JP2010186023A - Transfer device and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an electric discharge to a metallic member for guiding the conveyance of a recording material from: the rotating shaft of a rotating body to which a bias voltage for transferring an image comprising the powder of an electrified pigment to the recording material is applied; and the bearing of the rotating shaft. <P>SOLUTION: A transfer device includes: a shaft 104 supplying the bias voltage to a transfer roll 102; the bearing 105 supporting the shaft 104; and a metallic guide plate 111 guiding a paper conveyed toward the transfer roll 102, wherein a shield member 112 shielding the gap between the shaft 104 and the guide plate 111 and the gap between the bearing 105 and the guide plate 111, is arranged. At this time, the resistivity of a material constituting the shield member 112 is 10 or more times greater than the resistivity of the shaft and the bearing 105. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  Patent Document 1 describes a structure in which an insulating member is disposed at both ends of a conductive member in a conductive roller used for a transfer roll or the like. Patent Document 2 discloses a structure in which a thin elastic sheet is interposed between a conductive component and a charging roller for the purpose of preventing current leakage from the charging roller to an adjacent conductive component. ing.

JP 2001-323924 A JP 2006-11343 A

  The present invention provides a rotating shaft of a rotating body to which a bias voltage for transferring charged powder to a recording material is applied and / or a bearing of the rotating shaft to a metal member of a guide means for guiding the conveyance of the recording material. The purpose is to provide a technique for preventing discharge.

  According to the first aspect of the present invention, a rotating body to which a bias voltage for transferring charged powder is applied, a rotating shaft that supplies the bias voltage to the rotating body, and the rotating shaft are supported in a rotatable state. A bearing for supplying the bias voltage to the rotating shaft; a metal member for guiding means connected to a reference potential for guiding the recording material; and between the rotating shaft and the metal member; And a shielding member that shields electrical connection with the metal member.

  According to a second aspect of the present invention, in the first aspect of the present invention, the length of the shielding member in the axial direction of the rotating shaft is longer than the distance from the end of the rotating body to the bearing. Features.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the shielding member has a cylindrical portion having a cylindrical shape, and the rotating shaft is between the rotating body and the bearing. In the above, the cylindrical portion is inserted in a rotatable state.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the shielding member includes an extension portion that extends into a space between the rotating body and the metal member. It is characterized by.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the shielding member includes a penetrating portion that penetrates in a state where the rotating shaft is rotatable, and the penetrating portion includes The rotating shaft is attached to the bearing with the rotating shaft penetrating therethrough.

  According to a sixth aspect of the present invention, in the first aspect of the present invention, the shielding member has an opening that is open in one direction, and the rotating shaft is in the opening. It is located.

  According to a seventh aspect of the present invention, there is provided a rotating body on which an image composed of charged pigment powder is formed, and the image is transferred from the rotating body on which the image is formed to a transfer surface. An image forming apparatus comprising the transfer device according to any one of the above.

  According to the first aspect of the present invention, the conveyance of the recording material is guided from the rotating shaft of the rotating body and / or the bearing of the rotating shaft to which a bias voltage for transferring the charged powder to the recording material is applied. A technique for preventing discharge of the guiding means to the metal member is provided.

  According to invention of Claim 2, the discharge to a metal member from between a rotary body and a bearing is prevented effectively.

  According to invention of Claim 3, the discharge from a rotating shaft to a metal member is prevented effectively.

  According to invention of Claim 4, the discharge from a rotating shaft to a metal member is prevented effectively.

  According to the fifth aspect of the present invention, a simple attachment structure of the shielding member to the rotating shaft can be obtained.

  According to invention of Claim 6, a shielding member can be attached in the state in which the rotating shaft was attached to the bearing.

  According to the seventh aspect of the present invention, there is provided an image forming apparatus having the superiority according to any one of the first to sixth aspects.

It is sectional drawing which shows the cross-section of the transfer apparatus using invention. It is a top view which shows a part of transfer apparatus using invention. It is a perspective view which shows an example of a discharge prevention member. 1 is a conceptual diagram illustrating an example of an image forming apparatus using the invention. It is sectional drawing which shows the cross-section of the transfer apparatus using invention. It is a top view which shows a part of transfer apparatus using invention. It is a schematic diagram which shows an example of arrangement | positioning of a discharge prevention member. It is a perspective view which shows an example of a discharge prevention member. It is a conceptual diagram which shows an example of the mounting process of a discharge prevention member. It is a perspective view which shows an example of the mounting state of the discharge prevention member to the axis | shaft of a transfer roll. It is a perspective view which shows an example of the mounting state of the discharge prevention member to the axis | shaft of a transfer roll. They are a perspective view (A) which shows an example of a discharge prevention member, and a perspective view (B) which shows the site | part to which a discharge prevention member is attached. It is a perspective view which shows an example of the state which mounted | wore the transfer apparatus with the discharge prevention member. It is a perspective view which shows another example of a discharge prevention member. It is sectional drawing which shows a part of transfer apparatus using invention.

