AUTOMATIC TENSION APPLYING APPARATUS OF A TRANSFER BELT IN AN IMAGE FORMING APPARATUS FOR INCREASING THE LIFE SPAN OF THE TRANSFER BELT

摘要

PURPOSE: An automatic tension applying apparatus of a transfer belt in an image forming apparatus is provided to increase the life span of the transfer belt or a middle transfer unit by applying tension only when the transfer unit or the middle transfer unit performs a transfer operation. CONSTITUTION: A tension driving member having a swing shaft(125) is mounted to a transfer belt(109) and provides the transfer belt with tension in order to contact the transfer belt with a photosensitive member with a constant pressure. A tension driving canceling member is mounted to the tension driving member in order to cancel the tension to the transfer belt. A tension driving operation member(128) is mounted to a driving member for driving the transfer belt and the tension driving canceling member. The tension driving operation member operates and applies the tension to the transfer belt only when the driving member is driven.