Printing data creation device, transfer system, printing data creation method, and program

Abstract

The present invention creates printing data that enables overprinting with reduced protrusion of white ink.　An image processing unit 38 creates dot data that indicates an ink discharge position on a medium M, for each color of ink which is used in a printer 2 and on the basis of image data ID. A white plate creation unit 34 adjusts a white printing area WPA on the basis of the image data ID when white ink is overprinted on an image that has been printed in color ink. An area determination unit 35 of the white plate creation unit 34 determines a color printing area CPA in the image data ID. A contour extraction unit 36 extracts pixels P that constitute the contour of the color printing area CPA. A pixel adjustment unit 37 adjusts the color printing area CPA on the basis of the pixels P that constitute the contour, and determines the white printing area WPA.

Description

Printing data creation device, transfer system, printing data creation method, and program

[0001] The present invention relates to a printing data creation device, a transfer system, a printing data creation method, and a program.

[0002] DTF (Direct to Film) is one of the transfer methods. In DTF, an image is printed on a film by a printer, and an adhesive is applied to the image. By overlapping the printed surface of the film on the work and performing hot pressing, the image to which the adhesive is applied adheres to the work. After hot pressing, the film is peeled off from the work, and the image is transferred to the work (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2019-171840

[0004] When the work is dark or transparent, the color of the image transferred to the work may not be properly visible. In order to improve the visibility of the image, the printer may print a white ink over the image. In the work after transfer, the white ink is on the lower side of the image and functions as a light reflection layer. As a result, even on a dark or transparent work, the color of the transferred image can be properly visible.

[0005] The printing data creation device creates printing data for printing an image by a printer based on the image data. The printing data includes dot data indicating the ejection positions of the inks on the medium. When performing overprinting of white ink, the printing data creation device creates printing data including dot data of color inks constituting the image and dot data of white ink.

[0006] Here, since the white ink functions as a light reflection layer, the ejection amount at each dot tends to be larger than that of the color ink. Therefore, on the work after transfer, there is a possibility that the white ink may protrude from the outline of the image.

[0007] In the printing data creation device, it is required to create printing data capable of reducing the protrusion of white ink in overprinting.

[0008] A print data creation device in one aspect of the present invention is a print data creation device that creates print data for printing an image on a medium using a printing device, comprising: a dot data creation unit that creates dot data indicating the ink ejection position on the medium for each color of ink used by the printing device, based on image data, as the print data; and an area adjustment unit that adjusts the printing area of ​​the white ink based on the image data when performing overprinting, in which white ink is printed on top of the image printed with color ink, wherein the area adjustment unit comprises: an area determination unit that determines the printing area of ​​the color ink shown in the image data; an outline extraction unit that extracts pixels constituting the outline of the printing area of ​​the color ink; and a pixel adjustment unit that determines the printing area of ​​the white ink by adjusting the printing area of ​​the color ink based on the pixels constituting the outline, wherein the dot data creation unit creates dot data for the white ink in addition to the dot data for the color ink based on the image data and the printing area of ​​the white ink.

[0009] (2) In the print data creation apparatus of (1) above, the pixel adjustment unit sets the area obtained by excluding the pixels constituting the outline from the print area of ​​the color ink as the print area of ​​the white ink.

[0010] (3) In the print data creation apparatus of (2) above, if there is a non-printing area within the print area of ​​the color ink, the contour extraction unit extracts pixels surrounding the non-printing area within the print area of ​​the color ink, and the pixel adjustment unit sets the area obtained by excluding the pixels constituting the contour and the pixels surrounding the non-printing area from the print area of ​​the color ink as the print area of ​​the white ink.

[0011] (4) In the print data creation apparatus of (2) or (3) above, the pixel adjustment unit sets the area obtained by excluding the pixels extracted by the contour extraction unit from the print area of ​​the color ink as the first print area of ​​the white ink, and the area consisting of the pixels extracted by the contour extraction unit as the second print area of ​​the white ink, which is printed with a smaller ejection amount than the first print area.

[0012] (5) In the print data creation apparatus of (2) or (3) above, the pixel adjustment unit sets the area obtained by excluding the pixels extracted by the contour extraction unit from the print area of ​​the color ink as the print area of ​​the white ink, and the area consisting of the pixels extracted by the contour extraction unit as the print area of ​​the transparent ink.

[0013] (6) In the print data creation apparatus of (2) or (3) above, the pixel adjustment unit sets the area obtained by excluding the pixels extracted by the contour extraction unit from the print area of ​​the color ink as the print area of ​​the white ink, and if there is a narrow part in the print area of ​​the white ink, the pixel adjustment unit incorporates at least a portion of the pixels surrounding the narrow part from the excluded area into the narrow part.

[0014] (7) In the print data creation apparatus of (6) above, the pixel adjustment unit sets the pixels constituting the narrow portion to an area in which white ink is printed with an ejection amount less than the set ejection amount, or an area in which transparent ink is printed.

[0015] (8) A transfer system including any of the print data creation devices described in (1) to (7) above, comprising: a printing device that prints the image on the medium with the color ink and prints the white ink on top of the image based on the print data created by the print data creation device; an adhesive application device that applies adhesive to the white ink printed on the medium; and a pressing device that transfers the image to which the adhesive has been applied to the workpiece by pressing the printed surface of the medium onto the workpiece.

[0016] A method for creating print data in one aspect of the present invention is (9) a method for creating print data for printing an image on a medium using a printing device, comprising: a dot data creation process that creates dot data indicating the ink ejection position on the medium for each color of ink used in the printing device, based on image data, as the print data; and an adjustment process that adjusts the printing area of ​​the white ink based on the image data when performing overprinting, in which white ink is printed on top of an image printed with color ink, wherein the adjustment process comprises: an area determination process that determines the printing area of ​​the color ink shown in the image data; an outline extraction process that extracts pixels constituting the outline of the printing area of ​​the color ink; and a pixel adjustment process that determines the printing area of ​​the white ink by adjusting the printing area of ​​the color ink based on the pixels constituting the outline, wherein in the dot data creation process, dot data for the white ink is created in addition to the dot data for the color ink based on the image data and the printing area of ​​the white ink.

[0017] A program in one aspect of the present invention is (10) a program for creating print data for printing an image on a medium using a printing device, the program causing a computer to perform: a dot data creation process which creates dot data indicating the ink ejection position on the medium for each color of ink used in the printing device, based on image data, as the print data; and an adjustment process which adjusts the printing area of ​​the white ink based on the image data when performing overprinting, in which white ink is printed on top of an image printed with color ink, the adjustment process which includes: an area determination process which determines the printing area of ​​the color ink shown in the image data; an outline extraction process which extracts pixels that constitute the outline of the printing area of ​​the color ink; and a pixel adjustment process which adjusts the printing area of ​​the color ink based on the pixels that constitute the outline to determine the printing area of ​​the white ink, the program which, in the dot data creation process, creates white ink dot data in addition to the color ink dot data based on the image data and the white ink printing area.

[0018] According to the present invention, it is possible to create print data that enables overprinting with reduced white ink bleeding.

[0019] This is a diagram showing an example of the configuration of a transfer system. This is a schematic diagram illustrating the process performed by the transfer system. This is a diagram showing the hardware configuration of the control device. This is a diagram showing the functional configuration of the control device. This is a diagram illustrating the operation of white ink overprinting. (a) is a diagram showing white plate image data created without performing pixel adjustment processing on image data. (b) is a diagram showing white plate image data created by performing pixel adjustment processing on image data. (a) is a diagram illustrating the processing mode of the area determination unit, and (b) is a diagram illustrating the processing mode of the contour extraction unit and the pixel adjustment unit. This is a flowchart showing the processing flow of the print data creation unit when white ink overprinting is set as a printing condition. (a) is a diagram showing the processing mode of the contour extraction unit and the pixel adjustment unit according to Modification 1. (b) is a diagram showing an example of setting the density of white ink and the dot size in the first print area and the second print area. This is a diagram showing the processing mode of the pixel adjustment unit according to Modification 2. This is a diagram showing the processing mode of the pixel adjustment unit according to Modification 3.

