Ink-jet recording device and ink-jet 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 including an ink head mounted on a carriage that moves in a main scanning direction, and an inkjet recording method. [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 the recording process, 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. During the movement of the carriage, 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 color inks onto the recording medium, and a posttreatment liquid is applied to the recording medium after ejecting color inks onto the recording medium. The pretreatment liquid is, for example, a treatment liquid for improving the fixability of ink to the recording medium and the coagulation property of ink pigments. The posttreatment liquid is, for example, a treatment liquid for improving the robustness of a printed image. The carriage of the inkjet recording device is provided 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] JP 2017-094673 A Summary of the Invention

[0006] An inkjet recording device 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-coloring 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-coloring 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 description 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. [Diagram 2] FIG. 2 is a schematic cross-sectional view taken along line II-II in FIG. [Diagram 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 a printing state during the forward and return passes of the carriage. [Figure 5B] FIG. 5B is a schematic diagram showing a printing state during the forward and return passes of the carriage. [Figure 6] FIG. 6 is a plan view that shows a schematic arrangement of the ink heads and the 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 PREFERRED EMBODIMENTS

[0008] In the following, an inkjet recording apparatus according to each embodiment of the present disclosure will be described with reference to the drawings. In these embodiments, an inkjet printer equipped with an ink head that ejects ink for forming an image on a wide and long recording medium is exemplified as a specific example of an inkjet recording apparatus. Inkjet printers are suitable for digital textile printing that uses an inkjet method to print images such as characters and patterns on a recording medium made of fabric such as woven fabric or knitted fabric. Of course, the inkjet recording apparatus according to the present disclosure can also be used for printing 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) by an inkjet method, and includes a device frame 10, and a work transport section 20 (transport section) and a carriage 3 that are incorporated into this device frame 10. Note that in this embodiment, the left-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 (transport direction F of 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 subtank 7, and moves back and forth in a main scanning direction S (left-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-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 the nozzles are also capped. The left frame 113 forms a turn-around area 14 for the carriage 3. The turn-around 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 from right to left in the printing process.

[0013] A carriage guide 15 for reciprocating the carriage 3 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, and is driven by a carriage drive unit 3S described below so as to move in a circular motion in the left or right direction.

[0014] A pair of upper and lower guide rails 17 (holding members) that hold the carriage 3 in a state that allows it to move back and forth in the main scanning direction S are provided on the carriage guide 15 so as to extend parallel to the left and right direction. The carriage 3 engages with the guide rails 17. The carriage 3 is also fixed to a timing belt 16. As the timing belt 16 moves in a circumferential direction to the 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 mainly 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 disposed 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 disposed 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 executes 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 work W. On this transport path, 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 are arranged in this order from the upstream side. The first tension roller 23 applies a predetermined tension to the work W on the upstream side of the transport roller 25. The work guide 24 changes the transport direction of the work W from the upward direction to the forward direction, and allows the work 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 about 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 so as to face the transport roller 25 from above, and forms a transport nip portion together with the transport roller 25.

[0018] The turn-back roller 27 changes the transport direction of the work W that has passed through the printing area 12 from the forward direction to the downward direction, and guides the work W after the printing process to the take-up roller 22. The second tension roller 28 applies a predetermined tension to the work W downstream of the transport roller 25. A platen 29 is disposed below the transport path of the work W in the printing area 12.

[0019] The carriage 3, supported at one end by a guide rail 17, 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 includes a carriage frame 30, and an ink head 4, a pre-processing head 5, a post-processing head 6, and a subtank 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 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. Also, 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 present only on one side, either the upstream side or the downstream side, from the center of the carriage 3 in the transport direction F, and no other engagement portion is present on the opposite side to 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 the 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 the 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 work W and the main scanning direction S which is the moving direction of the carriage 3. Fig. 3 shows an example in which the carriage 3 is equipped with a plurality of ink heads 4 which eject ink for forming an image onto the work W, a pre-treatment head 5 and a post-treatment head 6 which eject a non-color-forming treatment liquid, and a plurality of sub-tanks 7 which supply the ink and the treatment liquid to these heads 4 to 6.

