JP2019040157A - Image holding body, image forming unit, and image forming apparatus - Google Patents

Abstract

To obtain an image holding body that is configured such that a pressing part is pressed against an inner peripheral surface of a substrate having a thickness of 0.4 mm, and can adjust the circularity of an outer peripheral surface of the substrate against which the pressurizing part is pressed to 40 μm or less; an image forming unit; and an image forming apparatus.SOLUTION: A substrate 80 is made of aluminum, has a cylindrical shape, and has a thickness of 0.4 mm. An ear part 66B is pressed against an inner peripheral surface 80A of the substrate 80 with a pressing force of 5.0 N or less.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an image carrier, an image forming unit, and an image forming apparatus.

  The electrophotographic photosensitive member described in Patent Document 1 has a resin flange, a central shaft hole into which a shaft is inserted to rotatably support the photosensitive drum, and electrical conduction between the photosensitive drum and the shaft. And a ground plate attached to the resin flange.

JP 2005-134625 A

  The image carrier has a cylindrical aluminum base material, a photosensitive layer formed on the outer peripheral surface of the base material, and a metal pressing portion. The pressing portion is pressed against the inner peripheral surface of the base material.

  Here, in order to reduce the cost of the base material, the thickness of the base material may be reduced. Specifically, the thickness of the base material may be reduced from 0.7 [mm] to 0.4 [mm]. When the thickness of the substrate is 0.7 [mm] or more, the pressing portion is pressed even if the pressing force pressing the pressing portion against the inner peripheral surface of the substrate is 6.0 [N] or more. The deformation of the substrate of the part was small. However, if the thickness of the substrate is reduced, the deformation of the substrate at the portion where the pressing portion is pressed increases.

  The subject of this invention is the structure which presses a pressing part to the internal peripheral surface of a base material with thickness 0.4 [mm], and the roundness of the outer peripheral surface of the base material of the part into which the press part is pressed is 40 [ μm] or less.

  An image carrier according to claim 1 of the present invention is an aluminum cylinder having a thickness of 0.4 [mm] and an inner peripheral surface of the substrate of 5.0 [N] or less. The pressing portion is pressed with the pressing force, and the photosensitive layer is formed on the outer peripheral surface of the base material.

  An image carrier according to a second aspect of the present invention is the image carrier according to the first aspect, wherein the image carrier is attached to an end portion of the base material, closes an opening of the base material, and supports the pressing portion. An adhesive that adheres the blocking portion to the base material is applied to a portion of the inner peripheral surface of the base material where the pressing portion is pressed, and the pressing portion is 0 It is pressed against the inner peripheral surface of the base material with a pressing force of 5 [N] or more.

  An image carrier according to a third aspect of the present invention is the image carrier according to the first or second aspect, wherein the image carrier is pressed against the inner peripheral surface of the base material at the pressing portion when viewed from the axial direction of the base material. The pressing portion has a curved shape protruding toward the base material side.

  An image carrier according to a fourth aspect of the present invention is the image carrier according to the third aspect, wherein the pressing portion has a radius of the inner peripheral surface of the base material when viewed from the axial direction of the base material. It is characterized by being the same.

  An image carrier according to a fifth aspect of the present invention is the image carrier according to any one of the first to fourth aspects, wherein the pressing portion has a contact portion in contact with an end surface of the substrate. And

  An image carrier according to a sixth aspect of the present invention is the image carrier according to the fifth aspect, wherein the image carrier is attached to an end portion of the base material, closes an opening of the base material, and supports the pressing portion. The contact part is provided, The said contact part is pinched | interposed by the end surface of the said base material, and the said closure part.

  An image carrier according to claim 7 of the present invention is the image carrier according to any one of claims 1 to 6, wherein the image carrier is a metal plate, and the pressing portion and the rotation shaft of the substrate are provided. A grounding plate having another pressing portion pressed against the outer peripheral surface of the shaft member is provided.

  An image forming unit according to an eighth aspect of the present invention includes the image carrier according to any one of the first to seventh aspects, and a charging member that charges an outer peripheral surface of the image carrier. And

  An image forming apparatus according to a ninth aspect of the present invention develops an electrostatic latent image formed by exposing the outer peripheral surface of the image forming unit according to the eighth aspect and the charged image carrier. And a transfer member that transfers the toner image formed in step 1 to a recording medium.

  According to a tenth aspect of the present invention, there is provided an image forming apparatus according to any one of the first to seventh aspects, a charging member that charges an outer peripheral surface of the image holding body, and the charged image holding apparatus. And a transfer member that transfers a toner image formed by developing an electrostatic latent image formed by exposing the outer peripheral surface of the body to a recording medium.

  According to the image carrier of claim 1 of the present invention, in the configuration in which the pressing portion is pressed against the inner peripheral surface of the base material having a thickness of 0.4 [mm], the outer periphery of the base material at the portion where the pressing portion is pressed The roundness of the surface can be 40 [μm] or less.

  According to the image holding body of the second aspect of the present invention, the connection between the base material and the pressing portion is prevented from being hindered by the adhesive as compared with the case where the pressing force is 0.3 [N]. be able to.

  According to the image carrier of claim 3 of the present invention, as compared with the case where the pressing portion is a protrusion protruding toward the inner peripheral surface side of the base material when viewed from the axial direction of the base material, Deformation can be suppressed.

  According to the image carrier of claim 4 of the present invention, the deformation of the base material is reduced as compared with the case where the radius of the pressing portion viewed from the axial direction of the base material is smaller than the radius of the inner peripheral surface of the base material. Can be suppressed.

  According to the image carrier of the fifth aspect of the present invention, the base material and the pressing portion are in contact with each other in the radial direction of the base material even when the base material and the pressing portion are separated from each other.

