PROCESS CARTRIDGE, ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS, AND

175 Pages·2013·2.46 MB·English

(19) TEPZZ Z874Z7B_T
EP 2 087 407 B1
(11)
(12) EUROPEAN PATENT SPECIFICATION
(45) Date of publication and mention (51) Int Cl.:
G03G21/18(2006.01) G03G21/16(2006.01)
of the grant of the patent:
17.07.2013 Bulletin2013/29
(86) International application number:
PCT/JP2007/075364
(21) Application number: 07860559.9
(87) International publication number:
(22) Date of filing: 25.12.2007
WO2008/078836 (03.07.2008Gazette2008/27)
(54) PROCESS CARTRIDGE, ELECTROPHOTOGRAPHIC IMAGE FORMING APPARATUS, AND
ELECTROPHOTOGRAPHIC PHOTOSENSITIVE DRUM UNIT
PROZESSKARTUSCHE, ELEKTROPHOTOGRAPHISCHE BILDERZEUGUNGSVORRICHTUNG
UND PHOTOSENSITIVE ELEKTROPHOTOGRAPHISCHE TROMMELEINHEIT
CARTOUCHE DE TRAITEMENT, APPAREIL DE FORMATION D’IMAGE
ÉLECTROPHOTOGRAPHIQUE, ET UNITÉ DE TAMBOUR PHOTOSENSIBLE
ÉLECTROPHOTOGRAPHIQUE
(84) Designated Contracting States: (72) Inventors:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR • UENO, Takahito
HU IE IS IT LI LT LU LV MC MT NL PL PT RO SE Tokyo 146-8501 (JP)
SI SK TR • MIYABE, Shigeo
Tokyo 146-8501 (JP)
(30) Priority: 22.12.2006 JP 2006346190 • MORIOKA, Masanari
22.02.2007 JP 2007042665 Tokyo 146-8501 (JP)
21.12.2007 JP 2007330303 • HISANO, Masato
Tokyo 146-8501 (JP)
(43) Date of publication of application:
12.08.2009 Bulletin2009/33 (74) Representative: TBK
Bavariaring 4-6
(60) Divisional application: 80336 München (DE)
13169112.3
13169114.9 (56) References cited:
EP-A- 1 178 370 JP-A- 1 164 818
(73) Proprietor: Canon Kabushiki Kaisha JP-A- 5 341 589 JP-A- 2002 031 153
Tokyo 146-8501 (JP) JP-A- 2004 045 603 US-A1- 2005 191 092
US-A1- 2006 240 896 US-B1- 6 473 580
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0 Note: Within nine months of the publication of the mention of the grant of the European patent in the European Patent
Bulletin, any person may give notice to the European Patent Office of opposition to that patent, in accordance with the
2
Implementing Regulations. Notice of opposition shall not be deemed to have been filed until the opposition fee has been
P
paid. (Art. 99(1) European Patent Convention).
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Printed by Jouve, 75001 PARIS (FR)
1 EP2 087 407B1 2
Description provided with a plurality of corners, is provided.
[0008] When the rotatable member is rotated in an en-
[TECHNICAL FIELD] gaged state between the projection and the hole in the
case where the process cartridge is mounted to the ap-
[0001] The present invention relates to a process car- 5 paratus main assembly, a rotational force of the rotatable
tridge, an electrophotographic image forming apparatus member is transmitted to the photosensitive drum in a
to which the process cartridge is detachably mountable, state in which an attraction force toward the hole is ex-
and an electrophotographic photosensitive drum unit. erted on the projection. As a result, the rotational force
[0002] Examples of the electrophotographic image for rotating the photosensitive drum is transmitted from
forming apparatus include an electrophotographic copy- 10 the apparatus main assembly to the photosensitive drum
ing machine, an electrophotographic printer (a laser (U.S. Patent No. 5,903,803).
beam printer, an LED printer, and so on), and the like. [0009] Further, a method in which a photosensitive
[0003] The process cartridge is prepared by integrally drum is rotated by engaging a gear fixed to the photo-
assembling an electrophotographic photosensitive sensitive drum constituting a process cartridge has been
member and process means acting on the electrophoto- 15 known (U.S. Patent No. 4,829,335).
graphic photosensitive member into a unit (cartridge) and [0010] However, in the conventional constitution de-
is mounted to and demounted from a main assembly of scribed in U.S. Patent No. 5,903,803, the rotatable mem-
the electrophotographic image forming apparatus. For ber is required to be moved in a horizontal direction when
example, the process cartridge is prepared by integrally the process cartridge is mounted to or demounted from
assembling the electrophotographic photosensitive 20 the main assembly by being moved in a direction sub-
member and at least one of a developing means, a charg- stantially perpendicular to an axial line of the rotatable
ing means, and a cleaning means as the process means member. That is, the rotatable member is required to be
into a cartridge. Accordingly, examples of the process horizontally moved by an opening and closing operation
cartridge include a process cartridge prepared by inte- of a main assembly cover provided to the apparatus main
grally assembling the electrophotographic photosensi- 25 assembly. By the opening operation of the main assem-
tive member and three process means consisting of the bly cover, the hole is moved apart from the projection.
developing means, the charging means, and the cleaning On the other hand, by the closing operation of the main
means into a cartridge; a process cartridge prepared by assembly cover, the hole is moved toward the projection
integrally assembling the electrophotographic photosen- so as to be engaged with the projection.
sitive member and the charging means as the process 30 [0011] Accordingly, in the conventional process car-
means into a cartridge; and a process cartridge prepared tridge, a constitution for moving the rotatable member in
by integrally assembling the electrophotographic photo- a rotational axis direction by the opening and closing op-
sensitive member and two process means consisting of eration of the.main assembly cover is required to be pro-
the charging means and the cleaning means. vided to the main assembly.
