Inkjet recording apparatus and inkjet recording method

Abstract

Provided is an inkjet recording device that includes a carriage on which a pretreatment head, an ink head, and a posttreatment head are mounted and that moves in the main scanning direction, and that can reduce the reduction in ink color density caused by the posttreatment liquid directly acting on the pretreatment liquid. [Solution] The inkjet printer 1 includes a work transport unit 20 that transports a work W in a transport direction F, a carriage 3 that moves back and forth in a main scanning direction S, a plurality of ink heads 4A to 4F that are mounted on the carriage 3 so as to be aligned in the main scanning direction S and eject ink for forming an image, and a pre-treatment head 5 and a post-treatment head 6 that eject non-color-forming pre-treatment liquid and post-treatment liquid, respectively. The plurality of ink heads include a plurality of same-color ink heads that are aligned in the transport direction F upstream of the post-treatment head 6 and eject ink of the same color.

Description

[Technical Field]

[0001] The present disclosure relates to an inkjet recording apparatus having an ink head mounted on a carriage that moves in a main scanning direction. [Background technology]

[0002] Inkjet recording devices such as inkjet printers are equipped with ink heads that eject ink for forming an image onto a recording medium. For example, when the recording medium is a fiber sheet such as a woven or knitted fabric, or a plastic sheet, it may be necessary to apply a pretreatment liquid and a posttreatment liquid to the recording medium before and after ejecting the ink onto the recording medium (see, for example, Patent Document 1). The pretreatment liquid is, for example, a treatment liquid that improves the fixation of the ink to the recording medium and the coagulation of the ink pigment. The posttreatment liquid is, for example, a treatment liquid that improves the robustness of the printed image. In this case, the inkjet recording device is equipped with, in addition to the ink heads, a treatment head that ejects the pretreatment liquid and the posttreatment liquid.

[0003] When the recording medium is wide, the ink head and each processing head are mounted on a carriage that moves back and forth in the main scanning direction. During recording processing, the recording medium is intermittently fed in a predetermined transport direction (sub-scanning direction), and the carriage moves back and forth in the main scanning direction while the recording medium is stopped. As the carriage moves, ink and processing liquid are ejected from the ink head and each processing head, respectively. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-147307 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present disclosure is to provide an inkjet recording device that includes a carriage that is mounted with a pre-treatment head, an ink head, and a post-treatment head and moves in the main scanning direction, and that can reduce the reduction in ink color density caused by the post-treatment liquid directly acting on the pre-treatment liquid. [Means for solving the problem]

[0006] An inkjet recording apparatus according to one aspect of the present disclosure includes a transport unit, a carriage, one or more ink heads, a treatment head, at least one pre-treatment head, and at least one post-treatment head. The transport unit transports a recording medium in a predetermined transport direction. The carriage reciprocates in a main scanning direction that intersects with the transport direction. The multiple ink heads are mounted on the carriage and eject inks, respectively. The at least one pre-treatment head is arranged upstream of the multiple ink heads in the transport direction and ejects a non-color-forming pre-treatment liquid. The at least one post-treatment head is arranged downstream of the multiple ink heads in the transport direction and ejects a non-color-forming post-treatment liquid. The multiple ink heads include multiple same-color ink heads arranged side by side in the transport direction and ejecting inks of the same color. [Effects of the Invention]

[0007] According to the present invention, an inkjet recording device can be provided which is equipped with a carriage that is mounted with a pre-treatment head, an ink head, and a post-treatment head and moves in the main scanning direction, and which can reduce the reduction in ink color density caused by the post-treatment liquid directly acting on the pre-treatment liquid. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing the overall configuration of an inkjet recording apparatus according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. [Figure 3]FIG. 3 is an enlarged perspective view of the carriage shown in FIG. [Figure 4] FIG. 4 is a schematic diagram showing the serial printing method employed in the first embodiment of the present disclosure. [Figure 5A] FIG. 5A is a schematic diagram showing the printing status during the forward and backward travel of the carriage. [Figure 5B] FIG. 5B is a schematic diagram showing the printing status during the forward and backward travel of the carriage. [Figure 6] FIG. 6 is a plan view schematically showing the arrangement of the ink heads and processing heads on the carriage shown in FIG. [Figure 7] FIG. 7 is a plan view schematically showing the positional relationship between the nozzles of the ink head and the processing head shown in FIG. [Figure 8] FIG. 8 is a block diagram of the inkjet recording apparatus according to the first embodiment of the present disclosure. [Figure 9] FIG. 9 is a schematic plan view showing the upstream ink head and the downstream ink head in the inkjet recording apparatus according to the first embodiment of the present disclosure. [Figure 10] FIG. 10 is a schematic diagram illustrating the landing of ink and each treatment liquid on image dots near the head boundary in the inkjet recording apparatus according to the first embodiment of the present disclosure. [Figure 11] FIG. 11 is a schematic diagram illustrating the landing of ink and each treatment liquid on image dots near the head boundary in the inkjet recording apparatus according to the first embodiment of the present disclosure. [Figure 12] FIG. 12 is a schematic plan view showing an upstream ink head and a downstream ink head in an inkjet recording apparatus according to a second embodiment of the present disclosure. [Figure 13] FIG. 13 is a plan view that schematically shows the arrangement of ink heads and processing heads on a carriage in an inkjet recording apparatus according to a third embodiment of the present disclosure. [Figure 14] FIG. 14 is a plan view schematically showing the arrangement of ink heads and processing heads on a carriage in an inkjet recording apparatus according to a fourth embodiment of the present disclosure. [Figure 15] FIG. 15 is a plan view schematically showing the arrangement of ink heads and processing heads on a carriage in an inkjet recording apparatus according to a fifth embodiment of the present disclosure. [Figure 16] FIG. 16 is a plan view schematically showing the arrangement of ink heads and processing heads on a carriage in an inkjet recording apparatus according to a sixth embodiment of the present disclosure. [Figure 17] FIG. 17 is a plan view that schematically shows the arrangement of ink heads, processing heads, and sub-tanks on a carriage in an inkjet recording apparatus according to a sixth embodiment of the present disclosure. [Figure 18] FIG. 18 is a plan view schematically showing the arrangement of ink heads and processing heads on a carriage in another inkjet recording apparatus to be compared with each embodiment of the present disclosure. [Figure 19] FIG. 19 is a schematic diagram for explaining the landing of ink and each treatment liquid on image dots near the head boundary in the inkjet recording apparatus shown in FIG. [Figure 20] FIG. 20 is a schematic diagram for explaining the impact of ink and each treatment liquid on image dots near the head boundary in the inkjet recording apparatus shown in FIG. [Figure 21] FIG. 21 is a plan view schematically showing the arrangement of ink heads and processing heads on a carriage in another inkjet recording apparatus to be compared with each embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] Inkjet recording apparatuses according to embodiments of the present disclosure will be described below with reference to the drawings. In these embodiments, an inkjet printer equipped with an ink head that ejects ink for forming an image onto a wide, long recording medium will be exemplified as a specific example of an inkjet recording apparatus. Inkjet printers are suitable for digital textile printing, which uses an inkjet method to print images such as letters and patterns onto a recording medium made of fabric such as woven or knitted fabric. Of course, the inkjet recording apparatus according to the present disclosure can also be used to print various inkjet images on recording media such as paper sheets and resin sheets.

[0010] [Overall configuration of inkjet printer] Fig. 1 is a perspective view showing the overall configuration of an inkjet printer 1 according to a first embodiment of the present disclosure, and Fig. 2 is a schematic cross-sectional view taken along line II-II in Fig. 1. The inkjet printer 1 is a printer that prints images on a wide and long workpiece W (recording medium) using an inkjet method, and includes a device frame 10, and a workpiece transport unit 20 (transport unit) and carriage 3 that are incorporated into this device frame 10. In this embodiment, the left-to-right direction is the main scanning direction S (Fig. 3) when printing on the workpiece W, and the direction from rear to front is the sub-scanning direction (direction F for transporting the workpiece W).

[0011] The device frame 10 forms a framework for mounting various components of the inkjet printer 1. The work transport unit 20 is a mechanism that intermittently feeds (transports) the work W so that the work W progresses in a transport direction F from rear to front in the printing area where the inkjet printing process is performed. The carriage 3 is equipped with an ink head 4, a pre-processing head 5, a post-processing head 6, and a sub-tank 7, and moves back and forth in a main scanning direction S (left and right direction) that intersects with the transport direction F of the work W during the inkjet printing process.

[0012] The device frame 10 includes a central frame 111, a right frame 112, and a left frame 113. The central frame 111 forms a framework for mounting various components of the inkjet printer 1, and has a left-to-right width corresponding to the work transport section 20. The right frame 112 and the left frame 113 are erected to the right and left of the central frame 111, respectively. Between the right frame 112 and the left frame 113 is the printing area 12 where printing processing is performed on the work W.

[0013] The right frame 112 forms the maintenance area 13. The maintenance area 13 is an area where the carriage 3 is retracted when the printing process is not being performed. In the maintenance area 13, cleaning processes, purging processes, etc. are performed on the nozzles (ejection holes) of the ink head 4, pre-processing head 5, and post-processing head 6, and caps are fitted. The left frame 113 forms the return area 14 for the carriage 3. The return area 14 is an area where the carriage 3 temporarily enters when it performs a main scan in the opposite direction after performing a main scan in the opposite direction across the printing area 12 from right to left during the printing process.

[0014] A carriage guide 15 is attached to the upper side of the device frame 10 to allow the carriage 3 to reciprocate in the left-right direction. The carriage guide 15 is a flat, plate-shaped member that is long in the left-right direction, and is disposed above the work transport unit 20. A timing belt 16 (moving member) is attached to the carriage guide 15 so as to be able to move in a circular motion in the left-right direction (main scanning direction). The timing belt 16 is an endless belt, and is driven by a carriage drive unit 3S, which will be described later, to move in a circular motion in the left or right direction.

[0015] The carriage guide 15 is equipped with a pair of upper and lower guide rails 17 (holding members) that extend parallel to the left and right and that hold the carriage 3 in a state that allows it to move back and forth in the main scanning direction S. The carriage 3 is engaged with the guide rails 17. The carriage 3 is also fixed to a timing belt 16. As the timing belt 16 moves orbitally left or right, the carriage 3 moves left or right along the carriage guide 15 while being guided by the guide rails 17.

[0016] Referring primarily to FIG. 2, the work transport section 20 includes a feed roller 21 that pays out the work W before printing, and a take-up roller 22 that takes up the work W after printing. The feed roller 21 is located at the rear lower part of the device frame 10, and is a take-up shaft for the feed roll WA, which is a wound body of the work W before printing. The take-up roller 22 is located at the front lower part of the device frame 10, and is a take-up shaft for the take-up roll WB, which is a wound body of the work W after the printing process. A first motor M1 is attached to the take-up roller 22, which drives the take-up roller 22 to rotate about its axis and performs the operation of winding up the work W.

[0017] The path between the delivery roller 21 and the take-up roller 22 and passing through the printing area 12 is the transport path for the workpiece W. Arranged on this transport path, in order from upstream, are a first tension roller 23, a work guide 24, a transport roller 25 and a pinch roller 26, a turn-back roller 27, and a second tension roller 28. The first tension roller 23 applies a predetermined tension to the workpiece W on the upstream side of the transport roller 25. The work guide 24 changes the transport direction of the workpiece W from upward to forward, allowing the workpiece W to enter the printing area 12.

[0018] The transport roller 25 is a roller that generates a transport force that intermittently feeds the workpiece W in the printing area 12. The transport roller 25 is driven to rotate around its axis by the second motor M2, and intermittently transports the workpiece W forward (predetermined transport direction F) so that the workpiece W passes through the printing area 12 (image forming position) facing the carriage 3. The pinch roller 26 is disposed so as to face the transport roller 25 from above, and forms a transport nip portion with the transport roller 25.

[0019] The turn-back roller 27 changes the transport direction of the workpiece W that has passed through the printing area 12 from forward to downward, and guides the workpiece W after printing to the take-up roller 22. The second tension roller 28 applies a predetermined tension to the workpiece W downstream of the transport roller 25. A platen 29 is disposed below the transport path of the workpiece W in the printing area 12.

[0020] The carriage 3 is supported at one end by a guide rail 17 and moves back and forth in a main scanning direction S (left and right in this embodiment) that intersects (orthogonal in this embodiment) with the transport direction F. The carriage 3 comprises a carriage frame 30, and an ink head 4, a pre-processing head 5, a post-processing head 6, and a sub-tank 7 that are mounted on the carriage frame 30. The carriage frame 30 includes a head support frame 31 and a back frame 32 (engagement portion).

