Patent US4725521A successfully refreshed from Google Patents.
US4725521A
Expired / Lapsed
US
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Carrier for developing electrostatic image
Assignee: Konica Minolta Inc
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Filing: 1986-09-23
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Granted: 1988-02-16
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Expires: 2006-09-23
Abstract
Abstract A carrier for developing electrostatic images is disclosed. The carrier comprises a core and a resin coating layer provided thereon. The coating layer comprises two kinds of polymer resin, one of them is a vinylidene fluoride/tetrafluoroethylene copolymer, and the other one is a polymer containing, as a monomer component, an acrylate which has a group substituted with at least one fluorine atom. The carrier is improved in its durability and electrostatic properties. A high density images without fog are obtained when electrophotographic images are developed with the developer containing this carrier.
Inventors
- 👤 Kunio Shigeta
- 👤 Jiro Takahashi
- 👤 Kenzi Tsuzita
- 👤 Hiroyuki Nomori
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:15
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/113; G03G9/1132; G03G9/1133; G03G9/1134
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
53 words
An electrostatic image developer having a toner and carrier, the carrier having a coating layer comprising a co-polymer of vinylidene fluoride/tetrafluoroethylene and a polymer containing, as a monomer component, an acrylate which has a group substitued with at least one fluorine atom as a side chain, said coatitng layer being from 0.05-20 μm.
Claim 2
Dependent Claim
53 words
An electrostatic image developer having a toner and carrier, the carrier having a coating layer comprising a co-polymer of vinylidene fluoride/tetrafluoroethylene and a polymer containing, as a monomer component, an acrylate which has a group substitued with at least one fluorine atom as a side chain, said coatitng layer being from 0.05-20 μm.
Claim 3
Dependent Claim
26 words
The developer of claim 1, wherein the molar ratio of vinylidene fluoride and tetrafluoroethylene in said co-polymer is within the range of from 75:25 to 95:5.
Claim 4
Dependent Claim
57 words
The developer of claim 1, wherein said acrylate having a group substituted with at least one fluorine atom as a side chain is represented by the general formula (1). ##STR5## wherein R represents a hydrogen atom or a methyl group, Rf represents an alkyl group or an aralkyl group substituted with at least one fluorine atom, respectively.
Claim 5
Dependent Claim
44 words
The developer of claim 1, wherein said coating layer comprises said vinylidene fluoride/tetrafluoroethylene co-polymer in an amount of from 50 to 95% by weight of said coating layer and said polymer containing said acrylate in an amount of from 50 to 5% by weight.
Claim 6
Dependent Claim
44 words
The developer of claim 1, wherein said coating layer comprises said vinylidene fluoride/tetrafluoroethylene co-polymer in an amount of from 70 to 95% by weight of said coating layer and said polymer containing said acrylate in an amount of from 30 to 5% by weight.
References Cited (Backward Citations)
US4297427A
Cited
US4272184A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-15 | 1991-08-17 | 1992-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-15 | 1995-08-17 | 1996-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-15 | 1999-08-17 | 2000-02-16 | $7700.00 | Window Closed / Lapsed |