[0020] Embodiments of the present invention will be described below with reference to the drawings. In the embodiments, an example in which a print data creation device is applied to a transfer system will be described. Figure 1 is a diagram showing an example of the configuration of the transfer system 1. Figure 2 is a schematic diagram illustrating the process performed by the transfer system 1. Although Figure 2 is a cross-sectional view, the white ink layer WHL and the receiving layer RL of the media M are shown without hatching. Figure 2(a) shows the process of printing an image onto the media M. Figure 2(b) shows the process of forming an adhesive layer AL on the image. Figure 2(c) shows the process of pressing the media M and the workpiece WK. Figure 2(d) shows the process of peeling the media M from the workpiece WK.

[0021] As shown in Figure 1, the transfer system 1 includes, for example, a printer 2 (printing device), a control device 3 for the printer 2 (print data creation device), a shaker 4 (adhesive application device), and a heat press 8 (pressing device). The X, Y, and Z directions shown in Figure 1 are for illustrating an example of the positional relationship between the printer 2 and the shaker 4. The Z direction is along the vertical direction (direction of gravity), which is the vertical direction on the paper in Figure 1. The X and Y directions are along the horizontal direction, which is perpendicular to the Z direction. Note that the thickness of the media M in the heat press 8 in Figure 1 is exaggerated in the illustration.

[0022] In the transfer system 1, for example, an image can be transferred to a workpiece WK using a transfer method called DTF (Direct to Film) to manufacture printed materials. In DTF, an image printed on media M is transferred to the workpiece WK. Specifically, as shown in Figure 1, an image is printed on media M by printer 2. Shaker 4 applies hot melt powder HP (adhesive) to the image printed on media M. Shaker 4 also heats media M, melting the hot melt powder HP applied to the image, thereby forming an adhesive layer AL (see Figure 2(b)) on the image. Next, media M with the printed image is placed on top of workpiece WK and heated and pressed by hot press machine 8. As a result, the image with the formed adhesive layer AL adheres to workpiece WK. After pressing, media M is peeled off workpiece WK, transferring the image to workpiece WK.

[0023] As shown in Figure 2(a), the media M can be, for example, a resin film in which an ink receiving layer RL is formed on a substrate BM. Alternatively, a media M other than film, such as paper, may be used, as long as it is treated to allow the ink to be peeled off after transfer. The workpiece WK can be made from various materials such as cotton, polyester, nylon fabrics, leather, nonwoven fabrics, wood, metal plates, or a combination of at least some of these materials. The workpiece WK can be, for example, clothing such as T-shirts, or fabric products such as tapestries and banners, processed from these materials.

[0024] As shown in Figure 1, the printer 2 can be, for example, an inkjet printer that prints by ejecting droplet-shaped ink from nozzles 23. In Figure 1, as an example, a printer 2 is shown that prints while unwinding a roll of media M and transporting it in the X direction. The printer 2 comprises a platen 21 that supports the media M, and a head 22 that is provided opposite the platen 21 in the Z direction and ejects ink onto the media M supported by the platen 21. The head 22 is provided with a gap between it and the upper surface of the platen 21. Multiple nozzles 23, which are ink ejection ports, are provided on the lower surface of the head 22 that faces the platen 21. The head 22 is movable in the Y direction by a moving mechanism (not shown).

[0025] A shaft 24 is provided on the X1 side of the platen 21, which is rotatable about an axis Y1 along the Y direction. Media M is wound in a roll shape and supported on the outer circumference of the shaft 24. When media M is fed to the X2 side by a dispensing mechanism (not shown), the shaft 24 rotates clockwise about the axis Y1 to unwind the media M. The media M is wound around the upper surface of the platen 21 in a direction that crosses the X direction. Ink is ejected from the nozzle 23 of the head 22 onto the media M located on the upper surface of the platen 21.

[0026] Although detailed illustrations are omitted, the print head 22 of printer 2 is equipped with a nozzle row consisting of multiple nozzles 23, and each nozzle row can be configured to eject different types of ink. The ink used in printer 2 is not limited to a specific type, but water-based ink can be used in DTF. The ink can be, for example, an ink containing a pigment, which is a coloring agent. Inks containing pigments can be, for example, process color inks of C (cyan), M (magenta), Y (yellow), and K (black) (hereinafter referred to as "color inks") or white ink. White ink can contain a colorless or white coloring agent as the coloring agent of the ink and can be an ink having a light-reflective pigment. Alternatively, the ink can be a clear ink (transparent ink) that does not contain a coloring agent such as a pigment or dye.

[0027] Figure 2(a) shows an example in which an image to be transferred to the workpiece WK is printed on media M using color ink, and white ink is printed on top of the image. In this case, a color ink layer COL is formed on the surface of media M, and a white ink layer WHL is formed on top of the color ink layer COL. The color ink layer COL and the white ink layer WHL are collectively referred to as the "ink layer IL".

[0028] As shown in Figure 1, the media M after the printing process is complete is fed out from the platen 21 by a feeding mechanism (not shown) and carried into the shaker 4 located on the X2 side of the printer 2. Although Figure 1 shows a printer 2 corresponding to a roll-shaped media M, the printer 2 may also print on, for example, a sheet-shaped or board-shaped media M. In this case, the printer 2 may include a flat table type platen 21 and a moving mechanism that moves the head 22 relative to the platen 21 in the X and Y directions.

[0029] As shown in Figure 1, the shaker 4 includes a dispensing unit 41 for applying hot melt powder HP to the media M, a heating unit 44 for heating the media M to which the hot melt powder HP has been applied, and a winding unit 47 for winding the dried media M into a roll. The dispensing unit 41, heating unit 44, and winding unit 47 are arranged in the order of dispensing unit 41, heating unit 44, and winding unit 47 from the X1 side to the X2 side in the X direction. The winding unit 47 includes a shaft 48 arranged along the Y direction and a motor (not shown) for rotating the shaft 48 about an axis Y2 along the Y direction. The media M is wound into a roll and supported on the outer circumference of the shaft 48. As the motor drives the shaft 48 to rotate counterclockwise about the axis Y2, the media M fed from the printer 2 is transported to the X2 side in the X direction, passes through the dispensing unit 41 and heating unit 44, and is wound onto the outer circumference of the shaft 48.

[0030] As shown in Figure 1, a support portion 45 for supporting the media M is provided on the lower side in the Z direction of the heating portion 44 of the shaker 4. A recess Mb for the media M is formed on the lower side in the Z direction of the dispensing portion 41 of the shaker 4. When the media M is loaded into the shaker 4, it hangs down in the Z direction due to its own weight between the platen 21 of the printer 2 and the support portion 45 provided on the lower side in the Z direction of the heating portion 44, thereby forming the recess Mb. The recess Mb is formed in a position that overlaps with the dispensing portion 41 when viewed from the Z direction.

[0031] The application unit 41 can be composed of, for example, a nozzle that sprays hot melt powder HP. The application unit 41 supplies hot melt powder HP to the recess Mb of the media M located below. As a result, the hot melt powder HP supplied from the application unit 41 accumulates in the recess Mb. When the media M passes through the recess Mb, it comes into contact with the hot melt powder HP accumulated in the recess Mb. The hot melt powder HP comes into contact with the ink that makes up the image printed on the media M. Since the media M is directly transported from the printer 2 to the shaker 4, the ink printed on the media M is not completely dry, and moisture remains on the surface. Therefore, the hot melt powder HP that comes into contact with the ink adheres to the ink.

[0032] A vibration mechanism 45a is built into the support portion 45 located on the X2 side of the application portion 41. Since the media M is supported by the support portion 45, the vibration of the vibration mechanism 45a is transmitted to the entire media M being transported by the shaker 4 via the support portion 45. The vibration of the media M causes the hot melt powder HP to move on the media M, making it easier for it to adhere to the ink. In addition, the vibration of the media M allows any excess hot melt powder HP that is not adhering to the ink to fall off the media M.

[0033] Hot melt powder HP can be any known type used for DTF. Suitable hot melt powder HP may include, for example, resin powders containing urethane, acrylic, polyester, polyamide, or mixtures thereof. Alternatively, hot melt powder HP may be primarily composed of a thermoplastic polymer and may not contain water or organic solvents. Hot melt powder HP that is solid at room temperature and melts and becomes tacky when heated can be used. Instead of providing an application unit 41 such as a spray nozzle, the user may manually supply the hot melt powder HP to the recesses Mb of the media M.

