Abstract: The printer driver receives print data from an application software program. When the received print data is font data, the printer driver transmits the font data as it is to the printer. When the print data is other than font data, but is vector data, for example, the printer driver converts the received data into bitmap data of the host-based-type format. The printer driver then transfers the converted print data to the printer. In the printer, when the received print data is bitmap data, information on the bitmap data is registered in a packet structure, and is then set in a development buffer. When the received print data is font data, on the other hand, the font data is registered In the packet structure. The font data is then developed into bitmap data, and then set over the already-set bitmap data in the development buffer. Thus, composite bitmap data is created and printed out.