Electrophotography – Image formation – Development
Reexamination Certificate
2002-06-06
2004-02-03
Grainger, Quana M. (Department: 2852)
Electrophotography
Image formation
Development
C399S260000
Reexamination Certificate
active
06687478
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an image forming apparatus such as a copying machine or a printer using a recording technique of the electrophotographic type, the electrostatic recording type or the like, and a developer replenishing apparatus for use in such apparatus.
2. Description of Related Art
FIG. 10
of the accompanying drawings is a general construction view of a color image forming apparatus, which will be helpful in understanding the present invention. In the color image forming apparatus, four process cartridges
1
as image forming portions are detachably mounted on the main body A. These four process cartridges
1
are four yellow, magenta, cyan and black, respectively. A photosensitive drum
2
as an image bearing member is rotatably mounted in each process cartridge
1
, and a primary charger
3
, a developing portion
4
, etc. are arranged along the outer periphery of the photosensitive drum, and further a cleaning portion (not shown) etc. are provided. Image exposing light of each color is applied to each photosensitive drum
2
. In order to replenish the developing portion
4
of each process cartridge
1
with a developer, a developer replenishing portion
6
is detachably mounted on the main body A of the apparatus in the upper portion thereof.
A transferring portion
5
is provided in such a manner as to contact with each photosensitive drum
2
. The transferring portion
5
is comprised of a primary transferring portion
8
and a secondary transferring portion
9
, and the primary transferring portion
8
has an intermediate transfer belt
10
, a driving roller
11
for driving the intermediate transfer belt
10
and an intermediate roller
12
, and a primary transfer roller
13
disposed on the back side of the intermediate transfer belt
10
in opposed relationship with each photosensitive drum
2
. Also, the secondary transferring portion
9
has a secondary transfer roller
14
and a pressure roller
15
.
The main body A of the apparatus is further provided with a plurality of feed cassettes
16
containing recording materials S of respective sizes therein, and a feed portion
18
for conveying the recording materials S to a pair of registration rollers
17
, and the feed portion
18
in turn is provided with a pickup roller
19
and pairs of feed rollers
20
-
23
, and is further provided with a pair of feed rollers
24
for feeding the recording material S from an insertion port provided in the main body A of the apparatus to the pair of registration rollers
17
. The main body A of the apparatus is further provided with a fixing portion
25
for fixing the recording material S conveyed from the secondary transferring portion
9
, and a delivery portion
26
for delivering the fixed recording material S to a delivery tray.
Description will now be made of the process of forming a color image by the above-described image forming apparatus. Each photosensitive drum
2
rotated at a constant speed in the direction indicated by the arrows is first uniformly charged by the primary charger
3
, and then image exposing light of each color is applied to the surface thereof by the whole or a part of each exposing portion
7
. A latent image is formed on each image-exposed photosensitive drum
2
, and those latent images are then developed in the developing portions
4
by color toners as developers. These developed images are color developed images, but in the case of monochromatic image formation, a black developed image is formed only on the photosensitive drum
2
mounted in the process cartridge
1
for black.
Next, the developed image formed on each photosensitive drum
2
is primary-transferred in the primary transferring portion
8
. That is, the developed image is transferred (multilayer-transferred) onto the intermediate transfer belt
10
running at a constant speed in the direction indicated by the arrow by a primary transfer bias voltage applied to each primary transfer roller
13
. The developed images transferred to the intermediate transfer belt
10
are then transferred onto the recording material S in the secondary transferring portion
9
while the recording material S passes between the secondary transfer roller
14
and the pressure roller
15
. The recording material S is stopped and stands by in advance at the pair of registration rollers
17
portion, and is fed to the secondary transferring portion
9
in accordance with the transfer timing.
The recording material S to which the developed image has been transferred in the secondary transferring portion
9
is then conveyed to the fixing portion
25
, where the developers thereon are fused and fixed by heat and pressure, and the recording material S is further delivered from the delivery portion
26
onto the delivery tray.
The developing portion
4
provided in each process cartridge
1
has a developer container for containing the developer therein, agitating means for agitating the contained developer and supplying it to a developing sleeve, and a developing blade for regulating the layer thickness of the developer supplied onto the developing sleeve, and the developer on the developing sleeve is supplied onto the photosensitive drum
2
opposed to the developing sleeve with a minute gap therebetween. The developer necessary for image formation fills each developer container in advance, and as the amount of developer (filling level) in the developer container is reduced by development, the developing portion
4
may be automatically replenished with the developer from the developer replenishing portion
6
.
FIG. 11
of the accompanying drawings is a detailed cross-sectional view of the developer replenishing portion
6
shown in
FIG. 10
, and
FIG. 12
of the accompanying drawings is a right side view thereof. The developer replenishing portion
6
has an elongate main body
30
serving also as a container for containing the developer T therein, and agitating means
31
having a plurality of agitating vanes is rotatably supported in the substantially central portion of the main body
30
, and a replenishing screw
32
is rotatably supported in the lower portion of the main body
30
. Further, a developer discharge port
33
is provided in the bottom of the main body
30
so that when the developer replenishing portion
6
is mounted on the main body A of the apparatus, the developer discharge port
33
may communicate with a supply port opening to the upper portion of the developing portion
4
which is indicated by the double-dotted line.
The replenishing screw
32
is opposite in the helix direction of the screw on the left side and right side of
FIG. 11
, and when the replenishing screw
32
is clockwisely rotated, the developer T is moved from left to right toward the developer discharge port
33
and is discharged therethrough.
When the developer replenishing portion
6
is mounted on the main body A of the apparatus, the end portions of the rotary shaft
34
of the agitating means
31
and the rotary shaft
35
of the replenishing screw
32
are detachably connected to driving shafts
41
and
42
, respectively, in a driving portion
40
provided on the main body A side of the apparatus through couplings. In the case of connection, two guide pins
43
and
44
protruding from the driving portion
40
side are inserted into two guide cylinders protruding in parallel to each other from the end portion of the main body
30
, whereby accurate positioning is accomplished.
The driving portion
40
has a driving motor
45
as a drive source, and a gear mechanism
46
connected to the output shaft of the driving motor
45
. The gear mechanism
46
, as shown in
FIG. 12
of the accompanying drawings, comprises a plurality of gears, and the detecting shaft
48
of rotation amount detecting means
47
is connected to a second gear G
2
meshing with a first gear G
1
coaxially coupled to the output shaft of the driving motor
45
. A fifth gear G
5
having the driving shaft
42
coupled thereto meshes with the second gear G
2
via a third g
Matsuda Kenji
Sugita Satoshi
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Grainger Quana M.
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