# US 6,295,431 B1 · Apparatus for non-interactive electrophotographic development

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- Number: US 6,295,431 B1
- Document ID: US6295431B1
- Status: Granted
- Kind: B1
- Application number: 09/439,123
- Filed: 1999-11-12
- Granted: 2001-09-25
- Earliest claimed: 1999-11-12
- Assignees: Xerox Corporation
- Inventors: Dale R. Mashtare; Christopher Snelling
- Web page: https://patentgrep.com/patent/US6295431B1

## CPC

- G03G 15/0803: {in a powder cloud}
- G03G 2215/0621: powder cloud
- G03G 2215/0643: Electrodes in developing area, e.g. wires, not belonging to the main donor part
- G03G: ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY

## Abstract

An apparatus for non-interactive, dry powder development of electrostatic Images composed of solid areas and fine lines areas on an imageable surface including a housing containing developer material; a magnetic member, spaced a predefined distance from the image, for transporting the developer material from the housing to develop solid areas of the image, the magnetic roll including an magnetic core and a cylindrical sleeve enclosing and rotating about the magnetic core; and a donor member, adjacent to the magnetic roll and spaced from the image receiving member and adapted to transport marking particles to a development zone adjacent the image receiving member; an electrode positioned in the development zone between the image receiving member and the donor member; a voltage supply for electrically biasing the electrode during a developing operation with an alternating current to detach marking particles from said donor member, forming a cloud of marking particles in the development zone, and developing fine line areas of the image from the cloud.

## Claims

### Claim 1

Apparatus for non-interactive, dry powder development of electrostatic images composed of solid areas and fine line areas on an imageable surface with developer material comprising:
a housing containing developer material;
a magnetic member, spaced a predefined distance from said images, for transporting said developer material from said housing to develop solid areas of said images, said magnetic member including a magnetic core and a cylindrical sleeve enclosing and rotating about said magnetic core;
a donor member, adjacent to said magnetic member and spaced from the imageable surface and adapted to transport developer material to a development zone adjacent the imageable surface said magnetic member loads said donor member with developer material;
an electrode positioned in the development zone between the imageable surface and the donor member; and
a voltage supply for electrically biasing said electrode during a developing operation with an alternating current to detach developer material from said donor member, forming a cloud of developer material in the development zone, and developing fine line areas of said images from the cloud.

### Claim 2

Apparatus for non-interactive, dry powder development of electrostatic images composed of solid areas and fine line areas on an imageable surface with developer material comprising:
a housing containing developer material;
a magnetic member, spaced a predefined distance from said images, for transporting said developer material from said housing to develop solid areas of said images, said magnetic member including a magnetic core and a cylindrical sleeve enclosing and rotating about said magnetic core; means for biasing said magnetic member with a DC and AC bias;
a donor member, adjacent to said magnetic member and spaced from the imageable surface and adapted to transport developer material to a development zone adjacent the imageable surface;
an electrode positioned in the development zone between the imageable surface and the donor member; and
a voltage supply for electrically biasing said electrode during a developing operation with an alternating current to detach developer material from said donor member, forming a cloud of developer material in the development zone, and developing fine line areas of said images from the cloud.

### Claim 3 (depends on 2)

The apparatus according to claim 2, wherein said DC applied is to said magnetic member to insure background regions of the images are not developed.

### Claim 4 (depends on 2)

The apparatus according to claim 2, wherein said predefined distance is between 0.020″ and 0.050″.

### Claim 5 (depends on 2)

The apparatus of claim 2, wherein said magnetic member has a developer material bed height of 0.015″ and 0.045″.

### Claim 6 (depends on 5)

The apparatus of claim 5, further comprising means for adjusting developer material bed height on said magnetic member.

### Claim 7 (depends on 6)

The apparatus of claim 6, wherein said adjusting means includes a trim blade.

### Claim 8 (depends on 2)

The apparatus of claim 2, wherein said biasing means for said magnetic member has a frequency between 1 Khz and 4 KHz.