(1) First Embodiment FIG. 1 is a sectional view showing a part of a transfer apparatus using the invention. FIG. 2 is a top view showing a part of the transfer apparatus using the invention. FIG. 3 is a perspective view showing details of the insulating member. FIG. 2 shows a state where the photosensitive drum 101 in FIG. 1 is removed as viewed from the Z-axis direction. In FIG. 2, only the discharge preventing member 112 is shown in a cross section taken along the plane AA ′ in FIG. 1.

  FIG. 1 shows a transfer device 100. The transfer device 100 includes a photosensitive drum 101. The photosensitive drum 101 rotates in the clockwise direction in the figure. In this state, the photosensitive drum 101 is irradiated with laser light from a light source (not shown) while being scanned, so that the surface of the photosensitive drum 101 is partially exposed to form a latent image. Toner where the latent image is formed is supplied with toner as pigment powder from a developing device (not shown), and a toner image is formed on the surface of the photosensitive drum 101.

A transfer roll 102 is disposed opposite to the photosensitive drum 101. The transfer roll 102 is made of cylindrical urethane containing carbon particles. The transfer roll 102 has a structure in which a metal shaft 104 is passed through the rotation center. In this example, the thickness direction resistivity of the cylindrical urethane forming the transfer roll 102 is set to 1 × 10 ⁸ to 1 × 10 ¹⁰ Ω · m. As shown in FIG. 1, the photosensitive drum 101 is slightly sunk into the transfer roll 102 (in this example, about 2 mm), and the transfer roll 102 is deformed accordingly.

The shaft 104 is supported in a rotatable state by a resin bearing 105. The bearing 105 has a resistance value capable of transmitting a bias voltage to the shaft 104 by mixing carbon particles so that the resistivity is 1 × 10 ⁸ to 1 × 10 ¹⁰ Ω · m. A groove for receiving the shaft 104 is formed in the bearing 105, and the shaft 104 is fitted into the groove in a rotatable state by utilizing the elastic deformation of the resin constituting the shaft.

  The bearing 105 is fitted into the concave portion 107 of the resin bearing support member 106 so as to be movable up and down in the figure, and is in a state of receiving the repulsive force of the spring 108 from the bottom of the concave portion 107. The transfer roll 102 is pressed toward the photosensitive drum 101 by the repulsive force of the spring 108. The bearing support member 106 is fixed to a housing (not shown) of the image forming apparatus in which the transfer device 100 is disposed.

  The spring 107 in a compressed state is made of metal, and a bias voltage is applied from an electrode 109 provided on the bottom surface of the recess 107. Reference numeral 110 denotes a bias power supply for supplying the bias voltage. This bias voltage is, for example, about −3 to 8 kV with respect to the ground potential. The value of the bias voltage is determined by the type of toner used.

  A metal guide plate (guide member) 111 is disposed on the upstream side of the contact portion between the photoconductive drum 101 and the transfer roll 104 (upstream side in the sheet conveyance direction). The guide plate 111 is connected to a reference potential (ground potential) to prevent unintentional charging of the paper. In the figure, the guide plate 111 is directly grounded, but may be grounded via a resistor or a varistor. In addition, the guide plate 111 is made of a resin guide member instead of a metal guide plate (chute that functions as a guide member), and a metal is provided in a part of the resin guide member. The resin may protrude from a part of the metal guide member. The sheet is supplied from the right direction in FIG. 1, slides on the guide plate 111, and is conveyed toward a contact portion of the photosensitive drum 101 with the transfer roll 102. The sheet is sandwiched between the photosensitive drum 101 and the transfer roll 102, whereby the toner image on the photosensitive drum 101 is transferred onto the sheet.

  At this time, a negative bias voltage is applied to the transfer roll 102 from the bias power supply 110. By this bias voltage, an electric force that presses the charged toner (charged pigment powder) constituting the toner image to the sheet side acts, and the above-described transfer is promoted. Although not shown, the bias power supply 110 is a switching power supply, and includes a control circuit, a switching element, a transformer, a rectifier circuit, a voltage stabilization circuit, and a current stabilization circuit.

