Charging apparatus with first and second charging members

Details Charging apparatus with first and second charging members Charging apparatus with first and second charging members

2000-02-11

2001-10-09

Royer, William J. (Department: 2852)

Electrophotography

Image formation

Charging

Reexamination Certificate

active

06301459

ABSTRACT:

FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a charging member for effecting charging using magnetic particles, a charging device and an image forming apparatus, which are particularly suitable to an electrophotographic copying machine or a printer of the same type.
As for a charging method in an electrophotographic apparatus, a corona charging type using a wire and a shield, has been mainly used. Recently, however, from the standpoint of environmental problems, a contact charging type has become widely used because of the small amount of ozone product produced due to the discharge. As one of such contact charging type, there is known a magnetic brush type wherein magnetic particles are contacted to a photosensitive member as a member to be charged. The charging member of magnetic brush type is provided with a magnet roller as a magnetic force production member, for example, a rotatable non-magnetic electrode sleeve around the outward of the magnet roller, and a layer of the magnetic particles attracted and supported on the surface of the electrode sleeve by the magnetic force of the magnet roller. In order to charge the photosensitive member, the layer of the magnetic particles is contacted to the photosensitive member, and the electrode sleeve is supplied with a voltage. In the magnetic brush type, the magnetic particles are pushed out to an end of the charging member in the longitudinal direction (generating line direction of the photosensitive member). In the end portion region, the magnetic brush is not always contacted to the photosensitive member, and therefore uniform charging is difficult. Therefore, the potential of the photosensitive member in the end portion region, is quite lower than that in the central portion region. For this reason, the potential of the electrode sleeve and the potential of the surface of the photosensitive member, are significantly different in the end portion region, with the result that the magnetic particles move to the photosensitive member from the charging member. If the magnetic particles are deposited on the photosensitive member, the amount of the magnetic particles on the photosensitive member gradually decreases which results in a charging defect. The charging defect leads to deterioration of the image, and the long term use is not possible with the magnetic brush type.
SUMMARY OF THE INVENTION
Accordingly, it is a principal object of the present invention to provide a charging member, a charging device and an image forming apparatus, wherein deposition of magnetic particles to the member to be charged from the charging member is effectively prevented.
It is another object of the present invention to provide a charging member, a charging device and an image forming apparatus, wherein proper image formation can be maintained for a long term.
These and other objects, features and advantages of the present invention will become more, apparent upon a consideration of the following invention taken in conjunction with the accompanying drawings.


REFERENCES:
patent: 5010370 (1991-04-01), Araya et al.
patent: 5084733 (1992-01-01), Katoh et al.
patent: 5235386 (1993-08-01), Yano et al.
patent: 5272505 (1993-12-01), Shishido et al.
patent: 5357323 (1994-10-01), Haneda et al.
patent: 5398102 (1995-03-01), Wada et al.
patent: 5432033 (1995-07-01), Asanae et al.
patent: 5446615 (1995-08-01), Matsumoto et al.
patent: 5450171 (1995-09-01), Demura et al.
patent: 5576805 (1996-11-01), Ishihara et al.
patent: 5596394 (1997-01-01), Nishiguchi et al.
patent: 5805962 (1998-09-01), Ko
patent: 0 035 745 A2 (1991-09-01), None
patent: 0 593 245 A1 (1994-04-01), None
patent: 0 598 483 A1 (1994-05-01), None
patent: 60-205550 (1985-10-01), None
patent: 60-205551 (1985-10-01), None
patent: 05-100544 (1993-04-01), None
patent: 51-00544 (1993-04-01), None
patent: 06-118770 (1994-04-01), None
patent: 06-110296 (1994-04-01), None
Patent Abstracts of Japan, vol. 010, No. 064 (P-436), Mar. 14, 1986, relating to JP 60-205550, published Oct. 17, 1985.
Patent Abstracts of Japan, vol. 17, No. 451 (P-1595), Aug. 18, 1993, relating to JP 51-00544, published Apr. 23, 1993.
Patent Abstracts of Japan, vol. 018, No. 405 (P-1778), Jul. 28, 1994, relating to JP 06-118770, published Apr. 28, 1994.

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