Printing cylinder, and image forming apparatus equipped with the printing cylinder.

Abstract

It has high heat resistance while suppressing slippage of the printing media. [Solution] The printing cylinder 21 that transports the printing media 200 has a non-metallic sheet 121 on its outer surface 21a. The non-metallic sheet 121 has a heat resistance temperature of 200°C or higher and a static friction coefficient with the printing media 200 of 0.2 or more and 0.9 or less. The surface roughness of the non-metallic sheet 121 is 0.2 mm or less. The Young's modulus of the non-metallic sheet 121 is 72 GPa or higher. The static friction coefficient of the non-metallic sheet 121 with respect to the printing media 200 is 0.3 or more and 0.8 or less. The thermal conductivity of the non-metallic sheet 121 is less than 2 W / m·K.

Description

Technical Field

[0001] The present invention relates to a printing cylinder and an image forming apparatus including the printing cylinder.

Background Art

[0002] Conventionally, image forming apparatuses that form (print) an image while conveying a printing medium (paper) with a printing cylinder have become widespread. A sheet member is wound around the cylinder body of the printing cylinder of the image forming apparatus without being bent by tension or the like.

[0003] There is a demand for improving the heat insulation, heat resistance, UV (Ultra Violet) resistance, ink resistance, and flexibility of the sheet member. Here, the improvement of "heat insulation" is intended to suppress the influence of the heat of a heater disposed near the printing cylinder. Also, the improvement of "heat resistance" is intended to reduce the influence of heat due to curing light such as UV (Ultraviolet; ultraviolet rays) or the influence of heat from the printing cylinder. Also, the improvement of "UV resistance" is intended to reduce the change in characteristics due to UV. Also, the improvement of "ink resistance" is intended to reduce swelling due to UV ink. Also, the improvement of "flexibility" is intended to make it easier to wind around the cylinder body of the printing cylinder. From these viewpoints, the printing cylinder of an image forming apparatus tends to use a PFA (Perfluoroalkoxy alkane) sheet or a PFAS (Per and Polyfluoroalkyl Substances) sheet as the sheet member. For example, Patent Document 1 discloses a printing cylinder in which a PFA sheet (resin sheet) is wound around a cylinder body as a sheet member, and an image forming apparatus (printer) including the printing cylinder. Here, "PFA" means a copolymer of ethylene tetrafluoride and perfluoroalkoxyethylene. Also, "PFAS" means an organic fluorine compound. Since PFA and PFAS are resistant to heat and chemicals and have the property of repelling water and oil, they have been used in various applications such as household goods such as frying pans, textile products such as clothing, medical devices, products for semiconductor manufacturing, building products, lubricants, and the like.

Prior Art Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-1198 [Overview of the project] [Problems that the invention aims to solve]

[0005] The prior art disclosed in Patent Document 1 can improve the heat resistance of a sheet material. However, the sheet material of the prior art disclosed in Patent Document 1 is a resin sheet (PFA sheet), and therefore has low frictional force. With such prior art disclosed in Patent Document 1, depending on the type of printing media (paper), the printing media may slip, making it difficult to transport the printing media properly.

[0006] The present invention has been made in view of the problems of the prior art described above, and the object of the present invention is to provide a printing cylinder that has high heat resistance and suppresses the occurrence of slippage of the printing medium, and an image forming apparatus equipped with the printing cylinder. [Means for solving the problem]

[0007] The above-mentioned problems of the present invention are solved by the following means.

[0008] (1) A printing cylinder for transporting printing media, wherein the printing cylinder has a heat resistance temperature of 200°C or higher and a non-metallic sheet on its outer surface having a static friction coefficient with the printing media of 0.2 or more and 0.9 or less.

[0009] (2) The printing cylinder described in (1) above, wherein the non-metallic sheet has a surface roughness of 0.2 mm or less.

[0010] (3) The printing cylinder according to (1) above, wherein the Young's modulus of the nonmetallic sheet is 72 GPa or more.

[0011] (4) The printing cylinder according to (1) above, wherein the static friction coefficient of the non-metallic sheet with respect to the printing medium is 0.3 or more and 0.8 or less.

[0012] (5) The printing cylinder described in (1) above, wherein the thermal conductivity of the nonmetallic sheet is less than 2 W / m·K.

[0013] (6) The printing cylinder as described in (1) above, wherein the non-metallic sheet is based on a material whose main component is one or more raw materials selected from cellulose, glass, carbon, calcium, and ceramic.

[0014] (7) The printing cylinder described in (1) above, wherein the non-metallic sheet is based on a paper sheet made of cellulose.

[0015] (8) The printing cylinder described in (7) above, wherein the paper sheet is made up of multiple sheets stacked on top of each other.

[0016] (9) The printing cylinder according to (1) above, wherein the nonmetallic sheet has a heat resistance temperature of 260°C or higher and is composed of a non-organic fluorine compound.

[0017] (10) The printing cylinder according to (1) above, wherein the nonmetallic sheet has a heat resistance temperature of 300°C or higher and is composed of a non-organic fluorine compound.

[0018] (11) The printing cylinder according to (1) above, wherein the non-metallic sheet is breathable in a direction perpendicular to the tangent line in contact with the printing cylinder.

[0019] (12) The printing cylinder according to (11), wherein the ventilation is ensured by through holes formed perpendicular to the tangent line in contact with the printing cylinder.

[0020] (13) The printing cylinder as described in (12) above, wherein the through hole has a shape without corners.

[0021] (14) The printing cylinder according to (13) above, wherein the through hole has an elongated elliptical shape along the transport direction.

[0022] (15) The through holes are arranged in a staggered pattern, and the printing cylinder according to (13) above.

[0023] (16) The non-metal sheet is wound around the cylinder body of the printing cylinder, and the method of winding the non-metal sheet around the cylinder body is a method selected from at least one of pulling winding and adhesive pasting, and the printing cylinder according to (1) above.

[0024] (17) The adhesive member used for winding is attached to the non-metal sheet side, and the printing cylinder according to (16) above.

[0025] (18) The adhesive member used for winding has air permeability in a direction perpendicular to the tangent line in contact with the printing cylinder, and the printing cylinder according to (16) above.

[0026] (19) The paper sheet which is the base material of the non-metal sheet is a paper sheet selected from one or more of a member with a flame-retardant function, a member with a moisture-proof function, a member with an antistatic function, a dust-free paper, and a paper sheet with a coated surface, and the printing cylinder according to (7) above.

[0027] (20) The coating on the surface of the paper sheet is one or more of a flame-retardant coating, a water-repellent coating, an antistatic coating, and a dust-proof coating, and the printing cylinder according to (19) above.

[0028] (21) An image forming apparatus having a printing cylinder for conveying a printing medium and an image forming unit for forming an image on the printing medium conveyed by the printing cylinder, wherein the printing cylinder has a non-metal sheet on its outer peripheral surface with a heat-resistant temperature of 200 °C or higher and a static friction coefficient with the printing medium of 0.2 or higher and 0.9 or lower.