[0004] The process cartridge is detachably mountable 35 [0012] In the constitution described in U.S. Patent No.
to an apparatus main assembly by a user by himself (her- 4,829,335, without moving the driving gear provided to
self). Accordingly, maintenance of the apparatus can be the main assembly along the axial line direction thereof,
performed by the user by himself without relying on a the cartridge can be mounted to and demounted from
service person. As a result, operability of the mainte- the main assembly by being moved in a direction sub-
nance of the electrophotographic image forming appa- 40 stantially perpendicular to the axial line. However, in this
ratus. constitution a driving connection portion between the
main assembly and the cartridge is an engaging portion
[BACKGROUND ART] between gears, so that it is difficult to prevent rotation
non uniformity of the photosensitive drum.
[0005] In a conventional process cartridge, the follow- 45 [0013] Prior art can be found in document EP 1 178
ing constitution for receiving a rotational driving force, for 370 A, disclosing an image forming apparatus. The im-
rotating a drum shaped electrophotographic photosensi- age forming apparatus according to document EP 1 178
tive member (hereinafter referred to as a "photosensitive 370 A includes a process unit detachably mountable to
drum"), from an apparatus main assembly is known. a main assembly of the apparatus, the process unit in-
[0006] On a main assembly side, a rotatable member 50 cluding an image bearing member for bearing an elec-
for transmitting a driving force of a motor and a non cir- trostatic image and process means actable on the image
cular twisted hole, which is provided at a center portion bearing member, the process means having a rotational
of the rotatable member and has a cross section integrally shaft, a driving shaft, substantially co-axial with the rota-
rotatable with the rotatable member and provided with a tional shaft, for rotating the rotational shaft, and a drive
plurality of corners, are provided. 55 transmitting member, engaged with the driving shaft and
[0007] On a process cartridge side, a non circular twist- with the rotational shaft, for transmitting a driving force
ed projection, which is provided at one of longitudinal to the rotational shaft from the driving shaft, wherein the
ends of a photosensitive drum and has a cross section drive transmitting member is engaged with the driving
2
3 EP2 087 407B1 4
shaft with a play and is engaged with the rotational shaft process cartridge is detachably mountable.
with a play. [0019] A further object of the present invention is to
[0014] Further prior art can be found in document US provide a process cartridge mountable to and demount-
6 473 580 B1, disclosing a driving force receiving mem- able from a main assembly of an electrophotographic
ber, a shaft coupling, a toner image bearing member, a 5 image forming apparatus provided with a driving shaft in
process cartridge and an electrophotographic image a direction substantially perpendicular to an axial line of
forming apparatus. Further prior art can be found in doc- the driving shaft. A further object of the present invention
ument JP 5 341589 A, disclosing an image forming de- is to provide a photosensitive drum unit used in the proc-
vice. Further prior art can be found in document US ess cartridge and an electrophotographic image forming
2006/240896 A1, disclosing a constant-velocity joint and 10 apparatus to which the process cartridge is detachably
an image forming device. Further prior art can be found mountable.
in document JP 2004 045603 A, disclosing an image [0020] A further object of the present invention is to
forming apparatus. Further prior art can be found in doc- provide a process cartridge which compatibly realized
ument JP 1 164 818 A, disclosing an intershaft connect- that the process cartridge is demountable from a main
ing device. Further prior art can be found in document 15 assembly provided with a driving shaft in a direction sub-
JP 2002 031153 A, disclosing a coupling device and an stantially perpendicular to an axial line of the driving shaft
image forming device having the same. Further prior art and is capable of smoothly rotating the photosensitive
can be found in document US 2005/191092 A1, disclos- drum. A further object of the present invention is to pro-
ing an image forming apparatus. vide a photosensitive drum unit used in the process car-
20 tridge and an electrophotographic image forming appa-
[DISCLOSURE OF THE INVENTION] ratus to which the process cartridge is detachably mount-
able.
[0015] A principal object of the present invention is to [0021] A further object of the present invention is to
provide a process cartridge, a photosensitive drum unit provide a process cartridge which compatibly realizes
used in the process cartridge, and an electrophotograph- 25 that the process cartridge is mountable to a main assem-
ic image forming apparatus to which the process car- bly provided with a driving shaft in a direction substantially
tridge is detachably mountable, capable of solving the perpendicular to an axial line of the driving shaft and is
above described problems of the conventional process capable of smoothly rotating the photosensitive drum. A
cartridges. further object of the present invention is to provide a pho-
[0016] Another object of the present invention is to pro- 30 tosensitive drum unit used in the process cartridge and
vide a process cartridge capable of smoothly rotating a an electrophotographic image forming apparatus to
photosensitive drum by being mounted to a main assem- which the process cartridge is detachably mountable.
bly provided with no mechanism for moving a main as- [0022] A further object of the present invention is to
sembly side coupling member, in its axial line direction, provide a process cartridge which compatibly realizes
for transmitting a rotational force to the photosensitive 35 that the process cartridge is mountable to and demount-
drum by an opening and closing operation of a main as- able from a main assembly provided with a driving shaft
sembly cover. A further object of the present invention is in a direction substantially perpendicular to an axial line
to provide a photosensitive drum unit used in the process of the driving shaft and is capable of smoothly rotating
cartridge and an electrophotographic image forming ap- the photosensitive drum. A further object of the present
paratus to which the process cartridge is mountable and 40 invention is to provide a photosensitive drum unit used
from which the process cartridge is demountable. in the process cartridge and an electrophotographic im-
[0017] A further object of the present invention is to age forming apparatus to which the process cartridge is
provide a process cartridge demountable from a main detachably mountable.
