Inkjet recording apparatus

Abstract

An inkjet recording apparatus is provided. An inkjet recording apparatus includes a conveyance section, a carriage, one or more ink head rows, and a processing head. The processing head includes a pre-processing head that is disposed on an upstream side with respect to the one or more ink head rows in the conveyance direction and that ejects a non-colored pre-processing liquid. The head disposed closest to one end side in the main scanning direction is set as one end-side head, the head disposed closest to the other end side is set as the other end-side head, and the distance from the one end-side head to the other end-side head in the main scanning direction is set as LC. When the distance from the one-end-side head to the pre-processing head in the main scanning direction is B1, the relationship (B1-LC / 2) / LC < = 1 / 4 is satisfied.

Description

[0001] This application is a divisional application of the invention patent application filed on November 24, 2021, with application number 202180079520.4 and invention title "Inkjet Recording Device". Technical Field

[0002] The present invention relates to an inkjet recording apparatus having an inkjet printhead mounted on a carriage that moves along the main scanning direction. Background Technology

[0003] Inkjet printers and other inkjet recording devices include an ink head that ejects ink for image formation toward a recording medium. For example, when the recording medium is a sheet of fiber such as woven or knitted fabric or a plastic sheet, it is sometimes necessary to apply a pretreatment solution and a posttreatment solution to the recording medium before and after ink is sprayed onto it (e.g., Patent Document 1). The pretreatment solution is, for example, a treatment solution used to improve the fixing properties of the ink on the recording medium and the aggregation properties of the ink pigment. The posttreatment solution is, for example, a treatment solution used to improve the durability of the printed image. In this case, the inkjet recording device includes not only an ink head but also a processing head that ejects the pretreatment solution and the posttreatment solution.

[0004] When the recording medium is wide-format, the aforementioned printhead and processing heads are mounted on a carriage that reciprocates along the main scanning direction. During recording processing, the recording medium is intermittently transported along a predetermined transport direction (sub-scanning direction), and when the recording medium stops, the carriage reciprocates along the main scanning direction. As the carriage moves, ink and processing fluid are ejected from the printhead and processing heads, respectively.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Publication No. 2019-147307 Summary of the Invention

[0008] One aspect of the present invention relates to an inkjet recording apparatus comprising a transport unit, a carriage, one or more printhead arrays, and a processing head. The transport unit transports a recording medium along a predetermined transport direction. The carriage reciprocates along a main scanning direction intersecting the transport direction. The one or more printhead arrays are mounted on the carriage at predetermined positions along the transport direction. The processing head is mounted on the carriage for ejecting a non-coloring processing liquid. Each of the one or more printhead arrays includes multiple printheads arranged in a manner along the main scanning direction for ejecting ink for image formation. The processing head includes a pre-processing head positioned upstream of the one or more printhead arrays along the transport direction for ejecting a pre-processing liquid, which is the processing liquid. In the case that among the plurality of printheads and the processing head, the head closest to one end in the main scanning direction is designated as the one-end head, the head closest to the other end is designated as the other-end head, the distance from the one-end head to the other end head in the main scanning direction is LC, and the distance from the one-end head to the pre-processing head in the main scanning direction is B1, the pre-processing head is configured in a manner that satisfies the relationship of Equation 1.

[0009] |(B1-LC / 2)| / LC≤1 / 4 (Equation 1)

[0010] Furthermore, another aspect of the present invention relates to an inkjet recording apparatus comprising a transport unit, a carriage, one or more printhead arrays, and a processing head. The transport unit transports a recording medium along a predetermined transport direction. The carriage reciprocates along a main scanning direction intersecting the transport direction. The one or more printhead arrays are mounted on the carriage at predetermined positions along the transport direction. The processing head is mounted on the carriage for ejecting a non-coloring processing liquid. Each of the one or more printhead arrays includes multiple printheads arranged in a manner along the main scanning direction for ejecting ink for image formation. The processing head includes a post-processing head disposed downstream of the one or more printhead arrays along the transport direction for ejecting a post-processing liquid, which is the processing liquid. In the case that among the plurality of printheads and the processing head, the head closest to one end in the main scanning direction is designated as the one-end head, the head closest to the other end is designated as the other-end head, the distance from the one-end head to the other end head in the main scanning direction is LC, and the distance from the one-end head to the post-processing head in the main scanning direction is B2, the post-processing head is configured in a manner that satisfies the relationship of Equation 2.

[0011] |(B2-LC / 2)| / LC≤1 / 4 (Equation 2) Attached Figure Description

[0012] Figure 1 This is a perspective view showing the overall structure of an inkjet printer according to an embodiment of the present invention.

[0013] Figure 2 yes Figure 1 A schematic cross-sectional view of line II-II.

[0014] Figure 3 yes Figure 1 The image shows an enlarged 3D view of the carriage.

[0015] Figure 4 This is a schematic diagram illustrating the serial printing method used in this embodiment.

[0016] Figure 5A This is a schematic diagram showing the printing status of the carriage on the forward path and the backward path.

[0017] Figure 5B This is a schematic diagram showing the printing status of the carriage on the outgoing and returning paths.

[0018] Figure 6 This is a top view that schematically illustrates the head configuration involved in Embodiment 1. Figure 3 The configuration of the printhead and processing head in the carriage is shown.

[0019] Figure 7 This is a schematic diagram used to illustrate the landing time of point P on the recording medium for pretreatment liquid, ink, and posttreatment liquid.

[0020] Figure 8 This is a top view showing the carriage with the head configuration involved in Embodiment 2.

[0021] Figure 9 This is a top view showing the carriage with the head configuration involved in Embodiment 3.

[0022] Figure 10 This is a top view showing the carriage with the head configuration involved in Embodiment 4.

[0023] Figure 11 This is a top view showing the carriage with the head configuration involved in Embodiment 5.

[0024] Figure 12 This is a top view showing the carriage with the head configuration involved in Embodiment 6.

[0025] Figure 13 This is a top view showing the carriage with the head configuration according to Embodiment 7.

[0026] Figure 14 This is a top view showing the carriage with the head configuration according to Embodiment 8.

[0027] Figure 15 This is a top view showing the carriage with the head configuration and the sub-container configuration according to Embodiment 9.

[0028] Figure 16 This is a top view showing the carriage with the head configuration involved in Embodiment 10.

[0029] Figure 17 This is a top view showing the carriage with the head configuration according to Embodiment 11.

[0030] Figure 18 This is a top view of the carriage with the head configuration involved in Comparative Example 1, which is compared with the present invention.

[0031] Figure 19 This is a top view of the carriage with the head configuration involved in Comparative Example 2, which is compared with the present invention. Detailed Implementation

[0032] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In this embodiment, as a specific example of an inkjet recording apparatus, an inkjet printer equipped with an inkjet head that ejects ink for image formation toward a wide and long recording medium is illustrated. The inkjet printer of this embodiment is suitable for digital printing, which prints images such as text and patterns onto a recording medium made of materials such as woven fabrics and knitted fabrics by inkjet printing. Of course, the inkjet recording apparatus of the present invention can also be used for printing various inkjet images on recording media such as paper and resin sheets.

[0033] [Overall structure of an inkjet printer]

[0034] Figure 1 This 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 A schematic cross-sectional view along line II-II. The inkjet printer 1 is a printer that prints images on a wide and long workpiece W (recording medium) using inkjet technology. It includes a device frame 10, a workpiece transport section 20 (transport section) assembled to the device frame 10, and a carriage 3. Furthermore, 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 secondary scanning direction (the transport direction F of the workpiece W).

[0035] The device frame 10 forms a skeleton for mounting the various components of the inkjet printer 1. The workpiece transport unit 20 is a mechanism that intermittently transports the workpiece W in a back-to-forward transport direction F within the printing area where inkjet printing is performed. The carriage 3 carries the printhead 4, the pre-processing head 5, the post-processing head 6, and the auxiliary container 7, and reciprocates in the left-right direction during the inkjet printing process.

[0036] The device frame 10 includes a central frame 111, a right frame 112, and a left frame 113. The central frame 111 forms a skeleton for mounting various components of the inkjet printer 1 and has a width corresponding to the left and right sides of the workpiece transport section 20. The right frame 112 and the left frame 113 are respectively erected on the right and left sides of the central frame 111. Between the right frame 112 and the left frame 113 is the printing area 12 for printing the workpiece W.

[0037] The right frame 112 forms a maintenance area 13. Maintenance area 13 is the area where the carriage 3 retracts when the printing process is not being performed. In maintenance area 13, cleaning and wiping of the nozzles (ejection holes) of the printhead 4, preprocessing head 5, and postprocessing head 6 are performed, and the area is then covered. The left frame 113 forms a fold-back area 14 for the carriage 3. Fold-back area 14 is the area where the carriage 3, which performs the main scan of the printing area 12 from right to left during the printing process, temporarily enters when performing a reverse main scan.

[0038] A carriage guide 15 for reciprocating movement of the carriage 3 in the left-right direction is assembled on the upper side of the device frame 10. The carriage guide 15 is a flat plate-shaped component that is elongated in the left-right direction and is disposed above the workpiece transport section 20. A timing belt 16 (moving component) is assembled on the carriage guide 15 in a manner that allows it to rotate circumferentially in the left-right direction (main scanning direction). The timing belt 16 is an annular belt that is driven by a drive source (not shown) to rotate circumferentially in the left or right direction.

[0039] A pair of upper and lower guide rails 17, serving as retaining members for the carriage 3, are provided on the carriage guide 15 in a parallel manner extending in the left-right direction. The carriage 3 engages with the guide rails 17. Furthermore, the carriage 3 is fixed to the timing belt 16. As the timing belt 16 rotates circumferentially to the left or right, the carriage 3 is guided by the guide rails 17 and moves to the left or right along the carriage guide 15.

[0040] Main reference Figure 2 The workpiece conveying unit 20 includes a feed roller 21 for feeding out the workpiece W before printing and a take-up roller 22 for winding up the workpiece W after printing. The feed roller 21 is located at the lower rear of the device frame 10 and is the winding shaft for the workpiece W before printing, i.e., the feed roll WA. The take-up roller 22 is located at the lower front of the device frame 10 and is the winding shaft for the workpiece W after printing, i.e., the take-up roll WB. A first motor M1 is attached to the take-up roller 22 to drive it to rotate around its axis and perform the winding action of the workpiece W.

[0041] The path between the feed roller 21 and the take-up roller 22, passing through the printing area 12, forms the transport path for the workpiece W. Along this transport path, from upstream, a first tension roller 23, a workpiece guide 24, a transport roller 25, a pinch roller 26, a return roller 27, and a second tension roller 28 are sequentially arranged. The first tension roller 23 applies a predetermined tension to the workpiece W upstream of the transport roller 25. The workpiece guide 24 changes the transport direction of the workpiece W from upward to forward, allowing the workpiece W to enter the printing area 12.

[0042] The conveyor roller 25 is a roller that generates a conveying force to intermittently convey the workpiece W in the printing area 12. Driven by a second motor M2, the conveyor roller 25 rotates about its axis, intermittently conveying the workpiece W forward (in the prescribed conveying direction F) through the printing area 12 (image forming position) facing the carriage 3. A pinch roller 26 is positioned above the conveyor roller 25, forming a conveying gap together with the conveyor roller 25.

[0043] The return roller 27 changes the transport direction of the workpiece W, which has passed through the printing area 12, from forward to downward, guiding the printed workpiece W to the take-up roller 22. The second tension roller 28 applies a predetermined tension to the workpiece W on the downstream side of the transport roller 25. In the printing area 12, a platen 29 is arranged below the transport path of the workpiece W.

[0044] The carriage 3, cantilevered by the guide rail 17, reciprocates in the main scanning direction (left-right direction in this embodiment) which intersects (is perpendicular to) the transport direction F. The carriage 3 includes a carriage frame 30, a printhead 4 mounted on the carriage frame 30, a pre-processing head 5, a post-processing head 6, and a secondary container 7. The carriage frame 30 includes a head support frame 31 and a rear frame 32 (engaging part).

[0045] The head support frame 31 is a horizontal plate that holds the heads 4 to 6 as described above. The rear frame 32 is a vertical plate extending 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. Furthermore, the guide rail 17 engages with the rear frame 32. That is, in this embodiment, the rear frame 32 is held in a cantilevered state by the guide rail 17. The head support frame 31 is a horizontal plate whose rear end is supported in a cantilevered state by the engaging portion.

[0046] Furthermore, the cantilever state indicates that in carriage 3, the engaging portion (rear frame 32) exists only on one side of carriage 3, upstream or downstream of the center, in the transport direction F, and there are no other engaging portions on the opposite side of the side where the engaging portion exists. The engaging portion is held by the guide rail 17, which serves as a holding member. The engaging portion can also be positioned outside the range where the printhead 4 and processing head are positioned in the transport direction F. That is, the engaging portion can also be positioned only upstream or downstream of the range where the printhead 4 and processing head are positioned in the transport direction F.

[0047] [Detailed structure of the carriage]

[0048] Further explanation is needed regarding carriage 3. Figure 3 yes Figure 1 An enlarged perspective view of the carriage 3 shown. Figure 3 The diagram shows the conveying direction F (sub-scanning direction) of the workpiece W and the main scanning direction S, which is the moving direction of the carriage 3. Figure 3 The illustration shows an example of multiple ink heads 4 that eject ink for image formation onto a workpiece W, a pre-processing head 5 and a post-processing head 6 that eject non-coloring processing liquid, and multiple auxiliary containers 7 that supply the ink and processing liquid to these heads 4 to 6, mounted on a carriage 3.

[0049] Each printhead 4 includes: multiple nozzles (ink ejection orifices) that eject ink droplets by means of, for example, piezoelectric ejection using a piezoelectric element or thermal ejection using a heating element; and an ink channel that guides the ink to the nozzles. As the ink, for example, an aqueous pigment ink containing an aqueous solvent, pigment, and binder resin can be used. In this embodiment, the multiple printheads 4 include first to sixth printheads 4A to 4F that eject six different colors of ink. For example, the first printhead 4A ejects orange (second color) ink, the second printhead 4B ejects green (second color) ink, the third printhead 4C ejects yellow (first color) ink, the fourth printhead 4D ejects red (first color) ink, the fifth printhead 4E ejects blue (first color) ink, and the sixth printhead 4F ejects black (second color) ink.

[0050] The printheads 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 printhead 4A to 4F of each color has two heads. For example, the first printhead 4A includes an upstream side head 4A1 disposed on the upstream side in the transport direction F; and a downstream side head 4A2 disposed on the downstream side relative to the upstream side head 4A1 and offset to the left in the main scanning direction S. The other printheads 4B to 4F are the same. The upstream side heads of these printheads 4B to 4F are arranged in a row with the upstream side head 4A1 at the same position in the transport direction F along the main scanning direction S, and the downstream side heads are arranged in a row with the downstream side head 4A2 at the same position in the transport direction F along the main scanning direction S.

[0051] With this configuration, the printheads 4 that eject ink of one color are concentrated in the main scanning direction S. Specifically, all the printheads 4 that eject one color, mounted on the carriage 3, are arranged such that printheads 4 ejecting other colors are not sandwiched between each other in the main scanning direction S. Alternatively, all the printheads 4 that eject one color, mounted on the carriage 3, can be arranged within a predetermined range in the main scanning direction S, and printheads 4 ejecting other colors can be arranged within that range.

[0052] If there are differences in printing conditions such as landing position and ejection volume between the two printheads 4, the difference in the case of the same color being ejected is more likely to be significant compared to the case of the two printheads 4 ejecting different colors. If the printheads 4 ejecting the same color are concentrated in the main scanning direction S, even if there are differences in printing conditions between the printheads 4, the quality of the printed image can be made less likely to be degraded.

