Information
-
Patent Grant
-
6356730
-
Patent Number
6,356,730
-
Date Filed
Friday, June 23, 200023 years ago
-
Date Issued
Tuesday, March 12, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Fitzpatrick, Cella, Harper & Scinto
-
CPC
-
US Classifications
Field of Search
US
- 399 274
- 399 284
- 399 350
- 399 351
- 399 126
- 118 261
- 015 2565
- 411 116
- 411 147
-
International Classifications
-
Abstract
The present invention relates to a developing apparatus, including: a developing agent carrier for carrying a developing agent to develop an electrostatic latent image formed on an image carrier with the developing agent; a regulating member for regulating a thickness of a layer of the developing agent carried by the developing agent carrier; and a securing member, provided with an engaging hole for engaging with an axis, for securing the regulating member to a main body of the developing apparatus. The securing member is provided with a cutting portion formed around the engaging hole so as to be able to absorb, in a longitudinal direction of the regulating member, a difference between elongation and contraction of the regulating member and elongation and contraction of the main body of the developing apparatus.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a developing apparatus and a cleaning apparatus suitable for use in an image forming apparatus such as a printer, a copying machine, a facsimile or the like.
2. Description of the Related Art
One example of a conventional process cartridge detachable from an image forming apparatus will hereinafter be described with reference to
FIGS. 13
to
16
. In FIG.
13
and
FIG. 14
, numeral
101
refers to a developing roller as a developing agent carrier, and a developing blade
102
as a developing agent layer thickness regulating member, disposed in parallel with a longitudinal direction of the developing roller
101
, is disposed in direct contact with a surface of the developing roller
101
. Both ends of the developing blade
102
are secured by screws to seat surfaces
104
a
of a developing container
104
.
As shown in
FIG. 14
, a pressingly contacting force between the developing blade
102
and the developing roller
101
is controlled by a flexure angle θ
1
of an elastic portion
102
a.
In
FIG. 16
, numeral
105
is a photosensitive drum, and a cleaning blade
106
as a cleaning member, disposed in parallel with a longitudinal direction of the photosensitive drum
105
, is disposed in direct contact with a surface of the photosensitive drum
105
. Similarly, the cleaning blade
106
is secured by screws
103
to seat surfaces
107
a
of a cleaning frame
107
.
As shown in
FIG. 16
, a pressingly contacting force between the cleaning blade
106
and the photosensitive drum
105
is controlled by a spacing distance (intrusion amount) Q between a virtual position of a tip of an elastic portion
106
a
of the cleaning blade
106
without the photosensitive drum
105
and a directly contacting point Y of the elastic portion
106
a
with the photosensitive drum
105
, and also by a flexure angle θ
2
of the elastic portion
106
a.
In the aforementioned conventional example, however, internal temperature of the image forming apparatus changes due to influences such as installation environment or fixing device temperature, and accompanied by this change, temperatures of respective parts inside the process cartridge change, too. When the temperature inside the apparatus rises, the developing container
104
and the developing blade
102
are elongated in right and left directions in
FIG. 15
(in an arrow a direction) according to respective coefficients of thermal expansion.
At this time, as for the developing container
104
made of resin and a sheet metal portion
102
b,
made of metal, of the developing blade
102
, the developing container
104
made of resin has a larger coefficient of liner thermal expansion (a typical resin has a coefficient of liner thermal expansion of 7×10
−5
; iron has a coefficient of liner thermal expansion 1.12×10
−5
) and a larger elongation than those of the sheet metal portion
102
b,
thereby deforming the sheet metal portion in a downward direction in
FIG. 15
(in an arrow b direction) based on screws
103
as base points provided in two spots, and therefore, the flexure angle θ
1
at a center portion in a longitudinal direction of the developing blade
102
shown in
FIG. 14
becomes smaller, with the result that a pressingly contacting force of the developing blade
102
with respect to the developing roller
101
becomes lower at the center portion in the longitudinal direction.
When a pressingly contacting force of the developing blade
102
becomes lower at the center portion of the longitudinal direction, a thickness of a toner coat and a frictionally sliding charging amount on the developing roller
101
become reduced, and therefore an image density at the center portion in the longitudinal direction becomes lowered, which might cause image unevenness.
For example, it has experimentally proved that, provided that a length of the securing portions (a spacing distance between holes for the screws
103
of the end portions) of the sheet metal portion
102
b
of the developing blade
102
is 211 mm and the temperature is changed to 30° C., a changing amount in a downward direction (in a arrow b direction) was approximately 0.4 mm at the center portion in the longitudinal direction of the developing blade
102
.
