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US4187330A
Expired / Lapsed
US
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Electrostatic developing method and apparatus using conductive magnetic toner
Assignee: Proterial Ltd
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Filing: 1977-01-25
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Granted: 1980-02-05
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Expires: 1997-01-25
Abstract
Abstract A method for developing an electrostatic latent image and an apparatus therefor, in which a magnetic toner layer is formed on an arcuate face formed from an insulator, and an electrostatic latent image carrying medium is supported such that its electrostatic latent image surface contacts lightly with a part of said magnetic toner layer.
Inventors
- 👤 Hideki Harada
- 👤 Keitarou Yamashita
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:01
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/09; G03G15/0914; G03G15/0921
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
146 words
An electrostatic developing method comprising the steps of: (a) attracting magnetic and inductively chargeable electroconductive toner particles which have a volume resistance ranging between 10 2 and 10 5 Ω-cm in a D.C. electric-field of 100 V/cm, on an insulating carrier by a magnetic force of a permanent magnet means, (b) carrying the toner particles in brush form on said insulating carrier close to an electrostatic latent image on an electrostatic latent image bearing medium, (c) oppositely charging inductively the tips of the toner particles adjacent to the electrostatic latent image to that of the latent image, an electrode being provided to electrically contact the toner particles and being electrically connected with the image bearing medium, and (d) attracting a part of the toner particles adjacent to the electrostatic latent image by means of an electric attraction force between the toner particles and the latent image.
Claim 2
Dependent Claim
146 words
An electrostatic developing method comprising the steps of: (a) attracting magnetic and inductively chargeable electroconductive toner particles which have a volume resistance ranging between 10 2 and 10 5 Ω-cm in a D.C. electric-field of 100 V/cm, on an insulating carrier by a magnetic force of a permanent magnet means, (b) carrying the toner particles in brush form on said insulating carrier close to an electrostatic latent image on an electrostatic latent image bearing medium, (c) oppositely charging inductively the tips of the toner particles adjacent to the electrostatic latent image to that of the latent image, an electrode being provided to electrically contact the toner particles and being electrically connected with the image bearing medium, and (d) attracting a part of the toner particles adjacent to the electrostatic latent image by means of an electric attraction force between the toner particles and the latent image.
Claim 3
Dependent Claim
28 words
An electrostatic developing method according to claim 1, wherein the permanent magnet means and the insulating carrier are rotated relative to each other for carrying the toner particles.
Claim 4
Dependent Claim
23 words
An electrostatic developing method according to claim 1, wherein a voltage differential between the electrode and the medium are impressed during the development.
Claim 5
Dependent Claim
28 words
An electrostatic developing method according to claim 2, wherein the permanent magnet means and the insulating carrier are rotated in the same direction for carrying the toner particles.
Claim 6
Dependent Claim
32 words
An electrostatic developing method according to claim 1, wherein the magnet means comprises a magnet roll and an insulating plastic sleeve disposed around the magnet roll is used as the insulating carrier.
Claim 7
Dependent Claim
25 words
An electrostatic developing method according to claim 5 wherein said magnet roll and said insulating plastic sleeve are arranged to rotate relatively to each other.
Claim 8
Dependent Claim
22 words
An electrostatic developing method according to claim 1, wherein a voltage is applied between the magnetic toner and the electrostatic latent image.
Claim 9
Dependent Claim
16 words
An electrostatic developing method according to claim 1, wherein the insulating carrier is a ferrite magnet.
Claim 10
Dependent Claim
18 words
An electrostatic developing method according to claim 1, wherein no joint is present in a magnetic pole portion.
Claim 11
Dependent Claim
19 words
An electrostatic developing method according to claim 1, wherein an integral columnar ferrite magnet is used as said carrier.
Claim 12
Dependent Claim
27 words
An electrostatic developing method according to claim 1, wherein the volume resistance of the conductive toner is within the range of 10 2 to 10 4 Ω-cm.
Claim 13
Dependent Claim
23 words
An electrostatic developing method according to claim 1, wherein the volume resistance of the carrier is greater than that of the conductive toner.
Claim 14
Dependent Claim
20 words
An electrostatic developing method according to claim 12, wherein electric resistance of the carrier is higher than 10 7 Ω-cm.
Claim 15
Dependent Claim
17 words
An electrostatic developing method according to claim 13, wherein the conductive toner is previously rendered neutral electrostatically.
References Cited (Backward Citations)
US3124457A
Cited
DE2538122A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1983-02-04 | 1983-08-06 | 1984-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-02-04 | 1987-08-06 | 1988-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-02-04 | 1991-08-06 | 1992-02-05 | $7700.00 | Window Closed / Lapsed |