Printing device and method for producing printed matter

Abstract

The purpose of the present invention is to obtain a printing device and a method for producing printed matter that make it possible to obtain an ink layer in which the intensity of a printed image formed on the surface of a piece of printed matter is high, without the need for large-scale equipment. A printing device according to the present invention comprises: a printing pad that has a printing surface which deforms following the shape of a printing surface of a piece of printed matter; a printing original plate that comprises a placement surface on which ink is placed; a printing original plate stage that the printing original plate is placed on; and an ink placement device that places the ink on the surface of the printing original plate. The printing pad is configured so as to be movable between the printing original plate stage and the piece of printed matter, and so as to be pressed against the printing original plate stage or the piece of printed matter. The ink placement device comprises a screen that an opening which the ink passes through is formed on, and a squeegee that slides on the surface of the screen.

Description

Printing device and method for producing printed matter

[0001] The present invention relates to a printing device and a method for manufacturing a printed matter, and more particularly to a printing device and a method for manufacturing a printed matter by moving a printing pad and pressing a printing surface against a surface to be printed.

[0002] Printing devices using a printing pad are known as devices for printing images such as letters and pictures. The printing device presses the printing surface of the printing pad against a printing plate, transfers ink placed on the printing plate according to a printing pattern to the printing pad, and presses the printing surface of the printing pad with the ink transferred onto the printing surface against the printing surface, thereby printing the printing pattern on the printing surface. The printing plate is formed so that ink is placed on its surface by, for example, an inkjet, or is engraved with a fine dot pattern and holds ink in recessed or raised portions. The printing pad is pressed against the printing plate to transfer the ink (see, for example, Patent Document 1).

[0003] In addition, in conventional automobile body painting, for example, a substrate is subjected to an electrodeposition coating and baking as a primer coat, followed by an intermediate coat, baking, a base coat, a clear top coat, and baking. The base coat contains, for example, a resin component and a pigment component, and uses a water-soluble or water-dispersible paint such as an emulsion, or an organic solvent-based paint. The coating is applied by, for example, an air spray method, an airless spray method, an electrostatic coating method, or a bell coating method, and the paint is sprayed onto the automobile body using a painting robot. After a paint layer is formed on the automobile body, the coating is baked (see, for example, Patent Document 2).

[0004] Patent No. 7297141 Patent No. 7091385

[0005] However, while the printing using fine ink dots disclosed in Patent Document 1 is suitable for transferring a fine image to the surface of a printed material, when printing on the surface of an automobile body, for example, there is a problem that the strength and durability of the ink layer formed on the surface is insufficient with ink with fine dots. On the other hand, in the painting of automobile bodies disclosed in Patent Document 2, the paint is sprayed in a mist form, so a ventilation system and a treatment system for the ventilated air are required in the painting booth, and there is a problem that large-scale equipment other than the painting equipment is required.

[0006] The present invention solves the above-mentioned problems, and aims to provide a printing device and a method for producing printed matter that do not require large-scale equipment and that can produce an ink layer with high strength in the printed image formed on the surface of the printed matter.

[0007] The printing device of the present invention comprises a printing pad having a printing surface that deforms to follow the shape of the printing surface of the printed material, a printing plate having a mounting surface on which ink is placed, a printing plate stage on which the printing plate is placed, and an ink mounting device that places ink on the surface of the printing plate, wherein the printing pad is configured to be able to move freely between the printing plate stage and the printed material and is configured to be pressed against the printing plate stage or the printed material, and the ink mounting device comprises a screen having openings formed therein through which ink passes, and a squeegee that slides over the surface of the screen.

[0008] The method for manufacturing a printed matter according to the present invention is a method for manufacturing a printed matter in which the printing surface of a printing pad is pressed against the printing surface of a printed matter to transfer the ink placed on the printing surface and form an ink layer on the printing surface, and comprises an ink placing step in which, after the ink is placed on a screen, a squeegee is slid along the surface of the screen and the ink is passed through openings formed in the screen to place the ink on the surface of the printing plate; a transfer step in which the printing surface is pressed against the printing plate on which the ink has been placed and the ink on the printing plate is transferred to the printing surface; and a pressing step in which the printing surface is pressed against the surface of the printed matter while deforming it to follow the surface of the printed matter, thereby forming the ink layer.

[0009] According to the present invention, ink is applied to a printing plate using a screen and squeegee, and then transferred to a printing pad and then to the printing surface of a printed product, thereby forming an ink layer on the printing surface without atomizing the paint. Furthermore, because the ink is applied to the printing plate using a screen, the ink transferred from the printing plate to the printing pad can be made thick, and the ink layer formed on the printing surface can also be made thick enough, enabling printing with high strength and durability. The ink used in the present invention is not limited to conventional paints, and any ink that can pass through the holes in the screen can be used, providing a wide range of materials to choose from.

[0010] 5 is a schematic diagram of printing using a printing pad 10 on a print object 70 according to embodiment 1. FIG. 6 is a side view showing an example of a printing device 100 according to embodiment 1. FIG. 7 is a cross-sectional view showing an example of a printing pad 10 provided in the printing device 100 according to embodiment 1. FIG. 8 is a schematic diagram of a cross-sectional structure of an ink placement device 20 according to embodiment 1. FIG. 9 is a schematic diagram of a process of placing ink 40 on a printing plate 50 using the ink placement device 20 of FIG. 4. FIG. 10 is an example of a detailed structure of a screen 21 according to embodiment 1. FIG. 11 is a flow chart of a method for manufacturing a print object 70 using the printing device 100 according to embodiment 1. FIG. 12 is a flow chart of the operation of the printing device 100 according to embodiment 1. FIG. 13 is a detailed flow chart of the operation of the ink placement process (S1) according to embodiment 1. FIG. 14 is a modified example of the printing pad 10 used in the printing device 100 according to embodiment 1. FIG. 15 is an enlarged schematic diagram of a printing surface 4 of the printing pad 10 according to embodiment 1.

[0011] Embodiment 1. A printing apparatus and a method for producing printed matter according to the present invention will be described below with reference to the drawings. Note that the present invention is not limited to the embodiments described below. In addition, the same parts in each drawing are given the same reference numerals, and some explanations will be omitted. Furthermore, each drawing is a schematic drawing, and the present invention is not limited to the shapes shown in the drawings.

[0012] <Printed Object 70> FIG. 1 is a schematic diagram of a case where a printing pad 10 is used to print on a printed object 70 according to the first embodiment. The printed object 70 is, for example, an automobile body, door, or hood. An automobile body, for example, is constructed by plastically deforming metal and joining it by means such as welding. After cleaning, surface treatment, plating, and other processes, the surface is painted. The surface of an automobile body, for example, is constructed by assembling curved surfaces, and conventionally, painting is performed by spraying paint onto the surface using means such as an air sprayer. In the first embodiment, a case where an ink layer is formed on an automobile body using a printing pad 10 is described. Note that the shape of the printed object 70 shown in FIG. 1 is merely an example, and the shape of the printing surface 70a can be changed as appropriate. Furthermore, the printed object 70 is not limited to an automobile body, and can be changed as appropriate depending on the material and the surface treatment applied to the printing surface 70a.

