Patent Publication Number: US-11656563-B2

Title: Jacket, transfer device, and image forming device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of International Application No. PCT/JP2020/019966 filed on May 20, 2020, and claims priority from Japanese Patent Application No. 2019-148712 filed on Aug. 14, 2019. 
    
    
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a jacket, a transfer device, and an image forming device. 
     Related Art 
     A technique of winding a replaceable jacket around a transfer cylinder and transferring an image onto a sheet passing over the jacket is considered. 
     Patent Literature 1 discloses an intermediate transfer member in which a replaceable sheet-shaped bracket is wound around a drum corresponding to a transfer cylinder to transfer a toner layer onto the bracket. 
     CITATION LIST 
     Patent Literature 
     
         
         Patent Literature 1: JP-A-2004-171022 
       
    
     SUMMARY 
     In the bracket in Patent Literature 1 described above, a toner image is directly transferred onto the bracket, and the toner image transferred onto the bracket is further transferred onto another member from the bracket. On the other hand, here, a sheet is placed on a jacket (bracket), and an image such as the toner image is to be formed on the sheet. 
     Although the bracket in Patent Literature 1 is attached to and detached from the drum, Patent Literature 1 does not refer to workability in attachment and detachment. 
     Aspects of non-limiting embodiments of the present disclosure relate to providing a jacket having improved workability in attachment and detachment as compared with a jacket in which an end edge of a layer having high hardness is exposed, and a transfer device and an image forming device including the jacket. 
     Aspects of certain non-limiting embodiments of the present disclosure address the above advantages and/or other advantages not described above. However, aspects of the non-limiting embodiments are not required to address the advantages described above, and aspects of the non-limiting embodiments of the present disclosure may not address advantages described above. 
     According to an aspect of the present disclosure, there is provided a jacket including: 
     a first layer that is on a cylinder body side when the jacket is attached to a rotating cylinder body; and 
     a second layer that is a layer located on a side opposite to the cylinder body with the first layer interposed therebetween, has a hardness lower than that of the first layer, and does not exist at a position where at least one of end edges of the body in a rotation axis direction is located inward of the first layer in the rotation axis direction. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       Exemplary embodiment(s) of the present invention will be described in detail based on the following figures, wherein: 
         FIG.  1    is a schematic diagram showing an outline of an image forming device according to one exemplary embodiment of the present disclosure; 
         FIG.  2    is a schematic perspective view showing a periphery of a transfer cylinder; 
         FIG.  3    is a schematic cross-sectional view of the transfer cylinder with a jacket attached, which is shown in a cross section in a plane perpendicular to a rotation shaft; 
         FIG.  4    is a schematic cross-sectional view of the jacket in a width direction, showing the jacket in a first example in a cross section taken along a plane extending in a rotation axis direction; and 
         FIG.  5    is a schematic cross-sectional view of the jacket in the width direction, showing the jacket in a second example in the cross section taken along the plane extending in the rotation axis direction. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, exemplary embodiments of the present disclosure will be described. 
       FIG.  1    is a schematic diagram showing an outline of an image forming device according to one exemplary embodiment of the present disclosure. The image forming device includes a transfer device and a jacket according to one exemplary embodiment of the present disclosure. The jacket is a consumable item and is detachable. 
     An image forming device  10  is a type of electrophotographic image forming device that forms an image using a dry toner. 
     The image forming device  10  includes four image carriers  20 Y,  20 M,  20 C, and  20 K. Each of the image carriers  20 Y,  20 M,  20 C, and  20 K forms a toner image on a surface thereof while rotating in a direction of an arrow A. Here, reference numerals Y, M, C, and K among the reference numerals  20 Y,  20 M,  20 C, and  20 K of the image carriers represent colors to be formed of the toner. In the following description, the reference signs Y, M, C, and K are omitted for common description regardless of the color of the toner. The same applies to components other than the image carrier  20 . 
     The image forming device  10  further includes an intermediate transfer belt  30 . The intermediate transfer belt  30  is an endless belt wound around plural rollers  31 ,  32 , and  33  including the secondary transfer roller  31  and circularly moves in a direction of an arrow B. The toner images formed on the image carriers  20  are sequentially transferred onto the intermediate transfer belt  30  in an overlapping manner by an action of primary transfer rollers  21 . 
