Electrophotographic copying apparatus

Abstract

An electrophotographic copying apparatus having a photosensitive drum is provided with an assembly for feeding transfer material, an image transfer roller, and a fixing assembly all located upwardly of the drum, while a brush developer assembly, whole-surface exposure lamp, primary charging and contemporaneous secondary-charging exposure electrodes, and cleaning assembly are provided generally downwardly of the drum. The transfer roller and cleaning assembly are mounted on a movable frame structure which when moved away from a central frame structure permits access to and removal of the drum. A transport mechanism for an original has an adjustable path selector for recirculating an original upon insertion and expelling the original after the second traverse. The number of traverses is determined by a rotary cam. A dust-proof chamber encloses a completely independent optical assembly for projecting the image from the original onto the drum. The brush developer assembly has an adjustable cam controlled drive for a developer feed roller which supplies a fur brush transfer roller. The cleaning assembly includes a longitudinally fluted roller for wiping the drum and an axially oriented brush for cleaning the fluted roller.

What is claimed: 
     
       1. An electrophotographic copying apparatus comprising in combination: a variable path for the transportation of an original to be reproduced; means for transporting an original over said path; control means for said path and means for detecting the passage of an original both arranged in said path, .Iadd.said control means including a guide plate for guiding said original to be reproduced, guide plate positioning means adapted to shift said guide plate between first and second positions, cam means controlling operation of said guide plate positioning means and provided with a plurality of spaced pins, and cam driving means operable by signals from said detecting means to act upon said pins and shift said cam means, whereby .Iaddend.said control means .[.being.]. .Iadd.is .Iaddend.adapted to establish a continuous recirculating path in response to a signal generated by said detecting means when the latter first detects an original inserted in said path through an inlet thereto, thereby circulating an original that has been inserted through said path so as to obtain more than one copy from an original that has been inserted, said control means being further adapted to alter said path in response to a signal generated by said detecting means when the latter detects the completion of a predetermined number of circulations of an original in said path, thereby discharging an original that has been circulated; means for illuminating an original as it is being transported by said transporting means for deriving a projectable image therefrom; a photosensitive drum rotatably mounted upon a shaft; means for forming an electrophotographic image on said drum arranged around the periphery of said drum and including an optical system for projecting said projectable image upon said drum; means for feeding image transfer material; means for transferring an image from said drum to transfer material fed by said feeding means; and means for fixing an image on transfer material to which an image has been transferred. 
     
     
       2. An electrophotographic copying apparatus as claimed in claim 1, wherein said means for forming an electrophotographic image comprises charging means, developing means, and cleaning means arranged about the periphery of said drum. 
     
     
       3. An electrophotographic copying apparatus as claimed in claim 1, wherein said drum comprises a photoconductive layer and an insulating layer laminated in the order named upon an underlying base; and said means for forming an electrophotographic image comprises primary voltage application means, contemporaneous secondary-voltage-application-exposure means, developing means, and cleaning means arranged about the periphery of said drum. 
     
     
       4. An electrophotographic copying apparatus as claimed in claim 3, wherein said means for forming an electrophotographic image further comprises third voltage application means arranged about the periphery of said drum. 
     
     
       5. An electrophotographic copying apparatus as claimed in claim 1, wherein said drum comprises a photoconductive layer and an insulating layer laminated in the order named upon an underlying base; and said means for forming an electrophotographic image comprises first voltage application means, contemporaneous secondary-voltage-application-exposure means, whole-surface exposure means, developing means, and cleaning means arranged about the periphery of said drum. 
     
     
       6. An electrophotographic copying apparatus comprising in combination: means for transporting an original to be reproduced; means for illuminating an original as it is being transported by said transporting means for deriving a projectable image therefrom; a photosensitive drum rotatably mounted upon a shaft; means for forming an electrophotographic image on said drum arranged around the periphery of said drum and including means for establishing an electrostatic charge on said drum and an optical system for projecting said projectable image upon said drum; means for feeding image transfer material; means for transferring an image from said drum to transfer material fed by said feeding means comprising a transfer roller in pressure contact with said drum, and a transfer material separating belt trained around an end portion of said transfer roller for overcoming the electrostatic attraction between said drum and image transfer material fed by said feeding means and entraining transfer .[.meaterial.]. .Iadd.material .Iaddend.between said transfer roller and said belt; and means for fixing an image on transfer material to which an image has been transferred. 
     
     
       7. An electrophotographic copying apparatus as claimed in claim 6, wherein said means for forming an electrophotographic image comprises charging means, developing means, and cleaning means arranged about the periphery of said drum. 
     
