US5946534A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus and method for non-interactive electrophotographic development
Assignee: Xerox Corp
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Filing: 1998-01-08
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Granted: 1999-08-31
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Expires: 2018-01-08
Abstract
Abstract An apparatus and method for non-interactive, dry powder development of electrostatic images including: an image bearing member bearing an electrostatic image; two component developer including toner and permanently magnetized carrier beads, the carrier having average diameter (2a) and magnetization M b a developer transporting member having a thickness t for transporting a developer layer of the two component developer, the layer spaced close to and out of contact with the image bearing member, and wherein the developer layer is substantially without chains of carrier beads, a multipole magnet member disposed in close proximity behind the transporting member and moving relative to it so as to sweep poles across its surface, the magnet member having a periodic magnetization of spatial frequency k and a peak magnetization M 0 wherein M b , t, k, and M 0 , are chosen such that M b is sufficiently large to prevent the escape of developer, and a quantity ##EQU1## is greater than about 1/3.
Inventors
- 👤 Richard B. Lewis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 19:59
CPC Classifications
G; G03; G03G; G03G15/00; G03G15/06; G03G15/08; G03G15/09; G03G15/0921; G03G13/00; G03G13/06; G03G13/08; G03G13/09
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
137 words
Apparatus for non-interactive, dry powder development of electrostatic Images comprising: an image bearing member bearing an electrostatic image; a housing containing two component developer comprising toner and permanently magnetized carrier beads, said carrier having predefined average diameter (2a) and magnetization (M b ), a developer transporting member, disposed in said housing, having a predefined thickness (t) for transporting a developer layer of said two component developer, said layer spaced close to and out of contact with said image bearing member, and wherein said developer layer is substantially without chains of carrier beads, a multipole magnet member disposed in close proximity behind said transporting member, and moving relative to it so as to sweep poles across its surface, said magnet member having a predefined periodic magnetization of spatial frequency (k) and a predefined peak magnetization (M 0 ).
Claim 2
Dependent Claim
137 words
Apparatus for non-interactive, dry powder development of electrostatic Images comprising: an image bearing member bearing an electrostatic image; a housing containing two component developer comprising toner and permanently magnetized carrier beads, said carrier having predefined average diameter (2a) and magnetization (M b ), a developer transporting member, disposed in said housing, having a predefined thickness (t) for transporting a developer layer of said two component developer, said layer spaced close to and out of contact with said image bearing member, and wherein said developer layer is substantially without chains of carrier beads, a multipole magnet member disposed in close proximity behind said transporting member, and moving relative to it so as to sweep poles across its surface, said magnet member having a predefined periodic magnetization of spatial frequency (k) and a predefined peak magnetization (M 0 ).
Claim 3
Dependent Claim
28 words
Apparatus according to claim 1, wherein said image bearing member and said transporting member are spaced from each other less than about 0.020 inches at their closest point.
Claim 4
Dependent Claim
41 words
Apparatus according to claim 1, wherein said a, M b , t, k, and M 0 , are chosen such that M b is sufficiently large to prevent the escape of said developer, and quantity ##EQU15## is greater than about 1/3.
Claim 5
Dependent Claim
42 words
Apparatus according to claim 1, wherein said a, M b , t, k, and M 0 , are chosen such that M b is sufficiently large to prevent the escape of said developer and the quantity ##EQU16## is greater than about 1.
Claim 6
Dependent Claim
38 words
Apparatus according to claim 1, wherein said carrier comprises hard ferrite powder selected from a group consisting of barium ferrite, strontium ferrite, and combined with magnetically inert material in a volume ratio of less than 1 to 2.
Claim 7
Dependent Claim
27 words
Apparatus according to claim 1, wherein said developer transporting member is in the form of a non-magnetic cylindrical sleeve having a thickness from 0.001 to 0.008 inches.
Claim 8
Dependent Claim
21 words
Apparatus according to claim 6, wherein said sleeve is strengthened and supported over its internal area by said multipole magnet member.
Claim 9
Dependent Claim
23 words
Apparatus according to claim 6, wherein said sleeve is made by electroforming metals selected from a group consisting of nickel-phosphorous, brass, and copper.
Claim 10
Dependent Claim
25 words
Apparatus according to claim 1, wherein said multipole magnet member is comprised of a composite containing at least 60% by volume neodymium-boron-iron hard magnet alloy.
Claim 11
Dependent Claim
18 words
Apparatus according to claim 1, wherein said multipole magnet member has pole spacing between 0.5 and 2.0 millimeters.
Claim 12
Independent Claim
183 words
A method for generating a substantially condensed developer layer on a developer roll, comprising the steps of: assembling a developer magnetic assembly said magnetic assembly having a predefined periodic magnetization of spatial frequency (k) and a predefined peak magnetization (M 0 ); enclosing the developer magnetic assembly with a sleeve of a predefined thickness (t) to form said developer roll; loading said developer roll with a developer layer of two component developer comprising toner and permanently magnetized carrier beads, said carrier having predefined average diameter (2a) and magnetization (M b ) so that said developer layer is substantially without chains of carrier beads; selecting said predefined thickness (t), said predefined periodic magnetization of spatial frequency (k), said predefined peak magnetization (M 0 ,), a predefined periodic magnetization of spatial frequency (k) and a predefined peak magnetization (M 0 ,), before said assembling step to satisfy the following relationship: wherein M b , t, k, and M 0 , are chosen such that M b is sufficiently large to prevent the escape of said developer, and a quantity ##EQU17## is greater than about 1/3.
Claim 13
Independent Claim
183 words
A method for generating a substantially condensed developer layer on a developer roll, comprising the steps of: assembling a developer magnetic assembly said magnetic assembly having a predefined periodic magnetization of spatial frequency (k) and a predefined peak magnetization (M 0 ); enclosing the developer magnetic assembly with a sleeve of a predefined thickness (t) to form said developer roll; loading said developer roll with a developer layer of two component developer comprising toner and permanently magnetized carrier beads, said carrier having predefined average diameter (2a) and magnetization (M b ) so that said developer layer is substantially without chains of carrier beads; selecting said predefined thickness (t), said predefined periodic magnetization of spatial frequency (k), said predefined peak magnetization (M 0 ,), a predefined periodic magnetization of spatial frequency (k) and a predefined peak magnetization (M 0 ,), before said assembling step to satisfy the following relationship: wherein M b , t, k, and M 0 , are chosen such that M b is sufficiently large to prevent the escape of said developer, and a quantity ##EQU17## is greater than about 1/3.
Claim 14
Dependent Claim
12 words
The method of claim 11, wherein said quantity is greater than 1.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-08-30 | 2003-03-01 | 2003-08-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-08-30 | 2007-03-01 | 2007-08-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-08-30 | 2011-03-01 | 2011-08-31 | $7700.00 | Window Closed / Lapsed |