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US 3,976,375 AGranted
Electrostatic copying machine
AssigneeMinolta Camera Kabushiki Kaisha
InventorsTakaji Kurita, Susumu Tanaka
Life of this patent
Estimating the term…
Abstract
An electrophotographic copier having an endless photoconductive belt whose circumference is an integral multiple of one dimension of each of two sizes of exposure areas corresponding to two sizes of copy paper. A set of cams for each size of copy paper operates switches to control the operation for that paper size. At the end of each exposure cycle the belt is positioned so that the next exposure is made on a different area of the belt and so that the image is not located over the seam or joint in the belt. The belt is charged at the end of every copying cycle so that the next cycle can begin with immediate exposure, and the size of the area charged is set automatically when the size of the copy is selected.
Claims17
In an electrostatic copying machine of the type including an endless belt having an outwardly facing electrophotosensitive surface;
- means for supporting said endless belt for rotation about an endless path including a portion providing a flat belt surface;
- means for driving said belt about said endless path in a predetermined direction;
- corona discharge means for charging said electrophotosensitive surface of said belt and positioned upstream of said flat belt surface relative to said predetermined direction;
- total surface exposure means positioned adjacent said flat belt surface for exposing the total surface of an original and projecting an image thereof onto a predetermined portion of said flat belt surface after charging thereof by said corona discharge means;
- means positioned for feeding a transfer sheet to a location adjacent said endless belt;
- transfer means positioned adjacent said location for transferring said projected image from said belt surface to said transfer sheet;
- means for transporting said transfer sheet having said image thereon away from said endless belt;
- and copy operation control means for controlling the operation of said belt driving means, said corona discharge means and said total surface exposure means;
- the improvement wherein:
- said endless belt is formed by joining opposite ends of a length of belting at a joint extending transverse to said predetermined direction;
- said endless belt has a circumferential length equal to a first integral multiple greater than one of a first distance, said first distance being equal to a dimension of a first size transfer sheet plus the length of an interval between transfer sheets when said copying machine continuously operates, and said circumferential length being equal to a second integral multiple greater than one of a second distance, said second distance being different from said first distance and equal to a dimension of a second size transfer sheet plus the length of an interval between transfer sheets when said copying machine continuously operates;
- transfer sheet selection means coupled to said feeding means for selectively feeding said first size transfer sheets or said second size transfer sheets to said location;
- and
- said copy operation control means comprises:
- first size control means, connected to and operable by selection of said transfer sheet selection means, and connected to said belt driving means, said corona discharge means and said total surface exposure means for charging and exposing first length portions of said electrophotosensitive surface, each said first length portion being equal to said dimension of said first size transfer sheet;
- second size control means, connected to and operable by selection of said transfer sheet selection means, and connected to said belt driving means, said corona discharge means and said total surface exposure means for charging and exposing second length portions of said electrophotosensitive surface, each said second length portion being equal to said dimension of said second size transfer sheet;
- and
- each said first and second size control means including positioning means, connected to and operable by said transfer sheet selection means, and connected to said belt driving means for positioning a leading edge of one of a respective said first or second length portions at a predetermined position upstream of said corona discharge means upon actuation of a copying operation.
15 more elements
In an electrostatic copying machine of the type including an endless belt having an outwardly facing electrophotosensitive surface;
- means for supporting said endless belt for rotation about an endless path including a portion providing a flat belt surface;
- means for driving said belt about said endless path in a predetermined direction;
- corona discharge means for charging said electrophotosensitive surface of said belt and positioned upstream of said flat belt surface relative to said predetermined direction;
- total surface exposure means positioned adjacent said flat belt surface for exposing the total surface of an original and projecting an image thereof onto a predetermined portion of said flat belt surface;
- means positioned for feeding a transfer sheet to a location adjacent said endless belt;
- transfer means positioned adjacent said location for transferring said projected image from said belt surface to said transfer sheet;
- means for transporting said transfer sheet having said image thereon away from said endless belt;
- and copy operation control means for controlling the operation of said belt driving means, said corona discharge means and said total surface exposure means;
- the improvement wherein:
- said copy operation control means comprises means for operating said corona discharge means, said belt driving means and said total surface exposure means to provide said electrostatic copying machine with every copying operation commencing with operation of said total surface exposure means to project an image onto a predetermined portion of said flat belt surface charged in the preceding copying operation, and terminating with operation of said corona discharge means to charge a predetermined portion of said electrophotosensitive surface to be used in a subsequent copying operation, said operating means thus comprising means for precharging said subsequent copying operation predetermined portion.
7 more elements
In an electrostatic copying machine of the type including an endless belt having an outwardly facing electrophotosensitive surface;
- means for supporting said endless belt for rotation about an endless path including a portion providing a flat belt surface;
- means for driving said belt about said endless path in a predetermined direction;
- corona discharge means for charging said electrophotosensitive surface of said belt and positioned upstream of said flat belt surface relative to said predetermined direction;
- total surface exposure means positioned adjacent said flat belt surface for exposing the total surface of an original and projecting an image thereof onto a predetermined portion of said flat belt surface;
- means positioned for feeding a transfer sheet to a location adjacent said endless belt;
- transfer means positioned adjacent said location for transferring said projected image from said belt surface to said transfer sheet;
- means for transporting said transfer sheet having said image thereon away from said endless belt;
- and copy operation control means for controlling the operation of said belt driving means, said corona discharge means and said total surface exposure means;
- the improvement wherein:
- said endless belt has a circumferential length equal to a first integral multiple greater than one of a first distance, said first distance being equal to a dimension of a first size transfer sheet plus the length of an interval between transfer sheets when said copying machine continuously operates, and said circumferential length being equal to a second integral multiple greater than one of a second distance, said second distance being different from said first distance and equal to a dimension of a second size transfer sheet plus the length of an interval between transfer sheets when said copying machine continuously operates;
- transfer sheet selection means is coupled to said feeding means for selectively feeding said first size transfer sheets or said second size transfer sheets to said location;
- and
- said copy operation control means comprises means, operable after the termination of every copying operation, for operating said corona discharge means to charge a predetermined portion of said electrophotosensitive surface of said belt to be used for a copy in the next subsequent copying operation before commencement of said subsequent copying operation, said operating means thus comprising means for precharging said subsequent copying operation predetermined portion;
- first size control means, connected to and operable by selection of said transfer sheet selection means, and connected to said belt driving means and said total surface exposure means for exposing first length portions of said electrophotosensitive surface, each said first length portion being equal to said dimension of said first size transfer sheet;
- and second size control means, connected to and operable by selection of said transfer sheet selection means, and connected to said belt driving means and said total surface exposure means for exposing second length portions of said electrophotosensitive surface, each said second length portion being equal to said dimension of said second size transfer sheet.
12 more elements
Dependencies are inferred from the claim text.