PRINTER

PURPOSE:To eliminate interruption of printing without inviting any cost increase in a normal case by providing a buffer memory which stores output data for printing and storing alphabet pattern data into a font memory between lines of characters which are output for printing. CONSTITUTION:Command data converted to physical character code is stored in a page buffer 4 and if printing data equivalent to more than one page is stored, an address is given to a font memory 5 and a corresponding character pattern is read out. This pattern is stored into a line bit buffer 6 and the content is read out to follow the carrying of paper, and then is transmitted to a printer. At that time, a control CPU 9 monitors data amount, which is not yet output, of the printer in the line bit buffer 6. A character pattern is not written into the buffer 6, and if conditions under which printing operation can be continued for a prearranged time, writing of character pattern data into the buffer 6 is interrupted and an alphabet pattern is written into the font memory 5 utilizing the interruption time without interruption of printing.