An image forming apparatus includes an apparatus main body, a housing body, and an outer wall member. The housing includes a reflective face and a light output surface opposing the reflective face. Three bosses are arranged at three out of four positions defined between any two neighboring teeth. The ram 11 comprises the ram main body 14 capable of elevating and descending, and the striker 15 which is provided transferable in the diameter direction at the lower part of the ram main body. Spring tensioners control the wheel-to-hose pressure.