JP2896181B2 - Electrophotographic image forming equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus using a copying machine, a facsimile, and a printer electrophotographic process.

[Prior Art] As a method of charging the surface of a photoreceptor of an electrophotographic image forming apparatus, a method using corona discharge is widely used at present. This method can uniformly charge the surface of the photoreceptor, but discharges it in the air, so that ozone is generated, which adversely affects image quality and the photoreceptor. Further, there is a disadvantage that the ozone which has come out of the apparatus gives an unpleasant feeling to an operator of the apparatus. Further, there is a problem that a considerably high voltage is required to cause a discharge in the air.

In order to eliminate such a problem of corona discharge, a contact charging method in which a brush or a roller made of a conductive material is brought into contact with a photoreceptor to perform charging is known, for example, from JP-A-63-149668. In the conventional contact charging method, it is difficult to bring the conductive member into uniform contact with the photoreceptor, and there is a problem that uniform charging cannot be obtained by simply using this method.

[Problems to be solved by the invention]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an electrophotographic image forming apparatus which solves the above-mentioned conventional problems, generates less ozone at a low voltage, and provides uniform charging.

[Means for solving the problem]

The present invention is directed to an electrophotographic image forming apparatus that forms the electrostatic latent image by image exposure by performing charging by contacting a conductive member to which a voltage has been applied to the surface of a photoreceptor.
The conductive member is brought into contact with the surface of the first layer of a photoconductor having a three-layer structure including a first layer and a second layer made of photoconductive layers having different color sensitivities and a third layer made of a conductive layer. The problem was solved by an electrophotographic image forming apparatus characterized by irradiating the surface of the photoreceptor with light after the first layer was made conductive at the same time as or after the charging, and the second layer was not made conductive.

[Action]

According to the present invention, a conductive member is provided on the surface of a first layer of a photoconductor having a three-layer structure including a first layer and a second layer made of photoconductive layers having different color sensitivities and a third layer made of a conductive layer. For example, a roller, a brush, or the like is contacted, and a voltage is applied to the conductive member to move the conductive member. The surface of the photoconductor is charged by contact with the conductive member. At the same time as or after the charging, light is applied to the surface of the photoreceptor to make the first layer conductive but not the second layer conductive. Since the first layer is made conductive by light irradiation, even if the charge on the surface of the first layer is not uniform, the charge on the surface of the first layer can move freely in the first layer, and as a result, the second layer The surface of the layer is uniformly charged. An image is formed on the photoconductor by a subsequent normal image forming process such as image exposure and development.

〔Example〕

 The details of the present invention will be described based on an embodiment shown in the drawings.

In FIG. 1, the photosensitive member 1 has a first layer 1a, a second layer 1b, and a third layer 1b.
It is formed as a three-layer structure of the layer 1c. First layer 1a and second layer 1b
Are formed of photoconductive layers, but are formed as layers having different color sensitivities, and the third layer 1c is formed of a conductive layer.

The surface of the photoreceptor 1, that is, the surface of the first layer 1a, is brought into contact with a conductive roller 2 as a conductive member and rolls. A voltage is applied to the conductive roller 2 by the power pack 4,
When the third layer 1c of the photoconductor 1 is grounded, the photoconductor 1
Undergoes 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 photoconductor 1 and the conductive roller 2 are, it is difficult to bring the conductive roller 2 into contact with the surface of the photoconductor 1 over the entire surface in the width direction of the photoconductor 1. If the surface of the conductive roller 2 is damaged or dust adheres, it is even more difficult to contact the entire surface. Therefore, the charging becomes non-uniform in the width direction of the photoconductor 1, as shown in FIG.

As shown in FIG. 1, a light-emitting body 3 is disposed adjacent to the conductive roller 2, and relatively moves between the conductive roller 2 and the photosensitive member 1. The luminous body 3 makes the first layer 1a conductive,
The second layer 1b irradiates non-conductive light over the entire width of the photoreceptor 1.

The luminous body 3 irradiates light simultaneously with or after charging by the conductive roller 2. The first layer 1 a
Is a conductor, the electric charges charged on the surface of the first layer 1a can freely move in the first layer 1a. Since the second layer 1b does not become a conductor even when the light emitter 3 irradiates light, the first layer 1a
The charges in the inside are uniformly charged on the surface of the second layer 1b as shown in FIG. Thereafter, normal electrophotographic image forming processes such as image exposure and development are performed.

The conductive member is a fourth member instead of the conductive roller 2 of FIG.
A conductive brush 5 can be used as shown in the figure, and a conductive blade 6 can be used as shown in FIG. Also in the examples of FIGS. 4 and 5, the above-described light emitting body 3 is arranged near the conductive member, and light irradiation is performed at the same time as or after charging as in FIG.

In the corona discharge method in which a corona discharger is provided instead of using the above-described conductive member, the configuration of the photoconductor 1 and the arrangement of the light emitters 3 can be applied to uniform charging.

〔effect〕

According to the present invention, even when non-uniform charging is caused by the conductive contact member, uniform charging, that is, surface potential can be obtained by irradiating the photoconductive layer with the specified light, and a high voltage such as corona discharge can be obtained. The application of a low voltage is not required, and the generation of ozone can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of a charging section of the electrophotographic image forming apparatus according to the present invention, and FIG. 2 shows an example of a charged state of a photoconductor on an arrow A surface of FIG. FIG. 3 is a diagram showing a charged state after light irradiation by the luminous body after charging shown in FIG. 2, and FIGS. 4 and 5 are explanatory diagrams of a modification. DESCRIPTION OF SYMBOLS 1 ... Photoconductor, 1a, 1b ... Photoconductive layer 1c ... Conductive layer, 2 ... Conductive roller (conductive member) 3 ... Light emitting body, 4 ... Conductive brush (conductive member) 5 ... Conductive Blade (conductive member)

Claims (1)

(57) [Claims] 1. An electrophotographic image forming apparatus for forming an electrostatic latent image by image exposure by charging a conductive member to which a voltage has been applied on the surface of a photoreceptor to form an electrostatic latent image by image exposure. The conductive member is brought into contact with the surface of the first layer of a three-layer photosensitive member having a first layer and a second layer made of a conductive layer and a third layer made of a conductive layer, and charging is performed. An electrophotographic image forming apparatus, comprising irradiating the surface of the photoreceptor with light that makes the first layer conductive but does not make the second layer conductive at the same time or after charging.