Patent ID: 6895202

Claim:
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.