Electrophotography – Image formation – Development
Reexamination Certificate
2001-02-27
2002-10-15
Chen, Sophia S. (Department: 2852)
Electrophotography
Image formation
Development
C399S098000, C399S149000
Reexamination Certificate
active
06466758
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a developing apparatus for developing a latent image on an image bearing member, which is used with an image forming apparatus of electrophotographic type or electrostatic recording type such as a copying machine, a printer and the like.
2. Related Background Art
In image recording apparatuses of a transfer type, after transferring, residual developer (toner) remaining on a photosensitive member (image bearing member) is removed from a surface of the photosensitive member by a cleaner (cleaning apparatus) as waste toner. It is desirable that the waste toner does not escape out of the apparatus from the viewpoint of protection of environment.
To this end, there has been proposed an image recording apparatus having a toner recycle system (or toner recycle process) in which a cleaner is omitted, and, after the transferring, residual toner remaining on a photosensitive member is removed by “cleaning simultaneously with developing” and the removed waste toner is collected in a developing apparatus and is re-used.
The cleaning simultaneous with developing is referred to as a method in which the residual toner remaining on the photosensitive member after the transferring is collected by fog removal bias (having fog removal potential difference of Vback which is potential difference between Av voltage applied to the developing apparatus and surface potential on the photosensitive member) in the subsequent developing process.
According to this method, since the residual toner is collected in the developing apparatus and is re-used in the subsequent process and so on, the waste toner can be eliminated and maintenance can be reduced. Further, since there is no cleaner, space can be saved, thereby making the image recording apparatus substantially more compact.
However, the above-mentioned cleanerless system has the following problem.
That is to say, when the cleanerless system is used, since the toner is recycled without providing the cleaner, foreign matter such as paper powder from a recording paper will enter into the developing device, thereby causing poor image formation.
Such paper powder enters into the developing device during the image recording, which results in reduction of image density and deterioration of uniformity of the image recording having intermediate density.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a developing apparatus which can prevent reduction in image density due to paper powder.
Another object of the present invention is to provide a developing apparatus which can separate foreign matter from toner.
A further object of the present invention is to provide a developing apparatus comprising a developing container, a toner carrying member provided at an opening portion of the developing container and adapted to carry toner, and a toner container disposed adjacent to the developing container and adapted to replenish the developing container with the toner, wherein the toner container has a space portion which disposed below the toner carrying member and which is not substantially replenished with the toner.
The other objects and features of the present invention will be apparent from the following detailed explanation referring to the accompanying drawings.
REFERENCES:
patent: 5283615 (1994-02-01), Yokoyama et al.
patent: 5561506 (1996-10-01), Kasahara
patent: 5802430 (1998-09-01), Wada
patent: 5970279 (1999-10-01), Sakaizawa et al.
patent: 58-072969 (1983-05-01), None
patent: 61-228478 (1986-10-01), None
patent: 07-104578 (1995-04-01), None
patent: 07-152248 (1995-06-01), None
Chigono Yasunori
Hirabayashi Jun
Ishiyama Harumi
Canon Kabushiki Kaisha
Chen Sophia S.
Fitzpatrick ,Cella, Harper & Scinto
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