[0053] Pre-processing head 5 and post-processing head 6 are respectively one type of processing head for ejecting the non-coloring processing liquid, which will be described later. Pre-processing head 5 and post-processing head 6 are positioned differently from printhead 4 in the transport direction F. Pre-processing head 5 is positioned upstream of printhead 4 in the transport direction F. Figure 3 The diagram shows an example where a pre-processing head 5 is positioned near the center of the printhead 4 array. Similarly, a post-processing head 6 is positioned downstream of the printhead 4 in the transport direction F. Figure 3 The diagram shows an example in which two post-processing heads 6A and 6B (multiple processing heads) are arranged near the center of the printhead 4 along the main scanning direction S. Various configurations of the printhead 4, pre-processing head 5, and post-processing head 6 on the carriage 3 will be described in detail in Examples 1 to 17 described later.

[0054] Additionally, as used in the above description, the series of heads formed by the printhead 4 and the post-processing head 6 along the main scanning direction S is referred to as a column of heads, or simply a column. A column of heads sometimes also includes the pre-processing head 5. Furthermore, the series of heads formed by the printhead 4, the pre-processing head 5, and the post-processing head 6 along the transport direction F is referred to as a row of heads, or simply a row.

[0055] The pretreatment head 5 is a type of processing head that sprays a pretreatment liquid for performing a prescribed pretreatment on the workpiece W. The pretreatment liquid is sprayed from the pretreatment head 5 towards the workpiece W at a position where ink has not yet been ejected from the printhead 4. The pretreatment liquid is a non-coloring processing liquid that does not exhibit color even when adhering to the workpiece W; for example, it is a processing liquid that improves the fixing properties of the ink on the workpiece W and the aggregation properties of the ink pigment. Such a pretreatment liquid can be a processing liquid in which a binding resin is mixed with a solvent, or a processing liquid in which a positively charged cationic resin is mixed with a solvent.

[0056] The post-processing head 6 is a type of processing head that sprays a post-processing liquid onto the ink-coated workpiece W to perform a prescribed post-processing. The post-processing liquid is sprayed from the post-processing head 6 toward the workpiece W from the position after ink is ejected from the printhead 4. The post-processing liquid is also a non-coloring processing liquid that does not impart color even when adhering to the workpiece W; it is designed to improve the fixing properties and adhesion (resistance to friction and scratching) of the ink image printed on the workpiece W by the printhead 4. Silicone-based processing liquids, etc., can be used as such post-processing liquids. Furthermore, the post-processing liquid and the pre-processing liquid are different processing liquids. Specifically, the post-processing liquid and the pre-processing liquid contain different components.

[0057] Here, "non-coloring processing fluid" refers to a processing fluid that, when printed alone on a recording medium, cannot be perceived by the naked eye as having any color. This includes colors with a chromaticity of 0, such as black, white, and gray. Non-coloring processing fluid is essentially a transparent liquid; however, when observing 1L of processing fluid in its liquid state, it is not completely transparent and sometimes appears slightly whitish. This color is very faint, and when printed alone on a recording medium, it cannot be perceived by the naked eye. Additionally, depending on the type of processing fluid, when printed alone on a recording medium, the recording medium may sometimes exhibit changes such as gloss, but this is not considered coloring.

[0058] In this embodiment, the pretreatment liquid and posttreatment liquid can be sprayed onto almost the entire surface of the workpiece W, or the pretreatment liquid and posttreatment liquid can be selectively sprayed out in the same way as ink, depending on the image being printed.

[0059] Next, we will explain the case where pretreatment and posttreatment solutions are selectively ejected. As described above, for workpiece W where the color is printed according to the image, the pretreatment solution, ink, and posttreatment solution are ejected in the order of pretreatment solution, ink, and posttreatment solution. In this case, the ink can be one color or multiple colors. For parts where no color is printed, that is, parts where no ink is ejected, the pretreatment solution and posttreatment solution are also basically not ejected. In addition, in order to adjust the quality of the printed image, the texture of workpiece W, etc., the selection of the ejection of pretreatment and posttreatment solutions can be made to differ from the ejection of ink.

[0060] An opening 31H is provided at the head configuration location of the head support frame 31. The printheads 4A to 4F, the pre-processing head 5, and the post-processing head 6 are assembled to the head support frame 31 by being embedded in the respective openings 31H. The nozzles configured on the lower end faces of each of the heads 4, 5, and 6 protrude from each opening 31H.

[0061] Sub-containers 7 are supported by carriages 3 on the upper side of heads 4, 5, and 6 via a retaining frame (shown in the diagram). Sub-containers 7 are respectively positioned opposite heads 4, 5, and 6. Ink or processing fluid is supplied to each sub-container 7 from an ink cartridge or main container (shown in the diagram) containing ink and processing fluid. Each sub-container 7 supplies the ink or processing fluid to each head 4, 5, and 6. Sub-containers 7 and heads 4, 5, and 6 are... Figure 3 The middle is through the pipeline (not shown in the diagram) Figure 15 P1, P2, and P3 shown in the diagram are connected.

[0062] As described above, the inkjet printer 1 according to this embodiment is a multi-functional all-in-one printer that mounts a printhead 4, a pre-processing head 5, and a post-processing head 6 on a carriage 3. According to this inkjet printer 1, for example, in the inkjet printing step of digital printing, the pre-processing liquid ejection step and the post-processing liquid ejection step can be performed simultaneously. Therefore, the printing steps can be simplified and the printing apparatus can be miniaturized.

[0063] [Printing Method]

[0064] Next, the printing method performed by the inkjet printer 1 according to this embodiment will be described. The inkjet printer 1 prints the workpiece W in a serial printing mode. Figure 4 This is a schematic diagram illustrating the serial printing method. Figure 4 In the drawing, the preprocessing head 5 and the postprocessing head 6 are omitted, and the carriage 3 is simply drawn.

[0065] When the workpiece W has a wide dimension, printing cannot be performed while the workpiece W is being continuously fed out. The serial printing method involves repeatedly moving the carriage 3 carrying the inkjet heads 4 in the main scanning direction S and intermittently feeding the workpiece W in the transport direction F. Here, the inkjet head 4 is assumed to have a predetermined printing width Pw in the transport direction F. The printing width Pw is approximately equal to the arrangement range of the ink ejection nozzles of the inkjet head 4.

[0066] In addition, Figure 4 And the following explanation Figure 5A , Figure 5B In the diagram, the width of each head in the transport direction F and the printing width Pw are drawn as approximately equal. In reality, the width of each head in the transport direction F is larger than the printing width Pw and the arrangement range of the ejection nozzles.

[0067] Figure 4 The diagram shows the state after the printing of the strip image G1 with a print width Pw has ended, as the carriage 3 moves in the path direction SA of the main scanning direction S. During the main scan in this path direction SA, the transport of the workpiece W stops. After printing the strip image G1, the workpiece W is transported in the transport direction F with a distance equivalent to the print width Pw. At this time, the carriage 3 waits in the fold-back area 14 on the left end. After the workpiece W is transported, the carriage 3 folds back along the return path direction SB, accompanied by the reverse rotation of the timing belt 16. The workpiece W is in a stopped state. Then, as... Figure 4 As shown, carriage 3 moves in the return path direction SB and prints a strip image G2 with a printing width Pw on the upstream side of the strip image G1. The same action is then repeated.

[0068] Figure 5A and Figure 5B This is a schematic diagram showing the printing status of carriage 3 in the outgoing and returning paths. Here, the printhead 4, pre-processing head 5, and post-processing head 6 mounted on carriage 3 are simplified and shown. Printhead 4 includes first, second, third, and fourth printheads 4A, 4B, 4C, and 4D for ejecting inks of different first, second, third, and fourth colors respectively. These first to fourth printheads 4A to 4D are arranged in a row along the main scanning direction S. The pre-processing head 5 is positioned upstream of printhead 4 in the transport direction F, and the post-processing head 6 is positioned downstream of printhead 4. Furthermore, with... Figure 4 Similarly, in the case described above, workpiece W is fed out along the conveying direction F between the outgoing and returning printing paths. The distance traveled in the conveying direction F is the spacing between adjacent heads in the conveying direction F (head spacing). Furthermore, this distance is also the printing width of heads 4, 5, and 6.

[0069] Figure 5AThe image shows the carriage 3 moving in the path direction SA of the main scanning direction S while performing a printing operation (path main scan). Region A4 on the workpiece W is the area faced by the pretreatment head 5 mounted on the uppermost side of the carriage 3. In this path main scan, a pretreatment layer Lpre is formed on region A4 by the pretreatment liquid ejected from the pretreatment head 5.

[0070] Region A3 is a region located downstream of region A4, at a distance of one printhead pitch, and is the region faced by printhead 4. In region A3, a pre-processing layer Lpre has already been formed along the entire length of the main scan direction during the previous return main scan. During this outgoing main scan, inks of the first to fourth colors, sequentially ejected according to the arrangement order of the first to fourth printheads 4A to 4D, are used on the pre-processing layer Lpre in region A3 to form the first, second, third, and fourth ink layers LCA, LCB, LCC, and LCD. Furthermore, for ease of understanding, Figure 5A The illustration shows the fourth to first ink layers (LCD to LCA) being stacked sequentially, but in reality, they are not stacked. Furthermore, the aforementioned pre-processing layer Lpre and the post-processing layer Lpos, described later, are not formed on the workpiece W.

[0071] Region A2 is a region located downstream of region A3 by a distance of one head pitch, and is the region faced by the post-processing head 6 mounted on the downstream side of the carriage 3. On region A2, a pre-processing layer Lpre formed by the previous outgoing main scan and first to fourth ink layers LCA to LCD formed by the previous return main scan have been formed along the entire length of the main scanning direction. In this outgoing main scan, a post-processing layer Lpos is formed on the first to fourth ink layers LCA to LCD in region A2 using post-processing liquid ejected from the post-processing head 6.

[0072] Region A1 is a region located downstream of region A2 by a distance of one head pitch, and is the region where the printing process ends after the carriage 3 has passed through. That is, in region A1, the pre-processing layer Lpre, the first to fourth ink layers LCA to LCD, and the post-processing layer Lpos are formed along the entire length of the main scanning direction.

[0073] Figure 5B Indicates the end Figure 5AAfter the outgoing main scan, the carriage 3 folds back and moves towards the return path direction SB while performing the return main scan. Before this folding-back movement, the workpiece W is conveyed in the transport direction F by a distance of one head pitch. Region A5 on the workpiece W is the region one head pitch upstream of region A4, and is the region faced by the pretreatment head 5 during this return main scan. On region A5, a pretreatment layer Lpre is formed by the pretreatment liquid sprayed from the pretreatment head 5.

[0074] In regions 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 region A4, the first to fourth ink layers LCA to LCD are formed on the pre-processing layer Lpre. In region A3, the post-processing layer Lpos is formed on the first to fourth ink layers LCA to LCD. Region A2 becomes the region where printing processing ends after region A1.

[0075] The reason why printing can be performed in both the outgoing and returning main scans, as described above, is that the pre-processing head 5 and the post-processing head 6 are offset relative to the printhead 4 in the transport direction F. Assuming that the pre-processing head 5, printhead 4, and post-processing head 6 are arranged in this order along the main scan direction S in the carriage 3, printing that allows the pre-processing fluid and post-processing fluid to be ejected in the desired landing order can only be achieved in one of the outgoing or returning main scans. To enable bidirectional printing, a pair of pre-processing heads 5 and post-processing heads 6 must be arranged on both sides of the printhead 4 array. In this case, the width of the carriage 3 in the main scan direction S becomes larger. Since such a configuration is not required in this embodiment, the width of the carriage 3 in the main scan direction S can be reduced.

[0076] Furthermore, by setting multiple columns of printheads 4, the amount of ink falling on the workpiece W can be increased. For example, when there are two columns of printheads 4, printing can be performed as follows: After the first column of printheads 4 forms the first to fourth ink layers LCA to LCD as described above, the workpiece W is transported in the transport direction F by a distance equal to one printhead pitch, and the second column of printheads 4 forms the first to fourth ink layers LCA to LCD. By operating in this way, two layers of ink of each color can be printed on the workpiece W.

[0077] [Various methods of header configuration]

[0078] The following examples illustrate various configurations of the printhead 4, preprocessing head 5, and postprocessing head 6 on the carriage 3 as Examples 1 to 11. Furthermore, the above-mentioned... Figures 1 to 5A , Figure 5BThis diagram illustrates the basic functions of the preprocessing head 5 and the postprocessing head 6. Detailed configurations of the preprocessing head 5 and the postprocessing head 6 in this embodiment will be provided below. Figure 6 This will be explained later.

[0079] <Example 1>

[0080] Figure 6 This is a top view that schematically illustrates the head configuration involved in Embodiment 1. Figure 6 Or to indicate Figure 3 The diagram shows the configuration of the printheads 4, pre-processing heads 5, and post-processing heads 6 (multiple processing heads) on the carriage 3. The carriage 3 is cantilevered by the guide rail 17 at the rear frame 32 (engaging part). The rear frame 32 is positioned upstream of the head support frame 31 in the transport direction F. In the transport direction F, the side of the head support frame 31 with the rear frame 32 is designated as the base end side 311, and the side of the head support frame 31 opposite to the base end side 311 is designated as the distal end side 312. As described, the head support frame 31 of the carriage 3 is equipped with first to sixth printheads 4A to 4F, each ejecting six different colors of ink, the pre-processing head 5, and the post-processing head 6. Each of the printheads 4A to 4F has two units (a total of 12). There is one pre-processing head 5 and two post-processing heads 6.

[0081] The first to sixth printheads 4A to 4F constituting the printhead 4 are arranged in a manner that the central region of the printhead support frame 31 in the transport direction F is arranged along the main scanning direction S. The pre-processing head 5 is positioned approximately at the center of the carriage 3 in the main scanning direction S, upstream of the printhead 4 in the transport direction F and at the base end 311 of the printhead support frame 31. On the other hand, the post-processing head 6 is positioned approximately at the center of the carriage 3 in the main scanning direction S, downstream of the printhead 4 in the transport direction F and at the distal end 312 of the printhead support frame 31. Both the pre-processing head 5 and the post-processing head 6 are positioned near the center of the printhead support frame 31 in the main scanning direction S.

[0082] The first printhead 4A includes an upstream side head 4A1 and a downstream side head 4A2 disposed downstream of the upstream side head 4A1. That is, the upstream side head 4A1 and the downstream side head 4A2 are arranged in the transport direction F. The upstream side head 4A1 is positioned in the central region of the printhead support frame 31 near the base end 311. The downstream side head 4A2 is positioned in the central region of the printhead support frame 31 near the distal end 312. Relative to the upstream side head 4A1, the downstream side head 4A2 is positioned offset to one side (left side) towards the main scanning direction S and partially overlaps with it in the transport direction F. Of course, the upstream side head 4A1 and the downstream side head 4A2 could also be arranged in the same position in the main scanning direction S (a straight line arrangement in the transport direction F). However, the configuration of this embodiment allows for miniaturization of the carriage 3 in the transport direction F.

[0083] The second to sixth printheads 4B to 4F also include the same upstream sideheads 4B1, 4C1, 4D1, 4E1, 4F1 and downstream sideheads 4B2, 4C2, 4D2, 4E2, 4F2 as the upstream sidehead 4A1 and downstream sidehead 4A2 described above. The upstream sideheads 4A1 to 4F1 of the first to sixth printheads 4A to 4F are arranged in a row at predetermined intervals at the same positions in the transport direction F along the main scanning direction S. Similarly, the downstream sideheads 4A2 to 4F2 are also arranged in a row at predetermined intervals at the same positions in the transport direction F along the main scanning direction S. As a result, a portion of the downstream sideheads 4A2 to 4F2 are arranged in a zigzag pattern between the respective configuration intervals of the upstream sideheads 4A1 to 4F1.

