head 3. The pretreatment liquid is a processing liquid that adheres to the medium W before the ink. The pretreatment liquid is a processing liquid that contacts the ink in a state of not being dried on the medium W, and is a non-color-developing processing liquid that does not develop color even when it adheres to the medium W. The pretreatment liquid has a function of preventing the occurrence of bleeding of the ink on the medium W. As such a pretreatment liquid, a processing liquid in which a binder resin is blended in a solvent, or a processing liquid in which a cation resin that is positively charged is blended in a solvent can be used.

[0020] The post-treatment liquid head 42 includes a number of nozzles that discharge post-treatment liquid droplets by a discharge method such as a piezo method using a piezo element, a thermal method using a heating element, etc., a post-treatment liquid flow path that guides the post-treatment liquid to the nozzles, and a wiring board for controlling the discharge operation of the post-treatment liquid. The post-treatment liquid head 42 discharges the post-treatment liquid at a position on the medium W after the ink has been discharged by the ink head 3. The post-treatment liquid is a treatment liquid that adheres to the medium W after the ink. The post-treatment liquid is a treatment liquid that contacts the ink in a state where it has not dried on the medium W, and is a non-color-developing treatment liquid that does not develop color even when it adheres to the medium W. The post-treatment liquid has a function of enhancing the fixing property of the ink on the medium W. As such a post-treatment liquid, a silicone-based treatment liquid or the like can be used. Note that the pre-treatment liquid and the post-treatment liquid are different treatment liquids. Specifically, the components contained in the pre-treatment liquid and the post-treatment liquid are different.

[0021] Here, the non-color-developing treatment liquid refers to a liquid that is not recognized by the human eye as having developed color when printed alone on the medium W. The color here includes those with a chroma of 0 (zero) such as black, white, and gray. The non-color-developing treatment liquid is basically a colorless and transparent liquid, but it is not completely colorless and transparent, and may appear slightly white or the like. Such a color is so faint that when printed alone on the medium W, a person cannot recognize it as having developed color with the naked eye. Note that depending on the type of treatment liquid, when printed alone on the medium W, there may be changes such as gloss on the medium W, but such a state is not color development.

[0022] As shown in FIG. 1, the inkjet printer 2 further includes a printer control unit 5. The printer control unit 5 is a control unit that controls the pass operation by the inkjet head 20 including the ink head 3 and the processing liquid head 4 mounted on the carriage 22 and the conveyance operation of the medium W by the conveyance unit 21. Based on the data created by the computer 6 described later, the printer control unit 5 moves the carriage 22 in the main scanning direction H1 while discharging ink from the ink head 3 and discharging the processing liquid from the processing liquid head 4, and performs an image forming process in which the conveyance operation of the medium W in the conveyance direction F parallel to the sub-scanning direction H2 by the conveyance unit 21 is repeatedly performed. As a result, as shown in FIG. 2, the printer control unit 5 forms a plurality of unit images GA composed of a plurality of ink dots ID corresponding to at least one pass operation on the medium W in the sub-scanning direction H2. In this image forming process, the printer control unit 5 performs the pass operation and the conveyance operation so that a boundary region BA in which a part of the unit images GA adjacent to each other in the sub-scanning direction H2 overlaps in the sub-scanning direction H2 and extends in the main scanning direction H1 is formed on the medium W. The boundary region BA between the unit images GA adjacent to each other in the sub-scanning direction H2 is a region in which the boundary region forming dots IDS, which are the ink dots ID for forming the boundary region BA among the ink dots ID for forming each unit image GA, are mixed along the main scanning direction H1. By forming such a boundary region BA on the medium W, the occurrence of streaks and the like due to the gap between the unit images GA adjacent to each other in the sub-scanning direction H2 is suppressed.

[0023] The printer control unit 5 sets the conveyance length of the medium W for each pass operation in the conveyance operation by the conveyance unit 21 to a length corresponding to the value obtained by dividing the difference between the effective pixel width of the ink head 3 and the boundary region width of the boundary region BA by the number of pass operations for forming the unit image GA. The effective pixel width of the ink head 3 is represented by the number of dots corresponding to the number of nozzles arranged in the sub-scanning direction H2 among the plurality of nozzles provided in the ink head 3. The boundary region width of the boundary region BA indicates the width of the boundary region BA in the sub-scanning direction H2 and is represented by the number of dots of the boundary region forming dots IDS arranged in the sub-scanning direction H2 within the boundary region BA.

[0024] For example, when forming the unit image GA in one pass operation, the printer control unit 5 sets the conveyance length of the medium W for each pass operation in the conveyance operation by the conveyance unit 21 to a length corresponding to the value obtained by dividing the difference between the effective pixel width of the ink head 3 and the boundary region width of the boundary region BA by "1", which is the number of pass operations for forming the unit image GA. In this case, for a plurality of unit images GA that are continuous in the sub-scanning direction H2 on the medium W, the combination of pass operations for forming the boundary region BA between adjacent unit images GA is the combination of the first pass operation and the second pass operation, the second pass operation and the third pass operation, and the following similar combinations of pass operations.

