Printing device and printing method thereof

Abstract

The present invention provides a printing device and a printing method thereof. The printing device (10) comprises: a printing section (16) that prints a printed material (P) on a transfer sheet (12); a transfer section (17) that transfers a printed pattern to a transfer surface (W1) of a workpiece (W); a first curing section (44a, 44b) that semi-cures the printed material on the transfer sheet; and a second curing section (50) that completely cures the printed material transferred to the transfer surface of the workpiece. The receiving section (48) of the transfer section comprises a first space section (78) and a second space section (80). In the first space section, the printed material printed on the transfer sheet faces the workpiece. The pressure in the first space section is lower than the pressure in the second space section by a pressure adjustment section (54). Accordingly, the printed material can be transferred to the transfer surface with high precision, and the manufacturability can be improved by suppressing the generation of cracks in the printed material.

Description

Technical Field

[0001] The present invention relates to a printing device and a printing method thereof that ejects ink to form printed matter on a transfer sheet and transfers the printed matter to a workpiece. Background Art

[0002] The printing device disclosed in Japanese Patent Application Publication No. 2010-117621 rotates a transfer sheet via rollers on a gravure plate filled with a material. After a material pattern is placed on the transfer sheet, the material is transferred onto a substrate (the printing target) while retaining the material pattern. After transfer, the material pattern on the substrate is cured by irradiation with UV light from a UV light irradiation device. Summary of the Invention

[0003] In Japanese Patent Application Laid-Open No. 2010-117621, because the material pattern is transferred to the printing object before solidification, there is a risk that the material pattern may not be smoothly transferred from the transfer sheet to the printing object. Furthermore, when transferring a material pattern to a three-dimensional printing object using a printing device, if the material (material pattern) completely solidifies before transfer, there is a concern that cracks may occur in the material pattern.

[0004] The purpose of the present invention is to solve the above technical problems.

[0005] The technical solution of the present invention is: a printing device that ejects ink to form a printed matter on a transfer sheet, and transfers the printed matter from the transfer sheet to a transfer surface of a workpiece, characterized in that:

[0006] It has a printing unit, a transfer unit, a conveying unit, a first curing unit and a second curing unit, wherein:

[0007] The printing unit includes a nozzle member for ejecting the ink, and forms the printed matter on a first surface, which is one surface of the transfer sheet.

[0008] The transfer unit transfers the printed matter from the transfer sheet to the transfer surface of the workpiece;

[0009] The transport unit transports the printed portion of the transfer sheet on which the printed matter is printed from the printing unit to the transfer unit;

[0010] The first curing unit semi-cures the printed matter printed on the transfer sheet;

[0011] The second curing unit completely cures the printed matter transferred to the workpiece.

[0012] The transfer unit includes a receiving unit and a pressure adjustment unit, wherein:

[0013] The receiving portion has a space capable of receiving the workpiece and the printing portion, and is capable of receiving a portion of the transfer sheet in such a manner that the printed matter printed on the transfer sheet faces the workpiece, wherein the space is divided into a first space portion and a second space portion by the transfer sheet, wherein the first space portion faces the first surface of the transfer sheet, and the second space portion faces the second surface which is the other surface of the transfer sheet;

[0014] The pressure adjustment unit generates a pressure difference between the first space and the second space such that the pressure in the first space is lower than the pressure in the second space.

[0015] According to the present invention, the following effects can be obtained.

[0016] Specifically, after the printed material is printed on the first surface of the transfer sheet by the printing section and semi-cured by the first curing section, the pressure in the first space facing the first surface is lowered than the pressure in the second space, and the first surface of the transfer sheet is moved toward the workpiece. This allows the semi-cured, flexible printed material to contact the workpiece's transfer surface, effectively transferring the printed material to the transfer surface. As a result, regardless of the shape of the workpiece's transfer surface, the printed material can be transferred to the transfer surface with high precision, while suppressing the occurrence of cracks.

[0017] The above-mentioned objects, features and advantages will be easily understood through the following description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a diagram showing the overall configuration of a printing process and a first curing process of a printing device according to an embodiment of the present invention.

[0019] Figure 2 Yes Figure 1 An overhead view of the vicinity of the printing unit in a printing device.

[0020] Figure 3 This is a diagram showing the overall structure of the conveying process of the printing device.

[0021] Figure 4 This is a diagram showing the overall structure of the sealing process of the printing device.

[0022] Figure 5 This is a diagram showing the overall structure of the transfer process of the printing device.

[0023] Figure 6 It is an operation explanatory diagram showing the second curing step of the printing device.

[0024] Figure 7This is an explanatory diagram of the operation when transferring a plurality of printed materials onto a workpiece, and is an overall configuration diagram showing a first printing step in which a first printed material is printed onto a transfer sheet in a printing section.

[0025] Figure 8 This is an overall structural diagram showing a first transfer step of transferring a first printed material onto a workpiece and a second printing step of printing a second printed material in a printing section.

[0026] Figure 9 This is a diagram showing the overall configuration when the second printed material is conveyed to the transfer section.

[0027] Figure 10 This is an overall structural diagram showing a second transfer step of transferring a second printed material onto a workpiece and a third printing step of printing a third printed material in a printing section.

[0028] Figure 11 This is an overall structural diagram showing the third transfer step of transferring the third printed material onto the workpiece. DETAILED DESCRIPTION

[0029] like Figures 1 to 11 As shown, the printing device 10 includes a conveying unit 14 containing a transfer sheet 12, a printing unit 16, a transfer unit 17, and a control unit 18. The printing device 10 prints a printed object P on the transfer sheet 12 by ejecting ink from a nozzle assembly 20 of the printing unit 16. The printing device 10 transfers the printed object P from the transfer sheet 12 onto a transfer surface W1 of a workpiece W.

[0030] In this embodiment, the workpiece W is, for example, an instrument panel mounted in an automobile. A cross-section of the workpiece W perpendicular to its longitudinal direction is curved. The longitudinal direction of the workpiece W corresponds to the vehicle width when the instrument panel is mounted in the automobile. The transfer surface W1 of the workpiece W is the surface of the instrument panel exposed to the interior of the vehicle. The transfer surface W1 of the workpiece W is a three-dimensionally curved, non-flat surface.

[0031] The transport unit 14 includes the transfer sheet 12 and a rotating mechanism 24 .

[0032] The transfer sheet 12 is formed into a sheet of stretchable resin (e.g., a silicone sheet). The transfer sheet 12 is an endless ring that is elongated in the conveying direction and has no end portions. The top surface 12a of the transfer sheet 12 is the first surface on which the printed material P is printed by the printing unit 16.

