Drive force transmission mechanism, image forming apparatus and belt manufacturing method
A drive force transmission mechanism includes a drive pulley, a driven pulley and an endless belt. The endless belt is wound around the drive pulley and the driven pulley and transmits a rotation of the drive pulley to the driven pulley. At least one of the drive pulley and the driven pulley has a protruding part protruding outwardly in a radial direction around an outer circumferential face of the drive pulley or the driven pulley. The belt is a nonmagnetic metal belt having an outer circumferential face and an inner circumferential face. The outer circumferential face has a surface roughness smaller than a surface roughness of the inner circumferential face.
1. A drive force transmission mechanism comprising:
a drive pulley;
a driven pulley; and
an endless belt wound around the drive pulley and the driven pulley and transmitting a rotation of the drive pulley to the driven pulley,
wherein at least one of the drive pulley and the driven pulley has a protruding part protruding outwardly in a radial direction around an outer circumferential face of the drive pulley or the driven pulley, and
the belt is a nonmagnetic metal belt having an outer circumferential face and an inner circumferential face, in which the outer circumferential face has a surface roughness smaller than a surface roughness of the inner circumferential face and is a mirror face having an average surface roughness Ra of 0.1 μm or smaller.
2. The drive force transmission mechanism according to claim 1 ,
wherein the inner circumferential face of the belt has an average surface roughness Ra of 0.3 μm or smaller.
3. The drive force transmission mechanism according to claim 1 ,
wherein the belt has a Vickers hardness of 490 Hv or larger.
4. The drive force transmission mechanism according to claim 1 ,
wherein the belt has a tensile strength of 1500 MPa or larger.
5. The drive force transmission mechanism according to claim 1 ,
wherein the drive pulley or the driven pulley has a diameter of 8 mm or larger.
6. The drive force transmission mechanism according to claim 1 ,
wherein the driven pulley has a diameter larger than a diameter of the drive pulley, and
the protruding part is formed around the outer circumferential face of the driven pulley.
7. The drive force transmission mechanism according to claim 1 ,
wherein the protruding part has a crown shape where a center portion in a thickness direction of the drive pulley or the driven pulley is protruded more outwardly than end portions in the thickness direction.
8. An image forming apparatus comprising a photosensitive drum to be rotated by the drive force transmission mechanism according to claim 1 .