     The image forming device  10  includes a transfer cylinder  40  and a fixing cylinder  50 . Here, the transfer cylinder  40  is provided at a position facing the secondary transfer roller  31  with the intermediate transfer belt  30  interposed therebetween. The fixing cylinder  50  has a rotation axis parallel to a rotation axis of the transfer cylinder  40 , and is disposed at a position separated from the transfer cylinder  40  in a horizontal direction. A fan  60  and a heater  70  are disposed between the transfer cylinder  40  and the fixing cylinder  50 . The transfer cylinder  40  and the fixing cylinder  50  are examples of a cylinder body. 
       FIG.  2    is a schematic perspective view showing a periphery of the transfer cylinder. 
     Gears  41  fixed to a rotation shaft  401  of the transfer cylinder  40  are provided on both sides of the transfer cylinder  40 , and chains  42  mesh with the gears  41 . Gears similar to those of the transfer cylinder  40  are also fixed to both sides of the rotation shaft of the fixing cylinder  50  shown in  FIG.  1   . Each chain  42  has an endless shape and is wound around the gear  41  of the transfer cylinder  40  and the gear (not shown) of the fixing cylinder  50 . The transfer cylinder  40 , the chains  42 , and the fixing cylinder  50  are driven by a drive source (not shown) so that the chains  42  circulate in a direction of arrows C. 
     A gripper  43  is bridged between the chains  42 , and both end portions of the gripper  43  are attached to the chains  42 . A function of the gripper  43  will be described later. Since the gripper  43  is attached to the chains  42 , when the chains  42  circulate in the direction of the arrows C, the gripper  43  moves from the transfer cylinder  40  to the fixing cylinder  50  and returns from the fixing cylinder  50  to the transfer cylinder  40  in accordance with movement of the chains  42 . A groove  402  extending in the rotation axis direction is formed in the transfer cylinder  40 . When the gripper  43  is located at a position overlapping the transfer cylinder  40 , the gripper  43  enters the groove  402 . A groove  502  (see  FIG.  1   ) similar to the groove  402  of the transfer cylinder  40  is also formed in the fixing cylinder  50 . When the gripper  43  is located at a position overlapping the fixing cylinder  50 , the gripper  43  enters the groove  502 . 
       FIG.  3    is a schematic cross-sectional view of the transfer cylinder  40  with a jacket  90  attached, which is shown in a cross section taken in a plane perpendicular to the rotation axis of the transfer cylinder  40 . 
     The jacket  90  is attached to the transfer cylinder  40 . Both end portions  901  of the jacket  90  in a rotation direction of the transfer cylinder  40  are bent and enter the groove  402 , and are fixed to wall surfaces of the groove  402 . The transfer cylinder  40  is a conductive metal member. The jacket  90  is also conductive. The jacket  90  is a consumable item that may be replaced from time to time. 
     The description will be continued returning to  FIGS.  1  and  2   . 
     A sheet P is sent out from a sheet tray (not shown), transported in a direction of an arrow D by a transport device  80 , and guided to the transfer cylinder  40 . Phases of transport of the sheet P and rotation of the transfer cylinder  40  are synchronized with each other. A front end portion of the transported sheet P is grasped by the gripper  43 . The sheet P grasped by the gripper  43  is first wound around the transfer cylinder  40  (on the jacket  90  attached to the transfer cylinder  40 ) in accordance with the rotation of the transfer cylinder  40  and the movement of the chains  42 . A timing of the transport of the sheet P and the transfer of the toner image onto the intermediate transfer belt  30  is also adjusted. The toner image transported by the intermediate transfer belt  30  is transferred onto the sheet P in a state of being wound around the transfer cylinder  40  by the action of the secondary transfer roller  31 . 
     The sheet P to which the toner image is transferred is transported toward the fixing cylinder  50  along with the movement of the chains  42  while the front end portion of the sheet P is grasped by the gripper  43 . Here, the fan  60  is disposed below a height through which the gripper  43  passes, and has a function of sending air toward the sheet P and maintaining the sheet P in a floating state. The heater  70  is disposed above the height through which the gripper  43  passes, and preheats the sheet P and the toner image. Here, if the sheet P is not in the floating state but in a state where a lower surface thereof is in contact with a member, ways the heat is applied differs between a place where the sheet P is in contact and a place where the sheet P is not in contact, and there is a concern that unevenness may occur in the image. For this reason, here, the fan  60  is provided to send the air, and the sheet P is maintained in the floating state. 
     A fixing roller  51  in which a heat source  511  is disposed is provided at a position adjacent to the fixing cylinder  50 . The sheet P transported to the fixing cylinder  50  while being grasped by the gripper  43  is interposed between the fixing cylinder  50  and the fixing roller  51 , and is heated and pressurized, so that an image formed of a fixed toner image is formed on the sheet P. If the toner image on the sheet P is to be fixed only by the fixing cylinder  50  and the fixing roller  51  without providing the heater  70 , since it is necessary to increase the heating and pressurization by the fixing cylinder  50  and the fixing roller  51 , a distribution of pressurization strength in the rotation axis direction may occur, and the sheet P may be wrinkled. Therefore, here, preheating is performed by providing the heater  70 . 
