Drive for belt

An image forming apparatus comprising:

• a belt driving device,
• wherein the belt driving device includes:
• an endless belt;
• a stretch roller to engage with the endless belt, the stretch roller including a rotary shaft;
• a steering roller that is spaced apart from the stretch roller on an inner side of the endless belt;
• an adjustment member that is disposed along the rotary shaft of the stretch roller, the adjustment member to move along the rotary shaft;
• and
• a linking mechanism that connects the adjustment member and the steering roller, the linking mechanism to engage with a contact surface of the adjustment member, and
• wherein the contact surface is provided with contact points that are positioned at different distances from the rotary shaft such that, during movement of the adjustment member, the linking mechanism is lifted, and the steering roller tilts so as to maintain a disposition of the endless belt relative to the steering roller.