Image forming apparatus, image forming method, and image forming program

Abstract

This invention provides an image forming apparatus, an image forming method, and an image forming program that contribute to suppressing the degradation of image quality transferred to a print medium. [Solution] The image forming apparatus forms an ink layer L1 on a film F which is to be transferred to a printing medium M. The image forming apparatus comprises a color head for ejecting color ink, a shielding head for ejecting shielding ink, and a control unit. The control unit ejects color ink from the color head onto the film F, thereby forming a color layer L11 on the film F which is composed of color ink, constitutes an image, and is the ink layer L1. On the film F on which the color layer L11 has been formed, the control unit ejects shielding ink from the shielding head onto the color layer L11, thereby forming shielding layers L13 and L15 which are composed of shielding ink and are the ink layer L1.

Description

Technical Field

[0001] The present invention relates to an image forming apparatus, an image forming method, and an image forming program.

Background Art

[0002] In the image forming method described in Patent Document 1, an image is formed on an intermediate transfer recording medium by an inkjet method. The intermediate transfer recording medium on which the image is formed is overlaid on a printing medium. The printing medium is heated in a state where it is overlaid on the intermediate transfer recording medium. Thereby, the image is transferred from the intermediate transfer recording medium to the printing medium.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above image forming method, when the image is transferred from the intermediate recording medium to the printing medium, the printing medium is heated. In this case, there is a possibility that so-called sublimation migration occurs, in which the dye contained in the printing medium moves from the printing medium to the transferred image due to heat. When the dye moves to the transferred image, the dye becomes conspicuous with respect to the transferred image, and the quality of the transferred image may deteriorate.

[0005] <舍 An object of the present invention is to provide an image forming apparatus, an image forming method, and an image forming program that contribute to suppressing a decrease in the quality of an image transferred to a printing medium.

Means for Solving the Problems

[0006] An image forming apparatus according to a first aspect of the present invention is an image forming apparatus for forming an ink layer on a film to be transferred to a printing medium, comprising a color head for ejecting color ink, a shielding head for ejecting shielding ink, and a control unit, wherein the control unit ejects the color ink from the color head onto the film to form a color layer on the film that is composed of the color ink and constitutes an image, and is an ink layer, and in the film on which the color layer has been formed, the shielding head ejects the shielding ink onto the color layer to form a shielding layer that is composed of the shielding ink and is an ink layer.

[0007] According to the first embodiment, a shielding layer exists on top of the color layer in the film. In this state, for example, when an ink layer is transferred from the film to a printing medium, the distance from the printing medium to the color layer becomes at least as long as the shielding layer. Therefore, if the printing medium contains dye, the shielding layer prevents the dye contained in the printing medium from reaching the color layer from the printing medium by sublimation transfer. As a result, the shielding layer prevents the dye from being visible against the color layer. Thus, the image forming apparatus contributes to suppressing a decrease in the quality of the image transferred to the printing medium.

[0008] In the image forming apparatus, the shielding head may dispense black ink as the shielding ink.

[0009] In this case, a shielding layer is formed by black ink. Therefore, the shielding layer further suppresses the visibility of the dye against the color layer. Thus, the image forming apparatus further contributes to suppressing the degradation of image quality transferred to the print medium.

[0010] The image forming apparatus includes a white head for ejecting white ink, and the control unit may, in the film on which the color layer is formed, eject the white ink from the white head onto the color layer to form a white layer composed of the white ink and which is the ink layer, and in the film on which the white layer is formed, eject the shielding ink from the shielding head onto the white layer to form the shielding layer.

[0011] In this case, a white layer exists between the shielding layer and the color layer. Therefore, when the ink layer is transferred from the film to the printing medium, the white layer prevents the color development of the color layer from being degraded by the shielding layer. Thus, the image forming apparatus further contributes to suppressing the deterioration of the image quality transferred to the printing medium.

[0012] In the image forming apparatus, the control unit controls the white head and the shielding head, and in the film on which the color layer is formed, the white layer and the shielding layer may be treated as a single unit set, and a plurality of such unit sets may be formed on the color layer.

[0013] In this case, multiple unit sets exist on the color layer of the film. In this state, if, for example, the ink layer is transferred from the film to the printing medium, the distance from the printing medium to the color layer will be increased by at least the length of the multiple unit sets. Therefore, if the printing medium contains dye, the multiple unit sets suppress the dye contained in the printing medium from reaching the color layer through sublimation transfer. As a result, the multiple unit sets suppress the visibility of the dye against the color layer. Thus, the image forming apparatus further contributes to suppressing the deterioration of the image quality transferred to the printing medium.

[0014] In the image forming apparatus, the control unit may discharge an amount of shielding ink from the shielding head corresponding to the amount of white ink discharged by the white head.

[0015] In this case, the image forming apparatus contributes, for example, to changing the thickness of the shielding layer according to the thickness of the white layer.

[0016] In the image forming apparatus, the control unit may dispense an amount of the shielding ink corresponding to the type of film from the shielding head.

[0017] In this case, the image forming apparatus contributes to forming a shielding layer of a thickness suitable for the type of film.

[0018] In the image forming apparatus, the control unit may discharge an amount of the shielding ink from the shielding head in a quantity corresponding to the temperature, pressure, or time set in the transfer step performed when transferring the image from the film to the printing medium.

[0019] In this case, the image forming apparatus contributes to forming a shielding layer of appropriate thickness for the temperature, pressure, or time during the transfer process.

[0020] In the image forming apparatus, the control unit may discharge an amount of the shielding ink from the shielding head corresponding to the type of printing medium on which the image is transferred from the film.

[0021] In this case, the image forming apparatus contributes to forming a shielding layer of a thickness suitable for the type of printing medium.

[0022] In the image forming apparatus, the control unit may dispense an amount of the shielding ink from the shielding head in proportion to a setting value specified by the user.

[0023] In this case, the image forming apparatus contributes, for example, to forming a shielding layer according to the image quality required by the user.

[0024] In the image forming apparatus, the control unit may eject the shielding ink onto an area that coincides with the color area where the color layer is formed, an area that coincides with the white area where the white layer is formed, or an area inside either the color area or the white area from the shielding head.

[0025] In this case, it is possible to suppress the shielding layer from protruding from the color layer or the white layer. Therefore, the image forming apparatus further contributes to suppressing a decrease in the quality of the image transferred onto the print medium.

[0026] In the image forming apparatus, in the film on which the color layer is formed, the control unit may form the shielding layer having a complementary color to the color of the print medium onto which the image is transferred from the film by ejecting the shielding ink onto the color layer from the shielding head.

[0027] In this case, the shielding layer has a complementary color. Therefore, the shielding layer further suppresses the dye from being conspicuous with respect to the color layer. Therefore, the image forming apparatus further contributes to suppressing a decrease in the quality of the image transferred onto the print medium.

[0028] In the image forming apparatus, the control unit may perform in parallel a color scan in which the color ink is ejected and scanned from the color head, a white scan in which the white ink is ejected and scanned from the white head, a shielding scan in which the shielding ink is ejected and scanned from the shielding head, and the white scan, or the color scan, the shielding scan, and the white scan may be performed in parallel.

[0029] In this case, the color scan, the shielding scan, and the white scan are executed in a shorter time than when the white scan is performed separately from both the color scan and the shielding scan. Therefore, the image forming apparatus contributes to suppressing a decrease in the quality of the image transferred onto the print medium while suppressing a deterioration in productivity.

[0030] The image forming apparatus includes a heat platen on which the film is placed and which is equipped with a heater, and the control unit may form the color layer on the film by ejecting the color ink from the color head onto the film placed on the heat platen heated by the heater, and may form the shielding layer on the film, which is placed on the heat platen heated by the heater and on which the color layer has been formed, by ejecting the shielding ink from the shielding head onto the color layer.

[0031] In this case, the image forming apparatus further contributes to suppressing the degradation of image quality transferred to the print medium.

[0032] A second aspect of the present invention is an image forming method for forming an ink layer on a film to be transferred to a printing medium, characterized in that a color layer, which is composed of the color ink and constitutes an image, is formed on the film by ejecting the color ink from a color head that ejects color ink onto the film, and a shielding layer, which is composed of the shielding ink and constitutes the ink layer, is formed on the film on which the color layer has been formed by ejecting the shielding ink from a shielding head that ejects shielding ink onto the color layer.

[0033] The second embodiment, like the first embodiment, contributes to suppressing the degradation of image quality transferred to a print medium.

