Printing method and printing apparatus

Abstract

The invention provides a printing method and a printing apparatus for suppressing bleeding of a transfer image. The printing method includes: an image forming step of performing a first process of forming an image on a transfer medium by discharging colored ink from a first inkjet head; and a substrate forming step of performing a second process including a process of superimposing the substrate ink on the image by discharging the substrate ink from a second inkjet head on the transfer medium, wherein, in the substrate forming step, regions where the adhesive is supplied at the same timing in the adhesive applying step for the transfer medium are set as processing unit regions, and in the substrate forming step, the second processing is delayed from the midway of the second processing to the completion of the second processing for the processing unit regions.

Description

Technical Field

[0001] The present invention relates to a printing method for performing printing on a transfer medium, and a printing apparatus. Background Art

[0002] As disclosed in Patent Document 1, a printing method for cloth using a transfer sheet as a transfer medium is known. The printing method includes a step of printing first image data on a transfer sheet using black toner and color toner, a step of processing all colors in the printing range of the first image data into black to produce second image data, a step of printing the second image data on the transfer sheet on which the first image data is printed using white toner instead of black toner, a step of applying an adhesive on the uppermost layer of the printed transfer sheet, a step of bonding the transfer sheet coated with the adhesive to the cloth and pressing while heating, and a step of peeling the base material of the transfer sheet.

[0003] In the case of forming an image to be transferred onto cloth as a transfer medium using an inkjet printer, it is considered to attach a powdery hot-melt adhesive to the image formed by the ink sprayed onto the transfer sheet and transfer the image onto the cloth. For example, by forming an image of colored ink on the transfer sheet, overlapping white ink on the image, attaching the powdery hot-melt adhesive to the white ink, and attaching the heated hot-melt adhesive to the cloth, the image on the transfer sheet can be transferred onto the cloth.

[0004] When white ink is sprayed onto the image on the transfer sheet, it gradually dries. In the printed area on the transfer sheet, the later the white ink is sprayed, the less the drying degree of the white ink. Therefore, when the transfer sheet is tilted to apply the powdery hot-melt adhesive or the like, the white ink with a smaller drying degree sometimes flows downward. If the white ink flows downward, bleeding occurs on the transferred image.

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2014-104595 Summary of the Invention

[0006] The printing method of the present invention has the following mode. That is, in order to perform an adhesive application step and a transfer step to perform printing on a transfer medium, the adhesive application step is a step of attaching an adhesive to a base ink, the base ink being overlapped on an image formed on the transfer medium, and the transfer step is a step of transferring the image onto the transfer medium by attaching the adhesive to the transfer medium. Among them,

[0007] The printing method includes:

[0008] An image forming step that performs a first process of forming the image on the transfer medium by ejecting a colored ink from a first inkjet head;

[0009] A substrate forming step that performs a second process including a process of overlapping the substrate ink on the image by ejecting the substrate ink from a second inkjet head onto the transfer medium,

[0010] A region where the adhesive is supplied to the transfer medium at the same timing in the adhesive application step is set as a processing unit region,

[0011] In the substrate forming step, the second process is delayed from the middle of the second process for the processing unit region until the completion of the second process.

[0012] In addition, the printing apparatus of the present invention has the following mode, that is, in order to perform the adhesive application step and the transfer step to perform printing on the transfer medium, the adhesive application step is a step of attaching the adhesive to the substrate ink, the substrate ink is overlapped on the image formed on the transfer medium, and the transfer step is a step of transferring the image to the transfer medium by attaching the adhesive to the transfer medium, wherein,

[0013] The printing apparatus includes:

[0014] A first inkjet head that ejects a colored ink;

[0015] A second inkjet head that ejects the substrate ink;

[0016] A drive unit that relatively moves the second inkjet head in a first direction with respect to the transfer medium;

[0017] A control unit that controls the ejection of the colored ink from the first inkjet head, the ejection of the substrate ink from the second inkjet head, and the drive unit,

[0018] The control unit performs the following control, that is:

[0019] Controls a first process of forming the image on the transfer medium by ejecting the colored ink from the first inkjet head,

[0020] Controls a second process including a process of overlapping the substrate ink on the image by ejecting the substrate ink from the second inkjet head with respect to the transfer medium,

[0021] A region in which the adhesive is supplied at the same timing in the adhesive application step for the transfer medium is set as a processing unit region.

[0022] The control unit performs control to delay the second process from the middle of the second process for the processing unit region until the completion of the second process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A diagram schematically showing a structural example of a printing system.

[0024] Figure 2 A top view schematically showing a structural example of a printer.

[0025] Figure 3 A bottom view schematically showing an example of a nozzle surface of an inkjet head.

[0026] Figure 4 A block diagram schematically showing a structural example of a printing apparatus.

[0027] Figure 5 A diagram schematically showing an example of a printing method for a transfer medium.

[0028] Figure 6 A diagram schematically showing an example of area division of a processing unit region.

[0029] Figure 7 A diagram schematically showing an example of side shift intermittent conveyance.

[0030] Figure 8 A diagram schematically showing an example of a processing unit region in a single sheet of paper.

[0031] Figure 9 A flowchart schematically showing an example of a printing control process.

[0032] Figure 10 A diagram schematically showing an example of determining the presence or absence of a continuous region exceeding a reference area.

[0033] Figure 11 A flowchart schematically showing another structural example of a cycle number table and another example of a printing control process.

[0034] Figure 12 A diagram schematically showing an example of changing the cycle number according to the base ink ejection amount per unit area. DETAILED DESCRIPTION OF THE INVENTION

[0035] Hereinafter, embodiments of the present invention will be described. Of course, the following embodiments are merely examples of the present invention, and not all the features shown in the embodiments are necessarily required for the solution of the invention.

[0036] (1) Outline of the embodiments included in the present invention:

[0037] First, refer to Figures 1 to 12 the example shown to describe the outline of the embodiments included in the present invention. In addition, the drawings of the present application are diagrams schematically showing examples, and sometimes the scales of the respective parts are different from the actual situation in order to make the respective parts of these drawings recognizable, and the magnification ratios in the respective directions shown in these drawings are sometimes different, so there are cases where the respective drawings do not match. Of course, the respective elements of this embodiment are not limited to the specific examples indicated by the symbols. In the "outline of the embodiments included in the present invention", the content in parentheses refers to the supplementary explanation of the immediately preceding term.

[0038] In addition, in the present application, the numerical range "Min~Max" means equal to or greater than the minimum value Min and equal to or less than the maximum value Max.

[0039] Embodiment 1

[0040] As exemplified by Figure 1 、 5 etc., a printing method according to one embodiment is a printing method for performing printing on the transfer medium M1 by carrying out an adhesive application step ST3 of applying an adhesive 111 onto a base ink 36b that is overlapped on an image IM1 formed on the transfer medium M1, and a transfer step ST5 of transferring the image IM1 onto the transfer medium M2 by attaching the adhesive 111 to the transfer medium M2. This printing method includes the following steps.

[0041] (a1) An image forming step ST1 of performing a first process, which is a process of forming the image IM1 on the transfer medium M1 by ejecting a colored ink 36a from a first inkjet head (for example, a colored ink head 31).

[0042] (a2) A base forming step ST2 of performing a second process, which includes a process of relatively moving a second inkjet head (for example, a base ink head 32) relative to the transfer medium M1 in a first direction D1, and a process of overlapping the base ink 36b on the image IM1 by ejecting the base ink 36b from the second inkjet head (32).

[0043] Here, as Figure 2 、 6As exemplified above, the area where the adhesive 111 is supplied to the transfer medium M1 at the same timing in the adhesive application step ST3 is set as the processing unit area A0. In the substrate formation step ST2, the second processing is delayed from the middle of the second processing for the processing unit area A0 until the completion of the second processing.

[0044] By delaying the second processing from the middle of the second processing for the above-mentioned processing unit area A0 until the completion of the second processing, the drying of the base ink 36b at the portion where the base ink 36b is finally overlapped on the image IM1 in the processing unit area A0 is promoted. Thereby, the flow of the base ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3 can be suppressed, and thus the bleeding of the transferred image (the transferred image IM1) caused by the downward flow of the base ink 36b or the like can be suppressed. Therefore, the above method can provide a printing method capable of suppressing the bleeding of the transferred image.

[0045] In the above method, various examples are considered.

[0046] The relative movement of the second inkjet head (32) relative to the transfer medium M1 in the first direction D1 includes the case where the second inkjet head (32) moves in the first direction D1 under the condition that the transfer medium M1 does not move, the case where the transfer medium M1 moves in the direction opposite to the first direction D1 under the condition that the second inkjet head (32) does not move, and the case where both the transfer medium M1 and the second inkjet head (32) move along the first direction D1. In addition, the second inkjet head (32) may also perform relative movement relative to the transfer medium M1 in the second direction D2 intersecting the first direction D1.

[0047] The first inkjet head (31) may perform relative movement relative to the transfer medium M1 together with the second inkjet head (32), or may perform relative movement relative to the transfer medium M1 independently of the second inkjet head (32).

[0048] In the processing unit area A0, the following areas are included.

[0049] (Area b1) An area corresponding to the amount of a single sheet of paper in the case where the transfer medium is a single sheet of paper (for example, refer to Figure 8 ).

