JP2013041121A - Cylindrical member, transfer device, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical member formed by laminating a plurality of layers different in linear expansion coefficient in a thickness direction, which is configured to prevent deformation in a lateral end when demolded after temperature reduction, a transfer device, and an image forming device.SOLUTION: An intermediate transfer belt 102 is flexible, and is formed in a cylindrical shape by laminating a lower layer film 102A and an upper layer film 102B different in linear expansion coefficient in a thickness direction D. In the upper layer film 102B having the largest linear expansion coefficient, grooves 103 long in a circumferential direction are formed. When the temperature of the heated intermediate transfer belt 102 is reduced, transmission of internal stress to contract the upper layer film 102B is prevented by the grooves 103 formed in the upper layer film 102B, thereby preventing the lateral end of the intermediate transfer belt 102 from being deformed toward the upper layer film 102B.

Description

  The present invention relates to a cylindrical member, a transfer device, and an image forming apparatus.

  The endless belt of Patent Document 1 is formed by centrifugal molding using a solution obtained by dissolving a polyamide-imide resin in a solvent. After centrifugal molding, the endless belt is dried in an oxygen-blocked atmosphere before demolding. And the curvature amount when heat-processing is prescribed | regulated is 20 mm or less.

  The semiconductive belt of Patent Document 2 has an outer layer and an inner layer mainly composed of a polyimide resin, and the linear expansion coefficient of the inner layer is larger than that of the outer layer.

JP 2006-330539 A JP 2002-365927 A

  The present invention relates to a cylindrical member capable of suppressing deformation of the end portion in the width direction after the cylindrical member laminated in the thickness direction including a plurality of layers having different linear expansion coefficients is demolded by lowering the temperature. It is an object to obtain a transfer device and an image forming apparatus.

  The cylindrical member according to claim 1 of the present invention is a layer having the largest linear expansion coefficient, which is flexible and includes a plurality of layers having different linear expansion coefficients and is laminated in the thickness direction to form a cylindrical shape. A groove having a circumferential direction as a longitudinal direction is formed at an end in the width direction.

  In the cylindrical member according to claim 2 of the present invention, the layer having the largest linear expansion coefficient is the innermost layer or the outermost layer, and the groove is formed on the surface of the innermost layer or the surface of the outermost layer.

  According to a third aspect of the present invention, there is provided a transfer device, wherein the cylindrical member according to the first or second aspect, the image holding body that holds a developer image, and the cylindrical member are in contact with each other. A plurality of rotating members that rotatably support the member, and a transfer unit that is provided inside the cylindrical member and transfers the developer image of the image holding member to the outer peripheral surface of the cylindrical member by a potential difference. .

  According to a fourth aspect of the present invention, there is provided an image forming apparatus comprising: a developer image forming unit that forms a developer image on the image holding member; and a developer image of the image holding member formed by the developer image forming unit. And a transfer device according to claim 3 for transferring to the cylindrical member.

  The invention of claim 1 includes a plurality of layers having different linear expansion coefficients as compared with a configuration in which a groove having a longitudinal direction in the circumferential direction is not formed at the end in the width direction of the layer having the largest linear expansion coefficient. It is possible to suppress deformation of the end portion in the width direction after the cylindrical members stacked in the thickness direction are demolded by lowering the temperature.

  The invention of claim 2 can suppress the deformation of the cylindrical member as compared with the configuration in which the peripheral edge of the groove is restrained by another layer.

  The invention of claim 3 is transferred to the cylindrical member as compared with the configuration having the cylindrical member in which the groove having the circumferential direction as the longitudinal direction is not formed at the end in the width direction of the layer having the largest linear expansion coefficient. The uneven transfer of the developer image can be suppressed.

  The invention according to claim 4 suppresses uneven image density as compared with a configuration having a cylindrical member in which a groove having a longitudinal direction in the circumferential direction is not formed at an end in the width direction of a layer having the largest linear expansion coefficient. be able to.

