Patent ID: 7449861

Claim:
An electric charging apparatus for charging a secondary battery which is held in the apparatus and is attachable to a printer, the printer being driven by electric power from the secondary battery while the electric charging apparatus is attached to the printer, comprising: a communication unit configured to periodically receive an electric charging control signal from the printer to which the electric charging apparatus is attached; determination means for determining an electric charging condition for electrically charging the secondary battery and determining whether or not the electric charging control signal is received from the printer for a predetermined time period and for determining whether or not the electric charging control signal indicates permission of electric charging of the secondary battery; and control means for controlling to start electric charging of the secondary battery based on the electric charging condition determined by said determination means, in a case that said determination means determines either (i) the electric charging control signal indicates permission of electric charging of the secondary battery, or (ii) the electric charging control signal is not received from the printer for a predetermined time period.