JP2000231231A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device in which each roll of an image carrier unit is not deformed even when the frame of the image forming device main body is deformed. SOLUTION: In the image forming device 1 provided with the image carrier unit with a belt state image carrier so as to be attachable to and detachable from the device main body 14, a 1st supporting part 66 provided with plural 1st bearings 62r and a 2nd supporting part 77 faced to the 1st supporting part 66 through the image carrier unit 40 and provided with one piece of 2nd bearing 62f and arranged. The image carrier unit 40 is provided with plural 1st supporting shafts 60r on one side of the roll that can each be inserted into plural 1st bearings 62r and a 2nd supporting shaft 60f is provided on the other side of the roll that can be inserted to the 2nd bearing 62f. The image carrier unit 40 is positioned to the image forming device main body 14 by intrusion of each 1st supporting shaft 60f into each 1st bearing 62r and the 2nd supporting shaft 60f into the 2nd bearing 62f.

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 electrophotographic copying machine and a laser printer, and more particularly, to an image forming apparatus having an image carrier unit having an image carrier such as a photosensitive member or an intermediate transfer member. It is about.

[0002]

2. Description of the Related Art In an image forming apparatus such as an electrophotographic copying machine, a photoreceptor unit having a photoreceptor on which a toner image is formed, and an intermediate transfer for transferring the toner image on the photoreceptor to a sheet of paper. Some include an intermediate transfer unit having a body. Since these image carrier units need to accurately transfer the toner image onto the paper, they need to be positioned and fixed to the image forming apparatus main body.

[0003] Conventionally, for example, Japanese Patent Laid-Open No. 5-72
As shown in Japanese Patent Application Laid-Open No. 826, two pins (roller shafts) are provided on both sides of a plurality of rolls on which an image carrying belt (photosensitive belt) is stretched. The image bearing unit was positioned and fixed to the image forming apparatus main body by being fitted into two bearings respectively provided on the two side plates.

[0004]

However, the above-mentioned Japanese Patent Application Laid-Open
An image forming apparatus using a positioning technique as disclosed in Japanese Patent Application Laid-Open No. 72826/1995 has the following problems. That is,
The image forming apparatus is not always installed on a flat place, and is often installed on a slightly distorted surface. In such a case, in the related art, since the roll is positioned and fixed by two pins provided on both sides of a plurality of rolls, there is no freedom of each pin, and the above-described rear frame and front frame of the image forming apparatus are not provided. Is distorted, and each roll of the image carrier unit is bent.

If the positional relationship between the rolls deviates from a predetermined position, the image carrying belt stretched on the rolls rotates obliquely with respect to the original rotation direction, causing a so-called belt walk. For this reason, it is difficult to perform accurate transfer to paper. Further, ribs may be provided at both ends of the roll in order to prevent the intermediate transfer belt from coming off the roll due to the belt walk. However, when such a configuration is employed, the belt may come into contact with the rib by belt walking, and the belt may be damaged by friction with the rib.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an image forming apparatus in which each roll of an image carrier unit is not distorted even when a frame of the image forming apparatus main body is distorted.

[0007]

According to a first aspect of the present invention, there is provided an image forming apparatus including an image carrier unit having a belt-shaped image carrier stretched over a plurality of rolls. In an image forming apparatus detachably attached to a main body, a first support having a plurality of first bearings, and a second bearing opposed to the first support with an image carrier unit interposed therebetween And a second support having:
The image carrier unit has, on one side of the roll, a plurality of first support shafts that can respectively enter the plurality of first bearings, and one second support shaft that can enter the second bearing on the other side of the roll. The image carrier unit is positioned with respect to the image forming apparatus main body by the penetration of each first support shaft into each first bearing and the penetration of the second support shaft into the second bearing. .