[0050] (Area b2) An area corresponding to the amount of one-time conveyance in the case where the transfer medium, which is a continuous paper subjected to side-shift printing, is intermittently conveyed (for example, refer to Figure 7 ).

[0051] An area (area b3) corresponding to the conveyance amount of one sub-scan amount in the case of performing sub-scanning for a transfer medium on which serial printing is performed.

[0052] An area (area b4) corresponding to the amount of one cut transfer medium in the case where a transfer medium on which line printing is performed is cut.

[0053] In addition, printing on a single sheet of paper can be any one of side shift type, serial type, and line type. The side shift type is a printing method in which an inkjet head ejects ink while scanning in the main scanning direction and in a sub-scanning direction intersecting the main scanning direction with respect to a processing unit area of the transfer medium. The side shift type for continuous paper is a printing method in which the inkjet head ejects ink while scanning in the conveying direction and in a direction intersecting the conveying direction with respect to the above-mentioned area b2 of the transfer medium in a conveyance stop state, and intermittently conveys the continuous paper in the conveying direction in units corresponding to the above-mentioned area b2. The serial type is a printing method in which the inkjet head ejects ink while reciprocating in the main scanning direction and performs sub-scanning during the main scanning. The line type is a printing method in which ink is ejected from an inkjet head having a length greater than the width of the continuous paper onto the continuous paper being conveyed. The materials of the single sheet of paper and the continuous paper are not limited to strict paper, and can also be resin, metal, etc.

[0054] In the substrate forming step ST2, the substrate ink 36b can be ejected from the second inkjet head (32) that relatively moves in the first direction D1, or the substrate ink 36b can be ejected from the second inkjet head (32) that relatively moves in the second direction D2 under the condition that the relative position in the first direction D1 does not change.

[0055] The second process can also be a combination of a process of overlapping the substrate ink 36b on the image IM1 while performing main scanning along the second direction D2 and a process of performing sub-scanning in the first direction D1. In addition, the second process can also be a combination of a process of overlapping the substrate ink 36b on the image IM1 while performing main scanning along the first direction D1 and a process of performing sub-scanning in the second direction D2. And the second process can also be a process of overlapping the substrate ink 36b on the image IM1 while conveying the transfer medium M1 in a direction opposite to the first direction D1.

[0056] In the delay of the second process, it includes an increase in the number of cycles NP of the main scanning accompanied by the ejection of the substrate ink 36b, an increase in the processing time of the sub-scanning, an increase in the processing time of the main scanning, etc. that are performed at the same position in the transfer medium M1.

[0057] In this application, terms such as "first", "second",... are used to identify each structural element included in multiple structural elements with similarities, and do not refer to order.

[0058] Of course, the above supplementary explanations also apply in the following manner.

[0059] Mode 2

[0060] As Figure 6 Illustrated, etc., the processing unit area A0 may also include a first area A1 and a second area A2 where the base ink 36b is overlapped on the image IM1 at a later time compared to the first area A1. The second area A2 may also include the portion where the base ink 36b is finally overlapped on the image IM1 in the processing unit area A0. In this printing method, in the base forming step ST2, the second processing for the second area A2 may be delayed.

[0061] The drying time of the base ink 36b in the second area A2 is shorter than that in the first area A1. By delaying the second processing for the second area A2 instead of the processing for the first area A1, the flow of the base ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3 can be suppressed. Therefore, the above mode can suppress the bleeding of the transferred image while minimizing the reduction in productivity.

[0062] The processing unit area A0 may also include a third area A3 where the base ink 36b is overlapped on the image IM1 at a later time compared to the first area A1 and an earlier time compared to the second area A2. In this case, in the base forming step ST2, on the basis of delaying the second processing for the third area A3, the second processing for the second area A2 may be further delayed.

[0063] The above supplementary explanations also apply in the following manner.

[0064] Mode 3

[0065] As Figure 6As exemplified above, in this printing method, the following second treatment may also be performed in the substrate forming step ST2: while the second inkjet head (32) is relatively moved with respect to the transfer medium M1 in a second direction D2 intersecting the first direction D1, the main scan of ejecting the substrate ink 36b is performed, and during the sub-scan during this main scan, the second inkjet head (32) is relatively moved with respect to the transfer medium M1 in the first direction D1, thereby changing the position in the first direction D1 where the substrate ink 36b is overlapped on the image IM1. Here, the number of times of the main scan accompanied by the ejection of the substrate ink 36b performed at the same position in the transfer medium M1 is set as the number of cycles NP. In this printing method, the following second treatment may also be performed in the substrate forming step ST2: that is, the number of cycles NP in the second region A2 is made more than the number of cycles NP in the first region A1.

[0066] When the number of cycles NP increases in the second region A2, the time of the second treatment performed for the second region A2 becomes longer. As a result, the second treatment is delayed from the start time point of the second treatment for the second region A2 to promote the drying of the substrate ink 36b. When the ejection of the substrate ink 36b is divided into NP times of main scans, the ejection amount of the substrate ink 36b for each main scan is less for the second region A2 than for the first region A1, thereby promoting the drying of the substrate ink 36b. When the drying of the substrate ink 36b is promoted, the flow of the substrate ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3 can be suppressed. Therefore, the above method can suppress the bleeding of the transferred image by a simple method of changing the number of cycles for each region.

[0067] Mode 4

[0068] As Figure 10 As exemplified above, the processing unit region A0 may also include a continuous region (for example, the first continuous region A11 or the second continuous region A12) that is connected as the image IM1. In this printing method, in the substrate forming step ST2, in at least one of the first region A1 and the second region A2, when there is a continuous region (A12) exceeding the reference area THS, the number of cycles NP is made more than when there is no continuous region (A12) exceeding the reference area THS.

[0069] The larger the continuous regions (A11, A12) are, the more likely it is for the base ink 36b to flow due to the inclination of the transfer medium M1 in the adhesive application step ST3. When there is a continuous region (A12) with a relatively large area in the first region A1 or the second region A2, the number of cycles NP is made larger compared to the case where there is no continuous region (A12) with a relatively large area, thereby further suppressing the flow of the base ink 36b due to the inclination of the transfer medium M1 in the adhesive application step ST3. Therefore, the above method can further suppress bleeding of the transferred image.

[0070] Mode 5

[0071] As Figure 12 Illustrated, in this printing method, the following second treatment can also be performed in the base forming step ST2: in at least one of the first region A1 and the second region A2, when the ejection amount DT of the base ink 36b per unit area exceeds the first ejection amount THD1, the number of cycles NP is made larger than when the ejection amount DT of the base ink 36b per unit area does not exceed the first ejection amount THD1, and when the ejection amount DT of the base ink 36b per unit area is constant, the number of cycles NP in the second region A2 is made larger than the number of cycles NP in the first region A1.

[0072] The more the ejection amount DT of the base ink 36b per unit area is, the more likely it is for the base ink 36b to flow due to the inclination of the transfer medium M1 in the adhesive application step ST3. Since the drying of the base ink 36b is promoted by increasing the number of cycles NP in the region where the ejection amount DT of the base ink 36b is relatively large, the flow of the base ink 36b due to the inclination of the transfer medium M1 in the adhesive application step ST3 can be further suppressed. When the ejection amount DT of the base ink 36b is constant, by making the number of cycles NP in the second region A2 larger than the number of cycles NP in the first region A1, the second treatment is delayed from the start time point of the second treatment for the second region A2 to promote the drying of the base ink 36b. Therefore, the above method can further suppress bleeding of the transferred image.

[0073] In addition, the ejection amount DT of the base ink 36b per unit area refers to the ratio (including percentage) of the number of dots formed by the ink droplets 37 to a predetermined number of pixels, and in the case of forming dots of different sizes, it refers to the ratio when converted to the largest dots (for example, large dots). A pixel is the smallest element that constitutes an image capable of independently allocating colors. For example, when forming Nd large dots for 100 pixels, the ejection amount DT becomes Nd%.

[0074] The above supplementary description also applies in the following manner.

[0075] Method 6

[0076] The base ink 36b may also be an ink containing a component that shields the transmission of light. In this case, since the color of the transfer medium M2 cannot be observed through the image portion, the quality of the transferred image can be improved.

[0077] Here, among the inks containing a component that shields the transmission of light, there are inks containing a component that diffuses light like white ink, inks containing a component that absorbs light like black ink, inks containing a component that diffuses light and a component that absorbs light like gray ink, and the like. This supplementary description also applies in the following manner.

[0078] Method 7

[0079] In addition, as Figure 1 , 5 illustrated, the printing apparatus 1 according to one aspect is a printing apparatus 1 that performs printing on the transfer medium M1 in order to carry out an adhesive application step ST3 of applying an adhesive 111 onto the base ink 36b on the image IM1 formed on the transfer medium M1, and a transfer step ST5 of transferring the image IM1 onto the transfer medium M2 by attaching the adhesive 111 to the transfer medium M2. As Figures 2 to 4 illustrated, the present printing apparatus 1 includes a first inkjet head (31) that ejects a colored ink 36a, a second inkjet head (32) that ejects the base ink 36b, a drive unit 50, and a control unit 10. The drive unit 50 relatively moves the second inkjet head (32) in a first direction D1 with respect to the transfer medium M1. The control unit 10 controls the ejection of the colored ink 36a from the first inkjet head (31), the ejection of the base ink 36b from the second inkjet head (32), and the drive unit 50. As Figure 5 illustrated, the control unit 10 controls a first process, which is a process of forming the image IM1 on the transfer medium M1 by ejecting the colored ink 36a from the first inkjet head (31). The control unit 10 controls a second process, which includes a process of relatively moving the second inkjet head (32) in the first direction D1 with respect to the transfer medium M1, and a process of overlapping the base ink 36b on the image IM1 by ejecting the base ink 36b from the second inkjet head (32).