[0023] Each of the ink heads 4 includes a number of nozzles (ink ejection holes) that eject ink droplets by an ejection method such as a piezoelectric method using a piezoelectric element or a thermal method using a heating element, and an ink passage that guides the ink to the nozzles. As the ink, for example, a water-based pigment ink containing a water-based solvent, a pigment, and a binder resin can be used. The ink may contain a dye instead of a pigment. Therefore, hereinafter, a concept including a pigment and a dye may be expressed as a coloring matter. The ink heads 4 in this embodiment include first to sixth ink heads 4A to 4F that eject 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 the post-treatment head 6 are disposed at positions different 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 provided 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 for performing 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-coloring treatment liquid that does not develop color even when attached to the workpiece W, and is a treatment liquid that exhibits functions such as increasing the fixation of ink to the workpiece W and the coagulation of ink pigments (dyes). As such a pretreatment liquid, 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, can be used.

[0027] The post-treatment head 6 ejects a post-treatment liquid for performing a predetermined post-treatment on the workpiece W to which the ink has been attached. The post-treatment liquid is ejected from the post-treatment head 6 to a position on the workpiece W after the ink has been ejected from the ink head 4. The post-treatment liquid is a non-coloring treatment liquid that does not develop color even when it is attached to the workpiece W, and is a treatment liquid that exhibits a function of increasing the fixability and robustness (resistance to rubbing and scraping) of the ink image printed on the workpiece W by the ink head 4. As such a post-treatment liquid, a silicone-based treatment liquid or the like can be used. 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, the non-coloring treatment liquid refers to a treatment liquid that is not recognized as colored by the naked eye when printed alone on a recording medium. The color here includes colors with a saturation of 0, such as black, white, and gray. The non-coloring treatment liquid is basically a transparent liquid, but when, for example, 1 liter of treatment liquid is viewed in liquid form, it is not completely transparent and may appear slightly white. Such a color is very light, so when printed alone on a recording medium, it is not recognized as colored by the naked eye. Note that, depending on the type of treatment liquid, when printed alone on a recording medium, a change such as glossiness may occur on the recording medium, but such a state is not colored.

[0029] In this embodiment, the pre-treatment liquid and the post-treatment liquid may be ejected onto substantially 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, the ink, and the posttreatment liquid are ejected in this order onto the workpiece W in the portion where the color is printed according to the image. In this case, the ink may be of one color or of multiple colors. Basically, the pretreatment liquid and the posttreatment liquid are not ejected onto the portion where the color is not printed, that is, the portion where the ink is not ejected. Note that, in order to adjust the image quality of the printed image and the texture of the workpiece W, the selection of the 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, the pre-treatment head 5, and the post-treatment head 6 are assembled to the head support frame 31 so as to be fitted into each of the openings 31H. Nozzles arranged on the lower end surface of each of the heads 4, 5, and 6 are exposed from each of the openings 31H.

[0032] The subtank 7 is supported by the carriage 3 above the heads 4, 5, and 6 via a holding frame (not shown). A subtank 7 is provided corresponding to each of the heads 4, 5, and 6. Ink or treatment liquid is supplied to each subtank 7 from a cartridge (not shown) or a main tank that contains ink and treatment liquid. Each subtank 7 supplies the ink or treatment liquid to each of the heads 4, 5, and 6. Each subtank 7 and the heads 4, 5, and 6 are connected by pipelines (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, the pre-treatment head 5, and the post-treatment head 6, are mounted on a single carriage 3. With this inkjet printer 1, for example, in the printing process of performing inkjet printing on fabric in digital textile printing, the process of ejecting the pre-treatment liquid and the process of ejecting the post-treatment liquid can be executed integrally. This makes it possible to simplify the textile printing process and make the textile printing device more compact.

[0034] [Print method] Next, a printing method executed 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. Fig. 4 is a schematic diagram showing the serial printing method. In Fig. 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 has a wide size, it is not possible to print while continuously feeding the workpiece W. The serial printing method is a printing method in which the carriage 3 carrying the 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. 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 arrangement range of the ink ejection nozzles of the ink heads 4. Note that in FIG. 4 and FIGS. 5A and 5B described below, the width of each head in the transport direction F and the printing width Pw are drawn 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 a state in which the carriage 3 moves in the forward direction SA in the main scanning direction S and printing of a strip-shaped image G1 with a printing width Pw is completed. During this main scanning in the forward direction SA, the feeding of the workpiece W is stopped. After printing of 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 turn-back area 14 on the left end side. After sending out the workpiece W, the carriage 3 turns back in the return direction SB in accordance with the reverse movement of the timing belt 16. The workpiece W is in a stopped 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 on the upstream side of the strip-shaped image G1. Thereafter, the same operation is repeated.