[0033] The rotation mechanism 24 rotates the transfer sheet 12 to transport the printed material P printed on the transfer sheet 12 from the printing section 16 to the transfer section 17. The rotation mechanism 24 includes a drive roller 26 and first to third driven rollers 28, 30, and 32. The transfer sheet 12 is wound around the outer circumference of the drive roller 26 and the outer circumferences of the first to third driven rollers 28, 30, and 32.

[0034] The driving roller 26 is rotatably supported on a frame (not shown). The driving roller 26 is connected to a motor 34 as a driving source. The motor 34 rotates according to a control signal from the control device 18. As the motor 34 rotates, the driving roller 26 rotates in a predetermined direction. Figure 1 The following description will assume that the middle driving roller 26 rotates clockwise.

[0035] The first to third driven rollers 28, 30, and 32 are each rotatably supported on a frame (not shown). The first driven roller 28 is positioned at the same height as the drive roller 26. The first driven roller 28 is positioned a predetermined distance away from the conveyance direction (forward) of the drive roller 26. Hereinafter, the conveyance direction of the transfer sheet 12 is referred to as the front direction, and the direction opposite to this conveyance direction is referred to as the rear direction. The horizontal direction perpendicular to the conveyance direction of the transfer sheet 12, which is the direction in which the second guide rail 42 extends, is referred to as the width direction.

[0036] The second driven roller 30 is disposed below the first driven roller 28 and spaced a predetermined distance from the first driven roller 28. The third driven roller 32 is disposed below the driving roller 26 and spaced a predetermined distance from the driving roller 26.

[0037] The transfer sheet 12 is arranged so as to span the outer peripheral surfaces of the drive roller 26 and the first to third driven rollers 28, 30, and 32. The inner surface of the transfer sheet 12 is held by the outer peripheral surfaces of the drive roller 26 and the first to third driven rollers 28, 30, and 32. The transfer sheet 12 is held in a tensioned state.

[0038] The upper portion of the transfer sheet 12 (hereinafter referred to as the first circulation portion 36a) is held in the horizontal direction by the driving roller 26 and the first driven roller 28. The upper surface 12a of the first circulation portion 36a is the surface facing the printing unit 16.

[0039] The side portion of the transfer sheet 12 (hereinafter referred to as the second circulation portion 36b) is held by the drive roller 26 and the third driven roller 32. The second circulation portion 36b is arranged in front of the first circulation portion 36a. The second circulation portion 36b is a portion of the transfer sheet 12 that is continuous with the first circulation portion 36a. The second circulation portion 36b extends in the vertical direction.

[0040] The lower portion of the transfer sheet 12 (hereinafter referred to as the third loop portion 36c) is held by the second driven roller 30 and the third driven roller. The third loop portion 36c is arranged below the first loop portion 36a. The third loop portion 36c is arranged behind the second loop portion 36b. The third loop portion 36c is a portion of the transfer sheet 12 that is continuous with the second loop portion 36b. The third loop portion 36c extends horizontally (front-to-back).

[0041] A side portion of the transfer sheet 12 (hereinafter referred to as the fourth loop portion 36d) is held by the drive roller 26 and the third driven roller 32. The fourth loop portion 36d is located behind the first loop portion 36a and the third loop portion 36c. The fourth loop portion 36d is a portion of the transfer sheet 12 that is continuous with the third loop portion 36c. The fourth loop portion 36d extends in the vertical direction.

[0042] That is, the transfer sheet 12 is an endless belt (endless belt) formed by continuously connecting the first to fourth circulation sections 36a, 36b, 36c, and 36d. When viewed from a direction perpendicular to the conveying direction of the transfer sheet 12, the transfer sheet 12 is a substantially rectangular shape that is long in the front-to-back direction.

[0043] When the motor 34 rotates in response to a control signal from the control device 18, causing the drive roller 26 to rotate clockwise, the transfer sheet 12 is fed to the right of the paper surface (in the conveyance direction). The transfer sheet 12 is rotated clockwise by the drive roller 26 and the first to third driven rollers 28, 30, and 32. As the transfer sheet 12 rotates, the first to third driven rollers 28, 30, and 32, which are in contact with the inner surface of the transfer sheet 12, also rotate clockwise.

[0044] The printing unit 16 is located above the transfer sheet 12 (first circulation unit 36a). The printing unit 16 is located a predetermined distance above the transfer sheet 12. In the front-to-back direction of the printing device 10, the printing unit 16 is located slightly behind the drive roller 26.

[0045] The printing unit 16 includes a nozzle assembly 20, a first guide rail 40, a second guide rail 42, and a pair of first curing sections 44a and 44b. The nozzle assembly 20 is arranged approximately parallel to the transfer sheet 12. The nozzle assembly 20 is not particularly limited, and an inkjet head can be used as an example. The nozzle assembly 20 is capable of ejecting ink from a nozzle (not shown). The nozzle is arranged on the lower surface of the nozzle assembly 20. Ink is supplied to the nozzle assembly 20 from an ink supply source (not shown). Ink is ejected vertically downward from the nozzle of the nozzle assembly 20. The ink is applied to the upper surface 12a of the transfer sheet 12 arranged below the nozzle assembly 20.

[0046] In this embodiment, the ink is UV-curable ink (active energy ray-curable ink), that is, ink that can be cured by irradiating UV rays (Ultra Violet: ultraviolet rays, active energy rays) after the ink is ejected to print a pattern.

[0047] The nozzle assembly 20 is arranged so as to be movable along the first guide rail 40 and the second guide rail 42. The first guide rail 40 and the second guide rail 42 are arranged above the nozzle assembly 20. The first guide rail 40 extends along the conveying direction (forward and backward) of the transfer sheet 12 conveyed by the conveying unit 14. The second guide rail 42 extends in the width direction perpendicular to the conveying direction of the transfer sheet 12 (see FIG. Figure 2 The first guide rail 40 and the second guide rail 42 extend in the horizontal direction respectively.

[0048] The nozzle assembly 20 is held on the first guide rail 40. The nozzle assembly 20 can be moved forward and backward along the first guide rail 40 by the driving force of a driving device (not shown). The nozzle assembly 20 is held on the second guide rail 42 via the first guide rail 40. The nozzle assembly 20 can be moved in the width direction along the second guide rail 42 by the driving force of a driving device (not shown). In other words, the nozzle assembly 20 can be moved two-dimensionally along a horizontal plane by the first guide rail 40 and the second guide rail 42. The nozzle assembly 20 can move parallel to the transfer sheet 12.

