The printer successively stores the objects contained in the PDF file as they are transmitted from the PC, and conducts the printing process for said specific page when it judges that all the objects necessary for displaying said page are stored. Also, when a memory overflow occurs, it successively prints out content objects contained in the constituent data of the PDF file stored in the RAM, while assigning identification names, and deletes the data for the content objects already printed out from the RAM so that additional constituent data of the PDF file can be received successively. It finally generates and prints out the table of contents based on the identification names of the content object and the information of the page object and the page list object. Thus, it is possible to form images directly receiving a document file such as a PDF file on a printer with a limited usable memory capacity.