Printing apparatus, control method of printing apparatus, and storage medium

An image forming apparatus comprising:

• a printing unit configured to print image data on a sheet;
• a sheet feeding unit configured to feed the sheet from a sheet storage unit to the printing unit;
• a sheet re-feeding unit configured to be operable when two-sided printing is to be performed, to re-feed the sheet, printed on a front side of the sheet, toward the printing unit so as to print another image data on a back side of the sheet;
• a receiving unit configured to receive a print job for printing a first page of image data on a front side of a first sheet, printing a second page of image data on a front side of a second sheet, and printing a third page of image data on a back side of the second sheet;
• and
• a control unit configured to:
• specify a type of sheets that are to be used for the first and second sheets,
• control, in a case where the type of sheets is specified as pre-numbered sheets, the printing unit to print on the first and second sheets in the following order:
• firstly, the first page of image data is printed on the front side of the first sheet fed by the sheet feeding unit,
• secondly, the second page of image data is printed on the front side of the second sheet fed by the sheet feeding unit, and
• thirdly, the third page of image data is printed on the back side of the second sheet re-fed by the re-feeding unit, and
• control, in a case where the type of sheets is not specified as pre-numbered sheets, the printing unit to print on the first and second sheets in the following order:
• firstly, the second page of image data is printed on the front side of the second sheet fed by the sheet feeding unit,
• secondly, the first page of image data is printed on the front side of the first sheet fed by the sheet feeding unit, the first sheet being not re-fed by the re-feeding unit, and
• thirdly, the third page of image data is printed on the back side of the second sheet re-fed by the re-feeding unit.