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US 4,136,942 AGranted
Electrophotographic apparatus
AssigneeCanon Kabushiki Kaisha
InventorsKimio Nakahata, Yasuyuki Tamura
Life of this patent
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Abstract
An electrophotographic apparatus constructed with a photosensitive body, a primary charger to apply a substantially uniform primary charge to the photosensitive body, a secondary corona discharger to apply to the photoconductive body either an AC corona discharge or a corona discharge of an opposite polarity to that of the primary charge so as to form an electrostatic latent image on the photosensitive body, the secondary corona discharge application being effected substantially simultaneously with irradiation of an image to be reproduced, wherein the secondary corona discharger is provided with a device to control discharge conditions.
Claims19
An electrophotographic apparatus, comprising:
- (a) a three-layer photosensitive medium having an insulating layer, a photoconductive layer, and an electrically conductive substract;
- (b) means for applying a substantially uniform primary charge of a predetermined polarity to said photosensitive medium;
- (c) means for applying a secondary charge to said photosensitive medium by a corona discharger having a polarity component opposite to that of said primary charge;
- (d) means for irradiating said photosensitive member with a light image to be reproduced, said primary charge means, secondary charge means and irradiating means being operable to form an electrostatic latent image on said photosensitive medium;
- and
- (e) means for controlling said secondary charge means to change the discharging power thereof after completion of said electrostatic latent image formation.
3 more elements
An electrophotographic apparatus comprising:
- (a) a rotatable photosensitive medium;
- (b) means for forming an electrostatic latent image on said rotatable medium, said latent image forming means including corona discharger means;
- (c) means for developing the electrostatic latent image to form a developed image on said photosensitive medium;
- (d) means for transferring the developed image onto a transfer medium;
- (e) means for continuously rotating said rotatable photosensitive medium to provide a preset number of developed images for transfer onto transfer materials;
- (f) control means for operation after transfer of the preset number of the latent images to apply a current wave form to said corona discharger means, to cause the surface potential of said photosensitive medium to approach zero.
3 more elements
An electrophotographic apparatus comprising:
- (a) a rotatable photosensitive medium;
- (b) means for forming an electrostatic latent image on said rotatable photosensitive medium, said latent image forming means including corona discharging means for applying a primary charge to said rotatable photosensitive medium and means for removing the primary charge from said photosensitive medium in accordance with a pattern of an image to be reproduced;
- (c) means for developing the electrostatic latent image formed by said latent image forming means, to form a developed image;
- (d) means for tranferring the developed image onto a transfer material;
- (e) means, having an AC corona discharger and disposed in facing relation with said rotatable photosensitive medium, for causing a surface potential of said rotatable photosensitive medium to approach zero, after completion of latent image formation;
- and
- (f) means for terminating operation of said AC corona discharger after said rotatable photosensitive medium rotates through one full turn subsequent to the operation of said AC discharger for causing said surface potential to approach zero.
4 more elements
An electrophotographic apparatus comprising:
- (a) a rotatable photosensitive medium;
- (b) means for forming an electrostatic latent image on said rotatable photosensitive medium, said latent image forming means including corona discharging means for applying a primary charge to said rotatable photosensitive medium and means for removing the primary charge from said photosensitive medium in accordance with a pattern of an image to be reproduced;
- (c) means for developing the electrostatic latent image formed by said latent image forming means, to form a developed image;
- (d) means for transferring the developed image onto a transfer material;
- (e) means for rotating said rotatable photosensitive-medium and for stopping it after a predetermined time period;
- (f) AC corona discharge means for discharging said rotatable photosensitive medium to remove a charge therefrom, and to stop the discharging operation before said rotatable medium is stopped;
- and
- (g) means for exposing said rotatable medium during the rotation thereof after the developed image has been transferred, and continuing, for a particular time period, the exposing operation after the discharging operation of said AC corona discharger has been stopped.
5 more elements
Dependencies are inferred from the claim text.