Electrophotographic color proofing apparatus

Apparatus for making color proof copies of a color separated positive transparency electrophotographically comprising

• A. a chassis of generally rectangular configuration and having at least a top surface, said top surface including a window spaced from the opposite ends of said chassis;
• B. track means mounted on said top surface along opposite sides thereof and extending substantially along the length thereof between the opposite ends thereof;
• C. a first carriage mounted on said track means at one end thereof for translation between a home position adjacent said window and a second position over said window;
• D. a second carriage mounted on said track means at the opposite end thereof for translation between home position adjacent the window on the opposite side thereof relative said first carriage and a second position over said window;
• E. copyboard means for carrying a color transparency thereon and mounted for movement between a load position overlying said first carriage at its home position and an imaging position overying said window,
• F. planar platen means mounted in said window for rotation therewithin through 180 degrees rotation between two horizontal conditions,
• G. an electrophotographic member having a photoconductive coating and secured on said platen means for movement therewith,
• H. charging means mounted on the leading end of said first carriage for applying a uniform electrostatic charge to the photoconductive coating of said electrophotographic member, when translated thereacross,
• I. light projection means including a light source mounted over said window,
• J. transfer roller means mounted for rotation at the leading end of the second carriage adjacent said window,
• K. means for establishing intimate engagement of said copyboard and the charged photoconductive coating of said electrophotographic member and forming thereat a latent electrostatic image thereon by exposure thereof to said light source during said engagement,
• L. a developing assembly arranged mounted within said chassis, said developing assembly including a plurality of separate developing units arranged side by side in a row, said assembly being selectively translatable along a linear path parallel to said platen means past said window below said electrophotographic member, each developing unit capable of applying developing toner material whose color corresponds to one color image component to the photoconductive coating surface during translation therepast, and means including a plate member having a planar surface horizontally arranged parallel to the path of movement of said developing device, for establishing an electrical bias between said planar surface and said photoconductive coating surface during development,
• M. the first horizontal condition of said platen disposing the photoconductive surface of said electrophotographic member facing outwardly toward said charging device, said copyboard and said transfer roller for charging, exposure and transfer but inverted facing toward said developing device during development,
• N. means for energizing only a selected one of said plural developing units during each translation of said development device past said plate means, and
• O. means for securing one edge of a transfer medium along said window and adjacent said transfer roller whereby translation of said transfer roller across said window causes said transfer medium to be engaged upon said photoconductive coating subsequent to development of said electrostatic latent image during a first pass thereover and to effect transfer of said developed image to said transfer medium during the return pass thereof across the window.

Apparatus for producing color proof copies from a color separated positive transparency electrophotographically comprising

• A. A chassis,
• B. a copyboard and a platen each mounted on said chassis,
• C. said copyboard carrying a color separated transparency and said platen having an electrophotographic member mounted thereon with the photoconductive coating thereof exposed,
• D. means for applying a charge potential on said photoconductive coating, said means comprising a corona charging device arranged adjacent said platen means for selective translation relative the photoconductive coating of said electrophotographic member,
• E. means for effecting an intimate engagement of said copyboard and the charged electrophotographic member,
• F. means for exposing said engaged copyboard and member to radiant energy from a source thereof to form a latent electrostatic image on said coating surface,
• G. means for separating the exposed photoconductive coating surface from said copyboard subsequent to formation of said latent electrostatic image thereon,
• H. a development station including individual development units capable of holding and applying developers of plural color subtracted primary colors
• I. means for placing said exposed photoconductive surface in developing proximity to said development station,
• J. means for applying a selected one of said color developers to said exposed photoconductive surface, and
• K. means for transferring developed image to a transfer medium.

A method for making color proofs electrophotographically from color separated positive transparencies, comprising the steps of:

• A. loading a color separated positive transparency on a copyboard,
• B. applying a charge potential upon the photoconductive coating of a horizontally disposed electrophotographic member,
• C. establishing an intimate engagement of said copyboard and charged coating,
• D. exposing said engaged copyboard and charged coating to a light source to form a latent electrostatic image of the transparency,
• E. rotating said electrophotographic member 180 degrees from an initial position to invert said coating to place same in developing proximity to a developing device,
• F. applying a selected color developer to said latent image by translating a development device across said coating,
• G. rotating said electrophotographic member to return same to its initial position,
• H. laying a sheet of transfer medium across said photoconductive coating in engagement therewith and
• I. transferring the developed image from said coating to said transfer medium so as to form said color proof.