1 is an overall configuration diagram of an image forming apparatus according to an embodiment of the present invention. 1 is a configuration diagram of an image forming unit according to an embodiment of the present invention. FIG. FIG. 3A is a longitudinal sectional view of an intermediate transfer belt according to an embodiment of the present invention. (B) It is a longitudinal cross-sectional view of the edge part of the intermediate transfer belt which concerns on embodiment of this invention. (A) It is the schematic which shows the state which apply | coats a polyimide solution to the outer peripheral surface of a cylindrical forming tube as an example of the manufacturing method of the intermediate transfer belt which concerns on embodiment of this invention. (B) It is a longitudinal cross-sectional view which shows the state which formed the groove | channel in the edge part of the intermediate transfer belt which concerns on embodiment of this invention. (A), (B), (C) It is explanatory drawing which shows the shaping | molding of an intermediate transfer belt which concerns on embodiment of this invention, groove | channel formation, and a demolding process. FIG. 6A is a schematic diagram illustrating a state in which the end portion of the intermediate transfer belt of the comparative example is warped. FIG. 4B is a schematic diagram illustrating a state in which warpage is suppressed at an end portion of the intermediate transfer belt according to the embodiment of the invention. (A) and (B) are schematic views illustrating a method for measuring the flatness of an intermediate transfer belt according to an embodiment of the present invention. FIG. 6 is a longitudinal sectional view showing a state where grooves are formed on the inner side as a modification of the intermediate transfer belt according to the embodiment of the present invention.

  An example of a cylindrical member, a transfer device, and an image forming apparatus according to an embodiment of the present invention will be described.

  FIG. 1 shows an image forming apparatus 10 as an example of the present embodiment. The image forming apparatus 10 forms a color image or a black and white image. The first processing unit 10A disposed on the left side in front view and the second processing unit 10A that is detachable from the first processing unit 10A are disposed on the right side. And a processing unit 10B. The housings of the first processing unit 10A and the second processing unit 10B are composed of a plurality of frame materials. In the following description, the length direction of the image forming apparatus 10 (the sub-scanning direction that is the conveyance direction of the recording paper P as an example of the medium) is the X direction, the height direction of the apparatus is the Y direction, and the depth direction of the apparatus. Let (the main scanning direction) be the Z direction.

  The first special color (V), second special color (W), yellow (Y), magenta (M), cyan (C), and black (K) toner are accommodated in the upper portion of the first processing unit 10A. Toner cartridges 14V, 14W, 14Y, 14M, 14C, and 14K are provided so as to be replaceable along the X direction.

  The first special color (V) and the second special color (W) are appropriately selected from colors (including transparent) other than yellow, magenta, cyan, and black. In the following description, the first special color (V), the second special color (W), yellow (Y), magenta (M), cyan (C), and black (K) are distinguished for each component. Is described with a letter followed by any letter of V, W, Y, M, C, or K. The first special color (V), the second special color (W), yellow (Y), magenta When not distinguishing (M), cyan (C), and black (K), V, W, Y, M, C, and K are omitted.

  Further, under the toner cartridge 14, image forming units 16 as an example of six developer image forming units corresponding to the toners of the respective colors are provided along the X direction so as to correspond to the toner cartridges 14. ing. Then, the exposure device 40 provided for each image forming unit 16 receives the image data subjected to the image processing by the image signal processing unit 13 provided in the upper part of the second processing unit 10B, and according to the image data. The modulated light beam L is irradiated to a photoconductor 18 (see FIG. 2) described later.

  As shown in FIG. 2, each image forming unit 16 includes a photoconductor 18 as an example of an image carrier that is rotationally driven in an arrow R direction (clockwise direction in the drawing). On each photoconductor 18, an electrostatic latent image is formed by irradiating the light beam L from each exposure device 40. Here, the exposure device 40 scans the light emitted from the light source (not shown) in the main scanning direction by the polygon mirror 43, and also uses the plurality of optical components 45 including the fθ lens and the reflection mirror to the outer peripheral surface of the photosensitive member 18. Is exposed to a light beam L.

  Around each photoconductor 18, a corona discharge method (non-contact charging method) scorotron charger 20 that charges the photoconductor 18 and an electrostatic latent image formed on the photoconductor 18 by the exposure device 40 are developed by a developer ( The developing device 22 for developing with toner), the blade 24 for removing the developer remaining on the photoconductor 18 after the primary transfer, and the photoconductor 18 after removing the developer by the blade 24 are irradiated with light to perform static elimination. A static elimination device 26 is provided. The scorotron charger 20, the developing device 22, the blade 24, and the charge eliminating device 26 are arranged in this order from the upstream side to the downstream side in the rotation direction of the photoconductor 18 so as to face the surface of the photoconductor 18. ing.

  The developing device 22 includes a developer accommodating member 22A that accommodates a developer G containing toner, and a developing roll 22B that supplies the developer G accommodated in the developer accommodating member 22A to the photoconductor 18. ing. The developer accommodating member 22A is connected to the toner cartridge 14 (see FIG. 1) via a toner supply path (not shown) so that the toner is supplied from the toner cartridge 14.