     The sheet P, on which the toner image is fixed by being interposed between the fixing cylinder  50  and the fixing roller  51  and being heated and pressurized, is released from the gripper  43  grasping the front end portion of the sheet P, and is sent out to the outside of the image forming device  10  along a transport path (not shown). On the other hand, the gripper  43  moves together with the movement of the chains  42  and returns to the transfer cylinder  40  again. 
     Next, a layer structure of the jacket will be described. 
       FIG.  4    is a schematic cross-sectional view of the jacket in a width direction, showing the jacket in a first example in a cross section taken along a plane extending in the rotation axis direction. 
     The jacket  90  has a laminated structure in which a base layer  91 , an adhesive layer  92  (for example, an acrylic conductive adhesive), an elastic layer  93 , and a surface layer  94  are laminated in this order. Here, in the jacket  90 , the base layer  91  is a layer made of metal, and each layer is formed of a conductive material. Therefore, it is possible to form a transfer electric field by attaching the jacket  90  to the conductive transfer cylinder  40  made of metal or the like. 
     The base layer  91  serves to maintain a shape of the jacket  90  so that the entire jacket  90  does not extend even when the jacket  90  is attached to the transfer cylinder  40  or the jacket  90  is pressed against the secondary transfer roller  31  via the intermediate transfer belt  30 . The elastic layer  93  is a layer that appropriately expands or contracts in a thickness direction when the jacket  90  is pressed against the secondary transfer roller  31  via the intermediate transfer belt  30  to smoothly transfer the toner image onto the sheet P. The surface layer  94  serves to protect the elastic layer  93 . 
     The base layer  91  is a layer made of a thin metal plate. The base layer  91  is formed of, for example, stainless steel having a thickness of about 50 μm or copper or aluminum having a thickness of about 100 μm. The base layer  91  is a layer on a transfer cylinder  40  side when the base layer  91  is attached to the transfer cylinder  40 , and corresponds to an example of a first layer according to the present disclosure. When the base layer  91  is constituted by stainless steel, corrosion resistance is excellent and corrosion is less likely to occur as compared with a case where the base layer  91  is constituted by a metal material other than stainless steel. 
     The elastic layer  93  is located on a side opposite to the transfer cylinder  40  via the base layer  91 , is a rubber layer having a thickness of about 5 to 7 mm and has a hardness lower than that of the base layer  91 . The elastic layer  93  may be a rubber layer made of foamed rubber. For example, a conductive resin material (conductive rubber layer) such as nitrile rubber, chloroprene rubber, ethylene propylene diene rubber (EPDM), acrylonitrile butadiene rubber (NBR), silicon rubber, polyurethane, polyethylene, or a mixture thereof is used for the elastic layer  93 . The foamed rubber does not have good adhesion. However, in the first example, since the foamed rubber is adhered to the base layer  91  in advance, even if the elastic layer  93  is formed of the foamed rubber, the foamed rubber may be wound around the transfer cylinder  40 . 
     The elastic layer  93  has at least one of end edges in the rotation axis direction of the transfer cylinder  40 , for example, both end edges  931  and  932  in the example shown in  FIG.  4   , that does not exist at a position located inward of the base layer  91  in the rotation axis direction. Alternatively, at least one of end edges of the elastic layer  93  in the rotation axis direction, for example, both end edges  931  and  932  in the example shown in  FIG.  4   , is located at positions protruding outward from the base layer  91  in the rotation axis direction. The elastic layer  93  in  FIG.  4    corresponds to an example of a second layer according to the present disclosure. Here, a thickness of the base layer  91  is smaller than a thickness of the elastic layer  93 . Therefore, as compared with the case where the thickness of the base layer  91  is equal to or larger than the thickness of the elastic layer  93 , even the base layer  91  having large hardness may be easily wound around the transfer cylinder  40 , and workability in attachment and detachment of the jacket  90  is improved. 
     In the case of the jacket  90  in the first example, as described above, the base layer  91  is thinner than the elastic layer  93 , and is formed of, for example, stainless steel having the thickness of about 50 μm or copper having the thickness of about 100 μm. Therefore, the end edges  911  and  912  of the base layer  91  may be sharp blades. 
