In fixing process of an image forming apparatus such as a printer fuser unit, the toner is fixed to a paper by heat and pressure. The printer fuser unit comprises a fixing sleeve, a heat source, a pressure roller including an elastic layer, and a pad. When a paper with toner passes through between the sleeve and the pressure roller, the toners are fused and fixed to the paper. The sleeve rotates following the pressure roller driven by a motor and is pressed against the roller through the pad in order to form a nip area which means a distributed contact area between the sleeve and the roller. The pad and the inner surface of the sleeve are in sliding contact via a sliding sheet impregnated with a lubricant. In some operational conditions, uncomfortable noise can occur by friction between the sleeve and the sliding sheet attached to the pad. The purpose of this study is to clarify the generation mechanism of friction-induced vibration and propose countermeasures against noise based on generation mechanism of friction-induced vibration. The present study investigates the relationship between the tendency of noise occurring and friction characteristics of the sliding part, the effect of the rotational direction on noise, and the actual operating vibration of the fixing sleeve and the pressure roller during noise generation. As a result, we identified that friction-induced vibration is caused by dry friction. Furthermore, we estimated the main vibration source by measuring the actual vibration of each member and the effect of damping. We also identified factors that affect the noise frequency. Finally, we proposed countermeasures against noise based on the generation mechanism of frictioninduced vibration generated in the printer fuser unit.