Patent US6026257A successfully refreshed from Google Patents.
US6026257A
Expired / Lapsed
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Image forming apparatus with constant current voltage control
Assignee: Canon Inc
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Filing: 1998-09-21
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Granted: 2000-02-15
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Expires: 2018-09-21
Abstract
Abstract An image forming apparatus includes an image bearing member; a transfer member for transferring an image from the image bearing member onto a transfer material by a nip formed between the image bearing member and the transfer member; control means for effecting a constant current control for the transfer member with a predetermined current when a non-image area of the image bearing member is at the nip, and for effecting a constant voltage control for the transfer member during image transfer operation on the basis of a voltage applied to the transfer member during the constant current control; wherein a higher one of a constant voltage control signal for controlling the voltage in the constant voltage control and a constant current control signal for controlling the current in the constant current control, is selected as an output signal to the transfer member.
Inventors
- 👤 Hiroshi Takami
- 👤 Tatsuto Tachibana
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:22
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/14; G03G15/16; G03G15/1665; G03G15/167; G03G15/1675
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
142 words
An image forming apparatus comprising: an image bearing member; a transfer member for transferring an image from said image bearing member onto a transfer material by a nip formed between said image bearing member and said transfer member; control means for effecting a constant current control for said transfer member with a predetermined current when a non-image area of said image bearing member is at said nip, and for effecting a constant voltage control for the transfer member during image transfer operation on the basis of a voltage applied to said transfer member during said constant current control; wherein a higher one of a constant voltage control signal for controlling the voltage in the constant voltage control and a constant current control signal for controlling the current in the constant current control, is selected as an output signal to said control means.
Claim 2
Dependent Claim
142 words
An image forming apparatus comprising: an image bearing member; a transfer member for transferring an image from said image bearing member onto a transfer material by a nip formed between said image bearing member and said transfer member; control means for effecting a constant current control for said transfer member with a predetermined current when a non-image area of said image bearing member is at said nip, and for effecting a constant voltage control for the transfer member during image transfer operation on the basis of a voltage applied to said transfer member during said constant current control; wherein a higher one of a constant voltage control signal for controlling the voltage in the constant voltage control and a constant current control signal for controlling the current in the constant current control, is selected as an output signal to said control means.
Claim 3
Dependent Claim
19 words
An apparatus according to claim 1, wherein the constant current control signal is on-state during the image transfer operation.
Claim 4
Dependent Claim
22 words
An apparatus according to claim 1, wherein said constant voltage control signal is on-state when the non-image area is at said nip.
Claim 5
Dependent Claim
45 words
An apparatus according to claim 1, wherein when the image transfer is continuously carried out, the constant current control is effected in a duration from passage of a leading edge of a transfer material to arrival of a leading edge of the next transfer material.
Claim 6
Dependent Claim
38 words
An apparatus according to claim 3, wherein when the non-image area of said image bearing member is at said nip, a level of said constant voltage control signal is lower than during image transfer onto the transfer material.
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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) | 2003-02-14 | 2003-08-16 | 2004-02-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-02-14 | 2007-08-16 | 2008-02-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-02-14 | 2011-08-16 | 2012-02-15 | $7700.00 | Window Closed / Lapsed |