[0049] The nozzle assembly 20 is driven and controlled based on a control signal from the control device 18. The ejection of ink from the nozzle assembly 20 is controlled based on the control signal from the control device 18. Ink is ejected downward from the nozzle assembly 20, which moves horizontally in the front-back and width directions along the first and second guide rails 40 and 42. Ink is thereby applied to the upper surface 12a of the transfer sheet 12, and a printed object P is printed in a predetermined printing pattern.

[0050] A pair of first curing sections 44a and 44b are mounted at the front and rear ends of the nozzle assembly 20. The first curing sections 44a and 44b are positioned at approximately the same height as the nozzle assembly 20. The first curing sections 44a and 44b each include a first irradiation device 46 capable of irradiating UV rays. The first irradiation devices 46 are positioned on the lower surfaces of the first curing sections 44a and 44b, respectively, facing the conveyor section 14. The first irradiation devices 46 are capable of irradiating first irradiation light L1, which is UV rays, downward from an irradiation portion (not shown), in response to a control signal from the control device 18.

[0051] In response to a control signal from the control device 18, the first irradiation device 46 irradiates the printed material P printed on the upper surface 12a of the transfer sheet 12 with the first irradiation light L1. Consequently, the printed material P, printed with UV-curable ink, is cured by the first irradiation light L1. When the first irradiation device 46 irradiates the printed material P with the first irradiation light L1, the first irradiation intensity of the first irradiation light L1 is controlled to an intensity that does not completely cure the printed material P. In other words, the first curing units 44a and 44b partially cure (incompletely cure) the printed material P.

[0052] Furthermore, a pair of first curing units 44a and 44b may be disposed at both ends in the width direction of the nozzle assembly 20. Alternatively, a single first curing unit may be disposed on the nozzle assembly 20. The first curing unit is not limited to a device that irradiates UV rays, but may also be a heater or an air blower for semi-curing the printed matter P on the transfer sheet 12.

[0053] The transfer unit 17 is arranged forwardly away from the printing unit 16. In the front-rear direction of the printing device 10, the transfer unit 17 is arranged slightly forwardly of the first driven roller 28. The transfer unit 17 and the printing unit 16 are separated by a predetermined distance in the front-rear direction.

[0054] The transfer unit 17 includes a storage unit 48 , a second curing unit 50 , a lifting mechanism 52 , and a pressure adjustment unit 54 .

[0055] The storage section 48 has a space 56 capable of storing the printed matter P and the workpiece W printed on the transfer sheet 12 , and is configured to be able to seal the space 56 . The storage section 48 can store a portion of the transfer sheet 12 .

[0056] The storage portion 48 includes a base 58 and a box 60 .

[0057] The base 58 is placed on a floor (not shown). The base 58 is positioned below the first circulation section 36a of the transfer sheet 12. When the transfer section 17 is viewed from above, the base 58 has a rectangular shape. The upper portion of the base 58 forms a cover 62. The cover 62 faces the lower surface 12b of the transfer sheet 12. The lower surface 12b of the transfer sheet 12 is the surface opposite to the upper surface 12a on which the printed matter P is printed. The outer edge of the cover 62 includes a first sealing portion 64.

[0058] The first sealing portion 64 protrudes upward from the outer edge of the cover portion 62. The first sealing portion 64 is arranged in a ring shape along the entire circumference of the outer edge. The upper end of the first sealing portion 64 faces the lower surface 12b of the transfer sheet 12 (first circulation portion 36a). The first sealing portion 64 is formed of an elastic material such as rubber.

[0059] The housing 60 is positioned above the first circulation section 36a of the transfer sheet 12. The housing 60 faces the top of the base 58, with the transfer sheet 12 interposed therebetween. The housing 60 and the base 58 (cover 62) of the transfer section 17 are positioned one above the other, sandwiching the transfer sheet 12. The transfer sheet 12 is positioned between the lower end of the housing 60 and the upper end of the base 58.

[0060] The housing 60 is a bottomed body with an open bottom end. When the transfer unit 17 is viewed from above, the housing 60 is rectangular corresponding to the base 58. The housing 60 can be moved vertically orthogonal to the conveyance direction of the transfer sheet 12 by the lifting mechanism 52.

[0061] The lower end of the housing 60 includes a second sealing portion 66. The second sealing portion 66 is arranged in an annular shape along the entire circumference of the lower end of the housing 60. The second sealing portion 66 is formed of an elastic material such as rubber. The second sealing portion 66 faces the upper surface 12a of the transfer sheet 12. The lower end of the housing 60 can be sealed by a lid 62.

[0062] The upper portion of the housing 60 includes a top portion 68. The top portion 68 is spaced a predetermined distance upward from the lower end of the housing 60. The top portion 68 is substantially parallel to the transfer sheet 12 and is flat. The top portion 68 includes a support 70 and a communication hole 72.

[0063] The support body 70 is capable of holding the workpiece W. The support body 70 extends vertically downward from the inner surface of the top 68. The support body 70 is arranged in the center of the top 68. The support body 70 is arranged inside the box body 60. The lower end of the support body 70 has a support piece 74. The support surface of the support piece 74 is capable of holding the workpiece W. The support surface is a surface facing downward. The support surface is a curved surface corresponding to the cross-sectional shape of the workpiece W. Through a fixing mechanism not shown in the figure, the inner surface of the workpiece W abuts against the support surface of the support piece 74, so that the workpiece W is fixed. When the workpiece W is fixed to the support body 70, the transfer surface W1, which is the surface of the workpiece W, faces downward.

[0064] A plurality of communication holes 72 are provided in the top portion 68. The communication holes 72 extend vertically through the top portion 68. The communication holes 72 connect the interior and exterior of the housing 60. The communication holes 72 communicate with the pressure regulating portion 54. The communication holes 72 can be provided on the side of the housing 60 or on the cover portion 62 of the base 58.

[0065] The second curing unit 50 is disposed on the upper surface of the cover 62. The second curing unit 50 is exposed upward in the cover 62. The second curing unit 50 includes a second irradiation device 51. The second irradiation device 51 can irradiate second irradiation light L2, which is UV radiation. The second irradiation device 51 is disposed so as to face the housing 60.

[0066] The second irradiation device 51 irradiates the transfer surface W1 of the workpiece W to which the printed matter P is transferred with the second irradiation light L2 (see FIG. 1 ). Figure 6 ).

