JP3252600B2 - 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 having a plurality of photoreceptors and transferring toner images of different colors formed on the respective photoreceptors in a superimposed manner onto a transfer sheet conveyed in contact with the photoreceptors. More particularly, the present invention relates to an image forming apparatus having a photosensitive member positioning mechanism with respect to an apparatus main body.

[0002]

2. Description of the Related Art An overall configuration of a color image forming apparatus will be described with reference to FIG. A color image forming apparatus that superimposes toner images of different colors on a sheet is transferred to a document reading unit 10, an image processing unit 20 that electrically processes a signal of the read color image information, and an image processing unit 20. Image formation for transferring a toner image onto transfer paper based on a development signal for developing each color of black (K), cyan (C), magenta (M), and yellow (Y) And a unit 30. In the document reading unit 10, a document placed on the contact glass 11 is illuminated by the illumination system 12, color-separated and read by the optical system 13, and output as a digital signal to the image processing unit 20. The image processing unit 20 converts each signal into a development signal of each color of black, yellow, magenta, and cyan, and the photoconductors 31K, 31Y, and 31 of the image forming unit 30.
M and 31C are output as image forming signals. Each photoconductor 31 has a charger 35, a developing device 36, a transfer device 37
The toner image formed on each photoreceptor 31 by a known electrostatic photographic process by these recording devices 32 is superimposed at the timing by the operation of the transfer device 37. Transfer belt 33
The image is transferred as a color image on a transfer sheet conveyed upward.

After the transfer, the transfer sheet is separated from the transfer belt 33 and fixed by a fixing device 38, and the sheet on which a full-color image is formed is discharged out of the apparatus by discharge rollers 39. In this manner, a plurality of photoconductors are arranged in parallel, and a color image forming apparatus of this kind that forms a correct color by sequentially superimposing toner images of respective colors formed on the photoconductors on transfer paper. However, when the transfer position of each image is shifted, problems such as color reproduction failure and color shift occur. Therefore, in order to prevent the displacement of a plurality of color images in the parallel direction, it is necessary to maintain the interval between the photoconductors and maintain the positional accuracy, and the shaft of each photoconductor is accurately supported by the rear plate and the front plate of the apparatus main body. It has a configuration that In this type of image forming apparatus, at least one of the side plates for positioning the photosensitive member shaft is detachable for maintenance or the like.

For example, in Japanese Utility Model Laid-Open No. 2-89447, one end of the shaft of each photoconductor is supported by a rear plate of the apparatus main body.
There is disclosed a configuration in which the other end of the shaft is supported by a support (face plate) detachably attached to the front side plate, thereby accurately maintaining the parallelism of the photoconductor. This configuration will be described with reference to FIG. The mounting holes 47 of the face plate 45 are fitted into positioning pins 42 provided on the left and right of the front side plate 40 of the apparatus main body, and the face plate 45 is first positioned. When the face plate 45 is further inserted into the apparatus main body along the positioning pins 42, the photoconductor shafts 310Y, 310M, and 310C are supported by the rear plate in a cantilever state and have an appropriate chamfered portion at the end. 310C,
The free end of 310B is naturally inserted into the corresponding bearing 46, and the photoconductor is positioned.

[0005]

However, in the disclosed method of positioning the photosensitive member shaft, the photosensitive member shaft 31 is not provided.
5 and the bearing 46, and between the positioning pins 42 and the mounting hole 47, tolerances fitting are very strict fitting portion occurs. Therefore, if the face plate 45 is inclined with respect to the front plate 40, galling occurs between the photoconductor shaft 315 and the bearing 46, and between the positioning pin 42 and the mounting hole 47 (see FIG. 8). For this reason, a problem that a large operating force is required when attaching and detaching the face plate 45 to and from the front side plate 40, and
There is an inconvenience that the positional accuracy of the photoconductor is deteriorated due to galling when the face plate 45 is attached or detached.

Therefore, the present invention improves the maintainability by reducing the operating force when attaching and detaching a support plate (face plate) that supports one end of the photosensitive member which is detachable from the apparatus main body and has high positioning accuracy of the photosensitive member. It is another object of the present invention to provide an image forming apparatus having a photosensitive member positioning mechanism that prevents deterioration in accuracy due to galling at the time of attachment and detachment.

[0007]

An image forming apparatus according to the present invention has a bearing hole for a support shaft of a photosensitive member supported in a cantilever state in the apparatus main body, and is fixed to the image forming apparatus main body. A positioning pin is formed in one of the image forming apparatus main body and the support, and a positioning hole into which the positioning pin is inserted is formed in the other, and a fitting portion between the positioning pin and the positioning hole is substantially in line contact. Is provided as a basic configuration.

