JP3259244B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as an electrostatic copying machine, an electrostatic printer or an electrostatic facsimile.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrostatic copying machine, an electrostatic printer or an electrostatic facsimile, a photosensitive drum having a photosensitive member disposed on an outer peripheral surface is used.
The photoreceptor drums are rotatably supported on side walls of the image forming apparatus arranged at intervals from each other or on both side walls of an image forming unit supported by the image forming apparatus main body. The photoconductor drum is required to rotate as smoothly as possible without eccentricity (without blurring) while being supported by the side wall. In particular, in a known color image forming apparatus having four image forming units having toners of different colors from each other, the eccentricity of each photosensitive drum is a major cause of color misregistration. Requires exceptional precision. That is,
In the color image forming apparatus according to the above aspect, each of the photosensitive drums can be easily and accurately positioned at a predetermined axial center, and the horizontal parallelism can be easily and accurately secured. Is particularly required.

A typical example of a conventional image forming apparatus is a mechanism in which bearings are supported at both ends of a shaft provided on a photosensitive drum, and are rotatably supported on a side wall via a bearing case. For example, JP-A-4-671
No. 91). The photoreceptor drum includes a hollow cylindrical drum main body having a photoreceptor disposed on an outer peripheral surface thereof and flange members press-fitted into inner peripheral surfaces at both axial ends of the drum main body. The shaft extends through each of the flange members and bearings are supported at opposite ends of the shaft. The photosensitive drum is rotatably supported on the side wall by rotatably supporting each of the bearings on the corresponding side wall via a bearing case.

[0004]

In the above-described conventional image forming apparatus, the distance between the inner peripheral surfaces of the axially opposite ends of the drum main body and the respective outer peripheral surfaces of the flange members, and the distance between the flange members, Clearance fits between the inner peripheral surface and the outer peripheral surface of the shaft, between the outer peripheral surface of the shaft and each inner ring of the bearing, and between each outer ring of the bearing and the inner peripheral surface of the bearing case. ing. In this way, there are many places where play is likely to occur due to the large number of loose fit parts, and if the photosensitive drum is driven to rotate while being supported on the side wall, blurring, that is, eccentricity increases, There is a problem with. As a result, it can be said that it is difficult to apply the present invention to the color image forming apparatus of the above-described embodiment, in which the accuracy with respect to the eccentricity is particularly required. Further, the photosensitive drum must be supported on the corresponding side wall by an axial fitting operation, which makes the supporting operation difficult. The replacement work is also difficult due to the difficulty of the support work. Furthermore, there are also problems that the number of parts is large, the configuration is complicated, and the manufacturing cost is high.

[0005] The present invention has been made in view of the above fact, this one of its purpose, which can sufficiently reliably prevent eccentricity of the photosensitive drum by a compact structure
In addition to the above, it is also necessary to facilitate the positioning of the charger.
Possible to, is to provide a new and improved image forming apparatus. Another object of the present invention is to provide a compact configuration.
To ensure that the eccentricity of the photoconductor drum is sufficiently ensured by
In addition to being able to
New and improved, making it easy to place in between
To provide an improved image forming apparatus. Further of the present invention
Another purpose is to use a compact structure
In addition to being able to reliably prevent eccentricity,
In addition, secure the charger to the imaging unit easily and securely.
New and improved image forming equipment
Is to provide.

[0006]

According to the present invention, a photoreceptor drum including a hollow cylindrical drum body having a photoreceptor disposed on an outer peripheral surface is rotated between a pair of opposed side walls at intervals.
In an image forming apparatus, which is freely supported, and an image forming element cooperating with the photosensitive drum is arranged around the photosensitive drum, in an outer peripheral surface of both ends of the hollow cylindrical drum main body, Each bearing is press-fitted , and the outer peripheral surface of the photosensitive drum is connected to each of the side walls via the bearing.
Directly supported, the imaging element is disposed between each of the bearings , the imaging element including a stationary element.
And the stationary element is a band mounted between each of the side walls.
An electrical charger, and the charger is provided on the outer peripheral surface of the photosensitive drum.
At a distance, linearly extending in the axial direction of the photosensitive drum.
Existing shield members, and provided at both ends of the shield member.
And each of the end blocks
Is a direction substantially perpendicular to the direction in which the shield member extends.
And extends substantially tangentially to the outer peripheral surface of the photosensitive drum.
And more radially than the corresponding outer ring of the bearing
Removably supported on the corresponding side wall at the outer top
Is, the image forming apparatus characterized by, is provided.

In the above invention, since the photosensitive drum is directly supported on the corresponding side wall via each of the bearings pressed into the outer peripheral surfaces of both ends of the drum body, the conventional image forming apparatus having the shaft is provided. The clearance fit is minimized as compared with, and the places where play is likely to occur due to this are minimized, and blurring or eccentricity during rotation of the photosensitive drum is sufficiently reliably prevented. You. as a result,
The image forming apparatus according to the present invention is also suitably used for the color image forming apparatus of the above-described embodiment, in which precision with respect to eccentricity is particularly strictly required. In the above invention,
Since the image forming element cooperating with the photosensitive drum is disposed between each of the bearings, it is easy to directly support the outer peripheral surface of the photosensitive drum with the bearings while making the entire apparatus compact without increasing the size. It is possible. In the above invention, the image forming element may be a static image.
A stop element, wherein the stationary element is located on each of the side walls.
A charger mounted between the photosensitive drums.
The axis of the photosensitive drum is spaced apart from the outer peripheral surface of the ram.
Member extending linearly in the direction, and the shield portion
End blocks disposed at both ends of the material.
Each of the blocks is arranged in the direction in which the shield member extends.
In a direction substantially perpendicular to the outer peripheral surface of the photosensitive drum.
Extending tangentially above and outside the corresponding bearing
On the corresponding side wall at the upper part radially outward from the ring
It is configured to be detachably supported. shield
End blocks at both ends of the member are in the direction in which the shield member extends
Bearings that extend in a direction perpendicular to
Corresponding side wall at the upper part radially outward of the outer ring of
It is configured to be supported by the
And a charger is placed between each of the bearings.
Can be easily installed.

[0008]

[0009]

[0010]

[0011]

[0012]

According to the present invention, in addition to the above configuration,
A charging wire disposed to extend within and along the shield member, one end of the charging wire being oriented from the direction in which the shield member extends within one of the end blocks. The end of the charging wire is changed and locked in a position extending substantially toward the one extending direction of the end block, and the other end of the charging wire faces from the extending direction of the shield member within the other of the end block. Is changed to be substantially locked at a position extending toward the other extension direction of the end block via a tension spring member. In the above invention,
In spite of the fact that the overall length of the charger is restricted to be short, the charging wire can be securely extended, and the charger can be easily arranged between the bearings.

