JP7443695B2 - Charging device and image forming device - Google Patents

Description

The present invention relates to a charging device and an image forming apparatus equipped with the same.

2. Description of the Related Art Image forming apparatuses using electrophotography, such as copying machines and laser printers, are equipped with a charging device that uniformly charges the surface of an image carrier, which is a charged body. An electrostatic latent image is formed on the image carrier by removing a charged layer formed on the image carrier by the charging device with a laser beam based on an image signal. Next, a toner image is formed by depositing toner on the image bearing member on which the electrostatic latent image has been formed, and the toner image is transferred onto a recording medium such as paper directly or via a transfer belt.

As a charging device for charging an image carrier, there is a scorotron type charging device that uses corona discharge (for example, see Patent Document 1).
A scorotron-type charging device includes, for example, a wire as a discharge electrode arranged inside a frame, and a grid located between the wire and an image carrier. When a high voltage is applied to the wire, it generates a corona discharge and releases electric charge. The amount of charge introduced to the surface of the image carrier is controlled by the voltage applied to the grid.

Japanese Patent Application Publication No. 2002-365881

When a charging device is used for a long period of time, the wires and grids become contaminated with foreign matter. Therefore, in order to extend the product life, it is necessary to perform maintenance such as removing and replacing wires and grids from the charging device.

In the charging device of Patent Document 1, a locking portion to which one end of the grid is locked and a positioning portion to which one end of the wire is positioned are arranged side by side in the longitudinal direction of the charging device at one end of the charging device. ing. Here, the grid and the wire can be removed from the charging device in this order and replaced.
However, in this configuration, it is necessary to provide a sufficient distance between the locking part of the grid and the wire in order to ensure insulation, so the charging device is installed in the longitudinal direction of the grid or along the surface of the object to be charged. It becomes larger in the direction perpendicular to .

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a charging device that can suppress increase in size while ensuring maintainability, and an image forming apparatus equipped with the charging device.

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

(1) A charging device that charges an object to be charged, including blocks having insulating properties provided at both ends of the charging device in the longitudinal direction, a wire that generates discharge, the wire and the object to be charged. and a tensioning member having a one-side locking part that locks one end of the grid, the tensioning member being arranged between the wires in the block on one side. The tension member is attached to a portion closer to the object to be charged, and a boss portion is erected on the bottom wall of one of the blocks on the side of the object to be charged, and the tension member The tension member is attached to the end surface of the charged object side, and the tension member is attached to the end surface of the boss portion by a screw member that engages with a female thread formed on the end surface of the boss portion, and the tension member is attached to the end surface of the boss portion. The member is a stepped screw having a step between a head and a shaft in which a male thread is formed, and the step has a smaller diameter than the head and a larger diameter than the shaft; A charging device having a locking surface that locks onto the outer peripheral surface of the charging device.

(2) A charging device that charges an object to be charged, including blocks having insulating properties provided at both ends of the charging device in the longitudinal direction, a wire that generates discharge, the wire and the object to be charged. and a tensioning member having a one-side locking part that locks one end of the grid, the tensioning member being arranged between the wires in the block on one side. The tension member is attached to a portion closer to the object to be charged, and a boss portion is erected on the bottom wall of one of the blocks on the side of the object to be charged, and the tension member The tension member is attached to the end surface of the charged object side, and the tension member is attached to the end surface of the boss portion by a screw member that engages with a female thread formed on the end surface of the boss portion, and the tension member is attached to the end surface of the boss portion. The member is a stepped screw having a step between a head and a shaft in which a male thread is formed, and the step has a smaller diameter than the head and a larger diameter than the shaft; A charging device having a locking surface that locks onto the outer peripheral surface of the charging device.

(3) A charging device that charges an object to be charged, including a block having an insulating property provided at both longitudinal ends of the charging device, a wire that generates discharge, the wire and the object to be charged. and a tensioning member having a one-side locking part that locks one end of the grid, the tensioning member being arranged between the wires in the block on one side. The tension member is attached to a portion closer to the object to be charged, and a boss portion is erected on the bottom wall of one of the blocks on the side of the object to be charged, and the tension member It is attached to the end face on the side of the charged object , two grids are provided, and two one-side locking portions are provided on the tension member corresponding to each of the two grids. charging device.

