US 5,317,347 AGranted

Image forming apparatus

AssigneeMinolta Camera Kabushiki Kaisha

InventorsTomohiko Masuda, Ken Matsubara, Tsukasa Yagi, Koji Wakamiya, Hirohisa Kitano

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Abstract

An image forming apparatus which comprises a light shutter disposed between a source of light and an image carrier, which is electrostatically charged to a predetermined polarity, and capable of exhibiting a light transmissivity which varies according to a voltage applied to the light shutter. A first voltage of a predetermined direction is applied to the light shutter according to image information during a first period in which a first area of the image carrier passes across the light shutter, to form the electrostatic latent image on the image carrier. This electrostatic latent image is subsequently developed into a toner image. In order to substantially recover the light shutter from a light-induced fatigue, i.e., internal polarization of an electro-optical material forming the light shutter, a second voltage of a direction counter to the predetermined direction is applied to the light shutter during a second period in which a second area of the image carrier passes across the light shutter.

Claims12

Dependent claims

a voltage applying means for applying a first voltage of a predetermined direction to the light shutter according to image information during a first period in which a first area on a surface of the image carrier passes across the light shutter and also for applying a second voltage of a direction counter to said predetermined direction to the light shutter during a second period in which a second area on the surface of the image carrier passes across the light shutter;
a developing means to which a predetermined bias voltage is applied, said developing means being operable to supply a developing material onto a portion of said first area having a potential lower than the developing bias voltage as a result of operation of the light shutter;
and
a development inhibiting means operable during the second period to inhibit a supply of the developing material onto said second area, including a charger disposed between the light shutter and the developing means, said charger being operable to apply a charge of the same polarity as said predetermined polarity to the second area.

1 more element

a voltage applying means for applying a first voltage of a predetermined direction to the light shutter according to image information during a first period in which a first area on a surface of the image carrier passes across the light shutter and also for applying a second voltage of a direction counter to said predetermined direction to the light shutter during a second period in which a second area on the surface of the image carrier passes across the light shutter;
wherein said light shutter includes a light shutter head having a row of a plurality of elements, each made of electro-optical material;
a first electrode provided for each of the elements;
a second electrode provided in common to all of the elements;
and a pair of polarizing plates disposed between the light source and the light shutter head and between the light shutter head and the image carrier, respectively;
a developing means to which a predetermined bias voltage is applied, said developing means being operable to supply a developing material onto a portion of said first area having a potential lower than the developing bias voltage as a result of operation of the light shutter;
and
a development inhibiting means operable during the second period to inhibit a supply of the developing material onto said second area.

5 more elements

Dependencies are inferred from the claim text.

Facts

Application: 08/006,159Filed 19 Jan 1993 · continuation
Priority: JP 2-10567120 Apr 1990
Granted: 31 May 1994
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G03G 15/326
In which the charge pattern is formed dotwise, e.g. by a thermal head: by application of light, e.g. using a LED array
G03G 15/065
For developing: arrangements for controlling the potential of the developing electrode
G03G 15/0435
With means for controlling illumination or exposure: by introducing an optical element in the optical path, e.g. a filter
G03G
Electrography