According to the present invention, in addition to the configuration described above, each of the end blocks is formed with a supported portion projecting from an outer end in the extending direction of the shield member.
A support portion capable of receiving and supporting the corresponding supported portion detachably from above is provided on the inner side of each of the side walls opposite to each other and radially outward of the outer ring of the corresponding bearing. The image forming apparatus is provided, wherein the charger is supported between each of the side walls by disposing the supported portion of each of the end blocks into the corresponding support portion from above. In the above invention, by fitting each supported portion of the end block into the corresponding support portion from above, it is possible to easily and reliably position the charger and to arrange the charger between the bearings. Easily possible.

According to the present invention, in addition to the above configuration,
An imaging unit with each of the side walls, and side plates spaced apart from each other, such that an axial portion of each of the bearings protrudes from a corresponding outer end of the side wall. Bearing means are removably disposed on each of the side plates, and the image forming unit is supported between the side plates by the part of each of the bearings being supported by the corresponding bearing means. Each of the bearing means passes through the center of the shaft in a region below the horizontal line passing through the center of the bearing on the outer peripheral surface of the corresponding bearing as viewed in the axial direction of the photosensitive drum. A lower bearing member having a pair of support surfaces formed so as to be capable of supporting two points sandwiching the vertical line by point contact, and at least one of an outer peripheral surface of the bearing and a region above the horizontal line; Holds points by point contact An upper bearing member having at least one pressing surface formed so as to have a pressing piece detachably mounted on each of the upper bearing members, and each of the upper bearing members being mounted on the corresponding side plate. In this state, each of the pressing pieces presses the corresponding supported portion of the end block from above, thereby fixing the charger to the image forming unit in a detachable manner. . In the above invention, it is possible to easily and surely fix the charger arranged between the bearings to the image forming unit. This fixing operation is performed simultaneously with the operation of attaching each of the upper bearing members to the corresponding side plate, and is therefore very easily performed.

According to the present invention, in addition to the above configuration,
A gap is formed between the outer end of each of the end blocks of the charger and the inner end of the support on each of the corresponding side walls opposite the outer end of the end block, With each of the upper bearing members mounted on the corresponding side plate, each of the holding pieces separates into the gap between the outer end of each of the end blocks and the corresponding inner end of the support. An image forming apparatus that can be freely inserted is provided. In the above invention, each of the pressing pieces facilitates the positioning when the supported portion of the corresponding end block is pressed from above. Therefore, the fixing operation of the charger arranged between each of the bearings to the image forming unit is more easily and reliably performed.

[0017]

[0018]

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an image forming apparatus constructed according to the present invention will be described below in detail with reference to the accompanying drawings.

First, an outline of a portion according to the present invention in an electrostatic copying machine which is an image forming apparatus (not shown) will be described. Referring to FIGS. 1, 2 and 5, the image forming unit 2 includes an image forming unit housing 4. Between the side walls 6 and 8 of the imaging unit housing (hereinafter simply referred to as “housing”) 4, a photosensitive drum 10 has a bearing 1.
It is rotatably supported via 2 and 14. The photosensitive drum 10 is rotated counterclockwise in FIGS. A developing housing 17 of a developing means 16 is detachably mounted on the housing 4. Photoconductor drum 1
An image forming element that cooperates with the photosensitive drum 10 is arranged around 0. The imaging element comprises a rotating element and a stationary element. The rotating element includes a cleaning fur brush 18, a developing roller 20, and a transfer roller 22. The stationary elements are the cleaning seal 24, the cleaning blade 26, the static elimination lamp 2
8 and a charger (charging corona discharger) 30. These imaging elements consist of bearings 12 and 14
It is located between them. In FIG. 5, reference numeral 31 denotes a lid member, which is detachably attached to the housing 4 so as to cover an upper opening of the housing 4.

Referring to FIG. 12, bearings 12 and 1
4 is disposed so as to protrude from the outer ends of the side walls 6 and 8 in the axial direction. In an electrostatic copying machine (not shown), a rear side plate 32 and a front side plate 34 are disposed so as to face each other with a space therebetween. A bearing means 36 is provided on the rear side 32 of the side plate.
Further, bearing means 38 are provided at the front side plate 34 so as to be detachable. The projections of the bearings 12 and 14 are supported by the corresponding bearing means 36 and 38, so that the imaging unit 2 is detachably supported between the rear side plate 32 and the front side plate 34. Below the image forming unit 2, a copy paper transport belt mechanism 40, a part of which is shown in FIGS. 17 to 19, is disposed, and the transfer roller 22 is disposed on the transport belt mechanism 40. I have.

Next, the configuration according to the present invention will be described in detail. First, mainly FIGS. 20 to 27 (and FIGS. 3 to 5)
The housing 4 will be described with reference to FIG. FIG.
In FIG. 24 and FIG. 24, reference symbol O indicates the axis or center of the photosensitive drum 10 mounted on the housing 4 as described later in detail. For example, the housing 4 which can be integrally molded from a synthetic resin such as an ABS resin is shown in FIG.
It has a substantially rectangular shape when viewed from a plane as shown at 0,
It has a side wall (rear) 6 and another side wall (front) 8 spaced from the side wall 6. Several frames connecting them extend between the side walls 6 and 8. That is, when the housing 4 is viewed from the front to the back in FIG. 24 (the direction of the axis O of the photosensitive drum 10), the side wall 6 and the side wall 8
Frames 42 and 44 extend to left and right portions of the upper end of the frame. When viewed in the same direction, frames 46 and 48 extend slightly below the middle portion in the vertical direction on the right side, and both ends in the longitudinal direction are side walls via the other frames 50 and 52. 6 and the side wall 8.

As can be easily understood from FIG. 25, the frame 42 has a lower portion extending in the vertical direction at a predetermined thickness, and a horizontal portion in the width direction of the housing 4 (horizontal direction in FIG. 25) at a predetermined thickness. It has a cross-sectional shape consisting of an extending upper portion, and an intermediate portion extending between the upper portion and the lower portion at an angle. Frames 44 and 46
Has a plate-like cross-sectional shape extending in the vertical direction with a predetermined thickness. Further, the frame body 48 has a lower part 48a having a predetermined thickness and extending substantially horizontally in the width direction, an intermediate part 48b extending upward from one end of the lower part 48a (the center part side of the housing 4, that is, one end on the axis O side), It has a cross-sectional shape consisting of an upper portion 48c extending in a substantially semicircular shape from the upper end of the intermediate portion 48b. The semicircular upper portion 48c is positioned so that its open side faces the center of the housing 4. A plurality of openings 48d are formed in the semicircular upper part 48c at intervals in the longitudinal direction. As shown in FIG. 25, the frame body 46 is positioned at a distance below the frame body 44, and to the right of the upper part 48c of the frame body 48 and the right end of the lower part 48a of the frame body 48. It is located at an interval above each other.