  On the other hand, as shown in FIG. 1, a transfer unit 100 as an example of a transfer device is provided below each image forming unit 16. The transfer unit 100 includes an intermediate transfer belt 102 as an example of a cylindrical member whose outer peripheral surface is in contact with the outer peripheral surface of each photoconductor 18, and driving as an example of a plurality of rotating members that rotatably support the intermediate transfer belt 102. Provided inside the intermediate transfer belt 102 with the roll 104, the tension applying roll 106, the opposing roll 108, the winding roll 110, and the intermediate transfer belt 102, the developer image (toner image) of the photosensitive member 18 (see FIG. 2) is intermediate transferred. It includes a primary transfer roll 112 as an example of transfer means for transferring to the outer peripheral surface of the belt 102.

  The drive roll 104 is driven by a motor (not shown), and the tension applying roll 106 is biased by springs (not shown) at both ends in the axial direction to apply tension to the intermediate transfer belt 102. doing. The opposing roll 108 is rotatably provided at a position facing a secondary transfer roll 62 (to be described later) with the intermediate transfer belt 102 interposed therebetween. The winding roll 110 moves the intermediate transfer belt 102 in the moving direction (arrow A). A plurality of rotations are provided at intervals in the direction). The intermediate transfer belt 102 is wound around a driving roll 104, a tension applying roll 106, an opposing roll 108, and a plurality of winding rolls 110, and the driving roll 104 causes an arrow A direction (counterclockwise direction shown in the figure). ) In a circular movement.

  As shown in FIG. 2, each primary transfer roll 112 is disposed opposite to the photoreceptor 18 of each image forming unit 16 with the intermediate transfer belt 102 interposed therebetween. The primary transfer roll 112 is applied with a transfer bias voltage having a polarity opposite to the toner polarity by a power supply unit 114 as an example of a transfer unit. With this configuration, the toner image formed on the photoreceptor 18 is transferred to the intermediate transfer belt 102.

  As shown in FIG. 1, a removal device 46 that removes residual toner, paper dust, and the like on the intermediate transfer belt 102 is provided on the opposite side of the drive roll 104 with the intermediate transfer belt 102 interposed therebetween. The removing device 46 has a configuration in which a blade is brought into contact with the outer peripheral surface of the intermediate transfer belt 102. Further, below the transfer unit 100, two paper storage portions 48 for storing the recording paper P are provided along the X direction.

  Each paper storage unit 48 can be pulled out from the first processing unit 10A to the front side in the Z direction. Further, a delivery roll 52 for sending the recording paper P from each paper storage unit 48 to the transport path 60 is provided above one end side (right side in FIG. 1) of each paper storage unit 48. Further, a bottom plate 50 on which the recording paper P is placed is provided in each paper storage portion 48. The bottom plate 50 is lowered by an instruction from a control unit (not shown) when the paper storage unit 48 is pulled out from the first processing unit 10A. Then, as the bottom plate 50 is lowered, a space for the user to replenish the recording paper P is formed in the paper storage portion 48.

  On the other hand, when the paper storage unit 48 pulled out from the first processing unit 10A is attached to the first processing unit 10A, the bottom plate 50 is raised by an instruction from the control means. As the bottom plate 50 is raised, the uppermost recording paper P placed on the bottom plate 50 and the delivery roll 52 come into contact with each other. Further, on the downstream side of the feeding roll 52 in the conveyance direction of the recording paper P (hereinafter sometimes simply referred to as “downstream side”), the recording paper P that is fed out from the paper storage section 48 is sent one by one. A separation roll 56 for separation is provided. A plurality of transport rolls 54 that transport the recording paper P downstream in the transport direction are provided on the downstream side of the separation roll 56.

  The conveyance path 60 provided between the paper storage unit 48 and the transfer unit 30 includes a first folding unit 60A and a second folding unit 60B. Then, the recording paper P sent out from the paper storage unit 48 is folded and conveyed to the left side in FIG. 1 by the first folding unit 60A, and further folded to the right side in FIG. 1 by the second folding unit 60B. It is conveyed to the transfer position T between the transfer roll 62 and the opposing roll 108.

  The secondary transfer roll 62 is applied with a transfer bias voltage having a polarity opposite to the toner polarity by a power feeding unit (not shown). The toner images of the respective colors that have been multiplex-transferred (primary transfer) to the intermediate transfer belt 102 are secondarily transferred onto the recording paper P that has been transported along the transport path 60 by the secondary transfer roll 62. ing.