[0021] The head support frame 31 is a horizontal plate that holds the heads 4 to 6. The back frame 32 is a vertical plate that extends upward from the rear end edge of the head support frame 31. As described above, the timing belt 16 is fixed to the back frame 32. The guide rail 17 is engaged with the back frame 32. That is, in this embodiment, the back frame 32 is an engagement portion that is held in a cantilevered state by the guide rail 17. The head support frame 31 is a horizontal plate whose rear end side is supported in a cantilevered state by the guide rail 17 by the engagement portion.

[0022] The cantilevered state refers to a state in which the engagement portion (back frame 32) of the carriage 3 is located only on one side, either upstream or downstream from the center of the carriage 3 in the transport direction F, and no other engagement portion is located on the opposite side of the side where the engagement portion is located. The engagement portion is a portion that is held by the guide rail 17, which is a holding member. The engagement portion may also be located outside the range in which the ink head 4 and processing head are located in the transport direction F. In other words, the engagement portion may be located only on the upstream side or only on the downstream side of the range in which the ink head 4 and processing head are located in the transport direction F.

[0023] [Carriage Details] The carriage 3 will now be described in further detail. Fig. 3 is an enlarged perspective view of the carriage 3 shown in Fig. 1. Fig. 3 shows the transport direction F (sub-scanning direction) of the workpiece W and the main scanning direction S, which is the direction of movement of the carriage 3. Fig. 3 shows an example in which the carriage 3 is equipped with a plurality of ink heads 4 that eject ink for image formation onto the workpiece W, a pre-treatment head 5 and a post-treatment head 6 that eject non-color-forming treatment liquid, and a plurality of sub-tanks 7 that supply the ink and treatment liquid to these heads 4 to 6.

[0024] Each ink head 4 has a number of nozzles (ink ejection holes) that eject ink droplets using an ejection method such as a piezoelectric method using a piezoelectric element or a thermal method using a heating element, and ink passages that guide the ink to the nozzles. For example, a water-based pigment ink containing a water-based solvent, pigment, and binder resin can be used as the ink. In this embodiment, the multiple ink heads 4 include first to sixth ink heads 4A to 4F, each of which ejects six different color inks. For example, the first ink head 4A ejects orange ink, the second ink head 4B ejects green ink, the third ink head 4C ejects yellow ink, the fourth ink head 4D ejects red ink, the fifth ink head 4E ejects blue ink, and the sixth ink head 4F ejects black ink.

[0025] The ink heads 4A to 4F of each color are mounted on the head support frame 31 of the carriage 3 so as to be aligned in the main scanning direction S. Each of the ink heads 4A to 4F of each color has two heads. For example, the first ink head 4A is composed of an upstream ink head 4A1 located upstream in the transport direction F and a downstream ink head 4A2 located downstream of the upstream ink head 4A1 and shifted to the left in the main scanning direction S. The ink heads 4B to 4F of the other colors are similar. Each of the upstream ink heads of the ink heads 4B to 4F is aligned in a line in the main scanning direction S at the same position as the upstream ink head 4A1 in the transport direction F, and each downstream ink head is aligned in a line in the main scanning direction S at the same position as the downstream ink head 4A2 in the transport direction F. In this embodiment, each line of ink heads 4 includes one ink head 4A to 4F of each color, but a line may include two or more ink heads of the same color.

[0026] In the following description, two ink heads of each color 4A-4F arranged side by side in the transport direction may be referred to as "same-color ink heads." Each of the ink heads 4A-4F of each color may be referred to as a set of same-color ink heads, and the ink heads 4A-4F may be collectively referred to as "multiple sets of same-color ink heads." The multiple sets of same-color ink heads are arranged side by side in the main scanning direction S, and each ejects ink of a different color.

[0027] The pre-treatment head 5 and post-treatment head 6 are disposed at different positions from the ink heads 4 in the transport direction F. The pre-treatment head 5 is disposed upstream of the ink heads 4 in the transport direction F. FIG. 3 shows an example in which one pre-treatment head 5 is disposed near the right end of the array of ink heads 4. Similarly, the post-treatment head 6 is disposed downstream of the ink heads 4 in the transport direction F. FIG. 3 shows an example in which one post-treatment head 6 is disposed at the right end of the array of ink heads 4. In other embodiments, multiple pre-treatment heads 5 or multiple post-treatment heads 6 may be disposed. That is, the carriage 3 is equipped with at least one pre-treatment head 5 and at least one post-treatment head 6.

[0028] As used in the above explanation, a series of heads along the main scanning direction S, which is made up of ink heads 4 and post-processing heads 6, is referred to as a row of heads, or simply as a row. Also, a series of heads along the transport direction F, which is made up of ink heads 4, pre-processing heads 5, and post-processing heads 6, is referred to as a row of heads, or simply as a row.

[0029] The pretreatment head 5 ejects a pretreatment liquid to perform a predetermined pretreatment on the workpiece W. The pretreatment liquid is ejected from the ink head 4 onto a position on the workpiece W to which ink has not yet been ejected from the ink head 4. The pretreatment liquid is a non-color-forming treatment liquid that does not develop color even when it adheres to the workpiece W, and is a treatment liquid that exhibits functions such as increasing the fixation of ink to the workpiece W or the coagulation of ink pigments. Examples of such pretreatment liquids that can be used include a treatment liquid in which a binder resin is blended into a solvent, or a treatment liquid in which a positively charged cationic resin is blended into a solvent.

[0030] The post-treatment head 6 ejects a post-treatment liquid to perform a predetermined post-treatment on the workpiece W to which ink has adhered. The post-treatment liquid is ejected from the post-treatment head 6 onto a position on the workpiece W after the ink has been ejected from the ink head 4. The post-treatment liquid is a non-color-forming treatment liquid that does not develop color even when it adheres to the workpiece W, and has the function of improving the fixation and robustness (resistance to rubbing and scraping) of the ink image printed on the workpiece W by the ink head 4. A silicone-based treatment liquid or the like can be used as such a post-treatment liquid. Note that the post-treatment liquid and the pre-treatment liquid are different treatment liquids. Specifically, the components contained in the post-treatment liquid and the pre-treatment liquid are different.

[0031] Here, a non-color-forming treatment liquid refers to a treatment liquid that, when printed alone on a recording medium, is not perceived as having a color by the naked eye. Colors here include colors with a saturation of zero, such as black, white, and gray. A non-color-forming treatment liquid is essentially a transparent liquid; however, when viewed in its liquid form, for example, 1 liter of treatment liquid may not be completely transparent, but may appear slightly white. Such colors are so faint that, when printed alone on a recording medium, they are not perceived as having a color by the naked eye. Note that, depending on the type of treatment liquid, when printed alone on a recording medium, changes such as gloss may appear on the recording medium, but such a state is not considered color-forming.

[0032] In this embodiment, the pre-treatment liquid and the post-treatment liquid may be ejected onto almost the entire surface of the workpiece W, or the pre-treatment liquid and the post-treatment liquid may be ejected selectively in accordance with the image to be printed, similar to ink.

[0033] Next, a case where the pretreatment liquid and the posttreatment liquid are selectively ejected will be described. As described above, the pretreatment liquid, ink, and posttreatment liquid are ejected in this order onto the portion of the workpiece W where a color is to be printed in accordance with the image. In this case, the ink may be of one color or multiple colors. In portions where no color is to be printed, i.e., portions where no ink is ejected, the pretreatment liquid and the posttreatment liquid are basically not ejected either. Note that, in order to adjust the image quality of the image to be printed and the texture of the workpiece W, the selection of ejection of the pretreatment liquid and the posttreatment liquid may be made to differ from the ejection of the ink.

[0034] Openings 31H (Fig. 3) are provided at the locations where the heads are arranged in the head support frame 31. The ink heads 4A to 4F, pre-processing head 5, and post-processing head 6 are assembled to the head support frame 31 so as to fit into the respective openings 31H. Nozzles arranged on the lower end surface of each of the heads 4, 5, and 6 are exposed from each opening 31H.

[0035] The sub-tanks 7 are supported by the carriage 3 above the heads 4, 5, and 6 via a holding frame (not shown). A sub-tank 7 is provided corresponding to each of the heads 4, 5, and 6. Each sub-tank 7 is supplied with ink or treatment liquid from a cartridge (not shown) or a main tank that contains the ink and treatment liquid. Each sub-tank 7 supplies the ink or treatment liquid to each of the heads 4, 5, and 6. Each sub-tank 7 and the heads 4, 5, and 6 are connected by pipes (not shown in FIG. 3) (P1, P2, and P3 shown in FIG. 17).

[0036] As described above, the inkjet printer 1 according to this embodiment is an all-in-one printer in which three types of heads - the ink head 4, pre-treatment head 5, and post-treatment head 6 - are mounted on a single carriage 3. With this inkjet printer 1, for example, in the printing process of inkjet printing onto fabric in digital textile printing, the process of ejecting the pre-treatment liquid and the process of ejecting the post-treatment liquid can be carried out in an integrated manner. This makes it possible to simplify the textile printing process and make the textile printing device more compact.

[0037] [Print method] Next, the printing method performed by the inkjet printer 1 according to this embodiment will be described. The inkjet printer 1 performs printing processing on the workpiece W using a serial printing method. Figure 4 is a schematic diagram showing the serial printing method. In Figure 4, the carriage 3 is depicted in a simplified manner, with the pre-processing head 5 and post-processing head 6 omitted.

[0038] If the workpiece W is wide, it is not possible to print while continuously feeding the workpiece W. The serial printing method is a printing method in which a carriage 3 carrying ink heads 4 of each color moves back and forth in the main scanning direction S, and intermittently feeds the workpiece W in the transport direction F, repeatedly. Here, the ink heads 4 are assumed to have a predetermined printing width Pw in the transport direction F. The printing width Pw is approximately equal to the length in the transport direction F of the arrangement area of ​​the ink ejection nozzles of the ink heads 4. Note that in Figure 4 and Figures 5A and 5B described below, the length in the transport direction F of each head is depicted as approximately equal to the printing width Pw. In reality, the length in the transport direction F of each head is greater than the printing width Pw and the length in the transport direction F of the arrangement area of ​​the ejection nozzles.

[0039] FIG. 4 shows the state in which the carriage 3 moves in the forward direction SA in the main scanning direction S and has completed printing of a strip-shaped image G1 with a printing width Pw. During this main scanning in the forward direction SA, the feeding of the workpiece W is stopped. After printing the strip-shaped image G1, the workpiece W is sent out in the transport direction F by a pitch corresponding to the printing width Pw. At this time, the carriage 3 waits in the return area 14 on the left end side. After sending out the workpiece W, the carriage 3 returns in the return direction SB as the timing belt 16 moves in the reverse direction. The workpiece W is in a stationary state. Then, as shown in FIG. 4, the carriage 3 moves in the return direction SB and prints a strip-shaped image G2 with a printing width Pw upstream of the strip-shaped image G1. Similar operations are repeated thereafter.

[0040] 5A and 5B are schematic diagrams showing the printing status of the carriage 3 on its forward and return passes. The ink head 4, pre-treatment head 5, and post-treatment head 6 mounted on the carriage 3 are shown in simplified form. The ink head 4 includes first, second, third, and fourth ink heads 4A, 4B, 4C, and 4D for ejecting ink of different colors (first, second, third, and fourth), respectively. These first to fourth ink heads 4A to 4D are aligned in a line in the main scanning direction S. The pre-treatment head 5 is located upstream of the ink head 4 in the transport direction F, and the post-treatment head 6 is located downstream. As with the case described with reference to FIG. 4, the workpiece W is sent in the transport direction F between the printing on the forward pass and the printing on the return pass. The distance traveled in the transport direction F is the spacing pitch (head pitch) between adjacent heads in the transport direction F. This distance also corresponds to the printing width Pw of each head 4, 5, and 6.

[0041] 5A shows a state in which the carriage 3 is performing a printing operation (outgoing main scanning) while moving in the outgoing direction SA in the main scanning direction S. Area A4 on the workpiece W is an area that faces the pretreatment head 5 mounted on the most upstream side of the carriage 3. During this outgoing main scanning, a pretreatment layer Lpre is formed on area A4 by the pretreatment liquid ejected from the pretreatment head 5.

[0042] Region A3 is one head pitch downstream of region A4 and faces the ink head 4. A pre-treatment layer Lpre has already been formed on region A3 over the entire length in the main scanning direction by the previous backward main scanning. During this forward main scanning, first, second, third, and fourth ink layers LCA, LCB, LCC, and LCD are formed on the pre-treatment layer Lpre in region A3 by the first to fourth color inks ejected sequentially in the aligned order of the first to fourth ink heads 4A to 4D. Note that, for ease of understanding, FIG. 5A illustrates the fourth to first ink layers LCD to LCA as if they were stacked sequentially, but they are not actually stacked. Note that the pre-treatment layer Lpre described above and the post-treatment layer Lpos described below are not formed on the workpiece W either.