[0025] When forming the unit image GA in two pass operations, the printer control unit 5 sets the conveyance length of the medium W for each pass operation in the conveyance operation by the conveyance unit 21 to a length corresponding to the value obtained by dividing the difference between the effective pixel width of the ink head 3 and the boundary region width of the boundary region BA by "2", which is the number of pass operations for forming the unit image GA. In this case, for a plurality of unit images GA that are continuous in the sub-scanning direction H2 on the medium W, the combination of pass operations for forming the boundary region BA between adjacent unit images GA is the combination of the first pass operation and the third pass operation, the second pass operation and the fourth pass operation, and the following similar combinations of pass operations.

[0026] When forming the unit image GA in four pass operations, the printer control unit 5 sets the conveyance length of the medium W for each pass operation in the conveyance operation by the conveyance unit 21 to a length corresponding to the value obtained by dividing the difference between the effective pixel width of the ink head 3 and the boundary region width of the boundary region BA by "4", which is the number of pass operations for forming the unit image GA. In this case, for a plurality of unit images GA that are continuous in the sub-scanning direction H2 on the medium W, the combination of pass operations for forming the boundary region BA between adjacent unit images GA is the combination of the first pass operation and the fifth pass operation, the second pass operation and the sixth pass operation, the third pass operation and the seventh pass operation, the fourth pass operation and the eighth pass operation, and the following similar combinations of pass operations.

[0027] As described above, the combination of pass operations for forming the boundary region BA between adjacent unit images GA in the sub-scanning direction H2 on the medium W is uniquely determined according to the number of pass operations for forming the unit image GA.

[0028] The computer 6 is a personal computer having a CPU (Central Processing Unit), a storage area such as an HDD (Hard Disk Drive) or a flash memory for storing a processing program, a RAM (Random Access Memory) used as a working area of the CPU, and the like. The computer 6 performs an ink data creation process for creating ink dot data DID and a processing liquid data creation process for creating processing liquid dot data DRD including pre-processing liquid dot data DRD1 and post-processing liquid dot data DRD2 by executing the processing program stored in the HDD or the flash memory, and functions as a dot data creation unit.

[0029] The computer 6 performs an ink data creation process for creating ink dot data DID as data used for controlling ink ejection from the ink head 3 for each pass operation by the printer control unit 5, and a processing liquid data creation process for creating processing liquid dot data DRD as data used for controlling processing liquid ejection from the processing liquid head 4 for each pass operation by the printer control unit 5.

[0030] In the inkjet recording system 1 according to the present embodiment, the printer control unit 5 and the computer 6 execute the processing of each step of the inkjet recording method. The processing of each step of the inkjet recording method executed by the printer control unit 5 and the computer 6 will be described in detail with reference to FIGS. 2 to 4.

[0031] When forming an image on the medium W in the serial printing method shown in FIG. 2 based on the control of the printer control unit 5, streak-like density unevenness extending in the main scanning direction H1 may occur in the boundary region BA between adjacent unit images GA on the medium W in the sub-scanning direction H2, and the quality of the image may deteriorate. In the inkjet recording system 1 according to the present embodiment, the computer 6 creates ink dot data DID such that the occurrence of streak-like density unevenness can be suppressed within the boundary region BA between the unit images GA.

[0032] Specifically, the computer 6 acquires image data DG of the image to be printed on the medium W (image data acquisition step s1). When the image data DG is acquired, the computer 6 performs ink data creation processing for creating ink dot data DID indicating data of patterns of a plurality of ink dots ID for forming each of the plurality of unit images GA on the medium W in accordance with the ejection of ink by the ink head 3, for each one-pass operation, based on the image data DG (ink data creation step s2). The computer 6 converts the image data DG into halftone image data printable by the inkjet printer 2 on the medium W by performing halftone processing such as dither processing on the image data DG. Thereby, the computer 6 creates ink dot data DID having a resolution printable by the inkjet printer 2.

[0033] When creating ink dot data DID for each pass operation, as shown in FIG. 4, the computer 6 sets the positions in the sub-scanning direction H2 of each of a plurality of boundary end dots IDS1 arranged in the main scanning direction H1 among the boundary region forming dots IDS for forming a boundary region BA between adjacent unit images GA in the sub-scanning direction H2 in a plurality of ink dot IDs included in each ink dot data DID for each pass operation to positions corresponding to a plurality of pattern waveforms SW1, SW2, SW3, SW4 having different phases. A plurality of boundary end dots IDS1 arranged in the main scanning direction H1 among the boundary region forming dots IDS for forming the boundary region BA are dots that define a boundary B in the sub-scanning direction H2 between adjacent unit images GA on the medium W.