[0034] An image forming program according to a third aspect of the present invention is an image forming program for forming an ink layer on a film to be transferred to a printing medium, characterized in that the computer ejects color ink from a color head that ejects color ink onto the film, thereby forming a color layer on the film that is composed of the color ink and constitutes an image, and that is the ink layer, and in the film on which the color layer has been formed, ejects shielding ink from a shielding head that ejects shielding ink onto the color layer, thereby forming a shielding layer that is composed of the shielding ink and that is the ink layer.

[0035] The third embodiment, like the first embodiment, contributes to suppressing the degradation of image quality transferred to a print medium. [Brief explanation of the drawing]

[0036] [Figure 1] This is a diagram of the printing system 100. [Figure 2] This is a flowchart for DTF printing. [Figure 3] This is a cross-sectional view showing the process from film F to the creation of the printed result G in DTF printing. [Figure 4] This is a schematic plan view of printer 21. [Figure 5] This is a schematic right side view of printer 21. [Figure 6] This is a block diagram showing the electrical configuration of printer 21. [Figure 7] This is a flowchart of the main process. [Figure 8] This is a plan view of film F. [Figure 9] This is a cross-sectional view of the printed product G. [Modes for carrying out the invention]

[0037] A printing system 100 according to one embodiment of the present invention will be described with reference to the drawings. As shown in Figure 1, the printing system 100 includes a printer 21, an oven 22, and a heat press machine 23.

[0038] As will be explained in more detail later, printer 21 is an inkjet printer. Printer 21 ejects white ink, color ink, and opacity ink.

[0039] White ink is white ink. White ink contains, for example, a pigment. A pigment is, for example, titanium dioxide.

[0040] Color ink is an ink of a color other than white. The color of the color ink is not limited to a specific color. In this embodiment, the color ink is cyan, magenta, yellow, and black ink.

[0041] The opacifying ink is an ink of a color other than white. In this embodiment, the opacifying ink is black ink. That is, the opacifying ink is black ink. The black color of the opacifying ink may be the same as the black color of the color ink. The black color of the opacifying ink may be different from the black color of the color ink.

[0042] The shielding ink is an ink used to suppress sublimation transfer. For example, the percentage of the component that suppresses sublimation transfer contained in the shielding ink is higher than the percentage of the component that suppresses sublimation transfer contained in the white ink. Alternatively, the percentage of the component that promotes sublimation transfer contained in the shielding ink is lower than the percentage of the component that promotes sublimation transfer contained in the white ink. The component that suppresses sublimation transfer is, for example, melamine which forms a cross-linked resin film in the baking process (S3) or the transfer process (S4).

[0043] In the following, when white ink, colored ink, and opaque ink are not specified, or when referring to them collectively, the term "ink" is used. Ink may contain pigments or dyes.

[0044] In this embodiment, the ink comprises a pigment and an organic solvent. The pigment is a colorant. The organic solvent may function, for example, as a wetting agent to suppress the drying of the aqueous ink at the nozzle tip of the head 10, as described later. The ink may also contain other components.

[0045] In the printing system 100, DTF printing as shown in Figure 2 is performed by the printer 21, oven 22, and heat press machine 23. DTF printing is Direct To Film printing. DTF printing is a type of printing method for forming a color image on a printing medium M as shown in Figure 3. The printing medium M can be fabric, paper, etc. For example, the printing medium M is a T-shirt.

[0046] DTF printing will be explained with reference to Figures 2 and 3. As shown in Figure 2, DTF printing includes an image formation step (S1), a powder coating step (S2), a baking step (S3), and a transfer step (S4). The image formation step (S1), powder coating step (S2), baking step (S3), and transfer step (S4) are performed in the order of image formation step (S1), powder coating step (S2), baking step (S3), and transfer step (S4). As shown in Figure 3, in DTF printing, the state transitions in the order of state ST1, ST2, ST3, ST4, and ST5.

[0047] As shown in state ST1 in Figure 3, a film F is used in DTF printing. The film F is a thin film. The film F includes a substrate F1 and a receiving layer F2.

[0048] The base material F1 is thin paper or plastic film. The base material F1 may also be a composite film of thin paper and plastic film.

[0049] The receiving layer F2 is laminated on the substrate F1. The receiving layer F2 contains components for agglomerating the ink. The components for agglomerating the ink are, for example, polyvalent metal salts. The receiving layer F2 may further contain, for example, a cationic urethane resin, a cationic fixative, and a filler.

[0050] The receiving layer F2 is transparent to visible light. Furthermore, the receiving layer F2 causes the ink applied to it to aggregate. As a result, the ink layer L1, described later, becomes fixed to the receiving layer F2.

[0051] Although not shown in the diagram, the film F may have a release layer between the substrate F1 and the receiving layer F2. Note that Figure 3 does not show the actual thickness relationship of each layer. For example, the thickness of the substrate F1 may be greater than the thickness of the receiving layer F2. The thickness of the substrate F1 may be less than the thickness of the receiving layer F2.

[0052] As shown in state ST2 of Figure 3, in the image forming process (S1) shown in Figure 2, the printer 21 shown in Figure 1 ejects ink onto the receiving layer F2 of the film F. In this embodiment, the printer 21 ejects white ink, color ink, and occluding ink. As a result, the printer 21 shown in Figure 1 forms an ink layer L1 on the receiving layer F2 of the film F. Note that in state ST2, the ink layer L1 is shown on the receiving layer F2. The receiving layer F2 and the ink layer L1 may become integrated by fixing the ink layer L1 to the receiving layer F2.

[0053] The ink layer L1 is composed of ink. In this embodiment, the ink layer L1 includes a color layer L11, a white layer L12, a shielding layer L13, a white layer L14, and a shielding layer L15. The color layer L11, white layer L12, shielding layer L13, white layer L14, and shielding layer L15 are arranged in the order of color layer L11, white layer L12, shielding layer L13, white layer L14, and shielding layer L15 from the receiving layer F2 upwards. In state ST2, the upward direction is the direction in which the receiving layer F2 is laminated relative to the substrate F1.

[0054] In the following, the white layer and the shielding layer stacked on top of the white layer are considered as a single unit set. In state ST2 of Figure 3, the white layer L12 and the shielding layer L13 constitute one unit set. The white layer L14 and the shielding layer L15 also constitute one unit set. In other words, in state ST2 of Figure 3, two unit sets are formed on top of the color layer L11.

[0055] The color layer L11 is composed of color inks. The color layer L11 constitutes a color image. The color layer L11 may also contain white ink that constitutes the white areas in the color image.

[0056] White layers L12 and L14 are each composed of white ink. White layers L12 and L14 form the background for the color image.

[0057] The shielding layers L13 and L15 are each composed of shielding ink. The shielding layers L13 and L15 each have the function of suppressing the degradation of the quality of the color image transferred to the printing medium M.

[0058] As shown in state ST3 in Figure 3, in the powder coating process (S2) shown in Figure 2, a worker or coating device applies powder onto the ink layer L1 on the film F in which the ink layer L1 is formed. As a result, a powder layer LP is formed on top of the ink layer L1. The powder layer LP is composed of powder.

[0059] The powder is composed of, for example, thermoplastic polyurethane. The powder layer LP is interposed between the ink layer L1 and the printing medium M in the transfer process (S4) described later, improving the adhesion of the ink layer L1 to the printing medium M. The powder layer LP functions as an adhesive layer.

[0060] In the baking process (S3) shown in Figure 2, the film F, on which the powder layer LP has been formed in the ink layer L1, is baked in the oven 22 shown in Figure 1. This causes the powder layer LP to melt.

[0061] As shown in state ST4 in Figure 3, the film F, in which the ink layer L1 and powder layer LP are laminated, is inverted from the state shown in state ST3 and placed on the printing medium M in this inverted state. In the transfer process (S4) shown in Figure 2, the film F and the printing medium M are heat-pressed from above and below by the heat press machine 23 shown in Figure 1, with the ink layer L1 in between. As a result, the ink layer L1 is transferred from the film F to the printing medium M. The image is then transferred from the film F to the printing medium M.

[0062] The heating temperature of the heat press machine 23 is, for example, around 180°C. The heating temperature of the heat press machine 23 is not limited to a specific temperature, but 110°C or higher is preferred.

[0063] As shown in state ST5 in Figure 3, the user peels the substrate F1 from the printing medium M. This allows the user to obtain a printed medium M with a color layer L11 formed on it as the printed result G. In other words, the user obtains a printed medium M with a color image formed on it as the printed result G.

[0064] The schematic configuration of printer 21 will be explained with reference to Figures 4 and 5. In Figure 4, the left, right, bottom, and top correspond to the left, right, front, and rear of printer 21, respectively. In Figure 5, the left, right, bottom, and top correspond to the front, rear, bottom, and top of printer 21, respectively.

