Information
-
Patent Grant
-
6438347
-
Patent Number
6,438,347
-
Date Filed
Friday, March 26, 199925 years ago
-
Date Issued
Tuesday, August 20, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Fitzpatrick, Cella, Harper & Scinto
-
CPC
-
US Classifications
Field of Search
US
- 399 284
- 399 274
- 399 350
- 399 351
- 399 174
-
International Classifications
-
Abstract
In a developing device, a developer carrier carries developer and a control member controls the thickness of the developer on the developer carrier. The control member has an abutting member that abuts against a reference plane of a main body of the developing device and an elastic member that overlaps the abutting member. The elastic member is urged toward the developer carrier and has a center portion of the overlapped sections of the elastic member and the abutting member that is wider than the end portions of the overlapped sections. An overlap member overlaps the elastic member.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a developing device and to a process cartridge for use in, for example, an electrophotographic image forming apparatus.
As employed herein, a “process cartridge” refers to a cartridge including at least one of a unit for charging an electrophotographic photosensitive member, a unit for developing a latent image formed on the electrophotographic photosensitive member, and a unit for removing developer remaining on the electrophotographic photosensitive member integrally formed with the electrophotographic photosensitive member in a cartridge. The cartridge can be attached to and detached from the main body of the electrophotographic image forming apparatus.
In addition, a “developing cartridge”, described hereinbelow, refers to a cartridge including a unit for developing a latent image formed on an electrophotographic photoconductive drum using toner integrally formed with a toner frame for accommodating the toner in a cartridge, and is removably attached to an image forming apparatus main body.
In this specification, a “longitudinal direction” refers to a direction that is perpendicular to a conveyance direction of a recording medium and is in parallel with the surface of the recording medium. In addition, a “lateral direction” refers to a direction perpendicular to the longitudinal direction.
2. Description of the Related Art
Hitherto, image forming apparatuses for forming multicolored images by electrophotographic methods have been proposed in which a plurality of developing cartridges for accommodating different-colored developers (toners) are arranged on a rotary selection mechanism (developing rotary) with respect to a photoconductive drum, which is an electrophotographic photosensitive member, a developing cartridge having a toner of a predetermined color accommodated therein is opposed to the photoconductive drum to effect developing, the developed image is transferred to a recording medium, and the developing and transferring operations are effected for each color to obtain the multicolored image. The developing cartridges are removably attached to the image forming apparatus main body so as to facilitate maintenance by a user.
Such a developing cartridge is formed by combining a developing frame for supporting developing members, such as a developing roller, a developing blade for controlling the thickness of toner coated on the developing roller, and a coating roller for applying the toner to the developing roller, and a toner frame having the toner accommodated therein into a cartridge so as to allow a reduction in size thereof.
In the above described developing cartridge, it is common for a supporting plate of the developing blade to be increased in its degree of straightness and flatness so that the developing blade (control member) for controlling the thickness of a developer on the developing roller (developer carrier) abuts equally against the developing roller along its length.
It is also common for both ends of the developing plate to be fixed by small screws so that the developing blade does not move with respect to a developing case.
In addition, a process cartridge has been proposed incorporating therein the developing device as the developing member.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a developing device and a process cartridge, each including a control member for reducing variations in an abutting force against a developer carrier. The control member controls the thickness of the developer on the developer carrier, as described above.
It is another object of the present invention to provide a developing device and a process cartridge in which a difference in abutting pressure of the developing blade on the developing roller may not be created by a flexure, etc., of the developing blade between the center and the end portion in the longitudinal direction of the developing blade, resulting in unevenness of image density.
It is a still another object of the present invention to provide a developing device including a developer carrier for carrying a developer; and a control member for controlling the thickness of the developer on the developer carrier, the control member including an abutting member abutting against a reference plane of a developing device main body; an elastic member overlapping the abutting member, the elastic member being urged toward the developer carrier, the width in the center portion of overlapped portions of the elastic member and the abutting member being wider than that in both ends thereof; and an overlap member overlapping the elastic member.
It is a further object of the present invention to provide a process cartridge including an image carrier; a developer carrier for carrying a developer; and a control member for controlling the thickness of the developer on the developer carrier, the control member including an abutting member abutting against a reference plane of a developing device main body; an elastic member overlapping the abutting member, the elastic member being urged toward the developer carrier, the width in the center portion of overlapped portions of the elastic member and the abutting member being wider than that in both ends thereof; and an overlap member overlapping the elastic member.
Further objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1
is a vertical section of an electrophotographic image forming apparatus;
FIG. 2
is a sectional view of a rotary unit perpendicular to the axis thereof;
FIG. 3
is a sectional view of a rotary unit perpendicular to the axis thereof;
FIG. 4
is a vertical sectional view of a yellow developing cartridge;
FIG. 5
is a vertical sectional view of a black developing cartridge;
FIG. 6
is a perspective view of a developing cartridge in a state where a shutter is opened;
FIG. 7
is a perspective view of the developing cartridge in a state where the shutter is closed;
FIG. 8
is an exploded view in perspective of a developing cartridge schematically showing the vicinity of the shutter;
FIG. 9
is a side view of a non-drive side of the developing cartridge in a state where the shutter is closed;
FIG. 10
is a side view of a drive side of the developing cartridge in a state where the shutter is closed;
FIG. 11
is a side view of the non-drive side of the developing cartridge in a state where the shutter is opened;
FIG. 12
is a side view of the drive side of the developing cartridge in a state where the shutter is opened;
FIG. 13
is a perspective view of a developing cartridge attachment section of the rotary unit on the non-drive side;
FIG. 14
is a perspective view of the developing cartridge attachment section of the rotary unit on the drive side;
FIG. 15
is a sectional view of a rotary unit perpendicular to the axis thereof showing an operation for attaching the developing cartridge to the rotary unit;
FIG. 16
is a sectional view of a rotary unit perpendicular to the axis thereof showing the operation for attaching the developing cartridge to the rotary unit;
FIG. 17
is a sectional view of a rotary unit perpendicular to the axis thereof showing the operation for attaching the developing cartridge to the rotary unit;
FIG. 18
is a sectional view of a rotary unit perpendicular to the axis thereof showing an operation for attaching the developing cartridge to the rotary unit;
FIG. 19
is a sectional view of a rotary unit perpendicular to the axis thereof showing the operation for attaching the developing cartridge to the rotary unit;
FIG. 20
is a side view showing the relationship between a guide and a positioning member of the developing cartridge;
FIG. 21
is a plan view showing a driving device of the developing cartridge;
FIG. 22
is a side view showing the driving device of the developing cartridge;
FIG. 23
is a side view showing a preferred arrangement of driving members of the developing cartridge;
FIG. 24
is a side view of a preferred arrangement of driving members of the developing cartridge;
FIG. 25
is a perspective view of the shutter;
FIG. 26
is a plan view showing attachment of the developing cartridge to the rotary unit;
FIG. 27
is a perspective view of a developing member-supporting frame;
FIG. 28
is a side view of the developing member-supporting frame;
FIG. 29
is a perspective view of an end of the developing member-supporting frame;
FIG. 30
is a perspective view of a toner frame;
FIG. 31
is a horizontal sectional view of the toner frame;
FIG. 32
is a perspective view of the non-drive side of the developing cartridge as seen from a lower angle;
FIG. 33
is a side view showing one longitudinal end of the developing cartridge;
FIG. 34
is a perspective view showing a coupling frame of the developing cartridge;
FIG. 35
is a perspective view of a side cover on the non-drive side;
FIG. 36
is an exploded perspective view showing a structure of a developing blade;
FIG. 37
is a vertical section showing a structure of a developing blade.
FIG. 38
is a transverse cross section showing a structure of the developing blade;
FIG. 39
is a vertical section showing a structure of the developing blade;
FIG. 40
is a plan view showing a support plate;
FIG. 41
is a transverse cross section showing a structure of the developing blade; and
FIG. 42
is a vertical section of an electrophotographic image forming apparatus having a process cartridge attached thereto.
DESCRIPTION OF THE PREFERRED EMBODIMENT
A developing cartridge in accordance with embodiments of the present invention, and an electrophotographic image forming apparatus (hereinafter, referred to as “an image forming apparatus”) using the cartridge will now be described.
In the following description, a “longitudinal direction” refers to a direction that is perpendicular to a conveyance direction of a recording medium and is in parallel with the surface of the recording medium.
First Embodiment
FIGS. 1
to
3
illustrate a configuration of an image forming apparatus;
FIGS. 4 and 5
are vertical sectional views of a developing cartridge;
FIGS. 6
to
8
are perspective views of the developing cartridge; and
FIGS. 9
to
14
illustrate a mounting configuration of the developing cartridge. In
FIGS. 2
,
3
, and
15
to
19
, dotted lines are employed as imaginary lines.
The overall configuration of the image forming apparatus will first be described, and then the configuration of the developing cartridge will be described.
(Image Forming Apparatus)
First, a schematic configuration of the image forming apparatus according to this embodiment will be described.
FIG. 1
is a side view of a laser beam printer that is an example of the image forming apparatus for forming a color image by the electrophotographic method. The surface of a drum-shaped electrophotographic photosensitive member (hereinafter, referred to as “a photoconductive drum”)
1
is uniformly charged by charging unit
2
. Then, a laser beam corresponding to image information is applied from an exposure device
3
onto the photoconductive drum
1
to form a latent image, and the latent image is developed by four developing cartridges Dm, Dc, Dy, and Db (referred to collectively as D). The developed images formed on the photoconductive drum
1
are sequentially transferred to a belt-shaped intermediate transfer unit
4
one over another to form a color image. The color image is transferred by a transfer unit
6
to a recording medium P (such as a recording paper and an OHP sheet) that is conveyed by a conveyer unit
5
from a feed section. The recording medium P is conveyed to a fixing unit
7
to fix the color image, and is then discharged to a discharge section
8
formed on the top of the apparatus.
Configurations of each of the above components will now be specifically described.
First, the photoconductive drum
1
is integrally formed with a box-like frame
9
a
of a cleaning device
9
for removing a developer (hereinafter, referred to as a “toner”) remaining on the photoconductive drum after a toner image has been transferred to the intermediate transfer unit
4
, as a process cartridge U. The process cartridge U is removably attached to an image forming apparatus main body
30
, and can be replaced by a user in accordance with the service life of the photoconductive drum
1
.
The photoconductive drum
1
is formed by coating an aluminum cylinder of about 50 mm in diameter with an organic photoconductive layer, and is rotatably supported by the frame
9
a
of the cleaning device
9
which also serves as a holder for the photoconductive drum
1
. A cleaning blade
9
b
for scraping off the toner remaining on the photoconductive drum
1
, and the charging unit
2
are disposed on the periphery of the photoconductive drum
1
. Accordingly, in this embodiment, the photoconductive drum
1
, the cleaning device
9
, and the charging unit
2
are made into the process cartridge U that is attachable to and detachable from the apparatus main body
30
.
In addition, the photoconductive drum
1
is rotated counterclockwise in
FIG. 1
, responsive to the image forming operation, by transmitting a driving force of a driving motor
24
M (see FIG.
21
).
The charging means
2
in this embodiment employs a so-called “contact charging method”, and contacts the surface of the photoconductive drum
1
to apply voltage to a rotating conductive roller, thereby uniformly charging the surface of the photoconductive drum
1
.
The exposure means
3
for exposing the charged photoconductive drum
1
includes a polygon mirror
3
a
, a scanner motor
3
b
, an image forming lens
3
c
, and a reflecting mirror
3
d
. When an image signal is transmitted to a laser diode (not shown), the laser diode applies image light responsive to the image signal to the polygon mirror
3
a
. The polygon mirror
3
a
is rotated at a high speed by the scanner motor
3
b
, and the image light reflected from the mirror
3
a
selectively exposes the surface of the constant-speed-rotating photoconductive drum
1
through the image forming lens
3
c
and the reflecting mirror
3
d
to form a latent image.
The latent image is developed by the developing cartridge D for each color. The configuration of the developing cartridge will be described later.
