Patent US5600421A successfully refreshed from Google Patents.
US5600421A
Expired / Lapsed
US
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Image forming apparatus
Assignee: Canon Inc
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Filing: 1994-09-14
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Granted: 1997-02-04
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Expires: 2014-09-14
Abstract
Abstract The present invention provides an image forming apparatus comprising an image bearing member for bearing an image thereon, and a transfer device for transferring the image from the image bearing member to a recording material at a transfer station. Wherein a limit value of electric power supplied to the transfer device is changed between a case where an imaged portion of the image bearing member is positioned at the transfer station and a case where a non-imaged portion of the image bearing member is positioned at the transfer station.
Inventors
- 👤 Nobuhiko Takekoshi
- 👤 Takashi Hasegawa
- 👤 Masahiro Inoue
- 👤 Yoichi Kimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 06:23
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/14; G03G15/16; G03G15/163; G03G15/1635; G03G15/1645; G03G15/01; G03G15/0105; G03G15/0131; G03G2215/00; G03G2215/16; G03G2215/1604; G03G2215/1642
Claims Analysis
Total Claims: 30
Claim 1
Independent Claim
159 words
An image forming apparatus comprising: an image bearing member for bearing an image thereon; and transfer means for transferring the image from said image bearing member to a recording material at a transfer station, said transfer means performing a plurality of image transferring operations for a common recording material; wherein a limit value of electric power supplied to said transfer means is changed between a case where an imaged portion of said image bearing member is positioned at said transfer station and a case where a non-imaged portion of said image bearing member is positioned at said transfer station, and wherein the limit value for said imaged portion and said non-imaged portion is set so that the limit value in a last image transferring operation is greater than the limit value in a first image transferring operation, and the limit value in a certain transferring operation does not become larger than the limit value in a next transferring operation.
Claim 2
Dependent Claim
159 words
An image forming apparatus comprising: an image bearing member for bearing an image thereon; and transfer means for transferring the image from said image bearing member to a recording material at a transfer station, said transfer means performing a plurality of image transferring operations for a common recording material; wherein a limit value of electric power supplied to said transfer means is changed between a case where an imaged portion of said image bearing member is positioned at said transfer station and a case where a non-imaged portion of said image bearing member is positioned at said transfer station, and wherein the limit value for said imaged portion and said non-imaged portion is set so that the limit value in a last image transferring operation is greater than the limit value in a first image transferring operation, and the limit value in a certain transferring operation does not become larger than the limit value in a next transferring operation.
Claim 3
Dependent Claim
35 words
An image forming apparatus according to claim 1, wherein said limit value regarding said imaged portion is equal to maximum voltage applied to said transfer means when said transfer means is controlled under constant current.
Claim 4
Dependent Claim
45 words
An image forming apparatus according to claim 1, further comprising a recording material bearing means for bearing the recording material, wherein the image is transferred from said image bearing member to the recording material born on said recording material bearing means at said transfer station.
Claim 5
Dependent Claim
50 words
An image forming apparatus according to claim 3, wherein said recording material bearing means comprises a recording material bearing sheet for bearing the recording material, and a support supporting said recording material bearing sheet and extending in a direction perpendicular to a shifting direction of said recording material bearing means.
Claim 6
Dependent Claim
25 words
An image forming apparatus according to claim 3, wherein said transfer means can be contacted with an inner side of said recording material bearing means.
Claim 7
Dependent Claim
27 words
An image forming apparatus according to claim 1, wherein said limit value of said non-imaged portion is set to be smaller than that of said image portion.
Claim 8
Dependent Claim
30 words
An image forming apparatus according to claim 1, wherein said limit value of at least one of said imaged and non-imaged portions is controlled in accordance with an environmental condition.
Claim 9
Dependent Claim
22 words
An image forming apparatus according to claim 1, wherein the image forming apparatus can form a full-color image on the recording material.
Claim 10
Dependent Claim
91 words
An image forming apparatus comprising: an image bearing member for bearing an image thereon; and transfer means for transferring the image from said image bearing member to a recording material at a transfer station, said transfer means performing a plurality of image transferring operations for a common recording material; wherein an amount of current applied to said transfer means is controlled under a constant current, and a maximum voltage value applied to said transfer means is set for every image transferring operation corresponding to the number of the image transferring operations.
Claim 11
Dependent Claim
91 words
An image forming apparatus comprising: an image bearing member for bearing an image thereon; and transfer means for transferring the image from said image bearing member to a recording material at a transfer station, said transfer means performing a plurality of image transferring operations for a common recording material; wherein an amount of current applied to said transfer means is controlled under a constant current, and a maximum voltage value applied to said transfer means is set for every image transferring operation corresponding to the number of the image transferring operations.
Claim 12
Dependent Claim
39 words
An image forming apparatus according to claim 9, wherein when a voltage smaller than the maximum voltage value is applied to said transfer means, the amount of current applied to said transfer means is controlled under the constant current.
