Inkjet recording apparatus and inkjet recording method

Abstract

SOLUTION: An ink-jet recording device comprises: a conveyance unit; a carriage; at least one pre-processing head; at least one ink head; and at least one post-processing head. The conveyance unit conveys a recording medium in a prescribed conveying direction. The carriage reciprocates in a main scanning direction intersecting the conveying direction. The pre-processing head is mounted on the carriage, and discharges a non-color developing pre-processing liquid. At least one ink head is mounted on the carriage, and discharges ink. At least one post-processing head is mounted on the carriage, and discharges a non-color developing post-processing liquid. The at least one pre-processing head, the at least one ink head, and the at least one post-processing head are arranged misaligned from each other in the conveying direction.EFFECT: It makes it possible to hardly cause reduction in image quality.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] 2. Description of the Related Art Inkjet recording devices such as inkjet printers include an ink head that ejects ink for forming an image onto a recording medium.

[0003] When the recording medium is wide, the ink head is mounted on a carriage that moves back and forth in the main scanning direction. During recording, 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 (colored ink) is ejected from the ink head.

[0004] Patent Document 1 discloses a technique in which a pretreatment liquid is applied to a recording medium before ejecting colored ink onto the recording medium, and a posttreatment liquid is applied to the recording medium after ejecting the colored ink onto the recording medium. The pretreatment liquid is a treatment liquid that improves, for example, the fixability of the ink to the recording medium and the coagulation of the ink pigment. The posttreatment liquid is a treatment liquid that improves, for example, the robustness of a printed image. The carriage of the inkjet recording device is equipped with, in addition to the ink head, a pretreatment head that ejects the pretreatment liquid and a posttreatment head that ejects the posttreatment liquid. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-094673 Summary of the Invention

[0006] An inkjet recording apparatus according to one aspect of the present disclosure includes a transport unit, a carriage, at least one pre-treatment head, at least one ink head, and at least one post-treatment head. The transport unit transports a recording medium in a predetermined transport direction. The carriage moves back and forth along a main scanning direction intersecting the transport direction. The at least one pre-treatment head is mounted on the carriage and ejects a non-color-forming pre-treatment liquid. The at least one ink head is mounted on the carriage and ejects ink. The at least one post-treatment head is mounted on the carriage and ejects a non-color-forming post-treatment liquid. The at least one pre-treatment head, the at least one ink head, and the at least one post-treatment head are arranged offset from one another in the transport direction. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view showing the overall configuration of an inkjet recording apparatus 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 a serial printing method employed in one embodiment of the present disclosure. [Figure 5A] FIG. 5A is a schematic diagram showing the printing status during the forward and backward travel of the carriage. [Figure 5B] FIG. 5B is a schematic diagram showing the printing status during the forward and backward travel of the carriage. [Figure 6] FIG. 6 is a plan view schematically showing the arrangement of the ink heads and processing heads on the carriage shown in FIG. [Figure 7] FIG. 7 is a block diagram of an inkjet recording apparatus according to an embodiment of the present disclosure. [Figure 8] FIG. 8 is a plan view showing the relationship between the pretreatment liquid landing area and the ink landing area on the recording medium in an inkjet recording apparatus according to an embodiment of the present disclosure. [Figure 9] FIG. 9 is a plan view showing the relationship between the pretreatment liquid landing area and the ink landing area on the recording medium in an inkjet recording apparatus according to an embodiment of the present disclosure. [Figure 10] FIG. 10 is a schematic diagram showing how ink lands on the surface of a recording medium as the carriage moves. DETAILED DESCRIPTION OF THE INVENTION

[0008] Inkjet recording apparatuses according to embodiments of the present disclosure will be described below with reference to the drawings. In these embodiments, an inkjet printer equipped with an ink head that ejects ink for forming an image onto a wide, long recording medium will be exemplified as a specific example of an inkjet recording apparatus. Inkjet printers are suitable for digital textile printing, which uses an inkjet method to print images such as letters and patterns onto a recording medium made of fabric such as woven or knitted fabric. Of course, the inkjet recording apparatus according to the present disclosure can also be used to print various inkjet images on recording media such as paper sheets and resin sheets.

[0009] [Overall configuration of inkjet printer] Fig. 1 is a perspective view showing the overall configuration of an inkjet printer 1 according to a first embodiment of the present disclosure, and Fig. 2 is a schematic cross-sectional view taken along line II-II in Fig. 1. The inkjet printer 1 is a printer that prints images on a wide and long workpiece W (recording medium) using an inkjet method, and includes a device frame 10, and a workpiece transport unit 20 (transport unit) and carriage 3 that are incorporated into this device frame 10. In this embodiment, the left-to-right direction is the main scanning direction S (Fig. 3) when printing on the workpiece W, and the direction from rear to front is the sub-scanning direction (direction F for transporting the workpiece W).

[0010] The device frame 10 forms a framework for mounting various components of the inkjet printer 1. The work transport unit 20 is a mechanism that intermittently feeds (transports) the work W so that the work W passes through a printing area (image formation position) where inkjet printing processing is performed in a transport direction F from rear to front. The carriage 3 is equipped with an ink head 4, a pre-processing head 5, a post-processing head 6, and a sub-tank 7, and moves back and forth in a main scanning direction S (left and right direction) that intersects with the transport direction F of the work W during the inkjet printing processing.

[0011] 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.

[0012] The right frame 112 forms the maintenance area 13. The maintenance area 13 is an area where the carriage 3 is retracted when the printing process is not being performed. In the maintenance area 13, cleaning processes, purging processes, etc. are performed on the nozzles (ejection holes) of the ink head 4, pre-processing head 5, and post-processing head 6, and caps are fitted. The left frame 113 forms the return area 14 for the carriage 3. The return area 14 is an area where the carriage 3 temporarily enters when it performs a main scan in the opposite direction after performing a main scan in the opposite direction across the printing area 12 from right to left during the printing process.

[0013] A carriage guide 15 is attached to the upper side of the device frame 10 to allow the carriage 3 to reciprocate in the left-right direction. The carriage guide 15 is a flat, plate-shaped member that is long in the left-right direction, and is disposed above the work transport unit 20. A timing belt 16 (moving member) is attached to the carriage guide 15 so as to be able to move in a circular motion in the left-right direction (main scanning direction). The timing belt 16 is an endless belt, and is driven by a carriage drive unit 3S, which will be described later, to move in a circular motion in the left or right direction.

