Inkjet recording device, inkjet recording method, and printing method

Abstract

To secure a necessary discharge amount of ink and processing liquid while miniaturizing a carriage.SOLUTION: The inkjet recording apparatus includes a conveyor, a carriage, an ink head, and a plurality of processing heads. The conveyance section conveys a recording medium in a predetermined conveyance direction. The carriage reciprocates in a main scanning direction intersecting the conveyance direction. The ink heads are mounted on the carriage so as to be aligned in the main scanning direction and eject ink for image formation. The processing head is mounted on the carriage and ejects a non-color developing processing liquid. The plurality of processing heads are arranged side by side in the main scanning direction at positions different from the ink head in the conveyance direction.SELECTED DRAWING: Figure 1

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 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 processing head, respectively. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-147307 Summary of the Invention

[0005] An inkjet recording device according to one aspect of the present disclosure comprises a transport unit that transports a recording medium in a predetermined transport direction, a carriage that moves back and forth in a main scanning direction that intersects the transport direction, a plurality of ink heads that are mounted on the carriage so as to be aligned in the main scanning direction and that eject ink for image formation, and a plurality of processing heads that are mounted on the carriage and that eject non-color-forming processing liquid, wherein the plurality of processing heads are arranged side by side in the main scanning direction at positions different from the ink heads in the transport direction. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view showing the overall configuration of an inkjet printer according to an 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 this embodiment. [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 showing the arrangement of the ink heads and the processing heads in the carriage shown in FIG. 3, and schematically showing the head arrangement according to the first embodiment. [Figure 7] FIG. 7 is a plan view of a carriage showing a head arrangement according to the second embodiment. [Figure 8] FIG. 8 is a plan view of a carriage showing a head arrangement according to the third embodiment. [Figure 9] FIG. 9 is a plan view of a carriage showing a head arrangement according to the fourth embodiment. [Figure 10] FIG. 10 is a plan view of a carriage showing a head arrangement according to the fifth embodiment. [Figure 11]FIG. 11 is a plan view of a carriage showing a head arrangement according to the sixth embodiment. [Figure 12] FIG. 12 is a plan view of a carriage showing a head arrangement according to the seventh embodiment. [Figure 13] FIG. 13 is a plan view of a carriage showing a head arrangement according to the eighth embodiment. [Figure 14A] FIG. 14A is a plan view of a carriage showing a head arrangement according to a ninth embodiment. [Figure 14B] FIG. 14B is a plan view of the carriage showing the head arrangement according to the ninth embodiment. [Figure 14C] FIG. 14C is a plan view showing a comparative example to Example 9. [Figure 15A] FIG. 15A is a plan view of a carriage showing a head arrangement according to a tenth embodiment. [Figure 15B] FIG. 15B is a plan view of the carriage showing the head arrangement according to the tenth embodiment. [Figure 15C] FIG. 15C is a plan view of the carriage showing the head arrangement according to the tenth embodiment. [Figure 15D] FIG. 15D is a plan view showing a comparative example for Example 10. [Figure 16] 16 is a plan view of a carriage showing the head arrangement and the sub-tank arrangement according to the eleventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] An embodiment of the present disclosure will be described below with reference to the drawings. In this embodiment, 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. The inkjet printer of this embodiment is 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.

[0008] [Overall configuration of inkjet printer] Fig. 1 is a perspective view showing the overall configuration of an inkjet printer 1 according to an 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-right direction is the main scanning direction 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).

[0009] 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 the work W so that the work W progresses in a transport direction F from rear to front through a printing area where inkjet printing processing 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 the left and right directions during the inkjet printing processing.

[0010] 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.

[0011] 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 and purging processes are performed on the ejection ports of the ink head 4, pre-processing head 5, and post-processing head 6, and caps are also fitted. The left frame 113 forms the turn-back area 14 for the carriage 3. The turn-back area 14 is an area where the carriage 3 temporarily enters after scanning the printing area 12 from right to left during the printing process, before scanning in the opposite direction.

[0012] A carriage guide 15 for moving the carriage 3 back and forth in the left-right direction is attached to the upper side of the device frame 10. 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 that is driven by a drive source (not shown) to move in a circular motion in the left or right direction.

[0013] The carriage guide 15 is equipped with a pair of upper and lower guide rails 17, which are holding members that hold the carriage 3, extending parallel to the left and right. 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 leftward or rightward, the carriage 3 moves leftward or rightward along the carriage guide 15 while being guided by the guide rails 17.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] 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.

[0018] The carriage 3 is supported at one end by a guide rail 17 and moves back and forth in a main scanning direction (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).

[0019] The head support frame 31 is a horizontal plate that holds the heads 4 to 6 described above. 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 engagement portion.

[0020] The cantilevered state refers to a state in which the engagement portion (back frame 32) of the carriage 3 is present 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 present on the opposite side of the side where the engagement portion is present. 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 arranged 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 arranged in the transport direction F.

[0021] [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.

[0022] Each ink head 4 includes 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 ink heads 4 include first to sixth ink heads 4A to 4F, each of which ejects six different colors of ink. For example, the first ink head 4A ejects orange (first color), the second ink head 4B ejects green (second color), the third ink head 4C ejects yellow, the fourth ink head 4D ejects red, the fifth ink head 4E ejects blue, and the sixth ink head 4F ejects black.

[0023] 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 head 4A1 located upstream in the transport direction F and a downstream head 4A2 located downstream of the upstream 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 upstream head of these ink heads 4B to 4F is aligned in the main scanning direction S at the same position as the upstream head 4A1 in the transport direction F, and each downstream head is aligned in the main scanning direction S at the same position as the downstream head 4A2 in the transport direction F.

[0024] The pre-treatment head 5 and post-treatment head 6 are arranged at different positions from the ink head 4 in the transport direction F. The pre-treatment head 5 is arranged upstream of the ink head 4 in the transport direction F. FIG. 3 shows an example in which one pre-treatment head 5 is arranged near the right end of the array of ink heads 4. In contrast, the post-treatment head 6 is arranged downstream of the ink head 4 in the transport direction F. FIG. 3 shows an example in which two post-treatment heads 6A and 6B (multiple processing heads) are arranged side by side in the main scanning direction S near the right end of the array of ink heads 4. Various arrangement patterns of the ink head 4, pre-treatment head 5, and post-treatment head 6 on the carriage 3 will be described in detail in Examples 1 to 11 below.

[0025] 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-treatment heads 6, is referred to as a head row, or simply as a row. A head row may also include a pre-treatment head 5. Furthermore, a series of heads along the transport direction F, which is made up of ink heads 4, pre-treatment heads 5, and post-treatment heads 6, is referred to as a head row, or simply as a row.

[0026] The pretreatment head 5 ejects a pretreatment liquid for performing a predetermined pretreatment on the workpiece W. The pretreatment liquid is ejected from the pretreatment head 5 onto a position on the workpiece W where 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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 the portion where no color is to be printed, i.e., the portion where no ink is ejected, the pretreatment liquid and the posttreatment liquid are basically not ejected either. Note that, in order to adjust the print image quality and the texture of the workpiece W, some of the ejection of the pretreatment liquid and the posttreatment liquid may be selected to be different from the ejection of the ink.

[0031] Openings 31H 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.

[0032] 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. 16).

[0033] 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, the pre-treatment head 5, and the post-treatment head 6 - are mounted on a single carriage 3. With this 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.

[0034] [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.

[0035] 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 the workpiece W is intermittently fed in the transport direction F, repeatedly. Here, the ink heads 4 have a predetermined printing width Pw in the transport direction F. The printing width Pw is approximately equal to the range in which the ink ejection nozzles of the ink heads 4 are arranged.

[0036] 4 and the next explained Fig. 5, the width of each head in the transport direction F is depicted as being approximately equal to the printing width Pw. In reality, the width of each head in the transport direction F is greater than the printing width Pw and the arrangement range of the ejection nozzles.

[0037] 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 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.

[0038] 5A and 5B are schematic diagrams showing printing conditions on the outbound and return passes of the carriage 3. The ink head 4, pre-processing head 5, and post-processing 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 first, second, third, and fourth colors, respectively, and these first to fourth ink heads 4A to 4D are aligned in a row in the main scanning direction S. The pre-processing head 5 is located upstream of the ink head 4 in the transport direction F, and the post-processing head 6 is located downstream.