  According to the image carrier of claim 6 of the present invention, the contact portion is separated from the end surface of the substrate as compared with the case where a gap is formed in a portion of the contact portion opposite to the end surface of the substrate. Can be suppressed.

  According to the image carrier of claim 7 of the present invention, the base material and the shaft member can be connected via the ground plate.

  According to the image forming unit of the present invention, the roundness of the outer peripheral surface of the base material at the portion where the pressing portion is pressed is not provided with an image carrier having a circularity of 40 [μm] or less. Thus, density unevenness of the image on the image carrier can be suppressed.

  According to the image forming apparatus of the ninth aspect of the present invention, as compared with the case where no image carrier having a roundness of 40 [μm] or less of the outer peripheral surface of the base material at the portion where the pressing portion is pressed is provided. Thus, density unevenness in the output image can be suppressed.

  According to the image forming apparatus of the tenth aspect of the present invention, as compared with the case where no image carrier having a roundness of 40 [μm] or less of the outer peripheral surface of the base material at the portion where the pressing portion is pressed is provided. Thus, density unevenness in the output image can be suppressed.

It is an expanded sectional view showing the image carrier concerning a 1st embodiment of the present invention. It is sectional drawing which showed the image holding body which concerns on 1st Embodiment of this invention. It is an expanded sectional view showing the image carrier concerning a 1st embodiment of the present invention. It is the perspective view which showed the grounding member and closing member of the image holding body which concern on 1st Embodiment of this invention. 1 is an exploded perspective view showing an image carrier according to a first embodiment of the present invention. It is drawing which showed the evaluation result of Example 1, Example 2, the comparative example 1, and the comparative example 2 of 1st Embodiment of this invention with the table | surface. It is explanatory drawing used for demonstrating the method to measure the pressing force of the ear | edge part of the image holding body which concerns on 1st Embodiment of this invention. 1 is a side view illustrating an image carrier and a developing device according to a first embodiment of the present invention. 1 is a side view showing an image carrier and a charging member according to a first embodiment of the present invention. (A) (B) (C) It is process drawing which showed the manufacturing process of the base material which comprises the image holding body which concerns on 1st Embodiment of this invention. (A) (B) It is process drawing which showed the manufacturing process of the base material which comprises the image holding body which concerns on 1st Embodiment of this invention. It is the perspective view which showed the punch type | mold and ironing type | mold used for manufacturing the base material which comprises the image holding body which concerns on 1st Embodiment of this invention. (A) (B) (C) It is process drawing which showed the manufacturing process of the base material which comprises the image holding body which concerns on 1st Embodiment of this invention. (A) (B) (C) It is process drawing which showed the manufacturing process of the base material which comprises the image holding body which concerns on 1st Embodiment of this invention. (A) (B) (C) It is process drawing which showed the manufacturing process of the base material which comprises the image holding body which concerns on 1st Embodiment of this invention. 1 is a schematic configuration diagram illustrating an image forming apparatus according to a first embodiment of the present invention. It is the perspective view which showed the grounding member and closing member of the image holding body which concern on 2nd Embodiment of this invention. It is sectional drawing which showed the image holding body which concerns on 2nd Embodiment of this invention. It is the perspective view which showed the grounding member and closing member of the image holding body which concern on 3rd Embodiment of this invention. It is sectional drawing which showed the earthing | grounding member, closing member, etc. of the image carrier which concerns on 3rd Embodiment of this invention.

<First Embodiment>
An example of the image carrier, the image forming unit, and the image forming apparatus according to the first embodiment of the present invention will be described with reference to FIGS. In the drawing, an arrow H indicates the vertical direction of the apparatus (vertical direction), an arrow W indicates the apparatus width direction (horizontal direction), and an arrow D indicates the depth direction of the apparatus (horizontal direction).

(overall structure)
As illustrated in FIG. 16, the image forming apparatus 10 according to the present embodiment includes a storage unit 14 that stores a sheet member P serving as a recording medium, and a transport that transports the sheet member P stored in the storage unit 14. Part 16 is provided. Further, the image forming apparatus 10 includes an image forming unit 20 that forms an image on the sheet member P conveyed from the storage unit 14 by the conveying unit 16, and a control unit 48 that controls each unit.

[Container]
The accommodating portion 14 is provided with an accommodating member 14A that can be pulled out from the apparatus main body 10A of the image forming apparatus 10 toward the front side in the apparatus depth direction, and the sheet member P is stacked on the accommodating member 14A. Further, the accommodating portion 14 is provided with a delivery roll 14 </ b> B that sends out the sheet member P stacked on the accommodating member 14 </ b> A to the conveying path 28 constituting the conveying portion 16.

[Transport section]
The transport unit 16 includes a plurality of transport rolls (reference numerals omitted) that transport the sheet member P along the transport path 28 along which the sheet member P is transported.

(Image forming part)
The image forming unit 20 includes four image forming units 18Y, 18M, 18C, and 18K of yellow (Y), magenta (M), cyan (C), and black (K), and an exposure light to an image carrier 26 described later. And an exposure device 42 for irradiating. In the following description, Y, M, C, and K may be omitted when there is no need to distinguish between Y, M, C, and K.

  Each color image forming unit 18 (so-called process cartridge) is detachable from the apparatus main body 10A. Each color image forming unit 18 includes an image carrier 26 and a charging member 38 that charges the surface of the image carrier 26. Further, the image forming unit 18 is provided with a developing device 36 that develops the electrostatic latent image formed by irradiating the charged image carrier 26 with exposure light from the exposure device 42 and visualizes it as a toner image. Yes. Details of the charging member 38, the developing device 36, and the image carrier 26 will be described later.