[0080] Here, an area where the adhesive 111 is supplied at the same timing in the adhesive application step ST3 with respect to the transfer medium M1 is set as a processing unit area A0. The control unit 10 performs control to delay the second processing from the middle of the second processing for the processing unit area A0 until the completion of the second processing.

[0081] The above-described manner can provide a printing apparatus capable of suppressing bleeding of a transferred image.

[0082] Moreover, the above-described manner can be applied to a printing system including the above-described printing apparatus, a control method of the above-described printing apparatus, a control method of the printing system described above, a control program of the above-described printing apparatus, a control program of the printing system described above, a computer-readable recording medium recording any of the control programs described above, and the like. In addition, the above-described printing apparatus may be constituted by a plurality of dispersed parts.

[0083] (2) Specific example of a printing apparatus:

[0084] Figure 1 Schematically illustrated is the structure of a printing system that forms an image IM1 on a transfer medium M1 and transfers the image IM1 onto a medium to be transferred M2. Figure 1 The illustrated printing system includes a printing apparatus 1, an adhesive application apparatus 100, and a thermal transfer apparatus 200.

[0085] Although the printing apparatus 1 may be a single printer 2, it may also be Figure 1 configured as shown by a printer 2 and a host apparatus HO1. Figure 1 The illustrated host apparatus HO1 can generate image data DA1 corresponding to the image IM1 to be transferred and can transmit the image data DA1 to the printer 2. Hereinafter, the image IM1 to be transferred is also referred to as a transfer image IM1. The printer 2 includes a printing unit 20 that ejects ink onto the transfer medium M1 to form an image IM1 corresponding to the image data DA1. The adhesive application apparatus 100 includes an adhesive tank 110 that causes the adhesive 111 to adhere to the ink on the transfer medium M1, and a heating unit 120 that heats the transfer medium M1 after the adhesive is applied. The thermal transfer apparatus 200 transfers the image IM1 from the transfer medium M1 onto the medium to be transferred M2.

[0086] In the transfer medium M1, a transfer film or the like that can transfer an image by the DTF (Direct to Film) method can be used. In such a transfer film, a resin film such as a PET (polyethylene terephthalate) film can be preferably used. Of course, the material of the transfer medium M1 may include paper, metal, etc. in addition to resin, and the transfer medium M1 may also be a metal film or the like. In the adhesive 111, a powdery adhesive such as a powdery hot-melt adhesive can be used. The hot-melt adhesive is a thermoplastic resin powder, which melts when heated above the melting point and solidifies when cooled. In the hot-melt adhesive, an adhesive containing one or more thermoplastic resins selected from polyurethane resins, polyolefin resins, polyamide resins, polyester resins, etc. can be used. In the medium to be transferred M2, fabrics such as woven or knitted fabrics, non-woven fabrics, etc. can be used, and processed fabrics such as T-shirts can also be used.

[0087] Although it will be described in detail later, in the printing apparatus 1, an image forming step ST1 and a substrate forming step ST2 are carried out. In the adhesive supply apparatus 100, an adhesive supply step ST3 and a heating step ST4 are carried out. In the thermal transfer apparatus 200, a transfer step ST5 is carried out.

[0088] Figure 2 It is a top view schematically illustrating the structure of the printer 2 equipped with the inkjet head 30. In addition, Figure 2 The illustrated processing unit area A0 is a rectangle with a length of L0 and a width of W0. Figure 3 It is a bottom view schematically illustrating the nozzle surface 30a of the inkjet head 30. Figure 4 It is a block diagram schematically illustrating the structure of the printing apparatus 1. Figure 5 It schematically illustrates the printing method for the medium to be transferred M2. Figure 6 It schematically illustrates the area division of the processing unit area A0.

[0089] The printer 2 is an inkjet printer that ejects liquid ink droplets 37. The printer 2 includes a control unit 10, a printing unit 20, a RAM (Random Access Memory) 21 as a semiconductor memory, a communication I / F (interface) 22, a storage unit 23, an operation panel 24, etc. The control unit 10, the RAM 21, the communication I / F 22, the storage unit 23, and the operation panel 24 are connected to the bus and are configured to be able to input and output information to each other. The printing unit 20 includes an inkjet head 30 and a driving unit 50.

[0090] The control unit 10 includes a CPU (Central Processing Unit) 11 as a processor, a color conversion unit 12, a halftone processing unit 13, a rasterization processing unit 14, a drive signal transmission unit 15, and the like. The control unit 10 can be constituted by an SoC (System on a Chip) or the like. Based on the image data DA1 obtained from either the host device HO1 or an external memory (not shown), the control unit 10 controls the inkjet head 30 and the drive unit 50 to form an image IM1 of the colored ink 36a and a layer of the base ink 36b on the transfer medium M1. In the image data DA1, for example, RGB data having integer values of, for example, 2 8 gray levels for R (red), G (green), and B (blue) can be applied to each pixel.

[0091] The CPU 11 is a device that centrally implements information processing and control in the printer 2.

[0092] The color conversion unit 12, for example, has a color conversion LUT (look-up table) that defines the correspondence between the gray levels of R, G, and B and the gray levels of C (cyan), M (magenta), Y (yellow), K (black), and W (white). In the color conversion LUT, the gray level of W is, for example, a value for using the base ink 36b when using at least one of the colored inks 36a of C, M, Y, and K. If an example is given, when the gray levels of C, M, Y, and K are 0 indicating that the colored ink is not used, the gray level of W is 0 indicating that the base ink is not used, and in the remaining cases, the gray level of W is 128 indicating that 50% of the base ink is used. Thus, the base ink 36b is overlapped at the position of the image IM1. Of course, the ejection amount of the base ink 36b overlapped on the image IM1 can be less than 50%, more than 50%, or vary according to the color of the image IM1 within the range where a transfer image IM1 with relatively good image quality can be obtained. The color conversion unit 12 refers to the color conversion LUT and converts the RGB data into ink amount data having integer values of, for example, 2 8 gray levels for C, M, Y, and K in each pixel. The ink amount data represents the usage amounts of the inks 36 of C, M, Y, K, and W in units of pixels. In addition, in Figure 4 the ink 36 shown, there are included colored inks 36a of C, M, Y, and K, and the base ink 36b. Further, when the resolution of the RGB data is different from the printing resolution, the color conversion unit 12 first converts the resolution of the RGB data to the printing resolution or converts the resolution of the ink amount data to the printing resolution.

[0093] The halftone processing unit 13 performs halftone processing on the ink amount data by any method such as dithering or error diffusion, thereby generating dot data with the number of gray levels reduced to, for example, 2 or 4. The dot data is generated separately for C, M, Y, K, and W. The dot data represents the formation state of the dots of the ink 36 in units of pixels.

[0094] The rasterization processing unit 14 performs rasterization processing that rearranges and exchanges the dot data in the order in which the dots are formed by the driving unit 50, thereby generating raster data.

[0095] The drive signal transmission unit 15 generates a drive signal SG1 corresponding to the voltage signal applied to the drive element 42 of the inkjet head 30 from the raster data, and outputs this signal to the drive circuit 41 of the inkjet head 30.

[0096] The RAM 21 stores the image data DA1, etc. received from the host device HO1, etc. The communication I / F 22 inputs and outputs information to and from the host device HO1, etc. Examples of the host device HO1 include computers such as personal computers and tablet terminals, mobile phones such as smartphones, etc. The storage unit 23 can be a non-volatile semiconductor memory such as a flash memory, or a magnetic storage device such as a hard disk, etc. The operation panel 24 includes an output unit 25 such as a liquid crystal panel for displaying information, an input unit 26 such as a touch panel for accepting operations on the display screen, etc.

[0097] The drive circuit 41 applies a voltage signal to the drive element 42 according to the drive signal SG1 input from the drive signal transmission unit 15. The drive element 42 can be a piezoelectric element that applies pressure to the ink 36 in the pressure chamber communicating with the nozzle 34, or a drive element that generates bubbles in the pressure chamber by heat to eject the ink droplets 37 from the nozzle 34, etc. In the pressure chamber of the inkjet head 30, the ink 36 is supplied from the ink cartridge 35. The ink 36 in the pressure chamber is ejected as ink droplets 37 from the nozzle 34 toward the transfer medium M1 through the drive element 42. When the ink droplets 37 fall onto the transfer medium M1, dots are formed on the transfer medium M1. When dots of the colored ink 36a are formed on the transfer medium M1, the image IM1 represented by the pattern of the dots is formed on the transfer medium M1.