When temperature is lowered, on the other hand, the deforming direction becomes in an upward direction in
FIG. 15
(in an arrow c direction) which is an opposite direction when the temperature becomes higher, and therefore, a pressingly contacting force of the developing blade
102
becomes increased at the center portion in the longitudinal direction. Due to this, the thickness of the toner coat and the sliding-rubbing charging amount on the developing roller
101
become increased, and then an image density at the center portion in the longitudinal direction becomes higher, which might cause image unevenness.
Also, when the temperature inside the image forming apparatus rises, the cleaning frame
107
and the cleaning blade
106
shown in
FIG. 16
becomes elongated in the right and left directions in
FIG. 15
(in an arrow a direction) according to respective coefficients of thermal expansion, in the same way as that of the aforementioned developing container
104
and the developing blade
102
shown in FIG.
15
.
At this time, as for the cleaning frame
107
made of resin and a sheet metal portion
106
b,
made of metal, of the cleaning blade
106
, the cleaning frame
107
made of resin has a larger coefficient of liner thermal expansion and a larger elongation than those of the sheet metal portion
106
b,
thereby deforming the sheet metal portion in a downward direction in
FIG. 15
(in an arrow b direction) based on the screws
103
as base points provided in the two spots, and therefore, the flexure angle θ
2
at a center portion in a longitudinal direction of the cleaning blade
106
shown in
FIG. 16
becomes smaller, with the result that a pressingly contacting force of the cleaning blade
106
with respect to the photosensitive drum
105
becomes decreased at the center portion in the longitudinal direction and the intrusion amount Q with respect to the photosensitive drum
105
also becomes decreased, thus to cause problems such as a cleaning insufficiency or the like.
When temperature is lowered, on the other hand, the deforming direction becomes in an upward direction in
FIG. 15
(in an arrow c direction) which is an opposite direction when the temperature becomes higher, and therefore, a pressingly contacting force of the cleaning blade
106
becomes increased at the center portion in the longitudinal direction, and the intrusion amount Q with respect to the photosensitive drum
105
becomes in excess. Thus, when an inappropriate portion of the elastic portion
106
a
of the cleaning blade
106
, instead of the tip of the elastic portion
106
a
which is originally designed to be contacted with a surface of the photosensitive drum
105
, is contacted with the surface of the photosensitive drum
105
, cleaning insufficiency occurs; for example, residual developing agent, which is supposed to be scraped off, on the surface of the photosensitive drum
105
goes by to remain thereon. In addition, the photosensitive drum has been rubbed for a long time, which then causes problems such as a shorter lifetime of the photosensitive drum
105
.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a developing apparatus which absorbs a difference between elongation and contraction of a regulating member and elongation and contraction of a main body of the developing apparatus.
An another object of the present invention is to provide a cleaning apparatus which absorbs a difference between elongation and contraction of a cleaning member and elongation and contraction of a main body of the cleaning apparatus.
A still another object of the present invention is to provide a developing apparatus in which a positional relation between the regulating member and a developing agent carrier is not changed, irrespective of temperature changes.
A still another object of the present invention is to provide a developing apparatus in which a positional relation between the cleaning member and a body subjected to a cleaning process is not changed, irrespective of temperature changes.
Still further object and characteristics will be clear by reading the detail description of the invention described below with reference to accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects and features of the invention are apparent to those skilled in the art from the following referred embodiments thereof when considered in conjunction with the accompanied drawings, in which:
FIG. 1
is a cross-sectional explanation view showing a structure of an image forming apparatus to which a process cartridge provided with a developing apparatus and a cleaning apparatus according to the present invention is detachably mounted;
FIG. 2
is a perspective view of an exterior appearance from a right side showing a structure of the process cartridge;
FIG. 3
is a perspective view of the exterior appearance from a left side showing the structure of the process cartridge;
FIG. 4
is a transverse-sectional explanation view showing the structure of the process cartridge;
FIG. 5
is a perspective view showing a structure of a first embodiment of the developing apparatus according to the present invention;
FIG. 6
is a perspective explanation view showing a state where a developing agent carrier has been detached from the first embodiment of the developing apparatus according to the present invention;
FIG. 7
is a cross-sectional explanation view showing a structure of a securing means of a layer thickness regulating member;
FIG. 8
is a perspective explanation view showing a structure of a securing axis to be inserted into a hole provided at the layer thickness regulating member;
FIG. 9
is a cross-sectional explanation view showing the structure of the securing axis to be inserted into the hole provided at the layer thickness regulating member;
FIG. 10
is an assembling explanation view showing a structure of a second embodiment of the developing apparatus according to the present invention;
FIG. 11
is an assembling explanation view showing a structure of the cleaning apparatus according to the present invention;
FIG. 12
is a cross-sectional explanation view showing a structure of a securing means of the cleaning member;
FIG. 13
is a view showing a structure of a securing means of a developing blade according to a conventional developing apparatus;
FIG. 14
is a view showing the structure of the securing means of the developing blade according to the conventional developing apparatus;
FIG. 15
is a view explaining a problem of the securing means of the conventional developing apparatus; and
FIG. 16
is a view showing a structure of a securing means of a cleaning blade according to a conventional cleaning apparatus.
