Patent US3927641A successfully refreshed from Google Patents.
US3927641A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Developing mechanism using magnetic brush
Assignee: Fujifilm Business Innovation Corp
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Filing: 1974-05-10
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Granted: 1975-12-23
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Expires: 1994-05-10
Abstract
Abstract A magnetic brush type developing mechanism in an electronic copying machine characterized by being provided with at least two developing magnetic brush rolls having different applied bias voltages.
Inventors
- 👤 Kenichi Handa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:42
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/09; G03G15/0907; G03G13/00; G03G13/06; G03G13/08; G03G13/09
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
182 words
In a magnetic brush type developing mechanism having at least two developing magnetic brush rolls, said developing mechanism developing a latent image on a moving recording material with magnetic toner, the improvement comprising means for applying to a first magnetic brush roll encountered by said latent image a first potential, the absolute value of which is substantially greater than the absolute value of the background potential of said latent image and means for applying to a second magnetic brush roll immediately adjacent to said first roll and encountered by said latent image prior to said first roll a second potential, the absolute value of which is less than said absolute value of the background potential whereby development of the image portion of said latent image is enhanced due to the large potential difference between the potential of said image portion and said second potential while background fogging is lessened due to the large potential difference between said first potential and said background potential which attracts the magnetic toner from the space between said first and second magnetic rolls adjacent the recording material.
Claim 2
Dependent Claim
182 words
In a magnetic brush type developing mechanism having at least two developing magnetic brush rolls, said developing mechanism developing a latent image on a moving recording material with magnetic toner, the improvement comprising means for applying to a first magnetic brush roll encountered by said latent image a first potential, the absolute value of which is substantially greater than the absolute value of the background potential of said latent image and means for applying to a second magnetic brush roll immediately adjacent to said first roll and encountered by said latent image prior to said first roll a second potential, the absolute value of which is less than said absolute value of the background potential whereby development of the image portion of said latent image is enhanced due to the large potential difference between the potential of said image portion and said second potential while background fogging is lessened due to the large potential difference between said first potential and said background potential which attracts the magnetic toner from the space between said first and second magnetic rolls adjacent the recording material.
Claim 3
Dependent Claim
40 words
The improvement as in claim 1 including more than two of said magnetic brush rolls and means for applying said first potential to alternate rolls including said final roll and means for applying said second potential to the remaining rolls.
Claim 4
Dependent Claim
27 words
The improvement as in claim 1 where said first potential is 50 to 200 volts greater in absolute magnitude than said absolute value of the background potential.
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) | 1978-12-22 | 1979-06-23 | 1979-12-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-22 | 1983-06-23 | 1983-12-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-22 | 1987-06-23 | 1987-12-23 | $7700.00 | Window Closed / Lapsed |