[0098] Figure 3The inkjet head 30 shown includes a color ink head 31 that ejects color ink 36a, and a base ink head 32 that ejects base ink 36b. The color ink head 31 is an example of a first inkjet head, and the base ink head 32 is an example of a second inkjet head. The color ink 36a is an ink that contains a color material such as a pigment as a dispersed substance or solute in a liquid (such as water) as a dispersion medium or solvent. In the color ink 36a, for example, there are colored inks containing C, M, and Y, and an ink of K as achromatic color. The color ink head 31 includes a C ink head 31C that ejects C ink, an M ink head 31M that ejects M ink, a Y ink head 31Y that ejects Y ink, and a K ink head 31K that ejects K ink. The base ink 36b is an ink containing a component that shields the transmission of light, for example, a W ink containing a component that diffuses light. The W ink is, for example, an ink that contains a white pigment such as titanium oxide or zinc oxide as a dispersed substance in a liquid such as water as a dispersion medium. By shielding the transmission of light with the base ink 36b, the color of the transfer medium M2 that becomes the background of the image IM1 does not affect the color of the image IM1, and thus a transfer medium M2 with a relatively good image quality can be obtained for the image IM1. Each ink head (31C, 31M, 31Y, 31K, 32) has a nozzle row in which a plurality of nozzles 34 are arranged in a nozzle arrangement direction that intersects the second direction D2 as the scanning direction, for example, the first direction D1. The plurality of nozzles 34 of each ink head may also be arranged in a staggered manner in the nozzle arrangement direction, or in other words, arranged in two rows in the nozzle arrangement direction. The nozzle arrangement direction may deviate from the first direction D1 within a range of less than 90°. Each nozzle 34 of the color ink head 31 ejects the color ink 36a as ink droplets 37, and each nozzle 34 of the base ink head 32 ejects the base ink 36b as ink droplets 37. Figures 2 to 4 The inkjet head 30 shown is mounted on the carriage 33. When the printer 2 performs side-shift printing, the carriage 33 can move along the second direction D2 as the main scanning direction and the first direction D1 as the sub-scanning direction.

[0099] As a side-shift driving unit 50, it includes a main scanning driving unit 51, a sub-scanning driving unit 52, and a conveying unit 55. Figure 2 The main scanning driving unit 51 shown performs main scanning in which while moving the inkjet head 30 along the second direction D2 as the main scanning direction, ink 36 is ejected from the inkjet head 30 in at least one of the forward direction D11 and the return direction D12. If we focus on the base ink head 32, it can be said that the main scanning driving unit 51 performs main scanning in which the base ink head 32 ejects the base ink 36b while relatively moving along the second direction D2 with respect to the transfer medium M1. Figure 2The sub-scanning drive unit 52 shown performs sub-scanning that moves the inkjet head 30 in the first direction D1, which is the sub-scanning direction, during the main scan. That is, during sub-scanning, the inkjet head 30 moves intermittently in the first direction D1. If we focus on the base ink head 32, it can be said that the sub-scanning drive unit 52 relatively moves the base ink head 32 in the first direction D1 with respect to the transfer medium M1 during the sub-scanning within the main scan. Figure 2 The conveyance unit 55 shown conveys the transfer medium M1, which is a continuous sheet, in the first direction D1, which is the conveyance direction, during the printing of the processing unit area A0. That is, when not printing, the transfer medium M1 moves intermittently in the first direction D1. Figure 2 , 4 The conveyance unit 55 shown conveys the transfer medium M1 in the first direction D1 along the conveyance path 59. The platen 58 is located below the conveyance path 59 and supports the transfer medium M1 by contacting the transfer medium M1 located on the conveyance path 59. The inkjet head 30 controlled by the control unit 10 ejects ink droplets 37 toward the transfer medium M1 supported on the platen 58, thereby attaching the ink 36 to the transfer medium M1.

[0100] The control unit 10 controls the ejection of the colored ink 36a from the colored ink head 31, the ejection of the base ink 36b from the base ink head 32, and the drive unit 50.

[0101] In addition, as long as the base ink 36b can be overlapped on the image IM1 formed by the colored ink 36a, the base ink head 32 can consider various configurations. For example, the base ink head 32 can also be located at a position facing the return direction D11 from the Figure 3 shown C ink head 31C, and can also be located at a position facing the direction opposite to the sub-scanning direction from the colored ink head 31.

[0102] Next, with reference to Figure 5 , 6 and so on, the printing method for the transfer medium M2 will be described. Figure 5 The printing method shown includes the following steps.

[0103] (c1) An image forming step ST1 of performing an image forming process of forming an image IM1 on the transfer medium M1 by ejecting the colored ink 36a from the colored ink head 31.

[0104] (c2) A substrate forming step ST2 of a substrate forming process that includes a process of relatively moving the substrate ink head 32 in a first direction D1 with respect to the transfer medium M1, and a process of overlapping the substrate ink 36b on the image IM1 by ejecting the substrate ink 36b from the substrate ink head 32.

[0105] (c3) An adhesive application step ST3 of applying the adhesive 111 onto the substrate ink 36b that is overlapped on the image IM1 formed on the transfer medium M1.

[0106] (c4) A heating step ST4 of heating the transfer medium M1 to which the adhesive 111 has been applied.

[0107] (c5) A transfer step ST5 of transferring the image IM1 onto the transfer medium M2 by applying the adhesive 111 onto the transfer medium M2.

[0108] In addition, the image forming process is an example of the first process, and the substrate forming process is an example of the second process.

[0109] For example, as Figure 6 shown, a situation is envisioned where the ink 36 is ejected from the inkjet head 30 in units of belts B1 to B6 with respect to the processing unit area A0. For example, in the case where the second main scan for ejecting the substrate ink 36b is performed after the first main scan where the colored ink 36a is ejected for each belt, the image forming step ST1 is performed using the first main scan, and the substrate forming step ST2 is performed using the second main scan. In the case where the first main scan is a main scan in the forward direction D11, the second main scan can be a main scan in the return direction D12 like duplex printing, or a main scan in the forward direction D11 like simplex printing. As long as the substrate ink 36b is overlapped on the image IM1 formed by the colored ink 36a without being mixed, the image forming step ST1 and the substrate forming step ST2 can also be performed using one main scan in the forward direction D11 by the Figure 3 shown inkjet head 30.

[0110] For each belt, the image IM1 can be formed in a single cycle manner, the substrate ink 36b can be overlapped on the image IM1 in a single cycle manner, the image IM1 can be formed in a multi - cycle manner, or the substrate ink 36b can be overlapped on the image IM1 in a multi - cycle manner.

[0111] In Figure 1In the illustrated example, the transfer medium M1 with the base ink 36b overlapped on the image IM1 is intermittently conveyed from the printer 2 to the adhesive supply device 100 and obliquely enters the adhesive tank 110. When the powdery adhesive 111 enters the adhesive tank 110, the adhesive 111 adheres to the base ink 36b that has not yet dried. In Figure 5 it shows the state where the image IM1, the base ink 36b, and the powdery adhesive 111 are sequentially laminated on the transfer medium M1 in the adhesive supply step ST3. The adhesive supply step ST3 is carried out in this way. In Figure 1 In the illustrated example, the transfer medium M1 to which the thermoplastic adhesive 111 has been supplied is intermittently conveyed from the adhesive tank 110 to the heating unit 120. During this period, the excess adhesive 111 is shaken off by tilting the transfer medium M1 again, etc. The heating unit 120 heats the transfer medium M1 to which the adhesive 111 has been supplied. When the transfer medium M1 is heated to a temperature above the melting temperature of the adhesive 111, the adhesive 111 melts. In Figure 5 it shows the state where the image IM1, the dried base ink 36b, and the melted adhesive 111 are sequentially laminated on the transfer medium M1 in the heating step ST4. When the thermal transfer device 200 can heat the transfer medium M1, the heating unit 120 can also perform preheating on the transfer medium M1 to a temperature lower than the melting temperature of the adhesive 111. The heating step ST4 is carried out in this way. In Figure 1 In the illustrated example, the heated transfer medium M1 is intermittently discharged from the heating unit 120. The discharged transfer medium M1 is cut as needed and overlapped on the transfer medium M2 with the surface to which the adhesive 111 has been supplied facing the transfer medium M2, and is sent into the thermal transfer device 200.

[0112] The thermal transfer device 200 presses the transfer medium M1 and the transfer medium M2 in a state where the adhesive 111 given to the transfer medium M1 is in contact with the transfer medium M2. When the thermal transfer device 200 has a heating mechanism, the thermal transfer device 200 heats the transfer medium M1 and the transfer medium M2 to a temperature above the melting temperature of the adhesive 111. In Figure 5In [the figure], a state is shown in which the melted adhesive 111, the dried base ink 36b, the image IM1, and the transfer medium M1 are sequentially laminated on the transfer medium M2. By pressing the transfer medium M1 and the transfer medium M2, the image IM1 adheres to the transfer medium M2 via the base ink 36b and the adhesive 111. In this way, the transfer process ST5 of transferring the image IM1 to the transfer medium M2 is carried out. When the transfer medium M1 is peeled off from the transfer medium M2, the image IM1 remains on the transfer medium M2, and thus the transfer medium M2 with the image IM1 transferred thereon as shown in Figure 1 can be obtained. Since there is a layer of the base ink 36b between the transferred image IM1 and the transfer medium M2, the color of the transfer medium M2 can be prevented from affecting the image IM1, and thus the image quality of the image IM1 is relatively good.

[0113] Although the above-mentioned transfer medium M1 is continuous paper, the transfer medium M1 can also be single-sheet paper. In this case, the user can also put the printed single-sheet paper into the adhesive tank 110 to make the powdery adhesive 111 adhere to the base ink 36b. In this operation, the transfer medium M1 is inclined.

