Abstract: A dry developer composition suitable for use in the development of an electrostatic charge pattern is described. This developer composition comprises toner particles the average particle diameter whereof is comprised between 3 and 10 microns, and spacing particles the average diameter whereof is under 40 microns and at least twice the average particle diameter of the toner particles, and is characterized in that the part of spacing particles in the overall amount of spacing particles and toner particles is comprised between 1 and 8% by weight.

Abstract: A negatively-chargeable dry electrostatographic developer is disclosed containing fluorinated inorganic microparticles, and toner particles comprising an acidic binder resin having an acid value between 10 and 30 mg KOH/G and not comprising (a) charge-controlling agent(s). The developers according to this invention show excellent fluidity and have improved negative chargeability. According to a preferred mode, fluorinated silica-type microparticles are added to the developer as free flowing additive in an amount of 0.1 to 5% by weight with respect to the toner, which preferably comprises an acidic carbon black.

Abstract: Electrophotographic method of obtaining lithographic printing plates comprising the following steps: (i) uniformly electrostatically charging a photoconductor element, (ii) image-wise discharging said photoconductor element, (iii) developing the resulting electrostatic charge pattern with dry toner particles of which more than 90% by volume have an equivalent particle size diameter less than 10 microns and more than 50% by volume have an equivalent particle size diameter less than 7 microns, (iv) electrostatically transferring the developed image to a toner receiving plate, said toner receiving plate comprising a plastic film support that is thermostable to a temperature of at least 140.degree. C. and a crosslinked hydrophilic layer thereon, said layer containing infrared absorbing substances in such an amount that the reflection density of said layer in the visible spectrum is between 0.4 and 1.4, and (v) fixing the transferred toner to said toner receiving plate by infrared radiation fusing.

Abstract: The present disclosure relates to an electrophotographic method of obtaining a lithographic printing plate comprising the step of transferring a toner image from a toner image bearing member to a toner receiving plate, said toner receiving plate comprising a thermoplastic film support and a crosslinked hydrophilic layer thereon, characterized in that said crosslinked hydrophilic layer either carries on top thereof or incorporates spacing particles forming protuberances on said layer.According to a preferred embodiment, the average particle diameter by volume of the spacing particles is at least twice the average particle diameter by volume of the electrophotographic toner.

Abstract: Particulate toner material for use in the development of latent electrostatic images, wherein said particulate toner material is capable of acquiring by triboelectric contact electrification a net negative charge and contains thermoplastic resin(s) as binder in combination with a colorant and a compound capable of imparting a negative charge to the particulate toner material in contact electrification, wherein the latter compound is an anthranilic acid derivative comprising a sulfonamido-group.

Abstract: The present invention relates to a xeroprinting process, in particular a xeroprinting process comprising the following steps:(a) image-wise exposing to actinic radiation an electrostatic master having a photopolymerizable conductive layer to selectively polymerize and thereby increase resistivity in exposed areas of the layer;(b) forming a latent image of electrostatic charge by charging the master by corona discharge;(c) reversal developing the latent electrostatic image by depositing toner particles in the non-exposed areas of the layer;(d) transferring the toner image to another substrate and subsequent fusing;(e) resetting the process by cleaning and discharging the electrostatic master.According to a preferred embodiment the reversal development is effected by means of a development electrode inducing charges in the photopolymer plate opposite to the initial electrostatic image, and by means of dry electrophotographic toner.

Abstract: An electrostatic latent image developing assembly having a first feed passage for feeding developing material in a first direction, a second feed passage for feeding the developing material in a direction opposite to the first direction. A helical feed screw in the first feed passage, a helical supply screw in the second feed passsage for supplying part of the developing material to a developing sleeve, a connection between both sets of adjacent ends of such feed passages for permitting the developing material to circulate between the passages, wherein the feed screw and supply screw are disposed in parallel relation and the supply screw is provided with buckets around its periphery, the supply screw having a helical blade for advancing developing material in the second feed passage axially thereof while the buckets move the material circumferentially. Preferably, the radius of the helical blade reaches to at least one-half the depth of the buckets.

Abstract: Particulate toner material for use in the development of latent electrostatic images, wherein said particulate toner material is capable of acquiring by triboelectric contact electrification when in admixture with carrier particles a net positive charge and contains at least one thermoplastic resin as binder in combination with a colorant and a colorless compound capable of imparting a positive charge to the particulate toner material when in frictional contact with said carrier particles, characterized in that said colorless compound contains in it molecular structure at least one polyalkyl substituted piperidine group and a sterically hindered phenol group.

Abstract: Dry toner development of an electrostatic charge pattern on a recording surface is carried out with a dry toner layer formed on a donor member by electrostatic attraction resulting from a DC voltage applied across a gap between the surface of the donor member 22 and the surface of an upstream electrically conductive member 16 covered with a mixture of triboelectrically charged toner particles and magnetic carrier particles, the latter with adhering toner particles being attracted to the electrically conductive member surface by magnetic force and forming thereon a magnetic brush. The DC voltage in the gap causes selective attraction of the toner particles free of magnetic carrier particles and an AC voltage of lower peak magnitude can be superimposed on the DC voltage to set the particles in the gap in vibration and facilitate transfer across the gap.

