Printing apparatus and method for maintaining the printing apparatus

Abstract

The present invention provides a printing apparatus that performs inkjet printing on one side of the adhesive layer of a medium having an adhesive layer and a release sheet, and that prevents the adhesive from sticking to the pinch roller even when the medium is transported using a pinch roller that comes into contact with the adhesive layer. [Solution] The printing apparatus 1 comprises a printing mechanism 11 for printing on the adhesive layer of a medium 3 having an adhesive layer and a release sheet, and a medium transport mechanism 12 for transporting the medium 3. The medium transport mechanism 12 comprises a drive roller 45 that contacts the release sheet, and a pinch roller 46 that is positioned opposite the drive roller 45 and contacts the adhesive layer. At least the surface of the pinch roller 46 is made of silicone rubber, and the arithmetic mean roughness Ra of the surface of the pinch roller 46 is 0.1 μm or more and 0.5 μm or less.

Description

Technical Field

[0001] The present invention relates to a printing apparatus that performs printing by an inkjet method on one surface of an adhesive layer of a medium having the adhesive layer and a release sheet. The present invention also relates to a maintenance method for such a printing apparatus.

Background Art

[0002] Conventionally, an image transfer sheet for transferring an arbitrary image to a transfer target object is known (see, for example, Patent Document 1). The image transfer sheet described in Patent Document 1 includes an upper transfer film, a release sheet, an adhesive layer formed on the upper surface of the release sheet, and an image layer disposed between the adhesive layer and the transfer film. The image layer is directly printed on the upper surface of the adhesive layer by an inkjet printer or the like.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0004] The inventor of the present application is developing a printing apparatus that performs printing by an inkjet method on one surface of an adhesive layer of a medium having the adhesive layer and a release sheet. The printing apparatus under development includes a printing mechanism for performing printing by an inkjet method on the adhesive layer of the medium having the release sheet disposed on one side of the adhesive layer, and a medium transport mechanism for transporting the medium.

[0005] The inventors of the present invention decided to improve the accuracy of media transport in a printing apparatus under development by using a drive roller that contacts a release sheet located on one side of the adhesive layer, and a pinch roller that is positioned opposite the drive roller and also contacts the adhesive layer, in order to improve the printing accuracy on the media. However, the inventors of the present invention have found that in this printing apparatus under development, the adhesive from the adhesive layer may stick to the pinch roller that contacts the adhesive layer, potentially hindering the transport of the media.

[0006] Therefore, the object of the present invention is to provide a printing apparatus that performs inkjet printing on one side of the adhesive layer of a medium having an adhesive layer and a release sheet, and that can prevent the adhesive from sticking to the pinch roller even when the medium is transported using a pinch roller that comes into contact with the adhesive layer.

[0007] Furthermore, an object of the present invention is to provide a maintenance method for a printing apparatus that performs inkjet printing on one side of the adhesive layer of a medium having an adhesive layer and a release sheet, and that prevents the adhesive from sticking to the pinch roller even when the medium is transported using the pinch roller that comes into contact with the adhesive layer for a long period of time. [Means for solving the problem]

[0008] To solve the above problems, the inventors of this invention conducted various studies. As a result, the inventors of this invention found that by appropriately setting the surface roughness of the pinch roller, it is possible to prevent the adhesive from sticking to the pinch roller in contact with the adhesive layer. Furthermore, the inventors of this invention found that by using a specific material for the surface of the pinch roller, it is possible to prevent the adhesive from sticking to the pinch roller in contact with the adhesive layer. Moreover, the inventors of this invention found that by using a specific material for the surface of the pinch roller and setting the surface roughness of the pinch roller to a specific value, it is possible to prevent the adhesive from sticking to the pinch roller in contact with the adhesive layer. Furthermore, the inventors of this invention found that by applying a release agent to the surface of the pinch roller, it is possible to prevent the adhesive from sticking to the pinch roller in contact with the adhesive layer.

[0009] The printing apparatus of the present invention is based on the aforementioned new findings and comprises a printing mechanism for printing on the adhesive layer of a medium having an adhesive layer and a release sheet disposed on one side of the adhesive layer using an inkjet method, and a medium transport mechanism for transporting the medium, wherein the medium transport mechanism comprises a drive roller that contacts the release sheet and a pinch roller that is disposed opposite the drive roller and contacts the adhesive layer, and at least the surface of the pinch roller is made of silicone rubber, and the arithmetic mean roughness Ra of the surface of the pinch roller is 0.1 μm or more and 0.5 μm or less.

[0010] In the printing apparatus of the present invention, at least the surface of the pinch roller is made of silicone rubber, and the arithmetic mean roughness Ra of the pinch roller surface is 0.1 μm or more and 0.5 μm or less. Therefore, according to the inventors' research, the present invention makes it possible to prevent the adhesive from sticking to the pinch roller even when conveying a medium using a pinch roller that comes into contact with the adhesive layer.

[0011] In the present invention, it is preferable that the entire pinch roller is made of silicone rubber. With this configuration, it is possible to simplify the structure of the pinch roller compared to when the pinch roller includes a portion made of a material other than silicone rubber.

[0012] Furthermore, based on the new findings described above, the printing apparatus of the present invention comprises a printing mechanism for printing on the adhesive layer of a medium having an adhesive layer and a release sheet disposed on one side of the adhesive layer using an inkjet method, and a medium transport mechanism for transporting the medium, wherein the medium transport mechanism comprises a drive roller that contacts the release sheet and a pinch roller that is disposed opposite the drive roller and contacts the adhesive layer, and at least the surface of the pinch roller is formed of non-adhesive silicone rubber.

[0013] In the printing apparatus of the present invention, at least the surface of the pinch roller is made of non-adhesive silicone rubber. Therefore, according to the inventors' research, the present invention makes it possible to prevent adhesive from sticking to the pinch roller even when conveying a medium using a pinch roller that comes into contact with an adhesive layer.

