Abstract: A particulate composite developer for electrophotography is disclosed, which has a novel dispersion structure comprising a continuous phase consisting of a homogeneous mixture of a resin and a pigment and a dispersed phase consisting of spherical particles of a soft parting or fixing material having an emulsion grade size and being dispersed in the continuous phase. This particulate developer has in combination improved adaptability to the developing operation, excellent transferring and cleaning properties, good ability to form a sharp image free of fog and good fixing property not causing an offset phenomenon.

Abstract: A developer for electrostatic images consisting essentially of particles comprising a pigment, a binder and an offset-preventing agent selected from the group consisting of aliphatic fluorocarbon compounds and fluorochlorocarbon compounds is disclosed. When this developer is used, a high offset-preventing effect can be attained at the fixing step even if the amount incorporated of the offset-preventing agent is small, and further, the developing operation can be performed in good conditions. By incorporation of this offset-preventing agent, the flowability of particles of the developer and charge characteristics of the developer can be remarkably improved.

Abstract: A particulate composite developer for electrophotography is disclosed, which has a novel dispersion structure comprising a continuous phase consisting of a homogeneous mixture of a resin and a pigment and a dispersed phase consisting of spherical particles of a soft parting or fixing material having an emulsion grade size and being dispersed in the continuous phase. This particulate developer has in combination improved adaptability to the developing operation, excellent transferring and cleaning properties, good ability to form a sharp image free of fog and good fixing property not causing an offset phenomenon.

Abstract: A developer for electrostatic images comprising a binder medium and a pigment dispersed in the binder medium is disclosed. This binder medium comprises (A) a thermoplastic or rubbery polymer containing a member selected from the group consisting of a halogen atom and a nitrile group at a concentration of at least 100 milliequivalents per 100 g of the polymer and (B) a binder having a melting temperature lower than that of the polymer (A) at an (A)/(B) mixing weight ratio of from 1/20 to 1/1. The halogen- or nitrile-containing polymer (A) is present in the form of fine particles dispersed in the continuous phase of the binder (B). This developer has good flowability and charge characteristics at the developing step and shows an excellent offset-preventing effect at the fixing step.

Abstract: In a one-component type developer for electrophotography consisting essentially of a dry blend of fixing magneto-sensitive particles and flowability- and electric resistance-controlling fine particles, when an aromatic vinyl resin and/or an acrylic resin is used as a binder resin for the magneto-sensitive particles in combination with a low molecular weight olefin resin, the magneto-sensitive particles are much improved in the property of holding the flowability- and electric resistance-controlling fine particles on the surfaces thereof. Accordingly, these fine particles cannot be substantially separated from the magneto-sensitive particles under agitation conditions, development conditions and fixing conditions. As a result, contamination of the interior of a copying machine, especially an optical system, can be completely prevented, and also contamination of the background can be completely prevented.

Abstract: An improved process for the diazo-type multicolor reproduction which can give multicolored copies excellent in the hue separation and can increase the number of copies obtained from an original treated with a color-forming agent is disclosed. This improved multicolor reproduction process is characterized by the use of a color-forming composition comprising a thermo-volatile or sublimable coupler and at least one hue separation-improving agent selected from polyalkylene oxides and polyalkylene oxide derivatives which are solid under normal conditions and fatty acid derivatives having a melting point of at least 100.degree.C.

Abstract: An improved process for diazo-type multicolor reproduction comprisingA. exposing to light an assembly comprisingI. an original comprising opaque image areas and complementary non-image areas which transmit light,Ii. a photosensitive layer containing at least one photosensitive diazonium salt (c), an azo coupler (b) and a substantially non-thermovolatile acidic substance (d), the acidic substance (d) being present in an amount of at least 5 mols per mol of the diazonium salt (c), andIii.