PURPOSE: To enhance printing speed and obtain favorable printing quality by providing a rule data coupling means for judging whether rule data stored in a first temporary storage means and rule data stored in a second temporary storage means accord with each other, coupling both of the data to form data representing one rule when both of the data accord with each other, and for storing the coupled data in an organized rule data storage means.

CONSTITUTION: A rule data coupling means 14 checks whether data stored in a temporary storage means 12 and data stored in a temporary storage means 6 accord with each other. When both of the data accord with each other, they are coupled to form data representing one rule. The rule data before the coupling are deleted from an organized rule data storage means 8, and the coupled new rule data is stored into the means 8. When other organized rule data are already stored in the storage means 8, the coupled new rule data is checked for accordance thereof with the other organized rule data, before being stored into the means 8. When the coupled new rule data does not accord with any of the other organized rule data, the new rule data is stored as it is into the storage means 8. When the new rule data accords with one piece of the other organized rule data, they are coupled to form a single piece of data, which is stored into the storage means 8. Thereafter, a composition data calculating means 16 calculates and outputs composition data, based on the organized rule data thus obtained.