JPH03221979A - Electrophotographic image forming device - Google Patents

Abstract

PURPOSE:To realize low voltage impression so as to control generation of ozone by obtaining an even electrification by having a photo conductive layer irradiated by a specified light beam even when an uneven electrification is generated by a conductive contact member. CONSTITUTION:The photosensitive body 1 is electrified by abutting a surface of a first layer 1a of the photosensitive body 1 and rolling over it with a conductive roll 2. Next, the photosensitive body 1 is irradiated all over the width direction by the light beam which makes the first layer 1a conductive but a second layer 1b not conductive by the light emitting body 3. Therefore, the layer 1a becomes an electric conductor and the electrical charge electrified on its surface moves freely. On the other hand, since the layer 1b does not become an electric conductor, the electrical charge inside the layer 1a is evenly electrified on the surface of the layer 1b. After this, the image forming processes of exposure and developing, etc., are carried out. Thus, even when an uneven electrification is generated by the roll 2, by having it evenly irradiated by the beam, impressing the low voltage is sufficient, and the ozone generation is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image forming apparatus using an electrophotographic process such as a copying machine, a facsimile machine, or a printer.

[Prior Art] As a method for charging the surface of a photoreceptor in an electrophotographic image forming apparatus, a method using corona discharge is currently used.This method can uniformly charge the surface of the photoreceptor, but Ozone is generated, which has a negative effect on the image quality and the photoreceptor.Also, the ozone released outside the device causes discomfort in the opaque state of the device.Furthermore, it generates discharge in the air. The problem is that a fairly high voltage is required to do so.

In order to eliminate the problem of corona discharge, a contact charging method is known, for example, as disclosed in Japanese Patent Laid-Open No. 63149668, in which a brush or roller made of a conductive material is brought into contact with a photoreceptor to charge it. In the conventional contact charging method, it is difficult to bring the conductive member into uniform contact with the photoreceptor, and simply using this method has the problem that uniform charging cannot be obtained.

[Problems to be Solved by the Invention] It is an object of the present invention to provide an electrophotographic image forming apparatus that solves the above-mentioned conventional problems, generates little ozone at low voltage, and can obtain uniform charging. It is said that

[Means for Solving the Problems] The present invention solves the above problems by providing an electrophotographic method in which a conductive member to which a voltage is applied is brought into contact with the surface of a photoreceptor to charge the surface of the photoreceptor, and an electrostatic latent image is formed by image exposure. In an image forming apparatus, the conductive film is applied to the surface of the first layer of a photoreceptor having a 3N structure, which has a first layer and a second layer made of photoconductive layers having mutually different color sensitivities, and a third layer made of a conductive layer. An electrophotographic image forming apparatus characterized in that charging is performed by bringing members into contact with each other, and the surface of the photoreceptor is irradiated with light that makes the first layer conductive but does not make the second layer conductive at the same time as or after charging. It was solved by

"Function" According to the present invention, the surface of the first layer of a photoconductor having a three-layer structure, which has a first layer and a second layer consisting of photoconductive layers having mutually different color sensitivities, and a third layer consisting of a conductive layer. A conductive member, such as a roller or a brush, is brought into contact with the conductive member, and a voltage is applied to the conductive member to cause the conductive member to contact and move.The surface of the photoreceptor is charged by contact with the conductive member.At the same time as charging or after charging, a first The surface of the photoreceptor is irradiated with light that makes the layer conductive but does not make the second layer conductive.The first layer becomes conductive by the light irradiation, so even if the surface of the first layer is non-uniformly charged, the first layer becomes conductive. Charges on the surface of the layer are free to move within the first layer, resulting in a uniform charge on the surface of the second layer.Subsequent normal imaging processes such as image exposure and development cause the photoreceptor to be imaged. be done.

〔Example] The details of the present invention will be explained based on embodiments shown in the drawings.

In FIG. 1, the photoreceptor 1 is formed as a three-layer structure including a first layer 1a, a second layer lb, and a third layer 1c.