The toner image developed by the developing cartridge D is transferred to the intermediate transfer unit
4
. The intermediate transfer unit
4
, also serving as a second image carrier, secondarily and collectively transfers a plurality of toner images, which are primarily transferred sequentially one over another from the photoconductive drum
1
, to the recording medium P. The intermediate transfer unit
4
includes an intermediate transfer belt
4
a
running in the direction of the arrow R
4
. In this embodiment, the intermediate transfer belt
4
a
has a length of about 440 mm, and is looped over a driving roller
4
b
, a secondary opposite roller
4
c
, and a follower roller
4
d
. A presser roller
4
j
is provided in the vicinity of the follower roller
4
d
. The presser roller
4
j
retracts to be located in a position where it presses the intermediate transfer belt
4
a
to the photoconductive drum
1
and the intermediate transfer belt
4
a
moves away from the photoconductive drum
1
. The intermediate transfer belt
4
a
runs in the direction of the arrow R
4
by the rotation of the driving roller
4
b
. In addition, a cleaning unit
4
e
is provided at a predetermined position outside the intermediate transfer belt
4
a
so as to be brought into contact with and be separated from the surface of the intermediate transfer belt
4
a
. The cleaning unit
4
e
removes the toner remaining on the transfer belt after secondary transfer to the recording medium P. The cleaning unit
4
e
brings a charging roller
4
f
into abutment with the intermediate transfer belt
4
a
to apply a charge to the toner which is opposite to the charge for transferring. The toner that has received the opposite charge is electrostatically allowed to adhere on the photoconductive drum
1
, and is then recovered by the cleaning device
9
for the photoconductive drum
1
. A method for cleaning the intermediate transfer belt
4
a
is not limited to the above electrostatic cleaning method. A mechanical cleaning method, such as a blade cleaning or a fur brush cleaning method, or a combination of these methods may be employed.
The toner remaining on the surface of the photoconductive drum
1
after the toner image has been transferred to the intermediate transfer unit
4
is removed by the cleaning device
9
. The cleaning device
9
scrapes off the toner by the cleaning blade
9
b
abutted against the surface of the photoconductive drum
1
to store the removed toner in a waste toner container
9
c
. The waste toner container
9
c
is formed by the frame
9
a
. The amount of waste toner to be stored in the waste toner container
9
c
is set so as not to fill the waste toner container
9
c
before the expiration of the service life of the photoconductive drum
1
, and the waste toner in the waste toner container
9
c
is removed together with the process cartridge U upon expiration of the service life of the photoconductive drum
1
.
In this embodiment, the transfer unit
6
for transferring the toner images that are successively transferred to the intermediate transfer unit
4
to the recording medium P is constructed of a transfer roller. The transfer roller
6
is formed by winding a medium-resistance-foaming elastic member around a metal shaft, and is provided so as to move in the up and down directions in FIG.
1
.
The transfer roller
6
is located downward as shown by the solid line in
FIG. 1
so as to be separated from the intermediate transfer unit
4
during the formation of four-colored toner images on the intermediate transfer unit
4
, i.e., during the rotation of the intermediate transfer unit
4
a plurality of times, so as not to disturb the images.
After the toner images have been successively transferred onto the intermediate transfer unit
4
to form a color image, the transfer roller
6
is moved to the upper position by a cam (not shown) as shown by the single-dot chain line in FIG.
1
. This allows the transfer roller
6
to be pressed onto the intermediate transfer unit
4
at a predetermined pressure via the recording medium P. At the same time, a bias voltage is applied to the transfer roller
6
, and the toner images on the intermediate transfer unit
4
are transferred to the recording medium P.
As shown in
FIG. 1
, the conveyer unit
5
for conveying the recording medium P consists of a paper feeding cassette
5
a
containing therein a plurality of recording media P, a pickup roller
5
b
, a feed roller
5
c
1
, a retarding roller
5
c
2
for preventing overlap-feeding of the recording medium P, conveyer roller pair
5
d
, register roller pair
5
e
, discharge roller pair
5
f
, and a conveyer guide
5
g
1
.
When forming an image, the pickup roller
5
b
is rotationally driven in response to the image forming operation to individually feed the recording media P stored in the paper feeding cassette
5
a
. The recording medium P fed from the paper feeding cassette
5
a
is guided by the conveyer guide
5
g
to reach the register roller pair
5
e
via the conveyer roller pair
5
d
. During the image forming operation, the register roller pair
5
e
performs a nonrotary operation for allowing the recording medium P to be on standby, and a rotary operation for conveying the recording medium P toward the intermediate transfer unit
4
at a predetermined sequence, and then performs registration of the image and the recording medium during the next transfer step, whereby the color image is transferred onto the recording medium P by the above-mentioned transfer roller
6
.
The recording medium P having the color image transferred thereon is conveyed to the fixing unit
7
, and a toner image is fixed thereon. The fixing unit
7
consists of a fixing roller
7
a
for applying heat to the recording medium P and a presser roller
7
b
for pressing the recording medium P into contact with the fixing roller
7
a
. These rollers
7
a
and
7
b
are hollow rollers including therein heaters, respectively, and are rotationally driven. The rollers
7
a
and
7
b
convey the recording medium P while applying heat and pressure thereto, whereby the toner image is fixed to the recording medium P.
The recording medium P having the toner image fixed thereto is discharged by the discharge roller pair
5
f
to the discharge section
8
.
(Developing Cartridge)
The configuration of the developing cartridge for developing a latent image formed on the photoconductive drum
1
will now be described.
The image forming apparatus of this embodiment includes four developing cartridges D (Dm, Dc, Dy, and Db) in order to enable development of magenta, cyan, yellow, and black, respectively. The developing cartridges D are removably attached to a rotary unit
11
that rotates about a central shaft
10
, as shown in
FIGS. 1
to
3
. In forming images, each developing cartridge D rotationally moves about the central shaft
10
while being held by the rotary unit
11
, and stops at a position where the developing cartridge D containing therein a predetermined color toner is opposed to the photoconductive drum. Further, after a developing roller (developer carrier) described hereinbelow has been positioned to oppose the photoconductive drum
1
with a narrow clearance (about 300 μm), each developing cartridge D supplies a toner in response to an electrostatic latent image on the photoconductive drum
1
to develop the latent image.
When forming a color image, the rotary unit
11
rotates at each rotation of the intermediate transfer unit
4
to perform development operation in the order of a magenta developing cartridge Dm containing magenta toner, a cyan developing cartridge Dc containing cyan toner, a yellow developing cartridge Dy containing yellow toner, and a black developing cartridge Db containing black toner. The black toner is a magnetic toner, and other color toners are nonmagnetic toners.
FIG. 4
shows a state where the developing cartridge D (for example, the yellow developing cartridge Dy) is standing still at a development position opposed to the photoconductive drum
1
. The developing cartridge D includes a developing roller
12
that is a toner carrier for supplying a toner to the photoconductive drum
1
, and a toner storage section
63
a
for storing the toner, a cartridge frame
63
combining a plurality of frames, and a shutter
64
that can open and close an opening provided in the cartridge
63
to expose the developing roller
12
. In addition, a toner-feeding member
15
is provided inside the toner storage section
63
a
. A toner seal
27
is attached to the developing cartridge D to prevent leakage of the toner stored in the toner storage section
63
a
. The user tears off the toner seal
27
to open the toner storage section
63
a
before attaching the developing cartridge D to the apparatus main body
30
, whereby the toner in the toner storage section
63
a
can be supplied to the developing roller
12
.
Upon receipt of a driving force from the apparatus main body
30
, the toner-feeding member
15
rotates to feed the toner in the toner storage section
63
a
to the developing roller
12
. The developing roller
12
is a rotatable aluminum roller, and a developing blade
16
is pressed into contact with the peripheral surface of the developing roller
12
. Therefore, when the developing roller
12
rotates in a clockwise direction in
FIG. 4
, the toner is coated in a thin layer on the peripheral surface thereof, and the toner is frictionally statically charged.
A development bias voltage supplied from the apparatus main body
30
is applied to the developing roller
12
that is opposed to the photoconductive drum
1
having the latent image formed thereon, whereby a toner image can be formed on the photoconductive drum
1
in response to the latent image.
The above-mentioned configuration and development process are identical to those of the magenta developing cartridge Dm, the cyan developing cartridge Dc, the yellow developing cartridge Dy, and the black developing cartridge Db. In addition, the developing roller
12
of each developing cartridge D is connected to a high-voltage power supply for each color development and to a drive source provided in the apparatus main body
30
when each developing cartridge D is moved to the development position. A development bias voltage is sequentially and selectively applied to each developing cartridge D, and a driving force is transmitted to each developing cartridge D to rotate the developing roller
12
.
The magenta developing cartridge Dm, the cyan developing cartridge Dc, and the yellow developing cartridge Dy shown in
FIG. 4
have the same structure. That is, these developing cartridges Dm, Dc, and Dy include an application roller
19
, which has a peripheral surface moving in the direction opposite to that of the developing roller
12
, provided in a developing member-supporting frame
63
A of the cartridge frame
63
.
The black developing cartridge Db shown in
FIG. 5
does not include the application roller. The arrangement is such that the toner is adhered onto the developing roller
12
by a magnetic force and an adhering force of a magnet (not shown) incorporated into the developing roller
12
, the thickness of the toner layer is controlled by the developing blade
16
contacting the peripheral surface of the developing roller
12
, and the toner is frictionally statically charged.
(Attachment of Developing Cartridge to Apparatus Main body)
A configuration for the attachment of the developing cartridge D to the image forming apparatus main body
30
will now be described.
As shown in
FIGS. 1
,
13
, and
14
, an insertion opening
17
having the width longer than the length of the developing cartridge D is formed in a predetermined position of the apparatus main body
30
, and a cover
18
is mounted on the insertion opening
17
in such a manner that it can be opened and closed. The insertion opening
17
is normally closed by the cover
18
.
In addition, the apparatus main body
30
is provided with a developing device replacement switch (not shown). When the user pushes the switch for the replacement of the developing cartridge D by reason of consumption of the toner, etc., the rotary unit
11
rotates about the central shaft
10
, and one of the developing cartridges D to be replaced is moved to the insertion opening
17
.
When the user opens the cover
18
, a guide
59
constituting attachment means of the developing cartridge D is provided on one side of the apparatus main body
30
, as shown in FIG.
14
. Four guides
59
are equally provided circumferentially on the rotary unit
11
. On the other hand, a shutter
64
of the developing cartridge D is provided with a guide section
70
, as shown in
FIGS. 6
,
7
,
8
, and
10
. The user can attach the developing cartridge D to the apparatus main body
30
by inserting the guide section
70
along the guide
59
. The guide section
70
is provided longitudinally on only one side (the direction of the rotation axis of the developing roller
12
) of the developing cartridge D. Accordingly, the guide
59
is also provided on only one inner wall surface
11
a
of the rotary unit
11
. In addition, circular ribs
26
a
and
59
e
are provided longitudinally on both inner wall surfaces
11
a
and
11
e
of the rotary unit
11
, and projections
63
c
and
63
g
(see
FIGS. 9
to
12
), which are fitted into the circular ribs
26
a
and
59
e
, are provided longitudinally at both side surfaces of the developing cartridge D on the same center line parallel to the developing roller
12
.
The developing cartridge D is inserted into the rotary unit
11
in a direction perpendicular to the longitudinal direction of the developing roller
12
by being gripped by hand at its grip
63
e
(see
FIG. 7
) with the developing roller
12
being directed forward (the direction in which the developing roller
12
can oppose the photoconductive drum
1
after the attachment).
After the developing cartridge D has been attached to the apparatus main body
30
, the user rotates the developing cartridge D about the projections
63
c
and
63
g
, whereby the shutter
64
is opened, the developing roller
12
is exposed from the cartridge frame
63
to oppose the photoconductive drum
1
, and the developing cartridge D is attached in a developable state.
The developing cartridge D attached to the attachment position of the rotary unit
11
is urged longitudinally by a spherical presser member
26
b
that is located at the circular rib
26
a
provided on one inner wall surface
11
e
of the rotary unit
11
(the developing cartridge D is urged toward a driving force receiver member
22
). The presser member
26
b
is elastically and longitudinally urged by a spring (not shown). The developing cartridge D is urged to the driving side. Accordingly, the developing cartridge D is attached to the rotary unit
11
(the apparatus main body
30
) longitudinally of the developing roller
12
with reference to the side of the driving force receiver member
22
.
