Liquid discharge device and liquid discharge method

Abstract

To provide a liquid discharge device that suppresses color mixing between color ink and white ink in DTF-type printing and prevents deterioration of image quality.SOLUTION: A liquid discharge device includes: first discharge means that discharges color ink onto a transfer base material for transferring an image to a printing object; second discharge means that discharges white ink that becomes an underlayer for the color ink when the image is transferred to the printing object onto the transfer base material; third discharge means that discharges a treatment liquid containing a coagulant onto the transfer base material; and a control unit. The control unit calculates, based on image data, a total amount of adhesion of the color ink and the white ink for each predetermined region, and performs control so as to discharge the treatment liquid onto a region where the total amount of adhesion of the color ink and the white ink exceeds a predetermined threshold value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a liquid ejection apparatus and a liquid ejection method. [Background technology]

[0002] 2. Description of the Related Art Known liquid ejection devices include inkjet recording devices that use inkjet technology, and DTF (Direct To Film) type printers.

[0003] In DTF printing, ink is applied to a transfer substrate such as film, a heat-soluble adhesive powder is applied, and the adhesive powder is melted by heating. The print target is then placed on the film and heated and pressurized to transfer the image to the print target.

[0004] In DTF printing, techniques have been proposed to prevent a decline in image quality after transfer. For example, Patent Document 1 discloses the use of a clear ink that does not affect the color of the image in addition to color inks. Patent Document 1 also attempts to prevent an insufficient amount of hot melt resin powder (adhesive powder) from adhering, to more appropriately transfer the image, and to prevent a decline in image quality after transfer. Summary of the Invention [Problem to be solved by the invention]

[0005] In DTF printing, white ink may also be used in addition to clear ink, and color inks and white ink may be applied to the film to form an image for transfer. The white ink is used as a base for the color ink on the printed material, allowing the image to be properly expressed on the printed material even if the printed material is dark in color.

[0006] However, with conventional technology, there was a problem in that the color inks and white inks mixed together, which caused color unevenness and reduced image quality. The film used as the transfer substrate is often provided with an ink-receiving layer, which has an upper limit to the amount of ink that can be received by the ink-receiving layer. If more ink than the upper limit is applied, the color inks and white ink will mix on the film, resulting in color unevenness (see Figure 7(A)). If color unevenness occurs on the film when the image is transferred to a recording medium, the transferred image will also have color unevenness (see Figure 7(B)).

[0007] One way to prevent this type of color mixing is to reduce the amount of ink applied, but if the amount of color ink is reduced, the color gamut that can be expressed becomes smaller, making it impossible to express dark colors, for example. If the amount of white ink is reduced, the color of the recording medium will affect the image. If color ink and white ink mix, image quality will decrease.

[0008] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a liquid ejection device that suppresses color mixing between color inks and white ink in DTF printing, thereby preventing degradation of image quality. [Means for solving the problem]

[0009] In order to solve the above problems, the liquid ejection device of the present invention comprises a first ejection means that ejects color inks onto a transfer substrate that transfers an image onto a substrate, a second ejection means that ejects white ink onto the transfer substrate that will serve as a base for the color inks when the image is transferred to the substrate, a third ejection means that ejects a treatment liquid containing a coagulant onto the transfer substrate, and a control unit that controls the ejection of the color inks, the white ink, and the treatment liquid, wherein the control unit calculates the total amount of adhesion of the color inks and the white ink for each specified area based on image data, and controls the ejection of the treatment liquid onto areas where the total amount of adhesion of the color inks and the white ink exceeds a specified threshold. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a liquid ejection device that suppresses color mixing between color inks and white ink in DTF printing, thereby preventing degradation of image quality. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view of a liquid ejection device according to an embodiment of the present invention, with the cover members in a closed state. [Figure 2] FIG. 2 is a plan view of the liquid ejection device of FIG. [Figure 3] FIG. 2 is a perspective view of the liquid ejection device with the cover members open. [Figure 4] FIG. 4 is a plan view of the liquid ejection device of FIG. [Figure 5] 10 is a flow chart of a conventional example. [Figure 6] 1A to 1C are diagrams illustrating printing in a conventional DTF system. [Figure 7] 10A and 10B are diagrams showing an example in which color ink and white ink are mixed together. [Figure 8] 1 is a flow according to an embodiment of the present invention. [Figure 9] 1A to 1C are diagrams illustrating DTF printing according to one embodiment of the present invention. [Figure 10] 10 is a flowchart illustrating a process for determining an area onto which a treatment liquid is to be discharged according to an embodiment of the present invention. [Figure 11] 1A and 1B are diagrams illustrating an example of dividing an entire image forming area according to an embodiment of the present invention. [Figure 12] 10A and 10B are diagrams illustrating an example in which an image is formed on a printing substrate using white ink. [Figure 13] 10 is an example of an image produced by a conventional method. [Figure 14] FIG. 10 is a diagram illustrating an example of the amount of ink adhesion. [Figure 15] 1 is an example of an image produced according to one embodiment of the present invention. [Figure 16] An example of a second test chart (A) and an example of a transfer image (B). [Figure 17] This is an example of a case where streaks occur in an image to be transferred. [Figure 18] This is an example of determining the amount of treatment liquid to be applied. [Figure 19] 10A and 10B are diagrams illustrating an example in which treatment liquid is dotted onto an image formation area. [Figure 20] 10A and 10B are diagrams illustrating an example of an operation for discharging a treatment liquid. [Figure 21] 10A and 10B are diagrams illustrating another example of the operation of discharging the treatment liquid. DETAILED DESCRIPTION OF THE INVENTION

[0012] The liquid ejection device and the liquid ejection method according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the following embodiments, and other modifications, additions, corrections, deletions, and other changes can be made within the scope of what a person skilled in the art can conceive. Any aspect is within the scope of the present invention as long as it achieves the functions and effects of the present invention.

[0013] The liquid ejection device of the present invention comprises a first ejection means that ejects color inks onto a transfer substrate that transfers an image onto a substrate, a second ejection means that ejects white ink onto the transfer substrate, which will serve as a base for the color inks when the image is transferred to the substrate, a third ejection means that ejects a treatment liquid containing a coagulant onto the transfer substrate, and a control unit that controls the ejection of the color inks, the white ink, and the treatment liquid, wherein the control unit calculates the total amount of adhesion of the color inks and the white ink for each specified region based on image data, and controls the ejection of the treatment liquid onto regions where the total amount of adhesion of the color inks and the white ink exceeds a specified threshold.

[0014] The liquid ejection method of the present invention includes a first ejection step of ejecting color inks onto a transfer substrate that transfers an image onto a substrate; a second ejection step of ejecting white ink onto the transfer substrate, which will serve as a base for the color inks when the image is transferred to the substrate; a third ejection step of ejecting a treatment liquid containing a coagulant onto the transfer substrate; and a control step of controlling the ejection of the color inks, the white ink, and the treatment liquid, wherein the control step calculates the total amount of adhesion of the color inks and the white ink for each specified region based on image data, and controls the ejection of the treatment liquid onto regions where the total amount of adhesion of the color inks and the white ink exceeds a specified threshold.

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding parts are designated by the same reference numerals, and redundant explanations thereof will be appropriately simplified or omitted. The terms "printing substrate" and "recording medium" are synonymous. In addition, the following description mainly focuses on control by the control unit, but by appropriately interpreting "control by the control unit" as a control process, the description of the configuration of the liquid ejection device can be applied to the configuration of the liquid ejection method.

[0016] Fig. 1 shows a perspective view of the liquid ejection device 1 with all cover members closed, and Fig. 2 shows a plan view. Fig. 3 shows a perspective view of the liquid ejection device 1 with the cover members open, and Fig. 4 shows a plan view. In Fig. 1, direction X is the front-to-rear direction of the liquid ejection device or the sub-scanning direction or the transport direction of the transfer substrate, direction Y is the width direction of the liquid ejection device or the main scanning direction, and direction Z is the up-down direction. Directions X and Y are parallel to the liquid ejection surface of the transfer substrate placed on the stage, but some error is allowed. Directions X, Y, and Z are perpendicular to each other.