FIG. 17
is a front view and a side view of a securing member(a push nut) of a thickness-of-layer regulating member.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings, one embodiment, in which an example of an image forming apparatus provided with a process cartridge in a detachably manner including a developing apparatus and a cleaning apparatus according to the present invention, or the like is applied to a laser beam printer, will be specifically described.
FIG. 1
is a cross-sectional explanation view showing a structure of an image forming apparatus to which a process cartridge provided with a developing apparatus and a cleaning apparatus according to the present invention is detachably mounted;
FIG. 2
is a perspective view of an exterior appearance from a right side showing a structure of the process cartridge;
FIG. 3
is a perspective view of the exterior appearance from a left side showing the structure of the process cartridge;
FIG. 4
is a transverse-sectional explanation view showing the structure of the process cartridge;
FIG. 5
is a perspective view showing a structure of a first embodiment of the developing apparatus according to the present invention;
FIG. 6
is a perspective explanation view showing a state where a developing agent carrier has been detached from the first embodiment of the developing apparatus according to the present invention;
FIG. 7
is a cross-sectional explanation view showing a structure of a securing means of a layer thickness regulating member;
FIG. 8
is a perspective explanation view showing a structure of a securing axis to be inserted into a hole provided at the layer thickness regulating member; and
FIG. 9
is a cross-sectional explanation view showing the structure of the securing axis to be inserted into the hole provided at the layer thickness regulating member.
[Entire Structure]
First, referring to
FIG. 1
, an entire structure of a laser beam printer as an image forming apparatus mounting detachably a process cartridge including a developing apparatus and a cleaning apparatus according to the present invention will be explained. As shown in
FIG. 1
, in a laser beam printer A as an electrophotographic image forming apparatus, an electrophotographic photosensitive drum
2
as a image carrier with its surface uniformly charged is irradiated with a laser beam based on image information from an optical system
1
to form an electrostatic latent image, and then developing agent (hereinafter referred to as “toner”) is supplied to the electrostatic latent image to form a toner image.
Synchronously with the formation of the toner image on the photosensitive drum
2
, recording mediums P constituted of paper, synthetic resin or the like contained in a feeding cassette
3
are separately fed sheet by sheet by means of a pick-up roller
4
and a contacting member
5
for pressingly contacting therewith, and then conveyed by conveying means consisting of a pair of conveying rollers
6
, a pair of register rollers
7
and the like. Then, the toner image formed on the photosensitive drum
2
which is contained in a cartridge as a process cartridge B is applied with voltage to a transfer roller
8
as a transfer means, thus to be transferred on the recording medium P. Thereafter, the recording medium P is conveyed by a conveying belt
9
to a fixing apparatus
10
.
The fixing apparatus
10
includes a driving roller
10
a
and a heater
10
b
internally and also has a fixing rotator
10
d
constituted of a cylindrical sheet supported rotatably on a support
10
c,
where the recording medium P passing through a nip portion between the driving roller
10
a
and the fixing rotator
10
d
is heated and then subjected to pressurizing treatment, so the transferred toner image is eternally fixed.
The recording medium P is conveyed by a pair of delivering rollers
11
,
12
, through a reverse conveying path to be delivered onto a delivery section
13
. Incidentally, this laser beam printer A has a structure capable of conducting a manual feeding with a manual tray
14
and a feeding roller
15
.
[Structure of Process Cartridge]
The process cartridge B is provided with the photosensitive drum
2
and at least one of image forming process means. Here, the image forming process means include, for example, a charging means for charging the surface of the photosensitive drum
2
, a developing means for developing the electrostatic latent image formed on the photosensitive drum
2
, a cleaning means for cleaning residual toner remaining on the surface of the photosensitive drum
2
, or the like.
In the process cartridge B of the present embodiment, as shown in
FIG. 4
, the photosensitive drum
2
as an electrophotographic photosensitive member having a photosensitive layer is rotated and voltage is applied to a charging roller
16
as a charging means to charge uniformly the surface of the photosensitive drum
2
. Then, the charged photosensitive drum
2
is exposed to light image from the optical system
1
through an exposure opening
17
to form an electrostatic latent image, and thereafter the toner as a developing agent is supplied from the developing apparatus
18
as a developing means to the electrostatic latent image, thereby achieving developing process.
In the developing apparatus
18
, toner is conveyed by a rotatable toner conveying member
18
b
as a developing agent conveying means placed inside a toner container
18
a
as a developing agent container for containing the developing agent, through an opening
18
d
(See, e.g.,
FIG. 8
) of a toner frame
18
c
molding the toner container
18
c
into a developing agent container and an opening
18
f
(See, e.g.,
FIG. 6
) of a developing frame
18
e,
to be conveyed into the developing frame
18
e.
