Abstract: Photoconductive layers and elements and methods for their use are disclosed. The layers and elements include polycarbonate binders and overcoats having pendant polar groups.

Abstract: Disclosed is a device for measuring the concentration of toner in a developer mixture composed of toner and a ferromagnetic carrier material, e.g., in an electro-photographic developing device. The device comprises a measuring oscillator which comprises an inductance-including component comprising at least one coil wherein the conductor paths of the coil lie substantially in one plane; means for passing at least a portion of the developer mixture into the zone of the inductance; and means for evaluating changes in the frequency of the oscillator resulting from changes in the developer mixture composition passing over the zone of inductance. Also disclosed is an electro-photographic copying apparatus embodying the foregoing device.

Abstract: Electrostatic latent images are developed by closely positioning a developer carrying member having on a surface a developer composed of fine particles containing an organic semiconductor and being insulating at a normal state adjacent to an electrostatic latent image bearing surface in such a manner that the surface provided with the developer of the developer carrying member facaes the electrostatic latent image bearing surface, and thereby electric charges which are opposite in polarity to the electric charges of the electrostatic latent images being injected into the developer from the developer carrying member by an electric field formed between the electrostatic latent image bearing surface and the developer carrying member and the electrostatic latent images being developed by the developer.

Abstract: The present invention provides a layered electrophotographic element which comprises an electroconductive support on which there is a charge generating layer and a charge transfer layer in order, said charge generating layer being consisted essentially of a charge generating agent expressed by the general formula I ##STR1## [wherein A represents ##STR2## (wherein X is selected from the group consisting of benzene ring, naphthalene ring, indole ring, carbazole ring, benzofuran ring and substitutes thereof, Ar.sub.1 is selected from the group consisting of benzene ring, naphthalene ring, dibenzofuran ring, carbazole ring and substitutes thereof, Ar.sub.2 and Ar.sub.3 are selected from the group consisting of benzene ring, naphthalene ring and substitutes thereof, R.sub.1 and R.sub.3 are selected from the group consisting of hydrogen, lower alkyl group, phenyl group and substitutes thereof and R.sub.

Abstract: An electrophotography photosensitive plate having an interfacelayer between a substrate and a photosensitive layer. Said interfacelayer comprises the mono- or co-polymer of the unit components represented by the general formula: ##STR1## In said formula R is a hydrogen atom or a methyl group; A is ##STR2## wherein R.sub.1, R.sub.2 and R.sub.3 each are lower alkyl, phenyl or benzyl groups, and further R.sub.2 and R.sub.3 may be taken together to form a ring, or ##STR3## wherein B is a nonmetallic atom selected from the group consisting of carbon, nitrogen and sulfur atoms, necessary to form a 5-6 membered heterocycle nucleus with the --N.sup.+ .dbd.C--; X.sup.- is an anion; and Y is a substituted or unsubstituted alkylene group.

Abstract: My invention comprises an improved method of electrophotography which enables me to increase the effective speed of a photoconductor. The speed at which copies may be made is a function of the quantum of light falling on the photoconductive surface and the conductivity of the photoconductor under illumination. Since the rate at which a given photoconductor discharges the surface potential on the photoconductor through the action of light is limited, speed can be increased for a given photoconductor only by increasing the illumination. This requires energy and produces heat. My process deliberately underexposes a charged photoconductor to a light and shade image of the original to produce a weak latent electrostatic image of low contrast which is insufficient to make a satisfactory copy. I then mask the latent image with a liquid-carried toner while preventing deposition of the toner on the background areas. I then discharge the background areas with a blanket illumination of low intensity.

Abstract: Electrophotosensitive materials having the structure ##STR1## wherein: a and b represent zero, one or two;L.sup.1 through L.sup.7, which may be the same or different represent hydrogen, alkyl, aralkyl, aryl or dialkylaminoarylvinyl; or any two of L.sup.1, L.sup.2, and L.sup.3 or any two of L.sup.4, L.sup.5, L.sup.6 and L.sup.7 may, together with the atoms to which they are attached, represent the elements needed to complete a carbocyclic ring;R represents alkyl, aryl, nitroaryl or hydrogen;A.sup.1 represents aryl or a heterocyclic nucleus including those nuclei defined for A.sup.2 below;A.sup.2 represents a N-alkyl substituted nucleus of the type used in cyanine dyes.

Abstract: X-rays or .gamma.-rays are detected by irradiating a beam of high energy radiation onto a crystalline bismuth oxide compound having the formula Bi.sub.10-14 X.sub.1 O.sub.n wherein X is at least one element selected from the group consisting of Al, Ga, Ge, Si and Ti and n is a numeral substantially equal to the stoichiometric amount of oxygen within the compound. The above bismuth oxide crystalline compound may be placed in a radiation dosimeter or be applied as a radiation-sensitive coating on a cylinder or plate of an apparatus for producing electrostatic copies (i.e., an in a xerographic process or the like). This is a division of application Ser. No. 837,197, filed Sept. 28, 1977.