(4) The tension member is described in any one of (1) to (3) above, wherein an outline of the tension member is arranged inside an outline of the block on one side when viewed from the side of the charged object. charging device.

(5) The block has a bottomed box shape with an opening on the side of the charged object, and a wire attachment part to which the wire is attached is provided in the block. The charging device described in .

(6) The charging device includes a frame extending in the longitudinal direction, and the block is attached by being press-fitted into a longitudinal opening formed at a longitudinal end of the frame . The charging device according to any one of (3) .

(7) The other side locking part that locks the other end of the grid is provided on the other end of the frame to which the block is attached. Charging device.

(8) The charging device according to (7), wherein one side of the grid is locked to the one side locking part via a spring member, and the other side of the grid is locked to the other side locking part. .

(9) The charging device according to any one of (1) to (8) , wherein the tension member is made of metal.

(10) A charging device that charges an object to be charged, including blocks having insulating properties provided at both longitudinal ends of the charging device, a wire that generates discharge, the wire and the object to be charged. and a tensioning member having a one-side locking part that locks one end of the grid, the tensioning member being arranged between the wires in the block on one side. Two grids are provided, and two one-side locking portions are attached to the tension member, corresponding to each of the two grids. Charging device provided.

(11) An image forming apparatus including the charging device according to any one of (1) to (10) above.

According to the present invention, it is possible to provide a charging device that can suppress increase in size while ensuring maintainability, and an image forming apparatus equipped with the charging device.

1 is a schematic configuration diagram of an image forming apparatus according to an embodiment of the present invention. FIG. 2 is a schematic enlarged configuration diagram showing one image forming unit of the image forming section. FIG. 3 is a perspective view of a frame of the charging device. FIG. 2 is a perspective view of a charging device. FIG. 3 is a plan view of the charging device. It is an exploded perspective view showing a block, a screw member, a lid, and a tension member. FIG. 3 is a plan view showing a state in which wires are attached between blocks provided at both ends in the longitudinal direction of the frame. 8 is a sectional view taken along line VIII-VIII in FIG. 7. FIG. It is a top view which shows the state which attached the cover and the tension member to the block to which the wire was attached. 6 is a sectional view taken along line XX in FIG. 5. FIG.

Embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
In each figure, common or similar components are designated by the same reference numerals, and their overlapping explanations will be omitted as appropriate.

FIG. 1 is a schematic configuration diagram of an image forming apparatus 100 including a charging device 20 according to an embodiment of the present invention.
As shown in FIG. 1, in this embodiment, the image forming apparatus 100 is a full-color tandem image forming apparatus. Note that the image forming apparatus 100 is not limited to this, and may be, for example, a simple drum-type image forming apparatus that supports black and white.

The image forming apparatus 100 includes an image forming section 1, a secondary transfer belt 2, a paper cassette 3, a secondary transfer section 4, a fixing roller 5, and the like. Image forming section 1 forms a toner image on secondary transfer belt 2 . Paper cassette 3 stores paper P. The secondary transfer unit 4 transfers the toner image from the secondary transfer belt 2 to the paper P that has been taken out from the paper cassette 3 and is being conveyed. The fixing roller 5 thermally fixes the toner image onto the paper P. The paper P on which the image has been formed is discharged onto a paper discharge tray 7 by a paper discharge roller 6.

The secondary transfer belt 2 is wound around a driving roller 8, a driven roller 9, and a tension roller 10. In the secondary transfer section 4, the toner image on the secondary transfer belt 2 is transferred onto the sheet P by pressing the sheet P toward the drive roller 8 with the secondary transfer roller 11. An image forming section 1 is arranged on the lower surface of the secondary transfer belt 2 . The image forming section 1 includes a yellow image forming unit 1Y, a magenta image forming unit 1M, a cyan image forming unit 1C, and a black image forming unit 1K, which are arranged in order in the feeding direction of the secondary transfer belt 2.