[0084] In other words, to describe the structure of the printhead 4 described above, the printhead 4 has multiple printhead rows mounted on the carriage 3 arranged along the transport direction F. Each of these multiple printhead rows contains multiple printheads arranged along the main scanning direction S and respectively ejecting ink for image formation. Figure 6 In the example shown, multiple printhead rows have a first printhead row 41 and a second printhead row 42. The printheads included in the first printhead row 41 are upstream side printheads 4A1, 4B1, 4C1, 4D1, 4E1, and 4F1. The printheads included in the second printhead row 42 are downstream side printheads 4A2, 4B2, 4C2, 4D2, 4E2, and 4F2.

[0085] The preprocessing head 5 is configured such that a portion of it enters between a pair of adjacent printheads in the main scanning direction S. Specifically, the downstream portion of the preprocessing head 5 enters the positional relationship between the upstream head 4C1 of the third printhead 4C and the upstream head 4D1 of the fourth printhead 4D.

[0086] The post-processing head 6 includes a first post-processing head 6A and a second post-processing head 6B arranged in the main scanning direction S. Figure 6 The diagram shows an example where the first and second post-processing heads 6A and 6B are arranged at the same position along the main scanning direction S, spaced apart by a predetermined interval. The first post-processing head 6A is configured such that its upstream portion enters between the downstream side head 4C2 of the third printhead 4C and the downstream side head 4D2 of the fourth printhead 4D. The second post-processing head 6B is configured such that its upstream portion enters between the downstream side head 4D2 and the downstream side head 4E2, and is positioned at the same position as the upstream side head 4D1 along the main scanning direction S. With this configuration, the first and second post-processing heads 6A and 6B are arranged with an overlapping area fa with the downstream side heads 4C2, 4D2, and 4E2 along the transport direction F.

[0087] 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, in order to ensure that there is no gap between the printing width Pw of each column of heads and the printing range Pw of the heads of adjacent columns, each head is configured with an overlapping area fa.

[0088] In addition, unless otherwise specified, in the following areas Figure 6 In all the diagrams, the spacing between adjacent heads (the spacing between the centers of each head) in the main scanning direction S is the same. Similarly, the distance between adjacent heads (the spacing between the centers of each head) in the transport direction F is the same.

[0089] As a result of the above-described head configuration, the pre-processing head 5 and the post-processing head 6 are positioned within the configuration width H of the printhead 4 in the main scanning direction S. The printhead 4 has a configuration width H in the main scanning direction S between the downstream side head 4A2 of the first printhead 4A and the upstream side head 4F1 of the sixth printhead 4F. The pre-processing head 5 is positioned upstream of the printhead 4 within the configuration width H, and the post-processing head 6 is positioned downstream of the printhead 4 within the configuration width H. Particularly in Embodiment 1, the pre-processing head 5 and the post-processing head 6 are located approximately at the center of the entire head arrangement in the main scanning direction S.

[0090] According to the head configuration described in Embodiment 1 above, both the miniaturization of the carriage 3 and the increase in the necessary ink and processing fluid ejection volume can be achieved. Specifically, the pre-processing head 5 and the post-processing head 6 are positioned differently from the printhead 4 in the transport direction F. With this configuration, printheads 4A to 4F, which can increase the necessary ink ejection volume, are arranged in the main scanning direction S, enabling printing processing in both the outgoing and returning main scans, and reducing the width of the carriage required to mount the aforementioned heads 4 to 6 in the main scanning direction. Furthermore, the post-processing head 6 is composed of multiple first and second post-processing heads 6A and 6B, which are arranged in the main scanning direction S. Therefore, even if the ejection volume of the post-processing fluid is insufficient with a single head, the necessary amount can be ejected by arranging multiple post-processing heads 6A and 6B.

[0091] The first to sixth printheads 4A to 4F include upstream side heads 4A1 to 4F1 (first printhead row 41) and downstream side heads 4A2 to 4F2 (second printhead row 42) arranged along the transport direction F (the direction intersecting the arrangement direction of the multiple processing heads). Therefore, even if the number of printheads 4 is increased to increase the ink ejection volume of each color or to achieve multicoloring, the width of the carriage 3 in the main scanning direction is not easily increased.

[0092] The pre-processing head 5 and the post-processing head 6 are configured within the range of the configuration width H of the first to sixth printheads 4A to 4F in the main scanning direction S. Therefore, even when the pre-processing head 5 and the post-processing head 6 are mounted on the carriage 3 in addition to the printhead 4, it is not necessary to increase the width of the carriage 3 in the main scanning direction. In other words, it is possible to prevent the width of the carriage 3 in the main scanning direction from becoming too large.

[0093] The pre-processing head 5 and the post-processing head 6 are configured to partially extend into the spacing between the first to sixth printheads 4A to 4F. Focusing on the first post-processing head 6A, a portion of it extends between a pair of downstream side heads 4C2 and 4D2. This serrated configuration allows for a high-density arrangement of the printheads 4 and processing heads 5 and 6, which are positioned at different locations along the transport direction F. Therefore, it is possible to miniaturize the width of the carriage 3 along the transport direction F.

[0094] In the head configuration of Embodiment 1, a pre-processing head 5 is arranged upstream of the printhead 4 in the transport direction F, and two post-processing heads 6A and 6B are arranged downstream. That is, a multi-functional inkjet printer 1 is provided that mounts the pre-processing liquid, ink, and post-processing liquid ejection heads onto a single carriage 3. Furthermore, since the pre-processing head 5, printhead 4, and post-processing head 6 are sequentially arranged in the transport direction F, the pre-processing liquid, ink, and post-processing liquid can be ejected in a desired landing order in both the outgoing main scan and the returning main scan.

[0095] Furthermore, the carriage 3 is held in a cantilevered state by the guide rail 17 (holding member). Figure 1 The rear frame 32 (engaging part) is held in place. By supporting the carriage 3 in a cantilevered state by the timing belt 16, the structure can be simplified. Furthermore, by supporting it in a cantilevered state, the downstream side of the carriage 3 can be easily configured to be open, making it easy to maintain the print head 4 and the processing heads 5 and 6.

[0096] In the carriage 3, which is supported in a cantilevered state, the pre-processing head 5 is positioned on the base end side 311 (the side near the engaging part) 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 part). Unlike the base end side 311, which is near the rear frame 32 fixed to the timing belt 16, the estimated positional accuracy is reduced on the distal end side 312, which is a free end. However, the post-processing head 6, which has relatively less stringent requirements for ejection accuracy, is mounted on the distal end side 312. Since the post-processing fluid 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 a landing position shift of the same degree as that of the pre-processing fluid. Therefore, even when using the carriage 3, which is supported in a cantilevered state, the image quality is less likely to be degraded.

[0097] <Problems encountered during header configuration>

[0098] As described above, in addition to the printhead 4, the pre-processing head 5, which sprays pre-processing liquid, and the post-processing head 6, which sprays post-processing liquid, are respectively mounted on the carriage 3. As the carriage 3 moves back and forth in the main scanning direction, the pre-processing liquid, ink, and post-processing liquid are sprayed onto the workpiece W in sequence. The time from the landing of the pre-processing liquid to the landing of the ink and the time from the landing of the ink to the landing of the post-processing liquid vary depending on the image position in the main scanning direction S. As a result, there is a problem that the image quality on the workpiece W is prone to be inconsistent.

[0099] For example, when using a pretreatment solution that improves ink aggregation, a longer time from the pretreatment solution's application to the ink's application results in a darker color. Similarly, when using a post-treatment solution that improves adhesion, a longer time from the ink's application to the application of the post-treatment solution also results in a darker color. When printing with these solutions, a longer time from the application of the pretreatment solution to the application of the post-treatment solution results in a darker color. In the case of multiple applications of the same color ink, for pretreatment solutions, the time from the application of the pretreatment solution to the application of the ink after the initial application has a relatively large impact on color density. For post-treatment solutions, the time from the application of the post-treatment solution to the application of the last ink before the application of the post-treatment solution has a relatively large impact on color density.

[0100] To address the problems described above, the inventors have made a new discovery: by appropriately configuring the pre-processing head 5 and the post-processing head 6 on the carriage 3, it is possible to reduce the time difference from the landing of the pre-processing liquid to the landing of the ink, and the time difference from the landing of the ink to the landing of the post-processing liquid, even between different image positions in the main scanning direction S. The following describes the idea behind this new head configuration and examples of its configuration (embodiments).

[0101] <Head Configuration Ideas>

[0102] Figure 7 This is a schematic diagram illustrating the landing time of the pretreatment solution, ink, and posttreatment solution at point P on the workpiece W. Figure 7 In the design, the printing area 12 is positioned in the center, while the maintenance area 13 and the return area 14 are positioned on its left and right sides. As described above, the carriage 3 moves along the main scanning direction S between the maintenance area 13 and the return area 14, thereby ejecting ink, pretreatment liquid, and posttreatment liquid from the printhead 4, pretreatment head 5, and posttreatment head 6 respectively onto the workpiece W. Furthermore, in Figure 7 For ease of explanation, carriage 3 is shown in both maintenance area 13 and return area 14. Hereinafter, the case in which the print head 4 has multiple print head rows and the workpiece W is intermittently transported and printed with a head pitch (the interval between adjacent heads in the transport direction F) will be described as an example.

[0103] exist Figure 7 In this context, multiple printheads included in printhead columns 41 and 42, as well as processing heads (pre-processing head 5 and post-processing head 6), are defined as follows: the head closest to one end in the main scanning direction S is called the "one-end head"; the head closest to the other end is called the "other-end head"; the distance from one-end head to the other end head in the main scanning direction S is LC; the distance from one-end head to the pre-processing head 5 in the main scanning direction S is B1; and the distance from one-end head to a specified printhead (in the main scanning direction S) is... Figure 7The distance from the upstream side head 4D1 of the fourth printhead 4D is K, and the distance from the upstream side head 4D1 to the post-processing head 6 in the main scanning direction S is B2. Figure 7 In the example shown, one end of the printhead is the downstream end 4A2 of the first printhead 4A, and the other end is the upstream end 4F1 of the sixth printhead 4F. Furthermore, the distances LC, K, B1, and B2 can be set based on a portion of each printhead; however, in the following explanation, these distances will be set based on the center of each printhead in the main scanning direction S. Additionally, the one-end and the other-end can be reversed.

[0104] Furthermore, the center of the head in the main scanning direction S is essentially the position of an imaginary line orthogonal to the main scanning direction S, which bisects the area of ​​the planar shape when viewed from above. Depending on the situation, when viewing the head from above, for the smallest convex polygon among all the ejection nozzles containing the head, the position of the imaginary line orthogonal to the main scanning direction S, which bisects the area of ​​that convex polygon, can be taken as the center of the head in the main scanning direction S.

[0105] First, the timing of each liquid landing on point P of the workpiece W within the printing area 12 will be explained. Furthermore, since the moving speed of the carriage 3 is constant, distances will be used in the following explanation. The actual time can be calculated by dividing each distance by the moving speed of the carriage 3. Additionally, it is assumed that point P is located within the printing area 12 at a distance A from the end of the maintenance area 13 side.

[0106] Furthermore, this is considered as the liquid being ejected from the center of the head in the main scanning direction S. Since the nozzles of each head are actually diffusely distributed in the main scanning direction S, this diffusion also affects the landing time. However, since the positional difference of nozzles within a single head in the main scanning direction S is more often than the positional difference of nozzles in different heads in the main scanning direction S, the effect of the head configuration can be estimated as the liquid being ejected from the center of the head in the main scanning direction S.

[0107] Furthermore, to make the explanation easier to understand, it is assumed that the ejection time and the landing time are simultaneous. In reality, the ejection time, which is to ensure that the liquid lands at a specified position within a specified time, is the flight time of the liquid from the head to the workpiece W, which is earlier than the landing time.

[0108] Assuming the one-way travel distance of carriage 3 (the distance from maintenance area 13 to return area 14) is the minimum distance LP+LC required for printing, carriage 3 is configured in maintenance area 13 as the initial position. In this case, during the first movement (movement to the left) of carriage 3 from maintenance area 13 to return area 14, the time T1 for the pretreatment fluid ejected from pretreatment head 5 to land at point P, calculated as distance, can be expressed by the following formula A.

[0109] T1 = A + B1 (Equation A)

[0110] After the pretreatment fluid lands at point P, during the second movement (movement to the right) of the carriage 3 from the return area 14 to the maintenance area 13, ink is ejected from each printhead of the first printhead row 41 toward point P. Furthermore, during the third movement (movement to the left) of the carriage 3 further moving from the maintenance area 13 to the return area 14, ink is ejected from each printhead of the second printhead row 42 toward point P.

[0111] In the above, the time T2 when the red ink (also known as the first ink or the initial ink) falls from the upstream side head 4D1 of the fourth ink head 4D to point P can be represented by the following formula B.

[0112] T2=(LP+LC)+(LP-A)+(LC-K) (Formula B)

[0113] In the above formula B, the first bracket corresponds to the time it takes for the carriage 3 to move from the maintenance area 13 to the return area 14 during the first movement; the second bracket corresponds to the time it takes for the far end of the carriage 3 to reach point P during the second movement; and the third bracket corresponds to the time it takes for the carriage 3 to move further so that the specified printhead reaches point P.

[0114] According to Equations A and B above, the time ΔT from the falling of the pretreatment liquid to the initial falling of the ink at point P can be expressed by the following Equation C.

[0115] ΔT=T2-T1=LP-2A+LC-(B1+K)+LP+LC (Formula C)

[0116] On the other hand, during the printing process of workpiece W, the carriage 3 sometimes moves first from the fold-back area 14, that is, as the first moving action, it moves to the right. At this time, as described above, the time ΔT from the landing of the pretreatment liquid at point P to the first (initial) landing of the red ink can be expressed by the following formula D.

[0117] ΔT=2A-LP-(LC-(B1+K))+(LP+LC) (Formula D)

[0118] Here, we study all points on the workpiece W in the printing area 12. Since we can assume that the distance A changes from 0 to LP, the range involved in ΔT can be represented by the following equations E, F, and G, according to the above equations C and D.

[0119] ΔTmin1≤ΔT≤ΔTmax1 (Equation E)

[0120] ΔTmin1=-LP-|(LC-(B1+K)|+(LP+LC) (Formula F)

[0121] ΔTmax1=LP+|(LC-(B1+K)|+(LP+LC) (Formula G)

[0122] Next, using the same idea as above, we will explain the time ΔT from the landing of the red ink (also known as the second ink or the final ink) ejected from the downstream side head 4D2 of the fourth printhead 4D at point P until the after-treatment liquid lands. In the case where the first movement moves to the left from the maintenance area 13 towards the return area 14, the time ΔT from the landing of the red ink from the downstream side head 4D2 at point P until the after-treatment liquid lands can be expressed by the following formula H.

[0123] ΔT=LP-2A+(LC-(K+B2))+(LP+LC) (Formula H)

[0124] Furthermore, when the number of printhead rows in printhead 4 is even in the transport direction F, the first ink drop is followed by the second ink drop, as represented by Equation C. On the other hand, when the number of printhead rows in printhead 4 is odd in the transport direction F, the first ink drop is followed by the second ink drop, as represented by Equation D.

[0125] Similarly, when the first movement moves to the right from the return area 14 toward the maintenance area 13, the time ΔT from the landing of the red ink from the downstream head 4D2 at point P to the landing of the post-treatment liquid can be expressed by the following formula I.

[0126] ΔT=2A-LP-(LC-(K+B2))+(LP+LC) (Formula I)

[0127] Furthermore, when the number of printhead columns in printhead 4 is even in the transport direction F, the first ink drop followed by the second ink drop is represented by Equation D. On the other hand, when the number of printhead columns in printhead 4 is odd in the transport direction F, the first ink drop followed by the second ink drop is represented by Equation C.

[0128] Similarly, when studying all points on the workpiece W in the printing area 12, since it can be assumed that the distance A changes from 0 to LP, the range involved in ΔT can be represented by the following equations J, K, and L according to the above equations H and I.