Abstract: An electrographic developing method for developing a latent electrostatic image on a support to a toner image by brushing the image bearing surface of the support with a magnetic brush comprising a magnetic toner which comprises core particles having a low resistivity and containing a resin and a finely divided magnetic material, and secondary particles thermally adhered to part of the outer surface of each core particle and said secondary particles consisting predominantly of an insulating resin.

Abstract: A process for preparing a lithoplate by electrophotographic means is provided wherein the toned image is fused, the photoconductive layer in the nonimage area is decoated, and finally, the fused toner is selectively removed leaving oleophilic photoconductive material as the image portion.

Abstract: A method and apparatus for recovering the residual image from an electrostatic recording surface in an electrostatic copying system which is accomplished by presenting a wiping element in pressure contact with the residual image on the recording surface whereby the residual image is substantially removed therefrom, moving a conductive member in close proximity to the toner particles being removed from the recording surface, applying a DC voltage opposite in polarity to that of the toner particles and of sufficient magnitude to the conductive member whereby the toner particles are attracted onto the surface of the conductive member, and continuously removing the toner particles from the conductive member into a collection zone for reuse in the copying system.

Abstract: Electrophotosensitive materials having the structure ##STR1## wherein R represents a basic heterocyclic nucleus as well as groups such as hydrogen, alkyl, aryl, aralkyl, etc.;A.sub.1 represents a wide variety of basic heterocyclic nuclei;A.sub.2 represents aryl or may be the same as A.sub.1 ;G represents O or S;M is 0 to 3;N is 0 to 1; andL.sup.1, L.sup.2, L.sup.3, L.sup.4 and L.sup.5 represetn hydrogen, alkyl or aryl.

Abstract: This invention relates to an electrophotographic imaging member or device and an imaging method using this imaging member, which member or device is comprised of a substrate, a layer of a charge carrier injecting material comprised of carbon or graphite dispersed in a polymer, a layer of a charge carrier transport material, a layer of a photoconductive charge carrier generating material and an electrically insulating overcoating layer.

Abstract: A photoconductive drum formed with two photoconductive layers of different spectral sensitivty is charged a first time in the dark or while rendering one of the layers conductive and a second time with an opposite polarity in the dark to form a stratified electrostatic charge pattern. Exposure to a light image of an original document causes the layers to conduct according to color. Toner particles of two colors such as red and black adhere to respective areas of the resulting electrostatic image which have opposite polarities. Transfer of the resulting toner image to a copy sheet produces a finished copy in two colors.

Abstract: An electrophotographic developer is composed of particles comprising magnetic cores which are coated with an organic substance and at least one dyestuff which passes into the vapour state at a temperature in the range of from 100.degree. to 220.degree. C. at atmospheric pressure.

Abstract: This invention relates to an improvement in a liquid developer for the development of electrostatic charge images, comprising an electrically insulating carrier liquid in which pigments or dyestuffs, resinous binders, a polarity control agent, and conventional additives are dispersed or dissolved, the improvement that the polarity control agent is a copolymer which is soluble in the carrier liquid and is composed of 1 to 50 percent by weight of N-vinyl-2-pyrrolidone and 50 to 99 percent by weight of a methacrylic acid ester.

Abstract: Electrophotographic medium which comprises a multilayer structure of materials for imaging radiant energy patterns at high speed and with high sensitivity of a degree capable of meeting and exceeding the sensitivity of silver halide film, with greater resolution than that of silver halide film of the high speed type.A method of using electrophotographic film to achieve high sensitivities and speeds.The medium comprises a transparent substrate, ohmic layer and coating of photoconductive material, all of which form a modulating structure for the radiant energy that is adapted to be projected through the substrate; a dielectric layer intimately bonded to the surface of the photoconductive coating and a conductive electrode in intimate contact with the dielectric layer.The use of the electrophotographic medium does not require initial charging; hence no means for effecting this are required.

Abstract: An electrophotographic photosensitive member having an amorphous deposition layer as a photoconductive layer, in which the amorphous deposition layer is formed by gradual increase in a substrate temperature during deposition of the photoconductive material.

Abstract: An electrophotoconductive material having the molecular formula:Cd(S.sub.x Se.sub.1-x):yCu.zCl is improved by controlling x in the range of from about 0.95 to about 0.98, y from about 0.0001 to about 0.001 and z is from about 0.001 to about 0.0015. The materials also have a relatively narrow particle size distribution and a relatively fine particle size and the surfaces relatively free of p-type copper sulfide. The improved materials exhibit and maintain a large differential between the image voltage and the background voltage of in excess of 800 volts when the material is used as an electrophotoconductive layer in a photosensitive member of equipment used in electrophotograhic copying processes.

Abstract: An electrophotographic copying method is carried out by the use of a developing material consisting of a magnetic toner of a volume resistivity within the range of 10.sup.10 to 10.sup.14 .OMEGA..multidot.cm and a non-magnetic and electrically insulating toner. During the development of an electrostatic latent image on a photoconductive support member into a toner image by means of a magnetic brush developing process, particles of both of the magnetic and non-magnetic toners are caused to deposit on an image area of the electrostatic latent image and particles of only the magnetic toner are caused to deposit on a non-image area of the electrostatic latent image. The toner image so developed is subsequently transferred from the photoconductive support member to a sheet of final support material and then fixed.