PURPOSE: To simply simultaneously set various parameters for processing a peripheral unit by providing setting means for setting the parameters for processing the unit by reading an output content altered by output means by image reading means.

CONSTITUTION: When updating process of a parameter is started, an image reading range of a scanner 103 is set by a scanner interface 114 to match a printing range of a parameter group, and image data is read. The read data is converted to a dot pattern from a video signal by the interface 114, stored in an input buffer 115, and a dot pattern of a set pattern is selected from the dot pattern in the buffer 115. The selected dot pattern is compared with a printing pattern of a candidate character row, a flag corresponding to the set parameter is read from a ROM 110, and an updated flag is cataloged to the NVRAM 111.