[0014] The carriage guide 15 is equipped with a pair of upper and lower guide rails 17 (holding members) that extend parallel to the left and right and that hold the carriage 3 in a state that allows it to move back and forth in the main scanning direction S. The carriage 3 is engaged with the guide rails 17. The carriage 3 is also fixed to a timing belt 16. As the timing belt 16 moves orbitally left or right, the carriage 3 moves left or right along the carriage guide 15 while being guided by the guide rails 17.

[0015] 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.

[0016] 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.

[0017] 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) at a predetermined transport pitch so that the workpiece W passes through the printing area 12 (image forming position) facing the carriage 3. The pinch roller 26 is disposed opposite the transport roller 25 from above, and forms a transport nip portion with the transport roller 25.

[0018] 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.

[0019] The carriage 3 is supported at one end by a guide rail 17 and moves back and forth in a main scanning direction S (left and right in this embodiment) that intersects (orthogonal in this embodiment) with the transport direction F in the printing area (image forming position). 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).

[0020] The head support frame 31 is a horizontal plate that holds the heads 4 to 6. The back frame 32 is a vertical plate that extends upward from the rear end edge of the head support frame 31. As described above, the timing belt 16 is fixed to the back frame 32. The guide rail 17 is engaged with the back frame 32. That is, in this embodiment, the back frame 32 is an engagement portion that is held in a cantilevered state by the guide rail 17. The head support frame 31 is a horizontal plate whose rear end side is supported in a cantilevered state by the guide rail 17 by the engagement portion.

[0021] The cantilevered state refers to a state in which the engagement portion (back frame 32) of the carriage 3 is located only on one side, either upstream or downstream from the center of the carriage 3 in the transport direction F, and no other engagement portion is located on the opposite side of the side where the engagement portion is located. The engagement portion is a portion that is held by the guide rail 17, which is a holding member. The engagement portion may also be located outside the range in which the ink head 4 and processing head are located in the transport direction F. In other words, the engagement portion may be located only on the upstream side or only on the downstream side of the range in which the ink head 4 and processing head are located in the transport direction F.

[0022] [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.

[0023] 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. Note that the ink may contain a dye instead of a pigment. Therefore, hereinafter, the concept of both pigment and dye may be referred to as a colorant. In this embodiment, the multiple 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 ink, the second ink head 4B ejects green ink, the third ink head 4C ejects yellow ink, the fourth ink head 4D ejects red ink, the fifth ink head 4E ejects blue ink, and the sixth ink head 4F ejects black ink.

[0024] 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 one head.

[0025] The pre-treatment head 5 and post-treatment head 6 are disposed at different positions from the ink heads 4 in the transport direction F. The pre-treatment head 5 is disposed upstream of the ink heads 4 in the transport direction F. FIG. 3 shows an example in which one pre-treatment head 5 is disposed near the right end of the array of ink heads 4. Similarly, the post-treatment head 6 is disposed downstream of the ink heads 4 in the transport direction F. FIG. 3 shows an example in which one post-treatment head 6 is disposed at the right end of the array of ink heads 4. In other embodiments, multiple pre-treatment heads 5 or multiple post-treatment heads 6 may be disposed. That is, the carriage 3 is equipped with at least one pre-treatment head 5 and at least one post-treatment head 6.

[0026] The pretreatment head 5 ejects a pretreatment liquid to perform a predetermined pretreatment on the workpiece W. The pretreatment liquid is ejected from the ink head 4 onto a position on the workpiece W to which ink has not yet been ejected from the ink head 4. The pretreatment liquid is a non-color-forming treatment liquid that does not develop color even when it adheres to the workpiece W, and is a treatment liquid that exhibits functions such as increasing the fixation of ink to the workpiece W or the coagulation of ink pigments (dyes). 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. Note that the post-treatment liquid and the pre-treatment liquid are different treatment liquids. Specifically, the components contained in the post-treatment liquid and the pre-treatment liquid are different.

[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 portions where no color is to be printed, i.e., portions where no ink is ejected, the pretreatment liquid and the posttreatment liquid are basically not ejected either. Note that, in order to adjust the image quality of the image to be printed and the texture of the workpiece W, the selection of ejection of the pretreatment liquid and the posttreatment liquid may be made to differ from the ejection of the ink.

[0031] An opening 31H (Fig. 3) is provided at the location where each head is arranged on 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 their 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 conduits (not shown in FIG. 3).

[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, pre-treatment head 5, and post-treatment head 6 - are mounted on a single carriage 3. With this inkjet printer 1, for example, in the printing process of inkjet printing onto fabric in digital textile printing, the process of ejecting the pre-treatment liquid and the process of ejecting the post-treatment liquid can be carried out in an integrated manner. This makes it possible to simplify the textile printing process and make the textile printing device more compact.

[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 intermittently feeds the workpiece W in the transport direction F, repeatedly. Here, the ink heads 4 are assumed to have a predetermined printing width Pw in the transport direction F. The printing width Pw is approximately equal to the arrangement range of the ink ejection nozzles of the ink heads 4. Note that in Figure 4 and Figures 5A and 5B described below, the width of each head in the transport direction F and the printing width Pw are depicted as approximately equal. 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.

[0036] FIG. 4 shows the state in which the carriage 3 moves in the forward direction SA in the main scanning direction S and has completed printing of a strip-shaped image G1 with a printing width Pw. During this main scanning in the forward direction SA, the feeding of the workpiece W is stopped. After printing the strip-shaped image G1, the workpiece W is sent out in the transport direction F by a pitch corresponding to the printing width Pw. At this time, the carriage 3 waits in the return area 14 on the left end side. After sending out the workpiece W, the carriage 3 returns in the return direction SB as the timing belt 16 moves in the reverse direction. The workpiece W is in a stationary state. Then, as shown in FIG. 4, the carriage 3 moves in the return direction SB and prints a strip-shaped image G2 with a printing width Pw upstream of the strip-shaped image G1. Similar operations are repeated thereafter.