  In addition, a preliminary path 66 extending from the left side surface of the first processing unit 10A is provided so as to join the second folding unit 60B of the transport path 60. Then, the recording paper P sent out from another recording medium storage unit (not shown) arranged adjacent to the left side of the first processing unit 10A can enter the conveyance path 60 through the spare path 66. Yes.

  On the other hand, on the downstream side of the transfer position T in the transport path 60 of the first processing unit 10A, a plurality of transport belts 70 are provided for transporting the recording paper P onto which the toner image has been transferred toward the second processing unit 10B. Yes. The second processing unit 10B is provided with a conveyance belt 80 that conveys the recording paper P conveyed by the conveyance belt 70 to the downstream side.

  Each of the plurality of conveyor belts 70 and the conveyor belt 80 is formed in an annular shape (tubular shape) and is wound around a pair of winding rolls 72. The pair of winding rolls 72 are respectively arranged on the upstream side and the downstream side in the conveyance direction of the recording paper P, and when one of them is driven to rotate, the conveyance belt 70 and the conveyance belt 80 are moved in one direction (the timepiece in FIG. Cycle in the direction of rotation). Further, on the downstream side of the conveying belt 80, a fixing unit 82 for fixing the toner image transferred (image formed) on the surface of the recording paper P to the recording paper P by the action of heat and pressure is provided.

  The fixing unit 82 is disposed so as to contact the fixing belt 84 disposed on the upper side of the conveyance path 60 (on the image forming surface side of the recording paper P) and the fixing belt 84 from below with the conveyance path 60 interposed therebetween. A pressure roll 88. A fixing unit N is formed between the fixing belt 84 and the pressure roll 88 to press and heat the recording paper P to fix the toner image.

  The fixing belt 84 is formed in an annular shape, and is wound around a drive roll 89 and a driven roll 90 that are arranged vertically. The drive roll 89 faces the pressure roll 88 from above, and the driven roll 90 is disposed above the drive roll 89. Each of the drive roll 89 and the driven roll 90 includes a heating unit such as a halogen heater. As a result, the fixing belt 84 is heated.

  On the downstream side of the fixing unit 82, a conveyance belt 152 that conveys the recording paper P sent out from the fixing unit 82 to the downstream side is provided. The conveyor belt 152 has the same configuration as the conveyor belt 70. A cooling unit 160 that cools the recording paper P heated by the fixing unit 82 is provided on the downstream side of the conveyance belt 152.

  The cooling unit 160 includes an absorption device 162 that absorbs the heat of the recording paper P and a pressing device 164 that presses the recording paper P against the absorption device 162. The absorbing device 162 is disposed on one side (upper side in FIG. 1) with respect to the transport path 60, and the pressing device 164 is disposed on the other side (lower side in FIG. 1).

  The absorbing device 162 includes an annular absorbing belt 166 that contacts the recording paper P and absorbs the heat of the recording paper P. The absorption belt 166 is wound around a driving roll 170 that transmits a driving force to the absorption belt 166 and a plurality of winding rolls 168. Further, a heat sink 172 made of an aluminum material that dissipates heat absorbed by the absorption belt 166 by contacting the absorption belt 166 in a planar shape is provided on the inner peripheral side of the absorption belt 166. Further, a fan 174 for discharging hot air generated by heat radiation of the heat sink 172 to the outside is provided on the back side of the second processing unit 10B (the back side in FIG. 1).

  The pressing device 164 includes an annular pressing belt 180 that conveys the recording paper P while pressing the recording paper P against the absorption belt 166. The pressing belt 180 is wound around a plurality of winding rolls 182.

  Further, on the downstream side of the cooling unit 160 on the conveyance path 60, a correction device 190 that conveys the recording paper P and corrects the curl of the recording paper P is provided. Further, on the downstream side of the correction device 190 on the conveyance path 60, a discharge roll 198 is provided for discharging the recording paper P on which an image is formed on one side to a discharge unit 196 attached to the side surface of the second processing unit 10B. ing. On the other hand, when images are formed on both sides of the recording paper P, the recording paper P sent out from the correction device 190 is conveyed to the reverse path 194.

  The reversing path 194 includes a branch path 194A that branches from the transport path 60, a paper transport path 194B that transports the recording paper P transported along the branch path 194A toward the first processing unit 10A, and a paper transport path. A reversing path 194C is provided to turn the recording paper P conveyed along 194B in the reverse direction and switch it back to reverse the front and back. With this configuration, the recording paper P that has been switched back in the reverse path 194C is transported toward the first processing unit 10A, and further enters the transport path 60 provided above the paper storage unit 48, so that the transfer position T Will be sent again.

  Next, an image forming process of the image forming apparatus 10 will be described.