In the image forming apparatus according to the first aspect of the present invention, when an image carrier unit such as a photoreceptor unit or an intermediate transfer unit is positioned with respect to the main body of the image forming apparatus, the image carrier includes a plurality of through holes, for example. The plurality of first support shafts are respectively made to enter the first bearing, and the second support shaft is made to enter one second bearing. That is, the image carrier unit has a degree of freedom in the movement of the second support portion on which one second bearing is formed. Therefore, even if the image forming apparatus main body is placed on an inclined surface or the like, the frame of the apparatus main body is distorted, and even if the positional relationship between the first support portion and the second support portion is displaced, the force due to the dislocation is Is transmitted only to the first support shaft of the image carrier, and is not transmitted to the second support shaft having a degree of freedom. Thus, it is possible to prevent the image carrier unit from being distorted when the image forming apparatus main body is distorted.

According to a second aspect of the present invention, there is provided an image forming apparatus having an image carrier unit having a belt-shaped image carrier stretched over a plurality of rolls, the image carrier unit being detachably mountable to an image forming apparatus main body. A first support portion having a first support shaft, and a second support portion having one second support shaft while being opposed to the first support portion with the image carrier unit interposed therebetween. The image carrier unit has, on one side of the roll, a plurality of first bearings into which a plurality of first support shafts can enter, and a second bearing into which the second support shaft can enter, on the other side of the roll. Wherein the image carrier unit is positioned with respect to the image forming apparatus main body by the penetration of each first support shaft into each first bearing and the penetration of the second support shaft into the second bearing. I do.

In the image forming apparatus according to the present invention, when positioning an image carrier unit such as a photoreceptor unit or an intermediate transfer unit relative to the image forming apparatus main body, the image carrier unit is formed on the image carrier unit. A plurality of first support shafts respectively penetrate into the plurality of first bearings,
The second support shaft is made to enter one second bearing. That is, the image carrier unit has a degree of freedom in the movement of the second support portion on which one second support shaft is formed. Therefore, even if the image forming apparatus main body is placed on an inclined surface or the like, the frame of the apparatus main body is distorted, and even if the positional relationship between the first support portion and the second support portion is displaced, the force due to the dislocation is Is transmitted only to the first bearing of the image carrier, and is not transmitted to the second bearing having a degree of freedom. Thus, it is possible to prevent the image carrier unit from being distorted when the image forming apparatus main body is distorted.

According to a third aspect of the present invention, in the image forming apparatus according to the first or second aspect, the vertical line of the center of gravity of the image carrier unit is defined by the plurality of first and second support shafts. It intersects with the region where

According to the image forming apparatus of the third aspect, the plurality of first support shafts and the second support shafts allow
The image carrier unit is stably supported.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of an image forming apparatus according to the present invention will be described in detail with reference to the accompanying drawings. Note that the same reference numerals are used for the same elements, and duplicate descriptions are omitted.

FIG. 1 is a schematic configuration diagram showing a color copying machine (image forming apparatus) 1 of the present embodiment. The copying machine 1 mainly includes a copying machine main body 14 and an automatic document feeder 18 that opens and closes a copy glass 16 installed on an upper surface of the copying machine main body 14.

A document reading unit 20 for opening the automatic document feeder 18 to read an image of a fixed document placed on the copy glass 16 and converting the image into an electric image signal is provided inside the copying machine body 14. Image forming unit 22 that forms a visible image on a sheet based on the image signal received from document reading unit 20
And a plurality of paper feed trays 34 for supplying paper to the image forming unit 22 are provided.

The document reading section 20 includes a CCD housed therein.
After reading the color image information of the original as analog signals of R (red), G (green), and B (blue),
Based on the signal, K (black), Y (yellow), M
(Magenta) and C (cyan) color image data are generated.

Next, the outline of the image forming section 22 will be described.
The image forming unit 22 mainly includes an exposure device 24 that outputs a laser beam modulated based on color image data from the document reading unit 20, and a photosensitive device that is charged by a charging roll 26 and is exposed by the laser beam. Body drum 28
And a rotary developing device 3 for developing the electrostatic latent image formed on the photosensitive drum 28 by this exposure into a toner image.
0, an intermediate transfer unit (image carrier unit) 40 including an intermediate transfer belt 32 on which a toner image formed on the photosensitive drum 28 is primarily transferred at a primary transfer position T ₁ ;
An intermediate transfer belt 32 to the secondary transfer unit 50 for transferring the secondary at a secondary transfer position T ₂ on the supplied paper and primarily transferred toner image from the paper feed tray 34, the unfixed secondarily transferred to the paper Fixing device 3 for fixing the toner image on the paper
6 is comprised.

