Electrophotography – Having particular structure – Modular or displaceable
Reexamination Certificate
2002-10-10
2004-12-28
Pendegrass, John (Department: 2852)
Electrophotography
Having particular structure
Modular or displaceable
C347S138000, C347S257000
Reexamination Certificate
active
06836631
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image forming apparatus using an electrophotographic process, such as a copying machine and a printer.
2. Related Background Art
FIG. 5
is a cross-sectional view of an image forming apparatus. As shown in
FIG. 5
, in a conventional image forming apparatus
30
, a photosensitive drum
38
is provided inside the apparatus. A charger
35
and a developing unit
36
are provided adjacently around the photosensitive drum
38
. Moreover, a transfer unit
37
and a fixing device
40
are disposed around the photosensitive drum
38
.
Moreover, a light scanning unit
10
is provided in the vicinity of to the photosensitive drum
38
. Furthermore, a sheet of paper
42
, and feed and transport rollers
43
,
44
,
45
capable of successively transporting the sheet of paper
42
are provided below the photosensitive drum
38
. Moreover, an image information controller
33
and a reader unit
32
capable of reading an original are provided above the photosensitive drum
38
in an upper part of the image forming apparatus
30
.
The light scanning unit
10
provided in the image forming apparatus
30
is for writing on the photosensitive drum
38
using a laser beam.
FIG. 6
is a schematic diagram of a side inner part of the light scanning unit
10
.
As shown in
FIG. 6
, the light scanning unit
10
has a structure contained in an optical box
20
. That is, the light scanning unit
10
comprises a semiconductor laser as the light source, a collimator lens and a cylinder lens (not shown), a polygon mirror
19
, scanning lenses
21
,
22
, turn-back mirrors
25
,
26
,
27
, a lengthy cylinder lens
29
, and an irradiation window
28
in the optical box
20
.
Moreover, a laser beam through inside the light scanning unit
10
shown in
FIG. 6
is first outputted from the semiconductor laser, collimated by the collimator lens so as to be inputted in the polygon mirror
19
, and deflected by the polygon mirror
19
. Then, the laser beam passes through inside the optical box
20
so as to be reflected successively by the turn-back mirrors
25
,
26
. Accordingly, the laser beam is reflected so as to pass through the optical parts in the upper and lower two spaces inside the optical box
20
.
The light scanning unit
10
with the above-mentioned configuration is mounted on a frame provided in the image forming apparatus
30
with a high accuracy.
The above-mentioned light scanning unit
10
is replaced per unit due to the life of the parts such as exhaustion of the parts in the market. For the unit replacement, the unit can be replaced after detaching the constituent parts such as the reader unit
32
provided in the main body upper part of the image forming apparatus
30
, or the unit can be replaced by sliding and moving from the side of the image forming apparatus
30
without detaching the constituent parts such as the reader unit
32
in the main body upper part.
In the case of the unit replacement after detaching the constituent parts such as the reader unit
32
in the main body upper part in the former case, since the upper part of the image forming apparatus
30
can be opened, the light scanning unit
10
can be fastened using a screw or the like from above. Thereby, the light scanning unit
10
can be fixed stably.
In contrast, in the case of the unit replacement without detaching the constituent parts such as the reader unit
32
in the main body upper part in the latter case, as shown in
FIG. 6
, an auxiliary part
49
is mounted preliminarily on the light scanning unit
10
.
Then, the light scanning unit
10
is guided to a predetermined position in the main body using a rail (not shown) provided in the main body. After abutting against the auxiliary part
49
with a main body fitting part
50
by the guiding operation, the auxiliary part
49
is forced against the main body fitting part
50
sideways using a fixing member such as a screw
51
. Thereby, the light scanning unit
10
is provided without movement particularly in the horizontal direction.
However, according to the former method of the two kinds of the detaching and replacing methods for the above-mentioned light scanning unit
10
, since all the constituent parts such as the reader unit
32
are detached, excessive labor and long time are required, and thereby the unit replacement itself is extremely inefficient.
In contrast, according to the latter method, the light scanning unit
10
is attached/detached while sliding from the side of the main body without detaching the reader unit
32
. In the case of this method, since the light scanning unit
10
can move to a considerably deep part of the main body inside and the reader unit
32
is not detached, it is difficult to fix the light scanning unit
10
from above by a screw or the like.
Furthermore, the light scanning unit
10
is disposed only by abutting in the lateral direction so as to be stabilized using the gravitational force of the light scanning unit
10
. Therefore, the close contact property of the light scanning unit
10
to the installation part at the time of fixing is low.
Thereby, an adverse effect is provided to the image quality due to generation of backlash derived from the vibration generated from the light scanning unit
10
itself or the image forming apparatus
30
main body and generation of the error of the installation accuracy itself.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an image forming apparatus capable of mounting an optical unit from sideways.
Another object of the present invention is to provide an image forming apparatus with a high stability in an optical unit.
A still another object of the present invention is to provide an image forming apparatus comprising:
an image bearing member;
an optical unit for image exposure of the image bearing member, the optical unit being mountable from sideways of the apparatus main body; and
an elastic member for pressuring the optical unit downward.
A further object of the present invention will be apparent by the explanation provided below.
REFERENCES:
patent: 5001499 (1991-03-01), Waragai et al.
patent: 5063409 (1991-11-01), Nakajima
patent: 5751431 (1998-05-01), Taka et al.
patent: 6236820 (2001-05-01), Nakazato et al.
patent: 58-078172 (1983-05-01), None
patent: 04-261564 (1992-09-01), None
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Pendegrass John
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