JP2001305828A - Color image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a long-life color image forming device without causing a damage or a break of an intermediate transfer belt. SOLUTION: The color image forming device is constituted to have plural image forming units arranged in tandem type, an endless intermediate transfer belt 46' that transfers a color image in one lump, which is formed by transferring seriatim each color's toner image developed on a photoreceptor 51a of the image forming unit with going round along the direction of the arrangement of the image forming unit, to a sheet material, a belt cleaning unit which is arranged in contact with the intermediate transfer belt 46' to clean the surface of the intermediate transfer belt 46', and larger width B of the photosensitive unit 51a than that of the intermediate transfer belt 46'A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus for forming a composite image by superimposing image information using electrophotographic technology or the like.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus employing an electrophotographic technique, a photosensitive member as an image carrier is charged by a charger, and the photosensitive member is irradiated with light according to image information to form a latent image. Is formed, and the latent image is developed by a developing roller, and the visualized toner image is transferred to a sheet material or the like to form an image.

On the other hand, a plurality of photosensitive members on which such a series of image forming processes are developed in accordance with colorization of an image are provided, and each color image of a cyan image, a magenta image, a yellow image, and preferably a black image is formed. Formed on each photoconductor,
Many tandem-type color image forming apparatuses that form a full-color image by superimposing and transferring each color image on a sheet material at a transfer position of each photoconductor have been proposed.

[0004] Such a tandem type color image forming apparatus has an image forming section for each color, and is considered to be advantageous for speeding up.

FIG. 2 is a schematic sectional view of a tandem type color image forming apparatus, FIG. 3 is a schematic sectional view of an image forming unit in the color image forming apparatus, and FIG. 4 is a sectional view of a cleaning unit in the color image forming apparatus. FIG. 5A is a schematic cross-sectional view of a photoconductor in the color image forming apparatus, FIG. 5B is a schematic configuration diagram of a photoconductor sheet in the color image forming apparatus, and FIG. FIG. 3 is a schematic diagram of a photosensitive member width and an intermediate transfer belt width in the apparatus.

As shown in FIG. 2, a color image forming apparatus includes an image forming unit 51 for forming toner images of yellow (Y), magenta (M), cyan (C), and black (K), respectively. 52, 53, and 54; an exposure device 55 for outputting an image signal to form an electrostatic latent image;
An intermediate transfer belt unit 40 in which the closed loop of the intermediate transfer belt 46 is in contact with the image forming units 51, 52, 53, 54; a cleaning unit 60 for cleaning the intermediate transfer belt 46; a transfer roller 59; A unit 57 and a sheet cassette 58 for supplying sheets P stacked and stored are provided.

The yellow (Y) image forming unit 5
Reference numeral 1 denotes a photoconductor 51 on which an electrostatic latent image is formed on the peripheral surface by a laser beam from an exposure device 55 as shown in FIG.
a, a charger 51e for charging the same, and a photoconductor 51a
And a cleaner 51g for removing residual toner on the photoconductor after transferring the toner image to the intermediate transfer belt 46. The other image forming units 52 to 54 have the same configuration.

As shown in FIG. 4, the cleaning unit 60 includes a cleaning brush 61 for collecting toner from the intermediate transfer belt 46, a collection roller 62 for adsorbing toner adhered to the cleaning brush 61, and a toner on the collection roller 62. Blade 63 for scraping off toner, and screw 6 for transporting toner to a waste toner box (not shown)
And 4.

As shown in FIG. 5A, the photoreceptor 51a has a photoreceptor ground layer 51c on a photoreceptor base 51b, and a photoreceptor photoreceptor layer 51d is provided thereon.
Here, the photoconductor base 51b and the photoconductor ground layer 51c are used.
Are formed of the same aluminum drum. FIG.
When a sheet is used as the photoreceptor 51 'as shown in (b), the base 51b' and the ground layer 51c 'may be made of different materials, but the ground layer 51c' is used to obtain good electrical conduction. It is formed of a metal such as aluminum or a nickel alloy.