Each image forming unit 1Y, 1M, 1C, 1K has a drum-shaped photoreceptor 13 that contacts the outer peripheral surface of the secondary transfer belt 2 from below. A charging device 20 , a developing device 15 , and a cleaning unit 16 are arranged around the photoreceptor 13 . The charging device 20 charges the outer peripheral surface of the photoreceptor 13. The developing device 15 transfers developer to the outer peripheral surface of the photoreceptor 13 . The cleaning unit 16 removes developer remaining on the photoreceptor 13 without being transferred to the secondary transfer belt 2 . The secondary transfer belt 2 is maintained in contact with the photoreceptor 13 by a pressing roller 17 . The photoreceptor 13 is an example of an image carrier that is a charged body.

An exposure unit 18 is arranged below the image forming section 1 . An electrostatic latent image is formed on the outer peripheral surface of the photoreceptor 13 by irradiating the outer peripheral surface of the charged photoreceptor 13 with light L such as a laser beam from the exposure unit 18 . By transferring developer from the developing device 15 to this electrostatic latent image, a toner image is formed on the photoreceptor 13 , and the toner image on the photoreceptor 13 is transferred to the secondary transfer belt 2 .

FIG. 2 is a schematic enlarged configuration diagram showing one image forming unit of the image forming section 1. As shown in FIG.
As shown in FIG. 2, the developing device 15 has a housing that is long in the longitudinal direction of the photoreceptor 13, and a developing sleeve, a stirring device, and the like are provided inside the housing. The cleaning unit 16 includes a cleaning blade for collecting waste toner, a collection screw, a lubricant application means, and the like. In addition, in FIG. 2, the developing device 15 and the cleaning unit 16 are simply shown.

The charging device 20 is a charging device using a scorotron charging method, and includes a frame 21, a wire 36, and a grid 38.

The frame 21 is an elongated shield case that extends in the longitudinal direction of the charging device 20 and has a photoreceptor side opening 25 that opens toward the photoreceptor 13 . The frame 21 is made of, for example, a stainless steel plate. The wire 36 serves as a discharge electrode and generates discharge. The wires 36 are housed inside the frame 21 , two wires are arranged side by side along the circumferential direction of the photoreceptor 13 , and extend parallel to the axis of the photoreceptor 13 . The wire 36 is, for example, a tungsten base material plated with gold. The grid 38 is an electrode having a mesh plate-like portion 38a (see FIG. 4), and faces the photoreceptor 13. The grids 38 are located between the wire 36 and the photoreceptor 13, and two grids 38 are arranged side by side along the circumferential direction of the photoreceptor 13. The grid 38 is, for example, a mesh type formed by punching a stainless steel plate into a mesh shape.

FIG. 3 is a perspective view of the frame 21. FIG. 4 is a perspective view of the charging device 20. FIG. 5 is a plan view of the charging device 20.
In addition, in FIGS. 4 and 5, only a part of the net plate-like portion 38a is schematically shown as a mesh.
Further, in this specification, in the charging device 20, the photoreceptor 13 side, that is, the photoreceptor side opening 25 side is referred to as the upper side. Further, in the charging device 20, the power feeding side (the side where the connector parts 42a to 42c are located) in the longitudinal direction of the charging device 20 is defined as one side, and the opposite side thereof is defined as the other side.

As shown in FIG. 3, the frame 21 includes a bottom plate 22 and a pair of side plates 23 and 24 extending upward from both side edges of the bottom plate 22. As shown in FIG. A photoconductor-side opening 25 is formed between the opposite ends of the pair of side plates 23 and 24 from the bottom plate 22, that is, on the upper side.A longitudinal opening 26 is formed at the longitudinal end of the frame 21. 27 is formed.

The side plates 23 and 24 have cutout portions 28 formed at their longitudinal ends that open in the horizontal direction. A one-side locking portion 29 for locking the grid 38 is formed at one end of each of the side plates 23 and 24 in the longitudinal direction and extends upward. At the other ends of the side plates 23 and 24 in the longitudinal direction, the other side locking portions 30 for locking the grid 38 are formed to extend upward. A wall plate 31 is erected along the longitudinal direction of the frame 21 at the center of the width direction of the bottom plate 22, and at the other end of the wall plate 31, a second side lock for locking the grid 38 is provided. A pair of portions 30 are formed extending upward. Furthermore, locking holes 35 are formed at both ends of the side plates 23 and 24 in the longitudinal direction.

