To provide an image forming apparatus capable of forming a high-accuracy pattern film even in the case of a large-size substrate, to provide a pattern film formed by the image forming apparatus, and to provide an image forming method for forming the pattern film.

A blanket 15 is composed of a belt-like rubber material, is hung over a plurality of belt support cylinders 16 and travels round between the plurality of belt support cylinders 16. An ink 8 applied on a plate 11 is transferred to the blanket 15 from the plate 11 and the ink 8 transferred to the blanket 15 is transferred to a substrate 9. A substrate entry angle rks1 to the substrate 9 of the blanket 15 is set to be 45 or less and a substrate release angle rkr1 from the substrate 9 of the blanket 15 is set to be an angle larger than the substrate entry angle rks1. Further, a plate entry angle rhs1 to the plate 11 of the blanket 15 is set to be 45 or less and a plate release angle rhr1 from the plate 11 of the blanket 15 is set to be an angle larger than the plate entry angle rhs1.