As shown in FIGS. 4, 26 and 27, the frames 50 and 52 have a substantially block-shaped cross section. Inclined surfaces 54 and 56 are formed at both ends in the longitudinal direction of the frames 46 and 48, respectively, inside the frames 50 and 52 facing each other. As clearly shown in FIGS. 3 and 23, a space S1 having a gap D1 is formed between the side wall 6 and one end of the frame body 48 at the above-mentioned central portion, and the side wall 8 and the frame body 48 are formed. A space S2 having a gap D2 is formed between the other end and the central portion. Further, the lower end face 5 of the side wall 8 and the frame body 52 facing the side wall 8.
A space S3 having a gap D3 is formed between the space S3 and the space S3. The gap D2 is formed larger than the gap D3.
The spaces S1, S2, and S3 are open at the central portion side and below, and the space S3 is also open at the opposite side (the right side in FIG. 24) of the central portion. As shown in FIG. 24, a notch 57 is formed in the lower right corner of the side wall 8, and the notch 57 exposes most of the end surface 52 a of the frame 50 to the side wall 8 side. In the exposed portion of the end face 52a of the frame body 50, a screw hole 58 extending in the front-back direction (the direction of the axis O) of FIG. 24 is formed. The screw hole 58 is formed by a female screw formed in a metal cylindrical member, and is provided by press-fitting the cylindrical member into a hole formed in the same portion. In the following description, the “screw hole” formed in the synthetic resin member has the same configuration as described above unless otherwise specified, and the description as above is omitted. As can be easily understood from FIGS. 22 and 27, the frames 50 and 5
2, screw holes 51 extending in the width direction are formed on the vertical surface opposite to the central portion.
A screw hole 53 extending in the vertical direction is formed on each of the two horizontal lower surfaces. Each of the screw holes 51 is formed for mounting both ends of a mounting plate 134 for the cleaning blade 26 described later, and each of the screw holes 53 is formed for mounting the cleaning plate 24 for the cleaning seal 24 described later.
16 are formed for mounting both end portions.

A metal rod 60 (shown only in FIGS. 1 and 21) is disposed on the left side of the frame 42 when the housing 4 is viewed in the direction of the axis O. At the same portion of the side wall 6 and the side wall 8, a mounting hole 62 having a common axis is formed, and both ends of the rod 60 correspond to the mounting holes 62.
And is held by a stop ring (not shown) so as not to come off. Further, bosses 64 are formed below the frame 42 and at inner portions of the side walls 6 and 8 facing each other. Each of the bosses 64 having a substantially rectangular parallelepiped shape has a screw hole 66 extending horizontally and in a direction perpendicular to the axis O (the width direction of the housing 4).
Are formed. Each of the rod 60, the boss 64, and each of the screw holes 66 are provided for detachably mounting the developing unit 16 to the housing 4.

Next, before describing the characteristic structure of the side walls 6 and 8 of the housing 4, the photosensitive drum 10 will be described with reference to FIG. 12. The photosensitive drum 10 is formed of, for example, an aluminum alloy or the like. A hollow cylindrical drum main body 11 that can be used; flange members 13 and 15 respectively press-fitted into inner peripheral surfaces of both ends in the axial direction of the drum main body 11;
The drum body 11 includes the above-described bearings (ball bearings) 12 and 14 which are press-fitted to the outer peripheral surfaces of both ends in the axial direction of the drum body 11 respectively. Drum body 11
A photoreceptor is disposed on an outer peripheral surface of the photoreceptor. Flange member 1
Reference numerals 3 and 15 are real shaft members integrally formed from a synthetic resin such as POM. Flange members 13 and 1
5 can of course be formed by a sintered metal or by cutting a metal member. A bearing 12 having an inner ring and an outer ring is provided on the outer peripheral surface of the one end of the drum main body 11 where the flange member 13 is press-fitted.
Is mounted by press-fitting the inner ring to the outer peripheral surface. A stop ring is mounted on the flange member 13 on the outer side in the axial direction of the inner ring of the bearing 12. This prevents the bearing 12 from moving axially outward with respect to the drum body 11. A driven gear 13a is formed integrally with the other end of the flange member 13 in the axial direction. A bearing 14 having an inner ring and an outer ring is provided on the outer peripheral surface of the other end of the drum main body 11 where the flange member 15 is press-fitted.
Is mounted by press-fitting the inner ring to the outer peripheral surface. An outer diameter portion larger than the inner diameter of the inner ring is provided integrally with the flange member 15 on the outer side in the axial direction of the inner ring of the bearing 14. Thereby, the drum body 11 of the bearing 14
Is prevented from moving outward in the axial direction.

Next, FIG. 20, FIG. 23 and FIG.
The side walls 6 and 8 of the housing 4 will be described with reference to FIG. Frames 68 and 70 projecting outward in the direction of the axis O are formed at the upper ends of the side walls 6 and 8, respectively. As shown in FIG. 20, the frame bodies 68 and 70, which are grip portions of the housing 4, form rectangular openings between the side walls 6 and 8, respectively, when viewed from a plane. Supporting surfaces 72 and 74 for the lid member 31 (see FIGS. 3 and 5) are formed at one end of each opening in the width direction so as to cover them and extend substantially horizontally. Holes 76, 77, 78, and 79 for attaching the lid member 31 are formed at both ends in the width direction of the frame bodies 68 and 70, respectively.

The side walls 6 and 8 are configured so that the photosensitive drum 10 can be suitably mounted via bearings 12 and 14. In the side walls 6 and 8, since the configuration of the portion where the photosensitive drum 10 is mounted is substantially the same, the side wall 8 will be described here. The same portions of the side wall 6 are denoted by the same reference numerals, and description thereof will be omitted. A notch 80 is formed in the side wall 8 extending substantially vertically. The notch 80 extends from the opened upper end to the drum body 11.
Are formed so as to extend in parallel vertically downward with a width larger than the diameter of the upper end and have a lower end forming a semicircular closing portion 80a.
The inner diameter of the closing portion 80a is defined to be smaller than the outer diameter of the outer ring of the bearing 14. Outside the closing portion 80a (outside in the direction of the axis O), annular recesses (recesses formed so as to be lower in the inward direction with respect to the outer surface of the side wall 8) 82 and 84 are formed. The annular concave portion 82 has a common axis with the closed portion 80a, has a larger radius than the closed portion 80a, has a semi-circle or larger size, and has a width smaller than the diameter of the concave portion 82 itself. Further, it is formed to have upper ends 82 a and 82 b defined with a width larger than the width of the notch 80.

