PRINTER_BACKGROUND_COLOR: specifies the background color for the actual device context, value must be a string containing the rgb information in hex format i.e. "005533".
PRINTER_SCALE: specifies the factor by which the printed output is to be scaled. the page size is scaled from the physical page size by a factor of scale/100. for example if you set the scale to 50, the output would be half of it's original size. value must be an integer.