[0039] 5A shows a state in which the carriage 3 is performing a printing operation (forward scan) while moving in the forward direction SA in the main scanning direction S. Area A4 on the workpiece W is an area that faces the pre-treatment head 5 mounted on the most upstream side of the carriage 3. During this forward scan, a pre-treatment layer Lpre is formed on area A4 by the pre-treatment liquid ejected from the pre-treatment head 5.

[0040] Region A3 is one scan 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 scan. During this forward scan, 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. The pre-treatment layer Lpre described above and the post-treatment layer Lpos described below are not formed on the workpiece W.

[0041] Area A2 is one scan downstream of area A3 and faces the post-processing head 6 mounted on the most downstream side of the carriage 3. A pre-processing layer Lpre from the previous forward scan and first to fourth ink layers LCA to LCD from the previous backward scan have already been formed on area A2 over the entire length in the main scanning direction. During this forward scan, a post-processing layer Lpos is formed on the first to fourth ink layers LCA to LCD in area A2 by the post-processing liquid ejected from the post-processing head 6.

[0042] Region A1 is one scan 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.

[0043] 5B shows the state in which, after the forward scan in FIG. 5A is completed, the carriage 3 turns around and moves in the return direction SB while performing a return scan. Before the return movement, the workpiece W is sent out one pitch in the transport direction F. Area A5 on the workpiece W is an area one scan upstream of area A4, and is the area that the pre-treatment head 5 faces in this return scan. A pre-treatment layer Lpre is formed on area A5 by the pre-treatment liquid ejected from the pre-treatment head 5.

[0044] 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.

[0045] The reason why printing is possible in both forward and backward scans as described above is because the pre-treatment head 5 and 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 scanning direction S on the carriage 3, printing that ensures the desired landing order of the pre-treatment liquid and post-treatment liquid could only be achieved in either the forward or backward scan. To enable bidirectional printing, the pair of pre-treatment head 5 and post-treatment head 6 would have to be arranged on both sides of the ink head 4 array. In this case, the width of the carriage 3 in the main scanning direction S would increase. This arrangement is unnecessary in this embodiment, so the width of the carriage 3 in the main scanning direction S can be reduced.

[0046] [Various head arrangements] Below, various examples of the arrangement of the ink head 4, pre-processing head 5, and post-processing head 6 on the carriage 3 are illustrated as Examples 1 to 11. In Examples 1 to 11, the processing heads include both the pre-processing head 5 and the post-processing head 6. However, as long as multiple copies of at least one of the pre-processing head 5 or post-processing head 6 are provided and are arranged side by side in the main scanning direction at positions different from the ink heads 4 in the transport direction F, one of the pre-processing head 5 or post-processing head 6 can be omitted.

[0047] Example 1 FIG. 6 is a plan view showing a schematic head arrangement according to the first embodiment. FIG. 6 is also a diagram showing the arrangement of the ink head 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 head support frame 31 of the carriage 3 is equipped with the first to sixth ink heads 4A to 4F, which eject ink of six different colors, the pre-processing head 5, and the post-processing head 6. Each of the ink heads 4A to 4F of each color has two unit heads (12 in total). There is one pre-processing head 5, but two post-processing heads 6.

[0048] 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 upstream of the ink heads 4 in the transport direction F, at the base end side 311 of the head support frame 31. Meanwhile, the post-processing head 6 is located downstream of the ink heads 4 in the transport direction F, at the tip end side 312 of the head support frame 31. Both the pre-processing head 5 and the post-processing head 6 are located near one end (the right end) of the head support frame 31 in the main scanning direction S.

[0049] The first ink head 4A includes an upstream head 4A1 and a downstream head 4A2 disposed downstream of the upstream head 4A1. That is, the upstream head 4A1 and the downstream head 4A2 are arranged in the transport direction F. The upstream head 4A1 is disposed closer to the base end 311 in the central region of the head support frame 31. The downstream head 4A2 is disposed closer to the tip end 312 in the central region of the head support frame 31. The downstream head 4A2 is disposed shifted to one side (left side) in the main scanning direction S relative to the upstream head 4A1, and is disposed in a position that partially overlaps with the transport direction F. Of course, the upstream head 4A1 and the downstream 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 of this embodiment is advantageous in that it allows for a reduction in the size of the carriage 3 in the transport direction F.

[0050] The second to sixth ink heads 4B to 4F also include upstream heads 4B1, 4C1, 4D1, 4E1, and 4F1 and downstream heads 4B2, 4C2, 4D2, 4E2, and 4F2, similar to the upstream head 4A1 and downstream head 4A2 described above. The upstream 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 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 in which a portion of the downstream heads 4A2 to 4F2 is inserted between each of the arrangement pitches of the upstream heads 4A1 to 4F1.

[0051] The pre-treatment head 5 is disposed so that a portion of it is sandwiched between a pair of adjacent ink heads in the main scanning direction S. Specifically, the positional relationship is such that the downstream portion of the pre-treatment head 5 is sandwiched between the upstream head 4E1 of the fifth ink head 4E and the upstream head 4F1 of the sixth ink head 4F.

[0052] The post-processing head 6 includes a first post-processing head 6A and a second post-processing head 6B arranged side by side in the main scanning direction S. FIG. 6 shows an example in which the first and second post-processing heads 6A and 6B are arranged at the same position in the transport direction F and at a predetermined interval in the main scanning direction S. The first post-processing head 6A is arranged between the downstream head 4E2 of the fifth ink head 4E and the downstream head 4F2 of the sixth ink head 4F, with its upstream portion intervening. The second post-processing head 6B is arranged to the right of the downstream head 4F2 and at the same position in the main scanning direction S as the upstream head 4F1. This arrangement results in an overlapping area fa between the first and second post-processing heads 6A and 6B and the downstream heads 4E2 and 4F2 in the transport direction F.

[0053] The width of each head is greater than the printing width Pw and the arrangement range of the ejection nozzles in the transport direction F. For this reason, the heads are arranged to have an overlapping area fa so that there is no space between the printing width Pw of the heads in each row and the printing range Pw of the heads in the adjacent row.

[0054] 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, extending from the downstream head 4A2 of the first ink head 4A to the upstream head 4F1 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.

[0055] The head arrangement according to the first embodiment described above ensures the necessary ink and treatment liquid ejection volumes while miniaturizing the carriage 3. That is, the pre-treatment head 5 and post-treatment head 6 are arranged at different positions in the transport direction F from the ink head 4. This configuration allows the ink heads 4A to 4F, which can ensure the necessary ink ejection volumes, to be arranged in the main scanning direction S, and enables printing processes in both forward and backward scans, while shortening the main scanning direction width of the carriage required to mount the heads 4 to 6. Furthermore, the post-treatment head 6 is composed of a plurality of first and second post-treatment heads 6A and 6B, which are arranged side by side in the main scanning direction S. Therefore, even if a single head does not eject enough post-treatment liquid, the necessary ejection volume can be ensured by arranging multiple post-treatment heads 6A and 6B.

[0056] The first to sixth ink heads 4A to 4F each comprise upstream heads 4A1 to 4F1 and downstream heads 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 possible to prevent the width of the carriage 3 in the main scanning direction from increasing.

[0057] The pre-processing head 5 and post-processing head 6 are arranged within the range of the arrangement width H of the first to sixth ink heads 4A to 4F in the main scanning direction S. 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 increase the width of the carriage 3 in the main scanning direction. In other words, it is possible to prevent the width of the carriage 3 from becoming large in the main scanning direction.

[0058] The pre-processing head 5 and post-processing head 6 are arranged so that some of them fit between the arrangement pitches of the first to sixth ink heads 4A to 4F. Looking at the first post-processing head 6A, a portion of the first post-processing head 6A fits between the pair of downstream heads 4E2 and 4F2. This staggered arrangement allows the ink heads 4 and processing heads 5 and 6, which are arranged at different positions in the transport direction F, to be arranged at high density in the transport direction F. This allows the width of the carriage 3 in the transport direction F to be reduced.

[0059] In the head arrangement of Example 1, one pre-treatment head 5 is arranged upstream of the ink head 4 in the transport direction F, and two post-treatment heads 6A and 6B are arranged downstream. In other words, it is possible to provide an all-in-one inkjet printer 1 in which all of the 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 in sequence in the transport direction F, it is possible to ensure the desired landing order of the pre-treatment liquid, ink, and post-treatment liquid on the workpiece W in both the forward scan and the backward scan.

[0060] The carriage 3 also 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. Furthermore, 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.