The configuration of the developing cartridge D will now be described in detail with reference mainly to
FIGS. 8
to
12
.
FIG. 8
is a perspective view of the developing cartridge D in a state where the shutter
64
, etc. are removed.
FIGS. 9 and 10
show both sides of the developing cartridge D in a state where the shutter
64
is closed, and
FIGS. 11 and 12
show both sides of the developing cartridge D in a state where the shutter
64
is opened.
As shown in
FIG. 8
, an opening
63
b
is formed longitudinally in the cartridge frame
63
of the developing cartridge D, and the developing roller
12
is mounted in the cartridge frame
63
so as to be exposed from the opening
63
b
. The projection
63
c
is integrally formed with the cartridge frame
63
in substantially a center of one side surface
63
h
of the cartridge frame
63
. The projection
63
c
is formed in a cylindrical shape, and serves as a guide when the developing cartridge D is inserted into the apparatus main body
30
and as a center of rotation when the developing cartridge D is attached to and detached from the apparatus main body
30
. The projection
63
c
is formed in a cylindrical shape.
The projection
63
g
is removably mounted in substantially a center of the other side surface
63
i
(
FIG. 9
) of the cartridge frame
63
(
FIG. 8
shows a removed state). The projection
63
g
is mounted on the cartridge frame
63
by inserting an insertion portion
63
g
1
into a hole (not shown) formed in the side surface
63
i
. The insertion portion
63
g
1
has an inverted shaft/post part (not shown) formed at its terminal end, and the inverted shaft/post part engages with the cartridge frame
63
, whereby the projection
63
g
is mounted to the cartridge frame
63
. In addition, when the developing cartridge D is attached to the attachment position of the rotary unit
11
, a terminal end face
63
g
2
of the projection
63
g
is pressed by the presser member
26
b
. Accordingly, the developing cartridge D is pressed toward the side surface
63
h
(in the direction indicated by the arrow Q in FIG.
8
). The developing cartridge D is attached to the rotary unit
11
(apparatus main body
30
) with reference to the side surface
63
h
provided with the driving force receiver member
22
.
Spacer rollers
12
a
and
12
b
, each having a radius larger than that of the developing roller
12
by a development clearance, are fitted to both ends of the developing roller
12
. Accordingly, the spacer rollers
12
a
and
12
b
are pressed onto the peripheral surface of the photoconductive drum
1
by a biasing force of a biasing means
25
(see
FIG. 24
) or a helical compression spring
10
b
(see
FIG. 3
) biasing a sliding member
10
a
at a development position, whereby a predetermined clearance is maintained between the developing roller
12
and the photoconductive drum
1
.
The developing blade
16
made of rubber, etc., is mounted on the cartridge frame
63
via a blade-supporting sheet metal
16
a
secured by small screws
16
b
1
. A configuration of the developing blade
16
will be described later in detail.
A locking member
71
is mounted on the side surface
63
h
of the developing cartridge D (
FIG. 8
shows a removed state thereof). The locking member
71
includes an engagement section
71
b
engaging with an engagement recess
64
t
provided in a side wall
64
e
of the shutter
64
, a support section
71
a
for supporting the engagement section
71
b
, and mounting sections
71
c
and
71
d
attached on the side surface
63
h
. Mounting holes
63
j
1
and
63
i
2
are provided in the side surface
63
h
into which the mounting sections
71
c
and
71
d
are inserted. The locking member
71
is an integrally molded article which may be made of plastic. In the attachment process of the developing cartridge D, an arm section
71
g
of the locking member
71
comes into contact with a fixture section provided in the apparatus main body
30
, whereby the support section
71
a
flexes and the engagement section
71
b
is disengaged from the engagement recess
64
t
to unlock the shutter
64
.
A hemispherical projection
63
d
is provided only on the side surface
63
h
of the cartridge frame
63
, as shown in
FIGS. 2
,
3
,
6
,
7
,
8
,
10
, and
12
. A hole
64
u
into which the projection
63
d
can be fitted is formed in the corresponding position of the shutter
64
. Accordingly, since the projection
63
d
is fitted into the hole
64
u
when the shutter
64
is closed, the cartridge frame
63
does not rotate to an unstable position with respect to the shutter
64
even if the shutter
64
is unlocked.
In addition, positioning bosses
63
m
(
63
m
1
and
63
m
2
), and spring receivers
63
k
(
63
k
1
and
63
k
2
) described hereinbelow are projected on the side surfaces
63
h
and
63
i
of the cartridge frame
63
, respectively.
A toner seal grip
73
shown in
FIG. 9
is used when the user tears off the toner seal
27
.
(Shutter)
As shown in
FIG. 25
, round holes
64
a
are formed longitudinally in both side walls
64
e
and
64
f
of the shutter
64
, and the projections
63
c
and
63
g
are fitted into the round holes
64
a
, whereby the shutter
64
is rotatably mounted on the cartridge frame
63
. A shutter cover section
64
g
for covering the opening
63
b
of the cartridge frame
63
forms a part of a cylinder having the center line passing through the center of the round holes
64
a
. When the shutter
64
is closed, as shown in
FIG. 7
, the opening
63
b
is closed and the developing roller
12
is covered with the shutter
64
. Since the shutter
64
is closed when the developing cartridge D is removed from the apparatus main body
30
, dust or the like does not adhere to the developing roller
12
and the developing roller
12
is not damaged. In addition, no foreign matter enters into the developing cartridge D.
The support section
71
a
of the locking member
71
can be elastically deformed by being supported only at the side of the mounting sections
71
c
and
71
d
by forming a slit
71
f
, as shown in
FIG. 8
, and has the engagement section
71
b
and the unlocking aluminum arm section
71
g
formed at a terminal end thereof. The mounting section
71
c
has a longitudinal cylindrical shape, and is fitted into the mounting hole
63
j
1
. The two mounting sections
71
d
provided around the mounting section
71
c
are square dowels projecting longitudinally, each having an inverted shaft/post portion (not shown). These mounting sections
71
d
are fitted into the square mounting holes
63
j
2
formed around the mounting hole
63
j
1
, whereby the locking member
71
is mounted to the side surface
63
h
of the cartridge frame
63
.
When the shutter
64
is opened, the terminal end of the engagement section
71
b
is located on a cam edge
64
n
having a circular section coaxial with the round hole
64
a
of the side wall
64
e
of the shutter
64
, as shown in FIG.
12
. When the shutter
64
is closed, the engagement section
71
b
engages with the engagement recess
64
t
provided on the cam edge
64
n
, whereby the shutter
64
is locked in a closed state so as not to open accidentally. When the developing cartridge D is attached to the apparatus main body
30
, the shutter
64
is automatically unlocked and opened.
(Attachment of Developing Cartridge)
A step for attaching the developing cartridge D to the apparatus main body
30
, and a step for positioning the developing cartridge D in the apparatus main body
30
will now be specifically described with reference to
FIGS. 13
to
19
.
As shown in
FIG. 14
, the guide
59
provided on one inner wall surface
11
a
of the rotary unit
11
includes a guide insertion section
59
b
having inclined parts
59
a
that are inclined to open upward, a projection insertion section
59
d
having substantially parallel linear ribs
59
c
, a fitting section
59
f
that serves as a support member having circular ribs
59
e
, and a guide insertion section
59
h
having substantially parallel linear ribs
59
g
extending from the fitting section
59
f
. The guide
26
is provided on the other inner wall surface
11
e.
As shown in
FIGS. 13 and 14
, the central shaft
10
has the sliding members
10
a
that are provided near the inner wall surface
11
e
of a flange
11
f
of one end of the rotary unit
11
and near the inner wall surface
11
a
of a flange
11
g
of the other end of the rotary unit
11
so as to move radially of the central shaft
10
. As shown in
FIG. 15
, the sliding member
10
a
is movably fitted to guide sections
10
d
that are provided symmetrically about a straight line connecting substantially the center of the central shaft
10
and the center of the circular ribs
59
e
in the attachment position of the developing cartridge D to be substantially in parallel with the straight line. A slot
10
a
1
is formed in the sliding member
10
a
in parallel with the guide sections
10
d
, and a pin shaft
10
c
fixed to the central shaft
10
is fitted to the slot
10
a
1
so that the sliding member
10
a
is located at a position to form a continuous single circle on the outer periphery of the central shaft
10
by its front-end circular face
10
e
, as shown in
FIG. 15
, and at a position to form a recess
10
f
having the front-end circular face
10
e
as a bottom in the central shaft
10
, as shown in FIG.
18
. The helical compression spring
10
b
is provided in a compressed manner between the bottom of the guide sections
10
d
and a rear end of the sliding member
10
a
. The width (the size perpendicular to a straight line connecting the center of the central shaft
10
and the center of the circular ribs
59
e
, and parallel with the plane of
FIG. 18
) of the front-end circular face
10
e
of the sliding member
10
a
is set such that the positioning bosses
63
m
1
and
63
m
2
of the developing cartridge D are located on the front-end circular face
10
e
with the developing cartridge D being attached to an attachment section by an operation described hereinbelow.
In inserting the developing cartridge D into the apparatus main body
30
, the user first inserts the guide section
70
provided on the shutter
64
and the projection
63
c
provided on a toner frame
63
B into the guide insertion section
59
b
(see FIG.
15
).
When the developing cartridge D is further inserted, the projection
63
c
enters into the linear portion of the projection insertion section
59
d
, as shown in FIG.
16
. The projection
63
c
has cut sections
63
c
1
, each formed by partially and linearly cutting a cylinder at an angle parallel to each of the linear ribs
59
c
so as to have a flat width thereacross, and the two linear ribs
59
c
into which the cut sections
63
c
1
are fitted have a width W
1
shown in FIG.
14
through which the cut sections
63
c
1
can pass only in the direction of parallel movement thereof. Therefore, the cut sections
63
c
1
are fitted and inserted between the linear ribs
59
c
, whereby the developing cartridge D is inserted into the apparatus main body
30
while maintaining a predetermined angle.
When the projection
63
c
is inserted to reach the circular ribs
59
e
, as shown in
FIG. 17
, a terminal end of one of the inclined parts
59
a
abuts against the arm section
71
g
of the locking member
71
locking the shutter
64
to push it upward, as shown in FIG.
17
. This allows the support section
71
a
to be elastically deformed, and the engagement section
71
b
comes out of the engagement recess
64
t
, so that the shutter
64
is unlocked. (That is, in this embodiment, the inclined sections
59
a
also have a function of unlocking the locking member
71
). In this state, the shutter
64
can be rotated with respect to the cartridge frame
63
. In addition, each circular rib
59
e
has a radius such that the projection
63
c
can rotate therein, whereby the developing cartridge D can be rotated about the projection
63
c.
On the other hand, the projection
63
g
provided on the other side surface
63
i
of the developing cartridge D is guided by an inclined section
26
c
of the guide
26
shown in
FIG. 13
to enter a guide insertion section
26
d
. When the developing cartridge D is further inserted, as in the case of the projection
63
c
, cut sections
63
g
3
(see
FIG. 8
) oppose each other in parallel, and are fitted and inserted between two linear ribs
26
e
, so that the developing cartridge D is inserted into the apparatus main body
30
while maintaining a predetermined angle. The projection
63
g
is inserted to reach the circular rib
26
a
. The circular rib
26
a
has a radius so that the projection
63
g
can rotate therein. Accordingly, the developing cartridge D can be rotatably supported about the projections
63
c
and
63
g
by the rotary unit
11
with the projection
63
c
on one side end of the cartridge frame
63
supported by the circular ribs
59
c
, and with the projection
63
g
on the other side end of the cartridge frame
63
supported by the circular rib
26
a.
In the attachment of the developing cartridge D to the rotary unit
11
, a configuration for securely attaching the developing cartridges Dm, Dc, Dy, and Db to cartridge attachment sections
14
m
,
14
c
,
14
y
, and
14
b
, respectively, will be described later.
