US 5,852,757 AGranted

Electrophotographic image forming apparatus having a device for recovering residual toner

AssigneeFujitsu Limited

InventorsToshio Tooda, Yoshio Yamaguchi, Nobuo Kuwabara, Mituru Sato, Haruyasu Watanabe, Akira Nagahara, Sachio Sasaki, Yoshiya Ishiyama, Hiroshi Kera, Masanori Nishido, Hisashi Hanzawa

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Abstract

An electrophotographic image forming apparatus including a toner circulating mechanism for recovering a residual toner scraped from a photosensitive drum to a developing device. The developing device includes a housing for defining a toner chamber, a developing roller rotatably mounted in the housing, an agitator rotatably mounted in the housing and provided in the toner chamber, and a partition member mounted to the housing to define a carrier chamber between the partition member and the developing roller. The toner circulating mechanism directly returns the residual toner scraped from the photosensitive drum to the toner chamber in the developing device. The toner chamber may contain a foreign matter removing device. The partition member may have various shapes.

Claims18

Dependent claims

An electrophotographic image forming apparatus comprising:

an electrostatic latent image carrying member;
charging means for uniformly charging said carrying member;
means for exposing said carrying member to light according to image information to form an electrostatic latent image on said carrying member;
developing means for developing said electrostatic latent image to form a toner image on said carrying member, said developing means including a housing for defining a toner chamber, a developing roller rotatably mounted to said housing, an agitator rotatably mounted to said housing and provided in said toner chamber, and a partition member mounted to said housing to define a carrier chamber between said partition member and said developing roller, wherein said housing has a toner supply opening adapted to supply toner from outside said housing and communicating with said toner chamber, and said developing means further comprises a foreign matter removing means provided so as to cover said toner supply opening, wherein said developing means further comprises a vibrating means for vibrating said foreign matter removing means;
transferring means for transferring said toner image from said carrying member to a sheet of paper;
means for fixing said toner image transferred to said paper;
cleaning means for cleaning a residual toner from said carrying member;
and
circulating means for recovering said residual toner cleaned from said carrying member by said cleaning means to said toner chamber in said developing means.

6 more elements

An electrophotographic image forming apparatus comprising:

an electrostatic latent image carrying member;
charging means for uniformly charging said carrying member;
means for exposing said carrying member to light according to image information to form an electrostatic latent image on said carrying member;
developing means for developing said electrostatic latent image to form a toner image on said carrying member, said developing means including a housing for defining a toner chamber, a developing roller rotatably mounted to said housing, an agitator rotatably mounted to said housing and provided in said toner chamber, and a partition member mounted to said housing to define a carrier chamber between said partition member and said developing roller;
transferring means for transferring said toner image from said carrying member to a sheet of paper;
means for fixing said toner image transferred to said paper;
cleaning means for cleaning a residual toner from said carrying member;
and
circulating means for recovering said residual toner cleaned from said carrying member by said cleaning means to said toner chamber in said developing means, said circulating means including a rear plate disposed in said housing for defining a toner recovery chamber, said rear plate having an opening formed at a substantially transversely central portion thereof allowing communication between said toner recovery chamber and said toner chamber therethrough, and a tube having one end connected to said cleaning means and another end connected to said toner recovery chamber.

6 more elements

Dependencies are inferred from the claim text.