[0065] The printer 21 includes a platen transport mechanism 11, a platen 7, a head transport mechanism 12, and a plurality of heads 10.

[0066] The platen transport mechanism 11 comprises guide rails 111 and 112 and a support base 8. The guide rails 111 and 112 each extend in the front-rear direction. The guide rails 111 and 112 are aligned with each other in the left-right direction. The guide rails 111 and 112 are fixed to the frame of a printer 21 (not shown).

[0067] The support base 8 is supported by a pair of guide rails 111 and 112. The support base 8 moves in the forward and backward direction along the pair of guide rails 111 and 112.

[0068] A platen 7 is mounted on the upper end of the support base 8. As indicated by arrow Y2, the platen transport mechanism 11 transports the platen 7 in the front-rear direction by the drive of the sub-scanning motor 14 shown in Figure 6. Therefore, the front-rear direction of the printer 21 is the sub-scanning direction.

[0069] The platen 7 has a plate-like shape. The platen 7 extends in the front-to-back and left-to-right directions. A mounting surface 71 is formed on the upper surface of the platen 7. The film F is placed on the mounting surface 71 with the base material F1 facing downwards and the receiving layer F2 facing upwards. In this way, the film F is set on the platen 7.

[0070] In this embodiment, the platen 7 is a heat platen. That is, the platen 7 includes a heater 70. The heater 70 includes a heat-generating resistor. In this embodiment, the heater 70 is a heating wire. The heater 70 is stretched across the lower surface of the platen 7.

[0071] The heater 70 may be arranged on the mounting surface 71. The heater 70 may also be arranged inside the platen 7.

[0072] The heater 70 generates heat when power is applied, heating the platen 7. When the film F is set on the platen 7, the heater 70 heats the film F through the platen 7.

[0073] The head transport mechanism 12 comprises guide rails 121 and 122 and a carriage 2. The guide rails 121 and 122 each extend in the left-right direction. The guide rails 121 and 122 are aligned with each other in the front-back direction. The guide rails 121 and 122 are fixed to the frame of a printer 21 (not shown).

[0074] The carriage 2 has a plate-like shape. The carriage 2 extends in the front-to-back and left-to-right directions. The carriage 2 is supported by guide rails 121 and 122. The carriage 2 moves in the left-to-right direction along the guide rails 121 and 122.

[0075] The carriage 2 is equipped with multiple heads 10. As indicated by arrow Y1, the head transport mechanism 12 transports the multiple heads 10 in the left-right direction by the drive of the main scanning motor 13 shown in Figure 6. Therefore, the left-right direction of the printer 21 is the main scanning direction.

[0076] The multiple heads 10 have a rectangular parallelepiped shape. In this embodiment, the multiple heads 10 include a white head 3, a color head 4, and a shielding head 5. The white head 3, the color head 4, and the shielding head 5 are arranged in a line from front to back in the order of color head 4, white head 3, and shielding head 5.

[0077] The lower surfaces of the white head 3, the color head 4, and the shielding head 5 are located above the mounting surface 71 of the platen 7. The lower surfaces of the white head 3, the color head 4, and the shielding head 5 are exposed downwards through openings provided in the carriage 2 (not shown).

[0078] Multiple nozzles 31 are formed on the underside of the white head 3. The multiple nozzles 31 are openings. White ink is supplied to the white head 3 from a white ink container (not shown). The white head 3 discharges the white ink downwards from the multiple nozzles 31. In this embodiment, the "container" is a cartridge or a tank.

[0079] Multiple nozzles 41 are formed on the underside of the color head 4. The multiple nozzles 41 are open. Color ink is supplied to the color head 4 from multiple color ink containers (not shown). The color head 4 ejects the color ink downwards from the multiple nozzles 41.

[0080] Multiple nozzles 51 are formed on the lower surface of the shielding head 5. The multiple nozzles 51 are open. Shielding ink is supplied to the shielding head 5 from a shielding ink container (not shown). The shielding head 5 ejects the shielding ink downward from the multiple nozzles 51.

[0081] If the opacity ink and the color ink are the same ink, the black ink container and the opacity ink container in the color ink container may be a single common container or separate containers. If they are a common container, the common container supplies black ink to both the color head 4 and the opacity head 5. If they are separate containers, the black ink container supplies black ink to the color head 4, and the opacity ink container supplies black ink to the opacity head 5.

[0082] If the black color of the opacity ink and the black color of the color ink are different, the black ink container for the color ink and the opacity ink container are separate containers. In this case, the black ink container supplies black ink as color ink to the color head 4, and the opacity ink container supplies black ink as black ink to the opacity head 5.

[0083] As shown in Figure 5, the platen 7 is transported in the front-rear direction between the front end position P11 and the rear end position P12 by the platen transport mechanism 11. At the front end position P11, the platen 7 is positioned in front of the front ends of the multiple heads 10. At the rear end position P12, the platen 7 is positioned behind the rear ends of the multiple heads 10. For example, with the platen 7 positioned at the front end position P11, the film F is set on the platen 7.

[0084] As shown in Figure 4, the head 10 is transported horizontally by the head transport mechanism 12 between the left end position P21 and the right end position P22. At the left end position P21, the head 10 is positioned to the left of the left end of the platen 7. At the right end position P22, the head 10 is positioned to the right of the right end of the platen 7.

[0085] As indicated by arrows Y1 and Y2, in a plan view, the movement paths of the multiple heads 10 and the movement path of the platen 7 intersect with each other. The region where the movement paths of the multiple heads 10 and the movement path of the platen 7 intersect with each other in a plan view is called the "intersection region". When the multiple heads 10 and the platen 7 are positioned in the intersection region, they are in a facing position.

[0086] In the opposing configuration, at least one of the lower surfaces of the multiple heads 10 and the mounting surface 71 of the platen 7 face each other in the vertical direction with the film F in between. In this embodiment, at least one of the lower surfaces of the multiple heads 10 is at least one of the lower surfaces of the white head 3, the color head 4, or the shielding head 5.

[0087] In the facing state, the operation of transporting the head 10 in the left-right direction while ejecting ink from the head 10 is called "head 10 ejection scanning." For example, in the facing state, the ejection scanning of transporting the white head 3 in the left-right direction while ejecting white ink from the nozzle 31 to the white head 3 is called "white head 3 ejection scanning." The operation of transporting the platen 7 in the front-back direction is called "platen 7 sub-scanning." The printer 21 forms an ink layer L1 on the film F by repeatedly performing head 10 ejection scanning and a predetermined amount of sub-scanning of the platen 7.

[0088] Referring to Figure 6, the electrical configuration of the printer 21 will be described. The printer 21 comprises a CPU 91, flash memory 92, and RAM 93. The CPU 91, flash memory 92, and RAM 93 are electrically connected to each other. The CPU 91 controls the printer 21.

[0089] The flash memory 92 is a non-volatile memory. The flash memory 92 stores various types of information. For example, the flash memory 92 stores print data and programs. The print data includes various types of information that the printer 21 uses to form the ink layer L1 shown in Figure 3 on the film F.

[0090] The program consists of computer-readable instructions. The program is executed by the CPU 91. When the program is executed by the CPU 91, it instructs the CPU 91 to perform various processes. The program includes a control program for executing the main process, which is shown in Figure 7 and described later.

[0091] RAM93 temporarily stores data. This data includes flags used in the main process, and information obtained, identified, calculated, or determined during the main process.

[0092] The CPU 91 is electrically connected to the main scanning motor 13, the sub-scanning motor 14, the white head drive unit 30, the color head drive unit 40, the shielding head drive unit 50, and the heater 70. The main scanning motor 13, under the control of the CPU 91, transports multiple heads 10 together with the carriage 2 in the left-right direction. The sub-scanning motor 14, under the control of the CPU 91, transports the platen 7 together with the support base 8 in the front-back direction.

[0093] The white head drive unit 30 is, for example, a heating element or a piezoelectric element. The white head drive unit 30 is positioned corresponding to each of the multiple nozzles 31. The white head drive unit 30 selectively ejects white ink from the multiple nozzles 31 to the white head 3 under the control of the CPU 91.

[0094] The color head drive unit 40 is, for example, a heating element or a piezoelectric element. The color head drive unit 40 is positioned corresponding to each of the multiple nozzles 41. The color head drive unit 40 selectively ejects color ink from the multiple nozzles 41 to the color head 4 under the control of the CPU 91.