[0017] As shown in Figures 1 and 2, the liquid ejection device 1 has a stage 3 in front of a housing 2. The stage 3 is mounted on guide rails 4. The guide rails 4 extend in direction X. An operation panel 5 is provided on the front side of the housing 2. An ink cartridge 6 is detachably attached to the side of the housing 2. A front cover 7 and a rear cover 8 are provided above the housing 2 as cover members.

[0018] The top surface of stage 3 is a flat mounting surface on which the transfer substrate is placed. The top surface of stage 3 is a surface parallel to the X and Y directions. Stage 3 moves on guide rails 4 and is provided so that it can move back and forth in both directions of the X direction. Stage 3 is also provided so that it can move up and down in the Z direction. This allows the height of the transfer substrate placed on stage 3 to be adjusted.

[0019] The front cover 7 and the rear cover 8 are provided so as to be movable in both directions X. The state shown in FIG. 1, in which the front cover 7 has moved rearward and the rear cover 8 has moved forward, is the state in which the respective covers are closed. In contrast, the state shown in FIG. 3, in which the front cover 7 has moved forward and the rear cover 8 has moved rearward, is the state in which the respective covers are open. By configuring the front cover 7 and the rear cover 8 to open and close by sliding in this way, the area occupied by the liquid ejection device, including the opening and closing area of ​​the cover members, can be made smaller compared to a configuration in which the cover members open and close vertically, for example. The front cover 7 and the rear cover 8 have openings at both ends in the front-to-rear direction. When the front cover 7 and the rear cover 8 are closed, the front cover 7 and the rear cover 8 are arranged consecutively in the front-to-rear direction.

[0020] 3 and 4, the device main body 50 of the liquid ejection device 1 includes a housing 2, and liquid ejection units 9A and 9B provided on the housing 2. In this embodiment, the device main body 50 is the portion of the liquid ejection device 1 other than the front cover 7 and rear cover 8. The front cover 7 and rear cover 8 are provided on the device main body 50 so as to be slidable in the X direction.

[0021] Opening the front cover 7 and rear cover 8 exposes the liquid ejection unit within the liquid ejection device 1 to the outside. Exposing the liquid ejection unit to the outside allows cleaning of the maintenance unit 30, the liquid ejection head, and their surroundings, or replacement of the carriage. Furthermore, the front cover 7 and rear cover 8 are closed during image formation. This covers the liquid ejection units 9A and 9B, preventing external access to the carriages and other operating parts of the liquid ejection units 9A and 9B. Furthermore, locating the liquid ejection units 9A and 9B in a closed space within the front cover 7 or rear cover 8 prevents ink mist from scattering to the surrounding area during liquid ejection. Fans installed in the liquid ejection units 9A and 9B circulate airflow within the front cover 7 or rear cover 8, allowing the generated ink mist to be circulated and collected within the front cover 7 or rear cover 8.

[0022] The liquid ejection device 1 of this embodiment has two liquid ejection units 9A and 9B in the direction X. The liquid ejection unit 9A ejects color and white inks. The liquid ejection unit 9B ejects treatment liquid. Note that the liquids ejected by the liquid ejection units 9A and 9B are not limited to those described above, and they may eject any of the color inks, white ink, and treatment liquid.

[0023] Because liquid dischargers 9A and 9B have the same configuration, the following description will focus on liquid discharger 9A. Liquid discharger 9A has a carriage 10A, a guide rod 11, an electrical component section 12 consisting of a circuit board, an electrical component cover, etc., and a maintenance unit 30. Liquid dischargers 9A and 9B or carriages 10A and 10B will also be simply referred to as liquid discharger 9 or carriage 10.

[0024] The guide rod 11 extends in the main scanning direction. The carriage 10 is provided so as to be movable in the main scanning direction along the guide rod 11. The carriage 10 has a plurality of liquid ejection heads. The maintenance unit 30 is provided opposite the guide rod 11, outside the liquid ejection area on one side in the left-right direction.

[0025] The maintenance unit 30 has a wiping member that cleans the nozzle surface of the liquid ejection head, a suction mechanism that sucks the nozzle surface, etc. The wiping member may be a wiper made of rubber or the like, or a web made of nonwoven fabric or the like.

[0026] An example of the process of forming an image using the liquid ejection head described above will now be described. First, the transfer substrate is placed on stage 3 and transported on guide rails 4. It is then transported to the front side of the liquid ejection device, where color ink is ejected onto the transfer substrate by liquid ejection unit 9A. Specifically, while carriage 10A is moved in the main scanning direction along guide rod 11, color ink is ejected onto the transfer substrate from nozzles provided in the liquid ejection head in the main scanning direction. This is repeated at each position in the sub-scanning direction, thereby applying color ink to the transfer substrate.

[0027] Thereafter, while moving the stage 3 backward, the liquid discharger 9B discharges the treatment liquid in the same manner. Next, while moving the stage 3 forward, the liquid discharger 9A discharges the white ink onto the transfer substrate in the same manner. This allows the transfer image to be formed on the transfer substrate.

[0028] The liquid ejection device 1 of this embodiment is capable of ejecting not only color inks and white ink, but also treatment liquid. The liquid ejection device 1 of this embodiment is equipped with first to third ejection means for ejecting liquids (color inks, white ink, treatment liquid), and the liquid ejection head is an example of the ejection means. The treatment liquid used in this embodiment contains an aggregating agent that aggregates the white ink. The treatment liquid may also be referred to as a pretreatment liquid, etc.

[0029] The liquid ejection device 1 of this embodiment is also capable of DTG (Direct to Garment) printing. In this case, instead of a transfer substrate, a recording medium such as fabric is set on the stage 3 and liquid is ejected onto it. The liquid ejection device of the present invention is not limited to the above example, and may also be configured to include a liquid ejection head that ejects treatment liquid onto a roll-to-roll printer.

[0030] Next, before describing the detailed example of this embodiment, a conventional example will be described. FIG. 5 is a flow chart showing a conventional example of DTF (Direct to Film) printing. In S1, color ink is ejected onto a film serving as a transfer substrate. In S2, white ink is ejected onto the film on which the color inks have been ejected, forming a layer of color ink on the film and a layer of white ink on the color ink layer. In S3, powder (adhesive) is applied to the film. An adhesive layer made of adhesive is formed on the white ink layer. For example, hot melt resin powder is used as the adhesive. In S4, heat treatment is performed to melt the powder. In S5, the image on the transfer substrate is transferred to a print substrate (e.g., a recording medium), forming an image on the print substrate. Examples of print substrates include fabrics such as T-shirts and tote bags. DTF printing is expected to form high-quality images on fabrics.

[0031] FIG. 6 is a schematic cross-sectional view for explaining printing in the DTF method of the prior art. As shown in (A), color inks are ejected onto a film 61 serving as a transfer substrate to form a color ink layer 51a, and then white ink 52 is ejected to form a white ink layer 52a. The color inks and white ink are ejected, for example, by a liquid ejection head 60.

[0032] The DTF method is a printing method in which an image on a film 61 is transferred to a substrate to form an image, so a layer of color ink and a layer of white ink are formed on the film 61 in a mirror image. The main reason for ejecting white ink is to avoid being affected by the color of the substrate to which the image is transferred. The white ink layer is used as a base for the color ink layer on the substrate.

[0033] Next, as shown in (B), powder 62 is applied to the image to be transferred on film 61, and heat is applied to melt powder 62. Next, as shown in (C), a recording medium 63 as a printing substrate is placed on the film 61, and heat and pressure are applied to transfer the image on the film 61 to the recording medium 63. By peeling off the film 61, the desired image can be formed on the recording medium 63. The recording medium 63 can be, for example, fabric such as a T-shirt.

[0034] A typical film 61 has an ink-receiving layer formed thereon, and there is an upper limit to the amount of ink that the ink-receiving layer can receive. In conventional examples, ink may be ejected in excess of the upper limit, and exceeding the upper limit results in color mixing of the color ink and white ink. When color ink and white ink mix on the film 61, color unevenness occurs, and if the image is transferred to the recording medium 63 in this state, the transferred image also has color unevenness.