[0029] (22) The thermal conductivity of the non-metal sheet is set to be less than 2 W / m·K, and the image forming apparatus according to (21) above.

[0030] (23) The image forming apparatus described in (21) above, configured as an inkjet printer capable of sheet-fed printing and double-sided printing.

[0031] (24) The image forming apparatus according to (21), wherein the image forming unit has an ink ejection unit, the ejection unit uses UV ink that is UV light cured on the printing medium held by the printing cylinder as the ink, and ejects the UV ink at a temperature higher than the temperature of the printing medium.

[0032] (25) The image forming apparatus according to (21) above, wherein the nonmetallic sheet is based on a paper sheet made of cellulose, and the thickness of the paper sheet which is the base material of the nonmetallic sheet is 0.08 mm to 10 mm.

[0033] (26) The image forming apparatus according to (21) above, wherein the nonmetallic sheet is composed of a non-organofluorine compound.

[0034] (27) The image forming apparatus according to (21) above, wherein the nonmetallic sheet is mainly composed of one or more raw materials selected from cellulose, glass, carbon, calcium, and ceramic.

[0035] (28) The image forming apparatus according to (21) above, wherein the non-metallic sheet is based on a paper sheet made of cellulose. [Effects of the Invention]

[0036] According to the present invention, it is possible to suppress the occurrence of slippage in the printing media while maintaining high heat resistance. [Brief explanation of the drawing]

[0037] [Figure 1] This is a schematic diagram of the entire image forming apparatus according to the embodiment. [Figure 2] This is a block diagram of the main functions of the image forming apparatus according to the embodiment. [Figure 3]This is an explanatory diagram illustrating the main properties of the non-metallic sheet used on the outer surface of the printing cylinder. [Figure 4] This is an explanatory diagram illustrating an example of the composition of a non-metallic sheet. [Figure 5] This is a diagram illustrating the configuration and operation of the printing cylinder during the transport of printing media. [Figure 6A] This is an external view of a non-metallic sheet. [Figure 6B] This is a close-up view of a non-metallic sheet. [Figure 7] This is an explanatory diagram of the first method for attaching a non-metallic sheet to the printing cylinder. [Figure 8A] This is an explanatory diagram of a second method for attaching a non-metallic sheet to the printing cylinder. [Figure 8B] This is a partial cross-sectional view of a non-metallic sheet used in the second mounting method. [Modes for carrying out the invention]

[0038] Embodiments of the present invention will be described in detail below with reference to the drawings. Note that the drawings are merely schematic representations to allow for a thorough understanding of the present invention. Therefore, the present invention is not limited to the illustrated examples. Furthermore, in each drawing, common or similar components are denoted by the same reference numerals, and their redundant descriptions are omitted.

[0039] <Configuration of an image forming apparatus> The configuration of the inkjet printing apparatus 100, as an example of an image forming apparatus according to this embodiment, will be described below with reference to Figures 1 and 2. Figure 1 is a schematic diagram of the overall configuration of the inkjet printing apparatus 100 according to this embodiment. Figure 2 is a block diagram of the main functions of the inkjet printing apparatus 100.

[0040] (Overall configuration of the image forming apparatus) In this embodiment, an inkjet printing apparatus 100 that employs a filling-type inert gas supply method will be described as an example of an image forming apparatus. Here, "filling-type" refers to an inert gas supply method in which the space between the irradiation unit, which irradiates with active rays such as ultraviolet light, and the transport surface is filled with inert gas, and the printing media (recording medium) is then introduced into it. Note that the ink used in the inkjet printing apparatus 100 is not limited to ultraviolet-curable ink. For example, ink that hardens with active rays of any wavelength, such as visible light, infrared light, or gamma rays, may be used. Furthermore, the irradiation unit of the inkjet printing apparatus 100 will irradiate with active rays of a wavelength that hardens the ink used.

[0041] As shown in Figure 1, the inkjet printing apparatus 100 according to this embodiment includes a paper feeding unit 10, an image recording unit 20, a paper discharge unit 30, and a control unit 90. Under the control of the control unit 90, the inkjet printing apparatus 100 transports the printing media 200 stored in the paper feeding unit 10 to the image recording unit 20, records an image on the printing media 200 in the image recording unit 20, and transports the printed media 200 with the recorded image to the paper discharge unit 30.

[0042] As the printing medium 200, various media can be used, such as plain paper or coated paper, as well as fabrics or sheet-like resins, that can solidify the ink dispensed onto the surface. In this embodiment, the case in which paper is used as the printing medium 200 will be described. Hereinafter, the printing medium 200 may be referred to as "paper".

[0043] The paper feeding unit 10 is a mechanism that supplies printing media 200 to the image recording unit 20. The paper feeding unit 10 includes a paper feeding tray 11 for storing the printing media 200 and a media supply unit 12 for supplying the printing media 200 from the paper feeding tray 11 to the image recording unit 20. In this embodiment, the media supply unit 12 is described as having a ring-shaped belt stretched over two rollers, and transporting the printing media 200 by rotating the rollers with the printing media 200 placed on the belt.

[0044] The image recording unit 20 is a mechanism for recording images on the printing medium 200. The image recording unit 20 includes a printing cylinder 21, a transfer drum 22, an inkjet head unit 24, an active ray irradiation unit 25, a separation unit 26, and a paper reversal unit 28.

[0045] The printing cylinder 21 is a component that transports the printing media 200. The printing cylinder 21 has a drum-type (cylindrical) shape. Hereinafter, the printing cylinder 21 may be referred to as the "transport drum". The printing cylinder 21 has an outer peripheral surface 21a that functions as a transport surface for the printing media 200, and a plurality of holes (not shown) are formed on this outer peripheral surface 21a. The printing cylinder 21 holds the printing media 200 on the outer peripheral surface 21a by drawing ambient gas from the outside to the inside of the outer peripheral surface 21a. The printing cylinder 21 has a rotation axis (not shown) that is arranged to extend in the width direction (the direction perpendicular to the paper plane in Figure 1), and rotates around this rotation axis while holding the printing media 200 on the outer peripheral surface 21a. The printing cylinder 21 is connected to a motor (not shown) for rotating the printing cylinder 21, and rotates by an angle proportional to the amount of rotation of the motor. As a result, the printing cylinder 21 transports the printing media 200 in the transport direction along the outer peripheral surface 21a. A non-metallic sheet 121 is placed on the outer circumferential surface 21a of the printing cylinder 21. The non-metallic sheet 121 is a component that has high heat resistance while suppressing the occurrence of slippage of the printing media 200. Details of the non-metallic sheet 121 will be described later.