Then, the toner is agitated by a toner agitating member
18
g,
and a developing roller
19
as a developing agent carrier having a built-in stationary magnet
19
a
is rotated, and on the surface of the developing roller
19
, there is formed a toner layer provided with frictional electrification charges by a developing blade
20
as a layer thickness regulating member for regulating the layer thickness of toner attached on the surface of the developing roller
19
. The toner thus formed is transferred onto the surface of the photosensitive drum
2
where the electrostatic latent image has been formed, thus forming a toner image for visualization.
Then, after a voltage having a polarity opposite to the toner image is applied to the transfer roller
8
to transfer the toner image onto the recording medium P, the residual toner remaining on the surface of the photosensitive drum
2
is removed by a cleaning apparatus
23
where a cleaning blade
21
as a cleaning member scrapes off the residual toner on the photosensitive drum
2
, and a dip sheet
22
dips the toner to collect into a waste toner container
23
a
as a collected developing agent container.
Connecting a developing unit C integrally formed by welding together the toner frame
18
c
which constitutes the toner container
18
a
and supports the toner conveying member
18
b
so as to be rotary driven; the developing frame
18
e
having built-in developing means such as the toner agitating member
18
g,
the developing roller
19
, the developing blade
20
or the like; and a covering member
18
h,
with the cleaning frame
23
b
constituting the waste toner container
23
a
and having the photosensitive drum
2
, the cleaning blade
21
, the dip sheet
22
and the charging roller
16
then constitutes a cartridge frame in which the respective members such as photosensitive drum
2
or the like are contained, thereby making the frame usable as a cartridge which is detachably mounted with respect to a cartridge mounting means provided in the main body of the image forming apparatus.
As for the cartridge means, when an opening and closing member
24
is opened at an axis
24
a
as a center shown in
FIG. 1
, a space of the cartridge mounting section appears, and in the right and left sides, there are arranged cartridge mounting guide members (not shown). Guides consisting of bosses
25
a
and ribs
25
b
shown in FIG.
2
and
FIG. 3
of a process cartridge B are introduced so as to be fitted to the mounting guides (not shown), and the process cartridge B is detached from the main body of the image forming apparatus.
It is to be noted that, as shown in FIG.
4
and
FIG. 5
, an arm portion
26
is protruding over the developing frame
18
e
toward the cleaning frame
23
b.
The tip of this arm portion
26
is connected with the cleaning frame
23
b
by a pin
27
as shown in
FIG. 4
so that both can rotate freely with respect to each other. Then, a compressing coil spring
28
is pressingly provided between the arm portion
26
extending to the developing unit C of the cleaning frame
23
b
and the developing frame
18
e,
thereby making the developing roller
19
pressingly contacted with the photosensitive drum
2
.
As shown in
FIG. 5
, both the ends outside the image forming region of the developing roller
19
are provided with spacer rollers
29
having respectively a larger diameter than that of the developing roller
19
, and the spacer rollers
29
are pressingly contacted with the photosensitive drum
2
, thereby obtaining a gap of approximately 300 μm, in the developing region, between the photosensitive drum
2
and the developing roller
19
.
As materials for forming the toner frame
18
c
and the developing frame
18
e,
plastics are employed including, for example, polystyrene, ABS resin (acrylonitrile/butadiene/styrene copolymer), denatured PPE resin (polyphenylene ether), denatured PPO resin (polyphenylene oxide), polycarbonate, polyethylene, polypropylene or the like.
As shown in FIG.
8
and
FIG. 9
, in the present embodiment, two metal axes
30
are standingly disposed in a protruding manner at the both ends in a longitudinal direction of seat surfaces
18
i,
to which the developing blade
20
is secured, of the developing frame
18
as the main body of the developing apparatus.
The metal axis
30
may be provided, for example, by insert molding at the same time when the molding of the developing frame
18
e
is carried out; or as shown in
FIG. 9
, it may be secured by being pressingly fitted into a hole
18
j
having a stepped portion for attaching the metal axis
30
thereto, the hole
18
j
being formed from a side opposite to the seat surface
18
i
for attaching the developing blade
20
thereto, to the developing frame
18
(an arrow d direction in FIG.
9
).
On the other hand, the developing blade
20
is provided with an elastic blade and a sheet metal portion
20
a
as a supporting member for supporting the elastic blade, and the sheet metal portion
20
a
of the developing blade
20
is punched with a circular hole
20
a
1
having a diameter corresponding to the outer diameter of the metal axis
30
and a longer hole
20
a
2
having a major axis which is larger than the outer diameter of the metal axis
30
, where those holes are designed to be fitted with the metal axis
30
provided in a standing manner which protrudes beyond the seat surface
18
i
of the developing frame
18
e.
