Inkjet recording apparatus and inkjet recording method

Abstract

An inkjet recording device includes a transport unit, a carriage, a plurality of ink head arrays, a pre-processing head, and a post-processing head. The pre-processing head ejects a non-colored pre-processing liquid. The post-processing head ejects a non-colored post-processing liquid. Assuming that the head closest to one end in the main scanning direction is the one-end head, the head closest to the other end is the other-end head, the distance from the one-end head to the other-end head in the main scanning direction is LC, the distance from the one-end head to the pre-processing head in the main scanning direction is B1, and the distance from the one-end head to the post-processing head in the main scanning direction is B2, the relationship 1 / 2 ≤ (B1 + B2) / LC ≤ 3 / 2 is satisfied.

Description

Technical Field

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

[0002] Inkjet recording devices such as inkjet printers include an ink head that ejects ink for image formation toward a recording medium. For example, when the recording medium is a fiber sheet such as a woven or knitted fabric, or a plastic sheet, it may be necessary to apply a pre-treatment liquid and a post-treatment liquid to the recording medium before and after the ink is ejected onto the recording medium (e.g., Patent Document 1). The pre-treatment liquid is, for example, a treatment liquid used to improve the fixability of the ink to the recording medium and the cohesion of the ink pigment. The post-treatment liquid is, for example, a treatment liquid used to improve the firmness of the printed image. In this case, the inkjet recording device includes a treatment head for ejecting the pre-treatment liquid and the post-treatment liquid in addition to the ink head.

[0003] When recording media is wide, the ink head and processing heads are mounted on a carriage that reciprocates in the main scanning direction. During recording, the recording medium is intermittently transported in a predetermined transport direction (sub-scanning direction). When the recording medium is stopped, the carriage reciprocates in the main scanning direction. As the carriage moves, ink and processing fluid are ejected from the ink head and processing heads, respectively.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Publication No. 2019-147307 Summary of the Invention

[0007] An inkjet recording device according to one aspect of the present invention includes a conveying unit, a carriage, a plurality of ink head arrays, a pre-processing head, and a post-processing head. The conveying unit conveys the recording medium along a predetermined conveying direction. The carriage reciprocates along a main scanning direction intersecting the conveying direction. The plurality of ink head arrays are mounted on the carriage in a manner arranged along the conveying direction, and the plurality of ink head arrays are an even number of ink head arrays. The pre-processing head is arranged on the upstream side relative to the plurality of ink head arrays in the conveying direction, and ejects a non-colored pre-processing liquid. The post-processing head is arranged on the downstream side relative to the plurality of ink head arrays in the conveying direction, and ejects a non-colored post-processing liquid. Each of the plurality of ink head arrays includes a plurality of ink heads arranged in a manner arranged along the main scanning direction, each of which ejects ink for image formation. When the head closest to one end side among the multiple ink heads, the pre-processing heads and the post-processing heads in the main scanning direction is called the one end side head, the head closest to the other end side is called the other end side head, the distance from the one end side head to the other end side head in the main scanning direction is LC, the distance from the one end side head to the pre-processing head in the main scanning direction is B1, and the distance from the one end side head to the post-processing head in the main scanning direction is B2, the pre-processing head and the post-processing head are arranged in a manner that satisfies the relationship of Formula 1.

[0008] 1 / 2≤(B1+B2) / LC≤3 / 2 (Formula 1)

[0009] In addition, another aspect of the present invention relates to an inkjet recording device that includes a conveying unit, a carriage, one or more ink head columns, a pre-processing head, and a post-processing head. The conveying unit conveys the recording medium along a specified conveying direction. The carriage moves back and forth along a main scanning direction that intersects the conveying direction. The one ink head column is mounted on the carriage at a specified position in the conveying direction. The multiple ink head columns are mounted on the carriage in a manner arranged along the conveying direction, and the multiple ink head columns are an odd number of ink head columns. The pre-processing head is arranged on the upstream side of the one or more ink head columns in the conveying direction and ejects a non-colored pre-processing liquid. The post-processing head is arranged on the downstream side of the one or more ink head columns in the conveying direction and ejects a non-colored post-processing liquid. Each of the one or more ink head columns includes a plurality of ink heads that are arranged in a manner arranged along the main scanning direction and eject ink for image formation. When the head closest to one end side among the multiple ink heads, the pre-processing heads and the post-processing heads in the main scanning direction is the one end side head, the head closest to the other end side is the other end side head, the distance from the one end side head to the other end side head in the main scanning direction is LC, the distance from the one end side head to the pre-processing head in the main scanning direction is B1, and the distance from the one end side head to the post-processing head in the main scanning direction is B2, the pre-processing head and the post-processing head are configured in a manner that satisfies the relationship of Formula 2.

[0010] |(B1-B2) / LC|≤1 / 2 (Formula 2)

[0011] In addition, another aspect of the present invention relates to an inkjet recording method, which is an inkjet recording method of an inkjet recording device. The inkjet recording device includes a conveying unit, a carriage, one or more ink head arrays, a pre-processing head, and a post-processing head. The conveying unit conveys the recording medium along a prescribed conveying direction. The carriage moves back and forth along a main scanning direction intersecting the conveying direction. The one ink head array is mounted on the carriage at a prescribed position in the conveying direction. The multiple ink head arrays are mounted on the carriage in a manner arranged along the conveying direction. The pre-processing head is arranged on the upstream side of the one or more ink head arrays in the conveying direction, and ejects a non-colored pre-processing liquid. The post-processing head is arranged on the downstream side of the one or more ink head arrays in the conveying direction, and ejects a non-colored post-processing liquid. Each of the one or more ink head arrays includes a plurality of ink heads arranged in a manner arranged along the main scanning direction, each of which ejects ink for image formation. The inkjet recording method includes: assuming that among the plurality of ink heads, the pre-processing head, and the post-processing head, the head disposed closest to one end side in the main scanning direction is a one end side head, the head disposed closest to the other end side is a the other end side head, the distance from the one end side head to the other end side head in the main scanning direction is LC, the distance from the one end side head to the pre-processing head in the main scanning direction is B1, and the distance from the one end side head to the post-processing head in the main scanning direction is B2, and the following conditions are satisfied: 1 / 2≤(B1+B2) / LC≤3 / 2 The pre-processing head and the post-processing head are configured in a manner that shows the relationship of (Formula 1); while the slide is moved toward a first direction of the main scanning direction, the pre-processing liquid is ejected from the pre-processing head toward a specified recording area on the recording medium; while the recording medium is transported along the transport direction and the slide is moved along the main scanning direction, the ink is ejected from the ink head toward the recording area to which the pre-processing liquid has been ejected; while the recording medium is further transported along the transport direction and the slide is moved toward a second direction opposite to the first direction of the main scanning direction, the post-processing liquid is ejected from the post-processing head toward the recording area to which the ink has been ejected.

[0012] In addition, another aspect of the present invention relates to an inkjet recording method, which is an inkjet recording method of an inkjet recording device. The inkjet recording device includes a conveying unit, a carriage, one or more ink head arrays, a pre-processing head, and a post-processing head. The conveying unit conveys the recording medium along a prescribed conveying direction. The carriage moves back and forth along a main scanning direction intersecting the conveying direction. The one ink head array is mounted on the carriage at a prescribed position in the conveying direction. The multiple ink head arrays are mounted on the carriage in a manner arranged along the conveying direction. The pre-processing head is arranged on the upstream side of the one or more ink head arrays in the conveying direction, and ejects a non-colored pre-processing liquid. The post-processing head is arranged on the downstream side of the one or more ink head arrays in the conveying direction, and ejects a non-colored post-processing liquid. Each of the one or more ink head arrays includes a plurality of ink heads arranged in a manner arranged along the main scanning direction, each of which ejects ink for image formation. The inkjet recording method includes: assuming that among the plurality of ink heads, the pre-processing head, and the post-processing head, the head closest to one end side in the main scanning direction is a one end side head, the head closest to the other end side is a the other end side head, the distance from the one end side head to the other end side head in the main scanning direction is LC, the distance from the one end side head to the pre-processing head in the main scanning direction is B1, and the distance from the one end side head to the post-processing head in the main scanning direction is B2, so as to satisfy |(B1-B2) / LC|≤1 / 2 The pre-processing head and the post-processing head are configured in a manner in accordance with the relationship of (Formula 2); while the carriage is moved toward the first direction of the main scanning direction, the pre-processing liquid is ejected from the pre-processing head toward a specified recording area on the recording medium; while the recording medium is transported along the transport direction and the carriage is moved along the main scanning direction, the ink is ejected from the ink head toward the recording area to which the pre-processing liquid has been ejected; while the recording medium is further transported along the transport direction and the carriage is moved toward the first direction of the main scanning direction, the post-processing liquid is ejected from the post-processing head toward the recording area to which the ink has been ejected. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view showing the overall structure of an inkjet printer according to one embodiment of the present invention.

[0014] Figure 2 yes Figure 1 Schematic cross-sectional view along line II-II.

[0015] Figure 3 yes Figure 1 An enlarged perspective view of the carriage is shown.

[0016] Figure 4 It is a schematic diagram showing the serial printing method adopted in this embodiment.

[0017] Figure 5A It is a schematic diagram showing the printing status of the carriage on the forward path and the backward path.

[0018] Figure 5B This is a schematic diagram showing the printing status of the carriage on the forward and return paths.

[0019] Figure 6 This is a top view schematically showing the head configuration of Example 1. Figure 3 The arrangement of the ink head and the processing head in the carriage is shown.

[0020] Figure 7 Schematic diagram for explaining the landing timing of the pre-treatment liquid, ink, and post-treatment liquid at a point P on the recording medium.

[0021] Figure 8 This is a plan view of a carriage showing the head arrangement according to the second embodiment.

[0022] Figure 9 This is a plan view of a carriage showing the head arrangement according to the third embodiment.

[0023] Figure 10 This is a top view of a carriage showing the head arrangement according to the fourth embodiment.

[0024] Figure 11 It is a top view of a carriage showing the head arrangement according to the fifth embodiment.

[0025] Figure 12 It is a top view of a carriage showing the head arrangement according to the sixth embodiment.

[0026] Figure 13 Schematic diagram for explaining the landing timing of the pre-treatment liquid, ink, and post-treatment liquid at a point P on the recording medium.

[0027] Figure 14 It is a top view of a carriage showing the head arrangement according to the seventh embodiment.

[0028] Figure 15 It is a top view of a carriage showing the head arrangement according to the eighth embodiment.

[0029] Figure 16 It is a top view of a carriage showing the head arrangement according to the ninth embodiment.

[0030] Figure 17 This is a top view of a carriage showing the head arrangement according to the tenth embodiment.

[0031] Figure 18 This is a top view of a carriage showing the head arrangement according to Example 11.

[0032] Figure 19 It is a top view of a carriage showing the head arrangement according to Example 12.

[0033] Figure 20 It is a top view of a carriage showing the head arrangement according to the thirteenth embodiment.

[0034] Figure 21 It is a top view of a carriage showing the head arrangement involved in Example 14.

[0035] Figure 22 It is a top view of a carriage showing the head configuration involved in Example 15.

[0036] Figure 23 It is a top view of a carriage showing the head arrangement involved in Example 16.

[0037] Figure 24 It is a top view of a carriage showing the head arrangement and sub-tank arrangement according to Example 17.

[0038] Figure 25A Schematic diagram for explaining the case where a recording medium is conveyed at different conveyance pitches.

[0039] Figure 25B Schematic diagram for explaining the case where a recording medium is conveyed at different conveyance pitches.

[0040] Figure 26 It is a plan view of a carriage showing a head arrangement according to Comparative Example 1 for comparison with the present invention.

[0041] Figure 27 It is a plan view of a carriage showing a head arrangement according to Comparative Example 2 for comparison with the present invention. DETAILED DESCRIPTION

[0042] An embodiment of the present invention is described below with reference to the accompanying drawings. In this embodiment, an inkjet printer equipped with an ink head that ejects ink for image formation onto a wide and long recording medium is illustrated as a specific example of an inkjet recording device. The inkjet printer of this embodiment is suitable for digital printing, where images such as text and patterns are printed onto recording media made of materials such as woven and knitted fabrics using an inkjet method. Of course, the inkjet recording device of the present invention can also be used to print various inkjet images onto recording media such as paper and resin sheets.

[0043] [Overall structure of an inkjet printer]

[0044] Figure 11 is a perspective view showing the overall structure of an inkjet printer 1 according to an embodiment of the present invention. Figure 2 yes Figure 1 The inkjet printer 1 is a schematic cross-sectional view taken along line II-II. The inkjet printer 1 is a printer that prints images on a wide and long workpiece W (recording medium) using an inkjet method. The printer comprises a device frame 10, a workpiece transport unit 20 (transport unit) assembled to the device frame 10, and a carriage 3. In this embodiment, the left-right direction is the main scanning direction when printing on the workpiece W, and the direction from back to front is the sub-scanning direction (the transport direction F of the workpiece W).

[0045] The device frame 10 forms the framework for mounting the various components of the inkjet printer 1. The workpiece transport unit 20 is a mechanism for intermittently transporting the workpiece W so that it advances along a transport direction F from back to front within the printing area where the inkjet printing process is performed. The carriage 3 carries the ink head 4, pre-processing head 5, post-processing head 6, and auxiliary tank 7, and reciprocates in the left-right direction during the inkjet printing process.

[0046] The device frame 10 includes a central frame 111, a right frame 112, and a left frame 113. The central frame 111 forms the framework for mounting the various components of the inkjet printer 1 and has a width corresponding to the width of the workpiece conveyor 20. The right frame 112 and the left frame 113 are respectively disposed upright on the right and left sides of the central frame 111. Between the right frame 112 and the left frame 113 is the print area 12 where the workpiece W is printed.

[0047] The right frame 112 forms a maintenance area 13. The maintenance area 13 is where the carriage 3 retreats when the printing process is not in progress. The maintenance area 13 is used for cleaning and purging the nozzles (ejection holes) of the ink head 4, pre-processing head 5, and post-processing head 6, and is covered. The left frame 113 forms a turnaround area 14 for the carriage 3. The turnaround area 14 is where the carriage 3 temporarily enters during reverse main scanning, as it performs a main scan from right to left across the print area 12 during the printing process.

[0048] A carriage guide 15 is assembled above the device frame 10 to reciprocate the carriage 3 in the left-right direction. The carriage guide 15 is a flat, horizontally elongated member and is positioned above the workpiece conveyor 20. A timing belt 16 (moving member) is assembled on the carriage guide 15 so that it can rotate in the left-right direction (main scanning direction). The timing belt 16 is an endless belt that is driven by a drive source (not shown) to rotate in the left-right or right-hand direction.

[0049] A pair of upper and lower guide rails 17 are provided on the carriage guide 15, extending parallel to each other in the left-right direction. These guide rails serve as holding members for the carriage 3. The carriage 3 engages with the guide rails 17. Furthermore, the carriage 3 is secured to a timing belt 16. As the timing belt 16 rotates in the left or right direction, the carriage 3 is guided by the guide rails 17 and moves left or right along the carriage guide 15.

[0050] Main reference Figure 2 The workpiece conveying unit 20 includes a feed roller 21 for delivering the pre-printed workpiece W and a take-up roller 22 for taking up the printed workpiece W. The feed roller 21 is located at the lower rear portion of the device frame 10 and serves as the winding axis for the feed roll WA, which is the winding body for the pre-printed workpiece W. The take-up roller 22 is located at the lower front portion of the device frame 10 and serves as the winding axis for the take-up roll WB, which is the winding body for the printed workpiece W. The take-up roller 22 is attached to the first motor M1, which drives the take-up roller 22 to rotate about its axis and take up the workpiece W.

[0051] The path between the delivery roller 21 and the take-up roller 22 and through the print area 12 serves as the conveyance path for the workpiece W. This conveyance path is arranged, in order from the upstream side, with a first tension roller 23, a workpiece guide 24, a conveyance roller 25, a pinch roller 26, a return roller 27, and a second tension roller 28. The first tension roller 23 applies a predetermined tension to the workpiece W upstream of the conveyance roller 25. The workpiece guide 24 changes the conveyance direction of the workpiece W from upward to forward, allowing the workpiece W to enter the print area 12.

[0052] The transport roller 25 generates a conveying force that intermittently transports the workpiece W through the print area 12. Driven by the second motor M2, the transport roller 25 rotates about its axis, intermittently transporting the workpiece W forward (in the predetermined conveying direction F) so that the workpiece W passes through the print area 12 (image forming position) facing the carriage 3. The pinch roller 26 is positioned above the transport roller 25, forming a transport nip with the transport roller 25.

[0053] The folding roller 27 changes the conveyance direction of the workpiece W passing through the print area 12 from the forward direction to the downward direction, and guides the printed workpiece W to the take-up roller 22. The second tension roller 28 applies a predetermined tension to the workpiece W downstream of the conveying roller 25. In the print area 12, a platen 29 is arranged below the conveyance path of the workpiece W.

[0054] The carriage 3 reciprocates in a main scanning direction (in this embodiment, the left-right direction) that intersects (in this embodiment, is perpendicular to) the conveying direction F while being cantilevered by the guide rails 17. The carriage 3 includes a carriage frame 30, an ink head 4, a pre-processing head 5, a post-processing head 6, and a sub-tank 7 mounted on the carriage frame 30. The carriage frame 30 includes a head support frame 31 and a rear frame 32 (engaging portion).

[0055] The head support frame 31 is a horizontal plate that holds the heads 4 to 6 described above. The rear 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 rear frame 32. In addition, the guide rail 17 is engaged with the rear frame 32. That is, in this embodiment, the rear frame 32 is an engaging portion that is held by the guide rail 17 in a cantilevered state. The head support frame 31 is a horizontal plate whose rear end side is supported by the guide rail 17 in a cantilevered state via the engaging portion.

[0056] Furthermore, the cantilevered state indicates a state in which the engaging portion (rear frame 32) of the carriage 3 exists only on one side, upstream or downstream, from the center of the carriage 3 in the conveying direction F, and no other engaging portion exists on the opposite side of the engaging portion. The engaging portion is retained by the guide rail 17, which serves as a retaining member. The engaging portion may also be positioned outside the range where the ink head 4 and the processing head are positioned in the conveying direction F. In other words, the engaging portion may be positioned only upstream or downstream of the range where the ink head 4 and the processing head are positioned in the conveying direction F.