[0067] In this manner, UV rays are used to cure the ink, and the printed material P is cured on the transfer surface W1. When the second irradiation device 51 irradiates the transfer surface W1 (printed material P) of the workpiece W with the second irradiation light L2, the second irradiation light L2 is irradiated at an irradiation intensity sufficient to completely cure the printed material P. The second irradiation device 51 may also be arranged within the housing 60 so as to irradiate the transfer surface W1 of the workpiece W with the second irradiation light L2. The second curing unit 50 is not limited to a device that irradiates UV rays; it may also be a heater or blower for drying and completely curing the printed material P. In this case, the heater or blower is arranged within the housing 60.

[0068] The lifting mechanism 52 is provided so as to be able to raise or lower the housing 60. The lifting mechanism 52 includes a lifting arm 76 connected to the top 68 of the housing 60. The lifting mechanism 52 is driven by a control signal from the control device 18.

[0069] When the lifting mechanism 52 is driven to raise the lifting arm 76, the box body 60 is lifted and raised together with the lifting arm 76. As a result, the first sealing portion 64 of the box body 60 and the second sealing portion 66 of the cover 62 are separated in the vertical direction (see FIG. Figure 1 ). When the lifting mechanism 52 is driven to lower the lifting arm 76, the box body 60 is lowered together with the lifting arm 76. Accordingly, the first sealing portion 64 of the box body 60 abuts against the second sealing portion 66 of the cover 62 (refer to Figure 4 ). As the first sealing portion 64 and the second sealing portion 66 abut, a space 56 surrounded by the box body 60 and the cover 62 is formed inside the box body 60. The space 56 is a space sealed by the cover 62 of the base 58 and the box body 60 (refer to Figure 4 ).

[0070] The space 56 has two space portions divided in the vertical direction by the transfer sheet 12, namely, a first space portion 78 and a second space portion 80 (see Figure 4 and Figure 5 The first space 78 is a space enclosed by the housing 60 and the upper surface 12a of the transfer sheet 12. The second space 80 is a space enclosed by the cover 62 of the base 58 and the lower surface 12b of the transfer sheet 12. Specifically, within the space 56 of the storage section 48, the first space 78 is located above the transfer sheet 12. The second space 80 is located below the transfer sheet 12.

[0071] The pressure regulating portion 54 is disposed above the top portion 68 of the housing 60. Figure 4 and Figure 5When the box body 60 and the cover 62 shown are sealed (sealing process), the pressure regulating unit 54 generates a pressure difference between the pressure of the first space 78 and the pressure of the second space 80. The pressure regulating unit 54 has a negative pressure supply source for supplying negative pressure. The pressure regulating unit 54 can supply negative pressure to the interior of the box body 60 through the connecting hole 72 provided in the top 68. In addition, the pressure regulating unit 54 can be provided on the base 58, or it can supply positive pressure to the second space 80 through the connecting hole 72 provided in the cover 62. It is also possible to generate a pressure difference between the pressure of the first space 78 and the pressure of the second space 80 by providing the pressure regulating unit 54 on the box body 60 and the base 58.

[0072] When the housing 48 is sealed by the sealed case 60 and the lid 62, negative pressure is supplied from the pressure regulating unit 54 through the communicating hole 72 to the first space 78 of the housing 48 in response to a control signal from the control device 18. Since the second space 80 is at atmospheric pressure, when negative pressure is supplied to the first space 78, the pressure in the first space 78 becomes lower than the pressure in the second space 80.

[0073] The control device 18 is electrically connected to the conveying unit 14 , the printing unit 16 , and the transfer unit 17 , respectively, and controls the conveying unit 14 , the printing unit 16 , and the transfer unit 17 .

[0074] The control device 18 outputs a control signal to the rotation mechanism 24 of the conveying unit 14. The control device 18 controls the motor 34 of the drive roller 26 to rotate the drive roller 26 clockwise. By driving and controlling the motor 34, the control device 18 feeds the transfer sheet 12 forward and conveys the printed material P to a predetermined position.

[0075] The control device 18 outputs a control signal to the printing unit 16. The control device 18 controls the nozzle assembly 20 to move along the first guide rail 40 and the second guide rail 42. When the printing unit 16 prints the printed object P on the transfer sheet 12, the control device 18 controls the first curing units 44a and 44b to irradiate the printed object P with the first irradiation light L1.

[0076] The control device 18 outputs a control signal to the transfer unit 17. The control device 18 controls the lifting mechanism 52 to raise or lower the housing 60 of the storage unit 48. The control device 18 controls the pressure adjustment unit 54 to supply negative pressure fluid to the first space 78 of the storage unit 48. The control device 18 controls the second curing unit 50 to irradiate the second irradiation light L2 onto the printing unit 16 transferred to the transfer surface W1 of the workpiece W.

[0077] Next, the operation of the printing device 10 will be described.

[0078] First, a printing process is performed, that is, the printing unit 16 prints the printed material P on the upper surface 12a of the transfer sheet 12. Figure 1 In the printing process shown, ink is supplied to the head unit 20. The first circulation portion 36a of the transfer sheet 12 is disposed below the head unit 20.

[0079] In response to a control signal from the control device 18, ink is ejected vertically downward from the nozzles of the nozzle assembly 20 onto the upper surface 12a of the transfer sheet 12. While ejecting ink, the nozzle assembly 20 moves multiple times in the forward and backward directions and widthwise directions along the first and second guide rails 40 and 42 in accordance with the print pattern of the printed object P. In this manner, the upper surface 12a of the transfer sheet 12 is coated with ink by ejecting ink multiple times. A printed object P having a printed pattern is formed on the upper surface 12a of the transfer sheet 12.

[0080] In parallel with the printing process of the printed material P by the nozzle assembly 20, a first curing process is performed, in which the first curing sections 44a and 44b irradiate the printed material P with the first irradiation light L1. In the first curing process, the first irradiation device 46 of the first curing sections 44a and 44b irradiates the printed material P with the first irradiation light L1, which is UV radiation, in response to a control signal from the control device 18. The first irradiation light L1 is irradiated vertically downward from the first curing sections 44a and 44b toward the printed material P on the transfer sheet 12. When the first irradiation light L1 is irradiated onto the printed material P, the printed material P formed of UV-curable ink begins to cure.

[0081] At this time, the first irradiation intensity of the first irradiation light L1 is less than the irradiation intensity required to completely cure the printed object P. The first irradiation intensity of the first irradiation light L1 from the first irradiation device 46 is controlled based on a control signal from the control device 18. As a result, the printed object P is not completely cured but is in a semi-cured state. The semi-cured state refers to, for example, a gel-like state in which a portion of liquid ink has solidified.

[0082] After the printed material P is printed on the transfer sheet 12 by the printing unit 16 and semi-cured by the first curing units 44a and 44b, the ink ejection by the head unit 20 is stopped. The irradiation of the first irradiation light L1 by the first curing units 44a and 44b is stopped.