[0037] 5A and 5B are schematic diagrams showing the printing status of the carriage 3 on its forward and return passes. The ink head 4, pre-treatment head 5, and post-treatment head 6 mounted on the carriage 3 are shown in simplified form. The ink head 4 includes first, second, third, and fourth ink heads 4A, 4B, 4C, and 4D for ejecting ink of different colors (first, second, third, and fourth), respectively. These first to fourth ink heads 4A to 4D are aligned in a line in the main scanning direction S. The pre-treatment head 5 is located upstream of the ink head 4 in the transport direction F, and the post-treatment head 6 is located downstream. As with the case described with reference to FIG. 4, the workpiece W is sent in the transport direction F between the printing on the forward pass and the printing on the return pass. The distance traveled in the transport direction F is the spacing pitch (head pitch) between adjacent heads in the transport direction F. This distance also corresponds to the printing width Pw of each head 4, 5, and 6.

[0038] 5A shows a state in which the carriage 3 is performing a printing operation (outgoing main scanning) while moving in the outgoing direction SA in the main scanning direction S. Area A4 on the workpiece W is an area that faces the pretreatment head 5 mounted on the most upstream side of the carriage 3. During this outgoing main scanning, a pretreatment layer Lpre is formed on area A4 by the pretreatment liquid ejected from the pretreatment head 5.

[0039] Region A3 is one head pitch downstream of region A4 and faces the ink head 4. A pre-treatment layer Lpre has already been formed on region A3 over the entire length in the main scanning direction by the previous backward main scanning. During this forward main scanning, first, second, third, and fourth ink layers LCA, LCB, LCC, and LCD are formed on the pre-treatment layer Lpre in region A3 by the first to fourth color inks ejected sequentially in the aligned order of the first to fourth ink heads 4A to 4D. Note that, for ease of understanding, FIG. 5A illustrates the fourth to first ink layers LCD to LCA as if they were stacked sequentially, but they are not actually stacked. Note that the pre-treatment layer Lpre described above and the post-treatment layer Lpos described below are not formed on the workpiece W either.

[0040] Region A2 is one head pitch downstream of region A3 and faces the post-processing head 6 mounted on the most downstream side of the carriage 3. A pre-processing layer Lpre formed by the previous outgoing main scan and first to fourth ink layers LCA to LCD formed by the previous homeward main scan have already been formed in region A2 over the entire length in the main scanning direction. During this outgoing main scan, a post-processing layer Lpos is formed on the first to fourth ink layers LCA to LCD in region A2 by the post-processing liquid ejected from the post-processing head 6.

[0041] Region A1 is one head pitch downstream of region A2, and is an area where the carriage 3 has passed and printing has been completed. That is, in region A1, a pre-treatment layer Lpre, first to fourth ink layers LCA to LCD, and a post-treatment layer Lpos are formed over the entire length in the main scanning direction.

[0042] 5B shows the state in which, after completing the outward main scan in FIG. 5A, the carriage 3 turns around and moves in the return direction SB while performing the return main scan. Before the return movement, the workpiece W is sent out one head pitch in the transport direction F. Area A5 on the workpiece W is one head pitch upstream of area A4, and is the area that the pretreatment head 5 faces during this return main scan. A pretreatment layer Lpre is formed on area A5 by the pretreatment liquid ejected from the pretreatment head 5.

[0043] 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.

[0044] The reason why printing is possible in both the forward main scan and the backward main scan as described above is because the pre-treatment head 5 and the post-treatment head 6 are shifted in the transport direction F relative to the ink head 4. If the pre-treatment head 5, ink head 4, and post-treatment head 6 were aligned in this order in the main scan direction S on the carriage 3, printing that ensures the pre-treatment liquid and post-treatment liquid land in the desired order could only be achieved in either the forward or backward main scan. To enable bidirectional printing, pairs of the pre-treatment head 5 and the post-treatment head 6 would have to be arranged on both sides of the ink head 4 array. In this case, the width of the carriage 3 in the main scan direction S would increase. This arrangement is unnecessary in this embodiment, so the width of the carriage 3 in the main scan direction S can be reduced.

[0045] If there are multiple rows of ink heads 4, it is possible to increase the amount of ink that lands on the workpiece W. For example, if there are two rows of ink heads 4, printing can be performed as follows. After the first row of ink heads 4 forms the first to fourth ink layers LCA to LCD as described above, the workpiece W is transported in the transport direction F by one head pitch, and the second row of ink heads 4 forms the first to fourth ink layers LCA to LCD. In this way, it is possible to print two layers' worth of ink on the workpiece W.

[0046] FIG. 6 is a plan view showing a schematic arrangement of heads on the carriage 3 according to this embodiment, and also shows 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 carriage 3 is equipped with first to sixth ink heads 4A to 4F, pre-processing head 5, and post-processing head 6, each of which ejects six different colors of ink. Each color has one ink head 4A to 4F, one pre-processing head 5, and one post-processing head 6. The group of first to sixth ink heads 4A to 4F that make up the ink head 4 is aligned in the main scanning direction S in the central region of the carriage 3 in the transport direction F. Furthermore, when viewed along the main scanning direction S, the downstream end of the pre-processing head 5 in the transport direction F is positioned to overlap the upstream end of the ink head 4 in the transport direction F. Similarly, when viewed along the main scanning direction S, the downstream end of the ink head 4 in the transport direction F is arranged to overlap the upstream end of the post-treatment head 6 in the transport direction F.

[0047] Unless otherwise specified, in each of the figures including Figure 6, the distance between adjacent heads in the main scanning direction S (the distance between the centers of the heads) is the same. Similarly, the distance between adjacent heads in the transport direction F (the distance between the centers of the heads) is the same.

[0048] In Figure 6, the nozzle region located on the underside of each head is shown schematically by a dashed line inside the external shape of each head. The nozzle region is an area defined by the nozzles located on the underside of each head that eject liquid during printing. In each head, multiple nozzles are formed in the nozzle region, aligned along the main scanning direction S and the transport direction F.

[0049] The upstream and downstream ends of the nozzle regions of the first ink head 4A to the sixth ink head 4F in the transport direction F are located at the same position as one another in the transport direction F. Furthermore, the upstream ends of the nozzle regions of the first ink head 4A to the sixth ink head 4F in the transport direction F are located contiguous to (in contact with, adjacent to) the downstream end of the nozzle region of the pre-treatment head 5 in the transport direction F. Furthermore, the upstream end of the nozzle region of the post-treatment head 6 in the transport direction F is located contiguous to the downstream end of the nozzle regions of the first ink head 4A to the sixth ink head 4F in the transport direction F.