  As shown in FIG. 1, first, image data subjected to image processing by the image signal processing unit 13 is sent to each exposure device 40. As shown in FIG. 2, each exposure device 40 emits each light beam L in accordance with the image data, exposes the outer peripheral surface of each photoconductor 18 charged by the scorotron charger 20, and electrostatic latent An image is formed. Further, the electrostatic latent image formed on the photoconductor 18 is developed by the developing device 22, and the first special color (V), the second special color (W), yellow (Y), magenta (M), cyan ( C) and black (K) toner images are formed.

  Subsequently, as shown in FIG. 1, the toner images of the respective colors formed on the photoreceptors 18 (see FIG. 2) of the respective image forming units 16V, 16W, 16Y, 16M, 16C, and 16K are composed of six primary transfer rolls 36V. , 36W, 36Y, 36M, 36C, and 36K, the images are sequentially transferred to the intermediate transfer belt 34 by multiple transfer. The toner images of the respective colors that have been multiplex-transferred onto the intermediate transfer belt 34 are secondarily transferred by the secondary transfer roll 62 onto the recording paper P conveyed from the paper storage unit 48. Further, the recording paper P onto which the toner image has been transferred is conveyed toward the fixing unit 82 provided inside the second processing unit 10B by the conveying belt 70.

  Subsequently, in the fixing unit 82, the toner images of the respective colors on the recording paper P are fixed on the recording paper P by being heated and pressurized. Then, the recording paper P on which the toner image is fixed is cooled by passing through the cooling unit 160 and then sent to the correction device 190 to correct the curvature generated on the recording paper P. Further, the recording paper P whose curvature is corrected is discharged to the discharge unit 196 by the discharge roll 198.

  On the other hand, when an image is to be formed on the non-image surface of the recording paper P on which the image is not formed (in the case of double-sided printing), the recording paper P passes through the correction device 190, and then the recording paper P passes through the reverse path 194. The toner image is reversed and further fed into a conveyance path 60 provided above the sheet storage portion 48, and a toner image is formed on the back surface in the above-described procedure.

  In the image forming apparatus 10 according to the present embodiment, components for forming images of the first special color and the second special color (image forming units 16V and 16W, exposure devices 40V and 40W, toner cartridges 14V and 14W, The primary transfer rolls 36V and 36W) are configured to be attachable to or detachable from the first processing unit 10A as additional parts according to the user's selection. Accordingly, the image forming apparatus 10 does not include a part for forming the first special color and second special color images, and the image of any one of the first special color and the second special color. It is good also as a structure which has only the components for forming.

  Next, the intermediate transfer belt 102 will be described.

  As shown in FIGS. 3A and 3B, the intermediate transfer belt 102 is a two-layered cylindrical body in which an upper layer film 102B is laminated on a lower layer film 102A. The lower layer film 102A is an inner layer, and as an example, carbon black is added to a polyimide resin. On the other hand, the upper layer film 102B is an outer layer. For example, carbon black and a fluorine-based resin are added to a polyimide resin. And by adding fluororesin, the linear expansion coefficient of the upper layer film 102B is larger than the linear expansion coefficient of the lower layer film 102A. In addition, a plurality of grooves 103 whose longitudinal direction is the circumferential direction r are formed at the end in the width direction W of the upper layer film 102B. The linear expansion coefficient is measured according to JIS K7197.

  Here, as an example of a method for producing the intermediate transfer belt 102, carbon black (special black 4) is added to polyimide resin (solvent is n-methyl-2-pyrrolidone), and dispersion and preparation are performed to obtain a coating liquid A ( 4A) is obtained. Further, a fluorine-based resin (PTFE (polytetrafluoroethylene)) is added to the coating liquid A, and dispersion and preparation are performed to obtain a coating liquid B (see FIG. 4A).

  Subsequently, as shown in FIG. 4A, the nozzle 144 is moved in the axial direction of the pipe 140 in a state where the aluminum pipe 140 (core metal) which is a mold is rotated in the arrow r direction which is the circumferential direction. While being relatively moved in the direction of arrow W), the coating liquid A is pressurized by the pressurizing device 146, and the coating liquid A is allowed to flow down from the container 142 through the nozzle 144 to the outer peripheral surface of the pipe 140 and is applied in a spiral shape. In addition, the coating blade 148 is arrange | positioned so that the space | interval with the pipe 140 may become the space | interval set beforehand in the position facing the outer peripheral surface of the pipe 140. FIG. Here, the coating thickness of the coating liquid A is adjusted by passing the coating liquid A between the outer peripheral surface of the pipe 140 and the tip of the coating blade 148. And after application | coating of the coating liquid A, as an example, the coating liquid A is dried, rotating the pipe 140 for 30 minutes at 150 degreeC.