[0129] ΔTmin2≤ΔT≤ΔTmax2 (Equation J)

[0130] ΔTmin2=-LP-|(LC-(K+B2)|+(LP+LC) (Formula K)

[0131] ΔTmax2=LP+|(LC-(K+B2)|+(LP+LC) (Formula L)

[0132] In equations E to G and J to L, to include all printhead configurations, K ranges from 0 to LC. Therefore, when the absolute values ​​of LC-(B1+K) and LC-(K+B2) are relatively small, colors with large time differences of ΔT can be suppressed. That is, the closer B1 and B2 are to LC / 2, the more effectively the aforementioned colors with large time differences can be suppressed. Considering only the landing time, it is optimal that both B1 and B2 are LC / 2.

[0133] Furthermore, the inventors conducted repeated research experiments and explorations, and found that when Equation 1 is satisfied, regardless of the direction of movement of the carriage 3, the time difference between the arrival of the pretreatment liquid and the arrival of the ink on the workpiece W can be reduced, and a stable image can be formed.

[0134] |(B1-LC / 2)| / LC≤1 / 4 (Equation 1)

[0135] Similarly, it was found that when Equation 2 is satisfied, the time difference on the workpiece W from ink application to post-processing liquid application can be reduced, and a stable image can be formed.

[0136] |(B2-LC / 2)| / LC≤1 / 4 (Equation 2)

[0137] Furthermore, when multiple pretreatment heads 5 are configured, it is preferable that at least one pretreatment head 5 is configured in a manner that satisfies Formula 1. As described above, by configuring at least one pretreatment head 5 to satisfy Formula 1, not only can the time difference from the arrival of the pretreatment liquid to the arrival of the ink be reduced, but also the amount of pretreatment liquid that can be ejected can be increased since pretreatment liquid can also be ejected from other pretreatment heads 5.

[0138] Furthermore, it is even more preferable that all of the aforementioned pretreatment heads 5 are configured in a manner that satisfies Formula 1. In this case, the time difference from the arrival of the pretreatment liquid to the arrival of the ink can be further reduced, and the amount of treatment liquid that can be ejected can be increased.

[0139] Similarly, when multiple post-processing heads 6 are configured, it is preferable that at least one post-processing head 6 is configured in a manner that satisfies Equation 2. As described above, by configuring at least one post-processing head 6 to satisfy Equation 2, not only can the time difference from ink landing to post-processing liquid landing be reduced, but also the amount of post-processing liquid that can be ejected can be increased since post-processing liquid can also be ejected from other post-processing heads 6.

[0140] Furthermore, it is even more preferable that all of the aforementioned post-processing heads 6 are configured in a manner that satisfies Equation 2. In this case, the time difference from ink application to post-processing liquid application can be further reduced, and the amount of processing liquid that can be ejected can be increased.

[0141] Furthermore, as Example 1, the carriage 3 is described as having both a pre-processing head 5 and a post-processing head 6 mounted on it. However, the carriage 3 may also have only the pre-processing head 5 or only the post-processing head 6 mounted on it. If Equation 1 is satisfied in the carriage 3 with the printhead 4 and only the pre-processing head 5 mounted on it, the time difference from the arrival of the pre-processing liquid to the arrival of the ink can be reduced. If Equation 2 is satisfied in the carriage 3 with the printhead 4 and only the post-processing head 6 mounted on it, the time difference from the arrival of the ink to the arrival of the pre-processing liquid can be reduced.

[0142] Next, a more preferred configuration of the pre-processing head 5 and post-processing head 6 as specified in Equations 1 and 2 will be described. Examining Equations E to G, the range of ΔT differs between the first to sixth printheads 4A to 4F. That is, the range of ΔT varies depending on the size of K. Figure 7 In the example shown, when B1 > LC / 2, the larger the K value, the greater the range of ΔT variation. In other words, the time difference of black ink in the sixth printhead 4F is the largest among printheads 4. Furthermore, when the first movement moves to the left from the maintenance area 13 towards the return area 14, the time difference of ΔT is smallest at the position A = LP; when the first movement moves to the right from the return area 14 towards the maintenance area 13, the time difference of ΔT is largest at the position A = LP.

[0143] In the above example, because the time difference between the landing of the pretreatment liquid and the landing of the first black ink is large, if the time difference between the landing of the second black ink and the landing of the posttreatment liquid is also large, the difference in image quality between the black image and the images of other colors will be more significant, making the image perceived by the naked eye more susceptible to influence. Therefore, for the sixth printhead 4F, which ejects black ink with a large K value, it is preferable to reduce the time difference between the landing of the second black ink and the landing of the posttreatment liquid. Specifically, it is preferable to configure the posttreatment head 6 with a small B2 value.

[0144] The inventors conducted the same study on each printhead 4 as described above and found that: when multiple printhead rows containing printheads that eject ink of the same color are mounted on the carriage 3 and the printheads 4 are arranged in a concentrated manner in the main scanning direction according to each color, for ink of a specified color, in order to suppress the large time difference from the landing of the pretreatment liquid to the first ink landing and the large time difference from the second ink landing to the landing of the posttreatment liquid, it is effective to set the absolute value of (B1+B2-LC) / LC to be small, preferably satisfying the following formula 3, and more preferably satisfying formula 4.

[0145] |(B1+B2-LC) / LC|≤1 / 2 (Equation 3)

[0146] |(B1+B2-LC) / LC|≤1 / 3 (Equation 4)

[0147] Based on the ideas mentioned above, Figure 6In the printhead configuration with two printhead rows shown in Embodiment 1, the distance LC from the downstream side 4A2 of the first printhead 4A to the upstream side 4F1 of the sixth printhead 4F in the main scanning direction S is 11, the distance B1 from the downstream side 4A2 to the pre-processing head 5 in the main scanning direction S is 6, and the distance B2 from the downstream side 4A2 to each post-processing head 6 in the main scanning direction S is 5 or 7. At this time, |(B1-LC / 2)| / LC = 0.045, satisfying Equation 1 above. Furthermore, |(B2-LC / 2)| / LC = 0.045 or 0.136, both satisfying Equation 2 above. Therefore, the time difference from the landing of the pre-processing liquid to the landing of the ink ejected from the first printhead row 41, and the time difference from the landing of the ink ejected from the second printhead row 42 to the landing of the post-processing liquid can be reduced respectively. As a result, the pretreatment liquid, ink, and posttreatment liquid can be stably and sequentially deposited onto the workpiece W, making it difficult for differences in image quality to occur on the workpiece W. Furthermore, |(B1+B2-LC) / LC| = 0 or 0.18, both satisfying equations 3 and 4 above. Therefore, when multiple printhead rows containing printheads that eject ink of the same color are mounted on the carriage 3, for ink of a specified color, it is possible to suppress large time differences from the deposition of the pretreatment liquid to the first ink deposition and large time differences from the second ink deposition to the deposition of the posttreatment liquid.

[0148] Furthermore, as described above, one of the first post-processing head 6A and the second post-processing head 6B can be configured in a position that does not satisfy equations 1 to 4 above, but the most preferred configuration is as follows: Figure 6 Each of the post-processing heads 6 shown satisfies equations 1 to 4 above.

[0149] <Example 2>

[0150] also, Figure 8This is a top view of the carriage 3A showing the head configuration according to Embodiment 2. In Embodiment 2, the printhead 4 has a first printhead row 41 and a second printhead row 42, and the pre-processing head 5 and the post-processing head 6 are located approximately at the center of the entire head arrangement in the main scanning direction S. In this head configuration, LC=11, B1=6, and B2=5. At this time, |(B1-LC / 2)| / LC=0.045, satisfying Equation 1 above. Furthermore, |(B2-LC / 2)| / LC=0.045, satisfying Equation 2 above. Therefore, the time difference from the landing of the pre-processing liquid to the landing of the ink ejected from the first printhead row 41, and the time difference from the landing of the ink ejected from the second printhead row 42 to the landing of the post-processing liquid can be reduced respectively. Furthermore, |(B1+B2-LC) / LC|=0, satisfying Equations 3 and 4 above. Therefore, when multiple printheads, each containing a printhead that ejects ink of the same color, are mounted on the carriage 3, for ink of a specified color, it is possible to suppress a large time difference from the arrival of the pretreatment liquid to the arrival of the first ink, and a large time difference from the arrival of the second ink to the arrival of the posttreatment liquid.

[0151] <Example 3>

[0152] also, Figure 9 This is a top view showing the carriage 3B of the printhead configuration according to Embodiment 3. In Embodiment 3, the printheads are arranged in a single row. Furthermore, in this Embodiment 3, the pre-processing head 5 and the post-processing head 6 are located approximately at the center of the entire printhead arrangement in the main scanning direction S. Figure 9 In the head configuration, LC=6, B1=3, and B2=3. At this time, |(B1-LC / 2)| / LC=0, satisfying Equation 1 above. Furthermore, |(B2-LC / 2)| / LC=0, satisfying Equation 2 above. Furthermore, |(B1+B2-LC) / LC|=0, satisfying Equations 3 and 4 above. Therefore, the same effects as in Embodiments 1 and 2 described above can be obtained.

[0153] The preferred header configuration will be further described below based on other embodiments.

[0154] <Example 4>

[0155] Figure 10This is a schematic top view of a carriage 3D with the head configuration according to Embodiment 4. Embodiment 4 differs from Embodiment 1 in that the number of individual ink heads is increased. Specifically, the ink head 4 is identical to Embodiment 1 in that it includes the first to sixth ink heads 4A to 4F, each ejecting six different colors of ink; however, each ink head 4A to 4F of each color has three (a total of 18) individual ink heads. In other words, the ink head 4 has three (an odd number of) ink head rows, including a first ink head row 41, a second ink head row 42, and a third ink head row 43. The pre-processing head 5, positioned upstream of the ink head 4 in the transport direction F, includes two individual ink heads, and the post-processing head 6, positioned downstream, includes three individual ink heads. Furthermore, the positions of the pre-processing head 5 and the post-processing head 6 within the configuration width of the ink head 4 in the main scanning direction S are identical to those in Embodiment 1.

[0156] The first printhead 4A includes an upstream side head 4AA, a central head 4AB, and a downstream side head 4AC as unit heads. The upstream side head 4AA is positioned at the upstreammost side of the carriage 3A in the transport direction F of the first printhead 4A. The downstream side head 4AC is positioned downstream of the upstream side head 4AA at the same position as the upstream side head 4AA in the main scanning direction S. The central head 4AB is positioned offset to the right relative to the upstream side head 4AA and the downstream side head 4AC in the main scanning direction S, and is located downstream of the upstream side head 4AA and upstream of the downstream side head 4AC in the transport direction F. The central head 4AB is positioned to partially overlap with both the upstream side head 4AA and the downstream side head 4AC in the transport direction F.

[0157] The second to sixth printheads 4B to 4F also include the same upstream side heads 4BA, 4CA, 4DA, 4EA, 4FA, central heads 4BB, 4CB, 4DB, 4EB, 4FB, and downstream side heads 4BC, 4CC, 4DC, 4EC, and 4FC as the upstream side heads 4AA, central heads 4AB, and downstream side heads 4AC mentioned above. The upstream side heads 4AA to 4FA, central heads 4BB to 4FB, and downstream side heads 4BC to 4FC of the first to sixth printheads 4A to 4F are arranged in a row at predetermined intervals along the main scanning direction S at the same positions in the transport direction F. Furthermore, the printheads 4 are centrally arranged in the main scanning direction according to each color.

[0158] The preprocessing head 5 includes a first preprocessing head 5A and a second preprocessing head 5B arranged at the same position in the transport direction F and spaced apart in the main scanning direction S. The first preprocessing head 5A is configured such that a portion of its downstream side enters between the upstream head 4CA of the third printhead 4C and the upstream head 4DA of the fourth printhead 4D. The second preprocessing head 5B is configured such that a portion of its downstream side enters between the upstream head 4DA of the fourth printhead 4D and the upstream head 4EA of the fifth printhead 4E.

[0159] The post-processing head 6 includes a first post-processing head 6A, a second post-processing head 6B, and a third post-processing head 6C arranged at the same position in the transport direction F and spaced apart in the main scanning direction S. The first post-processing head 6A is configured such that a portion of its upstream side enters between the downstream head 4BC of the second printhead 4B and the downstream head 4CC of the third printhead 4C. The second post-processing head 6B is configured such that a portion of its upstream side enters between the downstream head 4CC of the third printhead 4C and the downstream head 4DC of the fourth printhead 4D. The third post-processing head 6C is configured such that a portion of its upstream side enters between the downstream head 4DC of the fourth printhead 4D and the downstream head 4EC of the fifth printhead 4E.

[0160] exist Figure 10 In the printhead configuration, the upstream side head 4AA or the downstream side head 4AC of the first printhead 4A is used as one end head, with LC=11, B1=5, 7, and B2=3, 5, 7. In this case, |(B1-LC / 2)| / LC=0.045, 0.136, both satisfying Equation 1 above. Furthermore, |(B2-LC / 2)| / LC=0.227, 0.045, 0.136, all satisfying Equation 2 above. Moreover, when B1=5, for each value of B2, |(B1+B2-LC) / LC|=0.273, 0.091, 0.091, all satisfying Equations 3 and 4 above. Furthermore, when B1=7, for each value of B2, |(B1+B2-LC) / LC|=0.091, 0.091, 0.272, all satisfying Equations 3 and 4 above. Therefore, the same effects as those in Examples 1 and 2 described above can be obtained.

[0161] Furthermore, the head configuration according to Embodiment 4 provides the same advantages as Embodiment 1. That is, it achieves both miniaturization of the carriage 3D and an increase in the necessary ink and processing fluid ejection volume. In particular, in Embodiment 4, both the pre-processing head 5 and the post-processing head 6 have a structure with multiple unit heads, thus significantly increasing the ejection volume of pre-processing fluid and post-processing fluid. Since the first to sixth inkheads 4A to 4F also have unit heads arranged in three rows, the ink ejection volume can also be significantly increased.

[0162] <Example 5>

[0163] Figure 11 This is a top view schematically showing the carriage 3E having the head configuration involved in Embodiment 5. In Embodiment 5, compared with Embodiment 1 ( Figure 6 Similarly, an example is shown where the pre-processing head 5 and the post-processing head 6 are configured in the central region HC of the configuration width H. However, as will be described later, Embodiment 5 differs from Embodiment 1 in the configuration of the printhead 4.

[0164] The head support frame 31 of the carriage 3E is equipped with first to sixth inkheads 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 inkheads 4A to 4F have the same two-row arrangement as in Embodiment 1. However, in the first inkhead 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 inkhead 4A to 4F is opposite to that in Embodiment 1. There is one pre-processing head 5, and two post-processing heads 6: a first post-processing head 6A and a second post-processing head 6B.

[0165] The pre-processing head 5 and the post-processing head 6 are disposed in the central region HC of the arrangement width H of the first to sixth printheads 4A to 4F in the main scanning direction S. The pre-processing head 5 is disposed upstream of the arrangement of the first to sixth printheads 4A to 4F in the transport direction F, and the post-processing head 6 is disposed downstream at the same point as in Embodiment 1 described above. The pre-processing head 5 is disposed at the same position as the downstream head 4C2 of the third printhead 4C in the main scanning direction S and upstream in the transport direction F. The pre-processing head 5 is disposed such that a portion of its downstream side enters between the upstream heads 4C1 and 4D1 of the third and fourth printheads 4C and 4D.

[0166] The first and second post-processing heads 6A and 6B are arranged at the same positions in the transport direction F and spaced apart at a predetermined interval in the main scanning direction S. The first post-processing head 6A is configured such that its upstream portion enters between the downstream side head 4B2 of the second printhead 4B and the downstream side head 4C2 of the third printhead 4C. The second post-processing head 6B is configured such that its upstream portion enters between the downstream side head 4C2 and the downstream side head 4D2 of the fourth printhead 4D.