[0050] The nozzle arrangement area is arranged so that the ink and each treatment liquid land adjacent to each other in units of resolution. Therefore, the landing area of ​​the pre-treatment liquid and the landing area of ​​the ink of the first ink head 4A to the sixth ink head 4F are continuous (adjacent) at the pre-treatment / ink head boundary line L1, and the landing area of ​​the ink of the nozzle area of ​​the first ink head 4A to the sixth ink head 4F and the landing area of ​​the post-treatment liquid are continuous at the ink / post-treatment head boundary line L2.

[0051] FIG. 7 is a block diagram of an inkjet printer 1 according to this embodiment. The inkjet printer 1 further includes a control unit 90 that controls the overall operation of each unit of the inkjet printer 1, a carriage driver 3S, an I / F 91, and an image memory 92. The control unit 90 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores control programs, a RAM (Random Access Memory) used as a work area for the CPU, and other components. The control unit 90 is electrically connected to the first motor M1, the second motor M2, the ink head 4, the pre-processing head 5, and the post-processing head 6, as well as the carriage driver 3S, the I / F 91, and the image memory 92. The carriage driver 3S includes a motor (not shown) that rotates a timing belt 16 to reciprocate the carriage 3 along the main scanning direction S.

[0052] The image memory 92 temporarily stores print image data provided from an external device such as a personal computer.

[0053] The I / F 91 is an interface circuit for realizing data communication with external devices, and for example creates communication signals that comply with the communication protocol of the network that connects the inkjet printer 1 to the external device, and converts communication signals from the network into data in a format that can be processed by the inkjet printer 1. A print instruction signal sent from a personal computer or the like is given to the control unit 90 via the I / F 91, and image data is stored in the image memory 92 via the I / F 91.

[0054] The control unit 90 functions as including a drive control unit 901, a discharge control unit 902, a discharge pattern designation unit 903, and a storage unit 904 by the CPU executing a control program stored in the ROM.

[0055] The drive control unit 901 controls the first motor M1 and the second motor M2 of the work transport unit 20, thereby controlling the transport operation of the workpiece W. The drive control unit 901 also controls the carriage drive unit 3S, thereby controlling the reciprocating movement of the carriage 3 along the main scanning direction S.

[0056] The ejection control unit 902 inputs predetermined command signals to the ink head 4, the pre-treatment head 5, and the post-treatment head 6, and controls the ejection operations of the inks of each color, the pre-treatment liquid, and the post-treatment liquid.

[0057] The ejection pattern designation unit 903 designates an ejection pattern for each head in order to cause ink to land at a predetermined position on the workpiece W, according to image information received from the I / F 91 or the image memory 92. More specifically, the ejection pattern designation unit 903 designates the ink ejection amount (ejection pattern) for the ink head 4 of each color, and inputs signals corresponding to the ejection amount and the ejection timing to the ejection control unit 902. The ejection pattern designation unit 903 also performs the same control as above for the pre-treatment head 5 that ejects the pre-treatment liquid and the post-treatment head 6 that ejects the post-treatment liquid.

[0058] The storage unit 904 stores in advance various thresholds, parameters, etc. that are referenced by the drive control unit 901, the discharge control unit 902, and the discharge pattern designation unit 903 of the control unit 90.

[0059] The structure of the control unit 90 is not limited to the above-described embodiment, and may be different from the above-described embodiment depending on the structure of the device and program, etc. In other words, the functions of the drive control unit 901, the discharge control unit 902, the discharge pattern designation unit 903, and the storage unit 904 can be said to be executed by the control unit 90.

[0060] <About the ejection of each treatment liquid and ink> 6, in the head arrangement in this embodiment, one pre-treatment head 5 is arranged upstream of the ink head 4 in the transport direction F, and one post-treatment head 6 is arranged downstream. In other words, it is possible to provide an all-in-one inkjet printer 1 in which three types of heads, namely heads for ejecting pre-treatment liquid, ink, and post-treatment liquid, are mounted on a single carriage 3. Furthermore, because the pre-treatment head 5, ink head 4, and post-treatment head 6 are arranged sequentially in the transport direction F, the pre-treatment liquid, ink, and post-treatment liquid can be ejected in a desired landing order in both the forward main scan and the backward main scan.

[0061] As described above, in this embodiment, the inkjet printer 1 includes a work transport unit 20 that transports the work W in a predetermined transport direction F, a carriage 3 that moves back and forth along a main scanning direction S that intersects with the transport direction F, a pre-treatment head 5 that is mounted on the carriage 3 and ejects a non-color-forming pre-treatment liquid, an ink head 4 that is mounted on the carriage 3 and ejects ink, and a post-treatment head 6 that is mounted on the carriage 3 and ejects a non-color-forming post-treatment liquid. When the ejection control unit 902 controls the ejection of each head in accordance with the movement of the carriage 3 in the main scanning direction S, the pre-treatment head 5 ejects pre-treatment liquid onto a predetermined recording area (pixel) on the workpiece W in accordance with the first movement of the carriage 3 along the main scanning direction S, and then the workpiece transport unit 20 transports the workpiece W at a predetermined pitch in the transport direction F ( FIG. 6 ). Furthermore, the ink head 4 ejects ink onto the recording area in accordance with the second movement of the carriage 3 along the main scanning direction S, and then the workpiece transport unit 20 further transports the workpiece W in the transport direction F. Then, the post-treatment head 6 ejects post-treatment liquid onto the recording area in accordance with the third movement of the carriage 3 along the main scanning direction S, thereby forming an ink image containing the pre-treatment liquid, ink, and post-treatment liquid on the recording area. For this reason, in this embodiment, the pre-treatment head 5, ink head 4, and post-treatment head 6 are arranged offset from each other in the transport direction F ( FIG. 6 ). Therefore, the pre-treatment liquid, ink, and post-treatment liquid can be reliably and stably applied to the workpiece W in this order. As a result, it is possible to reliably achieve high-quality printing on the workpiece W. As an example, the first movement of the carriage 3 is in one direction in the main scanning direction S (from right to left in FIG. 6), the second movement is in the other direction in the main scanning direction S (from left to right in FIG. 6), and the third movement is in the one direction in the main scanning direction S.

