In gvNix there is a printing tool for the map that is the following tag <tool:print id="ps_org_cite_pese_web_Mapa_print"/> the same works perfectly for me The issue is that when I print the image I get black and white, I would like to know if there is any possibility of get the color image.
As far as I know, gvNIX does not change anything of the color, so it gives me the impression that it must be the configuration that you have set in the printer. Checking can be as simple as printing to a PDF file or trying to print on another computer.
I just tried to print the chrome with the demo on-line and it worked perfectly for me.
Good luck!