1 to 3 show the discharge preventing member 112. The discharge preventing member 112 is made of a resin material having a resistivity 10 times or more that of the shaft 104 and the bearing member 105, and has a schematic shape shown in FIG. In this case, the shaft 104 is made of metal, and the bearing 105 is a resin material containing carbon particles having a resistivity of 1 × 10 ⁸ to 1 × 10 ¹⁰ Ω · m. It is made of a material (resin material in this example) that is 10 times or more the resistivity of 105. The discharge preventing member 112 includes a cylindrical portion 112a, and is held in a state where the shaft 104 passes therethrough.

  The discharge prevention member 112 includes a vertical portion 112b, a vertical portion 112c, and an inclined portion 112d, and is configured to shield between the shaft 104 and the guide plate 111 and between the bearing 105 and the guide plate 111. The length of the discharge preventing member 112 in the direction of the shaft 104 is longer than the distance from the end of the transfer roll 102 to the bearing 105. By doing so, a portion where discharge is likely to occur is shielded by the discharge preventing member 112, and the possibility of occurrence of discharge is reduced.

  The discharge preventing member 112 includes a cylindrical portion 112a having a cylindrical shape. By storing the shaft 104 inside the cylindrical portion 112a, the discharge generated between the shaft 104 and the guide plate 111 can be effectively suppressed.

  The cylindrical portion 112a functions as a penetrating portion that penetrates the shaft 104 in a rotatable state. Since this structure can be obtained by passing the shaft 104 through the cylindrical portion 112a, assembly is easy and a simple structure can be obtained.

  Reference numeral 113 denotes a tracking roll that comes into contact with the photosensitive drum 101 at an unillustrated portion so that the interval between the photosensitive drum 101 and the transfer roll 111 is smaller than a predetermined value.

  As described above, the present embodiment includes the transfer roll 102 to which a bias voltage for transferring an image composed of charged pigment powder is applied. Further, a metal shaft 104 for supplying a bias voltage to the transfer roll 102 is provided. A shaft 105 is supported in a rotatable state, and a bearing 105 for supplying a bias voltage to the shaft 104 is provided. Further, a metallic guide plate 111 that is connected to a reference potential and guides the recording material by contacting the recording material on which an image conveyed toward the transfer roll 102 is formed is provided. Further, it has a resistivity of 10 times or more of the resistivity of the material constituting the guide plate 111 and the shaft 104, blocks between the guide plate 111 and the shaft 104, and between the bearing 105 and the guide plate 111, A discharge preventing member 112 that shields electrical connection between them and prevents discharge between them is provided.

(Example of assembly process)
Hereinafter, an example of an assembly process having the configuration shown in FIGS. 1 to 3 will be described mainly with reference to FIG. First, the transfer roll 102 to which the shaft 104 is attached is prepared. Next, the discharge preventing member 112 is attached to the shaft 104, and the tracking roll 113 is attached to the shaft 104. Then, the state shown in FIGS. 1 and 2 is obtained by pushing the shaft 104 into the groove of the bearing 105 and fitting it.

(Function of discharge prevention member)
When the transfer device is downsized, the possibility of the following phenomenon increases. Hereinafter, this point will be described by taking the configuration shown in FIGS.

  In the example described above, the potential of the bearing 105 is set to a negative potential of about −3 kV to −8 kV as compared with the potential of the guide plate 111. If the miniaturization of the transfer device 100 is pursued, the size of the gap between the bearing 105 and the guide plate 111 must be reduced accordingly.

  On the other hand, an unintended high potential difference (potential difference with respect to the ground potential) may be applied to the shaft 104 and the bearing 105 due to a failure of a device constituting the bias power supply 110 (for example, a failure of a control circuit that determines the potential). In this case, the potential difference between the shaft 104 and the guide plate 111 and the potential difference between the bearing 105 and the guide plate 111 are larger than a predetermined voltage, and there is a possibility that electric discharge occurs between them. Arise. The discharge becomes a factor that hinders normal transfer from the photosensitive drum 101 to the sheet. For example, this discharge causes the toner image transferred on the paper to be disturbed. In addition, the components are damaged.

