Photoconductive plate which is sensitive when charged either positively or negatively

Claim 2

A PHOTOSENSITIVE PLATE FOR USE IN ELECTROPHOTOGRAPHY WHICH HAS A SENSITIVITY WHEN IT IS CHARGED EITHER POSITIVELY OR NEGATIVELY SAID PHOTOSENSIITVE PLATE COMPRISING (A) AN ELECTTROCONDUCTIVE SUBSTRATE, (B) A FIRST INORGANIC PHOTOCONDUCTIVE LAYER FORAMED ON SAID ELECTOROCONDUCTIVE SUBSTRATE, SAID FIRST INORGANIC PHOTOCONDUCTIVE LAYER HAVING A THICHNESS OF AT LEAST 0 .2 MU. (C) A SUBSTANTALLY TRANSPARENT, ORGANIC INSULATING LAYER FORMED ON SAID FIRST INORGANIC PHOTOCONDUCTIVE LAYER, SAID ORGANIC INSULATING LAYER HAVING A THICKNESS OF 1 TO 30 MU, AND (D) A SECOND PHOTOCONDUCTIVE LAYER FFORMED ON SAID ORGANIC INSULATING LAYER, SAID SECOND INORGANIC PHOTOCONDUCTIVE LAYER HAVING A THICKNESS OF 0.2 TO 1 MU, WHEREIN THE FIRST INORGANIC PHOTOCONDUCTIVE LAYER (B) IS IDENTICAL WITH THE SECOND INORGANIC PHOTOCONDUCTIVE LAYER (D) WITH RESPECT TO THE TYPE OF THE PHOTOCONDUCTIVE MATERIAL, NAMELY THE N-TYPE OR P-TYPE, AND WHEN THE PHOTOCONDUCTIVE LAYER ARE OF THE N-TYPE, THE ORGANIC INSULATING LAYER IS COMPOSED OF AN ORGANIC INSULATING MATERIAL HAVING A LONG RANGE FOR ELECTRONS AND SELECTED FROM THE GROUP CONSISTING OF POLYVINYLANTHATHENE, TETRACYANOPYRENE, 2,4,7-TRIMITRE-9-FLUORENONE, DINITROANTHRATHENE AND DINITROACRIDINE, AND WHEN THE PHOTOCONDUCTUVE LAYERS ARE OF THE P-TYPE, THE ORGANIC INSULATING LAYER IS COMPOSED OF AN ORGANIC INSULATING MATERIAL HAVING A LONG RAGE FOR POSITIVE HOLES AND SELECTED FROM THE GROUP CONSISTING OF NETHYLCARBAZOLE, POLY-N-VINYLCARBAZOLE, TETRAPHENYLPYRENE, POLYACENAPHTHYLENE, PERYLENE, CRYSENE, 2,3-BENZOCRYSENE AND 6,7-BENZOPYRENE.

Claim 3

A photosensitive plate set forth in claim 1 wherein said first inorganic photoconductive layer and second inorganic photoconductive layer are composed of the same inorganic photoconductive material.

Claim 4

A photosensitive plate set forth in claim 1 wherein said first and second inorganic photoconductive layers are composed of an N-type photoconductive material selected from the group consisting of cadmium sulfide, zinc oxide, zinc sulfide, cadmium selenide and titanium dioxide.

Claim 5

A photosensitive plate set forth in claim 1 wherein said first and second inorganic photoconductive layers are composed of a P-type photoconductive material selected from the group consisting of selenium and selenium-tellurium alloys.

Claim 6

A photosensitive plate set forth in claim 1 wherein the second inorganic photoconductive layer has such a thickness that the visible ray transmission is within a range of 50 to 80 percent.

