US Patent 7370930 Non-contact communication between device and cartridge containing consumable component

The ink unit of a printer has a memory circuit (memory element) for non-contact communication. The memory circuit has a hold mode M2 in which memory access commands from the transmitter/receiver are not received, and an active mode M4 in which memory access is permitted upon receipt of a memory access command. The memory circuit shifts into active mode M4 if the ID contained in the active mode command matches its own ID when an active mode command containing the cartridge ID is received from the transmitter/receiver while in hold mode M2. The reception of an anti-collision start command from the transmitter/receiver while in hold mode M2 results in a shift to anti-collision mode M3 to check the ID.