[0095] The shielding head drive unit 50 is, for example, a heating element or a piezoelectric element. The shielding head drive unit 50 is positioned corresponding to each of the multiple nozzles 51. The shielding head drive unit 50 selectively ejects shielding ink from the multiple nozzles 51 to the shielding head 5 under the control of the CPU 91.

[0096] Heater 70 generates heat through control by CPU 91.

[0097] The CPU 91 is further electrically connected to a display 97 and an operation unit 98. The display 97 displays various screens under the control of the CPU 91.

[0098] The control unit 98 is a user interface. The control unit 98 is, for example, a button or a touch panel. The control unit 98 outputs signals to the CPU 91 in response to user operations. For example, the control unit 98 accepts a print start operation.

[0099] The print initiation operation is performed by the user. The print initiation operation is the operation to input a print command to the printer 21, which will then print based on the print data. The print command specifies the print data to be controlled.

[0100] Referring to Figure 7, the main process will be explained. The main process is performed in the image forming process (S1) shown in Figure 2. When the printer 21 is powered on, the CPU 91 reads the control program from the flash memory 92 and starts the main process.

[0101] In this embodiment, the main process is assumed to start with the platen 7 positioned at the front end position P11 as shown in Figures 4 and 5. The main process is assumed to start with the head 10 positioned at the left end position P21 or the right end position P22 as shown in Figure 4. Below, an example of forming the ink layer L1 shown in state ST2 of Figure 3 on the film F will be described.

[0102] When the main processing starts, the CPU 91 heats up the heater 70 shown in Figure 5 (S10). This heats the platen 7. The heating temperature of the heater 70 is not limited to a specific temperature, but it is preferably between 30°C and 60°C.

[0103] The CPU 91 determines whether it has received a print command via the control unit 98 shown in Figure 6 (S11). For example, with the film F set on the platen 7 shown in Figure 4, the user performs a print start operation on the control unit 98 and inputs a print command to the printer 21.

[0104] If no print command is received (S11: NO), CPU 91 returns to the decision in S11. If a print command is received (S11: YES), CPU 91 retrieves the target data from the print data specified by the print command (S12).

[0105] In this embodiment, the print data includes the target data. The target data indicates the amount of white ink. The amount of white ink is the total amount of white ink ejected from the white head 3 shown in Figures 4 and 5 by a predetermined number of forming processes (S21) described later. For example, if the color image to be printed includes white areas, the amount of white ink does not need to include the amount of white ink that constitutes the white areas in the color image. In this embodiment, regardless of whether or not the color image includes white areas, the amount of white ink is the total amount of white ink that constitutes the white layers L12 and L14.

[0106] The CPU 91 determines the amount of occluding ink based on the target data obtained in the processing of S12 (S13). In other words, in this embodiment, the CPU 91 determines the amount of occluding ink based on the amount of white ink, with the amount corresponding to the amount of white ink (S13).

[0107] The amount of shielding ink is the total amount of shielding ink ejected from the shielding head 5 shown in Figures 4 and 5 by a predetermined number of forming processes (S21) described later. In other words, the amount of shielding ink is the total amount of shielding ink that constitutes the shielding layer formed on the film F. In the example in Figure 3, the amount of shielding ink is the total amount of shielding ink that constitutes the shielding layers L13 and L15.

[0108] In this embodiment, in the process of S13, the CPU 91 determines the amount of occluding ink such that the amount of occluding ink increases as the amount of white ink decreases. For example, the amount of second white ink is less than the amount of first white ink. The amount of second occluding ink is greater than the amount of first occluding ink. In this embodiment, when the amount of white ink is the amount of first white ink, the CPU 91 determines the amount of occluding ink to be the amount of first occluding ink. When the amount of white ink is the amount of second white ink, the CPU 91 determines the amount of occluding ink to be the amount of second occluding ink.

[0109] CPU91 may calculate the amount of occluding ink using a mathematical formula, or it may determine the amount of occluding ink using a table.

[0110] The CPU 91 calculates the amount of shielding ink per formation process (S21) (S13). In this embodiment, the CPU 91 uses the amount of shielding ink divided by a predetermined number of times as the amount of shielding ink per formation process. In the example in Figure 3, the amount of shielding ink per formation process is the amount of shielding ink constituting the shielding layer L13, and is equal to the amount of shielding ink constituting the shielding layer L15. Note that the amount of shielding ink per formation process may differ between the shielding layer L13 and the shielding layer L15.

[0111] The CPU 91 identifies the color area R1 and the white area R2 shown in Figure 8 from the print data specified by the print instruction (S14).

[0112] As shown in Figure 8, the color region R1 is the region of film F where the color image is formed. In other words, the color region R1 is the region of film F where the color layer L11 is formed. The white region R2 is the region of film F where the base layer is formed. In other words, the white region R2 is the region of film F where the white layers L12 and L14 are formed.

[0113] Part or all of the color region R1 overlaps with the white region R2 in a planar view. If the entirety of the color region R1 overlaps with the white region R2 in a planar view, the color region R1 may coincide with the white region R2, or it may be positioned inside the white region R2.

[0114] Part or all of the white region R2 overlaps with the color region R1 in a plan view. If the entirety of the white region R2 overlaps with the color region R1 in a plan view, the white region R2 may coincide with the color region R1, or it may be positioned inside the color region R1.

[0115] In the example shown in Figure 8, the entire color region R1 overlaps with a portion of the white region R2 in a plan view. That is, the color region R1 is located inside the white region R2 in a plan view.

[0116] In this embodiment, the print data includes image data. The image data represents an image. The image includes a color image and a background. In the processing of S14, the CPU 91 identifies a color region R1 and a white region R2 based on the image data.

[0117] As shown in Figure 7, the CPU 91 determines the occlusion region R3 based on the color region R1 and white region R2 identified in the S14 process (S15). For example, the CPU 91 identifies the projection region R4 based on the color region R1 and white region R2. The projection region R4 is the region onto which the color region R1 and white region R2 are projected in a plan view. In the example in Figure 8, the entirety of the color region R1 overlaps with the white region R2 in a plan view, so the projection region R4 coincides with the white region R2 in a plan view.

[0118] Although not shown in the diagram, if the entire white region R2 overlaps with the color region R1 in a plan view, then the projected region R4 coincides with the color region R1 in a plan view.

[0119] When a portion of the color region R1 and a portion of the white region R2 overlap in a planar view, the projected region R4 is composed of a non-overlapping color region, a non-overlapping white region, and an overlapping region. The non-overlapping color region is the portion of the color region R1 that does not overlap with the white region R2 in a planar view. The non-overlapping white region is the portion of the white region R2 that does not overlap with the color region R1 in a planar view. The overlapping region is the portion where the color region R1 and the white region R2 overlap.

[0120] The entire occlusion region R3 overlaps with the projection region R4 in a plan view. In other words, in the S15 process, the CPU 91 determines the occlusion region R3 such that the entire occlusion region R3 overlaps with the projection region R4 in a plan view. In this case, the occlusion region R3 may coincide with the projection region R4 in a plan view, or it may be located inside the projection region R4. In other words, the occlusion region R3 is either the region that coincides with the color region R1, the region that coincides with the white region R2, or the region that is inside either the color region R1 or the white region R2. The occlusion region R3 just needs to not extend beyond the projection region R4 in a plan view.

[0121] In the example shown in Figure 8, the occlusion region R3 is located inside the projection region R4 in a plan view.

[0122] CPU91 turns on the white flag in RAM93 (S16). CPU91 turns on the color flag in RAM93 (S16). CPU91 turns on the shielding flag in RAM93 (S16). The white flag, color flag, and shielding flag are stored in RAM93.

[0123] In the following, the operation of transporting the print head 10 in the left-right direction without ejecting ink from the print head 10 will be referred to as "non-ejecting scanning of the print head 10".

[0124] The white flag indicates whether the white head 3 will perform an ejection scan or a non-ejection scan during the formation process (S21) described later. When the white flag is ON, it indicates that the white head 3 will perform an ejection scan. When the white flag is OFF, it indicates that the white head 3 will perform a non-ejection scan.

[0125] Similarly, the color flag indicates whether the color head 4 will perform ejection scanning or non-ejection scanning during the forming process (S21). The shielding flag indicates whether the shielding head 5 will perform ejection scanning or non-ejection scanning during the forming process (S21).

[0126] The CPU 91 performs the forming process (S21). During the forming process, the CPU 91 refers to the color flag, white flag, and shielding flag to determine whether to perform ejection scanning or non-ejection scanning for each head 10.

