US4804609A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Developing agent for electrophotography with silica and magnetite additives
Assignee: Sharp Corp
•
Filing: 1987-04-29
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Granted: 1989-02-14
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Expires: 2007-04-29
Abstract
Abstract A developing agent for electrophotographic copier contains SiO 2 and/or magnetite in addition to a toner such that talc can be effectively removed from the photoreceptor surface.
Inventors
- 👤 Yoshiaki Imanaka
- 👤 Hideaki Taniguchi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 00:46
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/097; G03G9/09708; G03G9/09725; G03G13/00; G03G13/06; G03G13/08; G03G9/083; G03G9/0831; G03G9/0833; G03G9/0837; G03G9/0838
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
102 words
In a developing agent for electrophotographic copier comprising toner, the improvement wherein said developing agent includes SiO 2 and magnetite externally added to said toner, the amount of SiO 2 in said developing agent is 0.05-0.50 wt % with respect to said toner, the amount of said magnetite in said developing agent is 0.05-0.50 wt % with respect to said toner, and the total amount of SiO 2 and magnetite in said developing agent is at least 0.3 wt % up to about 1.0 wt % with respect to said toner wherein said magnetite is of average particle diameter of about 0.50.
Claim 2
Dependent Claim
102 words
In a developing agent for electrophotographic copier comprising toner, the improvement wherein said developing agent includes SiO 2 and magnetite externally added to said toner, the amount of SiO 2 in said developing agent is 0.05-0.50 wt % with respect to said toner, the amount of said magnetite in said developing agent is 0.05-0.50 wt % with respect to said toner, and the total amount of SiO 2 and magnetite in said developing agent is at least 0.3 wt % up to about 1.0 wt % with respect to said toner wherein said magnetite is of average particle diameter of about 0.50.
Claim 3
Dependent Claim
26 words
The developing agent of claim 1 wherein said developing agent contains SiO 2 in the form of hydrophobic silica of particle size of about 10-50 mμ.
Claim 4
Dependent Claim
28 words
The developing agent of claim 1 wherein said developing agent contains magnetite in the form of cubic magnetic oxide of iron of average particle diameter about 0.50 μ.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-02-14 | 1992-08-15 | 1993-02-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-02-14 | 1996-08-15 | 1997-02-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-02-14 | 2000-08-15 | 2001-02-14 | $7700.00 | Window Closed / Lapsed |