[0034] In FIG. 4, for a plurality of ink dot IDs included in each ink dot data DID for each pass operation, boundary region forming dots IDS for forming a boundary region BA between unit images GA adjacent to each other in the sub-scanning direction H2 are shown. Specifically, in FIG. 4, boundary region forming dots IDS for forming a boundary region BA between a first unit image GA and a second unit image GA adjacent to the upstream side in the conveyance direction F with respect to the first unit image GA are shown. The boundary region BA is a region where the boundary region forming dots IDS corresponding to the first unit image GA and the boundary region forming dots IDS corresponding to the second unit image GA are mixed along the main scanning direction H1. Also, as described above, the combination of pass operations for forming the boundary region BA between the first unit image GA and the second unit image GA is uniquely determined according to the number of pass operations for forming the unit image GA. The boundary region forming dots IDS of the first unit image GA are shown as dots hatched with a plurality of slashes, and the boundary region forming dots IDS of the second unit image GA are shown as dots hatched with a plurality of dots. Also, among a plurality of boundary end dots IDS1 arranged in the main scanning direction H1 that define the boundary B in the sub-scanning direction H2 between the first unit image GA and the second unit image GA in the boundary region forming dots IDS of the first unit image GA, the boundary end dots IDS1 located within the boundary region BA are shown as dots hatched with a plurality of slashes and surrounded by a thick solid line frame, and the boundary end dots IDS1 located outside the boundary region BA are shown as dots hatched with a plurality of slashes and surrounded by a thick broken line frame. Similarly, among a plurality of boundary end dots IDS1 arranged in the main scanning direction H1 that define the boundary B in the sub-scanning direction H2 between the first unit image GA and the second unit image GA in the boundary region forming dots IDS of the second unit image GA, the boundary end dots IDS1 located within the boundary region BA are shown as dots hatched with a plurality of dots and surrounded by a thick solid line frame, and the boundary end dots IDS1 located outside the boundary region BA are shown as dots hatched with a plurality of dots and surrounded by a thick broken line frame.

[0035] On the medium W, the boundary B in the sub-scanning direction H2 between the first unit image GA and the second unit image GA adjacent to each other in the sub-scanning direction H2 is defined by a boundary end dot IDS1 located at the most upstream in the conveyance direction F at each position in the main scanning direction H1 in the boundary region forming dots IDS corresponding to the first unit image GA, and a boundary end dot IDS1 located at the most downstream in the conveyance direction F at each position in the main scanning direction H1 in the boundary region forming dots IDS corresponding to the second unit image GA.

[0036] The position of each of the plurality of boundary end dots IDS1 arranged in the main scanning direction H1 in the main scanning direction H1 is defined by a main scanning coordinate J indicating coordinates on a coordinate axis parallel to the main scanning direction H1. In the example of FIG. 4, a main scanning coordinate J consisting of a total of 32 coordinate groups of "0, 1, 2, ···, 29, 30, 31" is shown. Similarly, the position of each of the plurality of boundary end dots IDS1 in the sub-scanning direction H2 is defined by a sub-scanning coordinate I indicating coordinates on a coordinate axis parallel to the sub-scanning direction H2. In the example of FIG. 4, within the range of a boundary region width BAW indicating the width in the sub-scanning direction H2 of the boundary region BA between the unit images GA on the medium W, a sub-scanning coordinate I consisting of a total of 10 coordinate groups of "0, 1, 2, ···, 7, 8, 9" is shown.

[0037] When the computer 6 sets the positions in the sub-scanning direction H2 of each of a plurality of boundary end dots IDS1 arranged in the main scanning direction H1, the plurality of pattern waveforms SW1, SW2, SW3, SW4 with different phases are waveforms represented by a pattern of waves that have a wavelength λ corresponding to the main scanning direction H1 and an amplitude A corresponding to the sub-scanning direction H2 and change periodically. Examples of the waves showing the waveforms of the plurality of pattern waveforms SW1, SW2, SW3, SW4 include, for example, sine waves, rectangular waves, triangular waves, and sawtooth waves. In each of the plurality of pattern waveforms SW1, SW2, SW3, SW4, the wave showing the waveform may be a mixture of a plurality of waves or may be the same wave. Also, the number of the plurality of pattern waveforms SW1, SW2, SW3, SW4 is not particularly limited as long as it is "2" or more. In the example of FIG. 4, the computer 6, in a plurality of ink dots ID included in each ink dot data DID for each pass operation, among the boundary region forming dots IDS for forming the boundary region BA, sets the positions in the sub-scanning direction H2 of each of the plurality of boundary end dots IDS1 arranged in the main scanning direction H1 to positions corresponding to four pattern waveforms SW1, SW2, SW3, SW4 with different phases α represented by the sine wave of the following formula (1).

[0038] [Number]

[0039] In formula (1) regarding the sine wave showing the waves of the plurality of pattern waveforms SW1, SW2, SW3, SW4, "A" indicates the amplitude, "ω" indicates the angular frequency, and "α" indicates the phase.