[0127] In the following, the formation process performed after the S16 process will be referred to as the "first formation process." In the first formation process, the white flag, color flag, and shielding flag are all set to ON by the S16 process. Therefore, the CPU 91 decides to perform the ejection scan of the white head 3, the ejection scan of the color head 4, and the ejection scan of the shielding head 5 in the first formation process.

[0128] In the first forming process, the CPU 91 repeatedly performs parallel scanning of the white head 3, color head 4, and shielding head 5, and sub-scans a predetermined amount of the platen 7 from front to back. The parallel scanning of the white head 3, color head 4, and shielding head 5 is an operation in which the ejection scanning of the white head 3, color head 4, and shielding head 5 are performed in parallel.

[0129] In the first formation process, the CPU 91 ejects the amount of shielding ink calculated in the S13 process for each formation process from the shielding head 5. In other words, the CPU 91 ejects an amount of shielding ink from the shielding head 5 corresponding to the amount of white ink.

[0130] As shown in state ST2 in Figure 3, a color layer L11 is formed on the film F by the first forming process. On the film F, a white layer L12 is formed on the color layer L11. On the film F, a shielding layer L13 is formed on the white layer L12.

[0131] The formation process is carried out by the process S10 shown in Figure 7, with the platen 7 shown in Figure 5 being heated by the heater 70. As a result, the ink layer L1 is formed on the film F placed on the platen 7 heated by the heater 70. In this way, the organic solvent in the ink that has landed on the film F evaporates, and the ink layer L1 is formed on the film F.

[0132] As shown in Figure 8, in this embodiment, in the first formation process, the CPU 91 forms a color layer L11 in the color region R1. The CPU 91 forms a white layer L12 in the white region R2. The CPU 91 forms a shielding layer L13 in the shielding region R3 determined in the process of S15.

[0133] As shown in Figure 7, the CPU 91 determines (S22) whether the number of times the forming process (S21) has been executed has reached a predetermined number. The predetermined number indicates the number of unit sets to be layered on the film F. In other words, the number of unit sets layered on the film F corresponds to the number of times the forming process has been executed.

[0134] The predetermined number of times is not limited to a specific number, as long as there are multiple predetermined numbers. In the example shown in Figure 3, two unit sets are stacked, so the predetermined number of times is 2. The predetermined number of times is stored in advance in the flash memory 92. The predetermined number of times may also be specified by the user via the operation unit 98.

[0135] If the number of times the forming process has been executed has not reached a predetermined number (S22:NO), the CPU 91 performs a transport process (S23). In the transport process, the CPU 91 transports the platen 7 from rear to front to a folding position not shown. When the platen 7 is at the folding position, the rear end of the platen 7 is positioned in front of the front end of the head 10.

[0136] CPU91 turns the color flag OFF (S24). CPU91 turns the white flag ON (S24). CPU91 turns the occlusion flag ON (S24). CPU91 moves processing to S21.

[0137] The CPU 91 performs the formation process (S21). Hereafter, the formation process performed after the process in S24 will be referred to as the "second formation process". In the second formation process, the white flag and the shielding flag are turned ON by the process in S24. Therefore, the CPU 91 decides to perform the ejection scan of the white head 3 and the ejection scan of the shielding head 5 in the second formation process.

[0138] In the second forming process, the color flag is turned OFF by the process in S24. Therefore, the CPU 91 decides to perform a non-ejection scan of the color head 4 in the second forming process.

[0139] In the second forming process, the CPU 91 repeatedly performs parallel scanning of the white head 3 and the shielding head 5, and sub-scans a predetermined amount of the platen 7 from front to back. Parallel scanning of the white head 3 and the shielding head 5 is an operation in which the ejection scanning of the white head 3 and the shielding head 5 are performed in parallel.

[0140] In the second formation process, the CPU 91 ejects the amount of shielding ink calculated in the S13 process for each formation process from the shielding head 5. In other words, the CPU 91 ejects an amount of shielding ink from the shielding head 5 corresponding to the amount of white ink.

[0141] As shown in state ST2 in Figure 3, the second forming process creates a white layer L14 on top of the shielding layer L13 in film F. A shielding layer L15 is then formed on top of the white layer L14 in film F. In other words, in the second forming process, an additional unit set is formed on top of the unit set formed in the first forming process.

[0142] As shown in Figure 8, in this embodiment, in the second formation process, the CPU 91 forms a white layer L14 in the white region R2. The CPU 91 forms a shielding layer L15 in the shielding region R3 determined in the process of S15.

[0143] As shown in Figure 7, in the determination in S22, if the number of times the forming process has been executed reaches a predetermined number (S22: YES), the CPU 91 performs the discharge process (S25). In the transport process, the CPU 91 transports the platen 7 from the rear to the front end position P11 shown in Figures 4 and 5. The CPU 91 returns to the process of S11.

[0144] As described above, in the above embodiment, the printer 21 forms an ink layer L1 on the film F that is transferred to the printing medium M. The color head 4 ejects color ink. The shielding head 5 ejects shielding ink. The color layer L11 is an ink layer L1 composed of color ink and constitutes a color image. The shielding layers L13 and L15 are ink layers L1 composed of shielding ink, respectively.

[0145] The CPU 91 forms a color layer L11 on the film F by ejecting color ink from the color head 4 (S21). On the film F on which the color layer L11 is formed, the CPU 91 forms shielding layers L13 and L15 by ejecting shielding ink from the shielding head 5 onto the color layer L11 (S21).

[0146] According to the formation process in S21, shielding layers L13 and L15 are formed on the color layer L11 of the film F. The film F, on which the ink layer L1 has been formed, proceeds to the powder coating process (S2) and beyond with the shielding layers L13 and L15 on the color layer L11. In this case, according to the above configuration, the printer 21 mainly contributes to the effects described below.

[0147] Referring to Figure 9, the case in which the above-mentioned film F is used and the ink layer L1 is transferred from the film F to the printing medium M in the transfer process (S4) will be explained. In Figure 9, the direction in which the ink layer L1 is formed on the printing medium M is considered upward. In Figure 9, the printing medium M contains dye D. Arrow A1 shows the process of dye D sublimation transfer from the printing medium M to the ink layer L1. Arrow A2 shows the direction in which the user visually inspects the printed result G.

[0148] In the transfer process (S4), when the printing medium M is heated, the dye D is extracted by the organic solvent S in the ink layer L1. This results in the sublimation transfer of the dye D from the printing medium M to the ink layer L1.

[0149] When the ink layer L1 is transferred from the film F to the printing medium M in the transfer process (S4), the shielding layers L13 and L15 are present beneath the color layer L11 on the film F. Therefore, the distance D1 from the printing medium M to the color layer L11 is increased by at least the length of the shielding layers L13 and L15. Thus, the shielding layers L13 and L15 suppress the dye D from reaching the color layer L11 from the printing medium M by sublimation transfer. As a result, the shielding layers L13 and L15 suppress the visibility of the dye D relative to the color layer L11. Therefore, the printer 21 contributes to suppressing a decrease in the quality of the image transferred to the printing medium M.

[0150] Let's assume that the white ink acts as an opacity ink. In this case, the saturation of the white ink is, for example, less than 1. Furthermore, the lightness of the white ink is, for example, greater than 9.

[0151] Therefore, if the saturation of dye D in the printing medium M is higher than the saturation of the white ink, the dye D that has sublimated from the printing medium M to the ink layer L1 may be noticeable. If the brightness of dye D in the printing medium M is lower than the brightness of the white ink, the dye D that has sublimated from the printing medium M to the ink layer L1 may be noticeable. In this case, the dye D that has sublimated from the printing medium M to the ink layer L1 will not be shielded by the white shielding layers L13 and L15.

[0152] On the other hand, in the above embodiment, the shielding ink is an ink of a different color from the white ink. In this case, the shielding layers L13 and L15 shield the dye D that has been sublimated and transferred from the printing medium M to the ink layer L1.

[0153] In the above embodiment, the shielding head 5 ejects black ink as the shielding ink. As a result, the shielding layers L13 and L15 are formed by the black ink. Therefore, the shielding layers L13 and L15 further suppress the visibility of the dye D against the color layer L11. Thus, the printer 21 further contributes to suppressing the deterioration of the image quality transferred to the printing medium M.

[0154] The problems that arise when the white layer L12 is not present in the above embodiment will be explained. In this case, when the user visually inspects the printed result G from the direction indicated by arrow A2, the occlusion layer L13 may be visible through the color layer L11. Therefore, the color development of the color layer L11 may deteriorate.

[0155] In the above embodiment, the white head 3 ejects white ink. The white layers L12 and L14 are ink layers L1 composed of white ink. The CPU 91 forms the white layer L12 on the film F by ejecting white ink from the white head 3 onto the color layer L11 (S21). The CPU 91 forms the shielding layer L13 on the film F by ejecting shielding ink from the shielding head 5 onto the white layer L12.

