Belt unit of electrophotographic printing apparatus

An electrophotographic printing apparatus, comprising:

• an apparatus body;
• and
• a belt unit installed in the apparatus body;
• wherein the belt unit includes:
• a belt,
• two rollers for supporting the belt so as to be substantially in parallel with each other,
• two frames for supporting the rollers and attached to opposite ends of one of the rollers respectively so as to be perpendicular to the rollers,
• two support members attached to opposite ends of the other roller so as to be perpendicular to the rollers,
• two elastic members interposed between the two support members and the two frames respectively, and
• a belt mounting guide provided between the two frames;
• and
• the belt mounting guide includes a rotating shaft disposed in parallel with the rollers, and an edge portion inclined relative to an axial direction of the rotating shaft.