[0040] The wavelengths λ of the plurality of pattern waveforms SW1, SW2, SW3, SW4 are set to values corresponding to, for example, the moving distance MD along the main scanning direction H1 per unit time of the carriage 22. The moving distance MD per unit time of the carriage 22 is represented by the number of dots of the boundary region forming dots IDS arranged in the main scanning direction H1. In the example of FIG. 4, the moving distance MD per unit time of the carriage 22 is represented by "32", which is the number of dots of the boundary region forming dots IDS arranged in the main scanning direction H1. For this reason, the wavelengths λ of the plurality of pattern waveforms SW1, SW2, SW3, SW4 are represented by "32", which is the number of dots of the boundary region forming dots IDS arranged in the main scanning direction H1. Also, the wavelengths λ of the plurality of pattern waveforms SW1, SW2, SW3, SW4 are set to multiples of the number of the plurality of pattern waveforms SW1, SW2, SW3, SW4. For example, when the number of the plurality of pattern waveforms SW1, SW2, SW3, SW4 is "4", the wavelengths λ of the plurality of pattern waveforms SW1, SW2, SW3, SW4 are set to "32", which is a multiple of "4".

[0041] The amplitudes A of the plurality of pattern waveforms SW1, SW2, SW3, SW4 are set to values corresponding to, for example, half of the boundary region width BAW indicating the width in the sub-scanning direction H2 of the boundary region BA between the unit images GA on the medium W. The boundary region width BAW is represented by the number of dots of the boundary region forming dots IDS arranged in the sub-scanning direction H2 within the boundary region BA. In the example of FIG. 4, the boundary region width BAW is represented by "10", which is the number of dots of the boundary region forming dots IDS arranged in the sub-scanning direction H2 within the boundary region BA. For this reason, the amplitudes A of the plurality of pattern waveforms SW1, SW2, SW3, SW4 are represented by "5", which corresponds to half of "10", which is the number of dots of the boundary region forming dots IDS arranged in the sub-scanning direction H2 within the boundary region BA.

[0042] The phase difference of the phase α in the plurality of pattern waveforms SW1, SW2, SW3, SW4 is set to a value obtained by dividing 2π by the number of the plurality of pattern waveforms SW1, SW2, SW3, SW4. For example, when the number of the plurality of pattern waveforms SW1, SW2, SW3, SW4 is "4", the phase difference of the phase α in the plurality of pattern waveforms SW1, SW2, SW3, SW4 is "2π / 4".

[0043] As described above, for each of the plurality of ink dot IDs included in each ink dot data DID for one pass operation, the computer 6 sets the positions in the sub-scanning direction H2 of each of the plurality of boundary end dot IDS1 arranged in the main scanning direction H1 among the boundary region forming dots IDS for forming the boundary region BA, to positions corresponding to a plurality of pattern waveforms SW1, SW2, SW3, SW4 with different phases α. As a result, among the plurality of ink dot IDs included in each ink dot data DID for one pass operation, the plurality of boundary end dot IDS1 that define the boundary B in the sub-scanning direction H2 between adjacent unit images GA on the medium W are restricted such that dots adjacent in the main scanning direction H1 are arranged linearly along the main scanning direction H1, and are restricted from being arranged along a single waveform. For this reason, the plurality of boundary end dot IDS1 can be irregularly dispersed in the sub-scanning direction H2. As a result, it is possible to suppress the occurrence of streak-like density unevenness and the like derived from the plurality of boundary end dot IDS1 in the boundary region BA between the unit images GA on the medium W, and thus it is possible to suppress a decrease in the quality of the image formed on the medium W.

[0044] The plurality of pattern waveforms SW1, SW2, SW3, SW4 with different phases α may each be set such that the wavelength λ is the same and the amplitude A is the same. When the wavelength λ is the same in the plurality of pattern waveforms SW1, SW2, SW3, SW4, the period is also the same. By setting the positions in the sub-scanning direction H2 of each of the plurality of boundary end dot IDS1 to positions corresponding to the plurality of pattern waveforms SW1, SW2, SW3, SW4 with the same wavelength λ, the same amplitude A, and different phases α, it is possible to suppress the occurrence of interference fringes in the boundary region BA between the unit images GA on the medium W.

[0045] The process of the computer 6 when setting the positions in the sub-scanning direction H2 of each of the plurality of boundary end dots IDS1 to positions corresponding to the plurality of pattern waveforms SW1, SW2, SW3, SW4 will be described in more detail with reference to FIG. 4. In the following description, when distinguishing the plurality of pattern waveforms SW1, SW2, SW3, SW4, they are referred to as the first pattern waveform SW1, the second pattern waveform SW2, the third pattern waveform SW3, and the fourth pattern waveform SW4.

[0046] The computer 6 sets the positions in the sub-scanning direction H2 of each of the plurality of boundary end dots IDS1 to positions corresponding to the plurality of pattern waveforms SW1, SW2, SW3, SW4 with different phases α so that the plurality of boundary end dots IDS1 that define the boundary B in the sub-scanning direction H2 between the unit images GA adjacent to each other in the sub-scanning direction H2 on the medium W are arranged along a single waveform. In this case, in all combinations of the boundary end dots IDS1 adjacent to each other in the main scanning direction H1, the positions in the sub-scanning direction H2 of the boundary end dots IDS1 adjacent to each other in the main scanning direction H1 do not necessarily have to be positions corresponding to different pattern waveforms SW1, SW2, SW3, SW4. That is, when setting the positions in the sub-scanning direction H2 of each of the plurality of boundary end dots IDS1 to positions corresponding to the plurality of pattern waveforms SW1, SW2, SW3, SW4, the computer 6 may allow the positions in the sub-scanning direction H2 of the boundary end dots IDS1 adjacent to each other in the main scanning direction H1 to be positions corresponding to the same pattern waveform in a part of the region in the main scanning direction H1.