  Further, the image forming unit 20 includes an endless transfer belt 22 that circulates in the direction of arrow A in the figure, and a primary transfer roll 44 that transfers the toner image formed by the image forming unit 18 of each color to the transfer belt 22. Is provided. Further, the image forming unit 20 heats and presses the secondary transfer roll 46 that transfers the toner image transferred to the transfer belt 22 to the sheet member P, and the sheet member P to which the toner image is transferred, and thereby the toner image. Is fixed to the sheet member P. The secondary transfer roll 46 is an example of a transfer member.

(Operation of image forming apparatus)
In the image forming apparatus 10, an image is formed as follows.

  First, each color charging member 38 uniformly negatively charges the surface of each color image carrier 26 with a predetermined potential. Subsequently, the exposure device 42 irradiates the surface of the charged image carrier 26 with exposure light to form an electrostatic latent image. Thereby, an electrostatic latent image is formed on the surface of the image carrier 26 of each color. Further, each color developing device 36 develops the electrostatic latent image and visualizes it as a toner image. In addition, the toner images formed on the surface of each color image carrier 26 are sequentially transferred to the transfer belt 22 by the primary transfer roll 44.

  Therefore, the sheet member P sent out from the accommodating member 14A to the transport path 28 by the sending roll 14B is sent out to the transfer position T where the transfer belt 22 and the secondary transfer roll 46 are in contact with each other. At the transfer position T, the sheet member P is conveyed between the transfer belt 22 and the secondary transfer roll 46, whereby the toner image on the transfer belt 22 is transferred to the sheet member P.

  Further, the toner image transferred to the sheet member P is fixed to the sheet member P by the fixing device 50. Then, the sheet member P on which the toner image is fixed is discharged to the outside of the apparatus main body 10A.

(Main part configuration)
Next, the configuration of the charging member 38, the developing device 36, the image carrier 26, and the method for manufacturing the base member 80 constituting the image carrier 26 will be described.

[Charging member 38]
The charging member 38 is disposed below the image carrier 26 as shown in FIG. The charging member 38 includes a shaft member 92 extending in the apparatus depth direction and a cylindrical elastic portion 94 through which the shaft member 92 passes. The shaft member 92 is rotatably supported by a support member 98 that forms a part of the casing of the image forming unit 18. Further, the outer peripheral surface of the elastic portion 94 is in contact with the image carrier 26. Then, a voltage is applied to the shaft member 92, and the charging member 38 rotates following the rotating image holding member 26, whereby the charging member 38 charges the surface of the image holding member 26.

[Developing device 36]
As shown in FIG. 8, the developing device 36 is arranged on one side (lower side in the drawing) in the apparatus width direction with respect to the image holding body 26, holds the developer, and is in contact with the image holding body 26. A developing roll 74 having a developing gap (gap) therebetween is provided. Further, the developing device 36 includes a shaft member 78 that constitutes a rotating shaft of the developing roll 74 and a pair of adjusting rolls 76.

  The shaft member 78 is rotatably supported by the support member 98. Further, the pair of adjustment rolls 76 are attached to the shaft member 78 so as to sandwich the developing roll 74 from the apparatus depth direction. The pair of adjustment rolls 76 have the same configuration, and the outer diameter of each adjustment roll 76 is larger than the outer diameter of the developing roll 74.

  In this configuration, the development gap (gap) is formed between the developing roll 74 and the image holding body 26 by the outer peripheral surfaces of the pair of adjusting rolls 76 being in contact with the image holding body 26.

[Image carrier 26]
As shown in FIGS. 2 and 5, the image holding body 26 includes a cylindrical base material 80 that has the depth direction of the apparatus as an axial direction and extends in the depth direction of the apparatus. Further, the image holding body 26 is fitted to the near end of the base material 80 in the apparatus depth direction to close the opening of the base material 80, and the base material 80 has the depth side in the apparatus depth direction. And a closing member 84 that closes the opening of the base material 80. The image carrier 26 is formed on a shaft member 54 that constitutes the rotation axis of the image carrier 26, a ground member 64 for grounding the image carrier 26, and an outer peripheral surface 80 </ b> B of the base material 80, so that light is transmitted. And a photosensitive layer 86 on which an electrostatic latent image is formed by changing properties when irradiated.

-Base material 80, photosensitive layer 86-
As an example, the base member 80 is formed in a cylindrical shape using aluminum, and has an outer diameter of 30 [mm], a length of 253 [mm], and a thickness of 0.4 [mm]. In addition, although it described as 0.4 [mm] about the thickness of the base material 80, when manufacturing dispersion | variation is considered, thickness is 0.35 [mm] or more and 0.45 [mm] or less. That is, the “thickness 0.4 [mm] of the substrate 80” is a thickness of 0.35 [mm] or more and 0.45 [mm] or less.

  Thus, since the thickness of the base material 80 is 0.4 [mm], for example, the mass is lighter than that of a conventional base material having a thickness of 0.7 [mm]. And the cost is reduced. In other words, the cost of the image carrier 26 is reduced as compared with the case where a base material having a thickness of 0.7 [mm] is used.

  The photosensitive layer 86 is formed by providing a photosensitive layer containing a charge generating material that generates charges when irradiated with light on the outer peripheral surface 80B (see FIG. 2).

  -Occlusion member 82, Occlusion member 84-

  The closing member 82 is formed by using a polycarbonate resin as an example. As shown in FIGS. 2 and 8, a part of the closing member 82 is inserted into the inside of the substrate 80. 80 is fitted to the end. In this state, the closing member 82 closes the opening of the base material 80.

