Patent US4433042A successfully refreshed from Google Patents.
US4433042A
Expired / Lapsed
US
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Electrophotographic developing method using magnetic toners
Assignee: Proterial Ltd
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Filing: 1981-12-03
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Granted: 1984-02-21
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Expires: 2001-12-03
Abstract
Abstract Electrophotographic copying is carried out by electrostatically forming a latent image on a recording medium, supplying a magnetic toner of single component system containing at least a resin and fine particles of forromagnetic material on a non-magnetic sleeve provided with a permanent magnet roller having a plurality of magnetic poles therein, transporting the magnetic toner into a gap between the recording medium and the non-magnetic sleeve, attaching the magnetic toner to the recording medium, thereby developing the latent image into a visible image, electrostatically transferring the toner image thus formed on the recording medium onto a transfer sheet, and fixing the transferred image, thereby obtaining a final image, wherein the magnetic toner has a resistivity of more than 5×10 15 Ωcm and a relative dielectric constant of less than 3.0. Good development and good transferred image are obtained even with a recording medium having a low relative dielectric constant and a high insulating property, and practically high transfer efficiency can be obtained with the ordinary sheet having a low resistivity as a transfer sheet.
Inventors
- 👤 Tsuneaki Kawanishi
- 👤 Akio Mukoh
- 👤 Hirosada Morishita
- 👤 Nobuyoshi Hoshi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 17:50
CPC Classifications
G; G03; G03G; G03G13/00; G03G13/22; G03G9/00; G03G9/08; G03G9/0821; G03G9/0823; G03G9/083
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
155 words
A method for electrophotographic developing, the method comprising the steps of electrostatically forming a latent image on an organic photoconductive member, supplying a single component magnetic toner containing at least a resin and find particles of ferromagnetic material on a non-magnetic sleeve provided with a permanent magnetic means having a plurality of magnetic poles therein, the magnetic toner having a resistivity of more than 5×10 15 Ω.cm and a relative dielectric constant of less than 2.6, transporting the magnetic toner into a gap between the organic photoconductive member and the non-magnetic sleeve, attaching the magnetic toner to the organic photoconductive member, thereby developing the latent image into a visible image, electrostatically transferring the toner image thus formed on the organic photoconductive member onto a transfer sheet of ordinary paper having a low electric resistance with a bulk resistivity of not greater than 10 12 Ω.cm, and fixing the transferred image, thereby obtaining a final image.
Claim 2
Independent Claim
155 words
A method for electrophotographic developing, the method comprising the steps of electrostatically forming a latent image on an organic photoconductive member, supplying a single component magnetic toner containing at least a resin and find particles of ferromagnetic material on a non-magnetic sleeve provided with a permanent magnetic means having a plurality of magnetic poles therein, the magnetic toner having a resistivity of more than 5×10 15 Ω.cm and a relative dielectric constant of less than 2.6, transporting the magnetic toner into a gap between the organic photoconductive member and the non-magnetic sleeve, attaching the magnetic toner to the organic photoconductive member, thereby developing the latent image into a visible image, electrostatically transferring the toner image thus formed on the organic photoconductive member onto a transfer sheet of ordinary paper having a low electric resistance with a bulk resistivity of not greater than 10 12 Ω.cm, and fixing the transferred image, thereby obtaining a final image.
Claim 3
Dependent Claim
53 words
The method according to claim 1, wherein the magnetic toner contains 5 to 60% by weight of fine ferromagnetic particles on the basis of the toner, a fixing resin, color-controlling pigment or dye and a charge-controlling agent and an average particle size of the magnetic toner is in a range of 3-30 μm.
Claim 4
Dependent Claim
52 words
The method according to claim 2, wherein the magnetic toner particles are mixed with inorganic or organic particles with an average particle diameter ranging from 0.01 to 500 microns as a resistance and flowability-adjusting agent in an amount of 0.01 to 4% by weight on the basis of the all toner particles.
Claim 5
Dependent Claim
41 words
The method according to claim 3, wherein the magnetic toner particles are mixed with at least carbon black as a resistance and flowability-adjusting agent in an amount of 0.05 to 0.2% by weight on the basis of the all toner particles.
Claim 6
Dependent Claim
72 words
The method according to claim 1, further comprising the steps of adjusting a width of the gap between the organic photoconductive member and non-magnetic sleeve and a width of a doctor gap between the non-magnetic sleeve and supply of magnetic toner such that a width D of the gap between the organic photoconductive member and non-magnetic sleeve is in the range of d≦D≦d+0.1, wherein d is a width of the doctor gap.
Claim 7
Dependent Claim
42 words
The method according to claim 6, wherein the step of transporting the magnetic toner includes rotating the non-magnetic sleeve in the same direction as the permanent magnetic means at a speed of about one-third a rotational speed of the permanent magentic means.
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) | 1987-02-20 | 1987-08-22 | 1988-02-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-02-20 | 1991-08-22 | 1992-02-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-02-20 | 1995-08-22 | 1996-02-21 | $7700.00 | Window Closed / Lapsed |