US5025288A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Image forming apparatus capable of preventing simultaneous rotation of the magnet roll and the developing sleeve
Assignee: Minolta Co Ltd
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Filing: 1989-10-31
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Granted: 1991-06-18
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Expires: 2009-10-31
Abstract
Abstract An image forming apparatus arranged to develop an electrostatic latent image formed on an electrostatic latent image holding member, and including a developing sleeve rotatably provided to confront the electrostatic latent image holding member, a sleeve driving device for rotating the developing sleeve, a magnet roller provided within the developing sleeve and having a plurality of magnetic poles, a magnet roller driving device for rotating the magnet roller through a predetermined angle, with the magnet roller driving device being arranged to rotate the magnet roller between a first state where its magnetic pole confronts the electrostatic latent image holding member and a second state where an intermediate portion between neighboring magnetic poles confronts the electrostatic latent image holding member, and a control unit for controlling the sleeve driving device and the magnet roller driving device in such a manner as to rotate the magnetic poles of the magnet roller from the first state to the second state after stopping rotation of the developing sleeve when the developing function is to be completed. A bias voltage is applied to the developing sleeve such that the amount of bias voltage applied to the developing sleeve is change from a first value to a second value upon stopping rotation of the developing sleeve or following rotation of the magnet roller, the first value being closer to zero than the second value.
Inventors
- 👤 Yasuhiro Kusuda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:40
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/01; G03G15/0105; G03G15/0126; G03G15/06; G03G15/08; G03G15/09
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
179 words
An image forming apparatus arranged to develop an electrostatic latent image formed on an electrostatic latent image holding member by use of toner, said image forming apparatus comprising: a developing sleeve rotatably provided to confront the electrostatic latent image holding member, a sleeve driving means for rotating said developing sleeve, a magnet roller provided within said developing sleeve and having a plurality of magnetic poles, a magnet roller driving means for rotating said magnet roller through a predetermined angle, said magnet roller driving means being arranged to rotate said magnet roller between a first state where a magnetic pole thereof confronts the electrostatic latent image holding member and a second state where an intermediate portion between neighboring magnetic poles confronts said electrostatic latent image holding member, and a control means for controlling said sleeve driving means and said magnet roller driving means in such a manner as to rotate the magnetic poles of said magnet roller from the first state to the second state after stopping rotation of said developing sleeve when the developing function is to be completed.
Claim 2
Dependent Claim
179 words
An image forming apparatus arranged to develop an electrostatic latent image formed on an electrostatic latent image holding member by use of toner, said image forming apparatus comprising: a developing sleeve rotatably provided to confront the electrostatic latent image holding member, a sleeve driving means for rotating said developing sleeve, a magnet roller provided within said developing sleeve and having a plurality of magnetic poles, a magnet roller driving means for rotating said magnet roller through a predetermined angle, said magnet roller driving means being arranged to rotate said magnet roller between a first state where a magnetic pole thereof confronts the electrostatic latent image holding member and a second state where an intermediate portion between neighboring magnetic poles confronts said electrostatic latent image holding member, and a control means for controlling said sleeve driving means and said magnet roller driving means in such a manner as to rotate the magnetic poles of said magnet roller from the first state to the second state after stopping rotation of said developing sleeve when the developing function is to be completed.
Claim 3
Dependent Claim
75 words
An image forming apparatus as claimed in claim 1, further comprising means for applying a bias voltage to the developing sleeve, and a bias voltage control means for controlling said bias voltage applying means so as to change an amount of the bias voltage applied to the developing sleeve from a first value to a second value upon stopping rotation of said developing sleeve, the first value being closer to zero than the second value.
Claim 4
Dependent Claim
60 words
An image forming apparatus as claimed in claim 2, wherein said bias voltage control means is adapted to control said bias voltage applying means so as to further change the amount of the bias voltage from the second value to a third value following rotation of said magnet roller, the third value being closer to zero than the second value.