[0114] When the base ink 36b is sprayed onto the image IM1 on the transfer medium M1, it gradually dries. In the processing unit area A0 where the adhesive 111 is supplied at the same timing in the adhesive supply process ST3 with respect to the transfer medium M1, the later the spraying of the base ink 36b becomes, the smaller the drying degree of the base ink 36b. Therefore, when the transfer medium M1 is inclined to supply the adhesive 111 or the like, the base ink 36b with a smaller drying degree sometimes flows downward. If the base ink 36b flows downward, the transferred image IM1 will bleed, resulting in a reduction in the image quality of the transferred image IM1.

[0115] The printing apparatus 1 of this specific example solves the above problem by delaying the base formation process from the middle of the base formation process for the processing unit area A0 until the completion of the base formation process. In addition, the delay of the base formation process is carried out in such a way as to minimize the reduction in the productivity of the adhesive supply process ST3.

[0116] First, with reference to Figure 6 , an example of the area division of the processing unit area A0 and the number of cycles NP of each area will be described. Here, the number of cycles NP refers to the number of main scans accompanied by the ejection of the base ink 36b that are carried out at the same position in the transfer medium M1.

[0117] In the processing unit area A0, the above-mentioned areas b1 to b4 can be cited.Figure 6 An example is shown in which main scanning and sub-scanning are performed in units of belts B1 to B6 with respect to the area b1 of a single sheet of paper or the area b2 during side-shift printing. The control unit 10 controls the main scanning to be performed as follows: while the inkjet head 30 relatively moves with respect to the transfer medium M1 along the second direction D2, ink 36 is ejected for the main scanning. The control unit 10 performs the following control: by relatively moving the colored ink head 31 with respect to the transfer medium M1 in the first direction D1 during the sub-scanning within the main scanning, the position in the first direction D1 where the image IM1 is formed on the transfer medium M1 is changed. In addition, the control unit 10 performs the following control: by relatively moving the base ink head 32 with respect to the transfer medium M1 in the first direction D1 during the sub-scanning, the position in the first direction D1 where the base ink 36b is overlapped on the image IM1 is changed. The image IM1 is formed on the transfer medium M1 in units of belts B1 to B6 in the order of the first direction D1, and the base ink 36b is overlapped on the image IM1 in units of belts B1 to B6 in the order of the first direction D1. Figure 6 The shown processing unit area A0 includes a first area A1 and a second area A2 where the base ink 36b is overlapped on the image IM1 at a later time compared to the first area A1. The second area A2 is an area where the base ink 36b is overlapped on the image IM1 in a main scanning that is later than the main scanning in which the base ink 36b is overlapped on the image IM1 located in the first area A1. In Figure 6 it, various examples C1 to C3 of dividing the belts B1 to B6 are shown.

[0118] In the example C1, the belts B1 and B2 are assigned to the first area A1, the belts B3 and B4 are assigned to the third area A3, and the belts B5 and B6 are assigned to the second area A2. The first area A1 includes the belt B1 where the base ink 36b is first overlapped on the image IM1 in the processing unit area A0. The third area A3 overlaps the base ink 36b on the image IM1 at a later time compared to the first area A1 and at an earlier time compared to the second area A2. The second area A2 includes the belt B6 where the base ink 36b is overlapped on the image IM1 last in the processing unit area A0. The control unit 10 delays the base formation process for the third area A3 and further delays the base formation process for the second area A2. In Figure 6In the substrate formation process shown, the control unit 10 makes the number of cycles NP3 in the third region A3 larger than the number of cycles NP1 in the first region A1, and makes the number of cycles NP2 in the second region A2 larger than the number of cycles NP3 in the third region A3. Therefore, it can be said that the control unit 10 implements control to delay the substrate formation process from the belt B3 in the middle of the substrate formation process for the processing unit region A0 until the substrate formation process is completed. In addition, it can be said that the control unit 10 implements control to further delay the substrate formation process from the belt B5 in the middle of the substrate formation process for the processing unit region A0 until the substrate formation process is completed.

[0119] By delaying the substrate formation process from the middle of the substrate formation process for the processing unit region A0 until the substrate formation process is completed, the drying of the substrate ink 36b at the portion where the substrate ink 36b is finally overlapped on the image IM1 in the processing unit region A0 is promoted. Thereby, the flow of the substrate ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3 can be suppressed. By suppressing the flow of the substrate ink 36b, the bleeding of the transferred image IM1 caused by the downward dripping of the substrate ink 36b or the like can be suppressed, and thus the image quality of the transferred image IM1 is improved.

[0120] When the number of cycles NP increases in the second region A2, the time for the substrate formation process performed on the second region A2 becomes longer. Thereby, the substrate formation process is delayed from the start time point of the substrate formation process for the second region A2 to promote the drying of the substrate ink 36b. When the ejection of the substrate ink 36b is divided into NP main scans, the ejection amount of the substrate ink 36b for each main scan is less for the second region A2 than for the first region A1, which promotes the drying of the substrate ink 36b. Therefore, the flow of the substrate ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3 can be suppressed, and thus the bleeding of the transferred image IM1 can be suppressed by a simple method of changing the number of cycles NP for each region.

[0121] In addition, by making the third region A3 with the number of cycles NP3 that is larger than the number of cycles NP1 and smaller than the number of cycles NP2 located between the first region A1 and the second region A2, the change in the number of cycles NP caused by the region change is reduced. Thereby, the influence on the image quality of the transferred image IM1 caused by the change in the number of cycles NP is small, and thus the image quality of the transferred image IM1 is improved.

[0122] In Example C2, the third area A3 is not present in the processing unit area A0, and belts B1 to B4 are assigned to the first area A1, and belts B5 and B6 are assigned to the second area A2. Even without the third area A3, by increasing the number of cycles NP in the second area A2, the base formation process is delayed from the start time point of the base formation process for the second area A2, so as to promote the drying of the base ink 36b. Therefore, the flow of the base ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3 can be suppressed, and thus bleeding of the transfer image IM1 can be suppressed.

[0123] In Example C3, only the last belt B6 is assigned to the second area A2, and belts B1 to B5 are assigned to the first area A1. Inside the processing unit area A0, the base ink 36b is most likely to flow in the last belt B6. Therefore, in Example C3 as well, the flow of the base ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3 can be effectively suppressed, and thus bleeding of the transfer image IM1 can be effectively suppressed.

[0124] Figure 7 Schematically illustrated is the side-shift intermittent conveyance with respect to the continuous paper M11 as the transfer medium M1.

[0125] The side-shift with respect to the continuous paper M11 is a printing method in which ink 36 is ejected from the inkjet head 30 while the inkjet head 30 scans vertically and horizontally with respect to the processing unit area A0 of the continuous paper M11 in a conveyance stop state, and the continuous paper M11 is conveyed in the conveyance direction by an amount of conveyance L1 corresponding to the processing unit area A0. In Figure 6 In the example shown, the second direction D2 is the main scanning direction, and the first direction D1 is the sub-scanning direction and also the conveyance direction. With respect to the continuous paper M11, the adhesive 111 is supplied at the same timing in the adhesive application step ST3 in units of the amount of conveyance L1. Therefore, the processing unit area A0 becomes an area b2 corresponding to one amount of conveyance L1 in the case of intermittently conveying the continuous paper M11.

[0126] Figure 7The shown state SA1 is a state where the conveyance of the continuous paper M11 as the transfer medium M1 stops and printing is being performed in the processing unit area A01 as the processing unit area A0. When the image IM1 is formed in the processing unit area A01 and the base ink 36b is overlapped on the image IM1, the conveyance unit 55 conveys the continuous paper M11 in the first direction D1 with a predetermined conveyance amount L1. The conveyance amount L1 is a distance obtained by adding a predetermined margin to the length of the processing unit area A0 in the first direction D1. The next state SA2 is a state where the conveyance of the continuous paper M11 stops and printing is being performed in the processing unit area A02 as the processing unit area A0. When the image IM1 is formed in the processing unit area A02 and the base ink 36b is overlapped on the image IM1, the conveyance unit 55 conveys the continuous paper M11 in the first direction D1 with the conveyance amount L1. The next state SA3 is a state where the conveyance of the continuous paper M11 stops and printing is being performed in the processing unit area A03 as the processing unit area A0.

[0127] In the above manner, the printer 2 forms the image IM1 for the processing unit area A0 of the continuous paper M11 in a conveyance stopped state, overlaps the base ink 36b on the image IM1, and intermittently conveys the continuous paper M11 in the first direction D1 with the conveyance amount L1.

[0128] Figure 8 The processing unit area A0 in the single sheet of paper M12 is schematically illustrated. Although the printing for the single sheet of paper M12 can be any one of the side shift type, the serial type, and the line type, Figure 8 An example of performing side shift type or serial type printing on the single sheet of paper M12 is shown.

[0129] In the case where the transfer medium M1 is the single sheet of paper M12, the adhesive 111 is supplied at the same timing in the adhesive application step ST3 for one single sheet of paper M12. Therefore, the processing unit area A0 becomes the area b1 corresponding to the amount of one single sheet of paper.

