BIASED MEMBER TO PREVENT CONTAMINATION
A method for preventing contamination of a lens assembly by charged particles on an image bearing surface in an electrophotographic printer includes providing a conductive electrode with an opening adjacent the lens assembly; charging the conductive electrode with a variable voltage power supply; and matching a voltage on the image bearing surface with the variable voltage power supply.
1 . A method for preventing contamination of a lens assembly by charged particles on an image bearing surface in an electrophotographic printer comprising:
providing a conductive electrode with an opening adjacent the lens assembly, wherein said conductive electrode is provided upstream and downstream of the lens assembly with respect to a direction of movement of the image bearing surface;
charging the conductive electrode with a variable voltage power supply; and
matching a voltage on the image bearing surface with the variable voltage power supply so as to reduce an attractive force between the image bearing surface and the conductive electrode.
2 . The method of claim 1 , wherein the conductive electrode is attached to a dielectric layer and the dielectric layer is attached to a housing of the lens assembly.
3 . The method of claim 2 , wherein the conductive electrode is made of a metallic material.
4 . The method of claim 1 , wherein the variable voltage power supply is the same power supply used to energize a corona charger grid in the electrophotographic printer.
5 . The method of claim 1 , wherein the image bearing surface is a photoreceptor used to create a latent image and the surface of the photoreceptor is charged to a voltage level by a corona charger.
6 . The method of claim 5 , wherein the voltage level of the surface of the photoreceptor matches a voltage level applied to the corona charger grid by a corona charger grid power supply.
7 . An exposure subsystem for an electrophotographic printer comprising:
an LED array for forming an image on an image bearing surface;
a lens assembly for focusing the LED array on the image bearing surface;
a conductive electrode with an opening adjacent the lens assembly, wherein said conductive electrode is provided upstream and downstream of the lens assembly with respect to a direction of movement of the image bearing surface;
wherein the conductive electrode is charged with a variable voltage power supply; and
wherein a voltage on the variable voltage power supply matches a voltage on the image bearing surface, so as to reduce an attractive force between the image bearing surface and the conductive electrode.