[0043] Region A2 is one head pitch downstream of region A3 and faces the post-processing head 6 mounted on the most downstream side of the carriage 3. A pre-processing layer Lpre formed by the previous outgoing main scan and first to fourth ink layers LCA to LCD formed by the previous homeward main scan have already been formed in region A2 over the entire length in the main scanning direction. During this outgoing main scan, a post-processing layer Lpos is formed on the first to fourth ink layers LCA to LCD in region A2 by the post-processing liquid ejected from the post-processing head 6.

[0044] Region A1 is one head pitch downstream of region A2, and is an area where the carriage 3 has passed and printing has been completed. That is, in region A1, a pre-treatment layer Lpre, first to fourth ink layers LCA to LCD, and a post-treatment layer Lpos are formed over the entire length in the main scanning direction.

[0045] 5B shows the state in which, after completing the outward main scan in FIG. 5A, the carriage 3 turns around and moves in the return direction SB while performing the return main scan. Before the return movement, the workpiece W is sent out one head pitch in the transport direction F. Area A5 on the workpiece W is one head pitch upstream of area A4, and is the area that the pretreatment head 5 faces during this return main scan. A pretreatment layer Lpre is formed on area A5 by the pretreatment liquid ejected from the pretreatment head 5.

[0046] In region A4 and region A3, the first to fourth ink layers LCA to LCD and the post-treatment layer Lpos are respectively formed on existing layers. Specifically, in region A4, the first to fourth ink layers LCA to LCD are formed on the pre-treatment layer Lpre. In region A3, the post-treatment layer Lpos is formed on the first to fourth ink layers LCA to LCD. Region A2 is the region where printing processing has been completed following region A1.

[0047] The reason why printing is possible in both the forward main scan and the backward main scan as described above is because the pre-treatment head 5 and the post-treatment head 6 are shifted in the transport direction F relative to the ink head 4. If the pre-treatment head 5, ink head 4, and post-treatment head 6 were aligned in this order in the main scan direction S on the carriage 3, printing that ensures the pre-treatment liquid and post-treatment liquid land in the desired order could only be achieved in either the forward or backward main scan. To enable bidirectional printing, pairs of the pre-treatment head 5 and the post-treatment head 6 would have to be arranged on both sides of the ink head 4 array. In this case, the length of the carriage 3 in the main scan direction S would increase. This arrangement is unnecessary in this embodiment, so the length of the carriage 3 in the main scan direction S can be reduced.

[0048] If there are multiple rows of ink heads 4, it is possible to increase the amount of ink that lands on the workpiece W. For example, if there are two rows of ink heads 4, printing can be performed as follows. After the first row of ink heads 4 forms the first to fourth ink layers LCA to LCD as described above, the workpiece W is transported in the transport direction F by one head pitch, and the second row of ink heads 4 forms the first to fourth ink layers LCA to LCD. In this way, it is possible to print two layers' worth of ink on the workpiece W.

[0049] FIG. 6 is a plan view schematically illustrating the head arrangement on the carriage 3 according to this embodiment, and also illustrates the arrangement of the ink heads 4, pre-processing head 5, and post-processing head 6 (multiple processing heads) on the carriage 3 shown in FIG. 3. As described above, the carriage 3 is supported in a cantilevered manner by the guide rails 17 at the back frame 32 (engagement portion). The back frame 32 is disposed upstream of the head support frame 31 in the transport direction F. In the transport direction F, the side of the head support frame 31 on which the back frame 32 is disposed is referred to as the base end 311, and the side of the head support frame 31 opposite the base end 311 is referred to as the tip end 312. As described above, the head support frame 31 of the carriage 3 is equipped with first to sixth ink heads 4A to 4F, pre-processing head 5, and post-processing head 6, each of which ejects six different colors of ink. Each of the ink heads 4A to 4F of each color has two unit heads (12 in total). One pre-treatment head 5 and one post-treatment head 6 are provided.

[0050] The group of first to sixth ink heads 4A to 4F that make up the ink head 4 are arranged side by side in the main scanning direction S in the central region of the head support frame 31 in the transport direction F. The pre-processing head 5 is located near the right end of the carriage 3 in the main scanning direction S, upstream of the ink heads 4 in the transport direction F, at the base end 311 of the head support frame 31. Meanwhile, the post-processing head 6 is located at the right end of the carriage 3 in the main scanning direction S, downstream of the ink heads 4 in the transport direction F, at the tip end 312 of the head support frame 31.

[0051] The first ink head 4A includes an upstream ink head 4A1 and a downstream ink head 4A2 that is arranged downstream of the upstream ink head 4A1. That is, the upstream ink head 4A1 and the downstream ink head 4A2 are arranged in the transport direction F. The upstream ink head 4A1 is arranged closer to the base end side 311 in the central region of the head support frame 31. The downstream ink head 4A2 is arranged closer to the tip end side 312 in the central region of the head support frame 31. The downstream ink head 4A2 is arranged in a different position (shifted to the left) relative to the upstream ink head 4A1 in the main scanning direction S, where they partially overlap in the transport direction F. That is, in this embodiment, multiple ink heads of the same color are arranged in different positions from each other in the main scanning direction S, and so as to partially overlap each other in the transport direction F. When three or more ink heads of the same color are arranged in the transport direction F, two ink heads of the same color arranged adjacent to each other in the transport direction F are arranged as described above. Of course, the upstream ink head 4A1 and the downstream ink head 4A2 may also be arranged in the same position in the main scanning direction S (positions aligned linearly in the transport direction F). However, the arrangement in this embodiment allows for a smaller size of the carriage 3 in the transport direction F.

[0052] Furthermore, by arranging them in this manner, the ink heads 4 that eject one color are arranged together in the main scanning direction S. Specifically, all of the ink heads 4 that eject one color and are mounted on the carriage 3 are arranged so that no ink heads 4 that eject other colors are sandwiched between them in the main scanning direction S. Furthermore, all of the ink heads 4 that eject one color and are mounted on the carriage 3 may be arranged within a predetermined range, and no ink heads 4 that eject other colors may be arranged within that range.

[0053] If there is a difference in the printing condition, such as the landing position or ejection amount, between two ink heads 4, the difference is more likely to be noticeable when the two ink heads 4 eject the same color than when the two ink heads 4 eject different colors. If ink heads 4 that eject the same color are arranged together in the main scanning direction S, even if there is a difference in the printing condition between the ink heads 4, it is possible to make it less likely that the quality of the printed image will deteriorate.

[0054] The second to sixth ink heads 4B to 4F are similar to the upstream ink head 4A1 and downstream ink head 4A2 described above, and include upstream ink heads 4B1, 4C1, 4D1, 4E1, and 4F1 and downstream ink heads 4B2, 4C2, 4D2, 4E2, and 4F2. The upstream ink heads 4A1 to 4F1 of the first to sixth ink heads 4A to 4F are aligned in a row at the same position in the transport direction F and at a predetermined interval in the main scanning direction S. The downstream ink heads 4A2 to 4F2 are also aligned in a row at the same position in the transport direction F and at a predetermined interval in the main scanning direction S. As a result, a staggered arrangement is formed, with the downstream ink heads 4A2 to 4F2 partially interspersed between the arrangement pitches of the upstream ink heads 4A1 to 4F1.

[0055] The pre-treatment head 5 is positioned so that a portion of it is sandwiched between a pair of adjacent ink heads in the main scanning direction S. Specifically, the downstream portion of the pre-treatment head 5 is sandwiched between the upstream ink head 4E1 of the fifth ink head 4E and the upstream ink head 4F1 of the sixth ink head 4F. The pre-treatment head 5 is also positioned at the same position in the main scanning direction S as the downstream ink head 4F2 of the sixth ink head 4F.

[0056] The post-processing head 6 is positioned so that its upstream portion fits into the right-hand portion of the downstream ink head 4F2 of the sixth ink head 4F, and is positioned at the same position in the main scanning direction S as the upstream ink head 4F1. This positioning results in an overlapping area fa between the post-processing head 6 and the downstream ink head 4F2 in the transport direction F. In the transport direction F, the width of each head is greater than the printing width Pw and the width of the area in which the ejection nozzles are arranged. For this reason, each head is positioned with an overlapping area fa so that there is no gap between the printing range Pw of one row of heads and the printing range Pw of the heads in the adjacent row.

[0057] Unless otherwise specified, in each of the figures including Figure 6, the intervals between adjacent heads in the main scanning direction S (the intervals between the centers of the heads) are the same. Similarly, the intervals between adjacent heads in the transport direction F (the intervals between the centers of the heads) are the same.

[0058] As a result of the head arrangement described above, the pre-treatment head 5 and post-treatment head 6 are arranged within a range of arrangement width H in the main scanning direction S of the ink head 4. The ink head 4 has an arrangement width H in the main scanning direction S between the ink head 4A2 downstream of the first ink head 4A and the ink head 4F1 upstream of the sixth ink head 4F. The pre-treatment head 5 is arranged within the range of arrangement width H on the upstream side of the ink head 4, and the post-treatment head 6 is arranged within the range of arrangement width H on the downstream side of the ink head 4.

[0059] FIG. 7 is a plan view showing the schematic positional relationship of the nozzles of the ink heads and processing head shown in FIG. 6. In FIG. 7, the arrangement area of ​​the nozzles that are arranged on the underside of the head and that eject liquid during printing is shown inside the external shape of each head. The downstream ink heads (4A2 to 4F2) of the first ink head 4A to sixth ink head 4F are arranged in positions closest to the post-processing head 6 in the transport direction F among the ink heads of each color. Meanwhile, the upstream ink heads (4A1 to 4F1) of the first ink head 4A to sixth ink head 4F are arranged between the pre-processing head 5 and the downstream ink heads (4A2 to 4F2) in the transport direction F.

[0060] The upstream and downstream ends of the nozzle arrangement regions of the upstream ink heads (4A1 to 4F1) of the first ink head 4A to the sixth ink head 4F in the transport direction F are aligned with each other in the transport direction F. Similarly, the upstream and downstream ends of the nozzle arrangement regions of the downstream ink heads (4A2 to 4F2) of the first ink head 4A to the sixth ink head 4F in the transport direction F are aligned with each other in the transport direction F. Furthermore, the upstream end of the nozzle arrangement region of the upstream ink heads (4A1 to 4F1) in the transport direction F is contiguous to (in contact with or adjacent to) the downstream end of the nozzle arrangement region of the pre-treatment head 5 in the transport direction F. Furthermore, the upstream end of the nozzle arrangement region of the downstream ink heads (4A2 to 4F2) in the transport direction F is contiguous to the downstream end of the nozzle arrangement region of the upstream ink heads (4A1 to 4F1) in the transport direction F. Furthermore, the upstream end of the nozzle arrangement region of the post-treatment head 6 in the transport direction F is arranged contiguous to the downstream end of the nozzle arrangement region of the downstream ink heads (4A2 to 4F2) in the transport direction F.

[0061] In this way, the nozzles that eject the ink and each treatment liquid are arranged so that the ink and each treatment liquid land adjacent to each other in units of resolution. Therefore, the landing area of ​​the pre-treatment liquid and the landing area of ​​the ink of the upstream ink heads (4A1 to 4F1) are continuous (adjacent) at the pre-treatment / ink head boundary line L1, the landing area of ​​the ink of the upstream ink heads (4A1 to 4F1) are continuous at the ink head boundary line L2, and the landing area of ​​the ink of the downstream ink heads (4A2 to 4F2) are continuous at the ink / post-treatment head boundary line L3. This also applies to each of the following embodiments.

[0062] FIG. 8 is a block diagram of an inkjet printer 1 according to this embodiment. The inkjet printer 1 further includes a control unit 90 that controls the overall operation of each unit of the inkjet printer 1, a carriage driver 3S, an I / F 91, and an image memory 92. The control unit 90 is composed of a central processing unit (CPU), read-only memory (ROM) that stores control programs, random access memory (RAM) used as a work area for the CPU, and other components. The control unit 90 is electrically connected to the first motor M1, second motor M2, ink head 4, pre-processing head 5, and post-processing head 6, as well as the carriage driver 3S, I / F 91, and image memory 92. The carriage driver 3S includes a motor (not shown) that rotates a timing belt 16 to reciprocate the carriage 3 along the main scanning direction S.

[0063] The image memory 92 temporarily stores print image data provided from an external device such as a personal computer.

[0064] The I / F 91 is an interface circuit for realizing data communication with external devices, and for example creates communication signals that comply with the communication protocol of the network that connects the inkjet printer 1 to the external device, and converts communication signals from the network into data in a format that can be processed by the inkjet printer 1. A print instruction signal sent from a personal computer or the like is given to the control unit 90 via the I / F 91, and image data is stored in the image memory 92 via the I / F 91.