Further, the fitting portion between the bearing hole of the support and the support shaft of the photoreceptor is substantially in linear contact, or the outer periphery of a portion corresponding to the fitting portion of the positioning hole of the support of the positioning pin is formed. A configuration having a curved surface structure, a configuration in which the outer periphery of a portion corresponding to a fitting portion of a bearing hole of a support of a photoreceptor support shaft has a curved surface structure, and a bearing hole and / or a positioning hole of a support projecting into the hole. A curved surface configuration is provided.

[0009]

When the support is attached to or detached from the main body of the image forming apparatus, the contact between the support shaft of the photoreceptor and the bearing hole or between the positioning pin and the positioning hole is in linear contact, so that the contact area is large. It can be easily operated without galling as compared with.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. Embodiment 1 FIG. 1 is a perspective view of a state in which a support 200 has been removed from an apparatus main body 100. The apparatus main body 100 has a photoconductor 120K,
A window 140 for exposing 120Y, 120M, and 120C is formed.
50 and 152 are provided. Positioning pins 150, 1
52 is fixed to the apparatus main body 100 by a stopper 160. The other end of each photoconductor 120 is fixed to another side plate of the apparatus main body (not shown).

The window 20 of the apparatus body 100 has a support 20
0 is attached. The support 200 is provided at least in the apparatus main body 10.
The bearing body 210 is a plate having a size enough to cover the window 140, and has a perforated bearing hole 210 for fitting and supporting the shaft 130 of each photoconductor 120 (K, Y, M, C). Each bearing hole 210
Are arranged at intervals equal to the intervals at which the photoconductors 120 are arranged, and the positional accuracy is maintained. The support 200 has holes (positioning holes) 25 into which the positioning pins 150 and 155 are inserted at positions corresponding to the positioning pins 150 and 155.
0 and 255 are provided. Further, a handle 23 for facilitating the handling of the support plate at the time of attachment and detachment is provided on the surface of the support 200.
0 is fixed. Further, a positioning plate 260 for positioning with a transfer module portion provided below the apparatus main body 100 is provided at a lower end edge of the support 200. In order to attach the support 200 thus configured to the apparatus main body 100, first, the positioning holes 250 of the support 200,
255 to the positioning pins 150, 155 of the apparatus body 100.
Position the positioning pin 150 to the positioning hole 25.
0, the positioning pins 155 are inserted into the positioning holes 255, respectively. With this operation, the axis 1 of each photoconductor 120
30 fits into the bearing hole 210 of the support 200, while the shaft 130 fits into the bearing hole 210. At this time, the positioning pins 150 and 155 of the present invention have a curved surface on the outer periphery.

FIG. 2 is an enlarged view of a fitting portion between the positioning pin and the positioning hole. Stopper 1 on device body 100
The positioning pin 150 fixed by the support member 60 fits into the positioning hole 250 of the support 200 and
Is fixed to the apparatus main body 100. Positioning pin 15
Numeral 0 designates the fitting portion 153 with the positioning hole 250 as a curved surface structure having a curvature in the mounting axis direction. Positioning pin 15
The curved surface of 0,155 has a convex shape facing outward, and the portion having the largest curvature is almost w / from the base of the pins 150, 155 when the thickness of the support 200 is w.
A position of 2 is appropriate. The positioning pin 150 is the support 2
In the fitting portion with the portion 00, a line contact is made at the portion having the largest curvature, that is, substantially at the center of the fitting portion.

Since the fitting portion of the positioning pin 150 with the support 200 has a curved surface structure, the positioning pin 150
Is inserted into the hole 250 of the support 200, the contact friction between the inner wall surface of the positioning hole 250 and the positioning pin 150 is small, and the insertion and removal of the positioning pin 150 can be easily performed. Further, as shown in FIG. 3, even if the support 200 is disposed obliquely with respect to the apparatus main body 100, the contact surface between the positioning hole 250 and the positioning pin 150 is small.
The support plate 200 is easily pressed in the direction of the arrow on the main body 100 side without the occurrence of galling, or
It is easily corrected by pulling with zero. Further, a fitting portion 133 with the bearing hole 210 of the support 200 is formed at the tip of the shaft 130 of each photoconductor 120. The fitting portion 133 has a curved surface structure having a curvature in the mounting axis direction. The curved surface of the fitting portion 133 of the mounting shaft 130 has a convex shape facing outward, and the portion having the largest curvature is defined by the fitting portion 133.
Of the bearing hole 2 at the portion having the largest curvature, that is, substantially at the center of the fitting portion.
The fitting portion 133 between the shaft 10 and the shaft 10 makes line contact.

As described above, the photosensitive member shaft 130 and the support 20
By making a line contact with 0, attachment and detachment of the photoconductor 120 to and from the support 200 are facilitated. In this embodiment, the positioning pins are provided on the image forming apparatus main body side and the positioning holes are formed on the support side. However, the positioning holes are provided on the image forming apparatus main body side and the positioning pins are provided on the support side. The same operation and effect can be obtained.

