Printing system and image forming apparatus

A printing system includes an image forming apparatus and a host terminal apparatus. The image forming apparatus is operated by a first user who picks up a printed output of the image forming apparatus. A second user sends print data from the host terminal apparatus. The image forming apparatus includes an input section, a receiving buffer, and a watermark embedding section. The first user inputs a first item of information indicative of the first user through the input section. The receiving buffer stores the print data therein. The watermark embedding section produces a watermark pattern in which information representative of the first item of information is embedded, and combines the print data with the watermark pattern. The image forming apparatus prints out the received print data with the watermark pattern embedded therein. The watermark pattern includes the first item of information therein.