[0065] The control unit 90 functions as a drive control unit 901, a discharge control unit 902, a discharge pattern designation unit 903 (discharge head designation unit), and a storage unit 904 by the CPU executing a control program stored in the ROM.

[0066] The drive control unit 901 controls the first motor M1 and the second motor M2 of the work transport unit 20, thereby controlling the transport operation of the workpiece W. The drive control unit 901 also controls the carriage drive unit 3S, thereby controlling the reciprocating movement of the carriage 3 along the main scanning direction S.

[0067] The ejection control unit 902 inputs predetermined command signals to the ink head 4, the pre-treatment head 5, and the post-treatment head 6, and controls the ejection timing of the inks of each color, the pre-treatment liquid, and the post-treatment liquid.

[0068] The ejection pattern designation unit 903 designates the heads 4, 5, and 6 to perform ejection in accordance with the image information received from the I / F 91 or the image memory 92. More specifically, when there are multiple ejection patterns (e.g., multiple patterns stored in the storage unit 904) for the ratios of the ejection amounts of each liquid from the heads 4, 5, and 6 that can record an image in accordance with the image information, the ejection pattern designation unit 903 designates one of these ejection patterns to be used for recording. Specifically, when there are multiple heads 4, 5, and 6 that eject the same liquid, the ejection pattern is information that indicates how much liquid should be ejected from each of the heads 4, 5, and 6. The information on the ejection patterns is called ejection pattern information.

[0069] Next, we will explain how the ejection pattern designation unit 903 designates an ink ejection pattern. To land ink at a predetermined position on the workpiece W, the ejection ink heads that eject ink are designated from among multiple ink heads of the same color. More specifically, the ejection pattern designation unit 903 designates the ratio (ejection pattern) of the ejection amounts of the upstream ink heads (4A1-4F1) and downstream ink heads (4A2-4F2) among the ink heads 4 of each color, and inputs a signal corresponding to this ratio to the ejection control unit 902. FIG. 9 is a schematic plan view showing the upstream ink heads (4A1-4F1) and downstream ink heads (4A2-4F2) in an inkjet printer 1 according to this embodiment. FIG. 9 is an enlarged plan view of the upstream ink heads 4A1-4F1 and downstream ink heads 4A2-4F2 of the sixth ink head 4F that ejects black ink, among the ink heads 4 capable of ejecting multiple colors of ink, and the periphery of these ink heads. In the following explanation, as shown in FIG. 9, the upstream ink head may be referred to as H1 and the downstream ink head as H2, regardless of the ink color.

[0070] Regarding the upstream ink head H1 and the downstream ink head H2, the upstream ink head H1 is an ink head whose nozzle arrangement region is not connected to or overlaps with the nozzle arrangement region of the post-treatment head 6 when viewed along the main scanning direction S. On the other hand, the downstream ink head H2 is an ink head whose nozzle arrangement region is connected to or overlaps with the nozzle arrangement region of the post-treatment head 6 when viewed along the main scanning direction S. Note that, as will be described later, multiple upstream ink heads H1 may be arranged side by side in the transport direction F. In other words, each color ink head 4 may have three or more ink heads of the same color along the transport direction F.

[0071] The storage unit 904 stores in advance various thresholds, parameters, and the like referenced by the drive control unit 901, the discharge control unit 902, and the discharge pattern designation unit 903. When printing a specific pixel in an image formed on the workpiece W with a specific ink, the storage unit 904 also stores information (discharge pattern information) that combines the number of ink heads that can print the pixel at the requested density and the ink discharge amount of each ink head. The storage unit 904 has multiple pieces of discharge pattern information stored corresponding to at least one density. If there are multiple printable pixel densities, there may be densities for which multiple pieces of discharge pattern information are not stored correspondingly.

[0072] The plurality of ejection pattern information stored in advance corresponding to one density may include, for example, ejection pattern information for ejection from two (n) ink heads and ejection pattern information for ejection from one (n-1) or less ink head. In other words, the storage unit 904 stores in advance the information for ejecting ink from different numbers of ink heads when forming an image of a predetermined pixel at a predetermined density. In this embodiment, since two ink heads 4 are arranged for each ink color, two types of ejection patterns are stored as the information: an ink ejection pattern (first ejection pattern, first ejection pattern information) from the upstream ink head H1 and the downstream ink head H2, and an ink ejection pattern (second ejection pattern, second ejection pattern information) from only the upstream ink head H1. The ejection pattern designation unit 903 selectively references these pattern information.

[0073] As the first ejection pattern, multiple ejection patterns may be stored, each having a different ratio of the ink amount in the upstream ink head H1 to the ink amount in the downstream ink head H2. Also, multiple different drive signals that eject the same amount of liquid may exist as the drive signals that drive the ejection elements of the heads 4, 5, and 6. If information on the type of drive signal is also stored as the ejection pattern, multiple ejection patterns may be stored as both the first ejection pattern and the second ejection pattern.

[0074] Furthermore, the information may also include the ink ejection pattern (third ejection pattern, third ejection pattern information) for only the downstream ink head H2. As will be described later, by using the first ejection pattern or the second ejection pattern instead of the third ejection pattern, degradation of image quality can be prevented.

[0075] <Challenges in head placement> 18 is a plan view schematically illustrating the arrangement of ink heads and processing heads on a carriage in another inkjet recording device compared to the embodiments of the present disclosure. In this inkjet recording device, first ink head 4A to sixth ink head 4F, which eject ink of each color, are arranged in a line along the main scanning direction S. Furthermore, pre-treatment head 5 is adjacent to sixth ink head 4F in the main scanning direction S and is arranged upstream of sixth ink head 4F in the transport direction. Furthermore, post-treatment head 6 is adjacent to sixth ink head 4F in the main scanning direction S and is arranged downstream of sixth ink head 4F in the transport direction. Pre-treatment head 5 and post-treatment head 6 are arranged at the same position in the main scanning direction S. Note that in these ink heads and processing heads, the nozzles are arranged consecutively in the transport direction F, similar to FIG. 7. 18, when the ink head 4 and the post-treatment head 6 are arranged next to each other in the transport direction F, if printing is performed while the carriage 3 moves in a specific direction in the main scanning direction S (that is, in the case of bidirectional printing), the post-treatment liquid may directly affect the pre-treatment liquid at the boundary between the heads in the transport direction F, resulting in a decrease in the color density of the ink. This phenomenon is described in detail below.

[0076] Figures 19 and 20 are schematic diagrams illustrating the landing of ink and each treatment liquid on image dots near the head boundary in the inkjet recording device shown in Figure 18. In Figures 19 and 20, △ indicates pre-treatment liquid 5M ejected from pre-treatment head 5, ◯ indicates ink 4M ejected from ink head 4, and ◇ indicates post-treatment liquid 6M ejected from post-treatment head 6. Note that the liquids (4M, 5M, 6M) that are depicted overlapping in each figure actually land at the same point, and for the sake of explanation, they are depicted partially shifted in the main scanning direction S.

[0077] Part A of FIG. 19 (and also part A of FIG. 20) shows how a predetermined pixel boundary line L on the workpiece W is positioned at the boundary line LA between the pretreatment head 5 and ink head 4 in FIG. 18. Downstream of the pixel boundary line L in the transport direction F, the ink 4M lands on top of the pretreatment liquid 5M that has already landed. Meanwhile, upstream of the pixel boundary line L in the transport direction F, the pretreatment liquid 5M lands in conjunction with the movement of the carriage 3 in the main scanning direction S, at the same time as the ink 4M lands on the downstream side. In other words, this pixel boundary line L is a main scanning boundary line, which is the boundary between pixels where the timing of the landing of each liquid is different in the main scanning direction.

[0078] When the workpiece W is transported intermittently in the transport direction F from the state of part A in FIG. 19 , the pixel boundary line L described above is positioned at the boundary line LB between the ink head 4 and the post-treatment head 6 in FIG. 18 . Here, when the ink 4M and the post-treatment liquid 6M are ejected and land as the carriage 3 moves in the return direction SB ( FIG. 18 ), the post-treatment head 6 is positioned on the leading edge side of the ink head 4 in the return direction SB as shown in FIG. 18 . Therefore, as shown in part B in FIG. 19 , the post-treatment liquid 6M first lands downstream of the pixel boundary line L in the transport direction F. At this time, as shown by the arrow, due to landing deviation or bleeding of the post-treatment liquid 6M, some of it may flow upstream of the pixel boundary line L in the transport direction F. After that, as the carriage 3 moves in the same return direction SB, the ink 4M lands upstream of the pixel boundary line L in the transport direction F (part C in FIG. 19 ). At this time, the color density of the ink 4M decreases due to the influence of the post-treatment liquid 6M that has flowed in as described above (phenomenon 1: 4MA in part C in FIG. 19).

[0079] This decrease in color density is thought to manifest itself, for example, as follows: Normally, when the pretreatment liquid 5M and ink 4M mix, the pigment in ink 4M aggregates in an extremely short time. However, it takes some time for it to bind to the fibers of the workpiece W. Therefore, if the flow of liquid penetrating into the fibers of the workpiece W increases during the time between ink 4M landing and binding, the proportion of pigment drawn deep into the workpiece W increases, and less pigment remains near the surface of the workpiece W, resulting in a lighter apparent color. Note that the pretreatment liquid 5M lands in the scan preceding the ink 4M landing scan. Furthermore, because the penetration of the pretreatment liquid 5M is strongest immediately after landing, it is usually somewhat weakened by the time ink 4M lands. However, if the flow of penetration increases due to misalignment or bleeding of the posttreatment liquid 6M that lands next to ink 4M in the same scan, the color is likely to become lighter, as described above.

[0080] This phenomenon will be explained using FIG. 19. When the post-treatment liquid 6M bleeds or impact misalignment described above causes the post-treatment liquid 6M to act on the impact area of ​​the adjacent pre-treatment liquid 5M, a mixture of the pre-treatment liquid 5M and the post-treatment liquid 6M flows and penetrates deep into the workpiece W (fabric, paper). In particular, because the time interval between the transition from part B in FIG. 19 to part C in FIG. 19 during the same scan is short, the ink 4M in part C in FIG. 19 lands before the flow of this mixed liquid subsides. Therefore, the proportion of pigment in the impacting ink 4M that penetrates deep into the workpiece W increases, resulting in a faded color on the workpiece W. Furthermore, the post-treatment liquid 6M reduces the concentration of the pre-treatment liquid 5M, preventing the pigment in the ink 4M that impacts later from fully coagulating, resulting in a faded color. While this phenomenon is more pronounced when the ink contains a pigment, it can also occur when the ink contains a dye. Therefore, the term "dye" used here encompasses both pigment and dye.

[0081] In addition, in part C of Figure 19, if part of the ink 4M (4MA) that has landed upstream of the pixel boundary line L in the transport direction F flows downstream of the pixel boundary line L in the transport direction F as shown by the arrow, it may act on the post-treatment liquid 6M that has already landed, causing a slight change in image density (phenomenon 2).

[0082] On the other hand, after part A of Fig. 20 (which is the same as part A of Fig. 19), when the ink 4M and the post-treatment liquid 6M are ejected and land as the carriage 3 moves in the forward direction SA (Fig. 18), the ink head 4 is disposed on the leading edge side in the forward direction SA relative to the post-treatment head 6 as shown in Fig. 18, and therefore the ink 4M first lands upstream of the pixel boundary line L in the transport direction F, as shown in part B of Fig. 20 (note that the ink 4M downstream of the pixel boundary line L in the transport direction F in part B of Fig. 20 is the ink 4M that landed in the previous scan (part A of Fig. 20)). At this time, as shown by the arrow in part B of Fig. 20, misalignment or bleeding of the ink 4M may cause some of it to flow into the downstream part of the transport direction F of the pixel boundary line L (phenomenon 3).

[0083] 20, when the post-treatment liquid 6M lands downstream of the pixel boundary line L in the transport direction F, part of the post-treatment liquid 6M may flow upstream of the pixel boundary line L in the transport direction F due to landing deviation or bleeding (phenomenon 4). Note that in phenomena 2, 3, and 4 above, the post-treatment liquid 6M does not directly act on the pre-treatment liquid 5M as in phenomenon 1, and therefore the problem of change in image density is smaller than in phenomenon 1.

[0084] In order to solve the problems caused by the above-mentioned phenomenon, in this embodiment, the ink head 4, pre-processing head 5 and post-processing head 6 are suitably arranged on the carriage 3, and the control unit 90 suitably controls the ink ejection pattern from the ink head 4.