     
       8. An electrophotographic copying apparatus as claimed in claim 6, wherein said drum comprises a photoconductive layer and an insulating layer laminated in the order named upon an underlying base; and said means for forming an electrophotographic image comprises primary voltage application means, contemporaneous secondary-voltage-application-exposure means, developing means, and cleaning means arranged about the periphery of said drum. 
     
     
       9. An electrophotographic copying apparatus as claimed in claim 8, wherein said means for forming an electrophotographic image further comprises whole-surface exposure means arranged about the periphery of said drum. 
     
     
       10. An electrophotographic copying apparatus as .[.claim.]. .Iadd.claimed .Iaddend.in claim 9, wherein said means for forming an electrophotographic image further comprises third voltage application means arranged about the periphery of said drum. 
     
     
       11. An electrophotographic copying apparatus comprising in combination: means for transporting an original to be reproduced; means for illuminating an original as it is being transported by said transporting means for deriving a projectable image therefrom; a photosensitive drum having a surface on which an image can be formed rotatably mounted upon a shaft; means for forming an electrophotographic image on said surface of said drum arranged around the periphery of said drum comprising charging means, developing means, cleaning means, and an optical system for projecting said projectable image upon said drum; said cleaning means including a rotatably mounted cleaning roller with a longitudinally knurled surface parallel to and in frictional rolling contact with said surface of said drum, and a belt-shaped brush disposed to move in the axial direction of and in contact with said knurled surface of said cleaning roller for cleaning said knurled surface; means for feeding image transfer material; means for transferring an image from said drum to transfer material fed by said feeding means; and means for fixing an image on transfer material to which an image has been transferred. 
     
     
       12. An electrophotographic copying apparatus as claimed in claim 11, wherein said drum comprises a photoconductive layer and an insulating layer laminated in the order named upon an underlying base; and said charging means comprises primary voltage application means, and contemporaneous secondary-voltage-application-exposure means arranged about the periphery of said drum. 
     
     
       13. An electrophotographic apparatus as claimed in claim 12, wherein said means for forming an electrophotographic image further comprises whole-surface exposure means arranged about the periphery of said drum. 
     
     
       14. An electrophotographic copying apparatus as claimed in claim 13, wherein said means for forming an electrophotographic image further comprises third voltage application means arranged about the periphery of said drum. 
     
     
       15. An electrophotographic copying apparatus comprising in combination: means for transporting an original to be reproduced; means for illuminating an original as it is being transported by said transporting means for deriving a projectable image therefrom; a photosensitive drum rotatably mounted upon a shaft; means for forming an electrophotograhic image on said drum arranged around the periphery of said drum comprising charging means, self-contained developing means within a casing, cleaning means, and an optical system for projecting said projectable image upon said drum; a support; said casing of said developing means being detachably mounted on said support, said support being movably mounted adjacent said drum for selectively moving said casing to move said developing means in parallel relationship toward and away from said drum into and out of engagement therewith; means for feeding image transfer material; means for transferring an image from said drum to transfer material fed by said feeding means; and means for fixing an image on transfer material to which an image has been transferred. 
     
     
       16. An electrophotographic copying apparatus as claimed in claim 15, wherein said drum comprises a photoconductive layer and an insulating layer laminated in the order named upon an underlying base; and said charging means comprises primary voltage application means, and contemporaneous secondary-voltage-application-exposure means arranged about the periphery of said drum. 
     
     
       17. An electrophotographic apparatus as claimed in claim 16, wherein said means for forming an electrophotographic image further comprises whole-surface exposure means arranged about the periphery of said drum. 
     
     
       18. An electrophotographic copying apparatus as claimed in claim 17, wherein said charging means further comprises third voltage application means arranged about the periphery of said drum. 
     
     
       19. An electrophotographic copying apparatus comprising in combination: means for transporting an original to be reproduced; means for illuminating an original as it is being transported by said transporting means for deriving a projectable image therefrom; a photosensitive drum rotatably mounted upon a shaft spaced from said illuminating means; means for forming an electrophotographic image on said drum arranged around the periphery of said drum and including an optical system for projecting said projectable image upon said drum; a dustproof chamber extending from a point adjacent said means for illuminating the original to a point adjacent said drum with all of the optically active elements in said optical system removably disposed as an independent assembly totally within said chamber; means for feeding image transfer material; means for transferring an image from said drum to transfer material fed by said feeding means; and means for fixing an image on transfer material to which an image has been transferred. 
     