[0010] The intermediate transfer belt unit 40 is shown in FIG.
The intermediate transfer belt 46 is disposed in a closed loop shape and has reinforcing members 3 attached to both ends to prevent the occurrence of cracks and breakage (see FIG. 6), a driving roller 41a for driving the belt to travel, and a transfer. It comprises a facing roller 41b and a tension roller 41c for applying tension to the intermediate transfer belt 46 by a spring member (not shown). As shown in FIG. 6, the width A ′ of the intermediate transfer belt is larger than the width B ′ of the photoconductor.

As shown in FIG. 1, the fixing unit 57 includes a heating roller 57a for heating the toner and a pressure roller 57b for sandwiching the sheet.

In the color image forming apparatus having such a configuration, for example, first, a yellow image forming unit 51 is provided.
A latent image of the yellow component color of the image information is formed by the exposure device 55 on the photosensitive member 51a. This latent image is visualized as a yellow toner image by the developing roller 51f, and is transferred onto the intermediate transfer belt 46. During this time, a latent image of the magenta component color is formed, and the magenta toner image of the magenta toner is visualized by the developing device 52. Then, the magenta toner image is transferred to the intermediate transfer belt 46 on which the transfer of the yellow toner image has been completed, and is superimposed on the yellow toner image. Thereafter, image formation is performed in the same manner for the cyan toner image and the black toner image, and the superposition of the four color toner images on the intermediate transfer belt 46 is completed. Then, after the toner image on the intermediate transfer belt 46 is transferred to the sheet P conveyed from the sheet cassette 58 by the transfer roller 59, the sheet P passes through the fixing unit 57, where the toner is fixed and the sheet P is discharged. .

The residual toner on the photosensitive member 51a, which has been transferred to the intermediate transfer belt 46, is removed by a cleaner 51g. The residual toner on the intermediate transfer belt 46, which has been transferred to the paper P, is cleaned by a cleaning member, here, a cleaning brush 61 to which a bias is applied, and the collected toner is attracted to a collection roller 62 and is screwed by a blade 63. It is dropped to 64 parts. Thereafter, the toner is conveyed by a screw 64 to a waste toner box (not shown).

[0014]

However, in the configuration of the conventional color image forming apparatus, the image forming unit 5
1, the toner is leaked from the end of the developing roller 51f, the dropped toner is received by the intermediate transfer belt 46, transported to the cleaning unit, and collected by the cleaning unit 60. It was necessary to be larger than the width B. Therefore, the end edge of the photoconductor 51 a comes into contact with the intermediate transfer belt 46.
In the photoconductor 51a, the photoconductor ground layer 51c is made of a metal such as aluminum.
Pressing occurs between the intermediate transfer belt 46 and the intermediate transfer belt 46. The intermediate transfer belt 46 and the photosensitive member 5 are caused by the variation in the diameter of the driving roller 41a and the variation in the diameter of the photosensitive member 51a.
Since a peripheral speed difference occurs between 1a, the intermediate transfer belt 46 is rubbed with the metal edge. Therefore, the intermediate transfer belt 46 may be damaged or cut during the life of the intermediate transfer belt 46.

An object of the present invention is to provide a color image forming apparatus having a long service life without causing friction between an edge of a photosensitive member and an intermediate transfer belt in an image forming unit.

[0016]

According to the present invention, a plurality of image forming units are arranged in tandem, and toner images of respective colors developed on a photoreceptor in the image forming units are sequentially arranged. Belt cleaning for providing an intermediate transfer belt unit for collectively transferring a color image formed by transfer to a sheet material so that the intermediate transfer belt unit runs around in the arrangement direction of the image forming units and cleans the intermediate transfer belt unit A color image forming apparatus including a unit and a width of the intermediate transfer belt being smaller than a width of the photoconductor.

