Electrophotography – Image formation – Photoconductive member
Reexamination Certificate
2000-10-30
2002-05-07
Grainger, Quana M. (Department: 2852)
Electrophotography
Image formation
Photoconductive member
Reexamination Certificate
active
06385418
ABSTRACT:
CROSS REFERRENCE TO RELATED APPLICATIONS
This application claims priority under 35 USC §119 to Japanese Patent Application No. 11-309013 filed on Oct. 29, 1999, the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to an image forming apparatus, such as a copier, a printer, a facsimile, a duplicator, and a combined machine combining these image-forming apparatuses, and in particular relates to a rotation member driving apparatus for use in the image forming apparatus.
2. Discussion of the Background Art
It is well known, in an image-forming apparatus having a drum shaped photo-conductive member (hereinafter referred to as a PC drum), that the PC drum and its peripheral units are made into a single unit detachable in relation to an essential structure of the image forming apparatus (hereinafter simply referred to as a body). Such a detaching operation is generally performed as a countermeasure against fatigue made by time elapsing of the PC drum each time when, e.g., a unit of 100 thousand of image formations has been made to replace with a new PC drum unit. To improve performance of the detaching operation, the following background rotating member-driving apparatus illustrated in
FIGS. 7 through 11
is generally utilized.
As illustrated in
FIG. 9
, the PC drum
1
is configured to be cylindrical. The right side of the PC drum
1
should be a rear side of the body, and the left side thereof should be a front side of the body. A flange
2
is integrally provided to support an end of the PC drum
1
. A driving shaft guiding hole
3
is provided to penetrate the flange
2
. A guiding hole
4
having a diameter larger than the driving shaft-guiding hole
3
is provided in the vicinity and at the right side of the driving shaft-guiding hole
3
.
A separation wall is provided as a border between the driving shaft guiding hole
3
and the guiding hole
4
. Four convex portions
5
and four concave portions
6
are each respectively disposed on a cross at the guiding hole
4
side of the separation wall. The four convex portions
5
and the four concave portions
6
collectively constitute a driving force receiving joint
11
as claimed.
A PC drum unit (not shown) pivotally supports the PC drum
1
at the end of the front side of the PC drum
1
. The PC drum unit is detachably attached to the body from the front side to the rear side (not shown) of the body. When the PC drum unit is attached to the body, a rotational motive power of the driving shaft
7
can be transmitted to the flange
2
, then to the PC drum
1
.
As illustrated in
FIG. 7
, a penetrating hole
9
is formed in the driving shaft
7
at the vicinity of the front side end of the driving shaft
7
, and penetrates in a direction of the diameter of the driving shaft
7
. As illustrated in
FIGS. 8A and 7
, a driving force transferring member
10
is attached to the driving shaft
7
as described earlier. The driving force transferring member
10
is formed almost in a cylindrical shape and is slides to fit with the driving shaft
7
.
Continuing with
FIG. 8A
, a driving side joint
12
is formed at the front side end of the driving force transferring member
10
. Four convex portions
15
and four concave portions
14
are formed on the driving side joint
12
on a circumference concentric with the driving force transferring member
10
and disposed respectively on a cross. Thus, these four convex portions
14
and the four concave portions
15
can mesh with the corresponding convex portions
5
and concave portions
6
, of FIG.
9
.
Back to
FIG. 7
, an oblong hole
16
is formed on another side of the driving force transferring member
10
in the vicinity of the driving side joint
12
. Thus, when assembling the driving force transferring member
10
to the driving shaft
7
, the driving force transferring member
10
, and, the driving side joint
12
are fitted with the driving shaft
7
. The driving force transferring member
10
is directed to the rear side of the body. The oblong hole
16
is then positioned above the penetrating hole
9
. A spring pin
8
is inserted into both the oblong hole
16
and the penetrating hole
9
with pressure.
In
FIGS. 8A
,
8
B, and
8
C, the shorter diameter of the oblong hole
16
is represented by W
1
. A diameter of the spring pin
8
is represented by D
1
. The diameter D
1
should be measured in a diameter changeable direction by including a split portion
8
a
in the condition that a force is not applied to the spring pin
8
. A diameter perpendicular to the diameter D
1
is represented by D
2
. In this example, each diameter is predetermined as follows.
D
2
=1.95 mm
D
1
=2.15 mm
W
1
=2.1 through 2.2 mm
When the spring pin
8
is to be inserted into the penetrating hole
9
through the oblong hole
16
, the spring pin
8
is inserted with the slot portion being engaged with the oblong hole
16
. Thus, impediment to be produced when the insertion is made can be relatively reduced.
Thus, the driving force transferring member
10
can slide while being guided by the spring pin
8
during a stroke of the oblong hole
16
. In addition, the driving force transferring member
10
can move under the condition where the spring pin
8
fitting into the oblong hole deforms as little as possible in the direction in parallel to the shorter diameter W
1
. The oblong hole
16
has both ends each having a curvature fitting with an outer surface of the spring pin
8
to improve contacting efficiency of the spring pin
8
when the spring pin
8
contacts the end. A protruding portion of the spring pin
8
protruding from the driving shaft
7
is designed with nearly the same thickness of the cylinder of the driving force transferring member
10
.
Referring to
FIG. 7
, when the driving force transferring member
10
is assembled to the driving shaft
7
, a coil spring
17
is set around both of the driving shaft
7
and the driving force transferring member from the rear side of the driving shaft
7
, and, accordingly, the driving force transferring member. An E-shaped ring
18
is attached to a groove
19
formed around the driving shaft
7
while the front end of the coil spring
17
contacts the joint
15
and the rear side of the coil spring pin
17
is positioned at the front side than the groove
18
.
Thus, the E-shaped ring
18
can stop the rear side of the coil spring
17
, and, as a result, the coil spring
17
engages the driving force transferring member
12
. Thus, the driving force transferring member
12
is always biased to the front side of the body.
When no force is applied to the driving force transferring member
12
, one end of the oblong hole
16
, i.e., the end of the rear side of the oblong hole
16
, contacts the spring pin
8
with some bias made by the coil spring
17
as illustrated in FIG.
9
. Conversely, if any force directing to the rear side of the body is applied to the driving force transferring member
10
, the spring pin
8
changes its position to the other end of the oblong hole
16
, i.e., the front side of the body, or in the vicinity thereof as illustrated in FIG.
2
.
Thus, movement of the driving force transferring member
10
ranges from a position where one end (not shown) of the oblong hole
16
contacts the spring pin
8
to a position where the other end of the oblong hole
16
contacts the spring pin
8
.
In
FIG. 9
, the driving shaft
7
is supported by the apparatus body (not shown) at its rear side end so as not to be displaced either toward the front side or the rear side of the body. The driving shaft
7
is engaged with a driving motor via gears of driving force transmitting power as mentioned later.
Still referring to
FIG. 9
, when the PC drum
1
is to be attached to the driving shaft
7
, an operator firstly lifts the PC drum
1
together with the PC drum unit (not shown). The operator inserts the same toward the rear side of the body in a manner that an axis of the driving shaft-guiding hole
3
substant
Grainger Quana M.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Ricoh & Company, Ltd.
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