Fuji Xerox Docucentre 3370

Hi everyone, my wife and I are new in digital printing business, I just want to ask if there is a technique on how to print a solid look color in glossy paper (250gsm).

Printing in full bleed black color is no problem but going in a lighter shade, brown for example, produces dull output, you can see the shade of white in the print out, is there a way to improve that in the settings? we use photoshop for the program.

thank you very much