[0062] That is, in this embodiment, the movement of the carriage 3 when the pre-treatment head 5 moves along the main scanning direction S to eject pre-treatment liquid onto a predetermined area on the workpiece W is defined as a first scan, the movement of the carriage 3 when the ink head 4 moves along the main scanning direction S to eject ink onto the predetermined area is defined as a second scan, and the movement of the carriage 3 when the post-treatment head 6 moves along the main scanning direction S to eject post-treatment liquid onto the predetermined area is defined as a third scan. The first scan, the second scan, and the third scan are different from one another, and the first scan, the second scan, and the third scan are each performed at least once in this order. As a result, the pre-treatment liquid, ink, and post-treatment liquid can be more reliably applied to the workpiece W in this order. Note that the predetermined area on the workpiece W is an area equal to or smaller than the area printed in one scan.

[0063] The present disclosure is not limited to an embodiment in which a single row of ink heads 4 is arranged along the main scanning direction S, as in this embodiment, but may also be an embodiment in which two or more rows of ink heads 4 are arranged in the transport direction F, with each row of ink heads 4 arranged along the main scanning direction S. Furthermore, the ink heads 4 are not limited to those that form images of multiple colors, but a single ink head 4 that ejects ink of a single color may be mounted on the carriage 3. In this case, too, it is sufficient that the pre-treatment head 5, ink heads 4, and post-treatment head 6 are arranged in this order, offset from one another in the transport direction.

[0064] Furthermore, in this embodiment, the carriage 3 has a back frame 32 (engagement portion) that is held in a cantilevered state by a guide rail 17 (holding member). By supporting the carriage 3 in a cantilevered manner on the timing belt 16, the structure can be simplified. Also, by supporting the carriage 3 in a cantilevered manner, the downstream side of the carriage 3 can be easily opened, making it easier to perform maintenance on the ink head 4 and the processing heads 5 and 6.

[0065] 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 closer to the back frame 32 fixed to the timing belt 16, it is expected that the positional accuracy will decrease on the free end, the tip end side 312. 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.

[0066] <Challenges in carriage scanning> FIG. 10 is a schematic diagram showing the ink 4M landing on the surface of the workpiece W as the carriage 3 moves. When the workpiece W is made of fabric, such as woven or knitted fabric, or paper made of paper fibers, its surface has various irregularities. In the case of fabric, surface undulations occur due to the weaving or knitting process, and irregularities exist between adjacent threads depending on the thickness and twist of the threads. These irregularities are generally larger than the ink dot diameter, which is on the order of several tens of microns, and even if they are not, they are of a size that cannot be ignored relative to the ink dot diameter. Furthermore, in the case of paper, minute irregularities exist due to the random distribution of paper fibers on the surface, and depending on the type of paper, the irregularities can be of a size that cannot be ignored relative to the ink dot diameter. In other words, recording media such as fabrics and certain types of paper may have irregularities on their surfaces with a periodicity that cannot be ignored relative to the diameter of the ink dots to be ejected.

[0067] In FIG. 10, when the ink head 4 ejects ink 4M while moving in the main scanning direction S1 from right to left on the paper surface due to the movement of a carriage (not shown), the movement speed of the ink head 4 and the ejection speed of the ink 4M combine to cause each ink droplet 4M to land on the workpiece W at an angle along the direction indicated by the arrow in FIG. 10. In this case, if the workpiece W has an uneven shape with alternating inclined first and second surfaces K1 and K2, as shown in FIG. 10, the amount of ink 4M that lands (applied amount) per unit area on the first surface K1, which is nearly parallel to the ejection direction of the ink 4M, is relatively small, while the amount of ink 4M that lands per unit area on the second surface K2, which is nearly perpendicular to the ejection direction of the ink 4M, is relatively large. This phenomenon occurs because the area on which the same amount of ink 4M lands is larger on the first surface K1 than on the second surface K2.

[0068] Furthermore, when the pretreatment head 5 ejects the pretreatment liquid while moving in the main scanning direction S1 in Fig. 10 prior to the landing of the ink 4M as described above, the amount of pretreatment liquid that lands per unit area on the first surface K1 is relatively small, while the amount of pretreatment liquid that lands per unit area on the second surface K2 is relatively large. As a result, a small amount of ink lands on a small amount of pretreatment liquid on the first surface K1, while a large amount of ink lands on a large amount of pretreatment liquid on the second surface K2.

[0069] As described above, the pretreatment liquid has the function of increasing the fixation of ink on the surface of the workpiece W. For example, if the ink used has high permeability, the pretreatment liquid acts to suppress the permeation and solidify it on the surface (increasing the amount of ink that fixes). On the other hand, if the ink used has low permeability, the pretreatment liquid acts to keep the ink on the surface. In this way, the characteristics of the pretreatment liquid differ depending on the characteristics of the ink used, but in either case, the pretreatment liquid exhibits the function of increasing the fixation of ink on the surface of the workpiece W.

[0070] 10, when the amount of both the pretreatment liquid and the ink is small, the amount of ink that adheres to the surface is small, resulting in a relatively low density on the workpiece W. As a result, the relative density difference between the first surface K1 and the second surface K2, which has a large amount of both the pretreatment liquid and the ink, becomes significant, resulting in density unevenness on the workpiece W.

[0071] Similarly, after the ink 4M lands as shown in Fig. 10, when the post-processing head 6 ejects post-processing liquid while moving in the main scanning direction S1 in Fig. 10, the amount of post-processing liquid that lands per unit area on the first surface K1 is relatively small, while the amount of post-processing liquid that lands per unit area on the second surface K2 is relatively large. As a result, a small amount of post-processing liquid lands on a small amount of ink on the first surface K1, while a large amount of post-processing liquid lands on a large amount of ink on the second surface K2.

[0072] If the post-treatment liquid has the function of increasing the fixation and robustness (resistance to rubbing and scraping, abrasion resistance) of the ink image printed on the workpiece W, if there is a small amount of both ink and post-treatment liquid on the first surface K1, the amount of ink applied will be small and the abrasion resistance will be low, so after a long time has passed since printing on the workpiece W, the density will be relatively lower than other parts such as the second surface K2, and density unevenness will occur on the workpiece W. This decrease in density is also exacerbated by washing, rubbing, wind and rain, etc.

[0073] In this embodiment, in order to eliminate the density difference that occurs between areas where there is little or much of each treatment liquid and ink due to the scanning direction of each head as described above, the ink head 4, pre-treatment head 5 and post-treatment head 6 are suitably positioned on the carriage 3, and the control unit 90 suitably controls the timing of liquid ejection from each ink head.

