JP2002251046A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of suppressing the occurrence of ghost at low cost. SOLUTION: This image forming device equipped with a plurality of latent image carriers is constituted so that light from a light emitting means disposed to be opposed to any of the plurality of image carriers or disposed inside an image forming device main body is respectively guided to destaticizing positions for the plurality of image carriers by a light guide means made of diffusible material in the axial directions of the plurality of image carriers.

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 a printer or a copier employing an electrophotographic system or the like, and more particularly, to an image forming apparatus for removing charge remaining on an image carrier after transferring a toner image. It is about improvement.

[0002]

2. Description of the Related Art In recent years, in order to obtain a color image at high speed, a so-called tandem type image forming apparatus having a plurality of image forming units of, for example, yellow, magenta, cyan, and black has been known. . The conventional image forming apparatus shown in FIG. 6 includes the latent image carriers 106 to 40 of the first to fourth image forming units 100 to 400.
The toner images formed on the belt 6 are sequentially transferred to the paper transport belt 50.
The multi-color image is transferred onto the recording paper conveyed by the printer 1 to form a color image of a plurality of colors.

More specifically, in the image forming apparatus shown in FIG. 6, a first charging means 103, a first exposing means 102, and a first developing means 101 are provided around a first latent image carrier 106.
(For example, yellow), a first transfer unit 107, a first cleaning unit 105, and a first charge removing unit 104 are sequentially arranged in a clockwise direction. Further, these image forming units are provided on the sheet conveying belt 501 by the first image forming unit 100, the second image forming unit 200, and the third image forming unit.
Image forming unit 300, fourth image forming unit 400
, And these image forming units 10
A color image is formed by 0 to 400.

[0004]

However, the prior art described above has the following problems. That is, in the case of the above-described conventional image forming apparatus, as shown in FIG. 6, in order to form a full-color image at a high speed, a plurality of image forming units 100 to 400 are arranged. The forming units 100 to 400 are provided with charge removing units 104 to 404, respectively, for removing charges remaining on the first to fourth latent image carriers 106 to 406 after transfer and cleaning. Therefore, each of the image forming units 100 to 400 is the first
-The number of components disposed around the fourth latent image carriers 106 to 406 is increased by that amount, and not only the size of the device itself is increased, but also the cost is increased. Had.

For low-speed black-and-white printers and the like, in order to reduce the cost, it has been proposed to eliminate the charge removing means (lamp). However, in an image forming apparatus for forming a color image, a toner image of a plurality of colors is used. , The static elimination lamp 10
4 to 404, the image carriers 106 to 4 after the transfer are removed.
06 are charged by the charging means 103 to 403 without erasing the non-uniform residual potential, and a history (ghost) is superposed in many colors, which causes a problem in image quality.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an image forming apparatus which is low-cost and suppresses the occurrence of ghost. is there.

[0007]

According to a first aspect of the present invention, in an image forming apparatus having a plurality of latent image carriers, the image forming apparatus is provided so as to face any one of the plurality of image carriers. Or the light from the light emitting unit disposed in the image forming apparatus main body, the light guiding unit made of a material capable of diffusing in the axial direction of the plurality of image carriers, the light of the plurality of image carriers, It is configured to be guided to the static elimination position.

According to a second aspect of the present invention, there is provided an image forming apparatus comprising a plurality of latent image carriers and capable of forming a color image, the image forming apparatus being arranged to face any one of the plurality of image carriers. The plurality of image carriers are provided by light guiding means made of a material capable of diffusing light from a light emitting unit provided in the image forming apparatus main body in the axial direction of the plurality of image carriers. The light from the light emitting unit is guided to the image carrier not performing the image forming operation.
It is configured not to be guided to the image carrier.

[0009]

As described above, since it is not necessary to provide a static elimination means such as a static elimination lamp for each latent image carrier, it is possible to reduce the cost and obtain an image without ghost.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 shows a color image forming apparatus as an image forming apparatus according to Embodiment 1 of the present invention.

In FIG. 1, A indicates a main body of the color image forming apparatus.
, Four image forming units 1 for forming toner images of respective colors of yellow, magenta, cyan, and black,
2, 3, 4 are arranged parallel to each other at a certain distance. These four image forming units 1, 2,
3 and 4 are all configured similarly.

Here, each of the image forming units 1, 2,.
Configurations 3 and 4 will be described using the first image forming unit 1 as an example. The first latent image carrier 16 is a photosensitive drum formed in the shape of a drum. The photosensitive drum 16 has a structure in which an organic photoconductor layer is provided on the surface of a cylindrical base made of aluminum. . The surface of the photoreceptor drum 16 is contacted by a first rotating means (charging roll) 13 of a contact rotation type.
It is uniformly charged to about 600V. The charging means 13
Is not limited to a contact type, and may be a non-contact type charging means such as a scorotron.

