Electrographic transfer apparatus

Claim 2

Apparatus for electrostatically transferring a transferable image from an image-carrying member to a receiver member supported on and urged by said apparatus into pressure contact with such member, said apparatus comprising: resilient, deformable, electrically conductive means, adapted to be coupled to a source of electrical image transferring potential, said conductive means having a passage connectible to a vacuum source for vacuum tacking a receiver member to a surface of said conductive means, such passage having a longitudinal axis which, at said surface defines an oblique angle to said surface whereby said passage is closed by deformation of said means during pressure contact with the image-carrying member so that an electrical transfer potential is uniformly applied to the receiver member.

Claim 3

The invention of claim 1 wherein said conductive means is a roller mounted for rolling pressure contact with the image-carrying member.

Claim 4

A roller for electrostatically transferring a transferable image onto a receiver member, said roller comprising: an electrically conductive, hollow cylindrical core having a vacuum passage opening to the core surface, said core being connectible to a source of vacuum and a source of electrical transfer potential; and a resilient, deformable, electrically conductive cover on said core, said cover having a vacuum passage open at the outer peripheral surface of said cover and in communication with the passage in said core for tacking a receiver member to the surface of said cover, such passage in said cover having a longitudinal axis which, at the peripheral surface of said cover, defines an oblique angle to a radius of said core intersecting such axis.

Claim 5

A roller for electrostatically transferring a transferable image onto a receiver member, said roller comprising: an electrically conductive, hollow cylindrical core having a vacuum passage opening to the core surface, said core being connectible to a source of vacuum and a source of electrical transfer potential; and a resilient, deformable, electrically conductive cover on said core, said cover having a vacuum passage open at the outer peripheral surface of said cover and in communication with the passage in said core for tacking a receiver member to the surface of said cover, such passage in said cover having a longitudinal axis which, at the peripheral surface of said cover, defines an oblique angle to a radius of said core intersecting such axis.

Claim 6

For use in apparatus for transferring a transferable image from an image-carrying member to a receiver sheet, a transfer roller for rotatably supporting a receiver sheet and for applying an electrical transfer potential uniformly to such supported receiver sheet in a pressure nip between said roller and an image-carrying member, said roller comprising: an electrically conductive, hollow cylindrical core having a vacuum passage opening to the core surface, and adapted to be coupled to a source of vacuum and a source of electrical transfer potential; and a resilient, deformable, electrically conductive cover on said core, said cover having a plurality of vacuum passages open at the outer peripheral surface of said cover and in communication with said core passage, said cover passages having longitudinal axes which, at the peripheral surface of said cover, define an oblique angle to radii of said core intersecting such axes; whereby vacuum applied to said core passage is effective through said cover passages to tack a receiver sheet to the peripheral surface of said cover, and the cover passages, in the pressure nip are closed by deformation of said cover to eliminate the discontinuity at the passage openings so that an electrical transfer potential is uniformly applied to the supported receiver sheet.

Claim 7

For use in apparatus for transferring a transferable image from an image-carrying member to a receiver sheet, a transfer roller for rotatably supporting a receiver sheet and for applying an electrical transfer potential uniformly to such supported receiver sheet in a pressure nip between said roller and an image-carrying member, said roller comprising: an electrically conductive, hollow cylindrical core having a vacuum passage opening to the core surface, and adapted to be coupled to a source of vacuum and a source of electrical transfer potential; and a resilient, deformable, electrically conductive cover on said core, said cover having a plurality of vacuum passages open at the outer peripheral surface of said cover and in communication with said core passage, said cover passages having longitudinal axes which, at the peripheral surface of said cover, define an oblique angle to radii of said core intersecting such axes; whereby vacuum applied to said core passage is effective through said cover passages to tack a receiver sheet to the peripheral surface of said cover, and the cover passages, in the pressure nip are closed by deformation of said cover to eliminate the discontinuity at the passage openings so that an electrical transfer potential is uniformly applied to the supported receiver sheet.

Claim 8

Transfer roller apparatus for applying an electrical transfer potential uniformly to a receiver sheet while under pressure between the roller and an image-carrying member for transferring a transferable image from the image-carrying member to the receiver sheet, said transfer roller apparatus comprising: an electrically conductive, hollow cylindrical core having at least one vacuum passage through the core surface; means for connecting a source of electrical image transferring potential to said core; a vacuum housing mounted within said core for rotation therewith, said housing having an opening in communication with said vacuum passage; means for connecting a source of vacuum to said housing; and a resilient, deformable, electrically conductive cover on the peripheral surface of said core, said cover having at least one vacuum passage open at the outer peripheral surface of said cover and in communication with said core passage, said cover passage having a longitudinal axis which at the peripheral surface of said cover defines an oblique angle to a radius of said core intersecting such axis; whereby vacuum applied to said core passage is effective through said cover passage to tack a receiver sheet to the peripheral surface of said cover for rotation therewith, and the cover passage, in the area of pressure contact between the receiver member and the image-carrying member, is closed by deformation of said cover to eliminate the discontinuity at the passage opening so that the electrical transfer potential is uniformly applied to the receiver member.

Claim 9

Transfer roller apparatus for applying an electrical transfer potential uniformly to a receiver sheet while under pressure between the roller and an image-carrying member for transferring a transferable image from the image-carrying member to the receiver sheet, said transfer roller apparatus comprising: an electrically conductive, hollow cylindrical core having at least one vacuum passage through the core surface; means for connecting a source of electrical image transferring potential to said core; a vacuum housing mounted within said core for rotation therewith, said housing having an opening in communication with said vacuum passage; means for connecting a source of vacuum to said housing; and a resilient, deformable, electrically conductive cover on the peripheral surface of said core, said cover having at least one vacuum passage open at the outer peripheral surface of said cover and in communication with said core passage, said cover passage having a longitudinal axis which at the peripheral surface of said cover defines an oblique angle to a radius of said core intersecting such axis; whereby vacuum applied to said core passage is effective through said cover passage to tack a receiver sheet to the peripheral surface of said cover for rotation therewith, and the cover passage, in the area of pressure contact between the receiver member and the image-carrying member, is closed by deformation of said cover to eliminate the discontinuity at the passage opening so that the electrical transfer potential is uniformly applied to the receiver member.

Claim 10

The invention of claim 5 wherein said cylindrical core has a plurality of vacuum passages through the core surface along a longitudinal segment of said core, and said cover has a plurality of vacuum passages located along an element of said cover overlying such longitudinal segment, said plurality of core passages being associated with said plurality of cover passages respectively.