[0046] The transfer drum 22 is a rotating body that transfers the printing media 200, which has been transported by the media supply unit 12 of the paper feeding unit 10, to the printing cylinder 21. The transfer drum 22 is located between the media supply unit 12 of the paper feeding unit 10 and the printing cylinder 21. A plurality of rollers 22a (three in the example shown in Figure 1) and a heater 301 are provided around the transfer drum 22. The plurality of rollers 22a form nips (clamping parts) with the transfer drum 22 and are components that rotate with the rotation of the transfer drum 22 to transport the printing media 200. The heater 301 is a component that heats the transfer drum 22. The heater 301 operates under the control of the control unit 90 and radiates heat to preheat the transfer drum 22. As a result, the inkjet printing apparatus 100 preheats the transfer drum 22 and, consequently, the printing media 200 to a predetermined temperature prior to the image formation process.

[0047] The inkjet head unit 24 is an image forming unit that ejects ink onto the printing media 200 to form (print) an image. Based on a print command from an external device (not shown), the inkjet head unit 24 ejects ink onto the printing media 200 held by the printing cylinder 21 at an appropriate timing corresponding to the rotation of the printing cylinder 21. As a result, the inkjet printing apparatus 100 forms (prints) an image on the printing media 200. In this embodiment, the inkjet head unit 24 has four inkjet heads 24Y, 24M, 24C, and 24K, each corresponding to one of four ink colors: yellow (Y), magenta (M), cyan (C), and black (K). The four inkjet heads 24Y, 24M, 24C, and 24K are arranged facing each other on the outer circumferential surface 21a of the printing cylinder 21, so as to be arranged at predetermined intervals from the upstream side in the transport direction of the printing media 200.

[0048] The active ray irradiation unit 25 is a light-emitting unit arranged opposite to the printing cylinder 21 in the width direction. The active ray irradiation unit 25 irradiates the printing media 200 placed on the outer peripheral surface 21a of the printing cylinder 21 with an active ray such as ultraviolet light to cure and fix the ink ejected onto the printing media 200.

[0049] The separation unit 26 is a mechanism that separates the printing media 200 from the printing cylinder 21 and sends it to the paper discharge unit 30. The separation unit 26 is located downstream of the active ray irradiation unit 25. In this embodiment, the separation unit 26 will be described as having a configuration comprising transport rollers 26a, 26b, and 26c, and a belt transport unit 27. The transport roller 26a is a roller positioned opposite the printing cylinder 21. The transport roller 26b is a roller positioned opposite the transport roller 26a. The transport roller 26c is a roller positioned opposite the transport roller 26b. The belt transport unit 27 is a belt positioned opposite the transport roller 26c. The inkjet printing apparatus 100 separates the printing media 200 from the outer circumferential surface 21a of the printing cylinder 21 and transports the printing media 200 to the paper discharge unit 30 by driving the transport rollers 26a, 26b, and 26c and the belt transport unit 27.

[0050] The paper reversal unit 28 is a mechanism for reversing the front and back sides of the printing media 200. The paper reversal unit 28 is located downstream of the separation unit 26. In this embodiment, the paper reversal unit 28 will be described as having a transport roller 28a. The transport roller 28a is a roller positioned opposite the transport roller 26b of the separation unit 26. The paper reversal unit 28 receives the printing media 200 from the transport roller 26b of the separation unit 26 to the transport roller 28a and returns the printing media 200 to the printing cylinder 21. In this way, the paper reversal unit 28 reverses the front and back sides of the printing media 200.

[0051] The inkjet printing apparatus 100 has a heater 302 and a fan 303 in the space between the transport roller 26b and the printing cylinder 21.

[0052] The heater 302 operates under the control of the control unit 90 and radiates heat to warm the printing cylinder 21. As a result, the inkjet printing apparatus 100 warms the printing cylinder 21 and, consequently, the printing media 200 to a predetermined temperature prior to the image formation process.

[0053] Meanwhile, the fan 303 operates under the control of the control unit 90, blowing cooling air onto the printing cylinder 21. This allows the inkjet printing apparatus 100 to adjust the printing cylinder 21 and, consequently, the printing media 200, to a predetermined temperature prior to the image formation process.

[0054] The paper output unit 30 has a plate-shaped paper output tray 31 on which the printing media 200 sent out from the image recording unit 20 by the separation unit 26 is placed.

[0055] (Main functional configuration of an image forming apparatus) As shown in Figure 2, the inkjet printer 100 comprises a data input unit 91, a head drive unit 92, and a control unit 90. The data input unit 91 is a component into which various data related to the print job is input and stored. The head drive unit 92 is a component that drives the inkjet heads 24Y, 24M, 24C, and 24K. The inkjet heads 24Y, 24M, 24C, and 24K are ejection units that eject ink. The control unit 90 is a component that controls the operation of the entire inkjet printer 100. The control unit 90 controls the operation of the data input unit 91, the head drive unit 92, the active ray irradiation unit 25, etc. The control unit 90 also controls the operation of the paper feed unit 10, the inert gas supply unit 40, the suction unit 50, the paper reversal unit 28, the paper discharge unit 30, etc. The inert gas supply unit 40 is a component that supplies and fills the space between the active ray irradiation unit 25 and the printing media 200 with an inert gas such as nitrogen. The suction unit 50 is a component that generates negative pressure to attract the printing media 200 to the outer peripheral surface 21a of the printing cylinder 21.

[0056] (Main properties of non-metallic sheets) The main characteristics of the non-metallic sheet 121 used on the outer surface 21a of the printing cylinder 21 will be explained below with reference to Figure 3. Figure 3 is an explanatory diagram of the main characteristics of the non-metallic sheet 121 used on the outer surface 21a of the printing cylinder 21.

[0057] As shown in Figure 3, the non-metallic sheet 121 has a heat resistance temperature of 200°C or higher and a static friction coefficient with the printing media 200 of 0.2 or higher and 0.9 or lower. Such a printing cylinder 21 can have high heat resistance while suppressing the occurrence of slippage of the printing media 200.

[0058] In particular, the static friction coefficient of the non-metallic sheet 121 should be between 0.3 and 0.8. Such a printing cylinder 21 has a low static friction coefficient of 0.3 or 0.8 for the non-metallic sheet 121. Therefore, the printing cylinder 21 can have high heat resistance while also suppressing the occurrence of slippage of the printing media 200.

[0059] Furthermore, the non-metallic sheet 121 has a surface roughness of 0.2 mm or less on the surface that contacts the printing media 200. This surface roughness is the surface roughness of the non-metallic sheet 121 excluding the through holes 131a and 131b (Figure 5) described later. This surface roughness may also be the difference in height of the embossing (recesses) formed on the non-metallic sheet 121. Since such a printing cylinder 21 has a smooth surface with a surface roughness of 0.2 mm or less on the surface that contacts the printing media 200, good print quality can be ensured.