assembly of an electrophotographic image forming ap- [0023] The above mentioned objects are achieved by
paratus provided with a driving shaft in a direction per- 45 what is defined in the appended independent claims. Ad-
pendicular to an axial line of the driving shaft. A further vantageous modifications thereof are set forth in the ap-
object of the present invention is to provide a photosen- pended dependent claims.
sitive drum unit used in the process cartridge and an elec- [0024] These and other objects, features, and advan-
trophotographic image forming apparatus to which the tages of the present invention will become more apparent
process cartridge is detachably mountable. 50 upon consideration of the following description of the pre-
[0018] A further object of the present invention is to ferred embodiments of the present invention, taken in
provide a process cartridge mountable to a main assem- conjunction with the accompanying drawings.
bly of an electrophotographic image forming apparatus
provided with a driving shaft in a direction substantially [BRIEF DESCRIPTION OF THE DRAWINGS]
perpendicular to an axial line of the driving shaft. A further 55
object of the present invention is to provide a photosen- [0025]
sitive drum unit used in the process cartridge and an elec-
trophotographic image forming apparatus to which the Figure 1 is a sectional side elevation of a cartridge
3
5 EP2 087 407B1 6
according to an embodiment of the present inven- Figure 21 is perspective views which illustrate a proc-
tion. ess of the engagement between the drive shaft and
Figure 2 is a perspective view of the cartridge ac- the coupling according to the embodiment of the
cording to the embodiment of the present invention. present invention.
Figure 3 is a perspective view of the cartridge ac- 5 Figure 22 is perspective views which illustrate a proc-
cording to the embodiment of the present invention. ess of the engagement between the drive shaft and
Figure 4 is a sectional side elevation of an apparatus the coupling according to the embodiment of the
main assembly according to the embodiment of the present invention.
present invention. Figure 23 is perspective views which illustrate the
Figure 5 is a perspective view and a longitudinal sec- 10 coupling of the apparatus main assembly and the
tional view of a drum flange (drum shaft) according coupling of the cartridge according to the embodi-
to the embodiment of the present invention. ment of the present invention.
Figure 6 is a perspective view of a photosensitive Figure 24 is an exploded perspective view which il-
drum according to the embodiment of the present lustrates the drive shaft, the driving gear, the cou-
invention. 15 pling, and the drum shaft according to the embodi-
Figure 7 is longitudinal sectional views of the photo- ment of the present invention.
sensitive drum according to the embodiment of the Figure 25 is perspective views which illustrate a proc-
present invention. ess of the disengagement of the coupling from the
Figure 8 is perspective views and a longitudinal sec- drive shaft according to the embodiment of the
tional view of a coupling according to the embodi- 20 present invention.
ment of the present invention. Figure 26 is perspective views which illustrate the
Figure 9 is perspective views of a drum bearing mem- coupling and the drum shaft according to the em-
ber according to the embodiment of the present in- bodiment of the present invention.
vention. Figure 27 is perspective views which illustrate the
Figure 10 is detailed views of a side surface of the 25 drum shaft according to the embodiment of the
cartridge according to the embodiment of the present present invention.
invention. Figure 28 is perspective views which illustrate a drive
Figure 11 is exploded perspective views and longi- shaft and a driving gear according to the embodiment
tudinal sectional views of the coupling and the bear- of the present invention.
ing member according to the embodiment of the 30 Figure 29 is perspective views which illustrate the
present invention. coupling according to the embodiment of the present
Figure 12 is a longitudinal sectional view after the invention, and side views.
assembling of the cartridge according to the embod- Figure 30 is exploded perspective views which illus-
iment of the present invention. trate the drum shaft, the drive shaft, and the coupling
Figure 13 is a longitudinal sectional view after the 35 according to the embodiment of the present inven-
assembling of the cartridge according to the embod- tion.
iment of the present invention. Figure 31 shows a side view and a longitudinal sec-
Figure 14 is a longitudinal sectional view of the car- tion of the side surface of the cartridge according to
tridge according to the embodiment of the present the embodiment of the present invention.
invention. 40 Figure 32 is a perspective view and a view, as seen
Figure 15 is perspective views which illustrate a com- from the device of the cartridge set portion of the
bined state of the drum shaft and the coupling. apparatus main assembly, according to he embod-
Figure 16 is perspective views which illustrate an iment of the present invention.
inclined state of the coupling. Figure 33 is longitudinal sectional views which illus-
Figure 17 is perspective views and a longitudinal 45 trate a dismounting process from the apparatus main
sectional view of a driving structure of the apparatus assembly of the cartridge according to the embodi-
main assembly according to the embodiment of the ment of the present invention.
present invention. Figure 34 is longitudinal sectional views which illus-
Figure 18 is a perspective view of a cartridge set trate a mounting process to the apparatus main as-
portion of the apparatus main assembly according 50 sembly of the cartridge according to the embodiment
to the embodiment of the present invention. of the present invention.
Figure 19 is a perspective view of the cartridge set Figure 35 is perspective views which illustrate phase
portion of the apparatus main assembly according control means for a drive shaft according to a second
to the embodiment of the present invention. embodiment of the present invention.
Figure 20 is sectional views which illustrate a proc- 55 Figure 36 is perspective views which illustrate a
ess of the mounting of the cartridge to the apparatus mounting operation of a cartridge according to the
main assembly according to the embodiment of the embodiment of the present invention.
present invention. Figure 37 is perspective views of a coupling accord-
4
7 EP2 087 407B1 8
ing to the embodiment of the present invention. tween a drive shaft and the coupling according to
Figure 38 is top plan views of a mounted state of the the embodiment of the present invention.
cartridge as seen in a mounting direction according Figure 54 is an exploded perspective view which il-
to the embodiment of the present invention. lustrates a cartridge before assembling the major
Figure 39 is perspective views which illustrate a drive 5 members according to a sixth embodiment of the
stop state of the process cartridge (photosensitive present invention.
drum) according to the embodiment of the present Figure 55 is a side view which illustrates a driving
invention. side according to the embodiment of the present in-
Figure 40 is longitudinal sectional views and per- vention.
spective views which illustrate a dismounting oper- 10 Figure 56 is schematic longitudinal sectional views
ation of the process cartridge according to the em- of a drum shaft and a coupling according to the em-
bodiment of the present invention. bodiment of the present invention.
