US5283617A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Development apparatus employing magnetic field shapers
Assignee: Xerox Corp
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Filing: 1992-09-10
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Granted: 1994-02-01
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Expires: 2012-09-10
Abstract
Abstract An electrophotographic printing machine in which an electrostatic latent image is recorded on a moving photoconductive surface by charging the appropriate areas of the surface to predetermined polarities. The latent image is a developed in a development zone with toners of a preselected color and predetermined polarity which are delivered by magnetic bead carriers. A bead removal device is provided adjacent the surface and downstream from the development zone relative to the movement of the surface. The bead removal device magnetically attracts carrier beads off the photoconductive surface. The beads are then deposited in a sump. A vacuum source is also provided for urging beads into the sump from the surface. The bead removal device comprising a sleeve mounted for rotation in a housing, adjacent the surface. The sleeve has a fixed magnet disposed proximate the surface therein and a shunt disposed generally opposite the magnet to define an attraction zone and a release zone. The vacuum source has a port proximate the release zone for drawing beads thereto and the housing can be ultimately formed to have a large aperture or relatively small aperture to urge beads on and near the photoconductive surface to the small aperture.
Inventors
- 👤 Lawrence R. Benedict
- 👤 Gary A. Denton
- 👤 Francisco Zirilli
- 👤 Jorge A. Alvarez
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:57
CPC Classifications
C; C07; C07C; C07C57/00; C07C57/46; C07C57/50; C07D; C07D307/00; C07D307/77; C07D307/78; C07D307/82; C07D307/83; C07D311/00; C07D311/02; C07D311/04; C07D311/22; C07D311/24; C07D311/76; C07D405/00; C07D405/02; C07D405/12; C07D407/00; C07D407/02; C07D407/12
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
115 words
An apparatus for developing a latent image recorded on a moving photoconductive surface to form a developed image on the photoconductive surface for transfer to a sheet at a transfer station comprising: magnetic means, generating a magnetic field, for attracting and moving magnetic carrier beads having toner particles adhering triboelectrically thereto to a development zone proximate to the photoconductive surface so that the latent image attracts toner particles from the carrier beads thereto; magnetic pick off means, positioned adjacent the photoconductive surface intermediate the transfer station and the development zone for removing magnetic carrier beads adhering to the photoconductive surface; and vacuum means for removing magnetic carrier beads adhering to said magnetic pick off means.
Claim 2
Independent Claim
115 words
An apparatus for developing a latent image recorded on a moving photoconductive surface to form a developed image on the photoconductive surface for transfer to a sheet at a transfer station comprising: magnetic means, generating a magnetic field, for attracting and moving magnetic carrier beads having toner particles adhering triboelectrically thereto to a development zone proximate to the photoconductive surface so that the latent image attracts toner particles from the carrier beads thereto; magnetic pick off means, positioned adjacent the photoconductive surface intermediate the transfer station and the development zone for removing magnetic carrier beads adhering to the photoconductive surface; and vacuum means for removing magnetic carrier beads adhering to said magnetic pick off means.
Claim 3
Dependent Claim
67 words
The apparatus of claim 1, wherein said magnetic pick off means includes a rotatably mounted non-magnetic tubular member, means for rotating said tubular member and a magnetic unit disposed stationarily, within said tubular member for generating a second magnetic field which defines a pick off area on said tubular member so that the bead carriers are attracted and adhere to said tubular member in the pickup area.
Claim 4
Dependent Claim
47 words
The apparatus of claim 2, wherein said magnetic pick off means further includes a shunt for minimizing the magnetic field generated by said magnetic unit to define a release area on said tubular member so that the bead carriers adhering to said tubular member are released therefrom.
Claim 5
Dependent Claim
39 words
The apparatus of claim 3, further comprising a housing having at least said magnetic pick off means disposed therein, said housing defining an input port adjacent the release area with said vacuum means being coupled to the input port.
Claim 6
Dependent Claim
32 words
The apparatus of claim 4, wherein said shunt is mounted stationarily within said tubular member and is positioned substantially between said magnetic unit and the release area defined on said tubular member.
Claim 7
Dependent Claim
14 words
The apparatus of claim 5, wherein said shunt comprises a strip of ferromagnetic material.
Claim 8
Dependent Claim
32 words
The apparatus of claim 4, wherein said housing defines an aperture adjacent the photoconductive surface so that beads attracted to said magnetic pick off means enter said housing through the aperture therein.
Claim 9
Dependent Claim
38 words
The apparatus of claim 7, wherein the aperture in said housing comprises a venturi nozzle so that the flow generated by said vacuum means between said housing and the photoconductive surface urges bead carriers therebetween toward said nozzle.