[0035] FIG. 7 is a diagram illustrating an example of color unevenness occurring in conventional DTF printing. (A) is a diagram illustrating the state when ink (color ink and white ink) exceeding the upper limit is actually applied to film 61. Although it is difficult to see on the paper, the color ink and white ink mix on the film, resulting in color unevenness. (B) is a diagram illustrating the state when the image in (A) is transferred to recording medium 63. Although it is difficult to see on the paper, color unevenness also occurs in the image after transfer to the recording medium. There is a difference in the image between the center of the transferred image and the periphery of the center.

[0036] A detailed example of this embodiment will be described. The liquid ejection device of this embodiment has a first ejection means that ejects color ink onto a transfer substrate that transfers an image onto a substrate, a second ejection means that ejects white ink onto the transfer substrate that serves as a base for the color ink when the image is transferred to the substrate, a third ejection means that ejects a treatment liquid containing a coagulant onto the transfer substrate, and a control unit that controls the ejection of the color ink, the white ink, and the treatment liquid. The control unit in this embodiment calculates the total amount of the color ink and the white ink adhered to each specified area based on image data, and controls the ejection of the treatment liquid onto areas where the total amount of the color ink and the white ink adhered exceeds a specified threshold.

[0037] Color inks, white ink, and treatment liquid are ejected onto a transfer substrate to form an image to be transferred. If necessary, an adhesive is applied to the image to be transferred, and the adhesive is melted by heating. The adhesive is preferably a powder, and powder adhesives are sometimes referred to as powder, adhesive powder, etc. The print substrate is placed on the transfer substrate, and heat and pressure are applied as necessary, to transfer the image to be transferred to the print substrate. The process of transferring the image to be transferred to the print substrate may also be referred to as a transfer process, etc.

[0038] The adhesive can be appropriately selected, for example, a hot-melt resin powder. An adhesive layer is formed by applying the adhesive to the transfer substrate. The application method is not particularly limited and can be appropriately selected. The printing substrate can be appropriately selected, and examples include fabrics or materials such as T-shirts, tote bags, etc. The printing substrate may also be referred to as a medium, a recording medium, etc. The treatment liquid may contain an aggregating agent and may be selected as appropriate. The treatment liquid may also be referred to as a pretreatment liquid. The aggregating agent may be selected as appropriate, and known aggregating agents may be used. The aggregating agent in this embodiment aggregates the white ink. The color ink and the white ink can be appropriately selected, and known inks can be used. The color ink may be one type or multiple types.

[0039] In this embodiment, the total amount of color ink and white ink attached is calculated for each predetermined area based on image data, and treatment liquid is ejected onto areas where the total amount of color ink and white ink attached exceeds a predetermined threshold. In other words, based on the determination results for the area to which treatment liquid is ejected, treatment liquid is applied only to areas where color mixing of color ink and white ink may occur. As a result, treatment liquid can be ejected onto the necessary areas, color mixing of color ink and white ink can be suppressed, and a decrease in image quality can be prevented.

[0040] Furthermore, in this embodiment, since the ejection of treatment liquid can be omitted in areas where color ink and white ink do not mix, the amount of treatment liquid used can be reduced, and cost reductions can be expected. Furthermore, by omitting the ejection of treatment liquid in areas where color ink and white ink do not mix, productivity can be expected to improve.

[0041] The predetermined area can be selected as appropriate. The total amount of color ink and white ink applied to each predetermined area may be, for example, the sum of the amounts of color ink and white ink applied per unit area.

[0042] 8 shows an example of a flow of this embodiment, in which the description of the process for determining whether or not to eject the treatment liquid is omitted.

[0043] In S11, color inks are ejected onto a film serving as a transfer substrate. In S12, a processing liquid is ejected onto the film onto which the color ink has been ejected. In S13, white ink is ejected onto the film onto which the color inks and processing liquid have been ejected, thereby forming an image to be transferred onto the film. In S14, powder (adhesive) is applied to the film, forming an adhesive layer on the white ink layer. In S15, heat treatment is performed to melt the powder. In S16, the image to be transferred on the film is transferred to a printing substrate (e.g., a recording medium), forming an image on the printing substrate. As in the conventional example, the printing substrate may be fabric such as a T-shirt or a tote bag. In this embodiment, a high-quality image can be formed on the fabric.

[0044] 8 is a preferred example in this embodiment. In the above example, the color ink, treatment liquid, and white ink are ejected in this order, but the present invention is not limited to this. For example, the color ink, white ink, and treatment liquid may be ejected in this order. However, when the color ink, treatment liquid, and white ink are ejected in this order, as in the above example, it is possible to further suppress the mixing of the color ink and white ink.

[0045] A preferred example of this embodiment will be described again. In this example, when ejecting treatment liquid onto an area where the total amount of color ink and white ink adhered exceeds a predetermined threshold, the control unit preferably controls the ejection onto the transfer substrate in the order of color ink, treatment liquid, and white ink. In this case, by ejecting the white ink after ejecting the treatment liquid having the effect of aggregating the white ink, it is possible to further suppress the mixing (mixing) of the color inks and the white ink. In such an example, the treatment liquid may be referred to as a pretreatment liquid.

[0046] 9 is a schematic cross-sectional view for explaining an example of forming an image to be transferred in this embodiment. The difference from the above-mentioned conventional example is that, for example, a treatment liquid is ejected.

[0047] As shown in (A), color ink 51 is ejected onto film 61, which serves as a transfer substrate. The color ink 51 ejected onto film 61 forms a color ink layer 51a on film 61. In the figure, the color ink droplets and the color ink on film 61 are given different reference numerals to distinguish them. The color ink is ejected by liquid ejection head 71, which is the first ejection means.

[0048] Next, as shown in (B), treatment liquid 53 is ejected onto film 61. The ejected treatment liquid 53 is applied onto color ink layer 51a (reference numeral 53a). In the figure, droplets of the treatment liquid and the treatment liquid on film 61 are given different reference numerals to distinguish them. The treatment liquid is ejected by a liquid ejection head 73, which is a third ejection means.

[0049] Next, as shown in (C), white ink 52 is ejected onto film 61. The white ink 52 ejected onto film 61 forms a white ink layer 52a on film 61. In the figure, the white ink droplets and the white ink on film 61 are given different reference numerals to distinguish them. The white ink is ejected by liquid ejection head 72, which is the second ejection means.

[0050] In this embodiment, by utilizing the aggregating effect of the treatment liquid, the white ink can be aggregated before the color inks and the white ink mix, thereby preventing the color inks and the white ink from mixing (mixing).

[0051] Although the transfer process is not shown, it can be carried out in the same manner as in the conventional example shown in Figure 6. Adhesive powder 62 is applied to the image to be transferred on film 61, and heat is applied to melt the powder 62. Next, a recording medium 63 as the printing substrate is placed on film 61, and heat and pressure are applied to transfer the image on film 61 to recording medium 63. The desired image can be formed on recording medium 63 by peeling off film 61.

[0052] FIG. 10 is a flow chart showing an example of a determination process for ejection of treatment liquid. In S21, image data is read in. There are no particular restrictions on the image data, and examples include JPEG and PNG. In S22, printing conditions are determined, such as print settings, print position, size, etc. In S23, RGB values ​​are obtained from the image data. In S24, the acquired RGB values ​​are converted into CMYK values. In S25, the positions where the color inks and white ink are to be dropped from the liquid ejection head are determined based on the converted CMYK values. The "drop positions" may also be referred to as the positions where the liquid droplets are to land.

[0053] In S26, the entire area where the image is to be formed is divided into N predetermined areas. When dividing into N predetermined areas, for example, the entire image forming area is divided into N unit areas. N can be selected as appropriate. The divided areas are also referred to as image forming areas.

