Fuji Photo Film Company, Limited

Sugihiko Tada

Takahito Miyoshi

Yasuo Nishikawa

Hirokazu Saito

Masaaki Fujiyama

Hiroshi Ogawa

Tsutomu Okita

Katsumi Ryoke

Masami Suzuki

Eiichi Tadokoro

Nobutaka Yamaguchi

Toshimitu Okutu

Masatoshi Sugiyama

Kenichi Masuyama

Takanori Sato

Jun Arakawa

Masahiro Utumi

Yuzo Inukai

Kazuhiko Yanagihara

Kazutoshi Inada

Masahiro Utsumi

Kazuo Irie

Hideaki Suzuki

Yasuo Nishigaki

Setsuo Nakai

A method of producing a silver halide photographic emulsion in which a silver ion concentration in precipitation of a silver halide emulsion in a precipitation bath is controlled, wherein a precipitation bath in which stirring is conducted rapidly and uniformly, and crystal formation and crystal growth are uniformly performed is used, the method comprises the steps of: in a start period of precipitation, quantitavely adding a silver nitrate solution and a halogen salt solution at a constant ratio flow rate; when an E value reaches a designated E value region in the vicinity of a preset target E value, starting a control of an adding rate of the halogen salt solution by using a controller which has an operation period equal to or shorter than 1 sec.; and after holding a tuning parameter of a proportional, integral and differential (PID) action controller to a minimum response level, conducting a control in which the tuning parameter is switched to an optimum control tuning parameter which corresponds to the preset target value and a solute rate of silver/halogen ions to be added.

Apparatus for measuring a silver or halogen ion concentration

A method of producing a silver halide photographic emulsion in which a silver ion concentration in precipitation of a silver halide emulsion in a precipitation bath is controlled, wherein a precipitation bath in which stirring is conducted rapidly and uniformly, and crystal formation and crystal growth are uniformly performed is used, the method comprises the steps of: in a start period of precipitation, quantitavely adding a silver nitrate solution and a halogen salt solution at a constant ratio flow rate; when an E.sub.Ag value reaches a designated E.sub.Ag value region in the vicinity of a preset target E.sub.Ag value, starting a control of an adding rate of the halogen salt solution by using a controller which has an operation period equal to or shorter than 1 sec.; and after holding a tuning parameter of a proportional, integral and differential (PID) action controller to a minimum response level, conducting a control in which the tuning parameter is switched to an optimum control tuning parameter which corresponds to the preset target value and a solute rate of silver/halogen ions to be added.

Method of producing a silver halide photographic emulsion, apparatus for

A method of manufacturing a photographic printing paper support wherein a composition consisting essentially of polyethylene terephthalate is hot extruded so as to cover at least one surface of the raw paper, this method being characterized in that after a hot extruded film of the aforesaid composition is discharged onto the raw paper on the nip roll, it is pressed in contact with the chilled roll.

Method of manufacturing a photographic printing paper support

Disclosed is a photographic printing paper comprising a raw paper which has on the emulsion side a resin coating constituted of polyethylene terephthalate or a resin blend of polyethylene terephthalate and another resin and titanium oxide grains dispersed therein and on the back side a resin coating constituted of the same polyethylene terephthalate or resin blend as used in the resin coating on the emulsion side and inorganic grains having an average grain size of from 1.5 to 12 .mu.m.

Photographic printing paper support

A photographic printing paper support wherein one side of the raw paper is covered by a composition containing titanium oxide dispersed in polyethylene terephthalate resin or a mixture of polyethylene terephthalate and another resin, and the other side is covered by a composition containing calcium carbonate dispersed in polyethylene terephthalate resin or a mixture of polyethylene terephthalate with another resin, which can provide an excellent photographic paper having good water resistance, whightness and gloss is disclosed.

A process for producing a magnetic recording medium is disclosed. The process comprises coating a magnetic coating composition comprising a ferromagnetic powder, a binder, and an organic solvent on either a non-magnetic support or a roller or band having a mirror surface to form a magnetic layer on the non-magnetic support or the roller or band, respectively, drying the magnetic layer so as to have a solvent content of from 0.05 to 10% by weight, contacting the magnetic layer on the support or the roller or band with a roller or band having a mirror surface or a non-magnetic support, respectively, and separating the magnetic layer from the roller or band. The resulting magnetic recording medium has smooth surface, high electromagnetic properties, and good durability.

Process for producing a magnetic recording medium

A magnetic coating composition comprising a binder dissolved in a solvent and magnetic grains dispersed therein is applied onto a surface of a non-magnetic substrate continuously moved. The coating film thus overlaid on the non-magnetic substrate is subjected to a preliminary orientation step for orientating the magnetic grains in the coating film, and then to a preliminary drying step. A final orientation step is then conducted while intermediate drying is carried out. Thereafter, final drying is effected.

Method of making magnetic recording medium

A method for producing a magnetic recording medium is disclosed. The method involves providing a ferromagnetic coating layer on a non-magnetic support base to produce a coated base. The coated base is then subjected to an atmosphere having a RH of 60% or more, prior to or during a subsequent calendering treatment. The recording medium produced has excellent surface smoothness and improved electromagnetic properties. The method is advantageous in that a substantially long period of time may pass between the coating of the ferromagnetic layer on the support and the calendering treatment without having undesirable effects on the magnetic recording medium produced.

Method of preparing a magnetic recording medium with a calendering

A process for reclaiming a photographic coupler from an aqueous oil-in-water emulsion of a coupler solvent oil having an oil-soluble photographic coupler dissolved therein comprising separating the coupler solvent oil containing the photographic coupler dissolved therein from the aqueous oil-in-water emulsion, and subjecting the separated coupler solvent oil containing the photographic coupler dissolved therein to a high vacuum molecular distillation whereby only the coupler solvent oil is removed as a distillate.

Oil soluble photographic coupler reclamation process

A process for preparing a coupler dispersion comprising contacting a coupler dispersion containing an auxiliary solvent with an auxiliary solvent carrying fluid medium through a hydrophobic macroporous film made of polytetrafluroethylene or polypropylene.

Process for the preparation of coupler dispersions

Apparatus for continuously removing a film coating material from a photosensitive base comprising continuously removing a photosensitive emulsion from a film base, which is coated with an emulsion, by the contact reaction of a removing liquid with the emulsion, continuously and automatically washing and recovering the emulsion-removed film base, and continuously and automatically concentrating and recovering the silver halide which is contained; also, in the suspension.

Apparatus for continuously removing film coating materials from film

Crude hydroquinone containing impurities is purified in a sublimation purification apparatus where the crude hydroquinone is introduced into a stirred and fluidized bed, a carrier gas which is inert to the hydroquinone is passed therethrough, and the temperature therein is kept at about 110.degree.-170.degree.C whereby crude hydroquinone is sublimed, and thereafter a mixed gas consisting of the sublimed vapor and the carrier gas is introduced into a condenser at a temperature at about 25.degree.-90.degree.C whereby the hydroquinone only is fractionally solidified. After the sublimation purification, hydroquinone of high purity can be collected.

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Shizuoka, Japan

Sugihiko Tada