[0014] In the present invention, it is preferable that the entire pinch roller is made of non-stick silicone rubber. With this configuration, it is possible to simplify the structure of the pinch roller compared to when the pinch roller includes a portion made of a material other than non-stick silicone rubber.

[0015] In the present invention, for example, the pinch roller may comprise an inner roller portion and a silicone tube whose inner surface is in close contact with the outer surface of the inner roller portion and which constitutes the surface of the pinch roller. In this case, it becomes possible to prevent adhesive from sticking to the pinch roller regardless of the material of the inner roller portion. In this case, for example, it becomes possible to prevent adhesive from sticking to the pinch roller by attaching the silicone tube to the outer surface of an existing pinch roller installed in a printing apparatus.

[0016] Furthermore, based on the new findings described above, the printing apparatus of the present invention comprises a printing mechanism for printing on the adhesive layer of a medium having an adhesive layer and a release sheet disposed on one side of the adhesive layer using an inkjet method, and a medium transport mechanism for transporting the medium, wherein the medium transport mechanism comprises a drive roller that contacts the release sheet and a pinch roller that is disposed opposite the drive roller and contacts the adhesive layer, and the surface of the pinch roller is coated with a release agent.

[0017] In the printing apparatus of the present invention, a release agent is applied to the surface of the pinch roller. Therefore, according to the inventors' research, the present invention makes it possible to prevent the adhesive from sticking to the pinch roller even when the medium is transported using a pinch roller that comes into contact with the adhesive layer.

[0018] In the present invention, for example, the mold release agent is silicone oil.

[0019] Furthermore, based on the new findings described above, the printing apparatus of the present invention comprises a printing mechanism for printing on the adhesive layer of a medium having an adhesive layer and a release sheet disposed on one side of the adhesive layer using an inkjet method, and a medium transport mechanism for transporting the medium, wherein the medium transport mechanism comprises a drive roller that contacts the release sheet and a pinch roller that is disposed opposite the drive roller and contacts the adhesive layer, and the surface roughness of the pinch roller is set to such a degree that the adhesive of the adhesive layer does not stick to the surface of the pinch roller.

[0020] In the printing apparatus of the present invention, the surface roughness of the pinch roller is set to such a degree that the adhesive of the adhesive layer does not adhere to the surface of the pinch roller. Therefore, in the present invention, even when conveying a medium using a pinch roller that comes into contact with the adhesive layer, it is possible to prevent the adhesive from adhering to the pinch roller.

[0021] In the present invention, the outer shape of the pinch roller is preferably a crown shape in which the outer diameter of the pinch roller decreases from the central portion of the pinch roller in the axial direction toward both ends. With this configuration, it is possible to prevent the edge (axial end portion) of the pinch roller from pushing the adhesive of the adhesive layer outward in the axial direction of the pinch roller. Accordingly, it is possible to prevent roller marks of the pinch roller from occurring on the adhesive layer.

[0022] In the present invention, for example, the printing mechanism includes an inkjet head that ejects white ink, an inkjet head that ejects color ink, and an inkjet head that ejects clear ink. In this case, it is possible to eject the required ink when needed.

[0023] In the present invention, the printing apparatus preferably includes a transfer sheet attaching portion for attaching a transfer sheet to a printed medium, and the transfer sheet attaching portion includes a heater for heating the printed medium. With this configuration, it is possible to attach the transfer sheet to the medium in a state where the medium and the transfer sheet are heated and softened in the transfer sheet attaching portion. Accordingly, it is possible to improve the adhesion of the transfer sheet attached to the adhesive layer in the transfer sheet attaching portion to the adhesive layer.

[0024] In the present invention, the arithmetic mean roughness Ra of the surface of the pinch roller is preferably 0.4 μm or less. With this configuration, it is possible to effectively prevent the adhesive from sticking to the pinch roller. Further, in this case, the arithmetic mean roughness Ra of the surface of the pinch roller is more preferably 0.3 μm or less. With this configuration, it is possible to more effectively prevent the adhesive from sticking to the pinch roller.

[0025] In the present invention, the printing apparatus preferably includes an ionizer for removing static electricity from the medium. With this configuration, it is possible to suppress adhesion of dust to the adhesive layer caused by static electricity. Accordingly, it is possible to suppress adhesion of dust to the adhesive layer.

[0026] Further, based on the above new findings, a maintenance method for a printing apparatus according to the present invention is a maintenance method for a printing apparatus that includes a printing mechanism for performing printing by an inkjet method on an adhesive layer of a medium having the adhesive layer and a release sheet disposed on one side of the adhesive layer, and a medium transport mechanism for transporting the medium, wherein the medium transport mechanism includes a drive roller that comes into contact with the release sheet, and a pinch roller disposed opposite to the drive roller and coming into contact with the adhesive layer, the maintenance method being characterized in that a release agent is applied to a surface of the pinch roller during maintenance of the printing apparatus.

[0027] In the maintenance method for a printing apparatus according to the present invention, a release agent is applied to the surface of the pinch roller during maintenance of the printing apparatus. Therefore, according to studies by the inventors of the present application, if the printing apparatus is maintained by the maintenance method of the present invention, adhesion of the adhesive to the pinch roller can be prevented even when the medium is transported using the pinch roller in contact with the adhesive layer for a long time. Effects of the Invention

[0028] As described above, in the printing apparatus of the present invention, even when the medium is transported using the pinch roller in contact with the adhesive layer, adhesion of the adhesive to the pinch roller can be prevented. Further, if the printing apparatus is maintained by the maintenance method of the present invention, adhesion of the adhesive to the pinch roller can be prevented even when the medium is transported using the pinch roller in contact with the adhesive layer for a long time. Brief Description of the Drawings

[0029] [Figure 1] It is a side view for explaining a configuration of a printing apparatus according to an embodiment of the present invention. [Figure 2]Figure 1 is a schematic diagram illustrating the configuration of the medium shown. [Figure 3] Figure 1 is a diagram illustrating the processing performed on the media in the printing apparatus shown. [Figure 4] Figure 1 is a front view illustrating the configuration of the drive roller, pinch roller, and other components shown in the figure. [Figure 5] This is a side view illustrating the configuration of a pinch roller according to another embodiment of the present invention. [Figure 6] This is a cross-sectional view illustrating the configuration of a pinch roller according to another embodiment of the present invention. [Figure 7] Figure 6 is a diagram illustrating the effect of the pinch roller. [Modes for carrying out the invention]

[0030] Embodiments of the present invention will be described below with reference to the drawings.

