In windows, set the color option to monochrome, and then try to print out the image to a color printer, the print out is not grey but colorful.

The test file is attached.

Here is the detailed information about the color printer and its driver:

 a)Name of the printer : HP690C
 b)Model : HP DeskJet 690C
 c)Color Support : Yes
 d)Port Name : LPT1
 e)Data Format : Raw
 f)DriverName : RASDD.DLL
 g)Datafile : HPDSKJET.DLL
 h)Config File : RASDDUI.DLL
 i) Driver Version : 4.01
 j)Environment : Windows NT x86