US Patent 7859693 Printing system with power saving mode

In a printing system 10 connected to a host computer 20 as an upper system via a serial bus, communication control information used in a shift from a power saving mode to a normal transfer mode are previously in a response controlling portion 147 before a CPU 151 in a printing controlling portion 12 is shifted into the power saving mode, and then the response controlling portion 147 can receive the data based on the set communication control information without intervention of a CPU 151 in the cancel of the power saving mode.