Patent US5557384A successfully refreshed from Google Patents.
US5557384A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Image transferring device for image forming equipment
Assignee: Ricoh Co Ltd
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Filing: 1994-10-19
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Granted: 1996-09-17
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Expires: 2014-10-19
Abstract
Abstract An image transferring device incorporated in an image forming apparatus and capable of surely preventing a sheet from wrapping around a photoconductive element and from being incompletely separated from a transfer belt. A transfer bias and discharge are effected to prevent changes in the resistances of the transfer belt and sheet ascribable to changes in environment front translating into changes in a current to flow to the photoconductive element, and to efficiently dissipate a charge deposited on the belt. Various members constituting the device are positioned relative to one another such that the discharging effect is achievable most effectively while preventing the transfer bias from causing dielectric breakdown in any constituent part. A bias roller is held in contact with the transfer belt which is made of a dielectric material. A current I OUT to flow frown the bias roller to ground via a nip portion between the belt and an image carrier and the image carrier is maintained greater than or equal to a current I 2 to flow from the contact electrode to ground via the belt without the intermediary of the nip portion.
Inventors
- 👤 Satoshi Takano
- 👤 Itaru Matsuda
- 👤 Yuko Harasawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 07:43
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/14; G03G15/16; G03G15/1665; G03G15/167; G03G15/1675; G03G15/1605; G03G15/1685; G03G2215/00; G03G2215/16; G03G2215/1604; G03G2215/1623; G03G2215/1647; G03G2215/1661
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
129 words
A device for transferring an image formed on an image carrier to a sheet and then separating said sheet from said image carrier, said device comprising: a transfer belt movable into contact with an outer periphery of the image carrier; drive means for causing said transfer belt to rotate; a contact electrode held in direct contact with said transfer belt; and charge applying means for applying a charge to said transfer belt via said contact electrode; wherein a current flow I OUT from said contact electrode to ground via a nip portion between said transfer belt and said image carrier is maintained greater than or equal to a current flow I 2 from said contact electrode to ground via said transfer belt without the intermediary of said nip portion.
Claim 2
Independent Claim
129 words
A device for transferring an image formed on an image carrier to a sheet and then separating said sheet from said image carrier, said device comprising: a transfer belt movable into contact with an outer periphery of the image carrier; drive means for causing said transfer belt to rotate; a contact electrode held in direct contact with said transfer belt; and charge applying means for applying a charge to said transfer belt via said contact electrode; wherein a current flow I OUT from said contact electrode to ground via a nip portion between said transfer belt and said image carrier is maintained greater than or equal to a current flow I 2 from said contact electrode to ground via said transfer belt without the intermediary of said nip portion.
Claim 3
Dependent Claim
19 words
A device as claimed in claim 1, further comprising current control means for maintaining said current I OUT constant.
Claim 4
Dependent Claim
49 words
A device as claimed in claim 1, wherein assuming that a linear velocity of said transfer belt and a length of said contact electrode are respectively P (cm/sec) and d(cm), said current I OUT is so selected as to satisfy a relation 2/10 8 ≦I OUT /(P·d)≦8/10 8 .
Claim 5
Dependent Claim
66 words
A device as claimed in claim 1, wherein said transfer belt includes a front surface which carries a sheet, said transfer belt further including a rear surface, and wherein said contact electrode contacts the rear surface of said transfer belt and said contact electrode is disposed at a location such that said current I OUT is greater than or equal to said current I 2 .
Claim 6
Dependent Claim
33 words
A device as claimed in claim 1, the dielectric material constituting said transfer belt has a resistance which renders said current I OUT greater than or equal to said current I 2 .
Claim 7
Dependent Claim
42 words
A device as claimed in claim 1, further including discharge means, said discharge means including at least one discharge member disposed downstream of said contact electrode, wherein said discharge means is connected to ground, and I 2 flows through said discharge means.
Claim 8
Dependent Claim
28 words
A device as claimed in claim 7, wherein said at least one discharge member is between said contact electrode and a support roller downstream of the nip portion.
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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) | 1999-09-17 | 2000-03-18 | 2000-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-09-17 | 2004-03-18 | 2004-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-09-17 | 2008-03-18 | 2008-09-17 | $7700.00 | Window Closed / Lapsed |