US4933251A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrophotographic developer
Assignee: Fujifilm Business Innovation Corp
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Filing: 1988-08-04
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Granted: 1990-06-12
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Expires: 2008-08-04
Abstract
Abstract An electrophotographic developer is described, comprising toner particles and carrier particles, characterized in that the toner particles have a layer of externally additive agents comprising fine metal oxide particles having an electric resistance of 1×10 2 to 1×10 9 Ω·cm and fine silica particles and cleaning aid particles, and the layer of externally additive agents does not have a chain like structure.
Inventors
- 👤 Masanori Ichimura
- 👤 Toru Murakami
- 👤 Koichi Oyamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:56
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/097; G03G9/09708; G03G9/09725
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
56 words
An electrophotographic developer comprising toner particles and carrier particles, wherein the toner particle has on the surface thereof a layer of externally added agents comprising fine metal oxide particles having an electric resistance of 1×10 2 to 1×10 9 Ω·cm and fine silica particles, and the layer of externally added agents has a non-chain like structure.
Claim 2
Dependent Claim
56 words
An electrophotographic developer comprising toner particles and carrier particles, wherein the toner particle has on the surface thereof a layer of externally added agents comprising fine metal oxide particles having an electric resistance of 1×10 2 to 1×10 9 Ω·cm and fine silica particles, and the layer of externally added agents has a non-chain like structure.
Claim 3
Dependent Claim
20 words
The electrophotographic developer as claimed in claim 1 wherein said layer of externally added agents further includes cleaning aid particles.
Claim 4
Dependent Claim
65 words
The electrophotographic developer as claimed in claim 1, wherein the layer of externally added agents is formed by adding fine metal oxide particles having an electric resistance of 1×10 2 to 1×10 9 Ω·cm and fine silica particles to the toner particles, and then mixing said metal oxide, silica and toner particles in a Henschel mixer at a circumferential speed of a least 30 m/sec.
Claim 5
Dependent Claim
34 words
The electrophotographic developer as claimed in claim 1, wherein an amount of the fine metal oxide particles added is from 0.1 to 5.0 parts by weight per 100 parts by weight of the toner.
Claim 6
Dependent Claim
24 words
The electrophotographic developer as claimed in claim 1, wherein an average particle diameter of the fine metal oxide particles is 0.3 μm or less.
Claim 7
Dependent Claim
23 words
The electrophotographic developer as claimed in claim 1, wherein said toner particles have an average particle diameter of less than about 30 μm.
Claim 8
Dependent Claim
21 words
The electrophotographic developer as claimed in claim 1, wherein said carrier particles have an average particle diameter less than 500 μm.
References Cited (Backward Citations)
US4623604A
Cited
US4513074A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-06-11 | 1993-12-11 | 1994-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-06-11 | 1997-12-11 | 1998-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-06-11 | 2001-12-11 | 2002-06-12 | $7700.00 | Window Closed / Lapsed |