A connection terminal 32 for applying voltage to the grid 38 is formed extending from one end of the bottom plate 22 to one side. That is, the configuration is such that a voltage is applied to the grid 38 from the connection terminal 32 via the frame 21. The bottom plate 22 is formed with a long hole 33 through which a member (not shown) for cleaning the wire 36 is inserted from the outside and moved in the longitudinal direction. Furthermore, a locking pawl 34 is provided at the longitudinal end of the bottom plate 22 and is inclined so that its tip faces inside the frame 21 .

As shown in FIGS. 4 and 5, the charging device 20 includes blocks 40 and 50 provided at both longitudinal ends of the charging device 20, respectively. Specifically, the blocks 40 and 50 are attached by being press-fitted into the longitudinal openings 26 and 27 (see FIG. 3) of the frame 21, respectively. The blocks 40 and 50 have insulating properties (electrical insulating properties) and are made of resin, for example.

The blocks 40 and 50 have a bottomed box shape with an open top. Guide portions 41 and 51 are provided protruding from both side surfaces of the blocks 40 and 50, respectively. By fitting the guide portions 41 and 51 into the notch portions 28 of the frame 21, movement of the blocks 40 and 50 in the longitudinal direction and the vertical direction of the frame 21 is restricted. At this time, the upper end surfaces of the guide portions 41 and 51 are pressed against the upper inner surface of the notch portion 28, and the lower surfaces of the blocks 40 and 50 are pressed against the upper surface of the bottom plate 22. Further, a locking pawl 34 (see FIG. 3) provided on the bottom plate 22 of the frame 21 locks into a locking portion (not shown) provided on the lower surface of the blocks 40, 50.

Cylindrical connector parts 42a, 42b, and 42c are provided at one end of the block 40 on one side. By press-fitting and attaching the block 40 into the longitudinal opening 26 (see FIG. 3), the connecting terminal 32 is accommodated and arranged within the connector portion 42a.

FIG. 6 is an exploded perspective view showing the block 40, screw member 90, lid 70, and tension member 60. In addition, in FIG. 6, the screw member 90 is shown in a side view to show that it is a stepped screw. FIG. 7 is a plan view showing a state in which the wire 36 is attached between the blocks 40 and 50 provided at both ends of the frame 21 in the longitudinal direction. FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. FIG. 9 is a plan view showing a state in which the lid 70 and the tension member 60 are attached to the blocks 40 and 50 to which the wire 36 is attached.

As shown in FIG. 6, the block 40 is formed so that a portion of the connection terminal 43 for applying voltage to the wire 36 (see FIG. 7) is embedded within the block 40. As shown in FIG. Thereby, the connection terminals 43 are arranged within the connector parts 42b and 42c, respectively. The other end of the connection terminal 43 extends into the block 40 and is provided with a wire attachment portion 44 to which one end of the wire 36 is attached. The wire attachment part 44 is a wire locking part that hooks and locks the wire 36 here.

A boss portion 46 is provided upright on the upper surface of the bottom wall 45 of the block 40 . The boss portion 46 is located approximately at the center within the block 40. A female thread 47 is formed on the upper end surface of the boss portion 46 .

As shown in FIG. 7, a pair of wire attachment parts 52 to which the other end of the wire 36 is attached are provided in the other block 50. As shown in FIG. One end of the wire 36 is attached to one block 40, and the other end of the wire 36 is attached to the other block 50. Further, at the other end of the block 50, a regulating portion 53 is provided that regulates movement of the frame 21 in the longitudinal direction.

As shown in FIGS. 7 and 8, the wire 36 is provided with a tension adjusting spring member 37 at one end thereof. The wire 36 extending from the block 50 on the other side is latched to the wire attachment part 44 via the spring member 37 and is stretched.

As shown in FIG. 6, the charging device 20 includes a tension member 60 having a one-side locking portion 61 that locks one end of the grid 38. As shown in FIG. The tension member 60 includes a horizontal plane part 62 and a through hole 63 formed in the plane part 62. The plane portion 62 has a trapezoidal shape with one side having a smaller width than the other side. The tension member 60 includes a pair of ribs 68 extending upward from the two oblique sides of the trapezoidal plane section 62, and a rib 69 extending upward from the longer bottom side of the plane section 62. . The through hole 63 has a large diameter hole portion 64 and a small diameter hole portion 65 that is connected to one side of the large diameter hole portion 64 and has a smaller diameter than the large diameter hole portion 64 . The tension member 60 is made of metal such as stainless steel, for example.