The developing device 30 includes developing devices 30 _K and 3 of four colors of K, Y, M and C mounted around the rotation shaft 30o.
0 _Y , 30 _M , and 30 _{C so} that the developing units 30 _K , 30 _Y , 30 _M , and 30 _C for each of the four colors sequentially face the photosensitive drum 28 as the rotation shaft 30o rotates. It is configured. The developing devices _{30 K, 30 Y, 30 M} , 30 C develops the electrostatic latent image formed on the photosensitive drum 28 K, Y, M, the toner image of each color of C.

The intermediate transfer belt 32 of the intermediate transfer unit 40, primary transfer roll 36 disposed in the primary transfer position T _1, the driving roller 38, tension roller 42, a steering roll 44, the inner secondary transfer roller (bias roll ) 46 and the like, and a drive mechanism 38 (not shown) drives the drive roll 38 at substantially the same speed as the photosensitive drum 28.
And rotates in the direction of the arrow in FIG. The intermediate transfer unit 40 is detachable from the copier body 14.

The secondary transfer unit 50 has a secondary transfer position T
₁ includes an outer secondary transfer roll 48 disposed at the first position. The outer secondary transfer roll 48 is used for the intermediate transfer belt 3.
The second secondary transfer roller 46 is opposed to the inner secondary transfer roll 46 with 2 interposed therebetween, and is pressed toward the inner secondary transfer roll 46 when performing the secondary transfer. Then, when a bias voltage having a polarity opposite to that of the toner is applied to the inner secondary transfer roll 46, the toner image on the intermediate transfer belt 32 is secondarily transferred to the sheet. After the toner image is transferred to the sheet, the toner image is fixed by the fixing device 36, and then the copying machine 1
4 to the outside. The above is the description of the copying machine 1 of the present embodiment.
It is an outline of.

Next, the intermediate transfer unit 40, which is a feature of the copying machine 1 of the present embodiment, will be described in detail with reference to FIGS.

FIG. 2 is a perspective view showing a state in which the intermediate transfer body unit 40 is pulled out from the copying machine main body 14. The intermediate transfer body unit 40 includes a front board 54 and a rear board 56 that support various rolls that stretch the intermediate transfer belt 32 such as the drive roll 38 and the primary transfer roll 36 on both sides. The front board 54 is provided with a connecting member 58 having a U-shaped cross section and a positioning front pin (second support shaft) 60f, which is connected to a handle described later, on the opposite side of the copying machine main body 14, that is, on the surface on the side where the front board 54 is pulled out. Have been. On the other hand, two rear pins (first support shafts) 60 for positioning are provided on the rear surface of the rear board 56 in the drawing.
r are provided at predetermined intervals. The front pins 60f and the rear pins 60r have tapered tips.

The intermediate transfer unit 40 is configured such that the vertical line L of the center of gravity G of the intermediate transfer unit 40 passes through a triangular region R defined by the two rear pins 60r and the front pins 60f. ing.

Next, a description will be given of a unit moving / holding mechanism 64 for moving the intermediate transfer body unit 40 to a state where it can be attached to and detached from the copying machine main body 14 and to a state where the primary transfer can be carried out. The unit movement holding mechanism 64
Fixing plate (first support) 6 fixed to copying machine body 14
6, two rail guides 68 fixed to the fixed plate 66 and the copying machine main body 14, and a slide support slidable with respect to the rail guides 68 and capable of supporting the intermediate transfer body unit 40. And a unit 70.

Two through holes (first bearings) 62r are formed in the fixing plate 66 at a predetermined interval. The inner diameter of the through hole 62r is larger than the diameter of the rear pin 60r, and is configured so that the rear pin 60r can be inserted.