[0057] [Detailed structure of the carriage]

[0058] The carriage 3 will be further described. Figure 3 yes Figure 1 An enlarged perspective view of the carriage 3 is shown. Figure 3 , a conveyance direction F (sub-scanning direction) of the workpiece W and a main scanning direction S which is a moving direction of the carriage 3 are shown. Figure 3 The figure shows an example in which a plurality of ink heads 4 for ejecting ink for image formation onto a workpiece W, a pre-processing head 5 and a post-processing head 6 for ejecting a non-coloring processing liquid, and a plurality of auxiliary tanks 7 for supplying the ink and the processing liquid to these heads 4 to 6 are mounted on a slide 3.

[0059] Each ink head 4 includes: a plurality of nozzles (ink ejection holes) that eject ink droplets in an ejection manner, such as a piezoelectric manner using a piezoelectric element, a thermal manner using a heating element, and an ink channel that guides the ink to the nozzle. As the ink, for example, an aqueous pigment ink containing an aqueous solvent, a pigment, and a binder resin can be used. The plurality of ink heads 4 in this embodiment include first to sixth ink heads 4A to 4F that eject six different colors of ink, respectively. For example, the first ink head 4A ejects orange (second color) ink, the second ink head 4B ejects green (second color) ink, the third ink head 4C ejects yellow (first color) ink, the fourth ink head 4D ejects red (first color) ink, the fifth ink head 4E ejects blue (first color) ink, and the sixth ink head 4F ejects black (second color) ink.

[0060] The ink heads 4A to 4F of each color are mounted on the head support frame 31 of the carriage 3 in a manner arranged in the main scanning direction S. Each of the ink heads 4A to 4F of each color has two heads. For example, the first ink head 4A includes: an upstream head 4A1 arranged on the upstream side of the conveying direction F; and a downstream head 4A2 arranged at a position downstream relative to the upstream head 4A1 and offset to the left of the main scanning direction S. The same is true for the ink heads 4B to 4F of other colors. The upstream heads of these ink heads 4B to 4F are arranged in a row along the main scanning direction S at the same position as the upstream head 4A1 in the conveying direction F, and the downstream heads are arranged in a row along the main scanning direction S at the same position as the downstream head 4A2 in the conveying direction F.

[0061] The pre-processing head 5 and the post-processing head 6 are arranged at positions different from the ink head 4 in the conveying direction F. The pre-processing head 5 is arranged upstream of the ink head 4 in the conveying direction F. Figure 3 , an example is shown in which one pre-processing head 5 is arranged near the center of the array of ink heads 4. Similarly, the post-processing head 6 is arranged on the downstream side relative to the ink heads 4 in the conveying direction F. Figure 3 , an example is shown in which two post-processing heads 6A and 6B (a plurality of processing heads) are arranged near the center of the array of ink heads 4 along the main scanning direction S. Various arrangements of the ink heads 4, pre-processing heads 5, and post-processing heads 6 on the carriage 3 will be described in detail in Examples 1 to 17 described below.

[0062] As used in the above description, a series of heads formed by the ink head 4 and the post-processing head 6 along the main scanning direction S is referred to as a head column or simply a column. A head column may also include the pre-processing head 5. Furthermore, a series of heads formed by the ink head 4, the pre-processing head 5, and the post-processing head 6 along the conveying direction F is referred to as a head row or simply a row.

[0063] The pretreatment head 5 ejects a pretreatment liquid for performing a predetermined pretreatment on the workpiece W. The pretreatment liquid is ejected from the pretreatment head 5 toward a portion of the workpiece W where ink has not yet been ejected from the ink head 4. The pretreatment liquid is a non-colored treatment liquid that does not exhibit color even when adhered to the workpiece W. For example, the pretreatment liquid functions to improve the fixability of the ink to the workpiece W and the aggregation of the ink pigment. Examples of such pretreatment liquids include those containing a binder resin mixed in a solvent or those containing a positively charged cationic resin mixed in a solvent.

[0064] The post-processing head 6 ejects a post-processing liquid for implementing a prescribed post-processing onto the workpiece W to which the ink is attached. The post-processing liquid is ejected from the post-processing head 6 toward the position of the workpiece W after the ink is ejected from the ink head 4. The post-processing liquid is also a non-colored processing liquid that does not show color even if it adheres to the workpiece W. It is a processing liquid that plays a role in improving the fixability and firmness (resistance to friction and scratches) of the ink image printed on the workpiece W by the ink head 4. As such a post-processing liquid, a silicone-based processing liquid or the like can be used. In addition, the post-processing liquid and the pre-processing liquid are different processing liquids. Specifically, the components contained in the post-processing liquid and the pre-processing liquid are different.

[0065] Here, a non-colored treatment liquid refers to a treatment liquid whose coloration cannot be discerned by the naked eye when printed on a recording medium alone. The colors here include colors with a chroma of 0, such as black, white, and gray. A non-colored treatment liquid is basically a transparent liquid, but when observing 1L of the treatment liquid in its liquid state, for example, it is not completely transparent and sometimes appears slightly white. This color is very light, and when printed on a recording medium alone, the coloration cannot be discerned by the naked eye. In addition, depending on the type of treatment liquid, when printed on a recording medium alone, the recording medium may sometimes undergo changes such as gloss, but this state does not constitute coloration.

[0066] In this embodiment, the pre-treatment liquid and the post-treatment liquid may be sprayed onto substantially the entire surface of the workpiece W, or may be selectively sprayed like ink according to the image to be printed.

[0067] Next, we'll explain the selective ejection of pre-treatment liquid and post-treatment liquid. As described above, for portions of the workpiece W where the image is to be printed, pre-treatment liquid, ink, and post-treatment liquid are ejected in that order. In this case, the ink can be a single color or multiple colors. For portions where no color is to be printed, i.e., where no ink is to be ejected, pre-treatment liquid and post-treatment liquid are essentially not ejected. Furthermore, to adjust the quality of the printed image, the texture of the workpiece W, or other factors, the ejection of the pre-treatment liquid and post-treatment liquid can be selectively separated from the ejection of the ink.

[0068] The head support frame 31 has openings 31H at the head placement location. The ink heads 4A to 4F, the pre-processing head 5, and the post-processing head 6 are assembled to the head support frame 31 so as to fit into the respective openings 31H. The nozzles arranged on the lower end surfaces of the heads 4, 5, and 6 are exposed through the respective openings 31H.

[0069] The sub-tanks 7 are supported by the carriage 3 above the heads 4, 5, and 6 via a holding frame (not shown). The sub-tanks 7 are provided corresponding to the heads 4, 5, and 6, respectively. Ink or processing liquid is supplied to each sub-tank 7 from an ink cartridge or main tank (not shown) containing ink and processing liquid. Each sub-tank 7 supplies the ink or processing liquid to each head 4, 5, and 6. Each sub-tank 7 and the heads 4, 5, and 6 are connected to each other. Figure 3 Through the pipeline (not shown) Figure 24 P1, P2, P3) shown in are connected.

[0070] As described above, the inkjet printer 1 of this embodiment is a multifunction all-in-one printer equipped with three heads: an ink head 4, a pre-processing head 5, and a post-processing head 6, mounted on a single carriage 3. This inkjet printer 1 can, for example, perform both the pre-processing liquid and post-processing liquid ejection steps during the printing process of inkjet printing on a material in digital printing. This simplifies the printing process and reduces the size of the printing apparatus.

[0071] [Print Method]

[0072] Next, a description will be given of a printing method performed by the inkjet printer 1 according to this embodiment. The inkjet printer 1 performs a printing process on the workpiece W using a serial printing method. Figure 4 : is a schematic diagram showing the serial printing method. Figure 4 In FIG, the pre-processing head 5 and the post-processing head 6 are omitted and the carriage 3 is simply drawn.

[0073] 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 that repeatedly performs the reciprocating movement of the carriage 3 carrying the ink heads 4 of each color in the main scanning direction S and the intermittent feeding of the workpiece W in the feeding direction F. Here, it is assumed that the ink head 4 has a predetermined printing width Pw in the feeding direction F. The printing width Pw is approximately equal to the arrangement range of the ink ejection nozzles of the ink head 4. In addition, Figure 4 And the following description Figure 5A 、 Figure 5B In FIG, the width of each head in the conveying direction F is drawn to be substantially equal to the printing width Pw. In reality, the width of each head in the conveying direction F is larger than the printing width Pw and the arrangement range of the ejection nozzles.

[0074] Figure 4The figure shows the state where the carriage 3 moves in the outward direction SA of the main scanning direction S and the printing of the strip image G1 with the printing width Pw is completed. When the main scanning is performed in the outward direction SA, the conveyance of the workpiece W stops. After printing the strip image G1, the workpiece W is sent in the conveying direction F by a spacing equivalent to the printing width Pw. At this time, the carriage 3 waits in the folding area 14 on the left end side. After sending out the workpiece W, the carriage 3 folds back in the return direction SB as the synchronous belt 16 rotates in the reverse direction. The workpiece W is in a stopped state. Then, as shown Figure 4 As shown, the carriage 3 moves in the return path direction SB and prints a band-like image G2 having a print width Pw on the upstream side of the band-like image G1. Thereafter, the same operation is repeated.

[0075] Figure 5A and Figure 5B It is a schematic diagram showing the printing status of the carriage 3 on the forward and return paths. Here, the ink head 4, the pre-processing head 5 and the post-processing head 6 mounted on the carriage 3 are simplified. The ink head 4 includes the first, second, third and fourth ink heads 4A, 4B, 4C and 4D for ejecting inks of the first, second, third and fourth colors that are different from each other. These first to fourth ink heads 4A to 4D are arranged in a row along the main scanning direction S. The pre-processing head 5 is arranged on the upstream side of the conveying direction F of the ink head 4, and the post-processing head 6 is arranged on the downstream side. In addition, as in Figure 4 Similarly to the situation described in , the workpiece W is fed along the conveying direction F between the forward printing and the return printing. The travel distance in the conveying direction F at this time is the spacing between adjacent heads in the conveying direction F (head pitch). In addition, this travel distance is also the printing width of each head 4, 5, and 6.

[0076] Figure 5A Figure 3 shows a state where the carriage 3 is performing a printing operation (forward main scan) while moving in the forward direction SA of the main scanning direction S. Area A4 on the workpiece W is the area facing the pre-processing head 5 mounted on the upstream side of the carriage 3. During this forward main scan, the pre-processing liquid ejected from the pre-processing head 5 forms a pre-processing layer Lpre on area A4.

[0077] Area A3 is an area with a distance of one head spacing on the downstream side relative to area A4, and is the area faced by the ink head 4. On area A3, a pre-processing layer Lpre has been formed along the entire length in the main scanning direction by the previous return path main scan. In this outward main scan, on the pre-processing layer Lpre of area A3, the first, second, third, and fourth ink layers LCA, LCB, LCC, and LCD are formed by the first to fourth color inks ejected in sequence according to the arrangement order of the first to fourth ink heads 4A to 4D. In addition, for ease of understanding, Figure 5AIn the figure, the fourth to first ink layers LCD to LCA are sequentially stacked, but they are not actually stacked. In addition, the aforementioned pre-processing layer Lpre and the post-processing layer Lpos described later are not formed on the workpiece W.

[0078] Area A2 is located downstream of area A3 by a distance of one head pitch and faces the post-processing head 6, mounted on the most downstream side of the carriage 3. Area A2 has already been formed along its entire length in the main scanning direction with the pre-processing layer Lpre formed by the previous outward main scan and the first to fourth ink layers LCA to LCD formed by the previous return main scan. During this outward main scan, the post-processing liquid ejected from the post-processing head 6 forms a post-processing layer Lpos on the first to fourth ink layers LCA to LCD in area A2.

[0079] Area A1 is located downstream of area A2 by a distance of one head pitch and is the area where the carriage 3 passes through and the printing process ends. Specifically, in area A1, the pre-processing layer Lpre, the first to fourth ink layers LCA to LCD, and the post-processing layer Lpos are formed over the entire length in the main scanning direction.

[0080] Figure 5B Indicates the end Figure 5A After the outward main scan, the carriage 3 turns back and moves in the return direction SB while performing the return main scan. Before this turnaround, the workpiece W is fed a distance of one head pitch in the conveyance direction F. Area A5 on the workpiece W is located 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.

[0081] In areas A4 and A3, the first to fourth ink layers LCA to LCD and the post-processing layer Lpos are formed on the existing layers, respectively. Specifically, in area A4, the first to fourth ink layers LCA to LCD are formed on the pre-processing layer Lpre. In area A3, the post-processing layer Lpos is formed on the first to fourth ink layers LCA to LCD. Area A2 is the area where the printing process ends after area A1.

[0082] The reason why printing processing can be performed on both the outward main scan and the return main scan as described above is that the pre-processing head 5 and the post-processing head 6 are offset and arranged relative to the ink head 4 in the conveying direction F. Assuming that the pre-processing head 5, the ink head 4, and the post-processing head 6 are arranged in a row in this order along the main scanning direction S on the slide 3, the printing processing that can make the pre-processing liquid and the post-processing liquid fall in the desired order can only be achieved on one side of the outward main scan or the return main scan. In order to be able to perform printing processing in both directions, a pair of pre-processing heads 5 and post-processing heads 6 must be arranged on both sides of the arrangement body of the ink head 4. At this time, the width of the slide 3 in the main scanning direction S becomes large. Since such a configuration is not required in the present embodiment, the width of the slide 3 in the main scanning direction S can be miniaturized.

[0083] Furthermore, providing multiple rows of ink heads 4 can increase the amount of ink deposited 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 through fourth ink layers LCA through LCD as described above, the workpiece W is transported in the transport direction F by a distance equal to the head pitch, and the second row of ink heads 4 forms the first through fourth ink layers LCA through LCD. This allows two layers of ink to be printed on the workpiece W.

[0084] [Various ways to configure the header]

[0085] Hereinafter, various configuration examples of the ink head 4, the pre-processing head 5, and the post-processing head 6 on the carriage 3 will be described as examples 1 to 17. Figures 1 to 5A 、 Figure 5B This figure is used to explain the basic functions of the pre-processing head 5 and the post-processing head 6. The detailed configuration of the pre-processing head 5 and the post-processing head 6 involved in this embodiment will be described in the following. Figure 6 This will be explained later.

[0086] <Example 1>

[0087] Figure 6 This is a plan view schematically showing the head configuration according to the first embodiment. Figure 6 Or it means Figure 3FIG. 4 is a diagram showing the arrangement of the ink head 4 and the pre-processing head 5 and the post-processing head 6 (a plurality of processing heads) on the carriage 3. The carriage 3 is supported by the guide rail 17 in a cantilevered state at the rear frame 32 (engaging portion). The rear frame 32 is arranged on the upstream side of the conveying direction F of the head support frame 31. In the conveying direction F, the side of the head support frame 31 on which the rear frame 32 is arranged is referred to as the base end side 311, and the side of the head support frame 31 opposite to the base end side 311 is referred to as the distal end side 312. As already mentioned, the head support frame 31 of the carriage 3 is equipped with the first to sixth ink heads 4A to 4F, the pre-processing head 5, and the post-processing head 6, which respectively eject six different colors of ink. Each of the ink heads 4A to 4F of each color has two (a total of 12) unit heads. There is one pre-processing head 5, and two post-processing heads 6.

[0088] The group of first to sixth ink heads 4A to 4F constituting the ink head 4 is arranged so as to be aligned along the main scanning direction S in the central region of the head support frame 31 in the conveying direction F. The pre-processing head 5 is positioned approximately in the center of the carriage 3 in the main scanning direction S, upstream of the ink heads 4 in the conveying direction F, and on the base end 311 of the head support frame 31. On the other hand, the post-processing head 6 is positioned approximately in the center of the carriage 3 in the main scanning direction S, downstream of the ink heads 4 in the conveying direction F, and on the distal end 312 of the head support frame 31. Both the pre-processing head 5 and the post-processing head 6 are positioned near the center of the head support frame 31 in the main scanning direction S.

[0089] The first ink head 4A includes: an upstream head 4A1; and a downstream head 4A2 arranged on the downstream side relative to the upstream head 4A1. That is, the upstream head 4A1 and the downstream head 4A2 are arranged in the conveying direction F. The upstream head 4A1 is arranged at a position close to the base end side 311 in the central area of the head support frame 31. The downstream head 4A2 is arranged at a position close to the distal end side 312 in the central area of the head support frame 31. Relative to the upstream head 4A1, the downstream head 4A2 is arranged at a position offset toward one side (left side) in the main scanning direction S and partially overlapped in the conveying direction F. Of course, the upstream head 4A1 and the downstream head 4A2 can also be arranged at the same position in the main scanning direction S (positions arranged in a straight line in the conveying direction F). However, the configuration of this embodiment can make the size of the carriage 3 in the conveying direction F smaller.

[0090] Furthermore, by such an arrangement, the ink heads 4 that eject ink of a single color are arranged collectively in the main scanning direction S. Specifically, all the ink heads 4 mounted on the carriage 3 that eject ink of a single color are arranged so that no ink heads 4 that eject ink of other colors are sandwiched between them in the main scanning direction S. Alternatively, all the ink heads 4 mounted on the carriage 3 that eject ink of a single color may be arranged within a predetermined range, and no ink heads 4 that eject ink of other colors may be arranged within that range.

[0091] If there are differences in printing conditions such as landing position and ejection volume between the two ink heads 4, there is a higher probability that the difference will be noticeable when the two ink heads 4 eject the same color, compared to when the two ink heads 4 eject different colors. If the ink heads 4 ejecting the same color are arranged together in the main scanning direction S, even if there are differences in printing conditions between the ink heads 4, the quality of the printed image can be minimized.

