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US4908290A
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US
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Toner for developing latent electrostatic images
Assignee: Ricoh Co Ltd
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Filing: 1987-11-13
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Granted: 1990-03-13
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Expires: 2007-11-13
Abstract
Abstract A toner for developing latent electrostatic images is disclosed, which comprises a colorant, and a binder agent comprising (i) polyester resin or epoxy resin, and (ii) styrene - methyl acrylate copolymer.
Inventors
- 👤 Yoichiro Watanabe
- 👤 Mitsuo Aoki
- 👤 Tetsuo Isoda
- 👤 Nobuhiro Nakayama
- 👤 Fumihiro Sasaki
- 👤 Karumi Kakigawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 03:20
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/087; G03G9/08742; G03G9/08753; G03G9/08702; G03G9/08706; G03G9/08708; G03G9/08711; G03G9/08755
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
102 words
A toner for developing latent electrostatic images comprising a colorant, and a binder agent which comprises (i) polyester resin having a weight average molecular weight of 8,000 to 16,000, and a glass transition temperature (Tg) of 50° C. to 65° C., or epoxy resin having a weight average molecular weight of 2,000 to 12,000, and a glass transition temperature (Tg) of 50° C. to 65° C., and (ii) styrene - methyl acrylate copolymer having a weight average molecular weight of 200,000 to 500,000, a gel content of 15 to 50%, and a glass transition temperature (Tg) of 55° C. to 70° C.
Claim 2
Dependent Claim
102 words
A toner for developing latent electrostatic images comprising a colorant, and a binder agent which comprises (i) polyester resin having a weight average molecular weight of 8,000 to 16,000, and a glass transition temperature (Tg) of 50° C. to 65° C., or epoxy resin having a weight average molecular weight of 2,000 to 12,000, and a glass transition temperature (Tg) of 50° C. to 65° C., and (ii) styrene - methyl acrylate copolymer having a weight average molecular weight of 200,000 to 500,000, a gel content of 15 to 50%, and a glass transition temperature (Tg) of 55° C. to 70° C.
Claim 3
Dependent Claim
43 words
The toner as claimed in claim 1, wherein the component (i) of said binder agent consists of said polyester resin and the content of said polyester resin in said biinder agent is in the range of 20 wt. % to 45 wt. %.
Claim 4
Dependent Claim
43 words
The toner as claimed in claim 1, wherein the component (i) of said binder resin consists of said epoxy resin and the content of said epoxy resin in said binder agent is in the range of 20. wt. % to 45 wt. %.
Claim 5
Dependent Claim
32 words
The toner as claimed in claim 1, further comprising a thermoplastic resin different from (i) and (ii) and present in an amount of 20 wt. % or less in said binder agent.
Claim 6
Dependent Claim
12 words
The toner as claimed in claim 1, further comprising a magnetic material.
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) | 1993-03-12 | 1993-09-11 | 1994-03-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-12 | 1997-09-11 | 1998-03-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-12 | 2001-09-11 | 2002-03-13 | $7700.00 | Window Closed / Lapsed |