Have the unit about 3 years and am about to throw it out the window (symbolically of course). Happily accept cartridges not then zickt. Must for any pressure to take out the cartridge and reinstall. Prints calibration page great and documents just as if cartridge is empty. But is 3/4 full. Takes forever, until he starts to print times. Power powerful much fuss and then comes out only scrap. Strongly discouraged.