Printing methods

Abstract

This suppresses unevenness in print density caused by the presence or absence of pressure in the ink receiving layer. [Solution] A printing method for ejecting ink droplets from a print head onto a printing medium having an ink-receiving layer on its surface containing dispersed ink receptors, comprising: a pressurizing step of pressurizing the ink-receiving layer with a pressurizing part that contacts the ink-receiving layer; and a recording step of not ejecting the ink droplets from the print head to the parts of the ink-receiving layer that are not pressurized by the pressurizing part, and ejecting the ink droplets from the print head to the parts that are pressurized by the pressurizing part.

Description

Technical Field

[0001] The present invention relates to a printing method for discharging ink droplets onto a printing medium having an ink receiving layer.

Background Art

[0002] [[ID=]12]As a printing device, an inkjet printer that prints an image by discharging ink droplets onto a transfer medium for the DTF (Direct to Film) method is known. The transfer medium includes, for example, a support layer such as a resin film to be peeled off, and an ink receiving layer for holding the landed ink. The ink receiving layer contains, for example, particles of an ink receptor such as silica or alumina in a dispersed state. The inkjet printer includes, for example, a plurality of driven rollers that contact the ink receiving layer of the transfer medium, and a driving roller that moves the transfer medium in the transport direction. The transfer medium moves in the transport direction while being sandwiched between the driven roller and the driving roller.

[0003] Patent Document 1 discloses an inkjet recording medium having two or more ink receiving layers, an upper layer and a lower layer, on a support. The upper layer contains a pigment containing 90% by mass or more of alumina hydrate and polyvinyl alcohol. The lower layer contains a pigment containing 20% by mass or more of silica and polyvinyl alcohol.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Upon examining the image printed on the transfer medium, it was found that the density differed between areas where the driven roller contacted the ink receiving layer and areas where it did not, resulting in uneven shading in the image. Therefore, it is desirable to suppress such uneven shading. [Means for solving the problem]

[0006] The present invention is a printing method for dispensing ink droplets onto a printing medium having an ink-receiving layer on its surface containing dispersed ink receptors, A pressurizing step in which the ink receiving layer is pressurized by a pressurizing section that contacts the ink receiving layer, In the ink receiving layer, the ink droplets are not ejected from the print head to the portion not pressurized by the pressurizing section, and the ink droplets are ejected from the print head to the portion pressurized by the pressurizing section. It has an embodiment that includes this. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram illustrating an example of a printing system configuration. [Figure 2] A schematic diagram illustrating an example of the layered structure of a transfer medium. [Figure 3] Figure 3A is a schematic plan view showing an example of the printer's configuration, and Figure 3B is a schematic side view showing an example of the transport unit's configuration. [Figure 4] A schematic bottom view showing an example of the nozzle surface of a print head. [Figure 5] A block diagram schematically showing an example of the configuration of a printing device. [Figure 6] A schematic diagram illustrating an example of a printing method onto a transfer medium. [Figure 7] Figure 7A is a schematic plan view showing another example of the printer configuration, and Figure 7B is a schematic side view showing another example of the transport unit configuration. [Figure 8] A schematic diagram showing an example of a carriage with a pressurized section. [Figure 9] A flowchart schematically illustrating an example of roller lifting and lowering control processing. [Figure 10]A schematic plan view illustrating a comparative example of printers. [Modes for carrying out the invention]

[0008] The embodiments of the present invention will be described below. Of course, the following embodiments are merely illustrative of the present invention, and not all of the features shown in the embodiments are necessarily essential to the solution of the invention.

[0009] (1) Summary of embodiments included in the present invention: First, an overview of the embodiments included in the present invention will be described with reference to the examples shown in Figures 1 to 10. Note that the figures in this application are schematic examples, and the scale of each part may differ from reality in order to make each part of these figures recognizable. The magnification in each direction shown in these figures may also differ, and the figures may not be consistent. Of course, the elements of this embodiment are not limited to the specific examples indicated by the reference numerals. In "Overview of Embodiments Included in the Present Invention," the text in parentheses indicates supplementary explanation of the preceding word. Furthermore, in this application, the numerical range "Min~Max" means that the minimum value Min is greater than or equal to the maximum value Max. The composition ratio expressed by the chemical formula represents the stoichiometric ratio, and substances expressed by the chemical formula may include those that deviate from the stoichiometric ratio.

[0010] [Aspect 1] As illustrated in Figures 1-3B, etc., a printing method according to one embodiment is a printing method in which ink droplets 37 are ejected from a print head 30 onto a printing medium (e.g., a transfer medium M1) having an ink receiving layer 72 on its surface containing dispersed ink receptors 73, and includes the following steps. (a1) Pressurization step ST1 in which the ink receiving layer 72 is pressurized by a pressurizing part 3 that is in contact with the ink receiving layer 72. (a2) Recording step ST2 wherein, in the ink receiving layer 72, the ink droplets 37 are not ejected from the print head 30 to the portion A3 that is not pressurized by the pressurizing section 3, and the ink droplets 37 are ejected from the print head 30 to the portions that are pressurized by the pressurizing section 3 (for example, portions A1, A2).