[0085] That is, in this embodiment, as shown in FIGS. 6 and 7, multiple rows of ink heads 4 are arranged in the transport direction F, and ink of the same color can be ejected in different scans of the carriage 3. In particular, the nozzle arrangement region of the upstream ink head 4 is arranged at an interval in the transport direction F with respect to the nozzle arrangement region of the post-treatment head 6, and ink 4M can be ejected onto the workpiece W in a scan prior to the scan in which post-treatment liquid 6M is ejected from the post-treatment head 6. Therefore, as shown in part B of FIG. 19, in a state in which ink 4M has not landed immediately upstream of the pixel boundary line L, post-treatment liquid 6M will not land immediately downstream of the pixel boundary line L, and a decrease in image density (4MA) in part C of FIG. 19 can be made less likely to occur. Note that the number of ink heads 4 is not limited to two rows, and three or more rows may be arranged.

[0086] 10 is a schematic diagram illustrating the impact of ink and each treatment liquid on an image dot (pixel) near the head boundary in the inkjet printer 1 according to this embodiment. In this embodiment, when recording a high-density pixel on the workpiece W, the ejection pattern designation unit 903 (FIG. 8) selects a pattern in which ink 4M is ejected by both the first and second rows of ink heads 4 (upstream ink head H1, downstream ink head H2) from the ejection patterns stored in the memory unit 904, and inputs this information to the ejection control unit 902.

[0087] As a result, in a situation corresponding to part B in Fig. 19, the ink 4M has already landed in the part upstream of the pixel boundary line L in the transport direction F during the previous scan, as shown in part A in Fig. 10, so it is less likely that the post-treatment liquid 6M will directly interact with the pre-treatment liquid 5M, reducing the possibility of a decrease in image density as described above. In this way, by arranging the ink heads 4 in two rows, it is possible to reduce the influence of the post-treatment liquid 6M even if there are high-density pixels that need to be printed with two ink heads.

[0088] Furthermore, when recording pixels on the workpiece W that are lighter in density than the aforementioned darker pixels, the ejection pattern designation unit 903 selects from the ejection patterns stored in the memory unit 904 either a pattern in which ink 4M is ejected by both the first and second rows of ink heads 4 (first ejection pattern), or a pattern in which ink 4M is ejected by only the first row of ink heads 4 (second ejection pattern), and inputs this information to the ejection control unit 902.

[0089] In either ejection pattern, the total amount of ink ejected onto light pixels is made less than the total amount of ink ejected onto dark pixels. For example, if the density of the light pixels is half that of the dark pixels, the total amount of ink ejected onto the light pixels is made approximately half of the total amount of ink ejected onto the dark pixels. In this case, with the first ejection pattern, the amount of ink ejected from the two ink heads 4 is, for example, made approximately half. With the second ejection pattern, the amount of ink ejected from the ink heads 4 is made approximately the same, and by halving the number of ejecting ink heads 4, the total amount of ink is made approximately half.

[0090] When the ink 4M is ejected by both the first and second rows of ink heads 4, the possibility of a decrease in image density can be reduced, as in the case of high density described above (part A in Fig. 10). Furthermore, even when the ink 4M is ejected only by the first row of ink heads 4, as shown in part B in Fig. 10, the ink 4M has already landed in the area upstream of the pixel boundary line L in the transport direction F during the previous scan, making it less likely that the post-treatment liquid 6M will directly interact with the pre-treatment liquid 5M, and similarly, the possibility of a decrease in image density can be reduced.

[0091] Although examples of dark pixels and light pixels have been described above, it is possible to perform either one of these, or both. If the ink 4M is ejected only from the ink heads 4 in the second row, there is a risk that the post-treatment liquid 6M may be misaligned or smeared, which may directly affect the pre-treatment liquid 5M, as shown in part C of Figure 10. Therefore, it is desirable to adopt the ejection pattern as described above for both.

[0092] When the ink 4M is ejected from both the first and second rows of ink heads 4, the nozzles of the second row of ink heads 4 are less likely to dry out compared to when the ink 4M is ejected from only the first row of ink heads 4. In this case, the amount of ink 4M ejected from each ink head 4 is halved, but as shown in part A of Fig. 10, by allowing the post-treatment liquid 6M to flow in while at least the ink 4M has landed on the pre-treatment liquid 5M, it is possible to prevent the pre-treatment liquid 5M and the post-treatment liquid 6M from directly interacting with each other.

[0093] As described above, in this embodiment, the ejection pattern designation unit 903 appropriately designates the ejection patterns of the two rows of ink heads 4 according to the difference in density (gradation expression) formed on the workpiece W, thereby preventing a decrease in image density around the pixel boundary line L and achieving stable gradation expression.

[0094] In addition, when the multiple ink heads of the same color have n ink heads of the same color (n is an integer of 2 or greater) arranged at different positions in the transport direction F, and the ejection pattern designation unit 903 ejects ink from n-1 or less ink heads of the same color based on predetermined image information, the ejection ink heads can be designated so that the upstream ink head H1 ejects ink and the downstream ink head H2 does not eject ink. In this case as well, it is possible to prevent a decrease in density near the pixel boundary line L.

[0095] In this case, the storage unit 904 preferably stores in advance a plurality of ejection pattern information pieces related to combinations of the number of ejection ink heads and the amount of ink ejected from each ejection ink head, which are referenced by the ejection pattern designation unit 903 to form an image on the workpiece W at a predetermined density. In particular, the ejection pattern information preferably includes at least ejection pattern information (first pattern information) for ejecting ink from n ink heads of the same color and ejection pattern information (second pattern information) for ejecting ink from n-1 or fewer ink heads of the same color. In this case, when designating the ejection ink heads based on the latter ejection pattern information, the ejection pattern designation unit 903 may designate the ejection ink heads so that ink is ejected from the upstream ink head H1 and not from the downstream ink head H2. As a result, when it is not necessary to eject ink from all ink heads of the same color, ink ejection from the downstream ink head H2 is preferentially prevented, thereby preventing a decrease in density near the pixel boundary line L.

[0096] The inkjet printer 1 according to this embodiment may print using only ink, only pretreatment liquid and ink, or only ink and posttreatment liquid. In such cases, the aforementioned density reduction does not occur, so an ink ejection pattern using only the downstream ink head H2 (third ejection pattern) may be used. The degree of impact of the aforementioned density reduction may vary depending on the combination of pretreatment liquid, ink, posttreatment liquid, and workpiece W, as well as environmental factors such as temperature and humidity. If the impact of the aforementioned density reduction is small, the third ejection pattern may be used, prioritizing improvements to other factors that affect image quality. Furthermore, depending on the degree of impact of the aforementioned density reduction, the third ejection pattern may be used for certain densities, and ejection patterns other than the third ejection pattern may be used for other densities.

[0097] The ejection pattern used by the ejection pattern designation unit 903 when printing a specific ink at a specific density may be one that can be set by the user, or may be one that the user can select from among the ejection patterns stored in the storage unit 904. For all densities used for printing, by using a mode that is set to either a pattern in which ink is ejected from the upstream ink head H1 and the downstream ink head H2 respectively (first ejection pattern), or a pattern in which ink is ejected from the upstream ink head H1 but not from the downstream ink head H2 (second ejection pattern), it is possible to perform printing that does not include the third ejection pattern.

[0098] The control unit 90 may be able to set a discharge mode in which discharge patterns corresponding to a plurality of densities used for printing are collectively set as a specific discharge pattern. Furthermore, the control unit 90 may have a discharge mode in which discharge patterns that do not include the third discharge pattern described above are set for all densities used for printing.

[0099] Figure 11 is a schematic diagram illustrating the landing of ink and each treatment liquid on image dots near the head boundary in the inkjet recording apparatus according to this embodiment. As mentioned above, of phenomena 1 to 4 described using Figures 18 to 20, phenomena 2, 3, and 4 are less likely to lead to a large change in image density compared to phenomenon 1, but phenomenon 4, indicated by the arrow in part C in Figure 20, may result in a slight decrease in image density, although it is less than phenomenon 1.

[0100] The inkjet printer 1 according to this embodiment can also reduce the decrease in image density due to phenomenon 4. As mentioned above, in the states shown in parts B and C of Figure 20, during a predetermined scan of the carriage 3, the ink 4M may land first, causing the adjacent post-treatment liquid 6M to land misaligned or bleed. Therefore, compared to when the post-treatment liquid 6M lands during the next scan, the time between the ink 4M landing and the post-treatment liquid 6M having an effect is significantly shorter, which could result in the aggregated pigment being washed away deep into the fibers of the workpiece W along with the post-treatment liquid 6M before it has a chance to bond significantly with the fibers, resulting in a low density.

[0101] On the other hand, in this embodiment, when printing high-density pixels, for example, the ink 4M from the upstream ink head H1 lands more than one scanning time before the post-treatment liquid 6M lands, as shown in part A of Fig. 11. Furthermore, because a predetermined time has passed since the ink 4M1 from the upstream ink head H1 mixed with the pre-treatment liquid 5M, even if the post-treatment liquid 6M shifts or bleeds at an early timing after the ink 4M2 from the downstream ink head H2 lands, the impact of this is small.

[0102] Furthermore, referring to part B of FIG. 11, in this embodiment, when printing low-density pixels, the ink 4M is ejected at least from the upstream ink head H1, and by the time the post-treatment liquid 6M lands, a sufficient amount of time has passed since the ink 4M was mixed with the pre-treatment liquid 5M, so even if the post-treatment liquid 6M is displaced or smeared, the impact is small.

[0103] In this way, in this embodiment, it is possible to make it difficult for a decrease in image density due to phenomenon 4 to occur. Note that phenomenon 3, indicated by the arrow in part B in Fig. 20, is caused by new ink 4M flowing into ink 4M that has already landed, and therefore is less likely to lead to a large change in density compared to the phenomenon in which the post-treatment liquid 6M acts on the pre-treatment liquid 5M as described above.

[0104] Furthermore, the head arrangement according to this embodiment makes it possible to increase the required amount of ink and treatment liquid ejected while miniaturizing the carriage 3. In other words, by arranging the pre-treatment head 5 and post-treatment head 6 in a different position from the ink head 4 in the transport direction F, it is possible to arrange ink heads 4A to 4F capable of ejecting the required amount of ink in the main scanning direction S, and to shorten the length of the carriage in the main scanning direction required to mount the heads 4 to 6 while enabling printing processing in both forward main scanning and backward main scanning.

[0105] In particular, the first to sixth ink heads 4A to 4F each include an upstream ink head H1 (4A1 to 4F1) and a downstream ink head H2 (4A2 to 4F2) arranged in the transport direction F (a direction intersecting the arrangement direction of the multiple processing heads). Therefore, even if the number of ink heads 4 is increased to increase the amount of ink ejected for each color or to achieve multi-color printing, it is difficult to increase the length of the carriage 3 in the main scanning direction.

[0106] Furthermore, the pre-processing head 5 and post-processing head 6 are arranged within the range of the arrangement width H in the main scanning direction S of the first to sixth ink heads 4A to 4F (FIG. 6). Therefore, even when the pre-processing head 5 and post-processing head 6 are mounted on the carriage 3 in addition to the ink heads 4, there is no need to extend the length of the carriage 3 in the main scanning direction. In other words, it is possible to prevent the length of the carriage 3 from becoming too large in the main scanning direction.

[0107] Furthermore, the pre-treatment head 5 and post-treatment head 6 are arranged so that some of them fit between the arrangement pitches of the first to sixth ink heads 4A to 4F. By using such a staggered arrangement, the ink heads 4 and treatment heads 5 and 6, which are arranged at different positions in the transport direction F, can be arranged at high density in the transport direction F. This makes it possible to reduce the length of the carriage 3 in the transport direction F.

[0108] Furthermore, in the head arrangement in this embodiment, one pre-treatment head 5 is arranged upstream of the ink head 4 in the transport direction F, and one post-treatment head 6 is arranged downstream. In other words, it is possible to provide an all-in-one inkjet printer 1 in which three types of heads, namely heads for ejecting pre-treatment liquid, ink, and post-treatment liquid, are mounted on a single carriage 3. Furthermore, because the pre-treatment head 5, ink head 4, and post-treatment head 6 are arranged sequentially in the transport direction F, the pre-treatment liquid, ink, and post-treatment liquid can be ejected in a desired landing order in both the forward main scan and the backward main scan.

[0109] In this embodiment, the post-processing head 6 is disposed outside the arrangement range HB in the main scanning direction S within which the downstream ink heads H2 (4A2 to 4F2) of each color are disposed (FIG. 6). This arrangement allows the number of downstream ink heads H2 close to the post-processing head 6 in the main scanning direction S to be reduced. It also makes it possible to reduce the average distance in the main scanning direction S between the post-processing head 6 and the downstream ink heads H2 of each color. This reduces the occurrence of the phenomena described with reference to FIGS. 18 to 20. When multiple post-processing heads 6 are disposed, it is desirable that all of the post-processing heads 6 be disposed outside the arrangement range HB, as described below. However, at least some of the post-processing heads 6 may be disposed outside the arrangement range.