Claim 7

A photosensitive plate for use in electrophotography which has a sensitivity when it is charged either positively or negatively, said photosensitive plate comprising (a) an electroconductive substrate, (b) a first inorganic photoconductive layer of a thickness of at least 0.2 Mu formed on said electroconductive substrate, said first inorganic photo-conductive layer being composed of amorphous selenium, (c) a substantially transparent, organic insulating layer of a thickness of 1 to 30 Mu formed on said first inorganic photoconductive layer, said organic insulating layer being composed of poly-N-vinyLcarbazole, and (d) a second inorganic photoconductive layer of a thickness of 0.2 to 0.5 Mu formed on said organic insulating layer, said second inorganic photoconductive layer being composed of amorphous selenium.

Claim 8

A photosensitive plate for use in electrophotography which has a sensitivity when it is charged either positively or negatively, said photosensitive plate comprising (a) an electroconductive substrate, (b) a first inorganic photoconductive layer of a thickness of at least 0.2 Mu formed on said electroconductive substrate, said first inorganic photo-conductive layer being composed of amorphous selenium, (c) a substantially transparent, organic insulating layer of a thickness of 1 to 30 Mu formed on said first inorganic photoconductive layer, said organic insulating layer being composed of poly-N-vinyLcarbazole, and (d) a second inorganic photoconductive layer of a thickness of 0.2 to 0.5 Mu formed on said organic insulating layer, said second inorganic photoconductive layer being composed of amorphous selenium.

Claim 9

An electrostatic photographic process comprising applying a charge of a prescribed polarity uniformly on the surface of a photosensive layer of an electrophotographic plate, and exposing the charged photosensitive layer to a light image to be recorded to form an electrostatic latent image on the surface of the photosensitive layer, wherein said photosensitive plate comprises (a) an electroconductive substrate, (b) a first inorganic photoconductive layer formed on said electroconductive substrate, said first inorganic photoconductive layer having a thickness of at least 0.2 mu, (a) a substantially transparent organic insulating layer formed on said first inorganic photoconductive layer, said organic insulating layer having a thickness of 1 to 30 mu, and (d) a second inorganic photoconductive layer formed on said organic insulating layer, said second inorganic photoconductive layer having a thickness of 0.2 to 1 mu, said first inorganic photoconductive layer being identical with the second inorganic photoconductive layer with respect to the type of the photoconductive material, namely the N-type or P-type, and when the photoconductive layers are of the N-type, the organic insulating layer is composed of an organic insulating material having a long range for electrons and when the photoconductive layers are of the P-type, the organic insulating layer is composed of an organic insulating material having a long range for positive holes; and wherein an electrostatic charge of an optical polarity, a positive polarity or a negative polarity, is applied on the surface of said photosensitive layer and said charged photosensitive layer is then exposed to form thereon an electrostatic latent image of an optical charge polarity in correspondence with the polarity of the charge applied on the surface of the photosensitive layer.

Claim 10

An electrostatic photographic process comprising applying a charge of a prescribed polarity uniformly on the surface of a photosensive layer of an electrophotographic plate, and exposing the charged photosensitive layer to a light image to be recorded to form an electrostatic latent image on the surface of the photosensitive layer, wherein said photosensitive plate comprises (a) an electroconductive substrate, (b) a first inorganic photoconductive layer formed on said electroconductive substrate, said first inorganic photoconductive layer having a thickness of at least 0.2 mu, (a) a substantially transparent organic insulating layer formed on said first inorganic photoconductive layer, said organic insulating layer having a thickness of 1 to 30 mu, and (d) a second inorganic photoconductive layer formed on said organic insulating layer, said second inorganic photoconductive layer having a thickness of 0.2 to 1 mu, said first inorganic photoconductive layer being identical with the second inorganic photoconductive layer with respect to the type of the photoconductive material, namely the N-type or P-type, and when the photoconductive layers are of the N-type, the organic insulating layer is composed of an organic insulating material having a long range for electrons and when the photoconductive layers are of the P-type, the organic insulating layer is composed of an organic insulating material having a long range for positive holes; and wherein an electrostatic charge of an optical polarity, a positive polarity or a negative polarity, is applied on the surface of said photosensitive layer and said charged photosensitive layer is then exposed to form thereon an electrostatic latent image of an optical charge polarity in correspondence with the polarity of the charge applied on the surface of the photosensitive layer.