[0011] First, the comparative example inkjet printer 902 shown in Figure 10 will be described. The printer 902 includes a carriage 33 on which a print head 30 is provided, a main scanning drive unit 51, a sub-scanning drive unit 52, a transport unit 55 for the transfer medium M1, etc. The transfer medium M1 has an ink-receiving layer 72 on its surface that contains dispersed ink receptors. The main scanning drive unit 51 performs a main scan, moving the carriage 33 in the scanning direction D3. The scanning direction D3 shown in Figure 10 is also the width direction D2 of the transfer medium M1, and is a general term for the forward direction D11 and the return direction D12. The sub-scanning drive unit 52 performs a sub-scan, moving the carriage 33 in the transport direction D1 which is perpendicular to the scanning direction D3. During the main scan, the print head 30 ejects ink droplets, and sub-scanning is performed between main scans, so that an image is printed in the print area A0 on the ink-receiving layer 72. The transport unit 55 is equipped with a transport roller pair 60 that transports the transfer medium M1 toward the carriage 33 along the transport direction D1. The transport roller pair 60 includes a drive roller 61 that contacts the back surface of the transfer medium M1 on the platen 58, and a plurality of driven rollers 62 that contact the front surface of the transfer medium M1. The plurality of driven rollers 62 are spaced apart in the width direction D2 perpendicular to the transport direction D1. The transfer medium M1 nipped by the transport roller pair 60 is transported toward the carriage 33, and ink droplets are ejected from the print head 30 onto the ink receiving layer 72, thereby forming an image IM1 in the print area A0.

[0012] Upon examining the printed image IM1, which was printed to have a uniform density, it was found that the density differed between the area A92 where the driven roller 62 was in contact with the ink receiving layer 72 and the area A91 where the driven roller 62 was not in contact with the ink receiving layer 72. Figure 10 shows that the contact area A92 is lighter than the non-contact area A91. When the driven roller 62 comes into contact with the ink receiving layer 72, the ink receiving layer 72 is pressed by being sandwiched between the drive roller 61 and the driven roller 62. From this, it is thought that the color development of the ink changes in the contact area A92 due to changes in the particle structure, such as the crushing of ink receptor particles contained in the ink receiving layer 72, resulting in unevenness in density in the printed image.

[0013] In the above-described aspect 1, as illustrated in FIG. 3A and the like, in the ink receiving layer 72, ink droplets 37 are not ejected from the print head 30 to the portion A3 that is not pressurized by the pressurizing portion 3, and ink droplets 37 are ejected from the print head 30 to the pressurized portions (A1, A2) by the pressurizing portion 3. Thereby, the image IM1 is printed on the ink receiving layer 72 that is always in a pressurized state. Therefore, the above-described aspect 1 can provide a printing method capable of suppressing unevenness in density of the printing result due to the presence or absence of pressurization of the ink receiving layer.

[0014] Various examples can be considered in the above-described aspects. Examples of the printing medium include a transfer medium in which an ink receiving layer is laminated on a resin film, printing paper in which an ink receiving layer is laminated on paper, and the like. The pressurizing portion may be a roller included in a pair of conveying rollers that convey the printing medium, or may be a roller different from the roller. Of course, the above remarks are also applicable in the following aspects.

[0015] [Aspect 2] The ink receiving layer 72 may contain at least one of silica particles and alumina particles as the ink receptor 73. The particles of silica or alumina change in structure when the ink receiving layer 72 is pressurized by the pressurizing portion 3. Therefore, the above aspect can provide a suitable printing method for suppressing unevenness in density of the printing result due to the presence or absence of pressurization of the ink receiving layer.

[0016] Here, alumina includes hydrated alumina. This remark is also applicable in the following aspects. <�

[0017] [Aspect 3] As illustrated in Figure 3A, etc., in the pressurization step ST1, the printing medium (M1) may be transported in the transport direction D1 by a transport unit 55 that includes a plurality of rollers (e.g., driven rollers 62) as the pressurization unit 3. In the recording step ST2, the ink droplets 37 may be ejected from the print head 30 to the locations (A1, A2) that have been pressurized by the plurality of rollers (62) after they have been transported in the transport direction D1. The plurality of rollers (62) may include a plurality of first rollers 62a arranged at intervals in the width direction D2 intersecting the transport direction D1, and a second roller 62b located in a different position from the plurality of first rollers 62a in the transport direction D1. The second roller 62b may pressurize the portion A1 of the entire range in the ink receiving layer 72 from which the ink droplets 37 are ejected from the print head 30 that is not pressurized by the plurality of first rollers 62a. In the above case, the portion A1 of the entire range in the ink receiving layer 72 where ink droplets 37 are ejected from the print head 30 that is not pressurized by the multiple first rollers 62a is pressurized by the second roller 62b. Therefore, the above embodiment can provide a suitable printing method that suppresses unevenness in the density of the printed result due to the presence or absence of pressurization of the ink receiving layer.

[0018] Here, "first," "second," ... in this application are terms used to identify each component included in a group of similar components, and do not imply any order. This supplementary statement also applies to the following embodiments.

[0019] [Aspect 4] The pressure applied by the second roller 62b to the ink receiving layer 72 may be equal to the pressure applied by the plurality of first rollers 62a to the ink receiving layer 72. In the above case, the ink receiving layer 72 is continuously pressurized with equal pressure in the width direction D2. Therefore, the above embodiment can further suppress unevenness in the density of the printed result due to the presence or absence of pressurization of the ink receiving layer.

[0020] [Aspect 5] As illustrated in Figure 7A, in the pressurization step ST1, the printing medium (M1) may be transported in the transport direction D1 by the transport unit 55 which includes the roller (62) as the pressurization unit 3. In the recording step ST2, the ink droplet 37 may be ejected from the print head 30 to the location (A2) after the location (A2) pressurized by the roller (62) has been transported in the transport direction D1. The roller (62) may be continuous over the entire range (for example, the printing area A0) over which the ink droplet 37 is ejected from the print head 30 to the ink receiving layer 72 in the width direction D2 intersecting the transport direction D1. In the above case, the entire area (A0) in the ink receiving layer 72 over which ink droplets 37 are ejected from the print head 30 is pressurized by the roller (62). Therefore, the above embodiment also provides a suitable printing method that suppresses unevenness in the density of the printed result due to the presence or absence of pressurization of the ink receiving layer.