[0031] (Overall configuration of the printing device) Figure 1 is a side view illustrating the configuration of a printing apparatus 1 according to an embodiment of the present invention. Figure 2 is a schematic diagram illustrating the configuration of the medium 3 shown in Figure 1. Figure 3 is a diagram illustrating the processing performed on the medium 3 in the printing apparatus 1 shown in Figure 1.

[0032] The printing apparatus 1 in this embodiment is a device for printing on one side of the adhesive layer 2 of a medium 3 having an adhesive layer 2 using an inkjet method, and for attaching a transfer sheet (application sheet) 4 to the printed side of the adhesive layer 2. The medium 3 and the transfer sheet 4 are formed in a long, narrow strip shape. The medium 3 before printing and the medium 3 after the transfer sheet 4 has been attached are wound into a roll. The transfer sheet 4 before being attached to the medium 3 is also wound into a roll.

[0033] As shown in Figure 2(A), the medium 3 comprises a release sheet 5 positioned on one side of the adhesive layer 2 and a release sheet 6 positioned on the other side of the adhesive layer 2. The adhesive layer 2 is formed, for example, by a pressure-sensitive adhesive. The release sheets 5 and 6 are, for example, resin release films. The medium 3 is composed of, for example, the adhesive layer 2 and the release sheets 5 and 6. The release sheet 5 is in contact with one side of the adhesive layer 2, and the release sheet 6 is in contact with the other side of the adhesive layer 2. The release sheets 5 and 6 may also be paper release paper.

[0034] The widths of release sheets 5 and 6 are equal in the width direction of medium 3, which is perpendicular to the longitudinal direction of medium 3. In medium 3, release sheets 5 and 6 are positioned at the same location in the width direction of medium 3. The widths of release sheets 5 and 6 in the width direction of medium 3 are wider than the width of the adhesive layer 2 in the width direction of medium 3. In medium 3, the edge 2a of the adhesive layer 2 in the width direction of medium 3 is positioned inward in the width direction of medium 3 than the edge 5a of release sheet 5 and the edge 6a of release sheet 6 in the width direction of medium 3 (see Figure 2(B)).

[0035] Printing device 1 is, for example, a commercial inkjet printer. Printing device 1 continuously prints on medium 3 and continuously attaches transfer sheets 4 to medium 3. Printing device 1 prints on the adhesive layer 2 of medium 3 after the release sheet 5 has been peeled off. After printing, a printed layer 7 is formed on one side of the adhesive layer 2 of medium 3 (see Figure 3(A)). The release sheet 5 peeled off from medium 3 is wound into a roll. Printing device 1 also attaches the transfer sheet 4 so as to cover the entire surface of one side of the adhesive layer 2 where the printed layer 7 is formed (see Figure 3(B)).

[0036] The medium 3, on which the printed layer 7 is formed and the transfer sheet 4 is attached, is used to attach the printed layer 7 to the surface of a predetermined object to be transferred. When attaching the printed layer 7 to the surface of the object to be transferred, first, the release sheet 6 is peeled off. In that state, the adhesive layer 2 is pressed against the surface of the object to be transferred. After that, when the transfer sheet 4 is peeled off, the attachment of the printed layer 7 to the surface of the object to be transferred is completed.

[0037] The printing apparatus 1 includes a printing mechanism 11 for printing on the adhesive layer 2 of a medium 3 having an adhesive layer 2 and release sheets 5 and 6, after the release sheet 5 has been peeled off, using an inkjet method, and a medium transport mechanism 12 for transporting the medium 3. The printing apparatus 1 also includes a transfer sheet attachment unit 13 for attaching a transfer sheet 4 to the printed medium 3, a medium feed unit 14 to which a roll of unprinted medium 3 is attached, a medium winding unit 15 to which a roll of medium 3 with the transfer sheet 4 attached is attached, a release sheet winding unit 16 to which a roll of release sheet 5 is attached, a transfer sheet feed unit 17 to which a roll of transfer sheet 4 is attached, and an ionizer (static eliminator) 18 for suppressing static charge on the medium 3 after the release sheet 5 has been peeled off.

[0038] The media transport mechanism 12 transports the media 3 in the longitudinal direction of the media 3. That is, the media 3 is formed in an elongated shape with the transport direction of the media 3 by the media transport mechanism 12 being the longitudinal direction. The media feeding unit 14, the printing mechanism 11, the transfer sheet attachment unit 13, and the media winding unit 15 are arranged in this order in the transport direction of the media 3. The width direction of the media 3 handled by the printing device 1 is parallel to the horizontal direction. In the following description, the Y direction in Figure 1, which is the width direction of the media 3, will be referred to as the "left-right direction," and the X direction in Figure 1, which is perpendicular to the left-right direction and the up-down direction (vertical direction, Z direction in Figure 1, etc.), will be referred to as the "front-back direction." In the following description, the X1 direction side in Figure 1, etc., which is one side of the front-back direction, will be referred to as the "front" side, and the X2 direction side in Figure 1, etc., which is the opposite side, will be referred to as the "back" side.