     In the case of the jacket  90  in the first example, the base layer  91  made of metal and having high hardness does not protrude from the elastic layer  93  in the rotation axis direction. When the base layer  91  protrudes from the elastic layer  93 , the workability is reduced. However, in the case of the first example, the base layer  91  does not protrude from the elastic layer  93 , and therefore, even under a condition in which the base layer  91  itself may be the sharp blade, the workability when attaching and detaching the jacket  90  to and from the transfer cylinder  40  is improved. 
     In particular, according to the jacket  90  in the first example, since the end edges  931  and  932  of the elastic layer  93  protrude from the base layer  91  in the rotation axis direction, the workability in attachment and detachment is further improved as compared with the case where the end edges  911  and  912  of the base layer  91  and the end edges  931  and  932  of the elastic layer  93  overlap each other. 
     The surface layer  94  is laminated on the elastic layer  93  interposed between the base layer  91  and the surface layer  94 . The surface layer  94  is made of, for example, polyimide or polyamide-imide, and has a thickness of about 80 to 100 μm. At least one of end edges of the surface layer  94  in the rotation axis direction does not exist at a position inward of the elastic layer  93  in the rotation axis direction. Further, at least one of end edges of the surface layer  94  in the rotation axis direction, for example, both end edges  941  and  942  in the case of the first example shown here, is located at a position protruding outward from the elastic layer  93  in the rotation axis direction. As described above, since the end edges  941  and  942  of the surface layer  94  do not exist at the positions inward of the elastic layer  93 , it is difficult to directly touch the elastic layer  93 , and the elastic layer  93  is protected by the surface layer  94 . In particular, in the case of the first example, since the end edges  941  and  942  of the surface layer  94  protrude from the elastic layer  93 , protection of the elastic layer  93  by the surface layer  94  is improved as compared with the case where the end edges  941  and  942  of the surface layer  94  and the end edges  931  and  932  of the elastic layer  93  overlap each other. 
     The adhesive layer  92  that adheres the base layer  91  and the elastic layer  93  does not exist outward from the base layer  91  in the rotation axis direction. In the case of the first example shown in  FIG.  4   , at least one of end edges in the rotation axis direction, specifically, both end edges  921  and  922 , is located inward of the base layer  91  in the rotation axis direction. As described above, since the adhesive layer  92  does not exist outward from the base layer  91  in the rotation axis direction, the adhesive layer  92  is prevented from directly touching the transfer cylinder  40 . In the case of the first example, since both end edges  921  and  922  are located inward of the base layer  91  in the rotation axis direction, the adhesive layer  92  is further prevented from directly touching the transfer cylinder  40  as compared with the case where the end edges  911  and  912  of the base layer  91  and the end edges  921  and  922  of the adhesive layer  92  overlap each other. 
     Next, a second example of the jacket will be described. 
       FIG.  5    is a schematic cross-sectional view of the jacket in the width direction, showing the jacket in the second example in the cross section taken along the plane extending in the rotation axis direction. Also in the second example, elements corresponding to the elements in the first example shown in  FIG.  4    are denoted by the same reference numerals as those used in  FIG.  4   . 
     As in the first example, the jacket  90  in the second example has a laminated structure in which the base layer  91 , the adhesive layer  92 , the elastic layer  93 , and the surface layer  94  are laminated in this order. Here, each layer constituting the jacket  90  is formed of the same conductive material as each layer in the first example. Therefore, it is possible to form a transfer electric field by attaching the jacket  90  to the conductive transfer cylinder  40  made of metal or the like. The thickness of each layer is the same as that in the first example. 
     In the case of the jacket  90  in the second example, similarly to the first example, the base layer  91  corresponds to an example of the first layer according to the present disclosure. However, in the case of the jacket  90  in the second example, unlike the first example, the surface layer  94  is regarded as an example of the second layer according to the present disclosure. 
     In the case of the jacket  90  in the second example, the surface layer  94 , which is an example of the second layer, has at least one of end edges in the rotation axis direction of the transfer cylinder  40 , for example, both end edges  941  and  942  in the example shown in  FIG.  5   , that does not exist at a position located inward of the base layer  91  in the rotation axis direction. Alternatively, at least one of end edges of the surface layer  94  in the rotation axis direction, for example, both end edges  941  and  942  in the example shown in  FIG.  5   , is located at a position protruding outward from the base layer  91  in the rotation axis direction. 
