Image forming apparatus having a photosensitive member of amorphous silicon base and system for exposing and charging the photosensitive member
First Claim
1. An electrophotographic process of forming an image through a series of steps comprising a charge eliminating step of eliminating charge from a surface of a photosensitive member having a light receiving layer, a charging step of charging the surface of the photosensitive member, a latent image exposure step of exposing the charged surface of the photosensitive member to light to form an electrostatic latent image thereon, and a development step of supplying a toner onto the electrostatic latent image to develop the image to form a toner image,wherein the light receiving layer comprises an amorphous semiconductor, and wherein the light used in the latent image exposure step is light of a wavelength within such a range that a value obtained by dividing a difference between a charging potential when the photosensitive member is not exposed to light before the charging of the photosensitive member and a charging potential when the photosensitive member is charged after exposure to light of a desired wavelength, by a sensitivity at the wavelength to make the difference between the charging potentials, is not more than 1.5 times a minimum value thereof.
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Abstract
An electrophotographic process is implemented with improved ghost memory and with high chargeability even under circumstances of increased process speed or compactified structure and the electrophotographic process forms an image on a photosensitive member having a photosensitive layer through a series of steps including steps of charge elimination, charging, latent image exposure, and development to form a toner image, wherein light used in the latent image exposure step is light of a wavelength within such a range that a value of (optical memory before charging)/(sensitivity) of the photosensitive layer is not more than 1.5 times a minimum value. The optical memory before charging means lowering in chargeability due to light irradiation before charging.
24 Citations
51 Claims
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1. An electrophotographic process of forming an image through a series of steps comprising a charge eliminating step of eliminating charge from a surface of a photosensitive member having a light receiving layer, a charging step of charging the surface of the photosensitive member, a latent image exposure step of exposing the charged surface of the photosensitive member to light to form an electrostatic latent image thereon, and a development step of supplying a toner onto the electrostatic latent image to develop the image to form a toner image,
wherein the light receiving layer comprises an amorphous semiconductor, and wherein the light used in the latent image exposure step is light of a wavelength within such a range that a value obtained by dividing a difference between a charging potential when the photosensitive member is not exposed to light before the charging of the photosensitive member and a charging potential when the photosensitive member is charged after exposure to light of a desired wavelength, by a sensitivity at the wavelength to make the difference between the charging potentials, is not more than 1.5 times a minimum value thereof.
- 26. An electrophotographic apparatus comprising a photosensitive member having a light receiving layer, a charge eliminating means for eliminating charge from a surface of the photosensitive member, a charging means for charging the surface of the photosensitive member, a latent image exposure means for exposing the charged surface of the photosensitive member to light to form an electrostatic latent image thereon, and a developing means for supplying a toner onto the electrostatic latent image to develop the image to form a toner image, wherein the light receiving layer comprises an amorphous semiconductor, and wherein the latent image exposure means comprises a light source for emitting light of a wavelength within such a range that a value obtained by dividing a difference between a charging potential when the photosensitive member is not exposed to light before the charging of the photosensitive member and a charging potential when the photosensitive member is charged after exposure to light of a desired wavelength, by a sensitivity at the wavelength to make the difference between the charging potentials, is not more than 1.5 times a minimum value thereof.
- 45. An electrophotographic process of forming an image by performing charge elimination, charging, latent image exposure and developments to a photosensitive member, wherein the photosensitive member comprises a light receiving layer comprising an amorphous material, and wherein image exposure for latent image formation is carried out using a light having a wavelength within such a range that a value of optical memory with regard to a unit contrast potential is not more than 1.5 times a minimum value thereof, and wherein exposure for charge elimination is carried out using a light source of a wavelength of not less than 600 nm nor more than 680 nm.
- 48. An electrophotographic apparatus comprising a photosensitive member, a charge eliminating means, a charging means, a latent image exposure means, a developing means and an image transfer means, wherein the photosensitive member comprises a light receiving layer comprising an amorphous material, and wherein the latent image exposure means comprises an exposure light source for use in image exposure for latent image formation which emits a light of a wavelength within such a range that a value of optical memory with regard to a unit contrast potential is not more than 1.5 times a minimum value thereof.
Specification