Provided are an image forming apparatus including multiple feed trays and a non-transitory recording medium. One or more hardware processors of the image forming apparatus determine, for each print product to be printed, whether the amount of sheets contained at the beginning of printing the each print product in a feed tray being used for printing, is not less than the necessary amount of sheets for printing the each print product, and cause a print engine to print the print products. In printing the print products, the one or more hardware processors, when determining that the amount of sheets in the feed tray being used for printing, determined for a next print product, which is to be printed next to a print product currently being printed, is less than the necessary amount of sheets for the next print product, cause the print engine to suspend printing the next print product.