Printing apparatus

A printing apparatus for performing a printing operation, comprising:

• an image forming portion for forming a first image on a first surface of a first sheet according to first image data;
• a discharge portion for discharging the first sheet;
• a reverse transportation unit for returning the first sheet into the printing apparatus to reverse the first sheet so that the image forming portion forms a second image on a second surface of the first sheet according to second image data;
• a detection unit for detecting whether the first sheet is pulled out before the reverse transportation unit returns the first sheet;
• a sheet supply unit for transporting the first sheet to the image forming portion;
• a control unit for controlling the image forming portion to form the second image on a second sheet according to the second image data when the detection unit detects that the first sheet is pulled out,
• wherein said control unit is configured to be capable of selecting one of a first printing process and a second printing process to be performed after the detection unit detects that the first sheet is pulled out in a duplex printing operation,
• in the first printing process, said control unit is configured to control the sheet supply unit to transport the second sheet and to control the image forming portion to form the second image on one side of the second sheet when the detection unit detects that the first sheet is pulled out,
• in the second printing process, said control unit is configured to control the sheet supply unit to transport the second sheet and to control the image forming portion to form the second image on one side of the second sheet and form subsequent images including a third image and a fourth image on one sides of subsequent sheets in a single side printing operation when the detection unit detects that the first sheet is pulled out in the duplex printing operation, and
• said control unit is configured to control the image forming portion to perform the one of the first printing process and the second printing process when the detection unit detects that the first sheet is pulled out in the duplex printing operation.