[0083] Next, a conveying process is performed, that is, the printed matter P printed on the transfer sheet 12 is moved to the transfer section 17 (see FIG. Figure 3 At this time, the housing 60 of the transfer unit 17 is raised by the lifting mechanism 52, and the housing 60 and the cover 62 are separated from each other in the vertical direction.

[0084] exist Figure 3In the illustrated conveying process, the rotation mechanism 24 of the conveying unit 14 is driven based on a control signal from the control device 18. The motor 34 is driven to rotate the drive roller 26 clockwise. As the drive roller 26 rotates, the endless transfer sheet 12 rotates clockwise. As the transfer sheet 12 rotates, the first to third driven rollers 28, 30, and 32 also rotate clockwise.

[0085] When the transfer sheet 12 rotates, the first circulating portion 36a of the transfer sheet 12 on which the printed matter P is printed moves forward. At this time, since the transfer sheet 12 is in an endless belt shape, the third circulating portion 36c of the transfer sheet 12 moves backward.

[0086] The printed material P moves forward by the rotation of the transfer sheet 12. Figure 3 When the printed material P shown reaches the transfer section 17, the drive of the motor 34 is stopped according to a control signal from the control device 18. Consequently, the rotation of the drive roller 26 stops, and the movement (rotation) of the transfer sheet 12 also stops. The printed material P is arranged between the base 58 (cover 62) and the housing 60 that constitute the transfer section 17. The printed material P faces the transfer surface W1 of the workpiece W held by the support 70. The printed material P is arranged below the transfer surface W1 of the workpiece W. In other words, the transfer surface W1 of the workpiece W is arranged above the printed material P on the transfer sheet 12.

[0087] Next, a sealing process is performed, that is, before the printed material P is transferred to the transfer surface W1 of the workpiece W, a space 56 sealed in the receiving portion 48 is formed (see Figure 4 ).

[0088] The lifting mechanism 52 is driven by a control signal from the control device 18. The lifting arm 76 of the lifting mechanism 52 lowers the box body 60. As the box body 60 is lowered, the second sealing portion 66 of the box body 60 abuts against the first sealing portion 64 of the cover 62 (see FIG. Figure 4 The airtightness between the housing 60 and the lid 62 is maintained by the first sealing portion 64 and the second sealing portion 66. A sealed space 56 surrounded by the housing 60 and the lid 62 is formed inside the accommodating portion 48. The transfer sheet 12 is disposed between the first sealing portion 64 and the second sealing portion 66.

[0089] The space 56 is vertically partitioned into a first space portion 78 and a second space portion 80. The first space portion 78 is enclosed by the upper surface 12a of the transfer sheet 12 and the housing 60, while the second space portion 80 is enclosed by the lower surface 12b of the transfer sheet 12 and the cover 62 (base 58). In other words, the space 56 is divided vertically into two portions by the transfer sheet 12, and the portions are airtightly separated from each other.

[0090] Next, a transfer process is performed to transfer the printed matter P printed on the transfer sheet 12 to the transfer surface W1 of the workpiece W (see FIG. Figure 5 ).

[0091] In response to a control signal from the control device 18, negative pressure fluid is supplied from the negative pressure fluid supply source of the pressure regulating unit 54 to the first space 78. Negative pressure fluid is supplied from the negative pressure fluid supply source to the first space 78 through the plurality of communication holes 72. The pressure of the first space 78 is reduced from atmospheric pressure by the negative pressure fluid. The pressure of the second space 80 is maintained at atmospheric pressure. By supplying negative pressure fluid to the first space 78, the pressure of the first space 78 becomes lower than the pressure of the second space 80. A pressure difference is generated between the pressure of the first space 78 and the pressure of the second space 80.

[0092] Negative pressure fluid is supplied to the first space portion 78 through the connecting hole 72, and the upper surface 12a of the transfer sheet 12 is sucked upward from the opening of the connecting hole 72. When the upper surface 12a of the transfer sheet 12 moves upward, the printed material P moves toward the workpiece W together with the transfer sheet 12. The upper surface 12a of the transfer sheet 12 abuts against the transfer surface W1 of the workpiece W. When the transfer sheet 12 is further sucked upward, the elastic transfer sheet 12 stretches along the transfer surface W1 and deforms into a curved shape. The upper surface 12a of the transfer sheet 12 is strongly pressed against the transfer surface W1 of the workpiece W by the upward suction caused by the negative pressure fluid.

[0093] The printed material P printed on the transfer sheet 12 is deformed to curve along the transfer surface W1 of the workpiece W and is pressed against the transfer surface W1. The printed material P is semi-cured by the first curing sections 44a and 44b. Therefore, when the printed material P is pressed against the transfer surface W1 of the workpiece W together with the transfer sheet 12, the printed material P does not crack. The semi-cured printed material P can be appropriately curved along the transfer surface W1 for transfer.

[0094] Next, a sealing release step is performed, in which the first space portion 78 of the housing portion 48 is opened to the atmosphere to release the sealing of the space 56 .

[0095] After the printed material P is transferred to the transfer surface W1 of the workpiece W, the supply of negative pressure fluid from the negative pressure fluid supply source to the first space portion 78 is stopped according to the control signal from the control device 18. The lifting mechanism 52 is driven according to the control signal from the control device 18. By driving the lifting mechanism 52, the box 60 and the lifting arm 76 are lifted up together (see FIG. Figure 6 When the box body 60 rises and separates upward from the cover portion 62 , the first sealing portion 64 and the second sealing portion 66 separate, thereby releasing the seal of the space 56 .

[0096] As a result, the first space 78 of the space 56 is opened to the atmosphere. The pressure in the first space 78 reaches atmospheric pressure. The pressure in the first space 78 becomes the same as the pressure in the second space 80. The pressure difference between the pressure in the first space 78 and the pressure in the second space 80 is eliminated.

[0097] The transfer sheet 12 falls downward from the transfer surface W1 of the workpiece W due to its own weight. The transfer sheet 12 becomes horizontal again and is arranged above the cover 62 .

[0098] Finally, the second curing step is performed to completely cure the printed material P transferred onto the transfer surface W1 of the workpiece W (see Figure 6 ).

[0099] In response to a control signal from the control device 18, the second irradiation device 51 of the second curing unit 50 irradiates the second irradiation light L2 upward. The second irradiation light L2 is irradiated from the second curing unit 50 toward the printed material P transferred onto the transfer surface W1 of the workpiece W. When the second irradiation light L2 is irradiated toward the printed material P at the second irradiation intensity, the printed material P, formed of UV-curable ink, is completely cured. The second irradiation intensity of the second irradiation light L2 is sufficient to completely cure the printed material P. The second irradiation intensity is greater than the first irradiation intensity of the first irradiation light L1. Consequently, the printed material P is completely cured on the transfer surface W1 of the workpiece W.