[0156] According to this, a white layer L12 exists between the shielding layer L13 and the color layer L11. Therefore, when the ink layer L1 is transferred from the film F to the printing medium M, the white layer L12 suppresses the deterioration of the color development of the color layer L11 due to the shielding layer L13. Thus, the printer 21 further contributes to suppressing the deterioration of the image quality transferred to the printing medium M.

[0157] In the above embodiment, a pair of overlapping white layers and shielding layers are considered as a single unit set. The CPU 91 controls the white head 3 and the shielding head 5 to form multiple unit sets on the color layer L11 in the film F (S21).

[0158] According to this, in film F, multiple unit sets exist above the color layer L11. When the ink layer L1 is transferred from film F to the printing medium M in the transfer process (S4), as shown in Figure 9, multiple unit sets exist below the color layer L11 in film F. Therefore, the distance D1 from the printing medium M to the color layer L11 becomes longer by at least the amount of multiple unit sets.

[0159] Therefore, the multiple unit sets suppress the dye D from reaching the color layer L11 from the printing medium M by sublimation transfer. As a result, the multiple unit sets suppress the visibility of dye D against the color layer L11. Thus, the printer 21 further contributes to suppressing the degradation of the image quality transferred to the printing medium M.

[0160] In the above embodiment, the CPU 91 ejects an amount of shielding ink from the shielding head 5 corresponding to the amount of white ink (S21). The amount of white ink corresponds to the sum of the thicknesses of the white layers L12 and L14. Therefore, the printer 21 contributes to changing the sum of the thicknesses of the shielding layers L13 and L15 according to, for example, the sum of the thicknesses of the white layers L12 and L14.

[0161] In the above embodiment, the amount of occluding ink increases as the amount of white ink decreases. Therefore, the printer 21 contributes to ensuring that the sum of the thicknesses of the white layers L12, L14 and the occluding layers L13, L15 is above a certain level. The sum of the thicknesses of the white layers L12, L14 and the occluding layers L13, L15 is the thickness from the white layer L12 to the occluding layer L15. Thus, the printer 21 suppresses the dye D from reaching the color layer L11 from the printing medium M by sublimation transfer. As a result, the printer 21 further contributes to suppressing the deterioration of the image quality transferred to the printing medium M.

[0162] In the above embodiment, the problems that arise when the occlusion layers L13 and L15 extend beyond the projection area R4 in a plan view will be explained. In this case, when the user visually inspects the printed result G from the direction indicated by arrow A2, the occlusion layers L13 and L15 may be visible through the color layer L11 or the white layer L12. Therefore, the degradation of the image quality transferred to the printing medium M may worsen.

[0163] In the above embodiment, the CPU 91 ejects occlusion ink from the occlusion head 5 into the occlusion area R3 (S21). The occlusion area R3 is either the area that coincides with the color area R1, the area that coincides with the white area R2, or the area that is inside either the color area R1 or the white area R2. This prevents the occlusion layers L13 and L15 from extending beyond the projection area R4 in a plan view. That is, it prevents the occlusion layers L13 and L15 from extending beyond the color layer L11 or the white layers L12 and L14 in a plan view. Therefore, the printer 21 further contributes to suppressing the deterioration of the image quality transferred to the printing medium M.

[0164] In the above embodiment, the problems that arise when the ejection scanning of both the color head 4 and the shielding head 5, and the ejection scanning of the white head 3 are not performed in parallel will be explained. In this case, the formation process in which one or both of the color head 4 and the shielding head 5 are ejected will be performed separately from the formation process in which the white head 3 is ejected. Therefore, it will take time to form the ink layer L1 on the film F, which may lead to a decrease in productivity.

[0165] In the above embodiment, the CPU 91 performs parallel scanning of the white head 3, the color head 4, and the shielding head 5 during the first forming process (S21). The CPU 91 performs parallel scanning of the white head 3 and the shielding head 5 during the second forming process (S21). That is, the CPU 91 performs the ejection scanning of the color head 4 and the ejection scanning of the shielding head 5 in parallel with the ejection scanning of the white head 3.

[0166] According to this, the formation process (S21) is performed in a shorter time compared to the case where the ejection scan of the white head 3 is performed separately from the ejection scan of the color head 4 and the shielding head 5. Therefore, the printer 21 contributes to suppressing the deterioration of the quality of the image transferred to the printing medium M while suppressing the deterioration of productivity.

[0167] In the baking process (S3), the ink layer L1 is sandwiched between the powder layer LP and the film F. Therefore, the organic solvent S in the ink layer L1 does not evaporate easily. As mentioned above, the organic solvent S in the ink layer L1 is one of the causes of sublimation transfer. Therefore, in the transfer process (S4), if a large amount of organic solvent S remains in the ink layer L1, a large amount of dye D moves from the printing medium M to the ink layer L1 due to sublimation transfer.

[0168] In the above embodiment, the platen 7 is equipped with a heater 70. The CPU 91 performs the forming process (S21) with the heater 70 heated. During the forming process, the powder layer LP has not yet been formed on the film F. Therefore, the organic solvent S in the ink that has landed on the film F is easily evaporated by the heat transferred from the heater 70 to the film F. Thus, the ink layer L1 is formed on the film F as the organic solvent S in the ink that has landed on the film F evaporates.

[0169] As a result, the amount of organic solvent S remaining in the ink layer L1 during the transfer process (S4) is reduced. Therefore, the amount of dye D that moves from the printing medium M to the ink layer L1 by sublimation transfer is suppressed. Thus, the printer 21 further contributes to suppressing the deterioration of the image quality transferred to the printing medium M.

[0170] In the above embodiment, the printing medium M corresponds to the "printing medium" of the present invention. The ink layer L1 corresponds to the "ink layer" of the present invention. The film F corresponds to the "film" of the present invention. The printer 21 corresponds to the "image forming apparatus" of the present invention.

[0171] Color head 4 corresponds to the "color head" of the present invention. Shielding head 5 corresponds to the "shielding head" of the present invention. CPU 91 corresponds to the "control unit" and "computer" of the present invention. Color layer L11 corresponds to the "color layer" of the present invention. Shielding layers L13 and L15 correspond to the "shielding layers" of the present invention.

[0172] White head 3 corresponds to the "white head" of the present invention. White layers L12 and L14 correspond to the "white layers" of the present invention. The ejection scan of color head 4 corresponds to the "color scan" of the present invention. The ejection scan of white head 3 corresponds to the "white scan" of the present invention. The ejection scan of shielding head 5 corresponds to the "shielding scan" of the present invention.

[0173] Platen 7 corresponds to the "heat platen" of the present invention.

[0174] The present invention may be modified in various ways from the above embodiments. The modifications described below may be combined with each other to the extent that they do not create contradictions.

[0175] In the above embodiment, the CPU 91 ejects an amount of shielding ink from the shielding head 5 corresponding to the amount of white ink during the forming process (S21). Alternatively, the CPU 91 may eject an amount of shielding ink from the shielding head 5 corresponding to other parameters. Various modifications with respect to other parameters will be described below.

[0176] The CPU 91 may, during the forming process, eject an amount of shielding ink from the shielding head 5 according to the type of film F. In this case, the CPU 91 acquires target data in the S12 process, and the target data should indicate the type of film F. In the S13 process, the CPU 91 may determine the amount of shielding ink according to the type of film F based on the acquired target data.

[0177] The type of film F may be determined by the material of the receiving layer F2. The type of film F may be determined by the thickness of the receiving layer F2. The type of film F may be determined by the amount of ink fixed to the receiving layer F2. The type of film F may be determined by other factors relating to film F.

[0178] For example, the thicker the receiving layer F2, the greater the amount of polyvalent metal salt contained in the receiving layer F2. The greater the amount of polyvalent metal salt contained in the receiving layer F2, the more easily the receiving layer F2 causes the ink to aggregate. For this reason, the CPU 91 may determine the amount of shielding ink such that, for example, the amount of shielding ink increases as the amount of polyvalent metal salt contained in the receiving layer F2 increases. In this way, the printer 21 contributes to forming shielding layers L13 and L15 of a thickness suitable for the type of film F. The CPU 91 may also determine the amount of shielding ink such that the amount of shielding ink decreases as the amount of polyvalent metal salt contained in the receiving layer F2 increases.

[0179] The CPU 91 may, during the formation process, eject a quantity of shielding ink from the shielding head 5 corresponding to the temperature set in the transfer step (S4). The temperature set in the transfer step (S4) is, for example, the heating temperature of the heat press machine 23.