[0013] <Printing Device 100> FIG. 2 is a side view illustrating an example of a printing device 100 according to the first embodiment. The printing device 100 includes a printing pad 10 that can move linearly in the vertical direction. The printing pad 10 is moved up and down by a vertical movement device 11 included in the printing device 100, and the printing surface 4 is pressed against the printing surface of the object 70 to be printed. In the first embodiment, the printing pad 10 is pressed against the printing surface 70a. The printing device 100 also includes a horizontal movement device 12. The horizontal movement device 12 moves the printing pad 10 and the vertical movement device 11 in the horizontal direction. Note that while the printing pad 10 is shown in FIG. 2 to be pressed against the printing surface 70a by moving linearly up and down, it may also be configured to be pressed against the printing surface 70a by moving horizontally, for example. The printing pad 10 may also be moved and pressed against the printing surface 70a using a robot arm or the like. In this case, for example, the printing pad 10 is attached to a robot equipped with a multi-jointed arm instead of the vertical movement device 11 and the horizontal movement device 12, and the printing pad 10 is configured to move between the printing plate 50 and the printed matter 70.

[0014] The printing pad 10 is moved by the horizontal movement device 12 above the print object 70, as well as the cleaning device 60, activating device 61, air blowing device 62, or printing blank 50. The printing pad 10 is moved up and down by the vertical movement device 11, and the printing surface 4 is pressed against the print object 70, cleaning device 60, activating device 61, or printing blank 50, respectively. In FIG. 2 , the printing apparatus 100 has, from the left, an area where the print object 70 is placed, a surface treatment stage 86 equipped with the cleaning device 60, and a printing blank stage 85. The surface treatment stage 86 is equipped with the activating device 61 and the air blowing device 62. The printing blank 50 is placed on the printing blank stage 85. However, in the printing apparatus 100, these stages can be freely positioned and can be appropriately changed to suit the convenience of the operator and the location where the printing apparatus 100 is installed. Furthermore, the cleaning device 60, activation device 61, and air blow device 62 of the printing device 100 may not be installed in the printing device 100. Furthermore, a stage and a jig for placing the printed matter 70 may be arranged in the area where the printed matter 70 is placed.

[0015] <Printing Pad 10> FIG. 3 is a cross-sectional view showing an example of the printing pad 10 included in the printing device 100 according to the first embodiment. FIG. 3 shows a cross section passing through the top 6 of the printing pad 10 and perpendicular to the plane 13 on which the substrate 5 is fixed. The printing pad 10 shown in FIG. 3 is, for example, approximately hemispherical. However, the shape of the printing pad 10 is not limited thereto. The shape can be appropriately modified depending on the specifications of the printed object 70, for example, a bullet shape, a shape with a curved surface formed by rotating a parabola around its axis of symmetry, a shape obtained by cutting an ellipsoid, or a shape obtained by continuously extending a bullet-shaped or semicircular cross section in a straight line. The substrate 5 of the printing pad 10 includes an internal layer 1 and an external layer 2 covering the surface of the internal layer 1. However, the printing pad 10 is not limited to a two-layer structure and may have a single-layer structure or more layers. Furthermore, the outer surface of the internal layer 1 has a shape in which the outer surface of the external layer 2 is offset inward, but this is not limited to this, and the external surface of the internal layer 1 may have an uneven surface. Furthermore, a cavity may be provided inside the printing pad 10.

[0016] The printing pad 10 has a peak 6 that first comes into contact with the printing object 70 or the printing blank 50, and the peak 6 is configured as a dot or a line. This prevents air from getting trapped between the printing surface 4 and the printing object 70 or the printing blank 50 when the printing pad 10 is pressed against the printing object 70 or the printing blank 50, preventing gaps in the printed image applied to the printing object 70. In the first embodiment, a predetermined range of the surface of the printing pad 10, centered on the peak 6, becomes the printing surface 4 that transfers ink from the printing blank 50 and onto the printing object 70.

[0017] <Substrate 5> The substrate 5 is formed by molding, for example, silicone rubber. The substrate 5 is elastic (flexible) and is mixed with silicone oil to facilitate deformation. In the first embodiment, the substrate 5 has a substantially hemispherical shape, but the shape can be modified as appropriate depending on the specifications of the printed matter 70. The substrate 5 deforms when the printing pad 10 is pressed against the printing plate 50, and the printing surface 4 adheres closely to the surface of the printing plate 50, transferring the ink 41 placed on the mounting surface 51 of the printing plate 50 to the printing surface 4. The ink 41 placed on the mounting surface 51 of the printing plate 50 is arranged in correspondence with the image to be printed on the printed matter 70, forming a printing pattern corresponding to the image. Note that the material of the substrate 5 is not limited as long as it can transfer the ink 41 to the printing surface 70a when the printing pad 10 is pressed against the printing surface 70a.

[0018] For example, the substrate 5 may be formed from two materials with different hardnesses. In this case, for example, the material of the outer layer 2, which constitutes the portion close to the printing surface 4, is set to an Asker C hardness range of 10 to 20 points. The material of the inner layer 1, located inside the outer layer 2, is set to an Asker C hardness range of 20 to 40 points. The inner layer 1 is located on the side where a force pressing the printing surface 4 against the printing surface is applied during printing, and is located closer to the support member 7 than the outer layer 2. The support member 7 is connected to the vertical movement device 11 and transmits the force from the vertical movement device 11 to the printing pad 10. In order for the printing pad 10 to deform and follow the printing surface 70a, it is desirable to set the hardness of the printing pad 10 low. Therefore, the hardness of the portion of the printing pad 10 on the printing surface 4 side, which is pressed against the printing object 70, is set lower than that of the inner layer 1. This configuration makes it easier for the overall shape of the printing pad 10 to be maintained. At the same time, the outer layer 2, which is pressed directly against the surface to be printed, has the advantage of being easily deformed into the three-dimensional shape of the surface to be printed. However, the hardness of each part of the substrate 5 is not limited to the above hardness.

[0019] 2, a surface treatment stage 86 is disposed next to the printing stage 87 of the printing apparatus 100. A cleaning device 60 is installed on the surface treatment stage 86. The cleaning device 60 includes, for example, paper or adhesive tape. The printing surface 4 of the printing pad 10 is pressed against the surface of the paper or adhesive tape to remove ink 41, dirt, dust, etc. remaining after printing.

[0020] <Activation Device 61> The activation device 61 includes a reservoir tank for storing liquid and an absorption unit for absorbing and retaining the liquid. The printing surface 4 of the printing pad 10 is pressed against the surface of the absorption unit, causing the liquid retained by the absorption unit to adhere to the printing surface 4. The printing pad 10 facilitates the transfer of the ink 41 placed on the printing plate 50 to the printing surface 4 by adhering or impregnating the substrate 5 with water or a solvent. The liquid is appropriately selected based on the properties of the components contained in the ink 41 and has the property of softening hard ink 41. The ink 41 is a mixture of synthetic resins such as acrylic resin or urethane resin, and water, thinner, xylene, or toluene. It is preferable to select a liquid used in the activation device 61 that has a high affinity with the materials contained in the ink 41. However, the liquid used in the activation device 61 is not limited to the above.