[0039] The transfer sheet application section 13 is located in front of the printing mechanism 11. The media winding section 15 is located below the transfer sheet application section 13. The transfer sheet feeding section 17 is located in front of the crimping roller 83, which is part of the transfer sheet application section 13 and will be described later. The media feeding section 14 is located behind and below the printing mechanism 11. The release sheet winding section 16 is located below the media feeding section 14. The ionizer 18 is provided to remove static electricity from the media 3. The ionizer 18 is located behind the printing mechanism 11. The ionizer 18 is also located above the media 3 as it is being transported toward the printing mechanism 11. The ionizer 18 blows ions toward the upper surface of the media 3.

[0040] In the media dispensing unit 14, the media 3 before printing is wound into a roll. The rolled media 3 is rotatable with the left-right direction as the axis of rotation. The media dispensing unit 14 does not have a drive mechanism to rotate the rolled media 3. The rolled media 3 before printing rotates passively in response to the media 3 being transported by the media transport mechanism 12. In the media winding unit 15, the media 3 after the transfer sheet 4 has been attached is wound into a roll. The rolled media 3 is rotatable with the left-right direction as the axis of rotation. The media winding unit 15 is equipped with a media winding mechanism 43, which will be described later and constitutes part of the media transport mechanism 12. The media winding mechanism 43 rotates the rolled media 3.

[0041] In the release sheet winding section 16, the release sheet 5 peeled from the medium 3 is wound into a roll. The roll of release sheet 5 is rotatable with the left-right direction as the axis of rotation. As described above, the release sheet winding section 16 is located below the medium dispensing section 14. As shown in Figure 1, the release sheet 5 is peeled from the medium 3 in the medium dispensing section 14.

[0042] The release sheet winding section 16 is equipped with a release sheet winding mechanism that winds up the release sheet 5 peeled off from the medium 3. The release sheet winding mechanism is equipped with a motor as a drive source. The release sheet winding mechanism rotates the release sheet 5 wound into a roll. The release sheet winding mechanism is also equipped with a torque limiter located in the power transmission path from the motor. When the tension of the release sheet 5 between the medium dispensing section 14 and the release sheet winding section 16 exceeds a certain value, the torque limiter causes the roll of release sheet 5 to rotate freely.

[0043] In the transfer sheet dispensing unit 17, the transfer sheet 4 is wound into a roll before being attached to the medium 3. The roll of transfer sheet 4 is rotatable with the left-right direction as the axis of rotation. The transfer sheet dispensing unit 17 does not have a drive mechanism to rotate the roll of transfer sheet 4. In the transfer sheet dispensing unit 17, the roll of transfer sheet 4 rotates passively in response to the transport of the medium 3 by the medium transport mechanism 12.

[0044] (Configuration of the printing mechanism) The printing mechanism 11 includes an inkjet head 22 (hereinafter referred to as "head 22") that ejects ink onto the adhesive layer 2, a carriage 23 on which the head 22 is mounted, a carriage drive mechanism 24 that moves the carriage 23 back and forth in the left-right direction, which is the main scanning direction, and a guide rail 25 that guides the carriage 23 in the left-right direction. The carriage drive mechanism 24 includes, for example, a belt to which a portion is fixed to the carriage 23, a pulley through which the belt is stretched, and a motor for rotating the pulley.

[0045] The print head 22 ejects ink downwards. Multiple nozzles for ejecting ink are formed on the underside of the print head 22. The print head 22 is equipped with a piezoelectric element (piezo element) for ejecting ink from the nozzles. In this embodiment, the ink ejected by the print head 22 is UV-curable ink. The carriage 23 is equipped with a UV irradiator (not shown) that irradiates ultraviolet light toward the medium 3 to cure the UV ink ejected from the print head 22. The UV irradiator is equipped with a UV LED chip. In this embodiment, the print head 22 ejects white ink, color ink, and clear ink. Specifically, the printing mechanism 11 includes a print head 22 that ejects white ink, a print head 22 that ejects color ink, and a print head 22 that ejects clear ink. The print layer 7 is composed of a white ink layer, a color ink layer, and a clear ink layer that are stacked in order from the bottom onwards relative to the adhesive layer 2.

[0046] The printing mechanism 11 includes a platen 36 on which the printing medium 3 is placed. The platen 36 is located below the head 22 and carriage 23. The upper surface of the platen 36 is the medium-supporting surface on which the medium 3 is placed. When printing is performed by the printing mechanism 11, the thickness direction of the medium 3 (i.e., the thickness direction of the medium 3 placed on the platen 36) coincides with the vertical direction. When printing is performed by the printing mechanism 11, the adhesive layer 2 constitutes the upper surface of the medium 3. Before printing, the medium 3 is transported from the rear to the upper surface of the platen 36, and after printing, the medium 3 is transported from the upper surface of the platen 36 to the front.

[0047] (Configuration of the media transport mechanism) Figure 4 is a front view illustrating the configuration of the drive roller 45 and pinch roller 46 shown in Figure 1.

[0048] The media transport mechanism 12 includes a first media transport mechanism 42 that transports the media 3 from the media dispensing section 14 toward the platen 36, and a media winding mechanism 43 installed in the media winding section 15. In this embodiment, the media transport mechanism 12 is composed of the first media transport mechanism 42 and the media winding mechanism 43. As described above, in the media winding section 15, the media 3 after the transfer sheet 4 has been attached is wound into a roll. The media winding mechanism 43 rotates the roll-shaped media 3 with the left-right direction as the axis of rotation to wind up the media 3 after the transfer sheet 4 has been attached. The media winding mechanism 43 also transports the media 3 by winding it up.

[0049] The first media transport mechanism 42 includes a drive roller 45 that contacts the release sheet 6, a roller drive mechanism that drives the drive roller 45, and a pinch roller 46 that is positioned opposite the drive roller 45 and contacts the adhesive layer 2. The roller drive mechanism includes a motor as a drive source. The first media transport mechanism 42 includes one drive roller 45 and multiple pinch rollers 46. In this embodiment, the first media transport mechanism 42 includes 14 pinch rollers 46.