[0034] As shown in Figure 1, the heating unit 44 includes a heater 46 for heating the media M. By heating the media M, the heater 46 dries any ink that was not yet dry and melts and fixes the hot melt powder HP attached to the ink. Furthermore, the hot melt powder HP becomes adhesive when melted. As a result, as shown in Figure 2(b), an adhesive layer AL is formed on the upper side of the ink layer IL formed on the surface of the media M.

[0035] In Figure 1, the shaker 4 is shown as an example in which a heater 46, which is a mechanism for heating the media M, is integrated into the shaker 4. However, a separate mechanism for heating the media M may also be provided. For example, if the media M is in sheet form rather than roll form, an oven or the like can be provided as the heating mechanism for the media M. The heating conditions for the media M are not limited, but for example, it is conceivable to maintain a heating temperature of about 130°C (e.g., about 120 to 150°C) for about 5 minutes (e.g., about 1 to 10 minutes).

[0036] The media M that has passed through the heating section 44 is wound into a roll on the shaft 48 of the winding section 47. The user cuts out the area containing the image to be transferred to the workpiece WK from the media M wound on the shaft 48 and superimposes it onto the workpiece WK. At this time, as shown in Figure 2(c), the side of the media M with the ink layer IL and adhesive layer AL formed on it (the printed side of the image) is placed facing the surface of the workpiece WK. The adhesive layer AL formed on the surface of the ink layer IL comes into contact with the surface of the workpiece WK. The user then presses the workpiece WK with the media M superimposed on it using the hot press machine 8.

[0037] As shown in Figure 1, the hot press machine 8 comprises a mounting section 81 on which the workpiece WK is placed, and a pressing section 82 positioned above the mounting section 81 in the Z direction, which presses the workpiece WK between itself and the mounting section 81. A heater 83 is built into the mounting section 81. The user places the workpiece WK, which consists of stacked media M, on the mounting section 81 and drives the heater 83 to heat the media M. The user pushes down the pressing section 82, pressing the workpiece WK between the pressing section 82 and the mounting section 81. As shown in Figure 2(c), the ink layer IL with the adhesive layer AL formed on it is pressed onto the surface of the workpiece WK and adheres to the workpiece WK.

[0038] After the pressing process is complete, the user removes the workpiece WK from the hot press machine 8 and peels the media M from the workpiece WK and the ink layer IL adhered to the workpiece WK. As shown in Figure 2(d), in the transferred workpiece WK, the color ink layer COL is superimposed on the white ink layer WHL. This makes the image printed with color ink visible.

[0039] Furthermore, in order to further fix the image transferred to the workpiece WK, pressing may be performed again after peeling off the media M. In this case, paper or the like may be placed between the workpiece WK placed on the mounting section 81 of the hot press machine 8 and the pressing section 82 before pressing. This reduces the likelihood of the image peeling off the workpiece WK during pressing.

[0040] The control device 3 controls the operation of the printer 2. The control device 3 also acts as a print data creation device, creating print data for printing images on the printer 2. Figure 3 is a diagram showing the hardware configuration of the control device 3. As shown in Figure 3, the control device 3 can be composed of a general-purpose information processing device 9 (computer). The information processing device 9 can be, for example, a personal computer, a mobile terminal such as a smartphone, a tablet terminal, etc. Figure 3 is a block diagram showing an example of the hardware configuration of the information processing device 9. As shown in Figure 3, the information processing device 9 has a CPU (Central Processing Unit) 901, ROM (Read Only Memory) 902, RAM (Random Access Memory) 903, HDD (Hard Disk Drive) 904, display 905, input device 906, communication I / F 907 and media I / F 908, etc. Each component is interconnected by a bus.

[0041] The CPU 901 controls the entire information processing device 9. The CPU 901 can load the OS and various programs stored in the ROM 902 or HDD 904 into the RAM 903 and execute them. Alternatively, the CPU 901 can load programs stored in the storage medium RM into the RAM 903 via the media I / F 908 and execute them. The storage medium RM can be an optical storage medium, a magneto-optical storage medium, a magnetic storage medium, a conductive memory tape medium, a semiconductor memory, etc. The information processing device 9 may also include a GPU (Graphics Processing Unit) or the like as a processor along with the CPU 901. The CPU 901 processes information in response to user operations via the input device 906 and displays the processing results on the display 905. The input device 906 can be, for example, a keyboard, mouse, touchpad, touch panel, physical switch, etc.

[0042] The HDD 904 stores programs executed by the CPU 901, data used by the programs, and the like. Note that instead of or in addition to the HDD 904, an SSD (Solid State Drive) may be provided. The communication I / F 907 outputs data received from other devices (such as the printer 2 and other information processing devices) to the CPU 901 via a network NW such as the Internet or a LAN (Local Area Network). Further, the communication I / F 907 transmits data generated by the CPU 901 to other devices. The CPU 901 may load a necessary program onto the RAM 903 from other devices via the network NW. By the CPU 901 executing the application program loaded onto the RAM 903, the functional configuration as the control device 3 is realized.

[0043] FIG. 4 is a diagram showing the functional configuration of the control device 3. As shown in FIG. 4, the control device 3 includes a print control unit 30 that controls the operation of the printer 2, and a print data creation unit 31 that creates print data PD for printing an image on the printer 2. The print control unit 30 controls the operation of each part of the printer 2 based on the print data PD created by the print data creation unit 31. The print data creation unit 31 includes an image data import unit 32, a print condition setting unit 33, a white plate creation unit 34 (area adjustment unit), and an image processing unit 38 (dot data creation unit).

[0044] The image data import unit 32 imports image data ID in which an image to be printed on the medium M is recorded in response to a user's operation input. The user may, for example, import the image data ID created by an external information processing device into the control device 3. Alternatively, when software for creating image data is installed in the control device 3, the control device 3 may create the image data ID.

[0045] The print condition setting unit 33 can set various print conditions when printing an image onto media M in response to user input. Print conditions can include, for example, the type and size of media M used for printing, the type of ink used, print quality, print speed, and overprinting. Overprinting means printing ink such as white ink (W) or clear ink (CL) on top of or below an image printed with color ink. The print condition setting unit 33 can, for example, set the type of ink used for overprinting and the direction in which the ink is overlaid on the image (top or bottom). In this embodiment, the method of printing white ink on top of the image will be mainly described.

[0046] Figure 5 illustrates the effect of overprinting with white ink. Figure 5(a) shows the state in which an image without white ink overprinting has been transferred to a white workpiece WK. Figure 5(b) shows the state in which an image without white ink overprinting has been transferred to a dark-colored workpiece WK. Figure 5(c) shows the state in which an image with white ink overprinting has been transferred to a dark-colored workpiece WK. Note that the adhesive layer AL (see Figure 2) is not shown in Figure 5. Also, hatching is applied to the white workpiece WK and cross-hatching is applied to the dark-colored workpiece WK to distinguish them.

[0047] As shown in Figure 5(a), a color ink layer COL that constitutes the image is formed on the surface of the workpiece WK after transfer. In the case of a white workpiece WK, light L irradiated onto the color ink layer COL is reflected by the surface of the workpiece WK, passes through the color ink layer COL, and enters the user's eye. This allows the user to see the colors of the image. On the other hand, as shown in Figure 5(b), in the case of a dark-colored workpiece WK, light L irradiated onto the color ink layer COL is absorbed by the surface of the workpiece WK and is less likely to be reflected. As a result, the amount of light L entering the user's eye is reduced, making it difficult to see the colors of the image.

[0048] As shown in (c) of FIG. 5, when overprinting with white ink is performed, a white ink layer WHL is formed between the surface of the dark-colored workpiece WK and the color ink layer COL. In this case, the light L irradiated to the color ink layer COL is reflected by the white ink layer WHL, passes through the color ink layer COL, and enters the user's eyes. As a result, the color of the image becomes easier to visually recognize. Thus, when overprinting is performed, the white ink layer WHL functions as a reflective layer, so that even when an image is transferred onto the dark-colored workpiece WK, the visibility of the color of the image can be enhanced.