[0167] In this head configuration of Embodiment 5, the distance LC from the upstream side head 4A1 of the first printhead 4A to the downstream side head of the sixth printhead 4F in the main scanning direction S is 11, the distance B1 from the upstream side head 4A1 to the pre-processing head 5 in the main scanning direction S is 5, and the distance B2 from the upstream side head 4A1 to each post-processing head 6 in the main scanning direction S is 4 or 6. At this time, |(B1-LC / 2)| / LC = 0.045, satisfying Equation 1 above. In addition, |(B2-LC / 2)| / LC = 0.136 or 0.045, both satisfying Equation 2 above. Therefore, the time difference from the landing of the pre-processing liquid to the landing of the ink ejected from the first printhead row 41, and the time difference from the landing of the ink ejected from the second printhead row 42 to the landing of the post-processing liquid can be reduced respectively. As a result, the pretreatment liquid, ink, and posttreatment liquid can be stably and sequentially deposited onto the workpiece W, making it difficult for differences in image quality to occur on the workpiece W. Furthermore, |(B1+B2-LC) / LC| = 0.18 or 0, both satisfying equations 3 and 4 above. Therefore, when multiple printhead rows containing printheads that eject ink of the same color are mounted on the carriage 3, for ink of a specified color, it is possible to suppress large time differences from the deposition of the pretreatment liquid to the first ink deposition and large time differences from the second ink deposition to the deposition of the posttreatment liquid.

[0168] Furthermore, the preprocessing head 5 and the postprocessing head 6 are not only disposed in the central region HC of the configuration width H, but are also configured in such a way that the configuration center of the preprocessing head 5 and the arrangement center of the first and second postprocessing heads 6A and 6B are aligned in the main scanning direction S. In this embodiment, since there is only one preprocessing head 5, the center of the preprocessing head 5 in the main scanning direction S is designated as the configuration center C1. As for the postprocessing head 6, the midpoint between the first postprocessing head 6A and the second postprocessing head 6B is designated as the arrangement center C2. The preprocessing head 5 and the postprocessing head 6 are configured on the head support frame 31 such that their configuration center C1 and arrangement center C2 are located at the same position in the main scanning direction S.

[0169] Based on Figure 4 As explained, in this embodiment, the carriage 3 repeatedly performs outgoing main scan and return main scan, causing the pretreatment liquid, ink, and posttreatment liquid to fall onto the workpiece W sequentially. By employing the head configuration of Embodiment 5 with such bidirectional main scan, the differences in time from the falling of the pretreatment liquid onto the workpiece W to the falling of the ink, as well as the differences in time from the falling of the ink to the falling of the posttreatment liquid, can be reduced in particular at each main scan position.

[0170] At this point, the preferred central region HC is a region located in the center of the configuration width H and with a width half of the configuration width H, more preferably one-third of the region. "The processing head is configured in the central region HC" means that the arrangement center of the processing head is configured in the central region HC, and more than half of the configuration centers of the processing head are configured in the central region HC. Alternatively, all configuration centers of the processing head may be configured in the central region HC.

[0171] <Example 6>

[0172] In Examples 6 and 7, head configurations that take measures to reduce the heat generation of processing heads 5 and 6 are illustrated. Typically, heads that eject liquid by jetting generate heat because they use electricity to pressurize the liquid. Inkhead 4 only ejects liquid when a desired color dot is formed. In contrast, pre-processing head 5 and post-processing head 6 need to eject pre-processing liquid and post-processing liquid corresponding to dots of all colors. Therefore, pre-processing head 5 and post-processing head 6 are more prone to overheating compared to inkhead 4. Therefore, it is preferable to configure the head configuration to accommodate the overheating of pre-processing head 5 and post-processing head 6.

[0173] Figure 12 This is a schematic top view of the carriage 3F having the head configuration according to Embodiment 6. The rear frame 32 (engaging part) of the carriage 3F is cantilevered by the guide rail 17 (holding member). Figure 1 The printhead support frame 31 is equipped with printheads 4 having first to sixth printheads 4A to 4F, a pre-processing head 5, and a post-processing head 6 having first and second post-processing heads 6A and 6B. These heads are configured in accordance with... Figure 6 The same as in Example 1 is shown, so the description is omitted here.

[0174] In this head configuration of Embodiment 6, LC=11, B1=6, and B2=5, 7. At this time, |(B1-LC / 2)| / LC=0.045, satisfying Equation 1 above. Furthermore, |(B2-LC / 2)| / LC=0.045 or 0.136, both satisfying Equation 2 above. Furthermore, |(B1+B2-LC) / LC|=0 or 0.18, both satisfying Equations 3 and 4 above.

[0175] Furthermore, in this embodiment, the pre-processing head 5 consists of a single unit head, and the post-processing head 6 consists of two unit heads (first and second post-processing heads 6A and 6B). The pre-processing head 5, with fewer unit heads, is positioned on the base end side 311 of the head support frame 31. The post-processing head 6, with more unit heads, is positioned on the distal end side 312. In other words, the upstream edge of the head support frame 31 in the conveying direction F is the side held by the guide rail 17.

[0176] As mentioned above, processing heads 5 and 6 generate heat due to the ejection action. Figure 12 As illustrated in the diagram, the pre-processing head 5, heated to a high temperature, releases heat ha. The same applies to the first and second post-processing heads 6A and 6B. This heat ha causes the head support frame 31 of the carriage 3F to heat up, potentially leading to thermal deformation of the head support frame 31, its retaining structure, the rear frame 32, and the fasteners connecting the rear frame 32 and the timing belt 16. This thermal deformation, within the cantilevered carriage 3F, may affect the accuracy of ink delivery from the printhead 4.

[0177] However, in the carriage 3F of embodiment 6, a pre-processing head 5 with a smaller number of unit heads is arranged on the cantilevered side 311 of the head support frame 31. This reduces the impact of thermal deformation (reduced landing accuracy). If a post-processing head 6 with a larger number of unit heads is arranged on the base end side 311, the rear frame 32 is subjected to heat released from the two unit heads, resulting in higher temperatures and a greater susceptibility to thermal deformation.

[0178] Furthermore, in the carriage 3F of embodiment 6, the preprocessing head 5 is positioned in the head arrangement body HA (head placement area) of the printhead 4 and the processing heads 5 and 6, except for the end in the main scanning direction S. Among the heads 4, 5, and 6 mounted on the carriage 3F, the preprocessing head 5, as a processing head, is positioned on the side closest to the rear frame 32 (engaging portion). This preprocessing head 5 is positioned in a position other than the end of the head arrangement body HA, i.e., the placement end 313.

[0179] Since the carriage 3F cannot be unnecessarily enlarged, if the head is positioned at the configuration end 313 in the main scanning direction S of the head array, this head becomes the corner head closest to the carriage 3F (head support frame 31) in the main scanning direction S. Since the area near the configuration end 313 is also near the cantilevered rear frame 32, thermal deformation in this area could potentially cause deformation or positional shift of the head support frame 31 in the vertical or horizontal direction. This reduces the landing position accuracy of the heads 4, 5, and 6 mounted on the carriage 3F. Therefore, by not configuring the high-temperature processing heads (pre-processing head 5 and post-processing head 6) in the area of ​​the configuration end 313, the aforementioned thermal deformation problem can be prevented from occurring.

[0180] In this embodiment, the column of printheads 4 arranged on the engaging side in one of the two columns (first printhead column 41, second printhead column 42) is used. Figure 12 The serrated arrangement is offset to the right. Furthermore, the pre-processing head 5, which has fewer heads, is positioned on the engaging side, and is located in the center of the serrated arrangement. This arrangement allows the heads to be configured such that the processing head is not positioned on the mounting end 313.

[0181] Reference Figure 12 The head configuration of the carriage 3F shown further illustrates a preferred printhead configuration example. In the carriage 3F, the high-temperature pre-processing head 5 is configured such that a portion of it is adjacent to the printhead 4. Specifically, the pre-processing head 5 is adjacent to the upstream heads 4C1 and 4D1 of the third and fourth printheads 4C and 4D in the main scanning direction S, and to the downstream head 4D2 of the fourth printhead 4D in the transport direction F. Furthermore, the first post-processing head 6A is adjacent to the downstream heads 4C2 and 4D2 of the third and fourth printheads 4C and 4D in the main scanning direction S, and to the upstream head 4C1 in the transport direction F. The second post-processing head 6B is adjacent to the downstream heads 4D2 and 4E2 of the fourth and fifth printheads 4D and 4E in the main scanning direction S, and to the upstream head 4D1 in the transport 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 printheads 4A, 4B, and 4F.

[0182] In the above-described printhead configuration, for example, the third, fourth, and fifth printheads 4C, 4D, and 4E (the first printheads that spray the first color ink), which spray yellow, red, and blue ink respectively, have more adjacent printheads to the pre-processing head 5 and the post-processing head 6 compared to the first, second, and sixth printheads 4A, 4B, and 4F (the second printheads that spray the second color ink), which spray orange, green, and black ink respectively. That is, the third, fourth, and fifth printheads 4C, 4D, and 4E are printheads that are more easily heated to high temperatures than the other printheads 4A, 4B, and 4F.

[0183] If the viscosity of the ink changes significantly with temperature, the ink ejection characteristics (ejection volume, etc.) from the printhead will also change. The viscosity change characteristics due to temperature vary depending on the type of ink. Therefore, in this embodiment, the ink ejected from the third, fourth, and fifth printheads 4C, 4D, and 4E, which are prone to high temperatures, exhibits a smaller viscosity change due to temperature compared to the ink ejected from the first, second, and sixth printheads 4A, 4B, and 4F. Accordingly, even if the third, fourth, and fifth printheads 4C, 4D, and 4E are heated by the pre-processing head 5 and the post-processing head 6, the temperature-induced changes in the ejection volume and ejection speed of the ink ejected from these printheads 4C, 4D, and 4E can be reduced.

[0184] At this point, for each ink, the number of units in the processing heads adjacent to printhead 4 can also be used to evaluate the maximum number of units in adjacent processing heads of printhead 4 that ejects a certain ink. In the first, second, and sixth printheads 4A, 4B, and 4F, the maximum number of units in adjacent processing heads is 0. In the third printhead 4C, the maximum number of units in adjacent processing heads is 2. In the fourth printhead 4D, the maximum number of units in adjacent processing heads is 3. In the fifth printhead 4E, the maximum number of units in adjacent processing heads is 1.

[0185] Furthermore, for each ink, the number of processing heads per unit adjacent to printhead 4 can also be used to evaluate the average number of processing heads per unit among adjacent processing heads in printhead 4 that ejects a certain ink. In the first, second, and sixth printheads 4A, 4B, and 4F, the average number of processing heads per unit among adjacent processing heads is 0. In the third printhead 4C, the average number of processing heads per unit among adjacent processing heads is 1.5, and in the fourth printhead 4D, the average number of processing heads per unit among adjacent processing heads is 2.5. In the fifth printhead 4E, the average number of processing heads per unit among adjacent processing heads is 0.5.

[0186] As a combined evaluation, for example, the maximum number of units of adjacent processing heads can be evaluated first, and for inks in which there is no difference in this evaluation, the average number of units of adjacent processing heads can be evaluated.

[0187] In addition, the order in which the inkheads 4 that eject each ink are most likely to reach high temperatures can be evaluated, and inks with smaller viscosity temperature changes can be ejected in the order that are most likely to reach high temperatures.

[0188] <Example 7>

[0189] In Example 7, an embodiment is shown that considers a high-temperature countermeasure for the pre-processing head 5 and post-processing head 6 among multiple inkheads of the same color that eject ink. In the above embodiment, examples are shown where each of the first to sixth inkheads 4A to 4F of each color has two or three unit heads. If the difference in the number of unit heads adjacent to the pre-processing head 5 or post-processing head 6 is large, an undesirable situation occurs where the ink ejection characteristics are significantly different between these unit heads. In this embodiment, an example of a head configuration that reduces the difference in the number of adjacent unit heads is shown.

[0190] Figure 13 This is a top view schematically showing the carriage 3G having the head configuration according to Embodiment 7. The carriage 3G has a head configuration such that when counting the number of each of the two unit heads (same color ink heads) 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, the difference between the maximum and minimum values ​​of their count values ​​is less than 1.

[0191] The printhead 4 configuration in the carriage 3G is the same as described above. Figure 12 The carriage 3F shown has the same head configuration. On the other hand, the pre-processing head 5 includes a first and a second pre-processing head 5A and 5B arranged in the main scanning direction S, separated by an upstream side head 4C1 from the third printhead 4C. The post-processing head 6 includes a first and a second post-processing head 6A and 6B arranged in the main scanning direction S, separated by a downstream side head 4C2.

[0192] In this embodiment 7, the downstream side of the first printhead 4A is used as one end, with LC=11, B1=4, 6, and B2=3, 5. At this time, |(B1-LC / 2)| / LC = 0.136 and 0.045, satisfying Equation 1 above. Furthermore, |(B2-LC / 2)| / LC = 0.227 or 0.045, both satisfying Equation 2 above. Therefore, the time difference from the landing of the pretreatment liquid to the landing of the ink ejected from the first printhead row 41, and the time difference from the landing of the ink ejected from the second printhead row 42 to the landing of the posttreatment liquid, can be reduced respectively. As a result, the pretreatment liquid, ink, and posttreatment liquid can be stably and sequentially deposited on the workpiece W, making it difficult for image quality differences to occur on the workpiece W. Furthermore, when B1 = 4, |(B1 + B2 - LC) / LC| = 0.364 or 0.181, one of which does not satisfy equations 3 and 4 above, but the other does. Additionally, when B1 = 6, |(B1 + B2 - LC) / LC| = 0.181 or 0, both satisfying equations 3 and 4 above. Therefore, when multiple printheads, each ejecting ink of the same color, are mounted on the carriage 3, for ink of a specified color, it is possible to suppress large time differences from the arrival of the pretreatment liquid to the arrival of the first ink, and large time differences from the arrival of the second ink to the arrival of the posttreatment liquid.

[0193] In the second printhead 4B of the carriage 3G, the count values ​​of the processing heads 5 and 6 adjacent to the upstream side head 4B1 and the downstream side head 4B2 in the main scanning direction S and the transport direction F are 2 and 1 respectively, with a difference of "1". In the third printhead 4C, the count values ​​of the upstream side head 4C1 and the downstream side head 4C2 are both 3, with a difference of "0". In the fourth printhead 4D, the count value of the upstream side head 4D1 is 1, and the count value of the downstream side head 4D2 is 2, with a difference of "1". The count values ​​of the remaining printheads 4A, 4E, and 4F are all 0. Therefore, for all the first to sixth printheads 4A to 4F, the difference between the maximum and minimum values ​​is less than 1, satisfying the above requirements.

[0194] As described above, in Example 7, the difference between the maximum and minimum values ​​of the count values ​​of the upstream side heads 4A1 to 4F1 and the downstream side heads 4A2 to 4F2 of the first to sixth printheads 4A to 4F adjacent to the processing heads 5 and 6 is less than 1. Accordingly, it is possible to prevent large differences in ink ejection volume among multiple printheads of the same color.

[0195] <Example 8>

[0196] Figure 14This is a top view schematically showing the carriage 3H having the head configuration involved in Embodiment 8. Embodiment 8 shows an example where the pre-processing head 5 and the post-processing head 6 are not dispersed on the head support frame 31, but are arranged as centrally as possible, thereby reducing the contact between the pre-processing liquid and the post-processing liquid and the ink.

[0197] Example 8 illustrates a header configuration that satisfies the following requirements (A) to (C).

[0198] (A) When the number of units in the preprocessing header 5 and the postprocessing header 6 that has more units is set to m, and the number of units in the postprocessing header 6 that has fewer units is set to n, the condition that m = n + an odd number is satisfied.