[0050] The drive roller 45 and the pinch rollers 46 are rotatable with the left-right direction as the axis of rotation. The drive roller 45 and the multiple pinch rollers 46 are positioned behind the platen 36 and upstream of the platen 36 in the direction of transporting the medium 3. The drive roller 45 and the multiple pinch rollers 46 transport the medium 3, with the release sheet 5 removed, sandwiched between the drive roller 45 and the multiple pinch rollers 46.

[0051] As described above, the release sheet winding section 16 is equipped with a release sheet winding mechanism that winds up the release sheet 5 peeled off from the medium 3, and the release sheet winding mechanism is equipped with a torque limiter located in the power transmission path from the motor. In this embodiment, the torque value of the torque limiter of the release sheet winding mechanism is set so that the medium 3 is transported without hindrance from the medium dispensing section 14 to the platen 36 by the first medium transport mechanism 42. More specifically, the torque value of the torque limiter of the release sheet winding mechanism is set so that the medium 3 is transported accurately from the medium dispensing section 14 to the platen 36 by the first medium transport mechanism 42.

[0052] The first media transport mechanism 42 includes a plurality of roller holding parts 47 that rotatably hold a plurality of pinch rollers 46. In this embodiment, the roller holding part 47 holds two pinch rollers 46, and the first media transport mechanism 42 has a total of seven roller holding parts 47. The two pinch rollers 46 held by the roller holding part 47 are arranged with a gap between them in the left-right direction. The seven roller holding parts 47 are arranged in the left-right direction. That is, 14 pinch rollers 46 are arranged in the left-right direction. The pinch rollers 46 are rotatably held at the front end of the roller holding part 47.

[0053] The roller holding section 47 is movable between a transportable position in which the pinch roller 46 contacts the adhesive layer 2 and a retracted position in which the pinch roller 46 retracts away from the adhesive layer 2 (i.e., retracts upward). Specifically, the roller holding section 47 is rotatable with respect to the frame (not shown) with the left-right direction as the axis of rotation between the transportable position and the retracted position.

[0054] The drive roller 45 is a metal roller. The drive roller 45 is formed in a slender cylindrical shape in the left-right direction. Numerous fine protrusions are formed on the surface of the drive roller 45 to increase the conveying force of the medium 3. Specifically, numerous fine protrusions are formed on the portion of the surface of the drive roller 45 that faces the pinch roller 46. In other words, the drive roller 45 is a grid roller.

[0055] The pinch roller 46 is formed in a cylindrical shape with its axial direction in the left-right direction. That is, the left-right direction (Y direction) is the axial direction of the pinch roller 46. The pinch roller 46 is also formed in a thin-walled cylindrical shape. The pinch roller 46 is fixed to the outer circumferential surface of a cylindrical core material 51 (see Figures 5 and 6), and the inner circumferential surface of the pinch roller 46 is in close contact with the outer circumferential surface of the core material 51. The core material 51 is made of, for example, metal or resin. The core material 51 is rotatably held in the roller holding part 47. The pinch roller 46 rotates together with the core material 51.

[0056] The pinch roller 46 is positioned above the drive roller 45 and is biased downward toward the drive roller 45. The pinch roller 46 is a rubber roller. In this embodiment, the pinch roller 46 is made of silicone rubber. Specifically, the entire pinch roller 46 is made of silicone rubber. That is, the surface of the pinch roller 46 is made of silicone rubber. The pinch roller 46 is manufactured by rubber molding using a mold. The hardness (rubber hardness) of the pinch roller 46 in this embodiment is 50°.

[0057] The surface roughness of the pinch roller 46 is set to such a degree that the adhesive of the adhesive layer 2 does not adhere to the surface of the pinch roller 46. The surface roughness of the pinch roller 46 that prevents the adhesive of the adhesive layer 2 from adhering to the surface of the pinch roller 46 has been determined in advance through experiments. In other words, in this embodiment, the surface roughness of the pinch roller 46 that prevents the adhesive of the adhesive layer 2 from adhering to the surface of the pinch roller 46 is determined experimentally, and the surface roughness of the pinch roller 46 is set to such a degree that the adhesive of the adhesive layer 2 does not adhere to the surface of the pinch roller 46.

[0058] The arithmetic mean roughness Ra of the pinch roller 46 surface is between 0.1 μm and 0.5 μm. In this embodiment, the arithmetic mean roughness Ra of the pinch roller 46 surface is reduced to 0.5 μm or less by mirror-finishing the surface of the mold used in the manufacture of the pinch roller 46. In addition, in this embodiment, if the arithmetic mean roughness Ra of the pinch roller 46 surface that transports the medium 3 during printing increases over time and exceeds 0.5 μm, the pinch roller 46 is replaced.

[0059] A release agent is applied to the surface of the pinch roller 46. That is, the surface of the pinch roller 46 is treated with a film by applying a release agent. In this embodiment, the release agent applied to the surface of the pinch roller 46 is silicone oil. Silicone oil is used when manufacturing the pinch roller 46 by rubber molding using a mold. After the manufacturing of the pinch roller 46, the release agent adheres to the surface of the pinch roller 46.

[0060] Furthermore, during maintenance of the printing device 1, a release agent is applied to the surface of the pinch roller 46. Specifically, when a predetermined length of media 3 is conveyed by the pinch roller 46, a release agent is applied to the surface of the pinch roller 46 during maintenance of the printing device 1. For example, when 500m of media 3 is conveyed by the pinch roller 46, the operator of the printing device 1 applies a release agent to the surface of the pinch roller 46 during maintenance of the printing device 1. Alternatively, the surface of the pinch roller 46 may be periodically coated with a release agent.

[0061] (Configuration of the transfer sheet application area) An after cover (after platen) 81 is positioned in front of the platen 36. The after cover 81 is made of metal. In this embodiment, the after cover 81 is made of steel plate. A convex curved guide surface 81a is formed on the surface of the after cover 81 for guiding the medium 3. The width of the guide surface 81a in the left-right direction is wider than the width of the medium 3. The medium 3 is transported along the guide surface 81a from the platen 36 toward the front, and then transported toward the downward. A heater 82 for heating the printed medium 3 is positioned inside the after cover 81. The heater 82 is positioned inside the after cover 81 so as to be aligned with the guide surface 81a.

