US4407923A
Expired / Lapsed
US
⏱️ 0.0 years remaining
One component magnetic developer
Assignee: Kyocera Mita Industrial Co Ltd
•
Filing: 1982-06-24
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Granted: 1983-10-04
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Expires: 2002-06-24
Abstract
Abstract Disclosed is a dry magnetic developer consisting essentially of a particulate shaped article of a composition comprising a binder resin medium and a powdery magnetic material dispersed in the binder resin medium, wherein said composition comprises as the powdery magnetic material a non-pulverizing agglomerate having a secondary particle size of 1 to 10 microns, which is formed by granulating and sintering fine cubic particles of magnetite or other ferrite having a primary particle size of 0.1 to 1 micron.
Inventors
- 👤 Nobuhiro Miyakawa
- 👤 Masanori Fujii
- 👤 Kouzi Maekawa
- 👤 Haruo Koyama
- 👤 Takashi Teshima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 07:34
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/083; G03G9/0836; G03G9/0837; G03G9/0838; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/104
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
77 words
A dry magnetic developer consisting essentially of a particulate shaped article of a composition comprising a binder resin medium and a powdery magnetic material dispersed in the binder resin medium, wherein said composition comprises as the powdery magnetic material a non-pulverizing agglomerate having a secondary particle size of 1 to 10 microns, which is formed by granulating and sintering fine cubic particles of magnetite or other ferrite having a primary particle size of 0.1 to 1 micron.
Claim 2
Dependent Claim
77 words
A dry magnetic developer consisting essentially of a particulate shaped article of a composition comprising a binder resin medium and a powdery magnetic material dispersed in the binder resin medium, wherein said composition comprises as the powdery magnetic material a non-pulverizing agglomerate having a secondary particle size of 1 to 10 microns, which is formed by granulating and sintering fine cubic particles of magnetite or other ferrite having a primary particle size of 0.1 to 1 micron.
Claim 3
Dependent Claim
30 words
A magnetic developer as set forth in claim 1, wherein the agglomerate has an apparent density of 0.4 to 1.5 g/ml as measured according to the method of JIS K-5101.
Claim 4
Dependent Claim
28 words
A magnetic developer as set forth in claim 1, wherein the developer particles have surfaces comprising faces of the exposed non-agglomerate and faces of the binder resin medium.
Claim 5
Dependent Claim
36 words
A magnetic developer as set forth in claim 1, wherein the binder resin medium has a volume resistivity of at least 1×10 15 Ω-cm as measured in the state where the non-pulverizing agglomerate is not incorporated.
Claim 6
Dependent Claim
39 words
A magnetic developer as set forth in claim 1, wherein the non-pulverizing agglomerate is present in an amount of 40 to 70% by weight based on the total amount of the binder resin medium and the powdery magnetic material.
Claim 7
Dependent Claim
38 words
A magnetic developer as set forth in claim 1, wherein the magnetic developer has a number average particle size of 5 to 35 μm, which is at least two times the number average particle size of the agglomerate.
References Cited (Backward Citations)
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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) | 1986-10-03 | 1987-04-04 | 1987-10-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-10-03 | 1991-04-04 | 1991-10-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-10-03 | 1995-04-04 | 1995-10-04 | $7700.00 | Window Closed / Lapsed |