[0130] In addition, in the printing that performs main scanning and sub-scanning, regarding the difference in the spraying time of the base ink 36b, the sub-scanning direction side is larger than the main scanning direction. Therefore, by delaying the base formation process from the middle of the base formation process to the completion of the base formation process in the sub-scanning direction compared to the main scanning direction, bleeding of the transferred image IM1 can be appropriately suppressed.

[0131] In the case of performing serial printing, the transfer medium M1 is conveyed by an amount corresponding to one sub-scan in the conveyance direction. Even within one main scan, there are differences in the ejection times of the base ink 36b, and thus, the longer the distance of the main scan, the greater the differences in the ejection times of the base ink 36b become. Therefore, it is also considered that a region corresponding to one conveyance amount is set as a processing unit region A0 in the transfer medium M1, and the processing unit region A0 is divided in the main scan direction. In this case, the processing unit region A0 becomes a region b3 corresponding to the conveyance amount of one sub-scan in the case where sub-scanning is performed on the transfer medium M1 on which serial printing is performed.

[0132] In order to reduce waste of the transfer medium M1, in many cases, a plurality of separated images are arranged on the transfer medium M1 in the main scan direction. Therefore, there is a time difference in the ejection of the base ink 36b overlapping on the images in the same main scan. In such a case, by delaying the base formation process from the middle to the completion of the base formation process within one main scan, it is possible to suppress the flow of the base ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3. In such a delay of the base formation process, for example, the case of increasing the processing time of the main scan in the second region A2 is considered.

[0133] In the case of cutting the continuous paper after forming the image IM1 on which the base ink 36b is overlapped by line printing, the adhesive 111 is supplied at the same timing in the adhesive application step ST3 with respect to one transfer medium obtained from the continuous paper. Therefore, the processing unit region A0 becomes a region b4 corresponding to the amount of one cut transfer medium. In the processing unit region A0, the second region A2 is located closer to the printer 2 than the first region A1. In the second region A2, the base ink 36b is overlapped on the image IM1 at a later time than in the first region A1. In such a case, by delaying the base formation process from the middle to the completion of the base formation process for the processing unit region A0, it is possible to suppress the flow of the base ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3. In such a delay of the base formation process, for example, the case of increasing the conveyance time of the transfer medium M1 in the second region A2 is considered.

[0134] (3) Specific examples of the processing of the printing apparatus:

[0135] Figure 9 Schematically illustrated is a printing control process for performing control to form the image IM1 on the transfer medium M1 and overlap the base ink 36b on the image IM1. InFigure 9 Also shown therein is a structural example of a cycle number table T1 for determining the number of cycles NP. The printer 2 can also hold the cycle number table T1 and store the cycle number table T1 in the storage unit 23. Figure 9 The printing control process shown is for side shift type or serial type printing. When a printing instruction for the transfer medium M1 is received from the host device HO1 or the operation panel 24, Figure 4 the control unit 10 shown starts to execute the printing control process.

[0136] When starting the printing control process, the control unit 10 acquires image data DA1 representing the transfer medium M1 from the host device HO1 or the like (step S102). Hereinafter, there are cases where the description of "step" is omitted and the symbol of the step is shown in parentheses.

[0137] After acquiring the image data DA1, the control unit 10 converts the gray value of each pixel into a value representing the usage amounts of the colored ink 36a and the base ink 36b (S104). When the image data DA1 is RGB data and the ink amount data is CMYKW data representing the usage amounts of the inks 36 of C, M, Y, K, and W, the control unit 10 refers to the color conversion LUT and converts each pixel value of R, G, and B into each pixel value of C, M, Y, K, and W. In the color conversion LUT, the gray value of W is set to the value for using the base ink 36b when using at least one of the colored inks 36a of C, M, Y, and K. Thereby, the base ink 36b is overlapped on the position of the image IM1. The gray value of W after color conversion represents the ejection amount of the base ink 36b at the portion overlapped on the image IM1 in the processing unit area A0. Since the ejection amount is represented by 0 to 100%, if the gray value of W is 0 to 255, the gray value of W represents the ejection amount by making the gray values 0 to 255 correspond to the ejection amounts 0 to 100%.

[0138] Next, the control unit 10 performs halftone processing, which is a process of generating dot data that reduces the gray level of the obtained ink amount data to, for example, 2 or 4 (S106). The dot data is generated separately for C, M, Y, K, and W. After the halftone processing, the control unit 10 refers to the cycle number table T1 to determine the cycle number NPi of each area Ai (S108). Here, the area Ai is any one of the first area A1, the second area A2, and the third area A3. The cycle number NPi is any one of the cycle numbers NP1 to NP3.

[0139] The cyclic number table T1 has a cyclic number NP1 associated with the first region A1, a cyclic number NP2 associated with the second region A2, and a cyclic number NP3 associated with the third region A3. In Figure 9 it, a case where NP1 = 4, NP3 = 8, and NP2 = 12 is shown. In this case, the cyclic number NP1 in the first region A1 becomes 4, the cyclic number NP3 in the third region A3 becomes 8, and the cyclic number NP2 in the second region A2 becomes 12. Therefore, the cyclic number NP3 in the third region A3 is greater than the cyclic number NP1 in the first region A1, and the cyclic number NP2 in the second region A2 is greater than the cyclic number NP3 in the third region A3.

[0140] After determining the cyclic number NP, the control unit 10 performs a rasterization process, which is a process of generating raster data obtained by arranging and exchanging dot data in such a way that NPi main scans for overlapping the base ink 36b on the image IM1 are performed after the main scan for forming the image IM1 (S110). For example, it is assumed that the printing unit 20 performs NPi main scans for spraying the base ink 36b after one main scan for spraying the colored ink 36a for each belt in the processing unit region A0. In this case, the control unit 10 generates raster data obtained by arranging and exchanging dot data in such a way that the colored ink 36a is sprayed to form the image IM1 by one main scan, and then the base ink 36b is sprayed to be overlapped on the image IM1 by NPi main scans. Of course, the main scan for spraying the colored ink 36a for each belt may be two or more times, such as NP times.

[0141] Finally, the control unit 10 generates a drive signal SG1 based on the raster data and sends it to the inkjet head 30, thereby controlling the image formation process for forming the image IM1 on the transfer medium M1 and controlling the base formation process for overlapping the base ink 36b on the image IM1 in a manner divided into NPi main scans (S112). The ejection amount of the base ink 36b assigned to each main scan may be equal, or may be unequal, such as making the ejection amount of the NPi-th time less than the ejection amount up to the (NPi - 1)-th time. The drive unit 50 relatively moves the inkjet head 30 with respect to the transfer medium M1 in such a way that the main scan and the sub-scan are performed according to the control implemented by the control unit 10. The colored ink head 31 sprays the colored ink 36a to form the image IM1 on the transfer medium M1 during the main scan, and the base ink head 32 sprays the base ink 36b to overlap the base ink 36b on the image IM1 during the NPi main scans.

[0142] Here, when the number of cycles NP increases in the second region A2 where the base ink 36b is overlapped on the image IM1 later than in the first region A1 and the third region A3, the time for the base formation process performed on the second region A2 becomes longer. As a result, the start time point of the base formation process for the second region A2 is delayed to promote the drying of the base ink 36b. Regarding the ejection amount of the base ink 36b for each main scan, the ejection amount for the second region A2 is smaller than that for the first region A1 and the third region A3, which promotes the drying of the base ink 36b. When the drying of the base ink 36b is promoted, the flow of the base ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3 can be suppressed. Therefore, bleeding of the transferred image IM1 caused by the base ink 36b flowing downward or the like can be suppressed, and the image quality of the transferred image IM1 is improved. In addition, by arranging the third region A3 with the number of cycles NP3 that is more than the number of cycles NP1 and less than the number of cycles NP2 between the first region A1 and the second region A2, the influence on the image quality of the transferred image IM1 caused by the change in the number of cycles NP is small, and the image quality of the transferred image IM1 is improved.

[0143] In addition, the delay of the base formation process from the middle can be, in addition to the increase in the number of cycles NP, an increase in the time of the sub-scan process included in the base formation process for the second region A2.

[0144] In addition, as Figure 10 , 11 illustrated, the control unit 10 can also change the number of cycles NPi of the region Ai according to the area of the continuous region that is connected as one image IM1. Figure 10 A paper for schematically judging the presence or absence of a continuous region exceeding the reference area THS is illustrated. Figure 11 Another structural example of the cycle number table and another example of the printing control process are schematically shown.

[0145] In Figure 10 , a first continuous region A11 having an area S1 that does not exceed the reference area THS and a second continuous region A12 having an area S2 that exceeds the reference area THS are shown. The first continuous region A11 is connected as one image IM1, and the second continuous region A12 is also connected as one image IM1. In Figure 10 , the first region A1 includes a plurality of first continuous regions A11, the second region A2 includes the first continuous region A11 and the second continuous region A12, and the third region A3 includes a plurality of second continuous regions A12.

[0146] The larger the continuous regions (A11, A12) are, the more likely it is for the flow of the base ink 36b caused by the inclination of the transfer medium M1 to occur in the adhesive application step ST3.