When the user manually pushes the grip
63
e
of the cartridge frame
63
in the state shown in
FIG. 17
, the shutter
64
is fixed because the guide section
70
is fitted to a guide section-insertion section
59
h
. The projection
63
c
of the cartridge frame
63
, however, can be rotated within the circular ribs
59
e
, and the projection
63
g
can be rotated within the circular rib
26
a
, so that the hemispherical projection
63
d
rotates to a predetermined position (in the direction shown by the arrow X in
FIG. 17
) passing over the hole
64
u
of the shutter
64
. As mentioned above, in this embodiment, since the shutter
64
is provided with the guide section
70
, the cartridge frame
63
can be easily rotated with the shutter
64
fixed. When the cartridge frame
63
is rotated to a predetermined position, it is positioned by positioning means described hereinbelow and the developing cartridge D is attached.
In rotating the developing cartridge D in the state shown in
FIG. 17
in the direction of the arrow X, the positioning bosses
63
m
(
63
m
1
and
63
m
2
) provided on both longitudinal side surfaces
63
h
and
63
i
of the cartridge frame
63
press the sliding member
10
a
that is movably fitted between guide sections
10
d
provided on both sides of the central axis
10
and biased by the helical compression spring
10
b
over the diameter of the central axis
10
downward (see FIG.
18
). The pin shaft
10
c
fixed to the central shaft
10
is fitted into the slot
10
a
1
, so that the sliding member
10
a
can slide in a constrained manner. That is, the front-end circular face
10
e
of the sliding member
10
a
is flush with the outer periphery of the central shaft
10
with the pin shaft
10
c
abutting against one end of the slot
10
a
1
. When the cartridge
63
is further rotated, as shown in
FIG. 19
, the spring receivers
63
k
(
63
k
1
and
63
k
2
) provided longitudinally on both side surfaces
63
h
and
63
i
are pressed by helical compression spring
11
d
provided on both ends of the rotary unit
11
. This applies a rotating force in the direction shown by the arrow Y in
FIG. 19
to the cartridge frame
63
. Both of the positioning bosses
63
m
, however, abut against the sliding member
10
a
, and the cartridge frame
63
is stable at an attachment position shown in FIG.
19
.
That is, the developing cartridge D is attached to a predetermined attachment position of the rotary unit
11
. Guide sections
11
j
are provided on the rotary unit
11
to guide the bosses
63
m.
With the described arrangement, the shutter
64
is opened with respect to the cartridge frame
63
to expose the developing roller
12
so as to oppose the photoconductive drum
1
. The user can recognize a rotation start position of the developing cartridge D by a clicking sensation made by the hemispherical projection
63
d
when coming out of the hole
64
u.
Since the diameter of a cylindrical part
63
c
2
of the projection
63
c
is longer than the distance between the cut sections
63
c
1
, the projection
63
c
does not come out between the linear ribs
59
c
in a state where it is rotated at the position of the circular ribs
59
e.
Similarly, since the diameter of a cylindrical part
63
g
4
of the projection
63
g
is longer than the distance between the cut sections
63
g
3
, the projection
63
g
does not come out between the linear ribs
26
e
in a state where it is rotated at the position of the circular rib
26
a.
On the other hand, in detaching the developing cartridge D from the apparatus main body
30
, the user rotates the cartridge frame
63
in the opposite direction, whereby the cut sections
63
c
1
are in parallel with the linear ribs
59
c
and the shutter
64
is closed. At this time, the user can recognize a rotation end position (detachment position) of the developing cartridge D by a click sensation made by the hemispherical projection
63
d
when it is fitted into the hole
64
u
. When the developing cartridge D is pulled out of the apparatus main body
30
in this state, the support section
71
a
of the locking member
71
elastically returns, whereby the engagement section
71
b
enters into the engagement recess
64
t
, as shown in FIG.
16
. This allows the shutter
64
to be locked automatically.
As described above, the developing cartridge D is provided with the shutter
64
, thereby preventing dust, etc. from adhering to the developing roller
12
. In addition, the shutter
64
is provided with a locking mechanism, thereby preventing the shutter
64
from being accidentally opened.
The shutter
64
is kept closed when inserting the developing cartridge D into the apparatus main body
30
, so that the developing roller
12
is not damaged in the middle of the insertion. In addition, unlike conventional developing cartridges, no labor is required in which the user manually removes a developing roller-protecting member, etc. before inserting the developing cartridge.
Further, in the attachment of the developing cartridge D to the apparatus main body
30
, the shutter
64
is automatically unlocked, and the shutter
64
is opened and the developing roller
12
opposes the photoconductive drum
1
to complete the attachment only by rotating the developing cartridge D after the insertion thereof. Therefore, attachment operability of the developing cartridge D is improved.
(Positioning of Developing Cartridge)
Positioning of the developing cartridge D will now be described.
The arrangement of the spring receivers
63
k
(
63
k
1
and
63
k
2
) and the positioning bosses
63
m
(
63
m
1
and
63
m
2
) will first be described with reference to FIG.
20
.
While the arrangement on one side surface
63
h
of the cartridge frame
63
will be described in relation to the longitudinal direction of the developing roller
12
, the arrangement is similar to that on the other side surface
63
i.
In this embodiment, the spring receivers
63
k
(
63
k
1
and
63
k
2
), as viewed longitudinally of the developing roller
12
, are arranged within the range of about 110° to 130° with respect to a straight line L
1
connecting the center of rotation M
2
of the developing roller
12
and the center of rotation M
1
of the driving force receiver member
22
about the center of rotation M
1
.
More specifically, the spring receiver
63
k
1
(
63
k
2
) is arranged so that an angle formed between a straight line L
1
connecting the center of rotation M
2
of the developing roller
12
and the center of rotation M
1
of the driving force receiver member
22
and a straight line L
2
connecting a spring receiver face
63
k
3
(located radially on a plane about the center of rotation M
1
) and the center of rotation M
1
is within the range of about 100° to 130°. In this embodiment, the angle is set to about 115°.
In addition, the bosses
63
m
(
63
m
1
and
63
m
2
) are arranged within the range of about 130° to 150° on the opposite side of the spring bearing
63
k
with respect to the straight line L
1
.
More specifically, the bosses
63
m
(
63
m
1
and
63
m
2
) are arranged so that an angle formed between the straight line L
1
and a straight line L
3
connecting a center
63
m
3
of the bosses
63
m
(
63
m
1
and
63
m
2
) and the center of rotation M
1
is within the range of about 130° to 150°. In this embodiment, the angle is set to about 140°.
By arranging the spring receivers
63
k
(
63
k
1
and
63
k
2
) and the bosses
63
m
(
63
m
1
and
63
m
2
) as described above, the spring receivers
63
k
(
63
k
1
and
63
k
2
) can advantageously receive a resilient force of the helical compression springs
11
d
provided on the rotary unit
11
. In addition, the bosses
63
m
can advantageously abut against the sliding member
10
b
provided on the central shaft
10
. Accordingly, the developing cartridge D can be accurately positioned on the attachment position.
The bosses
63
m
(
63
m
1
and
63
m
2
) project outward by about 2 mm to 5 mm from the side surfaces
63
h
and
63
i
of the cartridge frame
63
. In this embodiment, the bosses
63
m
(
63
m
1
and
63
m
2
) project by about 4 mm.
In addition, the spring receivers
63
k
(
63
k
1
and
63
k
2
) project outward by about 2 mm to 20 mm from the side surfaces
63
h
and
63
i
of the cartridge frame
63
. In this embodiment, the spring receiver
63
k
1
projects by about 10 mm, and the spring receiver
63
k
2
projects by about 6 mm. That is, the amount of projection of the spring receiver
63
k
1
provided on the side of the driving force receiver member
22
is larger than that of the spring receiver
63
k
2
.
(Drive Section of Development Cartridge)
A configuration for the transmission of the driving force from the apparatus main body
30
to the developing cartridge D will now be described.
As shown in
FIGS. 21 and 22
, the driving force receiver member
22
is provided in the cylindrical projection
63
c
for transmitting a rotational driving force from the apparatus main body
30
to the developing roller
12
, and a stepped driving gear
23
a
is integrally formed with the driving force receiver member
22
. A development roller gear
23
b
meshes with a large gear
23
a
1
of the gear
23
a
to rotate the developing roller
12
when the driving force is transmitted to the driving force receiver member
22
. In addition, a small gear
23
a
2
of the gear
23
a
meshes with a large gear
23
c
1
of a stepped idler gear
23
c
, and a small gear
23
c
2
of the stepped idler gear
23
c
meshes with an agitation gear
23
d
integrally molded with a journal
33
(see FIG.
31
), which is a rotation shaft of the toner feeding member
15
, so as to also transmit the rotating force to the toner feeding member
15
. In addition, an application roller gear
23
e
fixed to a rotation shaft
19
a
of the application roller
19
meshes with the small gear
23
a
2
.
The head of the driving force receiver member
22
is formed in the shape of a projected cross rib, and this portion is further formed into a coupling shape so as to be coupled to a drive-transmission member of the apparatus main body
30
described hereinbelow.
On the other hand, as shown in
FIG. 21
, a drive-transmission member
24
for transmitting the driving force from the motor
24
M is provided outside the rotary unit
11
to coaxially oppose the driving force receiver member
22
in a state where the developing cartridge D is attached to the apparatus main body
30
. A transmission mechanism for transmitting a driving force from the motor
24
M to the drive-transmission member
24
is schematically shown by the double-dot chain line. The drive-transmission member
24
is provided so as to move toward the rotation shaft of the driving force receiver member
22
, as shown by the arrow a in
FIG. 21
, and the head thereof is formed into a coupling shape so as to be fitted to the rib of the driving force receiver member
22
. The “coupling shape” refers to a shape formed such that both of the driving force receiver member
22
and the drive-transmission member
24
engage with each other when the drive-transmission member
24
axially moves to the driving force receiver member
22
, and both members
22
and
24
are integrally rotated with each other when one of them is rotated. In this embodiment, four recesses
22
a
are formed in the driving force receiver member
22
, while four projections
24
a
are formed on the drive-transmission member
24
. Therefore, the drive-transmission member
24
is rotated with the projections
24
a
fitted to the recesses
22
a
, whereby the driving force receiver member
22
is rotated.
In the image formation, the arrangement is such that when the attached developing cartridge D is moved to a developing position for the image formation by the rotation of the rotary unit
11
, the drive-transmission member
24
is moved toward the driving force receiver member
22
by a moving mechanism (not shown) so as to be coupled to the driving force receiver member
22
to transmit the driving force to the developing roller
12
, etc. With the described arrangement, the driving force is transmitted to the developing cartridge D always from the same position, and only a driving torque produced by coupling is transmitted even if the stop position of the developing cartridge D is more or less shifted relative to the photoconductive drum
1
, or even if generating lines of the photoconductive drum
1
and the rotary unit
11
deviate from each other. Therefore, it is possible to reduce pitch variations, etc., caused by improper engagement of the gears.
A configuration for stabilizing a pressing force of the developing roller
12
to the photoconductive drum
1
will now be described with reference to
FIGS. 23 and 24
. In these drawings, components performing functions similar to those of the driving members shown in
FIG. 22
are indicated by the same reference numerals, and a description thereof will be omitted.
As described above, the developing cartridge D receives the driving force transmitted from the drive-transmission member
24
provided in the apparatus main body
30
at the development position via the driving force receiver member
22
.
When the developing cartridge D is located at the development position, as shown in
FIG. 23
, if a straight line connecting the center of rotation of the developing cartridge D about the projection
63
c
and the center of rotation of the photoconductive drum
1
is taken as X
1
, and a straight line connecting the center of rotation of the projection
63
c
and the center of rotation of the developing roller
12
is taken as X
2
, the straight line X
2
is located upstream of the straight line X
1
as viewed from the center of rotation of the projection
63
c.
With the described arrangement, the developing cartridge D receives rotation moment in the direction of R, and a force is always exerted on the developing roller
12
in a direction to be urged into the photoconductive drum
1
, and the developing roller
12
is arranged in such a manner as to be urged into the photoconductive drum
1
. Therefore, the developing roller
12
is always stably pressed toward the photoconductive drum
1
, thereby performing stable development. This fact is effective in so-called contact development, but is particularly effective in non-contact development because a stable gap is maintained between the photoconductive drum
1
and the developing roller
12
.
