CALIBRATION OF TRANSFER BLADE
Original Publication Date: 1990-Feb-28
Included in the Prior Art Database: 2004-Apr-05
Xerox Disclosure Journal
In an electrophotographic printing machine, a copy sheet contacts a toner powder image developed on a photoconductive member at the transfer station. A transfer blade presses the copy sheet into contact with the toner powder image. A solenoid is actuated each time a copy sheet passes through the the transfer area to move the blade from a non-operative position spaced from the back side of the copy sheet to an operative position contacting the back side of the copy sheet and pressing the copy sheet against the toner image on the photoconductive member. The blade is made from a flexible material such as Mylar. The timing of the blade movement must be such that the tip of the blade never contacts the toner powder image or the photoconductive member. The solenoid timing is adjusted to move the blade to the operative position after the lead edge of the copy sheet contacts the photoconductive member and to return the blade to the non-operative position before the trailing edge of the copy sheet separates from the photoconductive member. Touching the photoconductive member may result in scratches thereon, while touching the toner powder image would disturb the image and degrade copy quality. Thus, it is necessary to calibrate the timing of the solenoid moving the blade. During calibration, a service operator tapes a piece of felt backed by Mylar on to the tip of the blade. A water soluble ink is applied to the felt. Several blank copies are run. The back side of these copies will have an ink stripe showing where the ink pad made contact with the copy sheet. By observing the location of the ink stripe, the service operator can adjust the timing of the solenoid to move the blade at the desired time.