As for the longer hole
20
a
2
, a diameter in a direction perpendicular to the longitudinal direction of the developing blade corresponds to the outer diameter of the metal axis
30
, but a diameter in the longitudinal direction of the developing blade is larger than that of the metal axis
30
, with the result that the developing blade is designed to be allowed to move substantially only in the longitudinal direction.
When the developing blade
20
is secured to the seat surface
18
i
of the developing frame
18
e,
the metal axis
30
projecting from the seat surface
18
i
is fitted into the hole
20
a
1
and the longer hole
20
a
2
formed on the sheet metal portion
20
a
of the developing blade
20
to make the sheet metal portion
20
a
of the developing blade
20
directly contacted with the seat surface
18
i,
and then a push nut
31
as a securing means is fittingly mounted on the metal axis
30
to be engagingly stopped thereto, thereby securing the developing blade
20
to the seat surface
18
i
of the developing frame
18
e.
As shown in FIG.
7
and
FIG. 17
, the push nut
31
is constituted of: a flat base plate portion
31
a
(a base body portion) formed at an outer edge portion (outer peripheral portion); a penetrating hole
31
b,
formed at approximately the center portion of the push nut
31
, into which the metal axis
30
is inserted; a plurality of cutting portions formed with a predetermined interval respectively, from the side of the penetrating hole
31
b
to the direction of the diameter of the penetrating hole
31
b
at a part from the base plate portion
31
a
toward the penetrating hole
31
b;
and a plurality of sloping pieces
31
c
formed by bending a part nipped by the cutting portions into respectively one surface side.
As for the push nut
31
, the sloping piece
31
c
as a nail portion for engaging with the metal axis
30
to be engagingly stopped has an elasticity, so the fastening force is slightly weaker than that of the aforementioned screws
103
in the conventional example, and also the sheet metal portion
20
a
of the developing blade
20
is pushed onto the seat surface
18
i
of the developing frame
18
e
with a predetermined force to be secured thereto, and therefore the elastic portion
20
b
of the developing blade
20
is directly contacted with the surface of the developing roller
19
with a predetermined force.
Since one of the holes formed on the sheet metal portion
20
a
of the developing blade
20
for being attached to the metal axis
30
is the longer hole
20
a
2
and the push nut
31
has the cutting portions, when the developing frame
18
e
is deformed due to temperature changes, a sliding is produced in the longitudinal direction between the sheet metal portion
20
a
of the developing blade
20
, and the developing frame
18
e
as well as the push nut
31
, thereby suppressing the deformation of the developing blade
20
like the aforementioned conventional example. As a result, a pressingly contacting force of the developing blade
20
can be maintained constantly.
As a material for the metal axis
30
protruding beyond the seat surface
18
i
of the developing frame
18
e,
it is preferred to have a hardness which enables the sloping piece
31
c
as a nail portion of the push nut
31
to be bitten into the metal axis
30
at the time of attaching the push nut
31
, thus to bring about the fastening force; for example, such a material as having a hardness HV=around 300 to 400 of Vickers hardness, more specifically, stainless steel or the like is desirable, but it is not limited to this as long as foreign substances such as generated cut powders or the like are removed by carrying out air vacuuming or the like at the time of attaching the push nut
31
.
In addition, in order to carry out easily and certainly the operation of attaching the push nut
31
, a tip portion of the metal axis
30
preferably forms a beveled portion
30
a.
With the above structure where the metal axis
30
disposed on the seat surface
18
i
of the developing frame
18
e
is fitted into the hole
20
a
1
and the longer hole
20
a
2
formed in the sheet metal portion
20
a
of the developing blade
20
, which is then engagingly stopped by the push nut
31
to be secured thereto, a major axis range of the longer hole
20
a
2
can absorb a difference in elongation and contraction due to the difference in coefficients of thermal expansion between the developing frame
18
e
and the sheet metal portion
20
a
of the developing blade
20
, resulting in that, without producing a difference in flexure angles between the end portions and the center portion in the longitudinal direction of the developing blade
20
, and also without producing a difference in pressingly contacting forces with respect to the developing roller
19
, occurrence of image defectiveness becomes preventable.
Next, referring to
FIG. 10
, a second embodiment of the developing apparatus according to the present invention will be described.
FIG. 10
is an assembling explanation view showing a structure of the second embodiment of the developing apparatus according to the present invention. It is to be noted that descriptions for the members structured in the same way as those of the aforementioned first embodiment will be omitted by providing the identical numerals.
In the aforementioned first embodiment, one example where the developing blade
20
as a layer thickness regulating member is integrally formed of the sheet metal portion
20
a
and the elastic portion
20
b
was described, but in the second embodiment, as shown in
FIG. 10
, an elastic blade
41
made of elastic material is sandwiched between two pieces of supporting plates
42
,
43
made of metal, to be secured onto the seat surface
18
i
of the developing frame
18
e.
