Fuji Xerox Co., Ltd.

Pioneer Electronic Corporation

Nippon Iron Powder Co. Ltd.

Masayuki Takeda

Takayoshi Aoki

Ikutaroh Nagatsuka

Yasuo Matsumura

Chiaki Suzuki

Koichi Kumashiro

Masayoshi Shinoki

Masahiro Takagi

Toshio Honjo

Kenji Uchida

Kazuhiro Itoh

Emi Takahashi

Yutaka Masumoto

Nozomu Kikuchi

Masao Mochizuki

Junichi Usui

Hirofumi Kawaguchi

Shuji Ogawa

A video signal processing circuit in which nearly 100% of a largest possible dynamic range can be used, desired contrast is obtained, and desired brightness characteristics are obtained by an increasing in luminance of a screen. The circuit has an RGB amplifier which amplifies three primary color video signals R, G, and B by a predetermined gain and in which the gain is controlled by a gain control signal, A/D converters for converting analog three primary color video signals which are generated from the RGB amplifier into digital signals respectively, inverse gamma correcting circuits for effecting an inverse gamma correction to the three primary color digital video signals respectively, an OR circuit and a peak holding circuit for detecting peak levels of the analog three primary color signals, and a gain control signal generator for generating a gain control signal in accordance with the peak levels. When the peak levels are equal to or larger than a predetermined value, the gain control signal generator supplies the gain control signal to control the RGB amplifier so as to set the level of each of the three primary color digital video signals generated by the A/D converters at a peak value.

Video signal processing circuit providing optimum signal level for inverse gamma correction

A dry toner composition containing titanium dioxide particles, the surfaces of the particles comprising an organic compound having a melting point of from about 40.degree. C. to about 150.degree. C.

Toner composition containing TiO.sub.2 particles

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.

Carrier for developer

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.

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.

Electrophotographic developer carrier particles coated with binder resin

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.

Developer for electrophotography

Coated carrier for developer

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.

Detection of a synchronizing signal in a magnetic recording/reproducing

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.

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.

Carrier for electrophotographic developer

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.

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.

Developer carrier and process for producing the same

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.

Process for producing carriers for developer

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.

Composition with fatty acid bisamide powder developer

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.

Growing community of inventors

Kanagawa, Japan

Masayuki Takeda