[0092] The second to sixth ink heads 4B to 4F also include upstream heads 4B1, 4C1, 4D1, 4E1, and 4F1, and downstream heads 4B2, 4C2, 4D2, 4E2, and 4F2, similar to the upstream head 4A1 and downstream head 4A2 described above. The upstream heads 4A1 to 4F1 of the first to sixth ink heads 4A to 4F are arranged in a row at predetermined intervals along the main scanning direction S at the same position in the conveying direction F. Furthermore, the downstream heads 4A2 to 4F2 are also arranged in a row at predetermined intervals along the main scanning direction S at the same position in the conveying direction F. As a result, a zigzag arrangement is formed, with portions of the downstream heads 4A2 to 4F2 intersecting the respective arrangement intervals of the upstream heads 4A1 to 4F1.

[0093] In other words, the structure of the ink head 4 is described. The ink head 4 includes a plurality of ink head arrays mounted on the carriage 3 in an array along the transport direction F. Each of the plurality of ink head arrays includes a plurality of ink heads arranged in an array along the main scanning direction S and each ejecting ink for image formation. Figure 6 In the illustrated example, the plurality of ink head arrays include a first ink head array 41 and a second ink head array 42. The ink heads included in the first ink head array 41 are upstream heads 4A1, 4B1, 4C1, 4D1, 4E1, and 4F1. The ink heads included in the second ink head array 42 are downstream heads 4A2, 4B2, 4C2, 4D2, 4E2, and 4F2.

[0094] The preprocessing head 5 is arranged so that a portion thereof enters between a pair of ink heads adjacent to each other in the main scanning direction S. Specifically, the downstream portion of the preprocessing head 5 enters between the upstream head 4C1 of the third ink head 4C and the upstream head 4D1 of the fourth ink head 4D.

[0095] The post-processing head 6 includes a first post-processing head 6A and a second post-processing head 6B arranged in parallel in the main scanning direction S. Figure 6 ] shows an example in which the first and second post-processing heads 6A and 6B are arranged at the same position in the conveying direction F, spaced apart along the main scanning direction S at predetermined intervals. The first post-processing head 6A is positioned so that its upstream portion extends between the downstream head 4C2 of the third ink head 4C and the downstream head 4D2 of the fourth ink head 4D. The second post-processing head 6B is positioned so that its upstream portion extends between the downstream head 4D2 and the downstream head 4E2, and is positioned at the same position in the main scanning direction S as the upstream head 4D1. With this arrangement, the first and second post-processing heads 6A and 6B overlap with the downstream heads 4C2, 4D2, and 4E2 in the conveying direction F, with an area fa therebetween.

[0096] In the transport direction F, the width of each head is larger than the printing width Pw and the arrangement range of the ejection nozzles. Therefore, the heads are arranged to have an overlapping area fa so that there is no gap between the printing width Pw of each row of heads and the printing range Pw of the adjacent row of heads.

[0097] In addition, unless otherwise specified, Figure 6 In the figures, the intervals between adjacent heads (the intervals between the centers of the heads) are the same in the main scanning direction S. Similarly, the distances between adjacent heads (the intervals between the centers of the heads) in the conveying direction F are the same.

[0098] As a result of the above-described head arrangement, the pre-processing head 5 and the post-processing head 6 are arranged within the arrangement width H of the ink head 4 in the main scanning direction S. The ink head 4 has an arrangement width H between the downstream head 4A2 of the first ink head 4A and the upstream head 4F1 of the sixth ink head 4F in the main scanning direction S. The pre-processing head 5 is arranged within the arrangement width H on the upstream side of the ink head 4, and the post-processing head 6 is arranged within the arrangement width H on the downstream side of the ink head 4.

[0099] According to the head configuration involved in the embodiment 1 described above, it is possible to achieve both miniaturization of the carriage 3 and increase the necessary amount of ink and treatment liquid ejected. That is, the pre-processing head 5 and the post-processing head 6 are arranged at a different position from the ink head 4 in the conveying direction F. According to this configuration, the ink heads 4A to 4F that can eject the necessary amount of ink are arranged in the main scanning direction S, and can perform printing processing in both the outgoing main scanning and the return main scanning, and the width of the carriage required for carrying the above-mentioned heads 4 to 6 in the main scanning direction can be shortened. Moreover, the post-processing head 6 is composed of a plurality of first and second post-processing heads 6A and 6B, and they are arranged in the main scanning direction S. Therefore, if the ejection amount of the post-processing liquid is insufficient if a single head is used, the necessary amount can be ejected by configuring a plurality of post-processing heads 6A and 6B.

[0100] The first to sixth ink heads 4A to 4F include upstream heads 4A1 to 4F1 (a first ink head row 41) and downstream heads 4A2 to 4F2 (a second ink head row 42), arranged along the transport direction F (a direction intersecting the arrangement direction of the multiple processing heads). Therefore, even if the number of ink heads 4 is increased to increase the amount of ink ejected per color or to achieve multi-color printing, the width of the carriage 3 in the main scanning direction can be prevented from being increased.

[0101] The pre-processing head 5 and the post-processing head 6 are arranged within the arrangement width H of the first to sixth ink heads 4A to 4F in the main scanning direction S. Therefore, even when the carriage 3 carries the pre-processing head 5 and the post-processing head 6 in addition to the ink heads 4, there is no need to increase the width of the carriage 3 in the main scanning direction. In other words, the width of the carriage 3 in the main scanning direction can be reduced.

[0102] The pre-processing heads 5 and post-processing heads 6 are arranged so that portions of them extend between the arrangement intervals of the first to sixth ink heads 4A to 4F. Focusing on the first post-processing head 6A, a portion of the first post-processing head 6A extends between the pair of downstream heads 4C2 and 4D2. This zigzag arrangement allows for high-density arrangement of the ink heads 4 and the processing heads 5 and 6, which are positioned at different locations in the conveying direction F. Consequently, the width of the carriage 3 in the conveying direction F can be reduced.

[0103] In the head arrangement of Example 1, one pre-processing head 5 is positioned upstream of the ink head 4 in the transport direction F, and two post-processing heads 6A and 6B are positioned downstream. This provides a multifunctional, all-in-one inkjet printer 1 in which three heads—those for discharging pre-processing liquid, ink, and post-processing liquid—are mounted on a single carriage 3. Furthermore, because the pre-processing head 5, ink head 4, and post-processing head 6 are sequentially positioned in the transport direction F, the pre-processing liquid, ink, and post-processing liquid can be discharged in a desired landing order during both the forward and return main scanning phases.

[0104] The carriage 3 also includes a rear frame 32 (engaging portion) held in a cantilevered position by the guide rail 17 (holding member). By supporting the carriage 3 in a cantilevered position on the timing belt 16, the structure can be simplified. Furthermore, by supporting the carriage 3 in a cantilevered position, it is easy to open the downstream side of the carriage 3, making maintenance of the ink head 4 and the processing heads 5 and 6 easier.

[0105] In the carriage 3 supported in a cantilevered state, the pre-processing head 5 is positioned on the base end side 311 (the side close to the engaging portion) of the head support frame 31, and the post-processing head 6 is positioned on the distal end side 312 (the side away from the engaging portion). Unlike the base end side 311 of the rear frame 32, which is fixed to the timing belt 16, the distal end side 312, which serves as the free end, is estimated to have a lower positioning accuracy. However, the distal end side 312 is equipped with the post-processing head 6, which does not require relatively high ejection accuracy. Since the post-processing liquid covers the ink image printed on the workpiece W, even if a landing position shift occurs, the relative impact on image quality can be reduced compared to the same degree of landing position shift of the pre-processing liquid. Therefore, even when using a carriage 3 supported in a cantilevered state, image quality can be less likely to degrade.

[0106] <Problems with header configuration>

[0107] As described above, in addition to the ink head 4, the pre-treatment head 5 for ejecting the pre-treatment liquid and the post-treatment head 6 for ejecting the post-treatment liquid are respectively mounted on the carriage 3. As the carriage 3 reciprocates in the main scanning direction, the pre-treatment liquid, ink, and post-treatment liquid are sequentially ejected onto the workpiece W. The time from the landing of the pre-treatment liquid to the landing of the post-treatment liquid varies depending on the position of the image in the main scanning direction S. As a result, there is a problem that the image quality on the workpiece W is likely to vary.

[0108] For example, when using a pre-treatment liquid that enhances the aggregation of ink pigments, the longer the time from the landing of the pre-treatment liquid to the landing of the ink, the darker the color. Similarly, when using a post-treatment liquid that enhances fastness, the longer the time from the landing of the ink to the landing of the post-treatment liquid, the darker the color. When printing using these liquids, the longer the time from the landing of the pre-treatment liquid to the landing of the post-treatment liquid, the darker the color. Therefore, by reducing the variation in the time from the landing of the pre-treatment liquid to the landing of the post-treatment liquid, it is possible to reduce the difference in color density.

[0109] Even if the time from the landing of the pre-treatment liquid to the landing of the post-treatment liquid is the same, if there is a difference in the ratio between the time from the landing of the pre-treatment liquid to the landing of the ink and the time from the landing of the pre-treatment liquid to the landing of the post-treatment liquid, the color density is not necessarily the same. However, if the time range from the landing of the pre-treatment liquid to the landing of the post-treatment liquid is shortened, the color density range can be narrowed.

[0110] To address the aforementioned issues, the present inventors have discovered that by appropriately configuring the pre-processing head 5 and the post-processing head 6 on the carriage 3, the time variation from the time the pre-processing liquid lands to the time the post-processing liquid lands can be reduced, even between different image positions in the main scanning direction S. Specifically, the present inventors have discovered that by appropriately configuring the pre-processing head 5 and the post-processing head 6 based on the relationship between the movement direction of the carriage 3 when the pre-processing head 5 ejects the pre-processing liquid and the movement direction of the carriage 3 when the post-processing head 6 ejects the post-processing liquid—in other words, based on the number of ink head arrays comprising the ink head 4 and the transport pitch of the workpiece W—the time variation from the time the pre-processing liquid lands to the time the post-processing liquid lands can be reduced. The following describes the concept of head configuration based on this new concept and an example configuration (embodiment).

[0111] <Header Configuration Idea 1>

[0112] Figure 7 Schematic diagram for explaining the landing time of the pre-treatment liquid, ink and post-treatment liquid at point P on the workpiece W. Figure 7 In the figure, the printing area 12 is arranged in the center, and the maintenance area 13 and the return area 14 are arranged on the left and right sides thereof. As described above, the carriage 3 moves between the maintenance area 13 and the return area 14 along the main scanning direction S, thereby ejecting ink, pre-treatment liquid, and post-treatment liquid from the ink head 4, the pre-treatment head 5, and the post-treatment head 6 to the workpiece W. In addition, Figure 7 , for ease of explanation, the carriage 3 is shown in both the maintenance area 13 and the return area 14. The following describes a case where the ink head 4 includes a plurality of ink head rows having an even number of rows, and the workpiece W is intermittently transported and printed at a head pitch (the spacing between adjacent heads in the transport direction F). Specifically, the description describes a case where the movement direction of the carriage 3 when the pre-processing head 5 ejects a pre-processing liquid onto the workpiece W differs from the movement direction of the carriage 3 when the post-processing head 6 ejects a post-processing liquid.

[0113] exist Figure 7In the figure, among the multiple ink heads, pre-processing head 5 and post-processing head 6 included in the multiple ink head arrays 41 and 42, the head closest to one end side in the main scanning direction S is the one end side head, the head closest to the other end side is the other end side head, the distance from the one end side head to the other end side head in the main scanning direction S is LC, the distance from the one end side head to the pre-processing head 5 in the main scanning direction S is B1, and the distance from the one end side head to the post-processing head 6 in the main scanning direction S is B2. Figure 7 In the example shown, the head at one end is the downstream head 4A2 of the first ink head 4A, and the head at the other end is the upstream head 4F1 of the sixth ink head 4F. The distances LC, B1, and B2 can be set based on a portion of each head. However, in the following description, the aforementioned distances are set based on the center of each head in the main scanning direction S. Furthermore, the aforementioned heads at one end and the heads at the other end can also be reversed. The center of a head in the main scanning direction S is essentially the position of an imaginary line perpendicular to the main scanning direction S that bisects the area of a flat shape when the head is viewed from above. Depending on the situation, when viewed from the head, the position of an imaginary line perpendicular to the main scanning direction S that bisects the area of the smallest convex polygon containing all the ejection nozzles of the head can be used as the center of the head in the main scanning direction S.

[0114] First, the timing for each liquid to land on point P on workpiece W within print area 12 will be described. Since the speed of carriage 3 is constant, the following description uses distances. The actual timing can be calculated by dividing each distance by the speed of carriage 3. It is assumed that point P is located at a distance A from the end of print area 12 on the maintenance area 13 side.

[0115] Furthermore, it is assumed here that the liquid from each head is ejected from the center in the main scanning direction S. If the nozzles of each head are actually distributed diffusely in the main scanning direction S, this dispersion will also affect the landing time. However, because the positional differences between nozzles within a head in the main scanning direction S are smaller than the positional differences between nozzles in different heads in the main scanning direction S, the influence of the head arrangement can be estimated by taking this into account as described above.

[0116] In addition, for the sake of easy understanding, the landing time and the ejection time are assumed to be the same for explanation. In fact, the time of ejection so that the liquid lands at a predetermined position at a predetermined time is earlier than the landing time, which is the flight time of the liquid from the head to the workpiece W.

[0117] Assume that the one-way travel distance of the carriage 3 (the distance from the maintenance area 13 to the turnaround area 14) is the minimum distance LP + LC required for printing, and the carriage 3 is positioned in the maintenance area 13 as its initial position. In this case, during the first movement (leftward movement) of the carriage 3 from the maintenance area 13 to the turnaround area 14, the time T1 for the pretreatment liquid ejected from the pretreatment head 5 to land at point P can be expressed as a distance using the following equation A.

[0118] T1=A+B1 (Formula A)

[0119] After the pretreatment liquid lands on the point P, in the second movement operation (movement in the right direction) of the carriage 3 moving from the turn-back area 14 to the maintenance area 13, ink is ejected from each ink head of the first head row 41 toward the point P. Furthermore, in the third movement operation (movement in the left direction) of the carriage 3 further moving from the maintenance area 13 to the turn-back area 14, ink is ejected from each ink head of the second head row 42 toward the point P.

[0120] Furthermore, in the fourth movement operation (rightward movement) of the carriage 3 from the turnaround area 14 to the maintenance area 13, the time T2 for the post-processing liquid ejected from the post-processing head 6 to land at point P can be expressed by the following equation B. Equation B includes the times of the first to third movement operations.

[0121] T2=LP-A+LC-B2+3×(LP+LC)(Formula B)

[0122] As a result, the time ΔT from the time the pre-treatment liquid lands at point P to the time the post-treatment liquid lands can be expressed by the following formula C.

[0123] ΔT=T2-T1=LP-2A+LC-(B1+B2)+3×(LP+LC) (Formula C)

[0124] Here, all points on the workpiece W in the printing area 12 are studied. Since the distance A can be considered to vary from 0 to LP, the range involved in ΔT in the above formula C can be expressed by the following formulas D, E, and F.

[0125] ΔTmin1≤ΔT≤ΔTmax1 (Formula D)

[0126] ΔTmin1=-LP+LC-(B1+B2)+3×(LP+LC) (Formula E)

[0127] ΔTmax1=LP+LC-(B1+B2)+3×(LP+LC) (Formula F)

[0128] Meanwhile, during printing on a workpiece W, the carriage 3 may first move from the turnaround area 14, i.e., rightward as a first movement. In this case, as described above, the time ΔT from the time the pre-treatment liquid lands at point P to the time the post-treatment liquid lands can be expressed by the following equation G.

[0129] ΔT=2A-LP-(LC-(B1+B2))+3×(LP+LC) (Formula G)

[0130] At this time, all points on the workpiece W in the printing area 12 are studied. Since the distance A can be considered to change from 0 to LP, the range involved in ΔT in the above formula G can be expressed by the following formulas H, I, and J.

[0131] ΔTmin2≤ΔT≤ΔTmax2 (Formula H)

[0132] ΔTmin2=-LP-(LC-(B1+B2))+3×(LP+LC) (Formula I)

[0133] ΔTmax2=LP-(LP-(B1+B2))+3×(LP+LC) (Formula J)

[0134] According to the above description, the situation where the slide 3 moves from either the maintenance area 13 or the return area 14 is also taken into consideration. According to the above-mentioned Formulas D to F and H to J, the time ΔT from the time the pre-treatment liquid lands at point P to the time the post-treatment liquid lands is distributed within the range of the following Formula K.

[0135] -LP-|(LC-(B1+B2))|+3×(LP+LC)≤ΔT≤LP+|(LC-(B1+B2))|+3×(LP+LC)(Formula K)

[0136] Studying the above-mentioned equation K reveals that in order to reduce the distribution range ΔT of the time from the landing of the pre-treatment liquid to the landing of the post-treatment liquid across the entire area of the workpiece W in the main scanning direction S, the pre-treatment head 5 and the post-treatment head 6 on the carriage 3 can be arranged so that the absolute value of LC - (B1 + B2) is minimized. In other words, the most preferred configuration satisfies the relationship LC = B1 + B2. Furthermore, the inventors have conducted repeated research, experiments, and investigations, and have discovered that satisfying the following equation 1 can reduce the variation in the time from the landing of the pre-treatment liquid to the landing of the post-treatment liquid on the workpiece W, thereby achieving stable image formation.

[0137] 1 / 2≤(B1+B2) / LC≤3 / 2 (Formula 1)

[0138] Formula 1 indicates that B1+B2 is within the range of 0.5 to 1.5 times LC. When only the landing time is considered, as described above, it is most preferable that B1+B2 matches LC.

[0139] Based on the above ideas, Figure 6 In the head configuration shown in Example 1, the distance LC from the downstream head 4A2 of the first ink head 4A to the upstream head 4F1 of the sixth ink head 4F in the main scanning direction S is 11, the distance B1 from the downstream head 4A2 to the pre-processing head 5 in the main scanning direction S is 6, and the distance B2 from the downstream head 4A2 to each post-processing head 6 in the main scanning direction S is 5 or 7. (B1 + B2) / LC is 1 or 1.18, indicating that any distance B2 satisfies the above equation 1. Therefore, regardless of the direction of movement of the carriage 3, the difference in time from the landing of the pre-processing liquid to the landing of the post-processing liquid can be reduced. As a result, the pre-processing liquid, ink, and post-processing liquid can be stably and sequentially landed on the workpiece W, reducing the occurrence of image quality differences on the workpiece W.