[0061] In the carriage 3 supported in a cantilevered manner in this manner, the pre-processing head 5 is disposed on the base end side 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 side 312 (the side farther from the engagement portion). Unlike the base end side 311, which is close to the back frame 32 fixed to the timing belt 16, it is expected that the positional accuracy will inevitably decrease on the tip end side 312, which is the free end. However, the tip end side 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 can be smaller than if a similar misalignment in the landing position occurs with the pre-processing liquid. Therefore, even when a cantilevered carriage 3 is used, degradation of image quality is less likely to occur.

[0062] <Example 2> FIG. 7 is a plan view schematically illustrating a carriage 3A equipped with a head arrangement according to Example 2. The head arrangement technique is the same as in Example 1, but differs from Example 1 in that the number of unit heads is increased. That is, Example 2 is the same as Example 1 in that each ink head 4 includes first to sixth ink heads 4A to 4F that eject six different colors of ink. On the other hand, in Example 2, each of the ink heads 4A to 4F for each color includes three unit heads (18 in total). The pre-treatment head 5, which is arranged upstream of the ink head 4 in the transport direction F, includes two unit heads, and the post-treatment head 6, which is arranged downstream, includes three unit heads. Also, as in Example 1, the pre-treatment head 5 and the post-treatment head 6 are each arranged within the arrangement width of the ink head 4 in the main scanning direction S.

[0063] The first ink head 4A includes an upstream head 4AA, a central head 4AB, and a downstream head 4AC as the unit heads. The upstream head 4AA is disposed on the most upstream side of the carriage 3A in the transport direction F. The downstream head 4AC is disposed downstream of the upstream head 4AA at the same position in the main scanning direction S as the upstream head 4AA. The central head 4AB is shifted to the right in the main scanning direction S relative to the upstream head 4AA and downstream head 4AC, and is disposed downstream of the upstream head 4AA and upstream of the downstream head 4AC in the transport direction F. The central head 4AB is disposed in a position that partially overlaps with the upstream head 4AA and downstream head 4AC in the transport direction F.

[0064] The second to sixth ink heads 4B to 4F also include upstream heads 4BA, 4CA, 4DA, 4EA, and 4FA, central heads 4BB, 4CB, 4DB, 4EB, and 4FB, and downstream heads 4BC, 4CC, 4DC, 4EC, and 4FC, similar to the upstream head 4AA, central head 4AB, and downstream head 4AC described above. The upstream heads 4AA to 4FA, central heads 4BB to 4FB, and downstream heads 4BC to 4FC 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.

[0065] The pre-processing heads 5 include a first pre-processing head 5A and a second pre-processing head 5B that are arranged side by side at an interval in the main scanning direction S and at the same position in the transport direction F. The first pre-processing head 5A is arranged between the upstream head 4EA of the fifth ink head 4E and the upstream head 4FA of the sixth ink head 4F, with a portion of its downstream side inserted in. The second pre-processing head 5B is arranged to the right of the upstream head 4FA and at the same position in the main scanning direction S as the central head 4FB.

[0066] The post-processing heads 6 include a first post-processing head 6A, a second post-processing head 6B, and a third post-processing head 6C, which are arranged at the same position in the transport direction F and spaced apart in the main scanning direction S. The first post-processing head 6A is arranged between the downstream head 4DC of the fourth ink head 4D and the downstream head 4EC of the fifth ink head 4E, with a portion of its upstream side intervening. The second post-processing head 6B is arranged between the downstream head 4EC of the fifth ink head 4E and the downstream head 4FC of the sixth ink head 4F, with a portion of its upstream side intervening. The third post-processing head 6C is arranged to the right of the downstream head 4FC, at the same position in the main scanning direction S as the central head 4FB.

[0067] The head arrangement according to the second embodiment provides the same advantages as those of the first embodiment. That is, it is possible to ensure the necessary ejection amounts of ink and treatment liquid while miniaturizing the carriage 3A. In particular, in the second embodiment, since both the pre-treatment head 5 and the post-treatment head 6 are configured to include a plurality of unit heads, it is possible to ensure sufficient ejection amounts of pre-treatment liquid and post-treatment liquid. The first to sixth ink heads 4A to 4F also include unit heads arranged in three rows, so it is possible to ensure sufficient ejection amounts of ink.

[0068] Example 3 8 is a plan view schematically illustrating a carriage 3B equipped with a head arrangement according to Example 3. Example 3 illustrates an example in which an ink head 4 that ejects ink, and a pre-treatment head 5 and a post-treatment head 6 that eject a non-color-forming treatment liquid are arranged separately in the main scanning direction.

[0069] The head support frame 31 of the carriage 3B is mounted with first to sixth ink heads 4A to 4F, each of which ejects six different colors of ink, a pre-processing head 5, and a post-processing head 6. The first to sixth ink heads 4A to 4F are equipped with unit heads arranged in three rows, similar to those in the second embodiment. The pre-processing head 5 includes first and second pre-processing heads 5A and 5B, which are arranged at the same position in the transport direction F and spaced apart in the main scanning direction S. The post-processing head 6 includes first to third post-processing heads 6A to 6C, which are arranged at the same position in the transport direction F and spaced apart in the main scanning direction S. The basic configuration of these is the same as that in the second embodiment.

[0070] In Example 3, the head support frame 31 is divided into an arrangement area for the ink heads 4 and an arrangement area for the pre-processing head 5 and post-processing head 6. The head support frame 31 has a first region R1 with a relatively large area and a second region R2 with a relatively small area adjacent to the first region R1 in the main scanning direction S. The ink heads 4 (first to sixth ink heads 4A to 4F) are arranged in the first region R1. The pre-processing head 5 and post-processing head 6 are not arranged in the first region R1, but in the second region R2. In the second region R2, the pre-processing head 5 is arranged upstream of the ink head 4 array in the transport direction F, and the post-processing head 6 is arranged downstream.

[0071] When ink comes into contact with the pre-treatment liquid or post-treatment liquid, ink components may aggregate. In this case, if the aggregate adheres to the ink ejection nozzles of the ink head 4, ejection problems may occur. There is also a concern that ink may come into contact with the treatment liquid and aggregate, clogging the recovery path in a recovery system for waste liquid generated during head cleaning and purging processes. With the carriage 3B of the third embodiment, the treatment heads 5 and 6 and the ink head 4 are arranged separately in the main scanning direction, making it difficult for the ink to come into contact with the pre-treatment liquid or post-treatment liquid. This makes it difficult for problems caused by ink aggregation to occur.

[0072] Example 4 9 is a plan view that schematically shows a carriage 3C equipped with a head arrangement according to Example 4. In Examples 1 to 3 above, examples were shown in which the pre-processing head 5 and post-processing head 6 were arranged near the end (near the right end) of the arrangement width H in the main scanning direction S of the ink head 4. Example 4 shows an example in which the pre-processing head 5 and post-processing head 6 are arranged in the central region HC of the arrangement width H.

[0073] The head support frame 31 of the carriage 3C is equipped with first to sixth ink heads 4A to 4F, each of which ejects six different colors of ink, a pre-processing head 5, and a post-processing head 6. The first to sixth ink heads 4A to 4F are equipped with unit heads arranged in two rows, similar to Example 1. However, the shift direction of the downstream heads of each of the ink heads 4A to 4F is opposite to Example 1, with the downstream head 4A2 of the first ink head 4A being positioned to the right of the upstream head 4A1. There is one pre-processing head 5, and two post-processing heads 6, first and second post-processing heads 6A and 6B.

[0074] The pre-treatment head 5 and post-treatment head 6 are arranged in a central region HC of the first to sixth ink heads 4A to 4F across an arrangement width H in the main scanning direction S. As with the above-described first to third embodiments, the pre-treatment head 5 is arranged upstream of the arrangement of the first to sixth ink heads 4A to 4F in the transport direction F, and the post-treatment head 6 is arranged downstream. The pre-treatment head 5 is arranged at the same position in the main scanning direction S as the downstream head 4C2 of the third ink head 4C, and on the upstream side in the transport direction F. The pre-treatment head 5 is arranged between the upstream heads 4C1 and 4D1 of the third and fourth ink heads 4C and 4D, with a portion of its downstream side sandwiched between them.