Figure 41 is a sectional view which illustrates the Figure 57 is longitudinal sectional views which illus-
state where a door provided in an apparatus main trate the engagement between a drive shaft and cou-
assembly is opened according to a third embodiment 15 pling according to the embodiment of the present
of the present invention. invention.
Figure 42 is a perspective view which illustrates a Figure 58 is sectional views which illustrate a mod-
mounting guide of a driving side of the apparatus ified example of a coupling locking member accord-
main assembly according to the embodiment of the ing to the embodiment of the present invention.
present invention. 20 Figure 59 is a perspective view which illustrates an
Figure 43 is a side view of the driving side of the attaching state of a magnet member to a drum bear-
cartridge according to the embodiment of the present ing member according to a seventh embodiment of
invention. the present invention.
Figure 44 is a perspective view as seen from the Figure 60 is an exploded perspective view which il-
driving side of the cartridge according to the embod- 25 lustrates the drum bearing member, a coupling, and
iment of the present invention. a drum shaft according to the embodiment of the
Figure 45 is side view which illustrates an inserting present invention.
state of the cartridge to the apparatus main assembly Figure 61 is a.perspective view which illustrates a
according to the embodiment of the present inven- driving side of the cartridge according to the embod-
tion. 30 iment of the present invention.
Figure 46 is a perspective view which illustrates an Figure 62 is perspective views and longitudinal sec-
attaching state of a locking member to a drum bear- tional views which illustrate an engaged state be-
ing member according to a fourth embodiment of the tween a drive shaft and coupling according to the
present invention. embodiment of the present invention.
Figure 47 is an exploded perspective view which il- 35 Figure 63 is a perspective view which illustrates the
lustrates the drum bearing member, a coupling, and driving side of a cartridge according to an eighth em-
a drum shaft according to the embodiment of the bodiment of the present invention.
present invention. Figure 64 is n exploded perspective views which il-
Figure 48 is a perspective view which illustrates a lustrate a state before the assembly of a bearing
driving side of the cartridge according to the embod- 40 member according to the embodiment of the present
iment of the present invention. invention.
Figure 49 is perspective views and longitudinal sec- Figure 65 is longitudinal sectional views which illus-
tional views which illustrate an engaged state be- trate the structures of a drum shaft, a coupling, and
tween a drive shaft and a coupling according to the a bearing member according to the embodiment of
embodiment of the present invention. 45 the present invention.
Figure 50 is an exploded perspective view which il- Figure 66 is a perspective view which illustrates a
lustrates a state where a pressing member was driving side of an apparatus main assembly guide
mounted to a drum bearing member according to a according to the embodiment of the present inven-
fifth embodiment of the present invention. tion.
Figure 51 is exploded perspective views which illus- 50 Figure 67 is longitudinal sectional views which illus-
trate the drum bearing member, a coupling, and a trate a disengagement state of a locking member
drum shaft according to the embodiment of the according to the embodiment of the present inven-
present invention. tion.
Figure 52 is a perspective view which illustrates the Figure 68 is longitudinal sectional views which illus-
driving side of a cartridge according to the embodi- 55 trate the engagement between a drive shaft and a
ment of the present invention. coupling according to the embodiment of the present
Figure 53 is perspective views and longitudinal sec- invention.
tional views which illustrate an engaged state be- Figure 69 is side views which illustrate a driving side
5
9 EP2 087 407B1 10
of a cartridge according to a ninth embodiment of Figure 85 is perspective views and sectional views
the present invention. of a coupling according to a twelfth embodiment of
Figure 70 is a perspective view which illustrates a the present invention.
driving side of an apparatus main assembly guide Figure 86 is perspective views which illustrate a cou-
according to the embodiment of the present inven- 5 pling according to a thirteenth embodiment of the
tion. present invention.
Figure 71 is side views which illustrate a relation be- Figure 87 is a sectional view which illustrates a drum
tween the cartridge and the main assembly guide shaft, a drive shaft, the coupling, and an urging mem-
according to the embodiment of the present inven- ber according to the embodiment of the present in-
tion. 10 vention.
Figure 72 is perspective views which illustrate a re- Figure 88 is sectional views which illustrate the drum
lation between the main assembly guide and the cou- shaft, the coupling, a bearing member, and the drive
pling according to the embodiment of the present shaft according to the embodiment of the present
invention. invention.
Figure 73 is side views, as seen from the driving side, 15 Figure 89 is a perspective view which illustrates a
which illustrate a process of the mounting to the main drum shaft and a coupling according to a 14th em-
assembly of the cartridge, according to the embod- bodiment of the present invention.
iment of the present invention. Figure 90 is perspective views which illustrate a proc-
Figure 74 is a perspective view which illustrates a ess of the engagement between a drive shaft and
driving side of a main assembly guide according to 20 coupling according to the embodiment of the present
a tenth embodiment of the present invention. invention.
Figure 75 is a side view which illustrates a relation Figure 91 is perspective views and sectional views
between the main assembly guide and a coupling which illustrate a drum shaft, a coupling, and a bear-
according to the embodiment of the present inven- ing member according to a 15th embodiment of the
tion. 25 present invention.
Figure 76 is a perspective view which illustrates a Figure 92 is perspective views which illustrate a sup-
relation between the main assembly guide and the porting method for a coupling (mounting method) ac-
coupling according to the embodiment of the present cording to a 16th embodiment of the present inven-
invention. tion.