The recess 82 continues to another recess 86 that extends substantially symmetrically upward along both sides of the notch 80. The other recess 86 having the same depth from the outer surface of the side wall 8 as the recess 80 is separated from the recess extending upward along both sides of the notch 80 from the upper end of the recess 80 with the notch 80 interposed therebetween. It consists of a concave portion that protrudes in the lateral direction. Screw holes 88 for attaching a bearing member 90 to be described later are respectively provided in the concave portions that protrude in the lateral direction. The annular concave portion 84 is formed to have a common axis with the closing portion 80a and to have a radius larger than the closing portion 80a and smaller than the annular concave portion 82. And the annular recess 8
The radius of 4 is formed larger than the outer diameter of the inner ring of the bearing 14. The upper end of the annular concave portion 84 is defined by a portion extending in parallel vertically below the notch 80. The concave portion 84 is formed to prevent the bearing 14 from abutting against the side surface of the inner race when the photosensitive drum 10 is mounted on the side wall 8 as described later. The bottom surfaces of the concave portions 82 and 84 are vertical flat surfaces.

As shown in FIG. 6, a bearing member 90 is detachably mounted in the concave portion 82 of the side wall 8. Referring to FIGS. 28 to 30, a bearing member 90 made of a substantially plate-like member as a whole is made of, for example, PC (polycarbonate).
It is integrally molded from a synthetic resin such as a resin, and has a shape that can be fitted into the recess 82. That is, the bearing member 90
Are an annular portion 92 slightly larger than a semicircle and an annular portion 92
And a mounting portion 94 located above. A support hole 96 that is a through hole is formed in the annular portion 92. Annular part 9
2 and the support hole 96 have a common axis O. The support hole 96 has a diameter capable of being pressed into the outer ring of the bearing 14. The mounting portion 94 includes a portion that extends upward from the upper ends of the annular portion 92 and the support hole 96, and a portion that protrudes in the lateral direction that is apart from the upwardly extending portion.
The notch 80 is provided in a portion extending above the mounting portion 94.
A thicker portion 98 having a smaller width than that of the first embodiment is formed.
The plate thickness portion 98 is provided with a support portion 100 capable of detachably receiving and supporting a supported portion 175 formed on an end block 174 of the charger 30 described later.

The support portion 100 includes a pair of inclined surfaces 102 formed symmetrically with respect to a vertical line passing through the axis O, and a pair of inclined surfaces 1.
02 which is an arc-shaped bottom formed to connect the lower ends of
04. In FIG. 28, each of the inclined surfaces 102 is formed so as to approach the vertical line and to be located on a line (plane) intersecting with the axis O as it extends vertically downward.
Reference numeral 04 denotes an arc shape having a common axis with the axis O of the support hole 96. Each of the inclined surfaces 102 and the bottom surface 104
The width in the axial direction passing through the axis O is substantially constant. Since the support portion 100 is formed on one side of the plate thickness portion 98 in the axial direction passing through the axis O, one side in the axial direction and vertically upward are open. Annular portion 92
Is formed so as to align with the annular recess 82 of the side wall 8, and the mounting portion 94 is formed so as to align with the other recess 86 of the side wall 8.
Each of the laterally extending portions has a mounting hole 10.
6 are formed. These holes 106 align with each of the screw holes 88 in the side wall 8.

Next, the mounting of one end of the photosensitive drum 10 to the side wall 8 will be described with reference to FIGS. The drum body 11 of the photoconductor drum 10 is inserted into the notch 80 of the side wall 8 from above, and positioned on the same axis O as the closing portion 80a. In this state, a portion of the bearing 14 in the axial direction is positioned outside the closing portion 80a in the axial direction. Next, the support hole 96 of the bearing member 90 is inserted into the bearing 1.
4, the bearing member 90 is positioned so as to fit into the annular concave portion 82 and the other concave portion 86 of the side wall 8 while being pressed into the outer ring.
The bearing member 90 is mounted on the side wall 8 with a screw 108. The axially outward movement of the inner ring of the bearing 14 is prevented by the large diameter portion of the flange member 15, and the axially inward movement of the outer ring is prevented by the bottom surface of the concave portion 82 of the side wall 8.
With the above configuration, the eccentricity of the photosensitive drum 10 is reliably prevented. The mounting of the other end of the photosensitive drum 10 to the side wall 6 is performed in the same manner (see FIG. 7). As can be easily seen from FIG. 12, the opposing faces of the side walls 6 and 8 are located axially inwardly of the axially opposing end faces of the bearings 12 and 14. A part of the bearing 12 in the axial direction is disposed so as to protrude from the outer end of the side wall 6, and a part of the bearing 14 in the axial direction is disposed so as to protrude from the outer end of the side wall 8. In this way, the photosensitive drum 10 is detachably and rotatably supported by the side walls 8 and 6.

The details of the constructions of the photosensitive drum and the mounting mechanism thereof are described in Japanese Patent Application Nos. 9-24536 and 9-24537 filed by the present applicant.
Since these are described in detail in the description and drawings of each item, further description is omitted in the specification and drawings.

Referring mainly to FIGS. 1 to 5, a cleaning fur brush (hereinafter simply referred to as a "fur brush") 18 as a rotating member is mounted on a rotating shaft 110, and both ends of the rotating shaft 110 are fur brushes. 18 project outward from both ends. The driven gear 1 is provided at one end of the rotating shaft 110.
12 are provided. Fur brush 1 of rotating shaft 110
8 are provided with a bearing member 11 made of synthetic resin.
4 (only shown in FIG. 4) is mounted so as to be relatively rotatable. The fur brush 18 is rotatably mounted on the housing 4 by each of the bearing members 114 being detachably mounted on both ends of the frame 48 of the housing 4. Each of the bearing members 114 is provided by a mounting plate 116.
The lower surface and the surface of the housing 4 on the central portion side (the lower surface in the vertical direction) are pressed. The mounting plate 116 is attached to the lower surface 48 a of the frame body 48 with screws 117 via screw holes 53 on the lower surfaces of the frame bodies 50 and 52 so as to extend substantially in close contact with the lower portion 48 a of the frame body 48. It is detachably mounted. A cleaning seal 24 is attached to the tip of the mounting plate 116. Cleaning seal 2
4 is in contact with the outer peripheral surface of the drum body 11 of the photosensitive drum 10. An arc-shaped portion extending substantially parallel to the outer peripheral surface of the drum main body 11 is formed on a part of the surface on the central portion side (the intermediate surface in the vertical direction) of each of the bearing members 114. I have. A pile-shaped seal member 118 (shown only in FIG. 4) is attached to a surface (upper surface in the vertical direction) of each of the bearing members 114 including the arc-shaped portion on the central portion side. I have. When the photosensitive drum 10 is mounted on the housing 4 as described above, the drum body 1
The outer peripheral surface 1 presses the seal member 118 from the central portion side in the arc-shaped portion (see FIG. 4).

