US Patent 7311374 Liquid discharge cartridge and liquid discharge apparatus

A head cartridge has a print head which discharges ink, and an ink tank which contains ink which is supplied to the print head. A sensor which detects residual ink amount in the ink tank is provided in the ink tank. The print head includes a detection circuit which detects the presence of residual ink amount using the sensor, a judgment circuit which judges the presence of residual ink amount on the basis of an output from the detection circuit and outputs ink zero information when judging that there is no residual ink amount, and nonvolatile memory which stores ink zero information when the ink zero information is outputted from the judgment circuit.