Figure 77 is a side view which illustrates a relation 30 Figure 93 is perspective views which illustrate a sup-
between the cartridge and the main assembly guide porting method for a coupling (mounting method) ac-
according to the embodiment of the present inven- cording to a 17th embodiment of the present inven-
tion. tion.
Figure 78 is perspective views which illustrate a re- Figure 94 is a perspective view of a cartridge accord-
lation between the main assembly guide and the cou- 35 ing to an embodiment of the present invention.
pling according to the embodiment of the present Figure 95 illustrates only a coupling according to the
invention. embodiment of the present invention.
Figure.79 is a side view which illustrates a relation Figure 96 illustrates a drum flange having a coupling
between the main assembly guide and the coupling according to an embodiment of the present inven-
according to the embodiment of the present inven- 40 tion.
tion. Figure 97 is sectional views taken along S22-S22 of
Figure 80 is a perspective view which illustrates a Figure 84.
relation between the main assembly guide and the Figure 98 is a sectional view of a photosensitive drum
coupling according to the embodiment of the present unit according to an embodiment of the present in-
invention. 45 vention.
Figure 81 is a side view which illustrates a relation Figure 99 is a sectional view taken along S23-S23
between the main assembly guide and the coupling of Figure 85.
according to the embodiment of the present inven- Figure 100 is perspective views which illustrate a
tion. combined state of a drum shaft and a coupling ac-
Figure 82 is a perspective view and a sectional view 50 cording to an embodiment of the present invention.
of a coupling according to an eleventh embodiment Figure 101 is perspective views which illustrate an
of the present invention. inclined state of a coupling according to an embod-
Figure 83 is a perspective view and a sectional view iment of the present invention.
of the coupling according to the embodiment of the Figure 102 is perspective views which illustrate a
present invention. 55 process of the engagement between a drive shaft
Figure 84 is a perspective view and a sectional view and a coupling according to an embodiment of the
of the coupling according to the embodiment of the present invention.
present invention. Figure 103 is perspective views which illustrate a
6
11 EP2 087 407B1 12
process of the engagement between a drive shaft The photosensitive drum 107 is rotated by receiving a
and a coupling according to an embodiment of the rotational force from the apparatus main assembly A by
present invention. a coupling mechanism when the cartridge B is mounted
Figure 104 is an exploded perspective view which in the apparatus main assembly A as shown in Figure 4.
illustrates a drive shaft, a driving gear, a coupling, 5 The cartridge B is mountable to and demountable from
and a drum shaft according to an embodiment of the the apparatus main assembly A by a user.
present invention. [0029] A charging roller 108 as a charging means
Figure 105 is perspective views which illustrate a (process means) is provided in contact with an outer pe-
process of the disengagement of a coupling from a ripheral surface of the photosensitive drum 107. The
drive shaft according to an embodiment of the 10 charging roller 108 electrically charges the photosensi-
present invention. tive drum 107 by voltage application from the apparatus
Figure 106 is perspective views which illustrate a main assembly A. The charging roller 108 is rotated by
combined state between a drum shaft and a coupling the rotation of the photosensitive drum 107.
according to an embodiment of the present inven- [0030] The cartridge B includes a developing roller 110
tion. 15 as a developing means (process means). The developing
Figure 107 is perspective views which illustrate a roller 110 supplies a developer to a developing area of
combined state between a drum shaft and a coupling the photosensitive drum 107. The developing roller 110
according to an embodiment of the present inven- develops an electrostatic latent image formed on the pho-
tion. tosensitive drum 107 with the developer t. The develop-
Figure 108 is perspective views showing a combined 20 ing roller 110 contains therein a magnet roller (fixed mag-
state between a drum shaft and a coupling according net) 111. In contact with a peripheral surface of the de-
to an embodiment of the present invention. veloping roller 110, a developing blade 112 is provided.
Figure 109 is a perspective view of a first frame unit The developing blade 112 defines an amount of the de-
which has a photosensitive drum, as seen from the veloper t to be deposited on the peripheral surface of the
driving side, according to an embodiment of the 25 developing roller 110. The developing blade 112 imparts
present invention. triboelectric charges to the developer t.
Figure 110 is a perspective view which illustrates a [0031] The developer t contained in a developer ac-
drum shaft and a coupling according to an embodi- commodating container 114 is sent to a developing
ment of the present invention. chamber 113a by rotation of stirring members 115 and
Figure 111 is a sectional view taken along S20 - S20 30 116, so that the developing roller 110 supplied with a
in Figure 79. voltage is rotated. As a result, a developer layer to which
Figure 112 is a perspective view of a photosensitive the electric charges are imparted by the developing blade
drum unit according to an embodiment of the present 112 is formed on the surface of the developing roller 110.
invention. The developer t is transferred onto the photosensitive
35 drum 107 depending on the latent image. As a result, the
[BEST MODE FOR CARRYING OUT THE INVENTION] latent image is developed.
[0032] The developer image formed on the photosen-
[0026] The process cartridge and an electrophoto- sitive drum 107 is transferred onto a recording medium
graphic image forming apparatus according to according 102 by a transfer roller 104. The recording medium 102
to an embodiment of the present invention will be de- 40 is used for forming an image of the developer thereon
scribed. and, e.g., is recording paper, label, OHP sheet, and so on
[0033] In contact with the outer peripheral surface of
[Embodiment 1] the photosensitive drum 107, an elastic cleaning blade
117a as a cleaning means (process means) is disposed.
