Image forming apparatus

An image forming apparatus, comprising:

• an image forming device that forms an image on a sheet;
• a plurality of feed trays each holding the sheet;
• and
• a sheet feeding device that feeds the sheet one at a time from the feed tray and feeds the sheet to the image forming device, wherein
• the plurality of feed trays include a plurality of combinations of the plurality of feed trays, the combination holding the plurality of sheets of an identical size, and the sheet of a different size is held in the feed tray of a different combination,
• in a case where an image forming instruction is input to perform image formation for a plurality of sets in each of which the image formation is performed on the plurality of sheets in which the plurality of sheets of a plurality of sizes different from each other are mixed, the sheet feeding device feeds the sheet from a predetermined feed tray to the image forming device according to the size of the sheet in the image forming instruction, and
• in a case where, in the middle of the image formation for a predetermined set in the image forming instruction, the sheet held in the predetermined feed tray runs out, and the image formation on the sheet of an identical size to that of the sheet running out is not ended, the image forming device stops image forming operation.