[0100] Then, the workpiece W to which the printed matter P has been transferred is removed from the support sheet 74 of the support body 70. Thus, the printing operation of printing the printed matter P on the transfer surface W1 of the workpiece W is completed.

[0101] Next, refer to Figures 7 to 11 , a case where a plurality of printed materials P are continuously printed and the printed materials P are sequentially transferred onto a workpiece W will be described. Here, a case where three printed materials with different print patterns, namely first to third printed materials P1, P2, and P3, are transferred onto the workpiece W will be described.

[0102] First, a first printing step is performed in which a first printed product P1 is printed on the transfer sheet 12 .

[0103] In the first printing process, Figure 7 As shown, the first printed material P1 is printed by the printing unit 16 onto the upper surface 12 a of the first circulation portion 36 a of the transfer sheet 12 .

[0104] Next, the first conveying step is performed, that is, the transfer sheet 12 printed with the first printed matter P1 is moved to the transfer section 17 by the conveying section 14. In the first conveying step, the transfer sheet 12 is rotated by driving the rotating mechanism 24 of the conveying section 14. The first printed matter P1 is conveyed to the transfer section 17 by rotating the transfer sheet 12. After the first conveying step, the first transfer step (see FIG. 1 ) is performed to transfer the first printed matter P1 to the transfer surface W1 of the workpiece W. Figure 8 ).

[0105] like Figure 8 As shown, the transfer sheet 12 is suctioned by the transfer unit 17, transferring the first printed object P1 onto the transfer surface W1 of the workpiece W. While the first transfer step is being performed, the second printing step of printing the second printed object P2 is performed in parallel in the printing unit 16. In the second printing step, the printing unit 16 prints the second printed object P2 on the upper surface 12a of the transfer sheet 12. The second printed object P2, for example, has a different printed pattern than the first printed object P1. In other words, the first transfer step, which is the transfer step of the first printed object P1, and the second printing step, which is the printing step of the second printed object P2, are performed in parallel.

[0106] In the first transfer process, after the transfer of the first printed material P1 to the transfer surface W1 of the workpiece W is completed in the transfer section 17, the second irradiation light L2 is irradiated from the second curing section 50 to the first printed material P1. The first printed material P1 is completely cured on the transfer surface W1 of the workpiece W by the second irradiation light L2. After the first transfer process is completed and the printing of the second printed material P2 by the printing section 16 in the second printing process is completed, the second conveying process is performed, that is, the transfer sheet 12 is rotated by the conveying section 14 to convey the second printed material P2 to the transfer section 17 (see Figure 9 At this time, the transfer sheet 12 rotates so that the first to fourth circulation sections 36a, 36b, 36c, and 36d circulate clockwise.

[0107] Next, in the transfer unit 17, a second transfer process ( Figure 10), the first printed matter P1 is transferred to the workpiece W. The second printed matter P2 rises together with the transfer sheet 12 due to the negative pressure fluid supplied to the first space portion 78. The second printed matter P2 abuts and is pressed against the surface of the first printed matter P1. Accordingly, on the transfer surface W1 of the workpiece W, the second printed matter P2 is transferred to the surface of the first printed matter P1. On the transfer surface W1, the first printed matter P1 and the second printed matter P2 are stacked. After the second transfer process is completed, the second printed matter P2 is irradiated with the second irradiation light L2 from the second curing unit 50. The second printed matter P2 is cured on the surface of the first printed matter P1. Two layers of printed matter, namely the first printed matter P1 and the second printed matter P2, which are different from the printed pattern, are formed on the transfer surface W1 of the workpiece W.

[0108] In progress Figure 10 During the second transfer process of the second printed product P2 shown, the third printing process of printing the third printed product P3 is performed in parallel in the printing unit 16. In the third printing process, the printing unit 16 prints the third printed product P3 on the upper surface 12a of the transfer sheet 12. The third printed product P3 has a different printed pattern than the first printed product P1 and the second printed product P2, for example.

[0109] After the second transfer step and the third printing step are completed, a third transport step is performed in which the transport unit 14 rotates the transfer sheet 12 to transport the third printed product P3 to the transfer unit 17 .

[0110] The third transfer step is performed in the transfer section 17, that is, the third printed matter P3 is transferred to the surface of the second printed matter P2 transferred onto the workpiece W ( Figure 11 The third printed object P3 is lifted up together with the transfer sheet 12 by the negative pressure fluid supplied to the first space 78. The third printed object P3 abuts against and is pressed against the surface of the second printed object P2 transferred onto the workpiece W.

[0111] Accordingly, the third printed material P3 is transferred onto the surface of the second printed material P2 on the transfer surface W1 of the workpiece W. On the transfer surface W1, the first to third printed materials P1, P2, and P3 are stacked in sequence. After the third transfer process is completed, the second irradiation light L2 is irradiated from the second curing unit 50 onto the third printed material P3. The third printed material P3 is cured on the surface of the third printed material P3. Three layers of printed materials with different printed patterns, namely the first to third printed materials P1, P2, and P3, are formed and cured on the transfer surface W1 of the workpiece W. Accordingly, the printing operation of printing the first to third printed materials P1, P2, and P3 on the transfer surface W1 of the workpiece W is completed. By overlapping the multiple first to third printed materials P1, P2, and P3, the surface of the instrument panel, which is the workpiece W, can have a three-dimensional texture.

[0112] As described above, in an embodiment of the present invention, there is a transfer section 17, which prints the printed material P on the upper surface 12a of the transfer sheet 12 through the printing section 16, and transfers the printed material P to the transfer surface W1 of the workpiece W. The printed material P that is semi-cured by the first irradiation light L1 of the first curing section 44a, 44b is pressed and transferred to the transfer surface W1 of the workpiece W through the pressure difference between the first space section 78 and the second space section 80 generated by the pressure adjustment section 54.

[0113] Therefore, by transferring the flexible printed material P onto the transfer surface W1 of the workpiece W before it is completely cured, the printed material P can be transferred along the transfer surface W1. By sucking the transfer sheet 12 toward the workpiece W using a pressure difference, the printed material P can be pressed onto the transfer surface W1 of the workpiece W through the transfer sheet 12 so as to be fused to the transfer surface W1.