Claim 13
Dependent Claim
71 words
An image forming apparatus according to claim 9, wherein said maximum voltage value is set so that the maximum voltage value in a last image transfer operation among said plurality of image transferring operations is greater than the maximum voltage value in a first image transferring operation and the maximum voltage value in a certain transferring operation does not become smaller than the maximum voltage value in a next transferring operation.
Claim 14
Dependent Claim
47 words
An image forming apparatus according to claim 9 or 11, further comprising a recording material bearing means for bearing the recording material, wherein the image is transferred from said image bearing member to the recording material born on said recording material bearing means at said transfer station.
Claim 15
Dependent Claim
49 words
An image forming apparatus according to claim 12, wherein said recording material bearing means comprises a recording material bearing sheet for bearing the recording material, and a support supporting said recording material-bearing sheet and extending in a direction perpendicular to a shifting direction of said recording material bearing means.
Claim 16
Dependent Claim
21 words
An image forming apparatus according to claim 9, wherein said maximum voltage value is controlled in accordance with an environmental condition.
Claim 17
Dependent Claim
25 words
An image forming apparatus according to claim 9, wherein said transfer means can be contacted with an inner side of said recording material bearing means.
Claim 18
Dependent Claim
22 words
An image forming apparatus according to claim 9, wherein the image forming apparatus can form a full-color image on the recording material.
Claim 19
Dependent Claim
92 words
An image forming apparatus comprising: an image bearing member for bearing an image thereon; and transfer means for transferring the image from said image bearing member to a recording material at a transfer station; wherein an amount of current applied to said transfer means is controlled under a constant current, and a maximum voltage value applicable to said transfer means is set smaller when a non-imaged portion of said image bearing member is in the transfer position than when an imaged portion of said image bearing member is in the transfer position.
Claim 20
Dependent Claim
92 words
An image forming apparatus comprising: an image bearing member for bearing an image thereon; and transfer means for transferring the image from said image bearing member to a recording material at a transfer station; wherein an amount of current applied to said transfer means is controlled under a constant current, and a maximum voltage value applicable to said transfer means is set smaller when a non-imaged portion of said image bearing member is in the transfer position than when an imaged portion of said image bearing member is in the transfer position.
Claim 21
Dependent Claim
38 words
An image forming apparatus according to claim 17, wherein the amount of current applied to said transfer means is controlled under the constant current when the voltage smaller than the maximum voltage is applied to said transfer means.
Claim 22
Dependent Claim
85 words
An image forming apparatus according to claim 17, wherein said transfer means performs a plurality of image transferring operations for a common recording material, and the maximum voltage value for said imaged portion is set so that the maximum voltage value in a last image transferring operation is greater than the maximum voltage value in a first image transferring operation, and the maximum voltage value in a certain transferring operation does not become smaller than the maximum voltage value in a last image transferring operation.
Claim 23
Dependent Claim
47 words
An image forming apparatus according to claim 17 or 19, further comprising a recording material bearing means for bearing the recording material, wherein the image is transferred from said image bearing member to the recording material born on said recording material bearing means at said transfer station.
Claim 24
Dependent Claim
52 words
An image forming apparatus according to claim 20, wherein said recording material bearing means comprises a recording material bearing sheet for bearing the recording material, and a supporting member for supporting said recording material bearing sheet and extending in a direction perpendicular to a shifting direction of said recording material bearing means.
Claim 25
Dependent Claim
25 words
An image forming apparatus according to claim 20, wherein said transfer means can be contacted with an inner side of said recording material bearing means.
Claim 26
Dependent Claim
68 words
An image forming apparatus according to claim 19, wherein the maximum voltage value of said non-imaged portion is so set that the maximum voltage value in the last image transferring operation is greater than the maximum voltage value in the first image transferring operation, and the maximum voltage value in a certain transferring operation does not become smaller than the maximum voltage value in a next transferring operation.
Claim 27
Dependent Claim
22 words
An image forming apparatus according to claim 19, wherein the image forming apparatus can form a full-color image on the recording material.
Claim 28
Dependent Claim
31 words
An image forming apparatus according to claim 17, wherein the maximum voltage value of at least one of said imaged and non-imaged portions is controlled in accordance with an environmental condition.
Claim 29
Dependent Claim
85 words
An image forming apparatus comprising: an image bearing member for bearing an image thereon; and transfer means for transferring the image from said image bearing member to a recording material at a transfer station, said transfer means being controlled under a constant voltage; wherein a maximum current value applicable to said transfer means is set smaller when a non-imaged portion of said image bearing member is in the transfer station than when an imaged portion of said image bearing member is in the transfer station.
Claim 30
Dependent Claim
85 words
An image forming apparatus comprising: an image bearing member for bearing an image thereon; and transfer means for transferring the image from said image bearing member to a recording material at a transfer station, said transfer means being controlled under a constant voltage; wherein a maximum current value applicable to said transfer means is set smaller when a non-imaged portion of said image bearing member is in the transfer station than when an imaged portion of said image bearing member is in the transfer station.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-02-04 | 2000-08-05 | 2001-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-02-04 | 2004-08-05 | 2005-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-02-04 | 2008-08-05 | 2009-02-04 | $7700.00 | Window Closed / Lapsed |