Printer controller, printer control method, and data storage medium for recording the controller and control method

A printer controller, printer control method, and data storage medium detect a real-time command pattern in the print data to prevent unintended real-time commands from being executed by the printer. The evaluating unit detects whether a command data stream for printing image data sent to a printer contains a specific data sequence. When the specific data sequence, such as the data sequence of a real-time command, is present in the command data stream, the generating unit generates a plurality of command data stream segments not containing the specific data sequence but producing printing image data identical to the image data of the original data stream to the printer; the sending unit then sends the plurality of command data stream segments generated by the generating unit to the printer.