The elastic blade
41
and the supporting plates
42
,
43
are punched with holes
41
a
1
,
42
a
1
, and
43
a
1
having respectively a diameter corresponding to the outer diameter of the metal axis
30
and longer holes
41
a
2
,
42
a
2
, and
43
a
2
having respectively a major diameter which is larger than the outer diameter of the metal axis
30
, where those holes are designed to be fitted with the metal axis
30
provided in a standing manner which is protruding beyond the seat surface
18
i
of the developing frame
18
e.
After sequentially fitting the metal axis
30
into, first, the hole
42
a
1
and the longer hole
42
a
2
in the supporting plate
42
, next the hole
41
a
1
and the longer hole
41
a
2
in the elastic blade
41
, and further the hole
43
a
1
and the longer hole
43
a
2
in the supporting plate
43
, the elastic blade
41
in a state of being sandwiched between the supporting plates
42
,
43
is then directly contacted with the seat surface
18
i
of the developing frame
18
e,
and then the metal axis
30
is secured by fittingly mounting the push nut
31
thereon.
In the present embodiment, a major axis range of the respective longer holes
41
a
2
,
42
a
2
and
43
a
2
can also absorb a difference in elongation and contraction due to the difference in coefficients of thermal expansion between the elastic blade
41
and the supporting plates
42
,
43
, resulting in that, without producing a difference in flexure angles between the end portions and the center portion in the longitudinal direction of the elastic blade
41
, and also without producing a difference in pressingly contacting forces with respect to the developing roller
19
, occurrence of image defectiveness becomes preventable. Other configurations are formed in the same way as that of the first embodiment, and the same advantages can be obtained.
Next, a structure of a cleaning apparatus according to the present invention will be described with reference to
FIG. 4
, FIG.
11
and FIG.
12
.
FIG. 11
is an assembling explanation view showing a structure of the cleaning apparatus according to the present invention and
FIG. 12
is a cross-sectional explanation view showing a structure of a securing means of the cleaning member. It is to be noted that descriptions for the members structured in the same way as those of the respective embodiments will be omitted by providing the identical numerals.
As shown in FIG.
11
and
FIG. 12
, in the present embodiment, two metal axes
30
are standingly disposed in a protruding manner at the both ends in a longitudinal direction of seat surfaces
23
c,
to which a cleaning blade
21
as a cleaning member is secured, of a cleaning frame
23
b
as a main body of the developing apparatus.
Similar to the aforementioned embodiment, the metal axis
30
may be provided, for example, by insert molding at the same time when the molding of the cleaning frame
23
b
is carried out; or as shown in
FIG. 12
, it may be secured by being pressingly fitted into a hole
23
d
having a stepped portion for attaching the metal axis
30
thereto, the hole
23
d
being formed from a side opposite to the seat surface
23
c
for attaching the cleaning blade
21
thereto, to the cleaning frame
23
b
(from a left side direction in FIG.
12
).
On the other hand, the sheet metal portion
21
a
of the cleaning blade
21
is punched with a hole
21
a
1
having a diameter corresponding to the outer diameter of the metal axis
30
and a longer hole
21
a
2
having a major axis which is larger than the outer diameter of the metal axis
30
, where those holes are designed to be fitted with the metal axis
30
provided in a standing manner which protrudes beyond the seat surface
23
c
of the cleaning frame
23
b.
When the cleaning
21
is secured to the seat surface
23
c
of the cleaning frame
23
b,
the metal axis
30
projecting from the seat surface
23
c
is fitted into the hole
21
a
1
and the longer hole
21
a
2
formed in the sheet metal portion
21
a
of the cleaning blade
21
to make the sheet metal portion
21
a
of the cleaning blade
21
directly contacted with the seat surface
23
c,
and then the aforementioned push nut
31
as a securing means is fittingly mounted on the metal axis
30
to be engagingly stopped thereto, thereby securing the cleaning blade
21
to the seat surface
23
c
of the cleaning frame
23
b.
As for the push nut
31
, the sloping piece
31
c
as a nail portion for engaging with the metal axis
30
to be engagingly stopped has an elasticity, so the fastening force is slightly weaker than that of the aforementioned screw
103
in the conventional example, and also the cleaning blade
21
is pushed onto the seat surface
23
c
of the cleaning frame
23
b
with a predetermined force to be secured thereto, and therefore an elastic portion
21
b
of the cleaning blade
21
is directly contacted with the surface of the photosensitive drum
2
with a predetermined force.