[0021] The absorption unit of the activation device 61 is constructed, for example, by stacking thin sheet-like absorbent materials. The absorbent material is, for example, made of paper, but is not limited to paper and may be made of other materials, such as cloth or resin, as long as they absorb liquid. For example, the absorption unit may be constructed by stacking paper on a sponge-like resin. The surface of the absorption unit against which the printing surface 4 of the printing pad 10 is pressed may dry out, become contaminated with ink 41 or other contaminants remaining on the printing surface 4 of the printing pad 10, or the surface of the absorption unit may be scraped, causing the paper constituting the absorption unit to tear. Therefore, the top layer of paper in the absorption unit is designed to be peeled off and removed from the top layer of the absorption unit, and the stacked sheets may be removed one by one, or the upper layer may be replaced mechanically. However, the method for replacing the top layer of paper is not limited to this method. The absorption unit is configured so that the paper or the like that constitutes the top layer can be removed or replaced freely, so that the surface can be kept clean, and because it is permeated with liquid, the printing surface 4 of the printing pad 10 can be activated by pressing it against it. Note that the structure of the activation device 61 is not limited to the above, and other structures may also be used.

[0022] <Air blowing device 62> The air blowing device 62 adjusts the amount of water or solvent that has adhered to the printing surface 4 of the printing pad 10 by the activating device 61 to an appropriate amount. The air blowing device 62 blows air toward the printing surface 4 to remove excess water or solvent from the printing surface 4. Note that the type and number of the air blowing devices 62 and the direction in which the air is blown are not limited.

[0023] <Printing Plate Stage 85> The printing plate stage 85 has a printing plate 50 placed on its upper surface and is equipped with an ink placement device 20 that places ink on the printing plate 50. The ink placement device 20 places ink 41 on the surface of the printing plate 50 using a screen 21. The printing plate stage 85 is configured so that the printing plate 50 is placed thereon and the ink placement device 20 can be positioned above the printing plate 50 when placing the ink 41 on the printing plate 50. The printing plate stage 85 is also configured so that the ink placement device 20 can be retracted from above the printing plate 50 when transferring the ink 41 from the printing plate 50 to the printing pad 10. The ink placement device 20 may be configured to be movable horizontally or vertically at least above the printing plate 50 by a feed device (not shown). Alternatively, the printing plate 50 may be configured to be movable relative to the ink placement device 20. In either case, the ink placement device 20 or the printing plate 50 is configured to be movable to a position where it does not interfere with pressing the printing pad 10 against the printing plate 50. In Fig. 2, the printing plate 50 is placed on the printing plate stage 85, but it may also be configured so that the surface of the printing plate stage 85 functions as the printing plate, for example.

[0024] The printing plate stage 85 may be configured to be freely movable relative to the printing apparatus 100. For example, the printing plate stage 85 may be equipped with a device for movement, such as wheels, so that the layout can be freely changed relative to each device constituting the printing apparatus 100 as needed. In other words, the printing plate stage 85 may be moved and placed next to each device constituting the printing apparatus 100 other than the printing plate stage 85, and the printing plate stage 85 may be placed next to other printing apparatuses 100 as needed. In this case, the printing plate stage 85 may be provided with an ink placement device 20 and a printing plate 50, and the printing pad 10 may be pressed against the printing plate 50 by a robot arm or the like, or the printing plate 50 on which the ink 40 is placed may be supplied from the printing plate stage 85 to the main body of the printing apparatus 100. The movable printing plate stage 85 has the advantage that the ink placement device 20 and the printing plate 50 can be shared by multiple printing apparatuses 100, and a single ink placement device 20 can be used for multiple printing processes. The surface treatment stage 86 may also be configured to be movable, and each of the cleaning device 60, the activation device 61 and the air blow device 62 may also be configured to be movable.

[0025] <Ink Placement Device 20> Fig. 4 is a schematic diagram of the cross-sectional structure of the ink placement device 20 according to the first embodiment. Fig. 5 is a schematic diagram of a process for placing ink 40 on a printing plate 50 using the ink placement device 20 of Fig. 4. The ink placement device 20 is configured by fixing a screen 21 to a screen frame 22. The screen 21 is placed on the printing plate 50 as the ink 40 placed on the screen 21 passes through the openings 23. As shown in Fig. 5(a) , the ink 40 passes through the openings 23 as the squeegee 30 slides over the surface of the screen 21, and is placed on the surface of the printing plate 50. The squeegee 30 is a spatula-shaped member that slides with its tip pressed against the surface of the screen 21. The squeegee 30 is made of, for example, rubber or a resin material, and moves to scrape off the ink 40 on the screen 21 while pressing the screen 21 and the ink 40 against the printing plate 50 , thereby depositing the ink 41 on the surface of the printing plate 50 .

[0026] As shown in Figures 5(b) and (c), when the squeegee 30 moves while pressing against the screen 21 on which the ink 40 is placed, the ink 41 that passes through the openings 23 adheres to the printing plate 50, and the ink 41 is placed on the printing plate 50. If the multiple openings 23 are arranged with a sufficient distance between them, the ink 41 that passes through each of the multiple openings 23 is placed independently on the printing plate 50, as shown in Figure 5(b). Furthermore, if the viscosity of the ink 41 is low and the distance between the multiple openings 23 is small, the ink 41 is placed on the printing plate 50 without any gaps, as shown in Figure 5(c).

[0027] <Screen 21> Figure 6 shows an example of the detailed structure of the screen 21 according to the first embodiment. The screen 21 is formed, for example, by coating a mesh member 24 made of woven fibers with an emulsion 25. The emulsion 25 partially covers the mesh structure of the screen 21, forming portions of the screen 21 that are impermeable to the ink 40. The emulsion 25 is, for example, a liquid that hardens when exposed to UV light. The screen 21 is created by applying the emulsion 25 to the mesh member 24, masking it so that UV light is irradiated only in areas where the openings 23 are desired, irradiating the entire screen 21 with UV light, and removing the unhardened emulsion 25. In this manner, the mesh member 24 is formed with the openings 23 through which the ink 40 passes and portions through which the ink 40 does not pass.

[0028] The squeegee 30 slides over the surface of the screen 21, filling the openings 23 with ink 40 placed on the screen 21. As shown in FIG. 6 , the squeegee 30 is subjected to a load toward the screen 21 and slides over the screen 21, causing the ink 41 filled in the openings 23 to come into contact with the printing plate 50. This transfers the ink 41 to the printing plate 50. After the squeegee 30 presses the ink 41 against the printing plate 50 as shown in FIG. 6( a), when the screen 21 is released from the printing plate 50 as shown in FIG. 6( b), the ink 41 remains on the printing plate 50. The thickness of the ink 41 placed on the mounting surface of the printing plate 50 depends on the thickness h of the screen 21. For example, the ink 41 becomes thicker as the thickness h of the screen 21 increases, and the ink 41 becomes thinner as the thickness h of the screen 21 decreases.

[0029] In the case of a screen 21 obtained by coating a mesh member 24 with emulsion 25, the thickness h of the screen 21 is determined by the mesh member 24, which is made of woven fibers, and the coated emulsion 25. Because the mesh member 24 is made of fibers woven vertically and horizontally, its thickness includes not only the fibers 24a visible in the cross section shown in FIG. 6( a) but also the fibers 24b interwoven with the fibers 24a. The thickness h of the screen 21 represents the thickness of the mesh member 24 after it has been coated with emulsion 25. However, if the openings 23 provided in the screen 21 cover a wide area, the thickness h of the screen 21 may be the thickness of the mesh member 24. Furthermore, depending on the printed matter 70, the screen 21 may not have openings 23 in some areas, but may have openings 23 throughout the entire screen 21.

