PURPOSE: To shorten a simple wait time and to shorten the total time for conversion processing by deciding whether or not data need to be loaded from an external memory at the time of input drawing data image conversion processing, and converting drawing data which need to be loaded not immediately, but in parallel to the loading of font data as to subsequently inputted drawing data which need to be loaded.

CONSTITUTION: Three letters 'a', 'i', and 'o' (Japanese vowel) among drawing data 1 are the drawing data which need not be loaded from the external memory and two letters 'u' and 'e' are the drawing data which need to be loaded from the external memory. Then the letters which need not be loaded are converted in parallel to the conversion of the two letters which need to be loaded from the external memory and then the time spent merely to wait for the loading to ends is only the time from time t8 to time t9. Namely, the time from t6-t8 between time t6 and t9 when a loading request is made is used effectively for the conversion of the two letters 'a' and 'i'.