A printer that includes a means (13) for storing print data of a character; a first converter (11) for converting print data to be read into a single dot pattern by performing the function of logical OR of a total of four dot patterns, assuming that a print head moving direction is a horizontal direction. The four dot patterns are: the print data, data next to such print data, data four pieces of data ahead, and data five pieces of data ahead. The printer also includes an inverter (13) for inverting the single dot pattern generated by the first converter; a second converter (14) for converting two dot patterns into a single dot pattern by performing the function of logical AND of two dot patterns. These two dot patterns are: a dot pattern newly generated by the first converter and the dot pattern inverted by the inverter, so that the number of horizontally extending data of a bold character is changed and compressed to thereby create a reduced bold character and print such reduced bold character.
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