  Subsequently, the coating liquid B is applied on the lower layer film 102A obtained by drying in the same manner as the coating liquid A. As an example, the coating liquid B is dried while rotating the pipe 140 at 150 ° C. for 30 minutes. After this drying, as an example, the pipe 140 is taken out after being fired in an oven (not shown) at 315 ° C. for 1 hour. Thus, in the thickness direction D, the upper layer film 102B (see FIG. 3A) is laminated on the lower layer film 102A to form a cylindrical shape, and the intermediate transfer belt 102 having flexibility is formed as shown in FIG. As shown in FIG.

  Subsequently, before removing the intermediate transfer belt 102 from the pipe 140, as shown in FIG. 4B, on the outer peripheral surface of both end portions in the width direction W of the upper layer film 102B (in the range from each end to the width W1). Sandpaper 149 is brought into contact, and the pipe 140 is rotated and polished in the circumferential direction (arrow r direction). As a result, as shown in FIGS. 3A, 3B, and 5B, the circumferential direction R is set to the longitudinal direction in the range of the width W1 at both ends of the intermediate transfer belt 102 having the overall width W3. A plurality of grooves 103 are formed. The portion of the intermediate transfer belt 102 where the groove 103 is formed has a rougher surface than other portions, and is a thin portion.

  Here, in the intermediate transfer belt 102, the width of the range in contact with the recording paper P (see FIG. 1) is W2, and W3 = 2 × W1 + W2. That is, the range (2 × W1) of the intermediate transfer belt 102 that is polished in the width direction is a range that does not contact the recording paper P. In FIG. 4B, as an example, the surface shape of the sandpaper 149 is formed by a plurality of convex portions 149A having a triangular longitudinal section, and the groove 103 of the intermediate transfer belt 102 is formed in a V-shape. Shown with grooves. Further, as an example, the depth of the plurality of grooves 103 is 15 to 25% when the total film thickness d of the intermediate transfer belt 102 is 100%, and the width W1 is set to 40 mm. As an example, the thickness of the lower layer film 102A is 33 μm, the thickness of the upper layer film 102B is 67 μm, and the total film thickness is 100 μm.

  Subsequently, as shown in FIG. 5C, the intermediate transfer belt 102 is extracted from the pipe 140, and the intermediate transfer belt 102 is completed. The completed intermediate transfer belt 102 is hung on a rack (not shown) and stored.

  Next, an intermediate transfer belt 105 of a comparative example will be described.

  FIG. 6A shows a cross section of the intermediate transfer belt 105 as a comparative example with the present embodiment. The intermediate transfer belt 105 has no groove 103 (see FIG. 3B) formed on the outer periphery of the intermediate transfer belt 102, and the coating liquids A and B are applied to the outer periphery of the pipe 140 (see FIG. 4A). The manufacturing method from application to the surface to baking is the same as that of the intermediate transfer belt 102 of the present embodiment.

  In the intermediate transfer belt 105, the linear expansion coefficient of the upper film 102B formed by adding carbon black to the polyimide resin and further adding the fluororesin is the linear expansion coefficient of the lower film 102A in which carbon black is added to the polyimide resin. It is larger than For this reason, in the intermediate transfer belt 105 heated at the time of manufacture, the upper layer film 102B having a larger linear expansion coefficient is expanded more than the lower layer film 102A.

  Here, when the temperature of the intermediate transfer belt 105 is lowered after heating (after firing), the upper layer film 102B having a larger linear expansion coefficient contracts in the width direction than the lower layer film 102A. For this reason, the end portion of the intermediate transfer belt 105 is curved toward the upper layer film 102B after demolding (after the intermediate transfer belt 105 is removed from the pipe 140). In this way, the end of the intermediate transfer belt 105 of the comparative example is warped. In FIG. 6A, the amount of warping of the end portion of the intermediate transfer belt 105 is represented by a distance Δh1 that warps upward (away from) the reference plane M, with the lower surface of the lower layer film 102A as the reference plane M. .

  Next, the operation of this embodiment will be described.

  In the intermediate transfer belt 102 shown in FIG. 6B, the linear expansion coefficient of the upper layer film 102B is larger than the linear expansion coefficient of the lower layer film 102A because the fluororesin is dispersed (the most linear expansion coefficient). Is growing). For this reason, in the intermediate transfer belt 102 heated at the time of manufacture, the upper layer film 102B having a larger linear expansion coefficient is expanded more than the lower layer film 102A.