[0075] The first and second post-processing heads 6A and 6B are aligned at the same position in the transport direction F and spaced a predetermined distance apart in the main scanning direction S. The first post-processing head 6A is positioned such that its upstream portion is between the downstream head 4B2 of the second ink head 4B and the downstream head 4C2 of the third ink head 4C. The second post-processing head 6B is positioned such that its upstream portion is between the downstream head 4C2 and the downstream head 4D2 of the fourth ink head 4D.

[0076] The pre-processing head 5 and post-processing head 6 are not only arranged in the central region HC of the arrangement width H, but are also arranged so that the arrangement center of the pre-processing head 5 coincides with the arrangement center of the first and second post-processing heads 6A and 6B in the main scanning direction S. In this embodiment, there is only one pre-processing head 5, so the center of the pre-processing head 5 in the main scanning direction S is the arrangement center C1. For the post-processing head 6, the midpoint between the first post-processing head 6A and the second post-processing head 6B is the arrangement center C2. The pre-processing head 5 and post-processing head 6 are arranged on the head support frame 31 so that the arrangement center C1 and the arrangement center C2 are in the same position in the main scanning direction S.

[0077] 4, in this embodiment, the carriage 3 repeats forward and backward scans to sequentially deposit pre-treatment liquid, ink, and post-treatment liquid on the workpiece W. When such bidirectional scanning is employed, by employing the head arrangement of Example 4, it is possible to reduce the variation in the time from when the pre-treatment liquid lands on the workpiece W until the ink lands, and the variation in the time from when the ink lands on the workpiece W, at each main scanning position.

[0078] In this case, the central region HC is a region located in the center of the range of the arrangement width H, with a width that is half or one-third of the arrangement width H. The processing heads being arranged in the central region HC means that the centers of the arrangement of the processing heads are arranged in the central region HC, and that more than half of the arrangement centers of the processing heads are arranged in the central region HC. Furthermore, all of the arrangement centers of the processing heads may be arranged in the central region HC.

[0079] <Example 5> 10 is a plan view schematically illustrating a carriage 3D equipped with a head arrangement according to Example 5. Example 5 illustrates an example in which the pre-processing head 5 and the post-processing head 6 are separately arranged on one end side and the other end side of the head support frame 31 in the main scanning direction S, sandwiching the ink head 4 therebetween.

[0080] The head support frame 31 is equipped with the first to sixth ink heads 4A to 4F, pre-processing head 5, and post-processing head 6, arranged in the same manner as in Example 4 (FIG. 9). There is one pre-processing head 5 and two post-processing heads 6, the first and second post-processing heads 6A and 6B. The pre-processing head 5 is located at one end (right side) of the ink head 4 in the main scanning direction S and upstream in the transport direction F. The first and second post-processing heads 6A and 6B are located at the other end (left side) of the ink head 4 in the main scanning direction S and downstream in the transport direction F. The first and second post-processing heads 6A and 6B are aligned at the same position in the transport direction F and spaced apart in the main scanning direction S.

[0081] As in Example 3, the head arrangement in Example 5 is also an example in which the arrangement area of ​​the ink head 4 and the arrangement area of ​​the pre-treatment head 5 and post-treatment head 6 are separated on the head support frame 31. That is, the right end portion of the head support frame 31 is the arrangement area of ​​the pre-treatment head 5, the left end portion is the arrangement area of ​​the post-treatment head 6, and the remaining central area is the arrangement area of ​​the ink head 4. This head arrangement in Example 5 also makes it possible to reduce the likelihood of contact between the ink and the pre-treatment liquid or the post-treatment liquid.

[0082] Example 6 11 is a plan view schematically illustrating a carriage 3E equipped with a head arrangement according to Example 6. In each of the above-described Examples, an ink head 4 equipped with an independent unit head for each color was exemplified. Example 6 illustrates an ink head 4 equipped with ejection portions that eject inks of different colors in a single head.

[0083] The carriage 3E is equipped with two multi-color heads 40A and 40B, one pre-processing head 5, and a post-processing head 6 equipped with first and second post-processing heads 6A and 6B. The multi-color heads 40A and 40B are equipped with first, second, third, and fourth ink ejection regions 4a, 4b, 4c, and 4d, which respectively eject four different color inks. The first to fourth ink ejection regions 4a to 4d may be formed by combining unit nozzles that eject each color ink, or may be formed by vertically dividing the multiple ink ejection nozzles of a single ink head into ejection regions for each color ink.

[0084] The pre-processing head 5 is disposed on the right side of the array of multi-color heads 40A, 40B, upstream in the transport direction F. The post-processing head 6 is disposed downstream of the array in the transport direction F. The first and second post-processing heads 6A, 6B are aligned at the same position in the transport direction F, with a predetermined distance between them in the main scanning direction S. Of these, the first post-processing head 6A is disposed so that its upstream portion is inserted between the pair of multi-color heads 40A, 40B. This head arrangement according to Example 6 also makes it possible to miniaturize the carriage 3E while ensuring the necessary amount of ink and treatment liquid ejected.

[0085] Example 7 12 is a plan view schematically illustrating a carriage 3F equipped with a head arrangement according to Example 7. Example 7 illustrates an ink head 4 in which first to sixth ink heads 4A to 4F, each ejecting six different color inks, are arranged in a row in the main scanning direction S.

[0086] The head support frame 31 of the carriage 3F is mounted with first to sixth ink heads 4A to 4F, each having two unit heads, a pre-processing head 5, and a post-processing head 6. There is one pre-processing head 5, and two post-processing heads 6, a first and second post-processing head 6A and 6B. This embodiment differs from the above-described first to fifth embodiments in that the first to sixth ink heads 4A to 4F, each having two unit heads, are arranged in the main scanning direction S at the same position in the transport direction F. The pre-processing head 5 and post-processing head 6 are located on the upstream and lower sides, respectively, to the right of the arrangement of the first to sixth ink heads 4A to 4F.

[0087] The head arrangement of Example 7 allows for a relatively large width in the main scanning direction S, but is suitable for cases where the width in the transport direction F needs to be short. It also ensures the necessary ejection volumes of ink and treatment liquid. Furthermore, the arrangement area of ​​the ink heads 4 and the arrangement area of ​​the pre-treatment head 5 and post-treatment head 6 are separated on the head support frame 31, making it possible to prevent contact between the ink and the pre-treatment liquid or post-treatment liquid.

[0088] Example 8 Example 8 and the following Example 9 illustrate head arrangements in which measures are taken to prevent heat generation in the treatment heads 5 and 6. Generally, heads that eject liquid using a jet method generate heat because they use electricity to pressurize the liquid. The ink head 4 performs an ejection operation only when forming the required color dots. In contrast, the pre-treatment head 5 and post-treatment head 6 require ejection of pre-treatment liquid and post-treatment liquid corresponding to dots of all colors. Therefore, the pre-treatment head 5 and post-treatment head 6 are more likely to become hotter than the ink head 4. For this reason, it is desirable to perform a head arrangement that takes into account the possibility of the pre-treatment head 5 and post-treatment head 6 becoming hotter.

[0089] FIG. 13 is a plan view showing a carriage 3G having a head arrangement according to Example 8. The carriage 3G has a back frame 32 (engagement portion) supported at one end by a guide rail 17 (holding member). The head support frame 31 is equipped with an ink head 4 having first to sixth ink heads 4A to 4F, one pre-processing head 5, and a post-processing head 6 having first and second post-processing heads 6A and 6B. The head arrangement is the same as that of Example 1 shown in FIG. 6, so a description thereof will be omitted here.

[0090] 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 (first and second post-processing heads 6A and 6B). Of these pre-processing heads 5 and post-processing heads 6, the pre-processing head 5 having 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 having the most number of 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.

[0091] As described above, the processing heads 5 and 6 generate heat during the ejection operation. As shown schematically in FIG. 13, the pre-processing head 5, which has reached a high temperature, dissipates heat ha. The same is true for the first and second post-processing heads 6A and 6B. This heat ha warms the head support frame 31 of the carriage 3G, 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 3G is held in a cantilevered state.

[0092] However, in the carriage 3G of Example 8, 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.

[0093] Furthermore, in the carriage 3G of Example 8, the pre-processing head 5 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 and 6. Of the heads 4, 5, and 6 mounted on the carriage 3G, 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.

[0094] The carriage 3G cannot be unnecessarily large. If a head were 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 3G (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 could induce distortion or misalignment in the vertical and horizontal directions of the head support frame 31. This reduces the landing position accuracy of the heads 4, 5, and 6 mounted on the carriage 3G. 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.

