US4448870A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic color toner
Assignee: Canon Inc
•
Filing: 1983-04-11
•
Granted: 1984-05-15
•
Expires: 2003-04-11
Abstract
Abstract Red to sepia magnetic toners stable to heat and light which do not fade or discolor for a long period of time are prepared by incorporating a partially α-transformed γ-Fe 2 O 3 as a component in a toner.
Inventors
- 👤 Eiichi Imai
- 👤 Hitoshi Uchide
- 👤 Kazunori Murakawa
- 👤 Masaki Uchiyama
- 👤 Hisayuki Ochi
- 👤 Motoo Urawa
- 👤 Seiichi Takagi
- 👤 Yasuo Mitsuhashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:15
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/083; G03G9/0831; G03G9/0833; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/104
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
30 words
A magnetic color toner containing a magnetic material and a binder, said magnetic material comprising magnetic particles comprising a mixture of α-Fe 2 O 3 and γ-Fe 2 O 3
Claim 2
Dependent Claim
30 words
A magnetic color toner containing a magnetic material and a binder, said magnetic material comprising magnetic particles comprising a mixture of α-Fe 2 O 3 and γ-Fe 2 O 3
Claim 3
Dependent Claim
27 words
The magnetic color toner of claim 1, wherein the amount of said magnetic material is 20-100 parts by weight to 100 parts by weight of said binder.
Claim 4
Dependent Claim
22 words
The magnetic color toner of claim 1, wherein the α-Fe 2 O 3 content in said magnetic material is 1-50% by weight.
Claim 5
Dependent Claim
25 words
The magnetic color toner of claim 1, wherein the content of said magnetic particles in the entire magnetic material is at least 60% by weight.
Claim 6
Dependent Claim
23 words
The magnetic color toner of claim 1, which additionally contains a colorant in amounts sufficient to provide a hue from red to sepia.
Claim 7
Dependent Claim
39 words
The magnetic color toner of claim 1, wherein said magnetic particles are prepared by neutralizing an iron sulfate or iron chloride solution with alkali, oxidizing the resultant with heat, and further oxidizing the resulting Fe 3 O 4 .
Claim 8
Dependent Claim
30 words
The magnetic color toner of claim 1, wherein said magnetic particles are prepared by oxidizing the Fe 3 O 4 coprecipitated from a solution of a ferrous salt-ferric salt mixture.
References Cited (Backward Citations)
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Cited
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Cited
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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) | 1987-05-15 | 1987-11-14 | 1988-05-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-05-15 | 1991-11-14 | 1992-05-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-05-15 | 1995-11-14 | 1996-05-15 | $7700.00 | Window Closed / Lapsed |