In addition, as shown in
FIG. 24
, in the case where the urging means
25
for urging and fixing the developing cartridge D to the photoconductive drum
1
is provided when the developing cartridge D is located at the development position, if a direction of moment generated by an urging direction Q of the urging means
25
on the developing cartridge D is taken as DM, a straight line connecting the center of rotation of the developing cartridge D and the center of rotation of the photoconductive drum
1
is taken as X
1
, and a straight line connecting the center of rotation of the projection
63
c
and the center of rotation of the developing roller
12
is taken as X
2
, the straight line X
2
is located upstream of the straight line X
1
with respect to the direction of moment DM as viewed from the center of rotation of the projection
63
c
. Such an arrangement may provide advantageous effects similar to the foregoing arrangement. The urging means
25
is located longitudinally at both ends of the developing cartridge D to press a rear portion of the toner storage section
63
a.
(Means for Improving Operability of Developing Cartridge)
The developing cartridges D (Dm, Dc, Dy, and Db) have the same mounting features, such as mounting shapes and dimensions, and can at least be attached to a plurality of cartridge attachment sections
14
(
14
m
,
14
c
,
14
y
, and
14
b
) of the rotary unit
11
. By preventing the developing cartridge, other than that to be attached to one of the cartridge attachment sections
14
of a predetermined color, from being attached to the cartridge attachment section, operability of the user attaching the developing cartridge to the cartridge attachment section can be improved. As shown in
FIGS. 2
,
3
,
13
, and
14
, the rotary unit
11
has disk-like flanges
11
f
and
11
g
formed on both ends thereof, and the center of the flanges
11
f
and
11
g
is supported by the central shaft
10
. The cartridge attachment sections
14
are equally provided circumferentially on the rotary unit
11
. In this embodiment, the four cartridge attachment sections
14
m
,
14
c
,
14
y
, and
14
b
are equally provided circumferentially on the rotary unit
11
so as to be attached to the developing cartridges Dm, Dc, Dy, and Db, respectively.
Partitions
11
m
,
11
c
,
11
y
, and
11
b
for partitioning the cartridge attachment sections
14
are provided between the flanges
11
f
and
11
g
to connect them. The partitions
11
m
,
11
c
,
11
y
, and
11
b
are axially located at different positions of the rotary unit
11
on the cross section shown in
FIGS. 2 and 3
. The partitions
11
m
,
11
c
,
11
y
, and
11
b
have identification parts
11
m
1
,
11
c
1
,
11
y
1
, and
11
b
1
, respectively, provided at their ends near the flange
11
g
(on the side of a driving force receiver section). In
FIGS. 2 and 3
, the rotary unit
11
is cut by a plane perpendicular to the axis at the position of identification part
11
c
1
, and the identification parts
11
y
1
and
11
b
1
are not shown in the drawings. The identification parts
11
m
1
,
11
c
1
,
11
y
1
, and
11
b
1
are axially located at different positions of the rotary unit
11
(see FIG.
26
). The identification parts
11
m
1
,
11
c
1
,
11
y
1
, and
11
b
1
have the same recessed shape cut into the outer peripheral edges of the partitions
11
m
,
11
c
,
11
y
, and
11
b
, respectively.
On the other hand, as shown in
FIGS. 25 and 26
, the shutters
64
(
64
m
,
64
c
,
64
y
,
64
b
) of the developing cartridges D are provided with identification parts
64
M,
64
C,
64
Y, and
64
B, respectively, for identifying respective developing cartridges D (
FIGS. 2 and 3
show the identification part
63
C, and
FIG. 25
shows the identification part
64
B). These identification parts
64
M,
64
C,
64
Y, and
64
B are longitudinally provided at different positions of the cylindrical outer periphery of the shutter cover section
64
g
of the shutters
64
of the developing cartridges D to project from the outer periphery of the shutters
64
(
64
m
,
64
c
,
64
y
,
64
b
). The identification parts
64
M,
64
C,
64
Y, and
64
B are substantially perpendicular to the guide section
70
directed toward substantially the center of the round holes
64
a
formed in the shutters
64
(
64
m
,
64
c
,
64
y
,
64
b
) when the shutters
64
(
64
m
,
64
c
,
64
y
,
64
b
) are seen longitudinally, and the center thereof coincides with the center of the round holes
64
a
. The identification parts
64
M,
64
C,
64
Y, and
64
B are collectively provided near an open end
64
h
that is an edge of the shutters
64
(
64
m
,
64
c
,
64
y
,
64
b
) facing the developing roller
12
, and near the longitudinal side of the driving force receiver section.
As shown in
FIG. 25
, four seats
64
s
capable of longitudinally and equally attaching thereto pieces
64
r
in a straight line are equally spaced on the shutters
64
(
64
m
,
64
c
,
64
y
,
64
b
) in order to mount thereon the identification parts
64
M,
64
C,
64
Y, and
64
B. Each of the seats
64
s
has positioning holes
64
p
and
64
q
arranged side by side in a circumferential direction of the shutters
64
(
64
m
,
64
c
,
64
y
,
64
b
). The hole
64
p
is a round hole, and the hole
64
q
is a slot elongated in the circumferential direction of the shutters
64
(
64
m
,
64
c
,
64
y
,
64
b
). Each of the pieces
64
r
has a cubic shape, and projections are formed on its plane (not shown in
FIG. 25
) opposing each of the seats
64
s
so as to be fitted into the holes
64
p
and
64
q
. The projections are fitted into the holes
64
p
and
64
q
to position each of the pieces
64
r
, and the seat
64
s
and piece
64
are fixed by bonding.
One piece
64
r
is mounted on any one of the four seats
64
s
to form one of the identification parts
64
M,
64
C,
64
Y, and
64
B. When attaching the developing cartridges D (Dm, Dc, Dy, and Db) having the identification parts
64
M,
64
C,
64
Y, and
64
B to the cartridge attachment sections
14
m
,
14
c
,
14
y
, and
14
b
, respectively, the identification parts
64
M,
64
C,
64
Y, and
64
B can fit into the identification parts
11
m
1
,
11
c
1
,
11
y
1
, and
11
b
1
of the cartridge attachment sections
14
m
,
14
c
,
14
y
, and
14
b
to enter into the cartridge attachment sections
14
m
,
14
c
,
14
y
, and
14
b
, respectively, as shown by one example in FIG.
26
. However, all of the identification parts
64
M,
64
C, and
64
B of the developing cartridges Dm, Dc, and Db abut against the edge of the partition
11
y
of the cartridge attachment section
14
y
without the identification part
11
y
1
, so that the developing cartridges Dm, Dc, and Db cannot be attached to the cartridge attachment section
14
y
for the developing cartridge Dy.
Similarly, the developing cartridges Dy, Dc, and Db cannot be attached to the cartridge attachment section
14
m
for the developing cartridge Dm; the developing cartridges Dy, Dm, and Db cannot be attached to the cartridge section
14
c
for the developing cartridge Dc; and the developing cartridges Dy, Dm, and Dc cannot be attached to the cartridge attachment section
14
b
for the developing cartridge Db.
FIGS. 2 and 26
show a state where the developing cartridge Dc is being attached to the cartridge attachment section
14
c
. In the attachment of the developing cartridge Dc to the cartridge attachment section
14
c
, the guide section
70
of the developing cartridge Dc is inserted into the guide section-insertion section
59
h
of the cartridge attachment section
14
c
, the shutter
64
linearly enters into the cartridge attachment section
14
c
and at the same time, the developing cartridge Dc moves laterally to reach a position where the positioning bosses
63
m
(
63
m
1
and
63
m
2
) of the developing cartridge Dc can enter into the guide section
11
j
provided on the inner wall surface
11
a
of the drive side flange
11
g
of the rotary unit
11
. In addition, the identification part
64
C reaches an edge
11
x
of the partition
11
c
. However, since the edge
11
x
has the recessed identification part
11
c
1
into which only the identification part
63
C can enter, the projection
63
c
is fitted into the fitting section
59
f
, the identification parts
11
c
1
and
64
C fit to each other, and the bosses
63
m
(
63
m
1
and
63
m
2
) enter into the guide section
11
j
, so that the developing cartridge Dc is located at the position shown in
FIGS. 2
,
17
, and
26
. If the cartridge frame
63
is rotated clockwise, the developing cartridge Dc is attached to the cartridge attachment section
14
c
in such a manner as mentioned above, as shown in FIG.
3
.
If the developing cartridges Dm, Dy, Db are to be attached to the cartridge attachment section
14
c
for the developing cartridge Dc, the guide sections
70
of the developing cartridges Dm, Dy, and Db can be inserted into the guide section-insertion section
59
h
. However, the identification parts
64
M,
64
Y, and
64
B abut against the outer peripheral edge
11
x
of the partition
11
c
when the leading ends of the guide sections
70
reach the position
13
shown in
FIG. 2
, so that the developing cartridges Dm, Dy, and Db cannot further advance linearly. In addition, as shown in
FIG. 16
, since the cut sections
63
c
1
of the projection
63
c
have already entered between the linear ribs
59
c
(see FIG.
14
), the developing cartridges Dm, Dy, and Db cannot be rotated. Accordingly, the developing cartridges Dm, Dy, and Db other than the developing cartridge Dc cannot be attached to the cartridge attachment section
14
c.
Similarly, the developing cartridges Dm, Dy, and Db can be attached only to the corresponding cartridge attachment sections
14
m
,
14
y
, and
14
b
, respectively, but any other development cartridge cannot be attached.
As described above, in this embodiment, there are provided the shutters
64
(
64
m
,
64
c
,
64
y
, and
64
b
) mounted on the developing cartridges D (Dm, Dc, Dy, and Db), which can be attached to and detached from the image forming apparatus main body
30
forming a multicolored image, and which develop a latent image formed on the photoconductive drum
1
. The shutters
64
(
64
m
,
64
c
,
64
y
, and
64
b
) are rotatably mounted on the developing cartridges D (Dm, Dc, Dy, and Db) at the longitudinal center of the cartridge frames
63
of the developing cartridges D (Dm, Dc, Dy, and Db). The shutters
64
(
64
m
,
64
c
,
64
y
, and
64
b
) can move between a cover position to cover the portions of the developing rollers
12
exposed from the cartridge frames
63
when the cartridges D (Dm, Dc, Dy, and Db) are located outside the apparatus main body
30
and a retracted position to retract from the cover position so as to expose the developing rollers
12
from the cartridge frames
63
when the cartridges D (Dm, Dc, Dy, and Db) are attached to the cartridge attachment positions of the apparatus main body
30
. The shutters
64
(
64
m
,
64
c
,
64
y
, and
64
b
) include the identification parts
64
M,
64
C,
64
Y, and
64
B that coincide with and enter into the identification parts
11
m
1
,
11
c
1
,
11
y
1
, and
11
b
1
formed in the apparatus main body
30
when one of the developing cartridges D (Dm, Dc, Dy, and Db) is attached to one of the developing cartridge attachment sections
14
(
14
m
,
14
c
,
14
y
, and
14
b
) provided in the apparatus main body
30
. The provision of such shutters
64
(
64
m
,
64
c
,
64
y
, and
64
b
) on the developing cartridges D (Dm, Dc, Dy, and Db) can prevent the user from attaching an inappropriate developing cartridge to a cartridge attachment section of the apparatus main body.
Since common seats
64
s
are provided on each of the shutters
64
(
64
m
,
64
c
,
64
y
, and
64
b
) in advance and the piece
64
r
is selectively attached thereto to form each of the identification parts
64
M,
64
C,
64
Y, and
64
Y, it is not particularly necessary to prepare a variety of shutters
64
, thereby reducing an increase in the cost of the device.
The identification parts
64
M,
64
C,
64
Y, and
64
B, and
11
m
1
,
11
c
1
,
11
y
1
, and
11
b
1
may be provided at places other than those on the side of the driving force receiver section, as long as the identification parts are in the longitudinal direction. In addition, these identification parts may be unequally spaced. The identification parts may be formed in any shape, as long as it is the shape of a square projection or recess.
(Configuration of Developing Frame)
As shown in
FIGS. 4
,
6
, and
7
, the cartridge frame
63
is composed of the developing member-supporting frame (main cartridge frame)
63
A, a toner frame
63
B, a cover frame
63
C, side covers (developer cartridge side covers)
63
D and
63
E, and a coupling frame
63
F.
As shown in
FIG. 4
, triangular ribs are longitudinally provided on combined surfaces
63
n
between flanges
63
Aa provided laterally on both sides of the developing member-supporting frame
63
A and flange
63
Ba provided on the toner frame
63
B, and the triangular ribs are ultrasonically welded to combine both frames
63
A and
63
B.