[0037] 5A and 5B are schematic diagrams showing the printing status of the carriage 3 on the forward and return passes. Here, the ink head 4, pre-treatment head 5, and post-treatment head 6 mounted on the carriage 3 are shown simply. 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, and 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 disposed upstream of the ink head 4 in the transport direction F, and the post-treatment head 6 is disposed downstream of the ink head 4. As in the case described in FIG. 4, the work W is sent out in the transport direction F between the printing of the forward pass and the printing of the return pass. The moving distance in the transport direction F at this time is the interval pitch (head pitch) between the heads adjacent to each other in the transport direction F. This moving distance is also 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 while moving in the outward direction SA in the main scanning direction S (outward main scanning). An 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. In this outward main scanning, a pretreatment layer Lpre is formed on the area A4 by the pretreatment liquid ejected from the pretreatment head 5.

[0039] The region A3 is a region one head pitch downstream of the region A4, and is a region facing the ink head 4. A pre-treatment layer Lpre has already been formed on the region A3 over the entire length in the main scanning direction by the previous backward main scanning. In the current forward main scanning, the first, second, third and fourth ink layers LCA, LCB, LCC and LCD are formed on the pre-treatment layer Lpre of the region A3 by the first to fourth color inks ejected in order from the first to fourth ink heads 4A to 4D. Note that in FIG. 5A, the fourth to first ink layers LCD to LCA are illustrated as being stacked in order for ease of understanding, but 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 an area 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 by the previous outward main scan and first to fourth ink layers LCA to LCD by the previous return main scan have already been formed over the entire length in the main scanning direction on region A2. In the current outward main scan, a post-processing layer Lpos is formed by the post-processing liquid ejected from the post-processing head 6 on the first to fourth ink layers LCA to LCD in region A2.

[0041] Region A1 is an area one head pitch downstream of region A2, where the carriage 3 has passed and printing process 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] Fig. 5B shows a 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 an area one head pitch upstream of area A4, and is the area that faces the pre-treatment head 5 in this return main scan. A pre-treatment layer Lpre is formed on area A5 by the pre-treatment liquid ejected from the pre-treatment head 5.

[0043] In the regions A4 and A3, the first to fourth ink layers LCA to LCD and the post-treatment layer Lpos are respectively formed on the existing layers. Specifically, in the region A4, the first to fourth ink layers LCA to LCD are formed on the pre-treatment layer Lpre. In the region A3, the post-treatment layer Lpos is formed on the first to fourth ink layers LCA to LCD. The region A2 is the region where the printing process is completed following the region A1.

[0044] The reason why printing can be performed in both the forward main scanning and the backward main scanning as described above is because the pre-treatment head 5 and the post-treatment head 6 are arranged by shifting them in the transport direction F with respect to the ink head 4. If the pre-treatment head 5, the ink head 4, and the post-treatment head 6 were arranged in a line in this order in the main scanning direction S on the carriage 3, the printing process that can deposit the pre-treatment liquid and the post-treatment liquid in a desired landing order can only be achieved in one of the forward or backward main scanning. To enable bidirectional printing, the pair of the pre-treatment head 5 and the post-treatment head 6 must be arranged on both sides of the array of the ink heads 4. In this case, the width of the carriage 3 in the main scanning direction S becomes large. Since such an arrangement is unnecessary in this embodiment, the width of the carriage 3 in the main scanning direction S can be reduced.

[0045] Incidentally, 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, when 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 the head arrangement on the carriage 3 according to the present embodiment, and also shows the arrangement of the ink head 4, pre-treatment head 5 and post-treatment head 6 (multiple treatment heads) on the carriage 3 shown in FIG. 3. As described above, the carriage 3 is equipped with the first to sixth ink heads 4A to 4F, the pre-treatment head 5 and the post-treatment head 6, which eject ink of six different colors. Each color ink head 4A to 4F, the pre-treatment head 5 and the post-treatment head 6 are provided in one piece. The group of the first to sixth ink heads 4A to 4F constituting the ink head 4 is arranged in the main scanning direction S in the central region of the carriage 3 in the transport direction F. In addition, when viewed along the main scanning direction S, the downstream end of the pre-treatment head 5 in the transport direction F is arranged to overlap (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 disposed so as to overlap with the upstream end of the post-treatment head 6 in the transport direction F.

