Fuji Xerox Co., Ltd.

Kozo Oka

Taketoshi Hoshizaki

Masaki Yoshino

Kazuhiro Koseki

Shigeru Sadamatsu

Masato Ono

Kazuhiko Yanagida

Yukihiro Ishii

Fuminori Koide

Huminori Koide

A charging roll fit for use at high speed, having good maintaining property of charging characteristics in long-term use, stable in electric resistance under the environmental conditions, and having no fear of pinhole leak and photoreceptor contamination, which comprises a conductive shaft and a conductive layer formed thereon, wherein said conductive layer contains a layer in which SnO.sub.2-x -coated BaSO.sub.4 particles having an electric resistance of 0.1 to 10 .OMEGA..multidot.cm are dispersed in a resin, and the value of x is 0 to 1.

Charging roll for electrophotography

A charge roll for electrophotography wherein surface of the roll is formed from a resin layer containing BaSO.sub.4 particles coated with SnO.sub.2-x (wherein 0.ltoreq.X.ltoreq.1) is disclosed. The charge roll may comprise a roll shaft, an electroconductive elastic layer and the surface resin layer. The charge roll may further comprise an intermediate layer formed between the electroconductive elastic layer and the surface resin layer.

Charge roll for electrophotography

An electrostatic printing method is disclosed which improves the print quality by using an infrared or a flash fixing method followed by a charge recovery step whereby the image region potential of the printing master is increased by subjecting the master to one or more charging cycles.

Electrostatic printing method

In an electrostatic printing method of the type wherein a toner image is fixed on a printing master, the master is repeatedly run through a charging operation with a discharging lamp or the like maintained off, until the potential thereof reaches a value approximating a practical printing value. The lamp is then turned on and the master again repeatedly charged until the practical value is reached, prior to using the master for printing.

An electrophotographic light-sensitive element which is useful in the Carlson electrophotographic process is disclosed, comprising an electrically conductive support having provided thereon a photoconductive layer and a protective layer wherein said protective layer has a thickness of from 1 to 30 .mu.m and contains a powder of a metal oxide having a volume intrinsic resistance of 10.sup.11 .OMEGA..multidot.cm or less and a mean particle size of 0.3 .mu.m or less dispersed in a binder resin.

Electrophotographic light-sensitive element

In an electrophotographic process for the formation of an electrostatic latent image on a photosensitive element for electrophotography produced through the sequential lamination on an electrically conductive substrate of an electrically insulating layer, a photoconductive layer, and an electrically insulating surface layer by repeating a series of steps comprising a first charging; a light exposure of the entire surface; a second charging of a polarity opposite to that of the first charging; and an image-wise exposure to light, wherein the polarity between the first electrical charging and the second electrical charging is changed from positive to negative and vice versa simultaneously (either a positive image or a negative image can be obtained from an original using the same developer).

Electrophotographic process

A photosensitive material for electrophotography comprising a support having thereon a photoconductive layer and an electrically insulating layer, in which the photoconductive layer is a vacuum-deposited film substantially comprising Se with a surface layer portion of the vacuum-deposited film contacting the electrically insulating layer containing, within a thickness of about 10 .mu. or less, about 1 to about 50% by weight of As and/or Te and about 0.5 to about 1000 ppm of at least one element of Group IIIb of the Periodic Table.

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Minami-ashigara, Japan

Kozo Oka