Abstract: Particulate toner material for use in the development of latent electrostatic images, wherein said particulate toner material is capable of acquiring by triboelectric contact electrification a net positive charge and contains thermoplastic resin(s) as binder in combination with a colorant and a colorless compound capable of imparting a positive charge to the particulate toner material in contact electrification, wherein said colorless compound contains at least one piperidine nucleus substituted with an --NH-acyl group, N-substituted ureido or N-substituted thioureido group.

Abstract: In a process of image production by the steps of developing an electrostatic charge pattern with toner particles comprised of coloring matter in a thermoplastic resin binder and dispersed in a carrier liquid and fixing the pattern-wise deposited toner particles while still damp with said carrier liquid on a support by simultaneously subjecting the same to heat and pressure, the toner particles have at 120.degree. C. a melt viscosity when dry of from 500 to 100,000 Pa.s, a mean average diameter of from 0.1 to 5 .mu.m, and a ratio of coloring matter to resin binder of from 1/1 to 1/9 by weight.

Abstract: Magnetic carrier particles that can be positively charged triboelectrically and are suited for serving in magnetic brush toner-carrier development wherein said carrier particles comprise finely divided magnetically attractable powder dispersed in a resin binder which for at least 75% by weight consists of the acid-base reaction product of at least one acidic binder resin having an acid number in the range of 5 to 50 mg KOH/g, and at least one basic binder resin having free amin groups in an amount equivalent with 2 to 50 mg KOH/g and being present in an amount of at least 10% by weight with respect to such acidic resin.

Abstract: A particulate material suited for serving as carrier particles for finely-divided toner particles in magnetic brush toner-carrier development of electrostatic charge patterns, said carrier particles comprising finely divided magnetite powder dispersed in a resin binder, characterized in that said magnetite powder is a mixture of magnetites wherein one type (A) of the magnetite has an oil absorption number in the range of 10 to 20 g/100 g pigment and another type (B) of the magnetite has an oil absorption number in the range of 20 to 40 g/100 g pigment. The binder contains hydrophilic functional groups and has an acid number in the range of 5 to 50 KOH/g.

Abstract: A toner composition comprised of electrostatically attractable fusible powder particles, having an average particle size in the range of 1 to 100 .mu.m and a melt viscosity at 190.degree. C. in the range of 20 to 200 Pa.s, said powder particles comprising a coloring substance, a polymeric binder which consists essentially of a copolymer of:(1) styrene or styrene homologue,(2) an alkyl acrylate or alkyl methacrylate monomer wherein alkyl is a straight chain of at least 8 carbon atoms, and(3) a crosslinking monomer containing at least two ethylenically unsaturated groups,the binder copolymer constituting more than 50% of the total weight of the powder particles.

Abstract: In a process of image production by the steps of developing an electrostatic charge pattern with toner particles comprised of coloring matter in a thermoplastic resin binder and dispersed in a carrier liquid and fixing the pattern-wise deposited toner particles while still damp with said carrier liquid on a support by simultaneously subjecting the same to heat and pressure, the toner particles have at 120.degree. C. a melt viscosity when dry of from 500 to 100,000 Pa.s, a mean average diameter of from 0.1 to 5 .mu.m, and a ratio of coloring matter to resin binder of from 1/1 to 1/9 by weight.

Abstract: Electrophoretic process and apparatus for developing an electrostatic charge pattern carried by a dielectric surface by progressively moving that surface through a development station and simultaneously progressively advancing a layer of liquid toner (11) comprised of toner particles dispersed in a carrier liquid, through that station in proximity to said charge-carrying surface, (3), and imposing an electric field bias to cause or promote selective image-wise movement of toner particles through said liquid at said development station and deposition thereof on said charge-carrying surface in a pattern representing said electrostatic charge pattern, wherein said layer of liquid toner contains toner particles in a concentration of from 2 to 25% by weight, and including the step of applying a film of a substantially toner-free non-polar liquid which is miscible with the carrier liquid of said liquid toner and which has a specific conductivity lower than 0.

Abstract: A particulate composition of matter for magnetic brush development of electrostatic charge patterns, adapted upon mixing with magnetic carrier particles to acquire a net positive charge, which contains colorant material and thermoplastic resin binder, the colorant material comprising a salt formed from a nigrosine base and at least one carboxylic acid containing one or two carboxylic acid groups and having from 2 to 26 carbon atoms, wherein the nigrosine salt is dispersed as particles in the thermoplastic resin binder which contains a polyester derived from fumaric acid or a mixture of at least 95 mol % fumaric acid and the balance isophthalic acid and a polyol blend of propoxylated bisphenol. The charge pattern is developed by contacting the same under the influence of an applied magnetic field with a mixture of magnetic carrier particles and the particulate composition.