IMAGE FORMING DEVICE

PURPOSE:To obtain a high quality image by reducing irregularities in the rotational speed of a drum-like photosensitive body in an image forming device obtaining an image in such a manner that an electrostatic latent image formed on the periphery of the drum-like photosensitive body is visualized by the sticking of toner and visualized toner image is transferred on a recording body. CONSTITUTION:A rotary inertial body 102 rotating integrally with the drum-like photosensitive body is provided and the structure of the rotational inertial body has an inertial part 102c, an attaching part 102a, and an intermediate connecting part 102b permitting elastic deformation therebetween. Thus, a vibration in a driving direction generated on a driving motor 14 and a driving force transmitting mechanism, is damped. On the other hand, the vibration of a frequency area caused by the degradation of the image is reduced within the range of 0.1-1.0kg.cm.sec of a value that the moment of the inertia of the rotary inertial body 102 is divided by gravitational acceleration.