[0060] Furthermore, the Young's modulus of the non-metallic sheet 121 is 72 GPa or higher. The Young's modulus is an indicator of how easily it can be wrapped around the outer surface 21a of the printing cylinder 21. Because such a printing cylinder 21 has a high Young's modulus of 72 GPa or higher, the non-metallic sheet 121 can be well wrapped around the outer surface 21a of the printing cylinder 21.

[0061] Furthermore, the thermal conductivity of the non-metallic sheet 121 is less than 2 W / m·K. Such a printing cylinder 21 has a thermal conductivity less than 2 W / m·K. Therefore, the printing cylinder 21 can be made less permeable to heat (i.e., its heat transfer is suppressed). Such a printing cylinder 21 can prevent the printing media 200 from sticking to the printing cylinder 21 and the heat from becoming trapped inside the printing cylinder 21, especially when the image forming apparatus performs double-sided printing, due to the printing cylinder 21 becoming hot.

[0062] (Example of non-metallic sheet configuration) The following describes an example of the configuration of the non-metallic sheet 121 with reference to Figure 4. Figure 4 is an explanatory diagram of an example of the configuration of the non-metallic sheet 121.

[0063] As shown in Figure 4, the non-metallic sheet 121 of the printing cylinder 21 can be based on a material whose main component is one or more raw materials selected from cellulose, glass, carbon, calcium, and ceramic. Such a printing cylinder 21 can have high heat resistance while suppressing the occurrence of slippage of the printing media 200.

[0064] Furthermore, the non-metallic sheet 121 of the printing cylinder 21 can be made from, for example, a paper sheet composed of cellulose. By using a paper material (paper sheet) as the base material for the non-metallic sheet 121 of such a printing cylinder 21, both environmental friendliness and heat resistance can be achieved. In addition, the printing cylinder 21 can obtain suitable strength, wrinkle resistance, heat insulation, and poroforming properties.

[0065] Furthermore, the non-metallic sheet 121 of the printing cylinder 21 can have a heat resistance temperature of 260°C or higher and be made of a non-organic fluorine compound. Such a printing cylinder 21 can withstand use in high-temperature locations near the heater 302.

[0066] Furthermore, the non-metallic sheet 121 of the printing cylinder 21 can be made of a non-organic fluorine compound, for example, with a heat resistance temperature of 300°C or higher. Such a printing cylinder 21 can withstand use in locations where the temperature near the heater 302 becomes 300°C or higher.

[0067] (Print cylinder configuration and operation) The detailed configuration and operation of the printing cylinder 21 of the inkjet printing apparatus 100 will be described below with reference to Figure 5. Figure 5 is an explanatory diagram of the configuration and operation of the printing cylinder 21 when the printing media 200 is being transported.

[0068] In the example shown in Figure 5, the printing cylinder 21 has a cylinder body 41 located in the center, a plurality of (two in the illustrated example) paper sheets 122a, 122b located on the outer surface 21a, and a vacuum device (not shown) located in the internal space of the cylinder body 41.

[0069] The main body 41 is a roughly cylindrical metal part. Multiple through holes 41a are provided near the outer circumferential surface 21a of the main body 41. The diameter of the through holes 41a is, for example, 1 mm.

[0070] In this embodiment, a paper sheet 122a, which is roughly rectangular in plan view, is applied to the outer circumference of the main body 41. The paper sheet 122a has a plurality of through holes 131a. The diameter of the through holes 131a is preferably, for example, 0.2 mm or more and 1 mm or less, and more preferably, 0.3 mm or more and 0.9 mm or less. The thickness of the paper sheet 122a is, for example, 0.1 mm.

[0071] Furthermore, a roughly rectangular paper sheet 122b is placed around the outer periphery of the paper sheet 122a. The paper sheet 122b has multiple through holes 131b. The diameter of the through holes 131b is preferably, for example, 0.2 mm or more and 1 mm or less, and more preferably 0.3 mm or more and 0.9 mm or less.

[0072] The through-holes 41a in the cylinder body 41, 131a in the paper sheet 122a, and 131b in the paper sheet 122b function as air intake holes. Hereinafter, the through-holes 131a and 131b will be collectively referred to as "through-hole 131". When transporting the printing media 200, the inkjet printing device 100 operates a vacuum device (not shown) to create a vacuum (i.e., suck air) towards the inside of the printing cylinder 21 through the through-holes 41a, 131a, and 131b. As a result, the inkjet printing device 100 holds the printing media 200 by suction to the outer surface 21a of the printing cylinder 21 and transports the printing media 200 from the transfer drum 22 to the separation unit 26 (or the paper reversal unit 28).

[0073] Multiple paper sheets 122a, 122b constitute a non-metallic sheet 121. Furthermore, the multiple paper sheets 122a, 122b function as thermal insulation. The multiple paper sheets 122a, 122b are placed in a predetermined area in the circumferential direction of the outer surface 21a of the printing cylinder 21. As shown in Figure 1, in this embodiment, three non-metallic sheets 121 of the same shape are arranged in positions with 120° rotational symmetry when viewed along the axial direction of the cylinder body 41. All three non-metallic sheets 121 are placed on the outer surface 21a of the portion defined by the cylinder body 41. The printing media 200 is transported by the printing cylinder 21 while resting on the non-metallic sheets 121.

[0074] In the inkjet printing apparatus 100, the outer surface 21a of the printing cylinder 21 is cooled due to convection caused by the heat generated by the heater 302 and convection caused by the vacuuming performed by a vacuum device (not shown). As a result, temperature unevenness may occur on the outer surface 21a of the printing cylinder 21 in the inkjet printing apparatus 100. However, the inkjet printing apparatus 100 has a non-metallic sheet 121 that functions as an insulating material on the outer surface 21a of the printing cylinder 21. With such an inkjet printing apparatus 100, temperature unevenness on the outer surface 21a of the printing cylinder 21 can be suppressed by the non-metallic sheet 121. As a result, the inkjet printing apparatus 100 can improve print quality.

[0075] Furthermore, the non-metallic sheet 121 of the printing cylinder 21 is made up of multiple superimposed paper sheets 121a and 121b. By using multiple superimposed paper sheets 121a and 121b, such a printing cylinder 21 can achieve both environmental friendliness and heat resistance.

[0076] Furthermore, the non-metallic sheet 121 of the printing cylinder 21 is permeable in a direction substantially perpendicular to the tangent line that contacts the printing cylinder 21. In the printing cylinder 21, the permeability of the non-metallic sheet 121 is ensured by through holes 41a, 131a, and 131b formed substantially perpendicular to the tangent line that contacts the printing cylinder 21. Here, "having permeability" means having holes or being formed of a porous material. In other words, the non-metallic sheet 121 is made of a material with holes or a porous material. Since the non-metallic sheet 121 must not peel off, it is wrapped straight around the cylinder body 41 of the printing cylinder 21 in a direction substantially perpendicular to it. Such a printing cylinder 21 can ensure permeability between the inside and outside.