  The closing member 82 includes a contact surface 82B in which the end surface of the base material 80 is abutted in the axial direction of the base material 80 in a state where the closing member 82 is fitted to the end portion of the base material 80, and a contact surface 82B. One end is in contact with the inner peripheral surface 80 </ b> A of the base material 80 and a facing surface 82 </ b> C facing the inner peripheral surface 80 </ b> A. Further, the closing member 82 has a conical surface 82D, one end of which is in contact with the opposing surface 82C, and the outer diameter gradually decreases, and a through hole 82A through which the shaft member 54 passes.

  The diameter of the through hole 82A is, for example, 5 [mm]. Then, the closing member 82 rotates integrally with the shaft member 54 by passing a shaft member 54 described later through the through hole 82A. Further, the portion of the base material 80 that faces the facing surface 82C and the inner peripheral surface 80A of the base material 80 are bonded by an adhesive S (for example, a cyanoacrylate adhesive). Specifically, a part of the blocking member 82 is inserted into the base member 80 in a state where the adhesive S is applied to the end portion side portion of the inner peripheral surface 80 </ b> A of the base member 80. The opposing surface 82 </ b> C of 82 and the inner peripheral surface 80 </ b> A of the base material 80 are bonded together with an adhesive S. Here, the adhesive S is applied to the inner peripheral surface 80 </ b> A of the base member 80 in a range longer than the length of the facing surface 82 </ b> C of the closing member 82 from the end portion of the inner peripheral surface 80 </ b> A of the base member 80.

  For example, the closing member 84 is formed using a polycarbonate resin. As shown in FIGS. 1 and 2, a part of the closing member 84 is inserted into the inside of the base member 80. 80 is fitted to the end. In this state, the closing member 84 closes the opening of the base material 80. The closing member 84 is an example of a closing part.

  The closing member 84 includes a contact surface 84B on which the end surface of the base material 80 is abutted in the axial direction of the base material 80 in a state where the closing member 82 is fitted to the end portion of the base material 80, and a contact surface 84B. One end is in contact with the inner peripheral surface 80 </ b> A of the base material 80 and an opposing surface 84 </ b> C that faces the inner peripheral surface 80 </ b> A. Further, the closing member 84 has one end in contact with the opposing surface 84C, and is surrounded by a conical surface 84D having a gradually decreasing outer diameter, and an end edge of the conical surface 84D, and has a circular shape facing the closing member 82 side. It has a circular surface 84E and a through hole 84A through which the shaft member 54 passes.

  The diameter of the through hole 84A is set to 5 [mm] as an example. Then, the closing member 84 rotates integrally with the shaft member 54 by passing a shaft member 54 described later through the through hole 84A.

  Further, the portion of the base material 80 that faces the facing surface 84C and the inner peripheral surface 80A of the base material 80 are bonded by an adhesive S (for example, a cyanoacrylate adhesive). Specifically, a part of the blocking member 84 is inserted into the base member 80 in a state where the adhesive S is applied to the end portion side portion of the inner peripheral surface 80 </ b> A of the base member 80. The facing surface 84 </ b> C of 84 and the inner peripheral surface 80 </ b> A of the base material 80 are bonded together with an adhesive S. Here, the adhesive S is applied to the inner peripheral surface 80 </ b> A of the base member 80 in a range longer than the length of the facing surface 84 </ b> C of the closing member 84 from the end portion of the inner peripheral surface 80 </ b> A of the base member 80.

−Shaft member 54−
As an example, the shaft member 54 uses a conductive SUM-Ni shaft (a shaft obtained by applying nickel plating to sulfur free-cutting steel) and has an outer diameter of 5 [mm] and a total length of 355 [mm]. . Then, both end portions of the shaft member 54 are rotatably supported by the support member 98 as shown in FIG. The shaft member 54 is electrically connected to a metal frame (not shown) and is grounded.

  Further, a gear 90 constituting the image forming unit 18 is attached to one end portion of the shaft member 54, and the rotational force from the motor 88 provided in the image forming apparatus 10 is transmitted through the gear 90 to the image. It is transmitted to the holding body 26.

-Grounding member 64-
As shown in FIGS. 1 and 4, the grounding member 64 is disposed inside the base material 80 on the closing member 82 side of the closing member 84. The grounding member 64 includes a metal plate-shaped grounding plate 66 and a pair of conductive members 68 made of resin and having a rectangular parallelepiped shape.

  As an example, the ground plate 66 is formed by trimming a SUS304-CSP tempered symbol H (JIS G 4313: 1996) having a thickness of 0.2 [mm] into a predetermined shape and bending it. It has a circular main body portion 66A, a pair of ear portions 66B, and a pair of cut-and-raised portions 66C. The ear part 66B is an example of a pressing part.

  The outer diameter of the main body portion 66A is the same as the outer diameter of the circular surface 84E of the closing member 84, and the main body portion 66A is overlapped with the circular surface 84E of the closing member 84. Then, the grounding member 64 is attached to the closing member 84 by fixing a fixing portion (not shown) of the main body portion 66A to a fixing portion (not shown) of the circular surface 84E. Specifically, the main body portion 66A is fixed to the circular surface 84E so that the main body portion 66A does not float from the circular surface 84E.