[0030] The mesh member 24 is formed by, for example, knitting resin fibers or metal fibers, and the gaps 24c between the woven fibers 24a and 24b form the openings 23. The mesh member 24 is configured, for example, so that the fibers 24a and 24b are arranged at equal intervals, and the spacing and the thickness of the fibers 24a and 24b are approximately equal. The mesh member 24 is not limited to being formed by knitting fibers, but may also be formed by crimping fibers extending vertically and horizontally together. The mesh member 24 may also be formed from a metal plate by providing multiple through-holes in the metal plate. Materials such as a resin plate or film can also be used for the mesh member 24 instead of a metal plate. When providing multiple through-holes in a metal plate, the multiple through-holes may be machined into the portions that will become the openings 23, for example, by laser processing. Alternatively, the openings 23 may be formed by coating an emulsion on a metal plate with multiple through-holes formed throughout the entire metal plate and fixing the emulsion in the portions other than the openings 23 to block some of the multiple through-holes. The emulsion may be any other material as long as it can be solidified to form the openings 23, for example, solidified ink or an adhesive may be used.

[0031] In the case of the screen 21 formed by providing a plurality of through holes in a thin metal plate, the thickness of the metal plate is the thickness h of the screen 21. In the case of the screen 21 formed by coating a thin metal plate with an emulsion 25, the combined thickness of the thin metal plate and the emulsion 25 is the thickness h of the screen 21. Even in the case of the screen 21 formed from a thin metal plate, if the openings 23 provided in the screen 21 cover a wide area, the thickness h of the screen 21 may be the thickness of the mesh member 24.

[0032] (Effect of Placing Ink 41 on Printing Plate 50 Using Screen 21) In printing using the screen 21 according to embodiment 1, it is possible to place ink 41 on printing plate 50 in a manner that corresponds to so-called solid printing (printing in which a predetermined printing area on the printing surface 70a of the print product 70 is completely filled with ink 41). For example, when using the printing device 100 according to embodiment 1, a relatively thick layer of ink 41 can be placed on printing plate 50 using the screen 21. The printing device 100 presses the printing pad 10 against printing plate 50 to transfer the ink 41 to the printing surface 4, and then presses the printing surface 4 with the transferred ink 41 against printing surface 70a, which has a curved or uneven surface, to form a layer of ink 41 on printing surface 70a. Because the printing device 100 according to embodiment 1 can place a relatively thick layer of ink 41 on printing plate 50, it is possible to form a thick layer of ink 41 on printing surface 70a. Furthermore, the structure of the openings 23 in the screen 21 allows the ink 41 to be used for so-called solid printing. As a result, the printing device 100 according to the first embodiment can form a uniform ink layer (paint layer) on the surface of, for example, an automobile body, and since it uses a high-viscosity ink (paint), splashing does not occur compared to conventional paints whose viscosity is reduced by a solvent such as thinner when applied by air spraying. Therefore, a painting line using such a printing device 100 can eliminate or reduce processing equipment such as ventilation systems and air purification systems, and the amount of paint (ink) used for painting can be reduced.

[0033] <Method for producing a printed matter using the printing device 100> A method for producing a printed matter 70 using the printing device 100 will be described below with reference to Figures 1, 2, and 5. As shown in Figure 2, the printing device 100 includes a control device 90. The control device 90 is configured, for example, by a microcomputer, and includes an arithmetic device 90a and a storage device 90b. The functions of the control device 90 are realized using the arithmetic device 90a and the storage device 90b (see Figure 2).

[0034] The storage device 90b may be a ROM that stores programs and data in advance, or a RAM for temporarily storing data when a program is executed. The storage device 90b may be, for example, a non-volatile or volatile semiconductor memory such as a flash memory, an EPROM (Erasable and Programmable ROM), or an EEPROM (Electrically Erasable and Programmable ROM). The storage device 90b may also be, for example, a removable recording medium such as a magnetic disk, a flexible disk, an optical disk, a CD (Compact Disc), an MD (Mini Disc), or a DVD (Digital Versatile Disc). The storage device 90b can store information obtained from the temperature sensor 68 and information processed by the arithmetic device 90a. In addition, the storage device 90b stores programs for the OS (Operating System), various application programs, data recorded in databases, etc., and these programs and data are processed by the CPU to realize various functions in cooperation with hardware resources.

[0035] The arithmetic unit 90a performs various processes to execute the functions of the control unit 90. For example, the arithmetic unit 90a compares room temperature information from a temperature sensor or the like with a temperature threshold previously stored in the storage unit 90b to determine whether the room temperature is higher than the threshold. If the room temperature is higher than the threshold, the control unit 90 performs control such as limiting the output of the heater of the air blower 66 to a predetermined value. Furthermore, if the room temperature is higher than the threshold, the control unit 90 may perform control such as shortening the operation time of the air blower 66, or limiting the time the printing pad 10 is stopped in front of the air blower 66 and exposed to air. Furthermore, the control unit 90 may perform control to change the printing conditions depending on the object 70 to be printed by the printing device 100. For example, if the printing surface 70a of the printing object 70 has a complex shape with irregularities, the control unit 90 may perform control to slow down the pressing speed of the printing pad 10 against the printing surface 70a. Additionally, the control unit 90 can be configured to appropriately control the operation of each element of the printing device 100.

[0036] 7 is a flow chart showing a method for producing a printed matter 70 by the printing device 100 according to embodiment 1. The method for producing a printed matter 70 will be outlined below with reference to FIG.

[0037] (Printing Plate Creation Process OP1) As shown in FIG. 7 , the method for producing a printed product begins with a printing plate creation process OP1 in which a print image is formed on the mounting surface 51 of the printing plate 50. In the printing plate creation process OP1, ink is placed on the printing plate 50 using the ink placement device 20 as shown in FIG. 5 . As shown in FIG. 2 , the printing plate 50 is, for example, flat and is placed on a printing plate stage 85. In the first embodiment, the printing plate 50 is a thin, flat plate made of aluminum alloy. However, a sheet material known as a "grain receiving sheet," which has excellent ink retention and affinity with the ink 41, can also be used. Furthermore, the ink retention and affinity can be improved by providing the sheet material with an uneven surface. The surface of the printing plate 50 is finished to a predetermined surface roughness so that the ink 41 can adhere from the openings 23 of the screen 21. However, even if the printing plate 50 is designed to have a high affinity with the ink 41, the material and structure are not limited. For example, the sheet material may not have an uneven surface. Furthermore, the surface of the printing plate stage 85 may serve as the printing plate 50 without using a printing plate 50 such as a sheet material.

