US5118587A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic particles used for electrostatic latent image developer and process for producing the same
Assignee: Toda Kogyo Corp
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Filing: 1990-07-18
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Granted: 1992-06-02
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Expires: 2010-07-18
Abstract
Abstract Disclosed herein are magnetic particles used for an electrostatic latent image developer comprising composite particles containing from more than 80% by weight to not more than 99% by weight of fine ferromagnetic particles and a cured phenol resin, and having a number-average particle diameter of from not less than 1 μm to less than 10 μm and an apparent density of not greater than 1.5 g/cm 3 .
Inventors
- 👤 Shigeru Takaragi
- 👤 Toshiyuki Hakata
- 👤 Kazuo Fujioka
- 👤 Tetsuro Toda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 06:58
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/083; G03G9/0839; G03G9/0836; G03G9/0838; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/104
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
79 words
Magnetic particles suitable for use as an electrostatic latent image developer, said magnetic particles comprising composite particles containing from more than 80% by weight to not more than 99% by weight of fine ferromagnetic particles and a cured phenol resin, and having a number-average particle diameter of from not less than 1 μm to less than 10 μm, an apparent density of not greater than 1.5 g/cm 3 and a volumic electric resistivity of less than 10 12 ohm.cm.
Claim 2
Dependent Claim
79 words
Magnetic particles suitable for use as an electrostatic latent image developer, said magnetic particles comprising composite particles containing from more than 80% by weight to not more than 99% by weight of fine ferromagnetic particles and a cured phenol resin, and having a number-average particle diameter of from not less than 1 μm to less than 10 μm, an apparent density of not greater than 1.5 g/cm 3 and a volumic electric resistivity of less than 10 12 ohm.cm.
Claim 3
Dependent Claim
25 words
Magnetic particle according to claim 1, wherein said fine ferromagnetic particles are fine ferro magnetic particles subjected at the surface thereof to a hydrophobic treatment.
Claim 4
Dependent Claim
20 words
Magnetic particles according to claim 2, wherein a fluidizing rate of the composite particles is not less than 0.45 g/sec.
Claim 5
Dependent Claim
23 words
Magnetic particles according to claim 3, wherein a hydrophobic degree of said fine ferromagnetic particles treated is from 20 to 60% by weight.
References Cited (Backward Citations)
US3533835A
Cited
US3960805A
Cited
US4788236A
Cited
US4543312A
Cited
JPS6151019A
Cited
US4640971A
Cited
JPS6227455A
Cited
US4839445A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-06-02 | 1995-12-02 | 1996-06-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-06-02 | 1999-12-02 | 2000-06-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-06-02 | 2003-12-02 | 2004-06-02 | $7700.00 | Window Closed / Lapsed |