An image forming apparatus includes a memory including instructions, and at least one processor for executing the instruction to cause the image forming apparatus to act as a generation unit to perform image processing so as to generate image data including pieces of page data based on a print job, a determination unit to determine whether a piece of page data corresponding to a sheet passing a predetermined location of a conveyance path is prepared in time, and a control unit to perform, in a case where the piece of page data is not prepared in time, control to leave the sheet as a blank sheet by not performing image processing. The control unit changes a page order, determined in advance, of pages to be printed following the blank sheet in a case where it is determined the piece of page data is not prepared in time.