摘要 |
In a xerographic printing system the toned copy paper is fused by the pressure nip formed by a hot roll and a backup roll. A scraping blade engages the destructible surface of the backup roll at a critical angle which is selected as a function of the coefficients of friction of the backup roll's surface and the toner/debris contamination that may be collected on the backup roll's surface. As a result, the blade slides freely on the roll's surface, but does not slide on the surface of the toner/debris contamination film. This film forms a locking angle with the blade, placing the blade in stress, and developing a film removing chisel-like action therewith. |