Since one of the holes formed on the sheet metal portion
21
a
of the cleaning blade
21
for being attached to the metal axis
30
is the longer hole
21
a
2
, when the cleaning frame
23
b
is deformed due to temperature changes, a sliding is produced in the longitudinal direction between the sheet metal portion
21
a
of the cleaning blade
21
, and the cleaning frame
23
b
as well as the push nut
31
, thereby suppressing the deformation of the cleaning blade
21
like the aforementioned conventional example. As a result, a pressingly contacting force and an intrusion amount Q (See,
FIG. 16
) of the cleaning blade
21
can be maintained constantly.
With the above structure where the metal axis
30
disposed in a standing manner on the seat surface
21
a
of the cleaning frame
23
b
is fitted into the hole
21
a
1
and the longer hole
21
a
2
formed in the sheet metal portion
21
a
of the cleaning blade
21
, which is then engagingly stopped by the push nut
31
, a major axis range of the longer hole
21
a
2
can absorb a difference in elongation and contraction due to the difference in coefficients of thermal expansion between the cleaning frame
23
b
made of resin and the sheet metal portion
21
a
made of metal of the cleaning blade
21
, resulting in that, without producing: a difference in flexure angles between the end portions and the center portion in the longitudinal direction of the cleaning blade
21
; a difference in pressingly contacting forces with respect to the photosensitive drum
2
; and a difference in intrusion amounts with respect to the photosensitive drum
2
, occurrence of cleaning insufficiency becomes preventable and a lifetime of the photosensitive drum
2
can be improved as well.
It is to be noted that the present invention can be applied not only to a process cartridge such as e process cartridge C of the aforementioned respective embodiment for forming a monochromatic image, but also to such a process cartridge that comprises a plurality of the developing means for forming a multicolor image (for example, two-color image, three-color image, or full-color image).
The electrophotographic photosensitive member is not necessarily limited to the photosensitive drum
2
, but the following various compositions are applicable. That is, as a photosensitive member, photoconductive material is utilized, and the photoconductive materials include, for example, amorphous silicon, amorphous selenium, zinc oxide, titanium oxide, organic photoconductive material (OPC) or the like.
As a mounted shape of the photosensitive member, for example, a drum shape, a belt shape or the like is used. Generally the drum shape or the belt shape are employed; for example, in the drum type photosensitive member, the photoconductive material is vapor deposited or applied onto a cylinder of an aluminum alloy or the like.
Furthermore, as the charging means constitution, in the first embodiment, the so-called contact charging method is used, but another constitution may be used, which comprises applying a metal shield of aluminum or the like to a three-way periphery of a conventionally used tungsten wire; moving a positive or negative ion generated by applying a high voltage to the tungsten wire to the surface of the photosensitive drum
2
; and uniformly charging the surface of the photosensitive drum
2
.
It is to be noted that, as the charging means, besides the aforementioned roller type, a blade type using a charging blade, a pad type, a block type, a rod type, a wire type and the like may be used.
Also, the above-described process cartridge is provided with, for example, an electrophotographic photosensitive member and at least one of image forming process means.
In other words, the above-described process cartridge is an integrally formed cartridge including at least one of a charging means, a cleaning means, or a developing means, and an electrophotographic photosensitive member, and this process cartridge is structured so as to be detachable from the main body of the image forming apparatus.
It is to be noted that, in the aforementioned respective embodiments, a laser beam printer was chosen as an example of the image forming apparatus, but the present invention is also applicable to other forms of image forming apparatuses such as an electrophotographic copying machine, facsimile, word processor, or the like.
According to the above-described embodiments, such a process cartridge can be provided, the process cartridge including a developing apparatus which absorbs a difference in elongation and contraction due to a difference in coefficients of thermal expansion between a layer thickness regulating member for regulating a layer thickness of a developing agent attached on a surface of a developing carrier and a main body of the developing apparatus for supporting the layer thickness regulating member, or a cleaning apparatus which absorbs a difference in elongation and contraction due to a difference in coefficients of thermal expansion between a cleaning member for collecting the developing agent remaining on the surface of the image carrier and a main body of the cleaning apparatus for supporting the cleaning member, thus capable of preventing the cleaning insufficiency, or other members.
In other words, because a securing axis mounted on the main body of the developing apparatus is fitted into a hole and longer hole formed in the layer thickness regulating member, which is then engagingly stopped by a fixing means to be secured thereto, a major axis range of the longer hole can absorb a difference in elongation and contraction due to the difference in coefficients of thermal expansion between the main body of the developing apparatus and the layer thickness regulating member, resulting in that, without producing a difference in flexure angles between the end portions and the center portion in the longitudinal direction of the layer thickness regulating member, and also without producing a difference in pressingly contacting forces with respect to the developing agent carrier, occurrence of image defectiveness becomes preventable.
