US4518673A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrophotographic developer
Assignee: Proterial Ltd
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Filing: 1983-04-26
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Granted: 1985-05-21
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Expires: 2003-04-26
Abstract
Abstract In a developer containing as toner at least a resin component and a coloring agent, when (A) a styrene-acrylic copolymer and (B) a polyester resin is used as the resin component and making the toner to have an electric resistance of 10 13 Ω.cm or higher and a triboelectrification quantity of an absolute value of 5 μC/g or more, the resulting developer shows no offset phenomenon and gives excellent image quantity, transfer efficiency and good productivity.
Inventors
- 👤 Koji Noguchi
- 👤 Masumi Asanae
- 👤 Fumio Kimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 01:52
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/0821; G03G9/0823; G03G9/087; G03G9/08702; G03G9/08706; G03G9/08708; G03G9/08711; G03G9/08742; G03G9/08755
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
71 words
A transferable electrophotographic developer which includes a toner comprising a resin component and a coloring agent wherein (1) said resin component includes (A) 10 to 80% by weight of a styrene-acrylic copolymer and (B) 10 to 80% by weight of a polyester resin, and (2) said toner has an electric resistance of 10 13 Ω·cm or higher and a triboelectrification quantity of 5 μC/g or less or +5 μC/g or more.
Claim 2
Dependent Claim
71 words
A transferable electrophotographic developer which includes a toner comprising a resin component and a coloring agent wherein (1) said resin component includes (A) 10 to 80% by weight of a styrene-acrylic copolymer and (B) 10 to 80% by weight of a polyester resin, and (2) said toner has an electric resistance of 10 13 Ω·cm or higher and a triboelectrification quantity of 5 μC/g or less or +5 μC/g or more.
Claim 3
Dependent Claim
16 words
A developer according to claim 1, wherein said resin component further includes (C) a styrene-butadiene copolymer.
Claim 4
Dependent Claim
27 words
A developer according to claim 1, wherein said resin component further includes an aliphatic resin as a releasing agent in an amount ranging from 1-20% by weight.
Claim 5
Dependent Claim
16 words
A developer according to claim 1, which further comprises a magnetic powder to give toner particles.
Claim 6
Dependent Claim
16 words
A developer according to claim 1, wherein the weight ratio of (A)/(B) is 1/9 to 9/1.
Claim 7
Dependent Claim
31 words
A developer according claim 2, wherein the proportion of (A) is 10 to 80% by weight, (B) is 10 to 80% by weight and (C) is 10 to 80% by weight.
Claim 8
Dependent Claim
18 words
A developer according to claim 4, wherein the content of magnetic powder is 40 to 80% by weight.
Claim 9
Dependent Claim
25 words
A developer according to claim 1, wherein the styrene-acrylic copolymer (A) is a copolymer of styrene and acrylate or a copolymer of styrene and methacrylate.
Claim 10
Dependent Claim
18 words
A developer according to claim 1, wherein the polyester resin (B) is a polyester resin obtained from bisphenol.
Claim 11
Dependent Claim
33 words
A developer according to claim 2, wherein said (C) styrene-butadiene component is present in an amount ranging from 25% or less by weight based on the total weight of (A), (B), and (C).
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-05-20 | 1988-11-19 | 1989-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-05-20 | 1992-11-19 | 1993-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-05-20 | 1996-11-19 | 1997-05-21 | $7700.00 | Window Closed / Lapsed |