Electrophotography – Having particular structure – Modular or displaceable
Reexamination Certificate
2000-04-11
2001-10-23
Chen, Sophia S. (Department: 2852)
Electrophotography
Having particular structure
Modular or displaceable
C399S124000, C399S125000
Reexamination Certificate
active
06308029
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electrophotographic image forming device, such as an electrophotographic printer, and an exchange method of a photosensitive belt and a transfer belt comprising the same. In particular, the present invention relates to an electrophotographic image forming device having a simple structure and an exchange method of a photosensitive belt and a transfer belt, which can be easily carried out.
This application is based on Japanese Patent Application No. Hei 11-105957, the contents of which are incorporated herein by reference.
2. Description of the Related Art
A conventional electrophotographic image forming device, such as an electrophotographic printer, comprises a photosensitive belt. The photosensitive belt is consumable; therefore, the photosensitive belt must be exchanged, depending on its use period or the printing frequency.
FIG. 6
shows an internal constitution of a conventional electrophotographic printer viewed from the front side.
In the conventional electrophotographic printer, a tray
29
a
for storing recording media, such as printing paper, and some pairs
32
of transferring rollers for transferring the recording medium are provided in the body
21
. The pair
32
of transferring rollers is provided with the body
21
so that each of the rollers rotates.
In addition, a photosensitive belt
22
and a belt driver
31
for the photosensitive belt
22
are provided in the body
21
. The belt driver
31
comprises four driving rollers
23
,
24
,
25
, and
26
. The three rollers
23
,
24
, and
25
among the driving rollers
23
,
24
,
25
, and
26
are located so as to form a triangle. Another driving roller
26
is located between the driving rollers
24
and
25
. The longitudinal directions of these driving rollers
23
,
24
,
25
, and
26
are parallel. The photosensitive belt
22
is located so as to contact with the surface of the driving rollers
23
,
24
,
25
, and
26
while being taut. Moreover, the driving roller
25
can shift toward the driving roller
24
. When the driving roller
25
shifts toward the driving roller
24
, the tension of the photosensitive belt
22
loosens.
A developing roller
27
is located opposite to the driving roller
26
with respect to the photosensitive belt
22
so that the developing roller
27
and driving roller
26
sandwich the photosensitive belt
22
. The developing roller
27
is provided with the body
21
so as to be able to shift downwardly. Furthermore, a transfer roller
28
is located opposite to the driving roller
23
with respect to the photosensitive belt
22
so that the transfer roller
28
and the driving roller
28
sandwich the photosensitive belt
22
and the recording medium
29
which is transferred from the tray
29
a.
The transfer roller
28
is provided with the body
21
so as to be able to shift upwardly. The developing roller
27
makes an image to be printed at the recording medium
29
onto the photosensitive belt
22
by toners thereto adhering. Then, the transfer roller
28
transfers the image comprising toners which is formed onto the photosensitive belt
22
to the recording medium
29
.
The photosensitive belt
22
provided with the conventional electrophotographic printer is changed by the following processes.
FIGS. 7A
to
7
D,
8
A, and
8
B show the exchange processes of the photosensitive belt
22
.
As shown in
FIG. 7A
, the developing roller
27
shifts downwardly, as indicated by the arrow F. Then, the transfer roller
28
shifts upwardly, as indicated by the arrow G. Thereby, the photosensitive belt
22
does not contact with the developing roller
27
and the transfer roller
28
, as shown in FIG.
7
B.
After that, the driving roller
25
shifts toward the driving roller
24
, as indicated by the arrow H in FIG.
7
C. Thereby, the tension of the photosensitive belt
22
lossens. Then, the photosensitive belt
22
is removed from the printer through the opening formed at the front of the printer by peeling the photosensitive belt
22
from the belt driver
31
, as indicated by the arrow I in FIG.
7
D.
In order to fit a new photosensitive belt
22
into the printer, the new photosensitive belt
22
is fitted with the printer by being passes through the opening formed at the front of the printer, and covering the belt driver
31
. The driving roller
25
returns to the place where it was by shifting as indicated by the arrow K in FIG.
8
B. Thereby, the photosensitive belt
22
becomes tense. Then, the developing roller
27
shifts upwardly as indicated by the arrow L, and sandwiches the photosensitive belt
22
together with the driving roller
26
opposite to the developing roller
27
. The transfer roller
28
shifts downwardly as indicated by the arrow M, and sandwiches the photosensitive belt
22
together with the driving roller
23
opposite to the developing roller
28
. The photosensitive belt
22
is exchanged by these processes.
However, in order to exchange the photosensitive belt
22
in the conventional electrophotographic printer, it is necessary to shift the developing roller
27
, the transfer roller
28
, etc., and members for shifting the developing roller
27
, the transfer roller
28
, etc. are needed. Therefore, the problem arises that the structure of the printer is complicated. In addition, the exchange method of the photosensitive belt
22
is also complicated.
It is therefore an object of the present invention to provide an electrophotographic image forming device which has a simple structure and in which a photosensitive belt or a transfer belt is easily exchanged, and an exchange method of a photosensitive belt and a transfer belt, which can be easily carried out.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention, the present invention provides an electrophotographic image forming device comprising:
a body comprising an upper housing and a lower housing,
a photosensitive belt which is provided in the body,
a belt driver for rotating the photosensitive belt, which is covered with the photosensitive belt, and
a hinge joining the upper housing, the lower housing, and the belt driver, and make the upper housing and the belt driver swing with respect to the lower housing.
According to the electrophotographic image forming device, the upper housing, the lower housing and the belt driver are joined via the hinge. When the upper housing swings with respect to the belt driver, and the belt driver swings with respect to the lower housing, the belt driver separates from the upper and lower housing. Therefore, the photosensitive belt covering the belt driver can be easily exchanged.
In particular, it is preferable that the belt driver comprises a plurality of driver rollers of which the rotation axes are parallel and a tension loosen equipment for loosing the tension of the photosensitive belt comprising at least one shiftable driver roller. According to the electrophotographic image forming device, the photosensitive belt can be easily removed from the belt driver by loosening the tension of the photosensitive belt using the tension loosen equipment.
In addition, it is preferable to provide a developing roller in the lower housing, and a transfer roller in the upper housing. When the developing roller is provided in the lower housing, and the transfer roller is provided in the upper housing, the developing roller and the transfer roller easily separates from the photosensitive belt covering the belt driver only by swinging the upper housing swings with respect to the belt driver, and the belt driver swings with respect to the lower housing. That is, according to the electrophotographic image forming device, the special equipments for displacing the developing roller and the transfer roller are not needed in order to only exchange the photosensitive belt. Therefore, the electrophotographic image forming device has a simple structure and a low manufacturing cost, compared with a conventional electrophotographic image forming device.
Accordin
Chen Sophia S.
NEC Corporation
Ngo Hoang
Ostrolenk Faber Gerb & Soffen, LLP
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