Patent ID: 8169643

Claim:
A communication system comprising: at least one user terminal connected to a network; a printer configured to perform bi-directional communications with each user terminal via the network, the printer comprising a print controlling unit that prints an image on a recording sheet based on target print data received from a user terminal, and that prints on the same recording sheet a mark set by the user terminal, from which the target print data has been received, according to a mark configuration parameter indicating configuration of the mark; a storage device; a processor; and memory storing computer executable instructions that, when executed, cause the processor to function as: a registering unit that records in the storage device a combination of a mark configuration parameter and corresponding identification data that is received from one of the at least one user terminal, the mark configuration parameter indicating configuration of a mark that has been set at the one of the at least user terminal, the identification data identifying one user that has set the mark; and a list transmitting unit that transmits to each user terminal data of a mark list that lists at least one combination of the mark configuration parameter and the corresponding identification data that has been stored in the storage device, each user terminal comprising: an inputting unit that receives user operations; a displaying unit that displays data; a user terminal processor; and user terminal memory storing computer executable instructions that, when executed, cause the user terminal processor to function as: a parameter setting unit that sets, according to input operations received via the inputting unit, a mark configuration parameter indicating configuration of a mark desired to be added to an image desired to be printed based on the target print data; a data transmitting unit that transmits a combination of the mark configuration parameter and identification data of a user that has set the mark configuration parameter to the printer via the network, the data transmitting unit transmitting target print data to the printer via the network when a printing command is received via the inputting unit; and a user data display controlling unit that displays on the displaying unit the mark list based on the data of the mark list received via the network.