Abstract: A non-magnetic one-component developer comprising a substantially spherical polymerized toner which contains at least a binder resin and a colorant and has features that the volume average particle diameter is 5 to 10 &mgr;m, the proportion of particles having a particle diameter of at most 5 &mgr;m is at most 25% by number, the proportion of particles having a particle diameter of at least, 16 &mgr;m is at most 2% by volume, the standard deviation of the number particle diameter distribution is at most 1.8, and the spheroidicity represented by a ratio (dl/ds) of a length (dl) to a breadth (ds) in a particle is 1.0 to 1.3, and suitable for use in a cleaning system concurrent with development, and a developing method according to thee cleaning system concurrent with development making use of the non-magnetic one-component developer.

Abstract: A polymerized toner of a core-shell structure, comprising colored polymer particles which contain a colorant, and a polymer layer which covers each of the colored polymer particles, wherein the polymerized toner has the following features: (a) the gel content being 60 to 95% as measured by an extraction method with tetrahydrofuran; (b) the melt index being 0.5 to 15 g/10 min as measured at 150° C. and under a load of 2.16 kg; and (c) the spheroidicity represented by an average value of a ratio (rl/rs) of a length (rl) to a breadth (rs) being 1.0 to 1.2, and a production process thereof.

Abstract: A polymerized toner of a core-shell structure that colored polymer particles containing a colorant are covered with a polymer layer, wherein the polymerized toner has features that (1) the content of tetrahydrofuran-insoluble matter is 60 to 95 wt. %, and (2) the weight average molecular weight of tetrahydrofuran-soluble matter as determined by gel permeation chromatography is 50,000 to 400,000, and a production process thereof.

Abstract: A toner for development of electrostatic images, comprising at least a binder resin, a colorant and a charge control agent, wherein the charge control agent is a polar resin composed of a copolymer of a vinyl monomer and SO3X (X=H or alkali metal) group-containing (meth)acrylamide and having an SO3X group-containing (meth)acrylamide unit content of 0.1 to 10 wt. % and a weight average molecular weight of 17,000 to 25,000, and a production process of the toner.

Abstract: A polymerized toner of core-shell structure, comprising core particles composed of colored polymer particles which contain a compound having at least one >C═N+< structure in its molecule and a colorant, and a layer of a polymer having a glass transition temperature higher than that of a polymer component making up the core particles, said polymer layer covering each of the core particles, a production process thereof, an image forming process comprising using the polymerized toner, and an image forming apparatus containing the polymerized toner.

Abstract: A polymerized toner of core-shell structure, comprising core particles composed of colored polymer particles, which comprise a polyfunctional ester compound formed of a trifunctional or still higher polyfunctional polyhydric alcohol and a carboxylic acid, and a colorant, and shell which is formed of a polymer having a glass transition temperature higher than that of a polymer component making up the core particles and covers each of the core particles, a production process thereof, an image forming process comprising using the polymerized toner, and an image forming apparatus containing the polymerized toner.

Abstract: Disclosed herein are a polymerized toner of core-shell structure, comprising core particles composed of colored polymer particles having a volume average particle diameter (dv) of 0.5-20 .mu.m and a ratio (dv/dp) of the volume average particle diameter (dv) to a number average particle diameter (dp) of at most 1.7, and shell which is formed of a polymer layer having an average film thickness of 0.001-0.1 .mu.m and covers each of the core particles, and a production process thereof.

Abstract: Disclosed herein are a polymerized toner of core-shell structure, comprising core particles composed of colored polymer particles having a volume average particle diameter (dv) of 0.5-20 .mu.m and a ratio (dv/dp) of the volume average particle diameter (dv) to a number average particle diameter (dp) of at most 1.7, and shell which is formed of a polymer layer having an average film thickness of 0.001-0.1 .mu.m and covers each of the core particles, and a production process thereof.

Abstract: A binder for coating materials containing dispersed inorganic powder comprises a polyurethane resin containing (a) 2.2 to 7.0 terminal epoxy groups in one molecule in average and (b) 0.1 to 5.0% by weight as SO.sub.3 -- of a sulfonic acid salt group, 0.05 to 3.0% by weight as COO-- of a carboxylic acid salt group, or 0.02 to 1.0% by weight as N.sup.+ of a quaternary ammonium salt group in the molecule, and having a number-average molecular weight of 2,000 to 10,000. A coating material containing dispersed inorganic powder and a magnetic recording medium both use this binder. In a recording medium comprising a magnetic layer placed on a non-magnetic substrate, the magnetic layer comprises polyurethane resin (A) as a binder, vinyl chloride polymer (B) containing 0.