[0199] (B) The configuration or arrangement center of one or more preprocessing heads 5 in the main scanning direction S coincides with the configuration or arrangement center of one or more postprocessing heads 6 in the main scanning direction S, and

[0200] (C) The configuration or arrangement center of the pre-processing head 5 and the post-processing head 6 is consistent with the configuration position of one of the printheads in the printhead 4 in the main scanning direction S.

[0201] Figure 8 The carriage 3H shown includes a printhead 4, a pre-processing head 5, and a post-processing head 6 with first and second post-processing heads 6A and 6B. The head configuration is... Figure 12 The same applies to the others. Therefore, the head configuration in Embodiment 8 also satisfies the relationships described in Equations 1 to 4, achieving the same effect. Furthermore, in this example, the number of post-processing heads 6 is m = 2, and the number of pre-processing heads 5 is n = 1. Therefore, m = n + an odd number satisfies the above 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 center C in the figure, also satisfying the above requirement (B). Moreover, center C coincides with the configuration position of the downstream head 4D2 of the fourth print head 4D, also satisfying the above requirement (C).

[0202] According to the head configuration of Embodiment 8, the pre-processing head 5 and the post-processing head 6 can be mounted on the carriage 3H in a somewhat concentrated manner. Accordingly, the number of printheads 4A to 4F located near the pre-processing head 5 or the post-processing head 6 can be reduced. Therefore, the possibility of pre-processing liquid and post-processing liquid coming into contact with ink on the carriage can be reduced.

[0203] <Example 9>

[0204] In Example 9, a preferred configuration relationship between the heads 4, 5, and 6 on the carriage and the auxiliary containers that supply ink or processing liquid to them is illustrated. Figure 15This is a top view showing the carriage 3I with the head configuration according to Embodiment 9 and the sub-container configuration. The carriage 3I includes printheads 4 having first to sixth printheads 4A to 4F, a pre-processing head 5, and a post-processing head 6 having first and second post-processing heads 6A and 6B. Their head configuration is similar to... Figure 12 The same applies to the others. Therefore, the head configuration in Embodiment 9 also satisfies the relationships described in Equations 1 to 4, and can achieve the same effect.

[0205] The carriage 3I also houses auxiliary containers 7. These auxiliary containers 7 include ink auxiliary containers 7A to 7F, a pretreatment liquid auxiliary container 71, and a post-treatment liquid auxiliary container 72 (all are processing liquid auxiliary containers). Ink, pretreatment liquid, and post-treatment liquid are supplied to these auxiliary containers 7 from the main container (not shown). The ink auxiliary containers 7A to 7F supply the ink to the first to sixth printheads 4A to 4F, respectively. For example, ink of the first color is supplied from the first container 7A1 of the ink auxiliary container 7A via conduit P1 to the upstream side 4A1 of the first printhead 4A, and from the second container 7A2 via conduit P1 to the downstream side 4A2. The second to sixth printheads 4B to 4F are similarly supplied with ink of the second to sixth colors, respectively.

[0206] The arrangement order of the ink sub-containers 7 in the main scanning direction S is the same as the arrangement order of the printheads 4 supplying ink to each ink sub-container 7 in the main scanning direction S. Alternatively, ink can be supplied from one ink sub-container 7 to multiple printheads 4 that eject ink of the same color. In this case, the printheads 4 sharing the ink sub-container 7 can be arranged in a concentrated position in the main scanning direction S. Furthermore, it is preferable to concentrate the printheads 4 ejecting the same ink in the main scanning direction S, and the arrangement order of the ink sub-containers 7 for each color in the main scanning direction S can also be the same as the arrangement order of the printheads 4 for each color.

[0207] The pretreatment solution auxiliary container 71 supplies pretreatment solution to the pretreatment head 5 via pipeline P2. The posttreatment solution auxiliary container 72 includes a first container 72A and a second container 72B. The first and second containers 72A and 72B supply posttreatment solution to the first and second posttreatment heads 6A and 6B via pipeline P3, respectively.

[0208] Ink auxiliary containers 7A to 7F are mounted on carriage 3I in an arrangement along the main scanning direction S. Processing liquid auxiliary containers 71 and 72 are positioned differently in the transport direction F from ink auxiliary containers 7A to 7F. Furthermore, processing liquid auxiliary containers 71 and 72 are arranged in the main scanning direction S. Specifically, the first and second containers 72A and 72B of the pre-processing liquid auxiliary container 71 and the post-processing liquid auxiliary container 72 are arranged in a row along the main scanning direction S downstream of the ink auxiliary containers 7A to 7F. Alternatively, only the pre-processing liquid auxiliary container 71 may be arranged upstream of the ink auxiliary containers 7A to 7F.

[0209] The liquid in the sub-container 7, mounted on a carriage 3I that reciprocates along the main scanning direction S, is subjected to acceleration in that direction. The sub-container 7 is connected to each of the heads 4, 5, and 6 via conduits P1, P2, and P3. However, if the sub-containers 7 are widely distributed on the carriage 3I, the configuration range of conduits P1 to P3 in the main scanning direction S also increases. Since these conduits P1 to P3 are also filled with ink or processing fluid, meniscus breakdown can sometimes occur at the ejection portions of heads 4, 5, and 6 under the influence of this acceleration.

[0210] However, according to the configuration of Embodiment 9, the ink sub-containers 7A to 7F, like the first to sixth printheads 4A to 4F, are mounted on the carriage 3I in a manner arranged along the main scanning direction S. Therefore, a relatively narrow range of ink sub-containers 7A to 7F can be arranged on the head support frame 31 of the carriage 3I. Similarly, the pretreatment liquid sub-container 71 and the posttreatment liquid sub-container 72 can also be arranged on a relatively narrow range of the head support frame 31 of the carriage 3I.

[0211] Furthermore, since the pretreatment liquid auxiliary container 71 and the posttreatment liquid auxiliary container 72 are positioned in the transport direction F differently from the ink auxiliary containers 7A to 7F, the positional difference in the main scanning direction S between the pretreatment liquid auxiliary container 71 and the posttreatment liquid auxiliary container 72 and the processing head supplying the processing liquid to each of the pretreatment liquid auxiliary container 71 and the posttreatment liquid auxiliary container 72 is minimized. Accordingly, the distribution range of the pretreatment liquid connected in the pretreatment liquid auxiliary container 71, the pipeline P, and the pretreatment head 5 in the main scanning direction S can be reduced, making it less susceptible to the effects of acceleration. Similarly, the distribution range of the connected posttreatment liquid in the main scanning direction S can be reduced, making it less susceptible to the effects of acceleration.

[0212] Similarly, it is possible to configure the ink sub-containers 7A to 7F and the printheads 4 supplying ink to each ink sub-container 7A to 7F to minimize the positional difference in the main scanning direction S. Accordingly, the distribution range of adjacent ink in the main scanning direction S can be reduced, making it less susceptible to the effects of acceleration.

[0213] <Example 10>

[0214] also, Figure 16 This is a top view of the carriage 3J showing the head configuration according to Embodiment 10. In Embodiment 10, the printhead 4 has a first printhead row 41 and a second printhead row 42. In this embodiment, the post-processing head 6 is located approximately at the center of the arrangement of all heads in the main scanning direction S, while the pre-processing head 5 is located at one end of the arrangement (in... Figure 16(The middle part is the left end). At this time, the downstream side head of the first print head 4A and the pre-processing head 5 are equivalent to one end side head.

[0215] In this head configuration, LC=11, B1=0, and B2=5. At this time, |(B1-LC / 2)| / LC=0.5, which does not satisfy Equation 1 above. On the other hand, |(B2-LC / 2)| / LC=0.045, which satisfies Equation 2 above. This head configuration is suitable for situations where the pretreatment fluid function has sufficient leeway to accommodate the time difference between the arrival of the pretreatment fluid and the arrival of the ink ejected from the first printhead row 41, but the time difference between the arrival of the ink ejected from the second printhead row 42 and the arrival of the posttreatment fluid should be reduced.

[0216] <Example 11>

[0217] also, Figure 17 This is a top view of the carriage 3K showing the head configuration according to Embodiment 11. In Embodiment 11, the printhead 4 has a first printhead row 41 and a second printhead row 42. In this embodiment, the post-processing head 6 is located approximately at the center of the arrangement of all heads in the main scanning direction S, while the pre-processing head 5 is located at the other end of the arrangement (in... Figure 17 (The middle part is the right end). At this time, the downstream side of the first print head 4A is equivalent to one end of the side head.

[0218] In this head configuration, LC=11, B1=10, and B2=5. At this time, |(B1-LC / 2)| / LC=0.409, which does not satisfy Equation 1 above. On the other hand, |(B2-LC / 2)| / LC=0.045, which satisfies Equation 2 above. This head configuration, similar to Embodiment 10, is suitable for situations where the pretreatment liquid function has sufficient leeway to accommodate the time difference between the arrival of the pretreatment liquid and the arrival of the ink ejected from the first printhead row 41, but the time difference between the arrival of the ink ejected from the second printhead row 42 and the arrival of the posttreatment liquid should be reduced.

[0219] Alternatively, the configuration of the pre-processing head 5 may be the opposite of embodiments 10 and 11 described above, where the configuration satisfies Equation 1, while the configuration of the post-processing head 6 does not satisfy Equation 2. In this case, it is suitable to have sufficient capacity to accommodate the time difference between the landing of ink ejected from the second printhead column 42 and the landing of the post-processing liquid, but the time difference between the landing of the pre-processing liquid and the landing of ink ejected from the first printhead column 41 should be reduced.

[0220] <About Inkjet Recording Methods>

[0221] As described above, the inkjet printer 1 in each embodiment has one printhead array mounted at a predetermined position on the carriage 3 in the transport direction F, or multiple printhead arrays, a pre-processing head, and a post-processing head mounted on the carriage 3 in an arrangement in the transport direction F. Each of the one or more printhead arrays includes multiple printheads arranged in the main scanning direction S and ejecting ink for image formation. The pre-processing head 5 is disposed upstream of the one or more printhead arrays in the transport direction F and ejects a non-coloring pre-processing liquid. The post-processing head 6 is disposed downstream of the one or more printhead arrays in the transport direction F and ejects a non-coloring post-processing liquid.

[0222] Furthermore, one inkjet recording method in the aforementioned inkjet printer 1 includes: When a plurality of printheads 4 and processing heads (pre-processing head 5 and post-processing head 6) are configured such that the head closest to one end in the main scanning direction S is a one-end head, and the head closest to the other end is a other-end head, the distance from the one-end head to the other-end head in the main scanning direction S is LC, and the distance from the one-end head to the pre-processing head 5 in the main scanning direction S is B1, the pre-processing head 5 is configured such that |(B1-LC / 2)| / LC≤1 / 4 (Equation 1); while moving the carriage 3 in the main scanning direction S, pre-processing liquid is ejected from the pre-processing head 5 onto a predetermined recording area on the workpiece W; while conveying the workpiece W along the transport direction F at a predetermined transport interval and moving the carriage 3 along the main scanning direction S, ink is ejected from the printheads 4 onto the recording area that has been sprayed with pre-processing liquid.

[0223] According to this method, an inkjet printer 1, in which the pretreatment liquid and ink ejection heads are mounted on a carriage 3, can effectively form an image on a workpiece W. Furthermore, since the pretreatment head 5 and the print head 4 are sequentially arranged in the transport direction F, the pretreatment liquid and ink can be ejected onto the recording medium in a desired landing sequence. Moreover, by appropriately configuring the pretreatment head 5 in accordance with Equation 1, the time difference from the landing of the pretreatment liquid to the landing of the ink can be reduced. As a result, differences in image quality on the workpiece W are less likely to occur.

[0224] Furthermore, in the method described above, the processing head mounted on the carriage 3 may simply be the pre-processing head 5. Additionally, in the method described above, recording may end without applying the post-processing liquid, or the post-processing liquid may be applied after printing has finished on the carriage 3. In the latter case, the post-processing liquid is applied to approximately the entire surface of the workpiece W, for example, by spraying, transferring using rollers, or immersion in the post-processing liquid.

[0225] Furthermore, another inkjet recording method in the inkjet printer 1 described above includes: configuring the post-processing head 6 in a manner that satisfies the relationship |(B2-LC / 2)| / LC≤1 / 4 (Equation 2); while moving the carriage 3 in the main scanning direction S, ink is ejected from the printhead 4 to a predetermined recording area on the workpiece W; while conveying the workpiece W along the transport direction F at the transport interval and moving the carriage 3 along the main scanning direction S, post-processing liquid is ejected from the post-processing head 6 to the recording area that has been sprayed with ink.

[0226] In this method, an inkjet printer 1, with ink and post-processing liquid ejection heads mounted on a carriage, can effectively form an image on a workpiece W. Furthermore, since the printhead 4 and post-processing head 6 are sequentially arranged in the transport direction, the ink and post-processing liquid can be ejected onto the workpiece W in a desired landing sequence. Moreover, by appropriately configuring the post-processing head 6 according to Equation 2, the time difference from ink landing to post-processing liquid landing can be reduced. As a result, differences in image quality on the workpiece W are less likely to occur.

[0227] Furthermore, in the above method, the processing head mounted on the carriage 3 can also be only the post-processing head 6. Additionally, in the above method, recording can be completed without applying the pretreatment liquid, or the pretreatment liquid can be applied before printing using the carriage 3. In the latter case, the pretreatment liquid is applied to approximately the entire surface of the workpiece W, for example, by spraying, transferring using a roller, or immersion in the pretreatment liquid.

[0228] Furthermore, another inkjet recording method in the inkjet printer 1 described above includes: arranging the pre-processing head 5 and the post-processing head 6 on the carriage 3 in a manner satisfying Formulas 1 and 2; while moving the carriage 3 in the main scanning direction S, ejecting pre-processing liquid from the pre-processing head 5 onto a predetermined recording area on the workpiece W; while conveying the workpiece W along the transport direction F at a predetermined transport interval and moving the carriage 3 along the main scanning direction S, ejecting ink from the printhead 4 onto the recording area that has been sprayed with pre-processing liquid; ejecting ink from the printhead 4 onto the recording area that has been sprayed with pre-processing liquid; while further conveying the workpiece W along the transport direction F at the transport interval and moving the carriage 3 along the main scanning direction S, ejecting post-processing liquid from the post-processing head 6 onto the recording area that has been sprayed with ink.

[0229] According to this method, a multi-functional inkjet printer 1, which mounts the pretreatment liquid, ink, and posttreatment liquid ejection heads on a carriage 3, can effectively form an image on the workpiece W. Furthermore, since the pretreatment head 5, ink head 4, and posttreatment head 6 are sequentially arranged in the transport direction F, the pretreatment liquid, ink, and posttreatment liquid can be ejected onto the recording medium in a desired landing order. Moreover, by appropriately arranging the pretreatment head 5 and posttreatment head 6 in accordance with Equations 1 and 2, the time difference from the landing of the pretreatment liquid to the landing of the ink, and the time difference from the landing of the ink to the landing of the posttreatment liquid, can be reduced. As a result, differences in image quality on the workpiece W are less likely to occur.

[0230] <Regarding the comparative examples>

[0231] Figure 18 This is a top view of the carriage 3Z1 with the head configuration involved in Comparative Example 1, which is compared with the present invention. In this head configuration of Comparative Example 1, LC=13, B1=0, and B2=13. In this case, |(B1-LC / 2)| / LC=0.409, which does not satisfy Equation 1 above. Furthermore, |(B2-LC / 2)| / LC=0.682, which does not satisfy Equation 2 above.

[0232] same, Figure 19 This is a top view of the carriage 3Z2 with the head configuration involved in Comparative Example 2, which is compared with the present invention. In this head configuration of Comparative Example 2, LC=7, B1=0, and B2=7. In this case, |(B1-LC / 2)| / LC=0.5, which does not satisfy Equation 1 above. Furthermore, |(B2-LC / 2)| / LC=0.5, which does not satisfy Equation 2 above.

