Electrophotography – Image formation – Fixing
Reexamination Certificate
1999-11-30
2001-02-27
Chen, Sophia S. (Department: 2852)
Electrophotography
Image formation
Fixing
C219S216000, C399S307000, C399S325000, C492S056000
Reexamination Certificate
active
06195526
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a fixation roller for a liquid electrophotographic printer contacting a transfer roller which transfers an image to a sheet of paper and a transferring apparatus adopting the same.
2. Description of the Related Art
In general, a liquid electrophotographic printer such as a laser printer or a copier uses developer which is a mixture of powdered toner and liquid carrier. Referring to
FIG. 1
, a conventional liquid electrophotographic printer includes a photoreceptor web
10
circulating by being supported by a plurality of guide rollers
11
, one or more developing unit
14
and a transferring unit
17
. The transferring unit
17
includes a transfer roller
15
and a fixation roller
16
.
The photoreceptor web
10
is charged by a charger
12
to a predetermined electric potential. A laser scanning unit
13
installed at the developing unit
14
emits a beam onto the surface of the photoreceptor web
10
. Accordingly, the electric potential of the photoreceptor web
10
changes and an electrostatic latent image is formed thereon. The developing unit
14
supplies developer to the surface of the photoreceptor web
10
to develop the electrostatic latent image and residual developer is collected. As the photoreceptor web
10
circulates, the developed image formed on the surface of the photoreceptor web
10
is transferred to the transfer roller
15
due to a difference in surface energy and then printed on a sheet of paper P passing between the transfer roller
15
and the fixation roller
16
.
Here, the fixation roller
16
is driven while pressing the transferring roller
15
with a predetermined pressure, and a rubber layer is provided around the outer circumference thereof.
However, when the conventional liquid electrophotographic printer is used for a long time, foreign materials such as remaining toner particles adhering to the surface of the transfer roller
15
are moved to the fixation roller
16
and then accumulated thereon. The contamination of the fixation roller
16
increases the surface energy of the fixation roller
16
. Thus, the paper P passing between the transfer roller
15
and the fixation roller
16
is bent or folded toward the fixation roller
16
.
SUMMARY OF THE INVENTION
To solve the above problem, it is an objective of the present invention to provide a fixation roller for a liquid electrophotographic printer having an improved structure so that the fixation roller is prevented from being contaminated, and a transferring apparatus adopting the same.
Accordingly, to achieve the above objective, there is provided a fixation roller for a liquid electrophotographic printer rotating in contact with a transfer roller transferring an image developed on a photoreceptor web to a sheet of paper, in which the fixation roller comprises a body made of metal, an elastic rubber layer formed on the outer circumferential surface of the body, and silicon oil included in the rubber layer to come out to the surface of the rubber layer at a high temperature during printing and encompass the surface of the rubber layer.
It is preferable in the present invention that the silicon oil is made by mixing with rubber which is used as a material for the rubber layer.
Also, it is preferable in the present invention that the amount of the silicon oil added is about 2-3 wt % with respect to rubber.
To achieve another aspect of the above objective, there is provided a transferring apparatus including a transfer roller for transferring an image developed on a photoreceptor web to a sheet of paper and a fixation roller rotating in contact with the transfer roller, in which the fixation roller comprises a body made of metal, an elastic rubber layer formed on the outer circumferential surface of the body, and a silicon oil layer formed by coating the outer circumferential surface of the rubber layer to a predetermined thickness.
It is preferable in the present invention that the transferring apparatus further comprises a means for supplying silicon oil to the rubber layer.
Also, it is preferable in the present invention that the means for supplying silicon oil comprises an oil supply roller installed to be rotated in contact with the rubber layer of the fixation roller and a tank for supplying silicon oil to the oil supply roller.
Also, it is preferable in the present invention that the oil supply roller is made of stainless steel or urethane.
REFERENCES:
patent: 4231653 (1980-11-01), Nagahara et al.
patent: 4976877 (1990-12-01), Agostinelli et al.
patent: 5123151 (1992-06-01), Uehara et al.
patent: 5650253 (1997-07-01), Baker et al.
patent: 5966578 (1999-10-01), Soutome et al.
patent: 6009300 (1999-12-01), Kagawa et al.
patent: 62-044754 (1987-02-01), None
patent: 1-031183 (1989-02-01), None
Lee Jin-Soo
Rhee Chang-Soo
Chen Sophia S.
Samsung Electronics Co,. Ltd.
Sughrue, Minn, Zinn, Macpeak & Seas, PLLC
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