[0021] [Aspect 6] As illustrated in Figure 8, this printing method may further include the following steps. (a3) Scanning step ST3, which moves the carriage 33 on which the print head 30 and the pressurizing unit 3 are provided in the scanning direction D3. In the ink receiving layer 72, ink droplets 37 may be ejected from the print head 30 provided on the carriage 33 to the location pressurized by the pressurizing section 3 provided on the carriage 33. In the above case, ink droplets 37 are ejected from the print head 30 provided on the carriage 33 to the areas in the ink receiving layer 72 that are pressurized by the pressurizing section 3 provided on the carriage 33. As a result, the image IM1 is printed on the ink receiving layer 72, which is always under pressure. Therefore, the above embodiment also provides a suitable printing method that suppresses unevenness in the density of the printed result due to the presence or absence of pressure in the ink receiving layer.

[0022] Furthermore, the above-described embodiments are applicable to a printing apparatus that implements the above-described printing method, a printing system including the printing apparatus, a method for controlling the above-described pressure unit and print head, a program for controlling the above-described pressure unit and print head, a computer-readable recording medium on which the program is recorded, and so on. In addition, the above-described printing apparatus may be composed of multiple dispersed parts.

[0023] (2) Specific examples of printing systems: Figure 1 schematically illustrates the configuration of a printing system that forms an image IM1 on a transfer medium M1 as a printing medium and transfers the image IM1 to a transfer medium M2. The printing system shown in Figure 1 includes a printing device 1, an adhesive application device 100, and a thermal transfer device 200. Figure 2 schematically illustrates the layer structure of the transfer medium M1. The printing device 1 may be a standalone printer 2, but as shown in Figure 1, it may consist of a printer 2 and a host device HO1. The host device HO1 shown in Figure 1 can generate image data DA1 corresponding to the image IM1 to be transferred, and can transmit the image data DA1 to the printer 2. Hereinafter, the image IM1 to be transferred will also be referred to as the transferred image IM1. The printer 2 is equipped with a printing unit 20 that ejects ink onto the transfer medium M1, and forms the image IM1 corresponding to the image data DA1 on the transfer medium M1. The adhesive application device 100 is equipped with an adhesive tank 110 that adheres adhesive 111 to the ink on the transfer medium M1, and a heating unit 120 that heats the transfer medium M1 after the adhesive has been applied. The thermal transfer device 200 transfers the image IM1 from the transfer medium M1 to the transfer medium M2.

[0024] The transfer medium M1 can be a transfer film or the like that which can transfer an image by the DTF (Direct to Film) method. Referring to Figure 2, the transfer film as the transfer medium M1 includes a support layer 71 such as a resin film, and an ink-receiving layer 72 containing dispersed ink receptors 73. The transfer film is an example of a printing medium having an ink-receiving layer 72 on its surface. The support layer 71 may also be a release layer that is peeled off after the image IM1 has been transferred to the transfer medium M2. The support layer 71 can preferably be made of a resin film such as PET (polyethylene terephthalate) film. Of course, the material of the support layer 71 may also include paper or metal, and the support layer 71 may be a metal film.

[0025] The ink-receiving layer 72 may contain a binder together with the ink receptor 73. Examples of the aforementioned binders include polyvinyl alcohol, starch derivatives, cellulose derivatives, latex, synthetic resin binders, etc. For example, if the ink-receiving layer 72 contains 5 to 20% by weight of polyvinyl alcohol, the ink receptor 73 is well retained, and good ink absorption is obtained in the ink-receiving layer 72. The thickness of the ink-receiving layer 72 can be, for example, 3 to 100 μm.

[0026] The ink acceptor particles 73 are dispersed in the ink acceptor layer 72. The ink acceptor layer 72 may contain at least one of silica particles and alumina particles as the ink acceptor 73. Silica is expressed as SiO2 in stoichiometric ratios and preferably has pores. Examples of silica with pores include colloidal silica and vapor-phase silica. Alumina may be alumina hydrate containing aluminum hydroxide expressed as Al(OH)3 in stoichiometric ratios and preferably has pores. Alumina hydrate with pores can be obtained, for example, by hydrolysis of aluminum alkoxide or sodium aluminate, or by neutralization of an aqueous solution of aluminate. The ink acceptor 73 may also be a combination of silica and alumina. For example, if the ink acceptor layer 72 contains 80-95% by weight of ink acceptor 73, the ink acceptor 73 is well retained and good ink absorption is obtained in the ink acceptor layer 72. The volume-average particle diameter of the ink receptor 73 is preferably less than or equal to the thickness of the ink receptor layer 72.

[0027] Adhesive 111 can be a powdered adhesive such as a powdered hot melt adhesive. Hot melt adhesives are thermoplastic resin powders that melt when heated above their melting point and solidify when cooled. Hot melt adhesives can contain one or more thermoplastic resins selected from polyurethane resin, polyolefin resin, polyamide resin, polyester resin, etc. The transfer medium M2 can be a fabric such as knitted or woven fabric, a nonwoven fabric, or a processed fabric such as a T-shirt.

[0028] As will be explained in more detail later, the printing apparatus 1 performs the pressing process ST1, the recording process ST2, the scanning process ST3, and the base formation process ST4. The adhesive application apparatus 100 performs the adhesive application process ST5 and the heating process ST6. The thermal transfer apparatus 200 performs the transfer process ST7.

