Sponge roller, method of manufacturing sponge roller and image forming apparatus

摘要

PROBLEM TO BE SOLVED: To provide a sponge roller which has high durability, excellent surface flatness and small permanent compressive strain and to provide a manufacturing method for the sponge roller and an image formation device equipped with the sponge roller.SOLUTION: A sponge roller has a shaft body and an elastic layer on an outer peripheral surface of the shaft body. The elastic layer is made of millable type silicone rubber, unexpanded micro balloons and a chemical foaming agent. In a cross-section of the elastic layer, a cell area ratio between the unexpanded micro balloons and the chemical foaming agent ranges from 95:5 to 50:50. In a manufacturing method of the sponge roller, a mixture is prepared by mixing millable type silicone rubber, the unexpanded micro balloons, the chemical foaming agent and a cross-linker. The mixture is then subjected to extrusion molding for molding the mixture on the outer peripheral surface of the shaft body, and heat hardening. An image formation device is provided.SELECTED DRAWING: Figure 1