[0049] The white plate creation unit 34 shown in FIG. 4 creates white plate image data WD based on the image data ID when overprinting with white ink is set as a printing condition. Details of the white plate image data WD and the processing of the white plate creation unit 34 will be described later.

[0050] The image processing unit 38 performs processing for creating print data PD based on the image data ID. The print data PD includes dot data created for each color of ink used for printing an image in the printer 2. For example, the image processing unit 38 performs color conversion processing, halftone processing, rasterization processing, etc. on the image data ID to create dot data. The dot data indicates the ejection position of the ink on the medium M. For example, the dot data is created as a binary tiff format file, and indicates, in binary, whether there is (ejection) or not an ink dot at each coordinate point of the medium M.

[0051] As shown in FIG. 4, the image processing unit 38 creates dot data indicating the ejection position of each of CMYK, which are color inks, based on the image data ID imported by the image data import unit 32. When performing overprinting with white ink, the image processing unit 38 creates, in addition to the CMYK dot data, dot data indicating the ejection position of white ink (W) based on the white plate image data WD created by the white plate creation unit 34.

[0052] The image processing unit 38 adds necessary data such as commands according to the specifications of the printer 2, a thumbnail file, and a job information definition file to the created dot data to create the final print data PD, and outputs it to the print control unit 30.

[0053] The print control unit 30 refers to the dot data for each ink, moves the head 22 of the printer 2 to the coordinate point on the media M where the presence of ink dots is specified, and ejects ink from the corresponding nozzle 23. The print data PD also sets the ejection amount per drop of each ink used for printing. The more ink ejected from the nozzle 23, the larger the ink dot size that lands on the media M. The dot size is controlled, for example, according to the ink ejection amount, to L dot (ejection amount of 18 pL to 22 pL per dot), M dot (ejection amount of about 70 to 80% of L dot), S dot (ejection amount of about 40 to 50% of L dot), etc.

[0054] The following describes the processing details of the white plate creation unit 34. As described above, the white plate creation unit 34 creates white plate image data WD, which is used in the image processing unit 38 to create dot data for white ink. The white plate image data WD indicates the printing area for white ink. In this embodiment, when creating the white plate image data WD, the white plate creation unit 34 performs adjustment processing to reduce white ink bleeding.

[0055] Figure 6(a) shows a white version image data WD created from the image data ID without pixel adjustment processing. Figure 6(b) shows a white version image data WD created from the image data ID after pixel adjustment processing. In Figure 6, as an example of an image, a figure is shown in which the center of a circle (hatched area in the figure) printed with color ink is outlined in white in the shape of a star.

[0056] In the image data ID in Figure 6(a), the circular area excluding the star shape is the area that will be printed with color ink (hereinafter referred to as the "color printing area CPA"). The area around the circle and the star-shaped area in the center of the circle are non-printing areas NPA1 and NPA2, where color ink will not be printed.

[0057] Specifically, the image data ID is a collection of pixels P, and the color print area CPA and the non-print areas NPA1 and NPA2 are each composed of consecutive pixels P. In the image data ID, color information is specified for each pixel P. The pixels P that make up the color print area CPA are specified with color information (RGB values) corresponding to the color to be printed (see the dashed-dotted box in the figure). The pixels P that make up the color print area CPA are specified as "with dots" for color ink in the dot data described above (see Figure 4). On the other hand, the pixels P that make up the non-print areas NPA1 and NPA2 are specified as "without dots" for color ink in the dot data.

[0058] When performing overprinting with white ink, for example, one might consider printing white ink over the entire surface of a pixel P that is printed with color ink. In this case, as shown in Figure 6(a), the color printing area CPA of the image data ID is used as the area to be printed with white ink (hereinafter referred to as the "white printing area WPA") to create the white version image data WD. However, if the color printing area CPA is used directly as the white printing area WPA, there is a possibility that the white ink will easily bleed around the outline of the image printed with color ink.

[0059] As mentioned above, the white ink layer WHL (see Figure 5(c)) formed by overprinting functions as a reflective layer. To increase light reflectivity, in overprinting, the white ink dot size is usually L dot, and the duty cycle (printing rate) is set to 100%, meaning that printing is performed by ejecting across the entire area of ​​the ejection position. In this case, as shown within the dashed-dot frame in Figure 6(a), the white ink dot D may become larger than the pixel P. Furthermore, when the white ink lands on the media M, the dot D becomes even larger due to wetting and spreading. This can cause the white ink to spill out beyond the outline of the image printed with color ink. Also, if there is a non-printing area NPA2 within the color printing area CPA, the white ink may spill inward beyond the non-printing area NPA2. When an image with spilled white ink is transferred to a dark-colored workpiece WK, the spill becomes more noticeable and can affect the quality of the printed material.

[0060] To reduce such white ink bleeding, the white plate creation unit 34 performs pixel adjustment processing on the white printing area WPA when creating the white plate image data WD. As shown in Figure 4, the white plate creation unit 34 has an area determination unit 35, an outline extraction unit 36, and a pixel adjustment unit 37. The area determination unit 35 determines, based on the image data ID, a color printing area CPA and a non-printing area NPA within the color printing area CPA. The outline extraction unit 36 ​​extracts the pixels P that constitute the outline of the color printing area CPA. The outline extraction unit 36 ​​also extracts the pixels P surrounding the non-printing area NPA within the color printing area CPA if there is a non-printing area NPA within the color printing area CPA. The pixel adjustment unit 37 adjusts the pixels P that constitute the white printing area WPA based on the pixels P extracted by the outline extraction unit 36 ​​(the pixels P that constitute the outline of the color printing area CPA and the pixels P that surround the non-printing area NPA). The pixel adjustment unit 37 creates white image data WD based on the adjusted white print area WPA.

[0061] Specifically, as shown in Figure 6(b), the pixel adjustment unit 37 determines the white printing area WPA as the area obtained by excluding the pixels P extracted by the contour extraction unit 36 ​​(pixels P that constitute the contour of the color printing area CPA and pixels P that surround the non-printing area NPA2) from the color printing area CPA. The white printing area WPA after pixel adjustment processing is a reduced version of the color printing area CPA of the image data ID. In addition, the non-printing areas NPA1 and NPA2 are expanded versions of the non-printing areas NPA1 and NPA2 of the image data ID.

[0062] During the pixel adjustment process, for pixels P excluded from the white printing area (WPA), color ink is ejected, but white ink is not. In other words, white ink is not ejected to pixels in the outer contours of images or the contours of white areas, where white ink bleeding is likely to occur. This reduces white ink bleeding.

[0063] A more specific example of the pixel adjustment process will be explained. Figure 7(a) is a diagram illustrating the processing of the region determination unit 35, and Figure 7(b) is a diagram illustrating the processing of the contour extraction unit 36 ​​and the pixel adjustment unit 37. In Figure 7, the letter "P" is shown as an example of an image, and a part of the image data, pixel P, is shown enlarged. Note that the X and Y directions in the figure correspond to coordinates in the data and are different from the X and Y directions shown in Figure 1.

[0064] As shown in Figure 7(a), the region determination unit 35 determines the color printable area CPA and the non-printable areas NPA1 and NPA2 in the image data ID. Known image processing methods can be used for the processing of the region determination unit 35. For example, the region determination unit 35 can determine that a region in which one or more pixels P with color information other than white are continuous in the X direction, Y direction, or diagonal direction is the color printable area CPA. The region determination unit 35 can also determine that a region in which one or more pixels P with color information of white are continuous in the X direction, Y direction, or diagonal direction is the non-printable areas NPA1 and NPA2.

[0065] In the example shown in Figure 7(a), the region determination unit 35 determines that the region consisting of pixels P marked with ● is the color printing region CPA. The region determination unit 35 also determines that the regions consisting of pixels P marked with × are the non-printing regions NPA1 and NPA2. Non-printing region NPA1 is a non-printing region outside the color printing region CPA, and non-printing region NPA2 is a non-printing region inside the color printing region CPA.