  A pair of ear portions 66B are provided across the center of the circular main body portion 66A, and each ear portion 66B closes a portion protruding in the radial direction of the main body portion 66A from the outer peripheral edge of the main body portion 66A. It is formed by bending toward the member 84 side. Thereby, the ear | edge part 66B is a cantilever part in the state by which the base end was bent. And the front-end | tip (free end) of this ear | edge part 66B is pressed on the internal peripheral surface 80A of the base material 80 (refer FIG. 2). That is, the ear portion 66B is a leaf spring whose base end is elastically deformed. In the present embodiment, the position where the tip of the ear 66B is pressed against the inner peripheral surface 80A of the base member 80 is a position away from the end of the base member 80 by about 3.5 mm. Further, the position where the tip of the ear 66B is pressed against the inner peripheral surface 80A of the base member 80 is a position away from the image forming area where the toner image is formed on the image carrier 26 by about 18 mm.

  The ear 66B has a rectangular shape in which R is formed (rounded) at the corner of the free end. The width of the ear portion 66B (L2 in the figure) is 3 [mm], and the length of the ear portion 66B (L3 in the figure) is 3.5 [mm].

  Here, the tips of the respective ear portions 66B are pressed against the inner peripheral surface 80A of the base member 80 with a pressing force of 0.5 [N] or more and 5.0 [N] or less. In addition, about the pressing force mentioned above, 1.0 [N] or more and 4.0 [N] or less are preferable, and 2.0 [N] or more and 3.0 [N] or less are more preferable. As for the measurement of the pressing force, as shown in FIG. 7, the closing member 84 is attached to the jig G with a fixture (not shown) while the grounding member 64 is attached to the closing member 84.

  Then, using a push-pull gauge, force is detected while pressing the ear 66B against the center line C1 side (arrow F side in the figure) of the closing member 84 in increments of 0.1 [mm]. Further, a graph of the pressing amount and the detected force is prepared, and the force detected at a position corresponding to the inner peripheral surface 80A of the base member 80 is pressed against the inner peripheral surface 80A of the base member 80 by the ear portion 66B. The pressing force to be used. That is, the tip of the ear portion 66B in a free state (a state where no external force is applied) is on the outer side in the radial direction of the base material 80 (on the opposite side to the center) as compared with the inner peripheral surface 80A of the base material 80. positioned. In addition, the pressing force of the ear | edge part 66B is a pressing force of the one ear | edge part 66B.

  As shown in FIGS. 3 and 4, a pair of cut and raised portions 66 </ b> C is provided across the center of the circular main body portion 66 </ b> A. Each cut-and-raised portion 66C is formed by cutting and raising a portion, which is surrounded by the outer peripheral edge of the main body portion 66A and arranged in the same planar shape as the main body portion 66A, on the side opposite to the closing member 84. Has been. That is, the cut and raised portion 66C is a leaf spring.

  Specifically, the cut and raised portion 66C is in a cantilever state by cutting and raising the center side of the circular main body portion 66A. Further, when viewed from the apparatus depth direction (the thickness direction of the main body portion 66A), the facing direction of the pair of cut and raised portions 66C intersects the facing direction of the pair of ear portions 66B.

  The conductive member 68 is formed in a rectangular parallelepiped shape using a resin material having conductivity. A pair of the conductive members 68 are provided, and the pair of conductive members 68 are attached to the surfaces of the pair of cut-and-raised portions 66C facing each other using a fixture (not shown). In this state, conduction between the conductive member 68 and the cut-and-raised portion 66C is ensured. As shown in FIG. 3, the pair of conductive members 68 are pressed against the outer peripheral surface 54A of the shaft member 54 by the cut and raised portions 66C.

  In this way, the lug 66B of the grounding member 64 is pressed against the inner peripheral surface 80A of the base member 80, and the conductive member 68 of the grounding member 64 is pressed against the outer peripheral surface 54A of the shaft member 54. The holding body 26) is grounded.

The “conductive resin material” is a resin material having a volume resistivity of 10 ¹⁰ [Ω · cm] or less. In this embodiment, polyacetal resin conductive grade (POM EW-02) is used as an example of “conductive resin material”.

[Method for Producing Substrate 80]
Next, the manufacturing method of the base material 80 is demonstrated. The base material 80 is manufactured including impact processing for forming the cylindrical cylindrical material 206 and ironing processing for correcting the cylindrical material 206 to form the base material 80.

-Impact processing-
In the impact processing, a cylindrical material 206 having a bottom and a cylindrical shape is formed from the slag 202 which is a lump of aluminum. In the impact processing, as shown in FIG. 10A, the concave mold 204 in which the slag 202 which is a lump of aluminum is stored, and the slag 202 stored in the concave mold 204 are pressed to make the slag 202 cylindrical. A cylindrical punch mold 200 is used. The concave portion 204A of the concave mold 204 is circular, and the inner diameter of the concave portion 204A is, for example, 32.0 [mm]. The outer diameter of the punch die 200 is, for example, 30.6 [mm].

  In the impact process, first, the slag 202 is accommodated in the concave mold 204, and the punch mold 200 is further disposed above the concave mold 204 (see FIG. 10A).

  Next, as shown in FIGS. 10B and 10C, the punch die 200 moves downward and crushes and deforms the slag 202 accommodated in the concave die 204. As a result, the slag 202 is deformed into a cylindrical material 206 having a bottom and a cylindrical shape along the peripheral surface of the punch die 200. As an example, the thickness of the cylindrical material 206 is 0.7 [mm] and the inner diameter is 30.6 [mm].

  Next, the punch die 200 moves upward, and the cylindrical material 106 that is in close contact with the punch die 200 is separated from the concave die 104 as shown in FIG. Further, as shown in FIG. 11B, the cylindrical member 106 is pulled out (demolded) from the punch die 200.

-Ironing process-
The ironing process reduces the thickness of the cylindrical material 206 and corrects the shape of the cylindrical material 206. In the ironing process, as shown in FIG. 12, a punch mold 220 inserted from the tip (lower end in the figure) into the cylindrical material 206 (see FIG. 11B), and an inner peripheral surface 206A of the cylindrical material 206 (see FIG. 12). 11 (B)) is used as the ironing die 222 that follows the outer peripheral surface 220A of the punch die 220.

