Belt positioning structure, belt roller unit, and image forming apparatus

A belt system, comprising:

• a belt positioning structure comprising:
• an endless belt;
• and
• a belt roller around which the belt is wound, wherein
• the belt comprises a belt-side positioning component curbing position aberration from the belt roller in a roller shaft direction,
• the belt roller comprises a roller-side positioning component curbing position aberration of the belt in a belt shaft direction in cooperation with the belt-side positioning component,
• the roller-side positioning component comprises a regulation plate formed along a virtual tapered surface that has a diameter on one side in the roller shaft direction larger than a diameter on an opposite side of the regulation plate, and
• the regulation plate comprises a movement regulation component that brings the belt-side positioning component to come into contact from an outside in the roller shaft direction to regulate movement of the belt-side positioning component to the one side of the belt-side positioning component in the roller shaft direction and has a regulation shape depressed in or bulged out from the virtual tapered surface and strengthens a movement regulation force to the one side of the belt-side positioning unit in the roller shaft direction;
• and
• an image forming device configured to transfer an image formed on the endless belt to a recording medium,
• wherein the belt system is detachably mounted on a body of the image forming device,
• wherein the movement regulation component has a helical regulation shape inclined in a roller circumference direction, and
• wherein the regulation shape is a helical shape advancing to an outside in the roller shaft direction in a rotation direction when the belt is driven.

An image forming apparatus, comprising:

• an image forming device having a belt positioning structure comprising:
• an endless belt;
• and
• a belt roller around which the belt is wound, wherein
• the belt comprises a belt-side positioning component curbing position aberration from the belt roller in a roller shaft direction,
• the belt roller comprises a roller-side positioning component curbing position aberration of the belt in a belt shaft direction in cooperation with the belt-side positioning component,
• the roller-side positioning component comprises a regulation plate formed along a virtual tapered surface that has a diameter on one side in the roller shaft direction larger than a diameter on an opposite side of the regulation plate, and
• the regulation plate comprises a movement regulation component that brings the belt-side positioning component to come into contact from an outside in the roller shaft direction to regulate movement of the belt-side positioning component to the one side of the belt-side positioning component in the roller shaft direction and has a regulation shape depressed in or bulged out from the virtual tapered surface and strengthens a movement regulation force to the one side of the belt-side positioning unit in the roller shaft direction,
• wherein the image forming device transfers an image formed on the endless belt to a recording medium,
• wherein the movement regulation component has a helical regulation shape inclined in a roller circumference direction, and
• wherein the regulation shape is a helical shape advancing to an outside in the roller shaft direction in a rotation direction when the belt is driven.