Hitachi Koki Co., Ltd.

Ricoh Printing Systems, Ltd.

Hiroshi Ueno

Kunitomo Takahashi

Isao Nakajima

Yasuyuki Tsuji

Tsukasa Onose

Shuuho Yokokawa

Shuho Yokokawa

Youji Hirose

Yoshio Ogura

Koji Doi

Isao Watanabe

Youichi Takeuchi

Shigenori Yaguchi

Sho Sawahata

Ken Onodera

Toshitaka Ogawa

Yasuo Kikuchi

Tetsuya Ohba

Ryuuichi Shimizu

Koutarou Yamada

Koutaro Yamada

Katuhiro Shinohara

Kouhei Katayama

Kouji Doi

Susumu Saito

Keiji Kataoka

Yukio Otome

Shigenobu Katagiri

Minoru Seino

Osamu Namikawa

Muneyoshi Akai

Satoshi Aita

Hidenori Iwanaga

Katsumi Ishizawa

Tsukasa Ogawa

Takao Chikuzenya

Hiroshi Hakuta

Hiroyuki Ogawa

Katsuhiro Shinohara

Minoru Murase

Kazuo Takano

Syou Sawahata

Hisashi Nakajima

Takehiro Honda

Yuuji Meguro

Koutara Yamada

An electrophotographic toner for visualizing an electrostatic latent image formed by an electrophotographic process, an electrostatic printing process, an electrostatic recording process, etc., which is produced in consideration of the environment and safety. The electrophotographic toner includes a fixing resin and a colorant. The electrophotographic toner is a black toner using a titanium compound containing no carbon black as the colorant. The electrophotographic toner may be an electrophotographic two-component black toner using magnetic iron oxide containing no carbon black as the colorant.

Electrophotographic toner

An exposure device for an electrophotographic apparatus including one or more laser light sources which expose an image carrier in accordance with a print information signal supplied from an external information processing apparatus, a resolution switching lens, and a switching unit to switch over a low resolution and a high resolution by inserting and extracting the resolution switching lens into and from a laser optical path. Preferably, a light emission time of each of the laser light sources with respect to the print information signal is changeable.

Exposure device for an electrophotographic apparatus

Electrophotographic toner and image-forming system

In a printing system including first image forming means (A) for forming a first image on a recording medium () based on first image information, fixing means (and) for subjecting the recording medium bearing the first image thereon to at least heating operation so as to fix the first image onto the recording medium, and second image forming means (B) for forming a second image on the recording medium, which has passed through the fixing means, based on second image information, there is provided correcting means for correcting the second image information based on a quantity of heat shrinkage of the recording medium generated by the heating operation in the fixing means.

Printing system and printing method

By providing a printing density controller for changing a printing density in a range from a dropout color to non-dropout color, an electrophotographic printing apparatus can conduct the light and shade adjustment of the printing density in a broad range, and also cope with the dropout color printing.

Electrophotographic apparatus having a printing density controller for dropout and non-dropout color

A release agent supplying member (21) is formed by release agent discharge portions (21a) for discharging release agent, and liquid level uniforming portions (21b) for uniforming a liquid level of the release agent discharged from the release agent discharge portions before supplying the release agent discharged from the release agent discharge portions to a subject to be coated.

Release agent supplying member, release agent supplying apparatus and

In a fixing apparatus for an electrophotographic apparatus which comprises a suction apparatus (14) for attracting a rear surface of recording material (6) which continues longitudinally and holds a toner image on a major surface thereof, a preheater (10) for preheating the recording material while adhering the recording material to the preheater by attracting force of the suction apparatus, and a pair of fixing rollers (11) formed by a heat roller and a pressure roller urged to each other, wherein the recording material is sandwiched and carried while being heated and pressurized by the heat roller and the pressure roller at a pressing portion therebetween thereby to fix the toner image on the major surface of the recording material, the fixing apparatus further comprises a recording material lifting apparatus (15) having a projection member (15a) movable relative to the surface of the preheater.

Fixing apparatus and fixing method for electrophotographic apparatus

Preheating temperature of a preheating plate provided on the front side of a fixing unit can be changed using a temperature controller. In a case where a printing system to print images on both sides of a print member is constructed by arranging two electrophotographic printing apparatuses in dependent relationship, the preheating temperature of the preheating plate in the electrophotographic printing apparatus in the second stage is changed to a low temperature to prevent the toner image fixed in the electrophotographic printing apparatus in the first stage from softening.