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

[0048] In Fig. 6, the nozzle region arranged on the underside of the head is shown by a dashed line inside the external shape of each head. The nozzle region is an area defined by the nozzles arranged on the underside of each head that eject liquid when 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 end and downstream end of the nozzle regions of the first ink head 4A to the sixth ink head 4F in the transport direction F are arranged at the same position as each other in the transport direction F. Furthermore, the upstream end of the nozzle regions of the first ink head 4A to the sixth ink head 4F in the transport direction F is arranged 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 arranged 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] 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 drive unit 3S, an I / F 91, and an image memory 92. The control unit 90 includes a CPU (Central Processing Unit), a ROM (Read Only Memory) that stores a control program, a RAM (Random Access Memory) that is used as a work area for the CPU, and the like. In addition to the first motor M1 and second motor M2, the ink head 4, the pre-processing head 5, and the post-processing head 6, the carriage drive unit 3S, the I / F 91, the image memory 92, and the like are electrically connected to the control unit 90. The carriage drive unit 3S includes a motor (not shown) that rotates a timing belt 16 to reciprocate the carriage 3 along the main scanning direction S, and the like.

[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 side 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. In addition, the drive control unit 901 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 ejection amount (ejection pattern) of ink from the ink head 4 of each color, and inputs a signal 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, and the like 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-mentioned embodiment, and may be different from the above-mentioned embodiment depending on the structure of the device and program, etc. In other words, it can be said that the functions of the drive control unit 901, the discharge control unit 902, the discharge pattern designation unit 903, and the storage unit 904 are executed by the control unit 90.

[0060] <Ejection of each treatment liquid and ink> 6, in the head arrangement in this embodiment, one pre-treatment head 5 is disposed upstream of the ink head 4 in the transport direction F, and one post-treatment head 6 is disposed downstream. That is, it is possible to provide an all-in-one inkjet printer 1 in which three types of heads, heads for ejecting pre-treatment liquid, ink, and post-treatment liquid, are mounted on one carriage 3. In addition, because the pre-treatment head 5, ink head 4, and post-treatment head 6 are disposed 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 is equipped with a work transport section 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 mounted on the carriage 3 and ejecting a non-colorable pre-treatment liquid, an ink head 4 mounted on the carriage 3 and ejecting ink, and a post-treatment head 6 mounted on the carriage 3 and ejecting a non-colorable post-treatment liquid. When the ejection control unit 902 controls the ejection of each head according to the movement of the carriage 3 in the main scanning direction S, the pre-treatment head 5 ejects the 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. 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 including the pre-treatment liquid, ink, and post-treatment liquid on the recording area. For this reason, in this embodiment, the pre-treatment head 5, the ink head 4, and the post-treatment head 6 are arranged so as to be shifted from each other in the transport direction F (FIG. 6). For this reason, the pre-treatment liquid, the ink, and the post-treatment liquid can be applied reliably and stably to the workpiece W in this order. As a result, it is possible to reliably achieve high-quality printing on the workpiece W. Note that, as an example, the first movement of the carriage 3 is one direction in the main scanning direction S (from right to left in FIG. 6), the second movement is the other direction in the main scanning direction S (from left to right in FIG. 6), and the third movement is 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 ejects the pre-treatment liquid while moving along the main scanning direction S to a predetermined area on the workpiece W is defined as a first scan, the movement of the carriage 3 when the ink head 4 ejects the ink while moving along the main scanning direction S to the predetermined area is defined as a second scan, and the movement of the carriage 3 when the post-treatment head 6 ejects the post-treatment liquid while moving along the main scanning direction S to the predetermined area is defined as a third scan. The first scan, the second scan, and the third scan are different from each other, 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, the ink, and the post-treatment liquid can be applied to the workpiece W more reliably in this order. 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 the embodiment in which one row of ink heads 4 is arranged along the main scanning direction S, but may 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 as well, it is sufficient that the pre-treatment head 5, ink head 4, and post-treatment head 6 are arranged in this order, shifted 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 by a cantilever in this manner, the pre-processing head 5 is disposed on the base end side 311 (the side closer to the engaging 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 engaging portion). Unlike the base end side 311 close to the back frame 32 fixed to the timing belt 16, it is expected that the positional accuracy will 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 high degree of accuracy in ejection. Since the post-processing liquid is used to coat the ink image printed on the workpiece W, even if the landing position shift occurs, the relative impact on the image quality can be made smaller than if the landing position shift occurs to the same extent for the pre-processing liquid. Therefore, even when the carriage 3 supported by a cantilever is used, it is possible to make it difficult for the quality of the image to be degraded.

