Patent ID: 8538309

Claim:
A printing apparatus comprising: a printing section comprising: a conveyer configured for conveying a first sheet and a second sheet subsequent to the first sheet; a printer configured for printing one surface and the other surface of the first sheet, and printing one surface and the other surface of the second sheet; and a reconveyer configured for conveying the first sheet after printing the one surface of the first sheet and conveying the second sheet after printing the one surface of the second sheet, wherein the printing section is configured for performing a high-speed duplex printing where the printer prints the one surface of the first sheet, the one surface of the second sheet after the first sheet is in the reconveyer, and the other surface of the first sheet in this order; a sensor configured for determining a length of the first sheet while the conveyer conveys the first sheet and a length of the second sheet while the conveyer conveys the second sheet; a determination section configured for determining whether a pair of the first sheet and the second sheet is eligible for the high-speed duplex printing based on the combination of the length of the first sheet and the length of the second sheet after the second sheet is conveyed by the conveyer and before the second sheet is conveyed by the reconveyer; and a controller configured for controlling the printing section to convey the first sheet and the second sheet to the reconveyer when the determination section determines the pair of the length of the first sheet and the length of the second sheet is eligible for the high-speed duplex printing, and controlling the printing section to eject at least one of the first sheet and the second sheet when the determination section determines the pair of the length of the first sheet and the length of the second sheet is not eligible for the high-speed duplex printing, wherein the second sheet is ejected before being conveyed by the reconveyer when the determination section determines the pair of the length of the first sheet and the length of the second sheet is not eligible for the high-speed duplex printing, and wherein the controller is configured for controlling the printing section to continue printing on the other surface of the first sheet and to control the printing section to print contents to be printed on the one surface and the other surface of the second sheet on a third sheet, when the determination section determines the pair of the length of the first sheet and the length of the second sheet is not eligible for the high-speed duplex printing.