[0066] The contour extraction unit 36 ​​can extract pixels P that constitute the contour in the color printing area CPA determined by the area determination unit 35, for example, using an image processing method such as a known edge detection method. In the example of Figure 7(b), the contour extraction unit 36 ​​extracts the pixels P marked with a triangle as pixels P that constitute the contour of the color printing area CPA. The "pixels P that constitute the contour of the color printing area CPA" include at least the outermost pixel P of the color printing area CPA. The "pixels that constitute the contour of the color printing area CPA" may also include a predetermined number of pixels P arranged in the X, Y, or diagonal direction relative to the outermost pixel P. The "predetermined number" is not limited to a specific number and can be set as appropriate. Furthermore, the "predetermined number" may be set to the same number in the X, Y, and diagonal directions, or different numbers may be set. The contour extraction unit 36 ​​may also change the "predetermined number" as appropriate according to the size of the color printing area CPA and perform processing.

[0067] If there is a non-printing area NPA2 within the color printing area CPA, the contour extraction unit 36 ​​can extract pixels P surrounding the non-printing area NPA in the color printing area CPA using known image processing methods such as edge detection. In the example of Figure 7(b), the contour extraction unit 36 ​​extracts the pixels P marked with a square as pixels P surrounding the non-printing area NPA2 within the color printing area CPA. The "pixels P surrounding the non-printing area NPA2" can be a predetermined number of pixels P arranged in the X, Y, or diagonal direction with respect to at least the outermost pixel P of the non-printing area NPA2. The "predetermined number" is not limited to a specific number and can be set as appropriate. The "predetermined number" may be the same in the X, Y, and diagonal directions, or it may be a different number in each direction.

[0068] The pixel adjustment unit 37 can, for example, remove pixels P extracted by the contour extraction unit 36 ​​from the color printing area CPA (pixels P that constitute the contour of the color printing area CPA and pixels P surrounding the non-printing area NPA2), and make the remaining area the white printing area WPA. In the example of Figure 7(b), the area consisting of pixels marked with ● after removing the pixels P marked with △ and □ from the color printing area CPA becomes the white printing area WPA. The pixels P marked with △ and □ are incorporated into the non-printing areas NPA1 and NPA2.

[0069] The pixel adjustment unit 37 changes the color information of pixels P that constitute the white printing area WPA to a single color such as black. At this time, the pixel adjustment unit 37 changes the color information of pixels P that have been excluded from the white printing area WPA (pixels P marked with △ and □) to white (R: 255, G: 255, B: 255). This creates the white plate image data WD. The image processing unit 38 (see Figure 4) can create white ink dot data by performing a color replacement process to replace the color information of the white plate image data WD with white, and then performing the aforementioned color conversion process.

[0070] Figure 8 is a flowchart showing the processing flow of the print data creation unit 31 when white ink overprinting is set as a printing condition. As shown in Figure 8, the area determination unit 35 of the white plate creation unit 34 acquires the image data ID imported into the control device 3 (step S01). Based on the image data ID, the area determination unit 35 determines the color printing area CPA and the non-printing areas NPA1 and NPA2 (step S02: area determination process). The contour extraction unit 36 ​​extracts the pixels P that constitute the contour of the color printing area CPA, and if there is a non-printing area NPA2 within the color printing area CPA, it extracts the pixels P that surround the non-printing area NPA2 in the color printing area CPA (step S03: pixel extraction process). The pixel adjustment unit 37 adjusts the white printing area WPA based on the pixels P extracted by the contour extraction unit 36 ​​(pixels P that constitute the contour of the color printing area CPA and pixels P that surround the non-printing area NPA2) (step S04: pixel adjustment process). Steps S02 to S04 correspond to adjustment processes that adjust the white print area WPA (white ink print area) based on the image data. The pixel adjustment unit 37 creates white plate image data WD based on the adjusted white print area WPA (step S05: white plate creation process).

[0071] The image processing unit 38 creates dot data for color ink and dot data for white ink based on the image data ID and white plate image data WD (Step S06: Dot data creation process). The image processing unit 38 adds necessary data such as commands according to the specifications of the printer 2, thumbnail files, and job information definition files to the created dot data to create the final print data PD and outputs it to the print control unit 30 (Step S07). The print control unit 30 controls the printer 2 based on the input print data PD and performs overprinting.

[0072] As described above, the control device 3 (print data creation device) described in the embodiment has, for example, the following configuration: (1) The control device 3 creates print data PD. Print data PD is data for printing an image onto media M with the printer 2 (printing device). The control device 3 includes an image processing unit 38 (dot data creation unit) and a white plate creation unit 34 (area adjustment unit). The image processing unit 38 creates dot data included in the print data PD (step S06: dot data creation process). The dot data indicates the ink ejection position on media M for each ink color used by the printer 2. When performing overprinting, which involves printing white ink on top of an image printed with color ink, the white plate creation unit 34 adjusts the white printing area WPA, which is the printing area for white ink, based on the image data ID. The white plate creation unit 34 includes an area determination unit 35, an outline extraction unit 36, and a pixel adjustment unit 37. The area determination unit 35 determines the color printing area CPA, which is the printing area of ​​the color ink indicated by the image data ID (Step S02: Area determination process). The contour extraction unit 36 ​​extracts the pixels P that constitute the contour of the color printing area CPA (Step S03: Pixel extraction process). The pixel adjustment unit 37 adjusts the color printing area CPA based on the pixels P that constitute the contour to determine the white printing area WPA (Step S04: Pixel adjustment process). The image processing unit 38 creates dot data for white ink in addition to the dot data for color ink based on the image data ID and the white printing area WPA (Step S06: Dot data creation process). For example, the pixel adjustment unit 37 creates white image data WD that shows the determined white printing area WPA. The image processing unit 38 can perform color conversion processing on the white image data WD to create dot data for white ink.

[0073] Furthermore, the transfer system 1 described in the embodiment comprises, for example, the following configuration: (11) The transfer system 1 comprises the control device 3 described above, a printer 2 (printing device), a shaker 4 (adhesive application device), and a hot press machine 8 (pressing device). The printer 2 prints an image on the media M with color ink based on the print data PD created by the control device, and then prints white ink over the image. The shaker 4 applies hot melt powder HP (adhesive) to the white ink printed on the media M. In the shaker 4, the media M is heated to melt the hot melt powder HP applied to the image, thereby forming an adhesive layer AL on the image. The printed surface of the media M is placed on the workpiece WK, and the image with the adhesive layer AL formed on it can be transferred to the workpiece WK by heating and pressing with the hot press machine 8.

[0074] In DTF, one of the transfer methods, an image printed on media M is coated with hot melt powder HP and melted. Then, media M is placed on workpiece WK and heat-pressed to transfer the image to workpiece WK. The image can be printed with color ink, but if the workpiece WK to be transferred is dark in color, the light L irradiated onto the image may be absorbed by the workpiece WK, affecting the visibility of the image's colors. By performing overprinting with printer 2, a white ink layer WHL is formed beneath the color ink layer COL that constitutes the image. The white ink layer WHL reflects light L, improving the visibility of the image's colors even on dark workpiece WK.

[0075] In overprinting, it is desirable to print the white ink layer (WHL) as a reflective layer using L-dots with a duty cycle (print density) of 100%. However, in this case, the dot size of the white ink may become larger than the pixels (P) that make up the image. This can cause the white ink to bleed out from the outlines and white areas of the image. This bleeding of white ink is particularly noticeable in dark-colored workpieces (WK), and can affect the quality of the printed material.

[0076] In the control device 3 of this embodiment, when performing overprinting with white ink, the white printing area WPA is adjusted based on the image data ID. Specifically, the contour extraction unit 36 ​​of the white plate creation unit 34 extracts pixels P that constitute the contour from the color printing area CPA indicated by the image data ID. The pixel adjustment unit 37 determines the pixels P that constitute the white printing area WPA based on the extracted pixels P. This adjustment process can reduce the amount of white ink that spills out from the contour of the image printed with color ink.