[0047] In this embodiment, the computer 6 may set the positions in the sub-scanning direction H2 of each of the plurality of boundary end dots IDS1 such that, at the plurality of boundary end dots IDS1, the positions in the sub-scanning direction H2 of the boundary end dots IDS1 adjacent to each other in the main scanning direction H1 are positions corresponding to different pattern waveforms SW1, SW2, SW3, and SW4. For example, for the plurality of boundary end dots IDS1 corresponding to the first unit image GA, the computer 6 sets the sub-scanning coordinate I that defines the position in the sub-scanning direction H2 of the boundary end dot IDS1 with the main scanning coordinate J being "0" to "5" corresponding to the first pattern waveform SW1. For the sub-scanning coordinate I of the boundary end dot IDS1 with the main scanning coordinate J being "1" adjacent to "0", the computer 6 sets it to "10" after "9" corresponding to the second pattern waveform SW2 having a phase α different from that of the first pattern waveform SW1. Similarly, for the plurality of boundary end dots IDS1 corresponding to the second unit image GA, the computer 6 sets the sub-scanning coordinate I that defines the position in the sub-scanning direction H2 of the boundary end dot IDS1 with the main scanning coordinate J being "0" to "4" corresponding to the first pattern waveform SW1. For the sub-scanning coordinate I of the boundary end dot IDS1 with the main scanning coordinate J being "1" adjacent to "0", the computer 6 sets it to "9" corresponding to the second pattern waveform SW2 having a phase α different from that of the first pattern waveform SW1. For the plurality of boundary end dots IDS1 corresponding to each of the first and second unit images GA, the computer 6 repeats the above processing so that the positions in the sub-scanning direction H2 of the boundary end dots IDS1 adjacent to each other in the main scanning direction H1 are positions corresponding to different pattern waveforms SW1, SW2, SW3, and SW4, thereby setting the position in the sub-scanning direction H2 of each of the plurality of boundary end dots IDS1. Thereby, the plurality of boundary end dots IDS1 can be more reliably and irregularly dispersed in the sub-scanning direction H2. For this reason, it is possible to more reliably suppress the occurrence of streak-like density unevenness and the like derived from the plurality of boundary end dots IDS1 in the boundary region BA between the unit images GA on the medium W.

[0048] Further, the computer 6 may divide the coordinate group of the main scanning coordinates J that define the positions of the plurality of boundary end dots IDS1 in the main scanning direction H1 into a plurality of regions including the coordinates of the number of the plurality of pattern waveforms SW1, SW2, SW3, SW4. In the example of FIG. 4, the computer 6 divides the total of 32 coordinate groups of "0, 1, 2, ···, 29, 30, 31" in the main scanning coordinates J into "8" regions. Each of the "8" regions contains "4" coordinates corresponding to the number of the plurality of pattern waveforms SW1, SW2, SW3, SW4. In this case, the computer 6 sets region coordinates K indicating "4" coordinates for each of the "8" regions corresponding to the main scanning coordinates J. In the region coordinates K, each of the "8" regions contains a total of "4" coordinates of "0, 1, 2, 3". That is, the region coordinates K corresponding to the main scanning coordinates J are "0, 1, 2, 3, ···, 0, 1, 2, 3", and the coordinates of "0, 1, 2, 3" are repeated by the number of divided regions.

[0049] When the computer 6 sets the region coordinates K by dividing the coordinate group of the main scanning coordinates J into a plurality of regions, the computer 6 sets the positions of the plurality of boundary end dots IDS1 in the sub-scanning direction H2 so that the positions of the plurality of boundary end dots IDS1 belonging to each of the plurality of regions in the sub-scanning direction H2 become positions corresponding to different pattern waveforms SW1, SW2, SW3, SW4.

[0050] Specifically, for the sub-scanning coordinate I that defines the position in the sub-scanning direction H2 of the boundary end dot IDS1 where the region coordinate K corresponding to the main scanning coordinate J is "0", the computer 6 sets it according to the first pattern waveform SW1. For the sub-scanning coordinate I that defines the position in the sub-scanning direction H2 of the boundary end dot IDS1 where the region coordinate K corresponding to the main scanning coordinate J is "1" adjacent to "0", the computer 6 sets it according to the second pattern waveform SW2 that has a phase α different from that of the first pattern waveform SW1. For the sub-scanning coordinate I that defines the position in the sub-scanning direction H2 of the boundary end dot IDS1 where the region coordinate K corresponding to the main scanning coordinate J is "2" adjacent to "1", the computer 6 sets it according to the third pattern waveform SW3 that has a phase α different from those of the first pattern waveform SW1 and the second pattern waveform SW2. For the sub-scanning coordinate I that defines the position in the sub-scanning direction H2 of the boundary end dot IDS1 where the region coordinate K corresponding to the main scanning coordinate J is "3" adjacent to "2", the computer 6 sets it according to the fourth pattern waveform SW4 that has a phase α different from those of the first pattern waveform SW1, the second pattern waveform SW2, and the third pattern waveform SW3.