[0114] As a result, regardless of the shape of the transfer surface W1 of the workpiece W, the printed material P can be transferred onto the transfer surface W1 with high accuracy, and the manufacturability can be improved by suppressing the occurrence of cracks in the printed material P.

[0115] By using UV-curable ink as the ink, the printed material P printed on the transfer sheet 12 can be quickly semi-cured by the first irradiation light L1 of the first curing units 44a and 44b. The printed material P transferred to the transfer surface W1 of the workpiece W can be quickly and reliably completely cured by the second irradiation light L2 of the second curing unit 50.

[0116] The transfer sheet 12 is provided as an endless belt body facing the printing section 16 and the transfer section 17, and the transfer sheet 12 is rotated by the rotation mechanism 24 of the conveying section 14. Thus, the endless transfer sheet 12 is continuously rotated by the rotation mechanism 24, so that the transfer sheet 12 can be used to continuously print the printed material P and transfer the printed material P to the workpiece W. This allows for efficient printing of the printed material P and transfer of the printed material P to the workpiece W.

[0117] By printing the printed material P on the upper surface 12a of the transfer sheet 12, the printed material P can be properly held on the upper surface 12a of the transfer sheet 12, compared to the case where the printed material P is printed on the lower surface 12b of the transfer sheet 12. This can suppress distortion of the printed pattern of the printed material P, and the printed material P can be transferred to the transfer surface W1 of the workpiece W with high precision.

[0118] The transfer sheet 12 is provided with a downwardly open housing 60 and a cover 62 disposed on a base 58 below the housing 60. When the housing 60 descends and contacts the cover 62, the pressure in the first space 78 of the space 56 enclosed by the housing 60 and the cover 62 is lowered than that in the second space 80. Consequently, the pressure difference between the first space 78 and the second space 80 causes the transfer sheet 12 to move toward the workpiece W within the first space 78, allowing the printed material P to contact and be transferred to the transfer surface W1 of the workpiece W.

[0119] When the workpiece W is a dashboard mounted on an automobile, and the transfer surface W1 is a curved, non-flat surface, placing an uncured printed material P in contact with the transfer surface W1 allows the printed material P to be bent along the curved surface, allowing for high-precision transfer. By providing the printed material P with flexibility, cracks can be prevented even when transferred onto the curved transfer surface W1.

[0120] It has a printing process and a transfer process. In the printing process, the printed material P is printed on the upper surface 12a of the transfer sheet 12 by the nozzle component 20 of the printing unit 16, and a part of the printed material P is cured by the first curing unit 44a, 44b; in the transfer process, a pressure difference is generated between the first space portion 78 and the second space portion 80 of the accommodating portion 48, and the printed material P is pressed in the first space portion 78 by the pressure difference and transferred to the transfer surface W1 of the workpiece W.

[0121] By transferring the printed material P, which has been semi-cured in the printing process, to the transfer surface W1 of the workpiece W in the transfer process, the printed material P can be transferred to the workpiece W with high precision without causing cracks or the like. By utilizing the pressure difference between the first space 78 and the second space 80, the printed material P printed on the transfer sheet 12 is pressed against the transfer surface W1 of the workpiece W for transfer, thereby allowing the printed material P to be transferred to the workpiece W with high precision without causing cracks or the like.

[0122] In the printing device 10, a printing process, a first curing process, a sealing process, a transfer process, and a second curing process are repeated as a cycle, thereby printing a plurality of first to third printed products P1, P2, and P3 in layers on the transfer surface W1 of the workpiece W. The printing unit 16 then performs the next printing process in parallel with the transfer process or the second curing process. Consequently, when the plurality of first to third printed products P1 to P3 are continuously transferred onto a single workpiece W, the second printing process for the next printed product P (the second printed product P2) is performed in parallel with the transfer process or the second curing process for the previous printed product (the first printed product P1). This improves the efficiency of the transfer process for the first to third printed products P1, P2, and P3.

[0123] During the printing process, the printing unit 16 prints the printed material P on the upper surface 12a of the transfer sheet 12, thereby suppressing distortion of the printed material P on the transfer sheet 12. Therefore, the printed material P can be brought into contact with the transfer surface W1 of the downwardly facing workpiece W from below and efficiently transferred.

[0124] The above-mentioned embodiments are summarized as follows.

[0125] The above embodiment is a printing device (10) that ejects ink to form printed matter (P, P1 to P3) on a transfer sheet (12), and transfers the printed matter from the transfer sheet to a transfer surface (W1) of a workpiece (W), characterized in that:

[0126] It comprises a printing unit (16), a transfer unit (17), a conveying unit (14), a first curing unit (44a, 44b) and a second curing unit (50), wherein:

[0127] The printing unit has a nozzle component (20) for ejecting the ink, and forms the printed matter on the first surface (12a) which is one side of the transfer sheet;

[0128] The transfer unit transfers the printed matter from the transfer sheet to the transfer surface of the workpiece;

[0129] The transport unit transports the printed portion of the transfer sheet on which the printed matter is printed from the printing unit to the transfer unit;

[0130] The first curing unit semi-cures the printed matter printed on the transfer sheet;

[0131] The second curing unit completely cures the printed matter transferred to the workpiece.

[0132] The transfer unit has a receiving portion (48) and a pressure adjustment portion (54), wherein:

[0133] The receiving portion has a space (56) capable of receiving the workpiece and the printing portion, and can receive a portion of the transfer sheet in such a manner that the printed matter printed on the transfer sheet faces the workpiece, wherein the space is divided into a first space portion (78) and a second space portion (80) by the transfer sheet, wherein the first space portion faces the first surface of the transfer sheet, and the second space portion faces the second surface (12b) which is the other surface of the transfer sheet;

[0134] The pressure adjustment unit generates a pressure difference between the first space and the second space such that the pressure in the first space is lower than the pressure in the second space.

[0135] The ink is an active energy ray curable ink that is cured by active energy rays,

[0136] The first curing section is a first irradiation device (46) for irradiating the printed matter of the transfer sheet with the active energy ray, and the second curing section is a second irradiation device (51) for irradiating the transfer surface of the workpiece with the active energy ray.

[0137] The transfer sheet is annular.

[0138] The conveying section includes a rotating mechanism (24) that rotates the transfer sheet to convey the printed matter formed on the transfer sheet from the printing section to the transfer section.

[0139] The first surface of the transfer sheet on which the printed matter is printed is the upper surface of the transfer sheet.

[0140] The pressure adjustment unit generates the pressure difference to transfer the printed matter onto the workpiece, and the workpiece is arranged above the transfer sheet in the space of the storage unit.

[0141] The receiving portion comprises a box body (60) having an opening at one end and a cover body (62) for sealing the opening of the box body.