  The punch die 220 has a cylindrical shape extending in the vertical direction (one direction). As an example, the outer diameter of the punch die 220 is 29.2 [mm]. Further, the ironing die 222 has an annular shape, and, as an example, the inner diameter is 30.0 [mm].

  In the ironing process, first, as shown in FIG. 13A, the punch die 220 is inserted into the cylindrical member 206 from the tip. 13A, 13B, 14C, and 14B, illustration of the gap between the outer peripheral surface of the punch die 220 and the inner peripheral surface 206A of the cylindrical material 206 is omitted.

  Next, FIGS. 13B, 14C, 14A, 14B, and 14C show the cylindrical material 206 into which the punch die 220 is inserted from the position where the cylindrical material 206 is moved above the ironing die 222. In this way, it moves downward and passes through the inside of the ironing die 222. As a result, the ironing die 222 presses the cylindrical material 206 against the punch die 220, thereby reducing the thickness of the cylindrical material 206. Further, the inner peripheral surface 206 A of the cylindrical material 206 follows the outer peripheral surface 220 A of the punch die 220. .

  Next, as shown in FIGS. 15A and 15B, the cylindrical material 206 is pulled out (demolded) from the punch mold 220. Further, the lower end of the cylindrical material 206 is cut off, and as shown in FIG. 15C, a cylindrical base material 80 having both ends opened is formed.

(Effects of main components)
Next, the operation of the main configuration will be described.

  A motor 88 shown in FIG. 9 rotates the image carrier 26. As the image carrier 26 rotates, the charging member 38 rotates following the image carrier 26. Further, a voltage is applied to the shaft member 54 of the charging member 38 from a power source (not shown).

  As shown in FIG. 2, the image carrier 26 is grounded by electrically connecting the base member 80 constituting the image carrier 26 to the shaft member 54 via the ground member 64. For this reason, a current flows between the charging member 38 and the image carrier 26, and the surface of the image carrier 26 is uniformly charged. Then, an electrostatic latent image is formed on the surface of the charged image carrier 26 by irradiation of exposure light from the exposure device 42 (see FIG. 16).

  Further, the electrostatic latent image formed on the image carrier 26 is visualized as a toner image by the developing device 36 shown in FIG. Specifically, the outer peripheral surfaces of the pair of adjusting rolls 76 of the developing device 36 are in contact with the image holding body 26, so that a developing gap (gap) is formed between the developing roll 74 of the developing device 36 and the image holding body 26. It is formed. Then, toner is transferred from the development gap to the electrostatic latent image, and the electrostatic latent image is visualized as a toner image.

(Evaluation)
Next, evaluation performed on the image carrier 26 according to the example of the first embodiment and the image carrier according to the comparative example will be described.

  [Each configuration]

  First, the configurations of Examples 1 and 2 and Comparative Examples 1 and 2 will be described using the table shown in FIG. In addition, about the matter which is not described below, it is the same structure altogether between each member.

Example 1 For the image carrier 26 of Example 1, a base material 80 having a thickness of 0.35 [mm] was used.

That is, when the base material 80 having a thickness of 0.4 [mm] is used, the base material 80 having a thickness of 0.35 [mm] that is the thinnest in consideration of manufacturing variation is used. Further, the grounding member 64 is used in which the pressing force of the ear portion 66B against the inner peripheral surface 80A of the substrate 80 is 5.0 [N].

Example 2⇒A substrate 80 having a thickness of 0.35 [mm] was used for the image carrier 26 of Example 2. Further, the grounding member 64 is used in which the pressing force of the ear portion 66B against the inner peripheral surface 80A of the substrate 80 is 0.5 [N].

Comparative Example 1 A substrate 80 having a thickness of 0.35 [mm] was used for the image carrier 26 of Comparative Example 1. Further, a grounding member is used in which the pressing force of the ear portion 66B against the inner peripheral surface 80A of the base material 80 is 6.0 [N].

Comparative Example 2⇒ For the image carrier 26 of Comparative Example 2, a base material 80 having a thickness of 0.35 [mm] was used. Further, a grounding member is used in which the pressing force of the ear portion 66B against the inner peripheral surface 80A of the base material 80 is 0.3 [N].

〔Evaluation item〕
Base material deformation evaluation: Roundness of the outer peripheral surface of the base material at the portion where the tip (free end) of the ear portion 66B is pressed against the image carriers of Examples 1 and 2 and Comparative Examples 1 and 2 (JIS B 0419) was measured. In addition, the roundness of the base material before attaching the closing member 84 was 11 [μm] or more and 14 [μm] or less. When the roundness was 40 [μm] or less, the substrate deformation evaluation was “◯”. In addition, when the roundness was larger than 40 [μm], the base material deformation evaluation was “x”.

  In consideration of the past results, when the roundness is 40 [μm] or less at the site measured this time, the density unevenness of the output image caused by the roundness of the image forming area of the substrate 80 is This is an acceptable level in terms of merchantability.

  The roundness was measured using a roundness measuring device Rondcom (manufactured by Tokyo Seimitsu Co., Ltd.).

  Ground resistance evaluation: A voltage of 10 [V] was applied between the substrate 80 and the shaft member 54 to measure a resistance value [Ω]. When the resistance value was 100 [Ω] or less, the ground resistance evaluation was “◯”. In addition, when the resistance value is larger than 100 [Ω], the ground resistance evaluation is “x”.

