Method and apparatus for electrophotography
AssigneeCanon Kabushiki Kaisha
InventorsYujiro Ando, Katsunobu Ohara, Yukimasa Shinohara
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Abstract
An electrophotographic method by the use of a photosensitive screen having a number of tiny openings therein and by modulation of corona ion current, wherein a primary electrostatic latent image is first formed on the screen by application of electrostatic charge in conformity to an original image to be reproduced, thus a secondary electrostatic latent image is formed by modulating corona ion current for a plurality of times by the use of one and the same primary electrostatic latent image, and applying to the screen, alternately with the corona ion modulation, a corona ion current of a polarity capable of eliminating the charge polarity of the modulating corona ion current.
Claims16
An electrophotographic method, wherein a photosensitive screen having a multitude of tiny openings therein is used, a primary latent image is formed on the screen, and an ion current is modulated by the screen image to form a second latent image on another surface, comprising steps of:
- a. forming a primary electrostatic latent image by application of image light and an electrostatic charge to said screen in accordance with an original image to be reproduced;
- b. repeatedly modulating a corona ion current with said primary latent image on said screen to form a plurality of secondary latent images using the same primary electrostatic latent image formed on said screen;
- and
- c. applying an adjusting corona ion flow to said screen, wherein said adjusting corona ion flow has a polarity and a direction to eliminate charges applied to said primary latent image during said repeated modulating steps without deteriorating said primary latent image.
An electrophotographic method, wherein a photosensitive screen provided therein with a number of tiny openings is utilized, a primary latent image is formed on the screen, and ion current is modulated by the screen image to form a secondary latent image on another surface, comprising steps of:
- a. forming a primary electrostatic latent image by application of image light and an electrostatic charge to the screen in accordance with an original image to be reproduced, said photosensitive screen being capable retaining the primary image during modulation of ion current for a plurality of times by means of the same primary electrostatic latent image, wherein modulating efficiency is reduced by adherence of electric charge due to the application of modulating corona ions to the side of said screen at the time of the ion current modulation;
- b. repeatedly modulating a corona ion current with said primary latent image on said screen to form a plurality of secondary latent images using the same primary electrostatic latent image formed on said photosensitive screen;
- and
- c. applying an adjusting corona ion flow to said screen, wherein said adjusting corona ion flow has a polarity and a direction to eliminate charges applied to said primary latent image during said repeated modulating steps without deteriorating said primary latent image.
An electrophotographic apparatus for use in forming an image by modulating ion current through a photosensitive screen having a multitude of tiny openings therein, comprising, in combination:
- a. means for forming a primary electrostatic latent image on said photosensitive screen, including means for applying image light and a first corona charge to said screen;
- b. a corona discharger for repeatedly applying a corona ion current to the screen wherein said corona ion current is modulated by the same primary electrostatic latent image formed on said screen to form a plurality of secondary latent images on another surface;
- and
- c. means having a corona discharger for applying an adjusting corona ion current of a polarity to eliminate charges which adhere to said screen due to said modulating corona ion current without eliminating said primary electrostatic latent image.
An electrophotographic apparatus for use in forming an image by modulating ion current through a photosensitive screen having a multitude of openings therein, and comprising a rotatable drum having an electrically conductive member, a photoconductive member to cover said electrically conductive member, and an insulating member on said photoconductive member;
- means for forming a primary electrostatic latent image including corona discharge means and optical means for image irradiation, both of which are provided in close proximity to the outer peripheral surface of said drum-shaped screen;
- means disposed within said drum-shaped screen for applying a first corona ion flow repeatedly to said screen wherein said corona ion flow is modulated by the same primary electrostatic latent image on said screen to form a plurality of secondary latent images, and for applying a second corona ion flow to said screen for adjustment to eliminate electric charge adhered onto the screen by the corona ion flow for modulation.
Dependencies are inferred from the claim text.