Embodiment 2 In this embodiment, an example is shown in which the wall surface of the positioning hole of the support 200 has a curved surface structure (see FIG. 5). Support 20
A pin receiving portion 280 is provided in the hole 260 drilled at zero.
The pin receiving portion 280 has a curved wall structure by protruding the wall surface of the hole into the inside of the hole to form a fitting portion 288. The positioning pin 180 is inserted into the pin receiving portion 280 of the support 200 configured as described above. Even if the positioning pin 180 is a columnar pin, the contact of the fitting portion 288 with the positioning pin 180 is a line contact. In the attachment and detachment of the apparatus main body 100 and the support 200 according to this embodiment, since the fitting portion has a curved surface, no galling occurs between the positioning pin 180 and the support 200. Further, the support 2
As shown in Example 1, the wall surface of the bearing hole of No. 00 has a curved surface structure protruding inward of the hole, so that the positioning pin and the photoreceptor shaft are in line contact with the bearing hole and the positioning hole, so that no galling occurs. The operation of attaching and detaching the photoconductor to and from the support 200 is facilitated.

[0016]

According to the image forming apparatus of the present invention, the operation force required for detaching and supporting the support for positioning the photoreceptor shaft can be reduced, and an apparatus having improved maintainability can be economically provided. Further, it is possible to prevent deterioration of the positional accuracy of the photoconductor due to galling when the support for positioning the photoconductor shaft is detached, and to maintain stable image formation with high positional accuracy.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of a support mounting portion.

FIG. 2 is a sectional view of a mounting portion of a positioning pin.

FIG. 3 is an explanatory diagram of a state of a positioning portion of a support.

FIG. 4 is an explanatory diagram of a positioning portion in a state where a support shaft of the photoconductor has a curved surface structure.

FIG. 5 is a sectional view of a mounting portion of a positioning pin in which a positioning hole on a support body has a curved surface structure.

FIG. 6 is an overall explanatory diagram of the image forming apparatus.

FIG. 7 is a configuration explanatory view of a positioning portion of a support in a conventional example.

FIG. 8 is an explanatory view of a state of a positioning portion of a support in a conventional example.

[Explanation of symbols]

Reference Signs List 100 image forming apparatus main body, 120 photoconductor, 13
0 Photoconductor support shaft, 150, 155 positioning pin,
153 fitting part, 200 support, 210 bearing hole, 250, 255 positioning hole.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 13/01 G03G 15/01-15/01 117 G03G 15/00 550 G03G 21/00 350 G03G 21/16

Claims (5)

(57) [Claims] [Claim 1, further comprising an image forming apparatus main body, a plurality of bearing holes, and a support member fixed to the image forming apparatus main body, double having a support shaft which is inserted into the bearing hole on at least one end
Number of photoconductors, and a positioning pin is formed in one of the image forming apparatus main body and the support, and a positioning hole is formed in the other of the positioning pin . Corresponds to the mating part
As a curved surface structure that becomes convex toward the outer periphery of the part
An image forming apparatus characterized by comprising substantially by linear contact of the engaging portion of the positioning pin and the positioning hole. 2. The support shaft of a plurality of photosensitive members.
The outer periphery of the part corresponding to the fitting part of the receiving hole is convex outward.
The support shaft of the photoreceptor and the support
It becomes substantially by linear contact of the fitting portion of the bearing bore claim 1
The image forming apparatus as described in the above. 3. An image forming apparatus having a main body and a plurality of bearing holes.
A support fixed to the image forming apparatus main body;
At least one end has a support shaft inserted into the bearing hole.
Number of photoconductors, and is located at one of the image forming apparatus main body and the support.
Positioning pin into the other end where the positioning pin is inserted.
The positioning hole is formed as a curved surface structure protruding inside the hole.
Substantially linear contact between the positioning hole and the fitting portion of the positioning pin
An image forming apparatus characterized by being touched . 4. An image forming apparatus having a main body and a plurality of bearing holes.
A support fixed to the image forming apparatus main body;
At least one end has a support shaft inserted into the bearing hole.
Number of photoconductors, and is located at one of the image forming apparatus main body and the support.
Positioning pin into the other end where the positioning pin is inserted.
To form a fit hole, a song <br/> surface structure to be convex toward the outer periphery of the portion corresponding to the fitting portion of the bearing hole of the support outwardly of the support shaft of the plurality of photosensitive members The support shaft and the fitting portion between the bearing hole are substantially
An image forming apparatus characterized by being brought into line contact with an image forming apparatus. 5. An image forming apparatus having a main body and a plurality of bearing holes.
And a support fixed to the image forming instrumentation Okimoto body, small
At least one end has a support shaft inserted into the bearing hole.
Number of photoconductors, and is located at one of the image forming apparatus main body and the support.
Positioning pin into the other end where the positioning pin is inserted.
A curved surface structure in which holes are formed and a plurality of bearing holes of the support are projected inside the holes.
The fitting portion between the bearing hole and the support shaft of the photoreceptor is substantially
An image forming apparatus characterized by being brought into linear contact .