Electrophotography – Image formation – Photoconductive member
Reexamination Certificate
2002-07-02
2004-03-23
Goodrow, John (Department: 1756)
Electrophotography
Image formation
Photoconductive member
C430S056000
Reexamination Certificate
active
06711369
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of Korean Application No. 2002-10261, filed Feb. 26, 2002, in the Korean Industrial Property Office, the disclosure of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a photosensitive drum structure for an image forming apparatus using a photosensitive belt, and more particularly, to a photosensitive drum structure for an image forming apparatus used in an electrophotographic printer.
2. Description of the Related Art
In general, an electrophotographic printer such as a laser printer forms a latent electrostatic image on a photosensitive medium, develops the latent electrostatic image with a toner having a predetermined color, and transfers the developed toner image to a printing paper in order to obtain a desired image. The photosensitive medium is typically a photosensitive belt or a photosensitive drum.
FIG. 1
is a view of a portion of an image forming apparatus using a known photosensitive belt as a photosensitive medium. Referring to
FIG. 1
, the rotation path of a photosensitive belt
10
that travels a continuous path due to rollers
10
a
,
10
b
, and
10
c
includes an eraser
12
, a charger
14
, a laser scanning unit (LSU)
16
, and a plurality of developing units
18
a
,
18
b
,
18
c
, and
18
d
. The eraser
12
erases charges on the photosensitive belt
10
. The charger
14
charges the photosensitive belt
10
with a predetermined electric potential. The LSU
16
radiates light onto the photosensitive belt
10
to form a latent electrostatic image. The plurality of developing units
18
a
,
18
b
,
18
c
, and
18
d
are disposed in series along the travel direction of the photosensitive belt
10
and each develops the latent electrostatic image as a toner image with a different color. The developed toner image is transferred to a transfer belt
20
that circulates in contact with the photosensitive belt
10
.
However, in the above-described transfer method, the photosensitive belt
10
may move laterally outside of a transfer range of the image. Thus, a steering unit (not shown) is needed to adjust the photosensitive belt
10
.
FIG. 2
is a view of a portion of an image forming apparatus using a photosensitive drum as a photosensitive medium to solve the problems caused by the use of a photosensitive belt. Elements that are the same as those in
FIG. 1
are described with the same numerals, and thus their detailed descriptions are omitted.
Referring to
FIG. 2
, instead of the photosensitive belt
10
of
FIG. 1
, a large-sized photosensitive drum
30
is used. A plurality of developing units
28
to develop a latent electrostatic image on the photosensitive drum
30
are disposed along the circumferential surface of the photosensitive drum
30
. Developer rollers
28
a
,
28
b
,
28
c
, and
28
d
are positioned at the tip of each developing unit
28
. The developer rollers
28
a
,
28
b
,
28
c
, and
28
d
contact the photosensitive drum
30
and develop the latent electrostatic image with a toner in the developing units
28
with a developing nip N, having a predetermined width.
However, a different problem occurs in the manufacture of the photosensitive drum
30
. That is, if a small-sized photosensitive drum
30
having a diameter of 25-32 mm is manufactured, a small-sized rotary drum having a diameter of 25-32 mm is dipped in a container containing a photosensitive solution to form a photosensitive layer on the surface of the rotary drum. In this case, a plurality of small-sized rotary drums are manufactured at the same time, and thus manufacturing costs are low. However, since the photosensitive drum
30
uses a large-sized rotary drum having a diameter of about 150 mm, it is difficult to dip multiple rotary drums in the container containing the photosensitive solution. Also, it is expensive to manufacture the photosensitive drum
30
. Further, since the photosensitive drum
30
is rigid, the developing N must be narrow, and the developing units
28
do not develop the image well.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a photosensitive drum structure for an image forming apparatus in which a gap to provide a cushion between a rotary drum and a photosensitive belt is formed by adhering the photosensitive belt on steps having a predetermined height that are formed at both ends of the circumferential surface of the rotary drum.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The foregoing and other objects of the present invention are achieved by providing a photosensitive drum for an image forming apparatus, the drum including a cylindrical rotary drum having steps at both ends of a circumferential surface thereof, and a photosensitive belt wound around the rotary drum and attached thereto with an adhesive adhered to the steps, wherein a gap is formed between the circumferential surface of the rotary drum and the photosensitive belt.
According to an aspect of the present invention, the gap is filled with air or an elastic member.
REFERENCES:
patent: 4972232 (1990-11-01), Hoover et al.
patent: 5337123 (1994-08-01), Fisher
patent: 6088557 (2000-07-01), Janssen et al.
patent: 1999-25955 (1999-07-01), None
patent: 2000-9557 (2000-02-01), None
patent: 2000-5804 (2000-04-01), None
Choi Sam-seuk
Lee Jin-soo
Goodrow John
Samsung Electronics Co,. Ltd.
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