[0147] For example, since the first region A1 only includes the first continuous region A11 with a small area, even if the transfer medium M1 inclines in the adhesive application step ST3, the flow of the base ink 36b in the first continuous region A11 included in the first region A1 is less. Although not shown, in the case where there is a second continuous region A12 with a large area in the first region A1, if the transfer medium M1 inclines in the adhesive application step ST3, the flow of the base ink 36b is likely to occur in the second continuous region A12 included in the first region A1. Therefore, the control unit 10 makes the number of cycles NP2 in the case where there is a second continuous region A12 with a large area in the first region A1 more than the number of cycles NP2 in the case where there is no second continuous region A12. Thereby, the drying of the base ink 36b present in the first region A1 is promoted, so that the flow of the base ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3 can be further suppressed, and further, the bleeding of the transfer image IM1 can be further suppressed.

[0148] In Figure 10 Since the second region A2 includes the second continuous region A12 with a large area, if the transfer medium M1 inclines in the adhesive application step ST3, the flow of the base ink 36b is likely to occur in the second continuous region A12 included in the second region A2. In particular, in the second region A2 including the portion where the base ink 36b is finally overlapped on the image IM1 in the processing unit region A0, the flow of the base ink 36b is likely to occur. Although not shown, in the case where the second region A2 only has the first continuous region A11 with a small area, even if the transfer medium M1 inclines in the adhesive application step ST3, the flow of the base ink 36b in the first continuous region A11 included in the second region A2 is less. Therefore, the control unit 10 makes the number of cycles NP2 in the case where there is a second continuous region A12 with a large area in the second region A2 more than the number of cycles NP2 in the case where there is no second continuous region A12. Thereby, the drying of the base ink 36b present in the second region A2 is promoted, so that the flow of the base ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3 can be further suppressed, and further, the bleeding of the transfer image IM1 can be further suppressed.

[0149] In addition, the number of cycles NP2 can be changed according to the area of the continuous region in the second region A2 while the number of cycles NP1 is fixed in the first region A1, or the number of cycles NP1 can be changed according to the area of the continuous region in the first region A1 while the number of cycles NP2 is fixed in the second region A2.

[0150] For the third region A3, the control unit 10 can also make the number of cycles NP3 when there is a second continuous region A12 with a larger area more than the number of cycles NP3 when there is no second continuous region A12.

[0151] Figure 11 The shown cycle number table T2 also has the cycle number NP1 associated with the first region A1, the cycle number NP2 associated with the second region A2, and the cycle number NP3 associated with the third region A3. However, the cycle number NPi changes according to the area of the continuous region. In Figure 11 when there is no second continuous region A12 with an area exceeding the reference area THS in the region Ai, NP1 = 4, NP3 = 8, and NP2 = 12, and when there is a second continuous region A12 in the region Ai, NP1 = 6, NP3 = 10, and NP2 = 14. Therefore, for the region Ai, the number of cycles NPi when including the second continuous region A12 is always more than the number of cycles NPi when not including the second continuous region A12. In addition, the number of cycles NPi within the same region can also be switched in three or more stages.

[0152] Figure 11 The shown printing control process Figure 9 compared with the shown printing control process, replaces the cycle number table T1 with the cycle number table T2 and adds the process of S202 between S106 and S108.

[0153] When the dot data of C, M, Y, K, and W are generated through the processes of S102 to S106, the control unit 10 extracts the continuous regions included in the region Ai and obtains the area of each continuous region (S202). For example, the control unit 10 extracts the continuous regions included in the first region A1, the continuous regions included in the second region A2, and the continuous regions included in the third region A3 based on the image data DA1, RGB data, ink amount data, or dot data, and calculates the area of each continuous region. The area of the continuous region can be obtained, for example, by counting the number of pixels included in the continuous region. Next, the control unit 10 determines the number of cycles NPi of each region Ai with reference to the cycle number table T2 (S108). The control unit 10 determines that the continuous region is the second continuous region A12 when the area of the continuous region exceeds the reference area THS, and determines that the continuous region is the first continuous region A11 when the area of the continuous region does not exceed the reference area THS. Based on this, for each region Ai, the control unit 10 determines the number of cycles NPi of "there is a large-area continuous region" when there is a second continuous region A12, and determines the number of cycles NPi of "there is no large-area continuous region" when there is no second continuous region A12.

[0154] For example, as Figure 10 shown, it is assumed that the first continuous region A11 and the second continuous region A12 are arranged in the processing unit region A0. Since there is no second continuous region A12 in the first region A1, the control unit 10 determines the number of cycles NP1 to be 4. Since there is a second continuous region A12 in the third region A3, the control unit 10 determines the number of cycles NP3 to be 10. Since there is a second continuous region A12 in the second region A2, the control unit 10 determines the number of cycles NP2 to be 14.

[0155] After determining the number of cycles NP, the control unit 10 performs a rasterization process, which is a process of generating raster data after arranging and exchanging dot data in such a way that NPi main scans for overlapping the base ink 36b on the image IM1 are performed after the main scan for forming the image IM1 (S110). Finally, the control unit 10 generates a drive signal SG1 based on the raster data and sends it to the inkjet head 30, thereby controlling the image formation process for forming the image IM1 on the transfer medium M1 and controlling the base formation process for overlapping the base ink 36b on the image IM1 in a manner divided into NPi main scans (S112).

[0156] When there is a second continuous area A12 with a relatively large area in the area Ai, the number of cycles NPi is larger compared to the case where there is no second continuous area A12, so that the flow of the base ink 36b caused by the inclination of the transfer medium M1 in the adhesive application step ST3 can be further suppressed. Therefore, bleeding of the transfer image IM1 can be further suppressed.

[0157] In addition, as Figure 12 illustrated, the control unit 10 can also change the number of cycles NPi of the area Ai according to the ejection amount DT of the base ink 36b per unit area. In addition, the ejection amount DT of the base ink 36b is also referred to as the base ink ejection amount DT. Figure 12 The "ejection amount DT of W" shown refers to the ejection amount DT of the base ink per unit area. Figure 12 An example of changing the number of cycles NPi according to the ejection amount DT of the base ink per unit area is schematically shown. In Figure 12 , a structural example of the cycle number table T3 for determining the number of cycles NPi according to the base ink ejection amount DT is also shown.

[0158] Figure 12 The cycle number table T3 shown also has the number of cycles NP1 associated with the first area A1, the number of cycles NP2 associated with the second area A2, and the number of cycles NP3 associated with the third area A3. However, the number of cycles NPi varies according to the ejection amount DT of the base ink in the area Ai. In Figure 12 , the threshold of the ejection amount DT of the base ink per unit area has a first ejection amount THD1 and a second ejection amount THD2 greater than the first ejection amount THD1. When the ejection amount DT of the base ink in the area Ai does not exceed the first ejection amount THD1, NP1 = 2, NP3 = 3, and NP2 = 4. When the ejection amount DT of the base ink in the area Ai exceeds the first ejection amount THD1 but does not exceed the second ejection amount THD2, NP1 = 4, NP3 = 6, and NP2 = 8. When the ejection amount DT of the base ink in the area Ai exceeds the second ejection amount THD2, NP1 = 8, NP3 = 12, and NP2 = 16. Therefore, it can be said that the cycle number table T3 has information that makes the number of cycles NPi of the area Ai be NP1 < NP3 < NP2 if the ejection amount DT of the base ink remains unchanged.

[0159] For each region Ai, the number of cycles NPi when the ejection amount DT of the base ink per unit area exceeds the first ejection amount THD1 is greater than the number of cycles NPi when the ejection amount DT of the base ink per unit area does not exceed the first ejection amount THD1. For each region Ai, the number of cycles NPi when the ejection amount DT of the base ink per unit area exceeds the second ejection amount THD2 is greater than the number of cycles NPi when the ejection amount DT of the base ink per unit area does not exceed the second ejection amount THD2. Therefore, the "second ejection amount THD2" can also be referred to as the "first ejection amount THD1".

[0160] In addition, the number of cycles NP2 when DT > THD1 can be made greater than the number of cycles NP2 when DT ≤ THD1 in the second region A2, and the number of cycles NP1 can be made fixed regardless of the ejection amount DT of the base ink in the first region A1. Further, the number of cycles NP1 when DT > THD1 can be made greater than the number of cycles NP1 when DT ≤ THD1 in the first region A1, and the number of cycles NP2 can be made fixed regardless of the ejection amount DT of the base ink in the second region A2. The same can be said for the third region A3.

[0161] The printing control process that refers to the cycle number table T3 can be implemented according to Figure 9 the printing control process shown. For example, in S108, the control unit 10 can calculate the average value of the ejection amount of the base ink 36b for the portion overlaid on the image IM1 for each region Ai based on the W data included in the CMYKW data as the ejection amount DT of the base ink. Thereafter, the control unit 10 can refer to the cycle number table T3 and select the cycle number NPi for the section including the ejection amount DT of the base ink for each region Ai.

[0162] As Figure 12 shown, when the ejection amount DT1 of the base ink in the first region A1 exceeds the second ejection amount THD2, the control unit 10 determines the cycle number NP1 as 8 corresponding to "large" of the "first region A1" in the cycle number table T3. When the ejection amount DT3 of the base ink in the third region A3 exceeds the second ejection amount THD2, the control unit 10 determines the cycle number NP3 as 12 corresponding to "large" of the "third region A3" in the cycle number table T3. When the ejection amount DT2 of the base ink in the second region A2 does not exceed the first ejection amount THD1, the control unit 10 determines the cycle number NP2 as 4 corresponding to "small" of the "second region A2" in the cycle number table T3.