[0054] 11 is a diagram illustrating an example of dividing the entire image formation area. (A) shows the entire image formation area, with the reference numeral 80 indicating the entire image formation area. (B) shows the entire image formation area 80 divided into N parts, with the reference numeral 81 indicating the divided image formation areas. For ease of understanding, both the entire image formation area 80 and the image formation area 81 are square. The entire image formation area 80 is the area onto which color inks and white ink are ejected. The image formation area 81 is, for example, an area divided by a unit area.

[0055] In S27, the total amount of ink adhesion in each image forming area is calculated. The total amount of ink adhesion is the total amount of color ink and white ink adhesion, and is the sum of the amount of color ink adhesion and the amount of white ink adhesion. The total amount of ink adhesion is also referred to as the total ink adhesion amount. For example, the total ink adhesion amount in the image forming area 81 shown in FIG. 11(B) is calculated.

[0056] In S28, n is set to 1. In S29, the ink adhesion amount is determined for the nth image formation area. In the determination in S29, it is determined whether the total ink adhesion amount in the nth image formation area exceeds a threshold. If the total ink adhesion amount exceeds the threshold (if the determination in S29 is YES), S30 is performed. If the total ink adhesion amount does not exceed the threshold (if the determination in S29 is NO), S30 is not performed and S31 is performed. The threshold can be determined, for example, using a test chart described below.

[0057] In the determination in S29, it is determined whether the total amount of ink adhered in the image formation area exceeds a threshold value, but this may be changed to determine whether it is equal to or greater than the threshold value. Depending on how the threshold value is determined, it is possible to appropriately select whether to determine whether it exceeds the threshold value or whether it is equal to or less than the threshold value.

[0058] In S30, the positions where the treatment liquid is to be ejected from the liquid ejection head onto the n-th image formation region are determined. Note that the method for determining the positions where the treatment liquid is to be ejected can be selected as appropriate, and for example, as will be described later, the treatment liquid may be ejected randomly so that pixels do not overlap.

[0059] In S31, it is determined whether n is N. If n is N, the flow ends, and if n is not N, n is incremented (S32) and the process of S29 is repeated. That is, the determination of S29 is made in order of n=1, 2, 3, . . . , N, and it is determined that the image formation area where the total ink adhesion amount exceeds the threshold is the area onto which treatment liquid is to be ejected.

[0060] In this way, the area to which the treatment liquid is to be discharged is determined, and the treatment liquid is discharged onto the determined area. The processing of the flow in Fig. 10 is performed, for example, before S11 in Fig. 8. The processing of the flow in Fig. 10 may be performed between S11 and S12 in Fig. 8, but it is preferable to perform it before S11, and to determine the area to which the treatment liquid is to be discharged at the time of S11.

[0061] The white ink serves as a base for the color inks when the image is transferred to the printing substrate. The amount of white ink to be applied as the base can be selected as appropriate. For example, the amount of white ink applied may be the same as that used when printing a White (R, G, B) = (255, 255, 255) image on the printing substrate, and the ink may be ejected onto the transfer substrate.

[0062] FIG. 12 is a diagram showing an example of an image formed on a black T-shirt using White (R, G, B) = (255, 255, 255). The illustrated example shows an image 64 formed on a black T-shirt, which is a recording medium 63, by transferring an image formed on a film 61 onto which only white ink has been ejected. As shown in the figure, the black color of the recording medium 63 is concealed. With such a white ink image 64, even if a layer of color ink is formed on top of the image 64, the desired image can be formed on the recording medium 63 without being affected by the color of the black T-shirt fabric. Image 64 is an example of an image for determining the amount of white ink applied, and may be, for example, a solid image as shown in the figure.

[0063] The above-mentioned preferable example of the amount of deposited white ink will be described again. It is preferable that the amount of white ink adhered is determined by the following method for specifying the amount of white ink adhered, and that the control unit controls the ejection of the white ink at the amount of adhesion determined by the following method for specifying the amount of white ink adhered. [How to determine the amount of white ink attached] The white ink is ejected onto the transfer substrate in an arbitrary amount of adhesion to form an image for specifying the amount of adhesion, the image for determining the amount of adhesion is transferred to the printed material, and an adhesion amount that is not affected by the color of the printed material is specified using an arbitrary judgment method.

[0064] In this way, it is possible to prevent the image formed on the printing substrate from being affected by the color of the printing substrate, and to form an image with high color reproducibility.

[0065] Next, a comparison between an image produced in a conventional example and an image produced in the present embodiment will be explained using figures. The images actually produced are in color, but for convenience, the figures are shown in black and white.

[0066] FIG. 13 is a diagram illustrating a conventional example. The example shown in FIG. 13 is an example of a case where an image was formed using the method shown in FIGS. 5 and 6, for example, and no treatment liquid was used. In FIG. 13, No. 1 is image data for evaluation, No. 2 is an image to be transferred formed on a film (transfer substrate), No. 3 is the state after powder has been applied, and No. 4 is the state after the image to be transferred has been transferred to a recording medium (printing substrate). Note that, because the film is printed in a mirror image, (1) to (8) in Nos. 2 and 3 are reversed left and right compared to (1) to (8) in Nos. 1 and 4. In Nos. 2 and 3, only (1), (4), (5), and (8) are shown for ease of viewing.

[0067] FIG. 14 is a diagram for explaining the evaluation images (patches) in the example shown in FIG. 13. (1) to (8) in FIG. 14 correspond to (1) to (8) of No. 1 in FIG. 13. The evaluation images (patches) were solid images measuring 4 cm x 4 cm. The color ink deposition amount for each patch was the value shown in FIG. 14, and the white ink deposition amount serving as the background was the same for each patch, and was the value shown in FIG. 14. Patch (8) was a white image as a reference example. Therefore, the color ink deposition amount was set to 0.

[0068] In the conventional example shown in Figure 13, although it is difficult to see due to the monochrome paper surface, color ink and white ink have mixed in the patches (3) Ye, (5) Red, and (6) Green, resulting in color unevenness. This is particularly evident in the patch No. 4 (5) Red in Figure 13 (bottom left), where there is a difference in the image between the center and the periphery of the patch.

[0069] Furthermore, in the conventional example shown in Figure 13, even at the No. 2 and No. 3 stages, there were patches where the color ink and white ink were mixed. In particular, the (5) Red patch (bottom right) in No. 2 exhibited color unevenness to the extent that the white ink was clearly concentrated on the outer periphery of the patch. In the conventional example, the color ink and white ink were not clearly separated on the film, and there were patches where the color ink and white ink were mixed, causing unevenness in the color ink layer and white ink layer. As a result, in the conventional example, the white ink layer did not function as a base, resulting in poor image quality. As a result, some of the transferred images (No. 4) also exhibited color unevenness.

[0070] As shown in Figure 14, the amount of color ink attached to the patches (3) Ye, (5) Red, and (6) Green, which have color unevenness, is large. As shown in the figure, the amount of color ink attached to the patches (3), (5), and (6) is 2.8 × 10 -3 cc / cm 2 ~6.7×10 -3 cc / cm 2 This is the amount of white ink attached (2.4 x 10 -3 cc / cm 2 From these results, it is believed that the total amount of color ink and white ink attached was so large that the ink receiving layer of the film (transfer substrate) could not absorb it, making the ink prone to bleeding.

[0071] Based on the above findings, the example of this embodiment was carried out taking into consideration the total amount of ink adhesion. FIG. 15 is a diagram for explaining an example of this embodiment. The example shown in FIG. 15 is an example produced, for example, as shown in FIGS. 8 to 10, and an image was formed using a treatment liquid. No. 1 (1) to (8) in FIG. 15 correspond to (1) to (8) in FIG. 14. In addition, in this example of this embodiment, as in the conventional example, the evaluation image (patch) was a 4 cm x 4 cm solid image. The color ink adhesion amount of each patch was the value shown in FIG. 14, and the white ink adhesion amount as the background was the same value for each patch, and was the value shown in FIG. 14. Patch (8) was a white image as a reference example. Therefore, the color ink adhesion amount was set to 0.