Two one-side locking portions 61 are provided at one end of the tensioning member 60 in correspondence with each grid 38 in a row in the width direction. Specifically, the one-side locking portion 61 is provided at one end of the pair of ribs 68, respectively. Further, the tension member 60 includes regulating portions 67 at both end portions of the plane portion 62 for regulating the rotation (tilt) of the screw member 90 about the axis. The restriction portion 67 comes into contact with a stopper 74 provided on the top surface of the lid 70, so that rotation of the tension member 60 in the horizontal plane is restricted.

As shown in FIG. 9, the tension member 60 is arranged so that its outline is inside the outline of the block 40 on one side when viewed from the photoreceptor 13 (see FIG. 2) side. In other words, the entire circumference of the tension member 60 is located inside the outline of the block 40 in the plan view.

As shown in FIG. 4, one end of the grid 38 is connected to one side locking part 61 of the tension member 60 (see FIG. 6) and one side of the frame 21 via a tension adjustment spring member 39. It is locked to the side locking part 29 (see FIG. 3). The other side of the grid 38 is locked to the other side locking part 30 (see FIG. 3) of the frame 21.

FIG. 10 is a cross-sectional view taken along the line XX in FIG.
As shown in FIG. 10, the tension member 60 is attached to a portion of the block 40 closer to the photoreceptor 13 (see FIG. 2) than the wire 36, here above. Specifically, the tension member 60 is attached to the upper end surface of the boss portion 46 of the block 40. The upper end surface of the boss portion 46 is located above the wire attachment portion 44. Here, the tension member 60 is attached to the upper end surface of the boss section 46 by a screw member 90 that is screwed into a female thread 47 formed on the upper end surface of the boss section 46 .

As shown in FIG. 6, the screw member 90 is a stepped screw having a head 91, a shaft portion 93 in which a male thread 92 is formed, and a stepped portion 94 provided between the head 91 and the shaft portion 93. be. The stepped portion 94 is formed to have a smaller diameter than the head 91 and a larger diameter than the shaft portion 93. The large diameter hole 64 of the tension member 60 is formed to have a larger diameter than the head 91 of the screw member 90. The small diameter hole 65 of the tension member 60 is formed to have a smaller diameter than the head 91 of the screw member 90 and a slightly larger diameter than the stepped portion 94.

As shown in FIG. 10, with the screw member 90 screwed to the boss portion 46 of the block 40, the lower end surface of the stepped portion 94 comes into contact with the upper end surface of the boss portion 46. The axial length of the stepped portion 94 is set to be slightly larger than the thickness of the flat portion 62 of the tension member 60. When the charging device 20 is in use, the peripheral edge of the small-diameter hole 65 (see FIG. 6) in the flat surface 62 of the tensioning member 60 is located between the lower end surface of the head 91 of the screw member 90 and the upper end surface of the boss portion 46. It is located in between and movement is restricted. A locking surface 66 that locks onto the outer circumferential surface of the stepped portion 94 is formed on the inner surface of one side of the small diameter hole portion 65 .

As shown in FIGS. 4 to 6, the charging device 20 includes lids 70 and 80 that cover the open sides (upper sides) of the blocks 40 and 50, which are the sides of the photoreceptor 13, respectively. Positioning portions 71 and 81 each having a substantially V-shaped notch are formed on the upper surfaces of the lids 70 and 80, respectively. When the charging device 20 is used, the positioning portions 71 and 81 are configured to come into contact with a positioning reference member (not shown) provided in the image forming unit, so that the position of the charging device 20 with respect to the photoreceptor 13 is determined. ing. Locking claws 72, 82 (see FIG. 4) are formed on both side surfaces of the lids 70, 80, respectively. The locking claws 72 and 82 lock into the locking holes 35 (see FIG. 3) of the frame 21. The lids 70 and 80 have insulating properties and are made of resin, for example.

