US Patent 11247458 Liquid discharge apparatus

A liquid discharge apparatus includes a case receiving a cartridge, a tank, a head, and a controller to: when the cartridge is installed in the case, calculate an outflow amount Qc based on heights Hc, Hs and flow path resistances; read the amounts Vc, Vs from a memory; subtract the outflow amount Qc from the read liquid amount Vc to calculate new liquid amount Vc; add the outflow amount Qc to the read liquid amount Vs to calculate new liquid amount Vs; store the calculated liquid amounts Vc, Vs in the memory; after a time period from at the time the calculated liquid amounts Vc, Vs stored elapses, again calculate the outflow amount Qc and the liquid amounts Vc, Vs and store the calculated liquid amounts Vc, Vs in the memory.