     
       20. An electrophotographic copying apparatus as claimed in claim 19, wherein said dust-proof chamber is provided with transparent means .[.to.]. .Iadd.at .Iaddend.opposite ends of the optical path from said means for illuminating the original to said drum. 
     
     
       21. An electrophotographic copying apparatus as claimed in claim 19, wherein said means for forming an electrophotographic image comprises charging means, developing means, and cleaning means arranged about the periphery of said drum. 
     
     
       22. An electrophotographic copying apparatus as claimed in claim 19, wherein said drum comprises a photoconductive layer and an insulating layer laminated in the order named upon an underlying base; and said means for forming an electrophotographic image comprises primary voltage application means, contemporaneous primary secondary-voltage-application-exposure means, developing means, and cleaning means, arranged about the periphery of said drum. 
     
     
       23. An electrophotograhic copying apparatus as claimed in claim 22, wherein said means for forming an electrophotographic image further comprises whole-surface exposure means arranged about the periphery of said drum. 
     
     
       24. An electrophotographic copying apparatus as claimed in claim 23, wherein said means for forming an electrophotographic image further comprises third voltage application means arranged about the periphery of said drum. 
     
     
       25. An electrophotographic copying apparatus as claimed in claim 19, wherein said dust-proof chamber is disposed below said drum; and wherein said means for feeding image transfer material, said means for transferring an image, and said means for fixing an image are all disposed upwardly of said drum. 
     
     
       26. An electrophotographic copying apparatus as claimed in claim 25 wherein said means for forming an electrophotographic image comprises charging means, developing means, and cleaning means arranged about the periphery of said drum. 
     
     
       27. An electrophotographic copying apparatus as claimed in claim 25, wherein said drum comprises a photoconductive layer and an insulating layer laminated in the order named upon an underlying base; and said means for forming an electrophotographic image comprises primary voltage application means, contemporaneous secondary-voltage-application-exposure means, developing means, and cleaning means arranged about the periphery of said drum. 
     
     
       28. An electrophotographic copying apparatus according to claim 27, wherein means are provided for energizing said primary voltage application means with D. C. voltage of one polarity; and means are provided for energizing said contemporaneous secondary-voltage-application-exposure means with D. C. voltage opposite in polarity to said one polarity. 
     
     
       29. An electrophotographic copying apparatus according to claim 27, wherein means are provided for energizing said primary voltage application means with D. C. voltage; and means are provided for energizing said contemporaneous secondary-voltage-application-exposure means with A. C. voltage. 
     
     
       30. An electrophotographic copying apparatus as claimed in claim 25, wherein said drum comprises a photoconductive layer and an insulating layer laminated in the order named upon an underlying base; and said means for forming an electrophotographic image comprises first voltage application means, contemporaneous secondary-voltage-application-exposure means, whole-surface exposure means, developing means, and cleaning means arranged about the periphery of said drum. 
     
     
       31. An electrophotographic copying apparatus comprising in combination: a center structural frame assembly; a rear structural frame assembly; said rear frame assembly being movably mounted adjacent said center frame assembly for selective movement toward or away from said center frame assembly; bearing members; a shaft journaled for rotation in said bearing members; a photosensitive drum fixedly mounted on said shaft for rotation with said shaft; means secured to said shaft for communicating driving motion thereto; said bearing members being supported by said center frame assembly and secured against removal therefrom solely by the engagement of said rear frame assembly therewith when the latter is positioned toward said center frame assembly whereby upon movement of said rear frame assembly away from said center frame assembly said drum is removable along with said shaft, said bearing members, and said means for communicating driving motion; means for transporting an original to be reproduced; means for illuminating an original as it is being transported by said transporting means for deriving a projectable image therefrom; means for forming an electrophotographic image on said drum arranged around the periphery of said drum and including an optical system for projecting said projectable image upon said drum; means for feeding image transfer material; means for transferring an image from said drum to transfer material fed by said feeding means; and means for fixing an image on transfer material to which an image has been transferred. 
     
     
       32. An electrophotographic copying apparatus as claimed in claim 31, wherein said means for forming an electrophotographic image comprises charging means, developing means, and cleaning means arranged about the periphery of said drum. 
     
     
       33. An electrophotographic copying apparatus as claimed in claim 32, wherein both said means for transferring an image from said drum to said transfer material and said cleaning means are mounted on said rear frame assembly. 
     
