i have hp 690c printer my color cadridge is empty for past 1 months even it still print black printouts. but when i give any printouts the orange led (for paper and cadridge problem) glows continuesly. i tried to remove and intall both cadridge but it glows continuesly. i cant even take any printer test page. but my friend said that his hp printer is working without color cadridge for past 6 months. is color cadridge is nedd for printer.