on the intermediate transfer belt 22 the contacting separating mechanism moves the second transfer bias roller 221 into contact with the intermediate transfer belt 22 before formation of the full color toner image on the intermediate transfer belt 22 a recording medium passes from a cassette 223 through a feed roller 224 and a conveying roller 226 and to a standby position at a registration roller 225 when the second transfer bias roller 221 comes into contact with the intermediate transfer belt 22 the registration roller 225 is turned on so that the toner image is transferred at a prescribed position onto the recording medium the registration roller 225 feeds the recording medium to the second transfer bias roller 221 to transfer the toner image on the intermediate transfer belt 22 onto the recording medium a prescribed transfer bias is applied to the second transfer bias roller 221 after the transfer step as mentioned above the recording medium is conveyed to a fixing unit 25 the toner image is melted and fixed by a fixing roller set at a prescribed temperature thus giving a full color copy of a high resolution after image transfer from the member 21 to the belt 22 the surface of the photosensitive member 21 is cleaned by the cleaning unit 212 after image transfer from the belt 22 to the.