Negative-positive, positive-positive exposure station

Claim 2

An apparatus, as claimed in claim 2, wherein said means to vary the electric field includes: a photoconductive layer adjacent said liquid crystal layer; wherein said means for forming a radiation pattern corresponding to an image of the first original includes: a first source of radiation; and wherein said means for forming said temporary image includes: a second source of radiation.

Claim 4

An exposure station for forming a positive electrostatic latent image on a charged photoconductive surface from either a positive original or a negative original, said exposure station comprising: means for supporting the charged photoconductive surface for exposure; a layered sandwich structure which includes in order: a first transparent electrode; a photoconductive layer; a liquid crystal layer; and a second transparent electrode; means for applying a potential between said electrodes; means for supporting the negative original; first means for exposing the photoconductive layer to an image of the negative original when said potential is applied across said electrodes to increase the electric field across portions of said liquid crystal layer corresponding to exposed portions of said photoconductive layer to form a positive temporary image in said liquid crystal layer; first image projecting means for projecting radiation along a projection path through said layered sandwich structure to expose the charged photoconductive surface to said positive temporary image to form a corresponding positive electrostatic latent image on the photoconductive surface; means for supporting the positive original; second image projecting means for projecting radiation along a path for exposing the charged photoconductive surface to the image of said positive original to form a corresponding positive electrostatic latent image on the photoconductive surface; and means for selectively enabling either said first image projecting means or said second image projecting means.

Claim 5

An exposure station, as claimed in claim 5, wherein said means for exposing the charged photoconductive surface to said positive original includes: said first radiation projecting means; and said positive original supporting means.

Claim 6

An exposure station as claimed in claim 6, wherin said means for exposing the charged photoconductive surface to said positive original further includes: means mounting said positive original supporting means for movement from a first position along said projection path and between said radiation projecting means and said layered sandwich structure, for projecting the image of the positive original through said sandwich structure to expose the charged photoconductive surface to said positive original, and a second position spaced from said optical path wherein said radiation projecting means is usable to expose the charged photoconductive surface to said positive temporary image.

Claim 7

An exposure station, as claimed in claim 5, wherein said means for exposing the charged photoconductive surface to an image of the positive original includes: second means for projecting radiation to form the corresponding positive electrostatic latent image on the charged photoconductive surface.

Claim 8

An exposure station, as claimed in claim 8, wherein said means for exposing the charged photoconductive surface to an image of a positive original further includes: a plane mirror pivotal from a first position for reflecting a radiation pattern from one of said temporary image and the positive original onto said charged photoconductive surface to a second position wherein a radiation pattern from the other of said temporary image and the positive original is projectable directly onto said charged photoconductive surface without being reflected from said mirror.

Claim 9

An exposure station for forming a positive electrostatic latent image on a charged photoconductive surface from either a positive original or a negative original, said exposure station comprising: means for supporting the charged photoconductive surface for exposure; a layered sandwich structure which includes in order: a first transparent electrode; a photoconductive layer which is responsive only to the ultraviolet portion of the electromagnetic spectrum; a liquid crystal layer; and a second transparent electrode; meAns for applying a potential between said electrodes; means for supporting the negative original; a source of ultraviolet light for projecting an image of the negative original along an optical path onto said photoconductive layer when said potential is applied across said electrodes to render exposed areas of said photoconductive layer more conductive than unexposed areas thereof to form a positive temporary image on said liquid crystal layer; a dichroic mirror for reflecting ultraviolet light and transmitting white light positioned along said optical path to reflect said negative image projected by said ultraviolet light onto said photoconductive layer; a source of white light positioned to be projected along a projection path through said dichroic mirror and said sandwich structure to expose said charged photoconductive surface to said temporary image to form a corresponding positive electrostatic latent image on said photoconductive surface; and means for supporting the positive original movable from a first position along said projection path and between said white light source and said dichroic mirror, for projecting an image of the positive original through said dichroic mirror and said sandwich structure to expose said charged photoconductive surface to an image of the positive original to form a corresponding positive electrostatic latent image on said photoconductive surface, to a second position spaced from said projection path for projecting said temporary image.

Claim 10

An exposure station, as claimed in claim 10, wherein said movable supporting means includes: lens means for projecting an image of the positive original.

Claim 11

An exposure station, as claimed in claim 10, further including: means for enabling said ultraviolet light source and said white light source and for applying said potential across said electrodes when a negative original is supported by said negative original supporting means and said positive original supporting means is in said second position and for enabling said white light source and disabling said ultraviolet light source and said potential applying means when said means for supporting said positive original is in said first position and a positive original is supported thereby.