Claim 5
Dependent Claim
74 words
An image forming apparatus as claimed in claim 1, further comprising means for applying a bias voltage to the developing sleeve, and a bias voltage control means for controlling said bias voltage applying means so as to change an amount of the bias voltage applied to the developing sleeve from a first value to a second value following rotation of said magnet roller, the first value being closer to zero than the second value.
Claim 6
Dependent Claim
75 words
An image forming apparatus as claimed in claim 1, further comprising means for applying a bias voltage to the developing sleeve, and a bias voltage control means for controlling said bias voltage applying means so as to change an amount of the bias voltage applied to the developing sleeve from a first value to a second value upon stopping rotation of said developing sleeve for preventing the toner from adhering to the electrostatic latent image.
Claim 7
Dependent Claim
58 words
An image forming apparatus as claimed in claim 5, wherein said bias voltage control means is adapted to control said bias voltage applying means so as to further change the amount of the bias voltage from the second value to a third value following rotation of said magnet roller, the third value being equal to the first value.
Claim 8
Dependent Claim
232 words
An image forming apparatus arranged to develop an electrostatic latent image formed on an electrostatic latent image holding member, said image forming apparatus comprising: a developing sleeve rotatably provided to confront the electrostatic latent image holding member, a sleeve driving means for rotating said developing sleeve, a magnet roller provided within said developing sleeve and having a plurality of magnetic poles, a magnet roller driving means for rotating said magnet roller through a predetermined angle, said magnet roller driving means being arranged to rotate said magnet roller between a first state where a magnetic pole thereof confronts the electrostatic latent image holding member and a second state where an intermediate portion between neighboring magnetic poles confronts said electrostatic latent image holding member, means for applying a bias voltage to said developing sleeve, and control means for controlling said sleeve driving means and said magnet roller driving means so as to start rotation of the developing sleeve after having rotated the magnetic poles of said magnet roller from said second state to said first state when the developing function is to be started, and also for controlling said bias voltage applying means so as to change an amount of the bias voltage applied to said developing sleeve from a first value to a second value upon starting rotation of said developing sleeve, the second value being closer to zero than the first value.
Claim 9
Dependent Claim
232 words
An image forming apparatus arranged to develop an electrostatic latent image formed on an electrostatic latent image holding member, said image forming apparatus comprising: a developing sleeve rotatably provided to confront the electrostatic latent image holding member, a sleeve driving means for rotating said developing sleeve, a magnet roller provided within said developing sleeve and having a plurality of magnetic poles, a magnet roller driving means for rotating said magnet roller through a predetermined angle, said magnet roller driving means being arranged to rotate said magnet roller between a first state where a magnetic pole thereof confronts the electrostatic latent image holding member and a second state where an intermediate portion between neighboring magnetic poles confronts said electrostatic latent image holding member, means for applying a bias voltage to said developing sleeve, and control means for controlling said sleeve driving means and said magnet roller driving means so as to start rotation of the developing sleeve after having rotated the magnetic poles of said magnet roller from said second state to said first state when the developing function is to be started, and also for controlling said bias voltage applying means so as to change an amount of the bias voltage applied to said developing sleeve from a first value to a second value upon starting rotation of said developing sleeve, the second value being closer to zero than the first value.
Claim 10
Dependent Claim
231 words
An image forming apparatus arranged to develop an electrostatic latent image formed on an electrostatic latent image holding member, said image forming apparatus comprising: a developing sleeve rotatably provided to confront the electrostatic latent image holding member, a sleeve driving means for rotating said developing sleeve, a magnet roller provided within said developing sleeve and having a plurality of magnetic poles, a magnet roller driving means for rotating said magnet roller through a predetermined angle, said magnet roller driving means being arranged to rotate said magnet roller between a first state where a magnetic pole thereof confronts the electrostatic latent image holding member and a second state where an intermediate portion between neighboring magnetic poles confronts said electrostatic latent image holding member, means for applying a bias voltage to said developing sleeve, and control means for controlling said sleeve driving means and said magnet roller driving means so as to start rotation of the developing sleeve after having rotated the magnetic poles of said magnet roller from said second state to said first state when the developing function is to be started, and also for controlling said bias voltage applying means so as to change an amount of the bias voltage applied to said developing sleeve from a first value to a second value following rotation of said magnet roller, the second value being closer to zero than the first value.
