Patent US842477A successfully refreshed from Google Patents.
Patent US4284702A successfully refreshed from Google Patents.
US4284702A
Expired / Lapsed
US
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Electrographic developing method
Assignee: Minolta Co Ltd
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Filing: 1979-12-17
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Granted: 1981-08-18
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Expires: 1999-12-17
Abstract
Abstract An electrographic developing method comprising forming a magnetic brush of a developer composed of at least two components of insulating toner particles and insulating carrier granules, and brushing a surface bearing an electrostatic latent image with the brush to render the latent image visible, the carrier granules having the properties of (1) triboelectrifying the toner particles to a polarity suitable for developing the latent image by coming into frictional contact with the toner particles, (2) being magnetic, (3) having a resistivity of at least 10 12 ohm-cm, and (4) being 5 to 40 μm in size.
Inventors
- 👤 Kenji Tabuchi
- 👤 Susumu Tanaka
- 👤 Kenichi Wada
- 👤 Tateki Oka
- 👤 Hiroaki Mizunoe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 19:58
CPC Classifications
G; G03; G03G; G03G9/00; G03G9/08; G03G9/083; G03G13/00; G03G13/06; G03G13/08; G03G13/09; G03G9/10; G03G9/107; G03G9/1087
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
182 words
An electrographic developing method for developing electrostatic latent images which comprises the steps of: (1) mixing insulating non-magnetic toner particles and carrier granules consisting essentially of an electrical insulating resin and at least 50%, by weight of the carrier granules, of magnetizable fine particles where the carrier granules have the properties of (1) triboelectrically charging the toner particles to a polarity suitable for developing the latent image by frictional contact with the toner particles, (2) being magnetic, (3) having an electro-resistivity of at least 10 12 ohm-cm, and (4) being all substantially within the size range of 5 to 40 μm; said toner particles being present in an amount of 2-50% by weight of the toner-carrier mixture; (2) magnetically attracting said mixture onto a developing sleeve which opposes a recording medium with narrow clearance at the developing station of 1.0 mm and under; and (3) flowing said mixture around the developing sleeve and to the developing station for applying said mixture on an electrostatic latent image formed on the recording medium and for developing said electrostatic latent image into a visible image.
Claim 2
Dependent Claim
182 words
An electrographic developing method for developing electrostatic latent images which comprises the steps of: (1) mixing insulating non-magnetic toner particles and carrier granules consisting essentially of an electrical insulating resin and at least 50%, by weight of the carrier granules, of magnetizable fine particles where the carrier granules have the properties of (1) triboelectrically charging the toner particles to a polarity suitable for developing the latent image by frictional contact with the toner particles, (2) being magnetic, (3) having an electro-resistivity of at least 10 12 ohm-cm, and (4) being all substantially within the size range of 5 to 40 μm; said toner particles being present in an amount of 2-50% by weight of the toner-carrier mixture; (2) magnetically attracting said mixture onto a developing sleeve which opposes a recording medium with narrow clearance at the developing station of 1.0 mm and under; and (3) flowing said mixture around the developing sleeve and to the developing station for applying said mixture on an electrostatic latent image formed on the recording medium and for developing said electrostatic latent image into a visible image.
Claim 3
Dependent Claim
20 words
An electrographic developing method as claimed in claim 1, wherein said carrier granules are 5 to 30 μm in size.
Claim 4
Dependent Claim
20 words
An electrographic developing method as claimed in claim 1, wherein said carrier granules are 10 to 25 μm in size.
Claim 5
Dependent Claim
22 words
An electrographic developing method as claimed in claim 1, wherein said carrier granules have an electro-resistivity of at least 10 14 ohm-cm.
Claim 6
Dependent Claim
31 words
An electrographic developing method as claimed in claim 1, wherein said carrier granules contain the magnetizable fine particles in the proportion of 50 to 75wt% based on the whole carrier granules.
Claim 7
Dependent Claim
32 words
An electrographic developing method as claimed in claim 5, further comprises a step of: transferring said visible image onto copy paper from the recording medium with use of a corona discharge unit.
Claim 8
Dependent Claim
35 words
An electrographic developing method as claimed in claim 6, further comprises a step of: recovering the carrier granules remaining on the recording medium after the transfer for the reuse of the carrier granules for development.
Claim 9
Dependent Claim
17 words
An electrographic developing method as claimed in claim 1, wherein said clearance is 0.5 to 1.0 mm.
Claim 10
Dependent Claim
31 words
An electrographic developing method as claimed in claim 1, wherein said step (3) is accomplished by rotating a multi-pole magnetic roller within the developing sleeve, while holding said developing sleeve stationary.
Claim 11
Dependent Claim
25 words
An electrographic developing method as claimed in claim 1, wherein the carrier granules are triboelectrically charged to a polarity opposite that of the toner particles.
Claim 12
Dependent Claim
31 words
An electrographic developing method as claimed in claim 1, wherein there is mounted on the developing sleeve a rotatable magnetic roller which is rotated during the development of the electrostatic image.
Claim 13
Dependent Claim
44 words
An electrographic developing method as claimed in claim 11, wherein during the developing operation, the magnetic roller is rotated and the recording medium is swept by a magnetic brush formed of said mixtures of toner particles and carrier to develop the electrostatic latent image.
Claim 14
Dependent Claim
15 words
An electrographic developing method is claimed in claim 1, wherein the developing sleeve is rotatable.
References Cited (Backward Citations)
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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) | 1984-08-17 | 1985-02-16 | 1985-08-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-08-17 | 1989-02-16 | 1989-08-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-08-17 | 1993-02-16 | 1993-08-18 | $7700.00 | Window Closed / Lapsed |