FUSER NIP LENGTH SENSOR
Original Publication Date: 1990-Aug-31
Included in the Prior Art Database: 2004-Apr-05
Xerox Disclosure Journal
In a xerographic copying machine having a compression roll fuser, proper operation of the machine requires the accurate adjustment of the interference between the fuser roll and the backing roll. The interference between these two rolls is best determined by measurement of the fuser roll nip length, defined as, the length of the contact region between the two rolls in the direction of paper travel. Typically, this measurement has been accomplished by inserting a piece of paper in the nip for sufficient time to allow fuser oil to penetrate the paper surface and subsequently dusting the paper to obtain an impression of the nip which is representative of the nip length. This process must be iterated a number of times to enable one to accurately adjust the rolls and achieve the desired nip length. Therefore, this procedure does not facilitate the rapid adjustment of the roller nip. Alternatively, the nip length may be approximated by measurement of the deflection of the load spring used to bring the fuser roll in contact with the backup roll. However, this method suffers, like any indirect measurement, from the problems of intermediate factors, such as, variability in the load spring constants.