Claim 11
Dependent Claim
231 words
An image forming apparatus arranged to develop an electrostatic latent image formed on an electrostatic latent image holding member, said image forming apparatus comprising: a developing sleeve rotatably provided to confront the electrostatic latent image holding member, a sleeve driving means for rotating said developing sleeve, a magnet roller provided within said developing sleeve and having a plurality of magnetic poles, a magnet roller driving means for rotating said magnet roller through a predetermined angle, said magnet roller driving means being arranged to rotate said magnet roller between a first state where a magnetic pole thereof confronts the electrostatic latent image holding member and a second state where an intermediate portion between neighboring magnetic poles confronts said electrostatic latent image holding member, means for applying a bias voltage to said developing sleeve, and control means for controlling said sleeve driving means and said magnet roller driving means so as to start rotation of the developing sleeve after having rotated the magnetic poles of said magnet roller from said second state to said first state when the developing function is to be started, and also for controlling said bias voltage applying means so as to change an amount of the bias voltage applied to said developing sleeve from a first value to a second value following rotation of said magnet roller, the second value being closer to zero than the first value.
Claim 12
Dependent Claim
183 words
An image forming apparatus arranged to develop an electrostatic latent image formed on an electrostatic latent image holding member, said image forming apparatus comprising: a developing sleeve rotatably provided to confront the electrostatic latent image holding member, a sleeve driving means for rotating said developing sleeve, a magnet roller provided within said developing sleeve and having a plurality of magnetic poles, a magnet roller driving means for rotating said magnet roller through a predetermined angle, said magnet roller driving means being arranged to rotate said magnet roller between a first state where a magnetic pole thereof confronts the electrostatic latent image holding member and a second state where an intermediate portion between neighboring magnetic poles confronts said electrostatic latent image holding member, and a control means for controlling said sleeve driving means and said magnet roller driving means in such a manner as to rotate the magnetic poles of said magnet roller from the first state to the second state after passing a predetermined period of time subsequent to stopping rotation of said developing sleeve when the developing function is to be completed.
Claim 13
Dependent Claim
183 words
An image forming apparatus arranged to develop an electrostatic latent image formed on an electrostatic latent image holding member, said image forming apparatus comprising: a developing sleeve rotatably provided to confront the electrostatic latent image holding member, a sleeve driving means for rotating said developing sleeve, a magnet roller provided within said developing sleeve and having a plurality of magnetic poles, a magnet roller driving means for rotating said magnet roller through a predetermined angle, said magnet roller driving means being arranged to rotate said magnet roller between a first state where a magnetic pole thereof confronts the electrostatic latent image holding member and a second state where an intermediate portion between neighboring magnetic poles confronts said electrostatic latent image holding member, and a control means for controlling said sleeve driving means and said magnet roller driving means in such a manner as to rotate the magnetic poles of said magnet roller from the first state to the second state after passing a predetermined period of time subsequent to stopping rotation of said developing sleeve when the developing function is to be completed.
References Cited (Backward Citations)
US3572288A
Cited
US3914043A
Cited
US4755850A
Cited
US4461562A
Cited
US4579443A
Cited
JPS61203474A
Cited
US4804995A
Cited
JPS62108063A
Cited
US4862216A
Cited
US4885611A
Cited
US4891671A
Cited
US4866486A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-06-17 | 1994-12-17 | 1995-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-06-17 | 1998-12-17 | 1999-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-06-17 | 2002-12-17 | 2003-06-18 | $7700.00 | Window Closed / Lapsed |