[0140] In addition, if Figure 6 When at least one of the pre-processing heads 5 and the post-processing heads 6 is provided in plurality, it is preferred that at least one of the plurality of heads is provided so as to satisfy Formula 1. As described above, by providing at least one processing head so as to satisfy Formula 1, not only can the time difference between the landing of the pre-processing liquid and the landing of the post-processing liquid be reduced, but also the amount of the processing liquid that can be discharged can be increased because the processing liquid can also be discharged from the other processing heads.

[0141] Furthermore, it is further preferred that all of the plurality of heads are arranged to satisfy Expression 1. In this case, the time difference from the landing of the pre-treatment liquid to the landing of the post-treatment liquid can be further reduced, and the amount of the treatment liquid that can be discharged can be increased.

[0142] <Example 2>

[0143] also, Figure 8 This is a top view of carriage 3A showing the head arrangement according to Example 2. In Example 2, pre-processing head 5 is located at the left end of the array of all heads, and post-processing head 6 is located at the right end of the array. In this head arrangement, LC = 11, B1 = 0, B2 = 11, and (B1 + B2) / LC = 1, satisfying the above-mentioned equation 1.

[0144] <Example 3>

[0145] also, Figure 9This is a top view of the carriage 3B showing the head arrangement according to Example 3. In Example 3, the pre-processing head 5 and the post-processing head 6 are positioned approximately in the center of the head array in the main scanning direction S. In this head arrangement, LC = 11, B1 = 6, B2 = 5, and (B1 + B2) / LC is 1, satisfying the above-mentioned equation 1.

[0146] <Example 4>

[0147] also, Figure 10 This is a top view of the carriage 3C showing the head arrangement according to Example 4. In Example 4, the pre-processing head 5 is located near the right end of the array of all heads, and the post-processing head 6 is located approximately in the center of the array in the main scanning direction S. In this head arrangement, LC = 11, B1 = 10, B2 = 5, and (B1 + B2) / LC is 1.36, which satisfies the above-mentioned equation 1.

[0148] <Example 5>

[0149] also, Figure 11 3D is a top view showing the head configuration according to Example 5. In this head configuration, LC = 13, B1 = 0, B2 = 13, (B1 + B2) / LC is 1, and it is known that the above-mentioned formula 1 is satisfied. Figure 11 As shown, the pre-processing head 5 may be arranged on one end side of the ink head 4 in the main scanning direction S, and the post-processing head 6 may be arranged on the other end side of the ink head 4 in the main scanning direction S.

[0150] <Example 6>

[0151] also, Figure 12 : is a top view of the carriage 3E showing the head configuration according to Example 6. In this head configuration, LC=5, B1=5, B2=0, (B1+B2) / LC is 1, and it is known that the above-mentioned formula 1 is satisfied. Figure 12 As shown, the first ink head row 41 and the second ink head row 42 are not limited to a zigzag arrangement, and may be arranged at intervals in the transport direction F. The pre-processing head 5 and the post-processing head 6 are also not limited to a zigzag arrangement, and may be arranged at intervals on the upstream and downstream sides of the transport direction F of the ink head 4.

[0152] <Header Configuration Idea 2>

[0153] Figure 13 and Figure 7This is also a schematic diagram for explaining the landing time of the pre-treatment liquid, ink, and post-treatment liquid at the point P on the workpiece W. In addition, the following describes a case where the ink head 4 has an odd number of ink head rows, and the movement direction of the carriage 3 when the pre-treatment head 5 ejects the pre-treatment liquid onto the workpiece W is the same as the movement direction of the carriage 3 when the post-treatment head 6 ejects the post-treatment liquid. Figure 7 The description of the same contents will be omitted. Figure 13 In FIG, the ink head 4 has one ink head array (first ink head array 41). Figure 13 In the illustrated example, the head on one end side is the first ink head 4A, and the head on the other end side is the sixth ink head 4F.

[0154] like Figure 13 As shown, when the ink head 4 has an odd number of ink head rows and the workpiece W is intermittently transported and printed with a head pitch (the spacing between adjacent heads in the transport direction F), the movement direction (main scanning direction) of the carriage 3 when the pre-processing head 5 ejects the pre-processing liquid is the same as the movement direction of the carriage 3 when the post-processing head 6 ejects the post-processing liquid. Therefore, the time Δ from the landing of the pre-processing liquid to the landing of the post-processing liquid does not depend on the position of the point P in the main scanning direction S.

[0155] Specifically, in the first movement operation (leftward movement) of the carriage 3 from the maintenance area 13 to the turn-back area 14 , the time T1 at which the pretreatment liquid discharged from the pretreatment head 5 lands at the point P can be expressed by the following formula L.

[0156] T1=A+B1 (Formula L)

[0157] After the pretreatment liquid lands on the dot P, ink is ejected from each ink head of the first head array 41 toward the dot P in the second movement operation (rightward movement) of the carriage 3 from the turnaround area 14 to the maintenance area 13 .

[0158] Furthermore, in the third movement operation (leftward movement) of the carriage 3 from the maintenance area 13 to the turn-back area 14 , time T2 when the post-processing liquid ejected from the post-processing head 6 lands at the point P can be expressed by the following equation M.

[0159] T2=A+B2+2×(LP+LC) (Formula M)

[0160] As a result, the time ΔT from the time the pre-treatment liquid lands at point P to the time the post-treatment liquid lands can be expressed by the following formula N.

[0161] ΔT=T2-T1=B2-B1+2×(LP+LC) (Formula N)

[0162] In the first operation, the carriage 3 moves from the return area 14 to the maintenance area 13 (movement to the left). The time ΔT from the time the pre-treatment liquid lands at point P to the time the post-treatment liquid lands can be expressed by the following equation (O).

[0163] ΔT=LC-B2-(LC-B1)+2×(LP+LC)=B1-B2+2×(LP+LC) (Formula O)

[0164] Since printing is performed intermittently in the conveying direction F of the workpiece W, portions adjacent to portions printed at different times in the conveying direction F are formed on the workpiece W. Figure 5A 、 Figure 5B It shows that areas A1 and A2 are printed at different times. Moreover, since the main scanning directions S of the printing heads are opposite in areas A1 and A2, the time intervals for the landing of the pre-treatment liquid, ink and post-treatment liquid are also different, so the printing results may differ due to different printing conditions. In addition, the boundary where the main scanning direction S of this printing changes is called the scanning boundary. If the difference between the various times ΔT of the above-mentioned formulas N and O at the scanning boundary is large, the scanning boundary may be significant due to the difference in printing results. For example, the difference in color concentration caused by the influence of the time difference from the landing of the pre-treatment liquid to the landing of the post-treatment liquid may be significant. Therefore, it is preferred that the difference between ΔT of formula N and ΔT of formula O, that is, the absolute value of the time difference Δt (formula P) is small.

[0165] Δt=2×(B1-B2) (Formula P)

[0166] The present inventors have found that in order to normalize the above-mentioned Δt, the absolute value of (B1-B2) / LC is divided by the distance LC×2, and is used as an index. As shown in the following formula 2, the absolute value is preferably less than 1 / 2, and most preferably B1=B2.

[0167] |(B1-B2) / LC|≤1 / 2 (Formula 2)

[0168] By configuring the pre-treatment head 5 and the post-treatment head 6 to satisfy the aforementioned equation 2, the time difference between the landing of the pre-treatment liquid and the landing of the post-treatment liquid at the scanning boundary can be reduced. This also means that the time difference between the landing of the pre-treatment liquid and the landing of the post-treatment liquid can be reduced. As a result, the pre-treatment liquid, ink, and post-treatment liquid can be stably and sequentially landed on the workpiece W, making it less likely that variations in image quality will occur on the workpiece W.

[0169] Furthermore, similar to the case of Formula 1, when at least one of the pre-processing heads 5 and the post-processing heads 6 is arranged in plurality, it is preferred that at least one of the plurality of heads be arranged so as to satisfy Formula 2, and it is more preferred that all of the plurality of heads be arranged so as to satisfy Formula 2. In this case, not only can the time difference between the landing of the pre-processing liquid and the landing of the post-processing liquid at the scanning boundary be reduced, but also, since the processing liquid can be ejected from the other processing heads, the amount of the processing liquid that can be ejected can be increased.

[0170] Furthermore, from the viewpoint of the above-mentioned evaluation at the scan boundary, it can be said that not only the head arrangement defined by the above-mentioned Expression 2 but also the head arrangement defined by the above-mentioned Expression 1 is appropriate.

[0171] <Example 7>

[0172] Figure 14 This is a top view of the carriage 3F showing the head configuration according to Example 7. Based on the above concept, in this head configuration, LC = 10, B1 = 3, B2 = 7, and |(B1 - B2) / LC| is 0.4, satisfying the above equation 2. Furthermore, in this embodiment, the spacing (distance) between adjacent ink heads 4 in the main scanning direction S is 2. The distance between the pre-processing head 5 and the second ink head 4B or the third ink head 4C in the main scanning direction S is 1, and the distance between the post-processing head 6 and the fourth ink head 4D or the fifth ink head 4E in the main scanning direction S is also 1.

[0173] <Example 8>

[0174] Figure 15 This is a top view of the carriage 3G showing the head configuration according to Example 8. In this example, the pre-processing head 5 and the post-processing head 6 correspond to one end head. In this head configuration, LC = 6, B1 = 0, B2 = 0, and |(B1 - B2) / LC| is 0, satisfying the above-mentioned equation 2.

[0175] Hereinafter, preferred head configurations will be further described based on other embodiments.

[0176] <Example 9>

[0177] Figure 161 is a top view schematically showing a carriage 3H having a head configuration according to Example 9. Example 9 differs from Example 1 in that the number of respective unit heads is increased. That is, the ink head 4 is the same as Example 1 in that it includes the first to sixth ink heads 4A to 4F that eject six different colors of ink, respectively. However, each of the ink heads 4A to 4F of each color has three (a total of 18) unit heads. In other words, the ink head 4 has three (an odd number of) ink head columns including a first ink head column 41, a second ink head column 42, and a third ink head column 43. The pre-processing head 5 arranged on the upstream side in the conveying direction F of the ink head 4 includes two unit heads, and the post-processing head 6 arranged on the downstream side includes three unit heads. In addition, the points in which the pre-processing head 5 and the post-processing head 6 are respectively arranged within the range of the configuration width of the ink head 4 in the main scanning direction S are the same as in Example 1.

[0178] The first ink head 4A includes an upstream head 4AA, a center head 4AB, and a downstream head 4AC as the unit heads. The upstream head 4AA is positioned at the most upstream side of the first ink head 4A in the conveying direction F of the carriage 3A. The downstream head 4AC is positioned downstream of the upstream head 4AA at the same position as the upstream head 4AA in the main scanning direction S. The center head 4AB is positioned to the right of the upstream head 4AA and the downstream head 4AC in the main scanning direction S, and is positioned downstream of the upstream head 4AA and upstream of the downstream head 4AC in the conveying direction F. The center head 4AB is positioned so as to partially overlap with the upstream head 4AA and the downstream head 4AC in the conveying direction F.

[0179] The second to sixth ink heads 4B to 4F also include upstream heads 4BA, 4CA, 4DA, 4EA, 4FA, center heads 4BB, 4CB, 4DB, 4EB, 4FB, and downstream heads 4BC, 4CC, 4DC, 4EC, and 4FC, similar to the upstream head 4AA, center head 4AB, and downstream head 4AC described above. The upstream heads 4AA to 4FA, center heads 4BB to 4FB, and downstream heads 4BC to 4FC of the first to sixth ink heads 4A to 4F are arranged in a row at predetermined intervals along the main scanning direction S at the same position in the transport direction F, forming a first ink head row 41, a second ink head row 42, and a third ink head row 43.

[0180] The pre-processing heads 5 include a first pre-processing head 5A and a second pre-processing head 5B, arranged in parallel in the main scanning direction S at intervals in the same position in the conveying direction F. The first pre-processing head 5A is arranged so that a portion of its downstream side extends between the upstream head 4EA of the fifth ink head 4E and the upstream head 4FA of the sixth ink head 4F. The second pre-processing head 5B is arranged to the right of the upstream head 4FA and at the same position in the main scanning direction S as the center head 4FB.

[0181] The post-processing heads 6 include a first post-processing head 6A, a second post-processing head 6B, and a third post-processing head 6C, which are arranged at intervals in the main scanning direction S at the same position in the conveying direction F. The first post-processing head 6A is arranged so that a portion of its upstream side extends between the downstream head 4DC of the fourth ink head 4D and the downstream head 4EC of the fifth ink head 4E. The second post-processing head 6B is arranged so that a portion of its upstream side extends between the downstream head 4EC of the fifth ink head 4E and the downstream head 4FC of the sixth ink head 4F. The third post-processing head 6C is arranged to the right of the downstream head 4FC and at the same position in the main scanning direction S as the center head 4FB.

[0182] In Example 9, an odd number of ink head arrays are provided, with LC = 11, B1 = 9, 11, and B2 = 7, 9, and 11. When |(B1-B2) / LC| in Equation 2 is calculated based on these combinations, |(B1-B2) / LC| is distributed as 0, 0.18, and 0.36, satisfying the relationship in Equation 2.

[0183] Furthermore, the head configuration of Example 9 achieves the same advantages as Example 1. Specifically, it achieves both miniaturization of the carriage 3 and the necessary increase in the ejection volume of ink and treatment fluid. In particular, in Example 9, both the pre-processing head 5 and the post-processing head 6 are configured with multiple unit heads, thereby significantly increasing the ejection volume of the pre-processing and post-processing fluids. Since the first to sixth ink heads 4A to 4F also comprise unit heads arranged in three rows, the ink ejection volume can also be significantly increased.

[0184] <Example 10>

[0185] Figure 17 This is a plan view schematically showing a carriage 3I having a head arrangement according to Example 10. Example 10 shows an example in which an ink head 4 that ejects ink and a pre-processing head 5 and a post-processing head 6 that eject a non-colored processing liquid are arranged separately in the main scanning direction.

[0186] The head support frame 31 of the carriage 3I carries first to sixth ink heads 4A to 4F, each ejecting six different colors of ink, a pre-processing head 5, and a post-processing head 6. The first to sixth ink heads 4A to 4F comprise unit heads arranged in three rows, similar to those in Example 9. The pre-processing head 5 includes first and second pre-processing heads 5A and 5B, arranged at the same position in the conveying direction F and spaced apart in the main scanning direction S. The post-processing head 6 includes first to third post-processing heads 6A to 6C, arranged at the same position in the conveying direction F and spaced apart in the main scanning direction S. Their basic structure is the same as that of Example 9.

[0187] In Example 10, the head support frame 31 is divided into an area for arranging the ink heads 4 and an area for arranging the pre-processing heads 5 and the post-processing heads 6. The head support frame 31 is provided with a first area R1 having a larger area and a second area R2 having a smaller area adjacent to the first area R1 in the main scanning direction S. The ink heads 4 (the first to sixth ink heads 4A to 4F) are arranged in the first area R1. On the other hand, the pre-processing heads 5 and the post-processing heads 6 are not arranged in the first area R1, but in the second area R2. In the second area R2, the pre-processing heads 5 are arranged upstream in the conveying direction F of the array of the ink heads 4, and the post-processing heads 6 are arranged downstream.

[0188] In the head configuration of Example 10, which has an odd number of ink head arrays, LC = 14, B1 = 12, 13, and B2 = 12, 13, and 14. When |(B1-B2) / LC| in Equation 2 is calculated based on these combinations, |(B1-B2) / LC| is distributed as 0, 0.07, and 0.14, indicating that the relationship in Equation 2 is satisfied.

[0189] Furthermore, if ink comes into contact with the pre-treatment liquid or post-treatment liquid, ink components may aggregate. If this aggregate adheres to the ink ejection nozzles of the ink head 4, poor ejection may occur. Furthermore, there is a risk that the ink may come into contact with the treatment liquid and aggregate in the recovery system for waste liquid generated during head cleaning and purging, potentially clogging the recovery path. With the carriage 3I of Example 10, since the treatment heads 5 and 6 and the ink head 4 are separated in the main scanning direction S, contact between the ink and the pre-treatment liquid or post-treatment liquid is minimized. Consequently, problems caused by ink aggregation are minimized.

[0190] <Example 11>

[0191] Figure 18 1 is a top view schematically showing a carriage 3J having a head arrangement according to Example 11. In the above-mentioned Examples 8 to 10, the pre-processing head 5 and the post-processing head 6 are arranged near the end (near the right end) of the arrangement width H of the ink head 4 in the main scanning direction S. In Example 11, as in Example 1 ( Figure 6 ) Similarly, an example is shown in which the pre-processing head 5 and the post-processing head 6 are arranged in the central area HC of the arrangement width H. However, as will be described later, Example 11 differs from Example 1 in the arrangement of the ink head 4.

[0192] Mounted on the head support frame 31 of the carriage 3J are the first to sixth ink heads 4A to 4F, each ejecting six different colors of ink, a pre-processing head 5, and a post-processing head 6. The first to sixth ink heads 4A to 4F are comprised of unit heads arranged in two rows, similar to those in Example 1. However, in the first ink head 4A, the downstream head 4A2 is positioned to the right of the upstream head 4A1, and the offset direction of the downstream heads of each ink head 4A to 4F is opposite to that in Example 1. There is one pre-processing head 5, and two post-processing heads 6, namely, a first and a second post-processing head 6A and 6B.

[0193] The pre-processing head 5 and the post-processing head 6 are arranged in the center area HC of the arrangement width H of the first to sixth ink heads 4A to 4F in the main scanning direction S. Similar to the first embodiment described above, the pre-processing head 5 is arranged upstream in the transport direction F, and the post-processing head 6 is arranged downstream of the arrangement of the first to sixth ink heads 4A to 4F. The pre-processing head 5 is arranged at the same position in the main scanning direction S as the downstream head 4C2 of the third ink head 4C, but upstream in the transport direction F. The pre-processing head 5 is arranged so that a portion of its downstream side extends between the upstream heads 4C1 and 4D1 of the third and fourth ink heads 4C and 4D.