[0038] Furthermore, the printing plate 50 may have a low affinity with the ink 41. When the printing method according to the first embodiment is used for painting automobile bodies, so-called solid printing is performed. In this case, a relatively large amount of ink 41 is applied to the printing plate 50. Therefore, when transferring the ink 41 from the printing plate 50 to the printing pad 10, some of the ink 41 on the printing plate 50 may remain on the printing pad 10 without being transferred. Using a printing plate 50 with a low affinity with the ink 41 has the advantage of improving the transfer rate of the ink 41 to the printing pad 10. For example, the printing plate 50 may be made of a film that has a low affinity with the ink 41. The printing plate 50 may also be coated on its surface with a fluororesin or may be processed to reduce its surface roughness. In other words, the printing plate 50 may be treated to reduce its affinity with the ink 41 depending on the material used in the ink 41. Furthermore, according to the printing device 100 of embodiment 1, when ink 41 is placed on the printing plate 50 using the screen 21, the ink 41 is pushed out of the opening 23 by the pressure of the squeegee 30, so that the ink 41 is easily transferred to the printing plate 50 even if the printing plate 50 has low affinity with the ink 41.

[0039] (Ink Drying Process OP2) After the printing plate creating process OP1 is completed, the ink drying process OP2 is performed. Immediately after the printing plate creating process OP1 is completed, the ink 41 on the printing plate 50 has a low viscosity. If the viscosity of the ink 41 on the printing plate 50 remains low, the ink 41 may be crushed when the printing pad 10 is pressed against the printing plate 50, resulting in an inaccurate transfer. Furthermore, bleeding of the ink 41 may reduce the accuracy of the printed image. Therefore, in the ink drying process OP2, the solvent contained in the ink 41 is evaporated to increase the viscosity of the ink 41. Note that if the viscosity of the ink 41 placed on the printing plate 50 by the ink placement device 20 is appropriate, the ink drying process OP2 can be omitted.

[0040] In the ink drying process OP2, the ink 41 on the printing plate 50 is heated by a heater 53, for example, to evaporate the solvent in the ink 41. Drying can be achieved by other means, such as blowing air, or by allowing the printing plate 50 to dry naturally for a predetermined period of time while it is placed on the printing plate stage 85. The solvent contained in the ink 41 is more volatile than the other components in the ink 41. Therefore, the viscosity of the ink is increased by evaporating the solvent from the ink 41 using means such as blowing air, thereby increasing the proportion of components other than the solvent in the ink 41. Upon completion of the ink drying process OP2, the viscosity of the ink 41 is adjusted to, for example, 3 Pa·s to 1000 Pa·s. The time required for drying the ink is preferably matched to the time required for the subsequent transfer process OP3 and pressing process OP4. This configuration allows for efficient continuous printing of a large number of printed objects 70.

[0041] Furthermore, when transitioning from the printing plate creating process OP1 to the ink drying process OP2, the printing plate 50 may be moved from the printing plate stage 85, or may remain placed on the printing plate stage 85. When the printing plate 50 is moved from the printing plate stage 85, another printing plate 50 can be immediately placed on the printing plate stage 85 and the printing plate creating process OP1 can be started, which has the advantage of shortening the cycle time of the entire offset printing process.

[0042] When drying the ink 41 on the printing plate 50 by blowing air, for example, a blower and heater may be installed next to the ink placement device 20, and the blower may blow air that has passed through the heater onto the printing plate 50. The heater installed together with the blower is preferably set so that the temperature of the blown air is as high as possible but below the boiling point of the solvent contained in the ink 41. The solvent contained in the ink 41 is selected to be one that semi-dries in the ink drying step OP2. For example, the solvent is selected to have a flash point of 40°C or higher and a boiling point of 120°C or higher. In this case, the heater temperature is set to, for example, 100°C. Note that a solvent with high dissolving power is desirable because a solvent with low dissolving power may damage the ink placement device 20. However, the ink 41 used in the printing device 100 is not limited to the above.

[0043] (Transfer process OP3) In the transfer process OP3, when printing is performed using a printing pad 10 whose surface has a curved surface such as a parabolic shape, the printing pad 10 is pressed against the printing plate 50 from the vertex, thereby transferring the printing image formed by the ink 41 on the printing plate 50.

[0044] (Pressing Step OP4) In the pressing step OP4, the printing pad 10 is pressed against the print object 70. The ink 41 adhering to the surface of the printing pad 10 is transferred to the surface of the print object 70. When printing is performed using the printing pad 10, printing can be performed by following the shape of the print object 70 even if the surface has a curved surface. Note that the print object 70 is positioned before the pressing step OP4 is performed. The positioning of the print object 70 may be performed using a jig or tool. When the pressing step is performed multiple times on the print object 70, the jig may be changed each time the pressing step is performed to change the posture of the print object 70 so that the printing pad 10 is pressed against the print surface 70a at the desired position and angle. Alternatively, when the printing pad 10 is moved by a robot arm, the angle at which the printing pad 10 is pressed against the print surface 70a can be changed, so there is no need to change the jig supporting the print object 70.

[0045] (Fixing step OP5) In the fixing step OP5, the ink 41 transferred onto the surface of the printed matter 70 in the pressing step OP4 is fixed. If UV ink is used as the ink 41, the surface of the printed matter 70 may be irradiated with ultraviolet rays using an ultraviolet irradiation device (not shown) to harden the ink 41. Alternatively, an electron beam may be irradiated instead of ultraviolet rays. If the shape of the printed matter 70 has a curved surface, it is desirable to use an ultraviolet irradiation device 80 that can irradiate ultraviolet rays along the curved surface.

[0046] Furthermore, in the fixing step OP5, the method is not limited to curing the ink 41 by irradiation with ultraviolet light or an electron beam, and may be, for example, curing the ink 41 by heating with a heater or by drying with air blowing. Alternatively, the ink 41 may be cured by natural drying.

[0047] <Operation of Printing Device 100> Fig. 8 is a flow chart showing the operation of the printing device 100 according to embodiment 1. When carrying out the method for producing a printed matter shown in Fig. 7 above, the printing device 100 operates according to the flow chart shown in Fig. 8.

[0048] (Initiation Process) The initiation process is performed immediately after starting the printing device 100. Because the surface of the printing pad 10 may not be activated immediately after starting the production of printed materials, a process is performed to properly activate the printing surface 4 of the printing pad 10. First, when the printing device 100 is started, the printing device 100 moves the printing pad 10 above the activation device 61 and lowers it toward the activation device 61. The printing pad 10 is raised after the printing surface 4 is pressed against the absorption unit of the activation device 61 and a predetermined area including the printing surface 4 comes into contact with the absorption unit. This process is referred to as the activation process (SP1). This allows liquid such as water or solvent that has soaked into the absorption unit of the activation device 61 to adhere to or soak into the printing surface 4 of the printing pad 10. The printing pad 10 has an uneven surface, which makes it easier for liquid that has soaked into the absorption unit to adhere to or soak into the printing surface 4. This process is sometimes referred to as the first initiation process.

[0049] After the first start step is completed, it is determined whether the amount of liquid adhering to the printing surface 4 of the printing pad 10 is appropriate (SP2). If the amount of liquid adhering to the printing surface 4 is not appropriate (NO in SP2), the printing device 100 performs an air blowing step (SP3). In the air blowing step, the air blowing device 62 blows air onto the printing surface 4 of the printing pad 10 to remove excess liquid adhering to the printing surface 4. Note that an inappropriate amount of liquid adhering to the printing surface 4 refers to an excessive amount of liquid adhering to the printing surface 4. The air blowing step described above is sometimes referred to as the second start step.