[0077] (Composition of non-metallic sheets) The structure of the non-metallic sheet 121 will be described below with reference to Figures 6A and 6B. Figure 6A is an external view of the non-metallic sheet 121. Figure 6B is a partially enlarged view of the non-metallic sheet 121, showing an enlarged view of the region 401 shown in Figure 6A.

[0078] As shown in Figure 6B, the printing cylinder 21 has three non-metallic sheets 121 (paper sheets 122a, 122b) of the same shape, positioned at 120° rotationally symmetrical positions when viewed along the axial direction of the cylinder body 41 (Figure 5).

[0079] As shown in Figure 6B, in the printing cylinder 21, the through holes 131 (through holes 131a and 131b shown in Figure 5) of the non-metallic sheet 121 (paper sheets 122a and 122b) have a shape without corners. Although not shown, the through hole 41a of the cylinder body 41 of the printing cylinder 21 also has a shape without corners. Such a printing cylinder 21 can prevent damage and deterioration due to stress concentration at corners.

[0080] Furthermore, in the printing cylinder 21, the through-holes 131 of the non-metallic sheet 121 have an elongated elliptical shape along the conveying direction. Although not shown in the figures, the through-holes 41a of the cylinder body 41 of the printing cylinder 21 also have an elongated elliptical shape along the conveying direction. Such a printing cylinder 21 can avoid tension and stress concentration during winding and tensioning of the non-metallic sheet 121.

[0081] Furthermore, in the printing cylinder 21, the through holes 131 of the non-metallic sheet 121 are arranged in a staggered pattern. Although not shown in the figures, the through holes 41a of the cylinder body 41 of the printing cylinder 21 are also arranged in a staggered pattern. Such a printing cylinder 21 can evenly adsorb the printing media 200. In addition, the printing cylinder 21 can improve the opening ratio of the through holes 131. Furthermore, by not arranging the through holes 131 in a single line, the strength of the non-metallic sheet 121 can be improved.

[0082] (Method for attaching non-metallic sheets to the printing cylinder) The non-metallic sheet 121 can be attached to the printing cylinder 21 using the first attachment method shown in Figure 7, or the second attachment method shown in Figures 8A and 8B.

[0083] First, the first mounting method will be explained with reference to Figure 7. Figure 7 is an explanatory diagram of the first mounting method of the non-metallic sheet 121 to the printing cylinder 21.

[0084] In the first mounting method shown in Figure 7, the non-metallic sheet 121 is wrapped around the cylinder body 41 of the printing cylinder 21. In the first mounting method shown in Figure 7, the non-metallic sheet 121 supplied from the sheet supply unit 190 is wrapped around the cylinder body 41 of the printing cylinder 21 by tension wrapping. With the non-metallic sheet 121 attached using the first mounting method, the printing cylinder 21 can make the non-metallic sheet 121 (paper sheets 122a, 122b) adhere tightly to the printing cylinder 21. Therefore, the printing cylinder 21 can suppress the occurrence of wrinkles in the non-metallic sheet 121.

[0085] Next, the second mounting method will be described with reference to Figures 8A and 8B. Figure 8A is an explanatory diagram of the second mounting method of the non-metallic sheet 121 to the printing cylinder 21. Figure 8B is a partial cross-sectional view of the non-metallic sheet 121 used in the second mounting method, showing an enlarged view of the region 402 shown in Figure 8A.

[0086] In the second mounting method shown in Figures 8A and 8B, the non-metallic sheet 121 is also wrapped around the cylinder body 41 of the printing cylinder 21. In the second mounting method shown in Figures 8A and 8B, the non-metallic sheet 121 (paper sheet 122a, 122b), which has an adhesive member 140 (Figure 8B) attached to its back surface, is attached to the cylinder body 41 of the printing cylinder 21 by adhesive attachment. With this type of printing cylinder 21, the non-metallic sheet 121 can be tightly attached to the printing cylinder 21. Therefore, the printing cylinder 21 can suppress the occurrence of wrinkles in the non-metallic sheet 121. Furthermore, since the non-metallic sheet 121 is attached to the cylinder body 41 by adhesive attachment, the printing cylinder 21 can easily replace the non-metallic sheet 121 by peeling it off the cylinder body 41. Note that the method of attaching the non-metallic sheet is not limited to what is shown in the figures, and includes, for example, attaching a single-sheet-shaped non-metallic sheet.

[0087] As shown in Figure 8B, in the printing cylinder 21, the adhesive member 140 used for wrapping is attached to the non-metallic sheet 121 side. With such a printing cylinder 21, the thin non-metallic sheet 121 can be attached to the printing cylinder 21 by the adhesive member 140 attached to the thin non-metallic sheet 121 side.

[0088] Furthermore, in the printing cylinder 21, the adhesive member 140 used for wrapping should preferably have breathability in a direction substantially perpendicular to the tangent line in contact with the printing cylinder 21. Such a printing cylinder 21 can ensure breathability between the inside and outside.

[0089] Furthermore, in the printing cylinder 21, the paper sheets 122a and 122b, which are the base materials of the non-metallic sheet 121, may be materials to which flame retardant functionality has been added, for example, by impregnating them with a flame retardant. Such a printing cylinder 21 can have a higher heat resistance temperature.

[0090] Furthermore, the printing cylinder 21 may be a component that has added moisture-preventing properties, for example, by applying a coating material. Such a printing cylinder 21 can improve water resistance. Therefore, the printing cylinder 21 can, for example, keep the size of the paper sheets 122a and 122b constant, thereby suppressing the formation of wrinkles in the paper sheets 122a and 122b. Such a printing cylinder 21 can improve (or maintain) print quality.

[0091] Furthermore, in the printing cylinder 21, the paper sheets 122a and 122b, which are the base materials of the non-metallic sheet 121, may be materials to which an antistatic function has been added, for example, by incorporating conductive fibers. Such a printing cylinder 21 can be configured to have an antistatic function. Therefore, the printing cylinder 21 can prevent electrostatic adhesion of the paper sheets 122a and 122b, and can suppress the formation of wrinkles in the paper sheets 122a and 122b. Such a printing cylinder 21 can improve (or maintain) the print quality.

[0092] Furthermore, in the printing cylinder 21, the paper sheets 122a and 122b, which are the base material of the non-metallic sheet 121, are preferably dust-free paper manufactured by impregnating the paper sheets 122a and 122b with a small amount of resin, for example. In such a printing cylinder 21, because the paper sheets 122a and 122b are dust-free paper, it is possible to suppress the deterioration of transport quality and printing quality caused by clogging of the through holes 131a and 131b (through hole 131).

[0093] Furthermore, in the printing cylinder 21, the paper sheets 122a and 122b, which are the base materials for the non-metallic sheet 121, may have their surfaces coated. Such a printing cylinder 21 can impart any desired properties to the paper sheets 122a and 122b through coating.