The flange
63
Ba is formed to have a hooked shape in cross section so that openings
630
of the toner frame
63
B and the cover frame
63
C are combined to form one toner case, and a flange
63
Bb having a combined surface
63
p
between the upper surface of the flange
63
Bb and the cover frame
63
C as one plane is provided to surround the openings
63
o
. A flange
63
Cb surrounding the opening
63
o
of the cover frame
63
C is brought into contact with the flange
63
Bb on the combined surface
63
p
so as to be ultrasonically welded.
In addition, as shown in
FIGS. 6 and 7
, the side covers
63
D and
63
E cover the longitudinal both sides of the combined developing member-supporting frame
63
A and the toner frame
63
B, the side cover
63
E is secured to the developing member-supporting frame
63
A by screws, and the side cover
63
D is secured by screws to the coupling frame
63
F fixed to the developing member-supporting frame
63
A, whereby all the frames form the integral cartridge frame
63
.
(Developing Member-supporting Frame)
As shown in
FIGS. 4
,
5
,
27
and
28
, the developing member-supporting frame
63
A project along substantially the entire length thereof from the flanges
63
Aa toward a toner supply opening section
63
Bc that is opened toward the developing member-supporting frame
63
A. A projection front surface
63
Ab has a longitudinal plane
63
Ab
1
whose longitudinal one end closely opposes a toner seal surface
27
a
to which the toner seal
27
is longitudinally applied with the toner seal
27
placed therebetween, and lateral planes
63
Ab
2
that extend laterally at both longitudinal ends of the front surface
63
Ab opposite to an edge of the toner supply opening section
63
Bc. The longitudinal plane
63
Ab
1
is flush with the lateral planes
63
Ab
2
. Each of the lateral planes
63
Ab
2
consecutively forms a circular surface
63
Ab
3
that is coaxial with the application roller
19
and has a radius slightly larger than that of the application roller
19
immediately to the longitudinal outside of the application roller
19
. Each of the lateral planes
63
Ab
2
and circular surface
63
Ab
3
has a narrow width. The longitudinal plane
63
Ab
1
projects perpendicularly from the flange
63
Aa.
End seals
31
a
and
31
b
made of elastic members are adhered to the developing member-supporting frame
63
A at both longitudinal ends of the projection front surface
63
Ab. In addition, on the drawing side of the toner seal
27
, a film
31
c
for reducing the friction between the toner seal
27
and the developing member-supporting frame
63
A is adhered to the inner side on the end seal
31
a
(see FIG.
27
). As shown in
FIG. 28
, an end seal-adhering surface
63
Ac on which the end seal
31
a
(
31
b
) is adhered is located in a position slightly retracted from the lateral plane
63
Ab
2
at its intermediate section, and has a shape such that both lateral ends thereof are rolled by the circular surfaces
63
Ad, and is smoothly curved between the circular surfaces
63
Ad and the flanges
63
Aa to combine them by a circular surface. The end seal
31
a
(
31
b
) is provided between the combined surfaces
63
n
where the flanges
63
Aa are welded. On the other hand, the toner frame
63
B has a seal surface
63
Bu provided opposite to the end seal-adhering surface
63
Ac for pressure-welding the end seal
31
a
(
31
b
) when the developing member-supporting frame
63
A and the toner frame
63
B are combined opposite to the end seal
31
a
(
31
b
).
An opening is formed by being surrounded by the projection front surface
63
Ab, a shaft mounting section
63
q
for the application roller
19
, and the longitudinal flange
63
Aa. The opening passes through the developing member-supporting frame
63
A, and is vertically narrowed between the cleaning blade
16
and a sheet-like seal member
34
to form a toner supply opening
63
Ae facing the developing roller
12
. The developing roller
12
is attached to a developing roller attachment section along the front face of the toner supply opening
63
Ae (see FIG.
29
).
As described above, the developing member-supporting frame
63
A is a developing frame including the developing roller
12
for developing a latent image formed on the photoconductive drum
1
, the toner storage section
63
a
for storing toner used by the developing roller
12
for development, and the application roller
19
for applying the toner around the developing roller
12
, and is used for the developing cartridge D that can be attached to and detached from the apparatus main body
30
. The developing member-supporting frame
63
A includes the toner supply opening
63
Ae for supplying the toner stored in the toner storage section
63
a
to the developing roller
12
, the developing roller attachment section for attaching thereto the developing roller
12
along the toner supply opening
63
Ae, the combined surfaces
63
n
provided longitudinally on both lateral ends of the toner supply opening
63
Ae for combining the developing member-supporting frame
63
A and the toner frame
63
B having the toner storage section
63
a
, and a projected section formed by the projection front surface
63
Ab, the shaft mounting section
63
q
, the adhering surfaces
63
Ac for the end seals
31
a
and
31
b
that project in such a manner as to cut across a plane connecting the combined surfaces
63
n.
A configuration of the developing member-supporting frame
63
A on the opposite side of the toner frame
63
B across the plane connecting the combined planes
63
n
will now be described.
As shown in
FIG. 4
, the shaft mounting section
63
q
for supporting a metallic rotation shaft
19
a
of the application roller
19
is integrally formed with the developing member-supporting frame
63
A, and shaft receiver holes provided near longitudinal both ends of the developing member-supporting frame
63
A into which the rotation shaft
19
a
is fitted are located closer to the developing roller
12
than the plane connecting the combined surfaces
63
n
. That is, the shaft receiver holes are located on the opposite side of the toner frame
63
B with the plane connecting the combined surface
63
n
placed therebetween.
The shaft mounting section
63
q
includes a circularly recessed surface
63
Ag in order to adhere a felt elastic seal member
32
of substantially uniform thickness for sealing between the development area and the outside on a portion without the spacer rollers
12
a
and
12
b
apart from both ends of the developing roller
12
. The circularly recessed surface has continuously connected planes
63
Ag
1
that are substantially in parallel with the developing blade
16
, and longitudinal both ends of an elastic blade
16
c
approaching the generating line of the developing roller
12
overlap the portion of the elastic seal member
32
adhered on the planes
63
Ag
1
. In addition, the elastic sheet-like seal member
34
, approaching the generating line of the developing roller
12
in parallel with the elastic blade
16
c
, is adhered on a seal mounting surface
63
r
having a stepped portion so as to be located higher than the circularly recessed surface
63
Ag and to be brought closer to the surface of the developing roller
12
(see FIG.
28
).
As shown in
FIG. 29
, a recess
63
s
of circular cross section about the rotation shaft
19
a
of the application roller
19
is provided longitudinally on the outside of the shaft mounting section
63
q
, and a shaft seal packing
35
is provided so as to be fitted into the recess
63
c
and the rotation shaft
19
a
. The packing
35
is lightly pressed into contact with an axial outer surface of the shaft mounting section
63
q
by cylindrical projections
63
Df and
63
Ef (see
FIG. 35
, but projection
63
Df is not shown therein) provided on the side cover
63
D and the coupling frame
63
F, respectively, which enter into the recess
63
s
, thereby performing shaft sealing operation. The above-mentioned arrangements are similar on both longitudinal ends.
The foregoing is the configuration of the developing member-supporting frame
63
A for the developing cartridges Dm, Dc, and Dy. However, since the developing cartridge Db does not have the application roller
19
, the developing member-supporting frame
63
A thereof does not include the shaft mounting section
63
q
for mounting the rotation shaft
19
a
of the application roller
19
, and the shape of a space, etc., to seal the rotation shaft. As shown in
FIG. 5
, a bottom
63
t
of the developing member-supporting frame
63
A is formed to substantially a horizontal surface passing downward of the developing roller
12
at the development position provided opposite to the photoconductive drum
1
.
As shown in
FIG. 27
, bearing surfaces
63
Ak
1
and
63
Ak
2
are provided on both longitudinal ends of the developing member-supporting frame
63
A so as to mount thereon the coupling frame
63
F and the side cover
63
E, respectively. These bearing surfaces
63
Ak
1
and
63
Ak
2
are of identical shape with each other. Each of the bearing surfaces
63
Ak
1
and
63
Ak
2
has a female screw hole
63
Am, and positioning holes
63
An and
63
Ap. The positioning hole
63
An is a round hole, and the positioning hole
63
Ap is a slot of elongated section along a line connecting both holes
63
An and
63
Ap.
The developing member-supporting frame
63
configured as described above can allow the reduction in size of the developing cartridge as compared with a conventional configuration thereof. Alternatively, the developing cartridges of the same size can store larger amount of toner.
(Toner Frame)
As shown in
FIG. 4
, the combined surfaces
63
n
between the toner frame
63
B and the developing member-supporting frame
63
A, and the combined surface
63
p
between the toner frame
63
B and the cover frame
63
C are located on the planes substantially perpendicular to each other, respectively.
As shown in
FIGS. 30 and 31
, the journal
33
integrally molded with the agitation gear
23
d
is rotatably supported by a hollow cylindrical bearing section
63
Be provided on an end plate
63
Bd of one longitudinal end of the toner frame
63
B, and a journal
36
is rotatably supported by a bearing section
63
Bq located in the center of a cylindrical toner replenish port
63
Bp provided on the other end longitudinal end of the toner frame
63
B. The bearing section
63
Bq is integrally molded with the toner frame
63
B connected between the bearing section
63
Be and the toner replenish port
63
Bp by means of radial arms
63
bs
. The toner feeding member (referred to also as toner agitation member)
15
is supported by the journals
33
and
36
. The toner feeding member
15
extends substantially the entire length of the toner frame
63
B, and both ends thereof are located outside the development area. A first and second openings
63
Bf and
63
Bg are provided outside the development area on the side of a toner cap
37
fitted and fixed into the toner replenish port
63
Bp, as shown in FIG.
4
. Translucent members
81
and
82
made of, for example, synthetic resin, are fitted and fixed into the first and second openings
63
Bf and
63
Bg, respectively. An incident light from the first opening
63
Bf can pass through the second opening
63
Bg when a small amount of toner is stored within the toner frame
63
B. As shown in
FIGS. 4
,
5
, and
32
, an opening
64
k
through which the emergent light from the second opening
63
Bg passes is formed in the shutter
64
.
The translucent members
81
and
82
have a cylindrical surface
81
a
and a flat surface
82
a
, respectively, on which an elastic blade
15
a
provided on a blade supporting sheet metal
15
b
of the toner feeding member
15
deflects and slides, provided within the toner frame
63
B in such a manner as to cut into a movement path of the elastic blade
15
a
. The cylindrical surface
81
a
is a surface about the center of rotation of the toner feeding member
15
, and the flat surface
82
a
is a plane that is at right angles to the perpendicular dropped from the center of the cylindrical surface
81
a
on the center of the flat surface
82
a.
(Cover Frame)
As mentioned above, the flanges
63
Aa and
63
Ba for combining the developing member-supporting frame
63
A and the toner frame
63
B are shaped so as to be offset toward the developing roller
12
rather than the toner seal surface
27
a
, a front wall
63
Cd of the cover frame
63
C can be moved to the developing member-supporting frame
63
A, thereby extending a distance between the rear wall
63
Ce and the front wall
63
Cd. Accordingly, a content volume obtained by combining the toner frame
63
B and the cover frame can be increased.
(Coupling Frame)
As shown in
FIG. 34
, the coupling frame
63
F is fixed to the bearing surface
63
Ak
1
on the driving force receive side of the developing member-supporting frame
63
A by screwing a small screw (not shown) into the female screw hole Am through a small screw hole
63
Fa. This allows the bearing surface
63
Ak
1
to abut against a mounting surface
63
Fk of the coupling frame
63
F. The shape of the mounting surface
63
Fk is substantially the same as the bearing surface
63
Ak
1
, and both surfaces coincide with each other. Longitudinal cylindrical dowels (not shown) fitted into the positioning holes
63
An and
63
Ap of the bearing surface
63
Ak
1
, respectively, are provided on the mounting surface
63
Fk.