[0074] That is, in this embodiment, as described above, if the movement of the carriage 3 when the pretreatment head 5 moves along the main scanning direction S and ejects pretreatment liquid is defined as the first scan, the movement of the carriage 3 when the ink head 4 moves along the main scanning direction S and ejects ink is defined as the second scan, and the movement of the carriage 3 when the posttreatment head 6 moves along the main scanning direction S and ejects posttreatment liquid is defined as the third scan, the movement directions of the carriage 3 differ from each other in the consecutive first and second scans. As a result, for example, a small amount of pretreatment liquid and a large amount of ink are applied to the first surface K1 in FIG. 6 , while a large amount of pretreatment liquid and a small amount of ink are applied to the second surface K2. Therefore, as described above, regions with low and high amounts of both pretreatment liquid and ink are not generated on the workpiece W due to the scanning directions of the pretreatment head 5 and the ink head 4, and density differences between the two regions can be prevented. In particular, by reducing the occurrence of areas with extremely low amounts of ink on the surface of the workpiece W, the amount of ink on the workpiece W can be made uniform, thereby reducing density unevenness. As a result, it is possible to improve the image quality of the workpiece W. When two or more rows of ink heads 4 are arranged, it is sufficient that the ink head 4 located immediately downstream of (just after) the pre-processing head 5 and the pre-processing head 5 satisfy the above relationship. The same applies when two or more rows of pre-processing heads 5 are arranged. In other words, it is sufficient that the movement direction of the carriage 3 differs between one of the first scans and one of the second scans, which are consecutive to each other.

[0075] Similarly, in this embodiment, the carriage 3 moves in different directions during the consecutive second and third scans. In this case, too, a small amount of ink and a large amount of post-treatment liquid are applied to the first surface K1 in FIG. 6 , while a large amount of ink and a small amount of post-treatment liquid are applied to the second surface K2. Therefore, as described above, regions with low and high amounts of both ink and post-treatment liquid are not generated due to the scanning directions of the ink heads 4 and post-treatment heads 6, preventing density differences between the two. In particular, the occurrence of areas with low ink amounts and low abrasion resistance is reduced, thereby reducing the occurrence of areas where the density drops significantly compared to other areas after a long period of time. As a result, density unevenness over a long period of time after printing is reduced, enabling stable images to be maintained over a long period of time and improving the quality of printed materials. Note that when two or more rows of ink heads 4 are arranged, the ink heads 4 located immediately upstream (immediately before) the post-treatment heads 6 and the post-treatment heads 6 simply need to satisfy the above relationship. The same applies when two or more rows of post-treatment heads 6 are arranged. That is, it is only necessary that the movement direction of the carriage 3 differs between one of the second scans and one of the third scans, which are consecutive to each other.

[0076] In the example of Figure 10, we explained that the amount of liquid that lands on the workpiece W changes depending on the direction of the main scan due to the inclination of the landing surface. In the case of fabrics, in addition to cases where the landing surface is simply inclined, the amount of liquid that lands on the workpiece W can also change depending on the direction of the main scan due to distortion of the shape of the convex or concave portions. In such cases, the problem can be improved as described above by reversing the scanning direction of the carriage 3 in the first movement (first scan) from the scanning direction of the carriage 3 in the second movement (second scan). Similarly, the problem can be improved as described above by reversing the scanning direction of the carriage 3 in the second movement (third scan).

[0077] Furthermore, as shown in FIG. 6 , in this embodiment, the pre-treatment head 5 has a pre-treatment nozzle region 5Z, each ink head 4 has an ink nozzle region 4Z, and the post-treatment head 6 has a post-treatment nozzle region 6Z. The pre-treatment nozzle region 5Z is an area defined by a plurality of pre-treatment nozzles that are arranged to face the workpiece W at the image forming position and each eject a pre-treatment liquid in association with the first movement of the carriage 3. Similarly, the ink nozzle region 4Z is an area defined by a plurality of ink nozzles that are arranged to face the workpiece W at the image forming position and each eject an ink in association with the second movement of the carriage 3. Furthermore, the post-treatment nozzle region 6Z is an area defined by a plurality of post-treatment nozzles that are arranged to face the workpiece W at the image forming position and each eject a post-treatment liquid in association with the third movement of the carriage 3. In Figure 6, when viewed along the main scanning direction S, the pre-processing nozzle region 5Z, the ink nozzle region 4Z and the post-processing nozzle region 6Z are arranged so as not to overlap each other, and are arranged continuously (adjacent, connected) along the transport direction F.

[0078] In this embodiment, the lengths of the pre-processing nozzle region 5Z, the ink nozzle region 4Z, and the post-processing nozzle region 6Z in the transport direction F are set to be equal to or greater than the maximum value of the transport pitch of the workpiece W (maximum feed pitch).

[0079] With this configuration, even if the work transport unit 20 transports the work W intermittently at the maximum transport pitch, no gaps are formed in the image on the work W, making it possible to form a high-quality image in a short time.

[0080] Furthermore, it is desirable that the distance in the transport direction F from the downstream end of the ink nozzle region 4Z in the transport direction F to the downstream end of the post-processing nozzle region 6Z in the transport direction F be set to be greater than or equal to the length of the ink nozzle region 4Z in the transport direction F.

[0081] This configuration makes it possible to reliably print the post-treatment liquid at a pitch at which ink can be printed, thereby preventing post-treatment liquid from running out and enabling high-quality printing to be performed in a short time. In this case, the post-treatment nozzle region 6Z may extend further upstream or downstream in the transport direction F than the range shown in FIG. 6 . Furthermore, when there are multiple rows of ink heads 4, it is sufficient that the distance in the transport direction F from the downstream end in the transport direction F of the ink nozzle region 4Z of the ink head 4 located furthest downstream in the transport direction F to the downstream end in the transport direction F of the post-treatment nozzle region 6Z is set to be equal to or greater than the length of the ink nozzle region 4Z in the transport direction F. In other words, when the ink nozzle regions 4Z of multiple rows of ink heads 4 are considered as a single ink nozzle region, it is sufficient that the distance in the transport direction F from the downstream end in the transport direction F to the downstream end in the transport direction F of the post-treatment nozzle region 6Z is set to be equal to or greater than the length of the ink nozzle region 4Z in the transport direction F.

