After a skew of a sheet as a recording medium is corrected by correcting a sheet curve, exposure writing on a photosensitive drum is started synchronously with re-driving of resist rollers. When a sheet front edge is detected by a sensor, sheet conveyance is continued while adjusting a sheet conveying speed when an exposure start position reaches a transfer position at a pressure contact point between the drum and a transfer roller, thereby adjusting the time of arrival at the transfer position. A time/distance interval between the preceding and subsequent sheets are shortened, a conveying path is shortened, and the whole apparatus is miniaturized. Print processing efficiency is raised and stable printing without a variation is executed. A transfer start position of the sheet is made to accurately coincide with the exposure start position of the drum, thereby realizing a high print processing speed.