  1-3, the discharge prevention member 112 is positioned between the bearing 105 and the guide plate 111, and further between the shaft 104 and the guide plate 111, and functions as a shielding member. The occurrence of the discharge is suppressed as compared with the case where the member 112 is not provided. For this reason, generation | occurrence | production of the bad influence resulting from said discharge is suppressed. In addition, since the above-described discharge can be suppressed even if the device is downsized, further downsizing of the device can be pursued. Furthermore, the freedom degree of the position which arrange | positions the guide plate 111 becomes high.

(2) Second Embodiment An example of an image forming apparatus using the present invention will be described. FIG. 4 is a conceptual diagram showing an example of an image forming apparatus using the invention. FIG. 4 shows the image forming apparatus 10. The image forming apparatus 10 includes a paper storage device 11. The sheet storage device 11 stores a plurality of sheets. The paper stored in the paper storage device 11 is pulled out to the transport path 12 by a transport roll (not shown) and sent to the transfer device 13.

  The transfer device 13 has the same configuration as the transfer device 100 shown in FIGS. FIG. 4 shows a cleaning roll 31, a charging device 32, a laser beam irradiation device 33 and a developing device 34 for performing photosensitivity, which are not shown in FIGS. 1 and 2.

  The cleaning roll 31 removes unnecessary toner remaining on the surface of the photosensitive drum 101. The charging device 32 charges the surface of the photosensitive drum 101 to a negative potential. The laser light irradiation device 33 irradiates the photoconductive drum 101 with laser light that serves as drawing light for forming a latent image on the surface of the photoconductive drum 101. The laser beam irradiation device 33 includes an optical system that scans and irradiates laser light and a laser beam generator. The developing device 34 includes a container that stores toner, and a toner supply roll 34 a that supplies toner to the photosensitive drum 101.

  Transfer devices 14 to 16 are sequentially arranged on the downstream side of the transfer device 13. The transfer devices 14 to 16 have the same configuration as the transfer device 13. In this example, the CMYK four-color basic toner images are sequentially transferred onto the paper in the transfer devices 13 to 16. Here, C is cyan, M is magenta, Y is yellow, and K is black.

  In the transfer devices 13 to 16, the paper on which the toner images of the respective basic colors are formed is sent to the fixing device 17. The fixing device 17 includes a heating roll 18 having a built-in heater and a pressure roll 19, and heat and pressure are applied with a sheet sandwiched between both rolls. As a result, the unfixed toner image on the paper is fixed on the paper, and a fixed image is obtained. The paper for which the fixing process has been completed is discharged onto the paper discharge surface 20.

  The structure of the discharge preventing member in the transfer device 13 is not limited to the structure illustrated in FIGS. 1 to 3, and other forms described later can be used.

(3) Third Embodiment An example of another shape of the discharge preventing member 112 in the first embodiment will be described. FIG. 5 is a cross-sectional view showing a part of a transfer apparatus using the invention. FIG. 6 is a top view showing a part of the transfer apparatus using the invention. FIG. 7 is a perspective view showing details of the discharge preventing member. FIG. 6 shows a state in which the photosensitive drum 101 in FIG. 5 is removed as viewed from the Z-axis direction. In FIG. 6, only the discharge preventing member 121 is shown in a cross-section taken along the plane AA ′ of FIG. Note that members other than the discharge prevention member 121 are the same as those in the first embodiment described with reference to FIGS.

  6 and 7 show the discharge preventing member 121. The discharge preventing member 121 has a structure in which a portion 121b is added to the discharge preventing member 112 of FIG. The portion denoted by reference numeral 121 b extends in the direction of the transfer roll 102 and extends between the transfer roll 102 and the guide plate 111. According to this structure, the portion 121b is positioned between the transfer roll 102 and the guide plate 111. Therefore, the shielding performance between the shaft 104 or the bearing 105 and the guide plate 111 is higher than that shown in FIGS. 1 to 3, and discharge between the shaft 104 or the bearing 105 and the guide plate 111 is prevented. The function becomes even higher.

  That is, in the example shown in FIG. 6, the discharge preventing member 112 serves as a shielding member, and the guide plate 111 cannot be seen through the shaft 104 and the bearing 105. Since the discharge mainly occurs between the members that can see each other, it is possible to effectively suppress the discharge by shielding the members that may cause the discharge from being seen.