[0194] The first and second post-processing heads 6A and 6B are arranged at the same position in the transport direction F, with a predetermined interval in the main scanning direction S. The first post-processing head 6A is positioned so that its upstream portion extends between the downstream head 4B2 of the second ink head 4B and the downstream head 4C2 of the third ink head 4C. The second post-processing head 6B is positioned so that its upstream portion extends between the downstream head 4C2 and the downstream head 4D2 of the fourth ink head 4D.

[0195] In the head configuration of Example 11 having such an even number of ink head rows, LC = 11, B1 = 5, and B2 = 4 and 6. When (B1 + B2) / LC in Formula 1 is calculated based on these combinations, (B1 + B2) / LC is 0.8 and 1, which shows that the relationship in Formula 1 is satisfied.

[0196] Furthermore, the pre-processing heads 5 and the post-processing heads 6 are not only arranged in the central area HC of the arrangement width H, but are also arranged so that the arrangement center of the pre-processing head 5 and the arrangement centers of the first and second post-processing heads 6A and 6B coincide with each other in the main scanning direction S. In this embodiment, since there is only one pre-processing head 5, the center of the pre-processing head 5 in the main scanning direction S serves as the arrangement center C1. For the post-processing heads 6, the midpoint between the first post-processing head 6A and the second post-processing head 6B serves as the arrangement center C2. The pre-processing heads 5 and the post-processing heads 6 are arranged on the head support frame 31 so that their arrangement centers C1 and arrangement centers C2 are located at the same position in the main scanning direction S.

[0197] If based on Figure 4 As described, in this embodiment, the carriage 3 repeatedly performs forward main scanning and return main scanning, causing the pre-treatment liquid, ink, and post-treatment liquid to sequentially land on the workpiece W. By employing the head arrangement of Example 11 while employing such bidirectional main scanning, it is possible to reduce the difference in time from the landing of the pre-treatment liquid on the workpiece W to the landing of the ink, and the difference in time from the landing of the ink to the landing of the post-treatment liquid, at each main scanning position.

[0198] In this case, the central region HC is preferably located in the center of the arrangement width H and has a width of half, and more preferably one-third, of the arrangement width H. Arranging the processing heads in the central region HC means that the arrangement centers of the processing heads are arranged in the central region HC, and more than half of the arrangement centers of the processing heads are arranged in the central region HC. Alternatively, all arrangement centers of the processing heads may be arranged in the central region HC.

[0199] <Example 12>

[0200] Figure 19 This is a plan view schematically showing a carriage 3K having a head arrangement according to Example 12. Example 12 shows an example in which the pre-processing head 5 and the post-processing head 6 are separately arranged at one end and the other end of the head support frame 31 in the main scanning direction S with the ink head 4 interposed therebetween.

[0201] The head support frame 31 is equipped with the same Figure 18 ) The first to sixth ink heads 4A to 4F, the pre-processing head 5, and the post-processing head 6 are arranged identically. The pre-processing head 5 includes one head, and the post-processing head 6 includes two heads, a first post-processing head 6A and a second post-processing head 6B. The pre-processing head 5 is arranged on the other end side (right side) in the main scanning direction S and upstream side in the conveying direction F relative to the ink head 4. The first and second post-processing heads 6A and 6B are arranged on one end side (left side) in the main scanning direction S and downstream side in the conveying direction F relative to the ink head 4. The first and second post-processing heads 6A and 6B are arranged at the same position in the conveying direction F in the main scanning direction S with a gap therebetween.

[0202] In the head configuration of Example 12 having such an even number of ink head rows, LC = 14, B1 = 14, and B2 = 0 and 1. When (B1 + B2) / LC in Formula 1 is calculated based on these combinations, (B1 + B2) / LC is 1 and 1.07, which shows that the relationship in Formula 1 is satisfied.

[0203] Furthermore, similar to Example 10, the head arrangement of Example 12 also divides the head support frame 31 into two areas: the ink head 4 and the pre-processing head 5 and post-processing head 6. Specifically, the right end of the head support frame 31 is designated as the area for the pre-processing head 5, the left end as the area for the post-processing head 6, and the remaining central area as the area for the ink head 4. This head arrangement of Example 12 also minimizes contact between the ink and the pre-processing liquid or post-processing liquid.

[0204] <Example 13>

[0205] Figure 20 This is a plan view schematically showing a carriage 3L having a head arrangement according to Example 13. In Example 13, the first to sixth ink heads 4A to 4F, which eject six different colors of ink, are arranged in a row in the main scanning direction S (a first ink head row 41).

[0206] The head support frame 31 of the carriage 3L carries the first to sixth ink heads 4A to 4F, each having two unit heads, a pre-processing head 5, and a post-processing head 6. The pre-processing head 5 comprises one head, and the post-processing head 6 comprises two heads, a first head 6A and a second head 6B. This embodiment differs from the first embodiment described above and other embodiments in that the first to sixth ink heads 4A to 4F, each having two unit heads, are arranged along the main scanning direction S at the same position in the conveyance direction F. The pre-processing head 5 and the post-processing head 6 are respectively arranged upstream and below the right side of the arrangement of the first to sixth ink heads 4A to 4F.

[0207] In the head configuration of Example 13 having such a single ink head array, LC = 13, B1 = 12, and B2 = 12 and 13. When |(B1-B2) / LC| in Formula 2 is calculated based on these combinations, |(B1-B2) / LC| is 0 and 0.08, respectively, satisfying the relationship in Formula 2.

[0208] Furthermore, the head configuration of Example 13 is suitable for situations where the width in the main scanning direction S can be relatively large, but the width in the transport direction F should be shortened. Furthermore, the necessary ejection volumes of ink and treatment fluid can be increased. Furthermore, because the placement area for the ink head 4 is separated from the placement areas for the pre-processing head 5 and the post-processing head 6 by the head support frame 31, contact between the ink and the pre-processing fluid or post-processing fluid can be minimized.

[0209] <Example 14>

[0210] In Example 14 and the following Example 15, head configurations are illustrated that take measures to prevent the heating of the processing heads 5 and 6. Generally, heads that eject liquid by jetting generate heat because they use electricity to pressurize the liquid. The ink head 4 only ejects when forming the desired color dots. In contrast, the pre-processing head 5 and the post-processing head 6 need to eject the pre-processing liquid and the post-processing liquid corresponding to dots of all colors. Therefore, the pre-processing head 5 and the post-processing head 6 are more likely to heat up than the ink heads 4. Therefore, it is preferable to configure the head configuration in such a way that the pre-processing head 5 and the post-processing head 6 will heat up.

[0211] Figure 21 14. The rear frame 32 (engaging portion) of the carriage 3M is supported in a cantilevered state by the guide rail 17 (holding member) ( Figure 1 ) is held. The ink head 4 having the first to sixth ink heads 4A to 4F, a pre-processing head 5, and a post-processing head 6 having the first and second post-processing heads 6A and 6B are mounted on the head support frame 31. These heads are arranged in the same manner as Figure 6 The embodiment 1 shown is the same, so the description is omitted here.

[0212] In the head configuration of Example 14, LC = 11, B1 = 6, and B2 = 5, 7. When (B1 + B2) / LC of Formula 1 is calculated based on these combinations, (B1 + B2) / LC is 1, 1.18, which satisfies the relationship of Formula 1.

[0213] In addition, in this embodiment, the pre-processing head 5 is composed of one unit head, and the post-processing head 6 is composed of two unit heads (first and second post-processing heads 6A and 6B). The pre-processing head 5 with fewer unit heads among these pre-processing heads 5 and post-processing heads 6 is arranged on the base end side 311 of the head support frame 31. The post-processing head 6 with more unit heads is arranged on the distal end side 312. In other words, the upstream end edge of the head support frame 31 in the conveying direction F is the side held by the guide rail 17.

[0214] As described above, the processing heads 5 and 6 generate heat due to the ejection operation. Figure 21 As schematically shown in the figure, the heated pre-processing head 5 releases heat ha. The same applies to the first and second post-processing heads 6A and 6B. This heat ha heats the head support frame 31 of the carriage 3M, potentially causing thermal deformation of the head support frame 31, its retaining structure, the rear frame 32, and the mounting brackets between the rear frame 32 and the timing belt 16. This thermal deformation can affect the landing accuracy of ink ejected from the ink head 4 in the cantilevered carriage 3M.

[0215] However, in the carriage 3M of Example 14, the pre-processing head 5, which has a smaller number of unit heads, is positioned on the cantilevered side of the head support frame 31, i.e., the base end 311. This reduces the effects of thermal deformation (reduced landing accuracy). If the post-processing head 6, which has a larger number of unit heads, is positioned on the base end 311, the rear frame 32 is exposed to the heat released by the two unit heads, causing it to heat up even more and become more susceptible to thermal deformation.

[0216] Furthermore, in the carriage 3M of Example 14, the pre-processing head 5 is positioned in a position other than the ends of the head array HA (head arrangement area) of the ink head 4 and the processing heads 5 and 6 in the main scanning direction S. Of the heads 4, 5, and 6 mounted on the carriage 3M, the pre-processing head 5 is positioned closest to the rear frame 32 (engaging portion). The pre-processing head 5 is positioned other than the end of the head array HA, i.e., the arrangement end 313.

[0217] Since the carriage 3M cannot be unnecessarily increased in size, if a head is arranged at the configuration end 313 of the head array body in the main scanning direction S, the head becomes the head closest to the corner of the carriage 3M (head support frame 31) in the main scanning direction S. Since the vicinity of the configuration end 313 is also near the cantilever-supported rear frame 32, if thermal deformation occurs in this vicinity, it is possible to cause deformation or positional displacement of the head support frame 31 in the height direction or horizontal direction. This reduces the landing position accuracy of the heads 4, 5, and 6 mounted on the carriage 3M. Therefore, by not arranging the high-temperature pre-processing head 5 and post-processing head 6 in the area of the configuration end 313, the above-mentioned thermal deformation problem can be made less likely to occur.

[0218] In this embodiment, the row of ink heads 4 arranged on the engaging portion side is arranged in two rows (the first ink head row 41 and the second ink head row 42). Figure 21 The zigzag arrangement is arranged in a position offset to the right. Furthermore, the pre-processing head 5, which has a smaller number of processing heads, is arranged on the engaging portion side, and the pre-processing head 5 is arranged in the center of the zigzag arrangement. This arrangement allows the heads to be arranged in a manner such that the processing heads are not arranged at the arrangement end 313.

[0219] Reference Figure 21The head configuration of the carriage 3M shown in the figure further illustrates a preferred ink head configuration example. In the carriage 3M, the high-temperature pre-processing head 5 is configured so that a portion of it is adjacent to the ink head 4. Specifically, the pre-processing head 5 is adjacent to the upstream heads 4C1 and 4D1 of the third and fourth ink heads 4C and 4D in the main scanning direction S, and is adjacent to the downstream head 4D2 of the fourth ink head 4D in the conveying direction F. In addition, the first post-processing head 6A is adjacent to the downstream heads 4C2 and 4D2 of the third and fourth ink heads 4C and 4D in the main scanning direction S, and is adjacent to the upstream head 4C1 in the conveying direction F. The second post-processing head 6B is adjacent to the downstream heads 4D2 and 4E2 of the fourth and fifth ink heads 4D and 4E in the main scanning direction S, and is adjacent to the upstream head 4D1 in the conveying direction F. On the other hand, the pre-processing head 5 and the post-processing head 6 are not adjacent to the first, second, and sixth ink heads 4A, 4B, and 4F.

[0220] In the above-described head arrangement, for example, the third, fourth, and fifth ink heads 4C, 4D, and 4E (first ink heads that eject first color ink) that eject yellow, red, and blue ink, respectively, have a greater number of unit heads (total number of heads) adjacent to the pre-processing head 5 and the post-processing head 6 than the first, second, and sixth ink heads 4A, 4B, and 4F (second ink heads that eject second color ink), that eject orange, green, and black ink, respectively. In other words, the third, fourth, and fifth ink heads 4C, 4D, and 4E are more susceptible to high temperatures than the other ink heads 4A, 4B, and 4F.

[0221] If the viscosity of the ink changes significantly with temperature, the ink ejection characteristics (e.g., ejection volume) from the ink head will also change. The viscosity change characteristics due to temperature vary depending on the type of ink. Therefore, in the present embodiment, inks ejected from the third, fourth, and fifth ink heads 4C, 4D, and 4E, which are susceptible to high temperatures, are selected to have a viscosity that changes less with temperature than the ink ejected from the first, second, and sixth ink heads 4A, 4B, and 4F. Consequently, even if the third, fourth, and fifth ink heads 4C, 4D, and 4E are heated by the pre-processing head 5 and the post-processing head 6, changes in the ejection volume and ejection velocity of the ink ejected from these ink heads 4C, 4D, and 4E due to temperature can be reduced.

[0222] At this time, for each ink, the unit number of processing heads adjacent to the ink head 4 can also be used to evaluate the maximum number of unit numbers of processing heads adjacent to the ink head 4 ejecting a certain ink. For the first, second, and sixth ink heads 4A, 4B, and 4F, the maximum number of unit numbers of processing heads adjacent to each other is 0. For the third ink head 4C, the maximum number of unit numbers of processing heads adjacent to each other is 2. For the fourth ink head 4D, the maximum number of unit numbers of processing heads adjacent to each other is 3. For the fifth ink head 4E, the maximum number of unit numbers of processing heads adjacent to each other is 1.

[0223] Furthermore, for each ink, the unit number of processing heads adjacent to the ink head 4 can also be evaluated as the average of the unit number of adjacent processing heads among the ink heads 4 ejecting a particular ink. For the first, second, and sixth ink heads 4A, 4B, and 4F, the average unit number of adjacent processing heads is 0. For the third ink head 4C, the average unit number of adjacent processing heads is 1.5. For the fourth ink head 4D, the average unit number of adjacent processing heads is 2.5. For the fifth ink head 4E, the average unit number of adjacent processing heads is 0.5.

[0224] As a combined evaluation of these, for example, the maximum number of unit heads of adjacent processing heads may be evaluated first, and for inks having no difference in the evaluation, the average number of unit heads of adjacent processing heads may be evaluated.

[0225] Alternatively, the order in which the ink head 4 ejecting each ink is likely to heat up may be evaluated, and the inks having the smallest viscosity change with temperature may be ejected in the order in which the temperature is likely to heat up.

[0226] <Example 15>

[0227] Example 15 shows an embodiment that considers countermeasures for high temperatures of the pre-processing head 5 and post-processing head 6 among multiple ink heads that eject the same color ink. In the above embodiments, the first to sixth ink heads 4A to 4F of each color are each provided with two or three unit heads. If there is a significant difference in the number of unit heads adjacent to the pre-processing head 5 or post-processing head 6 among these unit heads, the ink ejection characteristics of the unit heads may differ significantly. This embodiment shows an example of a head configuration that reduces this difference in the number of adjacent unit heads.

[0228] Figure 22 This is a top view schematically showing a carriage 3N having a head arrangement according to Example 15. The carriage 3N has a head arrangement such that, when the number of two unit heads (same-color ink heads) included in each of the first to sixth ink heads 4A to 4F adjacent to the pre-processing head 5 or the post-processing head 6 in the main scanning direction S and the transport direction F is counted, the difference between the maximum and minimum count values is 1 or less.

[0229] The arrangement of the ink head 4 in the head arrangement of the carriage 3N is the same as that of the above-mentioned Figure 21 The carriage 3M shown has the same head configuration. Meanwhile, the pre-processing head 5 includes first and second pre-processing heads 5A and 5B arranged side by side in the main scanning direction S, with the upstream head 4C1 of the third ink head 4C sandwiched therebetween. The post-processing head 6 includes first and second post-processing heads 6A and 6B arranged side by side in the main scanning direction S, with the downstream head 4C2 sandwiched therebetween.

[0230] In the second ink head 4B of the carriage 3N, the count values of the processing heads 5 and 6 adjacent to the upstream head 4B1 and the downstream head 4B2 in the main scanning direction S and the conveying direction F are 2 and 1, respectively, with a difference of "1." In the third ink head 4C, the count values of the upstream head 4C1 and the downstream head 4C2 are both 3, with a difference of "0." In the fourth ink head 4D, the count value of the upstream head 4D1 is 1, and the count value of the downstream head 4D2 is 2, with a difference of 1. The count values of the remaining ink heads 4A, 4E, and 4F are all "0." Therefore, for all of the first to sixth ink heads 4A to 4F, the difference between the maximum and minimum values is 1 or less, satisfying the above requirements.

[0231] As described above, in Example 15, the difference between the maximum and minimum count values of the upstream heads 4A1 to 4F1 and the downstream heads 4A2 to 4F2 of the first to sixth ink heads 4A to 4F adjacent to the processing heads 5 and 6, respectively, is 1 or less. This prevents significant variations in ink ejection volume between multiple ink heads of the same color.

[0232] <Example 16>

[0233] Figure 23 This is a top view schematically showing a carriage 3P having a head arrangement according to Example 16. Example 16 shows an example in which the pre-processing heads 5 and post-processing heads 6 are arranged as close together as possible on the head support frame 31, rather than being dispersed, thereby reducing contact between the pre-processing liquid and the post-processing liquid and the ink.

[0234] In Example 16, a head arrangement satisfying the following requirements (A) to (C) is exemplified.

[0235] (A) When the number of unit heads of the pre-processing head 5 and the post-processing head 6 is greater, and the number of unit heads of the post-processing head 6 is less, and the condition m=n+odd number is satisfied,

[0236] (B) the arrangement or arrangement center of the one or more pre-processing heads 5 in the main scanning direction S coincides with the arrangement or arrangement center of the one or more post-processing heads 6 in the main scanning direction S, and

[0237] (C) The arrangement or arrangement center of the pre-processing head 5 and the post-processing head 6 coincides with the arrangement position of one of the ink heads 4 in the main scanning direction S.

[0238] Figure 23 The carriage 3P shown includes an ink head 4, a pre-processing head 5, and a post-processing head 6 having a first and a second post-processing head 6A, 6B. Figure 21The same as others. Therefore, the head configuration in Example 16 also satisfies the relationship of the above-mentioned formula 1. In the case of this example, there are m=2 post-processing heads 6 and n=1 pre-processing head 5. Therefore, m=n+odd number, which satisfies the above-mentioned requirement (A). In addition, the configuration center of the pre-processing head 5 and the arrangement center of the post-processing head 6 are both the center C in the figure, which also satisfies the above-mentioned requirement (B). Moreover, the center C is consistent with the configuration position of the downstream head 4D2 of the fourth ink head 4D, which also satisfies the above-mentioned requirement (C).