[0050] After completing the second start step, it is determined whether the amount of liquid adhering to the printing surface 4 of the printing pad 10 is appropriate (SP4). If excess water or solvent is still adhering to the printing surface 4 of the printing pad 10 (NO in SP4), the printing device 100 performs an absorption step (SP5). In the absorption step, the printing device 100 presses the printing surface 4 of the printing pad 10 against the cleaning device 60. This removes excess liquid adhering to the printing surface 4 of the printing pad 10. The above cleaning step is sometimes referred to as the third start step.

[0051] If an appropriate amount of water or solvent is adhered to or soaked into the printing pad 10, one or both of the air blowing step (SP3) and the absorbing step (SP5) may be omitted. The order of the air blowing step and the absorbing step may be changed. Furthermore, the air blowing step (SP3) and the absorbing step (SP5) of the starting step may be performed multiple times.

[0052] Furthermore, the steps (SP2 and SP4) of determining whether the amount of liquid adhering to the printing surface 4 of the printing pad 10 is appropriate may be performed by a sensor or by visual inspection by an operator. If the operator determines whether the amount of liquid adhering to the printing surface 4 of the printing pad 10 is appropriate, the operator operates an operation panel (not shown) or the like to decide whether to proceed to the next step or to repeat the previous step.

[0053] (Repeating Process) Once the initiation process is complete and the printing surface 4 of the printing pad 10 has been properly activated, the process moves to the repeating process. The repeating process includes an ink deposition process (S1), an ink transfer process (S2), a drying process (S3), a pressing process (S4), a cleaning process (S5), an activation process (S6), an air blowing process (S8), and an absorbing process (S10). As shown in FIG. 8 , the printing device 100 performs the ink deposition process (S1), the ink transfer process (S2), the drying process (S3), the pressing process (S4), the cleaning process (S5), the activation process (S6), the air blowing process (S8), and the absorbing process (S10) in this order. However, the repeating process is not limited to this order. For example, after the ink deposition process (S1) and the ink transfer process (S2) are completed, the printing device 100 performs the drying process (S3) through the absorbing process (S9). On the other hand, the printing apparatus 100 may perform the next ink depositing step (S1) in parallel while the drying step (S3) through the absorbing step (S9) are being performed.

[0054] The ink placement step (S1) corresponds to the printing plate creation step OP1 in the method for producing a printed material shown in FIG. 7 . The ink transfer step (S2) corresponds to the transfer step OP3 in the method for producing a printed material shown in FIG. 7 . Before the pressing step (S4), a drying step (S3) may be performed in which air is blown onto the printing surface 4 of the printing pad 10 to increase the viscosity of the ink 41 on the printing surface 4. The drying step (S3) may or may not be performed depending on the viscosity of the ink 41 on the printing plate 50. The pressing step (S4) corresponds to the pressing step OP4 in the method for producing a printed material shown in FIG. 7 . Note that the printing device 100 according to the first embodiment includes a step of moving the printing pad 10 above the printing material 70 between the ink transfer step (S2) and the pressing step (S4). The process including the ink transfer step (S2), the step of moving the printing pad 10 above the printing material 70, and the pressing step (S4) may be referred to as the printing process.

[0055] In the repeating process, one printing image area is completed each time the pressing step (S4) is performed. For example, in the case of the printed matter 70 shown in Fig. 1, the repeating process may be performed multiple times while changing the position of the printing pad 10, and an ink layer may be formed over the entire top surface of the automobile by performing the pressing step (S4) multiple times.

[0056] (Cleaning Step) In the cleaning step (S5), the printing surface 4 of the printing pad 10 after the ink 41 has been transferred to the printing surface is pressed against a flat cleaning surface of the cleaning device 60. The ink 41 remaining on the printing pad 10 is adhered to the cleaning surface. The cleaning surface is made of paper or adhesive tape, but is not limited to these.

[0057] (Activation Process, Air Blowing Process, Absorption Process) The activation process (S6) is the same as the activation process (SP1) in the start process. The air blowing process (S8) is the same as the air blowing process (SP3) in the start process. The absorption process (S10) is the same as the absorption process (SP5) in the start process. The air blowing process (S8) and the absorption process (S10) are performed depending on the amount of liquid, such as water or solvent, adhering to the printing surface 4 of the printing pad 10. One of the processes may be omitted, or at least one of the processes may be performed multiple times. The air blowing process (S8) and the absorption process (S10) are performed before each process, after the condition of the printing surface 4 of the printing pad 10 is confirmed, depending on the activation state of the printing surface 4. The condition of the printing surface 4 of the printing pad 10 is confirmed in the confirmation processes (S7 and S9), and if the activation state of the printing surface 4 is appropriate, a determination is made in the repetition determination process (S11) as to whether to perform printing again. If printing is to be performed again (YES in S11), the steps from the ink deposition step (S1) are repeated. If printing is not to be repeated (NO in S11), the production of the printed matter is terminated.

[0058] As described above, the printing device 100 performs the start-up process at startup and then repeats the process to print on a large number of print objects 70. Note that if the printing pad 10 is in an activated state, the above start-up processes (SP1 to SP5) may be omitted.

[0059] (Details of Ink Placement Step S1) Fig. 9 is a detailed flow diagram of the operation of the ink placement step (S1) according to the first embodiment. As shown in Fig. 5, the ink placement step (S1) first involves a step of pouring ink 40 onto the screen 21 (A1). In this step, the ink 40 may be poured so that it is spread over the screen 21. Alternatively, the ink 40 may be placed on a portion of the screen 21. When the ink 40 is placed on a portion of the screen 21, the ink 40 is positioned so that it spreads over the openings 23 of the screen 21 in accordance with the movement of the squeegee 30, and the openings 23 can be filled with the ink 40.

[0060] Next, the squeegee 30 moves while sliding along the surface of the screen 21 (A2). As the squeegee 30 moves while sliding along the surface of the screen 21, it spreads the ink 40 over the screen 21, and at this time the ink 40 fills the openings 23. Note that the ink filling step (A2) can be omitted if the openings 23 are already filled with ink 40. The ink filling step (A2) is performed by the squeegee 30, but it may also be performed using a dedicated filling squeegee.

[0061] Next, the screen 21 into which the ink 40 has been poured is placed above the printing blank 50 (A3). The screen 21 and the printing blank 50 are placed with a gap of, for example, about 1 mm between them. The screen 21 is placed at a predetermined position relative to the printing blank 50. The screen 21 may be positioned by abutting the screen frame 22 against a jig or the like, or may be positioned by a mechanism that can move the screen 21 or the printing blank 50 to predetermined positions relative to each other. In the step of placing the screen 21 above the printing blank 50, the screen 21 or the printing blank 50 is moved.

[0062] For example, the printing plate 50 is configured to alternately move between a position when the ink deposition step (S1) is performed and a position when the transfer step (S2) is performed. In this case, the printing plate 50 may be moved by a slide mechanism or the like that places the printing plate 50 at a predetermined position in each of the ink deposition step (S1) and the transfer step (S2). Alternatively, the screen 21 may be moved by a slide mechanism or the like. For example, when the printing plate 50 is fixed and when the surface of the printing plate stage 85 serves as the printing plate 50, the screen 21 is moved.