  Here, since a plurality of grooves 103 whose longitudinal direction is the circumferential direction r intersecting the width direction W are formed in the upper layer film 102B, the rigidity of the axial direction (width direction r) component of the upper layer film 102B is weak. It has become. That is, when the temperature of the intermediate transfer belt 102 is lowered after being heated (after firing), transmission of internal stress to shrink the upper layer film 102B is blocked by the groove 103, so that the internal stress of the upper layer film 102B is reduced. Alleviated. As a result, the end of the intermediate transfer belt 102 is prevented from being bent (deformed (curled)) toward the upper layer film 102B, and the amount of warpage of the end of the intermediate transfer belt 102 is Δh2 (<Δh1). In FIG. 6B, the amount of warping of the end portion of the intermediate transfer belt 102 is represented by a distance Δh2 that warps upward (away from) the reference plane M with the lower surface of the lower layer film 102A as the reference plane M. .

  Next, the flatness measurement performed for confirming the difference between the intermediate transfer belt 102 of the present embodiment and the intermediate transfer belt 105 of the comparative example will be described.

  As shown in FIG. 7A, the intermediate transfer belt 102 to be measured is stretched by two parallel shafts 212A and 212B, and a predetermined tension F (for example, F is applied to the intermediate transfer belt 102). = 19.6N) is stopped. In this state, the laser displacement meter 214 (LK-030 manufactured by Keyence Corporation) is moved in the width direction at a distance L1 (for example, L1 = 200 mm) from the center of the shaft 212A paired with the extending shaft 212B. Let W scan.

  Thereby, the distance between the outer peripheral surface of the intermediate transfer belt 102 and the laser displacement meter 214 is measured, and the unevenness amount of the intermediate transfer belt 102 in the width direction W shown in FIG. 7B is obtained. The flatness is measured at eight locations in the circumferential direction of the intermediate transfer belt 102. Then, for the range of width W4 excluding 15 mm from both ends in the width direction W, or the range of width W3, which is all the widths, the difference Δh between the maximum value Max and the minimum value Min of the obtained unevenness is defined as flatness. To do. Further, the flatness of the intermediate transfer belt 105 of the comparative example (see FIG. 6A) is measured in the same procedure.

  Here, the flatness of the intermediate transfer belt 102 of this embodiment was 0.25 mm, and the flatness of the intermediate transfer belt 105 of the comparative example was 0.61 mm. As a result, it was confirmed that the intermediate transfer belt 102 of the present embodiment has lower flatness (the amount of warpage is small and deformation is suppressed) than the intermediate transfer belt 105 of the comparative example.

  In the intermediate transfer belt 102 of this embodiment, as shown in FIGS. 3A and 3B, the upper layer film 102B having the largest linear expansion coefficient is formed in the outermost layer, and the groove 103 is formed on the surface of the upper layer film 102B. Therefore, the peripheral edge of the groove 103 is not constrained by the other lower layer film 102A. Therefore, the deformation of the intermediate transfer belt 102 is suppressed as compared with the configuration in which the groove 103 is formed on the lower film 102A side of the upper film 102B (the structure in which the peripheral edge of the groove 103 is constrained by the lower film 102A). Even when the intermediate transfer belt 102 is removed from the mold and hung on the rack, the deformation is suppressed, so that the end of the intermediate transfer belt 102 is prevented from being bent.

  Further, in FIG. 2, in the transfer unit 100 of the present embodiment, deformation at both ends in the width direction of the intermediate transfer belt 102 is suppressed, so that the intermediate transfer belt 102 and the photoreceptor 18 in the width direction of the intermediate transfer belt 102 are The variation in distance is reduced. As a result, when the toner image is transferred from the photoreceptor 18 to the intermediate transfer belt 102 using the power supply unit 114, the variation in the electric field strength in the width direction of the intermediate transfer belt 102 is reduced. It is suppressed.

  In addition, in FIG. 1, in the image forming apparatus 10 of the present embodiment, the toner image transfer unevenness is suppressed in the transfer unit 100, so that the density of the toner image on the recording paper P that is finally discharged to the discharge unit 196. Unevenness is suppressed.

  In addition, this invention is not limited to said embodiment.

  The belt member 202 as an example of the cylindrical member illustrated in FIG. 8B may be formed using the inner surface coating method illustrated in FIG. The belt member 202 includes a lower layer film 202B and an upper layer film 202A, and the lower layer film 202B has a higher linear expansion coefficient than the upper layer film 202A.