[0072] In this example, for the patches (3) Ye, (5) Red, and (6) Green, where color unevenness occurred in the conventional example, treatment liquid was ejected between the ejection of color ink and the ejection of white ink. In this example, the amount of treatment liquid applied was 7.9 × 10 -5 cc / cm 2 The results of this example, shown in Figure 15, show that no mixing of color ink and white ink occurred in any of the patches. In Figure 15, it was possible to prevent mixing of color ink and white ink in all of the images for transfer formed on the film (No. 2), the image after powder application (No. 3), and the image after transfer (No. 4). As a result, it was possible to form good images on the recording medium.

[0073] In this example, the total amount of ink adhesion is focused on at the boundary between patches where color unevenness occurs and patches where color unevenness does not occur in the conventional example, a threshold value for the total amount of ink adhesion is set, and processing liquid is ejected when the threshold value is exceeded. By ejecting processing liquid on patches where the total amount of ink adhesion was excessive (for example, patches (3) Ye, (5) Red, and (6) Green in the conventional example), color mixing between color inks and white ink can be suppressed, and color unevenness due to color mixing can be suppressed. Furthermore, there is no need to reduce the amount of ink adhesion to suppress color mixing between color inks and white ink, and because the amounts of color inks and white ink adhesion remain the same, the color gamut and size can be maintained.

[0074] From the above study, it was found that if the total amount of ink adhesion is excessive, then the treatment liquid should be ejected. Whether the total amount of ink adhesion is excessive is determined for each predetermined area. In this way, it is possible to make a uniform determination without distinguishing between colors.

[0075] The method for determining the predetermined threshold value can be selected as appropriate. In the results of Figures 13 and 14, no color mixing of color ink and white ink occurred in any patch other than (3) Ye, (5) Red, and (6) Green. Therefore, for example, the total ink adhesion amount of the (4) K patch, which has the largest total ink adhesion amount among the patches where no color mixing occurred, can be used. The total ink adhesion amount of the (4) K patch is 1.7 x 10 -3 cc / cm 2 and white ink deposition amount 2.4 x 10 -3 cc / cm 2 The total value is 4.1 × 10 -3 cc / cm 2 Therefore, the predetermined threshold value for the total amount of ink adhesion is, for example, 4.1×10 -3 cc / cm 2 Set.

[0076] Next, another example of determining the predetermined threshold value for the total ink deposition amount will be described. In this example, the predetermined threshold value is determined using the first test chart below.

[0077] The predetermined threshold value to be compared with the total amount of the deposited color ink and the white ink is determined by the first determination method described below based on the first test chart described below, and the control unit controls the ejection of the treatment liquid using the predetermined threshold value determined by the determination method described below. [First test chart] The amount of the white ink adhered is kept constant, and the amount of the color ink adhered is changed in stages, and the color ink and the white ink are ejected onto the transfer substrate in this order to create multiple test patches, which are used as a first test chart. [First identification method] In the first test chart, it is determined by any judgment method whether or not mixing of the color ink and the white ink has occurred, the boundary between the test patch where mixing occurs and the test patch where mixing does not occur is found, and the total amount of adhesion at the boundary is set to the predetermined threshold value.

[0078] The first test chart is a test chart in which the amount of white ink applied is constant and the amount of color ink applied is varied (changed) in stages. From the perspective of preventing the influence of the color of the recording medium 63, it is preferable that the white ink be ejected only in the area where an image is to be formed. Therefore, the amount of white ink applied to the entire area where an image is to be formed is set to a constant value. In this state, a test chart is created in which the amount of color ink applied is varied in stages, and by performing the first determination method described above, it is possible to determine the total amount of ink applied that is the dividing line between whether or not mixing of color ink and white ink occurs on the transfer substrate.

[0079] The method for determining whether or not color ink and white ink are mixed in the first test chart (any of the above-mentioned determination methods) is not particularly limited and can be selected as appropriate. For example, the determination may be made visually, or by measuring color unevenness using any measurement device. The first test chart has multiple test patches. The first test chart may have an image such as No. 2 in FIG. 13, but any of the states of Nos. 2 to 4 in FIG. 13 may be determined visually or by measuring color unevenness using a measurement device, so all patterns such as No. 3 and No. 4 can be used.

[0080] According to this example, it is possible to optimize the threshold value used to determine whether or not to eject the treatment liquid, thereby improving the accuracy of the determination. In this example, it is possible to use the treatment liquid more efficiently and to further suppress color unevenness caused by mixing of color ink and white ink.

[0081] Next, an example of determining the amount of treatment liquid adhered will be described. In this example, the amount of treatment liquid adhered is determined using the second test chart below.

[0082] The control unit controls the ejection of the treatment liquid based on the amount of the treatment liquid adhered, which is determined by the second determination method described below using the second test chart described below. [Second test chart] The amount of the color ink and the amount of the white ink adhered are kept constant, and the amount of the treatment liquid adhered is changed in stages, and the color ink, the treatment liquid, and the white ink are ejected onto the transfer substrate in this order to create multiple test patches, which are used as a second test chart. [Second identification method] In the second test chart, it is determined by any determination method whether or not mixing of the color ink and the white ink occurs, and the boundary between the test patch where mixing occurs and the test patch where mixing does not occur is found, and the amount of treatment liquid applied at the boundary is taken as the amount of treatment liquid applied during image formation. The term "image formation" used here refers to the time when the treatment liquid is ejected when an image to be transferred is formed on the transfer substrate.

[0083] The second test chart is a test chart in which the amount of treatment liquid applied is varied (changed) in stages while the amount of color ink and white ink applied is kept constant. By creating test patches with varying amounts of treatment liquid applied in stages, it is possible to identify the amount of treatment liquid applied that is the dividing line between whether or not mixing of color ink and white ink occurs on the transfer substrate when the treatment liquid is used.

[0084] The method for determining whether or not the color ink and the white ink are mixed in the second test chart (any of the above-mentioned determination methods) is not particularly limited and can be selected appropriately. For example, the determination may be made visually, or the determination may be made by measuring color unevenness using any measuring device.

[0085] According to this example, it is possible to determine the amount of treatment liquid to be applied that can prevent the color ink and white ink from mixing, allowing the treatment liquid to be used more efficiently and further suppressing color unevenness caused by the mixing of color ink and white ink.

[0086] The total amount of applied color ink and white ink when creating the second test chart (total amount of applied ink) is set to be greater than the threshold value used to determine whether or not to eject the treatment liquid. In the second test chart, the total amount of applied ink is set to a value that would cause a mixture of color ink and white ink if the treatment liquid were not ejected, and each test patch is created by varying the amount of applied treatment liquid in stages.

[0087] 16 is a diagram showing an example of a second test chart. In this example, the second test chart uses red as the color ink, and test patches (also referred to as patches) are prepared by gradually varying the amount of treatment liquid applied. (A) is the second test chart, showing the state after a test patch is prepared on a transfer substrate and an image for transfer is formed. (B) shows the state after the image for transfer of (A) has been transferred to a recording medium.

[0088] The amount of treatment liquid applied is 0 cc / cm from left to right on the paper. 2 , 4.1×10 -5 cc / cm 2 , 7.9×10 -5 cc / cm 2 , 1.2 × 10 -4 cc / cm 2 , 1.6×10 -4 cc / cm 2 , 2.0×10 -4 cc / cm 2 It states that: The amounts of color ink and white ink applied are the same for all test patches. In this example, the values ​​shown in (5) of FIG.

[0089] In the patch on the far left of Figures 16(A) and (B) (1 in the figure), no treatment liquid is ejected, resulting in a mixture of color ink and white ink, causing color unevenness. Looking at Figure 16(A), a mixture of color ink and white ink can also be visually confirmed in the second patch from the left (2 in the figure). When visually confirmed, no mixture of color ink and white ink has occurred in the third patch from the left (3 in the figure), so it can be determined that the amount of treatment liquid applied to the third to sixth patches from the left is appropriate. This corresponds to the second identification method described above.

[0090] In this example, the treatment liquid is ejected at the amount of treatment liquid applied to the third to sixth patches from the left to form an image for transfer. Note that the amount of treatment liquid applied to each patch is not limited to the amount of treatment liquid applied to each patch, and any amount of treatment liquid applied can be selected as appropriate within the range of the amounts of treatment liquid applied to the third to sixth patches. For example, the amount may be a value between the third and fourth amounts of treatment liquid applied.