[0063] Next, the squeegee 30 moves while sliding along the surface of the screen 21, and the screen 21 is pressed against the printing plate 50, thereby transferring the ink 40 filled in the openings 23 to the printing plate 50 (A4). At this time, the squeegee 30 slides along the surface of the screen 21 while being subjected to a predetermined load directed toward the screen 21. As a result, the screen 21 is pressed against the printing plate 50 by the squeegee 30. The portions of the screen 21 that are pressed against the squeegee 30 come into close contact with the surface of the printing plate 50. The ink 41 filled in the openings 23 comes into contact with the surface of the printing plate 50 and adheres to the surface of the printing plate 50 as it is pressed against the printing plate 50 together with the screen 21 by the squeegee 30. In FIG. 5, one squeegee 30 is used to fill the openings 23 with ink 40 (A2) and transfer the ink from the screen 21 to the printing plate 50 (A4), but the squeegee 30 may be made up of two squeegees: one for filling and one for transferring.

[0064] After the squeegee 30 has moved while sliding over a predetermined area of ​​the screen 21, the screen 21 is separated from the printing plate 50 (A5). This step may be achieved by moving the screen 21 or the printing plate 50. For example, the screen 21 and the printing plate 50 are separated by moving the printing plate 50 to a position where the transfer step (S2) is performed.

[0065] 8 is performed multiple times, the step (A1) of applying ink 40 onto the screen 21 may be omitted. In other words, if a sufficient amount of ink 40 applied previously remains on the screen 21, that ink 40 may be used to place ink 41 on the printing plate 50. In addition, the step (A3) of placing the screen 21 above the printing plate 50 may be performed before applying ink (A1) or filling the openings 23 with ink (A2).

[0066] (Modification of Printing Pad 10) Figure 10 shows a modification of the printing pad 10 used in the printing device 100 of embodiment 1. The printing pad 10 according to embodiment 1 may include a protective coating layer 3 covering the surface of the substrate 5. The protective coating layer 3 constitutes the outer printing surface 4 of the printing pad 10. The protective coating layer 3 is formed, for example, by attaching a 0.5 mm silicone rubber sheet to the surface of the outer layer 2. The protective coating layer 3 also serves to prevent silicone oil contained in the soft silicone rubber inside from seeping out onto the printing surface 4. Furthermore, the outer surface of the protective coating layer 3 constitutes the printing surface 4 and is repeatedly pressed against the printing plate 50 and the surface to be printed, so it must be durable against scratches and abrasion. Therefore, the protective coating layer 3 uses a material that is harder than the outer layer 2 and is thin enough to conform to the printing surface when the printing surface 4 is pressed against the surface to be printed.

[0067] In the first embodiment, the thickness of the protective coating layer 3 is configured to be as thin as possible, for example, in the range of 0.1 mm to 1 mm. The material of the protective coating layer 3 is not limited to silicone rubber, and any material can be selected as appropriate as long as it follows the deformation of the inner layer 1 and the outer layer 2. Furthermore, it is desirable that the protective coating layer 3 has sufficient elasticity so that it can be attached to the surface of the substrate 5 in the process of attaching the protective coating layer 3 to the substrate 5. The printing pad 10 may be further formed into a multi-layer structure. For example, the inner layer 1 or the outer layer 2 of the printing pad 10 shown in FIG. 10 may be further formed into a multi-layer structure using materials with different hardnesses.

[0068] The protective coating layer 3 is attached to the surface of the substrate 5 (the surface of the outer layer 2). However, if it is damaged, such as scratched or worn, it can be peeled off from the surface of the substrate 5 and replaced with a new one. The protective coating layer 3 is less expensive than the substrate 5, and replacement allows the internal substrate 5 to be used as is. Therefore, by updating the protective coating layer 3, the expensive substrate 5 can be reused repeatedly, and the printing surface 4 of the printing pad 10 can be maintained in a state suitable for printing. Ultimately, the printing device 100 according to the first embodiment can reduce printing costs. Furthermore, the outer layer 2 constituting the substrate 5 is softer than the inner layer 1. Therefore, it can conform well to the shape of the printed object 70. If the outer layer 2 is damaged by a high load applied through the protective coating layer 3, the surface may harden by repeatedly updating (replacing) the protective coating layer 3 as described above. In such cases, the outer layer 2 can be replaced. Replacing the outer layer 2 allows the inner layer 1 to be used for a long period of time. 3 and 10, the substrate 5 is composed of the internal layer 1 and the external layer 2, but it may be composed of only one layer, the internal layer 1. In other words, the protective coating layer 3 may be provided on the substrate 5 formed of only one layer, the internal layer 1. However, there are cases where the substrate 5 is damaged by the work of peeling off the protective coating layer 3 when replacing the protective coating layer 3 attached to the substrate 5, where deep scratches are made from the printing surface 4 of the printing pad 10, or where deterioration such as hardening of the surface of the substrate 5 occurs. For this reason, it is desirable that the substrate 5 be composed of multiple layers as shown in FIGS. 3 and 10.

[0069] (Regarding printing surface 4 of printing pad 10) It is preferable that printing surface 4, which is the surface of printing pad 10 and is pressed against printing plate 50, has minute irregularities formed on the surface according to the thickness of the ink 41 to be printed. In the printing device 100 according to embodiment 1, by using screen 21 to place ink 41 on printing plate 50, the ink 41 placed on printing plate 50 can be made thick. By forming irregularities on printing surface 4 according to the thickness of ink 41 on printing plate 50, the ink 41 transferred to printing pad 10 can also be made thicker than before.

[0070] When transferring a relatively thick ink 41 to the printing surface 4 of the printing pad 10, it is preferable to form an uneven surface on the printing pad 10. The uneven shape can be formed, for example, by transferring the uneven shape of a mold surface during molding of the printing pad 10. Alternatively, in the printing pad 10 shown in FIG. 10, the uneven shape can be formed on the surface when molding the protective coating layer 3 to be attached to the surface of the substrate 5. In the case of the printing pad 10 shown in FIG. 10, the uneven shape is formed on the protective coating layer 3, which is a sheet-like member, so the desired uneven shape can be easily obtained. Furthermore, by replacing the protective coating layer 3, it is easy to change the height difference from the highest to lowest points of the uneven shape 14, the detailed shape of the unevenness, or the hardness of the protective coating layer 3. In particular, in the case of a printing pad 10 used for printing automotive-related parts, since the substrate 5 is large, being able to adjust the height difference and the like by changing only the surface protective coating layer 3 is advantageous in terms of cost and production time.

[0071] If the height difference between the highest and lowest points of the uneven surface of the protective coating layer 3 after molding is a desired value, it may be attached to the substrate 5 as is. However, if the height difference d (see FIG. 11 ) between the highest and lowest points of the uneven surface is greater than the desired value, the surface of the sheet constituting the protective coating layer 3 may be rubbed with an abrasive material such as abrasive cloth or paper to remove the protruding portions 4 a (see FIG. 11 ) of the uneven surface, i.e., the high portions. Alternatively, an abrasive sponge such as a melamine sponge may be used. In other words, the surface of the sheet forming the protective coating layer 3 may be molded in a rough state and then polished or otherwise adjusted to conditions that facilitate transfer to the printing surface 4. Note that the above description is for a printing pad 10 having a protective coating layer 3. However, in a printing pad without a protective coating layer 3, such as the printing pad 10 shown in FIG. 3, the surface of the substrate 5 may be roughly molded in advance and the uneven surface shape may be gradually adjusted by polishing or the like.