Claim 10
Independent Claim
133 words
A method for developing a latent image recorded on a moving photoconductive surface to form a developed image on the photoconductive surface for transfer to a sheet at a transfer station, comprising the steps of: generating a magnetic field for attracting magnetic carrier beads having toner particles adhering triboelectrically thereto, and moving the magnetic carrier beads and toner particles to a development zone proximate to the photoconductive surface so that the latent image attracts toner particles from the carrier beads thereto; generating a second magnetic field with a magnetic pick off device positioned adjacent the photoconductive surface intermediate the transfer station and the development zone for removing magnetic carrier beads adhering to the photoconductive surface; and generating an aeriform fluid flow to remove magnetic carrier beads adhering to the magnetic pick off means.
Claim 11
Independent Claim
133 words
A method for developing a latent image recorded on a moving photoconductive surface to form a developed image on the photoconductive surface for transfer to a sheet at a transfer station, comprising the steps of: generating a magnetic field for attracting magnetic carrier beads having toner particles adhering triboelectrically thereto, and moving the magnetic carrier beads and toner particles to a development zone proximate to the photoconductive surface so that the latent image attracts toner particles from the carrier beads thereto; generating a second magnetic field with a magnetic pick off device positioned adjacent the photoconductive surface intermediate the transfer station and the development zone for removing magnetic carrier beads adhering to the photoconductive surface; and generating an aeriform fluid flow to remove magnetic carrier beads adhering to the magnetic pick off means.
Claim 12
Dependent Claim
38 words
The method of claim 9, further comprising the step of electrically biasing the magnetic pick off device to attract toner thereto, wherein said step of generating the aeriform fluid comprises removing toner from the magnetic pick off device.
Claim 13
Dependent Claim
31 words
The method of claim 10, wherein the step of generating the aeriform fluid flow includes moving bead carriers, on or adjacent the magnetic pick off device to a location remote therefrom.
Claim 14
Independent Claim
206 words
An apparatus for removing magnetic carrier beads from a developed image formed on a moving photoconductive surface at a developing zone and adapted to be transferred to a sheet at a transfer station, comprising: a first magnetic bead pick off device positioned proximate a downstream portion of the developing zone in the direction of movement of the photoconductive surface for removing magnetic carrier beads adhering to the photoconductive surface; a second magnetic bead pick off device intermediate said first bead pick off device and the transfer station; an air flow generator for generating an air flow from the photoconductive surface toward said second magnetic bead pick off such that contaminants proximate the photoconductive surface are attracted to said second magnetic bead pick off device; and a rotating sleeve for supporting said second magnetic bead pick off device therein, said sleeve and the photoconductive surface defining a nip area therebetween; and a housing for supporting and confining said sleeve, said housing defining an aperture in the nip area such that said air flow generator generates an air flow from outside said housing into said housing through the aperture therein such that the air flow and said second magnet attract contaminants proximate the photoconductive surface into said housing.
Claim 15
Independent Claim
206 words
An apparatus for removing magnetic carrier beads from a developed image formed on a moving photoconductive surface at a developing zone and adapted to be transferred to a sheet at a transfer station, comprising: a first magnetic bead pick off device positioned proximate a downstream portion of the developing zone in the direction of movement of the photoconductive surface for removing magnetic carrier beads adhering to the photoconductive surface; a second magnetic bead pick off device intermediate said first bead pick off device and the transfer station; an air flow generator for generating an air flow from the photoconductive surface toward said second magnetic bead pick off such that contaminants proximate the photoconductive surface are attracted to said second magnetic bead pick off device; and a rotating sleeve for supporting said second magnetic bead pick off device therein, said sleeve and the photoconductive surface defining a nip area therebetween; and a housing for supporting and confining said sleeve, said housing defining an aperture in the nip area such that said air flow generator generates an air flow from outside said housing into said housing through the aperture therein such that the air flow and said second magnet attract contaminants proximate the photoconductive surface into said housing.
Claim 16
Dependent Claim
46 words
The apparatus of claim 12 wherein said housing is spaced from the photoconductive surface so that the aperture therein provides an air flow controlling nozzle such that said air flow generator produces a high velocity air flow about said sleeve to remove contaminants from said sleeve.
Claim 17
Dependent Claim
46 words
The apparatus of claim 13 further comprising magnetic field shapers disposed proximate said first magnetic bead pick off device and said second magnetic pick off device to enhance release of magnetic bead carriers from said first magnetic pick off and said second magnetic pick off devices.
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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) | 1997-01-31 | 1997-08-02 | 1998-02-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-01-31 | 2001-08-02 | 2002-02-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-01-31 | 2005-08-02 | 2006-02-01 | $7700.00 | Window Closed / Lapsed |