[0062] The after cover 81 and heater 82 constitute part of the transfer sheet application section 13. That is, the transfer sheet application section 13 is equipped with the after cover 81 and heater 82 as a configuration for applying the transfer sheet 4 to the printed medium 3. The transfer sheet application section 13 is also equipped with a pressure roller 83 facing the front lower end of the after cover 81 from the front. The pressure roller 83 is made of foam material. In this embodiment, the pressure roller 83 is made of chloroprene rubber sponge. The pressure roller 83 is rotatable with the left-right direction as the axis of rotation. The length of the pressure roller 83 (length in the left-right direction) is longer than the width of the medium 3.

[0063] In the transfer sheet application section 13, the transfer sheet 4 is pressed against the medium 3 between the after cover 81 and the pressure roller 83 to adhere the transfer sheet 4 to the printed medium 3. When attaching the transfer sheet 4 to the medium 3, the medium 3 is heated by the heater 82. For example, the medium 3 is heated to 60-70°C by the heater 82. In other words, in the transfer sheet application section 13, the transfer sheet 4 is attached while heat is applied to the medium 3. The after cover 81 contacts the release sheet 6 from the rear. The pressure roller 83 contacts the transfer sheet 4 from the front. The pressure roller 83 is a driven roller that rotates in accordance with the medium 3 being transported by the medium transport mechanism 12, and there is no drive source for the pressure roller 83.

[0064] (Main effects of this form) As explained above, in this embodiment, the surface roughness of the pinch roller 46 is determined experimentally to be such that the adhesive of the adhesive layer 2 does not stick to the surface of the pinch roller 46, and the surface roughness of the pinch roller 46 is set to such a level that the adhesive of the adhesive layer 2 does not stick to the surface of the pinch roller 46. Specifically, in this embodiment, the pinch roller 46 is made of silicone rubber, and the arithmetic mean roughness Ra of the surface of the pinch roller 46 is 0.1 μm or more and 0.5 μm or less. Therefore, in this embodiment, even when the medium 3 is conveyed using the pinch roller 46 that is in contact with the adhesive layer 2, it is possible to prevent the adhesive from sticking to the pinch roller 46.

[0065] Furthermore, according to the inventors' research, in order to effectively prevent adhesive from sticking to the pinch roller 46 made of silicone rubber, it is preferable that the arithmetic mean roughness Ra of the surface of the pinch roller 46 be 0.4 μm or less. Moreover, in order to more effectively prevent adhesive from sticking to the pinch roller 46 made of silicone rubber, it is preferable that the arithmetic mean roughness Ra of the surface of the pinch roller 46 be 0.3 μm or less.

[0066] In this embodiment, a release agent is applied to the surface of the pinch roller 46. Therefore, according to the inventor's research, in this embodiment, even when the medium 3 is transported using the pinch roller 46 in contact with the adhesive layer 2, it is possible to prevent the adhesive from sticking to the pinch roller 46. Furthermore, in this embodiment, since a release agent is applied to the surface of the pinch roller 46 during maintenance of the printing apparatus 1, even when the medium 3 is transported using the pinch roller 46 in contact with the adhesive layer 2 for a long period of time, it is possible to prevent the adhesive from sticking to the pinch roller 46.

[0067] In this embodiment, the transfer sheet application section 13 is equipped with a heater 82 for heating the printed medium 3. Therefore, in this embodiment, the transfer sheet application section 13 can heat and soften the medium 3 and the transfer sheet 4, allowing the transfer sheet 4 to be applied to the medium 3. Consequently, in this embodiment, the adhesion of the transfer sheet 4 applied to the adhesive layer 2 in the transfer sheet application section 13 can be improved. Furthermore, in this embodiment, an ionizer 18 is installed to remove static electricity from the medium 3, making it possible to suppress the adhesion of dust to the adhesive layer 2 caused by static electricity. Consequently, in this embodiment, it is possible to suppress the adhesion of dust to the adhesive layer 2.

[0068] (Example 1 of changing the pinch roller) In the above-described embodiment, the pinch roller 46 may be made of non-stick silicone rubber. Specifically, the entire pinch roller 46 may be made of non-stick silicone rubber. That is, the surface of the pinch roller 46 may be made of non-stick silicone rubber. In this case as well, the hardness (rubber hardness) of the pinch roller 46 is 50°, similar to the above-described embodiment. In this modified example, since the surface of the pinch roller 46 is made of non-stick silicone rubber, according to the inventor's research, even when the medium 3 is conveyed using the pinch roller 46 that comes into contact with the adhesive layer 2, it becomes possible to prevent the adhesive from sticking to the pinch roller 46.

[0069] Furthermore, in this modified example, since the pinch roller 46 is made of non-adhesive silicone rubber, by performing regular maintenance on the pinch roller 46, it becomes possible to continue using the pinch roller 46 even after prolonged use, while preventing adhesive from sticking to the pinch roller 46. When maintaining the pinch roller 46, for example, the pinch roller 46 is washed with a neutral or alkaline detergent, and then the detergent adhering to the pinch roller 46 is rinsed off with water. A sponge or similar tool is also used when maintaining the pinch roller 46. Maintenance of the pinch roller 46 is performed, for example, when 1500m of medium 3 has been conveyed by the pinch roller 46, or when adhesive has stuck to the pinch roller 46 after relatively prolonged use.

[0070] (Example 2 of changing the pinch roller) Figure 5 is a side view illustrating the configuration of a pinch roller 46 according to another embodiment of the present invention.

