Patent ID: 8005411

Claim:
An image forming apparatus comprising: an image bearing member that bears a toner image; a rotatable intermediary transfer member; and a transfer unit, configured and positioned to form a transfer nip between said rotatable intermediary transfer member and said image bearing member, that transfers the toner image from said image bearing member onto a surface of said rotatable intermediary transfer member, wherein said transfer unit comprises a sheet member on which said rotatable intermediary transfer member is slidable, and comprises an elastic member that urges the sheet member toward said rotatable intermediary transfer member at a position of the transfer nip, wherein the sheet member is provided with a reinforcing portion, having a linear expansion coefficient different from that of the sheet member, in an area in which the elastic member urges the sheet member, wherein the elastic member comprises a compression deformable sponge having inner pores, and wherein at an interface where the elastic member contacts the sheet member, the compression deformable sponge has fewer pores.