[0029] Figure 3A is a schematic plan view illustrating the configuration of the printer 2 according to the first specific example. Figure 3B is a schematic side view illustrating the configuration of the transport unit 55 of the printer 2. Figure 4 is a schematic bottom view illustrating the nozzle surface 30a of the print head 30. Figure 5 is a schematic block diagram illustrating the configuration of the printing device 1. Figure 6 schematically illustrates the printing method on the transfer medium M2. Printer 2 is an inkjet printer that ejects liquid ink droplets 37. Printer 2 includes a control unit 10, a printing unit 20, a semiconductor memory called RAM (Random Access Memory) 21, a communication interface 22, a storage unit 23, an operation panel 24, etc. The control unit 10, RAM 21, communication interface 22, storage unit 23, and operation panel 24 are connected to a bus and are able to input and output information to each other. The printing unit 20 includes a print head 30 and a drive unit 50.

[0030] The control unit 10 includes a processor, a CPU (Central Processing Unit) 11, a color conversion unit 12, a halftone processing unit 13, a rasterization processing unit 14, a drive signal transmission unit 15, and the like. The control unit 10 can be configured using an SoC (System on a Chip) or the like. Based on image data DA1 acquired from a host device HO1, an external memory (not shown), or the like, the control unit 10 controls the print head 30 and the drive unit 50 so that an image IM1 of colored ink 36a and a layer of base ink 36b are formed on the transfer medium M1. The image data DA1 includes, for example, two pixels each containing R (red), G (green), and B (blue). 8 RGB data containing integer values ​​for grayscale can be applied.

[0031] The CPU 11 is the device that primarily handles information processing and control in the printer 2. The color conversion unit 12 has a color conversion LUT (lookup table) that defines the correspondence between the gradation values ​​of R, G, and B and the gradation values ​​of C (cyan), M (magenta), Y (yellow), K (black), and W (white). In the color conversion LUT, the gradation value of W is, for example, the value at which the base ink 36b is used when at least one colored ink 36a of C, M, Y, and K is used. The color conversion unit 12 refers to the color conversion LUT and converts the RGB data to each pixel, for example, two of C, M, Y, K, and W. 8 The data is converted into ink quantity data having integer values ​​for gradation. The ink quantity data represents the amount of C, M, Y, K, and W ink 36 used per pixel. Note that the ink 36 shown in Figure 5 includes colored inks 36a of C, M, Y, and K, as well as undercoat ink 36b. If the resolution of the RGB data is different from the print resolution, the color conversion unit 12 first converts the resolution of the RGB data to the print resolution, or converts the resolution of the ink quantity data to the print resolution.

[0032] The halftone processing unit 13 generates dot data with a reduced number of gradations, for example, to 2 or 4, by performing halftone processing on the ink amount data using one of the following methods: dithering, error diffusion, etc. Dot data is generated for each of C, M, Y, K, and W. The dot data represents the formation state of the ink dots 36 in pixel units. The rasterization processing unit 14 generates raster data by performing a rasterization process that rearranges the dot data in the order in which the dots are formed by the drive unit 50.

[0033] The drive signal transmission unit 15 generates a drive signal SG1 from the raster data that corresponds to the voltage signal applied to the drive element 42 of the print head 30, and outputs it to the drive circuit 41 of the print head 30. RAM21 stores image data DA1 and the like received from the host device HO1. Communication I / F22 inputs and outputs information to and from the host device HO1. Examples of host devices HO1 include personal computers, tablet terminals, mobile phones such as smartphones, etc. Storage unit 23 may be a non-volatile semiconductor memory such as flash memory, or a magnetic storage device such as a hard disk. Operation panel 24 includes an output unit 25 such as a liquid crystal panel for displaying information, an input unit 26 such as a touch panel for receiving operations on the display screen, etc.

[0034] The drive circuit 41 applies a voltage signal to the drive element 42 according to the drive signal SG1 input from the drive signal transmission unit 15. The drive element 42 may be a piezoelectric element that applies pressure to the ink 36 in a pressure chamber communicating with the nozzle 34, or it may be a drive element that generates bubbles in the pressure chamber by heat to eject ink droplets 37 from the nozzle 34. Ink 36 is supplied to the pressure chamber of the print head 30 from the ink cartridge 35. The ink 36 in the pressure chamber is ejected as ink droplets 37 from the nozzle 34 toward the transfer medium M1 by the drive element 42. When the ink droplets 37 land on the transfer medium M1, dots are formed on the transfer medium M1. When dots of colored ink 36a are formed on the transfer medium M1, an image IM1 represented by a pattern of dots is formed on the transfer medium M1.

[0035] The print head 30 shown in Figure 4 includes a colored ink head 31 that ejects colored ink 36a and a base ink head 32 that ejects base ink 36b. The colored ink 36a is an ink that contains a colorant, such as a pigment, as a dispersed phase or solute in a liquid (e.g., water) as a dispersion medium or solvent. The colored ink 36a includes, for example, chromatic inks of C, M, and Y, and achromatic ink of K. The colored ink head 31 includes a C ink head 31C that ejects C ink, an M ink head 31M that ejects M ink, a Y ink head 31Y that ejects Y ink, and a K ink head 31K that ejects K ink. The base ink 36b is an ink that contains a component that blocks light transmission, for example, a W ink that contains a component that diffusely reflects light. The W ink is an ink that contains, for example, a white pigment such as titanium dioxide or zinc oxide as a dispersed phase in a liquid such as water as a dispersion medium. Each ink head (31C, 31M, 31Y, 31K, 32) has a nozzle row in which multiple nozzles 34 are arranged in a nozzle alignment direction that intersects the scanning direction D3, for example, in the transport direction D1. The multiple nozzles 34 of each ink head may be arranged in a staggered pattern in the nozzle alignment direction, in other words, in two rows in the nozzle alignment direction. The nozzle alignment direction may be perpendicular to the transport direction D1, or it may be offset from the transport direction D1 by a range of less than 90°. Each nozzle 34 of the colored ink head 31 ejects colored ink 36a as an ink droplet 37, and each nozzle 34 of the undercoat ink head 32 ejects undercoat ink 36b as an ink droplet 37. The print head 30 shown in Figures 3A and 34 is mounted on a carriage 33. When the printer 2 performs lateral printing, the carriage 33 is movable along, for example, the scanning direction D3 as the main scanning direction and the transport direction D1 as the sub-scanning direction.

