US4265993A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic toner for electrostatic images and transfer copying
Assignee: Proterial Ltd
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Filing: 1979-06-26
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Granted: 1981-05-05
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Expires: 1999-06-26
Abstract
Abstract Magnetic toner employable as a developer for electrophotographic duplication system consisting of the steps of developing electrostatic latent image on a carrier, overlaying a copying sheet on said carrier of developed image, and transferring the developed image to said sheet, characterized by containing magnetic fine particles of a electric resistivity from 10 9 ˜10 16 Ω·cm (at 4000 V/cm DC) and dielectric constant from 2.6˜5.
Inventors
- 👤 Tsuneaki Kawanishi
- 👤 Akio Mukoh
- 👤 Hirosada Morishita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 04:49
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/083; G03G9/0837; G03G9/0821; G03G9/0823; G03G9/0836; G03G9/087; G03G9/08702; G03G9/08706; G03G9/08708; G03G9/08711; G03G9/08726; G03G9/08728; Y; Y10; Y10S; Y10S430/00; Y10S430/001; Y10S430/104; Y10S430/105; Y10T; Y10T428/00; Y10T428/29; Y10T428/2982; Y10T428/2991; Y10T428/2998
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
112 words
A magnetic toner composition for the development of electrostatic latent images and for electrostatic transfer-copying comprising a magnetic powder and a resin, wherein said resinous component contains at least one monomer from each of monomer groups (1) to (3), wherein group (1) includes ##STR1## wherein R 1 is an alkyl radical containing from 1 to 12 carbon atoms, and R 2 is an alkyl radical containing from 2 to 12 carbon atoms, and further wherein said composition has a particulate diameter ranging between 3 and 30 μm, an electric resistivity ranging from between 10 9 and 10 6 ohm·cm at 4000 volts/cm DC and a dielectric constant ranging between 2.6 and 5.
Claim 2
Dependent Claim
112 words
A magnetic toner composition for the development of electrostatic latent images and for electrostatic transfer-copying comprising a magnetic powder and a resin, wherein said resinous component contains at least one monomer from each of monomer groups (1) to (3), wherein group (1) includes ##STR1## wherein R 1 is an alkyl radical containing from 1 to 12 carbon atoms, and R 2 is an alkyl radical containing from 2 to 12 carbon atoms, and further wherein said composition has a particulate diameter ranging between 3 and 30 μm, an electric resistivity ranging from between 10 9 and 10 6 ohm·cm at 4000 volts/cm DC and a dielectric constant ranging between 2.6 and 5.
Claim 3
Dependent Claim
45 words
The magnetic toner of claim 1 wherein said resinous component contains 5 to 20% by mol of the monomer of group (1), 20 to 60% by mol of the monomer of group (2), and 20 to 75% by mol of said monomer of group (3).
Claim 4
Dependent Claim
23 words
Magnetic toner as set forth in claim 2 characterized by containing carbon black of 0.05˜0.5% by weight on the base of toner amount.
Claim 5
Dependent Claim
21 words
The magnetic toner of claim 1 wherein a portion of the monomer of group (2) is replaced by the monomer ##STR2##
Claim 6
Dependent Claim
46 words
The magnetic toner of claim 1 wherein said resinous component has a glass transition temperature higher than 50° C. and a softening point temperature lower than the fixing temperature used when said magnetic toner composition is used to develop electrostatic latent images or for electrostatic transfer-copying.
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) | 1984-05-04 | 1984-11-03 | 1985-05-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-04 | 1988-11-03 | 1989-05-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-04 | 1992-11-03 | 1993-05-05 | $7700.00 | Window Closed / Lapsed |