According to the present invention, it is possible to provide a long-life color image forming apparatus without breaking and cutting the intermediate transfer belt.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention forms a tandem type developing roller for forming an electrostatic latent image on a photoreceptor by an exposure means and developing with a plurality of color toners. A plurality of arranged image forming units and a color image formed by successively transferring toner images of each color developed on a photoreceptor by traveling around in the arrangement direction of the image forming units are collectively transferred to a sheet material. In a color image forming apparatus including an endless intermediate transfer belt unit and a belt cleaning unit that is disposed in contact with the intermediate transfer belt unit and cleans the intermediate transfer belt unit, the width of the photoconductor is larger than the width of the intermediate transfer belt. Is a large-sized color image forming apparatus, and it is possible to provide a long-life color image forming apparatus without breaking and cutting the intermediate transfer belt. It has the effect of say.

According to a second aspect of the present invention, there is provided the color image forming apparatus according to the first aspect, wherein the photosensitive member is a photosensitive drum, and has a long life without breaking the intermediate transfer belt. This has the effect that a color image forming apparatus can be provided.

According to a third aspect of the present invention, in the color image forming apparatus according to the first aspect, the photosensitive member is a photosensitive belt, and a long service life without breakage of the intermediate transfer belt is achieved. This has the effect that a color image forming apparatus can be provided.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1) FIG. 1 is a schematic diagram showing the relationship between the width of a photosensitive member and the width of an intermediate transfer belt in an image forming unit of a color image forming apparatus according to Embodiment 1 of the present invention.

The color image forming apparatus according to the first embodiment of the present invention has the same configuration as that of the above-described conventional technology except for the relation between the edge of the photosensitive member and the intermediate transfer belt in the image forming unit.

That is, as shown in FIG. 2, image forming units 51, 52, 53 for forming toner images of yellow (Y), magenta (M), cyan (C) and black (K), respectively. 54, an exposure device 55 for outputting an image signal to form an electrostatic latent image, an intermediate transfer belt unit 40, a cleaning unit 60 for cleaning the intermediate transfer belt, and a transfer roller 59.
, A fixing unit 57, and a paper cassette 58 for supplying the stacked paper P.

As shown in FIG. 3, the yellow (Y) image forming unit 51 includes a photosensitive member 51a and a charger 51.
e, a developing roller 51f, and a cleaner 51g, and the other image forming units 52 to 54 have the same configuration.

As shown in FIG. 3, the yellow (Y) image forming unit 51 includes a photosensitive member 51a and a charger 51.
e, a developing roller 51f, and a cleaner 51g, and the other image forming units 52 to 54 have the same configuration. The photoconductor 51a may be a photoconductor belt.

Further, the cleaning unit 60 is provided as shown in FIG.
As shown in FIG.
2, a blade 63, and a screw 64.

The photosensitive member 51a includes a photosensitive member base 51b, a photosensitive member ground layer 51c, and a photosensitive member photosensitive layer 51d, as shown in FIG.

As shown in FIG. 2, the intermediate transfer belt unit 40 includes an intermediate transfer belt 46 having reinforcing members 3 attached to both ends, a driving roller 41a, a transfer opposing roller 41b, and a tension roller 41c. It is configured.

The fixing unit 57 includes a heating roller 5
7a and a pressure roller 57b.

Then, the toner images of four colors are superimposed on the intermediate transfer belt 46, and the toner image on the intermediate transfer belt 46 is
After the transfer, the paper P passes through the fixing unit 57, where the toner is fixed and the operation of discharging the paper is the same as that of the above-described conventional technique. The residual toner on the photoreceptor 51a, which has been transferred to the intermediate transfer belt 46, is removed by the cleaner 5
The residual toner on the intermediate transfer belt 46 that has been removed by 1 g and has been transferred to the paper P has been cleaned by a cleaning member, here a cleaning brush 61 to which a bias has been applied, and the collected toner is removed by a waste toner box (not shown). The operation of transferring the image to the above-mentioned conventional technology is the same as that of the conventional technology.

The feature of the color image forming apparatus according to the first embodiment of the present invention resides in the relationship between the edge of the photosensitive member and the intermediate transfer belt in the image forming unit.

