Developing apparatus

Details Developing apparatus Developing apparatus

2001-01-18

2002-10-29

Ngo, Hoang (Department: 2852)

Electrophotography

Having particular structure

Modular or displaceable

C399S090000, C399S265000, C399S270000, C399S271000

Reexamination Certificate

active

06473578

ABSTRACT:

FIELD OF THE INVENTION AND RELATED ART
The present invention relates to such a developing apparatus that develops an electrostatic image formed on an image bearing member, with the use of developer. This type of a developing apparatus is preferably used as a developing apparatus for an image forming apparatus such as a copying machine, printer, and the like.
As the cumulative usage time of an electrophotographic image forming apparatus reaches a certain point, it becomes necessary to replace the photosensitive drum, to replenish or replace developer, and/or to adjust, clean, and/or replace the charging device, cleaning means container, and the like. These maintenance operations have been generally difficult, except for service personnel with professional knowledge.
In order to eliminate this inconvenience, a process cartridge, or a cartridge in which an image bearing member (photosensitive drum), and a single or plural image processing means, for example, a developing apparatus, a cleaning apparatus, and the like, are integrally placed, has been commercialized.
As a result, it has become simple for users themselves to maintain an image forming apparatus, or replace the aforementioned processing means as it becomes necessary for an image forming apparatus to be maintained. Therefore, it has become easy and inexpensive to obtain high quality images.
The aforementioned developing apparatus, or one of the components which a process cartridge comprises, has a development roller as a developer bearing member which is placed in a manner to oppose a photosensitive drum as an image bearing member. The development roller has a development sleeve, and a magnetic roll. The magnetic roll is nonrotational and placed in the development sleeve, and the development sleeve is rotated about the magnetic roll. In order to transfer the toner uniformly borne on the peripheral surfaces of the development sleeve, onto an electrostatic latent image on the peripheral surfaces of the photosensitive drum, bias is applied to the development sleeve. As for a means for applying bias to the development sleeve, a method illustrated in
FIG. 12
has been proposed. According to this method, a flange
102
formed of electrically conductive material is fixed to one of the longitudinal ends of a development sleeve
101
, and an electrode
105
in the form of a compression coil spring is fitted around the flange
102
in a manner to allow electricity to flow between the two components. One end of the electrode
105
is attached to the housing
104
of a developing apparatus so that, as the developing apparatus is mounted in the main assembly of an image forming apparatus, the electrode
105
is placed in contact with an electrical contact electrically connected to a power supply provided on the main assembly side.
As for a means for supporting a magnetic roll
103
, the housing
104
of the developing apparatus is provided with a positioning hole
104
a
, the axial line of which coincides with that of the development sleeve
101
, and in which the smaller diameter portion
103
a
of the magnetic roll
103
is fitted to dictate the distance between the peripheral surfaces of the magnetic roll
103
and development sleeve
101
. However, a much simpler magnetic roll supporting method than the above described one has been desired.
In the case of the above described magnetic roll supporting method, the electrode
105
or flange
102
rotates with the development sleeve
101
which sliding on the contact on the main assembly side. Therefore, it is a common practice to coat the contact areas of the electrode
105
and contact on the main assembly side. This contact area is desired to be as small as possible so that the interface in which the two components slide against each other becomes as small as possible.
In order to stabilize the contact pressure between the electrode
105
and contact on the main assembly side, it is desirable to reduce the spring constant of the elastic contact (compression coil spring which constitutes electrode
105
), so that the amount of flexing of the electric contact increases. For this purpose, it, s necessary to provide the aforementioned developing apparatus with an internal space long in terms of the longitudinal direction of the developing apparatus.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a developing apparatus, the sliding contact of which is smaller than a conventional one.
Another object of the present invention is to provide a developing apparatus, the sliding contact of which is more reliable than a conventional one.
Another object of the present invention is to provide a developing apparatus, the magnetic roll of which is positioned with a higher degree of accuracy than in the conventional one.
Another object of the present invention is to provide a developing apparatus, the spacial efficiency of which in terms of the longitudinal direction of the developing apparatus is superior to that of the conventional one.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.


REFERENCES:
patent: 4708455 (1987-11-01), Kubota et al.
patent: 4872418 (1989-10-01), Yoshikawa et al.
patent: 5272505 (1993-12-01), Shishido et al.
patent: 5283619 (1994-02-01), Nomura et al.
patent: 5606722 (1997-02-01), Hart et al.
patent: 5634175 (1997-05-01), Michlin et al.
patent: 5655181 (1997-08-01), Chadani et al.
patent: 5682587 (1997-10-01), Higeta et al.
patent: 5701562 (1997-12-01), Araki et al.
patent: 5708925 (1998-01-01), Kobayashi et al.
patent: 5739900 (1998-04-01), Isobe
patent: 5761584 (1998-06-01), Tsuda et al.
patent: 5768658 (1998-06-01), Watanabe et al.
patent: 5802431 (1998-09-01), Nagashima et al.
patent: 5815782 (1998-09-01), Yokomori et al.
patent: 5822654 (1998-10-01), Damji et al.
patent: 5832343 (1998-11-01), Kobayashi et al.
patent: 6151465 (2000-11-01), Toba et al.
patent: 0 549 400 (1993-06-01), None
patent: 0 754 984 (1997-01-01), None
U.S. patent application Ser. No. 09/559.144, filed Apr. 27, 2000.
U.S. patent application Ser. No. 09/559,145, filed Apr. 27, 2000.
U.S. patent applicatin Ser. No. 09/050,931, filed Mar. 31, 1998.
U.S. patent application Ser. No. 09/167,723, filed Oct. 07, 1998.

Affiliated with

Also associated with

Rating

Developing apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Developing apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Developing apparatus will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2994806