     
       34. An electrophotographic copying apparatus as claimed in claim 31, wherein said drum comprises a photoconductive layer and an insulating layer laminated in the order named upon an underlying base; and said means for forming an electrophotographic image comprises primary voltage application means, contemporaneous secondary-voltage-application-exposure means, developing means, and cleaning means arranged about the periphery of said drum. 
     
     
       35. An electrophotographic copying apparatus as claimed in claim 34, wherein said means for forming an electrophotographic image further comprises whole-surface exposure means arranged about the periphery of said drum. 
     
     
       36. An electrophotographic copying apparatus as claimed in claim 35, wherein said means for forming an electrophotographic image further comprises third voltage application means arranged about the periphery of said drum. 
     
     
       37. An electrophotographic copying apparatus comprising in combination: means for transporting an original to be reproduced; means for illuminating an original as it is being transported by said transporting means for deriving a projectable image therefrom: a photosensitive drum rotatably mounted upon a shaft; means for forming an electrophotographic image on said drum arranged around the periphery of said drum and including an optical system for projecting said projectable image upon said drum; means for feeding image transfer material; means for transferring an image from said drum to transfer material fed by said feeding means; and means for fixing an image on transfer material to which an image has been transerred: said drum comprising a disk secured to said shaft intermediate the ends thereof, a hollow cylinder surrounding said disk and secured thereto concentric with said shaft, side plates detachably secured in opposite ends of said hollow cylinder, and a sheet-like photosensitive member having an insulating layer at the outer surface thereof wrapped around said hollow cylinder with side edge portions of said photosensitive member secured between said cylinder and said side plates. 
     
     
       38. An electrophotographic copying apparatus as claimed in claim 37, wherein said photosensitive member comprises a photoconductive layer laminated between said insulating layer and an underlying base; and said means for forming an electrophotographic image comprises primary voltage application means, contemporaneous secondary-voltage-application-exposure means, developing means, and cleaning means arranged about the periphery of said drum. 
     
     
       39. An electrophotographic copying apparatus as claimed in claim 38, wherein said means for forming an electrophotographic image further comprises whole-surface exposure means arranged about the periphery of said drum. 
     
     
       40. An electrophotographic copying apparatus as claimed in claim 39, wherein said means for forming an electrophotographic image further comprises third voltage application means arranged about the periphery of said drum. 
     
     
       41. An electrophotographic copying apparatus .[.comprisisng.]. .Iadd.comprising .Iaddend.in combination: means for transporting an original to be reproduced; means for illuminating an original as it is being transported by said transporting means for deriving a projectable image therefrom; a photosensitive drum rotatably mounted upon a shaft, said drum comprising a photoconductive layer and a nonphotosensitive insulating layer laminated in the order named upon an underlying base; means for forming an electrophotographic image on said drum arranged around the periphery of said drum comprising primary voltage application means, contemporaneous secondary-voltage-application-exposure means, whole-surface exposure means, third voltage application means, developing means, cleaning means and an optical system for projecting .[.and.]. .Iadd.said .Iaddend.projectable image upon said drum; said developing means including a hopper for holding developer, a feed roller with a roughened surface mounted for rotation adjacent an outlet of said hopper, a plurality of developing rollers rotatably mounted for contacting said photosensitive drum and transferring developer thereto, a fur brush mounted between said feed roller and said developing rollers for transferring developer from said feed roller to said developing rollers, a fog preventing roller mounted for engagement with the surface of said drum, and means for continuously rotating said feed roller to receive developer from said hopper on its roughened surface and transfer said developer at a predetermined rate to said fur brush; means for feeding image transfer material; means for transferring an image from said drum to transfer material fed by said feeding means; and means for fixing an image on transfer material to which an image has been tranferred. 
     
     
       42. An electrophotographic copying apparatus comprising in combination: means for transporting an original to be reproduced; means for illuminating an original as it is being transported by said transporting means for deriving a projectable image therefrom; a photosensitive drum rotatably mounted upon a shaft; means for forming an electrophotographic image on said drum arranged around the periphery of said drum comprising charging means, developing means, cleaning means, and an optical system for projecting said projectable image upon said drum; said developing means including a hopper for holding developer, a feed roller with a roughened surface mounted for rotation adjacent an outlet of said hopper, developing member for transferring developer to said photosensitive drum, and means for continuously rotating said feed roller to receive developer from said hopper on its roughened surface and transfer .[.and.]. .Iadd.said .Iaddend.developer at a predetermined rate to said developing member, said means for rotating said feed roller comprising a pair of cams rotatable in 180° out-of-phase relationship with each other, a cam follower in engagement with each of said cams, a ratchet pawl under the control of each of said cam followers, and a ratchet wheel joined to said feed roller and engaged by said ratchet pawls whereby upon rotation of said cams said pawls are alternately reciprocated imparting continuous rotational movement to said ratchet wheel and consequently to said feed roller; means for feeding image transfer material; means for transferring an image from said drum to transfer material fed by said feeding means; and means for fixing an image on transfer material to which an image has been transferred. 
     
