A printing apparatus performs conversion processing that converts input data corresponding to a page into image data, executes a predetermined operation for transition of a printhead to a printing standby state, in a case where image data is delayed, performs holding processing that holds the image data in a data memory, and performs retaining processing until an amount of image data held in the data memory exceeds a predetermined amount. The printing apparatus also outputs the image data in the data memory in a case where the amount of image data held in the data memory exceeds the predetermined amount, and executes printhead printing based on the output image data. In a case where input data still remains, the conversion processing for the remaining input data is performed concurrently with the printing based on the output image data.