Electrophotography – Machine operation – Electrical connection
Reexamination Certificate
1999-05-24
2001-08-14
Chen, Sophia S. (Department: 2852)
Electrophotography
Machine operation
Electrical connection
C399S111000
Reexamination Certificate
active
06275668
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a developing device and a process cartridge which are detachably mountable to an electrophotographic image forming apparatus, and an electrical contact part for the same.
An electrophotographic image forming apparatus is an apparatus that forms an image on a recording material using an electrophotographic image forming process, and includes an electrophotographic copying machines, an electrophotographic printer (LED printer, a laser beam printer or the like), an electrophotographic-printer-type facsimile machine and an electrophotographic-printer-type word processor.
A process cartridge is a cartridge that contains charging means, cleaning means, developing means and an electrophotographic photosensitive member as a unit, which is detachably mountable to a main assembly of an electrophotographic image forming apparatus. It may contain developing means and an electrophotographic photosensitive member and at least one of charging means and cleaning means. It may contain at least developing means and an electrophotographic photosensitive member.
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.
Referring first to
FIG. 28
, an example of a conventional developing device will be described.
In the conventional example, the image forming apparatus uses a process cartridge containing a unit process means, such as an electrophotographic photosensitive member, a charger, a developing device or a cleaning device. The process cartridge is detachably mountable to a main assembly of the image forming apparatus, so that maintenance or servicing is made easier.
The process cartridge has a developing apparatus for visualizing an electrostatic latent image formed on the photosensitive drum with a developer (toner). A developing roller unit is provided in the developing apparatus, and has a fixed magnet therein to carry the toner in the developing apparatus on a peripheral surface of a developing roller toward the photosensitive drum.
As shown in
FIG. 28
, the developing roller unit comprises a cylindrical developing roller
10
d
rotatable in a predetermined direction, and a fixed magnet
10
c
disposed in the developing roller
10
d.
The opposite ends are fixed to holders
14
a,
14
b
fixed to the main assembly of the developing device. The developing roller
10
d
and the fixed magnet
10
c
are disposed with a small gap therebetween. To the opposite ends of the developing roller
10
d,
flanges
12
a,
12
b
are fixed by press-fitting or bonding. The flanges
12
a,
12
b
are rotatably supported on the developing device by bearing members
23
a,
23
b
as supporting members.
In the flange
12
a,
a sleeve electrode (compression coil spring)
25
is provided. A fixed portion
25
a
at an end of the sleeve electrode
25
is press-fitted to contact the inside of the flange
12
a
, and is fixed to the flange
12
a.
The portion other than the fixed portion
25
a
is not confined on the flange
12
a,
so that resiliency is provided. The contact portion
25
b
at the other end of the sleeve electrode
25
contacts to the electrode plate
14
c
fixed to the holder
14
a
by the resiliency, and the contact surface is coated with electroconductive grease. The electrode plate
14
c
is electrically connected to a voltage source in the main assembly of the image forming apparatus to accomplish electric bias voltage supply to the developed roller
10
d.
By a sliding reference between the contact portion
25
b
of the sleeve electrode
25
and the electrode plate
14
c,
a force is applied in the direction of reduction of the diameter of the sleeve electrode
25
, by which the press-fitting of the fixed portion
25
a
is eased. By this, the sleeve electrode
25
is liable to disengage from the flange
12
a.
In order to prevent this, the direction of winding of the sleeve electrode
25
is determined so that contact portion
25
b
of the sleeve electrode
25
and the electrode plate
14
c
are contacted counterdirectionally. By doing so, the sliding resistance leads to an increase in the coil diameter of the sleeve electrode
25
.
However, the fixed portion
25
a
of the sleeve electrode
25
is in the flange
12
a.
Therefore, during the assembling in a plant, the visual inspection is performed as to the insertion and engagement of the sleeve electrode
25
with the flange. Therefore, it has been necessary for the inspector to manually pull the sleeve electrode
25
from the flange
12
a
to confirm whether the engagement is firm enough or not.
The sleeve electrode
25
is fixed to the inside of the flange
12
a.
Then, a space has to be provided for the sleeve electrode
25
by cutting a thickness of the flange
12
a.
This is disadvantageous from the standpoint of downsizing of the developing device.
SUMMARY OF THE INVENTION
Accordingly, it is a principle object of the present invention to provide an electrical contact part, a developing device and a process cartridge wherein the assembling operativity of an electrical contact part is improved.
It is another object of the present invention to provide an electrical contact part, a developing apparatus and a process cartridge wherein inspection after assembling of an electrical contact part is made easier. It is a further object of the present invention to provide an electrical contact part, a developing apparatus and a process cartridge wherein a developing bias can be stably supplied to a developing roller. According to an aspect of the present invention, there is provided and electrical contact part for supplying a bias voltage to a developing roller usable in a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus, which contains an electrophotographic photosensitive member, a developing roller for developing an electrostatic latent image formed on the electrophotographic photosensitive member, an electroconductive flange engaged to one end portion of the developing roller, a driving portion, provided at one end portion of the flange, for rotating the developing roller, the electrical contact part comprising (a) a connecting portion electrically connectable with a cartridge side electrode, which is provided in the process cartridge and which is connectable with a main assembly side electrode provided in the main assembly of the apparatus when the process cartridge is detachably mounted to the main assembly of the apparatus; and (b) a projected portion projected at a side opposite from a side at which the connecting portion is connectable to the cartridge side electrode and insertable to between the flange and the driving portion.
It is a further object of the present invention to provide a process cartridge detachably mountable to a main assembly of an electrophotographic image forming apparatus including (a) an electrophotographic photosensitive member; (b) a developing roller for developing the electrostatic latent image formed on the electrophotographic photosensitive member; (c) an electroconductive flange engaged with one end portion of the developing roller; (d) a driving portion, provided at one end portion of the flange, for rotating the developing roller; (e) a cartridge side electrode electrically connectable with a main assembly side electrode provided in the main assembly of the apparatus, when the process cartridge is detachably mounted to the main assembly of the apparatus; and (f) an electrical contact part for supplying a bias voltage to the developing roller, the electrical contact part including: (1) a connecting portion electrically connected to the cartridge-side electrode; (2) a projected portion projected at a side opposite from a side at which the connecting portion is connectable to the cartridge side electrode and insertable to between said flange and said driving portion.
REFERENCES:
paten
Canon Kabushiki Kaisha
Chen Sophia S.
Fitzpatrick ,Cella, Harper & Scinto
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