[0072] The height difference between the highest and lowest parts of the uneven shape 14 is set according to the thickness of the ink 41 placed on the printing plate 50. Since the thickness of the ink 41 placed on the printing plate 50 is adjusted according to the thickness h of the screen 21 shown in Figure 6, the height difference d of the uneven shape 14 on the printing surface 4 of the printing pad 10 is set according to the thickness h of the screen 21.

[0073] For example, when painting an automobile, the thickness of the paint layer formed by one coating is 10 μm to 20 μm. In other words, when the printing device 100 of embodiment 1 is used for painting an automobile, the thickness of the ink 41 applied to the loading surface of the printing plate 50 in the ink loading step (S1) should be set to 10 μm to 20 μm. Therefore, the height difference from the highest to lowest point of the uneven shape 14 on the printing surface 4 of the printing pad 10 should also be set to 10 μm to 20 μm. However, if it is difficult to form an ink layer of 10 μm to 20 μm on the printing surface 70a in a single printing run, it is recommended to perform printing in multiple runs.

[0074] The thickness of the ink layer on the printing plate 50 (the thickness of the ink 41 in FIGS. 5 and 6) is approximately the same as the thickness of the screen 21. The value of the difference in height from the highest to the lowest point of the uneven shape of the printing surface 4 is set to be slightly smaller than the thickness h of the screen 21 to make it easier to transfer the ink. In other words, the thickness h of the screen 21 is set to be larger than the difference in height of the uneven shape of the printing surface 4 of the printing pad 10.

[0075] The height difference between the highest and lowest points of the uneven shape of the printing surface 4 is the maximum height roughness Rz or the three-dimensional surface roughness S Ｚ The surface roughness Rz and S of the printing surface 4 Ｚ is measured by a non-contact type roughness meter. The height difference between the highest and lowest points of the uneven shape is the surface roughness R Ｚ and S Ｚ It may be set based on the

[0076] Fig. 11 is an enlarged schematic diagram of the printing surface 4 of the printing pad 10 according to the first embodiment. The uneven shape formed on the printing surface 4 is crushed when the printing surface 4 is pressed against the printing plate 50, and is deformed in a direction that reduces the height difference d. Therefore, it is preferable that the uneven shape is set so that the height difference d, which is the dimension from the apex of the protrusion 4a to the valley 4b, is larger than the width between the apexes of the protrusions 4a. Note that although Fig. 11 shows a substantially uniform uneven shape on the printing surface 4, in reality, there is variation in the positions of the apexes of the protrusions 4a and the bottoms of the valleys 4b. Therefore, in reality, the surface roughness R Ｚ and S Ｚ The surface roughness R Ｚ and S Ｚ It is recommended to set the value to be large.

[0077] If the surface is rough, printing with the printing pad 10 may result in a rough product surface (ink layer surface), especially in solid printing. In this case, the ink viscosity can be set low, for example, to 10 Pa·s (100 poise) or less to make the surface smooth. However, the ink viscosity is not limited to the above.

[0078] Although the present invention has been described above based on the embodiments, the present invention is not limited to the configurations according to the above-described embodiments. In particular, the combination of components is not limited to the combinations in the embodiments, but can be modified as appropriate. Furthermore, it should be noted that the gist (technical scope) of the present invention also includes various modifications, applications, and uses that may be made by those skilled in the art as needed.

[0079] REFERENCE SIGNS LIST 1 Inner layer, 2 Outer layer, 3 Protective coating layer, 4 Printing surface, 4a Protrusion, 4b Valley, 5 Substrate, 6 Top, 7 Support member, 10 Printing pad, 11 Vertical movement device, 12 Horizontal movement device, 13 Plane, 14 Concave and convex shape, 15 Height difference, 20 Ink placement device, 21 Screen, 22 Screen frame, 23 Opening, 24 Mesh member, 24a Fiber, 24b Fiber, 24c Gap, 25 Emulsion, 30 Squeegee, 40 Ink, 41 Ink, 50 Printing plate, 51 Placement surface, 53 Heater, 60 Cleaning device, 61 Activation device, 62 Air blowing device, 66 Blower, 68 Temperature sensor, 70 Printed matter, 70a Printed surface, 74 Periphery, 75 Connection area, 75a Connection area, 75b Connection area, 80 ultraviolet irradiation device, 85 printing original plate stage, 86 surface treatment stage, 87 printing stage, 90 control device, 90a arithmetic device, 90b storage device, 100 printing device, height difference d, h thickness, interval w.

Claims

1. A printing apparatus comprising: a printing pad having a printing surface that deforms to follow the shape of the printed surface of a printed matter; a printing plate having a mounting surface on which ink is placed; and an ink mounting device that places ink on the surface of the printing plate, wherein the printing pad is configured to be freely movable between the printing plate and the printed matter and is configured to be pressed against the printing plate or the printed matter, and the ink mounting device comprises a screen having openings formed therein through which ink passes, and a squeegee that slides over the surface of the screen.

2. The printing device according to claim 1, wherein the squeegee slides over the surface of the screen on which ink is placed, forcing the ink to pass through the openings.

3. A printing device according to claim 1 or 2, wherein the screen is a woven metal fiber fabric.

4. The printing device according to claim 1 or 2, wherein the screen is a woven fabric of resin fibers.

5. A printing device as claimed in claim 1 or 2, wherein the screen has openings formed by processing a metal plate or a resin plate into holes.

6. A printing device according to any one of claims 3 to 5, wherein the screen has hardened emulsion fixed to at least a portion thereof, and the portion to which the emulsion is not fixed constitutes the opening.

7. Three-dimensional surface roughness S of the printing surface of the printing pad Ｚ The printing device according to claim 1 , wherein the value is set to be larger as the thickness of the screen increases.

8. The thickness of the screen is determined based on the three-dimensional surface roughness S of the printing surface of the printing pad. Ｚ 8. The printing device according to claim 7, wherein the value is set to be greater than the value of .

9. A printing device described in any one of claims 1 to 8, wherein the squeegee slides over the surface of the screen while pressing the screen against the printing plate, with the screen carrying ink being positioned above the printing plate with a gap therebetween.

10. A printing device according to any one of claims 1 to 9, wherein the printing plate has a surface that has been subjected to a surface treatment that reduces affinity for ink.

11. A printing apparatus according to any one of claims 1 to 10, wherein the printing plate is a part of the surface of a printing plate stage.

12. The printing apparatus according to any one of claims 1 to 11, wherein the ink placement device is installed on a printing plate stage, and the printing plate stage is configured to be movable.

13. A method for producing a printed item, in which the printing surface of a printing pad is pressed against the printed surface of a printed item to transfer ink placed on the printing surface and form an ink layer on the printed surface, comprising: an ink placing step in which, after the ink is placed on a screen, a squeegee is slid along the surface of the screen to pass the ink through openings formed in the screen, thereby placing the ink on the surface of the printing plate; a transfer step in which the printing surface is pressed against the printing plate on which the ink has been placed, to transfer the ink on the printing plate to the printing surface; and a pressing step in which the printing surface is pressed against the surface of the printed item while deforming it to conform to the surface of the printed item, thereby forming the ink layer.

Images