[0091] From the perspective of preventing the mixing of color inks and white ink, even when using the second test chart of this example, it is acceptable to eject treatment liquid in an amount that exceeds the amount of treatment liquid applied to the sixth patch. On the other hand, if the treatment liquid is excessive, streaks may appear in the image when the image to be transferred is formed on the transfer substrate. If streaks appear in the image, the image quality after transfer may be reduced.

[0092] FIG. 17 is a diagram showing an example of an excess of treatment liquid, showing an image to be transferred formed on a transfer substrate. In the example shown, there is an excess of treatment liquid, causing streaks in the image to be transferred. In the example shown, the amount of treatment liquid attached is 1.0×10 -3 cc / cm 2 It is thought that the white ink is pulled by the treatment liquid, resulting in areas where no white ink is attached, which appear as streaks.

[0093] By optimizing the amount of treatment liquid applied, it is possible to prevent insufficient or excessive ejection of treatment liquid while suppressing color unevenness caused by the mixing of color ink and white ink. Furthermore, by using the second test chart, it is possible to select not only an amount of treatment liquid applied that can suppress the mixing of color ink and white ink, but also an amount of treatment liquid applied that can prevent streaks caused by excessive ejection of treatment liquid.

[0094] Next, another example of a method for determining the amount of treatment liquid applied will be described. In this example, the amount of treatment liquid to be applied is determined based on the ratio of the amount of treatment liquid to the total amount of ink to be applied (the total amount of color ink and white ink to be applied). In this example, the control unit controls the ejection of the treatment liquid so that the amount of the treatment liquid adhered in the area where the treatment liquid is ejected is 1 / 1000 to 1 / 10 of the total amount of the color ink adhered and the white ink adhered. By optimizing the amount of treatment liquid applied in this way, it is possible to prevent insufficient or excessive discharge of treatment liquid, while also suppressing color unevenness caused by the mixing of color ink and white ink.

[0095] FIG. 18 is a diagram showing an example of a case where the amount of treatment liquid applied in this example is determined. In the illustrated example, the amount of treatment liquid applied is specified when treatment liquid is used in (3) Ye, (5) Red, and (6) Green, where a mixture of color ink and white ink occurs, in the conventional example shown in Figure 14 above. The ratio of the amount of applied treatment liquid (B in the figure) to the total amount of ink applied (total amount of applied color ink and white ink, A in the figure). The amount of applied treatment liquid is determined so that the ratio of the amount of applied treatment liquid is 1 / 1000 to 1 / 10. As shown as B, the amount of applied treatment liquid in this example is 7.9 x 10 -5 cc / cm 2 It was decided.

[0096] When the treatment liquid was ejected at this deposition amount, the image to be transferred onto the transfer substrate was prevented from mixing with the color ink and the white ink. Furthermore, the image to be transferred onto the transfer substrate was free of streaks. Furthermore, when the image was transferred onto the printing substrate, no color unevenness occurred. Therefore, according to this example, color unevenness due to the mixing of the color ink and the white ink can be suppressed while preventing insufficient or excessive ejection of the treatment liquid. Furthermore, this example eliminates the need to create a test chart and evaluate the test chart.

[0097] Next, a mode of ejecting treatment liquid onto an image formation area that has been determined as a target for ejecting treatment liquid will be described.

[0098] In S30 of the flow shown in FIG. 10, the position where the treatment liquid is to be deposited (landed) from the liquid ejection head onto the nth image formation region is determined. When depositing treatment liquid from the liquid ejection head onto the nth image formation region, the landing position can be selected as appropriate. For example, the image formation region can be divided into pixels, which are the units onto which droplets of treatment liquid are to be deposited, and the pixels onto which the treatment liquid is to be deposited can be selected. In this case, the treatment liquid can be deposited onto all pixels in the image formation region, but depending on the size of the treatment liquid droplets, excessive treatment liquid may be applied. If a location where the treatment liquid is particularly concentrated occurs, white ink is likely to aggregate in that location, which may result in uneven application of the white ink. Therefore, it is important to select the pixels onto which the treatment liquid is to be deposited within the image formation region and the size of the treatment liquid droplets.

[0099] Therefore, in this example, the size of the droplets (which may also be referred to as droplet size, liquid drop size, etc.) is defined, and pixels onto which the treatment liquid is to be discharged are selected at random so that the pixels onto which the treatment liquid is to be landed in the image formation area do not overlap. In other words, in this example, the control unit sets the droplet size of the treatment liquid to 12 pL or less, divides the area to which the treatment liquid is to be ejected based on a threshold value judgment into pixels, which are the units onto which the droplets of the treatment liquid will land, randomly selects pixels so that the pixels onto which the droplets of the treatment liquid will land do not overlap, and ejects the treatment liquid onto the selected pixels. By doing this, it is possible to prevent the treatment liquid from becoming thicker in certain areas, suppress uneven application of white ink, and make it less likely that color unevenness will occur. If treatment liquid is applied to all pixels, the amount of treatment liquid may be excessive, which could result in abnormal images such as streaks. Therefore, as in this example, by dividing the image formation area into smaller pixel units and thinning out the pixels before applying treatment liquid, it is possible to prevent the amount of treatment liquid from becoming excessive.

[0100] FIG. 19 is a diagram for explaining this example. 11A shows an example in which pixels are randomly selected in an image formation area 81 (the area when the entire image formation area 80 in FIG. 11 is set to N pixels) and the droplet size is set to 12 pL. In the figure, the image formation area 81 is divided into 10 x 10 pixels, i.e., 100 pixels, and the pixels are represented by the reference numeral 82. Treatment liquid is ejected onto the randomly selected pixels 82, and the pixels to which the treatment liquid is ejected are represented by black circles. (B) is an example of a case where pixels are randomly selected as in (A), but the droplet size is set to 3 pL.

[0101] In both (A) and (B), the droplet size is set to 12 pL or less, pixels are selected at random so that the pixels onto which the treatment liquid droplets land do not overlap, and the treatment liquid is ejected onto the selected pixels. This suppresses uneven application of white ink and prevents color unevenness.

[0102] In this example, it is also preferable to adjust the pixel coverage rate according to the droplet size. The pixel coverage rate is the ratio between the total number of pixels in the image formation area 81 as the denominator and the number of pixels onto which the treatment liquid is to land as the numerator. The pixel coverage rate for (A) is 6% (6 out of 100 pixels), and the pixel coverage rate for (B) is 24% (24 out of 100 pixels). In (A), the droplet size is relatively large at 12 pL, so the pixel coverage rate is adjusted low to 6%. On the other hand, in (B), the droplet size is relatively small at 3 pL, so the pixel coverage rate is adjusted high to 24%. This makes it possible to further prevent the treatment liquid from becoming thicker in certain areas, making it less likely that color unevenness will occur.

[0103] Next, an example of the operation of discharging the treatment liquid will be described. When there are both regions where the treatment liquid is ejected and regions where the treatment liquid is not ejected, it is preferable to skip (not scan) the treatment liquid carriage in the regions where the treatment liquid is not ejected.

[0104] The liquid ejection device of this example has a treatment liquid carriage equipped with a third ejection means, and the treatment liquid carriage ejects the treatment liquid while scanning, and the control unit scans the treatment liquid carriage over areas where there is an area to eject the treatment liquid, and does not scan the treatment liquid carriage over areas where there is no area to eject the treatment liquid. According to this example, by skipping the scan of the treatment liquid carriage, unnecessary scans can be eliminated, and productivity can be improved.

[0105] 20 is a schematic diagram for explaining this example. (A) is a diagram illustrating the state in which the treatment liquid is discharged onto the film 61. (B) is a diagram illustrating the state after some time has passed since (A). The white arrows in the diagram indicate the transport direction of the film 61 (transfer substrate). The left-right direction on the paper surface is the main scanning direction, which is the scanning direction of the carriage. The up-down direction on the paper surface is the sub-scanning direction, which also corresponds to the transport direction of the film 61.