As shown in FIG. 10, a lid 70 covering the upper side of one block 40 has a hole 73 that exposes a female thread 47 formed in a boss portion 46 of the block 40. As shown in FIG. Here, the inner diameter of the hole 73 is larger than the outer diameter of the boss 46 . Therefore, the hole portion 73 exposes the entire upper end surface of the boss portion 46. The boss portion 46 is inserted into the hole portion 73. The tension member 60 is arranged to face the surface of the lid 70 that covers the upper side of the block 40 on one side, on the photoreceptor 13 (see FIG. 2) side.

Maintenance of the charging device 20 configured as described above is performed, for example, as follows.
First, by releasing the grid 38 that is locked to the one side locking part 61 of the tension member 60, the one side locking part 29 of the frame 21, and the other side locking part 30 of the frame 21, Grid 38 is removed from charging device 20 .

Subsequently, the operator slides the tension member 60 to one side (power feeding side). Accordingly, the head 91 of the screw member 90 moves relatively from the small diameter hole 65 to the large diameter hole 64 of the tension member 60. Thereby, the operator can remove the tension member 60 from the charging device 20 by moving the tension member 60 upward.

When the tension member 60 that was placed facing the top surface of the lid 70 is removed, the operator releases the locking claw 72 from the locking hole 35 to remove the lid 70 from the block 40. Can be removed. Subsequently, the operator removes the wire 36 from the charging device 20 by releasing the wire 36 from the wire attachment portion 44 of the block 40 .

Thereafter, the operator attaches, for example, a new wire 36 and grid 38 to the charging device 20 by the reverse procedure of the above-described removal procedure.

As described above, the charging device 20 according to the present embodiment includes the blocks 40 and 50 provided at both ends in the longitudinal direction, the wire 36, and the grid 38 located between the wire 36 and the photoreceptor 13. . The charging device 20 also includes a tension member 60 having a one-side locking portion 61 that locks one end of the grid 38 . The tension member 60 is attached to a portion of the block 40 on one side closer to the photoreceptor 13 than the wire 36 .

In this configuration, the tension member 60 having the one-side locking portion 61 is provided at a portion of the block 40 located above the wire 36. Therefore, a sufficient insulation distance between the one-side locking portion 61 and the wire 36 can be provided in the vertical direction. Therefore, the charging device 20 does not increase in size in its longitudinal direction or in a direction perpendicular to the longitudinal direction along the surface of the photoreceptor 13, and it is possible to suppress the charging device 20 from increasing in size. Furthermore, maintenance such as replacement can be performed by removing the grid 38 and the wire 36 from the charging device 20 in this order, thereby ensuring maintainability. In other words, it is possible to provide the charging device 20 that can suppress the increase in size while ensuring maintainability.

Further, in the present embodiment, the outline of the tension member 60 is arranged inside the outline of the block 40 on one side when viewed from the photoreceptor 13 side. With this configuration, the tension member 60 can be made smaller.

Further, in this embodiment, the blocks 40 and 50 have a bottomed box shape with an open upper side, and wire attachment parts 44 and 52 to which the wire 36 is attached are provided in the blocks 40 and 50. This configuration allows the wire 36 to be securely mounted within the blocks 40,50.

Further, this embodiment includes a frame 21 extending in the longitudinal direction of the charging device 20, and the blocks 40 and 50 are press-fitted into longitudinal openings 26 and 27 formed at the longitudinal ends of the frame 21. installed. With this configuration, the blocks 40, 50 can be reliably attached to the longitudinal ends of the frame 21.

Further, in this embodiment, the other side locking part 30 that locks the other side end of the grid 38 is provided at the end of the frame 21 on which the other side block 50 is attached. In this configuration, the block 50 on the other side is used for attachment of the wire 36 and is not used for locking the grid 38. Therefore, the block 50 on the other side can be made smaller.

Further, in this embodiment, one side of the grid 38 is locked to the one side locking part 29 via the spring member 39, and the other side of the grid 38 is locked to the other side locking part 30. With this configuration, the grid 38 can be mounted with appropriate tension by the spring member 39. Therefore, the grid 38 can be stretched at an appropriate position without bending, and sufficient durability can be ensured. Also,

Further, in this embodiment, the boss portion 46 is erected on the surface of the bottom wall 45 of the one side block 40 on the photoreceptor 13 side, and the tension member 60 is attached to the end surface of the boss portion 46 on the photoreceptor 13 side. is attached to. With this configuration, a large space can be secured in the block 40 on one side for attaching the wire 36 and locking the grid 38.