[0077] In this embodiment, the pixel adjustment unit 37 creates white image data WD indicating the determined white printing area WPA, and the image processing unit 38 performs color conversion processing on the white image data WD to create white ink dot data. However, the embodiment is not limited to this. For example, instead of creating white image data, the pixel adjustment unit 37 may output information to the image processing unit 38 about pixels P to be excluded in the white printing area WPA (pixels P that constitute the outline of the color printing area CPA and pixels P that surround the non-printing area NPA2). The image processing unit 38 may create white ink dot data based on the image data ID and the information about the pixels P to be excluded. For example, the image processing unit 38 can create white ink dot data by excluding the pixels P to be excluded from the pixels designated as "with dots" in the color ink (CMYK) dot data created from the image data ID.

[0078] Furthermore, although this embodiment describes an example of application to a transfer system 1 that performs DTF, the invention is not limited to this example. The image printed on the media may be used as a printed material without being transferred to the workpiece WK. For example, if the media M on which the image is printed is dark in color, white ink may be printed on top of the image printed with color ink to form a reflective layer. In this case as well, the adjustment process of this embodiment can reduce the amount of white ink that spills out from the image.

[0079] (2) The pixel adjustment unit 37 can, for example, make the area obtained by excluding the pixels P that constitute the contour from the color printing area CPA into a white printing area WPA.

[0080] By making these adjustments, the white ink will not be overprinted on the outer edges of the image where white ink bleeding is most likely to occur. This reduces white ink bleeding.

[0081] (3) If there is a non-printing area NPA2 within the color printing area CPA where no color ink is printed, the contour extraction unit 36 ​​extracts pixels P surrounding the non-printing area NPA2 in the color printing area CPA. The pixel adjustment unit 37 can make the area obtained by excluding the pixels P that constitute the contour and the pixels P surrounding the non-printing area NPA2 from the color printing area CPA into a white printing area WPA.

[0082] Similar to the outlines of an image, white areas are prone to white ink bleeding. By excluding pixels P surrounding the non-printable area NPA2 from the white printable area WPA, white ink bleeding in the white areas can be reduced.

[0083] (8) The white ink may be an ink having a light-reflective pigment. This allows the white ink layer WHL to function as a light-reflecting layer on the workpiece WK to which the image has been transferred, thereby improving the visibility of the image's colors even on a dark-colored workpiece WK.

[0084] (9, 10) The transparent ink may be an ink that does not contain pigment or dye. This makes it less noticeable if the transparent ink extends beyond the image.

[0085] (i) The contour extraction unit 36 ​​can extract at least the outermost pixel P of the color printing area CPA as the pixels P that constitute the contour. The contour extraction unit 36 ​​can also extract a predetermined number of pixels P that are aligned with the outermost pixel P as the pixels P that constitute the contour. For example, the contour extraction unit 36 ​​can extract a predetermined number of pixels P that are aligned in the X direction, Y direction, or diagonal direction with respect to the outermost pixel P.

[0086] By excluding not only the outermost pixel P from the white printing area WPA, but also a predetermined number of pixels P adjacent to the outermost pixel P, white ink bleeding can be appropriately reduced. The "determined number" is not limited to a specific number and can be set as appropriate. Furthermore, the "determined number" may be the same number in the X, Y, and diagonal directions, or different numbers may be set. The "determined number" may also be changed according to the size of the color printing area CPA. For example, if the image is thin line characters, a large number of pixels P excluded from the white printing area WPA may result in insufficient formation of the reflective white ink layer WHL. In such cases, the contour extraction unit 36 ​​can change the "determined number," which is the number of pixels P extracted, to form the white ink layer WHL within an appropriate range. The user may also specify the "determined number" as a printing condition.

[0087] (ii) The contour extraction unit 36 ​​can extract a predetermined number of pixels P that surround the non-printing area NPA2, specifically those arranged around the outermost pixel P of the non-printing area NPA2. For example, the contour extraction unit 36 ​​can extract a predetermined number of pixels P that are arranged in the X direction, Y direction, or diagonal direction around the outermost pixel P of the non-printing area NPA2.

[0088] If only pixels P adjacent to the outermost pixel P of the non-printing area NPA2 are excluded from the color printing area CPA, white ink bleeding may not be adequately reduced. In such cases, white ink bleeding can be adequately reduced by excluding a predetermined number of pixels P aligned with the outermost pixel P of the non-printing area NPA2 from the white printing area WPA. Note that the "determined number" is not limited to a specific number and can be set as appropriate. Furthermore, the "determined number" may be set to the same number in the X direction, Y direction, and diagonal direction, or different numbers may be set. Also, the "determined number" may be changed according to the size of the color printing area CPA. For example, if the image is thin line characters, if a large number of pixels P are excluded from the white printing area WPA, the reflective white ink layer WHL may not be sufficiently formed. In such cases, the contour extraction unit 36 ​​can change the "determined number," which is the number of pixels P extracted, to form the white ink layer WHL within an appropriate range. Note that the user may specify the "determined number" as a printing condition.

[0089] The effects described above can also be applied to the transfer system 1 to which the control device 3 (print data creation device) is applied, the print data creation method executed by the control device 3, and the program that operates the computer as the control device 3.

[0090] <Modification 1> In the following modifications, variations in the processing of the white plate creation unit 34 will be described. The configuration of the control device 3 in each modification is the same as in the embodiment (see Figure 4).

[0091] Figure 9(a) shows the processing modes of the contour extraction unit 36 ​​and the pixel adjustment unit 37 according to Modification 1. In Modification 1, the region determination unit 35 determines the color print area CPA and the non-print areas NPA1 and NPA2 in the image data ID, similar to the embodiment (see Figure 7(a)).

[0092] As shown in Figure 9(a), the contour extraction unit 36, similar to the embodiment, extracts pixels P that constitute the contour (pixels P marked with △ in the figure) and pixels P that surround the non-printing area NPA2 (pixels P marked with □ in the figure) in the color printing area CPA determined by the area determination unit 35. In the modified example 1, the pixel adjustment unit 37 sets the remaining area after excluding the pixels P extracted by the contour extraction unit 36 ​​(pixels P that constitute the contour of the color printing area CPA and pixels P that surround the non-printing area NPA2) from the color printing area CPA (see Figure 7(a)) as the first white ink printing area FPA. In the example of Figure 9(a), the pixels P marked with ● constitute the first printing area FPA. The first printing area FPA corresponds to the white printing area WPA in the embodiment (see Figure 7(b)).

[0093] The pixel adjustment unit 37 further sets the area composed of pixels P extracted by the contour extraction unit 36 ​​(pixels P that constitute the contour of the color printing area CPA and pixels P that surround the non-printing area NPA2) as the second printing area SPA for white ink. In the example of Figure 9(a), the pixels P marked with a triangle and the pixels P marked with a square constitute the second printing area SPA. The printing density of the white ink in the second printing area SPA is set lower than that of the first printing area FPA. That is, in the embodiment, pixels P that are excluded from the white printing area WPA are set as pixels that print white ink with a small ejection amount in the modified example 1.

[0094] Figure 9(b) shows an example of setting the density and dot size of white ink in the first printing area FPA and the second printing area SPA. As shown in Figure 9(b), the pixel adjustment unit 37 can, for example, set the ejection amount of white ink for pixels P constituting the first printing area FPA to be L dots. The pixel adjustment unit 37 sets the ejection amount for the second printing area SPA to be less than that for the first printing area FPA. The pixel adjustment unit 37 may set all pixels P in the second printing area SPA to the same ejection amount, or it may set the ejection amount differently depending on the position of the pixels P. In the illustrated example, the pixel adjustment unit 37 sets the ejection amount to be lower for pixels P adjacent to non-printing areas NPA1 and NPA2 in the second printing area SPA. Specifically, the pixel adjustment unit 37 sets the ejection amount for pixels P in the second printing area SPA that are not directly in contact with non-printing areas NPA1 and NPA2 to be M dots. The pixel adjustment unit 37 sets the ejection amount for pixels P adjacent to non-printing areas NPA1 and NPA2 within the second printing area SPA to become S dots.

