US4868601A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Developing unit for electrophotography with toner sensor
Assignee: Sharp Corp
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Filing: 1988-02-25
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Granted: 1989-09-19
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Expires: 2008-02-25
Abstract
Abstract A developing unit for electrophotography has a magnet roller disposed opposite to its photosensitive drum and a toner sensor disposed near the magnet roller and displaced from the position of one of the poles of the magnet roller by 5°-15° in the direction of the photosensitive drum.
Inventors
- 👤 Kenichi Morimoto
- 👤 Akiyoshi Fujihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:41
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/0822; G03G15/0848; G03G15/0849
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
120 words
In a developing unit for electrophotography including a magnet roller disposed opposite to a photosensitive drum, a doctor blade for controlling the amount of developing agent adsorbed on said magnet roller, and a toner sensor adapted to measure toner concentration, the improvement wherein said toner sensor is disposed at a position near said magnet roller and displaced from the position of a magnetic pole of said magnet roller by 5°-15° in the direction toward said photosensitive drum, the distance T defined by T=T 2 -T 1 being between zero and -0.6 mm where T 1 is the separation between said magnet roller and said doctor blade and T 2 is the separation between said toner sensor and said magnet roller.
Claim 2
Dependent Claim
120 words
In a developing unit for electrophotography including a magnet roller disposed opposite to a photosensitive drum, a doctor blade for controlling the amount of developing agent adsorbed on said magnet roller, and a toner sensor adapted to measure toner concentration, the improvement wherein said toner sensor is disposed at a position near said magnet roller and displaced from the position of a magnetic pole of said magnet roller by 5°-15° in the direction toward said photosensitive drum, the distance T defined by T=T 2 -T 1 being between zero and -0.6 mm where T 1 is the separation between said magnet roller and said doctor blade and T 2 is the separation between said toner sensor and said magnet roller.
Claim 3
Dependent Claim
18 words
The developing unit of claim 1 wherein said magnet roller comprises two south poles and one north pole.
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) | 1992-09-18 | 1993-03-20 | 1993-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-09-18 | 1997-03-20 | 1997-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-09-18 | 2001-03-20 | 2001-09-19 | $7700.00 | Window Closed / Lapsed |