Image reading apparatus and image forming apparatus

An image forming apparatus comprising:

• a conveyance unit including a first driving roller and a second driving roller and configured to convey a sheet;
• an image reading unit configured to read an image on the sheet conveyed by the conveyance unit at a reading position between the first driving roller and the second driving roller in a sheet conveyance direction;
• a driving source configured to output a driving force for driving the first driving roller and the second driving roller;
• a first pulley fixed to the first driving roller;
• a second pulley fixed to the second driving roller;
• a transmission belt wound around a belt-wound-part of the first pulley and a belt-wound-part of the second pulley;
• and
• an image forming unit configured to form the image, read by the image reading unit from the sheet, on a different sheet,
• wherein an outer diameter of the belt-wound-part of the second pulley is smaller than an outer diameter of the belt-wound-part of the first pulley.