[0094] Furthermore, in the printing cylinder 21, the coating applied to the surface of the paper sheets 122a and 122b may be one or more types of coatings from among flame-retardant coatings, water-repellent coatings, antistatic coatings, and dustproof coatings. Such a printing cylinder 21 can impart properties such as flame retardancy, water repellency, antistatic properties, and dustproof properties to the paper sheets 122a and 122b through the coating.

[0095] <Main features of the printing cylinder and image forming apparatus> The printing cylinder 21 and the image forming apparatus (inkjet printing apparatus 100) according to this embodiment can be configured to have the following features.

[0096] (1) The printing cylinder 21 according to this embodiment is a component that transports the printing media 200. As shown in Figure 1, the printing cylinder 21 has a non-metallic sheet 121 on its outer surface 21a. As shown in Figure 3, the non-metallic sheet 121 has a heat resistance temperature of 200°C or higher and a static friction coefficient with the printing media 200 of 0.2 or more and 0.9 or less. The printing cylinder 21 according to this embodiment has high heat resistance and can suppress the occurrence of slippage of the printing media 200. Therefore, the printing cylinder 21 can withstand use in high-temperature locations near the heater 302. In addition, the printing cylinder 21 can suppress the occurrence of slippage of the printing media 200 and transport the printing media 200 well, thereby ensuring good print quality.

[0097] (2) As shown in Figure 3, in the printing cylinder 21 of item (1) above, the non-metallic sheet 121 has a surface roughness of 0.2 mm or less. The printing cylinder 21 according to this embodiment can transport the printing media 200 well, and thus can ensure good print quality.

[0098] (3) As shown in Figure 3, in the printing cylinder 21 of item (1) above, the Young's modulus of the nonmetallic sheet 121 is preferably 72 GPa or higher. The Young's modulus represents the value when wrapped around the outer surface 21a of the printing cylinder 21. In the printing cylinder 21 of this embodiment, the Young's modulus of the nonmetallic sheet 121 is a high value of 72 GPa or higher. Therefore, the printing cylinder 21 can wrap the nonmetallic sheet 121 well around the outer surface 21a of the printing cylinder 21.

[0099] (4) As shown in Figure 3, in the printing cylinder 21 of item (1) above, the static friction coefficient of the non-metallic sheet 121 with respect to the printing media 200 is preferably 0.3 or more and 0.8 or less. The printing cylinder 21 according to this embodiment has high heat resistance and can further suppress the occurrence of slippage of the printing media 200.

[0100] (5) As shown in Figure 3, in the printing cylinder 21 of item (1) above, the thermal conductivity of the nonmetallic sheet 121 is preferably less than 2 W / m·K. The printing cylinder 21 according to this embodiment can be made less permeable to heat (i.e., heat transfer is suppressed). In particular when the image forming apparatus performs double-sided printing, such a printing cylinder 21 can prevent the printing medium 200 from sticking to the printing cylinder 21 due to the printing cylinder 21 becoming hot and heat from becoming trapped inside the printing cylinder 21.

[0101] (6) As shown in Figure 4, in the printing cylinder 21 of item (1) above, the non-metallic sheet 121 can be based on a material whose main component is one or more raw materials selected from cellulose, glass, carbon, calcium, and ceramic. Such a printing cylinder 21 according to this embodiment can have high heat resistance while suppressing the occurrence of slippage of the printing media 200.

[0102] (7) As shown in Figure 4, in the printing cylinder 21 of item (1) above, the non-metallic sheet 121 can be made from a paper sheet composed of cellulose. In this embodiment of the printing cylinder 21, by using a paper material (paper sheet) as the base material for the non-metallic sheet 121, both environmental friendliness and heat resistance can be achieved. Furthermore, the printing cylinder 21 can obtain suitable strength, wrinkle resistance, heat insulation, and poroforming properties.

[0103] (8) As shown in Figure 5, in the printing cylinder 21 of item (7) above, the paper sheet is made up of multiple sheets stacked on top of each other. By using a paper sheet made of multiple sheets stacked on top of each other, the printing cylinder 21 of this embodiment can achieve both environmental friendliness and heat resistance.

[0104] (9) As shown in Figure 4, in the printing cylinder 21 of item (1) above, the non-metallic sheet 121 can be made of a non-organofluorine compound with a heat resistance temperature of 260°C or higher. The printing cylinder 21 according to this embodiment can withstand use in high-temperature locations near the heater 302.

[0105] (10) As shown in Figure 4, in the printing cylinder 21 of item (1) above, the non-metallic sheet 121 can be made of a non-organofluorine compound with a heat resistance temperature of 300°C or higher. The printing cylinder 21 according to this embodiment can withstand use in places where the temperature near the heater 302 becomes high, such as 300°C or higher.

[0106] (11) As shown in Figure 5, in the printing cylinder 21 of item (1) above, the non-metallic sheet 121 has breathability in a direction substantially perpendicular to the tangent line that is in contact with the printing cylinder 21. The printing cylinder 21 according to this embodiment can ensure breathability between the inside and the outside.

[0107] (12) As shown in Figure 5, in the printing cylinder 21 of item (11) above, ventilation is ensured by through holes 41a, 131a, and 131b formed substantially perpendicular to the tangent line in contact with the printing cylinder 21. In this embodiment of the printing cylinder 21, ventilation can be ensured between the inside and the outside.

[0108] (13) As shown in Figure 6B, in the printing cylinder 21 of item (12) above, the through holes 131 (through holes 131a and 131b shown in Figure 5) have a shape without corners. The printing cylinder 21 according to this embodiment can prevent damage and deterioration due to stress concentration at corners.

[0109] (14) As shown in Figure 6B, in the printing cylinder 21 of item (13) above, the through holes 131 (through holes 131a and 131b shown in Figure 5) have an elongated elliptical shape along the transport direction. The printing cylinder 21 according to this embodiment can avoid tension and stress concentration when winding the non-metallic sheet 121 or when tensioning it.

[0110] (15) As shown in Figure 6B, in the printing cylinder 21 of item (13) above, the through holes 131 (through holes 131a, 131b shown in Figure 5) are arranged in a staggered pattern. The printing cylinder 21 according to this embodiment can evenly adsorb the printing media 200. The printing cylinder 21 can also improve the opening ratio of the through holes 131. Furthermore, by not arranging the through holes 131 in a single line, the strength of the non-metallic sheet 121 can be improved.

[0111] (16) As shown in Figure 7, in the printing cylinder 21 of item (1) above, the non-metallic sheet 121 is wrapped around the cylinder body 41 of the printing cylinder 21, and the method of wrapping the non-metallic sheet 121 around the cylinder body 41 is a method selected from at least one of tension wrapping and adhesive attachment.

[0112] When the non-metallic sheet 121 is wound using a tension winding method, the printing cylinder 21 according to this embodiment can make the non-metallic sheet 121 (paper sheets 122a, 122b) adhere tightly to the printing cylinder 21. Therefore, the printing cylinder 21 can suppress the occurrence of wrinkles in the non-metallic sheet 121.