As described above, each of the bearing members 114 is held by the housing 4. The fur brush 18 is positioned in a semicircular upper part 48c of the frame 48 (see FIG. 25). The driven gear 112 at one end of the rotating shaft 110 is located in the space S2 (see FIG. 23), and the other end of the rotating shaft 110 is located in the space S1 (see FIG. 23). All of the fur brush 18, rotating shaft 110 and driven gear 112 will be located between the side walls 6 and 8, and thus between the bearings 12 and 14. As can be easily understood from FIG. 1, since the tip diameter of the driven gear 112 is defined to be smaller than the outer diameter of the fur brush 18, a part of the outer peripheral surface of the fur brush 18 The driven gear 112 does not come into contact with the outer peripheral surface of the drum main body 11 despite being in contact with the surface. The mounting plate 116 mounted on the frame 48 and the cleaning seal 24 are also positioned between the side walls 6 and 8 (the length in the longitudinal direction is set shorter than the interval between the side walls 6 and 8). Reference numeral 120 in FIG. 3 denotes an electrode plate, which is detachably attached to the side wall 6.
The electrode plate 120 has appropriate elasticity and presses the other end of the rotating shaft 110 of the fur brush 18 toward one end thereof. A spherical portion is formed at the tip of the electrode plate 120, that is, at the contact portion with the other end of the rotating shaft 110.

The end surface 52a of the frame 52 of the housing 4
, A gear mounting plate 122 is detachably mounted by screws 124. The screw 124 is locked in a screw hole 58 formed in the end face 52a. Four gears 126, 128, 130 and 132 are rotatably mounted on the gear mounting plate 122. The gears 130 and 132 are formed integrally, and the gears 126 and 128 and the gears 128 and 130 are meshed with each other. The gear 126 is meshed with the driven gear 112 of the fur brush 18. The gear mounting plate 122 and the gears 126 and 128 are located in the space S3.
(See FIG. 23). As shown in FIG. 3, one end of the shaft of the gear 126 is pressed into a support hole formed in the side wall 8, and together with the screw 124, the gear mounting plate 12 is pressed.
2 is held in the above position. This press-fitting is easily performed by utilizing the elasticity of the side wall 8. Gear (input gear) 132
Is exposed to the outside from the space S3 by the notch 57 of the side wall 8, and can be driven and connected to a drive source which may be an electric motor (not shown) via a gear (not shown).

As shown in FIG. 5, a mounting plate 134 is mounted substantially in close contact with the frame 46. Mounting plate 134
Is mounted on the vertical surfaces of the frames 50 and 52 so as to be detachable by screws 136 through the screw holes 51 so as to extend along the longitudinal direction of the frame 46. The mounting plate 134 has a substantially L-shape, and its upper part is inclined so as to become lower as it goes toward the drum body 11. A mounting plate 138 having a substantially L shape is detachably mounted on the inclined upper portion by a screw 140.
The cleaning blade 26 is mounted on the tip of the mounting plate 138. The tip of the cleaning blade 26 is in contact with the outer peripheral surface of the drum main body 11. The mounting plate 134, the mounting plate 138, and the cleaning blade 26 are also positioned between the side walls 6 and 8 (the length in the longitudinal direction is set shorter than the interval between the side walls 6 and 8).

As described above, the rectangular opening formed at the upper end of the housing 4 is covered by the rectangular lid member 31. The two corners of the lid member 31 are placed on the support surfaces 72 and 74 of the housing 4, and four peripheral edges are provided at mounting holes 76, 77, 78 and 79 () formed in the frames 68 and 70. (See FIG. 2). A substantially L-shaped mounting plate 142 is detachably mounted on the lower surface of the lid member 31 with screws 144. The static elimination lamp 28 is attached to the tip of a mounting plate 142 extending toward the drum body 11. The mounting plate 142 and the static elimination lamp 28 also
It is located between the side walls 6 and 8 (their length in the longitudinal direction is set shorter than the distance between the side walls 6 and 8).

Next, the mounting mechanism of the developing means 16 will be described. On the upper part of the developing housing 17 of the developing means 16,
The two locking portions 150 are spaced apart in the longitudinal direction (FIG. 1).
And one of them is shown in FIG. 5). Each of the locking portions 150 has a substantially U-shape, and its open side is directed upward. The developing housing 17 is also provided with two mounting portions 152 spaced from each other in the longitudinal direction. Each of the mounting portions 152 is formed of a plate-like piece that protrudes downward from the lower surface of the developing housing 17, and has a mounting hole. While each of the locking portions 150 is locked to the rod 60 of the housing 4, the developing means 1
6 is rotated counterclockwise in FIG.
Are positioned against the end faces of the corresponding bosses 64 of the housing 4. Each mounting hole of the mounting portion 152 is aligned with the screw hole 66 of the boss 64, and the screw 154 is locked in each of the screw holes 66. Mounted freely. One of the side walls (not shown) of the developing housing 17 is positioned at a distance from the side wall 6 of the housing 4, and the other side wall (not shown) of the developing housing 17 is positioned at a distance from the side wall 8 of the housing 4.

The development housing 17 is provided with a development roller 20 and a toner supply roller 156. The developing roller 20 is mounted on a rotating shaft 158, and both ends of the rotating shaft 158 protrude outward from both ends of the developing roller 20. The developing roller 20 is rotatably supported by the developing housing 17 with its rotating shaft 158 rotatably supported on both side walls (not shown) of the developing housing 17 via bearing members (not shown). One end of the rotating shaft 158 protrudes from one of the side walls toward the side wall 8 of the housing 4, and a driven gear 160 is mounted on the protruding end. The entire developing roller 20 is located between the side walls 6 and 8, and thus between the bearings 12 and 14. As can be easily understood from FIG. 1, since the tip diameter of the driven gear 160 is defined to be smaller than the outer diameter of the developing roller 20, a part of the outer peripheral surface of the developing roller 20 Driven gear 16 despite contact with the
0 does not contact the outer peripheral surface of the drum main body 11.

The toner supply roller 156 is mounted on a rotating shaft 162, and both ends of the rotating shaft 162 are
56 project outward from both ends. The toner supply roller 156 is rotatably supported by the developing housing 17 with its rotating shaft 162 rotatably supported on both side walls of the developing housing 17 via bearing members (not shown). One end of the rotating shaft 162 protrudes from one of the side walls toward the side wall 8 of the housing 4, and a driven gear 164 is mounted on the protruding portion. The rotation shaft 162 protrudes further outward of the side wall 8 of the housing 4, and an input gear 166 is mounted on a protruding end thereof. The rotation shaft 162
A notch 167 is formed in a corresponding portion of the side wall 8 in order to avoid interference with the projection. An idle gear 168 is rotatably disposed on one side of the side wall of the developing housing 17. Driven gear 16 of developing roller 20
0 is meshed with the idle gear 168, and the idle gear 168 is meshed with the driven gear 164 of the toner supply roller 156. The input gear 166 can be drivingly coupled to a drive source which may be an electric motor (not shown) via a gear (not shown). As is clear from the above description, except for the protruding portion of the rotating shaft 162,
The developing means 16, including all components such as the rotating shaft 158, the driven gear 160, etc., will be located between the side walls 6 and 8, and thus between the bearings 12 and 14. It should be noted that the position of the rotating shaft 162 itself is the bearing 1.
The members located radially outward from the outer races 2 and 14 do not necessarily have to be located between the bearings 12 and 14.