That is, a plurality of color toners and the exposure device 55
Photoreceptor 51a capable of forming an electrostatic latent image by
Developing roller 5 for developing the electrostatic latent image on 1a with the toner
1f, and a plurality of image forming units 51 arranged in tandem with each other and traveling around the image forming units 51 in the arrangement direction to sequentially transfer the toner images of each color developed on the photoreceptor 51a. Including an endless intermediate transfer belt unit 40 that collectively transfers a color image formed by the above to a sheet material, and a belt cleaning unit 60 that is arranged in contact with the intermediate transfer belt unit 40 and cleans the intermediate transfer belt unit 40. In the image forming apparatus, as shown in FIG.
Are larger than the width A of the intermediate transfer belt 46 ′.

In the color image forming apparatus according to the first embodiment of the present invention, the width A of the intermediate transfer belt 46 is smaller than the width B of the photoconductor 51a.
The edge 1a does not come into contact with the intermediate transfer belt 46 and does not rub.

[0035]

As is apparent from the above description, according to the present invention, a plurality of photoreceptors on which an image forming process is developed are provided, and each color image of a cyan image, a magenta image, a yellow image, and preferably a black image is formed. In a tandem-type color image forming apparatus that forms a full-color image by superposing and transferring each color image onto a sheet material at a transfer position of each photoconductor, the intermediate transfer belt The width of the photoreceptor is smaller than the width of the photoreceptor, so that the edge of the photoreceptor does not come into contact with or rub against the intermediary transfer belt. Disappears. Therefore, a long-life color image forming apparatus can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a relationship between a width of a photoconductor and a width of an intermediate transfer belt in an image forming unit of a color image forming apparatus according to a first embodiment of the present invention;

FIG. 2 is a schematic sectional view of a tandem type color image forming apparatus.

FIG. 3 is a schematic sectional view of an image forming unit in the color image forming apparatus.

FIG. 4 is a schematic sectional view of a cleaning unit in the color image forming apparatus.

FIG. 5A is a schematic cross-sectional view of a photoconductor in the color image forming apparatus. FIG. 5B is a schematic configuration diagram of a photoconductor sheet in the color image forming apparatus.

FIG. 6 is a schematic diagram of a photosensitive member width and an intermediate transfer belt width in the color image forming apparatus.

[Explanation of symbols]

 3 Reinforcing Member 40 Intermediate Transfer Belt Unit 41a Drive Roller 41b Transfer Opposite Roller 41c Tension Roller 46 Intermediate Transfer Belt 51 Image Forming Unit (Yellow) 51a Photoconductor 51b Photoconductor Base 51c Photoconductor Ground Layer 51d Photoconductor Photosensitive Layer 51f Developing Roller 51e Charger 51g Cleaner 52 Image forming unit (magenta) 53 Image forming unit (cyan) 54 Image forming unit (black) 55 Exposure device 57 Fixing unit 57a Heat roller 57b Pressure roller 58 Paper cassette 59 Transfer roller 60 Cleaning unit 61 Cleaning brush 62 Collection roller 63 Blade 64 Screw A Intermediate transfer belt width B Photoconductor width P Paper

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshihiro Mizoguchi 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. 72) Inventor Kazuhiro Ogata 1006 Kadoma, Kazuma, Osaka Pref. Matsushita Electric Industrial Co., Ltd. (72) Inventor Hiroshi Kusuda 1006 Odaka, Kazuma, Kadoma, Osaka Pref. BB21 BB42 BB43 2H032 AA05 AA15 BA01 BA09 BA23 CA04

Claims (3)

[Claims] A plurality of image forming units, each of which is provided with a developing roller for forming an electrostatic latent image on a photoreceptor by an exposure means and developing with a plurality of color toners, and arranged in tandem;
Traveling around along the arrangement direction of the image forming units,
An endless intermediate transfer belt unit that collectively transfers a color image formed by sequentially transferring toner images of each color developed on the photoconductor to a sheet material, and is arranged in contact with the intermediate transfer belt unit; A color image forming apparatus comprising: a belt cleaning unit that cleans an intermediate transfer belt unit; wherein a width of the photoconductor is larger than a width of the intermediate transfer belt. 2. A color image forming apparatus according to claim 1, wherein said photosensitive member is a photosensitive drum. 3. A color image forming apparatus according to claim 1, wherein said photosensitive member is a photosensitive belt.