[0036] The drive unit 50, as a lateral system, includes a main scanning drive unit 51, a sub-scanning drive unit 52, and a transport unit 55. The main scanning drive unit 51 shown in Figure 3A works in cooperation with the control unit 10 to perform a main scan, which involves moving the print head 30 along the scanning direction D3, which is also the width direction D2 of the transfer medium M1, and ejecting ink 36 from the print head 30 in at least one of the forward direction D11 and the return direction D12. The sub-scanning drive unit 52 shown in Figure 3A works in cooperation with the control unit 10 to perform a sub-scan, which involves moving the print head 30 along the transport direction D1, which is the sub-scanning direction, between main scans.

[0037] The transport unit 55 shown in Figures 3A and 3B includes a transport roller pair 60, which includes a drive roller 61 and a driven roller 62. The driven roller 62 is an example of a roller as a pressurizing unit 3, and a predetermined pressure is applied toward the drive roller 61 by an elastic body (not shown), such as a spring. The transport roller pair 60 refers collectively to the transport roller pair 60a and 60b, the drive roller 61 refers collectively to the drive rollers 61a and 61b, and the driven roller 62 refers collectively to the first roller 62a and the second roller 62b. Here, the transfer medium M1 is transported from upstream S1 to downstream S2 in the transport direction D1. The transport roller pair 60a is upstream S1 from the print head 30, and the transport roller pair 60b is upstream S1 from the transport roller pair 60a. The drive roller 61 is in contact with the back surface of the transfer medium M1, i.e., the support layer 71 (see Figure 2). The driven roller 62 is in contact with the surface surface of the transfer medium M1, i.e., the ink receiving layer 72. The downstream transport roller pair 60a includes a plurality of first rollers 62a arranged at intervals in the width direction D2 intersecting the transport direction D1, for example, in the width direction D2 perpendicular to the transport direction D1. The upstream transport roller pair 60b includes second rollers 62b located in a different position from the plurality of first rollers 62a in the transport direction D1. The second rollers 62b are positioned to block the space between the first rollers 62a when viewed from the transport direction D1. Thus, the plurality of rollers (62a, 62b) are arranged in a staggered pattern. Figure 3A shows the portion A2 in the printing area A0 where each first roller 62a is in contact with the ink receiving layer 72, and the portion A1 where none of the first rollers 62a are in contact with the ink receiving layer 72.

[0038] In this specific example, the pressure applied by the second roller 62b to the ink receiving layer 72 is equal to the pressure applied by the multiple first rollers 62a to the ink receiving layer 72. The pressure applied by the rollers (62a, 62b) to the ink receiving layer 72 can be adjusted, for example, by fine-tuning the position of each elastic body. Furthermore, it is possible to adjust the pressure applied by the rollers (62a, 62b) to the ink receiving layer 72 by designing the materials of the multiple first rollers 62a and the second rollers 62b separately.

[0039] The transport unit 55 described above works in cooperation with the control unit 10 to transport the transfer medium M1, which is continuous paper, along the transport path 59 in the transport direction D1 during printing in the printing area A0. As shown in Figure 5, the transport unit 55 may be equipped with a pair of discharge rollers located downstream S2 from the print head 30.

[0040] The platen 58 is located below the transport path 59 and supports the transfer medium M1 by contacting it in the transport path 59. The print head 30, controlled by the control unit 10, ejects ink droplets 37 toward the transfer medium M1 supported by the platen 58, thereby adhering ink 36 to the transfer medium M1. The control unit 10 controls the ejection of ink from the print head 30 and the drive unit 50.

[0041] Furthermore, the base ink head 32 can be positioned in various ways, as long as the base ink 36b can be superimposed on the image IM1 created by the colored ink 36a. For example, the base ink head 32 may be positioned in the forward direction D11 from the C ink head 31C shown in Figure 4, or it may be positioned in the direction opposite to the sub-scanning direction from the colored ink head 31.

[0042] Next, the printing method on the transfer medium M2 will be explained with reference to Figures 1-6. This printing method includes the following steps. (c1) Pressurization step ST1 in which the ink receiving layer 72 is pressurized by the driven roller 62. (c2) Scanning step ST3, in which the carriage 33 is moved in the scanning direction D3. (c3) Recording step ST2 in which, in the ink receiving layer 72, ink droplets 37 are not ejected from the print head 30 to the portion A3 that is not pressurized by the driven roller 62, and colored ink 36a is ejected from the colored ink head 31 to the portion (parts A1, A2) that is pressurized by the driven roller 62. As a result, an image IM1 is formed in the ink receiving layer 72. The image IM1 can be said to include the ink receiving layer 72, and the quality of the image IM1 is affected by the state of the ink receiving layer 72. (c4) Substrate forming process ST4 in which the base ink 36b is superimposed on the image IM1 by ejecting the base ink 36b from the base ink head 32. (c5) An adhesive application step ST5 in which adhesive 111 is attached to the base ink 36b superimposed on the image IM1 formed on the transfer medium M1. (c6) Heating step ST6 to heat the transfer medium M1 to which the adhesive 111 has been applied. (c7) Transfer step ST7, in which the image IM1 is transferred to the transfer medium M2 by adhering the adhesive 111 to the transfer medium M2.