[0071] In the above-described embodiment, the pinch roller 46 may include an inner roller portion 49 and a silicone tube 50 whose inner surface is in close contact with the outer surface of the inner roller portion 49 and which constitutes the surface of the pinch roller 46. In this modified example, the pinch roller 46 is composed of an inner roller portion 49 and a silicone tube 50. The inner roller portion 49 is formed in a thin-walled cylindrical shape. The inner roller portion 49 is fixed to the outer surface of the core material 51, and the inner surface of the inner roller portion 49 is in close contact with the outer surface of the core material 51. The pinch roller 46 rotates together with the core material 51.

[0072] The inner roller portion 49 is made of rubber other than silicone rubber. In other words, the entire pinch roller 46 does not have to be made of silicone rubber. For example, the inner roller portion 49 is made of urethane rubber. The silicone tube 50 is made of silicone rubber. The silicone tube 50 is wrapped around the inner roller portion 49. The inner roller portion 49 may also be made of a material other than rubber. For example, the inner roller portion 49 may be made of resin.

[0073] The arithmetic mean roughness Ra of the surface of the silicone tube 50 is 0.1 μm or more and 0.5 μm or less. That is, the arithmetic mean roughness Ra of the surface of the pinch roller 46 is 0.1 μm or more and 0.5 μm or less. In addition, in the above-described modification example 1, the pinch roller 46 may be composed of an inner roller portion 49 and a silicone tube 50. In this case, the silicone tube 50 is made of non-adhesive silicone rubber.

[0074] In this modified example, it becomes possible to prevent adhesive from sticking to the pinch roller 46 regardless of the material of the inner roller portion 49. Furthermore, in this modified example, it becomes possible to prevent adhesive from sticking to the pinch roller 46 by, for example, attaching the silicone tube 50 to the existing pinch roller originally installed in the printing device 1 (specifically, by attaching the silicone tube 50 to the existing pinch roller which is composed of a core material 51 and an inner roller portion 49).

[0075] Furthermore, in the configuration described above, when the entire pinch roller 46 is made of silicone rubber, or in the modified example 1 described above, when the entire pinch roller 46 is made of non-stick silicone rubber, it becomes possible to simplify the structure of the pinch roller 46 compared to the case in this modified example where the pinch roller 46 is made of an inner roller portion 49 made of a different material and a silicone tube 50.

[0076] (Example 3 of changing the pinch roller) Figure 6 is a cross-sectional view illustrating the configuration of a pinch roller 46 according to another embodiment of the present invention. Figure 7 is a diagram illustrating the effect of the pinch roller 46 shown in Figure 6.

[0077] In the above-described embodiment, the outer shape of the pinch roller 46 may be a crown shape in which the outer diameter of the pinch roller 46 decreases from the center to both ends in the axial direction (i.e., left-right direction) of the pinch roller 46. In other words, the pinch roller 46 may be a crown roll. Specifically, the shape of the part of the core material 51 to which the pinch roller 46 is fixed may be a crown shape. As described above, since the pinch roller 46 is formed in a thin-walled cylindrical shape from silicone rubber, in this modified example, when the pinch roller 46 is attached to the outer surface of the core material 51, the outer shape of the pinch roller 46 becomes a crown shape.

[0078] The outer shape of the pinch roller 46 is, for example, a radial crown shape, as shown in Figure 6. That is, the shape of the part of the core material 51 to which the pinch roller 46 is fixed is, for example, a radial crown shape. Alternatively, the outer shape of the pinch roller 46 may be a tapered crown shape. The core material 51 is made of, for example, metal or resin. The width (width in the left-right direction) of the core material 51 is wider than the width of the pinch roller 46. Flanges 51a are formed at both ends of the core material 51 in the left-right direction to prevent the pinch roller 46 from shifting in the left-right direction relative to the core material 51. Also, in the above-described modified examples 1 and 2, the outer shape of the pinch roller 46 may be a crown shape.

[0079] If the pinch roller 46 has a cylindrical shape, as shown in Figure 7, the edge (left-right end) of the pinch roller 46 that contacts the adhesive layer 2 may push the adhesive of the adhesive layer 2 outwards in the left-right direction. Furthermore, if the medium 3 is transported with the adhesive of the adhesive layer 2 pushed outwards in the left-right direction by the edge of the pinch roller 46, the pushed-out portion of the adhesive may remain on the adhesive layer 2 as a roller mark of the pinch roller 46. In this modified example, since the pinch roller 46 has a crown shape, it is possible to prevent the edge of the pinch roller 46 from pushing the adhesive of the adhesive layer 2 outwards in the left-right direction, and as a result, it is possible to prevent the occurrence of roller marks of the pinch roller 46 on the adhesive layer 2.

[0080] (Other embodiments) The embodiments and modifications described above are examples of preferred embodiments of the present invention, but are not limited thereto, and various modifications can be implemented without altering the essence of the invention.

[0081] In the above-described embodiment, the release agent applied to the surface of the pinch roller 46 may be something other than silicone oil. Also, in the above-described embodiment, if the arithmetic mean roughness Ra of the surface of the pinch roller 46, which is made of silicone rubber, is 0.1 μm or more and 0.5 μm or less, then the release agent does not need to be applied to the surface of the pinch roller 46. Furthermore, in the above-described modified example 1, if the pinch roller 46 is made of non-stick silicone rubber, then the release agent does not need to be applied to the surface of the pinch roller 46. Moreover, in the above-described embodiment, if a release agent is applied to the surface of the pinch roller 46, then the arithmetic mean roughness Ra of the surface of the pinch roller 46 may exceed 0.5 μm.

[0082] In the above-described form and modification example 3, the pinch roller 46 may be made of rubber other than silicone rubber. Also, the pinch roller 46 may be made of a material other than rubber. For example, the pinch roller 46 may be made of resin. In these cases, the arithmetic mean roughness Ra of the surface of the pinch roller 46 may exceed 0.5 μm, as long as the adhesive of the adhesive layer 2 does not adhere to the surface of the pinch roller 46. Even in this case, the surface roughness of the pinch roller 46 is determined experimentally to the extent that the adhesive of the adhesive layer 2 does not adhere to the surface of the pinch roller 46, and the surface roughness of the pinch roller 46 is set to the extent that the adhesive of the adhesive layer 2 does not adhere to the surface of the pinch roller 46.