[0095] In Modification 1, although there are differences in the amount of ink ejected, white ink is printed over the entire surface of the color inks that make up the image. This makes it possible to make the thickness of the printed material more uniform. Also, for example, when an image is composed of small shapes or thin lines of text, the outlines and white areas may occupy a relatively large area within the overall image. In such cases, if no white ink is printed on the outlines and white areas, it may not be possible to secure a sufficient area for the white ink layer WHL, which acts as a reflective layer. In Modification 1, since the outlines and white areas also have a reflective layer formed as the second printing area SPA, visibility can be improved even in images of small shapes or thin lines of text. As mentioned above, white ink bleeding is likely to occur when the dot size of the white ink is larger than the pixel P. Therefore, by setting the amount of ink ejected in the second printing area SPA so that the dot size is smaller than that of the first printing area FPA, white ink bleeding can be reduced, similar to the embodiment. Furthermore, within the second printing area SPA, by setting a lower white ink ejection amount in pixels P adjacent to the non-printing areas NPA1 and NPA2, where bleeding is more likely to occur, it becomes easier to achieve both image visibility and reduced bleeding.

[0096] As described above, the control device 3 of the modified example 1 has, for example, the following configuration: (4) The pixel adjustment unit 37 can make the area obtained by excluding the pixels P extracted by the contour extraction unit 36 ​​from the color printing area CPA (pixels P that constitute the contour of the color printing area CPA and pixels P that surround the non-printing area NPA2) into the first printing area FPA for white ink. The pixel adjustment unit 37 can make the area composed of the pixels P extracted by the contour extraction unit 36 ​​(pixels P that constitute the contour of the color printing area CPA and pixels P that surround the non-printing area NPA2) into the second printing area SPA for white ink, which is printed with a smaller ejection amount than the first printing area FPA.

[0097] This configuration allows a reflective layer to be formed across the entire surface of the color inks that make up the image, thereby improving the visibility of the image. In addition, in areas where image bleeding is likely to occur, such as contours and white areas, the dot size of the white ink is reduced as a second printing area (SPA), thus reducing bleeding. For example, if an image consists of small shapes or thin lines of text, if no white ink is printed on the contours of the image, the formation of the reflective layer may be insufficient. Therefore, for such images, it is preferable to create the print data PD using the method of Modified Example 1. Furthermore, since white ink is printed over the entire surface of the color inks that make up the image, the thickness of the printed material can be made more uniform.

[0098] (iii) The pixel adjustment unit 37 can set pixels P adjacent to non-printing areas NPA1 and NPA2 in the second printing area SPA to be printed with a smaller ejection amount than other pixels P.

[0099] Within the second printing area (SPA), by further reducing the amount of white ink ejected at pixels P adjacent to the non-printing areas NPA1 and NPA2, where overprinting is more likely to occur, it becomes easier to achieve both image visibility and reduced overprinting.

[0100] <Modification 2> Figure 10 is a diagram showing the processing method of the pixel adjustment unit 37 according to Modification 2. As shown in Figure 10, in Modification 2, the pixel adjustment unit 37, similar to the embodiment, sets the remaining area after excluding the pixels P extracted by the contour extraction unit 36 ​​(pixels P that constitute the contour of the color printing area CPA and pixels P surrounding the non-printing area NPA2) from the color printing area CPA to the white printing area WPA. The pixel adjustment unit 37 then sets the area composed of the pixels P extracted by the contour extraction unit 36 ​​in the color printing area CPA (pixels P that constitute the contour of the color printing area CPA and pixels P surrounding the non-printing area NPA2) to be printed with clear ink (transparent ink) to the clear printing area CLA. For example, the pixel adjustment unit 37 may set the discharge amount of clear ink to be L dot for all pixels P that constitute the clear printing area CLA. Alternatively, similar to Modification 1, the discharge amount may be set differently depending on the position of the pixels P. For example, the pixel adjustment unit 37 may set a lower ink ejection amount for pixels P adjacent to non-printing areas NPA1 and NPA2 within the clear printing area CLA. The pixel adjustment unit 37 creates white image data WD based on the set white printing area WPA and creates clear image data CD based on the set clear printing area CLA. In the modified example 2, the image processing unit 38 (see Figure 4) processes using the image data ID and white image data WD, as well as the clear image data CD. As a result, the print data PD created in the modified example 2 includes dot data for the color inks CMYK, dot data for the white ink (W), and dot data for the clear ink (CL), as shown in Figure 10.

[0101] In variation 2, clear ink is applied instead of white ink to the outlines and white areas of the image. When transferring the image to a dark-colored workpiece (WK), any excess clear ink is less noticeable. Furthermore, because white ink or clear ink is applied over the entire surface of the color inks that make up the image, the thickness of the printed material can be made more uniform, thus contributing to improved print quality.

[0102] As described above, the control device 3 of the modified example 2 has the following configuration, for example: (5) The pixel adjustment unit 37 creates white image data WD as the white printing area WPA (white ink printing area) by excluding the pixels P extracted by the contour extraction unit 36 ​​from the color printing area CPA (pixels P that constitute the contour of the color printing area CPA and pixels P that surround the non-printing area NPA2). The pixel adjustment unit 37 creates clear image data CD as the clear printing area CLA (clear ink printing area) by excluding the area composed of the pixels P extracted by the contour extraction unit 36 ​​(pixels P that constitute the contour of the color printing area CPA and pixels P that surround the non-printing area NPA2).

[0103] This configuration makes it less noticeable if the clear ink spills over the image when transferring it to a dark-colored workpiece (WK). Furthermore, because the white or clear ink is printed over the entire surface of the color inks that make up the image, the thickness of the printed material can be made more uniform, contributing to improved print quality.

[0104] <Modification 3> Figure 11 is a diagram showing the processing method of the pixel adjustment unit 37 according to Modification 3. Modification 3 describes a preferred processing method when the image has a narrow area NP with a narrow width in the X or Y direction. As shown in Figure 11(a), the pixel adjustment unit 37 can set the remaining area after excluding the pixels P extracted by the contour extraction unit 36 ​​(pixels P that constitute the contour of the color printing area CPA and pixels P surrounding the non-printing area NPA2) from the color printing area CPA, similar to the embodiment, to be the white printing area WPA. In Modification 3, the pixel adjustment unit 37 determines whether the set white printing area WPA has a narrow area NP. In Figure 11(a), the narrow area NP is shown with double hatching and enclosed by a thick line. The pixel adjustment unit 37 can determine, for example, that the white printing area WPA has a narrow area NP if there is a part where the number of pixels in the X or Y direction is less than or equal to a predetermined number (for example, 2 pixels). As shown in Figure 11(a), the white print area (WPA) may have a narrow section (NP) in part. Alternatively, if the image consists of small shapes or thin lines of text, the entire white print area (WPA) may be a narrow section (NP).

[0105] As shown in Figure 11(b), if there is a narrow section NP in the white printing area WPA, the pixel adjustment unit 37 determines which pixels P surround the narrow section NP among the pixels P excluded from the white printing area WPA (pixels P that constitute the outline of the color printing area CPA and pixels P that surround the non-printing area NPA2). The pixel adjustment unit 37 incorporates at least a portion of the pixels P surrounding the narrow section NP (pixels P marked with a circle in the figure) into the narrow section NP. As a result, the white printing area WPA is expanded only to the portion of the narrow section NP.

[0106] The pixel adjustment unit 37 performs this process to create the white image data WD, so that white ink is printed over the contour area of ​​the narrow part NP of the image. If all the pixels P that make up the contour and the pixels P surrounding the non-printable area NPA2 are excluded in the narrow part NP of the image, the white ink layer WHL may not be formed sufficiently. By performing the process of Modification 3, the white ink layer WHL is properly formed in the narrow part NP, and the overall visibility of the image can be improved. In addition, since pixel adjustment is performed in the parts of the image other than the narrow part NP, as in the embodiment, white ink bleeding can be reduced.

[0107] The pixel adjustment unit 37 may also set the narrow area NP to be an area where white ink is printed at a discharge amount less than the discharge amount set for the white printing area WPA (for example, the discharge amount that results in an L dot). In this case, the dot size of the white ink discharged to the narrow area NP becomes smaller, thus reducing white ink bleeding. The pixel adjustment unit 37 may also set the narrow area NP to be an area where clear ink is printed instead of white ink. Clear ink is less noticeable even if it bleeds outside the image. The pixel adjustment unit 37 can make white ink bleeding less noticeable by performing these operations, for example, when the area occupied by the narrow area NP in the image is large, or when the entire image is the narrow area NP. The pixel adjustment unit 37 may also perform these operations, for example, when the area occupied by the narrow area NP in the white printing area WPA exceeds a certain percentage. This allows for appropriate printing of white ink according to the shape of the image.