Preheating controller for a two-stage electrophotographic printing system

When a developing agent prepared to have a preset toner density is loaded in a developing unit, a comparing reference level for controlling the toner density in the developing agent is changed to a value higher than the preset value in the initial stage of operation and fresh toner is supplied to the developing agent so that the toner density of the developing agent is increased in comparison to the reference level. Thereby, the developed density is prevented from decreasing due to an excess amount of friction charge of the toner.

Developing unit for electro-photographic apparatus

An electrophotographic apparatus system or an electrophotographic apparatus provided according to the present invention has the discrepancy of printing speed between tandem and single printing removed. The electrophotographic apparatus system or the electrophotographic apparatus is provided with printing speed changeover means 23a, 23b, 24 not only to select a printing speed applicable for the case where printing is effected with a plurality of electrophotographic apparatus A, B operatively linked together and another printing speed serviceable for the case where printing is implemented with each of plural electrophotographic apparatus put into separate run independently of one another, but also to shift the printing speeds from one to another, whereby the electrophotographic apparatus system or the electrophotographic apparatus may provide normal performance in each of the respective formations of printing.

Electrophotographic printing system including a plurality of

A toner recovering device for an electrophotographic apparatus, which includes: a dust collector connected to a device for cleaning untransferred toner remaining on a photosensitive body; a toner recovering filter having an inlet port for introducing an air-toner mixture from the dust collector side and an exhaust port for filtering the air-toner mixture and discharging the air from which the toner has been removed; a filter mounting section for mounting the toner recovering filter; a joint mechanism having a joint and a hose member, one end of the hose member capable of being connected to the dust collector and other end thereof being joint, the joint being disposed at the inlet port, the joint mechanism being arranged in the filter mounting section in such a manner as to be opened and closed; a detector for sensing that the toner recovering filter has been mounted or not onto the filter mounting section; and a pulling member for coupling the inlet port of the toner recovering filter to the joint in synchronism with an operation of mounting the toner recovering filter onto the filter mounting section.

Toner recovering device for electrophotographic apparatus and toner

A developing device in an electrophotographic apparatus, wherein a pole c.sub.1 which is a delivering magnetic pole of the second developing roll for delivering the developer to the first developing roll and a pole d.sub.1 which is a receiving magnetic pole of the second developing roll for receiving the developer from the first developing roll are set so as to be the same in polarity, whereas a pole a.sub.2 which is a receiving magnetic pole of the first developing roll for receiving the developer from the second developing roll and a pole g.sub.2 which is a delivering magnetic pole of the first developing roll for delivering the developer to the second developing roll are set to be equal in polarity, wherein each of an angle between the poles c.sub.1 and d.sub.1 and an angle between the poles a.sub.2 and g.sub.2 is set so as to be in a range of from 70.degree. to 120.degree., and wherein the magnetic flux density of each of a reaction pole induced between the poles c.sub.1 and d.sub.1 and a reaction pole induced between the poles a.sub.2 and g.sub.2 is set so as to be less than or equal to 0.015 tesla.

Developing device in electrophotographic apparatus including developing

Regulating parts E, F, of a developing agent regulating member 6, are arranged opposite to a photosensitive drum 7 with respect to a line connecting the centers of a developing roll 5 having a sleeve rotating in the direction of a and a developing roll 8 having a sleeve rotating in the direction of b. Holding members 10 which are slidable on the side plate of a developing apparatus are respectively provided at both ends of the developing agent regulating member. Developing agent is supplied from developing roll 5 to developing roll 8 through a back surface of the developing agent regulating member 6.

Developing apparatus having developer regulating member

A developing unit for an electrophotographic apparatus comprises a photosensitive body for forming a latent image thereon, a developing roll utilizing two-component developer containing toner and carrier to develop the latent image formed on the photosensitive body, a recovery roll, provided downstream of the developing roll, for recovering carrier from a surface of the photosensitive body, and at least one recess formed in an inner surface of the developing unit which is confronted with an outer cylindrical surface of the recovery roll, in such a manner that air pressure formed in the recess prevents the developer from scattering out of the developing unit.

Developing unit for an electrophotographic apparatus

A developing device for use in an electrophotographic apparatus includes a casing for storing a developer including a toner and a carrier therein; a photosensitive drum having a surface on which an electrostatic latent image is formed; a carrying magnetic roll for drawing up the developer stored in said casing; a developing magnetic roll for forming a magnetic brush out of the developer fed by the carrying magnetic roll to develop the electrostatic latent image; and a developer mixing chamber including an impeller interposed between the carrying and developing magnetic rolls, for mixing the toner and carrier contained in the developer with each other, which is drawn up by the carrying magnetic roll, to supply the mixed developer to the developing magnetic roll.

Developing device having a developer mixing chamber for use in

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Ibaraki, Japan

Hiroshi Ueno