Abstract: A carrier for use in developing an electrostatic or magnetic latent image in electrophotography, electrostatic recording, electrostatic printing or the like, which carrier is produced by atomizing a molten mixture of a magnetic powder and a binder resin containing a polyolefin and a polyolefin having a functional group. The polyolefin having a functional group is present in an amount ranging from about 50% by weight or less based on the total weight of the binder resin.

Abstract: A carrier for a developer comprising a core material coated with a coating material consisting essentially of a copolymer of vinylidene fluoride and trifluoroethylene or hexafluoropropylene is disclosed. The carrier causes neither fog generation in the initial stage of running nor contamination of a developing machine because of its high rate of charge increase and satisfactory resistance to surface contamination, and exhibits excellent adhesion between the core material and the coating material.

Abstract: A developer carrier is disclosed, which has a core containing a binder resin and a magnetic powder, and a surface layer thereon containing a compound having a lower critical surface tension than the binder resin. This developer when used in a magnetic brush development process provides superior charge characteristics, resistance to environmental changes, and extended life. In another aspect, the invention relates to a developer carrier produced by a process of (a) melting a carrier composition containing a binder resin, a magnetic powder and a compound having a lower critical surface tension than the binder resin, (b) spraying the molten carrier composition to form droplets, and (c) cooling the droplets with a gas stream having a temperature lower than the melting point of the composition to form substantially spherical particles having a high surface smoothness.

Abstract: A developer for electrophotography is disclosed, which comprises a toner having a colorant and a carrier having a core material that is coated with a layer containing a polymer of a fluorinated alkyl acrylate or methacrylate, the monomer constituting less than 50 wt % of the total coating material.

Abstract: A process for the production of dihydric phenoles by oxidizing diisopropylbenzenes, which comprises oxidizing diisopropylbenzenes with molecular oxygen to obtain a reaction product mixture (A) containing at least diisopropylbenzene dihydroperoxide (DHP) and diisopropylbenzene monocarbinol monohydroperoxide (HHP), supply said product mixture (A) in a form of oily phase as a solution in an aromatic hydrocarbon solvent to an agitation reactor, supplying thereto at the same time, as an aqueous phase, hydrogen peroxide at a feed rate of 1-5 moles per mole of HHP contained in the product mixture and an acid catalyst in an amount sufficient to reach a concentration in the aqueous phase of 10-40% by weight, the concentration of hydrogen peroxide in the aqueous phase being maintained at a value of at least 20% by weight and the weight ratio of the oily phase/aqueous phase being at least 10, causing oxidization of the HHP into DHP by hydrogen peroxide while maintaining the reaction temperature at 30.degree.-60.degree.

Abstract: A carrier for a developer comprising a core material coated with a coating material consisting essentially of a copolymer of vinylidene fluoride and trifluoroethylene or hexafluoropropylene is disclosed. The carrier causes neither fog generation in the initial stage of running nor contamination of a developing machine because of its high rate of charge increase and satisfactory resistance to surface contamination, and exhibits excellent adhesion between the core material and the coating material.

Abstract: A synchronizing signal extraction circuit for digital magnetic tape decks, in which a level of a synchronizing signal is differentiated and compared against a minimum level. The synchronizing signal is used for reproduction purposes only if the differentiated synchronizing signal exceeds the minimum level. Thereby, old incompletely erased synchronizing signals are masked.

Abstract: A carrier for a developer is disclosed, comprising a carrier core containing a binder resin and a magnetic powder as essential components, and a coating layer provided on the surface of the carrier core, the coating layer containing a polymer obtained by polymerizing a charge controlling monomer in the presence of polyolefin.

Abstract: A negative charging carrier for an electrophotographic developer is described, comprising a binder resin having dispersed therein a magnetic powder, wherein said carrier contains a fluorine-containing resin fine powder in an amount of from 5 to 50% by weight based on the total weight of the carrier. The carrier provides a developer for magnetic brush development having a prolonged life and a high rate of development.

Abstract: A carrier for developer is disclosed, which is produced by a process including the steps of mixing and heating a carrier material containing a binder resin and a magnetic powder and essentially free of solvent to obtain a molten dispersion of the magnetic powder in the resin; spraying the molten dispersion into droplets; and cooling the droplets to solidify the droplets into carrier particles. The carrier has excellent sphericality, high surface smoothness, and long life when used as a component of a two-component type developer in electrophotography.

Abstract: A process for producing a developer carrier is disclosed, which comprises heating a carrier composition containing a resin, magnetic particles and a compound having a lower critical surface energy than the resin, to produce a carrier particle having a higher surface concentration of the compound having a lower critical surface energy. A developer carrier having an average particle size of at least about 50 .mu.m and containing a fluorine-containing compound and fine magnetic particles dispersed in a binder resin is also disclosed. The developer carriers according to the invention when used in magnetic brush development provide superior charge generation, extended life and improved image reproduction.

Abstract: A process for producing carriers for a developer is disclosed, which comprises mixing and heating a carrier material containing a binder resin and a magnetic powder, and essentially free of solvent, to obtain a molten dispersion of the magnetic powder in the binder resin; spraying the molten dispersion into liquid droplets; and cooling the droplets to solidify the droplets into carrier particles. The process eliminates the use of solvents and produces carrier particles of superior toughness, surface smoothness, and sphericality.

Abstract: A toner composition for a two-component type developer capable of developing electrostatically charged images formed on a photoreceptor having a surface layer comprising organic substances, wherein the toner composition contains a fatty acid bisamide compound as an external additive.

Abstract: A carrier for developer is disclosed, which comprises a core having an average particle size of from 50 to 200 .mu.m and comprising fine magnetic particles dispersed in a binder resin and a polymer overcoat having a critical surface tension of from 10 to 25 dyn/cm formed on the surface of the core. The carrier has improved chargeability, high resistance to surface soiling, and high mechanical strength.