[0110] Furthermore, in this embodiment, the post-treatment head 6 is arranged so that it partially overlaps in the transport direction F with the multiple downstream ink heads 2H included in the multiple sets of same-color ink heads, and is arranged at the same position in the main scanning direction S as one upstream ink head (4F1 in FIG. 9) of the multiple upstream ink heads included in the multiple sets of same-color ink heads. With this configuration, the size of the carriage 3 on which the ink heads 4, pre-treatment head 5, and post-treatment head 6 are mounted can be made compact in both the main scanning direction S and the transport direction F.

[0111] Furthermore, in this embodiment, the carriage 3 has a back frame 32 (engagement portion) that is held in a cantilevered state by a guide rail 17 (holding member). By supporting the carriage 3 in a cantilevered manner on the timing belt 16, the structure can be simplified. Also, by supporting the carriage 3 in a cantilevered manner, the downstream side of the carriage 3 can be easily opened, making it easier to perform maintenance on the ink head 4 and the processing heads 5 and 6.

[0112] In this cantilever-supported carriage 3, the pre-processing head 5 is disposed on the base end 311 (the side closer to the engagement portion) of the head support frame 31, and the post-processing head 6 is disposed on the tip end 312 (the side farther from the engagement portion). Unlike the base end 311, which is closer to the back frame 32 fixed to the timing belt 16, it is expected that the positional accuracy will decrease at the free end, the tip end 312. However, the tip end 312 is equipped with the post-processing head 6, which does not require a relatively high level of ejection accuracy. Because the post-processing liquid coats the ink image printed on the workpiece W, even if a misalignment in the landing position occurs, the relative impact on image quality is smaller than if a similar misalignment in the landing position occurs with the pre-processing liquid. Therefore, even when a cantilever-supported carriage 3 is used, degradation of image quality is less likely to occur. Furthermore, even if a misalignment in the landing position of the post-processing liquid occurs, a decrease in image density near the pixel boundary line L can be reliably prevented, as described above.

[0113] 6, 7, and 9, the second row of downstream ink heads H2 for each color may not be arranged. In other words, in this case, there may be only one row of ink heads 4. However, in this case, it is desirable that the post-treatment head 6 is arranged in the transport direction F at a distance downstream from the first row of upstream ink heads H1, as shown in the above figures. That is, it is desirable that the nozzle arrangement region from which the ink heads 4 eject the ink 4M is arranged upstream in the transport direction F and away from the nozzle arrangement region from which the post-treatment liquid 6M is ejected from the post-treatment head 6. Note that, assuming this positional relationship, multiple rows of upstream ink heads H1 may be arranged. With this head arrangement, the landing position of the post-treatment liquid 6M will not be adjacent to the landing position of the ink 4M in the transport direction F, as shown in part B of FIG.

[0114] In this case, the inkjet printer 1 includes a work transport unit 20 that transports the workpiece W in a predetermined transport direction F, a carriage 3 that moves back and forth in a main scanning direction S that intersects with the transport direction F, ink heads 4 that are mounted on the carriage 3 and eject inks, at least one pre-treatment head 5 that is arranged upstream of the ink heads 4 in the transport direction F and ejects a non-color-forming pre-treatment liquid, and at least one post-treatment head 6 that is arranged downstream of the multiple ink heads 4 in the transport direction F and ejects a non-color-forming post-treatment liquid. The nozzle arrangement region of the ink head 4 is arranged at an interval in the transport direction F from the nozzle arrangement region of the post-treatment head 6 that is located downstream thereof.

[0115] Next, a description will be given of the head arrangement in the carriage 3 of an inkjet printer 1 according to another embodiment of the present disclosure. Note that in the following embodiments, differences from the first embodiment will be mainly described, and a description of commonalities will be omitted.

[0116] FIG. 12 is a schematic plan view showing an upstream ink head H1 and a downstream ink head H2 on a carriage 3A of an inkjet printer 1 (inkjet recording device) according to a second embodiment of the present disclosure. In the first embodiment, as shown in FIG. 9, the ink heads 4 for each color are provided in a single upstream ink head H1 and a single downstream ink head H2. In this embodiment, as shown in FIG. 12, the upstream ink head H1 includes two rows of heads (4F1, 4F2) arranged at different positions in the transport direction F, and the downstream ink head H2 includes a single row of heads (4F3), similar to the first embodiment. While FIG. 12 shows only the sixth black ink head 4F, the same applies to the ink heads of the other colors. In this embodiment, the heads are also arranged in a staggered pattern.

[0117] In this embodiment, the nozzle arrangement region of the downstream ink head H2 (4F3) is continuous (connected or adjacent) with the nozzle arrangement region of the post-processing head 6 along the transport direction F. On the other hand, the nozzle arrangement region of the upstream ink head H1 (4F1, 4F2) is spaced apart in the transport direction F from the nozzle arrangement region of the post-processing head 6. Therefore, in this embodiment as well, by ejecting ink from at least the upstream ink head H1 onto a predetermined pixel, a decrease in image density near the pixel boundary line L can be made less likely to occur.

[0118] In this case, the ejection pattern designation unit 903 employs a pattern in which ink is dispersed and ejected from three heads, the upstream ink head H1 and the downstream ink head H2, for the image density required for the predetermined pixel. As a result, as in part A of FIG. 10 and part B of FIG. 10, when at least the post-treatment liquid 6M ejected from the post-treatment head 6 lands at the predetermined pixel position, the ink 4M has already landed on the pre-treatment liquid 5M, making it difficult for the post-treatment liquid 6M to directly act on the pre-treatment liquid 5M.

[0119] Furthermore, when distributing ink from two heads to achieve the image density required for the predetermined pixel, the ejection pattern designation unit 903 may eject ink from two upstream ink heads H1. Furthermore, when n (n is an integer greater than or equal to 3) ink heads of the same color are arranged at different positions in the transport direction F for each color, and the ejection pattern designation unit 903 ejects ink from n-2 or fewer ink heads of the same color based on predetermined image information, the ejection ink head may be designated by giving priority to the ink head of the same color located upstream in the transport direction F among the multiple upstream ink heads H1. With this configuration, ink is ejected from the ink head that is more upstream, so that the post-treatment liquid 6M lands after the pre-treatment liquid 5M and the ink 4M have sufficiently reacted with each other. As a result, it becomes even more unlikely that the post-treatment liquid 6M will directly react with the pre-treatment liquid 5M.

[0120] Also in this embodiment, the storage unit 904 may store one or more pieces of ejection pattern information, which is information referenced by the ejection pattern designation unit 903 to form an image on the workpiece W at a predetermined density, and which relates to a combination of the number of ejection ink heads and the amount of ink ejected from each ejection ink head. If the ejection pattern information includes multiple pieces of ejection pattern information (specific ejection pattern information) stored in correspondence with at least one density and each having a different number of ejection ink heads, the ejection pattern designation unit 903 may select the ejection pattern information with the smallest number of ejection ink heads and designate the ejection ink head when recording an image at a density corresponding to and stored in correspondence with the multiple specific ejection pattern information. In this case, too, by preferentially ejecting ink from ink heads arranged upstream in the transport direction F using as few ink heads as possible, it becomes even more unlikely that the post-treatment liquid 6M will directly act on the pre-treatment liquid 5M.

[0121] Figure 13 is a plan view that schematically shows the arrangement of ink heads and treatment heads on a carriage 3B in an inkjet printer 1 according to a third embodiment of the present disclosure. In the first embodiment described above, the pre-treatment head 5 and post-treatment head 6 are respectively arranged at the right end of the ink head 4, but as shown in Figure 13, the pre-treatment head 5 and post-treatment head 6 may also be arranged at the left end of the ink head 4. In this case as well, by ejecting ink from at least the upstream ink head (for example, 4A1) of the ink heads 4, it becomes less likely that the post-treatment liquid 6M will directly interact with the pre-treatment liquid 5M in the vicinity of the pixel boundary line L.

[0122] FIG. 14 is a plan view schematically illustrating the arrangement of ink heads and processing heads on a carriage 3C in an inkjet printer 1 according to a fourth embodiment of the present disclosure. In the first embodiment, the upstream ink head H1 for each color was arranged to the right of the downstream ink head H2. However, as shown in FIG. 14, the upstream ink head may be arranged to the left of the downstream ink head. In this case, the ink heads 4, pre-processing head 5, and post-processing head 6 are arranged in a staggered pattern, allowing for a compact head arrangement area on the carriage 3. In both the embodiments shown in FIGS. 13 and 14, as in the first embodiment, the heads are arranged in a staggered pattern, and the pre-processing head 5 and post-processing head 6 are arranged within the arrangement range of the ink heads 4 in the main scanning direction S. This allows for a more compact size of the carriage 3 in the main scanning direction S and the transport direction F.

[0123] FIG. 15 is a plan view schematically illustrating the arrangement of ink heads and processing heads on a carriage 3D in an inkjet printer 1 according to a fifth embodiment of the present disclosure. While the first embodiment described an arrangement in which one pre-processing head 5 and one post-processing head 6 are arranged, as shown in FIG. 15 , an alternative embodiment may include two post-processing heads 6A and 6B arranged at different positions in the main scanning direction S. In this case, the post-processing heads 6A and 6B are arranged side by side in the main scanning direction S, outside the arrangement range HB in which the downstream ink heads H2 of each color are arranged in the main scanning direction S. This arrangement reduces the number of downstream ink heads H2 close to the post-processing heads 6A and 6B in the main scanning direction S. It also reduces the average distance in the main scanning direction S between the post-processing heads 6A and 6B and the downstream ink heads H2 of each color. As a result, the occurrence of the phenomena described with reference to FIGS. 18 to 20 can be reduced. Furthermore, as in this embodiment, by configuring the post-processing head 6 with multiple post-processing heads 6A, 6B, even if the amount of post-processing liquid ejected by a single head is insufficient, the required amount can be ejected by arranging multiple post-processing heads 6A, 6B. Note that the number of post-processing heads in Figure 15 may be three or more.

[0124] FIG. 16 is a plan view that schematically shows the arrangement of ink heads and processing heads on a carriage 3E in an ink jet printer 1 according to a sixth embodiment of the present disclosure.

[0125] In this embodiment as well, the carriage 3E is held in a cantilevered state by a back frame 32 (engagement portion) on guide rails 17 (holding members) (FIGS. 1 and 2). The head support frame 31 is mounted with ink heads 4 each having first to sixth ink heads 4A to 4F, one pre-treatment head 5, and a post-treatment head 6 having two post-treatment heads 6A and 6B. In this embodiment as well, by ejecting ink from at least the ink head 4 on the upstream side in the transport direction F toward the predetermined pixel, the post-treatment liquid 6M acts directly on the pre-treatment liquid 5M in the vicinity of the pixel boundary line L, making it less likely that a decrease in image density will occur.

[0126] This embodiment also includes post-processing heads 6A and 6B that are positioned at different positions in the main scanning direction S. As shown in FIG. 16 , post-processing head 6B is positioned outside the arrangement range HB of the downstream ink heads H2 included in the multiple sets of same-color ink heads in the main scanning direction S (first post-processing head). Meanwhile, post-processing head 6A is positioned so that a portion of it is inserted between a pair of adjacent downstream ink heads H2 in the main scanning direction S, among the multiple downstream ink heads H2, and is positioned alongside post-processing head 6B in the main scanning direction S (second post-processing head). This arrangement also reduces the number of ink heads close to the post-processing heads 6A and 6B in the main scanning direction S. It also reduces the average distance in the main scanning direction S between post-processing heads 6A and 6B and the downstream ink heads of each color. While achieving these effects, the size of the carriage 3 in the main scanning direction S can be made compact.

[0127] In this embodiment, the pre-processing head 5 is made up of one unit head, and the post-processing head 6 is made up of two unit heads (post-processing heads 6A and 6B). Of these pre-processing heads 5 and post-processing heads 6, the pre-processing head 5, which has the fewest number of unit heads, is arranged on the base end side 311 of the head support frame 31. The post-processing head 6, which has the most unit heads, is arranged on the tip end side 312. In other words, the upstream edge of the head support frame 31 in the transport direction F is the side that is held by the guide rail 17.

[0128] As described above, the processing heads 5 and 6 generate heat during the ejection operation. As shown schematically in FIG. 16, the pre-processing head 5, which has reached a high temperature, dissipates heat ha. The same is true for the post-processing heads 6A and 6B. This heat ha warms the head support frame 31 of the carriage 3E, which can cause thermal deformation of the head support frame 31 and its supporting structure, the back frame 32, and the metal fittings connecting the back frame 32 to the timing belt 16. This thermal deformation can affect the landing accuracy of ink ejected from the ink head 4 when the carriage 3E is held in a cantilevered state.