[0066] <Issues with carriage scanning> FIG. 10 is a schematic diagram showing how the ink 4M lands on the surface of the workpiece W as the carriage 3 moves. When the workpiece W is made of fabric such as woven fabric or knitted fabric, or when the workpiece W is paper made of paper fibers, various irregularities exist on the surface. In the case of fabric, there are undulations on the surface caused by the weaving or knitting process, and irregularities exist between adjacent threads depending on the thickness and twisting of the thread. Generally, these irregular shapes are larger than the ink dot diameter of about several tens of microns, and even if they are not, they are of a size that cannot be ignored compared to the ink dot diameter. In addition, in the case of paper, there are minute irregularities due to the random distribution of paper fibers on the surface, and depending on the type of paper, the irregularities may be of a size that cannot be ignored compared to the ink dot diameter. In other words, recording media such as fabrics and certain types of paper may have irregular shapes on their surfaces with a period that cannot be ignored compared to the diameter of the ink dots ejected.

[0067] In FIG. 10, when the ink head 4 ejects the ink 4M while moving in the main scanning direction S1 from right to left on the paper surface by the movement of a carriage (not shown), the moving speed of the ink head 4 and the ejection speed of the ink 4M are combined, so that each ink 4M lands on the workpiece W while tilting along the direction shown by the arrow in FIG. 10. In this case, if the workpiece W has an uneven shape in which the first surface K1 and the second surface K2, which are tilted, are alternately present, as shown in FIG. 10, the amount of ink 4M that lands (amount of application) per unit area is relatively small on the first surface K1, which is nearly parallel to the ejection direction of the ink 4M, while the amount of ink 4M that lands per unit area is relatively large on the second surface K2, which is nearly perpendicular to the ejection direction of the ink 4M. This phenomenon occurs because the area on which the same amount of ink 4M lands on the first surface K1 is larger than that on the second surface K2.

[0068] 10, the amount of pretreatment liquid per unit area that lands on the first surface K1 is relatively small, whereas the amount of pretreatment liquid per unit area that lands 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, whereas 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 the ink on the surface of the workpiece W. For example, when the ink used has high permeability, the pretreatment liquid acts to suppress the permeation and solidify the ink on the surface (increasing the amount of ink that fixes). On the other hand, when the ink used has low permeability, the pretreatment liquid acts to retain 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 any case, the pretreatment liquid exerts the function of increasing the fixation of the ink on the surface of the workpiece W.

[0070] 10, the amount of ink fixed on 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, 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 becomes relatively small, while the amount of post-processing liquid that lands per unit area on the second surface K2 becomes 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] In the case where the post-treatment liquid has the function of increasing the fixability 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 is small and the abrasion resistance is low, so that after a long time has passed since printing on the workpiece W, the density becomes relatively lower than other parts such as the second surface K2, causing uneven density on the workpiece W. The decrease in density as described above is also exacerbated by washing, rubbing, wind and rain, etc.

[0073] In this embodiment, in order to eliminate the concentration difference that occurs between areas where there is little treatment liquid and ink and areas where there is much of both 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 ejects the pretreatment liquid while moving along the main scanning direction S is defined as the first scan, the movement of the carriage 3 when the ink head 4 ejects the ink while moving along the main scanning direction S is defined as the second scan, and the movement of the carriage 3 when the posttreatment head 6 ejects the posttreatment liquid while moving along the main scanning direction S is defined as the third scan, the movement directions of the carriage 3 are different from each other in the first scan and the second scan, which are successive to each other. 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 little pretreatment liquid and ink and regions with much pretreatment liquid and ink are not generated on the workpiece W due to the scanning direction of the pretreatment head 5 and the ink head 4, and it is possible to prevent the generation of a density difference between the two. In particular, by reducing the generation of portions where the amount of ink present on the surface of the workpiece W is extremely small, the amount of ink on the workpiece W can be made uniform and density unevenness can be reduced. As a result, it is possible to improve the image quality of the workpiece W. When the ink heads 4 are arranged in two or more rows, it is only necessary that the ink heads 4 located immediately downstream (immediately after) the pre-treatment heads 5 and the pre-treatment heads 5 satisfy the above relationship. The same is true when the pre-treatment heads 5 are arranged in two or more rows. In other words, it is only necessary that the movement directions of the carriage 3 differ between one of the first scans and one of the second scans, which are consecutive to each other.