(4) Fourth Embodiment FIG. 8 is a perspective view showing an example of a discharge preventing member. FIG. 8 shows the discharge preventing member 201. The discharge preventing member 201 includes a side plate 202a and a side plate 202a. The discharge preventing member 201 includes an upper surface member 203 and an upper shielding member 204 having a curved shape that covers the shaft from above. The discharge preventing member 201 is provided with an opening 205, and a shaft (for example, the shaft 104 in FIG. 2) is passed through the opening 205. The arrangement state and material of the discharge preventing member 201 are the same as those of the discharge preventing member 112 shown in FIG.

  FIG. 9 is a conceptual diagram showing an example of a process for attaching the discharge preventing member 201 to the transfer device. First, the transfer roll 102 to which the shaft 104 is attached and the discharge preventing member 201 are prepared (FIG. 9A). Next, the discharge preventing member 201 is attached to the shaft 104 (FIG. 9B). FIG. 10 shows a state where the discharge preventing member 201 is attached to the shaft 104. When the state shown in FIG. 9B is obtained, the shaft 104 is pushed into the groove of the bearing 105 to obtain the state shown in FIG. This state is shown in FIG.

(5) Fifth Embodiment FIG. 12 is a perspective view showing an example of the discharge preventing member of the embodiment. FIG. 12A is a perspective view illustrating an example of a discharge preventing member, and FIG. 12B is a perspective view illustrating a portion of a transfer device to which the discharge preventing member is attached. FIG. 12 shows a discharge prevention device 301. The discharge prevention member 301 has a box shape in which the lower surface side in the figure is opened.

  The discharge preventing member 301 is made of a resin material having a resistivity of 10 times or more than the resistivity of the material constituting the bearing 401 described later. The discharge prevention member 301 includes a curved upper surface portion 301 having a curved shape covering the upper side of the shaft 104. Both sides of the curved upper surface portion are flat upper surface portions 302 and 303. The side surface of the discharge preventing member 301 includes a side surface portion 304. The side surface portion 304 is provided with a receiving portion 305 having a slit structure that meshes with the guide portion 402 of the bearing 401. The receiving portion 305 has a groove-like structure extending in the vertical direction in the figure. These structures are the same on the side surface (not shown). FIG. 12 shows a receiving portion 306 having the same function as the receiving portion 305.

  Vertical portions 308 and 309 are provided before and after the discharge preventing member 301 in the axial direction. The vertical portion 308 is provided with an opening 310 that receives the shaft 104. The opening 310 is open at the bottom of the figure, and has an upper portion along the outer periphery of the shaft 104. In the vertical portion 309, an opening (not shown) similar to the opening 310 is formed.

FIG. 12B shows a state where the shaft 104 is attached to the bearing 401 in a rotatable state. The bearing 401 is made of a resin in which carbon particles are mixed so that the resistivity is 1 × 10 ⁸ to 1 × 10 ¹⁰ Ω · m. A groove for receiving the shaft 104 is formed in the bearing 401, and the shaft 104 is fitted into the groove in a rotatable state by utilizing the elastic deformation of the resin constituting the shaft.

  On both side surfaces of the bearing 401, rail-shaped guide portions 402 and 403 having a rectangular cross section are provided. The guide portions 402 and 403 are used when a bearing is attached to a bearing support member (not shown). That is, the bearing support member (not shown) is provided with a receiving portion for receiving the guide portions 402 and 403. By fitting (meshing) the guide portions 402 and 403 into the receiving portion, the bearing support for the bearing 401 is provided. Attachment to the member is performed.

  FIG. 13 is a perspective view showing a state in which the discharge preventing member 301 is attached to the portion shown in FIG. In FIG. 13, the portion of the transfer roll to which the shaft 104 is attached is not shown. As shown in FIG. 13, the discharge preventing member 301 is attached from above the shaft 104. In this structure, the discharge prevention member 301 is attached to the bearing 401 by engaging the guide portion 402 with the receiving portion 305. Although not shown in the figure, the guide portion 403 in FIG.

  The structure shown in FIG. 13 is obtained by covering the discharge preventing member 301 shown in FIG. 12 (A) over the portion shown in FIG. 3 (B) from above. For this reason, it does not take time to attach the discharge preventing member 301. The structure of the present embodiment can be used when retrofitting a discharge prevention member to an existing structure, in addition to being applied to a structure in which it is assumed that the discharge prevention member 301 is attached in advance. In this case, the detailed shape of the discharge preventing member 301 may be changed in accordance with the structure and shape of the transfer device to be applied.

