Exposure device for controlling charge on a portion of a charged surface bordering an image frame projected on the charged surface

Abstract

Abstract A MECHANISM AND METHOD IS DISPOSED FOR CONTROLLING CHARGE ON A PORTION OF THE SURFACE OF A PHOTOCONDUCTIVE MEMBER BORDERING AN IMAGE FRAME, CONTAINING AN IMAGE AND A BACKGROUND PORTION PROJECTED ONTO THE PHOTOCONDUCTIVE SURFACE FROM AN ORIGINAL SUCH AS MICROFILM WHEREIN POSITIVE MICROFILM IS DARK OR OPAQUE BETWEEN AND AROUND ADJACENT IMAGE FRAMES AND NEGATIVE MICROFILM IS TRANSPARENT OR LIGHT TRANSMITTING BETWEEN AND AROUND ADJACENT IMAGE FRAMES. THE MECHANISM HAS AN APERTURE THROUGH WHICH THE IMAGE FRAME IS PROJECTED, SURROUNDED BY AN OPAQUE MASK PORTION FOR PREVENTING ILLUMINATION OF THE BORDER AREA ON A CHARGED PHOTOCONDUCTIVE SURFACE SURROUNDING THE IMAGE FRAME PROJECTED ONTO THE PHOTOCONDUCTIVE SURFACE FOR THOSE SITUATIONS IN WHICH POSITIVE PRINTS ARE MADE FROM NEGATIVE MICROFILM. THE MECHANISM FURTHER INCLUDES A LIGHT DIRECTING MASK PORTION SURROUNDING THE APERTURE WHICH, WHEN ACTIVATED, DIRECTS ILLUMINATION ONTO A PORTION OF THE CHARGED SURFACE OF THE PHOTOCONDUCTIVE SURFACE BORDERING THE IMAGE FRAME PROJECTED THEREON FOR DISCHARGING THE BORDER PORTION FOR THOSE SITUATIONS IN WHICH POSITIVE PRINTS ARE MADE FROM POSITIVE MICROFILM. THUS, IN ALL SITUATIONS THE CHARGE ON THE BORDER PORTION OF A PHOTOCONDUCTIVE SURFACE ADJACENT THE IMAGE FRAME IS MAINTAINED AT SUBSTANTIALLY THE SAME POTENTIAL AS BACKGROUND PORTIONS WITHIN THE IMAGE FRAME.

Inventors

• 👤 Donald J Albert

Bibliographic Details