[0095] In this embodiment, of the two rows of ink heads 4, the row of heads 4 located on the engagement portion side is arranged in a staggered position shifted to the right in Figure 13. Furthermore, a pre-processing head 5, which is a processing head with a smaller number of heads, is arranged on the engagement portion side, and the pre-processing head 5 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 edge 313.

[0096] A preferred ink head arrangement example will be described with reference to the head arrangement of the carriage 3G shown in Figure 13. In the carriage 3G, the pre-treatment head 5, which becomes hot, is arranged so that a portion thereof is adjacent to the ink head 4. Specifically, the pre-treatment head 5 is adjacent to the upstream heads 4E1 and 4F1 of the fifth and sixth ink heads 4E and 4F in the main scanning direction S, and adjacent to the downstream head 4F2 of the sixth ink head 4F in the transport direction F. Furthermore, the first post-treatment head 6A is adjacent to the downstream heads 4E2 and 4F2 of the fifth and sixth ink heads 4E and 4F in the main scanning direction S, and adjacent to the upstream head 4E1 in the transport direction F. The second post-treatment head 6B is adjacent to the upstream head 4F1 and the downstream head 4F2. On the other hand, the pre-treatment head 5 and post-treatment head 6 are not adjacent to the first to fourth ink heads 4A to 4D.

[0097] In the above head arrangement, for example, the fifth and sixth ink heads 4E and 4F (first ink heads ejecting ink of the first color), which eject blue and black ink, respectively, have a greater number of unit heads adjacent to the pre-treatment head 5 and post-treatment head 6 than the first to fourth ink heads 4A to 4D (second ink heads ejecting ink of the second color), which eject orange, green, yellow, and red ink, respectively. In other words, the fifth and sixth ink heads 4E and 4F are ink heads that are more likely to reach high temperatures than the other ink heads 4A to 4D.

[0098] When the viscosity of ink changes significantly with temperature, the ink ejection characteristics (e.g., ejection volume) from the ink heads also change. Temperature-dependent viscosity change characteristics differ depending on the type of ink. Therefore, in this embodiment, ink with a smaller viscosity change with temperature than the ink ejected from the first to fourth ink heads 4A to 4D is selected as the ink to be ejected from the fifth and sixth ink heads 4E and 4F, which are prone to high temperatures. This allows for smaller temperature-dependent changes in the ejection volume and ejection speed of the ink ejected from these ink heads 4E and 4F, even if the fifth and sixth ink heads 4E and 4F are heated by the pre-processing head 5 and post-processing head 6.

[0099] In this case, the number of unit heads of processing heads adjacent to an ink head 4 for each ink may be evaluated based on the maximum number of unit heads of adjacent processing heads among the ink heads 4 that eject a certain ink. For the first to fourth ink heads 4A to 4D, the maximum number of unit heads of adjacent processing heads is 0. For the fifth ink head 4E, the maximum number of unit heads of adjacent processing heads is 2. For the sixth ink head 4F, the maximum number of unit heads of adjacent processing heads is 3.

[0100] Furthermore, the number of unit heads of processing heads adjacent to an ink head 4 for each ink may be evaluated as the average number of unit heads of adjacent processing heads among the ink heads 4 that eject a certain ink. For the first to fourth ink heads 4A to 4D, the average number of unit heads of adjacent processing heads is 0. For the fifth ink head 4E, the average number of unit heads of adjacent processing heads is 1.5. For the sixth ink head 4F, the average number of unit heads of adjacent processing heads is 2.5.

[0101] As an evaluation combining these methods, for example, evaluation may be first performed using the maximum number of unit heads of adjacent processing heads, and for inks for which there is no difference in the evaluation, evaluation may be performed using the average number of unit heads of adjacent processing heads. Alternatively, the ink heads 4 ejecting each ink may be evaluated in order of how easily they heat up, and inks with the least change in viscosity with temperature may be ejected in order of how easily they heat up.

[0102] Example 9 Example 9 shows an example in which measures to prevent the pre-treatment head 5 and post-treatment head 6 from becoming too hot are taken into consideration between multiple ink heads of the same color that eject ink of the same color. In the above examples, examples were shown in which the first to sixth ink heads 4A to 4F of each color each include two or three unit heads. If there is a large difference in the number of unit heads adjacent to the pre-treatment head 5 or post-treatment head 6 between these unit heads, a problem occurs in which the ink ejection characteristics differ greatly between the unit heads. This example shows an example of a head arrangement that reduces the difference in the number of adjacent heads.

[0103] 14A is a plan view that schematically shows a carriage 3H-1 equipped with a head arrangement according to Example 9. The carriage 3H-1 has a head arrangement in which, when the number of two unit heads (ink heads of the same color) equipped in each of the first to sixth ink heads 4A to 4F that are adjacent to the pre-processing head 5 or the post-processing head 6 in the main scanning direction S and the transport direction F is counted, the difference between the maximum and minimum counts is 1 or less.

[0104] The head arrangement of carriage 3H-1 is the same as that of carriage 3G shown in Figure 13. Focusing on the fifth ink head 4E, as described above, if we count the processing heads 5, 6 adjacent to the upstream head 4E1 in the main scanning direction S and transport direction F, there are two (maximum), the pre-processing head 5 and the first post-processing head 6A. On the other hand, the only head adjacent to the downstream head 4E2 is the first post-processing head 6A (minimum), which is one. Therefore, the difference between the maximum and minimum counts is 1, which satisfies the above requirement.

[0105] Similarly, looking at the sixth ink head 4F, the count for the processing heads 5 and 6 adjacent to the upstream head 4F1 is 2 (minimum value), while the count for the downstream head 4F2 is 3 (maximum value), and the difference between the two is also 1. On the other hand, the first through fourth ink heads 4A through 4D do not have adjacent processing heads 5 and 6, so the counts for all of them are "0." Therefore, the differences between the maximum and minimum values ​​are all "0," satisfying the above requirement.

[0106] Figure 14B is a plan view schematically showing a carriage 3H-2 equipped with a head arrangement according to another example of the ninth embodiment. The arrangement of the first to sixth ink heads 4A to 4F on the carriage 3H-2 is the same as that shown in Figure 14A. The pre-processing head 5 includes first and second pre-processing heads 5A and 5B arranged side by side in the main scanning direction S, with the upstream head 4C1 of the third ink head 4C in between. The post-processing head 6 includes first and second post-processing heads 6A and 6B arranged side by side in the main scanning direction S, with the downstream head 4C2 in between.

[0107] For the second ink head 4B of carriage 3H-2, the counts of the processing heads 5 and 6 adjacent to the upstream head 4B1 and downstream head 4B2 are 2 and 1, respectively, with a difference of 1. For the third ink head 4C, the counts of the upstream head 4C1 and downstream head 4C2 are both 3, with a difference of 0. For the fourth ink head 4D, the count of the upstream head 4D1 is 1, and the count of the downstream head 4D2 is 2, with a difference of 1. The remaining ink heads 4A, 4E, and 4D all have a count of 0. Therefore, the difference between the maximum and minimum values ​​for all of the first through sixth ink heads 4A through 4F is 1 or less, satisfying the above requirement.

[0108] As described above, in Example 9, the difference between the maximum and minimum counts of the upstream heads 4A1 to 4F1 and the downstream heads 4A2 to 4F2 of the first to sixth ink heads 4A to 4F adjacent to the processing heads 5 and 6 is set to 1 or less. This prevents large differences in ink ejection volume between multiple ink heads of the same color.

[0109] 14C is a plan view schematically illustrating a carriage 3H-3 equipped with a head arrangement according to a comparative example (within the scope of this disclosure) of Example 9. Carriage 3H-3 is equipped with first through sixth ink heads 4A-4F, but differs from carriages 3H-1 and 3H-2 in that the upstream heads 4A1-4F1 are arranged in order from left to right, while the downstream heads 4A2-4F2 are arranged in the reverse order. The positions of the pre-processing head 5 and the first and second post-processing heads 6A and 6B are the same as those of carriage 3H-1.

[0110] Looking at the first ink head 4A in carriage 3H-3, the counts of the processing heads 5 and 6 adjacent to the upstream head 4A1 are 2 (maximum value), while the count of the downstream head 4A2 is 0 (minimum value), a difference of 2. In this case, the temperature difference between the upstream head 4A1 and the downstream head 4A2 becomes large while the inkjet printer 1 is operating, which can result in large discrepancies in the amount of ink ejected between these heads. This is undesirable because it can result in differences in color tone even though ink is ejected from the first ink head 4A, which has the same color.