[0180] The CPU 91 may, during the forming process, discharge an amount of shielding ink from the shielding head 5 in proportion to the pressure set in the transfer step (S4). The pressure set in the transfer step (S4) is, for example, the pressure applied to the film F and the printing medium M by the heat press machine 23.

[0181] The CPU 91 may, during the forming process, eject an amount of shielding ink from the shielding head 5 corresponding to the time set in the transfer step (S4). The time set in the transfer step (S4) is, for example, the time for which pressure is applied to the film F and the printing medium M by the heat press machine 23 or the heating time by the heat press machine 23.

[0182] In these cases, the CPU 91 acquires the target data in the S12 process, and the target data may indicate the temperature, pressure, or time set in the transfer process (S4). In the S13 process, the CPU 91 may determine the amount of shielding ink based on the acquired target data, according to the temperature, pressure, or time set in the transfer process (S4).

[0183] For example, the higher the temperature set in the transfer process (S4), the more likely sublimation transfer will occur in the transfer process (S4). The higher the pressure set in the transfer process (S4), the more likely sublimation transfer will occur in the transfer process (S4). The longer the time set in the transfer process (S4), the more likely sublimation transfer will occur in the transfer process (S4).

[0184] In the S13 process, the CPU 91 may determine the amount of shielding ink such that the amount of shielding ink increases as sublimation transfer is more likely to occur. In this way, the printer 21 contributes to forming shielding layers L13 and L15 of appropriate thickness for the temperature, pressure, or time in the transfer process (S4). Alternatively, in the S13 process, the CPU 91 may determine the amount of shielding ink such that the amount of shielding ink decreases as sublimation transfer is more likely to occur.

[0185] The CPU 91 may eject an amount of shielding ink from the shielding head 5 according to the type of printing medium M. In this case, the CPU 91 acquires target data in the S12 process, and the target data should indicate the type of printing medium M. In the S13 process, the CPU 91 may determine the amount of shielding ink according to the type of printing medium M based on the acquired target data.

[0186] The type of printing medium M may be determined by the material of the printing medium M. The type of printing medium M may also be determined by the thickness of the printing medium M.

[0187] The type of printing medium M may be determined by the lightness of the printing medium M. The type of printing medium M may be determined by the saturation of the printing medium M. The type of printing medium M may be determined by the hue of the printing medium M. The type of printing medium M may be determined by other factors relating to the printing medium M.

[0188] For example, the lower the brightness of the printing medium M, the more likely sublimation transfer is to occur in the transfer process (S4). Therefore, the CPU 91 may determine the amount of shielding ink so that, for example, the lower the brightness of the printing medium M, the greater the amount of shielding ink. The higher the saturation of the printing medium M, the more likely sublimation transfer is to occur in the transfer process (S4). Therefore, the CPU 91 may determine the amount of shielding ink so that, for example, the higher the saturation of the printing medium M, the greater the amount of shielding ink. In this way, the printer 21 contributes to forming shielding layers L13 and L15 of appropriate thickness for the type of printing medium M.

[0189] The CPU 91 may determine the amount of occluding ink such that, for example, the lower the brightness of the printing medium M, the less occluding ink is needed. The CPU 91 may also determine the amount of occluding ink such that, for example, the higher the saturation of the printing medium M, the less occluding ink is needed.

[0190] The CPU 91 may, during the formation process, eject an amount of shielding ink from the shielding head 5 according to a setting value specified by the user. In this case, the user may specify the setting value via the operation unit 98. For example, the user may specify the setting value such that the amount of shielding ink increases as the desired image quality increases. In this way, the printer 21 contributes to forming the shielding layers L13 and L15 according to the image quality requested by the user, for example.

[0191] The following describes variations other than parameters. In the above embodiment, the CPU 91 determines the amount of occluding ink in the S13 process such that the amount of occluding ink increases as the amount of white ink decreases. Alternatively, the CPU 91 may determine the amount of occluding ink such that the amount of occluding ink decreases as the amount of white ink decreases.

[0192] The shielding layers L13 and L15 may have complementary colors to the colors of the printing medium M. In this case, the shielding ink may have complementary colors to the colors of the printing medium M. The shielding ink may be composed of color inks. That is, the shielding ink may be changed from black ink. When the shielding ink is composed of color inks, the complementary colored shielding layers L13 and L15 may be formed by multiple color inks.

[0193] For example, if sublimation transfer occurs during the transfer process (S2), the color of dye D mixes with the colors of the shielding layers L13 and L15. If the shielding layers L13 and L15 have complementary colors, the saturation and brightness of the mixed color will be lower. As a result, the shielding layers L13 and L15 further suppress the visibility of dye D against the color layer L11. Therefore, the printer 21 further contributes to suppressing the deterioration of the image quality transferred to the printing medium M.

[0194] The multiple heads 10 may be modified from those in the above embodiment. For example, the multiple heads 10 may be line heads fixed to the frame of the printer 21. The arrangement of the multiple heads 10 in the front-to-back direction may be modified from those in the above embodiment. The multiple heads 10 may also be arranged in the left-to-right direction.

[0195] The number of heads 10 may be one, two, or four or more. For example, let's explain the case where the number of heads 10 is four or more. When only the three heads 10, the white head 3, the color head 4, and the shielding head 5, are ejected and scanned, this corresponds to parallel scanning of the white head 3, the color head 4, and the shielding head 5 in the molding process. Furthermore, when the ejection scanning of other heads 10 is performed in parallel with the white head 3, the color head 4, and the shielding head 5, this also corresponds to parallel scanning of the white head 3, the color head 4, and the shielding head 5 in the molding process.

[0196] Multiple heads 10 may omit the white head 3. In this case, the white layer L12 does not need to be formed on the film F.

[0197] Multiple heads 10 may omit the shielding head 5. In this case, the color head 4 may function as the shielding head. That is, the shielding ink may be color ink. For example, the black ink used for color ink may be used as the shielding ink. In this case, a single container common to both the black ink container and the shielding ink container is used.

[0198] The CPU 91 can form the color layer L11 and the shielding layer L13 on the film F in the order of color layer L11 and shielding layer L13 from the film F. Preferably, the CPU 91 can form the color layer L11, the white layer L12, and the shielding layer L13 on the film F in the order of color layer L11, white layer L12, and shielding layer L13 from the film F. The manner in which the ink layer L1 is formed by the formation process (S21) may be appropriately changed as follows, for example.

[0199] In the above embodiment, the CPU 91 stacks multiple unit sets. Alternatively, the CPU 91 may form a single unit set. In this case, the CPU 91 may omit the processing of S22, S23, and S24.

[0200] In the first forming process, the CPU 91 performs parallel scanning of the white head 3, the color head 4, and the shielding head 5. Alternatively, in the first forming process, the CPU 91 may perform parallel scanning of the white head 3 and the color head 4, and also perform a non-ejecting scan of the shielding head 5. Parallel scanning of the white head 3 and the color head 4 is an operation in which the ejecting scans of the white head 3 and the color head 4 are performed in parallel. In this case, in the process of S16, the CPU 91 may turn OFF the shielding flag. After the first forming process, the CPU 91 may turn OFF the color flag and the white flag, and turn ON the shielding flag, and then perform the forming process.

[0201] The CPU 91 may perform an ejection scan of the color head 4 and a non-ejection scan of the white head 3 and the shielding head 5 during the first forming process. In this case, the CPU 91 may turn OFF the shielding flag and the white flag during the S16 process. After the first forming process, the CPU 91 may turn OFF the color flag and ON the white flag and the shielding flag, and then perform the forming process. In this case, the sub-scanning of the platen 7 by a predetermined amount may be performed from front to back.

[0202] Alternatively, instead of turning the color flag OFF and the white and occlusion flags ON after the first forming process, the CPU 91 may control it as follows: that is, the CPU 91 may perform the forming process with the color and occlusion flags OFF and the white flag ON. After that, the CPU 91 may perform the forming process with the color and white flags OFF and the occlusion flag ON.

[0203] In the above embodiment, the shielding region R3 is either the same as the projection region R4 in a plan view, or it is a region inside the projection region R4. In contrast, a portion of the shielding region R3 does not need to overlap with the projection region R4 in a plan view. That is, the shielding layers L13 and L15 may extend beyond any of the white layers L12 and L14 and the color layer L11 in a plan view.

