US4898801A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic carrier of developer for electrophotographic copying machines composed of ferrite and a selected metal oxide
Assignee: Nippon Iron Powder Co Ltd
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Filing: 1987-10-19
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Granted: 1990-02-06
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Expires: 2007-10-19
Abstract
Abstract A carrier of developers composed of a composition represented by (MO) X (Fe 2 O 3 ) having bulk density of 1.8-3.4 g/Cm 3 and magnetization of 10-30 emu/g in a magnetic field of 450-1000 O (oersted), where M is at least one metal selected from the group comprising lithium, manganese, nickel, zinc, cadmium, copper, cobalt, and magnesium.
Inventors
- 👤 Hidekiyo Tachibana
- 👤 Akihiko Noda
- 👤 Kazuo Terao
- 👤 Toshio Honjou
- 👤 Yukio Seki
- 👤 Hiroshi Endo
- 👤 Toshio Yokobari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 16:58
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/10; G03G9/107; G03G9/1075
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
76 words
A carrier for a developer composed of a composition represented by the formula (CuO) a (ZnO) b (Fe 2 O 3 ) c , wherein a(mol)+b(mol)+c(mol)=1, 0.17≦a+b/c<0.42, a is in the range from 0.1 to 0.3, b in the range from 0.05 to 0.15, and c in the range from 0.7 to 0.8, said composition having a bulk density of 1.8-3.4 g/cm 3 and a magnetization of 10-30 emu/g in a magnetic field of 450-500 Oe(oerested).
Claim 2
Dependent Claim
76 words
A carrier for a developer composed of a composition represented by the formula (CuO) a (ZnO) b (Fe 2 O 3 ) c , wherein a(mol)+b(mol)+c(mol)=1, 0.17≦a+b/c<0.42, a is in the range from 0.1 to 0.3, b in the range from 0.05 to 0.15, and c in the range from 0.7 to 0.8, said composition having a bulk density of 1.8-3.4 g/cm 3 and a magnetization of 10-30 emu/g in a magnetic field of 450-500 Oe(oerested).
Claim 3
Dependent Claim
23 words
The carrier for a developer according to claim 1, wherein said carrier is comprised of particles having said composition coated with a resin.
Claim 4
Dependent Claim
15 words
The carrier for a developer according to claim 2, wherein said resin is styrene resin.
Claim 5
Dependent Claim
15 words
The carrier for a developer according to claim 3, wherein said resin is fluoro resin.
Claim 6
Dependent Claim
88 words
A developer comprising a mixture of a toner and a carrier for said toner, said carrier composed of a composition represented by the formula (CuO) a (ZnO) b (Fe 2 O 3 ) c , wherein a(mol)+b(mol)+c(mol)=1, 0.17≦a+b/c<0.42, and a is in the range from 0.1 to 0.3, b in the range from 0.05 to 0.15, and c in the range from 0.7 to 0.8, said composition having a bulk density of 1.8-3.4 g/cm 3 and a magnetization of 10-30 emu/g in a magnetic field of 450-500 Oe(oersted).
Claim 7
Dependent Claim
88 words
A developer comprising a mixture of a toner and a carrier for said toner, said carrier composed of a composition represented by the formula (CuO) a (ZnO) b (Fe 2 O 3 ) c , wherein a(mol)+b(mol)+c(mol)=1, 0.17≦a+b/c<0.42, and a is in the range from 0.1 to 0.3, b in the range from 0.05 to 0.15, and c in the range from 0.7 to 0.8, said composition having a bulk density of 1.8-3.4 g/cm 3 and a magnetization of 10-30 emu/g in a magnetic field of 450-500 Oe(oersted).
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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) | 1993-02-05 | 1993-08-07 | 1994-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-05 | 1997-08-07 | 1998-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-05 | 2001-08-07 | 2002-02-06 | $7700.00 | Window Closed / Lapsed |