[0129] However, in the carriage 3E according to this embodiment, the pre-processing head 5, which has a smaller number of unit heads, is arranged on the base end side 311, which is the side that is cantilevered by the head support frame 31. This makes it possible to reduce the effects of thermal deformation (deterioration of landing accuracy). If the post-processing head 6, which has a larger number of unit heads, were arranged on the base end side 311, the back frame 32 would receive heat ha from the two unit heads, become even hotter, and be more susceptible to thermal deformation.

[0130] Furthermore, in the carriage 3E, the pre-processing head 5, which is arranged closest to the back frame 32 of the carriage 3E, is arranged at a position excluding the end in the main scanning direction S of the array HA of the ink heads 4 and processing heads 5, 6. Of the heads 4, 5, 6 mounted on the carriage 3E, the pre-processing head 5 is the head arranged closest to the back frame 32 (engagement portion). Such a pre-processing head 5 is arranged at a position excluding the arrangement end 313, which is the end of the head array HA.

[0131] Because the carriage 3E cannot be made unnecessarily large, if a head were to be placed at the arrangement edge 313 of the head array in the main scanning direction S, that head would be closest to the corner of the carriage 3E (head support frame 31) in the main scanning direction S. Because the arrangement edge 313 is also near the cantilevered back frame 32, thermal deformation in that vicinity can induce distortion or misalignment of the head support frame 31 in the vertical and horizontal directions. This reduces the landing position accuracy of the heads 4, 5, and 6 mounted on the carriage 3E. Therefore, by not placing the pre-processing head 5, which becomes hot, in the area of ​​the arrangement edge 313, the above-mentioned thermal deformation problem can be made less likely to occur.

[0132] Also in this embodiment, of the two rows of ink heads 4, the row of heads 4 located on the engagement portion side (upstream ink heads H1) is arranged in a staggered position shifted to the right in Figure 16. Furthermore, the pre-processing head 5, which is the processing head with the fewest heads, is arranged on the engagement portion side, and is arranged at the rightmost position of the staggered arrangement. By arranging the heads in this manner, it is possible to arrange the heads so that the processing heads are not located at the arrangement end 313.

[0133] Furthermore, in this embodiment, compared to the similar arrangement in Figure 15 in which multiple post-processing heads 6 are arranged, the post-processing heads 6A and 6B are arranged within the arrangement range of the ink head 4 in the main scanning direction S, so the size of the carriage 3E can be made compact.

[0134] 17 is a plan view showing the schematic arrangement of the ink heads, processing heads, and sub-tanks on the carriage 3E in the inkjet printer 1 according to this embodiment. The following provides an example of a preferred arrangement of the heads 4, 5, and 6 on the carriage 3E and the sub-tanks that supply ink or processing liquid to them.

[0135] The carriage 3E is also equipped with subtanks 7. The subtanks 7 include ink subtanks 7A to 7F, a pre-treatment liquid subtank 71, and a post-treatment liquid subtank 72. These subtanks 7 are supplied with ink, pre-treatment liquid, and post-treatment liquid, respectively, from a main tank (not shown). The ink subtanks 7A to 7F supply the ink to the first to sixth ink heads 4A to 4F, respectively. For example, the first color ink is supplied to the upstream ink head 4A1 of the first ink head 4A from the first tank 7A1 of the ink subtank 7A, and the downstream ink head 4A2 is supplied with ink from the second tank 7A2 via a pipe P1. Similarly, the second to sixth colors of ink are supplied to the second to sixth ink heads 4B to 4F, respectively. The arrangement order of the ink subtanks 7 in the main scanning direction S is the same as the arrangement order of the ink heads 4 to which the ink subtanks 7 supply ink.

[0136] Note that ink may be supplied from a single ink subtank 7 to multiple ink heads 4 that eject ink of the same color. In this case, the ink heads 4 that share the ink subtank 7 may be arranged close together in the main scanning direction S. Furthermore, it is preferable to arrange the ink heads 4 that eject the same ink close together in the main scanning direction S, and the order in which the ink subtanks 7 of each color are arranged in the main scanning direction S may be the same as the order in which the ink heads 4 of each color are arranged.

[0137] The pre-processing liquid sub-tank 71 supplies the pre-processing liquid to the pre-processing head 5 via a pipe P2. The post-processing liquid sub-tank 72 includes a first tank 72A and a second tank 72B. The first and second tanks 72A and 72B supply the post-processing liquid to the post-processing heads 6A and 6B, respectively, via a pipe P3.

[0138] The ink subtanks 7A to 7F are mounted on the carriage 3E so as to be aligned in the main scanning direction S. The treatment liquid subtanks 71 and 72 are arranged aligned in the main scanning direction S at positions different from the ink subtanks 7A to 7F in the transport direction F. Specifically, the pre-treatment liquid subtank 71 and the first and second tanks 72A and 72B of the post-treatment liquid subtank 72 are aligned in a row in the main scanning direction S downstream of the ink subtanks 7A to 7F in the transport direction F. Note that only the pre-treatment liquid subtank 71 may be arranged upstream of the ink subtanks 7A to 7F.

[0139] The liquid in the sub-tank 7, which is mounted on the carriage 3E that moves back and forth in the main scanning direction S, is subjected to acceleration in the main scanning direction S. The sub-tank 7 and each of the heads 4, 5, and 6 are connected by conduits P1, P2, and P3, but if the sub-tanks 7 are widely distributed on the carriage 3J, the arrangement range of the conduits P1 to P3 in the main scanning direction S also becomes large. Because these conduits P1 to P3 are also filled with ink or treatment liquid, the influence of the acceleration can cause meniscus destruction in the ejection portions of the heads 4, 5, and 6.

[0140] However, according to the configuration of this embodiment, the ink sub-tanks 7A to 7F are mounted on the carriage 3E so as to be aligned in the main scanning direction S, just like the first to sixth ink heads 4A to 4F. This makes it possible to arrange the ink sub-tanks 7A to 7F in a relatively narrow area on the head support frame 31 of the carriage 3J. Similarly, the pre-treatment liquid sub-tank 71 and the post-treatment liquid sub-tank 72 can also be arranged in a relatively narrow area on the head support frame 31 of the carriage 3E.

[0141] Furthermore, because the pre-treatment liquid sub-tank 71 and the post-treatment liquid sub-tank 72 are disposed at positions separate from the ink sub-tanks 7A to 7F in the transport direction F, the difference in position in the main scanning direction S between the pre-treatment liquid sub-tank 71 and the post-treatment liquid sub-tank 72 and the processing heads to which the pre-treatment liquid sub-tank 71 and the post-treatment liquid sub-tank 72 supply processing liquid can be reduced. This reduces the distribution range in the main scanning direction S of the pre-treatment liquid that is connected to the pre-treatment liquid sub-tank 71, the conduit P, and the pre-processing head 5, making it less susceptible to the effects of the acceleration. Similarly, the distribution range in the main scanning direction S of the connected post-processing liquid can be reduced, making it less susceptible to the effects of the acceleration.

[0142] Similarly, the ink subtanks 7A to 7F and the ink heads 4 to which the ink subtanks 7A to 7F supply ink can be positioned with little difference in position in the main scanning direction S. This reduces the distribution range of connected ink in the main scanning direction S, making it less susceptible to the effects of the acceleration.

[0143] Next, the head arrangement on the carriage in another inkjet recording device compared to the inkjet printer 1 according to each embodiment of the present disclosure will be described. Figure 21 is a plan view that schematically shows the arrangement of the ink heads and processing heads on the carriage in the other inkjet recording device.

[0144] 18 to 20 become more pronounced when the pre-treatment liquid 5M, the ink 4M, and the post-treatment liquid 6M are caused to land on predetermined pixels on the workpiece W by different scans (movement of the carriage 3). The head arrangements according to the above-described embodiments can suitably solve such problems.

[0145] On the other hand, in the example shown in FIG. 21 , two pre-treatment heads 5A and 5B are arranged on either side of the multiple ink heads 4 (4A to 4F) in the main scanning direction S, and a post-treatment head 6 is arranged downstream of these heads in the transport direction F. In this case, during a scan of the carriage 3 in a predetermined direction, the pre-treatment liquid 5M can be ejected and landed from the pre-treatment head 5A or 5B, and the ink 4M can be ejected and landed from each ink head 4. Then, during the next scan of the carriage 3, the post-treatment liquid 6M can be ejected and landed from the post-treatment head 6. In this case, because the ink 4M lands while the pre-treatment liquid 5M is penetrating into the fibers of the workpiece W, even if misalignment or bleeding occurs when the post-treatment liquid 6M lands thereafter, the pigment of the ink 4M is less likely to penetrate deep into the fibers than when the ink 4M lands after the penetration of the pre-treatment liquid 5M has stopped. However, even in the example shown in Fig. 21, when bidirectional printing is performed, the time interval between the landing of the ink 4M and the landing of the post-treatment liquid 6M is short at the end of the main scanning direction S where the movement direction of the carriage 3 switches, which raises concerns about the aforementioned decrease in image density, but because the ink 4M and the pre-treatment liquid 5M already land at an even shorter time interval within the same scan as described above, a decrease in image density due to direct interaction between the pre-treatment liquid 5M and the post-treatment liquid 6M is unlikely to occur. In other words, with the arrangement shown in Fig. 21, the issue of pixel density decrease described using Fig. 19 does not substantially occur. [Explanation of symbols]

[0146] 1. Inkjet printer (ink head recording device) 16 Timing belt (moving part) 17 Guide rail (holding member) 20 Work transport unit (transport unit) 3, 3A~3E Carriage 31 Head support frame 32 Back Frame 4 ink heads 4A~4F 1st~6th ink heads 5 Pre-processing head (processing head) 6 Post-processing head (processing head) 7 Subtank 71 Sub-tank for pre-treatment liquid 72 Sub-tank for post-processing liquid 7A~7F Ink subtank 90 Control Unit 901 Drive control unit 902 Discharge control section 903 Discharge pattern designation section (discharge head designation section) 904 Storage section F Conveying direction H1 Upstream ink head H2 downstream ink head S Main scanning direction W work (recording media)

Claims

1. a conveying unit that conveys the recording medium in a predetermined conveying direction; a carriage that moves back and forth in a main scanning direction that intersects with the transport direction; At least one head is disposed on the carriage and has a nozzle arrangement area formed on a lower surface thereof for ejecting liquid; Equipped with The lower surface of the at least one head has: a plurality of ink nozzle arrangement areas, each of which is a nozzle arrangement area that ejects ink; at least one pretreatment nozzle arrangement area that is arranged upstream of the plurality of ink nozzle arrangement areas in the transport direction and that is a nozzle arrangement area that ejects a non-color-forming pretreatment liquid; at least one post-treatment nozzle arrangement area that is arranged downstream of the plurality of ink nozzle arrangement areas in the transport direction and that is a nozzle arrangement area that ejects a non-color-forming post-treatment liquid; is formed, the plurality of ink nozzle arrangement areas include a plurality of same-color ink nozzle arrangement areas that are arranged side by side in the transport direction and eject ink of the same color, The inkjet recording apparatus is configured such that the plurality of same-color ink nozzle arrangement regions are at different positions in the main scanning direction and are arranged so as to partially overlap one another in the transport direction.