Next, a configuration of the charger 30 and a mounting mechanism thereof will be described mainly with reference to FIGS. The charger 30 includes a shield member 170 extending linearly,
End blocks (housings) 172 and 174 provided at both ends of the shield member 170 are included. The shield member 170 is a channel member that can be formed from, for example, a stainless steel plate. For example, end blocks 172 and 174, which can be formed from a synthetic resin such as PC (polycarbonate),
The shield members 170 are attached to both ends of the shield member 170 in a form extending in a direction substantially perpendicular to the extending direction of the shield member 70 and substantially parallel to each other. The lower surface of the charger 30, that is, the lower surface on the open side of the shield member 170, the end blocks 172 and 17
The lower surface of 4 is configured to extend along substantially one plane.

The charger 30 further includes a charging wire 176 disposed linearly extending within the shield member 170 and a grid disposed along the open side of the shield member 170. 178.
One end of the charging wire 176 is locked in the end block 174 at a position which is changed from the direction in which the shield member 170 extends and extends substantially in the direction in which the end block 174 extends. Locking means capable of locking one end of the charging wire 176 is provided in the end block 174 which is a housing, and the charging wire 176 can be turned in direction to extend one end to the locking means. A possible wire extension space is formed. The other end of the charging wire 176 is a coil spring that is a tension spring member at a position in the end block 172 where the direction is changed from the direction in which the shield member 170 extends and extends substantially in the direction in which the end block 172 extends. 180
Is locked through. Locking means for locking one end of the coil spring 180 is provided in the end block 172 which is a housing, and the other end is extended to the other end of the coil spring 180 by changing the direction of the charging wire 176. A wire extension space is formed that can be used.

The end blocks 172 and 174 are integrally formed with supported portions 173 and 175 which protrude outward from the outer end of the shield member 170 in the extending direction and are mutually separated. The supported portions 173 and 175 are shown in FIGS.
As shown in FIG. 28, when viewed in the direction in which the shield member 170 extends, the bearing member 90 (see FIGS. 30) (see FIG. 30). That is, the supported portions 173 and 175 extend as described above with a fixed projection width, and have, at both ends in the extending direction, inclined surfaces 173a and 173a that match the inclined surfaces 102 of the support portion 100 of the bearing member 90, respectively. 175 a is formed, and a bottom surface 173 matching the bottom surface 104 of the support portion 100 is formed on the lower surface.
b and 175b are formed.

With the bearings 12 and 14 supported on the side walls 6 and 8 of the housing 4 via the bearing member 90, the supported portions 173 and 175 are
The charger 30 is supported between the side walls 6 and 8 by fitting the charger 30 from above. The charger 30 is provided on the side wall 6.
And 8 are supported between each of the shield members 17.
0, the charging wire 176 and the grid 178 are positioned so as to extend linearly in the direction of the axis O of the photosensitive drum 10 with a distance from the outer peripheral surface of the drum main body 11, and the end blocks 172 and 174 are shielded. It is positioned so as to extend in a direction substantially perpendicular to the direction in which the member 170 extends and in a direction substantially tangential to the outer peripheral surface of the drum main body 11. Since the support portion 100 of the bearing member 90 is disposed radially outward of the support hole 96 into which the outer ring of the bearing 12 or 14 is fitted, the end block 1
The supported portions 173 and 175 of the bearings 72 and 174 are detachably supported by the support portion 100 (therefore, between the side walls 6 and 8) at an upper portion radially outward of the outer rings of the bearings 12 and 14. As is clear from FIGS. 8 and 9,
End blocks 172 and 174 are located between bearings 12 and 14. In this mounted state, a gap is formed between the outer ends of the end blocks 172 and 174 and the inner ends of the support portions 100 facing the outer ends of the end blocks 172 and 174. The supported portions 173 and 175 are respectively pressed from above by pressing pieces 220 described later.

Next, referring to FIGS. 12 to 16, as described above, the protrusions of the bearings 12 and 14 supported on the side walls 6 and 8 of the housing 4 are mounted on the rear side 32 and the front side 34 of the side plate. The image forming unit 2 including the photoreceptor drum 10 is detachably supported between the rear side plate 32 and the front side plate 34 by being supported by the bearing means 36 and 38.
The bearing means 36 includes a lower bearing member 180 and an upper bearing member 190, each of which can be integrally formed from a synthetic resin such as PC (polycarbonate). The lower bearing member 180 sandwiches a vertical line passing through the axial center O in a region below the horizontal line passing through the axial center O of the bearing 12 on the outer peripheral surface of the bearing 12 when viewed in the axial direction of the photosensitive drum 10. It has a pair of support surfaces 182 and 184 formed so as to be able to support two places by point contact. The lower bearing member 180 is secured to the rear plate 32
Attached to. The upper bearing member 190 has at least one pressing surface formed so as to be able to press at least one position by point contact on the outer peripheral surface of the bearing 12 and above the horizontal line, and in this embodiment, two positions. It has a pair of holding surfaces 192 and 194 formed so as to be held by point contact. The upper bearing member 190 is mounted on an upper portion of the lower bearing member 180 by a screw 196.

The bearing means 38 includes a lower bearing member 200 and an upper bearing member 210, each of which can be integrally molded from a synthetic resin such as PC (polycarbonate). The lower bearing member 200 sandwiches a vertical line passing through the axial center O in a region below the horizontal line passing through the axial center O of the bearing 14 on the outer peripheral surface of the bearing 14 when viewed in the axial direction of the photosensitive drum 10. A pair of support surfaces 202 and 20 each formed so as to support two places by point contact.
Four. The lower bearing member 200 is mounted on the front side plate 34 by screws 206. The upper bearing member 210 has at least one pressing surface formed to be able to press at least one point by point contact on the outer peripheral surface of the bearing 14 and above the horizontal line, and in this embodiment, two points each. It has a pair of pressing surfaces 212 and 214 formed so as to be pressed by point contact. The upper bearing member 210 is mounted on the upper part of the lower bearing member 200 by screws 216.

The details of the structure of each of the above bearing means are described in Japanese Patent Application No. 9-791 filed by the present applicant.
Since it is described in the specification and the drawings of No. 92, further description is omitted in the specification and the drawings.

