US 6,895,202 B2Granted

Non-interactive development apparatus for electrophotographic machines having electroded donor member and AC biased electrode

AssigneeXerox Corporation

InventorsJack T. LeStrange, Dan A. Hays

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Abstract

A non-interactive development system generates a toner cloud in a development zone by an AC biased stationary electrode positioned in contact with the back surface of a movable toned dielectric donor belt having a patterned electrode structure on the front surface thereof. The AC biased electrode produces AC fringe fields near the edges of the patterned electrode structure that cause the generation of a toner cloud for developing an electrostatic latent image. The donor belt is partially wrapped around a magnetic brush to produce a toner loading zone. Isolated patterned electrodes on the donor belt near the entrance region of the toner loading zone are biased to cause unloading of toner from the donor belt, while isolated electrodes near the exit region of the toner loading zone are biased to cause toner reloading of the donor belt.

Claims11

Dependent claims

A non-interactive development apparatus for use in a multicolor electrophotographic machine having a moving photoreceptor belt therein, the development apparatus being capable of developing a portion of a multicolor electrostatic latent image on a surface of said photoreceptor belt with toner without disturbance or contamination of previously developed portions of the electrostatic latent image, said development apparatus comprising:

a housing defining a chamber storing a supply of developer material comprised of carrier beads and toner;
a movable dielectric donor belt having a front and back surface with an electrode pattern being formed on said belt front surface, said belt being adjacent but spaced from the photoreceptor belt surface for conveying toner on said donor belt front surface to a development zone located in a space between said donor belt and photoreceptor belt surface;
means for supporting said donor belt for movement in an endless-path past the development zone;
means for advancing developer material from the housing chamber, said advancing means and said donor belt cooperating with one another to deposit a substantially constant quantity of toner having a substantially constant triboelectric charge onto said donor belt front surface for transporting said toner through said development zone;
a stationary electrode positioned behind and in contact with the back surface of a span of said donor belt, said stationary electrode having a dimension and location to define said development zone;
and
an AC voltage supply connected to the stationary electrode to provide an AC bias thereto, The AC voltage producing AC fringe fields at the edges of the electrode pattern on said front surface of the donor belt as said donor belt is conveyed past the stationary electrode, whereby said AC fringe fields cause detachment of the toner from the donor belt front surface and generation of a toner cloud in the development zone that develops the electrostatic latent image on the photoreceptor belt surface.

4 more elements

A non-interactive development system for a multicolor electrophotographic machine having a moving photoreceptor belt therein, the development system having a plurality of non-interactive development apparatus disposed seriatim adjacent the photoreceptor belt, one non-interactive developer apparatus being provided for each color to be used in developing a multicolor color electrostatic latent image, and each development apparatus being capable of developing a portion of the latent image on a surface of the photoreceptor surface with toner without disturbance or contamination of previously developed portions of the latent image, wherein each development apparatus of said development system comprises:

a housing defining a chamber storing a supply of developer material comprised of carrier beads and toner;
a movable dielectric donor belt having a front and back surface with an electrode pattern being formed on said belt front surface, said belt being adjacent but spaced from the photoreceptor belt surface for conveying toner on said donor belt front surface to a development zone located in a space between said donor belt and photoreceptor belt surface;
means for supporting said donor belt for movement in an endless path past the development zone;
means for advancing developer material from the housing chamber, said advancing means and said donor belt cooperating with one another to deposit a substantially constant quantity of toner having a substantially constant triboelectric charge onto said donor belt front surface for transporting said toner through said development zone;
a stationary electrode positioned behind and in contact with the back surface of a span of said donor belt, said stationary electrode having a dimension and location to define said development zone;
and
an AC voltage supply connected to the stationary electrode to provide an AC bias thereto, The AC voltage producing AC fringe fields at the edges of the electrode pattern on said front surface of the donor belt as said donor belt is conveyed past the stationary electrode, whereby said AC fringe fields cause detachment of the toner from the donor belt front surface and generation of a toner cloud in the development zone that develops the electrostatic latent image on the photoreceptor belt surface.

4 more elements

Dependencies are inferred from the claim text.