(1) Brief description of process cartridge. 45 The cleaning blade 117a elastically contacts the photo-
sensitive drum 107 at its end and removes the developer
[0027] A process cartridge B to which an embodiment t remaining on the photosensitive drum 107 after the de-
of the present invention is applied will be described with veloper image is transferred onto the recording medium
reference to Figures 1 to 4. Figure 1 is a sectional view 102. The developer t removed from the surface of the
of the cartridge B. Figures 2 and 3 are perspective views 50 photosensitive drum 107 by the cleaning blade 117a is
of the cartridge B. Figure 4 is a sectional view of an elec- accommodated in a removed developer reservoir 117b.
trophotographic image forming apparatus main assem- [0034] The cartridge B is integrally constituted by a first
bly A (hereinafter referred to as an "apparatus main as- frame unit 119 and a second frame unit 120.
sembly A"). The apparatus main assembly A corre- [0035] The first frame unit.119 is constituted by a first
sponds to a portion of the electrophotographic image 55 frame 113 as a part of a cartridge frame B1. The first
forming apparatus from which the cartridge B is excluded. frame unit 119 includes the developing roller 110, the
[0028] Referring to Figures 1 to 3, the cartridge B in- developing blade 112, the developing chamber 113a, the
cludes an electrophotographic photosensitive drum 107. developer accommodating container 114, and the stirring
7
13 EP2 087 407B1 14
members 115 and 116. As a result, on the recording medium 102, an image is
[0036] The second frame unit 120 is constituted by a formed. Thereafter, the recording medium 102 is con-
second frame 118 as a part of the cartridge frame B1. veyed by roller pairs 103g and 103h and discharged on
The second frame unit 120 includes the photosensitive a tray 106. The above described roller 103b, the convey-
drum 107, the cleaning blade 117a, the removed devel- 5 ing roller pairs 103c, 103d and 103e, the guide 103f, the
oper reservoir 117b, and the charging roller 108. roller pairs 103g and 103h, and the like constitute a con-
[0037] The first frame unit 119 and the second frame veying means 103 for conveying the recording medium
unit 120 are rotatably connected with each other by a pin 102.
P. By an elastic member 135 (Figure 3) provided between [0044] The cartridge mounting portion 130a is a portion
the first and second frame units 119 and 120, the devel- 10 (space) for mounting the cartridge B therein. In a state
oping roller 110 is pressed against the photosensitive in which the cartridge B is positioned in the space, the
drum 107. coupling member 150 (described later) of the cartridge
[0038] The user attaches (mounts) the cartridge B to B is connected with the driving shaft of the apparatus
a cartridge mounting portion 130a of the apparatus main main assembly A. In this embodiment, the mounting of
assembly A by gripping a grip. During the mounting, as 15 the cartridge B to the mounting portion 130a is referred
described later, a driving shaft 180 (Figure 17) of the to as mounting of the cartridge B to the apparatus main
apparatus main assembly A and a coupling member 150 assembly A. Further, demounting (removal) of the car-
(described later) as a rotational force transmitting part of tridge B from the mounting portion 130b is referred to as
the cartridge B are connected with each other in synchro- demounting of the cartridge B from the apparatus main
nism with the mounting operation of the cartridge B. The 20 assembly A.
photosensitive drum 107 or the like is rotated by receiving
the rotational force from the apparatus main assembly A. (3) Description of constitution of drum flange
(2) Description of electrophotographic image forming ap- [0045] First, a drum flange at a side where the rota-
paratus 25 tional force is transmitted from the apparatus main as-
sembly A to the photosensitive drum 107 (hereinafter
[0039] With reference to Figure 4, the electrophoto- simply referred to a "drive side") will be described with
graphic image forming apparatus using the above de- reference to Figure 5. Figure 5(a) is a perspective view
scribed cartridge B will be described. of the drum flange at the drive side and Figure 5(b) is a
[0040] In the following, a laser beam printer will be de- 30 sectional view of the drum flange taken along S1 - S1
scribed as an example of the apparatus main assembly A. line shown in Figure 5(a). Incidentally, with respect to an
[0041] During image formation, the surface of the ro- axial line direction of the photosensitive drum, a side op-
tating photosensitive drum 107 is electrically charged uni- posite from the drive side is referred to as a "non- drive
formly by the charging roller 108. Then, the surface of side").
the photosensitive drum 107 is irradiated with laser light, 35 [0046] A drum flange 151 is formed of a resinous ma-
depending on image information, emitted from an optical terial by ejection molding. Examples of the resinous ma-
means 101 including unshown members such as a laser terial may include polyacetal, polycarbonate, and so on
diode, a polygonal mirror, a lens, and a reflecting mirror. A drum shaft 153 is formed of a metallic material such
As a result, on the photosensitive drum 107, an electro- as iron, stainless steel, or the like. Depending on a load
static latent image depending on the image information 40 torque for rotating the photosensitive drum 107, it is pos-
is formed. The latent image is developed by the above sible to select appropriately the materials for the drum
described developing roller 110. flange 151 and the drum shaft 153. For example, the
[0042] On the other hand, in synchronism with the im- drum flange 151 may also be formed of the metallic ma-
age formation, the recording medium 102 set in a cas- terial and the drum shaft 153 may also be formed of the
sette 103a is conveyed to a transfer position by a feeding 45 resinous material. When both of the drum flange 151 and
roller 103b and conveying roller pairs 103c, 103d and the drum shaft 153 are formed of the resinous material,
103e. At the transfer position, the transfer roller 104 as they can be integrally molded.