[0082] In FIG. 6, the pre-treatment head 4 and the post-treatment head 6 are arranged at the same position in the main scanning direction S. By arranging them in this manner, the length of the carriage 3 in the main scanning direction S can be shortened. The positions of the pre-treatment head 4 and the post-treatment head 6 in the main scanning direction S relative to the first to sixth ink heads 4A to 4F can be any position. In FIG. 6, the pre-treatment head 4 and the post-treatment head 6 are arranged at the right end of the first to sixth ink heads 4A to 4F that are lined up in the main scanning direction S. By arranging them at the right end in this manner, or conversely, at the left end, when using a pre-treatment liquid or post-treatment liquid that reacts with ink, it is possible to prevent mist adhering to the carriage 3 from reacting and solidifying.

[0083] 8 and 9 are plan views showing the relationship between the pretreatment liquid landing area and the ink landing area on the workpiece W in the inkjet printer 1 according to this embodiment. In this embodiment, the ejection pattern designation unit 903 (controller 90) designates the ejection timing of the pretreatment head 5 and the ink head 4 in accordance with predetermined image information so that the area where the pretreatment liquid lands is wider than the area where the ink lands, in accordance with the image information.

[0084] As shown in Fig. 8, when an ink image is formed over a wide area on the workpiece W, a pretreatment liquid landing area 5H is set in advance over an area wider than the ink image, and the pretreatment liquid ejected from the pretreatment head 5 lands on the area. Then, ink ejected from the ink head 4 lands on the ink landing area 4H corresponding to the ink image. On the other hand, as shown in Fig. 9, even when an ink image is formed only partially on the workpiece W, it is sufficient that the pretreatment liquid landing area 5H is set wider than the ink landing area 4H. This control makes it possible to reliably apply the pretreatment liquid to the entire area where the ink is to be applied, thereby stably exerting the action of the pretreatment liquid and the ink, thereby improving print quality.

[0085] In particular, in this embodiment, the ejection pattern designation unit 903 (control unit 90) designates the ejection timing of the pretreatment head 5 and the ink head 4 so that the area 5H where the pretreatment liquid lands encompasses the area 4H where the ink lands from the periphery, as shown in Figures 8 and 9. As a result, it is possible to more reliably apply the pretreatment liquid to the entire area where the ink is to be applied.

[0086] The aspect in which the pretreatment liquid landing area 5H is set relatively wider than the ink landing area 4H is not limited to the aspect in which it is enclosed from the periphery as described above. Alternatively, the pretreatment liquid landing area 5H may be set wider than the ink landing area 4H only in the transport direction F and equally wide in the main scanning direction S, or the pretreatment liquid landing area 5H may be set wider than the ink landing area 4H only in the main scanning direction S and equally wide in the transport direction F. Furthermore, if the ink landing area 4H is ring-shaped, the pretreatment liquid landing area 5H may be a wider ring. Furthermore, the ink landing area 4H and the pretreatment liquid landing area 5H formed by the ejection of ink and pretreatment liquid from the ink head 4 and the pretreatment head 5 may be set by editing a printing pattern (print image information) in advance, or the ejection timing of each head may be set earlier or later in accordance with the printing pattern.

[0087] As described above, in a configuration in which the pretreatment liquid is printed over an entire area larger than the ink, regardless of the size of the ink image, it is possible to reduce the amount of pretreatment liquid used compared to when the entire workpiece W is immersed in the pretreatment liquid beforehand.

[0088] Furthermore, in the above-described mode in which the pretreatment liquid is selectively printed, the pretreatment liquid may be printed over a wider area than the ink in accordance with an ink printing pattern that requires greater suppression of bleeding. In this case, if the ink landing area 4H and the pretreatment liquid landing area 5H are set to the same area, printing may not be possible in necessary areas, and therefore it is desirable to expand the printing area of ​​the pretreatment liquid as described above.

[0089] Furthermore, in this embodiment, the transport speed of the workpiece W and the scanning speed of the carriage 3 are set so that the time from when the pre-treatment liquid lands on a specified pixel on the workpiece W to when the post-treatment liquid lands is within the range of 0.5 (sec) or more and 10 (sec) or less for the entire workpiece W.

[0090] This configuration ensures high print quality across the entire printing range of the workpiece W. In particular, if the time between the impact of the pre-treatment liquid and the impact of the post-treatment liquid is less than 0.5 seconds, image quality, such as color development, texture, and robustness, is likely to deteriorate. Furthermore, if the time between the impact of the pre-treatment liquid and the impact of the post-treatment liquid exceeds 10 seconds, the difference in image quality between the lower and upper limits of this time, i.e., the variation in image quality, is likely to increase.

[0091] The inkjet printer 1 according to one embodiment of the present disclosure has been described above, but the present disclosure is not limited to this and can take on modified embodiments such as those described below.

[0092] In the above embodiment, the pre-treatment head 5 has a pre-treatment nozzle region 5Z, each ink head 4 has an ink nozzle region 4Z, and the post-treatment head 6 has a post-treatment nozzle region 6Z. As shown in FIG. 6 , the pre-treatment nozzle region 5Z, the ink nozzle region 4Z, and the post-treatment nozzle region 6Z are arranged so as not to overlap with one another when viewed along the main scanning direction S. Alternatively, the regions in which the nozzles of each head are arranged may be arranged so that their ends partially overlap with one another when viewed along the main scanning direction S. In this case, it is desirable that the nozzles (actual ejection nozzles) controlled by the ejection control unit 902 to eject ink or each treatment liquid during printing are controlled so as not to overlap with one another when viewed along the main scanning direction S. In other words, in the present disclosure, the multiple nozzles (pre-treatment nozzles, ink nozzles, post-treatment nozzles) that eject liquids (pre-treatment liquid, ink, post-treatment liquid) associated with the movement (first movement, second movement, third movement) of the carriage 3 refer to the nozzles that actually eject each liquid during printing.

[0093] That is, the nozzles of each head are not limited to ejecting liquid from all pre-arranged nozzles, but may be controlled so that liquid is ejected from only some of the nozzles. Furthermore, among the pre-processing nozzle region, the ink nozzle region, and the post-processing nozzle region, it is desirable that the length of the shortest one in the transport direction F is more than half the length of the longest one. Such control makes it possible to achieve high-quality printing in a short time. Note that, in each head, it is sufficient that the multiple nozzles are arranged at least in the transport direction F, and there is no limit to the number of nozzles arranged in the main scanning direction S.