Thereafter, the surface of the photosensitive drum 16 is
Image exposure based on image information is performed by the first exposure unit 12 composed of an LED array or the like, and an electrostatic latent image is formed in which the potential of the exposed portion has been removed to about -200 V. Here, the light source of the exposure unit 12 may be a laser type or an LED type.

The electrostatic latent image formed on the first latent image carrier 16 by the first exposure means 12 is
1 is developed with yellow toner. The first developing means 11 has, for example, an average particle size of 5 to 5.
7 μm negative polarity toner and an average particle diameter of 30 to 50
A developer using a two-component developer composed of a μm carrier is used.
A voltage of 450 V and an AC bias of 1.5 KVp-p / 9 KHz are applied to visualize the electrostatic latent image. Here, the developing method and bias conditions of the developing means are not particularly limited.

The toner image developed on the first latent image carrier 16 by the first developing means 11 is transferred to the first transfer means 1.
7, the image is transferred onto the sheet S conveyed by the sheet conveying belt 51. The paper S is supplied from a paper supply cassette 52 by a paper supply roll 53, is conveyed onto a paper conveyance belt 51 via a paper conveyance path 54, and is conveyed while being electrostatically attracted. Further, the transfer residual toner remaining on the first latent image carrier 16 without being transferred onto the sheet S is removed from the first latent image carrier 16 by the first cleaning unit 15. Here, the cleaning means 15 may be a blade type or a brush type rotary type,
There is no particular limitation.

As described above, by repeating the image forming process in the order of the first image forming unit 1 to the fourth image forming unit 4, the toner images of the respective colors of yellow, magenta, cyan and black are sequentially multiplexed on the paper S. Is transferred to The sheet S on which the toner images of each color are transferred is separated from the sheet conveying belt 51, then subjected to a fixing process by a fixing unit 61, and is discharged outside the apparatus, thereby completing the color image forming process. Here, each image forming unit 1
Nos. 4 to 4 may be configured to be detachable from the image forming apparatus main body A, or may be configured to be not easily detachable from the apparatus main body A, and the usage form is not particularly limited.

Next, the charge removing means will be described. In FIG. 1, as the charge removing means (light emitting means) 71, a linear arrangement of a large number of LEDs along the axial direction of the latent image carrier 46 is used. It is arranged near. The disposition position of the charge removing means 71 may be disposed at a position facing the latent image carrier or at a position distant therefrom, and is not particularly limited.

The light emitted from the charge removing means 71 is applied to the first to fourth latent image carriers 16 to
The light is guided to the neutralization position 46, and the surface of each of the latent image carriers 16 to 46 is exposed from the tip of the light guiding means 81. The light guiding means 81 is made of a material such as a colorless and transparent resin such as polycarbonate or urethane, and guides light from the charge removing means 71 to the first to fourth latent image carriers 16 to 46.
Here, the material of the light guiding means 81 may be any material that effectively guides light, other than the above-described materials, and may be polyethylene terephthalate, silicon, nylon, glass, or the like.

The latent image carriers 16 to 4 of the light guiding means 81
6 and the side corresponding to the static elimination means 71
Mirror finish to guide light efficiently. Also,
The other side that does not face the charge removing unit 71 and the latent image carrier is
Black coating or surface roughening treatment is applied to prevent light from leaking from the charge removing means 71. Further, the static elimination means 71
The other side not facing the latent image carrier may have a structure that does not affect the latent image carrier or the exposure means by a cover or the like, even if black coating or surface roughening treatment is not performed.

In FIG. 2, switching means 91 for changing the position of the static elimination means 71 is connected to the static elimination means 71. The light from 71 is oriented. Normally, in the single-color mode of only black, the other unused image forming units are stopped or operated at a lower speed than the operating image forming units, and the image forming units are stopped or operated at a lower speed than normal. The unit is configured not to irradiate light from the static eliminator 71, so that light fatigue of the latent image carrier can be prevented.

The switching means 91 may be composed of components such as a solenoid and an electromagnetic clutch, or may be transmitted from another power source and used as the switching means. Further, a shutter or the like may be provided so as to block the light path in the light guiding means 81 without changing the light distribution direction of the charge removing means 71 to shield the light.

Note that, without providing the switching means 91, FIG.
(A) As shown in (b), the light guiding means 81 is provided with static elimination means 71a and 71b, respectively, and these static elimination means 71 are provided.
The lighting may be performed by switching between a and 71b. In this case, two static elimination means 71a and 71b are required, but the switching means 91 is not required, and the number of static elimination means can be reduced as compared with the case where static elimination means are provided for all latent image carriers. Can be. In the configuration of FIG. 3A, the charge elimination unit 71a and the charge elimination unit 71b are switched, so that the charge elimination unit 71a operates in the case of color, and the charge elimination unit 71b operates in the case of black only. Further, in the configuration of FIG. 3B, the charge elimination means 71a and 71b and the charge elimination means 71b are switched, and in the case of color, the charge elimination means 71a and the charge elimination means 71b operate. In the case of black only, only the charge elimination means 71b operates. It is supposed to.

