I am facing printing issues with HP OfficeJet 6500 printer. Whenever I try to print any of my documents using the black print cartridge ONLY, I don't get any print outs. I have checked all the settings and the color preset is set to gray-scale and the color option is set to black print cartridge only. In spite of all the tries that I did, I have no luck in getting black print out. I also took it with the retailer from whom I purchased this and replaced it from him since it was in the warranty but that too didn't worked. What else can be done to fix this issue?