[0043] In the pressurization step ST1, the transport roller pair 60 nip the transfer medium M1 and transport it in the transport direction D1. This causes the driven roller 62 to pressurize the ink receiving layer 72. The portion of the ink receiving layer 72 that has been pressurized by the driven roller 62 moves to a position that can face the nozzle surface 30a of the print head 30, i.e., to the print area A0. As shown in Figure 6, in the scanning step ST3, the colored ink head 31 moves in the scanning direction D3, and in the recording step ST2, the colored ink head 31 ejects colored ink 36a into the print area A0, forming the image IM1 in the print area A0. In this specific example, the sub-scanning is performed by the sub-scanning drive unit 52, completing the image IM1 in the print area A0. Furthermore, in the scanning step ST3, the base ink head 32 moves in the scanning direction D3, and in the base formation step ST4, the base ink head 32 ejects base ink 36b into the print area A0, superimposing the base ink 36b onto the image IM1.

[0044] In the example shown in Figure 1, the transfer medium M1, on which the image IM1 and base ink 36b are superimposed, is intermittently transported from the printer 2 to the adhesive application device 100, and tilted into the adhesive tank 110. If the adhesive tank 110 contains powdered adhesive 111, the adhesive 111 adheres to the base ink 36b, which is still wet. Figure 6 shows the state in which, in the adhesive application process ST5, the image IM1, base ink 36b, and powdered adhesive 111 are sequentially layered on the transfer medium M1. In the example shown in Figure 1, the transfer medium M1 to which the thermoplastic adhesive 111 has been applied is intermittently transported from the adhesive tank 110 to the heating unit 120. In the heating process ST6, the heating unit 120 heats the transfer medium M1 to which the adhesive 111 has been applied. When the transfer medium M1 is heated above the temperature at which the adhesive 111 melts, the adhesive 111 melts. Figure 6 shows a state in which the image IM1, dried base ink 36b, and molten adhesive 111 are sequentially layered on the transfer medium M1. If the thermal transfer apparatus 200 can heat the transfer medium M1, the heating unit 120 may preheat the transfer medium M1 to a temperature below the melting point of the adhesive 111. In the example shown in Figure 1, the heated transfer medium M1 is intermittently discharged from the heating unit 120. The discharged transfer medium M1 is cut as needed, placed on top of the transfer medium M2 with the adhesive 111 applied side facing the transfer medium M2, and then fed into the thermal transfer apparatus 200.

[0045] In the transfer process ST7, the thermal transfer apparatus 200 pressurizes the transfer medium M1 and the transfer medium M2 so that the adhesive 111 applied to the transfer medium M1 is in contact with the transfer medium M2. If the thermal transfer apparatus 200 is equipped with a heating mechanism, the thermal transfer apparatus 200 heats the transfer medium M1 and the transfer medium M2 to a temperature above the melting temperature of the adhesive 111. Figure 6 shows a state in which the molten adhesive 111, dried base ink 36b, image IM1, and transfer medium M1 are sequentially laminated on the transfer medium M2. By pressurizing the transfer medium M1 and the transfer medium M2, the image IM1 adheres to the transfer medium M2 via the base ink 36b and adhesive 111. When the support layer 71 is peeled off from the transfer medium M2, the image IM1 and dried base ink 36b remain on the transfer medium M2, and a transfer medium M2 with the image IM1 transferred is obtained as shown in Figure 1. The transferred image IM1 is affected by the state of the ink-receiving layer 72. Although the transfer medium M1 described above is continuous paper, the transfer medium M1 may also be single sheets of paper. In this case, the user may place a printed single sheet of paper into the adhesive tank 110 to adhere the powdered adhesive 111 to the base ink 36b.

[0046] In the comparative example shown in Figure 10, when the printed image IM1, which was printed to have a uniform density, was examined, it was found that the density differed between the contact area A92 of the driven roller 62 and the non-contact area A91 of the driven roller 62. When the driven roller 62 contacts the ink receiving layer 72, the ink receiving layer 72 is pressed by being sandwiched between the drive roller 61 and the driven roller 62. From this, it is thought that the color development of the ink 36 changes due to changes in the particle structure, such as the crushing of the ink receptor particles 73 contained in the ink receiving layer 72, at the contact area A92, resulting in unevenness in density in the image IM1.

[0047] In the specific example shown in Figure 3A, in the ink receiving layer 72, the portion A1 that is not pressurized by the multiple first rollers 62a within the entire range where ink droplets 37 are ejected from the print head 30 is pressurized by the second roller 62b. It can also be said that the multiple first rollers 62a level the particles of the ink receptor 73 in the contact area A2, and the second roller 62b level the particles of the ink receptor 73 in the contact area A1. The portions A1 and A2 of the ink receiving layer 72 that are pressurized by the rollers (62a, 62b) are transported in the transport direction D1, and then ink droplets 37 are ejected from the print head 30 to these portions A1 and A2. In the ink receiving layer 72, ink droplets 37 are not ejected from the print head 30 to the portion A3 that is not pressurized by the pressurizing section 3, but ink droplets 37 are ejected from the print head 30 to the portions A1 and A2 that are pressurized by the pressurizing section 3. As a result, the image IM1 is printed on the ink receiving layer 72, which is always under pressurization. Figure 3A shows that in image IM1, the density of parts A1 and A2, which are pressurized by the pressurizing section 3, is matched to the density of part A92 in Figure 10. This is thought to be because the non-contact part A1 of the first roller 62a, like the contact part A2 of the first roller 62a, experienced a change in the color development of the ink 36 due to a change in the particle structure, such as the crushing of the ink receptor particles 73 contained in the ink receiving layer 72. As explained above, this specific example can suppress unevenness in print density caused by the presence or absence of pressure in the ink receiving layer 72. This effect is achieved not by improvements to the printing medium but by improvements to the structure of the printer 2, making it possible to use a wide variety of printing media. As a result, the transport accuracy of the printing medium is improved, and compatibility with printing media is enhanced. It is presumed that the stable transport of the printing medium will make it less likely for the printing medium to skew.

