IMAGE FORMING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an image forming device in which smooth sliding movement is realized and the position of an axial line can be freely changed by eliminating interference between a key and the corner part of a key groove because the position of the axial line of a conventional Oldham's coupling system driving transmission device is not freely changed because slide resistance is suddenly fluctuated up and down and the smooth sliding movement thereof is not sufficiently executed by the interference between the key and the corner part of the key groove. SOLUTION: In an Oldham's coupling 29 connecting a developing roller coupling means 27 fixed to the end part of a developing roller 11 and a main-body- side driving means 28 driving the rotation of the roller 11 and having the two-dimensional degree of freedom in a plane surface orthogonally crossed to the axial line, the outside diameter of the coupling 29 is set to be different from the outside diameters of the coupling means 27 and the driving means 28.