  Considering the past results, when the resistance value is 100 [Ω] or less, the density unevenness of the output image caused by the charging unevenness is an acceptable level in terms of merchantability.

〔Evaluation results〕
For the base material deformation evaluation, the roundness is 35 [μm] in the case of Example 1, the roundness is 24 [μm] in the case of Example 2, and the roundness is 20 [μm] in the case of Comparative Example 2. And it was “○”. On the other hand, in the case of the comparative example 1, the roundness was 46 [μm] and “x”. This is because the pressing force of the ear portion 66B against the inner peripheral surface 80A of the base material 80 is larger than 5.0 [N], so that the base material 80 is deformed.

  Regarding the ground resistance evaluation, in the case of Example 1, it was 70 [Ω], in the case of Example 2 it was 90 [Ω], and in the case of Comparative Example 1 it was 60 [Ω], which was “◯”. On the other hand, in the case of Comparative Example 2, it was 115 [Ω] and “x”. This is because the pressing force of the ear portion 66B against the inner peripheral surface 80A of the substrate 80 is smaller than 0.5 [N]. For this reason, the adhesive applied to the inner peripheral surface 80A of the base member 80 in order to attach the closing member 84 to the base member 80 remains between the tip of the ear portion 66B and the inner peripheral surface 80A of the base member 80, It is thought that the flow of electricity was hindered by this adhesive.

(Summary)
As can be seen from the above evaluation results, in this embodiment, the pressing force of the ear 66B against the inner peripheral surface 80A of the base member 80 is 5.0 [N] or less. For this reason, in the structure which presses an ear | edge part to the internal peripheral surface of a 0.4 [mm] thickness base material, a deformation | transformation of the base material 80 is suppressed compared with the case where pressing force is 6.0 [N]. The

  Moreover, in this embodiment, the pressing force of the ear | edge part 66B with respect to the internal peripheral surface 80A of the base material 80 is 0.5 [N] or more. For this reason, compared with the case where pressing force is 0.3 [N], the electrical connection of the base material 80 and the ear | edge part 66B is obstructed by the adhesive applied to the inner peripheral surface 80A of the base material 80. It is suppressed that it is done.

  Further, since the deformation of the base material 80 is suppressed, in the image forming unit 18, the image carrier 26 generated due to the deformation of the base material 80 is compared with the case where the pressing force is 6.0 [N]. Density unevenness of the upper toner image is suppressed.

  Further, since the electric flow between the base member 80 and the shaft member 54 is suppressed from being inhibited, in the image forming unit 18, compared with the case where the pressing force is 0.3 [N], Density unevenness of the toner image on the image carrier 26 caused by the charging failure of the image carrier 26 is suppressed.

  Further, in the image forming apparatus 10, by providing the image holding body 26, the density unevenness of the output image is suppressed as compared with the case where the pressing force of the ear 66 B is 6.0 [N].

Second Embodiment
An example of the image carrier, the image forming unit, and the image forming apparatus according to the second embodiment of the present invention will be described with reference to FIGS. In addition, about 2nd Embodiment, a different part from 1st Embodiment is mainly demonstrated.

  The pressing portion 368 pressed against the inner peripheral surface of the base member 80 in the ear portion 366B of the grounding member 364 of the second embodiment (in this embodiment, the free end of the ear portion 366B) protrudes toward the base member 80 side. (See FIG. 17). Specifically, as shown in FIG. 18, the radius of the pressing portion 368 is the same as the radius of the inner peripheral surface 80 </ b> A of the substrate 80 when viewed from the apparatus depth direction (the axial direction of the substrate 80). In other words, the pressing portion 368 is along the inner peripheral surface 80 </ b> A of the base material 80 when viewed from the apparatus depth direction. The ear part 366B is an example of a pressing part.

  Here, “the radius of the pressing portion 368 is the same as the radius of the inner peripheral surface 80 </ b> A of the base material 80” means that the pressing portion 368 has a height of 80 when viewed from the central axis direction (device depth direction) of the base material 80. [%] The above is in contact with the inner peripheral surface 80A of the substrate 80. Note that the situation of contact can be determined by irradiating light from the opposite side being viewed and confirming light leakage.

  Thus, the pressing portion 368 has a curved shape protruding toward the base material 80 side. For this reason, it is suppressed that a base material deform | transforms compared with the case where a pressing part is made into linear form.

  Further, when viewed from the depth direction of the apparatus, the radius of the pressing portion 368 is the same as the radius of the inner peripheral surface 80 </ b> A of the base material 80. For this reason, it is suppressed that a base material deform | transforms compared with the case where the radius of the pressing part 368 is smaller than the radius of the internal peripheral surface 80A of the base material 80. FIG.

  In addition, about another effect | action of 2nd Embodiment, it is the same as that of 1st Embodiment.

<Third Embodiment>
An example of an image carrier, an image forming unit, and an image forming apparatus according to a third embodiment of the present invention will be described with reference to FIGS. In addition, about 3rd Embodiment, a different part from 1st Embodiment is mainly demonstrated.

  The ear portion 466B of the ground contact member 464 of the third embodiment includes a pressing portion 468 that is pressed against the inner peripheral surface 80A of the base member 80, a contact portion 470 that contacts the end surface 80C (see FIG. 20) of the base member 80, A connecting portion 472 that connects the pressing portion 468 and the contact portion 470 is provided.

  The connecting portion 472 extends from the pressing portion 468 to the depth side in the apparatus depth direction (on the side opposite to the main body portion 66 </ b> A) through a step, and is separated from the inner peripheral surface 80 </ b> A of the base material 80. The contact portion 470 extends from the end portion of the connecting portion 472 in the apparatus depth direction to the outer side in the radial direction of the main body portion 66A (side away from the shaft member 54). The ear portion 466B is an example of a pressing portion.

