so that the conveyance side surface 171 a is movable below the image formation units 100 y 100 m 100 c and 100 k along their arrangement the belt cleaner 175 is disposed under the sheet conveyor belt 171 that is stretched below the transfer rollers 172 the belt cleaner 175 is configured to clean the conveyance side surface 171 a of the sheet conveyor belt 171 facing the image formation units 100 y 100 m 100 c and 100 k in the width direction a fixing portion 180 is disposed inside the main body 110 and downstream of the transfer portion 170 in the sheet feeding direction the fixing portion 180 is configured to fix the toner image formed onto the sheet p the fixing portion 180 includes a heat roller 181 and a pressure roller 182 the heat roller 181 includes a roller body made of a metal thin tube whose surface is mold free and a halogen lamp set inside the roller body the heat roller 181 is configured to rotate in a direction of an arrow in fig1 via the power transmission mechanism provided in the main body 110 the pressure roller 182 can be a silicone rubber roller disposed to press against the heat.