In the above configuration, in the image forming apparatus according to this embodiment, the occurrence of ghost can be suppressed at low cost as follows.

When a signal is sent to the image forming apparatus main body A by a print start input (not shown), the image forming unit 1
4 are driven, the latent image carriers 16 to 46 rotate clockwise, and the image forming process is sequentially performed. As a result, the latent image carriers 16 to 46 are charged to −600 V by the charging units 13 to 43, irradiated with yellow, magenta, cyan, and black image exposures, and developed.
47, a toner image of each color is formed.
The toner image is transferred onto the sheet S by 47, and the toner image is fixed on the sheet S by the fixing unit 61, so that a color image can be obtained.

On the other hand, in each of the latent image carriers 16 to 46, the residual toner remaining without being transferred by the transfer units 17 to 47 is collected by the cleaning units 15 to 45, and thereafter guided by the light guiding unit 81. Upon receiving the light from the charge removing means 71, the charge remaining on the surface is removed, and the apparatus is prepared for the next image forming step. In addition, the static elimination means 7
As shown in FIG. 4, the lighting timing of 1 is set to a timing substantially synchronized with a drum motor that drives the latent image carriers 16 to 46 to rotate.

With this configuration, there is no need to provide a charge removing means for each of the image forming units 1 to 4, cost can be reduced, and residual charges on the latent image carriers 16 to 46 can be removed. Ghost generation can be suppressed, and a clear color image can be obtained.

Embodiment 2 FIG. 5 shows Embodiment 2 of the present invention. The same parts as those of the above embodiment are denoted by the same reference numerals and described. Rather than directly transferring the toner image formed on each latent image carrier onto the paper, after temporarily primary-transferring once on the intermediate transfer body, and then secondary-transferring collectively onto the paper, It is configured to form a color image.

FIG. 5 shows an embodiment of an image forming apparatus using an intermediate transfer member.

Generally, each of the image forming units 1 to 4
Is obtained by sequentially superimposing and transferring the toner image formed in step (1) onto the belt-like intermediate transfer body 55, and then collectively transferring the toner image onto the sheet S by the secondary transfer means 62. It is.

The other configuration and operation are the same as those of the above-described embodiment, and the description thereof will be omitted.

[0032]

As described above, according to the present invention, the light from the static elimination means is distributed to a plurality of latent image carriers by the light guiding means, so that the static elimination means is provided for each latent image carrier. Since there is no need to provide it, costs can be reduced,
In addition, the occurrence of ghost can be reliably suppressed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a color image forming apparatus as an image forming apparatus according to Embodiment 1 of the present invention.

FIG. 2 is a configuration diagram illustrating a switching unit between a static elimination unit and a light guiding unit of the image forming apparatus according to Embodiment 1 of the present invention;

3 (a) and 3 (b) show Embodiment 1 of the present invention.
FIG. 9 is a configuration diagram illustrating another example of a switching unit between a static elimination unit and a light guiding unit of the image forming apparatus according to the first embodiment.

FIG. 4 is a timing chart showing an example of a lighting timing of a charge removing unit of the image forming apparatus according to Embodiment 1 of the present invention;

FIG. 5 is a configuration diagram showing a color image forming apparatus as an image forming apparatus according to Embodiment 1 of the present invention.

FIG. 6 is a configuration diagram showing a conventional image forming apparatus.

[Explanation of symbols]

A: Color image forming apparatus main body, 1, 2, 3, 4: Image forming unit, 16, 26, 36, 46: First to fourth latent image carriers, 71: Static elimination means (light emitting means), 81: Light guide means.

Claims (2)

[Claims] 1. An image forming apparatus having a plurality of latent image carriers, wherein the image forming device is disposed so as to face one of the plurality of image carriers, or is disposed in an image forming apparatus main body. An image characterized in that the light from the light emitting means is guided to the charge removing positions of the plurality of image carriers by light guiding means made of a material capable of diffusing in the axial direction of the plurality of image carriers. Forming equipment. 2. An image forming apparatus comprising a plurality of latent image carriers and capable of forming a color image, wherein the image forming device is disposed so as to face any one of the plurality of image carriers, or The light from the light emitting means disposed in the main body is guided to the charge removing positions of the plurality of image carriers by light guiding means made of a material capable of diffusing in the axial direction of the plurality of image carriers, thereby forming an image. An image forming apparatus, wherein light from a light emitting unit is not guided to an image carrier that does not perform an operation.