With the lower bearing member 180 mounted on the rear side plate 32 and the lower bearing member 200 mounted on the rear side plate 34, the imaging unit 2 is lowered to move the bearing 12 outward from the side wall 6 of the bearing 12. Are mounted and supported on the support surfaces 182 and 184 of the lower bearing member 180 by point contact when viewed from the axis O direction, respectively, and outward from the side wall 8 of the bearing 14. Two protruding outer peripheral surfaces are mounted and supported on the support surfaces 202 and 204 of the lower bearing member 200 by point contact when viewed from the axis O direction, respectively. Next, by attaching the upper bearing member 190 to the lower bearing member 180, the pressing surface 19
2 and 194 press the outer peripheral surface of the bearing 12 at two locations from above, and by attaching the upper bearing member 210 to the lower bearing member 200, the pressing surfaces 212 and 2
14 presses two locations on the outer peripheral surface of the bearing 14 from above.

Referring to FIGS. 10 and 11, a holding piece 220 is detachably attached to upper bearing member 210 by a screw 222. The pressing piece 220 can be integrally formed from a synthetic resin such as POM, for example. The holding piece 220 has a rectangular shape when viewed in the direction of the axis O of the photosensitive drum 10, and has a substantially inverted U shape when viewed in a horizontal direction orthogonal to the direction of the axis O. Of the holding piece 220,
The base portion 224 extending downward is provided with the upper bearing member 210.
The holding part 226 which is attached to one side of the base plate by a screw 222 and protrudes in an arc shape from the upper end of the base 224 and extends downward has a plate shape. Upper bearing member 21
0 is attached to the lower bearing member 200,
The holding portion 226 of the charger 20 is detachably inserted into a gap between the outer end of the end block 174 of the charger 30 and the inner end of the support portion 100 of the bearing member 90, and the lower end of the holding portion 226 is The supported portion 175 is pressed from above. An elastic force acts on this presser due to the above-described material and the above-described configuration of the presser piece 220. Upper bearing member 1
Since substantially the same pressing piece 220 is attached also to the 90, the supported portion 17 of the end block 172 of the charger 30 is mounted.
3 presses from above as described above. As described above, the charger 30 is detachably fixed to the predetermined position of the image forming unit 2.

As described above, the image forming unit 2 is mounted between the rear side plate 32 and the front side plate 34 of the electrostatic copying machine. Below the image forming unit 2, a copy paper transport belt mechanism 40 is disposed. Referring to FIGS. 17 to 19, endless transport belt mechanism 40 includes a pair of side plates 230 arranged at intervals in the direction of axis O of photosensitive drum 10, and one end and the other end (not shown) of each of side plates 230. , A driving roller and a driven roller (not shown), a conveyor belt 232 wound around the rollers, and a transfer roller 22 disposed between the side plates 230. The transfer roller 22 is mounted on a rotating shaft 234, and both ends of the rotating shaft 234 are supported by corresponding side plates 230 via bearing members 236.
Rollers 238, which are spacers, are mounted on both ends of the rotating shaft 234. Each of the bearing members 236 is vertically movably mounted in a mounting hole 240 formed in the corresponding side plate 230 and is urged upward by a coil spring 242. As a result, the roller 238 is pressed against the outer peripheral surface of the drum main body 11, and the transfer roller 22 is pressed against the outer peripheral surface of the drum main body 11 via the transport belt 232. Side plate 2
The spacing of each of the bearings 30 is set smaller than the spacing between the bearings 12 and 14, and thus is positioned inside the bearings 12 and 14. The width of the transport belt mechanism 40 including the transfer roller 22 (the photosensitive drum 1
0 (the width in the direction of the axis O) is set smaller than the interval between the bearings 12 and 14. The transfer roller 22 is rotated by being pressed against the belt 232. In some embodiments, the transfer roller 22 is driven by a driven gear. In this case, the diameter of the addendum circle of the driven gear is defined to be smaller than the outer diameter of the transfer roller 22.

As is clear from the description of the above embodiment,
The image forming elements such as the cleaning fur brush 18, the developing roller 20, the transfer roller 22, the cleaning seal 24, the cleaning blade 26, the static elimination lamp 28, and the charger (charging corona discharger) 30 are detachable to corresponding frame means. Supported. The frame means on which the imaging element is supported comprises a bearing 12
And 14 are disposed inside the axially opposed end faces of each of them. 2, 5 and 21, the frame means on which the cleaning fur brush 18 is supported are the frames 48, 50 and 52 of the housing 4, which are the side walls 6 and 8
Of the bearings 12 and 14 and thus between the end faces of each of the bearings 12 and 14. The frame means on which the developing roller 20 is supported is the developing housing 1
7, the developing housing 17 is positioned between the side walls 6 and 8. The frame means on which the transfer roller 22 is supported is each of the side plates 230 (see FIGS. 17 to 19), and each of the side plates 230 is disposed between the side walls 6 and 8.

The frame means on which the cleaning seal 24 is supported via the mounting plate 116 and the frame means on which the cleaning blade 26 is supported via the mounting plates 138 and 134 are frames 46, 50 and 52, respectively. They are located between the side walls 6 and 8. The frame means on which the charger 30 is supported via the supported portions 173 and 175 is the support portion 100 of each of the bearing members 90 mounted on the side walls 6 and 8, and the support portion 10
Each of the zeros is substantially located between the end faces of each of the bearings 12 and 14. Since the frame means is disposed inside the end faces of each of the bearings 12 and 14 as described above, it is easy to position the imaging element supported thereon between the end faces of each of the bearings 12 and 14. It is possible.

The preferred embodiment of the image forming apparatus constructed according to the present invention has been described with reference to the accompanying drawings. However, the present invention is not limited to the above embodiment, and departs from the scope of the present invention. It should be understood that various changes or modifications may be made without departing from the invention. For example, in the above-described embodiment, the photosensitive drum 2 is supported between the side wall 22 of the image forming unit housing and the other side wall, and further, the rear side plate 4 and the front side plate of the electrostatic copying machine as an image forming apparatus. It is supported between the side walls of the image forming apparatus, but it is needless to say that some embodiments are directly supported between the side walls (between the side plates and the front of the side plates) of the image forming apparatus.

[0055]

According to the image forming apparatus of the present invention, the eccentricity of the photosensitive drum can be sufficiently and reliably prevented by a compact structure. Therefore, the image forming apparatus of the present invention is also suitably used for the color image forming apparatus of the above-described embodiment, in which the precision with respect to eccentricity is particularly strictly required.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an embodiment of an image forming unit included in an image forming apparatus configured according to the present invention, mainly showing a layout of a rotating element.

FIG. 2 is a schematic top view of the image forming unit shown in FIG. 1, mainly showing a layout of rotating elements.

FIG. 3 is a schematic cross-sectional view taken along the line AA of FIG. 2, mainly showing a cleaning fur brush and a driving system thereof.