[0142] The box body can be displaced toward or away from the cover body.

[0143] When the transfer sheet is held between the box and the cover, the space is formed.

[0144] The first space is a space surrounded by the box and the transfer sheet.

[0145] The second space portion is a space surrounded by the cover and the transfer sheet.

[0146] A printing method comprising: ejecting ink in a printing unit to form a printed matter on a transfer sheet, and transferring the printed matter from the transfer sheet to a transfer surface of a workpiece, wherein:

[0147] The method comprises a printing step, a first curing step, a sealing step, a transfer step and a second curing step, wherein:

[0148] In the printing step, the ink is ejected from the nozzle member of the printing unit onto a first surface, which is one surface of the transfer sheet, to form the printed material.

[0149] In the first curing step, the printed matter printed on the transfer sheet is semi-cured;

[0150] In the sealing step, the printing portion of the transfer sheet on which the printed matter is printed is made to face the transfer surface of the workpiece accommodated in the space of the accommodation portion, the space of the accommodation portion is sealed, and the space is divided into a first space portion and a second space portion by the transfer sheet, wherein the first space portion faces the first surface of the transfer sheet, and the second space portion faces the second surface, which is the other surface of the transfer sheet;

[0151] In the transfer step, a pressure difference is generated between the first space portion and the second space portion in which the workpiece is accommodated, so that the printed matter on the transfer sheet moves toward the transfer surface of the workpiece and the printed matter is transferred to the transfer surface;

[0152] In the second curing step, the printed portion transferred to the transfer surface of the workpiece is completely cured.

[0153] The printing step, the first curing step, the sealing step, the transfer step, and the second curing step are repeated as one cycle to perform laminated printing.

[0154] In parallel with the transfer step or the second curing step, the printing unit performs the next printing step.

[0155] In the printing step, the printed matter is formed on the first surface, which is the upper surface of the transfer sheet, by the printing unit.

[0156] In the transfer step, the printed matter is transferred onto a transfer surface of the workpiece disposed above the transfer sheet.

[0157] In addition, the present invention is not limited to the above-described embodiment, and various structures can be adopted without departing from the gist of the present invention.

Claims

1. A printing device that ejects ink to form a printed matter on a transfer sheet and transfers the printed matter from the transfer sheet to a transfer surface of a workpiece, characterized in that: It has a printing unit, a transfer unit, a conveying unit, a first curing unit and a second curing unit, wherein: The printing unit includes a nozzle member for ejecting the ink, and forms the printed matter on a first surface, which is one surface of the transfer sheet. The transfer unit transfers the printed matter from the transfer sheet to the transfer surface of the workpiece; The transport unit transports the printed portion of the transfer sheet on which the printed matter is printed from the printing unit to the transfer unit; The first curing unit semi-cures the printed matter printed on the transfer sheet; The second curing unit completely cures the printed matter transferred to the workpiece. The transfer unit includes a receiving unit and a pressure adjustment unit, wherein: The receiving portion has a space capable of receiving the workpiece and the printing portion, and is capable of receiving a portion of the transfer sheet in such a manner that the printed matter printed on the transfer sheet faces the workpiece, wherein the space is divided into a first space portion and a second space portion by the transfer sheet, wherein the first space portion faces the first surface of the transfer sheet, and the second space portion faces the second surface which is the other surface of the transfer sheet; The pressure regulating unit generates a pressure difference between the first space and the second space such that the pressure in the first space is lower than the pressure in the second space. The receiving portion comprises a box body and a cover body, wherein One end of the box body has an opening and is provided with the pressure adjustment part; The cover is arranged in a movable manner relative to the box body to block the opening of the box body. The second curing portion is disposed on the cover.

2. The printing device according to claim 1, wherein The ink is an active energy ray curable ink that is cured by active energy rays, The first curing section is a first irradiation device that irradiates the printed matter on the transfer sheet with the active energy ray, and the second curing section is a second irradiation device that irradiates the transfer surface of the workpiece with the active energy ray.

3. The printing device according to claim 1 or 2, characterized in that The transfer sheet is annular. The transport section includes a rotation mechanism that rotates the transfer sheet to transport the printed matter formed on the transfer sheet from the printing section to the transfer section.

4. The printing device according to claim 1 or 2, characterized in that The first surface of the transfer sheet on which the printed matter is printed is the upper surface of the transfer sheet. The pressure adjustment section generates the pressure difference to transfer the printed matter onto the workpiece disposed above the transfer sheet in the space of the storage section.

5. The printing device according to claim 1 or 2, characterized in that: When the transfer sheet is held between the box and the cover, the space is formed. The first space is a space surrounded by the box and the transfer sheet. The second space portion is a space surrounded by the cover and the transfer sheet.

6. A printing method comprising: ejecting ink in a printing unit to form a printed matter on a transfer sheet, and transferring the printed matter from the transfer sheet to a transfer surface of a workpiece, wherein: The method comprises a printing step, a first curing step, a sealing step, a transfer step and a second curing step, wherein: In the printing step, the ink is ejected from the nozzle member of the printing unit onto a first surface, which is one surface of the transfer sheet, to form the printed material. In the first curing step, the printed matter printed on the transfer sheet is semi-cured by a first curing unit; In the sealing step, the printing portion of the transfer sheet on which the printed matter is printed is made to face the transfer surface of the workpiece accommodated in the space of the accommodation portion, the space of the accommodation portion is sealed, and the space is divided into a first space portion and a second space portion by the transfer sheet, wherein the first space portion faces the first surface of the transfer sheet, and the second space portion faces the second surface, which is the other surface of the transfer sheet; In the transfer step, a pressure difference is generated between the first space portion and the second space portion in which the workpiece is accommodated, so that the printed matter on the transfer sheet moves toward the transfer surface of the workpiece and the printed matter is transferred to the transfer surface; In the second curing step, the printed portion transferred to the transfer surface of the workpiece is completely cured. The sealing step is performed by relatively moving the cover and the box of the storage portion facing each other with the transfer sheet interposed therebetween. The second curing step is performed by a second curing portion provided on the cover.

7. The printing method according to claim 6, characterized in that The printing step, the first curing step, the sealing step, the transfer step, and the second curing step are repeated as one cycle to perform laminated printing. In parallel with the transfer step or the second curing step, the printing unit performs the next printing step.

8. The printing method according to claim 6 or 7, characterized in that: In the printing step, the printed matter is formed on the first surface, which is the upper surface of the transfer sheet, by the printing unit. In the transfer step, the printed matter is transferred onto a transfer surface of the workpiece disposed above the transfer sheet.

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