Patent attributes
Control circuit 30 determines whether or not all ink cartridges CA1 through CA6 are attached in the home position based on cartridge out signals COO. Control circuit 30 carries out communication with memory devices 21 through 26 and determines the presence or absence of communication malfunctions. When a communication malfunction develops in one of memory devices 21 through 26, control circuit 30 determines if a communication malfunction is caused by ink cartridge 30 being detached and identifies detached ink cartridge CA using identifying information. When all of ink cartridges CA1 through CA6 are attached, control circuit 30 determines which of memory devices 21 through 26 has developed a communication malfunction and identifies ink cartridge CA in which a communication malfunction has developed using identifying information.