     In the case of the jacket  90  in the second example, similarly to the first example, the base layer  91  is formed of, for example, stainless steel having the thickness of about 50 μm or copper having the thickness of about 100 μm. Therefore, the end edges  911  and  912  of the base layer  91  may be sharp blades. In the case of the jacket  90  in the second example, the base layer  91  made of metal and having high hardness does not protrude from the surface layer  94  in the rotation axis direction. Therefore, even under the condition in which the base layer  91  itself may be the sharp blade, the workability when attaching and detaching the jacket  90  to and from the transfer cylinder  40  is improved. 
     Here, the elastic layer is interposed between the surface layer  94  and the base layer  91 . At least one of end edges of the surface layer  94  in the rotation axis direction does not exist at a position inward of the elastic layer  93  in the rotation axis direction. Therefore, the elastic layer  93  is protected by the surface layer  94  at the end edge on the side where the end edge of the surface layer does not exist at the position inward of the elastic layer  93  in the rotation axis direction. Further, according to the second example, at least one of end edges of the surface layer  94  in the rotation axis direction, specifically, both end edges  941  and  942 , is located at positions protruding outward from the elastic layer  93  in the rotation axis direction. Therefore, according to the jacket  90  in the second example, the protection of the elastic layer  93  by the surface layer  94  is improved as compared with the case where the end edges  941  and  942  of the surface layer  94  and the end edges  931  and  932  of the elastic layer  93  overlap each other in the rotation axis direction. 
     In the second example, regarding the adhesive layer  92  that adheres the base layer  91  and the elastic layer  93 , the end edges  921  and  922  of the adhesive layer  92  in the rotation axis direction do not exist outward from the base layer  91  and do not exist inward of the elastic layer  93 . Therefore, the adhesive layer  92  is prevented from directly touching the transfer cylinder  40 , and the adhesive layer  92  is adhered to the base layer  91  up to the end edges  931  and  932  of the elastic layer  93  in the rotation axis direction. In the case of the second example, at least one of end edges of the adhesive layer  92  in the rotation axis direction, that is, both end edges  921  and  922  in the example shown in the second example, is located inward of the base layer  91  in the rotation axis direction and at a position protruding from the elastic layer  93 . Therefore, as compared with the case where the end edges  911  and  912  of the base layer  91  and the end edges  921  and  922  of the adhesive layer  92  overlap each other, the adhesive layer  92  is further prevented from directly touching the transfer cylinder  40 , and as compared with the case where the end edges  921  and  922  of the adhesive layer  92  and the end edges  931  and  932  of the elastic layer  93  overlap each other in the rotation axis direction, adhesiveness of the elastic layer  93  to the base layer  91  is further increased up to the end edges  931  and  932  of the elastic layer  93  in the rotation axis direction. 
     In the first and second examples described above, the adhesive layer  92  and the elastic layer  93  are laminated between the base layer  91  and the surface layer  94 . However, one or plural other layers such as another elastic layer may be provided between the base layer  91  and the surface layer  94  in addition to the adhesive layer  92  and the elastic layer  93 . The base layer  91  and the elastic layer  93  may be adhered to each other by thermally melting between the base layer  91  and the elastic layer  93  without providing the adhesive layer  92 . In the first example described above, the surface layer  94  is laminated on the elastic layer  93 , whereas the surface layer  94  may not be laminated. 
     As described above, in the case of the first example shown in  FIG.  4   , the elastic layer  93  as the second layer protrudes from the base layer  91  as the first layer in the rotation axis direction. Therefore, as compared with the case where the base layer  91  protrudes, higher workability is ensured during the work of attaching and detaching the jacket  90  to and from the transfer cylinder  40 . In the case of the second example shown in  FIG.  5   , the surface layer  94  as the second layer protrudes from the base layer  91  as the first layer in the rotation axis direction. Therefore, as compared with the case where the base layer  91  protrudes, higher workability is ensured during the work of attaching and detaching the jacket  90  to and from the transfer cylinder  40 . 
     Although the jacket used in the electrophotographic image forming device is described as an example, a theme of the jacket according to the present disclosure is the workability at the time of attaching and detaching. The present disclosure may be applied to a jacket used in, for example, an inkjet image forming device other than the electrophotographic image forming device. Further, the present disclosure may be applied to a jacket wound around the fixing cylinder  50 . 
     Further, the base layer  91  as the first layer and the elastic layer  93  or the surface layer  94  as the second layer may have the same length in the rotation axis direction so that the end edge of the base layer  91  is not exposed. However, in order to more reliably prevent the end edge of the base layer  91  from being exposed, the second layer may protrude from the first layer in the rotation axis direction as in the first example shown in  FIG.  4    and the second example shown in  FIG.  5   . 
     The foregoing description of the exemplary embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.