FIG. 4 is a schematic cross-sectional view taken along the line BB of FIG. 2 and mainly shows a bearing portion of the cleaning fur brush.

FIG. 5 is a schematic cross-sectional view taken along the line CC of FIG. 2, showing a layout of the entire image forming element in the image forming unit.

FIG. 6 is a schematic cross-sectional view taken along the line DD of FIG. 2 and mainly shows a mounting structure of a bearing and a charger.

FIG. 7 is a schematic cross-sectional view taken along the line EE in FIG. 2, and is a schematic cross-sectional view mainly showing a mounting structure of a bearing and a charger.

FIG. 8 is a schematic longitudinal sectional view of FIG. 6, mainly showing a mounting structure of a charger.

FIG. 9 is a schematic top view of FIG. 8, with each of the bearings broken away.

FIG. 10 is a schematic cross-sectional view taken along the line DD in FIG. 2 and mainly shows a positional relationship between a bearing and an upper bearing member.

FIG. 11 is a schematic cross-sectional view taken along the line FF of FIG. 10 and mainly illustrates a mounting structure of a holding piece.

FIG. 12 is a view schematically showing a state in which the image forming unit housing is supported between side plates, and is a schematic horizontal sectional view along the axis of the photosensitive drum.

13 is a view of one of the bearing means shown in FIG. 12 as viewed from the front after the side plate.

FIG. 14 is a sectional view taken along the line GG of FIG. 13;

FIG. 15 is a view of the other of the bearing means shown in FIG. 12 as viewed from the rear in front of the side plate.

FIG. 16 is a sectional view taken along the line HH of FIG. 15;

17 is a side view of the support mechanism of the transfer roller as viewed from the axial direction of the photosensitive drum (the right side in FIG. 2).

FIG. 18 is a top view of FIG. 17, with the bearing cut away.

FIG. 19 is a sectional view taken along the line II of FIG. 17;

20 is a top view of the image forming unit housing shown in FIG. 1, with an intermediate portion cut away.

21 is a front view of FIG. 20 as viewed from below.

FIG. 22 is a rear view of FIG. 20 as viewed from above.

FIG. 23 is a sectional view taken along the line JJ of FIG. 20;

FIG. 24 is a side view of FIG. 20 as viewed from the right.

FIG. 25 is a sectional view taken along the line KK of FIG. 20;

FIG. 26 is a sectional view taken along line LL of FIG. 20;

FIG. 27 is a sectional view taken along the line MM of FIG. 20;

FIG. 28 is a front view of the bearing member shown in FIG. 6;

FIG. 29 is a top view of FIG. 28;

FIG. 30 is a sectional view taken along the line NN of FIG. 28;

[Explanation of symbols]

 Reference Signs List 2 imaging unit 4 imaging unit housing 6, 8 side wall 10 photoreceptor drum 11 drum main body 12, 14 bearing 16 developing means 17 developing housing 18 cleaning fur brush 20 developing roller 22 transfer roller 30 charger 32 after side plate 34 before side plate 36 , 38 Bearing means 90 Bearing member 100 Support portion 112, 160 Driven gear 170 Shield member 172, 174 End block 173, 175 Supported portion 176 Charging wire 180, 200 Lower bearing member 184 Tension spring member 190, 210 Upper bearing member 220 Holding piece

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 21/00 350

Claims (5)

(57) [Claims] 1. A hollow cylindrical shape having a photosensitive member disposed on an outer peripheral surface thereof.
Photoreceptor drums including the drum body
Between a pair of side wallsRotatableSupported, the photosensitive drum
An imaging element cooperating with the photosensitive drum is provided around
In the arranged image forming apparatus,Hollow cylindrical On the outer peripheral surface at both ends of the drum body
BearingPress fitThe photosensitive drumThe outer peripheral surface ofThe
To each of the side walls via a bearingDirectlySupported, the imaging element being disposed between each of the bearings, The imaging element includes a stationary element and the stationary element
The element includes a charger mounted between each of the side walls;
The charger is spaced from the outer peripheral surface of the photosensitive drum.
A shield extending linearly in the axial direction of the photosensitive drum
Member and end blows provided at both ends of the shield member.
And each of the end blocks includes a shield.
The photoconductor in a direction substantially perpendicular to the direction in which the member extends;
Extends and supports substantially the tangential direction of the outer peripheral surface of the drum
On the upper part radially outward of the outer ring of the bearing
And is detachably supported by the corresponding side wall,  An image forming apparatus comprising: 2. The charging device further includes a charging wire disposed within and extending along the shield member, one end of the charging wire extending within the one of the end blocks. The end of the charging wire is turned at a position substantially extended toward the one extending direction of the end block, and the other end of the charging wire is connected to the shield member within the other of the end block. The image forming apparatus according to claim 1 , wherein the image forming apparatus is changed in direction from an extending direction and is locked at a position substantially extending toward the other extending direction of the end block via a tension spring member. 3. Each of the end blocks is formed with a supported portion projecting from an outer end of the shield member in the extending direction of the shield member. A support portion is provided at an upper portion of the bearing radially outward of the outer ring so as to receive and support the corresponding supported portion so as to be detachable from above, and to support the supported portion of each of the end blocks. corresponding by fitting from above into the support portion, said band collector is supported between each of the side walls, the image forming apparatus according to claim 1. 4. An imaging unit having each of said side walls;
Side plates spaced apart from each other, wherein an axial portion of each of the bearings is disposed to protrude from an outer end of a corresponding one of the side walls, and each of the side plates includes a bearing means. The image forming unit is supported between the side plates by the part of each of the bearings being supported by the corresponding bearing means, and each of the bearing means is provided with the photosensitive member. As viewed in the axial direction of the drum, two points sandwiching a vertical line passing through the axis of the bearing, respectively, in a region below the horizontal line passing through the axis of the bearing on the corresponding outer peripheral surface of the bearing, are respectively point-contacted. A lower bearing member having a pair of support surfaces formed so as to be able to support, and at least one formed in the outer peripheral surface of the bearing and above the horizontal line at least at one point by point contact. One push And an upper bearing member having an upper bearing member, and a retaining piece is detachably mounted on each of the upper bearing members, and each of the upper bearing members is attached to the corresponding side plate. 4. The image forming apparatus according to claim 3 , wherein each of the fixing units is detachably fixed to the image forming unit by pressing the supported portion of the corresponding end block from above. 5. 5. A gap between the outer end of each of the end blocks of the charger and the inner end of the support on each of the corresponding side walls opposite the outer end of the end block. Is formed, and each of the holding pieces is provided between the outer end of each of the end blocks and the inner end of the corresponding support portion in a state where each of the upper bearing members is mounted on the corresponding side plate. The image forming apparatus according to claim 4 , wherein the image forming apparatus is detachably inserted into the gap.