Claim 12

An exposure station for forming a positive electrostatic latent image on a charged photoconductive surface from either a positive original or a negative original, said exposure station comprising: means for supporting the charged photoconductive surface for exposure; a layered sandwich structure which includes in order: a first transparent electrode; a photoconductive layer which is responsive only to the ultraviolet portion of the electromagnetic spectrum; a liquid crystal layer; and a second transparent electrode; means for applying a potential between said electrodes; means for supporting a negative original; a source of ultraviolet light for projecting an image of the negative original onto said photoconductive layer when said potenital is applied across said electrodes to render exposed areas of said photoconductive layer more conductive than unexposed areas thereof to form a positive temporary image on said liquid crystal layer; a first source of white light for projecting said temporary image along an optical path to expose the charged photoconductive surface to said temporary image to form a corresponding positive electrostatic latent image on the photoconductive surface; a plane mirror movable from a first position along said optical path, for reflecting said positive temporary image projected by said first white light source onto the charged photoconductive surface, to a second position spaced from said optical path; means for supporting the positive original; and a second source of white light for projecting an image of the positive original onto the charged photoconductive surface when said plane mirror is in said second position.

Claim 13

An exposurE station, as claimed in claim 13, further including: means for enabling said ultraviolet light source and said first white light source and for applying said potential across said electrodes and for disabling said second white light source when a negative original is supported by said negative original supporting means and said plane mirror is in said first position and for enabling said second white light source and for disabling said first white light source when a positive original is supported by said positive original supporting means and said plane mirror is in siad second position.

Claim 14

Apparatus for forming a latent image on a photosensitive surface from either a first original or a second original, which is the reverse of the first original, wherein the latent image of the first original is reversed and the latent image of the second original is the same as the second original, said apparatus comprising: means for supporting the photosensitive surface for exposure; a layered sandwich structure which includes in order: a first transparent electrode; a photoconductive layer; a liquid crystal layer of the type having the capacity to store an image at least temporarily; and a second transparent electrode; means for applying a first potential between said electrodes during formation of a temporary image in said liquid crystal layer; means for applying a second potential between said electrodes to erase said temporary image; means for supporting either said first original or said second original; means for projecting illumination; first control means to sequentially: enable said first potential applying means and said illumination means when the first original is in said supporting means to expose said photoconductive layer to a pattern of radiation corresponding to said first original to form said reverse temporary image in said liquid crystal layer; disables said first potential applying means when the first original is removed from said supporting means and expose said photosensitive surface to said reverse temporary image for a predetermined time to form a latent image corresponding to said reverse temporary image; and enable said second potential applying means to erase said reverse temporary image after exposure of said photosensitive surface to said temporary image; second control means to enable said illumination means when the second original is in said supporting means to expose the photosensitive surface to a radiation pattern corresponding to said second original to form a latent image corresponding to said second original; and means for selectively enabling either said first control means or said second control means.

Claim 15

An exposure station for forming a positive electrostatic latent image on a charged photoconductive surface from either a positive original or a negative original, said exposure station comprising: means for supporting the charged photoconductive surface for exposure; a layered sandwich structure which includes in order: a first transparent electrode; a photoconductive layer; a liquid crystal layer of the type having the capacity to store an image at least temporarily; and a second transparent electrode; means for applying a first potential between said electrodes during formation of a temporary image in said liquid crystal layer; means for applying a second potential between said electrodes to erase said temporary image; means for supporting either said first original or said second original; means for projecting illumination; first control means to sequentially: enable said first potential applying means and said illumination means when said negative original is in said supporting means to expose said photoconductive layer to an image of said negative original projected along an optical path to form said positive temporary image in said liquid crystal layer; disable said first potential applying means when the nEgative original is removed from said supporting means and project said positive temporary image into said charged photoconductive surface for a predetermined time to form a positive electrostatic latent image; and enable said second potential applying means to erase said positive temporary image after exposure of said photoconductive surface to said temporary image; second control means to enable said illumination means when the positive original is in said supporting means to expose the charged photoconductive surface for a predetermined period of time to an image of said positive original projected along said optical path and through said layered sandwich structure by said illumination means and to form a positive electrostatic latent image on said photoconductive surface; and means for selectively enabling either said first control means or said second control means.

Claim 16

Apparatus, as claimed in claim 16, wherein said liquid crystal layer comprises: a mixture of nematic and cholesteric liquid crystal materials.