[0113] Furthermore, when the non-metallic sheet 121 is wrapped using an adhesive method, the printing cylinder 21 according to this embodiment can tightly adhere the non-metallic sheet 121 (paper sheets 122a, 122b) to the printing cylinder 21. Therefore, the printing cylinder 21 can suppress the occurrence of wrinkles in the non-metallic sheet 121. Moreover, the printing cylinder 21 is attached to the cylinder body 41 by wrapping the non-metallic sheet 121 around it using adhesive. Therefore, the printing cylinder 21 can easily replace the non-metallic sheet 121 by peeling it off the cylinder body 41.

[0114] (17) As shown in Figure 8B, in the printing cylinder 21 of item (16) above, the adhesive member 140 used for wrapping is attached to the non-metallic sheet 121 side. In this embodiment of the printing cylinder 21, the thin non-metallic sheet 121 can be attached to the printing cylinder 21 by the adhesive member 140 attached to the thin non-metallic sheet 121 side.

[0115] (18) In the printing cylinder 21 described in item (16) above, the adhesive member 140 used for wrapping is preferably breathable in a direction substantially perpendicular to the tangent line that is in contact with the printing cylinder 21. The printing cylinder 21 according to this embodiment can ensure breathability between the inside and the outside.

[0116] (19) In the printing cylinder 21 of item (7) above, the paper sheets 122a and 122b which are the base material of the nonmetallic sheet 121 may be one or more paper sheets selected from a material with flame retardant function, a material with moisture absorption prevention function, a material with antistatic function, dust-free paper, and a paper sheet with a coated surface.

[0117] When the paper sheets 122a and 122b are materials with added flame-retardant properties, the printing cylinder 21 according to this embodiment can achieve a higher heat resistance temperature.

[0118] Furthermore, if the paper sheets 122a and 122b are materials with added moisture-resistant properties, the printing cylinder 21 according to this embodiment can improve water resistance. Therefore, the printing cylinder 21 can, for example, maintain a constant size for the paper sheets 122a and 122b, thereby suppressing the formation of wrinkles in the paper sheets 122a and 122b. Such a printing cylinder 21 can improve (or maintain) print quality.

[0119] Furthermore, if the paper sheets 122a and 122b are materials with added antistatic properties, the printing cylinder 21 according to this embodiment can be configured to have an antistatic function. As a result, the printing cylinder 21 can prevent electrostatic adhesion of the paper sheets 122a and 122b, and can suppress the formation of wrinkles on the paper sheets 122a and 122b. Such a printing cylinder 21 can improve (or maintain) print quality.

[0120] Furthermore, when the paper sheets 122a and 122b are dust-free paper, the printing cylinder 21 according to this embodiment can suppress the deterioration of transport quality and printing quality due to clogging of the through holes 131a and 131b (through hole 131) because the paper sheets 122a and 122b are dust-free paper.

[0121] Furthermore, if the paper sheets 122a and 122b are coated, the printing cylinder 21 according to this embodiment can impart any desired properties to the paper sheets 122a and 122b through the coating.

[0122] (20) In the printing cylinder 21 described in item (19) above, the coating applied to the surface of the paper sheets 122a and 122b may be one or more types of flame-retardant coating, water-repellent coating, antistatic coating, and dustproof coating. The printing cylinder 21 according to this embodiment can impart properties such as flame retardancy, water repellency, antistatic properties, and dustproof properties to the paper sheets 122a and 122b through the coating.

[0123] (21) As shown in Figure 1, the image forming apparatus (inkjet printing apparatus 100) according to this embodiment includes a printing cylinder 21 and an inkjet head unit 24. The printing cylinder 21 is a transport unit that transports the printing media 200. The inkjet head unit 24 is an image forming unit that forms an image on the printing media 200 transported by the printing cylinder 21. The printing cylinder 21 has a non-metallic sheet 121 on its outer peripheral surface 21a. The non-metallic sheet 121 has a heat resistance temperature of 200°C or higher and a static friction coefficient with the printing media 200 of 0.2 or more and 0.9 or less. The image forming apparatus according to this embodiment has high heat resistance and can suppress the occurrence of slippage of the printing media 200.

[0124] (22) As shown in Figure 3, in the image forming apparatus of item (21) above, the thermal conductivity of the nonmetallic sheet 121 is set to be less than 2 W / m·K. In this image forming apparatus according to this embodiment, since the thermal conductivity of the nonmetallic sheet 121 is less than 2 W / m·K, it is possible to make it difficult for heat to be transferred (i.e., to suppress heat transfer). In this image forming apparatus, especially when performing double-sided printing, it is possible to prevent the printing medium 200 from sticking to the printing cylinder 21 due to the printing cylinder 21 becoming hot and heat from becoming trapped inside the printing cylinder 21.

[0125] (23) As shown in Figure 1, the image forming apparatus described in item (21) above is configured as an image forming apparatus capable of single-fed printing and double-sided printing. Such an image forming apparatus according to this embodiment can prevent heat from becoming trapped inside the inkjet head unit 24 (image forming section), which would prevent the formation of a good image on the printing media 200. Such an image forming apparatus can improve print quality.

[0126] (24) As shown in Figure 1, in the image forming apparatus of item (21) above, the inkjet head unit 24 (image forming section) has an ejection section (inkjet heads 24Y, 24M, 24C, 24K) for ejecting ink. The ejection section uses UV ink that is UV light cured on the printing medium 200 held by the printing cylinder 21 as the ink, and ejects the UV ink at a temperature higher than the temperature of the printing medium 200. In this embodiment of the image forming apparatus, by ensuring good wettability with UV ink, it is possible to easily form fine dots. Such an image forming apparatus can improve print quality.

[0127] (25) As shown in Figure 4, in the image forming apparatus described in item (21) above, the non-metallic sheet 121 is based on a paper sheet made of cellulose. The thickness of the paper sheet, which is the base material of the non-metallic sheet 121, is from 0.08 mm to 10 mm. By using a paper material (paper sheet) as the base material of the non-metallic sheet 121, the image forming apparatus according to this embodiment can achieve both environmental friendliness and heat resistance. Furthermore, the image forming apparatus can obtain suitable strength, wrinkle resistance, heat insulation, and hole processing performance for the printing cylinder 21.

[0128] (26) As shown in Figure 4, in the image forming apparatus of item (21) above, the non-metallic sheet 121 is made of a non-organofluorine compound. Since the image forming apparatus according to this embodiment uses a printing cylinder 21 that can withstand use in high-temperature areas near the heater 302, the operating time can be extended.

[0129] (27) As shown in Figure 4, in the image forming apparatus of item (21) above, the non-metallic sheet 121 mainly consists of raw materials selected from one or more of cellulose, glass, carbon, calcium, and ceramic. Such an image forming apparatus according to this embodiment can have high heat resistance while suppressing the occurrence of slippage of the printing media 200.