[0111] Example 10 15A to 15C are plan views each schematically illustrating carriages 3I-1, 3I-2, and 3I-3 equipped with a head arrangement according to Example 10. Example 10 illustrates an example in which the pre-treatment head 5 and the post-treatment head 6 are arranged as a mass as possible, rather than being arranged dispersedly on the head support frame 31, thereby reducing contact between the pre-treatment liquid and the post-treatment liquid and the ink.

[0112] In Example 10, a head arrangement that satisfies the following requirements (A) to (C) is exemplified. (A) When the number of unit heads of the pre-processing heads 5 and the post-processing heads 6, whichever is larger, is m and whichever is smaller, is n, the requirement m = n + odd number is satisfied; (B) the center of arrangement or alignment of one or more pre-treatment heads 5 and the center of arrangement or alignment of one or more post-treatment heads 6 in the main scanning direction S coincide with each other in the main scanning direction S, and (C) The center of arrangement or alignment of the pre-treatment head 5 and the post-treatment head 6 and the position of one of the ink heads 4 coincide with each other in the main scanning direction S.

[0113] Furthermore, the head arrangement of Example 10 satisfies the following requirement (D). (D) The center of arrangement or alignment of the pre-processing head 5 and post-processing head 6 and the arrangement position of the m-th ink head row from the end in the main scanning direction S coincide in the main scanning direction S.

[0114] Here, a row refers to a unit that groups together heads lined up in the transport direction F. The m-th ink head row from the end in the main scanning direction S refers to the m-th ink head 4 row from the end of the head arrangement of the ink heads 4. By further satisfying the above requirement (D), the pre-treatment head 5 and the post-treatment head 6 can be arranged together, close to the end of the ink heads 4 in the main scanning direction S. This reduces the possibility of contact between the pre-treatment liquid and the post-treatment liquid and the ink on the carriage.

[0115] The carriage 3I-1 shown in Figure 15A is equipped with an ink head 4, one pre-processing head 5, and a post-processing head 6 having first and second post-processing heads 6A and 6B. The head arrangement is the same as in Figure 13 and other figures. In this example, there are m=2 post-processing heads 6 and n=1 pre-processing head 5. Therefore, the above requirement (A) of m=n+odd number is met. Furthermore, the centers of the pre-processing heads 5 and the post-processing head 6 are both center C in the figure, which also satisfies the above requirement (B). Furthermore, center C coincides with the arrangement position of the head 4F2 downstream of the sixth ink head 4F, which also satisfies the above requirement (C). Furthermore, the downstream head 4F2 is a head in the second ink head row from the right end, which also satisfies the above requirement (D).

[0116] The carriage 3I-2 shown in Figure 15B is equipped with an ink head 4, a pre-processing head 5 having first and second pre-processing heads 5A and 5B, and a post-processing head 6 having first, second, and third post-processing heads 6A, 6B, and 6C. In this example, there are m=3 post-processing heads 6 and n=2 pre-processing heads 5. Therefore, requirement (A) above is met: m=n+odd number. The centers of the arrangement of the pre-processing heads 5 and post-processing heads 6 are both center C in the figure, which also meets requirement (B). Furthermore, center C coincides with the position of the upstream head 4E1 of the fifth ink head 4E, which also meets requirement (C). Furthermore, the upstream head 4E1 is the head in the third ink head row from the right end, which also meets requirement (D) above.

[0117] The carriage 3I-3 shown in Figure 15C is equipped with an ink head 4, one pre-processing head 5, and a post-processing head 6 having first, second, third, and fourth post-processing heads 6A, 6B, 6C, and 6D. In this example, there are m=4 post-processing heads 6 and n=1 pre-processing head 5. Therefore, requirement (A) above is met, where m=n+odd number. The centers of the pre-processing heads 5 and the post-processing head 6 are both center C in the figure, which also meets requirement (B). Furthermore, center C coincides with the position of the downstream head 4E2 of the fifth ink head 4E, which also meets requirement (C). Furthermore, the downstream head 4E2 is a head in the fourth ink head row from the right end, which also meets requirement (D).

[0118] FIG. 15D is a plan view schematically illustrating a carriage 3I-4 equipped with a head arrangement according to a comparative example (within the scope of this disclosure) of Example 10. The carriage 3I-4 is equipped with an ink head 4, a pre-processing head 5 having first and second pre-processing heads 5A and 5B, and a post-processing head 6 having first, second, and third post-processing heads 6A, 6B, and 6C. This comparative example satisfies the above requirement (A), that is, m = n + odd number. However, the arrangement center C1 of the pre-processing head 5 and the arrangement center C2 of the post-processing head 6 are misaligned in the main scanning direction S, and therefore does not satisfy the above requirement (B). As a result, requirement (C) is also not satisfied.

[0119] According to the head arrangement of Example 10, the pre-treatment head 5 and the post-treatment head 6 can be mounted on the carriages 3I-1 to 3I-3 in a relatively compact state. This makes it possible to reduce the number of ink heads, out of the first to sixth ink heads 4A to 4F, that are arranged in positions close to the pre-treatment head 5 or the post-treatment head 6. This reduces the possibility of contact between the pre-treatment liquid and the post-treatment liquid and the ink on the carriage.

[0120] For example, compare carriage 3I-2, which has the same numbers of m and n, with carriage 3I-4 according to the comparative example. In the comparative example, the first and second post-processing heads 6A and 6B are shifted by one pitch in the main scanning direction S compared to the example. As a result, the number of unit heads of the ink heads 4 adjacent to the first to third post-processing heads 6A to 6C is increased in the comparative example. This undesirably increases the possibility of contact between the ink and the post-processing liquid compared to the example.

[0121] Example 11 In Example 11, a preferred arrangement relationship between the heads 4, 5, and 6 on the carriage and the sub-tanks that supply ink or treatment liquid to them is illustrated. Figure 16 is a plan view showing a carriage 3J equipped with a head arrangement according to Example 11 and the sub-tank arrangement. The carriage 3J is equipped with an ink head 4 having first to sixth ink heads 4A to 4F, one pre-treatment head 5, and a post-treatment head 6 having first and second post-treatment heads 6A and 6B. The arrangement of these heads is the same as that shown in Figure 13 and elsewhere.

[0122] The carriage 3J 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 head 4A1 of the first ink head 4A from the first tank 7A1 of the ink subtank 7A, and the downstream 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.

[0123] 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 that the ink heads 4 that eject the same ink are arranged close together in the main scanning direction S. 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.

[0124] 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 first and second post-processing heads 6A and 6B, respectively, via a pipe P3.

[0125] The ink subtanks 7A to 7F are mounted on the carriage 3J 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.

[0126] The liquid in the sub-tank 7, which is mounted on the carriage 3J 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.

[0127] However, according to the configuration of Example 11, the ink sub-tanks 7A to 7F are mounted on the carriage 3J so as to be aligned in the main scanning direction S, similar to 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 3J.

[0128] Furthermore, 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. This allows for smaller positional differences 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. 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 them 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 them less susceptible to the effects of the acceleration.

[0129] 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.

[0130] Summary of this disclosure An inkjet recording device according to one aspect of the present disclosure comprises a transport unit that transports a recording medium in a predetermined transport direction, a carriage that moves back and forth in a main scanning direction that intersects the transport direction, a plurality of ink heads that are mounted on the carriage so as to be aligned in the main scanning direction and that eject ink for image formation, and a plurality of processing heads that are mounted on the carriage and that eject non-color-forming processing liquid, wherein the plurality of processing heads are arranged side by side in the main scanning direction at positions different from the ink heads in the transport direction.

[0131] According to this inkjet recording device, the processing head is positioned at a different position from the ink head in the transport direction, ensuring the desired landing order of the treatment liquid and ink on the recording medium during both forward and backward movement of the carriage. If the processing head and the ink head were configured to be positioned at the same position in the transport direction, ensuring the desired landing order would require the processing heads to be positioned on both sides of the ink head group. This would increase the width of the carriage in the main scanning direction. According to the configuration disclosed herein, this arrangement is unnecessary, allowing the width of the carriage in the main scanning direction to be reduced. Furthermore, multiple processing heads are positioned side by side in the main scanning direction. Therefore, even if a single processing head is unable to eject an adequate amount of treatment liquid, the necessary amount can be ensured by arranging multiple processing heads.