A guide groove 72 is formed in each rail guide 68, and the respective guide grooves 72 are arranged so as to face each other. Further, the slide support portion 70 includes two rails 74 that slide in the guide grooves 72 in the direction of the arrow in the figure, and a front plate (second support portion) 77 that supports each rail 74. . Further, each rail 74 is provided with a substantially rectangular support plate 76 capable of supporting the intermediate transfer body unit 40, and the front plate 77 is used when the slide support portion 70 is pulled out of the copying machine body 14. A handle 78 and a substantially rectangular support plate 76 capable of supporting the intermediate transfer body unit 40 are provided, and one through hole (second bearing) 62f is formed. The inner diameter of the through hole 62f is larger than the diameter of the front pin 60f, and is configured so that the front pin 60f can be inserted. A front plate 77 is connected to the handle 78 on the side of the copier body 14 and the intermediate transfer body unit 40 is connected to the handle 78.
Is provided with a connection mechanism 80 that can be connected to the connection member 58 provided in the first embodiment. The coupling mechanism 80 has a U-shaped groove that can be fitted to the coupling member 58.

The above is the structure of the unit moving and holding mechanism 64. When the intermediate transfer unit 40 is accommodated in the copying machine main body 14, the slide support is carried out after the intermediate transfer unit 40 is mounted on the three support plates 76. The part 70 is slid toward the inside of the main body. Then, as the slide support 70 slides, the front pin 60f and the rear pins 60r, 60r
The tapered distal end of r slides through the inner edges of the through-hole 62f and the through-holes 62r, 62r to enter the holes, and the connecting member 58 and the connecting mechanism 80 of the handle 78 start to be connected. When the front plate 77 cannot be pressed any further and is in a fixed state, the intermediate transfer body unit 40 is housed in a state capable of transferring.

FIG. 3 shows that the front plate 77 is pushed to a fixed state,
FIG. 4 is a plan view showing a state where the intermediate transfer body unit 40 is housed in the copying machine main body 14. In this state, the intermediate transfer body unit 40 includes the two through holes 62r and 62
r and the front pins 60f passing through the through holes 62f of the front plate 77, are positioned with respect to the copying machine main body 14 and the slide support portion 70, and the bottom surface of the intermediate transfer body unit 40 is , Are separated from the upper surface of the support plate 76 of the slide support portion 70.

The intermediate transfer body unit 40 has a degree of freedom in the movement of the front plate 77 in which one through hole 62f is formed. For this reason, the frame of the copying machine main body 14 is distorted when the copying machine main body 14 is mounted on an inclined surface or the like, and the fixing plate 66 fixed to the copying machine main body 14 and the front plate 77 of the slide support portion 70. Is displaced, the force due to this displacement is transmitted only to the rear pins 60r, 60r of the intermediate transfer body unit 40, and is not transmitted to the front pin 60f having a degree of freedom. Thus, even if the frame of the copying machine main body 14 is distorted, it is possible to prevent the intermediate transfer body unit 40 from being distorted, and to prevent the rotation direction of the intermediate transfer belt 32 from being inclined.

Since the rear side of the intermediate transfer unit 40 is supported by the two rear pins 60r, 60r, the intermediate transfer unit 40 is stably supported. Furthermore, the intermediate transfer body unit 40 of the present embodiment
Is configured such that the vertical line L of the center of gravity G of the intermediate transfer body unit 40 passes through a triangular region R defined by the two rear pins 60r and the front pins 60f, so that the inclination of the intermediate transfer body unit 40 Can be prevented and can be stably supported.

In this embodiment, the front pins 60
f and the rear pins 60r, 6
The distance X between the ring support 61r and the ring support 61r does not accommodate the intermediate transfer body unit 40.
It is configured to be longer than the distance between the fixed plate 66 and the front plate 77 when 0 is pushed all the way in. For this reason,
Intermediate transfer unit 4 with fixed plate 66 and front plate 77
The holding power of 0 is increased.

As described above, the invention made by the inventor has been specifically described based on the embodiments. However, the present invention is not limited to the above embodiments. For example, the present invention can be applied to a photoconductor unit in addition to the intermediate transfer unit. Further, a bearing such as a through hole is formed in the image carrier unit, and a support shaft (pin) that can be inserted into the bearing in the first support portion (fixed plate) and the second support portion (front plate).
May be provided.