[0075] Similarly, in this embodiment, the moving directions of the carriage 3 are different between the second scan and the third scan, which are successive to each other. 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, there is no occurrence of an area with a small amount of both ink and post-treatment liquid and an area with a large amount of both due to the scanning direction of the ink head 4 and the post-treatment head 6, and it is possible to prevent the occurrence of a density difference between the two. In particular, the occurrence of a portion with a small amount of ink and low abrasion resistance is reduced, so that it is possible to reduce the occurrence of a portion in which the density after a long time has passed is extremely lower than other portions. As a result, the density unevenness when a long time has passed after printing is reduced, and it is possible to maintain a stable image for a long time and improve the quality of the printed matter. In addition, when the ink heads 4 are arranged in two or more rows, it is sufficient that the ink heads 4 and the post-treatment heads 6 located immediately upstream (immediately before) of the post-treatment heads 6 satisfy the above relationship. The same applies when the post-treatment heads 6 are arranged in two or more rows. In other words, it is only necessary that the movement direction of the carriage 3 be different between one of the second scans and one of the third scans, which are consecutive to each other.

[0076] In the example of FIG. 10, it has been explained that the landing amount of the liquid changes depending on the main scanning direction due to the inclination of the landing surface of the workpiece W. In the case of fabrics, in addition to the case where the landing surface is simply inclined, the amount of the liquid landing may change depending on the main scanning direction due to the distortion of the shape of the convex or concave portion. In such a case, too, it is possible to improve as described above by reversing the scanning direction of the carriage 3 in the first movement (first scan) and the scanning direction of the carriage 3 in the second movement (second scan). Similarly, it is possible to improve as described above by reversing the scanning direction of the carriage 3 in the second movement (third scan).

[0077] Further, 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. Further, 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 FIG. 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 (connected, adjacent) along the transport direction F.

[0078] In this embodiment, the length in the transport direction F of each of the pre-processing nozzle region 5Z, the ink nozzle region 4Z and the post-processing nozzle region 6Z is set to be equal to or greater than the maximum 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 period of 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] According to this configuration, the post-treatment liquid can be reliably printed at a pitch at which the ink can be printed, so that the post-treatment liquid does not run out and high-quality printing can 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 of FIG. 6. In addition, when there are multiple ink heads 4, the distance in the transport direction F from the downstream end of the ink nozzle region 4Z in the transport direction F of the ink head 4 that is the most downstream in the transport direction F to the downstream end of the post-treatment nozzle region 6Z in the transport direction F may be set to be equal to or greater than the length of the ink nozzle region 4Z in the transport direction F. In other words, the distance in the transport direction F from the downstream end in the transport direction F to the downstream end of the post-treatment nozzle region 6Z in the transport direction F when the ink nozzle regions 4Z of the multiple ink heads 4 are regarded as one ink nozzle region may be 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 disposed at the same position in the main scanning direction S. By disposing them in this way, 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 may be any position relative to the first to sixth ink heads 4A to 4F. In FIG. 6, the pre-treatment head 4 and the post-treatment head 6 are disposed at the right end of the first to sixth ink heads 4A to 4F aligned in the main scanning direction S. By disposing them at the right end in this way, 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 the 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 (control unit 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 partially formed on the workpiece W, it is sufficient that the pretreatment liquid landing area 5H is set wider than the ink landing area 4H. Such control makes it possible to reliably apply the pretreatment liquid to the entire area where the ink is applied, and therefore the print quality can be improved by stably exerting the action of the pretreatment liquid and the ink.

[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 the pretreatment liquid landing area 5H is surrounded by the surroundings as described above, and 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, when the ink landing area 4H is ring-shaped, the pretreatment liquid landing area 5H may be a wider ring-shaped area. The ink landing area 4H and the pretreatment liquid landing area 5H formed by ejecting the ink and the pretreatment liquid from the ink head 4 and the pretreatment head 5 may be set by editing a printing pattern (printing image information) in advance, or the ejection timing of each head may be set earlier or later in accordance with the printing pattern.

[0087] In addition, 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 also possible to reduce the amount of pretreatment liquid used compared to a case in which the entire workpiece W is immersed in the pretreatment liquid in advance.

