PURPOSE: To enable printing of a reverse character, a bordered character and a boldface character by printing at least either the bordered character or the boldface character through a combination of character patterns generated by each character pattern generator.

CONSTITUTION: When data written into a receiving buffer 1 is printing data, a character pattern based on data is referred to by a reference character pattern generator 2 or a reverse character pattern generator 3, and is passed to a pattern control 4. If data for a single line is ready, a pattern control 4 starts a printing control 7. The printing control 7 prints, referring to a pattern buffer 5 and a color information buffer 6. Further, a command for overlapping of characters is set in a printer, and the pattern control 4 develops a character pattern over the previous pattern which has been spread in the pattern buffer 5, Consequently information is set in a color information buffer 6 by the pattern control 4. A pattern is constituted in accordance with a character overlapping command, and either the bordered character or boldface character is printed according to color information.