[0239] According to the head arrangement of Example 16, the pre-processing head 5 and the post-processing head 6 can be mounted on the carriage 3P in a somewhat concentrated state. This reduces the number of ink heads 4A to 4F located near the pre-processing head 5 or the post-processing head 6. Consequently, the likelihood of pre-processing liquid and post-processing liquid coming into contact with ink on the carriage can be reduced.

[0240] <Example 17>

[0241] In Example 17, a preferred arrangement relationship between the heads 4, 5, and 6 on the carriage and the sub-tanks that supply ink or processing liquid thereto is exemplified. Figure 24 This is a top view showing a carriage 3Q and a sub-tank arrangement having a head arrangement according to Example 17. The carriage 3Q includes an ink head 4 having first to sixth ink heads 4A to 4F, a pre-processing head 5, and a post-processing head 6 having first and second post-processing heads 6A and 6B. Figure 21 Therefore, the head configuration in Example 17 satisfies the relationship of the above-mentioned formula 1.

[0242] The carriage 3Q also carries auxiliary tanks 7. The auxiliary tanks 7 include ink auxiliary tanks 7A to 7F, a pre-treatment liquid auxiliary tank 71, and a post-treatment liquid auxiliary tank 72 (each of which is a treatment liquid auxiliary tank). Ink, pre-treatment liquid, and post-treatment liquid are supplied to these auxiliary tanks 7 from a main tank (not shown). The ink auxiliary tanks 7A to 7F supply the ink to the first to sixth ink heads 4A to 4F, respectively. For example, ink of the first color is supplied from the first tank 7A1 of the ink auxiliary tank 7A via the pipe P1 to the upstream head 4A1 of the first ink head 4A, and from the second tank 7A2 via the pipe P1 to the downstream head 4A2. The second to sixth ink heads 4B to 4F are similarly supplied with ink of the second to sixth colors, respectively.

[0243] The arrangement order of the ink sub-tanks 7 in the main scanning direction S is the same as the arrangement order of the ink heads 4 supplied with ink by each ink sub-tank 7 in the main scanning direction S. Alternatively, ink may be supplied from a single ink sub-tank 7 to multiple ink heads 4 that eject ink of the same color. In this case, the ink heads 4 sharing the ink sub-tank 7 may be arranged in a concentrated position in the main scanning direction S. Furthermore, it is preferable to arrange the ink heads 4 ejecting the same ink in a concentrated position in the main scanning direction S. In the main scanning direction S, the arrangement order of the ink sub-tanks 7 for each color may be the same as the arrangement order of the ink heads 4 for each color.

[0244] The pre-treatment liquid sub-tank 71 supplies the pre-treatment liquid to the pre-treatment head 5 via the pipe P2. The post-treatment liquid sub-tank 72 includes a first tank 72A and a second tank 72B. The first and second tanks 72A and 72B supply the post-treatment liquid to the first and second post-treatment heads 6A and 6B, respectively, via the pipe P3.

[0245] The ink sub-tanks 7A to 7F are mounted on the carriage 3Q so as to be aligned along the main scanning direction S. The treatment liquid sub-tanks 71 and 72 are arranged along the main scanning direction S at positions different from those of the ink sub-tanks 7A to 7F in the conveyance direction F. Specifically, the first and second tanks 72A and 72B of the pre-treatment liquid sub-tank 71 and the post-treatment liquid sub-tank 72 are arranged in a row along the main scanning direction S, downstream of the ink sub-tanks 7A to 7F in the conveyance direction F. Alternatively, only the pre-treatment liquid sub-tank 71 may be arranged upstream of the ink sub-tanks 7A to 7F.

[0246] The liquid in the sub-tank 7, carried on the carriage 3Q, which reciprocates in the main scanning direction S, is subjected to acceleration in the main scanning direction S. The sub-tank 7 is connected to the heads 4, 5, and 6 via pipes P1, P2, and P3. However, if the sub-tanks 7 are widely distributed on the carriage 3Q, the arrangement range of the pipes P1 to P3 in the main scanning direction S also increases. Because these pipes P1 to P3 are also filled with ink or processing liquid, the acceleration may cause meniscus breakdown in the ejection area of the heads 4, 5, and 6.

[0247] However, according to the configuration of Example 17, the ink sub-tanks 7A to 7F, like the first to sixth ink heads 4A to 4F, are mounted on the carriage 3Q in an arrangement aligned along the main scanning direction S. Therefore, the ink sub-tanks 7A to 7F can be positioned within a relatively narrow area on the head support frame 31 of the carriage 3Q. Similarly, the pre-treatment liquid sub-tank 71 and the post-treatment liquid sub-tank 72 can also be positioned within a relatively narrow area on the head support frame 31 of the carriage 3Q.

[0248] Furthermore, since the pre-treatment liquid sub-tank 71 and the post-treatment liquid sub-tank 72 are positioned differently from the ink sub-tanks 7A to 7F in the transport direction F, the positions of the pre-treatment liquid sub-tank 71 and the post-treatment liquid sub-tank 72 and the treatment heads to which they supply treatment liquid can be arranged so that the positional difference in the main scanning direction S between the pre-treatment liquid sub-tank 71 and the post-treatment liquid sub-tank 72 is minimal. Consequently, the distribution range of the pre-treatment liquid in the interconnected pre-treatment liquid sub-tank 71, the pipeline P, and the pre-treatment head 5 in the main scanning direction S can be reduced, making them less susceptible to the effects of the aforementioned acceleration. Similarly, the distribution range of the interconnected post-treatment liquid in the main scanning direction S can be reduced, making them less susceptible to the effects of the aforementioned acceleration.

[0249] Similarly, the positional differences between the ink sub-tanks 7A to 7F and the ink heads 4 to which they are supplied in the main scanning direction S can be minimized. This reduces the distribution range of the ink in the main scanning direction S, making it less susceptible to the acceleration.

[0250] <About the Conveying Pitch of Workpiece W>

[0251] In the above-mentioned embodiments, the case where the workpiece W is printed while being intermittently conveyed at a head pitch (the spacing between adjacent heads in the conveying direction F) is described, but the present invention is not limited to this. Figure 25A 、 Figure 25B Schematic diagrams for explaining the case of conveying the workpiece W at different conveyance pitches. In the following description, it is assumed that each processing liquid and ink is printed on the workpiece W in all main scans when printing on the workpiece W at maximum density.

[0252] Reference Figure 25A In the case of an even number of ink head arrays (the first ink head array 41 and the second ink head array 42) and the conveying pitch of the workpiece W is set to 1 / 2 head pitch (a pitch of 1 / 2 of the interval between adjacent heads in the conveying direction F), it can be regarded as the same as Figure 25B The same is true for the case of one head spacing in the head configuration shown. Figure 25B In the figure, the ink head 4 includes a first ink head row 41, a second ink head row 42, a third ink head row 43, and a fourth ink head row 44. The pre-processing head 5 includes a pre-processing head 5A and a second pre-processing head 5B. The post-processing head 6 includes a first post-processing head 6A and a second post-processing head 6B. The intervals between the heads in the transport direction F are the same.

[0253] In addition, if Figure 25B As shown, at least one of the pre-processing head 5 and the post-processing head 6 (in Figure 25BIn the case of multiple processing heads in the conveying direction F, the time interval from the last landing of the pre-treatment liquid to the first landing of the post-treatment liquid can be evaluated by formula 1 and formula 2. Figure 25B In the example, since the effective values of B1 and B2 are the same as when the ink heads are arranged in four rows, it is sufficient to satisfy the above formula 1. As described above, even when printing is performed with a 1 / n head pitch (a pitch that is 1 / n of the spacing between adjacent heads in the transport direction F, where n is a natural number), the evaluation using formula 1 or formula 2 can be performed in the same manner.

[0254] Furthermore, considering the case where the ink head 4 has an odd number of ink head rows and the workpiece W is transported at a transport pitch = 1 / n head pitch, when the transport pitch n is an odd number, it can be considered the same as the case where the number of ink head rows is an odd number, and thus Formula 2 can be applied. On the other hand, when the transport pitch n is an even number, Formula 1 can be applied in the same manner as the case where the number of ink head rows is an even number.

[0255] As described above, even when the conveying spacing of the workpiece W is a spacing other than one head spacing, the difference in time from the landing of the pre-processing liquid to the landing of the post-processing liquid can be reduced by configuring the pre-processing head 5 and the post-processing head 6 to satisfy Formulas 1 and 2 as described above.

[0256] According to the above description, in the following cases I and II, the scanning direction of the slide 3 when the pre-processing head 5 sprays the pre-processing liquid (the last scan when the pre-processing head that is ejected is performed multiple times) is opposite to the scanning direction of the slide 3 when the post-processing head 6 sprays the post-processing liquid (the first scan when the post-processing head that is ejected is performed multiple times).

[0257] I: A case where the number of ink head rows of the ink head 4 in the conveying direction F is an even number (in this case, the conveying pitch of the workpiece W may be 1 head pitch or 1 / n head pitch).

[0258] II: A case where the number of ink head rows of the ink head 4 in the transport direction F is an odd number and the transport pitch of the workpiece W is 1 / n head pitch (n is an even number).

[0259] In this case, the pre-processing head 5 and the post-processing head 6 may be arranged so as to satisfy Expression 1.

[0260] In addition, in the following case III, the scanning direction of the slide 3 when the pre-processing head 5 sprays the pre-processing liquid (the last scan when the pre-processing head that is ejected is scanned multiple times) is the same as the scanning direction of the slide 3 when the post-processing head 6 sprays the post-processing liquid (the first scan when the post-processing head that is ejected is scanned multiple times).

[0261] III: A case where the number of ink head rows of the ink head 4 in the conveying direction F is an odd number and the conveying pitch of the workpiece W is one head pitch or 1 / n head pitch (n is an odd number).

[0262] In this case, the pre-processing head 5 and the post-processing head 6 may be arranged so as to satisfy the formula (2).

[0263] <About Inkjet Recording Method>

[0264] As described above, the inkjet printer 1 described in each embodiment includes a single ink head array mounted on the carriage 3 at a predetermined position in the transport direction F, or multiple ink head arrays mounted on the carriage 3 aligned in the transport direction F, a pre-processing head, and a post-processing head. Each of the one or more ink head arrays includes multiple ink heads arranged in the main scanning direction S and each ejects ink for image formation. The pre-processing head 5 is positioned upstream of the one or more ink head arrays in the transport direction F and ejects a non-colored pre-processing liquid. The post-processing head 6 is positioned downstream of the one or more ink head arrays in the transport direction F and ejects a non-colored post-processing liquid.

[0265] Furthermore, an inkjet recording method in the above-mentioned inkjet printer 1 includes: arranging the pre-processing head 5 so as to satisfy the relationship 1 / 2≤(B1+B2) / LC≤3 / 2 (Formula 1) when, among the plurality of ink heads 4, the pre-processing head 5, and the post-processing head 6, the head arranged closest to one end side in the main scanning direction S is referred to as the one end side head, the head arranged closest to the other end side is referred to as the other end side head, the distance from the one end side head to the other end side head in the main scanning direction S is referred to as LC, the distance from the one end side head to the pre-processing head 5 in the main scanning direction S is referred to as B1, and the distance from the one end side head to the post-processing head 6 in the main scanning direction S is referred to as B2. and a post-processing head 6; while moving the slide 3 along a first direction (for example, the left direction) on the main scanning direction S, the pre-processing liquid is sprayed from the pre-processing head 5 to a specified recording area on the workpiece W; while conveying the workpiece W along the conveying direction F at a specified conveying spacing and moving the slide 3 along the main scanning direction S, the ink head 4 is sprayed to the recording area to which the pre-processing liquid has been sprayed; while further conveying the workpiece W along the conveying direction F at the conveying spacing and moving the slide 3 along a second direction (for example, the right direction) opposite to the first direction on the main scanning direction S, the post-processing liquid is sprayed from the post-processing head 6 to the recording area to which the ink has been sprayed.

[0266] According to this method, an all-in-one inkjet printer 1, which includes three heads for dispensing a pre-treatment liquid, ink, and post-treatment liquid, mounted on a single carriage 3, can efficiently form an image on a workpiece W. Furthermore, because the pre-treatment head 5, ink head 4, and post-treatment head 6 are sequentially arranged in the conveying direction F, the pre-treatment liquid, ink, and post-treatment liquid can be dispensed in a desired landing order. Furthermore, by appropriately arranging the pre-treatment head 5 and post-treatment head 6 to satisfy Equation 1, the time difference between the landing of the pre-treatment liquid and the landing of the post-treatment liquid can be reduced. As a result, variations in image quality on the workpiece W are less likely to occur.

[0267] In particular, according to the above method, when the number of ink head columns of the ink head 4 in the conveying direction is an even number or when the number of ink head columns of the ink head 4 in the conveying direction F is an odd number and the conveying spacing of the workpiece W is 1 / n head spacing (n is an even number), the time difference from the landing of the pre-treatment liquid to the landing of the post-treatment liquid can be reduced.

[0268] In addition, another inkjet recording method in the above-mentioned inkjet printer 1 includes: configuring the pre-processing head 5 and the post-processing head 6 in a manner that satisfies the relationship |(B1-B2) / LC|≤1 / 2 (Formula 2); while moving the slide 3 along the first direction (for example, the left direction) in the main scanning direction S, the pre-processing liquid is ejected from the pre-processing head 5 to the specified recording area on the workpiece W; while conveying the workpiece W along the conveying direction F at a specified conveying spacing and moving the slide 3 along the main scanning direction S, the ink is ejected from the ink head 4 to the recording area to which the pre-processing liquid has been ejected; while further conveying the workpiece W along the conveying direction F at the conveying spacing and moving the slide 3 along the first direction on the main scanning direction S, the post-processing liquid is ejected from the post-processing head 6 to the recording area to which the ink has been ejected.

[0269] In this method, it is also possible to utilize a multifunctional, all-in-one inkjet printer 1 in which three heads for dispensing the pre-treatment liquid, ink, and post-treatment liquid are mounted on a single carriage to effectively form an image on the workpiece W. Furthermore, because the pre-treatment head 5, ink head 4, and post-treatment head 6 are sequentially arranged in the conveying direction, the pre-treatment liquid, ink, and post-treatment liquid can be dispensed in the desired landing order. Furthermore, by appropriately arranging the pre-treatment head 5 and post-treatment head 6 to satisfy Equation 2, the time difference between the landing of the pre-treatment liquid and the landing of the post-treatment liquid can be reduced. As a result, it is difficult for differences in image quality to occur on the workpiece W.

[0270] In particular, according to the above method, when the number of ink head columns of the ink head 4 in the conveying direction F is an odd number and the conveying spacing of the workpiece W is one head spacing or 1 / n head spacing (n is an odd number), the time difference from the landing of the pre-treatment liquid to the landing of the post-treatment liquid can be reduced.

[0271] <About Comparative Example>

[0272] Figure 26 This is a top view of the carriage 3Z1 showing the head configuration according to Comparative Example 1, which is compared with the present invention. In the head configuration of Comparative Example 1, which has an even number of ink head rows, LC = 11, B1 = 0, and B2 = 5. When (B1 + B2) / LC in Equation 1 is calculated based on these combinations, (B1 + B2) / LC is 0.45, indicating that the relationship in Equation 1 is not satisfied.

[0273] same, Figure 27 This is a top view of carriage 3Z2 showing the head configuration according to Comparative Example 2, which is compared with the present invention. In the head configuration of Comparative Example 2, which has an odd number of ink head rows, LC = 7, B1 = 0, and B2 = 7. When |(B1 - B2) / LC| in Equation 2 is calculated based on these combinations, |(B1 - B2) / LC| is 1, indicating that the relationship in Equation 2 is not satisfied.

[0274] like Figure 26 and Figure 27 In the case of the head arrangement shown, the time from the landing of the pre-processing liquid to the landing of the post-processing liquid varies depending on the image position in the main scanning direction, resulting in a tendency for the image quality on the workpiece W to vary.

[0275] [Summary of the Invention]

[0276] An inkjet recording device according to one aspect of the present invention includes a conveying unit, a carriage, a plurality of ink head arrays, a pre-processing head, and a post-processing head. The conveying unit conveys the recording medium along a predetermined conveying direction. The carriage reciprocates along a main scanning direction intersecting the conveying direction. The plurality of ink head arrays are mounted on the carriage in a manner arranged along the conveying direction, and the plurality of ink head arrays are an even number of ink head arrays. The pre-processing head is arranged on the upstream side relative to the plurality of ink head arrays in the conveying direction, and ejects a non-colored pre-processing liquid. The post-processing head is arranged on the downstream side relative to the plurality of ink head arrays in the conveying direction, and ejects a non-colored post-processing liquid. Each of the plurality of ink head arrays includes a plurality of ink heads arranged in a manner arranged along the main scanning direction, each of which ejects ink for image formation. When the head closest to one end side among the multiple ink heads, the pre-processing heads and the post-processing heads in the main scanning direction is called the one end side head, the head closest to the other end side is called the other end side head, the distance from the one end side head to the other end side head in the main scanning direction is LC, the distance from the one end side head to the pre-processing head in the main scanning direction is B1, and the distance from the one end side head to the post-processing head in the main scanning direction is B2, the pre-processing head and the post-processing head are arranged in a manner that satisfies the relationship of Formula 1.

[0277] 1 / 2≤(B1+B2) / LC≤3 / 2 (Formula 1)

[0278] This configuration enables a multifunctional, all-in-one inkjet recording device to be mounted on a single carriage, with three heads for discharging pre-treatment liquid, ink, and post-treatment liquid. Furthermore, because the pre-treatment head, ink head, and post-treatment head are sequentially arranged in the conveyance direction, the pre-treatment liquid, ink, and post-treatment liquid can be deposited onto the recording medium in a desired order. Furthermore, by appropriately arranging the pre-treatment head and post-treatment head to satisfy Equation 1, the time difference between the landing of the pre-treatment liquid and the landing of the post-treatment liquid can be minimized, regardless of the carriage's direction of movement. As a result, variations in image quality on the recording medium are less likely to occur.