[0132] In the inkjet recording apparatus, the plurality of ink heads may also be arranged in a direction intersecting the arrangement direction of the plurality of processing heads.

[0133] In this inkjet recording device, multiple ink heads are also arranged in a direction intersecting the arrangement direction of the multiple processing heads (main scanning direction), which makes it possible to reduce the width of the carriage in the main scanning direction even if the number of ink heads is increased to increase the amount of ink ejected or to achieve multi-color printing.

[0134] In the inkjet recording apparatus, the plurality of processing heads may be arranged within a range of an arrangement width of the plurality of ink heads in the main scanning direction.

[0135] According to this inkjet recording apparatus, even when the processing head is mounted on a carriage, it is not necessary to increase the width of the carriage in the main scanning direction, and therefore the width of the carriage in the main scanning direction can be reduced.

[0136] In the inkjet recording apparatus, the processing head may be arranged so that a portion of the processing head is located between a pair of ink heads adjacent to each other in the main scanning direction.

[0137] This inkjet recording device allows the ink heads and processing heads, which are arranged at different positions in the transport direction (sub-scanning direction), to be densely arranged in the transport direction, thereby reducing the width of the carriage in the transport direction.

[0138] In the inkjet recording device described above, the processing head may include a plurality of same-color ink heads that eject ink of the same color and are arranged so that a portion of the processing head is adjacent to the ink head in the main scanning direction and the transport direction, and when each of the same-color ink heads counts the number of adjacent processing heads, the difference between the maximum and minimum counts may be 1 or less.

[0139] Generally, heads that eject liquid using a jet method generate heat because they use electricity to pressurize the liquid. In particular, unlike ink heads that only eject dots of the required colors, processing heads that must eject dots of all colors are more likely to become hot. Ink heads adjacent to such processing heads are also more likely to become hot, resulting in differences in the amount of ink ejected compared to ink heads not adjacent to the processing head. As described above, by setting the difference between the maximum and minimum counts of ink heads of the same color adjacent to the processing head to 1 or less, significant differences in the amount of ink ejected are less likely to occur between multiple ink heads of the same color.

[0140] In the inkjet recording device described above, the processing head is arranged so that a portion thereof is adjacent to the ink head in the main scanning direction and the transport direction, and the plurality of ink heads include at least a first ink head that ejects ink of a first color and a second ink head that ejects ink of a second color, and when the number of adjacent processing heads of the first ink head is greater than the number of adjacent processing heads of the second ink head, the first ink head may be configured to eject ink that has a smaller change in viscosity with temperature than the second color ink.

[0141] In this inkjet recording device, the first ink head, which has a larger number of adjacent processing heads, ejects ink with a small change in viscosity due to temperature. Therefore, even if the first ink head is heated by the processing head, the temperature change in the ejection volume and ejection speed of the first color ink can be small.

[0142] In the inkjet recording apparatus, the plurality of processing heads and the plurality of ink heads may be arranged separately in the main scanning direction.

[0143] When the ink and the treatment liquid come into contact, for example, aggregation of ink components may occur. In this case, if the aggregate adheres to the ink ejection nozzles of the ink head, ejection defects may occur. According to the inkjet recording device described above, the treatment head and the ink head are arranged separately in the main scanning direction, so that contact between the ink and the treatment liquid on the carriage can be made less likely.

[0144] The inkjet recording device may include a pre-processing head arranged upstream of the ink head in the transport direction and a post-processing head arranged downstream, and at least one of the pre-processing head and the post-processing head may be arranged in line in the main scanning direction.

[0145] According to this aspect, it is possible to provide an all-in-one inkjet recording device in which all of the ejection heads for the pretreatment liquid, ink, and posttreatment liquid are mounted on a single carriage. Furthermore, because the pretreatment head, ink head, and posttreatment head are sequentially arranged in the transport direction, it is possible to ensure a desirable landing order of the pretreatment liquid, ink, and posttreatment liquid onto the recording medium. Furthermore, because at least one of the pretreatment head and the posttreatment head is arranged side by side in the main scanning direction, it is possible to ensure the required ejection amounts of the pretreatment liquid and posttreatment liquid.

[0146] In the inkjet recording device described above, the carriage may include a first region in which the plurality of ink heads are arranged and a second region adjacent to the first region in the main scanning direction, and the pre-treatment head and the post-treatment head may be arranged in the second region.

[0147] According to this inkjet recording device, the pre-treatment head, the post-treatment head, and the ink head can be arranged separately in the main scanning direction, which makes it possible to prevent the pre-treatment liquid, the post-treatment liquid, and the ink from coming into contact with each other on the carriage, and to reduce the occurrence of problems such as aggregation.

[0148] In the inkjet recording apparatus, the pre-treatment head and the post-treatment head may be arranged in a central region of the arrangement width of the plurality of ink heads in the main scanning direction.

[0149] Alternatively, the pre-processing heads and the post-processing heads may be arranged so that the center of arrangement or alignment of one or more of the pre-processing heads in the main scanning direction coincides with the center of arrangement or alignment of one or more of the post-processing heads in the main scanning direction.

[0150] These inkjet recording devices can reduce the variation in the time from when the pre-treatment liquid lands on the recording medium until the ink lands, as well as the variation in the time from when the ink lands on the recording medium until the post-treatment liquid lands, at each main scanning position.

[0151] In the inkjet recording device described above, when the larger number of heads out of the pre-processing heads and the post-processing heads is m and the smaller number of heads is n, the requirement that m = n + odd number is satisfied, the center of arrangement or alignment of one or more of the pre-processing heads in the main scanning direction and the center of arrangement or alignment of one or more of the post-processing heads may coincide in the main scanning direction, and the center of arrangement or alignment of the pre-processing head and the post-processing head may coincide in the main scanning direction with the arrangement position of one of the plurality of ink heads.

[0152] According to this inkjet recording device, the pre-treatment head and the post-treatment head can be mounted on the carriage in a relatively compact state. This makes it possible to reduce the number of ink heads located close to the treatment head among the multiple ink heads. This reduces the possibility of contact between the pre-treatment liquid and the post-treatment liquid and the ink on the carriage.

[0153] The inkjet recording device may further include 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 including an engagement portion that is held in a cantilevered state by the holding member, and the pre-processing head may be positioned closer to the engagement portion than the post-processing head in the transport direction.

[0154] According to this inkjet recording device, the carriage can be supported with a simple structure by cantilevering it on a holding member. Furthermore, cantilevering makes it easy to open one side of the carriage, facilitating maintenance of the ink head and processing head. When the carriage is cantilevered, it is expected that the height accuracy will decrease on the side of the carriage farther from the engagement portion. However, since the post-processing head, which has a relatively high tolerance for ejection accuracy, is mounted on the side farther from the engagement portion, this is unlikely to have a significant impact on image quality.

[0155] The inkjet recording device may further include 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 including an engagement portion that is held in a cantilevered state by the holding member, and the one of the pre-processing heads and the post-processing heads that has fewer heads may be arranged on the engagement portion side of the carriage.

[0156] As described above, the processing head generates heat during the ejection operation. This heats up the carriage carrying the processing head, potentially causing thermal deformation of the carriage and its supporting structure. In a configuration in which the carriage is supported by a cantilever, this thermal deformation can affect the accuracy of ink droplet placement. The above configuration reduces the number of processing heads arranged on the base end side, thereby minimizing the impact of thermal deformation.

[0157] The inkjet recording device may further include 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 including an engagement portion that is held in a cantilevered state by the holding member, and the head of the ink head and the processing head that is arranged closest to the engagement portion of the carriage may be arranged at a position excluding the end of the array of ink heads and processing heads in the main scanning direction.

[0158] In this inkjet recording device, the head closest to the engagement portion is not located at the end of the array of ink heads and processing heads in the main scanning direction. Generally, the end of the main scanning direction is closest to the end (corner) of the carriage. Thermal deformation at the end of the carriage near the base end reduces the positional accuracy of the heads mounted on the carriage. This configuration makes it less likely for such problems to occur.

[0159] The inkjet recording device may further include an ink sub-tank that supplies the ink to each of the plurality of ink heads, and a processing liquid sub-tank that supplies the processing liquid to each of the plurality of processing heads, wherein the ink sub-tanks are mounted on the carriage so as to be aligned in the main scanning direction, and the processing liquid sub-tank is arranged next to the ink sub-tank in the main scanning direction at a position different from the ink sub-tank in the transport direction.