[0233] In the head configurations of Comparative Examples 1 and 2, the time difference between the arrival of the pretreatment liquid and the arrival of the ink ejected from the first ink head column 41 is greater, and the time difference between the arrival of the ink ejected from the second ink head column 42 and the arrival of the posttreatment liquid is also greater. Therefore, the image formed on the workpiece W is also prone to differences.

[0234] [Summary of the Invention]

[0235] One aspect of the present invention relates to an inkjet recording apparatus comprising a transport unit, a carriage, one or more printhead arrays, and a processing head. The transport unit transports a recording medium along a predetermined transport direction. The carriage reciprocates along a main scanning direction intersecting the transport direction. The one or more printhead arrays are mounted on the carriage at predetermined positions along the transport direction. The processing head is mounted on the carriage for ejecting a non-coloring processing liquid. Each of the one or more printhead arrays includes multiple printheads arranged in a manner along the main scanning direction for ejecting ink for image formation. The processing head includes a pre-processing head positioned upstream of the one or more printhead arrays along the transport direction for ejecting a pre-processing liquid, which is the processing liquid. In the case that among the plurality of printheads and the processing head, the head closest to one end in the main scanning direction is designated as the one-end head, the head closest to the other end is designated as the other-end head, the distance from the one-end head to the other end head in the main scanning direction is LC, and the distance from the one-end head to the pre-processing head in the main scanning direction is B1, the pre-processing head is configured in a manner that satisfies the relationship of Equation 1.

[0236] |(B1-LC / 2)| / LC≤1 / 4 (Equation 1)

[0237] According to this configuration, an inkjet recording apparatus can be provided in which a pretreatment liquid and an ink ejection head are mounted on a carriage. Furthermore, since the pretreatment head and the ink head are sequentially arranged in the transport direction, the pretreatment liquid and ink can be ejected onto the recording medium in a desired landing sequence. Moreover, by appropriately arranging the pretreatment head in accordance with Formula 1, the time difference from the landing of the pretreatment liquid to the landing of the ink can be reduced regardless of the carriage's direction of movement. As a result, the pretreatment liquid and ink land sequentially on the recording medium, thereby minimizing image quality variations on the recording medium.

[0238] In the above configuration, it is also possible that: multiple preprocessing heads are arranged in the main scanning direction, and at least one of the multiple preprocessing heads is configured in a manner that satisfies the relationship in Equation 1.

[0239] According to this configuration, even when multiple pretreatment heads are configured, by configuring at least one of the pretreatment heads to satisfy Equation 1, the time difference from the arrival of the pretreatment liquid to the arrival of the ink can be reduced. Furthermore, since pretreatment liquid can also be ejected from other pretreatment heads, the amount of pretreatment liquid that can be ejected can be increased.

[0240] In the above configuration, the plurality of preprocessing heads can also be configured such that they all satisfy the relationship in Equation 1.

[0241] According to this configuration, multiple pretreatment heads are configured in a manner that satisfies Formula 1, thereby further reducing the time difference from the arrival of the pretreatment liquid to the arrival of the ink, and increasing the amount of treatment liquid that can be ejected.

[0242] In the above configuration, the pre-processing head may also include a post-processing head disposed downstream of the one or more printhead columns in the transport direction for ejecting a post-ejection liquid as the processing liquid. The printhead columns are arranged in multiple columns along the transport direction. One of the printhead columns has a printhead for ejecting ink of a specified color. Other printhead columns in the multiple printhead columns have other printheads disposed adjacent to the printhead and ejecting ink of the specified color. When the distance from one end 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 following relationship.

[0243] |(B1+B2-LC) / LC|≤1 / 2.

[0244] According to this configuration, a multi-functional integrated inkjet recording device can be provided, which mounts the pretreatment head, ink, and post-treatment head onto a single carriage. Furthermore, since the pretreatment head, ink head, and post-treatment head are sequentially arranged in the transport direction, the pretreatment head, ink, and post-treatment head can be ejected onto the recording medium in a desired landing order. Moreover, in a configuration where multiple ink head rows eject ink of the same color to a predetermined ejection target area, it is possible to prevent both the time difference from the landing of the pretreatment head to the landing of ink ejected from the upstream ink head in the transport direction and the time difference from the landing of ink ejected from the downstream ink head in the transport direction to the landing of the post-treatment head from the downstream ink head in the transport direction from becoming large.

[0245] Furthermore, another aspect of the present invention relates to an inkjet recording apparatus comprising a transport unit, a carriage, one or more printhead arrays, and a processing head. The transport unit transports a recording medium along a predetermined transport direction. The carriage reciprocates along a main scanning direction intersecting the transport direction. The one or more printhead arrays are mounted on the carriage at predetermined positions along the transport direction. The processing head is mounted on the carriage for ejecting a non-coloring processing liquid. Each of the one or more printhead arrays includes multiple printheads arranged in a manner along the main scanning direction for ejecting ink for image formation. The processing head includes a post-processing head disposed downstream of the one or more printhead arrays along the transport direction for ejecting a post-processing liquid, which is the processing liquid. In the case that among the plurality of printheads and the processing head, the head closest to one end in the main scanning direction is designated as the one-end head, the head closest to the other end is designated as the other-end head, the distance from the one-end head to the other end head in the main scanning direction is LC, and the distance from the one-end head to the post-processing head in the main scanning direction is B2, the post-processing head is configured in a manner that satisfies the relationship of Equation 2.

[0246] |(B2-LC / 2)| / LC≤1 / 4 (Equation 2)

[0247] According to this configuration, an inkjet recording apparatus can be provided in which the ink and post-processing liquid ejection heads are mounted on a carriage. Furthermore, since the ink head and post-processing head are sequentially arranged in the transport direction, the ink and post-processing liquid can be ejected onto the recording medium in a desired landing sequence. Moreover, by appropriately arranging the post-processing head according to Equation 2, the time difference from ink landing to post-processing liquid landing can be reduced regardless of the carriage's direction of movement. As a result, differences in image quality on the recording medium are less likely to occur.

[0248] In the above configuration, it is also possible that multiple post-processing heads are arranged in the main scanning direction, and at least one of the multiple post-processing heads is configured in a manner that satisfies the relationship in Equation 2.

[0249] According to this configuration, even when multiple post-processing heads are configured, by configuring at least one of the post-processing heads to satisfy Equation 2, the time difference from ink drop to post-processing liquid drop can be reduced. Furthermore, since post-processing liquid can also be ejected from other post-processing heads, the amount of post-processing liquid that can be ejected can be increased.

[0250] In the above configuration, the multiple post-processing heads can also be configured such that they all satisfy the relationship in Equation 2.

[0251] According to this configuration, multiple post-processing heads are configured in a manner that satisfies Equation 2, thereby further reducing the time difference from ink drop to post-processing liquid drop and increasing the amount of sprayable processing liquid.

[0252] In the above configuration, the processing head may also include a pre-processing head configured in the transport direction upstream of the one or more printhead columns for ejecting a pre-ejection liquid as the processing liquid. The printhead columns are arranged in multiple columns along the transport direction. One of the printhead columns has a printhead that ejects ink of a specified color. Other printhead columns in the multiple printhead columns have other printheads that are arranged adjacent to the printhead and eject ink of the specified color. When the distance from one end head to the pre-processing head in the main scanning direction is B1, the pre-processing head and the post-processing head are configured in a manner that satisfies the following relationship.

[0253] |(B1+B2-LC) / LC|≤1 / 2

[0254] According to this configuration, in a configuration that ejects ink of the same color from multiple printhead rows to a specified ejection target area, it is possible to suppress the increasing time difference between the arrival of pretreatment liquid and the arrival of ink ejected from the upstream printhead in the transport direction, as well as the increasing time difference between the arrival of ink ejected from the downstream printhead in the transport direction and the arrival of posttreatment liquid.

[0255] In the above configuration, the processing head may also include a pre-processing head configured to eject a pre-ejection liquid, which is positioned upstream of the one or more printhead rows in the transport direction. When the distance from one end head to the pre-processing head in the main scanning direction is B1, the pre-processing head is configured to satisfy the following relationship: |(B1-LC / 2)| / LC≤1 / 4

[0256] According to this configuration, by appropriately configuring the pretreatment head in a manner that satisfies the above formula, it is possible to further reduce the time difference from the application of the pretreatment liquid to the application of the ink.

[0257] In the above configuration, it can also be that: multiple rows of printheads are arranged in a manner that follows the transport direction; one printhead row in the multiple printhead rows has a printhead for ejecting ink of a specified color; other printhead rows in the multiple printhead rows have other printheads arranged adjacent to the printhead and ejecting ink of the specified color; and the pre-processing head and the post-processing head are configured in a manner that satisfies the following relationship: |(B1+B2-LC) / LC|≤1 / 3

[0258] According to this configuration, in a configuration that ejects ink of the same color from multiple printhead rows to a specified ejection target area, it is possible to suppress the increasing time difference between the arrival of pretreatment liquid and the arrival of ink ejected from the upstream printhead in the transport direction, as well as the increasing time difference between the arrival of ink ejected from the downstream printhead in the transport direction and the arrival of posttreatment liquid.

[0259] In the above configuration, the processing head can also be configured within the range of the configuration width of the plurality of printheads in the main scanning direction.

[0260] According to this inkjet recording device, even when the processing head is mounted on the carriage, it is not necessary to increase the width of the carriage in the main scanning direction. Therefore, it is possible to miniaturize the width of the carriage in the main scanning direction.

[0261] In the above configuration, the processing head may also be configured such that a portion of it enters between a pair of printheads, the pair of printheads being a pair of printheads adjacent to each other in the main scanning direction among the plurality of printheads included in a printhead column.

[0262] According to this inkjet recording device, printheads and processing heads arranged at different positions in the transport direction (sub-scanning direction) can be arranged with high density along the transport direction. Therefore, it is possible to miniaturize the width of the carriage in the transport direction.

[0263] In the above configuration, the processing head may also be configured such that a portion of it is adjacent to the printhead in the main scanning direction and the transport direction, the plurality of printheads including a plurality of same-color printheads that eject ink of the same color, and when counting the number of processing heads adjacent to each of the same-color printheads in the processing head in the main scanning direction and the transport direction, the difference between the maximum and minimum values ​​of their counts is less than 1.

[0264] Typically, inkjet printheads that eject liquids via a jetting method generate heat because they use electricity to pressurize the liquid. In particular, unlike printheads that only eject when a desired color dot is formed, processing printheads that need to eject for all colors are more prone to overheating. Printheads adjacent to such processing printheads are more likely to overheat, and their ink ejection volume may differ compared to printheads not adjacent to the processing printhead. As described above, by setting the difference between the maximum and minimum count values ​​of each printhead of the same color adjacent to the processing printhead to 1 or less, it is difficult for large differences in ink ejection volume to occur among multiple printheads of the same color.

[0265] In the above configuration, the processing head may also be configured such that a portion thereof is adjacent to the printhead in the main scanning direction and the transport direction. The plurality of printheads includes at least a first printhead that ejects ink of a first color and a second printhead that ejects ink of a second color. When the number of processing heads adjacent to the first printhead is greater than the number of processing heads adjacent to the second printhead, the first printhead ejects ink of the first color that has a smaller viscosity change due to temperature compared to the ink of the second color.

[0266] According to this inkjet recording device, the first ink head, which has a larger number of adjacent processing heads, ejects ink with minimal viscosity change due to temperature. Therefore, even if the first ink head is heated by the processing head, the temperature-induced changes in the ejection volume and ejection speed of the first color ink can be reduced.

[0267] In the above configuration, the processing head can also be configured in the central region of the configuration width of the printhead column in the main scanning direction.

[0268] Alternatively, the processing head may include: a pre-processing head disposed upstream of the one or more printhead columns in the transport direction for ejecting a pre-processing liquid as the processing liquid; and a post-processing head disposed downstream of the one or more printhead columns in the transport direction for ejecting a post-processing liquid as the processing liquid, wherein the pre-processing head and the post-processing head are configured such that the configuration or arrangement center of the one or more pre-processing heads in the main scanning direction coincides with the configuration or arrangement center of the one or more post-processing heads in the main scanning direction.

[0269] These inkjet recording devices can, in particular, reduce the time difference between the time from the pretreatment liquid falling onto the recording medium to the time from the ink falling at each main scanning position, as well as the time difference between the time from the ink falling to the time from the time of the posttreatment liquid falling.

[0270] In the inkjet recording device described above, it is also possible to: set the number of the pre-processing head and the post-processing head with more heads to m and the number of the less heads to n, satisfying the requirement that m = n + an odd number, and the configuration or arrangement center of the pre-processing head and the post-processing head is consistent with the configuration position of one of the multiple printheads in the main scanning direction.

[0271] According to this inkjet recording apparatus, the pre-processing head and post-processing head can be mounted on the carriage in a somewhat concentrated manner. This reduces the number of printheads located close to the processing head among multiple printheads. Therefore, the possibility of pre-processing liquid and post-processing liquid coming into contact with ink on the carriage can be reduced.

[0272] In the inkjet recording apparatus described above, the processing head may also include: a pre-processing head disposed upstream of the one or more printhead columns in the transport direction for ejecting a pre-processing liquid as the processing liquid; and a post-processing head disposed downstream of the one or more printhead columns in the transport direction for ejecting a post-processing liquid as the processing liquid. The inkjet recording apparatus further includes: a holding member for holding the carriage in a state capable of reciprocating along the main scanning direction, wherein the carriage includes a locking portion, and the carriage is held in a cantilevered state by the holding member through the locking portion. In the transport direction, the pre-processing head is disposed closer to the locking portion than the post-processing head.

[0273] According to this inkjet recording apparatus, by supporting the carriage in a cantilevered state with a holding member, the carriage can be supported with a simple structure. Furthermore, by supporting it in a cantilevered state, a structure with one side of the carriage open can be easily configured, facilitating easy maintenance of the printhead and processing head. When the carriage is supported in a cantilevered state, the accuracy estimation in the height direction decreases on the side away from the engagement portion of the carriage. However, since the post-processing head, which has a wider range of requirements for printhead accuracy, is mounted on the side away from the engagement portion, it is less likely to significantly affect image quality.

[0274] In the inkjet recording apparatus described above, the processing head may include: a pre-processing head disposed upstream of the one or more printhead columns in the transport direction for ejecting a pre-processing liquid as the processing liquid; and a post-processing head disposed downstream of the one or more printhead columns in the transport direction for ejecting a post-processing liquid as the processing liquid. The inkjet recording apparatus further includes: a holding member for holding the carriage in a state capable of reciprocating along the main scanning direction, wherein the carriage includes a locking portion, and the carriage is held in a cantilevered state by the holding member through the locking portion, and the one with fewer heads among the pre-processing head and the post-processing head is disposed on the locking portion side of the carriage.

[0275] As described above, the processing head generates heat due to the ejection action. Therefore, the carriage housing the processing head becomes heated, potentially causing thermal deformation of the carriage and its holding structure. In configurations where the carriage is held in a cantilevered state, this thermal deformation can sometimes affect ink delivery accuracy. According to the above configuration, the number of processing heads disposed on the base end side can be reduced, minimizing the impact of thermal deformation.

[0276] The inkjet recording device described above may also include a holding member that holds the carriage in a state where it can reciprocate along the main scanning direction. The carriage includes a locking portion, through which the carriage is held in a cantilevered state by the holding member. In the head arrangement of the printhead and the processing head, the head located on the side closest to the locking portion of the carriage is the processing head. The processing head is located in the head arrangement at a position other than the end in the main scanning direction.

[0277] According to this inkjet recording apparatus, in the head array (head mounting area), the head positioned closest to the engaging portion is the processing head, which is not positioned at the end of the head array 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. The above configuration makes this problem less likely to occur.