[0048] Furthermore, when the pressure applied by the second roller 62b to the ink receiving layer 72 is equal to the pressure applied by the multiple first rollers 62a to the ink receiving layer 72, the ink receiving layer 72 is continuously pressurized with equal pressure in the width direction D2. This further suppresses unevenness in the print result due to the presence or absence of pressurization of the ink receiving layer 72. Furthermore, the number of first rollers 62a may be 3 or more. In this case, the number of second rollers 62b may be 2 or more.

[0049] (3) Second specific example: Figure 7A is a schematic plan view illustrating the configuration of the printer 2 according to the second specific example. Figure 7B is a schematic side view illustrating the configuration of the transport unit 55 shown in Figure 7A. In Figures 7A and 7B, elements that are the same as or similar to the elements shown in Figures 3A and 3B may be denoted by the same reference numerals and their explanations may be omitted. The transport roller pair 60 shown in Figures 7A and 7B is a single set, and the driven roller 62, acting as the pressurizing unit 3, is continuous across the entire range of the printing area A0 in the width direction D2. Therefore, it can be said that the driven roller 62 is continuous across the entire range in the width direction D2 over which ink droplets 37 are ejected from the print head 30 to the ink receiving layer 72. Since the transport roller pair 60 is located upstream S1 from the print head 30, when the transport unit 55 transports the transfer medium M1 in the transport direction D1, the portion of the ink receiving layer 72 pressurized by the driven roller 62 moves to the printing area A0. Therefore, in the pressurizing process ST1, the transfer medium M1 is transported in the transport direction D1, and the portion A2 of the ink receiving layer 72 pressurized by the driven roller 62 is transported in the transport direction D1, after which ink droplets 37 are ejected from the print head 30 to the aforementioned portion A2 in the recording process ST2.

[0050] In the above case, the entire area in the ink receiving layer 72 over which ink droplets 37 are ejected from the print head 30 is pressurized by the driven roller 62. Therefore, the second specific example can also suppress unevenness in the print result due to the presence or absence of pressurization in the ink receiving layer 72. Furthermore, since only one pair of transport rollers 60 is required, the second specific example can be made simpler in structure compared to the first specific example.

[0051] (4) A third specific example: Figure 8 schematically illustrates the carriage 33 of printer 2 in a third specific example. The carriage 33 shown in Figure 8 is equipped with a print head 30 and a pressure unit 3. Therefore, in the scanning process ST3, the main scanning drive unit 51 shown in Figure 5 moves the carriage 33, equipped with the print head 30 and the pressure unit 3, in the scanning direction D3. The pressure unit 3 is equipped with movable rollers 38a and 38b, and lifting units 39a and 39b that lift the rollers 38a and 38b, respectively. Note that roller 38 refers collectively to the forward roller 38a and the return roller 38b, and lifting unit 39 refers collectively to the forward lifting unit 39a and the return lifting unit 39b. The forward roller 38a and the forward lifting unit 39a are located in the forward direction D11 from the print head 30. The return roller 38b and the return lifting unit 39b are located in the return direction D12 from the print head 30. The length of the roller 38 in the transport direction D1 is greater than or equal to the length of the nozzle row in the transport direction D1. Therefore, the descending roller 38 contacts the entire area in the ink receiving layer 72 where the ink droplets 37 ejected from the print head 30 land. When the carriage 33 moves in the forward direction D11, the forward roller 38a pressurizes the ink receiving layer 72 while the return roller 38b is separated from the ink receiving layer 72. When the carriage 33 moves in the reverse direction D12, the return roller 38b pressurizes the ink receiving layer 72 while the forward roller 38a is separated from the ink receiving layer 72.

[0052] Based on the above, the print head 30 provided on the carriage 33 ejects ink droplets 37 in the ink receiving layer 72 to the area pressurized by the pressurizing section 3 provided on the carriage 33.

[0053] Figure 9 schematically illustrates the roller lifting and lowering control process performed by the control unit 10 shown in Figure 5. When the control unit 10 receives a print command for image IM1 from the host device HO1, the operation panel 24, or the like, it starts the roller lifting and lowering control process. First, when the control unit 10 starts the main scan of the forward path, which moves the carriage 33 in the forward direction D11, it controls the lifting and lowering unit 39 to lower the forward path roller 38a while the return path roller 38b is raised (step S102). At the end of the main scan of the forward path, the control unit 10 controls the forward path lifting and lowering unit 39a to raise the forward path roller 38a (step S104). Sub-scans between main scans are performed while both rollers (38a, 38b) are raised.

[0054] After step S104, when the control unit 10 starts the main scan of the return path to move the carriage 33 in the return direction D12, it controls the lifting unit 39 to lower the return path roller 38b while keeping the forward path roller 38a raised (step S106). At the end of the main scan of the return path, the control unit 10 controls the return path lifting unit 39b to raise the return path roller 38b (step S108). After step S108, the control unit 10 determines whether or not printing of image IM1 is finished (step S110). If printing continues, sub-scans are performed between main scans, and the control unit 10 repeats the processes of steps S102 to S110. If printing is finished, the control unit 10 terminates the roller lifting and lowering control process.

