US4071655A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Treated ferromagnetic carrier particles for development powders
Assignee: Pitney Bowes Inc
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Filing: 1976-12-20
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Granted: 1978-01-31
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Expires: 1996-12-20
Abstract
Abstract Carrier particles of development powders are treated with a sodium salt of polystyrene sulfonic acid. As a result of the treatment, the triboelectric properties of the carrier particles are better controlled.
Inventors
- 👤 George Brana
- 👤 Bheema Rao Vijayendran
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:40
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/113; G03G9/1132; G03G9/1133; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2998
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
65 words
A ferromagnetic carrier particle for use in electrophotographic development of latent images capable of inducing an electrostatic charge in a toner mixed therewith the surface of which has been treated with a sodium salt of polystyrene sulfonic acid having a minimum molecular weight of 50,000, said treated particle having a charge to mass ratio of 24 × 10 -6 to 36 × 10 -6 coul/gm.
Claim 2
Dependent Claim
65 words
A ferromagnetic carrier particle for use in electrophotographic development of latent images capable of inducing an electrostatic charge in a toner mixed therewith the surface of which has been treated with a sodium salt of polystyrene sulfonic acid having a minimum molecular weight of 50,000, said treated particle having a charge to mass ratio of 24 × 10 -6 to 36 × 10 -6 coul/gm.
Claim 3
Dependent Claim
20 words
The carrier particle of claim 1 wherein said member is iron having a particle size of 50 to 400 microns.
Claim 4
Dependent Claim
116 words
In a method of treating ferromagnetic carrier particles for development powders, the combination comprising: A. adding a quantity of the sodium salts of polystyrene sulfonic acid to a solvent to produce a 10-80% solution of said sulfonic acid salt to solvent; B. adding a second acid to said solution to obtain a pH of 2.0 to 2.5; C. placing the carrier particles having a particle size of 50 to 400 microns into the solution in the proportion of up to 500 grams of particles per 100 cc of solution to form a mixture; D. rolling the mixture; E. decanting the excess solution from the mixture; F. washing the carrier particles; and G. drying the carrier particles.
Claim 5
Dependent Claim
116 words
In a method of treating ferromagnetic carrier particles for development powders, the combination comprising: A. adding a quantity of the sodium salts of polystyrene sulfonic acid to a solvent to produce a 10-80% solution of said sulfonic acid salt to solvent; B. adding a second acid to said solution to obtain a pH of 2.0 to 2.5; C. placing the carrier particles having a particle size of 50 to 400 microns into the solution in the proportion of up to 500 grams of particles per 100 cc of solution to form a mixture; D. rolling the mixture; E. decanting the excess solution from the mixture; F. washing the carrier particles; and G. drying the carrier particles.
Claim 6
Dependent Claim
18 words
The method of claim 3 wherein the carrier particles are washed with alcohol after decanting the excess solution.
Claim 7
Dependent Claim
15 words
The method of claim 4 including the step of adding hydrazine sulfate to the alcohol.
Claim 8
Dependent Claim
10 words
The method of claim 4 wherein said solvent is water.
Claim 9
Dependent Claim
10 words
The method of claim 4 wherein said solvent is alcohol.
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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) | 1981-01-30 | 1981-08-01 | 1982-01-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-01-30 | 1985-08-01 | 1986-01-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-01-30 | 1989-08-01 | 1990-01-31 | $7700.00 | Window Closed / Lapsed |