[0278] The inkjet recording apparatus described above may also include: a plurality of ink auxiliary containers for supplying ink to each of the plurality of printheads; and a processing liquid auxiliary container for supplying processing liquid to the processing head, wherein the plurality of ink auxiliary containers are mounted on the carriage in an arrangement along the main scanning direction, and the processing liquid auxiliary container is mounted on the carriage at a position on the transport direction different from that of the plurality of ink auxiliary containers.

[0279] According to the above configuration, the ink auxiliary container and the processing head auxiliary container are positioned at different locations in the transport direction, thus allowing the auxiliary containers to be arranged within a relatively narrow range on the carriage. Furthermore, the liquid in the auxiliary container, mounted on the carriage that reciprocates along the main scanning direction, is subjected to acceleration in the main scanning direction. The auxiliary container is connected to the head via a predetermined conduit; however, if the auxiliary containers are widely distributed on the carriage, the arrangement range of the conduit in the main scanning direction also increases, thus amplifying the effect of the acceleration and sometimes causing meniscus damage at the head's ejection portion. According to the above configuration, the arrangement range of the conduit in the main scanning direction can be made relatively narrow.

[0280] Furthermore, another aspect of the present invention relates to an inkjet recording method and an inkjet recording apparatus, wherein the inkjet recording apparatus includes: a transport unit for transporting a recording medium along a predetermined transport direction; a carriage for reciprocating along a main scanning direction intersecting the transport direction; one or more printhead arrays mounted on the carriage at predetermined positions along the transport direction; and a processing head mounted on the carriage for ejecting a non-coloring processing liquid, wherein each printhead array of the one or more printhead arrays includes a plurality of printheads arranged in a manner along the main scanning direction for ejecting ink for image formation, and the processing head has... The inkjet recording method includes: arranging the pretreatment head, which is configured upstream of the one or more printhead rows in the transport direction, ejects a pretreatment liquid as the processing liquid; configuring the pretreatment head in such a way that the head closest to one end in the main scanning direction is a one-end head, the head closest to the other end is a other-end head, the distance from the one-end head to the other end head in the main scanning direction is LC, and the distance from the one-end head to the pretreatment head in the main scanning direction is B1, such that the relationship |(B1-LC / 2)| / LC≤1 / 4 (Equation 1) is satisfied; ejecting the pretreatment liquid from the pretreatment head onto a predetermined recording area on the recording medium while moving the carriage toward the main scanning direction; and ejecting ink from the printhead onto the recording area that has been ejected with the pretreatment liquid while transporting the recording medium along the transport direction and moving the carriage along the main scanning direction.

[0281] According to this method, an inkjet recording apparatus that mounts pretreatment liquid and ink ejection heads on a carriage can effectively form an image on a recording medium. In particular, since the pretreatment head and ink head are sequentially arranged in the transport direction, the pretreatment liquid and ink can be ejected onto the recording medium in a desired landing order. Furthermore, by appropriately arranging the pretreatment head in accordance with Equation 1, the time difference from the landing of the pretreatment liquid to the landing of the ink can be reduced regardless of the carriage's direction of movement. As a result, differences in image quality on the recording medium are less likely to occur.

[0282] Furthermore, another aspect of the present invention relates to an inkjet recording method and an inkjet recording apparatus, wherein the inkjet recording apparatus includes: a transport unit for transporting a recording medium along a predetermined transport direction; a carriage for reciprocating along a main scanning direction intersecting the transport direction; one or more printhead arrays mounted on the carriage at predetermined positions along the transport direction; and a processing head mounted on the carriage for ejecting a non-coloring processing liquid, wherein each printhead array of the one or more printhead arrays includes a plurality of printheads arranged in a manner along the main scanning direction for ejecting ink for image formation, and the processing head has... The inkjet recording method includes: arranging the post-processing head, which is configured downstream of the one or more printhead rows in the transport direction, ejecting post-processing liquid as the processing liquid; configuring the post-processing head in such a way that the head closest to one end in the main scanning direction is a one-end head, the head closest to the other end is a other-end head, the distance from the one-end head to the other end head in the main scanning direction is LC, and the distance from the one-end head to the post-processing head in the main scanning direction is B2, such that the relationship |(B2-LC / 2)| / LC≤1 / 4 (Equation 2) is satisfied; while moving the carriage toward the main scanning direction, ejecting ink from the printhead to a predetermined recording area on the recording medium; while further transporting the recording medium along the transport direction and moving the carriage toward the main scanning direction, ejecting the post-processing liquid from the post-processing head to the recording area where the ink has been ejected.

[0283] According to this method, an inkjet recording device that mounts ink and post-processing liquid ejection heads on a carriage can effectively form an image on a recording medium. In particular, since the printhead and post-processing head are sequentially arranged in the transport direction, the ink and post-processing liquid can be ejected onto the recording medium in a desired landing sequence. Furthermore, by appropriately arranging the post-processing head according to Equation 2, the time difference from ink landing to post-processing liquid landing can be reduced regardless of the carriage's direction of movement. As a result, differences in image quality on the recording medium are less likely to occur.

[0284] According to the present invention, an inkjet recording apparatus and an inkjet recording method are provided, which have a carriage that carries a printhead and a processing head and moves along the main scanning direction, and are capable of reducing the time difference between ink landing and processing liquid landing.

[0285] Symbol Explanation

[0286] 1. Inkjet printer (printer head recording device)

[0287] 16. Synchronous belt (moving part)

[0288] 17. Guide rail (holding component)

[0289] 20. Workpiece conveying section (conveyor section)

[0290] 3. Carriages 3A to 3J

[0291] 31-head support frame

[0292] 32 Rear frame (clamping part)

[0293] 4. Printhead

[0294] 41 First Ink Head Column (Ink Head Column)

[0295] 42 Second Ink Head Column (Ink Head Column)

[0296] 43 Third Ink Head Column (Ink Head Column)

[0297] 4A to 4F First to Sixth Printheads

[0298] 4A1 to 4F1 upstream side

[0299] 4A2 to 4F2 Downstream side

[0300] 5. Pre-processing head (processing head)

[0301] 6. Post-processing head (processing head)

[0302] 7 Sub-containers

[0303] 7A to 7F Ink Sub-containers

[0304] 71. Sub-container for pretreatment solution

[0305] 72 Sub-container for post-treatment solution

[0306] F Conveying direction

[0307] S Main scanning direction

[0308] W - Workpiece (recording medium)

Claims

1. An inkjet recording device, characterized in that... include: The conveying unit transports the recording medium along the prescribed conveying direction; The carriage reciprocates along the main scanning direction, which intersects the conveying direction. One or more printhead rows are mounted on the carriage at predetermined positions in the transport direction; and A processing head, mounted on the carriage, is used to spray a non-coloring processing liquid, wherein... Each of the one or more printhead columns includes multiple printheads arranged in a manner along the main scanning direction for ejecting ink for image formation. The processing head includes a pretreatment head configured in the delivery direction upstream of the one or more printhead rows for ejecting a pretreatment liquid as the processing liquid. In the case that, among the plurality of printheads and the processing head, the head positioned closest to one end in the main scanning direction is designated as the one-end head, and the head positioned closest to the other end is designated as the other-end head, the distance from the one-end head to the other-end head in the main scanning direction is LC, and the distance from the one-end head to the pre-processing head in the main scanning direction is B1, the pre-processing head is configured in a manner that satisfies the relationship in Equation 1. |(B1-LC / 2)| / LC ≤ 1 / 4 (Equation 1).

2. The inkjet recording device according to claim 1, characterized in that, The preprocessing heads are arranged in a plurality of configurations along the main scanning direction, and at least one of the plurality of preprocessing heads is configured in a manner that satisfies the relationship described in Equation 1.

3. The inkjet recording device according to claim 2, characterized in that, The plurality of preprocessing heads are all configured in a manner that satisfies the relationship described in Equation 1.

4. The inkjet recording apparatus according to any one of claims 1 to 3, characterized in that, As the processing head, it also includes a post-processing head configured in the delivery direction downstream of the one or more printhead rows for ejecting a post-ejection liquid as the processing liquid. The printhead columns are arranged in multiple columns along the conveying direction. One of the printhead columns in this multi-column system has a printhead for ejecting ink of a specified color. The other ink head columns in the multiple ink head columns have other ink heads arranged adjacent to the one ink head and ejecting ink of the specified color. Assuming the distance from one end 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 following relationship: |(B1+B2-LC) / LC| ≤ 1 / 2.

5. An inkjet recording device, characterized in that... include: The conveying unit transports the recording medium along the prescribed conveying direction; The carriage reciprocates along the main scanning direction, which intersects the conveying direction. One or more printhead rows are mounted on the carriage at predetermined positions in the transport direction; and A processing head, mounted on the carriage, is used to spray a non-coloring processing liquid, wherein... Each of the one or more printhead columns includes multiple printheads arranged in a manner along the main scanning direction for ejecting ink for image formation. As the processing head, a post-processing head is provided, which is configured in the delivery direction downstream of the one or more printhead rows for ejecting a post-processing liquid as the processing liquid. Assuming that among the plurality of printheads and the processing head, the head positioned closest to one end in the main scanning direction is designated as the one-end head, and the head positioned closest to the other end is designated as the other-end head, the distance from the one-end head to the other-end head in the main scanning direction is LC, and the distance from the one-end head to the post-processing head in the main scanning direction is B2, the post-processing head is configured in a manner that satisfies the relationship in Equation 2. |(B2-LC / 2)| / LC ≤ 1 / 4 (Formula 2).

6. The inkjet recording apparatus according to claim 5, characterized in that, Multiple post-processing heads are arranged in the main scanning direction, and at least one of the multiple post-processing heads is configured in a manner that satisfies the relationship in Equation 2.

7. The inkjet recording apparatus according to claim 5 or 6, characterized in that, As the processing head, it also includes a pre-processing head configured in the conveying direction upstream of the one or more printhead rows for ejecting a pre-ejection liquid as the processing liquid. The printhead columns are arranged in multiple columns along the conveying direction. One of the printhead columns in this multi-column system has a printhead that ejects ink of a specified color. The other ink head columns in the multiple ink head columns have other ink heads arranged adjacent to the one ink head and ejecting ink of the specified color. Assuming the distance from one end head to the pre-processing head in the main scanning direction is B1, the pre-processing head and the post-processing head are configured in a manner that satisfies the following relationship: |(B1+B2-LC) / LC| ≤ 1 / 2.

8. The inkjet recording apparatus according to claim 5 or 6, characterized in that, As the processing head, it also includes a pre-processing head configured in the conveying direction upstream of the one or more printhead rows for ejecting a pre-ejection liquid as the processing liquid. Assuming the distance from one end of the head to the preprocessing head in the main scanning direction is B1, the preprocessing head is configured in a manner that satisfies the following relationship: |(B1-LC / 2)| / LC ≤ 1 / 4.

9. The inkjet recording apparatus according to claim 8, characterized in that, The printhead columns are arranged in multiple columns along the conveying direction. One of the printhead columns in this multi-column system has a printhead for ejecting ink of a specified color. The other ink head columns in the multiple ink head columns have other ink heads arranged adjacent to the one ink head and ejecting ink of the specified color. The preprocessing head and the postprocessing head are configured in a manner that satisfies the following relationship: |(B1+B2-LC) / LC| ≤ 1 / 3.

10. The inkjet recording apparatus according to any one of claims 1 to 9, characterized in that, The processing head is configured within the configuration width of the plurality of printheads in the main scanning direction.

11. The inkjet recording apparatus according to any one of claims 1 to 10, characterized in that, The processing head is configured such that a portion of it enters between a pair of printheads, which are adjacent printheads in the main scanning direction among the plurality of printheads contained in the printhead column.

12. The inkjet recording apparatus according to any one of claims 1 to 11, characterized in that, The processing head is configured such that a portion of it is adjacent to the printhead in both the main scanning direction and the transport direction. The plurality of printheads includes multiple printheads of the same color that eject ink of the same color. When counting the number of adjacent processing heads in the main scanning direction and the transport direction for each of the same color inkheads, the difference between the maximum and minimum values ​​of their counts is less than 1.

13. The inkjet recording apparatus according to any one of claims 1 to 12, characterized in that, The processing head is configured such that a portion of it is adjacent to the printhead in both the main scanning direction and the transport direction. The plurality of printheads includes at least a first printhead that ejects ink of a first color and a second printhead that ejects ink of a second color. When the number of processing heads adjacent to the first ink head is greater than the number of processing heads adjacent to the second ink head, the first ink head ejects ink with a smaller viscosity change due to temperature compared to the ink of the second color as the ink of the first color.

14. The inkjet recording apparatus according to any one of claims 1 to 13, characterized in that, The processing head is configured in the central region of the printhead array in the main scanning direction.

15. The inkjet recording apparatus according to any one of claims 1 to 14, characterized in that, The processing head includes: A pretreatment head, configured upstream of the one or more printhead rows in the transport direction, is used to eject a pretreatment liquid as the treatment liquid; and, A post-processing head, configured downstream of the one or more printhead rows in the conveying direction, is used to eject a post-processing liquid as the processing liquid, wherein... The preprocessing head and the postprocessing head are configured such that the configuration or arrangement center of one or more of the preprocessing heads in the main scanning direction is aligned with the configuration or arrangement center of one or more of the postprocessing heads in the main scanning direction.

16. The inkjet recording apparatus according to claim 15, characterized in that, When the number of headers with more characters in the preprocessing header and the number of headers with fewer characters is set to m, and the number of headers with fewer characters is set to n, the requirement that m = n + an odd number is satisfied. The configuration or arrangement center of the pre-processing head and the post-processing head is consistent with the configuration position of one of the multiple printheads in the main scanning direction.

17. The inkjet recording apparatus according to any one of claims 1 to 16, characterized in that, The processing head includes: A pretreatment head, configured upstream of the one or more printhead rows in the transport direction, is used to eject a pretreatment liquid as the treatment liquid; and, A post-processing head, configured in the conveying direction downstream of the one or more printhead rows, is used to eject a post-processing liquid as the processing liquid. The inkjet recording apparatus further includes: a holding member that holds the carriage in a state capable of reciprocating along the main scanning direction, wherein... The carriage includes a locking portion, through which the carriage is held in a cantilevered state by the retaining member. In the conveying direction, the pre-processing head is positioned closer to the engaging portion than the post-processing head.

18. The inkjet recording apparatus according to any one of claims 1 to 17, characterized in that, The processing head includes: A pretreatment head, configured upstream of the one or more printhead rows in the transport direction, is used to eject a pretreatment liquid as the treatment liquid; and, A post-processing head, configured in the conveying direction downstream of the one or more printhead rows, is used to eject a post-processing liquid as the processing liquid. The inkjet recording apparatus further includes: a holding member that holds the carriage in a state capable of reciprocating along the main scanning direction, wherein... The carriage includes a locking portion, through which the carriage is held in a cantilevered state by the retaining member. The pre-processing head and the post-processing head, whichever has fewer heads, are positioned on the engaging side of the carriage.

19. The inkjet recording apparatus according to any one of claims 1 to 18, characterized in that... Also includes: A holding component holds the carriage in a state where it can reciprocate along the main scanning direction, wherein... The carriage includes a locking portion, through which the carriage is held in a cantilevered state by the retaining member. In the head arrangement of the printhead and the processing head, the head located on the side closest to the engaging portion of the carriage is the processing head, which is positioned in the head arrangement except at the end in the main scanning direction.

20. The inkjet recording apparatus according to any one of claims 1 to 19, characterized in that... Also includes: Multiple ink sub-containers supply ink to each of the multiple ink heads; and A secondary container for the processing liquid supplies the processing liquid to the processing head, wherein... The plurality of ink auxiliary containers are mounted on the carriage in an arrangement along the main scanning direction, and the processing liquid auxiliary container is mounted on the carriage at a position different from the plurality of ink auxiliary containers in the transport direction.

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