As shown in
FIG. 34
, one end of the rotation shaft
12
c
of the developing roller
12
is supported by a developing roller bearing
38
fitted into the coupling frame
63
F. A projection shaft
63
Fb for supporting the driving force receiver member
22
is integrally formed with the coupling frame
63
F. A projection shaft
63
Fc is integrally formed with the coupling frame
63
F. The idler gear
23
c
having the small gear
23
c
2
meshing with the gear
23
d
is rotatably supported by the projection shaft
63
Fc (see FIGS.
22
and
34
). In addition, a hole
63
Fd is formed in the coupling frame
63
F for inserting therethrough the rotation shaft
19
a
of the application roller
19
. Further, a female screw hole
63
Fe for mounting the side cover
63
D is provided in the coupling frame
63
F.
Support of the developing roller on the side opposite to the drive side, and a drawing port of the toner seal
27
will now be described.
(Side Cover on Non-Drive Side)
As shown in
FIG. 35
, the side cover
63
E on the non-drive side has a shape to cover the longitudinal end surfaces of the developing member-supporting frame
63
A and the toner frame
63
B. A mounting surface
63
Ea is provided so as to contact the bearing surface
63
Ak
2
, and the mounting surface
63
Ea has provided thereon longitudinally cylindrical dowels
63
Eb, which are fitted into the positioning holes
63
An and
63
Ap, respectively. In addition, a small screw hole
63
Ec passes longitudinally through the side cover
63
E at a position corresponding to the female screw hole
63
Am into which a small screw is inserted to be screwed into the female screw hole
63
Am from the outside so as to fix the side cover
63
E to the developing member-supporting frame
63
A. In a state where the side cover
63
E is mounted on the developing member-supporting frame
63
A, a developing roller bearing
39
for rotatably supporting the rotation shaft
12
c
of the developing roller
12
is longitudinally fitted into a hole of the side cover
63
E.
A cylindrical projection
63
Ef projects longitudinally from the mounting surface
63
Ea so that the head of the projection
63
Ef presses the shaft seal packing
35
of the rotation shaft
19
a
of the application roller
19
to the shaft mounting section
63
q
of the rotation shaft
19
a
. In addition, a cover
63
Eg is integrally formed for covering the outer periphery of the projection end of the rotation shaft
12
c
of the developing roller
12
. The cover
64
Eg has an inner surface
63
Eh that is the same as the seal surface of the elastic seal member
32
shown in
FIG. 29
, and is longitudinally connected to the seal surface so as to be flush therewith in a mounted state of the side cover
63
E.
A toner seal opening
63
Ei passes longitudinally through the side cover
63
E through which an end of the toner seal
27
is inserted so as to draw the toner seal
27
out of the developing cartridge D. The toner seal opening
63
Ei is of a rectangular shape elongated along the width of the toner seal
27
, and a vertical side thereof shown in
FIG. 35
is longer than the width of the toner seal grip
73
(see FIG.
9
).
FIG. 31
is a horizontal sectional view of the toner frame
63
B including a toner supply opening section
63
Bc. The toner seal
27
is applied to the entire peripheral edge of the toner supply opening section
63
Bc, is turned at a turn section
27
b
, is overlapped with the applied toner seal, and is bonded to the toner seal grip
73
at an end
27
c
. The end
27
c
of the toner seal
27
and the toner seal grip
73
are located within the toner seal opening
63
Ei, and extend from the developing cartridge D.
As shown in
FIG. 31
, the toner seal opening
63
Ei has a plane including the portion of the toner seal
27
applied to the edge of the toner seal opening section
63
Bc, and a toner seal-leading inclined surface
63
Ej intersected by the line perpendicular to the plane of
FIG. 3
with respect to the drawing direction of the toner seal
27
. The inclined surface
63
Ej is a plane, and allows the toner seal
27
to be inclined toward the toner frame
63
B rather than the toner seal surface
27
a
with respect to the drawing direction of the toner seal
27
. In addition, the toner seal opening
63
Ei has a plane
63
Ek following the inclined surface
63
Ej that is longitudinally in parallel with the applied surface of the toner seal
27
. The inner wall of the toner seal opening
63
Ei is formed into a square shape by one surface including the inclined surface
63
Ej and the plane
63
Ek, and other three planes. The inclined surface
63
Ej may be a quadric surface whose generating line cuts across the toner seal
27
.
When the toner seal grip
73
is pulled outward, the toner seal
27
is drawn out via the toner seal opening
63
Ei from an end fixed by the toner seal grip
73
, the turn section
27
b
moves leftward in
FIG. 31
, and the toner seal
27
is stripped from the edge of the toner supply opening section
63
Bc. By drawing out the entire toner seal
27
, the toner supply opening section
63
Bc is fully open. This enables the toner in the toner frame
63
B to be supplied to a development chamber
63
At of the developing member-supporting frame
63
A. When the toner seal
27
is drawn out, the toner seal
27
is stretched between a corner
63
Bm sealed by the end seal
31
a
of the toner frame
63
B and a corner
63
Em formed by the inclined surface
63
Ej and the mounting surface
63
Ek, so that the toner seal
27
turned at the front face of the toner seal opening section
63
Bc is pulled along the toner seal surface on the edge of the toner supply opening section
63
Bc, and then is sequentially stripped from the turn section
27
b
. The toner seal is stripped in a fixed direction from the turn section
27
b
until it passes through the end seal
31
a
. The toner seal opening
63
Ei of the side cover
63
E allows the user to control the direction to pull the toner seal
27
, thereby preventing tear of the end seal
31
a
and toner leakage when the toner seal
27
is pulled in improper directions.
By integrally forming a shaft supporting member for fitting therein the bearing
39
of the developing roller
12
with the side cover
63
, the number of components can be reduced.
(Configuration of Developing Blade of Developing Cartridge)
Configurations of the developing blades (control members) of the yellow, cyan, and magenta developing cartridges except the black developing cartridge will now be described with reference to FIG.
36
.
The developing blade
16
consists of the blade-supporting sheet metal
16
a
and the elastic blade
16
c
, as briefly described above. For a detailed description hereinbelow, the blade-supporting sheet metal
16
a
consists of a support plate
101
and a presser plate
103
, and the reference numeral
16
c
of the elastic blade is replaced with
102
.
The developing blade
16
has a three-layer construction of the support plate (abutting member)
101
, the elastic blade (elastic member)
102
, and a presser plate (overlap member)
103
in that order near the developing member-supporting frame
63
A, as shown in FIG.
36
.
Positioning bearing surfaces
63
A
1
and
63
A
2
are provided on both longitudinal ends of the developing member-supporting frame
63
A for mounting thereon the developing blade
16
. Female screw holes
63
A
3
are formed in the bearing surfaces
63
A
1
and
63
A
2
, respectively, for fixing the developing blade
16
to the developing member-supporting frame
63
A. A square dowel
63
A
4
stands upright on the bearing surface
63
A
1
at the longitudinal outside of the female screw
63
A
3
. A round dowel
63
A
6
stands upright on the bearing surface
63
A
2
at the longitudinal outside of the female screw hole
63
A
3
.
Holes
101
c
,
102
c
, and
103
c
for loosely fitting therein and inserting therethrough a small screw
105
are formed in one ends of the support plate
101
, the elastic blade
102
, and the presser plate
103
, respectively, so as to coincide with the female screw hole
63
A
3
of the bearing surface
63
A
2
, and holes
101
d
,
102
d
, and
103
d
for a small screw
106
are formed in the other ends, respectively, so as to coincide with the female screw hole
63
A
3
of the bearing surface
63
A
1
.
In both ends of the support plate
101
, the elastic blade
102
, and the presser plate
103
at the same positions of the longitudinal outside of the holes
101
c
,
102
c
,
103
c
, and
101
d
,
102
d
,
103
d
, round holes
102
e
and
102
f
into which the round dowels
101
e
and
101
f
are fitted, respectively, are formed in the support plate
101
and the elastic blade
102
, and round holes
103
e
and
103
f
into which the round dowels
101
e
and
101
f
are fitted, respectively, are formed in the presser plate
103
.
Holes
101
g
and
103
g
into which the round dowels
63
A
6
provided on the bearing surface
63
A
2
are fitted are formed in the other end of the support plate
101
and the presser plate
103
, respectively. The hole
101
g
of the support plate
101
is a slot that is perpendicular to the longitudinal direction and is elongated in the lateral direction, and the hole
103
g
is a round hole into which the round dowel
63
A
6
is just fitted. In addition, square notches
101
h
and
103
h
into which the square dowel
63
A
4
provided on the bearing surface
63
A
1
is fitted are provided in one end of each of the support plate
101
and the presser plate
103
, respectively. The lateral width of the notch
101
h
of the support plate
101
is wider than that of the square dowel
63
A
4
, and the notch
103
h
of the presser plate
103
has the width into which the square dowel
63
A
4
is just fitted.
The developing blade
16
is mounted to the developing member-supporting frame
63
A in the following manner.
(1) The support plate
101
is placed on the bearing surfaces
63
A
1
and
63
A
2
of the developing member-supporting frame
63
A.
(2) The elastic blade
102
is placed on the support plate
101
with reference to the round dowels
101
e
and
101
f
of the support plate
101
(the round holes
102
c
and
102
d
of the elastic blade
102
correspond to the round dowels
101
e
and
101
f
of the support plate
101
).
(3) The presser plate
103
is placed on the elastic blade
102
with reference to the round dowel
63
A
6
and the square dowel
63
A
4
of the developing member-supporting frame
63
A.
(4) The support plate
101
, the elastic blade
102
, and the presser plate
103
are fastened by the small screws
105
and
106
.
Then, the round dowel
63
A
6
is fitted into the hole
101
g
of the support plate
101
and the hole
103
g
of the presser plate
103
so as to bring the both ends of the support plate
101
into abutment with the bearing surfaces
63
A
1
and
63
A
2
, respectively. The lateral position of one end of the developing blade
16
and the longitudinal position of the developing blade
16
are determined by the round dowel
63
A
6
being fitted into the hole
103
g
of the presser plate
103
. The lateral position of the other end of the developing blade
16
is determined by the square dowel
63
A
4
being fitted into the notch
103
h
of the presser plate
103
.
The position of the developing blade can be adjusted. The adjustment is made by moving the support plate
101
laterally (and the developing blade
102
positioned by the round dowels
101
e
and
101
f
) with the small screws
105
and
106
loose.
The support plate
101
and the presser plate
103
are made from sheet metal materials each having a thickness of about 1 to 2 mm. Since rust or the like formed on these sheet metal materials causes a malfunction of development, stainless steel materials are employed for these sheet metal materials or these sheet metals are plated with nickel, etc. The elastic blade (elastic member)
102
includes a metallic plate member, and a resin member provided on an end of the plate member. More specifically, resin as a developing roller-abutting section
102
b
having a thickness of about 1 mm and a width of about 5 mm is integrally molded with an end of a springy thin sheet metal
102
a
(such as phosphor bronze) having a thickness of about 0.2 mm by an outsert molding, etc. The developing roller-abutting section
102
b
is urged by a resilient force generated from the springy thin sheet metal
102
a
toward the developing roller
12
so as to abut against the developing roller
12
with a certain abutting force. Since the amount of charging of the toner is changed by the abutting force, the abutting force is always kept constant by a method described below.
(Means for Equalizing Abutting Pressure of Developing Blade)
As shown in
FIGS. 36 and 37
, the support plate
101
is arranged on the bearing surfaces
63
A
1
and
63
A
2
of the developing member-supporting frame
63
A so as to form a bearing surface for supporting the elastic blade
102
.
The elastic blade
102
is arranged on the support plate
101
, and the presser plate
103
is arranged thereon. The presser plate
103
and the developing member-supporting frame
63
A are fastened by the small screws
105
and
106
, whereby the support plate
11
, the elastic blade
102
, and the presser plate
103
are fixed to the developing member-supporting frame
63
A.
The press-contacting force of the elastic blade
102
and the developing roller
12
is defined by a distance between a point at which the elastic blade
102
is supported, i.e., a support plate end surface
101
a
, and a point N at which the elastic blade
102
abuts against the developing roller
12
, and a deflection angle θ of the elastic blade
102
.
As shown in
FIG. 38
, however, if the support plate
101
warps longitudinally in the direction Z
1
or if the presser plate
103
warps longitudinally in the direction Z
2
, the support plate
101
, the elastic blade
102
, and the presser plate
103
are adhered closely to one another at both ends
107
of the developing member-supporting frame
63
A near the fastened points, whereas a clearance L is generated between the support plate
101
and the presser plate
103
at a center portion
108
of the developing member-supporting frame
63
A far from the fastened points.