[0108] As described above, the control device 3 of the modified example 3 has, for example, the following configuration: (6) The pixel adjustment unit 37 can make the area obtained by excluding the pixels P extracted by the contour extraction unit 36 ​​from the color printing area CPA (pixels P that constitute the contour of the color printing area CPA and pixels P surrounding the non-printing area NPA2) into the white printing area WPA (white ink printing area). If there is a narrow section NP in the white printing area WPA, the pixel adjustment unit 37 can incorporate at least a portion of the pixels P surrounding the narrow section NP from the excluded area into the narrow section NP.

[0109] With this configuration, white ink is printed in the narrow areas (NP) of the image without excluding the contours. This ensures that the white ink layer (WHL) is properly formed across the entire image, reducing white ink bleeding and improving image visibility.

[0110] (7) The pixel adjustment unit 37 can make the pixels P constituting the narrow portion NP an area where white ink is printed with an ejection amount less than the ejection amount set for the white printing area WPA, or an area where clear ink is printed.

[0111] By printing white ink in a small amount of ink at the narrow NP (non-printing) area of ​​the image, ink bleeding can be reduced. Alternatively, by printing clear ink at the narrow NP area of ​​the image, ink bleeding can be made less noticeable. This can improve the quality of printed materials.

[0112] (iv) The pixel adjustment unit 37 can determine that a portion of the white printing area WPA where the number of pixels in the X direction (one direction) or the Y direction (the other direction perpendicular to the one direction) is less than or equal to a predetermined number is a narrow portion NP. If the area occupied by the narrow portion NP in the white printing area WPA is greater than or equal to a certain proportion, the pixel adjustment unit 37 can make the pixels P constituting the narrow portion NP an area where white ink is printed with a discharge amount less than the discharge amount set in the white printing area WPA, or an area where clear ink is printed.

[0113] This configuration allows for appropriate printing of white ink according to the shape of the image.

[0114] The present invention is not limited to the embodiments and modifications described above, and can be modified as appropriate within the scope of the technical idea of ​​the present invention. Furthermore, the modifications may not only be applied to the embodiments, but at least a part of the content of each may be applied to other modifications. In addition, the effects described with respect to the transfer method also apply to the transfer system 1 that performs the transfer method and to the method of manufacturing printed materials.

[0115] 1 Transfer system 2 Printer (printing device) 3 Control device (print data creation device) 4 Shaker (adhesive application device) 8 Hot press (pressing device) 34 White plate creation unit 35 Area determination unit 36 ​​Contour extraction unit 37 Pixel adjustment unit 38 Image processing unit (dot data creation unit) PD Print data M Media ID Image data WD White plate image data CD Clear plate image data P Pixel CPA Color printing area (color ink printing area) NPA1, NPA2 Non-printing area WPA White printing area (white ink printing area) FPA First printing area (first white ink printing area) SPA Second printing area (second white ink printing area) CLA Clear printing area (clear ink printing area) NP Narrow area

Claims

1. A print data creation device for creating print data for printing an image on media using a printing device, comprising: a dot data creation unit that creates dot data indicating the ink ejection position on the media for each color of ink used by the printing device, based on image data, as the print data; an area adjustment unit that adjusts the printing area of ​​the white ink based on the image data when performing overprinting, in which white ink is printed on top of the image printed with color ink, wherein the area adjustment unit comprises: an area determination unit that determines the printing area of ​​the color ink shown in the image data; an outline extraction unit that extracts pixels constituting the outline of the printing area of ​​the color ink; and a pixel adjustment unit that determines the printing area of ​​the white ink by adjusting the printing area of ​​the color ink based on the pixels constituting the outline, wherein the dot data creation unit creates dot data for the white ink in addition to the dot data for the color ink based on the image data and the printing area of ​​the white ink.

2. The print data creation apparatus according to claim 1, characterized in that the pixel adjustment unit sets the area obtained by excluding the pixels constituting the contour from the print area of ​​the color ink as the print area of ​​the white ink.

3. The print data creation apparatus according to claim 2, wherein the contour extraction unit extracts pixels surrounding the non-printed area within the color ink printing area if there is a non-printed area within the color ink printing area, and the pixel adjustment unit sets the area obtained by excluding the pixels constituting the contour and the pixels surrounding the non-printed area from the color ink printing area as the white ink printing area.

4. The print data creation apparatus according to claim 2 or claim 3, characterized in that the pixel adjustment unit sets the area obtained by excluding the pixels extracted by the contour extraction unit from the print area of ​​the color ink as the first print area of ​​the white ink, and the area composed of the pixels extracted by the contour extraction unit as the second print area of ​​the white ink, which is printed with a smaller ejection amount than the first print area.

5. The print data creation apparatus according to claim 2 or 3, characterized in that the pixel adjustment unit sets the area obtained by excluding the pixels extracted by the contour extraction unit from the print area of ​​the color ink as the print area of ​​the white ink, and the area composed of the pixels extracted by the contour extraction unit as the print area of ​​the transparent ink.

6. The print data creation apparatus according to claim 2 or 3, wherein the pixel adjustment unit sets the area obtained by excluding the pixels extracted by the contour extraction unit from the print area of ​​the color ink as the print area of ​​the white ink, and if there is a narrow area in the print area of ​​the white ink, the pixel adjustment unit incorporates at least a portion of the pixels surrounding the narrow area from the excluded area into the narrow area.

7. The print data creation apparatus according to claim 6, characterized in that the pixel adjustment unit sets the pixels constituting the narrow portion to an area in which white ink is printed with a discharge amount less than a set discharge amount, or an area in which transparent ink is printed.

8. The print data creation apparatus according to claim 1, characterized in that the white ink is an ink having a light-reflective pigment.

9. The print data creation apparatus according to claim 5, characterized in that the transparent ink is an ink that does not contain a pigment or dye.

10. The print data creation apparatus according to claim 7, characterized in that the transparent ink is an ink that does not contain a pigment or dye.

11. A transfer system comprising a print data creation device according to claim 1, the transfer system comprising: a printing device that prints the image on the medium with the color ink and prints the white ink over the image based on the print data created by the print data creation device; an adhesive application device that applies adhesive to the white ink printed on the medium; and a pressing device that transfers the image to which the adhesive has been applied to the workpiece by pressing the printed surface of the medium onto the workpiece.

12. A method for creating print data for printing an image onto a medium using a printing device, comprising: a dot data creation process that creates dot data indicating the ink ejection position on the medium for each color of ink used by the printing device, based on image data, as the print data; and an adjustment process that adjusts the printing area of ​​the white ink based on the image data when performing overprinting, in which white ink is printed on top of an image printed with color ink, wherein the adjustment process comprises: an area determination process that determines the printing area of ​​the color ink shown in the image data; an outline extraction process that extracts pixels constituting the outline of the printing area of ​​the color ink; and a pixel adjustment process that determines the printing area of ​​the white ink by adjusting the printing area of ​​the color ink based on the pixels constituting the outline, wherein in the dot data creation process, dot data for the white ink is created in addition to the dot data for the color ink based on the image data and the printing area of ​​the white ink.

13. A program for creating print data for printing an image on media using a printing device, the program comprising: causing a computer to perform a dot data creation process that creates dot data indicating the ink ejection position on the media for each color of ink used by the printing device, based on image data, as the print data; and, in the case of overprinting, which involves printing white ink on top of an image printed with color ink, an adjustment process that adjusts the printing area of ​​the white ink based on the image data, wherein the adjustment process includes: an area determination process that determines the printing area of ​​the color ink shown in the image data; an outline extraction process that extracts pixels constituting the outline of the printing area of ​​the color ink; and a pixel adjustment process that determines the printing area of ​​the white ink by adjusting the printing area of ​​the color ink based on the pixels constituting the outline, the program characterized in that, in the dot data creation process, dot data for the white ink is created in addition to the dot data for the color ink based on the image data and the printing area of ​​the white ink.

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