An engine control unit and corresponding method of controlling the engine in which the engine control unit receives a print reservation command for plural pages prior to a print request command from a printer control unit. When the engine control unit received the print reservation command for the plural pages, it is judged whether or not a sheet feed operation of recording sheets can be performed. When it is judged that the recording sheets can be fed, the recording sheets are fed and transported to a predetermined position on a transportation path with a minimum constant interval corresponding to the sheet size by sheet feed rollers or transportation rollers, then printing operation is performed according to the print request command.