Patent US5150165A successfully refreshed from Google Patents.
US5150165A
Expired / Lapsed
US
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Image forming apparatus having image transfer member
Assignee: Canon Inc
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Filing: 1991-04-09
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Granted: 1992-09-22
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Expires: 2011-04-09
Abstract
Abstract An image forming apparatus having an image bearing member and an image transfer charger for transferring a toner image from the image bearing member onto a transfer material. The transfer charger has a transfer member contactable to the backside of the transfer material. The transfer member includes a conductive base, and a surface layer outside the eleastic layer. The transfer member's characteristics fall within the parameters of: 5×10.sup.7 ≦R.sub.2 ≦5×10.sup.10 (ohm.cm), and R.sub.1 d.sub.1 /R.sub.2 d.sub.2 ≧10 where r 1 is a volume resistivity of the elastic layer, d 1 is a thickness of the elastic layer, R 2 is a volume resistivity of the surface layer, and d 2 is a thickness of the surface layer.
Inventors
- 👤 Jun Asai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:11
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/14; G03G15/16; G03G15/1665; G03G15/167; G03G15/1685
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
156 words
An image forming apparatus comprising: an image bearing member; image transfer charging means for transferring a toner image from said image bearing member onto a transfer material, said transfer charging means having a transfer member contactable to a backside of the transfer material; wherein said transfer member includes a conductive base, an elastic layer outside said conductive base, and a surface layer outside said elastic layer, satisfying: 5×10.sup.7 ≦R.sub.2 ≦5×10.sup.10 (ohm.cm), and R.sub.1 d.sub.1 /R.sub.2 d.sub.2 ≧10 where R 1 is a volume resistivity of said elastic layer (ohm.cm); d 1 is a thickness thereof (cm); R 2 is a volume resistivity of said surface layer (ohm.cm); and d 2 is a thickness thereof; and wherein a resistance of said surface layer and a resistance of said elastic layer vary in accordance with a change in ambient condition and a resistance variation of said surface layer is larger than a resistance variation of said elastic layer.
Claim 2
Dependent Claim
156 words
An image forming apparatus comprising: an image bearing member; image transfer charging means for transferring a toner image from said image bearing member onto a transfer material, said transfer charging means having a transfer member contactable to a backside of the transfer material; wherein said transfer member includes a conductive base, an elastic layer outside said conductive base, and a surface layer outside said elastic layer, satisfying: 5×10.sup.7 ≦R.sub.2 ≦5×10.sup.10 (ohm.cm), and R.sub.1 d.sub.1 /R.sub.2 d.sub.2 ≧10 where R 1 is a volume resistivity of said elastic layer (ohm.cm); d 1 is a thickness thereof (cm); R 2 is a volume resistivity of said surface layer (ohm.cm); and d 2 is a thickness thereof; and wherein a resistance of said surface layer and a resistance of said elastic layer vary in accordance with a change in ambient condition and a resistance variation of said surface layer is larger than a resistance variation of said elastic layer.
Claim 3
Dependent Claim
14 words
An apparatus according to claim 1, wherein said elastic layer is of foamed material.
Claim 4
Dependent Claim
17 words
An apparatus according to claim 1, wherein said transfer member is contactable to said image bearing member.
Claim 5
Dependent Claim
21 words
An apparatus according to claim 1, wherein said transfer charging means includes means for applying a voltage to said transfer member.
Claim 6
Dependent Claim
43 words
An apparatus according to claim 4, wherein said voltage application means applies to said transfer member a voltage for transferring the toner from said transfer member to said image bearing member when the transfer material is not present at an image transfer position.
Claim 7
Dependent Claim
47 words
An apparatus according to claim 4 or 5, wherein said voltage applying means applies to the transfer member a voltage of the same polarity as the charging polarity of the toner on said image bearing member, when the transfer material is not present at the transfer position
Claim 8
Dependent Claim
19 words
An apparatus according to claim 1 or 3, wherein said transfer member is in the form of a roller.
Claim 9
Dependent Claim
14 words
An apparatus according to claim 1, wherein said surface layer is of resin material.
Claim 10
Dependent Claim
15 words
An apparatus according to claim 8, wherein said surface layer is of polyurethane resin material.
Claim 11
Dependent Claim
17 words
An apparatus according to claim 1, wherein the volume resistivity R 1 satisfies: 5×10.sup.10 ≦R.sub.1 ≦5×10.sup.13 (ohm.cm)
Claim 12
Dependent Claim
55 words
An apparatus according to claim 1, 2 or 10, wherein R L /R H ≦10, where R H is a resistance of said transfer member under high temperature (32.5° C.) and high humidity (90%relative humidity) condition; and R L is a resistance thereof under low temperature (15° C.) and low humidity (10% relative humidity) condition.
Claim 13
Independent Claim
21 words
An apparatus according to claims, 1, 2, 8, 9 or 10, wherein said elastic layer comprises EPDM as a major component.
Claim 14
Dependent Claim
50 words
An apparatus according to claim 1, wherein said surface layer exhibits a resistance variation larger than a resistance variation of said elastic layer, when the ambient condition changes from high temperature (32.5° C.) and high humidity (90% relative humidity) to low temperature (15° C.) and low humidity (10% relative humidity).
Claim 15
Dependent Claim
12 words
An apparatus according to claim 1, wherein d 2 <d 1 .
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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) | 1995-09-22 | 1996-03-23 | 1996-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-22 | 2000-03-23 | 2000-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-22 | 2004-03-23 | 2004-09-22 | $7700.00 | Window Closed / Lapsed |