[0160] According to the above configuration, the ink subtanks and the processing head subtanks are aligned in the main scanning direction at different positions in the transport direction, just like the heads. This allows the subtanks to be arranged in a relatively narrow area on the carriage. Furthermore, acceleration in the main scanning direction acts on the liquid in the subtanks mounted on the carriage, which moves back and forth in the main scanning direction. The subtanks and the heads are connected by predetermined conduits. However, if the subtanks are widely distributed on the carriage, the conduits' layout area in the main scanning direction also becomes large, increasing the effect of the acceleration, which may cause meniscus damage at the ejection portion of the head. According to the above configuration, the conduits' layout area in the main scanning direction can be relatively narrowed.

[0161] According to the present disclosure described above, it is possible to provide an inkjet recording apparatus that can ensure the necessary ejection amounts of ink and treatment liquid while miniaturizing the carriage. [Explanation of symbols]

[0162] 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~3J carriage 31 Head support frame 32 Back frame (engagement part) 4 ink heads 4A~4F 1st~6th ink heads 4A1~4F1 Upstream head 4A2~4F2 Downstream head 5 Pre-processing head (processing head) 6 Post-processing head (processing head) 7 Subtank 7A~7F Ink subtank 71 Sub-tank for pre-treatment liquid 72 Sub-tank for post-processing liquid F Conveying direction S Main scanning direction W work (recording media)

Claims

1. A plurality of ink heads arranged in a main scanning direction intersecting the transport direction of the recording medium, which eject ink for image formation, Multiple processing heads, including multiple post-processing heads that discharge a non-coloring post-processing solution, Equipped with, The plurality of post-processing heads are arranged in the main scanning direction at positions different from the ink heads in the transport direction, An inkjet recording apparatus in which at least one of the plurality of post-processing heads is positioned such that its upstream portion in the transport direction fits between a pair of adjacent ink heads in the main scanning direction.

2. A plurality of ink heads arranged in a main scanning direction intersecting the transport direction of the recording medium, which eject ink for image formation, Multiple processing heads, including multiple pre-treatment heads that discharge a non-coloring pre-treatment solution, Equipped with, The plurality of pre-processing heads are arranged in the main scanning direction at positions different from the ink heads in the transport direction, An inkjet recording apparatus in which at least one of the plurality of pre-processing heads is positioned such that its downstream portion in the transport direction fits between a pair of adjacent ink heads in the main scanning direction.

3. A plurality of ink heads arranged in a main scanning direction intersecting the transport direction of the recording medium, which eject ink for image formation, A plurality of processing heads, including at least one pre-treatment head that discharges a non-coloring pre-treatment solution, and a plurality of post-treatment heads that discharge a non-coloring post-treatment solution, Equipped with, The plurality of post-processing heads are arranged in the main scanning direction at positions different from the ink heads in the transport direction, The at least one pre-processing head is positioned such that its downstream portion in the transport direction is positioned between a pair of adjacent ink heads in the main scanning direction. An inkjet recording apparatus in which at least one of the plurality of post-processing heads is positioned such that its upstream portion in the transport direction fits between a pair of adjacent ink heads in the main scanning direction.

4. In the inkjet recording apparatus according to any one of claims 1 to 3, An inkjet recording device in which the plurality of ink heads are also arranged in a direction intersecting the arrangement direction of the plurality of processing heads.

5. In the inkjet recording apparatus according to any one of claims 1 to 3, An inkjet recording device in which the plurality of processing heads are arranged within the range of the arrangement width of the plurality of ink heads in the main scanning direction.

6. In the inkjet recording apparatus according to any one of claims 1 to 3, The plurality of processing heads are arranged such that a portion of them are adjacent to the ink head in the main scanning direction and the transport direction. The plurality of ink heads include at least a first ink head that ejects a first color of ink and a second ink head that ejects a second color of ink. An inkjet recording device in which, when the number of adjacent processing heads is greater for the first ink head than for the second ink head, the first ink head ejects an ink that has less viscosity change due to temperature than the second ink.

7. In the inkjet recording apparatus according to claim 3, An inkjet recording apparatus in which the pre-processing head and the post-processing head are located in the central region of the arrangement width of the plurality of ink heads in the main scanning direction.

8. In the inkjet recording apparatus according to claim 3, An inkjet recording apparatus in which the pre-processing heads and the post-processing heads are arranged such that the arrangement or alignment centers of one or more pre-processing heads and the arrangement or alignment centers of one or more post-processing heads coincide in the main scanning direction.

9. In the inkjet recording apparatus according to claim 3, When the number of heads in the larger of the pre-processing heads and the post-processing heads is m and the number of heads in the smaller of the two is n, the requirement m = n + an odd number is satisfied. The arrangement or center of one or more pre-processing heads in the main scanning direction and the arrangement or center of one or more post-processing heads coincide in the main scanning direction, and An inkjet recording apparatus in which the arrangement or center of the pre-processing head and the post-processing head coincides with the arrangement position of one of the plurality of ink heads in the main scanning direction.

10. In the inkjet recording apparatus according to any one of claims 1 to 3, An inkjet recording device in which at least one of the plurality of ink heads is a multicolor head having a plurality of ink ejection areas that eject ink of different colors from each other.

11. In the inkjet recording apparatus according to any one of claims 1 to 3, The system further comprises a carriage that moves back and forth in the main scanning direction, An inkjet recording device in which the plurality of ink heads and the plurality of processing heads are arranged in the carriage.

12. An inkjet recording method using the inkjet recording apparatus described in claim 1, Transporting the recording medium in the transport direction, The process involves moving one of the plurality of ink heads and the plurality of post-processing heads back and forth in the main scanning direction, Discharging the ink from at least one of the plurality of ink heads onto the recording medium, Discharging the post-processing liquid from at least one of the plurality of post-processing heads to the recording medium, An inkjet recording method comprising the following features.

13. An inkjet recording method using the inkjet recording apparatus described in claim 2, Transporting the recording medium in the transport direction, The process involves moving one of the plurality of ink heads and the plurality of pre-processing heads back and forth in the main scanning direction, Discharge the pre-processing liquid onto the recording medium from at least one of the plurality of pre-processing heads, To eject the ink from at least one of the plurality of ink heads to the recording medium, An inkjet recording method comprising the following features.

14. An inkjet recording method using the inkjet recording apparatus described in claim 3, Transporting the recording medium in the transport direction, The plurality of ink heads, at least one pre-processing head, and the plurality of post-processing heads are to be moved back and forth in the main scanning direction. Discharging the pre-treatment liquid from at least one pre-treatment head onto the recording medium, To eject the ink from at least one of the plurality of ink heads to the recording medium, Discharging the post-processing liquid from at least one of the plurality of post-processing heads to the recording medium, An inkjet recording method comprising the following features.

15. A printing method using the inkjet recording apparatus described in claim 1, Transporting the recording medium in the transport direction, The process involves moving one of the plurality of ink heads and the plurality of post-processing heads back and forth in the main scanning direction, To cause the ink to land on a predetermined recording area of ​​the recording medium from at least one of the plurality of ink heads, The post-processing liquid is deposited onto the recording area that has received the ink ejection from at least one of the plurality of post-processing heads. A printing method comprising the following:

16. A printing method using the inkjet recording apparatus described in claim 2, Transporting the recording medium in the transport direction, The process involves moving one of the plurality of ink heads and the plurality of pre-processing heads back and forth in the main scanning direction, The pre-processing liquid is deposited onto a predetermined recording area of ​​the recording medium from at least one of the plurality of pre-processing heads, The ink is to be deposited onto the recording area that has received the discharge of the pre-treatment liquid from at least one of the plurality of ink heads, A printing method comprising the following:

17. A printing method using the inkjet recording apparatus described in claim 3, Transporting the recording medium in the transport direction, The plurality of ink heads, at least one pre-processing head, and the plurality of post-processing heads are to be moved back and forth in the main scanning direction. The pre-processing liquid is deposited onto a predetermined recording area of ​​the recording medium from at least one pre-processing head, The ink is to be deposited onto the recording area that has received the discharge of the pre-treatment liquid from at least one of the plurality of ink heads, The post-processing liquid is deposited onto the recording area that has received the ink ejection from at least one of the plurality of post-processing heads. A printing method comprising the following:

18. The printing method according to any one of claims 15 to 17, wherein the recording medium is fabric.

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