[0279] In the above configuration, at least one of the front processing head and the post-processing head may include a plurality of processing heads arranged in the main scanning direction, and at least one of the plurality of processing heads may be arranged so as to satisfy the relationship of Formula 1.

[0280] According to this configuration, even when at least one of the pre-processing heads and the post-processing heads is provided in plurality, the difference in time from the landing of the pre-processing liquid to the landing of the post-processing liquid can be reduced by configuring at least one of the pre-processing heads to satisfy Formula 1. Furthermore, since the processing liquid can also be ejected from the other processing heads, the amount of the processing liquid that can be ejected can be increased.

[0281] In the above configuration, all of the plurality of processing heads may be arranged so as to satisfy the relationship of Expression 1.

[0282] According to this configuration, multiple processing heads of at least one of the pre-processing head and the post-processing head are configured in a manner that satisfies Formula 1, thereby further reducing the time difference from the landing of the pre-processing liquid to the landing of the post-processing liquid, and increasing the amount of processing liquid that can be sprayed.

[0283] In addition, another aspect of the present invention relates to an inkjet recording device that includes a conveying unit, a carriage, one or more ink head columns, a pre-processing head, and a post-processing head. The conveying unit conveys the recording medium along a specified conveying direction. The carriage moves back and forth along a main scanning direction that intersects the conveying direction. The one ink head column is mounted on the carriage at a specified position in the conveying direction. The multiple ink head columns are mounted on the carriage in a manner arranged along the conveying direction, and the multiple ink head columns are an odd number of ink head columns. The pre-processing head is arranged on the upstream side of the one or more ink head columns in the conveying direction and ejects a non-colored pre-processing liquid. The post-processing head is arranged on the downstream side of the one or more ink head columns in the conveying direction and ejects a non-colored post-processing liquid. Each of the one or more ink head columns includes a plurality of ink heads that are arranged in a manner arranged along the main scanning direction and eject ink for image formation. When the head closest to one end side among the multiple ink heads, the pre-processing heads and the post-processing heads in the main scanning direction is the one end side head, the head closest to the other end side is the other end side head, the distance from the one end side head to the other end side head in the main scanning direction is LC, the distance from the one end side head to the pre-processing head in the main scanning direction is B1, and the distance from the one end side head to the post-processing head in the main scanning direction is B2, the pre-processing head and the post-processing head are configured in a manner that satisfies the relationship of Formula 2.

[0284] |(B1-B2) / LC |≤1 / 2 (Formula 2)

[0285] According to this configuration, a multifunctional all-in-one inkjet recording device can be provided in which three types of heads for ejecting pre-treatment liquid, ink and post-treatment liquid are mounted on a carriage. In addition, since the pre-treatment head, ink head and post-treatment head are sequentially arranged in the conveying direction, the pre-treatment liquid, ink and post-treatment liquid can be placed in the desired landing order on the recording medium. Moreover, by appropriately arranging the pre-treatment head and post-treatment head in a manner that satisfies Formula 2, the time difference from the landing of the pre-treatment liquid to the landing of the post-treatment liquid can be reduced regardless of the moving direction of the carriage. As a result, it is difficult for image quality differences to occur on the recording medium. In addition, the above-mentioned time difference can be reduced not only when the conveying spacing of the usual recording medium is one head spacing, but also when the head spacing is 1 / n (n is an odd number).

[0286] In the above configuration, at least one of the front processing head and the post-processing head may include a plurality of processing heads arranged in the main scanning direction, and at least one of the plurality of processing heads may be arranged so as to satisfy the relationship of Formula 2.

[0287] According to this configuration, even when at least one of the pre-processing heads and the post-processing heads is provided in plurality, the difference in time from the landing of the pre-processing liquid to the landing of the post-processing liquid can be reduced by configuring at least one of the pre-processing heads to satisfy Formula 2. Furthermore, since the processing liquid can also be ejected from the other processing heads, the amount of the processing liquid that can be ejected can be increased.

[0288] In the above configuration, all of the plurality of processing heads may be arranged so as to satisfy the relationship of Expression 2.

[0289] According to this configuration, multiple processing heads of at least one of the pre-processing head and the post-processing head are configured in a manner that satisfies Formula 2, thereby further reducing the time difference from the landing of the pre-processing liquid to the landing of the post-processing liquid and increasing the amount of processing liquid that can be sprayed.

[0290] In the above configuration, the pre-processing head and the post-processing head may be arranged within a range of an arrangement width of the plurality of ink heads in the main scanning direction.

[0291] According to this inkjet recording apparatus, even when the processing head is mounted on the carriage, there is no need to increase the width of the carriage in the main scanning direction.

[0292] In the above-described configuration, at least one of the pre-processing head and the post-processing head may be configured so that a portion thereof enters between a pair of ink heads, wherein the pair of ink heads is a pair of ink heads that are adjacent in the main scanning direction among the plurality of ink heads included in one of the ink head columns.

[0293] According to this inkjet recording apparatus, ink heads and processing heads arranged at different positions in the transport direction (sub-scanning direction) can be arranged at high density in the transport direction, thereby miniaturizing the width of the carriage in the transport direction.

[0294] In the described configuration, the pre-processing head and the post-processing head may be arranged in such a manner that a part of them is adjacent to the ink head in the main scanning direction and the conveying direction, and the plurality of ink heads include a plurality of same-color ink heads that eject ink of the same color, and when counting the number of adjacent processing heads in the pre-processing head and the post-processing head in the main scanning direction and the conveying direction for each of the same-color ink heads, the difference between the maximum and minimum values of their count values is less than 1.

[0295] Typically, a head that ejects liquid using a jetting method generates heat because it uses electricity to pressurize the liquid. In particular, unlike an ink head that ejects only when forming dots of a desired color, a processing head that ejects for all colors is more likely to reach high temperatures. Ink heads adjacent to such a processing head are more likely to reach high temperatures, and the amount of ink ejected may differ from that of ink heads not adjacent to the processing head. As described above, by setting the difference between the maximum and minimum counts of each ink head of the same color adjacent to the processing head to less than 1, it is less likely that a large difference in ink ejection volume will occur between multiple ink heads of the same color.

[0296] In the above-described configuration, the pre-processing head and the post-processing head may be arranged in such a manner that a part of them is adjacent to the ink head in the main scanning direction and the conveying direction, and the plurality of ink heads may include at least a first ink head that ejects ink of a first color and a second ink head that ejects ink of a second color. When the total number of the pre-processing heads and the post-processing heads adjacent to the first ink head is greater than the total number of the pre-processing heads and the post-processing heads adjacent to the second ink head, the first ink head ejects ink having a smaller viscosity change due to temperature than the ink of the second color as the ink of the first color.

[0297] According to this inkjet recording device, the first ink head, which has a greater total number of adjacent processing heads, ejects ink whose viscosity changes less with temperature. Therefore, even if the first ink head is heated by the processing head, changes in the ejection volume and ejection speed of the first color ink due to temperature can be reduced.

[0298] In the above configuration, the pre-processing head and the post-processing head may be arranged apart from the plurality of ink heads in the main scanning direction.

[0299] When ink comes into contact with a treatment liquid, for example, ink components may aggregate. If the aggregates adhere to the ink ejection nozzles of the inkjet head, ejection defects may occur. With the inkjet recording device described above, since the treatment head and ink head are separated in the main scanning direction, contact between the ink and treatment liquid on the carriage can be minimized.

[0300] In the above configuration, the carriage may include a first area where the ink head array is arranged and a second area adjacent to the first area in the main scanning direction, and the pre-processing head and the post-processing head may be arranged in the second area.

[0301] According to this inkjet recording device, the pre-processing head, post-processing head, and ink head can be separated in the main scanning direction, thereby making it difficult for the pre-processing liquid and post-processing liquid to come into contact with the ink on the carriage, thereby reducing problems such as aggregation.

[0302] In the above configuration, the pre-processing head and the post-processing head may be respectively arranged in a central region of an arrangement width of the ink head array in the main scanning direction.

[0303] Alternatively, the pre-processing heads and the post-processing heads may be arranged so that the configuration or arrangement center of one or more pre-processing heads in the main scanning direction is consistent with the configuration or arrangement center of one or more post-processing heads in the main scanning direction.

[0304] According to these inkjet recording apparatuses, it is possible to reduce, in particular, the difference in time from when the pre-treatment liquid lands on the recording medium to when the ink lands, and the difference in time from when the ink lands to when the post-treatment liquid lands, at each main scanning position.

[0305] In the inkjet recording device, it can also be that: when the number of the pre-processing heads and the post-processing heads with more heads is set to m and the number of the post-processing heads with less heads is set to n, the requirement of m=n+odd number is satisfied, and the configuration or arrangement center of the pre-processing heads and the post-processing heads is consistent with the configuration position of one of the multiple ink heads in the main scanning direction.

[0306] This inkjet recording device allows the pre-processing head and post-processing head to be mounted on the carriage in a somewhat centralized manner. This reduces the number of inkjet heads positioned close to the processing heads. This reduces the likelihood of pre-processing and post-processing liquids coming into contact with the ink on the carriage.

[0307] The inkjet recording device may also include: a holding component that holds the slide in a state where it can move back and forth along the main scanning direction, wherein the slide has a locking portion, and the slide is held by the holding component in a cantilever state through the locking portion, and in the conveying direction, the front processing head is arranged closer to the locking portion relative to the post-processing head.

[0308] According to this inkjet recording device, the carriage is supported in a cantilevered configuration by a retaining member, thereby enabling a simple structure. Furthermore, by supporting the carriage in a cantilevered configuration, a single-sided structure with the carriage exposed can be easily configured, facilitating maintenance of the inkjet head and processing head. When the carriage is supported in a cantilevered configuration, height accuracy is likely to decrease on the side of the carriage away from the engaging portion. However, since the post-processing head, which has relatively high requirements for ejection accuracy, is mounted on the side away from the engaging portion, this is unlikely to significantly impact image quality.

[0309] The inkjet recording device may also include: a holding component that holds the slide in a state where it can move back and forth along the main scanning direction, wherein the slide has a locking portion, and the slide is held by the holding component in a cantilever state through the locking portion, and the side with fewer heads among the pre-processing head and the post-processing head is arranged on the locking portion side of the slide.

[0310] As described above, the treatment head generates heat during the ejection operation. Consequently, the carriage carrying the treatment head is heated, potentially causing thermal deformation of the carriage and its retaining structure. In a configuration where the carriage is held in a cantilevered position, this thermal deformation can sometimes affect ink placement accuracy. With this configuration, the number of treatment heads positioned near the base end can be reduced, minimizing the impact of thermal deformation.

[0311] The inkjet recording device may also include: a holding component for holding the slide in a state where it can move back and forth along the main scanning direction, wherein the slide has a locking portion, and the slide is held by the holding component in a cantilever state through the locking portion, and the head of the pre-processing head and the post-processing head that is arranged on the side of the locking portion closest to the slide is arranged at a position other than the end of the main scanning direction in the head arrangement body of the pre-processing head, the ink head and the post-processing head.

[0312] According to this inkjet recording device, the head positioned closest to the engaging portion is not positioned at the end of the head array body (head placement area) in the main scanning direction. Generally, the end in the main scanning direction is closest to the end (corner) of the carriage. If thermal deformation occurs near the end of the carriage, i.e., the base end, the positional accuracy of the head mounted on the carriage decreases. This configuration reduces the likelihood of this problem.

[0313] The inkjet recording device may also include: a plurality of ink sub-tanks for supplying the ink to each of the plurality of ink heads in the ink head array; and a plurality of treatment liquid sub-tanks for supplying any one of the pre-treatment liquid and the post-treatment liquid to each of the pre-treatment head and the post-treatment head, wherein the plurality of ink sub-tanks are mounted on the slide in a manner arranged along the main scanning direction, and the plurality of treatment liquid sub-tanks are located at positions different from the plurality of ink sub-tanks in the conveying direction, and are mounted on the slide in a manner arranged along the main scanning direction.

[0314] According to the above configuration, the ink sub-tanks and the processing head sub-tanks are arranged along the main scanning direction at positions different from the heads in the transport direction. This allows the sub-tanks to be arranged within a relatively narrow range on the carriage. Furthermore, the liquid in the sub-tanks, carried on the carriage as it reciprocates in the main scanning direction, is subjected to acceleration in the main scanning direction. The sub-tanks and the heads are connected via prescribed conduits. However, if the sub-tanks are widely distributed on the carriage, the conduit arrangement range in the main scanning direction also increases, thus increasing the effect of the acceleration and potentially causing meniscus damage in the ejection portion of the head. According to the above configuration, the conduit arrangement range in the main scanning direction can be relatively narrow.

[0315] In addition, another aspect of the present invention relates to an inkjet recording method, which is an inkjet recording method of an inkjet recording device. The inkjet recording device includes a conveying unit, a carriage, one or more ink head arrays, a pre-processing head, and a post-processing head. The conveying unit conveys the recording medium along a prescribed conveying direction. The carriage moves back and forth along a main scanning direction intersecting the conveying direction. The one ink head array is mounted on the carriage at a prescribed position in the conveying direction. The multiple ink head arrays are mounted on the carriage in a manner arranged along the conveying direction. The pre-processing head is arranged on the upstream side of the one or more ink head arrays in the conveying direction, and ejects a non-colored pre-processing liquid. The post-processing head is arranged on the downstream side of the one or more ink head arrays in the conveying direction, and ejects a non-colored post-processing liquid. Each of the one or more ink head arrays includes a plurality of ink heads arranged in a manner arranged along the main scanning direction, each of which ejects ink for image formation. The inkjet recording method includes: arranging the pre-processing head so as to satisfy the relationship 1 / 2≤(B1+B2) / LC≤3 / 2 (Formula 1), assuming that among the plurality of ink heads, the pre-processing head, and the post-processing head, the head arranged closest to one end in the main scanning direction is a one end side head, the head arranged closest to the other end is a the other end side head, the distance from the one end side head to the other end side head in the main scanning direction is LC, the distance from the one end side head to the pre-processing head in the main scanning direction is B1, and the distance from the one end side head to the post-processing head in the main scanning direction is B2. and the post-processing head; while moving the slide toward the first direction of the main scanning direction, the pre-processing liquid is ejected from the pre-processing head toward the specified recording area on the recording medium; while transporting the recording medium along the transport direction and moving the slide along the main scanning direction, the ink is ejected from the ink head toward the recording area from which the pre-processing liquid has been ejected; while further transporting the recording medium along the transport direction and moving the slide toward the second direction opposite to the first direction of the main scanning direction, the post-processing liquid is ejected from the post-processing head toward the recording area from which the ink has been ejected.

[0316] According to this method, an image can be effectively formed on a recording medium using a multifunctional all-in-one inkjet recording device in which the ejection heads for the pre-treatment liquid, ink, and post-treatment liquid are all mounted on a single carriage. In particular, since the pre-treatment head, ink head, and post-treatment head are sequentially arranged in the conveying direction, the pre-treatment liquid, ink, and post-treatment liquid can be placed in the desired landing order on the recording medium. Moreover, by appropriately arranging the pre-treatment head and the post-treatment head in a manner that satisfies Formula 1, the pre-treatment head and the post-treatment head move in opposite directions in the main scanning direction for a specified recording area and eject the treatment liquid, thereby reducing the time difference from the landing of the pre-treatment liquid to the landing of the post-treatment liquid. As a result, it is difficult for differences in image quality to occur on the recording medium.

[0317] In particular, according to the above method, when the number of ink head columns in the conveying direction is an even number or when the number of ink head columns in the conveying direction F is an odd number and the conveying spacing of the recording medium is 1 / n head spacing (n is an even number), the time difference from the landing of the pre-treatment liquid to the landing of the post-treatment liquid can be reduced.

[0318] In addition, another aspect of the present invention relates to an inkjet recording method, which is an inkjet recording method of an inkjet recording device. The inkjet recording device includes a conveying unit, a carriage, one or more ink head arrays, a pre-processing head, and a post-processing head. The conveying unit conveys the recording medium along a prescribed conveying direction. The carriage moves back and forth along a main scanning direction intersecting the conveying direction. The one ink head array is mounted on the carriage at a prescribed position in the conveying direction. The multiple ink head arrays are mounted on the carriage in a manner arranged along the conveying direction. The pre-processing head is arranged on the upstream side of the one or more ink head arrays in the conveying direction, and ejects a non-colored pre-processing liquid. The post-processing head is arranged on the downstream side of the one or more ink head arrays in the conveying direction, and ejects a non-colored post-processing liquid. Each of the one or more ink head arrays includes a plurality of ink heads arranged in a manner arranged along the main scanning direction, each of which ejects ink for image formation. The inkjet recording method includes: assuming that among the plurality of ink heads, the pre-processing head, and the post-processing head, the head closest to one end side in the main scanning direction is a one end side head, the head closest to the other end side is a the other end side head, the distance from the one end side head to the other end side head in the main scanning direction is LC, the distance from the one end side head to the pre-processing head in the main scanning direction is B1, and the distance from the one end side head to the post-processing head in the main scanning direction is B2, so as to satisfy |(B1-B2) / LC|≤1 / 2 The pre-processing head and the post-processing head are configured in a manner in accordance with the relationship of (Formula 2); while the carriage is moved toward the first direction of the main scanning direction, the pre-processing liquid is ejected from the pre-processing head toward a specified recording area on the recording medium; while the recording medium is transported along the transport direction and the carriage is moved along the main scanning direction, the ink is ejected from the ink head toward the recording area to which the pre-processing liquid has been ejected; while the recording medium is further transported along the transport direction and the carriage is moved toward the first direction of the main scanning direction, the post-processing liquid is ejected from the post-processing head toward the recording area to which the ink has been ejected.

