Intermediate transfer belt and image forming apparatus
An intermediate transfer belt used for an image forming apparatus of an electrophotographic system includes: an elastic layer; and a surface layer formed on the elastic layer, wherein stress relief time τ [ms] of a material used for the elastic layer and hardness H [MPa] of the surface layer satisfy a first condition that 0.48<τ<0.75 and 50<H<6275τ 3 −13820τ 2 +10140τ−2330 or a second condition that 0.75≦τ and 50<H<150.
1. An intermediate transfer belt used for an image forming apparatus of an electrophotographic system, the intermediate transfer belt comprising:
an elastic layer; and
a surface layer formed on the elastic layer, wherein
stress relief time τ [ms] of a material used for the elastic layer and hardness H [MPa] of the surface layer satisfy
a first condition that 0.48<τ<0.75 and 50<H<6275τ 3 −13820τ 2 +10140τ−2330 or a second condition that 0.75≦τ and 50<H<150.
2. The intermediate transfer belt according to claim 1 , wherein
the stress relief time τ and the hardness H satisfy
a third condition that 0.5≦τ≦0.75 and 60≦H≦5333τ 3 −12000τ 2 +8987τ−2100 or a fourth condition that 0.75≦τ and 60≦H≦140.
3. The intermediate transfer belt according to claim 2 , wherein
the stress relief time τ and the hardness H satisfy
a fifth condition that 0.6≦τ≦0.85 and 70≦H≦120.
4. The intermediate transfer belt according to claim 1 , wherein the material used for the elastic layer contains a thermally crosslinking rubber material.
5. The intermediate transfer belt according to claim 1 , wherein material used for the surface layer is such that surface-treated metal oxide fine particles are contained in a cured resin obtained by curing an active energy ray-curable composition containing polyfunctional (metha)acrylate, polyurethane acrylate, and a polymerizable compound having a low surface energy group.
6. The intermediate transfer belt according to claim 5 , wherein the polymerizable compound having a low surface energy group is a fluorine-denatured (metha)acrylate.
7. The intermediate transfer belt according to claim 5 , wherein the polyurethane acrylate has a number average molecular weight of 10000 or more, a stretch rate of 250% or more, and a tensile strength of 200 kgf/cm2 or more.
8. An image forming apparatus comprising:
an image holding body that holds a toner image;
the movable intermediate transfer belt according to claim 1 ;
a primary transfer portion that performs primary transfer of the toner image held on the image holding body onto a surface layer of the intermediate transfer belt; and
a secondary transfer portion that performs secondary transfer of the toner image transferred onto the intermediate transfer belt, onto a transfer material.