[0106] The film 61 is placed on a stage 3 (which may also be called a platen) and transported. The treatment liquid carriage in this example is carriage 10B, which is equipped with a third ejection means for ejecting treatment liquid. Carriage 10B ejects treatment liquid onto film 61 while scanning back and forth in the main scanning direction over film 61 along guide rod 11. The black arrow in the figure schematically indicates the direction of movement of carriage 10B.

[0107] On the film 61, there are regions 83a and 83b onto which the treatment liquid is ejected, and regions 84a and 84b onto which the treatment liquid is not ejected. When the regions 83a and 83b are not distinguished from each other, they are referred to as region 83, and when the regions 84a and 84b are not distinguished from each other, they are referred to as region 84. In this example, color ink and white ink are ejected onto both regions 83 and 84.

[0108] As shown in (A), in an area 83a where the treatment liquid is to be ejected, the control unit causes the carriage 10B to scan and eject the treatment liquid onto the area 83a. On the other hand, in an area 84a where the treatment liquid is not to be ejected, the control unit skips the scanning of the carriage 10B and does not cause the carriage 10B to scan. This is indicated by the black arrow in the figure. That is, in the area 83a where the treatment liquid is to be ejected, the black arrow is displayed and the carriage 10B is scanning. On the other hand, in an area 84a where the treatment liquid is not to be ejected, the black arrow is not displayed and the scanning of the carriage 10B is skipped (not scanned).

[0109] As shown in (B), in region 83b where treatment liquid is to be ejected, the control unit causes carriage 10B to scan and eject treatment liquid onto region 83b. As shown in the figure, the black arrows are long arrows corresponding to region 83b, and the control unit causes carriage 10B to scan corresponding to region 83b. On the other hand, in region 84b where treatment liquid is not to be ejected, carriage 10B does not scan.

[0110] In this way, in (A), scanning of carriage 10B is performed only in area 83a, and scanning of carriage 10B can be skipped in area 84a. Similarly, in (B), scanning of carriage 10B is performed only in area 83b, and scanning of carriage 10B can be skipped in area 84b. This makes it possible to eliminate unnecessary scanning and improve productivity.

[0111] Next, another example of the operation of discharging the treatment liquid will be described. In this example, the color ink and the treatment liquid are ejected in parallel, or the white ink and the treatment liquid are ejected in parallel. The phrase "ejecting in parallel" may also be referred to as "ejecting simultaneously."

[0112] The liquid ejection device of this example has an ink carriage equipped with the first ejection means and the second ejection means, a treatment liquid carriage equipped with the third ejection means, and a transport means for transporting the transfer substrate, the transport means being capable of transporting the transfer substrate in an outward and return path, the ink carriage and the treatment liquid carriage scanning back and forth in a direction perpendicular to the transport direction of the transfer substrate, and the control unit scanning the ink carriage and the treatment liquid carriage on the outward or return path of the transfer substrate to eject the color ink and the treatment liquid in parallel, or to eject the white ink and the treatment liquid in parallel. According to this example, productivity can be improved.

[0113] 21 is a schematic cross-sectional view for explaining this example. (A) is an example in which color ink and treatment liquid are ejected in parallel on the forward pass. (B) is an example in which white ink and treatment liquid are ejected in parallel on the return pass.

[0114] The film 61 is placed on a stage 3 (which may also be called a platen) and transported. The white arrow in the figure indicates the transport direction of the film 61. The transport direction of the film 61 also corresponds to the sub-scanning direction. The ink carriage in this example is carriage 10A, which is equipped with a first ejection means that ejects color inks and a second ejection means that ejects white ink. The treatment liquid carriage in this example is carriage 10B, which is equipped with a third ejection means that ejects treatment liquid.

[0115] In the example shown in (A), the carriage 10A is scanned while the film 61 is being transported in the forward direction, and color ink is ejected onto the film 61. When the film 61 reaches the ejection position for the treatment liquid during the operation of ejecting the color ink, not only is the carriage 10A scanned, but the carriage 10B is also scanned. In other words, the carriages 10A and 10B are scanned in parallel. The control unit in this example scans the carriages 10A and 10B on the forward direction of the film 61, and ejects the color ink and the treatment liquid in parallel. This allows the treatment liquid to be ejected efficiently.

[0116] In the example shown in (B), carriage 10B is scanned while film 61 is being transported in the return path, and treatment liquid is ejected onto film 61. When film 61 reaches the white ink ejection position during the operation of ejecting treatment liquid, not only carriage 10B is scanned, but carriage 10A is also scanned. In other words, carriages 10A and 10B are scanned in parallel. The control unit in this example scans carriages 10A and 10B on the return path of film 61, ejecting white ink and treatment liquid in parallel. This allows treatment liquid to be ejected efficiently.

[0117] For example, aspects of the present invention are as follows. <1> a first ejection means for ejecting color ink onto a transfer substrate for transferring an image onto a printing substrate; a second ejection means for ejecting white ink onto the transfer substrate, the white ink serving as a base for the color inks when the image is transferred to the printing substrate; a third ejection means for ejecting a treatment liquid containing a flocculant onto the transfer substrate; a control unit that controls the ejection of the color inks, the white ink, and the treatment liquid, The control unit calculates the total amount of the color ink and the white ink attached for each predetermined area based on image data, and controls the ejection of the treatment liquid onto an area where the total amount of the color ink and the white ink attached exceeds a predetermined threshold. A liquid ejection device characterized by: <2> When the control unit ejects the treatment liquid onto an area where the total amount of the color inks and the white ink exceeds a predetermined threshold, the control unit controls the ejection onto the transfer substrate in the order of the color inks, the treatment liquid, and the white ink. Characterized by <1> The liquid ejection device according to claim 1. <3> The amount of white ink adhered is determined by the following method for specifying the amount of white ink adhered: The control unit controls the ejection of the white ink in an amount determined by the following method for specifying the amount of white ink adhesion: Characterized by <1> or <2> The liquid ejection device according to claim 1. [How to determine the amount of white ink attached] The white ink is ejected onto the transfer substrate in an arbitrary amount of adhesion to form an image for specifying the amount of adhesion, the image for determining the amount of adhesion is transferred to the printed material, and an adhesion amount that is not affected by the color of the printed material is specified using an arbitrary judgment method. <4> The predetermined threshold value to be compared with the total amount of the color ink and the white ink is determined by the first determination method described below based on the first test chart described below, The control unit controls the ejection of the treatment liquid using a predetermined threshold value determined by the following specification method: Characterized by <1> from <3> 10. The liquid ejection device according to claim 9, wherein [First test chart] The amount of the white ink adhered is kept constant, and the amount of the color ink adhered is changed in stages, and the color ink and the white ink are ejected onto the transfer substrate in this order to create multiple test patches, which are used as a first test chart. [First identification method] In the first test chart, it is determined by any judgment method whether or not mixing of the color ink and the white ink has occurred, the boundary between the test patch where mixing occurs and the test patch where mixing does not occur is found, and the total amount of adhesion at the boundary is set to the predetermined threshold value. <5> The control unit controls the ejection of the treatment liquid based on the amount of the treatment liquid adhered, which is determined by a second determination method described below using a second test chart described below. Characterized by <1> from <3> 10. The liquid ejection device according to claim 9, wherein [Second test chart] The amount of the color ink and the amount of the white ink adhered are kept constant, and the amount of the treatment liquid adhered is changed in stages, and the color ink, the treatment liquid, and the white ink are ejected onto the transfer substrate in this order to create multiple test patches, which are used as a second test chart. [Second identification method] In the second test chart, it is determined by any determination method whether or not mixing of the color ink and the white ink occurs, and the boundary between the test patch where mixing occurs and the test patch where mixing does not occur is found, and the amount of treatment liquid applied at the boundary is taken as the amount of treatment liquid applied during image formation. <6> The control unit controls the ejection of the treatment liquid in the region where the treatment liquid is ejected so that the amount of the treatment liquid applied is 1 / 1000 to 1 / 10 of the total amount of the color ink applied and the white ink applied. Characterized by <1> from <5> 10. The liquid ejection device according to claim 9, wherein <7> The control unit sets the droplet size of the treatment liquid to 12 pL or less, divides the area to which the treatment liquid is to be ejected based on the threshold value into pixels, which are units onto which the droplets of the treatment liquid land, randomly selects pixels so that the pixels onto which the droplets of the treatment liquid land do not overlap, and ejects the treatment liquid onto the selected pixels. Characterized by <1> from <6> 10. The liquid ejection device according to claim 9, wherein <8> a treatment liquid carriage on which the third discharge means is mounted, the treatment liquid carriage ejects the treatment liquid while scanning; The control unit causes the treatment liquid carriage to scan over a location where there is an area onto which the treatment liquid is to be ejected, and does not cause the treatment liquid carriage to scan over a location where there is no area onto which the treatment liquid is to be ejected. Characterized by <1> from <7> 10. The liquid ejection device according to claim 9, wherein <9> an ink carriage on which the first ejection means and the second ejection means are mounted; a treatment liquid carriage on which the third discharge means is mounted; and a conveying means for conveying the transfer substrate, the transport means is capable of transporting the transfer substrate in a forward direction and a backward direction, the ink carriage and the treatment liquid carriage perform reciprocating scanning in a direction perpendicular to a transport direction of the transfer substrate; The control unit scans the ink carriage and the treatment liquid carriage on the outward or return path of the transfer substrate, and ejects the color ink and the treatment liquid in parallel, or ejects the white ink and the treatment liquid in parallel. Characterized by <1> from <8> 10. The liquid ejection device according to claim 9, wherein <10> a first ejection step of ejecting color ink onto a transfer substrate that transfers an image onto a printing substrate; a second ejection step of ejecting onto the transfer substrate a white ink that will serve as a base for the color inks when the image is transferred to the printing substrate; a third ejection step of ejecting a treatment liquid containing a flocculant onto the transfer substrate; a control step of controlling the ejection of the color ink, the white ink, and the treatment liquid, The control step calculates a total amount of the color ink and the white ink attached for each predetermined area based on image data, and controls the ejection of the treatment liquid onto an area where the total amount of the color ink and the white ink attached exceeds a predetermined threshold. A liquid ejection method comprising: [Explanation of symbols]