[0051] When the plurality of pattern waveforms SW1, SW2, SW3, SW4 are sine wave waveforms, the computer 6 sets the position in the sub-scanning direction H2 of each of the plurality of boundary end dots IDS1 according to the following formula (2).

[0052]

Equation

[0053] In formula (2), "I" represents the sub-scanning coordinate I, "J" represents the main scanning coordinate J, "K" represents the region coordinate K, "SWN" represents the number of the plurality of pattern waveforms SW1, SW2, SW3, SW4, "λ" represents the wavelength λ of the plurality of pattern waveforms SW1, SW2, SW3, SW4, and "A" represents the amplitude A of the plurality of pattern waveforms SW1, SW2, SW3, SW4. Also, in formula (2), "round" indicates rounding off the digits after the decimal point.

[0054] Assume a case where the number SWN of a plurality of pattern waveforms SW1, SW2, SW3, SW4 is "4", the wavelength λ is "32", and the amplitude A is "5". In this case, for the sub-scanning coordinate I that defines the position in the sub-scanning direction H2 of the boundary end dot IDS1 where the main scanning coordinate J is "0" and the region coordinate K is "0", for the boundary end dot IDS1 corresponding to the first unit image GA, it is set to "5" according to the above formula (2) corresponding to the first pattern waveform SW1, and for the boundary end dot IDS1 corresponding to the second unit image GA, it is set to "4" adjacent to it in the sub-scanning direction H2 with respect to "5". Similarly, for the sub-scanning coordinate I of the boundary end dot IDS1 where the main scanning coordinate J is "1" adjacent to "0" and the region coordinate K is "1" adjacent to "0", for the boundary end dot IDS1 corresponding to the first unit image GA, it is set to "10" according to the above formula (2) corresponding to the second pattern waveform SW2, and for the boundary end dot IDS1 corresponding to the second unit image GA, it is set to "9" adjacent to it in the sub-scanning direction H2 with respect to "10". Also, for the sub-scanning coordinate I of the boundary end dot IDS1 where the main scanning coordinate J is "2" adjacent to "1" and the region coordinate K is "2" adjacent to "1", for the boundary end dot IDS1 corresponding to the first unit image GA, it is set to "3" according to the above formula (2) corresponding to the third pattern waveform SW3, and for the boundary end dot IDS1 corresponding to the second unit image GA, it is set to "2" adjacent to it in the sub-scanning direction H2 with respect to "3". Further, for the sub-scanning coordinate I of the boundary end dot IDS1 where the main scanning coordinate J is "3" adjacent to "2" and the region coordinate K is "3" adjacent to "2", for the boundary end dot IDS1 corresponding to the first unit image GA, it is set to "1" according to the above formula (2) corresponding to the fourth pattern waveform SW4, and for the boundary end dot IDS1 corresponding to the second unit image GA, it is set to "0" adjacent to it in the sub-scanning direction H2 with respect to "1".

[0055] When the computer 6 sets the area coordinates K by dividing the coordinate group of the main scanning coordinates J into a plurality of areas, for a plurality of boundary end dots IDS1 corresponding to each of the first and second unit images GA, the positions of each boundary end dot IDS1 belonging to each of the plurality of areas in the sub-scanning direction H2 are set to positions corresponding to different pattern waveforms SW1, SW2, SW3, SW4. By repeatedly performing the process according to the above formula (2) for each area, the positions of each of the plurality of boundary end dots IDS1 in the sub-scanning direction H2 are set. As a result, the plurality of boundary end dots IDS1 can be more reliably and irregularly dispersed in the sub-scanning direction H2. For this reason, it is possible to more reliably suppress the occurrence of streak-like density unevenness and the like derived from the plurality of boundary end dots IDS1 in the boundary area BA between the unit images GA on the medium W.

[0056] When the ink head 3 in the inkjet printer 2 includes a plurality of individual heads 31 capable of ejecting each of a plurality of colors of ink, the computer 6 creates ink dot data DID for each color corresponding to each of the plurality of individual heads 31 for each pass operation. The computer 6 sets the positions of the plurality of boundary end dots IDS1 in the sub-scanning direction H2 in the ink dot data DID for each color to positions corresponding to the plurality of pattern waveforms SW1, SW2, SW3, SW4. In this case, the computer 6 changes at least one of the phase α and the wavelength λ in the plurality of pattern waveforms SW1, SW2, SW3, SW4 for each ink dot data DID for each color. Thereby, when forming a plurality of color images on the medium W, it is possible to suppress the occurrence of streak-like density unevenness and the like derived from the plurality of boundary end dots IDS1 in the boundary area BA between the unit images GA on the medium W.