Further, in this embodiment, the lid 70 that covers the photoreceptor 13 side of one block 40 has a hole 73 that exposes the end surface of the boss portion 46 on the photoreceptor 13 side. Further, the tension member 60 is arranged to face the surface of the lid 70 that covers the photoreceptor 13 side of the one block 40 on the photoreceptor 13 side. In this configuration, the lid 70 can be fixed by attaching the tensioning member 60 to the boss portion 46 and restricting movement of the lid 70 toward the photoreceptor 13 by the tensioning member 60.

Further, in the present embodiment, the tension member 60 is attached to the end surface of the boss portion 46 on the photoreceptor 13 side by a screw member 90 that screws into the female thread 47 formed on the end surface of the boss portion 46 on the photoreceptor 13 side. ing. The screw member 90 is a stepped screw having a stepped portion 94 having a smaller diameter than the head 91 and a larger diameter than the shaft 93 between the head 91 and a shaft 93 in which a male thread 92 is formed. The tension member 60 has a locking surface 66 that locks onto the outer circumferential surface of the stepped portion 94 . In this configuration, the tensioning member 60 can be attached to the boss portion 46 by locking the locking surface 66 of the tensioning member 60 to the outer peripheral surface of the stepped portion 94 of the screw member 90. Moreover, by separating the locking surface 66 of the tension member 60 from the outer peripheral surface of the stepped portion 94 of the screw member 90, the tension member 60 can be removed from the boss portion 46. Therefore, the tension member 60 and the lid 70 can be easily attached and removed without fastening and unfastening the screw member 90. Therefore, maintenance can be performed without applying a load due to fastening and unfastening to the part (female thread 47) into which the screw member 90 is threaded.

Furthermore, in this embodiment, the tension member 60 is made of metal. In this configuration, the tension member 60 has increased strength, so that it can sufficiently cope with the force applied during maintenance and the load due to the tension of the grid 38, and sufficient durability can be ensured.

Further, in this embodiment, two grids 38 are provided, and two one-side locking portions 61 are provided on the tension member 60, corresponding to each of the two grids 38. With this configuration, one end of each of the two grids 38 can be locked by one tension member 60 in a compact configuration.

Further, in this embodiment, the image forming apparatus 100 is configured to include the charging device 20 described above. Thereby, it is possible to provide the image forming apparatus 100 including the charging device 20 that can suppress the increase in size while ensuring maintainability.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be modified as appropriate without departing from the spirit thereof. Additionally, some of the configurations of the embodiments described above can be added, deleted, or replaced.

For example, in the embodiment described above, since the charging device 20 is installed directly below the photoreceptor 13, the side of the photoreceptor 13 in the charging device 20 is on the upper side, but the present invention is not limited thereto. The installation position of the charging device 20 with respect to the photoconductor 13 can be set arbitrarily, and the side of the photoconductor 13 in the charging device 20 is determined according to the installation position of the charging device 20 with respect to the photoconductor 13.

Further, in the embodiment described above, the charging device 20 has two wires 36 and two grids 38, but the present invention is not limited to this. The number of wires 36 and grids 38 does not necessarily have to be two, and may be one, three or more. When there is only one grid 38 , for example, it is preferable that the frame 21 is not provided with the one-side locking portion 29 and one end of the grid 38 is locked only with the one-side locking portion 61 of the tension member 60 . Further, when there is one grid 38, for example, it is preferable that two tension members 60 are provided and the frame 21 is provided with two wall plates 31.

Furthermore, in the embodiment described above, the locking surface 66 that locks on the outer circumferential surface of the stepped portion 94 is located on the inner surface of one side of the small diameter hole portion 65 of the through hole 63 formed in the flat portion 62 of the tension member 60. formed, but is not limited to this. The locking surface 66 may be formed on the inner surface of one side of a notch formed in the flat part 62 of the tension member 60.

Further, in the embodiment described above, the tension member 60 is attached to the upper end surface of the boss section 46 by the screw member 90 that is screwed into the female thread 47 formed on the upper end surface of the boss section 46. It is not something that will be done. The tension member 60 may be attached to the upper end surface of the boss portion 46 by, for example, having a lower portion fitted into a hole formed in the upper end surface of the boss portion 46, or by a pin-shaped member having a lower portion buried in the boss portion 46. good.