[0094] Furthermore, part or all of the control unit 90 of the inkjet printer 1 may be a personal computer that sends print image information to the inkjet printer 1. [Explanation of symbols]

[0095] 1. Inkjet printer 3 carriages 4 ink heads 4H ink landing area 4M ink 5 Pre-treatment head 5H Pretreatment liquid landing area 6 Aftertreatment Head 7 Subtank 10. Device Frame 12 Printing Area 13 Maintenance Area 14 Turning Area 20 Work transport section 90 Control Unit 901 Drive control unit 902 Discharge control section 903 Discharge pattern designation section (discharge condition designation section) 904 Storage section 91 Interface 92 Image Memory F Conveying direction K1 1st page K2 2nd side L1 Pretreatment / ink head boundary L2 ink and post-treatment head boundary M1 First motor M2 Second motor S Main scanning direction double work

Claims

1. a conveying unit that conveys the recording medium in a predetermined conveying direction; a carriage that moves back and forth along a main scanning direction that intersects with the transport direction; at least one pretreatment head mounted on the carriage and configured to eject a non-color-forming pretreatment liquid; at least one ink head mounted on the carriage and configured to eject ink; at least one post-treatment head mounted on the carriage and configured to eject a non-color-forming post-treatment liquid; Equipped with An inkjet recording device wherein, when viewed along the main scanning direction, the downstream end of the at least one pre-treatment head in the transport direction overlaps with the upstream end of the at least one ink head in the transport direction, and the downstream end of the at least one ink head in the transport direction overlaps with the upstream end of the at least one post-treatment head in the transport direction.

2. 2. The inkjet recording apparatus according to claim 1, The movement of the carriage when the pre-treatment head ejects the pre-treatment liquid while moving along the main scanning direction onto a predetermined area on the recording medium is defined as a first scan, the movement of the carriage when the ink head ejects the ink while moving along the main scanning direction onto the predetermined area is defined as a second scan, and the movement of the carriage when the post-treatment head ejects the post-treatment liquid while moving along the main scanning direction onto the predetermined area is defined as a third scan. the first scan, the second scan, and the third scan are different scans from one another, an inkjet recording apparatus, wherein the first scan, the second scan, and the third scan are each performed at least once in this order;

3. 3. The inkjet recording apparatus according to claim 2, An inkjet recording apparatus, wherein the carriage moves in different directions in the first scan and the second scan, which are successive to each other.

4. 4. The inkjet recording apparatus according to claim 2, wherein The inkjet recording apparatus, wherein the second scan and the third scan, which are successive to each other, have different moving directions of the carriage.

5. 5. The inkjet recording apparatus according to claim 1, the at least one pretreatment head has a pretreatment nozzle region defined by a plurality of pretreatment nozzles that each eject a pretreatment liquid in association with movement of the carriage; the at least one ink head has an ink nozzle area defined by a plurality of ink nozzles each of which ejects ink as the carriage moves; the at least one post-processing head has a post-processing nozzle area defined by a plurality of post-processing nozzles that each eject a post-processing liquid in association with movement of the carriage; an inkjet recording apparatus, wherein the pre-processing nozzle region, the ink nozzle region, and the post-processing nozzle region are arranged so as not to overlap one another when viewed along the main scanning direction;

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

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

8. 8. The inkjet recording apparatus according to claim 1, an inkjet recording apparatus further comprising a plurality of sub-tanks arranged side by side in the main scanning direction on the carriage, the sub-tanks supplying ink or treatment liquid to the at least one pre-treatment head, the at least one ink head, and the at least one post-treatment head;

9. 6. The inkjet recording apparatus according to claim 5, the conveying unit intermittently conveys the recording medium at a predetermined conveying pitch; an inkjet recording apparatus, wherein the lengths of the pre-processing nozzle region, the ink nozzle region, and the post-processing nozzle region in the transport direction are set to be equal to or greater than the maximum value of the transport pitch;

10. 10. The inkjet recording apparatus according to claim 5 or 9, an inkjet recording apparatus, wherein a distance in the transport direction from a downstream end of the ink nozzle region in the transport direction to a downstream end of the post-processing nozzle region in the transport direction is set to be equal to or greater than a length of the ink nozzle region in the transport direction.

11. 11. The inkjet recording apparatus according to claim 1, an inkjet recording apparatus, further comprising: a control unit that specifies ejection timings of the pretreatment head and the ink head in accordance with predetermined image information so that an area where the pretreatment liquid corresponding to the image information lands is wider than an area where the ink lands and encompasses the area where the ink lands.

12. 12. The inkjet recording apparatus according to claim 1, an inkjet recording apparatus, wherein a conveying speed of the recording medium and a scanning speed of the carriage are set so that a time from when the pre-treatment liquid lands on a predetermined pixel on the recording medium until when the post-treatment liquid lands on the entire recording medium is within a range of 0.5 (sec) to 10 (sec).

13. 13. The inkjet recording apparatus according to claim 1, the at least one pretreatment head has a pretreatment nozzle region defined by a plurality of pretreatment nozzles that each eject a pretreatment liquid in association with movement of the carriage; the at least one ink head has an ink nozzle area defined by a plurality of ink nozzles each of which ejects ink as the carriage moves; the at least one post-processing head has a post-processing nozzle area defined by a plurality of post-processing nozzles that each eject a post-processing liquid in association with movement of the carriage; an inkjet recording apparatus, wherein the length of the pre-processing nozzle region, the ink nozzle region, and the post-processing nozzle region, whichever is shortest in the transport direction, is longer than half the length of the longest one;

14. a conveying unit that conveys the recording medium in a predetermined conveying direction; a carriage that moves back and forth along a main scanning direction that intersects with the transport direction; at least one pretreatment head mounted on the carriage and configured to eject a non-color-forming pretreatment liquid; at least one ink head mounted on the carriage and configured to eject ink; at least one post-treatment head mounted on the carriage and configured to eject a non-color-forming post-treatment liquid; An inkjet recording method for an inkjet recording apparatus comprising: an inkjet recording method comprising arranging the at least one pre-treatment head so that, when viewed along the main scanning direction, a downstream end of the at least one pre-treatment head in the transport direction overlaps with an upstream end of the at least one ink head in the transport direction, and a downstream end of the at least one ink head in the transport direction overlaps with an upstream end of the at least one post-treatment head in the transport direction.

Images