[0057] When setting the positions of a plurality of boundary end dots IDS1 in the sub-scanning direction H2 of various color ink dot data DID to positions corresponding to a plurality of pattern waveforms SW1, SW2, SW3, SW4, the computer 6 changes at least one of the phase α and the wavelength λ in the plurality of pattern waveforms SW1, SW2, SW3, SW4 so as to be different for adjacent hues when arranging the various colors on the hue circle for each color ink dot data DID. Here, black, white, and gray which is an intermediate color are achromatic colors having no hue and chroma among the three attributes of color: lightness, hue, and chroma. For this reason, achromatic colors are usually not included in the hue circle. Therefore, the colors targeted when the computer 6 uses the hue circle are chromatic colors other than achromatic colors.

[0058] As shown in FIG. 3, when creating ink dot data DID for each pass operation in the ink data creation step s2, the computer 6 performs a treatment liquid data creation process of creating treatment liquid dot data DRD indicating data of a pattern of treatment liquid dots to be formed on the medium W in accordance with the discharge of the treatment liquid by the treatment liquid head 4 based on the ink dot data DID for each pass operation (treatment liquid data creation step s3). The computer 6 creates pretreatment liquid dot data DRD1 indicating data of a pattern of pretreatment liquid dots to be formed on the medium W in accordance with the discharge of the pretreatment liquid by the pretreatment liquid head 41 as the treatment liquid dot data DRD. Similarly, the computer 6 creates post-treatment liquid dot data DRD2 indicating data of a pattern of post-treatment liquid dots to be formed on the medium W in accordance with the discharge of the post-treatment liquid by the post-treatment liquid head 42 as the treatment liquid dot data DRD. In the present embodiment, the computer 6 creates treatment liquid dot data DRD common to the pretreatment liquid dot data DRD1 and the post-treatment liquid dot data DRD2.

[0059] The computer 6 creates the processing liquid dot data DRD such that each processing liquid dot in the processing liquid dot data DRD includes at least a dot at the same position as each ink dot ID in the ink dot data DID. When the ink head 3 in the inkjet printer 2 includes a plurality of individual heads 31 capable of ejecting each of a plurality of colors of ink, the computer 6 creates the processing liquid dot data DRD based on the logical sum data obtained by taking the logical sum of the ink dot data DID for each color. In this case, the computer 6 creates the processing liquid dot data DRD such that each processing liquid dot in the processing liquid dot data DRD includes at least a dot at the same position as each ink dot ID in the logical sum data. Note that the computer 6 may create the processing liquid dot data DRD based on the image data DG.

[0060] The computer 6 creates the processing liquid dot data DRD in which processing liquid dots are arranged at the same positions as the respective ink dot IDs in the ink dot data DID, and processing liquid dots are also arranged in the regions around the respective ink dot IDs. In this case, similar to the case of the ink dot data DID, the computer 6 may set the positions in the sub-scanning direction H2 of each processing liquid dot corresponding to the plurality of boundary end dots IDS1 in the ink dot data DID to positions corresponding to the plurality of pattern waveforms SW1, SW2, SW3, SW4 among the plurality of processing liquid dots included in the processing liquid dot data DRD.

[0061] When creating the ink dot data DID and the processing liquid dot data DRD for each pass operation, the computer 6 transmits the created ink dot data DID and the processing liquid dot data DRD to the inkjet printer 2 (data transmission step s4).

[0062] When ink dot data DID and processing liquid dot data DRD are received in the inkjet printer 2 (data reception step s5), the printer control unit 5 executes a pass operation step s6 of causing the inkjet head 20 including the ink head 3 and the processing liquid head 4 mounted on the carriage 22 to perform a pass operation, and a conveyance step s7 of causing the conveyance unit 21 to perform a conveyance operation of the medium W, repeatedly. Thereby, the printer control unit 5 performs an image formation process of an image formation step of forming a plurality of unit images GA composed of a plurality of ink dot IDs corresponding to at least one pass operation in the sub-scanning direction H2 on the medium W. The printer control unit 5 determines whether or not the formation of the image on the medium W has been completed (determination step s8), and repeatedly performs the pass operation step s6 and the conveyance step s7 until the formation of the image is completed.

[0063] In the pass operation step s6, based on the ink dot data DID and the processing liquid dot data DRD, the printer control unit 5 moves the carriage 22 in the main scanning direction H1, discharges the pretreatment liquid from the pretreatment liquid head 41 (step s61), discharges the ink from the ink head 3 (step s62), and discharges the post-treatment liquid from the post-treatment liquid head 42 (step s63).

[0064] As described above, among the boundary region forming dots IDS for forming the boundary region BA in the plurality of ink dot IDs included in each ink dot data DID for each pass operation, a plurality of boundary end dots IDS1 that define the boundary B in the sub-scanning direction H2 between adjacent unit images GA on the medium W in the sub-scanning direction H2 are restricted from being arranged linearly along the main scanning direction H1 and from being arranged along a single waveform. For this reason, the plurality of boundary end dots IDS1 can be irregularly dispersed in the sub-scanning direction H2. As a result, it is possible to suppress the occurrence of streak-like density unevenness and the like derived from the plurality of boundary end dots IDS1 in the boundary region BA between the unit images GA on the medium W. Thereby, it is possible to suppress a decrease in the quality of the image formed on the medium W.