[0083] In the above-described configuration, the printing device 1 does not need to have a media winding unit 15. In this case, for example, a storage box for containing the media 3 after the transfer sheet 4 has been attached is installed below the transfer sheet attachment unit 13. Also, in the above-described configuration, the media 3 may be cut to a predetermined length before being set in the printing device 1. That is, the media 3 does not need to be formed in a long shape. In this case, the media feeding unit 14 and the media winding unit 15 become unnecessary. Also, in this case, the printing device 1 does not need to have a release sheet winding unit 16.

[0084] In the above-described configuration, the transfer sheet application section 13 may be equipped with a pressure roller instead of the after cover 81. In the above-described configuration, it is also possible to install a conveyor belt that contacts the release sheet 6 and transports the medium 3 instead of the drive roller 45 and the pinch roller 46. In this case, an adhesive may be applied to the surface of the conveyor belt that contacts the release sheet 6. [Explanation of Symbols]

[0085] 1 Printing device 2 Adhesive layer 3 Medium 6. Release sheet 11 Printing mechanism 12. Media transport mechanism 13 Transfer sheet application area 18 Ionizer 22 heads (inkjet heads) 45 Drive rollers 46 Pinch Roller 49 Inner roller section 50 Silicone Tubes 82 Heater Y Pinch Roller Axial Dimension

Claims

1. The system comprises a printing mechanism for printing on the adhesive layer of a medium having an adhesive layer and a release sheet disposed on one side of the adhesive layer using an inkjet method, and a medium transport mechanism for transporting the medium. The media transport mechanism comprises a drive roller that contacts the release sheet and a pinch roller that is positioned opposite the drive roller and contacts the adhesive layer. At least the surface of the pinch roller is made of silicone rubber, A printing apparatus characterized in that the arithmetic mean roughness Ra of the surface of the pinch roller is 0.1 μm or more and 0.5 μm or less.

2. The printing apparatus according to claim 1, characterized in that the entire pinch roller is made of silicone rubber.

3. The system comprises a printing mechanism for printing on the adhesive layer of a medium having an adhesive layer and a release sheet disposed on one side of the adhesive layer using an inkjet method, and a medium transport mechanism for transporting the medium. The media transport mechanism comprises a drive roller that contacts the release sheet and a pinch roller that is positioned opposite the drive roller and contacts the adhesive layer. A printing apparatus characterized in that at least the surface of the pinch roller is formed of non-stick silicone rubber.

4. The printing apparatus according to claim 3, characterized in that the entire pinch roller is made of non-adhesive silicone rubber.

5. The printing apparatus according to claim 1 or 3, characterized in that the pinch roller comprises an inner roller portion and a silicone tube whose inner surface is in close contact with the outer surface of the inner roller portion and which constitutes the surface of the pinch roller.

6. The system comprises a printing mechanism for printing on the adhesive layer of a medium having an adhesive layer and a release sheet disposed on one side of the adhesive layer using an inkjet method, and a medium transport mechanism for transporting the medium. The media transport mechanism comprises a drive roller that contacts the release sheet and a pinch roller that is positioned opposite the drive roller and contacts the adhesive layer. A printing apparatus characterized in that a release agent is applied to the surface of the pinch roller.

7. The printing apparatus according to claim 6, characterized in that the mold release agent is silicone oil.

8. The system comprises a printing mechanism for printing on the adhesive layer of a medium having an adhesive layer and a release sheet disposed on one side of the adhesive layer using an inkjet method, and a medium transport mechanism for transporting the medium. The media transport mechanism comprises a drive roller that contacts the release sheet and a pinch roller that is positioned opposite the drive roller and contacts the adhesive layer. The printing apparatus is characterized in that the surface roughness of the pinch roller is set to such a degree that the adhesive of the adhesive layer does not adhere to the surface of the pinch roller.

9. The printing apparatus according to any one of 1 to 4 or any one of 6 to 8, characterized in that the outer shape of the pinch roller is a crown shape in which the outer diameter of the pinch roller decreases from the center of the pinch roller towards both ends in the axial direction of the pinch roller.

10. The printing apparatus according to any one of claims 1 to 4 or any one of claims 6 to 8, characterized in that the printing mechanism comprises an inkjet head for ejecting white ink, an inkjet head for ejecting color ink, and an inkjet head for ejecting clear ink.

11. It is equipped with a transfer sheet attachment section for attaching a transfer sheet to the medium after printing, The printing apparatus according to any one of claims 1 to 4 or any one of claims 6 to 8, characterized in that the transfer sheet attachment section is equipped with a heater for heating the medium after printing.

12. The printing apparatus according to any one of claims 1 to 4 or any one of claims 6 to 8, characterized in that the arithmetic mean roughness Ra of the surface of the pinch roller is 0.4 μm or less.

13. The printing apparatus according to claim 12, characterized in that the arithmetic mean roughness Ra of the surface of the pinch roller is 0.3 μm or less.

14. The printing apparatus according to any one of 1 to 4 or any one of 6 to 8, characterized by comprising an ionizer for removing static electricity from the medium.

15. A maintenance method for a printing apparatus comprising: a printing mechanism for printing on the adhesive layer of a medium having an adhesive layer and a release sheet disposed on one side of the adhesive layer using an inkjet method; and a medium transport mechanism for transporting the medium, wherein the medium transport mechanism comprises a drive roller that contacts the release sheet and a pinch roller that is disposed opposite the drive roller and contacts the adhesive layer, A method for maintaining a printing apparatus, characterized by applying a mold release agent to the surface of the pinch roller during maintenance of the printing apparatus.

Images