  As shown in FIG. 8A, in the manufacture of the belt member 202, the coating liquid A is allowed to flow down from the container 204 through the nozzle 205 as an example while rotating the pipe 140 in the direction of the arrow R. At this time, the discharge pressure is applied to the coating liquid A by the pressurizing device 206. And after apply | coating the coating liquid A to the internal peripheral surface of the pipe 140, it is made to dry and the upper layer film | membrane 202A shown to FIG. 8 (B) is formed.

  Subsequently, the above-described coating liquid B is applied to the inner side of the upper layer film 202A by the same procedure and then dried to form the lower layer film 202B, and the belt member 202 is formed. Then, after firing the belt member 202, the pipe 140 is rotated in a state where the sandpaper 208 having a plurality of convex portions 208A is in contact with the lower layer film 202B, thereby causing the lower layer film 202B of the belt member 202 to move in the circumferential direction R. A plurality of grooves 209 are formed in the longitudinal direction.

  Since the groove 209 is formed in a direction crossing the width direction W of the belt member 202, internal stress is accumulated when the belt member 202 is cooled. However, the internal stress that tends to shrink the lower layer film 202B is accumulated. Transmission is interrupted by the groove 209. Thereby, it is suppressed that the edge part of the belt member 202 curves (deforms) to the lower layer film 202B side. As described above, the groove 209 may be formed on the inner peripheral surface side of the belt member 202.

  As a modification, grooves may be formed at both ends of the fixing belt 84 in addition to the intermediate transfer belt 102 and the belt member 202. This is because in the fixing unit 82, the heating state by the heat source and the cooling state in which heat is removed by the recording paper P and the toner are repeatedly performed, so that deformation may occur at both ends of the fixing belt 84. If the deformation of both ends of the fixing belt 84 is suppressed, the meandering of the fixing belt 84 is suppressed.

  Further, the layer configuration of the intermediate transfer belt 102 and the belt member 202 is not limited to two layers, and may be a plurality of three or more layers. In the case of three or more layers, the linear expansion coefficient of the layer located on the innermost circumference in the thickness direction is compared with the linear expansion coefficient of the layer located on the outermost circumference. A groove may be formed on the surface of the larger layer.

  In addition, the grooves 103 and 209 only need to include at least a groove whose longitudinal direction is the circumferential direction R of the intermediate transfer belt 102 and the belt member 202. In addition, an oblique groove that intersects the circumferential direction R is formed. May be. The shape of the groove is not limited to a V shape, and may be a rectangular shape or a semicircular curved longitudinal section. Furthermore, the shapes and depths of the plurality of grooves 103 and 209 may not all be the same, and the shapes and depths may be different. In addition, the grooves may be formed not only intermittently in the circumferential direction but also continuously.

  Further, as a material of the pipe 140, nickel or stainless steel may be used in addition to aluminum. Furthermore, the outer peripheral surface of the pipe 140 may be plated with chromium or nickel, or covered with a fluororesin or a silicone resin.

10 image forming apparatus 16 image forming unit (an example of developer image forming means)
18 Photoconductor (an example of an image carrier)
100 Transfer unit (an example of a transfer device)
102 Intermediate transfer belt (an example of a cylindrical member)
103 groove 104 drive roll (an example of a rotating member)
106 Tension applying roll (an example of a rotating member)
108 Opposite roll (an example of a rotating member)
110 winding roll (an example of a rotating member)
112 Primary transfer roll (an example of transfer means)
114 Power supply unit (an example of transfer means)
202 Belt member (an example of a cylindrical member)

Claims (4)

  A plurality of layers having flexibility and different linear expansion coefficients are laminated in the thickness direction to form a cylinder, and the circumferential direction is the longitudinal direction at the end in the width direction of the layer having the largest linear expansion coefficient. A cylindrical member in which a groove is formed.   The cylindrical member according to claim 1, wherein a layer having the largest linear expansion coefficient is an innermost layer or an outermost layer, and the groove is formed on a surface of the innermost layer or a surface of the outermost layer. The cylindrical member according to claim 1 or claim 2,
A plurality of rotating members that rotatably support the cylindrical member such that an image holding body that holds a developer image and the cylindrical member are in contact with each other;
Transfer means provided on the inner side of the cylindrical member and transferring the developer image of the image carrier to the outer peripheral surface of the cylindrical member by a potential difference;
A transfer device having Developer image forming means for forming a developer image on the image carrier;
The transfer device according to claim 3, wherein the developer image of the image carrier formed by the developer image forming unit is transferred to the cylindrical member;
An image forming apparatus.

Images