Fuji Photo Film Company, Limited

Rank Xerox Ltd.

Xerox Corporation

Hajime Miyatuka

Satoru Honjo

Yasuo Tamai

Akira Kasuga

Akihiro Matsufuji

Goro Akashi

Seiji Matsumoto

Sadao Osawa

Shizuo Umemura

Tsutomu Sugisaki

Takashi Saida

Tasuo Tamai

Masaya Yamamoto

A process for preparing a ferromagnetic metal powder and a magnetic recording medium utilizing that powder are disclosed. The ferromagnetic metal powder is prepared by heat-treating an acicular iron oxyhydroxide or an acicular iron oxide powder prepared from the acicular iron oxyhydroxide in a non-reducing gas at a temperature of from 300.degree. C. to 1000.degree. C. or in a reducing gas at a temperature of from 150.degree. C. to 500.degree. C. The heat-treated material is washed and then reduced under heating. The ferromagnetic metal powder prepared in this manner is dispersed in a binder and cated on a non-magnetic base to form a magnetic recording medium. By utilizing the washing step followed by heat-treating preparing the ferromagnetic metal powder a large amount of water soluble impurities are removed from the metal powder. The metal powder produced according to this disclosed process as excellent oxidation stability and ability to resist corrosion. Accordingly, the magnetic recording medium prepared utilizing this powder has an excellent ability to resist oxidation and corrosion even when subjected to adverse conditions.

Process for preparing ferromagnetic metal powder and a magnetic

A magnetic recording medium is disclosed. The medium is comprised of a support having a magnetic layer coated thereon. The magnetic layer is comprised of a ferromagnetic metal powder and a binder. The ferromagnetic metal powder has a specific surface area of not less than 30 m.sup.2 /g. The magnetic layer is further comprised of a fatty acid and a fatty acid ester in a total amount of 2 to 10 wt % based on the weight of the ferromagnetic metal powder. The proportion of the fatty acid ester is 15 to 60 wt % based on the total weight of the fatty acid and the fatty acid ester. The surface roughness of the magnetic layer is not more than 0.03.mu.. The recording medium has excellent video characteristics obtained by the use of fine metal particles having the disclosed specific surface area and by increasing the surface properties of the magnetic layer so that spacing loss between the recording or reproducing head and the recording tape is decreased and output level is increased and modulation noise is decreased so that the video S/N is increased.

Magnetic recording medium

A magnetic recording medium is disclosed. The medium is comprised of a support having a magnetic layer coated thereon. The magnetic layer is comprised of ferromagnetic metal powder and a binder. The ferromagnetic metal powder has a specific surface area of 35 to 70 m.sup.2 /g, a saturation magnetization (.sigma..sub.s) of 120 to 160 emu/g and a metal content of 75 to 98 wt %. The magnetic recording medium has a high S/N ratio, particularly a high video S/N ratio and has stable magnetic properties.

An electrophotographic photosensitive layer comprising finely divided photoconductive powders and a resin binder comprising a mixture of an acrylic resin and an epoxy ester resin in a ratio by volume of the acrylic resin to the epoxy ester resin of about 10:90 to 70:30; and an electrophotographic marking method suitable for use on substrates subsequently machined comprising electrophotographically marking machining information on a coating film, forming on a support to be machined, of the electrophotographic photosensitive layer as defined above and hardening the coating film.

Electrophotographic photosensitive layer and marking method

Electronic-photography light-sensitive material provided with a light-sensitive material layer suitable for rendering of continuous gradation of tones.

Method of treating photoconductive zinc oxide

A liquid developer for electrophotography is disclosed which comprises toner particles, a regulating agent composed of a copolymer of a half-alkylamide of maleic acid and .alpha.-diisobutylene and an electric insulating carrier liquid and, if desired, an organic acid.

Liquid developer for electrophotography

A process for machining metal work comprising forming a marked-off image from an image-forming material on a surface of a metal work or on a recording layer provided on the surface of the metal work and subsequently machining the metal work by machine cutting and/or oil immersion electrospark machining on the basis of the marked-off image, and including applying a protective resin layer on the image-bearing surface of the metal work prior to any metal machining, the resin layer comprising a mixture of nitrocellulose and a methacrylic polymer in a weight ratio ranging from about 80:20 to 40:60 of the nitrocellulose to the methacrylic polymer and not hindering the viewing of the image, and the methacrylic polymer mainly comprising methyl methacrylate and having a glass transition temperature of higher than about 85.degree. C.

Method for machining metal work

A liquid developer composition is given whereby a mixture of pigment and resin is milled and washed prior to being dispersed in the carrier liquid.

Milled and polar solvent extracted liquid developer

Improved toner particles each comprising an intimate mixture of a photoconductive pigment and an insulating binder capable of transporting charge carriers when the charge carriers are injected therein from the pigment, the proportion of the total volume of the pigment in the toner particle being 2 to 30 volume percent of the toner particle and the insulating binder being substantially transparent to the light in the region of the spectrum to which the pigment is sensitive. The toner particle may have therein a core or cores of a material which is substantially transparent to the light in the spectral-sensitive region of the pigment. The toner particles have improved surface durability and can be used repeatedly.

Photoconductive toners which include photoconductive pigment particles

A photoconductive binder layer comprising a particulate mixture of photosensitive titanium dioxide and photosensitive cadmium pigment dispersed in an insulating resin binder.

Photosensitive binder layer for xerography containing titanium oxide and

A liquid developer composition is given whereby a dispersion comprising a milled mixture of graft pigment and alkyd resin is dispersed in an insulating liquid.

Milled liquid developer

A liquid electrophotographic developer and processes for employing same are disclosed. The developer is composed of a liquid carrier, pigment, and a resin which results in a developed image that is abrasion resistant. The developer contains from 5 to 70% of the resin component which comprises an epoxy-ester.

Electrophotographic imaging process employing epoxy-ester containing

A photosensitive member for electrophotographic use having a photosensitive binder layer comprising zinc oxide and titanium dioxide photoconductive particles blended in a ratio of about 50:50 to 80:20 by weight and homogeneously dispersed into a film forming insulating resin binder, the particles having an average size of about 0.05 micron to 1.0 micron and the zinc oxide and titanium dioxide particles diffusing in light sensitivity by a factor of more than about 1.2 based on a gray filtered mean daylight source.

Growing community of inventors

Asaka, Japan

Hajime Miyatuka