[0055] In the above case, ink droplets 37 are ejected from the print head 30 on the carriage 33 to the areas of the ink receiving layer 72 that are pressurized by the roller 38 on the carriage 33. As a result, the image IM1 is printed on the ink receiving layer 72, which is always under pressure. Therefore, the third specific example can also suppress unevenness in the print result due to the presence or absence of pressure on the ink receiving layer 72. Furthermore, even if the driven roller 62 of the printer 2 can only pressurize a portion of the print area A0, the aforementioned unevenness in density can be suppressed.

[0056] (5) Variations: Various modifications of this invention are conceivable. For example, the printing medium may be paper as a support layer 71 and printing paper having an ink receiving layer 72. Furthermore, the present invention also includes cases where the base ink 36b is not superimposed on the image IM1. The printing method for the print medium is not limited to lateral printing; serial printing or line printing are also acceptable. The color combination of the colored ink 36a is not limited to C, M, Y, and K, and may include orange, green, light cyan at a lower concentration than C, light magenta at a lower concentration than M, dark yellow at a higher concentration than Y, light black at a lower concentration than K, etc. Of course, the embodiments of this application can also be applied when the colored ink 36a does not include some of the colors C, M, Y, and K. The base ink 36b is not limited to W ink; K ink, gray ink, light-transmitting clear ink, etc., may also be used. The entity performing the above-described processing is not limited to the CPU; it may also be an electronic component other than the CPU, such as an ASIC (Application Specific Integrated Circuit). Of course, multiple CPUs may cooperate to perform the above-described processing, or a CPU and another electronic component (such as an ASIC) may cooperate to perform the above-described processing.

[0057] The pressurizing section 3 may also be a drive roller 61. For example, the transport roller pair 60 may include a drive roller 61 that contacts the support layer 71.

[0058] (6) Conclusion: As described above, according to the present invention, in various embodiments, it is possible to provide a printing method and other configuration that can suppress unevenness in the density of the printed result due to the presence or absence of pressure on the ink receiving layer. Of course, even in embodiments consisting only of the constituent elements of the independent claims, the basic functions and effects described above can be obtained. Furthermore, configurations obtained by substituting or changing the combinations of each configuration disclosed in the above-mentioned examples, configurations obtained by substituting or changing the combinations of each configuration disclosed in the prior art and the above-mentioned examples, etc., are also possible. The present invention also includes these configurations, etc. [Explanation of Symbols]

[0059] 1...Printing device, 2...Printer, 3...Pressurizing unit, 10...Control unit, 20...Printing unit, 30...Print head, 33...Carriage, 34...Nozzle, 36...Ink, 37...Ink droplet, 38...Roller, 39...Lifting unit, 50...Drive unit, 51...Main scanning drive unit, 52...Sub-scanning drive unit, 55...Transport unit, 60...Transport roller pair, 61...Drive roller, 62...Driven roller, 62a...First roller, 62b...Second roller, 71...Support layer, 72...Ink receiving layer, 73...Ink receptor, A0...Printing area, A1, A2, A3...Part, D1...Transport direction, D2...Width direction, D3...Scanning direction, D11...Forward direction, D12...Reverse direction, IM1...Image, M1...Transfer medium, M2...Transfer medium, S1...Upstream, S2...Downstream, ST1...Pressurizing process, ST2...Recording process, ST3...Scanning process.

Claims

1. A printing method comprising ejecting ink droplets from a print head onto a printing medium having an ink-receiving layer on its surface containing dispersed ink receptors, A pressurizing step in which the ink receiving layer is pressurized by a pressurizing section that contacts the ink receiving layer, In the ink receiving layer, the ink droplets are not ejected from the print head to the portion not pressurized by the pressurizing section, and the ink droplets are ejected from the print head to the portion pressurized by the pressurizing section. Printing methods, including those mentioned.

2. The printing method according to claim 1, wherein the ink receiving layer contains at least one of silica particles and alumina particles as the ink acceptor.

3. In the pressurizing step, the printing medium is conveyed in the conveying direction by a conveying unit that includes a plurality of rollers as the pressurizing unit. In the recording process, the area pressurized by the plurality of rollers is transported in the transport direction, and then the ink droplets are ejected from the print head to that area. The plurality of rollers include a plurality of first rollers arranged at intervals in the width direction intersecting the conveying direction, and a second roller located in a position different from the plurality of first rollers in the conveying direction. The second roller pressurizes the portion of the ink receiving layer that is not pressurized by the plurality of first rollers, within the entire range in which the ink droplets are ejected from the print head. The printing method according to claim 1 or claim 2.

4. The printing method according to claim 3, wherein the pressure applied by the second roller to the ink receiving layer is equal to the pressure applied by the plurality of first rollers to the ink receiving layer.

5. In the pressurizing step, the printing medium is conveyed in the conveying direction by a conveying unit including rollers as the pressurizing unit. In the recording process, the area pressurized by the roller is transported in the transport direction, and then the ink droplets are ejected from the print head to that area. The roller is continuous in the width direction intersecting the transport direction over the entire range over which the ink droplets are ejected from the print head to the ink receiving layer. The printing method according to claim 1 or claim 2.

6. The process further includes a scanning step of moving the print head and the carriage on which the pressurizing unit is provided in the scanning direction. In the ink receiving layer, the ink droplets are ejected from the print head provided on the carriage to the location pressurized by the pressurizing section provided on the carriage. The printing method according to claim 1 or claim 2.

Images