[0204] In the above embodiment, in DTF printing, a transfer solution application step may be performed instead of the powder application step (S2). In this case, the multiple heads 10 may include transfer heads. The transfer heads discharge the transfer solution onto the ink layer L1 on the film F. The transfer solution constitutes an adhesive layer. The adhesive layer is interposed between the ink layer L1 and the printing medium M in the transfer step (S4) to improve the adhesion of the ink layer L1 to the printing medium M.

[0205] If a transfer solution is used, a drying step may be performed instead of the baking step (S3). In the drying step, the transfer solution is dried with hot air.

[0206] In the above embodiment, the powder coating step may be omitted in DTF printing. In this case, the transfer solution coating step may also be omitted. In other words, a powder layer LP may not be formed on the film F.

[0207] If a powder layer LP is not formed on the film F, for example, in the image forming process (S1), it is preferable that the ink layer L1 formed as the uppermost layer contains a component with adhesive properties. In other words, it is preferable that the ink forming the uppermost layer contains a component with adhesive properties. The uppermost layer is the layer of the ink layer L1 furthest from the film F. For example, if the uppermost layer is a white layer, it is preferable that the white ink contains a component with adhesive properties.

[0208] In the above embodiment, the CPU 91 acquires target data from the print data during processing S12. Alternatively, the user may operate the operation unit 98 and input the target data to the printer 21. The CPU 91 may acquire the target data input by the user via the operation unit 98. Thus, the method of acquiring the target data may be changed from the above embodiment.

[0209] In the above embodiment, the organic solvent in the white ink may have a stronger ability to suppress the movement of dye D within the layers than the organic solvent in the shielding ink. In this case, for example, white ink may be further dispensed onto the shielding layer L15, forming a white layer on top. This white layer on top further contributes to suppressing the visibility of dye D in the ink layer L1 due to sublimation transfer.

[0210] In the above embodiment, "the second layer is formed on the first layer" does not exclude the case where the second layer is formed on the first layer via another layer. That is, "the second layer is formed on the first layer" includes the case where the second layer is formed directly on the first layer and the case where the second layer is formed on the first layer via another layer. For example, "the shielding layer L13 is formed on the color layer L11" means that, as in the above embodiment, the shielding layer L13 may be formed on the color layer L11 via the white layer L12. On the other hand, the shielding layer L13 may be formed directly on the color layer L11. Furthermore, the shielding layer L13 may be formed on the color layer L11 via the white layer L12 and another layer.

[0211] In the above embodiment, a specific layer may be formed between one set of units and another set of units. The specific layer is, for example, a color layer. In the image forming step (S1), the top layer may be changed from the occlusion layer. The top layer may be a white layer or a color layer.

[0212] If the uppermost layer is a layer other than the shielding layer, the shielding flag should be turned OFF in the S24 process when the final forming process (S21) is performed. The final forming process is performed when the S22 decision determines that the number of times the forming process is to be executed is "a predetermined number - 1".

[0213] In the above embodiment, the heater 70 is connected to the CPU 91. However, the heater 70 does not have to be connected to the CPU 91. That is, the heater 70 does not have to be controlled by the CPU 91. In this case, for example, the user may turn on the power to the heater 70 and allow the heater 70 to heat up before performing the print start operation.

[0214] In the above embodiment, the timing at which the CPU 91 heats the heater 70 is not limited to before the print instruction is received. The CPU 91 may heat the heater 70 after receiving the print instruction. It is preferable that the CPU 91 raises the heater 70 to the set heating temperature before the forming process (S21).

[0215] In the above embodiment, the platen 7 may omit the heater 70. In other words, the platen 7 does not have to be a heated platen.

[0216] Instead of the CPU91, a microcomputer, ASIC (Application Specific Integrated Circuits), FPGA (Field Programmable Gate Array), etc., may be used as the processor. The main processing may be distributed among multiple processors.

[0217] Non-temporary storage media such as flash memory 92 can be any storage medium capable of retaining information regardless of the storage period. Non-temporary storage media do not necessarily have to include temporary storage media (e.g., transmitted signals). The control program may be downloaded, for example, from a server connected to a network (not shown), i.e., transmitted as a transmission signal, and stored in flash memory 92. In this case, the control program only needs to be stored on a non-temporary storage medium such as an HDD provided in the server. [Explanation of Symbols]

[0218] 3 White Head 4 color heads 5 Shielding head 21 Printers 91 CPU F Film L1 Ink Layer L11 Color Layer L12, L14 white layer L13 and L15 shading layers M Print Media

Claims

1. An image forming apparatus for forming an ink layer on a film that is transferred to a printing medium, A color head that ejects color ink, A shielding head that ejects shielding ink, Control unit and Equipped with, The control unit, By ejecting the color ink from the color head onto the film, a color layer, which is composed of the color ink and constitutes an image, is formed on the film. In the film on which the color layer is formed, the shielding ink is ejected from the shielding head onto the color layer to form a shielding layer which is composed of the shielding ink and is the ink layer. An image forming apparatus characterized by the following.

2. The shielding head ejects black ink as the shielding ink. The image forming apparatus according to claim 1, characterized by the following:

3. Equipped with a white print head that ejects white ink, The control unit, In the film on which the color layer is formed, the white ink is ejected from the white head onto the color layer to form a white layer which is composed of the white ink and is the ink layer. In the film on which the white layer is formed, the shielding layer is formed by ejecting the shielding ink onto the white layer from the shielding head. The image forming apparatus according to claim 1, characterized by the following:

4. The control unit, Controlling the white head and the shielding head, and forming a plurality of the white layer and the shielding layer as a single unit set on the color layer in the film on which the color layer is formed. The image forming apparatus according to claim 3, characterized by the following:

5. The control unit, Discharge from the shielding head an amount of shielding ink corresponding to the amount of white ink discharged by the white head. The image forming apparatus according to claim 3, characterized by the following:

6. The control unit, Discharge the shielding ink from the shielding head in an amount corresponding to the type of film. The image forming apparatus according to claim 1, characterized by the following:

7. The control unit, In the transfer process performed when transferring the aforementioned image from the film to the printing medium, an amount of the shielding ink corresponding to the temperature, pressure, or time set in the transfer process is ejected from the shielding head. The image forming apparatus according to claim 1, characterized by the following:

8. The control unit, The shielding ink is ejected from the shielding head in an amount corresponding to the type of printing medium on which the image is transferred from the film. The image forming apparatus according to claim 1, characterized by the following:

9. The control unit, Discharge the shielding ink from the shielding head in an amount corresponding to a setting value specified by the user. The image forming apparatus according to claim 1, characterized by the following:

10. The control unit, Discharge the shielding ink from the shielding head into either the area where the color layer is formed, the area where the white layer is formed, or an area inside either the color area or the white area. The image forming apparatus according to claim 3, characterized by the following:

11. The control unit, In the film on which the color layer is formed, the shielding ink is ejected from the shielding head onto the color layer to form the shielding layer having a complementary color to the color of the printing medium on which the image is transferred from the film. The image forming apparatus according to claim 1, characterized by the following:

12. The control unit, Alternatively, a color scan, in which the color ink is ejected from the color head while scanning, and a white scan, in which the white ink is ejected from the white head while scanning, can be performed in parallel. Either perform the shielding scan, in which the shielding ink is ejected from the shielding head while scanning, and the white scan in parallel, Alternatively, the color scan, the occlusion scan, and the white scan may be performed in parallel. The image forming apparatus according to claim 3, characterized by the following:

13. The aforementioned film is placed on a heat platen equipped with a heater, The control unit, The color layer is formed on the film by discharging the color ink from the color head onto the film placed on the heat platen heated by the heater. In the film, which is placed on the heat platen heated by the heater and has the color layer formed on it, the shielding layer is formed by discharging the shielding ink onto the color layer from the shielding head. The image forming apparatus according to claim 1, characterized by the following:

14. An image forming method for forming an ink layer on a film that is transferred to a printing medium, By ejecting the color ink from a color head that ejects color ink onto the film, a color layer is formed on the film that is composed of the color ink, constitutes an image, and is the ink layer. In the film on which the color layer is formed, the shielding ink is ejected onto the color layer from a shielding head that ejects the shielding ink, thereby forming a shielding layer which is composed of the shielding ink and is the ink layer. An image formation method characterized by the following.

15. An image forming program for forming an ink layer on a film that is transferred to a printing medium, On the computer, By ejecting the color ink from a color head that ejects color ink onto the film, a color layer is formed on the film, which is composed of the color ink and constitutes an image, and which is the ink layer. In the film on which the color layer is formed, the shielding ink is ejected onto the color layer from a shielding head that ejects the shielding ink, thereby forming a shielding layer which is composed of the shielding ink and is the ink layer. An image forming program characterized by the following.

Images