The number of rear pins (first support shafts) is not limited to two, but may be three or more. Further, the number of front pins may be plural and the number of rear pins may be one. Further, the first bearing and the second bearing are not limited to the through-holes, and may be grooves having a bottom, or semi-circular cutouts on which the image carrier unit can be mounted from above.

[0034]

As described above, according to the present invention,
When positioning an image carrier unit such as a photoreceptor unit or an intermediate transfer unit with respect to the image forming apparatus main body, while injecting a plurality of first support shafts into a first bearing composed of a plurality of through holes, for example, The second support shaft is made to enter one second bearing. That is, the image carrier unit has a degree of freedom in the movement of the second support portion on which one second bearing is formed. Therefore, even if the image forming apparatus main body is placed on an inclined surface or the like, the frame of the apparatus main body is distorted, and even if the positional relationship between the first support portion and the second support portion is displaced, the force due to the dislocation is Is transmitted only to the first support shaft of the image carrier, and is not transmitted to the second support shaft having a degree of freedom. Thus, it is possible to prevent the image carrier unit from being distorted when the image forming apparatus main body is distorted.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a color copying machine of the present invention.

FIG. 2 is a perspective view showing a state in which an intermediate transfer body unit of the present invention is pulled out from a copying machine main body.

FIG. 3 is a plan view showing a state in which the intermediate transfer unit is accommodated in a copying machine main body.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Copy machine (image forming apparatus), 14 ... Copy machine main body, 20
... Document reading section, 22. Image forming section, 24. Exposure device, 2
Reference numeral 6: charging roll, 28: photosensitive drum, 30: developing device, 32: intermediate transfer belt (intermediate transfer member), 36: primary transfer roll, 36: fixing device, 38: drive roll, 40
... Intermediate transfer unit, 46 ... Inner secondary transfer roll, 4
8 outer secondary transfer roll, 50 secondary transfer unit, 5
4: Front board, 56: Rear board, 58: Connection member, 60f: Front pin (second support shaft), 62f: Through hole (second bearing), 60r: Rear pin (first support shaft), 62r: Through hole ( A first bearing), 64 unit moving / holding mechanism, 66 fixed plate (first support), 70
Slide support, 76: support plate, 77: front plate (second support), 78: handle, 80: coupling mechanism.

Continuing from the front page (72) Inventor Satoshi Fukada 2274 Hongo, Ebina-shi, Kanagawa Prefecture Fuji Xerox Co., Ltd. Ebina Works F-term (reference) 2H035 CA05 CA07 CB06 CD01 CD05 CD09 CD11 CD14 2H071 BA03 BA13 BA16 BA19 BA22 BA36 DA09 DA15

Claims (3)

[Claims] 1. An image forming apparatus having an image carrier unit having a belt-shaped image carrier stretched over a plurality of rolls, the image carrier having a plurality of first bearings. A first support portion, and a second support portion having one second bearing, facing the first support portion with the image carrier unit interposed therebetween, Has a plurality of first support shafts that can respectively enter the plurality of first bearings on one side of the roll, and one second support shaft that can enter the second bearings on the other side of the roll. The image carrier unit is positioned with respect to the image forming apparatus main body by intrusion of the first support shaft into the first bearing and intrusion of the second support shaft into the second bearing. Image forming characterized by the fact that Location. 2. An image forming apparatus having an image carrier unit having a belt-shaped image carrier stretched over a plurality of rolls, which is detachably mountable to an image forming apparatus main body. A first support portion having a second support portion having one second support shaft while facing the first support portion with the image carrier unit interposed therebetween. The body unit has, on one side of the roll, a plurality of first bearings into which the plurality of first support shafts can enter, and a second bearing into which the second support shaft can enter, other than the roll. The image carrier unit with respect to the image forming apparatus main body due to intrusion of each of the first support shafts into each of the first bearings and intrusion of the second support shafts into the second bearings. Image formation characterized by being positioned Location. 3. The image forming apparatus according to claim 1, wherein a vertical line of a center of gravity of the image carrier unit intersects a region defined by the plurality of first support shafts and the second support shaft. Image forming apparatus.