The first layer 1a and the second layer 1b are formed of photoconductive layers, but they are formed as layers having mutually different color sensitivities, and the third layer 1c is formed of a conductive layer.

A conductive roller 2 as a conductive member contacts and rolls on the surface of the photoreceptor 1, that is, the surface of the first N1a. A voltage is applied to the conductive roller 2 by the power back 4,
By grounding the third layer 1c of the photoreceptor 1, the photoreceptor 1 receives charge injection.

In this contact charging method, only the contact portion between the conductive roller 2 and the first layer 1a is charged. No matter how smooth the surfaces of the photoreceptor 1 and the conductive roller 2 are, it is difficult to bring the conductive roller 2 into contact with the surface of the photoreceptor 1 over the entire width of the photoreceptor 1. If the surface of the conductive roller 2 is scratched or has dust attached to it, it is even more difficult to make full contact with the conductive roller 2 . Therefore, in the width direction of the photoreceptor 1, charging becomes non-uniform as shown in FIG.

As shown in FIG. 1, a light emitter 3 is placed adjacent to the conductive roller 2, and is moved relative to the photoreceptor 1 together with the conductive roller 2. Although the first layer 1a of the light emitter 3 is made conductive,
The second layer lb is irradiated with light that does not become conductive over the entire width direction of the photoreceptor 1.

The light emitter 3 emits light simultaneously with or after charging by the conductive roller 2. The first layer 1a is formed by light irradiation from the light emitter 3.
Since it becomes a conductor, the charges charged on the surface of the first layer 1a can freely move within the first layer 1a. Second layer 1b
does not become a conductor even when irradiated with light from the light emitter 3, the charges in the first layer 1a are uniformly charged on the surface of the second layer 1b as shown in FIG. After this, normal electrophotographic image forming processes such as image exposure and development are carried out.

As the conductive member, a conductive brush 5 as shown in FIG. 4 can be used instead of the conductive roller 2 in FIG. 1, or a conductive blade 6 as shown in FIG. 5 can be used. In the examples shown in FIGS. 4 and 5, the light emitting body 3 is placed near the conductive member, and light is irradiated simultaneously with or after charging, as in FIG. 1.

Even in a corona discharge method in which a corona discharger is provided instead of using the above-mentioned conductive member, the above-described structure of the photoreceptor 1 and arrangement of the light-emitting body 3 can be applied to make charging uniform.

(Effects) According to the present invention, even if nonuniform charging occurs due to the conductive contact member, it is possible to obtain uniform charging, that is, surface potential, by irradiating the photoconductive layer with a specific light, which is similar to corona discharge. Application of a low voltage, which otherwise requires a high voltage, is sufficient, and it has become possible to reduce the generation of ozone.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of the charging section of the electrophotographic image forming apparatus according to the present invention, and FIG. 2 is an example of the charging state of the photoreceptor in the direction of arrow A in FIG. 1 when charging is performed only by a conductive roller. FIG. 3 is a diagram showing the charging state after light irradiation by the light emitting body after the charging shown in FIG. 2, and FIGS. 4 and 5 are explanatory diagrams of modified examples. 1... Photoreceptor 1a, 1b... Photoconductive layer lc...
・Conductive layer 2... Conductive roller (conductive member) 3...
Luminous body 4... Conductive brush (conductive part assembly) 5...
Conductive blade (conductive member)

Claims (1)

[Scope of Claims] In an electrophotographic image forming apparatus that charges the surface of a photoreceptor by bringing it into contact with a conductive member to which a voltage is applied, and forms an electrostatic latent image through image exposure, Charging is performed by bringing the conductive member into contact with the surface of the first layer of a photoreceptor having a three-layer structure having first and second layers made of photoconductive layers and a third layer made of a conductive layer. An electrophotographic image forming apparatus characterized in that the surface of the photoreceptor is irradiated with light that makes the first layer conductive but does not make the second layer conductive at the same time as or after charging.