[0118] 1 Liquid discharge device 3 Stages 7 Front cover (cover part) 8 Rear cover (cover part) 9A, 9B Liquid discharge part 10 Carriage 51 color ink 52 White Ink 53 Processing liquid 61 Film (transfer substrate) 62 Powder 63 Recording medium (printed material) 71-73 Liquid ejection head 80 Entire image forming area 81 Image forming area 82 pixels 83 Processing liquid discharge area 84 Area where processing liquid is not discharged [Prior art documents] [Patent documents]

[0119] [Patent Document 1] Japanese Patent Publication No. 2023-087372

Claims

1. a first ejection means for ejecting color ink onto a transfer substrate for transferring an image onto a printing substrate; a second ejection means for ejecting white ink onto the transfer substrate, the white ink serving as a base for the color inks when the image is transferred onto the printing substrate; a third ejection means for ejecting a treatment liquid containing a flocculant onto the transfer substrate; a control unit that controls the ejection of the color inks, the white ink, and the treatment liquid, The control unit calculates the total amount of the color ink and the white ink attached for each predetermined area based on image data, and controls the ejection of the treatment liquid onto an area where the total amount of the color ink and the white ink attached exceeds a predetermined threshold. A liquid ejection device characterized by:

2. When the control unit ejects the treatment liquid onto an area where the total amount of the color inks and the white ink exceeds a predetermined threshold, the control unit controls the ejection onto the transfer substrate in the order of the color inks, the treatment liquid, and the white ink. The liquid ejection device according to claim 1 .

3. The amount of white ink adhered is determined by the following method for specifying the amount of white ink adhered: The control unit controls the ejection of the white ink in an amount determined by the following method for specifying the amount of white ink adhesion: The liquid ejection device according to claim 1 . [Method for determining the amount of white ink attached] The white ink is ejected onto the transfer substrate in an arbitrary amount of adhesion to form an image for specifying the amount of adhesion, the image for determining the amount of adhesion is transferred to the printed material, and an amount of adhesion that is not affected by the color of the printed material is specified using an arbitrary judgment method.

4. The predetermined threshold value to be compared with the total amount of the deposited color ink and the deposited white ink is determined by the following first determination method based on the following first test chart, The control unit controls the ejection of the treatment liquid using a predetermined threshold value determined by the following specification method: The liquid ejection device according to claim 1 . [First Test Chart] The amount of the white ink adhered is kept constant, and the amount of the color ink adhered is changed in stages, and the color ink and the white ink are ejected onto the transfer substrate in this order to prepare multiple test patches, which are used as a first test chart. [First Identification Method] In the first test chart, it is determined by any determination method whether or not mixing of the color ink and the white ink has occurred, the boundary between the test patch where mixing occurs and the test patch where mixing does not occur is found, and the total amount of adhesion at the boundary is set to the predetermined threshold value.

5. The control unit controls the ejection of the treatment liquid based on the amount of the treatment liquid adhered, which is determined by a second determination method described below using a second test chart described below. The liquid ejection device according to claim 1 . [Second Test Chart] The amount of the color ink and the amount of the white ink adhered are kept constant, and the amount of the treatment liquid adhered is changed in stages, and the color ink, the treatment liquid, and the white ink are ejected onto the transfer substrate in this order to create multiple test patches, which are used as a second test chart. [Second Identification Method] In the second test chart, it is determined by any determination method whether or not mixing of the color ink and the white ink occurs, the boundary between the test patch where mixing occurs and the test patch where mixing does not occur is found, and the amount of treatment liquid attached at the boundary is set as the amount of treatment liquid attached during image formation.

6. The control unit controls the ejection of the treatment liquid in the region where the treatment liquid is ejected so that the amount of the treatment liquid applied is 1 / 1000 to 1 / 10 of the total amount of the color ink applied and the white ink applied. The liquid ejection device according to claim 1 .

7. The control unit sets the droplet size of the treatment liquid to 12 pL or less, divides the region to which the treatment liquid is to be ejected based on the threshold value into pixels, which are units onto which the droplets of the treatment liquid land, randomly selects pixels so that the pixels onto which the droplets of the treatment liquid land do not overlap, and ejects the treatment liquid onto the selected pixels. The liquid ejection device according to claim 1 .

8. a treatment liquid carriage on which the third discharge means is mounted, the treatment liquid carriage ejects the treatment liquid while scanning; The control unit causes the treatment liquid carriage to scan over a location where there is an area onto which the treatment liquid is to be ejected, and does not cause the treatment liquid carriage to scan over a location where there is no area onto which the treatment liquid is to be ejected. The liquid ejection device according to claim 1 .

9. an ink carriage on which the first ejection means and the second ejection means are mounted; a treatment liquid carriage on which the third discharge means is mounted; and a conveying means for conveying the transfer substrate, the transport means is capable of transporting the transfer substrate in a forward direction and a backward direction, the ink carriage and the treatment liquid carriage perform reciprocating scanning in a direction perpendicular to a transport direction of the transfer substrate; The control unit scans the ink carriage and the treatment liquid carriage on the outward or return path of the transfer substrate, and ejects the color ink and the treatment liquid in parallel, or ejects the white ink and the treatment liquid in parallel. The liquid ejection device according to claim 1 .

10. a first ejection step of ejecting color ink onto a transfer substrate that transfers an image onto a printing substrate; a second ejection step of ejecting white ink onto the transfer substrate, the white ink serving as a base for the color inks when the image is transferred to the printing substrate; a third ejection step of ejecting a treatment liquid containing a flocculant onto the transfer substrate; a control step of controlling the ejection of the color ink, the white ink, and the treatment liquid, The control step calculates a total amount of the color ink and the white ink attached for each predetermined area based on image data, and controls the ejection of the treatment liquid onto an area where the total amount of the color ink and the white ink attached exceeds a predetermined threshold. A liquid ejection method comprising:

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