Patent US4246331A successfully refreshed from Google Patents.
US4246331A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrophotographic developers containing sublaminate dyes
Assignee: SUBLIGRAPHICS SA A CORP OF SWIZTERLAND
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Filing: 1979-03-05
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Granted: 1981-01-20
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Expires: 1999-03-05
Abstract
Abstract An electrophotographic developer is composed of particles comprising magnetic cores which are coated with an organic substance and at least one dyestuff which passes into the vapour state at a temperature in the range of from 100° to 220° C. at atmospheric pressure.
Inventors
- 👤 Wolfgang Mehl
- 👤 Dieter Hendriks
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 00:52
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/09; G03G9/0926; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/104
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
102 words
An electrophotographic developer, suitable for magnetic brush development, composed solely of particles comprising magnetic cores consisting of a ferromagnetic substance and representing at least 50% PG,15 of the weight of the developer particles, coated with an organic binder, devoid of wax and containing more than 10% of at least one dyestuff, which dyestuff passes into the vapour state at a temperature in the range of from 100° to 220° C. at atmospheric pressure and is a monoazo, anthraquinone, quinophthalone or styryl dyestuff, and wherein the particles are spherical or spherlike shaped and have an average diameter of from 1 to 30 microns.
Claim 2
Dependent Claim
102 words
An electrophotographic developer, suitable for magnetic brush development, composed solely of particles comprising magnetic cores consisting of a ferromagnetic substance and representing at least 50% PG,15 of the weight of the developer particles, coated with an organic binder, devoid of wax and containing more than 10% of at least one dyestuff, which dyestuff passes into the vapour state at a temperature in the range of from 100° to 220° C. at atmospheric pressure and is a monoazo, anthraquinone, quinophthalone or styryl dyestuff, and wherein the particles are spherical or spherlike shaped and have an average diameter of from 1 to 30 microns.
Claim 3
Dependent Claim
13 words
A developer as in claim 1, wherein the organic binder is a polymer.
Claim 4
Dependent Claim
20 words
A developer as in claim 2, wherein the polymer represents 10 and 40% of the weight of the developer particles.
Claim 5
Dependent Claim
23 words
A developer as in claim 2, wherein the magnetic cores are coated with a synthetic polymer which does not fuse below 150° C.
Claim 6
Dependent Claim
13 words
A developer as claim 2 wherein the coating polymer is a polyamide resin.
Claim 7
Dependent Claim
28 words
A developer as in claim 2, wherein the coating polymer is a member selected from the group consisting of an epoxy resin, a cellulose ether or butadiene copolymer.
Claim 8
Dependent Claim
17 words
A developer as in claim 3 wherein the polymer also contains up to 10% of carbon black.
Claim 9
Dependent Claim
14 words
A developer as in claim 2 wherein the sublimable dyestuff is a monoazo dyestuff.
Claim 10
Dependent Claim
22 words
A developer as in claim 2 wherein the polymer coating the magnetic cores has a thickness of form 2 to 10 microns.
Claim 11
Dependent Claim
24 words
A developer as in claim 2, wherein the coated ferromagnetic cores are in the form of small spheres of diameter 1 to 10 microns.
Claim 12
Dependent Claim
14 words
A developer as in claim 2 wherein the polymer coating contains an anti-static agent.
Claim 13
Dependent Claim
17 words
A developer as in claim 6 wherein the polymer coating contains a very fine silicon oxide powder.
Claim 14
Dependent Claim
17 words
An electrophotographic developer as in claim 2 wherein the polymer coating contains 10-50% of a sublimable dyestuff.
Claim 15
Dependent Claim
29 words
An electrophotographic developer as in claim 2 wherein the polymer coating contains a member selected from the group consisting of 1-amino-2-methoxy- or phenoxy-4-hydroxy anthraquinone, 1-amino-2,B-methoxyethoxy-4-hydroxy-anthraquinone, a hydroxyquinophthalone and 1,4-dihydroxy-5-amino-8-isopropylaminoanthraquinone.
Claim 16
Dependent Claim
19 words
A developer as in claim 1 wherein the sublimable dyestuff possesses at least two substituents different from one another.
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) | 1984-01-20 | 1984-07-21 | 1985-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-20 | 1988-07-21 | 1989-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-20 | 1992-07-21 | 1993-01-20 | $7700.00 | Window Closed / Lapsed |