     
       43. An electrophotographic copying apparatus as claimed in claim 42, wherein said drum comprises a photoconductive layer and an insulating layer laminated in order named upon an underlying base; and said charging means comprises primary voltage application means, and contemporaneous secondary-voltage-application-exposure means arranged about the periphery of said drum. 
     
     
       44. An electrophotographic copying apparatus as claimed in claim 43, wherein said means for forming an electrophotographic image further comprises whole-surface exposure means arranged about the periphery of said drum. 
     
     
       45. An electrophotographic copying apparatus as claimed in claim 44, wherein said means for forming an electrophotographic image further comprises third voltage application means arranged about the periphery of said drum. .[.46. An electrophotographic copying apparatus comprising in combination: means for transporting an original to be reproduced; means for illuminating an original as it is being transported by said transporting means for deriving a projectable image therefrom; a photosensitive drum rotatably mounted upon a shaft, said drum comprising a photoconductive layer and a non-photosensitive inslulating layer laminated in the order named upon an underlying base; means for forming an electrophotographic image on said drum arranged around said drum with an optical system disposed below said drum for projecting said projectable image upon said drum, said means for forming an electrophotographic image comprising first voltage application means, contemporaneous secondary-voltage-application-exposure means, whole surface exposure means, developing means, tertiary voltage application means, and cleaning means arranged about the periphery of said drum; means for feeding image transfer material; means for transferring an image from said drum to transfer material fed by said feeding means; and means for fixing an image on transfer material to which an image has been transferred, said three last mentioned means all being disposed upwardly of said drum..]. .Iadd. 47. An electrophotographic copying apparatus comprising in combination; means for supporting an original to be reproduced, means for illuminating the original supported by said supporting means to derive a projectable image therefrom, a photosensitive drum mounted for rotation about a central axis therethrough, means for forming on said drum an electrophotographic image of said original and including means for establishing an electrostatic charge on said drum, and an optical system for projecting said projectable image upon said drum, means for applying developer toner to said electrophotographic image on said drum to form a toner image thereof, means for feeding image transfer material to contact the toner image on said drum, means for transferring the toner image from said drum to the transfer material fed by said feeding means, and separating means for separating said transfer material from said drum, said separating means including roller means and a separator member mounted such that a portion thereof extends along a portion of said roller means, said separator member and said roller means being movable together and being positioned relatively to said drum to engage said transfer material and hold same therebetween positively to withdraw said transfer material from said drum. .Iaddend..Iadd. 48. An electrophotographic copying apparatus according to claim 47, wherein said separator member is a belt, a portion of which extends along a portion of the circumference of said roller means. .Iaddend..Iadd. 49. Apparatus according to claim 47, wherein said roller means is disposed adjacent at least one end of said transfer means. .Iaddend. .Iadd. 50. Apparatus according to claim 47, wherein said transfer means include a transfer roller positioned relatively to said drum to transfer the image formed upon said drum to the transfer material. .Iaddend..Iadd. 51. Apparatus according to claim 50, further comprising a pawl contacting said transfer roller for separating the transfer material from said transfer roller. .Iaddend..Iadd. 52. Apparatus according to claim 50, wherein said transfer roller and said roller means are integrally formed. .Iaddend..Iadd. 53. Apparatus according to claim 48, wherein said belt is an endless belt reeved around a plurality of pulleys. .Iaddend..Iadd. 54. An electrophotographic copying apparatus comprising in combination; means for supporting an original to be reproduced, means for illuminating an original as it is supported by said supporting means, for deriving a projectable image therefrom, a photosensitive drum mounted for rotation about a central axis therethrough, means for forming an electrophotographic image on said drum, and an optical system for projecting said projectable image upon said drum, means for feeding image transfer material along a path contacting a portion of the circumference of said drum for rotation therewith, means for transferring an image from said drum to the transfer material where said transfer material contacts said drum, and transfer material separating means including an elongate member extending along a marginal length of the surface of said transfer material contacting said drum, said elongate member curving away from the surface of said drum after completion of transfer of the image from said drum to said transfer material and means drawing said transfer material from the surface of said drum. .Iaddend.