a transfer means is disposed. To the transfer roller 104, [0047] The flange 151 is provided with an engaging
a voltage is applied. As a result, the developer image portion 151a which engages with an inner surface of the
formed on the photosensitive drum 107 is transferred on- 50 photosensitive drum 107, a gear portion (helical gear or
to the recording medium 102. spur gear) 151c for transmitting a rotational force to the
[0043] The recording medium 102 onto which the de- developing roller 110, and an engaging portion 151d ro-
veloper image is transferred is conveyed to a fixing tatably supported on a drum bearing. More specifically,
means 105 through a guide 103f. The fixing means 105 as for the flange 151, the engaging portion 151a engages
includes a driving roller 105c and a fixing roller 105b con- 55 with one end of a cylindrical drum 107a as will be de-
taining therein a heater 105a. To the passing recording scribed hereinafter. These are disposed co-axially with
medium 102, heat and pressure are applied, so that the a rotation axis L1 of the photosensitive drum 107. And,
developer image is fixed on the recording medium 102. the drum engaging portion 151a has a cylindrical shape,
8
15 EP2 087 407B1 16
and a base 151b perpendicular thereto is provided. The limit the present invention.
base 151b is provided with a drum shaft 153 outwardly [0050] In addition, a space portion 151e formed by the
projected with respect to the direction of the axis L1. This engaging portion 151d and the base 151b receives a part
drum shaft 153 is co-axial with the drum engaging portion of drum coupling member 150, in mounting the drum cou-
151a. These are fixed so as to be co-axial with the rotation 5 pling member 150 (which will be described hereinafter)
axis L1. As for the fixing method thereof the press-fitting, to the flange 151.
the bonding, the insert molding, and so on are available, [0051] In this embodiment, the gear portion 151a for
and they are selected properly. transmitting the rotational force to the developing roller
[0048] The drum shaft 153 comprises the circular col- 110 is mounted to the flange 151.. However, the rotation
umn portion 153a which has a projection configuration, 10 of the developing roller 110 may be transmitted not
and is disposed so as to be co-axially with the rotation through the flange 151. In that case, the gear portion
axis of the photosensitive drum 107. The drum shaft 153 151c is unnecessary. However, in the case of disposing
is provided on the end part of the photosensitive drum the gear portion 151a at the flange 151, integral molding,
107 on the axis L1 of the photosensitive drum 107. In with the flange 151, of the gear portion 151a can be uti-
addition, the drum shaft 153 is about 5 - 15mm in diameter 15 lized.
in consideration of the material, the load, and the space. [0052] The flange 151, the drum shaft 153, and the pin
A free end portion 153b of the circular column portion 155 function as the rotational force receiving member
153a has a semi-spherical surface configuration so that which receives the rotational force from the drum cou-
it can incline smoothly, when an axis of a drum coupling pling member 150 as will be described hereinafter.
member 150 which is a rotating force transmitting portion 20
inclines, as will be described in detail hereinafter. In ad- (4) Structure of electrophotographic photosensitive
dition, in order to receive the rotational force from the member drum unit
drum coupling member 150, a rotating force transmitting
pin (rotating force receiving member (portion) 155 are [0053] Referring to Figure 6 and Figure 7, the structure
provided on the photosensitive drum 107 side of the free 25 of an electrophotographic photosensitive member drum
end of the drum shaft 153. The pin 155 is extended in unit ("drum unit") will be described. Figure 6 (a) is a per-
the direction substantially perpendicular to the axis of the spective view, as seen from the driving side, of the drum
drum shaft 153. unit U1, and Figure 6 (b) is a perspective view as seen
[0049] The pin 155 as the rotational force receiving from the non-driving side. In addition, Figure 7 is a sec-
member has a cylindrical shape which has a diameter 30 tional view taken along S2-S2 of Figure 6 (a).
smaller than that of the circular column portion 153a of [0054] The photosensitive drum 107 has a cylindrical
the drum shaft 153, and is made of the metal or the resin drum 107a coated with a photosensitive layer 107b on
material. And, it is fixed by press-fitting, bonding, and so the peripheral surface.
on to the drum shaft 153. And, the pin 155 is fixed in the [0055] The cylindrical drum 107a has an electrocon-
direction which the axis thereof intersects the axis L1 of 35 ductive cylinder, such as the aluminum, and the photo-
the photosensitive drum 107. Preferably, it is desirable sensitive layer 107b applied thereon. The opposite ends
to dispose the axis of the pin 155 so as to pass the center thereof are provided with the drum surface and the sub-
P2 of the spherical surface of the free end portion 153b stantially co-axial opening 107a1, 107a2, in order to en-
of the drum shaft 153 (figure 5 (b)). Although the free end gage the drum flange (151, 152). More particularly, the
portion 153b is the semi-spherical surface configuration 40 drum shaft 153 is provided on the end part of the cylin-
actually, the center P2 is the center of a phantom spher- drical drum 107a co-axially with the cylindrical drum
ical surface that the semispherical surface makes the 107a. Designated by 151c is a gear and transmits a ro-
part thereof. In addition, the number of the pins 155 can tational force which the coupling 150 received from a
be selected properly. In this embodiment, a single pin drive shaft 180 to a developing roller 110. The gear 151c
155 is used from the standpoint of the assembling prop- 45 is integrally molded with the flange 15.
erty and in order to transmit driving torque assuredly. The [0056] The cylinder 107a may be hollow or solid.
pin 155 passes said center P2, and is through the drum [0057] As to the drum flange 151 of the driving side,
shaft 153. And, the pin 155 is outwardly projected at the since it has been described in the foregoing, the descrip-
positions of the peripheral surface of the drum shaft 153 tion is omitted.
