Patent ID: 7983599

Claim:
An automatic belt tension apparatus for use in an image forming device including at least one belt, and a driving unit supporting the belt and driving the belt to rotate, the automatic belt tension apparatus comprising: a tension actuating part connected to the driving unit and operated by a driving force of the driving unit; a tension applying part coupled to the tension actuating part, the tension applying part to selectively apply a predetermined tension to the belt when the driving force is a predetermined range, installed with respect to the belt; a tension clutch to connect the tension actuating part and the tension applying part, the tension clutch including a clutch spring to generate a sliding friction force, so that the driving force of the tension actuating part is transmitted to the tension applying part only when the driving force is within the predetermined range; and a tension releasing part to operate the tension applying part to not apply the predetermined tension to the belt, installed with respect to the tension applying part.