Image forming device

An image forming device comprising:

• an optical sensor and an ultrasound sensor disposed alongside a conveyance path of a sheet that are used to determine sheet type;
• a first conveyance guide that guides the sheet along the conveyance path;
• and
• a second conveyance guide facing the first conveyance guide across the conveyance path, wherein
• the conveyance path includes a curved portion where the first conveyance guide defines an inside of a curve of the curved portion and the second conveyance guide defines an outside of the curve of the curved portion,
• the optical sensor is disposed alongside the curved portion,
• the first conveyance guide includes a step alongside the conveyance path, disposed between the optical sensor and the ultrasound sensor in a direction of sheet conveyance, and
• after the step in the direction of sheet conveyance, the first conveyance guide is farther away from the conveyance path than before the step in the direction of sheet conveyance.