which are diametrically opposite (155a1, 155a2). More 50 [0058] A drum flange 152 of the non-driving side is
particularly, the pin 155 is projected in the direction per- made of the resin material similarly to the driving side
pendicular to the axis (axis L1) of the drum shaft 153 with injection molding. And, a drum engaging portion
relative to the drum shaft 153 at the two opposite places 152b and a bearing portion 152a are substantially co-
(155a1, 155a2). By this, the drum shaft 153 receives the axially disposed with each other. In addition, the flange
rotational force from the drum coupling member 150 at 55 152 is provided with a drum grounding plate 156. The
the two places. In this embodiment, the pin 155 is mount- drum grounding plate 156 is an electroconductive thin
ed to the drum shaft 153 in the range of 5mm from the plate (metal). The drum grounding plate 156 includes
free end of the drum shaft 153. However, this does not contact portions 156b1, 156b2 which contact the inner
9
17 EP2 087 407B1 18
surface of the electroconductive cylindrical drum 107a, it is engaged with the drive shaft 180. In addition, the
and a contact portion 156a which contacts the drum coupling 150 transmits the rotational force thereof to the
grounding shaft 154 (which will be described hereinafter). photosensitive drum 107. The materials available for the
And, for the purpose of grounding the photosensitive coupling 150 are the resin materials, such as polyacetal
drum 107, the drum grounding plate 156 is electrically 5 and the polycarbonate PPS. However, in order to raise
connected with the apparatus main assembly A. a rigidity of the coupling 150, the glass fibers, the carbon
[0059] A drum flange 152 of the non-driving side is fibers, and so on may be mixed in the above described
made of the resin material, similarly to the driving side resin material correspondingly to a required load torque.
with injection molding. And, a drum engaging portion In the case of mixing said material, the rigidity of the cou-
152b and a bearing portion 152a are substantially co- 10 pling 150 can be raised. In addition, in the resin material,
axially disposed with each other. In addition, the flange the metal may be inserted, then the rigidity may further
152 is provided with a drum grounding plate 156. The be raised, and the whole coupling may be manufactured
drum grounding plate 156 is an electroconductive thin from the metal and so on.
plate (metal). The drum grounding plate 156 includes [0064] The coupling 150 mainly comprises three por-
contact portions 156b1, 156b2 which contact the inner 15 tions.
surface of the electroconductive cylindrical drum 107a, [0065] The first portion is engageable with the drive
and a contact portion 156a which contacts the drum shaft 180 (which will be described hereinafter), and it is
grounding shaft 154 (which will be described hereinafter). a coupling side driven portion 150a for receiving the ro-
And, for the purpose of grounding the photosensitive tational force from the rotational force transmitting pin
drum 107, the drum grounding plate 156 is electrically 20 182 which is a rotational force applying portion (main
connected with the apparatus main assembly A. assembly side rotational force transmitting portion) pro-
[0060] Although it has been described that the drum vided on the drive shaft 180. In addition, the second por-
grounding plate 156 is provided in the flange 152, the tion is engageable with the pin 155, and it is a coupling
present invention is not limited to such an example. For side driving portion 150b for transmitting the rotational
example, the drum grounding plate 156 may be disposed 25 force to the drum shaft 153. In addition, the third portion
at the drum flange 151, and it is possible to select properly is a connecting portion 150c for connecting the driven
the position which can be connected with the ground. portion 150a and the driving portion 150b with each other
[0061] Thus, the drum unit U1 comprises the photo- (Figure 8 (c) and (f)).
sensitive drum 107 which has the cylinder 107a, the [0066] The driven portion 150a, the driving portion
flange 151, the flange 152, the drum shaft 153, the pin 30 150b, and the connecting portion 150c may be molded
155, and the drum grounding plate 156. integrally, or, alternatively, the separate parts may be
connected with each other. In this embodiment, these
(5) Rotational force transmitting portion (drum coupling are integrally molded with resin material. By this, the man-
member) ufacturing of the coupling 150 is easy and the accuracy
35 as the parts is high. As shown in Figure 8(f) the driven
[0062] The description will be made, referring to Figure portion 150a is provided with a drive shaft insertion open-
8 as to an example of the drum coupling member which ing portion 150m which expands toward the rotation axis
is the rotational force transmitting portion. Figure 8 (a) is L2 of the coupling 150. The driving portion 150b has a
a perspective view, as seen from the apparatus main drum shaft insertion opening portion 1501. which ex-
assembly side, of the drum coupling member, Figure 8 40 pands toward the rotation axis L2.
(b) is a perspective view, as seen from the photosensitive [0067] The opening 150m has a conical driving shaft
drum side, of the drum coupling member, and Figure 8 receiving surface 150f as an expanded part which ex-
(c) is a view seen in the direction perpendicular to the pands toward the drive shaft 180 side in the state where
direction of the coupling rotation shaft L2. In addition, the coupling 150 is mounted to the apparatus main as-
Figure 8 (d) is the side view, as seen from the apparatus 45 sembly A. The receiving surface 150f constitutes a re-
main assembly side, of the drum coupling member, Fig- cess 150z as shown in Figure 8 (f). The recess 150z
ure 8 (e) is the Figure, as seen from the photosensitive includes the opening 150m at a position opposite the side
drum side, and Figure 8 (f) is a sectional view taken along adjecent the photosensitive drum 107 with respect to the
S3 in Figure 8 (d). direction of the axis L2.
[0063] The drum coupling member ("coupling") 150 en- 50 [0068] By this, regardless of rotation phase of the pho-
gages with a drive shaft 180 (Figure 17) of the apparatus tosensitive drum 107 in the cartridge B, the coupling 150
main assembly A in the state where the cartridge B is can pivot among a rotational force transmitting angular
mounted set to the installation section 130a. In addition, position, a pre-engagement angular position, and a dis-
the coupling 150 is disengaged from the drive shaft 180, engaging angular position relative to the axis L1 of the
when the cartridge B is taken out from the apparatus 55 photosensitive drum 107 without being prevented by the
main assembly A. And, the coupling 150 receives a ro- free end portion of the drive shaft 180. The rotational
tational force from a motor provided in the apparatus main force transmitting angular position, the pre-engagement
assembly A through the drive shaft 180 in the state where angular position, and the disengaging angular position
10