  Further, the closing member 484 of the third embodiment is formed with a counterbore part 484A in which the connection part 472 and the contact part 470 of the ear part 466B are accommodated. The counterbore part 484A is formed by making a part of the contact surface 84B, the opposing surface 84C, and the conical surface 84D of the closing member 484 concave.

  In this configuration, as shown in FIG. 20, the pressing portion 468 of the ear portion 466 </ b> B is pressed against the inner peripheral surface 80 </ b> A of the base material 80. In other words, the pressing portion 468 of the ear portion 466 </ b> B is pressed against the inner peripheral surface 80 </ b> A of the base material 80 in the radial direction of the base material 80.

  Furthermore, the contact portion 470 of the ear portion 466B is sandwiched between the end surface 80C of the base material 80 and the closing member 484 in the apparatus depth direction (the axial direction of the base material 80). The contact portion 470 is in contact with the end face 80 </ b> C of the base material 80. In other words, the contact portion 470 of the ear portion 466 </ b> B is in contact with the end surface 80 </ b> C of the base material 80 in the axial direction of the base material 80.

  In this way, the contact portion 470 of the ear portion 466B is in contact with the end face 80C of the base member 80 in the axial direction of the base member 80. Therefore, for example, even when the image carrier 26 vibrates and the inner peripheral surface 80A of the base member 80 and the pressing portion 468 are separated in the radial direction of the base member 80, the base member 80 and the ear portion 466B are separated from each other. Electrically connected.

  Further, the contact portion 470 of the ear portion 466 </ b> B is sandwiched between the end surface 80 </ b> C of the base material 80 and the closing member 484. For this reason, it is suppressed that the contact part 470 separates from the end surface 80C of the base material 80 compared with the case where the space | gap is formed in the part on the opposite side to the base material 80 in the contact part 470.

  Moreover, since the contact part 470 is formed in the ear | edge part 466B, the yield at the time of shape | molding the grounding board 66 improves compared with the case where the contact part is formed in the site | part different from the ear | edge part 466B. Further, other operations of the third embodiment are the same as the operations of the first embodiment.

  Although the present invention has been described in detail with respect to specific embodiments, the present invention is not limited to such embodiments, and various other embodiments can be taken within the scope of the present invention. This will be apparent to those skilled in the art. For example, in the above-described embodiment, two ear portions 66B, 366B, and 466B are formed on the grounding members 64, 364, and 464, but may be one or three or more. In the case of a plurality, by arranging at the same interval (pitch) in the circumferential direction of the base material 80, a decrease in roundness is suppressed.

  Moreover, in the said embodiment, although the ear | edge parts 66B, 366B, and 466B were pressed against the internal peripheral surface 80A of the base material 80 with the pressing force of 0.5 [N] or more, the pressing force is 0.5 [N]. It may be less. In this case, the effect exerted when the pressing force is 0.5 [N] or more is not achieved.

DESCRIPTION OF SYMBOLS 10 Image forming apparatus 18 Image forming unit 26 Image holding body 36 Developing apparatus 38 Charging member 46 Secondary transfer roll (an example of transfer member)
66B Ear part (an example of a pressing part)
80 Base material 80A Inner peripheral surface 80C End surface 84 Closure member 86 Photosensitive layer 366B Ear part (an example of pressing part)
368 Pressing portion 466B Ear portion (an example of pressing portion)
468 Pressing part 470 Contact part 484 Closing member

Claims (10)

A base made of aluminum and having a thickness of 0.4 mm;
A pressing portion pressed against the inner peripheral surface of the base material with a pressing force of 5.0 [N] or less;
A photosensitive layer formed on the outer peripheral surface of the substrate;
An image carrier comprising: Attached to the end of the base material, and closes the opening of the base material, and includes a closing portion that supports the pressing portion,
In the inner peripheral surface of the base material, an adhesive that adheres the blocking portion to the base material is applied to a portion where the pressing portion is pressed,
The image holding body according to claim 1, wherein the pressing portion is pressed against the inner peripheral surface of the base material with a pressing force of 0.5 [N] or more.   The pressing portion that is pressed against the inner peripheral surface of the base material in the pressing portion when viewed from the axial direction of the base material has a curved shape that protrudes toward the base material side. Image carrier.   The image carrier according to claim 3, wherein the radius of the pressing portion is the same as the radius of the inner peripheral surface of the base material when viewed from the axial direction of the base material.   The image holding body according to any one of claims 1 to 4, wherein the pressing portion includes a contact portion in contact with an end surface of the base material. Attached to the end of the base material, and closes the opening of the base material, and includes a closing portion that supports the pressing portion,
The image holding body according to claim 5, wherein the contact portion is sandwiched between an end surface of the base material and the blocking portion.   7. The ground plate according to claim 1, further comprising a ground plate having a metal plate shape and having the pressing portion and another pressing portion pressed against an outer peripheral surface of a shaft member that constitutes the rotation shaft of the base material. 2. An image carrier according to item 1. The image carrier according to any one of claims 1 to 7,
A charging member for charging the outer peripheral surface of the image carrier;
An image forming unit comprising: An image forming unit according to claim 8,
A transfer member for transferring a toner image formed by developing an electrostatic latent image formed by exposing the outer peripheral surface of the charged image carrier to a recording medium;
An image forming apparatus comprising: The image carrier according to any one of claims 1 to 7,
A charging member for charging the outer peripheral surface of the image carrier;
A transfer member for transferring a toner image formed by developing an electrostatic latent image formed by exposing the outer peripheral surface of the charged image carrier to a recording medium;
An image forming apparatus comprising: