Patent US4486089A successfully refreshed from Google Patents.
US4486089A
Expired / Lapsed
US
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Magnetic brush developing means
Assignee: Konica Minolta Inc
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Filing: 1982-07-26
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Granted: 1984-12-04
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Expires: 2002-07-26
Abstract
Abstract A magnetic brush developing apparatus for an electrophotographic copying machine or electrostatic recording machine has a sleeve in which a plurality of magnetic pieces are arranged in alternating polarity. Each piece has a shape which produces two or more magnetic peaks. The sleeve and the magnets are rotated in opposite directions. As a result of the the above, a soft developer body is obtained, and density unevenness or striping of the image is avoided.
Inventors
- 👤 Masahiko Itaya
- 👤 Satoshi Haneda
- 👤 Yukio Okamoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:13
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/09; G03G15/0921
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
96 words
In a magnetic brush developing means comprising a non-magnetic sleeve having a magnet therein for absorbing and carrying a developer comprising a magnetic material on the surface of said sleeve, and said developer developing an electrostatic latent image formed on a charge receptor, the improvement wherein said non-magnetic sleeve moves in the direction of the movement of said developer, and said magnet comprises a plurality of magnet pieces arranged circumferentially within said sleeve with alternating polarity, each magnet piece having a structure which provides a magnetic field strength distribution with a plurality of circumferentially spaced peaks.
Claim 2
Dependent Claim
96 words
In a magnetic brush developing means comprising a non-magnetic sleeve having a magnet therein for absorbing and carrying a developer comprising a magnetic material on the surface of said sleeve, and said developer developing an electrostatic latent image formed on a charge receptor, the improvement wherein said non-magnetic sleeve moves in the direction of the movement of said developer, and said magnet comprises a plurality of magnet pieces arranged circumferentially within said sleeve with alternating polarity, each magnet piece having a structure which provides a magnetic field strength distribution with a plurality of circumferentially spaced peaks.
Claim 3
Dependent Claim
18 words
A magnetic brush developing means according to claim 1 wherein said magnetic pieces are of a concaved structure.
Claim 4
Dependent Claim
29 words
A magnetic brush developing means according to claim 2, wherein each of said magnetic pieces has opposed protrudent sides connected by a center portion which is flat and concave.
Claim 5
Dependent Claim
25 words
A magnetic brush developing means according to claim 1, wherein said magnet rotates in a direction opposite to the direction of rotation of said sleeve.
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) | 1987-12-04 | 1988-06-04 | 1988-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-04 | 1992-06-04 | 1992-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-04 | 1996-06-04 | 1996-12-04 | $7700.00 | Window Closed / Lapsed |