2. A conveying unit that conveys a recording medium in a predetermined conveying direction; a carriage that moves back and forth in a main scanning direction that intersects with the transport direction; At least one head is disposed on the carriage and has a nozzle arrangement area formed on a lower surface thereof for ejecting liquid; Equipped with The lower surface of the at least one head has: a plurality of ink nozzle arrangement areas, each of which is a nozzle arrangement area that ejects ink; at least one pretreatment nozzle arrangement area that is arranged upstream of the plurality of ink nozzle arrangement areas in the transport direction and that is a nozzle arrangement area that ejects a non-color-forming pretreatment liquid; at least one post-treatment nozzle arrangement area that is arranged downstream of the plurality of ink nozzle arrangement areas in the transport direction and that is a nozzle arrangement area that ejects a non-color-forming post-treatment liquid; is formed, the plurality of ink nozzle arrangement areas include a plurality of same-color ink nozzle arrangement areas that are arranged side by side in the transport direction and eject ink of the same color, the plurality of ink nozzle arrangement areas include a plurality of sets of same-color ink nozzle arrangement areas that are arranged side by side in the main scanning direction and each ejects ink of a different color, when the plurality of same-color ink nozzle arrangement areas are considered as a set of same-color ink nozzle arrangement areas, The plurality of sets of same-color ink nozzle arrangement regions are a downstream ink nozzle arrangement area that is arranged at a position closest to the post-processing nozzle arrangement area in the transport direction; at least one upstream ink nozzle arrangement region disposed between the pretreatment nozzle arrangement region and the downstream ink nozzle arrangement region in the transport direction; Each of these includes an inkjet recording apparatus, wherein the at least one post-processing nozzle arrangement region is arranged outside, in the main scanning direction, an arrangement range of the plurality of downstream ink nozzle arrangement regions included in the plurality of sets of same-color ink nozzle arrangement regions;

3. 3. The inkjet recording apparatus according to claim 2, the at least one post-processing nozzle arrangement region includes a plurality of post-processing nozzle arrangement regions that are arranged at different positions in the main scanning direction, an inkjet recording apparatus, wherein the plurality of post-processing nozzle arrangement regions are arranged side by side outside of an arrangement range of the plurality of downstream ink nozzle arrangement regions in the main scanning direction;

4. A conveying unit that conveys the recording medium in a predetermined conveying direction; a carriage that moves back and forth in a main scanning direction that intersects with the transport direction; At least one head is disposed on the carriage and has a nozzle arrangement area formed on a lower surface thereof for ejecting liquid; Equipped with The lower surface of the at least one head has: a plurality of ink nozzle arrangement areas, each of which is a nozzle arrangement area that ejects ink; at least one pretreatment nozzle arrangement area that is arranged upstream of the plurality of ink nozzle arrangement areas in the transport direction and that is a nozzle arrangement area that ejects a non-color-forming pretreatment liquid; at least one post-treatment nozzle arrangement area that is arranged downstream of the plurality of ink nozzle arrangement areas in the transport direction and that is a nozzle arrangement area that ejects a non-color-forming post-treatment liquid; is formed, the plurality of ink nozzle arrangement areas include a plurality of same-color ink nozzle arrangement areas that are arranged side by side in the transport direction and eject ink of the same color, the plurality of ink nozzle arrangement areas include a plurality of sets of same-color ink nozzle arrangement areas that are arranged side by side in the main scanning direction and each ejects ink of a different color, when the plurality of same-color ink nozzle arrangement areas are considered as a set of same-color ink nozzle arrangement areas, The plurality of sets of same-color ink nozzle arrangement regions are a downstream ink nozzle arrangement area that is arranged at a position closest to the post-processing nozzle arrangement area in the transport direction; at least one upstream ink nozzle arrangement region disposed between the pretreatment nozzle arrangement region and the downstream ink nozzle arrangement region in the transport direction; Each of these includes an inkjet recording device, wherein the at least one post-processing nozzle arrangement region is arranged so that a portion of the at least one post-processing nozzle arrangement region overlaps with a plurality of downstream ink nozzle arrangement regions included in the plurality of sets of same-color ink nozzle arrangement regions in the transport direction, and is arranged at the same position in the main scanning direction as one upstream ink nozzle arrangement region among the plurality of upstream ink nozzle arrangement regions included in the plurality of sets of same-color ink nozzle arrangement regions.

5. A conveying unit that conveys the recording medium in a predetermined conveying direction; a carriage that moves back and forth in a main scanning direction that intersects with the transport direction; At least one head is disposed on the carriage and has a nozzle arrangement area formed on a lower surface thereof for ejecting liquid; Equipped with The lower surface of the at least one head has: a plurality of ink nozzle arrangement areas, each of which is a nozzle arrangement area that ejects ink; at least one pretreatment nozzle arrangement area that is arranged upstream of the plurality of ink nozzle arrangement areas in the transport direction and that is a nozzle arrangement area that ejects a non-color-forming pretreatment liquid; at least one post-treatment nozzle arrangement area that is arranged downstream of the plurality of ink nozzle arrangement areas in the transport direction and that is a nozzle arrangement area that ejects a non-color-forming post-treatment liquid; is formed, the plurality of ink nozzle arrangement areas include a plurality of same-color ink nozzle arrangement areas that are arranged side by side in the transport direction and eject ink of the same color, the plurality of ink nozzle arrangement areas include a plurality of sets of same-color ink nozzle arrangement areas that are arranged side by side in the main scanning direction and each ejects ink of a different color, when the plurality of same-color ink nozzle arrangement areas are considered as a set of same-color ink nozzle arrangement areas, The plurality of sets of same-color ink nozzle arrangement regions are a downstream ink nozzle arrangement area that is arranged at a position closest to the post-processing nozzle arrangement area in the transport direction; at least one upstream ink nozzle arrangement region disposed between the pretreatment nozzle arrangement region and the downstream ink nozzle arrangement region in the transport direction; Each of these includes the at least one post-processing nozzle arrangement region includes a plurality of post-processing nozzle arrangement regions that are arranged at different positions in the main scanning direction, The plurality of post-processing nozzle arrangement areas include: a first post-processing nozzle arrangement area that is arranged outside in the main scanning direction with respect to an arrangement range of the plurality of downstream ink nozzle arrangement areas included in the plurality of sets of same-color ink nozzle arrangement areas; at least one second post-processing nozzle arrangement region that is arranged such that a portion of the second post-processing nozzle arrangement region is interposed between a pair of downstream ink nozzle arrangement regions that are adjacent to each other in the main scanning direction, and that is arranged alongside the first post-processing nozzle arrangement region in the main scanning direction; An inkjet recording apparatus comprising:

6. 6. The inkjet recording apparatus according to claim 1, a holding member that holds the carriage in a state in which the carriage can move back and forth in the main scanning direction; the carriage includes an engagement portion and is held by the engagement portion in a cantilevered state on the holding member; an inkjet recording apparatus, wherein the pre-processing nozzle arrangement region is arranged closer to the engaging portion than the post-processing nozzle arrangement region in the transport direction;

7. 6. The inkjet recording apparatus according to claim 1, a holding member that holds the carriage in a state in which the carriage can move back and forth in the main scanning direction; the carriage includes an engagement portion and is held by the engagement portion in a cantilevered state on the holding member; an inkjet recording apparatus, wherein one of the pre-processing nozzle arrangement region and the post-processing nozzle arrangement region, whichever has a smaller number of nozzles, is arranged on the engagement portion side of the carriage;

8. 8. The inkjet recording apparatus according to claim 1, a holding member that holds the carriage in a state that allows it to move back and forth in the main scanning direction; the carriage includes an engagement portion and is held by the engagement portion in a cantilevered state on the holding member; An inkjet recording device, wherein of the pre-processing nozzle arrangement area and the post-processing nozzle arrangement area, the nozzle arrangement area that is located closest to the engagement portion of the carriage is located at a position excluding the ends in the main scanning direction of the nozzle arrangement area array of the pre-processing nozzle arrangement area, the ink nozzle arrangement area, and the post-processing nozzle arrangement area.

9. 9. The inkjet recording apparatus according to claim 1, the plurality of same-color ink nozzle arrangement regions include n (n is an integer of 2 or greater) same-color ink nozzle arrangement regions that are arranged at mutually different positions in the transport direction, The plurality of same-color ink nozzle arrangement areas are a downstream ink nozzle arrangement area that is arranged at a position closest to the post-processing nozzle arrangement area in the transport direction; at least one upstream ink nozzle arrangement region disposed between the pretreatment nozzle arrangement region and the downstream ink nozzle arrangement region in the transport direction; Each of these includes further comprising an ejection nozzle arrangement area designation unit that designates an ejection ink nozzle arrangement area, which is an ink nozzle arrangement area that ejects the ink, from among the n same-color ink nozzle arrangement areas, in order to cause the ink to land at a predetermined position on the recording medium based on predetermined image information; an inkjet recording device, wherein the ejection nozzle arrangement area designation unit, when ejecting the ink from n-1 or less same-color ink nozzle arrangement areas based on the image information, designates the ejection ink nozzle arrangement area so that the ink is ejected from the upstream ink nozzle arrangement area among the n same-color ink nozzle arrangement areas and not from the downstream ink nozzle arrangement area.

10. 10. The inkjet recording apparatus according to claim 9, The n is an integer of 3 or more, an inkjet recording device, wherein when the ink is to be ejected from n-2 or less same-color ink nozzle arrangement areas based on the image information, the ejection nozzle arrangement area designation unit designates the ejection ink nozzle arrangement area preferentially from the same-color ink nozzle arrangement area located upstream in the transport direction among the upstream ink nozzle arrangement areas.

11. 11. The inkjet recording apparatus according to claim 10, a storage unit that stores one or more pieces of ejection pattern information related to a combination of the number of the ejection ink nozzle arrangement areas and the amount of ink ejected from each of the ejection ink nozzle arrangement areas, the combination being information referenced by the ejection nozzle arrangement area designation unit in order to form an image at a predetermined density on the recording medium; the ejection pattern information includes a plurality of specific ejection pattern information items each having a different number of ejection ink nozzle arrangement regions, the specific ejection pattern information items being stored in correspondence with at least one density, The inkjet recording device has an ejection nozzle arrangement area designation unit that, when recording an image at the density corresponding to and stored in the plurality of specific ejection pattern information, selects the specific ejection pattern information with the smallest number of ejection ink nozzle arrangement areas from the plurality of specific ejection pattern information and designates the ejection ink nozzle arrangement area.

12. 10. The inkjet recording apparatus according to claim 9, a storage unit that stores a plurality of ejection pattern information related to combinations of the number of ejection ink nozzle arrangement areas and the amount of ink ejected from each of the ejection ink nozzle arrangement areas, the combination being information referenced by the ejection nozzle arrangement area designation unit in order to form an image at a predetermined density on the recording medium; the ejection pattern information includes at least first pattern information for ejecting the ink from n same-color ink nozzle arrangement regions, and second pattern information for ejecting the ink from n-1 or less same-color ink nozzle arrangement regions, An inkjet recording device, wherein the ejection nozzle arrangement area designation unit, when designating the ejection ink nozzle arrangement area based on the second pattern information, designates the ejection ink nozzle arrangement area so that the ink is ejected from the upstream ink nozzle arrangement area and not ejected from the downstream ink nozzle arrangement area.

13. 9. The inkjet recording apparatus according to claim 1, The plurality of same-color ink nozzle arrangement areas are a downstream ink nozzle arrangement area that is arranged at a position closest to the post-processing nozzle arrangement area in the transport direction; at least one upstream ink nozzle arrangement region disposed between the pretreatment nozzle arrangement region and the downstream ink nozzle arrangement region in the transport direction; Each of these includes an inkjet recording device, wherein all ejections that land ink of the same color at a predetermined position on the recording medium based on predetermined image information are either ejections that eject ink from the upstream ink nozzle arrangement region and do not eject ink from the downstream ink nozzle arrangement region, or ejections that eject ink from both the upstream ink nozzle arrangement region and the downstream ink nozzle arrangement region.

14. 14. The inkjet recording apparatus according to claim 1, The recording medium is made of fabric, The inkjet recording apparatus is configured such that the pretreatment liquid lands on the predetermined position on the fabric before the ink lands on the predetermined position.

15. 15. The inkjet recording apparatus according to claim 1, The recording medium is made of fabric, The inkjet recording apparatus is configured such that the post-treatment liquid lands on the predetermined position on the fabric after the ink.

16. 16. The inkjet recording apparatus according to claim 1, an ink jet recording apparatus, wherein the ink nozzle arrangement region ejects the ink so that the ink lands on top of the pretreatment liquid ejected onto the recording medium from the pretreatment nozzle arrangement region;

17. conveying the recording medium in a predetermined conveying direction; reciprocating the carriage in a main scanning direction intersecting the transport direction; disposing at least one head on the carriage, the head having a nozzle arrangement area formed on a lower surface thereof for ejecting liquid; ejecting ink onto the recording medium from a plurality of ink nozzle arrangement areas that are the nozzle arrangement areas in the lower surface portion of the at least one head, the plurality of ink nozzle arrangement areas being arranged side by side in the transport direction, at different positions in the main scanning direction, and arranged so as to partially overlap each other in the transport direction, the plurality of same-color ink nozzle arrangement areas ejecting ink of the same color; ejecting a non-color-forming pretreatment liquid onto the recording medium from at least one pretreatment nozzle arrangement area, which is a nozzle arrangement area that is arranged upstream of the ink nozzle arrangement areas in the transport direction in the lower surface portion of the at least one head; ejecting a non-color-forming post-treatment liquid onto the recording medium from at least one post-treatment nozzle arrangement area, which is a nozzle arrangement area of ​​the lower surface portion of the at least one head, that is arranged downstream of the plurality of ink nozzle arrangement areas in the transport direction; An inkjet recording method comprising:

18. 18. The inkjet recording method according to claim 17, an ink jet recording method, wherein the ink nozzle arrangement region ejects the ink so that the ink lands on top of the pretreatment liquid ejected onto the recording medium from the pretreatment nozzle arrangement region;

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