In addition, because a securing axis mounted on the main body of the cleaning apparatus is fitted into a hole and a longer hole formed in the cleaning member, which is then engagingly stopped by a securing means, a major axis range of the longer hole can absorb a difference in elongation and contraction due to the difference in coefficients of thermal expansion between the main body of the cleaning apparatus and the cleaning member, resulting in that, without producing: a difference in flexure angles between the end portions and the center portion in the longitudinal direction of the cleaning member; a difference in pressingly contacting forces with respect to the image carrier; and a difference in intrusion amounts with respect to the image carrier, occurrence of cleaning insufficiency becomes preventable and a lifetime of the image carrier can be improved as well.
Claims
- 1. A developing apparatus, comprising:a developing agent carrier for carrying a developing agent to develop an electrostatic latent image formed on an image carrier with the developing agent; a regulating member for regulating a thickness of a layer of the developing agent carried by the developing agent carrier; and a securing member, provided with an engaging hole for engaging with a pin, for securing said regulating member to a main body of the developing apparatus, wherein said securing member is provided with at least one cutting portion formed around the engaging hole so as to be able to absorb, in a longitudinal direction of said regulating member, a difference between elongation and contraction of said regulating member and elongation and contraction of the main body of the developing apparatus.
- 2. The developing apparatus according to claim 1,wherein the main body of the developing apparatus is provided with the pin, wherein said regulating member is provided with a longer hole through which the pin is fitted, the longer hole having a larger diameter in the longitudinal direction, and wherein said securing member is engaged with the pin, which has been fitted through the longer hole.
- 3. The developing apparatus according to claim 2,wherein the pin is mounted in a manner of protruding beyond a surface which attaches said regulating member to the main body of the developing apparatus.
- 4. The developing apparatus according to claim 3, wherein the pin is made of a metal.
- 5. The developing apparatus according to claim 2,wherein said regulating member is provided with an elastic blade and a supporting member for supporting said elastic blade, and wherein said supporting member is secured by said securing member to the main body of the developing apparatus.
- 6. The developing apparatus according to claim 1,wherein said securing member is provided with a base body portion extending along an outer periphery of said securing member, the engaging hole formed approximately at the center portion, and a sloping portion sloping from the base body portion toward the engaging hole, and wherein a plurality of cutting portions is provided respectively in a manner of extending radially.
- 7. The developing apparatus according to claim 1, wherein said securing member has an elastic property.
- 8. The developing apparatus according to claim 1, wherein the developing apparatus, together with the image carrier, is mounted in a process cartridge detachable from an image forming apparatus.
- 9. A cleaning apparatus comprising:a cleaning member for cleaning a developing agent from a body subjected to a cleaning process by contacting the body subjected to the cleaning process; and a securing member, provided with an engaging hole for engaging with a pin, for securing said cleaning member to a main body of the cleaning apparatus, wherein said securing member is provided with at least one cutting portion formed around the engaging hole so as to be able to absorb a difference between elongation and contraction of said cleaning member in a longitudinal direction of said cleaning member and elongation and contraction of the main body of the cleaning apparatus.
- 10. The cleaning apparatus according to claim 9,wherein the main body of the cleaning apparatus is provided with the pin, wherein said cleaning member is provided with a longer hole through which the pin is fitted, the longer hole having a larger diameter in the longitudinal direction, and wherein said securing member is engaged with the axis which has been fitted through the longer hole.
- 11. The cleaning apparatus according to claim 10,wherein the pin is mounted in a manner of protruding beyond a surface which attaches said cleaning member to the main body of the cleaning apparatus.
- 12. The cleaning apparatus according to claim 11, wherein the pin is made of a metal.
- 13. The cleaning apparatus according to claim 9,wherein said securing member is provided with a base body portion extending along an outer periphery of said securing member, the engaging hole formed approximately at the center portion, and a sloping portion sloping from the base body portion toward the engaging hole, and wherein a plurality of cutting portions is provided respectively in a manner of extending radially.
- 14. The cleaning apparatus according to claim 9,wherein said cleaning member is provided with an elastic blade and a supporting member for supporting the elastic blade, and wherein the supporting member is secured by said securing member to the main body of the cleaning apparatus.
- 15. The cleaning apparatus according to claim 9, wherein said securing member has an elastic property.
- 16. The cleaning apparatus according to claim 9, wherein the cleaning apparatus, together with an image carrier, is mounted in a process cartridge detachable from an image forming apparatus.
Priority Claims (1)
Number |
Date |
Country |
Kind |
11-178969 |
Jun 1999 |
JP |
|
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Number |
Name |
Date |
Kind |
4548490 |
Stirrat et al. |
Oct 1985 |
A |
5812918 |
Nakaue et al. |
Sep 1998 |
A |
6282395 |
Nittani et al. |
Aug 2001 |
B1 |
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Number |
Date |
Country |
01-219859 |
Sep 1989 |
JP |
06-130877 |
May 1994 |
JP |