Nip width of an on-demand fuser : Part II. Longitudinal model

This paper examines bending of the pressure roller and heating element in an on-demand fuser, a circumstance that leads to variation in distributed load along the length of the roller. These bending effects are coupled with the deformation of the rubber coating on the pressure roller and lead to a variation in nip width along the length of the fuser. A longitudinal model has been developed using the Rayleigh-Ritz method and a cross-section model described in a companion paper. This model predicts local nip width, centerline deflection of the pressure roller, compression of the rubber layer, and deflection of the heater element. This model can be applied in designing a crowned pressure roller and/or heater element that will ensure a constant nip width.