Patent US4299900A successfully refreshed from Google Patents.
US4299900A
Expired / Lapsed
US
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Electrostatic image magnetic developing process
Assignee: Canon Inc
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Filing: 1980-03-10
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Granted: 1981-11-10
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Expires: 2000-03-10
Abstract
Abstract A process for development comprises arranging an electrostatic image bearing member having electrostatic images on the surface and a developer carrying member at a predetermined space, an insulating magnetic developer containing 10-50% by weight of magnetic toner particles 20-35 microns in size being carried on the developer carrying member in a thickness thinner than the predetermined space, and transferring the insulating magnetic developer to the electrostatic image bearing member in the presence of a magnetic field. According to this process for development, there can be produced developed images of high fidelity, high density and high resolution and free from fog.
Inventors
- 👤 Yasuo Mitsuhashi
- 👤 Masashi Kiuchi
- 👤 Yoshio Takasu
- 👤 Hiroshi Fukumoto
- 👤 Takashi Hino
- 👤 Masaki Uchiyama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:41
CPC Classifications
G; G03; G03G; G03G13/00; G03G13/06; G03G13/08; G03G13/09
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
127 words
A process for developing an electrostatic image which comprises the steps of: defining a developing zone by disposing an electrostatic image bearing member having an electrostatic image on the surface thereof and a developer carrying member in opposed relationship and with a clearance therebetween; providing a layer of magnetic developer on the surface of said developer carrying member having a thickness less than the distance defined by said clearance at the developing zone, wherein said magnetic developer is insulating so as to generate and maintain a triboelectric charge and contains 10-50 percent by weight of magnetic toner particles which are 20-35 microns in size; and electrically transferring the magnetic developer having a triboelectric charge to the electrostatic image bearing member in the presence of a magnetic field.
Claim 2
Dependent Claim
127 words
A process for developing an electrostatic image which comprises the steps of: defining a developing zone by disposing an electrostatic image bearing member having an electrostatic image on the surface thereof and a developer carrying member in opposed relationship and with a clearance therebetween; providing a layer of magnetic developer on the surface of said developer carrying member having a thickness less than the distance defined by said clearance at the developing zone, wherein said magnetic developer is insulating so as to generate and maintain a triboelectric charge and contains 10-50 percent by weight of magnetic toner particles which are 20-35 microns in size; and electrically transferring the magnetic developer having a triboelectric charge to the electrostatic image bearing member in the presence of a magnetic field.
Claim 3
Dependent Claim
19 words
A process according to claim 1 in which the magnetic toner particles contain 10-50% by weight of magnetic powder.
Claim 4
Dependent Claim
29 words
A process according to claim 1 in which the insulating magnetic developer contains not more than 10% by weight of magnetic toner particles of a size exceeding 35 microns.
Claim 5
Dependent Claim
30 words
A process according to claim 1 in which the insulating magnetic developer contains not more than 1% of magnetic toner particles of a size of not more than 5 microns.
Claim 6
Dependent Claim
22 words
A process according to claim 1 in which the developer carrying member is a drum provided with a magnet inside the drum.
Claim 7
Dependent Claim
27 words
A process according to claim 1 in which the thickness of the layer of the insulating magnetic developer carried on the developer carrying member is 30-300 microns.
Claim 8
Dependent Claim
33 words
A process according to claim 1 in which the surface speed of the electrostatic image bearing member is substantially the same as that of the developer layer carried on the developer carrying member.
Claim 9
Dependent Claim
26 words
A process according to claim 1 in which a member controlling the thickness of the insulating magnetic developer carried on the developer carrying member is magnetizable.
Claim 10
Dependent Claim
24 words
A process according to claim 1 in which the surface magnetic flux density of the developer carrying member ranges from 200 to 1300 gauss.
Claim 11
Dependent Claim
19 words
A process according to claim 1 in which the surface magnetic flux density ranges from 600 to 1300 gauss.
Claim 12
Dependent Claim
24 words
A process according to claim 1 in which an AC bias is applied between the developer carrying member and the electrostatic image bearing member.
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) | 1984-11-09 | 1985-05-11 | 1985-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-11-09 | 1989-05-11 | 1989-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-11-09 | 1993-05-11 | 1993-11-10 | $7700.00 | Window Closed / Lapsed |