Explanation of Reference Numerals

[0065] 1 Inkjet recording system 2 Inkjet printer 3 Ink head 31 Individual head 5 Printer control unit (control unit) 6 Computer (dot data creation unit) DID Ink dot data GA unit image H1 Main scanning direction H2 Sub-scanning direction ID Ink dot IDS Boundary region forming dot IDS1 Boundary end dot W Medium (recording material)

Claims

1. an ink head that is movable in a main scanning direction and is capable of ejecting ink onto a recording material; a conveying section capable of conveying the recording material in a sub-scanning direction perpendicular to the main scanning direction; a control unit that performs an image formation process in which a pass operation in which the ink head is moved in the main scanning direction while ejecting the ink from the ink head to form a plurality of ink dots on the recording material, and a conveying operation of the recording material in the sub-scanning direction by the conveying unit are repeatedly performed, thereby forming a plurality of unit images, each of which is made up of a plurality of the ink dots corresponding to at least one pass operation, on the recording material in the sub-scanning direction; a dot data creating unit that performs an ink data creating process to create ink dot data indicating data of a pattern of a plurality of ink dots for forming each of a plurality of unit images on the recording material for each pass operation, the control unit causes the passing operation and the conveying operation to be performed in the image forming process such that a boundary area extending in the main scanning direction is formed on the recording material by partially overlapping the unit images adjacent to each other in the sub-scanning direction in the sub-scanning direction, In the ink data creation process, the dot data creation unit sets the sub-scanning direction position of each of a plurality of boundary end dots that are lined up in the main scanning direction and that define the boundary in the sub-scanning direction between the unit images adjacent in the sub-scanning direction on the recording material, among the plurality of ink dots included in each of the ink dot data for each pass operation, to positions corresponding to a plurality of pattern waveforms that have wavelengths corresponding to the main scanning direction and amplitudes corresponding to the sub-scanning direction and are different in phase.

2. 2. The inkjet recording system according to claim 1, wherein the dot data creation unit sets the sub-scanning direction positions of each of the plurality of boundary end dots such that the sub-scanning direction positions of adjacent boundary end dots in the main scanning direction correspond to different pattern waveforms.

3. The dot data creation unit Dividing a group of main scanning coordinates that define the positions of each of the plurality of boundary end dots in the main scanning direction into a plurality of regions including coordinates equal to the number of the plurality of pattern waveforms; 2. The inkjet recording system according to claim 1, wherein the sub-scanning direction position of each of the plurality of boundary end dots belonging to each of the plurality of regions is set so that the sub-scanning direction position of each of the plurality of boundary end dots corresponds to a different pattern waveform.

4. 2. The inkjet recording system according to claim 1, wherein the plurality of pattern waveforms have the same wavelength and the same amplitude.

5. the ink head includes a plurality of individual heads capable of ejecting each of the inks of a plurality of colors; The dot data creation unit, in the ink data creation process, creating the ink dot data for each color corresponding to each of the plurality of individual heads for each pass operation; 2. The inkjet recording system according to claim 1, wherein when the positions in the sub-scanning direction of the multiple boundary end dots in the ink dot data of each color are set to positions corresponding to the multiple pattern waveforms, at least one of the phase and the wavelength in the multiple pattern waveforms is changed for each of the ink dot data of each color.

6. 6. The inkjet recording system of claim 5, wherein, in the ink data creation process, when the dot data creation unit sets the positions in the sub-scanning direction of the multiple boundary end dots in the ink dot data of each color to positions corresponding to the multiple pattern waveforms, the dot data creation unit changes at least one of the phase and the wavelength in the multiple pattern waveforms for each ink dot data of each color so that adjacent hues are different when the colors are arranged on a hue wheel.

7. 7. The inkjet recording system according to claim 1, wherein the recording material is a cloth member made of a cloth material.

8. An inkjet recording method for recording an image on a recording material using an ink head movable in a main scanning direction, comprising: an image forming process in which a pass operation in which ink is ejected from the ink head while moving the ink head in the main scanning direction to form a plurality of ink dots on the recording material, and a transport operation in which the recording material is transported in a sub-scanning direction perpendicular to the main scanning direction, are repeatedly performed, thereby forming a plurality of unit images, each of which is made up of a plurality of ink dots corresponding to at least one pass operation, on the recording material in the sub-scanning direction; an ink data creating step of creating ink dot data representing data of a pattern of a plurality of ink dots for forming each of a plurality of unit images on the recording material for each pass operation; In the image forming step, the passing operation and the conveying operation are performed so that a boundary area extending in the main scanning direction is formed on the recording material by overlapping parts of the unit images adjacent to each other in the sub-scanning direction in the sub-scanning direction, and the boundary area extends in the main scanning direction. In the ink data creation process, among the multiple ink dots included in each of the ink dot data for one pass operation, the position in the sub-scanning direction of each of the multiple boundary end dots that are lined up in the main scanning direction and that define the boundary in the sub-scanning direction between the unit images adjacent in the sub-scanning direction on the recording material, is set to a position corresponding to a multiple pattern waveform having a wavelength corresponding to the main scanning direction and an amplitude corresponding to the sub-scanning direction and different phases.

Images