  A claw portion may be formed inside the discharge prevention member 301, and a receiving portion that meshes with the claw portion may be formed on the bearing 401. According to this configuration, when the discharge preventing member 301 is pushed in and attached from above the bearing 401, the claw portion and the receiving portion are engaged with each other, and a state in which the discharge preventing member 301 is attached to the bearing 401 is obtained. For this reason, the effort which attaches the discharge prevention member 301 is simplified.

(6) Sixth Embodiment FIG. 14 is a perspective view showing another example of the discharge preventing member. FIG. 14A shows the discharge preventing member 400. The discharge preventing member 400 can be used in place of the discharge preventing member 112 in FIGS. 1 and 2. The discharge prevention member 400 includes shielding portions 401a and 401b on the side portion of the guide plate 111 that is one of objects to be discharged, and the other side portion has an open structure. The discharge preventing member 400 includes a cylindrical portion (sleeve portion) 402 through which a shaft passes.

  FIG. 14B shows the discharge preventing member 410. The discharge prevention member 410 is a modification of the shape of the discharge prevention member 400, and includes shielding portions 411a and 411b on the side of the guide plate (not shown), and the other side has an open structure. Reference numeral 412 denotes an opening through which a shaft (not shown) passes.

(7) Seventh Embodiment FIG. 15 shows an example of discharge preventing means that can be used in place of the discharge preventing member 112 in the configuration illustrated in FIGS. FIG. 15 shows a discharge prevention member 431 having a cylindrical shape (sleeve shape). The discharge prevention member 431 covers a part of the bearing 430 and a part of the shaft 104. The bearing 430 is made of a resin material mixed with carbon particles so that the resistivity is 1 × 10 ⁸ to 1 × 10 ¹⁰ Ω · m, and has the same shape as the bearing 105 shown in FIG. . The discharge prevention member 431 is made of a resin material having a resistivity 10 times or more than that of the bearing 430. The discharge prevention member 431 supports the shaft 104 integrally with the bearing 430.

  One end of the discharge preventing member 431 is processed into a shape that accommodates the bearing 430. The bearing support member 106 is provided with a notch for receiving the discharge preventing member 431. The discharge prevention member 431 having a cylindrical shape is passed through the shaft 104 and contacts the inside of the notch of the bearing support member 106 in a state where the bearing 430 is accommodated at one end. In this structure, the discharge preventing member 431 also functions as a bearing.

  Also in this structure, the discharge preventing member 431 shields between the bearing 430 and the guide plate 111 and further between the shaft 104 and the guide plate 111. For this reason, discharge between the bearing 430 and the guide plate 111 and further discharge between the shaft 104 and the guide plate 111 are prevented.

  The present invention can be applied to a transfer device of an image forming apparatus.

  DESCRIPTION OF SYMBOLS 101 Photosensitive drum, 102 ... Transfer roll, 104 ... Shaft, 105 ... Bearing, 106 ... Bearing support member, 107 ... Recessed part, 108 ... Spring, 109 ... Electrode, 110 ... Bias power supply, 111 ... Guide plate, 112 ... Discharge prevention Member, 112a ... cylindrical portion, 113 ... tracking roll.

Claims (7)

A rotating body to which a bias voltage for transferring charged powder is applied;
A rotating shaft for supplying the bias voltage to the rotating body;
A bearing that supports the rotating shaft in a rotatable state and supplies the bias voltage to the rotating shaft;
A metal member that is connected to a reference potential and guides the recording material;
A transfer device comprising: a shielding member that shields electrical connection between the rotating shaft and the metal member and between the bearing and the metal member.   The transfer device according to claim 1, wherein a length of the shielding member in an axial direction of the rotation shaft is longer than a distance from an end of the rotation body to the bearing. The shielding member has a cylindrical portion having a cylindrical shape,
The transfer device according to claim 1, wherein the rotating shaft is inserted between the rotating body and the bearing so as to be rotatable inside the cylindrical portion.   The transfer device according to claim 1, wherein the shielding member includes an extension portion that extends into a space between the rotating body and the metal member. The shielding member includes a penetrating portion that penetrates the rotating shaft in a rotatable state.
The transfer device according to claim 1, wherein the rotary shaft is attached to the bearing in a state where the rotary shaft passes through the penetrating portion.   The transfer device according to claim 1, wherein the shielding member has an opening that is open in one direction, and the rotation shaft is positioned in the opening. A rotating body on which an image composed of charged pigment powder is formed;
An image forming apparatus comprising: the transfer device according to claim 1, wherein the image is transferred from a rotating body on which the image is formed to a transfer surface.

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