Electrophotographic copying apparatus

Claim 2

A copying apparatus for producing a visible image of an original upon a copy sheet which has a conductive base and a dielectric surface, said apparatus comprising: a housing; a photoconductive base plate in said housing having a conductive backing plate and a photoconductive surface formed on said backing plate; projecting means mounted on said housing for projecting a light image of an original toward the photoconductive surface of said base plate; a carriage movably mounted in said housing between said projecting means and said base plate to travel across said photoconductive base plate; charging means mounted on said carriage for imposing a uniform electrostatic charge on the photoconductive surface of said base plate; framing means mounted on said carriage for limiting the light image projected on the photoconductive surface of said base plate to a partial slit area; copy sheet feeding means in said housing for feeding a copy sheet onto said base plate with the dielectric surface of said copy sheet facing the photoconductive surface of said base plate; charge transfer means mounted on said carriage for pressing the dielectric surface of said copy sheet against the photoconductive surface of said base plate and separating said copy sheet from said base plate; and driving means coupled to said carriage for moving said carriage across said base plate, whereby said charging means imposes the uniform electrostatic charge on the photoconductive surface of said base plate, said projecting means successively projects the partial light image onto the uniformly charged photoconductive surface of said base plate through said framing means to form an electrostatic latent image of the original, and said charge transfer means transfers said electrostatic latent image from the photoconductive surface of said base plate to the dielectric surface of said copy sheet; and developing means in said housing for receiving and developing the copy sheet to which the charge has been transfered to convert the electrostatic latent image on the dielectric surface of said copy sheet into a visible image.

Claim 3

The copying apparatus as claimed in claim 1, wherein said photoconductive base plate is a compound photoconductive plate which comprises a conductive backing plate, an amorphus selenium layer coated on said backing plate, and a poly-N-Vinylcarbazole layer coated on said amorphus selenium layer.

Claim 4

The copying apparatus as claimed in claim 1, wherein said photoconductive base plate is a plane flat plate and said housing has straight guide bars therein on which said carriage is movably mounted for reciprocating movement.

Claim 5

The copying apparatus as claimed in claim 1, wherein said projecting means comprises a mounting glass table in said housing for receiving an original on the upper surface thereof, illumination means beneath said glass table for illuminating the lower surface of the original through said glass table, and a lens unit below said glass table for transmitting the reflected light from the original and focusing a light image of said original upon said photoconductive base plate.

Claim 6

The copying apparatus as claimed in claim 1, wherein said carriage is reciprocatingly movable between a first position and a second position, and said developing means includes means for feeding the copy sheet to said developing means and said apparatus includes control means for controlling said driving means, projecting means, feeding means and developing means whereby during movement from the first position toward the second position, said charging means imposes the uniform electrostatic charge on the photoconductive surface of said base plate, said projecting means successively projects the partial light image onto the uniformly charged photoconductive surface of said base plate through said framing means to form an electrostatic latent image of the original, and charge transfer means transfers said electrostatic latent image from the photoconductive surface of said base plate to the dielectric surface of said copy sheet, and during return movement toward the first position, the copy sheet separated from said base plate is fed to said developing means.

Claim 7

The copying apparatus as claimed in claim 5, wherein said means for feeding the copy sheet to said developing means comprises a flexible belt, and a spring loaded shaft around which said belt is wound, the free end of said belt being attached to said carriage for holding the separated copy sheet thereupon during the movement of said carriage toward the second position as said belt is drawn off said shaft and feeding said copy sheet thereon to said developing means during the return movement of said carriage toward the first position as said belt is rewound on said shaft.

Claim 8

The copying apparatus as claimed in claim 1, wherein said charge transfer means includes an electrically conductive rubber roller on said carriage for pressing said copy sheet against said base plate and a copy sheet separating member in the shape of wedge on said carriage, the sharp end of saiD member being in contact with the photoconductive surface of said base plate just under said conductive rubber roller so as to lift the leading edge of said copy sheet away from said base plate and separate successively said copy sheet from said base plate to transfer the electrostatic latent image from the photoconductive surface of said base plate to the dielectric surface of said copy sheet.

Claim 9

The copying apparatus as claimed in claim 7, wherein said copy sheet separating member is made of poly-tetrafluoroethylene resin.

Claim 10

A copying apparatus for producing a visible image of an original upon a copy sheet which has a conductive base and a dielectric surface, said apparatus comprising: a housing; a photoconductive base plate in said housing having a conductive backing plate and a photoconductive surface formed on said backing plate; charging means in said housing for imposing a uniform electrostatic charge on the photoconductive surface of said base plate; projecting means mounted on said housing for projecting a light image of an original onto the uniformly charged photoconductive base plate to form an electrostatic latent image of the original upon the photoconductive surface of said base plate; copy sheet feeding means in said housing for feeding a copy sheet onto said base plate with the dielectric surface of said copy sheet facing the photoconductive surface of said base plate; charge transfer means in said housing relatively movable with respect to said base plate, said charge transfer means including an electrically conductive rubber roller for pressing said copy sheet against said base plate and a copy sheet separating member in the shape of a wedge, the sharp end of said member being in contact with the photoconductive surface of said base plate just under said conductive rubber roller, said rubber roller being electrically connected to the conductive backing plate of said base plate so that the potential of the conductive base of said copy sheet is the same is the potential of the conductive backing plate of said base plate; driving means for relatively moving said charge transfer means with respect to said photoconductive base plate so that said conductive rubber roller successively presses said copy sheet against said base plate and said copy sheet separating member lifts the leading edge of said copy sheet away from said base plate and separates successively said copy sheet from said base plate to transfer the electrostatic latent image from the photoconductive surface of said base plate to the dielectric surface of said copy sheet; and developing means in said housing for receiving and developing the copy sheet to which the charge has been transferred to convert the electrostatic latent image on the dielectric surface of said copy sheet into a visible image.

Claim 11

A copying apparatus for producing a visible image of an original upon a copy sheet which has a conductive base and a dielectric surface, said apparatus comprising: a housing; a photoconductive base plate in said housing having a conductive backing plate and a photoconductive surface formed on said backing plate; charging means in said housing for imposing a uniform electrostatic charge on the photoconductive surface of said base plate; projecting means mounted on said housing for projecting a light image of an original onto the uniformly charged photoconductive base plate to form an electrostatic latent image of the original upon the photoconductive surface of said base plate; copy sheet feeding means in said housing for feeding a copy sheet onto said base plate with the dielectric surface of said copy sheet facing the photoconductive surface of said base plate; charge transfer means in said housing relatively movable with respect to said base plate, said charge transfer means including an electrically conductive rubber roller for pressing said copy sheet against said base plate and a copy sheet separating member in the shape of a wedge, the sharp end of said member being in contact with the photoconductive surface of said base plate just under said conductive rubber roller, said rubber roller being electrically connected to the conductive backing plate of said base plate so that the potential of the conductive base of said copy sheet is the same is the potential of the conductive backing plate of said base plate; driving means for relatively moving said charge transfer means with respect to said photoconductive base plate so that said conductive rubber roller successively presses said copy sheet against said base plate and said copy sheet separating member lifts the leading edge of said copy sheet away from said base plate and separates successively said copy sheet from said base plate to transfer the electrostatic latent image from the photoconductive surface of said base plate to the dielectric surface of said copy sheet; and developing means in said housing for receiving and developing the copy sheet to which the charge has been transferred to convert the electrostatic latent image on the dielectric surface of said copy sheet into a visible image.