[0163] The greater the ejection amount DT of the base ink per unit area, the more likely it is for the base ink 36b to flow due to the inclination of the transfer medium M1 in the adhesive application step ST3. Since the drying of the base ink 36b is promoted by increasing the number of cycles NP in the area where the ejection amount DT of the base ink is large, it is possible to further suppress the flow of the base ink 36b due to the inclination of the transfer medium M1 in the adhesive application step ST3, thereby suppressing bleeding of the transfer image IM1.

[0164] If the ejection amount DT of the base ink remains unchanged, the control unit 10 makes the number of cycles NP3 in the third region A3 larger than the number of cycles NP1 in the first region A1, and makes the number of cycles NP2 in the second region A2 larger than the number of cycles NP3 in the third region A3. Therefore, it can be said that the control unit 10 performs control to delay the base formation process from the middle of the base formation process for the processing unit region A0 until the base formation process is completed. As a result, the drying of the base ink 36b at the portion where the base ink 36b is finally overlapped on the image IM1 in the processing unit region A0 is promoted, thereby suppressing the flow of the base ink 36b due to the inclination of the transfer medium M1 in the adhesive application step ST3. Since Figure 12 the shown cycle number table T3 takes into account both the number of cycles NP related to bleeding of the transfer image IM1 and the ejection amount DT of the base ink, it is possible to appropriately suppress bleeding of the transfer image IM1.

[0165] Although not shown, it is also possible to change Figure 12 the number of cycles NPi in each section of the shown cycle number table T3 according to the area of the continuous region. For example, it can be set that in the second region A2 when DT ≤ THD1, if there is a second continuous region A12 exceeding the reference area THS, then NP2 = 6, and if there is no second continuous region A12, then NP2 = 4. It can be set that in the second region A2 when THD1 < DT ≤ THD2, if there is a second continuous region A12 exceeding the reference area THS, then NP2 = 10, and if there is no second continuous region A12, then NP2 = 8. It can be set that in the first region A1 when DT ≤ THD1, if there is a second continuous region A12 exceeding the reference area THS, then NP1 = 4, and if there is no second continuous region A12, then NP1 = 2. It can be set that in the first region A1 when THD1 < DT ≤ THD2, if there is a second continuous region A12 exceeding the reference area THS, then NP1 = 6, and if there is no second continuous region A12, then NP1 = 4.

[0166] (4) Variant example:

[0167] The present invention contemplates various modifications.

[0168] For example, the subject that implements the above-mentioned processing is not limited to the CPU, and may be an electronic component other than the CPU such as an ASIC (Application Specific Integrated Circuit). Of course, it is also possible to make a plurality of CPUs work together to implement the above-mentioned processing, and it is also possible to make the CPU and other electronic components (such as ASIC) work together to implement the above-mentioned processing.

[0169] Figure 9 , 11 Part of the print control process shown may be executed by the host device HO1. In this case, the control unit of the printing device 1 is a combination of the control unit 10 in a narrow sense and the host device HO1.

[0170] The color combination of the colored ink 36a is not limited to C, M, Y, and K, and may include orange, green, light cyan with a lower concentration than C, light magenta with a lower concentration than M, dark yellow with a higher concentration than Y, and light black with a lower concentration than K. Of course, even when the colored ink 36a does not include inks of some colors among C, M, Y, and K, the embodiment of the present application can also be applied.

[0171] The base ink 36b is not limited to W ink, and may be K ink containing a light absorbing component, gray ink containing a light absorbing component and a light diffusely reflecting component, etc. In addition, a transparent ink that transmits light while transmitting the color of the transfer medium M2 that serves as the background of the image IM1 may also be used as the base ink 36b.

[0172] (5) Summary:

[0173] As described above, according to the present invention, a structure capable of suppressing the bleeding of a transferred image can be provided in various forms. Of course, even a technique consisting only of the constituent elements according to the independent claims can achieve the above-mentioned basic functions and effects.

[0174] In addition, it is also possible to implement a structure obtained by replacing each structure disclosed in the above examples with each other or changing the combination, a structure obtained by replacing each structure disclosed in the above examples with each other or changing the combination, etc. The present invention also includes these structures, etc.

[0175] Explanation of symbols

[0176] 1... Printing device; 2... Printer; 10... Control unit; 20... Printing unit; 30... Inkjet head; 30a... Nozzle surface; 31... Colored ink head; 32... Base ink head; 33... Carriage; 34... Nozzle; 36... Ink; 36a... Colored ink; 36b... Base ink; 37... Ink droplet; 50... Driving unit; 51... Main scanning driving unit; 52... Sub-scanning driving unit; 55... Conveying unit; 100... Adhesive supply device; 110... Adhesive tank; 111... Adhesive; 120... Heating unit; 200... Thermal transfer device; A0, A01, A02, A03... Processing unit area; A1... First area; A2... Second area; A3... Third area; A11... First continuous area; A12... Second continuous area; D1... First direction; D2... Second direction; D11... Outward journey direction; D12... Return journey direction; DA1... Image data; DT... Jetting amount; IM1... Image; L1... Conveying amount; M1... Transfer medium; M2... Medium to be transferred; M11... Continuous paper; M12... Sheet paper; NP... Number of cycles; ST1... Image forming process; ST2... Base forming process; ST3... Adhesive supply process; ST4... Heating process; ST5... Transfer process; T1 to T3... Cycle number table; THD1... First jetting amount; THD2... Second jetting amount; THS... Reference area.

Claims

1. A printing method, which performs printing on a transfer medium by performing an adhesive application step and a transfer step, wherein the adhesive application step is a step of attaching an adhesive to a base ink, the base ink being superimposed on an image formed on the transfer medium, and the transfer step is a step of attaching the adhesive to a transfer medium to transfer the image to the transfer medium, wherein: The printing method comprises: An image forming step of performing a first process of forming the image on the transfer medium by ejecting a color ink from a first inkjet head; The base forming step includes performing a second process including a process of superimposing the base ink on the image by ejecting the base ink from the second inkjet head onto the transfer medium. A region to which the adhesive is supplied at the same timing with respect to the transfer medium in the adhesive supplying step is defined as a processing unit region, In the base forming step, the second process is delayed from the middle of the second process on the process unit area to the completion of the second process.

2. The printing method according to claim 1, wherein: The processing unit area includes a first area and a second area in which the base ink is overlapped on the image at a later time than the first area. The second area includes a portion in the processing unit area where the base ink is finally overlapped on the image. In the base forming step, the second treatment on the second region is delayed.

3. The printing method according to claim 2, wherein: In the base forming step, the second processing is performed as follows: a main scan is performed to eject the base ink while the second inkjet head is moved relative to the transfer medium along a second direction, and the position in the first direction where the base ink is overlapped on the image is changed by moving the second inkjet head relative to the transfer medium in a first direction intersecting the second direction in a sub-scan during the main scan. The number of main scans performed at the same position on the transfer medium accompanied by the ejection of the base ink is defined as the number of cycles. In the base forming step, the second treatment is performed such that the number of cycles in the second region is greater than the number of cycles in the first region.

4. The printing method according to claim 3, wherein: The processing unit area includes a continuous area connected into one as the image, In the base forming step, in at least one of the first region and the second region, the number of cycles when the continuous region exceeding the reference area exists is greater than the number of cycles when the continuous region exceeding the reference area does not exist.

5. The printing method according to claim 2, wherein: In the base forming step, the second processing is performed as follows: a main scan is performed to eject the base ink while the second inkjet head is moved relative to the transfer medium along a second direction intersecting the first direction, and the position in the first direction of overlapping the base ink on the image is changed by moving the second inkjet head relative to the transfer medium in the first direction during a sub-scan during the main scan. The number of main scans performed at the same position on the transfer medium accompanied by the ejection of the base ink is defined as the number of cycles. In the base forming step, the second treatment is implemented as follows, namely: in at least one of the first area and the second area, the number of cycles when the ejection amount of the base ink per unit area exceeds the first ejection amount is greater than the number of cycles when the ejection amount of the base ink per unit area does not exceed the first ejection amount, and the number of cycles in the second area is greater than the number of cycles in the first area when the ejection amount of the base ink per unit area remains unchanged.

6. The printing method according to claim 1 or claim 2, wherein: The base ink is an ink containing a component that blocks the transmission of light.

7. A printing device for printing on a transfer medium by performing an adhesive application step and a transfer step, wherein the adhesive application step is a step of attaching an adhesive to a base ink, the base ink being superimposed on an image formed on the transfer medium, and the transfer step is a step of attaching the adhesive to a transfer medium to transfer the image to the transfer medium, wherein: The printing device comprises: a first inkjet head that ejects colored ink; a second inkjet head for ejecting the base ink; a driving unit configured to move the second inkjet head relative to the transfer medium in a first direction; a control unit that controls the ejection of the color ink from the first inkjet head, the ejection of the base ink from the second inkjet head, and the drive unit, The control unit implements the following control, namely: controlling a first process of forming the image on the transfer medium by ejecting the colored ink from the first inkjet head, controlling a second process including a process of superimposing the base ink on the image by ejecting the base ink from the second inkjet head onto the transfer medium, A region to which the adhesive is supplied at the same timing with respect to the transfer medium in the adhesive supplying step is defined as a processing unit region, The control unit performs control to delay the second processing from midway through the second processing on the processing unit area until the second processing is completed.

Images