Is the "print head" part of the printer? or is it combined on the cartridge? I suspect it is the former..... and as you have already mentioned that the printer isn`t used much, it may have dried up ink on the print head...... I don`t know the Lexmark printers, so can`t help with cleaning the head, if that is the case...... If it is accessible without too much dismantling, you could perhaps try using a soft lint free cloth with some hot water and apply "damp" not "wet" to the head until it gets cold. If you do this a few times, then re-install the colour cartridge, you may be lucky !... If that is not the case, then I suggest you log into the link I gave you before fixyourprinter .... Good Luck, come back and keep us informed ! ! !.
Regards
Gerry skodadriver