A printer driver is a dynamic-link library (DLL) that consists of a set of graph-ics functions for a particular printer device. These graphics functions translate device-independent graphics commands into a stream of device-dependent commands and data. A printer driver receives the graphics commands from the graphics-device interface (GDI) portion of Windows and sends device commands either directly or indirectly to the printer.
Each printer driver supports a specific printer technology. Printer technologies
include raster devices (for example, dot-matrix printers) and vector devices (for
example, plotters), and devices with higher-level languages, such as PostScript page-description language (PDL). However, a printer driver can support any number of models and manufacturers as long as the printers share the same basic technology.
Unlike most Windows device drivers, a printer driver is generally not responsible for hardware communication with the printer. Instead, the driver uses existing Windows functions to open and write to a printing queue, to a file on disk, or directly to the printer through a communications port.