[0130] (28) As shown in Figure 4, in the image forming apparatus described in item (21) above, the non-metallic sheet 121 is based on a paper sheet made of cellulose. By using a paper material (paper sheet) as the base material for the non-metallic sheet 121, the image forming apparatus according to this embodiment can achieve both environmental friendliness and heat resistance. Furthermore, the image forming apparatus can obtain suitable strength, wrinkle resistance, heat insulation, and pore processing properties.

[0131] As described above, according to this embodiment, it is possible to provide a printing cylinder 21 that has high heat resistance while suppressing the occurrence of slippage of the printing media, and an inkjet printing apparatus 100 (image forming apparatus) equipped with the printing cylinder 21.

[0132] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and variations can be made without departing from the spirit of the invention. For example, the inkjet printing apparatus 100 does not necessarily have to be a printing apparatus that uses a filling-type inert gas supply method. Also, in order to improve adhesion, a stainless steel sheet or the like may be wrapped around the outer circumferential surface 21a of the printing cylinder, and a non-metallic sheet may be wrapped on top of the stainless steel sheet.

[0133] For example, the embodiments described above are explained in detail to make the gist of the present invention easier to understand. Therefore, the present invention is not necessarily limited to having all the components described. Furthermore, the present invention can be modified by adding other components to one component, or by changing some components to other components. Furthermore, the present invention can be modified by deleting some components. [Explanation of symbols]

[0134] 10 Paper feed section 11 Paper feed tray 12 Media supply section 20 Image recording unit 21 Printing cylinder (conveyor drum, conveyor section) 21a Outer surface (conveying surface) 22 Transfer drum 22a Koro 24. Inkjet head unit (image forming section) 24Y, 24M, 24C, 24K inkjet head (ejector) 25 Active ray irradiation section 26 Separation part 26a, 26b, 26c Conveyor rollers 27 Belt conveying section 28. Paper reversal section (reversal mechanism) 28a Conveyor roller (reversing section) 30 Paper output section 31 Paper output tray 41 Torso 41a Through hole 90 Control Unit 100 Inkjet printing apparatus (image forming apparatus) 121 Non-metallic sheet 122a, 122b Paper sheet 131a,131b through hole 140 Adhesive material 190 Sheet supply unit 200 Print media (recording media) 301,302 Heater 303 Fans 401,402 areas

Claims

1. A printing cylinder for transporting printing media, The outer surface has a non-metallic sheet with a heat resistance temperature of 200°C or higher and a static friction coefficient with the printing media of 0.2 or more and 0.9 or less. Printing cylinder.

2. The aforementioned non-metallic sheet has a surface roughness of 0.2 mm or less. The printing cylinder according to claim 1.

3. The Young's modulus of the nonmetallic sheet is 72 GPa or higher. The printing cylinder according to claim 1.

4. The static friction coefficient of the non-metallic sheet with respect to the printing medium is 0.3 or more and 0.8 or less. The printing cylinder according to claim 1.

5. The thermal conductivity of the aforementioned nonmetallic sheet is less than 2 W / m·K. The printing cylinder according to claim 1.

6. The aforementioned non-metallic sheet is based on a material whose main component is one or more raw materials selected from cellulose, glass, carbon, calcium, and ceramic. The printing cylinder according to claim 1.

7. The aforementioned non-metallic sheet uses a paper sheet composed of cellulose as its base material. The printing cylinder according to claim 1.

8. The aforementioned paper sheet consists of multiple sheets stacked on top of each other. The printing cylinder according to claim 7.

9. The aforementioned nonmetallic sheet has a heat resistance temperature of 260°C or higher and is composed of a non-organic fluorine compound. The printing cylinder according to claim 1.

10. The aforementioned nonmetallic sheet has a heat resistance temperature of 300°C or higher and is composed of a non-organic fluorine compound. The printing cylinder according to claim 1.

11. The non-metallic sheet has breathability in a direction perpendicular to the tangent line that contacts the printing cylinder. The printing cylinder according to claim 1.

12. The aforementioned ventilation is ensured by through holes formed perpendicular to the tangent line in contact with the printing cylinder. The printing cylinder according to claim 11.

13. The aforementioned through hole has a shape without corners. The printing cylinder according to claim 12.

14. The through-hole has an elongated elliptical shape along the conveying direction. The printing cylinder according to claim 13.

15. The aforementioned through holes are arranged in a staggered pattern. The printing cylinder according to claim 13.

16. The non-metallic sheet is wrapped around the cylinder body of the printing cylinder, The method for wrapping the non-metallic sheet around the body is a method selected from at least one of tension wrapping and adhesive attachment. The printing cylinder according to claim 1.

17. The adhesive material used for wrapping is attached to the non-metallic sheet side. The printing cylinder according to claim 16.

18. The adhesive material used for wrapping has breathability in the direction perpendicular to the tangent line in contact with the printing cylinder. The printing cylinder according to claim 16.

19. The paper sheet, which is the base material for the non-metallic sheet, is one or more selected paper sheets from among a member with flame-retardant properties, a member with moisture-resistant properties, a member with antistatic properties, dust-free paper, and a paper sheet with a coated surface. The printing cylinder according to claim 7.

20. The coating applied to the surface of the aforementioned paper sheet is one or more of the following: flame-retardant coating, water-repellent coating, antistatic coating, and dustproof coating. The printing cylinder according to claim 19.

21. A printing cylinder that transports the printing media, It has an image forming unit that forms an image on a printing medium conveyed by the printing cylinder, The printing cylinder has a heat resistance temperature of 200°C or higher and a non-metallic sheet on its outer surface having a static friction coefficient of 0.2 or higher and 0.9 or lower with respect to the printing media. Image forming apparatus.

22. The thermal conductivity of the aforementioned nonmetallic sheet is set to be less than 2 W / m·K. The image forming apparatus according to claim 21.

23. It is configured as an inkjet printer capable of sheet-fed and double-sided printing. The image forming apparatus according to claim 21.

24. The image forming unit has an ink ejection unit, The ejection unit uses UV ink, which is UV-curable on the printing medium held by the printing cylinder, as the ink, and ejects the UV ink at a temperature higher than the temperature of the printing medium. The image forming apparatus according to claim 21.

25. The aforementioned non-metallic sheet uses a paper sheet made of cellulose as its base material. The thickness of the paper sheet, which is the base material for the non-metallic sheet, is between 0.08 mm and 10 mm. The image forming apparatus according to claim 21.

26. The aforementioned nonmetallic sheet is composed of a non-organofluorine compound. The image forming apparatus according to claim 21.

27. The aforementioned non-metallic sheet mainly consists of one or more raw materials selected from cellulose, glass, carbon, calcium, and ceramic. The image forming apparatus according to claim 21.

28. The aforementioned non-metallic sheet uses a paper sheet composed of cellulose as its base material. The image forming apparatus according to claim 21.

Images