Therefore, as shown in
FIG. 39
, the elastic blade
102
is inclined at an angle a to the support plate
101
at the center portion
108
, and hence the deflection angle θ of the elastic blade
102
decreases to θ1, resulting in a decreased abutting pressure of the developing blade
16
.
In this embodiment, as shown in
FIG. 40
, the end surface
101
a
of the support plate is of a circular shape such that the longitudinal center portion thereof projects more than the both ends thereof. In addition, a rear edge
101
b
is in parallel with the developing roller
12
. This shape allows the width in the center portion of overlapped portions of the support plate
101
and the elastic blade
102
to be wider than that in both ends thereof. The distance between the end surface
101
a
and the point N becomes gradually short toward the longitudinal center of the developing member-supporting frame
63
A. In addition, the inclination angle a of the elastic blade
102
to the support plate
101
is reduced.
Consequently, even if the support plate
101
or the presser plate
103
warps as described above to generate the clearance L between the support plate
101
and the presser plate
103
, it is possible to prevent a reduction in the press-contacting force of the developing blade
16
by correcting the position of the end surface
101
a
and the deflection angle θ of the elastic blade
102
in the longitudinal direction.
Second Embodiment
The configuration of the developing blade
16
is the same as that of the first embodiment.
In the case where the bearing surfaces
63
A
1
and
63
A
2
of the developing member-supporting frame
63
A are inclined inward in the directions Z
4
and Z
5
, as shown in
FIG. 41
, the support plate
101
warps in the direction Z
1
shown in
FIG. 38
under the influence of the bearing surfaces
63
A
1
and
63
A
2
. Therefore, the clearance L is generated at the center portion
108
, and the deflection angle θ of the elastic blade
12
decreases to θ1, as shown in
FIG. 39
, resulting in a decreased press-contacting force of the developing blade
16
.
In this embodiment, the support plate
101
is warped in the direction Z in advance toward the center portion
108
, as shown in FIG.
41
. This allows the inclination of the bearing surfaces
63
A
1
and
63
A
2
in the directions Z
4
and Z
5
, respectively, to be absorbed by the warp of the support plate
101
in the direction Z
2
, and can prevent the generation of the clearance L also at the center portion of the developing member-supporting frame
63
A. Therefore, the deflection angle θ shown in
FIG. 39
does not decrease, and a stable abutting pressure of the developing blade
16
can be always provided.
Third Embodiment
The present invention is applicable to a process cartridge. The process cartridge is a cartridge including a charging means or a cleaning means, a developing means, and an electrophotographic photosensitive member integrally formed in a cartridge, and the cartridge can be attached to and detached from an image forming apparatus main body. In addition, the process cartridge is a cartridge including at least one of the charging means and the cleaning means, the developing means, and the electrophotographic photosensitive member integrally formed in a cartridge so as to be attached to and detached from the image forming apparatus main body. Further, the process cartridge is a cartridge including the developing means and the electrophotographic photosensitive member integrally formed in a cartridge so as to be attached to and detached from the apparatus main body.
FIG. 42
shows an image forming apparatus (laser beam printer) A having attached thereto a process cartridge B.
The process cartridge B includes a charging unit
2
, a developing unit DA including a developing roller
12
, and a cleaning unit
9
provided around a photoconductive drum
1
, and is integrally formed in a cartridge by a cartridge frame so as to be detachably attached to an image forming apparatus main body
30
A. A toner image formed by an image forming section formed in the process cartridge is transferred by a transfer means (transfer roller)
6
to a recording medium P conveyed by a pickup roller
5
b
from a paper feeding cassette
5
, is fixed by a fixing means
7
and then is discharged to a discharge section
8
.
When a laser beam modulated in response to a time sequence electric image signal of a target image is output from a semiconductor laser to a polygon mirror
3
a
, an exposure means
3
forms a latent image responsive to the target image on the photoconductive drum
1
, which is uniformly charged by the charging means
2
in advance and is rotating clockwise, via a lens
3
c
and a reflecting mirror
3
d
. The latent image is applied to the toner from the developing unit DA, and moves to an opposite section of the transfer roller
6
.
The developing unit DA has a configuration similar to that of the above-mentioned black developing cartridge Db, and a developing blade
16
is pressed into contact with a generating line of the developing roller
12
. The developing blade described in the first and second embodiments may be employed as the developing blade
16
.
As described above, there is provided a developing device or a developing means, which is a component of a process cartridge, including a developing roller
12
for developing a latent image formed on a photoconductive drum; a developing blade
16
for controlling the thickness of toner coated on the developing roller
12
: and a cartridge frame
63
for supporting the developing roller
12
and the developing blade
16
, wherein the developing blade
16
has a developing blade support plate
101
abutting against the cartridge frame
63
; an elastic blade
102
overlapped the developing blade support plate
101
and elastically coming into contact with the developing roller
12
; a presser plate
103
for clamping the elastic blade
102
between the developing blade support plate
101
and the presser plate
103
; and small screws
105
and
106
for fastening the developing blade to the cartridge frame
63
, and wherein the width in the center portion of overlapped portions of the developing blade support plate
101
and the elastic blade
102
is wider than that in both ends thereof.
In the developing device, a widthwise one end surface of the developing blade support plate
101
near the developing roller
12
is formed by a smooth curve.
In the developing device, a longitudinal center portion of a front edge of the developing blade support plate
101
is formed as a projection so as to be closer to the developing roller
12
than the both ends thereof.
In the developing device, the rear edge of the developing blade support plate
101
, which does not come into contact with the elastic blade
102
and the developing roller
12
, is in parallel with the developing roller
12
.
In the developing device, the width of projection of a portion of the elastic blade
16
, which does not come into contact with the developing blade support plate
101
, is smaller than that in both ends thereof.
In addition, there is provided a developing device including a developing roller
12
for developing a latent image formed on a photoconductive drum; a developing blade
16
for controlling the thickness of toner coated on the developing roller
12
; and a cartridge frame
63
for supporting the developing roller
12
and the developing blade
16
, wherein the developing blade
16
has a developing blade support plate
101
abutting against the cartridge frame
63
; an elastic blade
102
overlapped the developing blade support plate
101
and elastically coming into contact with the developing roller
12
; a presser plate
103
for clamping the elastic blade
102
between the developing blade support plate
101
and the presser plate
103
; and small screws
105
and
106
for fastening the developing blade
16
to the cartridge frame
63
, and wherein the surface of the developing blade support plate
101
on the side of contacting the elastic blade
102
is curved so that the longitudinal center portion thereof comes into contact with the elastic blade
102
earlier than both ends thereof.
As described above, according to the present invention, it is possible to reliably obtain an abutting pressure of the developing blade against the developing roller. As a result, it is possible to prevent toner leakage and formation of faulty image due to a deficiency of the abutting pressure. In addition, since the abutting pressure to the developing roller can be reliably obtained even if the support plate and the presser plate warp in the longitudinal direction, machining tolerances of the support plate and the presser plate can be alleviated, and the cost of components can be reduced.
While the present invention has been described with reference to what are presently considered to be the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
Claims
- 1. A developing device including a developing-member supporting frame comprising:a developer carrier for carrying a developer; and a control member for controlling a thickness of the developer on said developer carrier, said control member comprising: an abutting member abutting against a reference plane of a main body of the developing device, said abutting member being supported at opposing ends of a supporting frame; an elastic member overlapping said abutting member, wherein said elastic member is inclined at an angle relative to said abutting member at a center portion of the supporting frame with an inclination against said abutting member in the center portion, said elastic member being urged toward said developer carrier, a width in a center portion of overlapped sections of said elastic member and said abutting member being wider than a width at both ends of the overlapped sections; and an overlap member overlapping said elastic member.
- 2. A developing device according to claim 1, wherein said abutting member abuts against the reference plane at both ends thereof.
- 3. A developing device according to claim 1, wherein a width of a longitudinal center portion of said abutting member is wider than the width of both ends thereof.
- 4. A developing device according to claim 1, wherein an end surface of said abutting member on a side of said developer carrier along a width thereof is formed as a projection such that a center portion of the abutting member is closer to said developer carrier than both ends thereof.
- 5. A developing device according to claim 2, wherein said abutting member is mounted on a reference plane of a developing frame at both ends thereof.
- 6. A developing device according to claim 1, wherein an amount of a projection of said elastic member in the center portion thereof from said abutting member to said developer carrier is smaller than the projection in both ends thereof.
- 7. A developing device according to claim 1, wherein said elastic member comprises a metallic plate member, and a resin member provided on an end of said plate member.
- 8. A developing device according to claim 1, wherein said abutting member comprises a projection projecting toward said elastic member.
- 9. A developing device according to claim 1, wherein said developing device attaches to and detaches from a main body of an image forming apparatus.
- 10. A process cartridge for use in a developing device including a developing-member supporting frame comprising:an image carrier; a developer carrier for carrying a developer; and a control member for controlling a thickness of the developer on said developer carrier, said control member including: an abutting member abutting against a reference plane of a main body of the developing device, said abutting member being supported at opposing ends of a supporting frame; an elastic member overlapping said abutting member, wherein said elastic member is inclined at an angle relative to said abutting member at a center portion of the supporting frame with an inclination against said abutting member in the center portion, said elastic member being urged toward said developer carrier, a width in the center portion of overlapped sections of said elastic member and said abutting member being wider than a width in both ends thereof; and an overlap member overlapping said elastic member.
- 11. In a developing device having a main body and a developer carrier, a method of forming a control member that controls a thickness of a developer on the developer carrier comprising the steps of:abutting an abutting member against a reference plane of a main body of the developing device, said abutting member being supported at opposing ends of a supporting frame; positioning an elastic member on said first member in an overlapping relationship, wherein said elastic member is inclined at an angle relative to said abutting member at a center portion of the supporting frame with a inclination against said abutting member in the center portion so that said elastic member is urged toward the developer carrier and a center portion of overlapped sections of said elastic member and said abutting member is wider than end portions of the overlapped sections; and setting an overlap member on said elastic member in an overlapping relationship with said elastic member.
- 12. A developing device comprising:a developer carrier for carrying a developer; and a control member for controlling a thickness of the developer on said developer carrier, said control member including: an abutting member abutting against a reference plans of a main body of the developing device, said abutting member being supported at opposing ends of a supporting frame; an elastic member overlapping said abutting member of the supporting frame relative to said abutting member at a center portion of the supporting member with an inclination against said abutting member in a center portion, said elastic member being urged toward said developer carrier, a width in a center portion of overlapped sections of said elastic member and said abutting member being wider than a width at both ends of the overlapped sections; and an overlap member overlapping said elastic member, wherein an abutting pressure between said elastic member and said developer carrier is substantially maintained at a predetermined level regardless of deflection of said abutting member or said overlap member.
- 13. A developing device comprising:a developer carrier for carrying a developer; a regulating member for regulating an amount of the developer on said developer carrier; first supporting member supporting a developer-carrier side of said regulating member; and a second supporting member supporting an opposite side of the developer-carrier side of said regulating member, wherein a supporting width of said second supporting member is wider in a center portion than in an end portion in a longitudinal direction of said regulating member and wherein a supporting width of said first supporting member for said regulating member is wider than supporting width of said second supporting member.
- 14. A developing device according to claim 13, wherein said regulating member is an elastic member.
- 15. A developing device according to claim 13, wherein an end of a free-end side of said second supporting member is convex.
- 16. A developing device according to claim 13, wherein said first and second supporting members sandwich said regulating member.
- 17. A developing device according to claim 16, wherein said regulating member comprises a metal plate, andwherein said first and second supporting members sandwich said metal plate.
- 18. A developing device according to claim 13, wherein said first and second supporting members are fixed outside a supporting portion of said regulating member in the longitudinal direction of said regulating member.
Priority Claims (1)
Number |
Date |
Country |
Kind |
10-103421 |
Mar 1998 |
JP |
|
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Number |
Name |
Date |
Kind |
4334766 |
Sugiyama et al. |
Jun 1982 |
A |
5895150 |
Watabe et al. |
Apr 1999 |
A |
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