[0088] In the above-mentioned embodiment 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 in which suppression of bleeding is more important. 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 the required areas, so 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 the impact of the pre-treatment liquid on a specified pixel on the workpiece W to the impact of the post-treatment liquid is within the range of 0.5 (sec) or more and 10 (sec) or less over the entire workpiece W.

[0090] According to this configuration, high print quality can be ensured over the entire printing range of the workpiece W. In particular, when the time from the impact of the pre-treatment liquid to the impact of the post-treatment liquid is less than 0.5 (sec), image quality such as color development, texture, and fastness is likely to decrease. Also, when the time from the impact of the pre-treatment liquid to the impact of the post-treatment liquid exceeds 10 (sec), the difference in image quality between the lower limit and the upper limit of the time, i.e., the variation in image quality, is likely to increase.

[0091] The ink jet 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, in a configuration in which 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 each other when viewed along the main scanning direction S. On the other hand, the regions in which the nozzles of each head are arranged may be arranged so that their ends partially overlap each other when viewed along the main scanning direction S. In this case, it is preferable 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 each other when viewed along the main scanning direction S. That is, 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) in association 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 those that eject liquid from all pre-arranged nozzles, but may be controlled so that liquid is ejected from some of the nozzles. Also, among the pre-processing nozzle region, the ink nozzle region, and the post-processing nozzle region, it is desirable that the length of the one having the shortest length in the transport direction F is longer than half the length of the one having the longest length. With this type of control, high-quality printing can be achieved in a short time. Note that in each head, it is sufficient that the multiple nozzles are arranged at least side by side in the transport direction F, and the number of nozzles arranged in the main scanning direction S is not limited.

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

[0095] 1. Inkjet printer 3 Carriage 4 Ink head 4H ink landing area 4M Ink 5 Pre-treatment head 5H Pretreatment liquid landing area 6 Aftertreatment Head 7 Subtank 10 Equipment Frame 12 Printing Area 13 Maintenance Area 14 Turnaround Area 20 Work transport section 90 Control section 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 page L1 Pretreatment / ink head boundary L2 Ink / Post-treatment Head Boundary M1 First motor M2 2nd motor S Main scanning direction W work

Claims

1. A conveying unit that conveys the recording medium in a predetermined conveying direction; a carriage that reciprocates 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 developing 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 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 first scan and the second scan, which are successive to each other, have different moving directions of the carriage.

4. 4. The inkjet recording apparatus according to claim 2, an 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 each of which ejects 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 in association with movement of the carriage; the at least one post-processing head has a post-processing nozzle area defined by a plurality of post-processing nozzles each of which ejects a post-processing liquid in association with movement of the carriage; an ink jet 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 with each other when viewed along the main scanning direction.

6. In the inkjet recording apparatus according to any one of claims 1 to 5, The recording medium is made of a material, The pretreatment liquid is dropped onto the predetermined position of the fabric before the ink is dropped onto the predetermined position of the fabric.

7. In the inkjet recording apparatus according to any one of claims 1 to 6, The recording medium is made of a material, The post-treatment liquid is ejected onto the predetermined position on the fabric after the ink is ejected onto the predetermined position.

8. In the inkjet recording apparatus according to any one of claims 1 to 7, 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. An inkjet recording apparatus according to any one of claims 1 to 8, the conveying unit conveys the recording medium intermittently at a predetermined conveying pitch, an inkjet recording apparatus, wherein the length in the transport direction of each of the pre-processing nozzle region, the ink nozzle region and the post-processing nozzle region is set to be equal to or greater than the maximum value of the transport pitch; 10. The inkjet recording apparatus according to claim 1, an inkjet recording device, 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 greater than or equal to a length of the ink nozzle region in the transport direction.

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

12. The inkjet recording apparatus according to claim 1, an inkjet recording device, 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 specified pixel on the recording medium to when the post-treatment liquid lands on the entire recording medium is within a range of 0.5 (sec) to 10 (sec).

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 each of which ejects 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 in association with movement of the carriage; the at least one post-processing head has a post-processing nozzle area defined by a plurality of post-processing nozzles each of which ejects 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 in the transport direction that is the shortest is longer than half the length of the longest one of the pre-processing nozzle region, the ink nozzle region and the post-processing nozzle region.

14. A conveying unit that conveys the recording medium in a predetermined conveying direction; a carriage that reciprocates 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 developing 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