[0319] According to this method, an image can be effectively formed on a recording medium using a multifunctional all-in-one inkjet recording device in which three heads for discharging a pre-treatment liquid, ink, and post-treatment liquid are mounted on a carriage. In addition, since the pre-treatment head, ink head, and post-treatment head are sequentially arranged in the conveying direction, the pre-treatment liquid, ink, and post-treatment liquid can be ejected in a manner that forms a desired landing order on the recording medium. Moreover, by appropriately arranging the pre-treatment head and post-treatment head in a manner that satisfies Formula 2, the pre-treatment head and post-treatment head move in the same direction in the main scanning direction and eject the treatment liquid, thereby reducing the time difference from the landing of the pre-treatment liquid to the landing of the post-treatment liquid. As a result, it is difficult for differences in image quality to occur on the recording medium.

[0320] In particular, according to the above method, when the number of ink head columns in the conveying direction is an odd number and the conveying spacing of the recording medium is one head spacing or 1 / n head spacing (n is an odd number), the time difference from the landing of the pre-treatment liquid to the landing of the post-treatment liquid can be reduced.

[0321] According to the present invention, an inkjet recording device and an inkjet recording method can be provided that have a carriage that carries a pre-processing head, an ink head, and a post-processing head and moves along the main scanning direction, and can reduce the time difference from the landing of the pre-processing liquid to the landing of the post-processing liquid.

[0322] Explanation of symbols

[0323] 1 Inkjet printer (ink head recording device)

[0324] 16 Timing belt (moving part)

[0325] 17 Guide rail (holding component)

[0326] 20 Workpiece conveying unit (conveying unit)

[0327] 3. 3A to 3J carriages

[0328] 31 head support frame

[0329] 32 rear frame (locking part)

[0330] 4 ink heads

[0331] 41 First ink head array (ink head array)

[0332] 42 Second ink head row (ink head row)

[0333] 43 Third ink head row (ink head row)

[0334] 4A to 4F: First to sixth ink heads

[0335] 4A1 to 4F1 upstream side head

[0336] 4A2 to 4F2 downstream side head

[0337] 5. Pre-processing head (processing head)

[0338] 6 Post-processing head (processing head)

[0339] 7 secondary containers

[0340] 7A to 7F ink sub-tanks

[0341] 71 Auxiliary container for pretreatment liquid

[0342] 72 Auxiliary container for post-processing liquid

[0343] F Conveying direction

[0344] S Main scanning direction

[0345] W Workpiece (recording medium)

Claims

1. An inkjet recording device, characterized in that include: a conveying portion for conveying the recording medium along a prescribed conveying direction; a carriage reciprocating along a main scanning direction intersecting the conveying direction; a plurality of ink head arrays mounted on the carriage in a manner aligned along the transport direction, wherein the plurality of ink head arrays are an even number of ink head arrays; a pre-processing head disposed upstream of the plurality of ink head arrays in the transport direction and configured to eject a non-colored pre-processing liquid; as well as, The post-processing head is arranged on the downstream side of the plurality of ink head arrays in the transport direction and ejects a non-colored post-processing liquid, wherein Each of the plurality of ink head arrays includes a plurality of ink heads arranged in a row along the main scanning direction and each of which ejects ink for image formation. Assuming that among the plurality of ink heads, the pre-processing heads, and the post-processing heads, the head disposed closest to one end in the main scanning direction is the one end side head, the head disposed closest to the other end is the other end side head, the distance from the one end side head to the other end side head in the main scanning direction is LC, the distance from the one end side head to the pre-processing head in the main scanning direction is B1, and the distance from the one end side head to the post-processing head in the main scanning direction is B2, the pre-processing head and the post-processing head are disposed so as to satisfy the relationship of Formula 1. 1 / 2 ≤ (B1+B2) / LC ≤ 3 / 2 (Formula 1).

2. The inkjet recording device according to claim 1, wherein At least one of the pre-processing head and the post-processing head includes a plurality of processing heads arranged in the main scanning direction, and at least one processing head among the plurality of processing heads is arranged so as to satisfy the relationship of Expression 1.

3. The inkjet recording device according to claim 2, wherein All of the plurality of processing heads are arranged so as to satisfy the relationship of Expression 1.

4. The inkjet recording device according to any one of claims 1 to 3, wherein The pre-processing head and the post-processing head are arranged within a range of an arrangement width of the plurality of ink heads in the main scanning direction.

5. The inkjet recording device according to any one of claims 1 to 3, wherein At least one of the pre-processing head and the post-processing head is arranged so that a portion thereof enters between a pair of ink heads that are adjacent to each other in the main scanning direction among the plurality of ink heads included in one ink head row.

6. The inkjet recording device according to any one of claims 1 to 3, wherein The pre-processing head and the post-processing head are arranged so that a portion thereof is adjacent to the ink head in the main scanning direction and the transport direction. The plurality of ink heads include a plurality of ink heads of the same color that eject ink of the same color, When the number of adjacent processing heads in the main scanning direction and the transport direction among the pre-processing heads and the post-processing heads is counted for each of the same-color ink heads, the difference between the maximum and minimum count values is 1 or less.

7. The inkjet recording device according to any one of claims 1 to 3, characterized in that The pre-processing head and the post-processing head are arranged so that a portion thereof is adjacent to the ink head in the main scanning direction and the transport direction. The plurality of ink heads include at least a first ink head for ejecting ink of a first color and a second ink head for ejecting ink of a second color. When the total number of the pre-processing heads and the post-processing heads adjacent to the first ink head is greater than the total number of the pre-processing heads and the post-processing heads adjacent to the second ink head, the first ink head ejects ink having a smaller viscosity change due to temperature than the ink of the second color as the ink of the first color.

8. The inkjet recording device according to any one of claims 1 to 3, characterized in that The pre-processing head and the post-processing head are arranged to be separated from each other in the main scanning direction.

9. The inkjet recording device according to any one of claims 1 to 3, characterized in that The carriage includes a first area where the ink head array is arranged and a second area adjacent to the first area in the main scanning direction. The pre-processing head and the post-processing head are arranged in the second area.

10. The inkjet recording device according to any one of claims 1 to 3, wherein The pre-processing head and the post-processing head are respectively arranged in a central area of an arrangement width of the ink head array in the main scanning direction.

11. The inkjet recording device according to any one of claims 1 to 3, characterized in that The pre-processing heads and the post-processing heads are arranged so that the arrangement or arrangement center of one or more pre-processing heads in the main scanning direction coincides with the arrangement or arrangement center of one or more post-processing heads in the main scanning direction.

12. The inkjet recording device according to claim 11, wherein When the number of the pre-processing heads and the post-processing heads that has more heads is set to m and the number of the post-processing heads that has less heads is set to n, the condition of m=n+odd number is satisfied. The arrangement or arrangement center of the pre-processing head and the post-processing head coincides with the arrangement position of one of the plurality of ink heads in the main scanning direction.

13. The inkjet recording device according to any one of claims 1 to 3, characterized in that Also includes: A holding member holds the carriage in a state where the carriage can reciprocate along the main scanning direction, wherein The carriage includes an engaging portion, and the carriage is held by the holding member in a cantilevered state via the engaging portion. The pre-processing head is arranged closer to the engaging portion than the post-processing head in the conveying direction.

14. The inkjet recording device according to any one of claims 1 to 3, characterized in that Also includes: A holding member holds the carriage in a state where the carriage can reciprocate along the main scanning direction, wherein The carriage includes an engaging portion, and the carriage is held by the holding member in a cantilevered state via the engaging portion. The pre-processing head and the post-processing head, whichever has a smaller number of heads, is arranged on the engaging portion side of the carriage.

15. The inkjet recording device according to any one of claims 1 to 3, characterized in that Also includes: A holding member holds the carriage in a state where the carriage can reciprocate along the main scanning direction, wherein The carriage includes an engaging portion, and the carriage is held by the holding member in a cantilevered state via the engaging portion. The head of the pre-processing head and the post-processing head that is located closest to the engaging portion of the carriage is arranged at a position other than an end in the main scanning direction in the head array of the pre-processing head, the ink head, and the post-processing head.

16. The inkjet recording device according to any one of claims 1 to 3, characterized in that Also includes: a plurality of ink sub-tanks for supplying the ink to each of the plurality of ink heads of the ink head array; and, A plurality of sub-tanks for processing liquid are used to supply either the pre-processing liquid or the post-processing liquid to each of the pre-processing head and the post-processing head, wherein: The plurality of ink sub-tanks are mounted on the carriage so as to be aligned in the main scanning direction, and the plurality of treatment liquid sub-tanks are mounted on the carriage so as to be aligned in the main scanning direction at positions different from the plurality of ink sub-tanks in the conveying direction.

17. An inkjet recording device, characterized in that include: a conveying portion for conveying the recording medium along a prescribed conveying direction; a carriage reciprocating along a main scanning direction intersecting the conveying direction; one ink head array or a plurality of ink head arrays, the one ink head array being mounted on the carriage at a predetermined position in the conveying direction, the plurality of ink head arrays being mounted on the carriage so as to be aligned in the conveying direction, the plurality of ink head arrays being an odd number of ink head arrays; a pre-treatment head disposed upstream of the one or more ink head arrays in the transport direction and configured to eject a non-colored pre-treatment liquid; as well as, The post-processing head is arranged on the downstream side of the one or more ink head arrays in the conveying direction and ejects a non-colored post-processing liquid, wherein Each of the one or more ink head arrays includes a plurality of ink heads arranged in a row along the main scanning direction and each of which ejects ink for image formation. Assuming that among the plurality of ink heads, the pre-processing heads, and the post-processing heads, the head disposed closest to one end in the main scanning direction is the one end side head, the head disposed closest to the other end is the other end side head, the distance from the one end side head to the other end side head in the main scanning direction is LC, the distance from the one end side head to the pre-processing head in the main scanning direction is B1, and the distance from the one end side head to the post-processing head in the main scanning direction is B2, the pre-processing head and the post-processing head are disposed so as to satisfy the relationship of Formula 2, |(B1−B2) / LC| ≤ 1 / 2 (Equation 2).

18. The inkjet recording device according to claim 17, wherein At least one of the pre-processing head and the post-processing head includes a plurality of processing heads arranged in the main scanning direction, and at least one of the plurality of processing heads is arranged so as to satisfy the relationship of Expression 2.

19. The inkjet recording device according to claim 17 or 18, wherein The pre-processing head and the post-processing head are arranged within a range of an arrangement width of the plurality of ink heads in the main scanning direction.

20. The inkjet recording device according to claim 17 or 18, wherein At least one of the pre-processing head and the post-processing head is arranged so that a portion thereof enters between a pair of ink heads that are adjacent to each other in the main scanning direction among the plurality of ink heads included in one ink head row.

21. The inkjet recording device according to claim 17 or 18, wherein The pre-processing head and the post-processing head are arranged so that a portion thereof is adjacent to the ink head in the main scanning direction and the transport direction. The plurality of ink heads include a plurality of ink heads of the same color that eject ink of the same color, When the number of adjacent processing heads in the main scanning direction and the transport direction among the pre-processing heads and the post-processing heads is counted for each of the same-color ink heads, the difference between the maximum and minimum count values is 1 or less.

22. The inkjet recording device according to claim 17 or 18, wherein The pre-processing head and the post-processing head are arranged so that a portion thereof is adjacent to the ink head in the main scanning direction and the transport direction. The plurality of ink heads include at least a first ink head for ejecting ink of a first color and a second ink head for ejecting ink of a second color. When the total number of the pre-processing heads and the post-processing heads adjacent to the first ink head is greater than the total number of the pre-processing heads and the post-processing heads adjacent to the second ink head, the first ink head ejects ink having a smaller viscosity change due to temperature than the ink of the second color as the ink of the first color.

23. The inkjet recording device according to claim 17 or 18, wherein The pre-processing head and the post-processing head are arranged to be separated from each other in the main scanning direction.

24. The inkjet recording device according to claim 17 or 18, wherein The carriage includes a first area where the ink head array is arranged and a second area adjacent to the first area in the main scanning direction. The pre-processing head and the post-processing head are arranged in the second area.

25. The inkjet recording device according to claim 17 or 18, wherein The pre-processing head and the post-processing head are respectively arranged in a central area of an arrangement width of the ink head array in the main scanning direction.

26. The inkjet recording device according to claim 17 or 18, wherein The pre-processing heads and the post-processing heads are arranged so that the arrangement or arrangement center of one or more pre-processing heads in the main scanning direction coincides with the arrangement or arrangement center of one or more post-processing heads in the main scanning direction.

27. The inkjet recording device according to claim 26, wherein When the number of the pre-processing heads and the post-processing heads that has more heads is set to m and the number of the post-processing heads that has less heads is set to n, the condition of m=n+odd number is satisfied. The arrangement or arrangement center of the pre-processing head and the post-processing head coincides with the arrangement position of one of the plurality of ink heads in the main scanning direction.

28. The inkjet recording device according to claim 17 or 18, characterized in that Also includes: A holding member holds the carriage in a state where the carriage can reciprocate along the main scanning direction, wherein The carriage includes an engaging portion, and the carriage is held by the holding member in a cantilevered state via the engaging portion. The pre-processing head is arranged closer to the engaging portion than the post-processing head in the conveying direction.

29. The inkjet recording device according to claim 17 or 18, characterized in that Also includes: A holding member holds the carriage in a state where the carriage can reciprocate along the main scanning direction, wherein The carriage includes an engaging portion, and the carriage is held by the holding member in a cantilevered state via the engaging portion. The pre-processing head and the post-processing head, whichever has a smaller number of heads, is arranged on the engaging portion side of the carriage.

30. The inkjet recording device according to claim 17 or 18, characterized in that Also includes: A holding member holds the carriage in a state where the carriage can reciprocate along the main scanning direction, wherein The carriage includes an engaging portion, and the carriage is held by the holding member in a cantilevered state via the engaging portion. The head of the pre-processing head and the post-processing head that is located closest to the engaging portion of the carriage is arranged at a position other than an end in the main scanning direction in the head array of the pre-processing head, the ink head, and the post-processing head.

31. The inkjet recording device according to claim 17 or 18, characterized in that Also includes: a plurality of ink sub-tanks for supplying the ink to each of the plurality of ink heads of the ink head array; and, A plurality of sub-tanks for processing liquid are used to supply either the pre-processing liquid or the post-processing liquid to each of the pre-processing head and the post-processing head, wherein: The plurality of ink sub-tanks are mounted on the carriage so as to be aligned in the main scanning direction, and the plurality of treatment liquid sub-tanks are mounted on the carriage so as to be aligned in the main scanning direction at positions different from the plurality of ink sub-tanks in the conveying direction.

32. An inkjet recording method, which is an inkjet recording method using an inkjet recording device, wherein: The inkjet recording device comprises: a conveying portion for conveying the recording medium along a prescribed conveying direction; a carriage reciprocating along a main scanning direction intersecting the conveying direction; one ink head array or a plurality of ink head arrays, the one ink head array being mounted on the carriage at a predetermined position in the transport direction, and the plurality of ink head arrays being mounted on the carriage so as to be aligned in the transport direction; a pre-processing head disposed upstream of the one or more ink head arrays in the transport direction and configured to eject a non-colored pre-processing liquid; and The post-processing head is arranged on the downstream side of the one or more ink head arrays in the conveying direction and ejects a non-colored post-processing liquid, wherein Each of the one or more ink head arrays includes a plurality of ink heads arranged in a row along the main scanning direction and each of which ejects ink for image formation. The inkjet recording method is characterized in that: Assuming that among the plurality of ink heads, the pre-processing heads, and the post-processing heads, the head disposed closest to one end in the main scanning direction is the one end side head, the head disposed closest to the other end is the other end side head, the distance from the one end side head to the other end side head in the main scanning direction is LC, the distance from the one end side head to the pre-processing head in the main scanning direction is B1, and the distance from the one end side head to the post-processing head in the main scanning direction is B2, the pre-processing heads and the post-processing heads are disposed so as to satisfy the relationship of Formula 1, 1 / 2 ≤ (B1 + B2) / LC ≤ 3 / 2 (Formula 1); while moving the carriage in a first direction of the main scanning direction, ejecting the pre-treatment liquid from the pre-treatment head toward a predetermined recording area on the recording medium; while conveying the recording medium in the conveying direction and moving the carriage in the main scanning direction, the ink is ejected from the ink head toward the recording area to which the pre-treatment liquid has been ejected; While the recording medium is further transported in the transport direction and the carriage is moved in a second direction opposite to the first direction of the main scanning direction, the post-processing liquid is ejected from the post-processing head toward the recording area to which the ink has been ejected.

33. An inkjet recording method, which is an inkjet recording method using an inkjet recording device, wherein: The inkjet recording device comprises: a conveying portion for conveying the recording medium along a prescribed conveying direction; a carriage reciprocating along a main scanning direction intersecting the conveying direction; one ink head array or a plurality of ink head arrays, the one ink head array being mounted on the carriage at a predetermined position in the transport direction, and the plurality of ink head arrays being mounted on the carriage so as to be aligned in the transport direction; a pre-processing head disposed upstream of the one or more ink head arrays in the transport direction and configured to eject a non-colored pre-processing liquid; and The post-processing head is arranged on the downstream side of the one or more ink head arrays in the conveying direction and ejects a non-colored post-processing liquid, wherein Each of the one or more ink head arrays includes a plurality of ink heads arranged in a row along the main scanning direction and each of which ejects ink for image formation. The inkjet recording method is characterized in that: Assuming that among the plurality of ink heads, the pre-processing heads, and the post-processing heads, the head disposed closest to one end in the main scanning direction is the one end side head, the head disposed closest to the other end is the other end side head, the distance from the one end side head to the other end side head in the main scanning direction is LC, the distance from the one end side head to the pre-processing head in the main scanning direction is B1, and the distance from the one end side head to the post-processing head in the main scanning direction is B2, the pre-processing heads and the post-processing heads are disposed so as to satisfy the relationship of Formula 2. |(B1−B2) / LC| ≤ 1 / 2 (Equation 2); while moving the carriage in a first direction of the main scanning direction, ejecting the pre-treatment liquid from the pre-treatment head toward a predetermined recording area on the recording medium; while conveying the recording medium in the conveying direction and moving the carriage in the main scanning direction, the ink is ejected from the ink head toward the recording area to which the pre-treatment liquid has been ejected; While the recording medium is further transported in the transport direction and the carriage is moved in the first direction in the main scanning direction, the post-processing liquid is ejected from the post-processing head toward the recording area to which the ink has been ejected.

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