13 Photoreceptor (charged body)
20 Charging device 21 Frame 26 Longitudinal opening 27 Longitudinal opening 29 One-side locking portion 30 Other-side locking portion 36 Wire 38 Grid 39 Spring member 40 Block 44 Wire attachment portion 46 Boss portion 47 Female thread 50 Block 52 Wire attachment Part 60 Tension member 61 One-side locking portion 66 Locking surface 70 Lid 73 Hole 90 Screw member 91 Head 92 Male thread 93 Shaft portion 94 Step portion 80 Lid 100 Image forming device

Claims (11)

A charging device that charges a charged object,
an insulating block provided at both ends of the charging device in the longitudinal direction;
A wire that generates electrical discharge,
a grid located between the wire and the charged object;
a tension member having a one-side locking part that locks one end of the grid,
The tension member is attached to a portion of the block on one side that is closer to the charged object than the wire, and
A boss portion is erected on the surface of the bottom wall of the block on one side facing the charged object,
The tension member is attached to an end surface of the boss portion on the side of the charged object,
a lid that covers the charged object side of the block;
The lid that covers the charged object side of the block on one side has a hole that exposes the end surface of the boss portion,
In the charging device, the tension member is disposed to face a surface of the lid that covers the charged object side of one of the blocks on the charged object side. A charging device that charges a charged object,
an insulating block provided at both ends of the charging device in the longitudinal direction;
A wire that generates electrical discharge,
a grid located between the wire and the charged object;
a tension member having a one-side locking part that locks one end of the grid,
The tension member is attached to a portion of the block on one side that is closer to the charged object than the wire, and
A boss portion is erected on the surface of the bottom wall of the block on one side facing the charged object,
The tension member is attached to an end surface of the boss portion on the side of the charged object,
The tension member is attached to the end surface of the boss portion by a screw member that engages with a female thread formed on the end surface of the boss portion,
The screw member is a stepped screw having a stepped portion between a head and a shaft portion in which a male thread is formed, and a step portion having a smaller diameter than the head portion and a larger diameter than the shaft portion;
The tension member is a charging device having a locking surface that locks on the outer circumferential surface of the stepped portion. A charging device that charges a charged object,
an insulating block provided at both ends of the charging device in the longitudinal direction;
A wire that generates electrical discharge,
a grid located between the wire and the charged object;
a tension member having a one-side locking part that locks one end of the grid,
The tension member is attached to a portion of the block on one side that is closer to the charged object than the wire, and
A boss portion is erected on the surface of the bottom wall of the block on one side facing the charged object,
The tension member is attached to an end surface of the boss portion on the side of the charged object,
Two grids are provided,
In the charging device, two of the one-side locking portions are provided on the tension member, corresponding to each of the two grids. The charging device according to any one of claims 1 to 3, wherein the tension member has an outline arranged inside an outline of the block on one side when viewed from the side of the charged object. 4. The block according to claim 1, wherein the block has a bottomed box shape with an opening on the side of the charged object, and a wire attachment part to which the wire is attached is provided in the block. Charging device. a frame extending in the longitudinal direction of the charging device;
The charging device according to any one of claims 1 to 3, wherein the block is attached by being press-fitted into a longitudinal opening formed at a longitudinal end of the frame. 7. The charging device according to claim 6, further comprising a second side locking part for locking the other side end of the grid, provided on the other side of the frame on the side where the block is attached. The charging device according to claim 7 , wherein one side of the grid is locked to the one-side locking portion via a spring member, and the other side of the grid is locked to the other-side locking portion. The charging device according to any one of claims 1 to 8, wherein the tension member is made of metal. A charging device that charges a charged object,
an insulating block provided at both ends of the charging device in the longitudinal direction;
A wire that generates electrical discharge,
a grid located between the wire and the charged object;
a tension member having a one-side locking part that locks one end of the grid,
The tension member is attached to a portion of the block on one side that is closer to the charged object than the wire, and
Two grids are provided,
In the charging device, two of the one-side locking portions are provided on the tension member, corresponding to each of the two grids. An image forming apparatus comprising the charging device according to any one of claims 1 to 10.

Images