EP0458273A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Charging device, image forming apparatus with same and a process unit detachable mountable to the image forming apparatus
Assignee: Canon Inc
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Filing: 1991-05-21
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Granted: —
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Expires: 2011-05-21
Abstract
Abstract A charging apparatus includes a charging member (2) contactable to an image bearing member, the charging member including a base member (2a) and an elastic coating layer (2b) which is on the base member (2a) and contactable to an image bearing member (1) which is the member to be charged; a pressing device (4) for pressing the coating layer (2a) to the image bearing member (1); wherein the coating layer (2a) has a thickness which is larger away from the pressing device (4) when the coating layer (2a) is not press-contacted to the image bearing member (1).
Inventors
- 👤 Tatsunori c/o Canon Kabushiki Kaisha Ishiyama
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-27 23:23
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/02; G03G15/0208; G03G15/0216; G03G15/0233
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
80 words
A charging apparatus, comprising: a charging member contactable to a member to be charged, said charging member including a base member and an elastic coating layer which is on said base member and contactable to the member to be charged; pressing means for pressing the coating layer to the image bearing member; wherein the coating layer has a thickness which is larger away from said pressing means when the coating layer is not press-contacted to the member to be charged.
Claim 2
Dependent Claim
20 words
An apparatus according to Claim 1, wherein the pressing means applies pressure at longitudinally opposite ends of the charging member.
Claim 3
Dependent Claim
23 words
An apparatus according to Claim 2, wherein the thickness of the coating layer is larger toward a longitudinally center of the charging member.
Claim 4
Dependent Claim
18 words
An apparatus according to Claim 1, wherein said charging member is in the form of a rotatable roller.
Claim 5
Dependent Claim
44 words
An apparatus according to Claim 4, wherein said pressing means applies pressure at longitudinally opposite ends of said charging member, and wherein an outer diameter of the roller increases toward the longitudinal center of the roller from each of the opposite longitudinal ends thereof.
Claim 6
Dependent Claim
39 words
An apparatus according to Claim 5, wherein the outer diameter R1 adjacent the longitudinal central portion of the charging roller is larger than that adjacent longitudinally opposite ends by not less than 0.3 % and less than 5 %.
Claim 7
Dependent Claim
40 words
An apparatus according to Claim 1, wherein said coating layer has an electrically conductive elastic layer and a surface layer contactable to the image bearing member and having a volume resistivity which is larger than that of the elastic layer.
Claim 8
Dependent Claim
51 words
An apparatus according to Claim 1 or 5, wherein the coating layer has a thickness at a position most remote from a position where said pressing means applies pressure to said charging member is larger than that adjacent the position by not less than 0.5 % and less than 3 %.
Claim 9
Dependent Claim
63 words
An apparatus according to Claim 5, wherein (R1-R) is larger than (R2-R) by not less than 0.5 % and less than 5 % where R is an outer diameter of said base member, R1 is an outer diameter of said charging roller adjacent longitudinally central portion thereof, and R2 is an outer diameter of said charging roller adjacent a longitudinal end portion thereof.
Claim 10
Dependent Claim
26 words
An apparatus according to Claim 1, 6, 8 or 9, wherein an oscillating voltage is applied between the member to be charged and said charging member.
Claim 11
Dependent Claim
34 words
An apparatus according to Claim 10, wherein said oscillating voltage has a peak-to-peak voltage which is not less than twice a charge starting voltage between the member to be charged and said charging member.
Claim 12
Dependent Claim
94 words
An image forming apparatus, comprising: an image bearing member; image forming means for forming an image on said image bearing member; a charging member contactable to said image bearing member, said charging member including a base member and an elastic coating layer which is on said base member and contactable to said image bearing member; pressing means for pressing the coating layer to said image bearing member; wherein the coating layer has a thickness which is larger away from said pressing means when the coating layer is not press-contacted to said image bearing member.
Claim 13
Dependent Claim
20 words
An apparatus according to Claim 12, wherein the pressing means applies pressure at longitudinally opposite ends of the charging member.
Claim 14
Dependent Claim
23 words
An apparatus according to Claim 13, wherein the thickness of the coating layer is larger toward a longitudinally center of the charging member.
Claim 15
Dependent Claim
18 words
An apparatus according to Claim 12, wherein said charging member is in the form of a rotatable roller.
Claim 16
Dependent Claim
44 words
An apparatus according to Claim 15, wherein said pressing means applies pressure at longitudinally opposite ends of said charging member, and wherein an outer diameter of the roller increases toward the longitudinal center of the roller from each of the opposite longitudinal ends thereof.
Claim 17
Dependent Claim
39 words
An apparatus according to Claim 16, wherein the outer diameter R1 adjacent the longitudinal central portion of the charging roller is larger than that adjacent longitudinally opposite ends by not less than 0.3 % and less than 5 %.
Claim 18
Dependent Claim
40 words
An apparatus according to Claim 12, wherein said coating layer has an electrically conductive elastic layer and a surface layer contactable to the image bearing member and having a volume resistivity which is larger than that of the elastic layer.
Claim 19
Dependent Claim
51 words
An apparatus according to Claim 12 or 16, wherein the coating layer has a thickness at a position most remote from a position where said pressing means applies pressure to said charging member is larger than that adjacent the position by not less than 0.5 % and less than 3 %.
Claim 20
Dependent Claim
63 words
An apparatus according to Claim 16, wherein (R1-R) is larger than (R2-R) by not less than 0.5 % and less than 5 % where R is an outer diameter of said base member, R1 is an outer diameter of said charging roller adjacent longitudinally central portion thereof, and R2 is an outer diameter of said charging roller adjacent a longitudinal end portion thereof.
Claim 21
Dependent Claim
15 words
An apparatus according to Claim 12, wherein said image forming means uses said charging member.
Claim 22
Dependent Claim
24 words
An apparatus according to Claim 12, 17, 19 or 20, wherein said image forming means forms a toner image on said image bearing member.
Claim 23
Dependent Claim
13 words
An apparatus according to Claim 22, wherein the toner is styrene acrylic toner.
Claim 24
Dependent Claim
16 words
An apparatus according to Claim 22, wherein said image bearing member has an organic photoconductive layer.
Claim 25
Dependent Claim
16 words
An apparatus according to Claim 23, wherein said image bearing member has an organic photoconductive layer.
Claim 26
Dependent Claim
22 words
An apparatus according to Claim 22, wherein an oscillating voltage is applied between the member to be charged and said charging member.
Claim 27
Dependent Claim
34 words
An apparatus according to Claim 26, wherein said oscillating voltage has a peak-to-peak voltage which is not less than twice a charge starting voltage between the member to be charged and said charging member.
Claim 28
Dependent Claim
32 words
An apparatus according to Claim 12, further comprising a process unit containing said image bearing member and said charging member, wherein said process unit is detachably mountable to said image forming apparatus.
Claim 29
Dependent Claim
96 words
A process unit detachably mountable to an image forming apparatus, comprising: an image bearing member; a charging member contactable to a member to be charged, said charging member including a base member and an elastic coating layer which is on said base member and contactable to an image bearing member which is the member to be charged; pressing means for pressing the coating layer to the image bearing member; wherein the coating layer has a thickness which is larger away from said pressing means when the coating layer is not press-contacted to the image bearing member.
References Cited (Backward Citations)
No citation records indexed.
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