Patent US4629673A successfully refreshed from Google Patents.
US4629673A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Resin-coated carrier for use in two-component electrophotographic developers
Assignee: Toshiba Corp
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Filing: 1985-06-04
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Granted: 1986-12-16
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Expires: 2005-06-04
Abstract
Abstract A carrier for use as a component in electrophotographic two-component developers having improved mechanical strength, durability and triboelectric charge characteristics comprising porous magnetite particles coated with a cross linked polymeric film comprising an epoxy resin and a polyamide resin. A two-component electrophotographic developer comprising resin coated porous magnetite carrier particles and toner particles and a method of producing resin coated porous magnetite carrier particles are also disclosed.
Inventors
- 👤 Shigenobu Osawa
- 👤 Tamotsu Murakami
- 👤 Takashi Mizuma
- 👤 Katsuhide Sano
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 21:56
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/113; G03G9/1132; G03G9/1135; G03G9/1137
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
51 words
A carrier for use in a two-component electrophotographic developer which comprises a core particle comprising porous magnetite coated with a resin film, said core particle being the reaction product of a process which includes the step of burning iron oxide at a temperature of from about 700° to about 800° C.
Claim 2
Dependent Claim
51 words
A carrier for use in a two-component electrophotographic developer which comprises a core particle comprising porous magnetite coated with a resin film, said core particle being the reaction product of a process which includes the step of burning iron oxide at a temperature of from about 700° to about 800° C.
Claim 3
Dependent Claim
14 words
A carrier as claimed in claim 1, wherein iron oxide is red iron oxide.
Claim 4
Dependent Claim
17 words
A carrier as claimed in claim 1, wherein said resin film is a cross linked polymeric film.
Claim 5
Dependent Claim
20 words
A carrier as claimed in claim 3, wherein said cross linked film comprises an epoxy resin and a polyamide resin.
Claim 6
Dependent Claim
25 words
A carrier as claimed in claim 1, wherein the proportion of said resin film is about 0.5 to 6% by weight of said core particle.
Claim 7
Dependent Claim
66 words
A two-component electrophotographic developer comprising a mixture of: a carrier formed of porous magnetite core particles coated with a resin film, said core particle being the reaction product of a process which includes the step of burning iron oxide at a temperature of from about 700° to about 800° C.; and toner particles having a triboelectric charge property to be deposited on an electrostatic latent image.
Claim 8
Dependent Claim
66 words
A two-component electrophotographic developer comprising a mixture of: a carrier formed of porous magnetite core particles coated with a resin film, said core particle being the reaction product of a process which includes the step of burning iron oxide at a temperature of from about 700° to about 800° C.; and toner particles having a triboelectric charge property to be deposited on an electrostatic latent image.
Claim 9
Dependent Claim
22 words
A two-component electrophotographic developer as claimed in claim 6, wherein the toner density lies in the range from about 5% to 10%.
Claim 10
Dependent Claim
19 words
A two-component electrophotographic developer as claimed in claim 6, wherein said resin film is a cross linked polymeric film.
Claim 11
Dependent Claim
23 words
A two-component electrophotographic developer as claimed in claim 8, wherein said cross linked polymeric film comprises an epoxy resin and a polyamide resin.
Claim 12
Independent Claim
42 words
A method of preparing a carrier for use in a two-component electrophotographic developer comprising the steps of: (a) burning iron oxide particles at a temperature of from about 700° to about 800° C.; and (b) coating said particles with a resin film.
Claim 13
Independent Claim
42 words
A method of preparing a carrier for use in a two-component electrophotographic developer comprising the steps of: (a) burning iron oxide particles at a temperature of from about 700° to about 800° C.; and (b) coating said particles with a resin film.
Claim 14
Dependent Claim
19 words
A method as claimed in claim 10, wherein said resin film comprises an epoxy resin and a polyamide resin.
Claim 15
Dependent Claim
20 words
A method as claimed in claim 10, further comprising the step of cross linking the resin coating on said particles.
Claim 16
Dependent Claim
20 words
A method as claimed in claim 12, wherein said cross linking step is effected by heat-treating the resin coated particles.
Claim 17
Dependent Claim
14 words
A method according to claim 10, wherein said iron oxide is red iron oxide.
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) | 1989-12-15 | 1990-06-16 | 1990-12-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-15 | 1994-06-16 | 1994-12-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-15 | 1998-06-16 | 1998-12-16 | $7700.00 | Window Closed / Lapsed |