Hitachi Koki Co., Ltd.

Yoshio Ogura

Hiroshi Ueno

Yasuyuki Tsuji

Shuuho Yokokawa

Isao Nakajima

Tsukasa Onose

Kunitomo Takahashi

Youji Hirose

Isao Watanabe

Youichi Takeuchi

Koutaro Yamada

Kouji Doi

Yukio Otome

Muneyoshi Akai

Koutarou Yamada

Katuhiro Shinohara

Kouhei Katayama

Minoru Murase

Katsuhiro Shinohara

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

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

A toner density detection method for an electrophotographic apparatus in which driving of a rotary roll provided at an outlet of a special vessel is continued for a predetermined period of time (e.g., several seconds) after the operation of the electrophotographic apparatus is stopped. All or substantially all of the developing agent is thus exhausted or removed from the special vessel after the electrophotographic apparatus is stopped, so that the true permeability of the developing agent can be detected by a permeability sensor when the operation of the electrophotographic apparatus is restarted. As a result, the toner density of the developing agent can be controlled and kept normal, so that the printing quality can be stabilized.

Toner density detection method for electrophotographic apparatus

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Ibaraki, Japan

Yoshio Ogura