Cleanup electrode

Claim 2

Apparatus for the cascade development of a latent electrostatic image supported on a moving member by the flow of two-component developer material including means to deposit two-component developer onto the moving member whereby the developer may cascade down the moving member under the influence of gravity, a development electrode positioned in closely spaced parallel relation to the moving member to define therebetween at least a portion of the development zone, said electrode extending to adjacent the uppermost region of the development zone where two-component developer material is deposited onto the moving member for its development, means to apply an electrical bias to said electrode of a polarity similar to the polarity of the latent electrostatic image and being of a magnitude greater than the charge of the latent electrostatic image supported on the moving member and means to drive the moving member through the development zone in an upward direction against the flow of the cascading twocomponent developer.

Claim 3

The apparatus of claim 1 wherein the bias applied to said electrode is of a magnitude sufficient to maintain a toner gradient in the flow of developer on the electrode side of the development zone.

Claim 4

The apparatus of claim 2 wherein he charge applied to said electrode is of a magnitude sufficient to attract developer material from the lower charged areas of the latent electrostatic image.

Claim 5

The apparatus of claim 4, wherein said electrode is positioned between 0.060 inch and 0.080 inch from the moving member and said electrode is placed at a potential between 300 and 1,000 volts greater than the potential of the latent electrostatic image being developed.

Claim 6

The apparatus as set forth in claim 1 and further including a supplemental development electrode adjacent the development zone electrically separated and physically spaced from said first mentioned development electrode so that said first mentioned development electrode is positioned between said supplemental development electrode and the location where two-component developer material is deposited onto the moving member.

Claim 7

Apparatus for use in a xerographic reproducing machine of the type wherein a latent electrostatic imagE is formed on the surface of a moving xerographic member, the member is cascade developed with two-component developer including toner and carrier and then the toner image is transferred to a support surface, the improvement comprising a first development electrode positioned in closely spaced parallel relation to the moving member to define therebetween at least a portion of a development zone, the upper edge of said first development electrode being located adjacent the uppermost portion of the cascade development zone, means to deposit two-component developer onto the moving member adjacent the uppermost portion of the cascade development zone whereby the developer may cascade down the moving member under the influence of gravity, means to apply an electrical bias to said first electrode of a polarity the same as the polarity of the latent electrostatic image, the bias on said first electrode being of a magnitude sufficient to attract toner from portions of the latent electrostatic image where development is not desired, a second development electrode positioned in closely spaced relation to the moving member to define therebetween at least another portion of the development zone, said second development electrode being electrically separated from said first development electrode and located beneath said first development electrode, means to drive the moving member through the development zone in an upward direction against the flow of the cascading two-component developer whereby a latent electrostatic image will be developed as it passes beneath said second development electrode and then said first development electrode.

Claim 8

Apparatus for use in a xerographic reproducing machine of the type wherein a latent electrostatic imagE is formed on the surface of a moving xerographic member, the member is cascade developed with two-component developer including toner and carrier and then the toner image is transferred to a support surface, the improvement comprising a first development electrode positioned in closely spaced parallel relation to the moving member to define therebetween at least a portion of a development zone, the upper edge of said first development electrode being located adjacent the uppermost portion of the cascade development zone, means to deposit two-component developer onto the moving member adjacent the uppermost portion of the cascade development zone whereby the developer may cascade down the moving member under the influence of gravity, means to apply an electrical bias to said first electrode of a polarity the same as the polarity of the latent electrostatic image, the bias on said first electrode being of a magnitude sufficient to attract toner from portions of the latent electrostatic image where development is not desired, a second development electrode positioned in closely spaced relation to the moving member to define therebetween at least another portion of the development zone, said second development electrode being electrically separated from said first development electrode and located beneath said first development electrode, means to drive the moving member through the development zone in an upward direction against the flow of the cascading two-component developer whereby a latent electrostatic image will be developed as it passes beneath said second development electrode and then said first development electrode.