Image generating apparatus

An image generating apparatus comprising:

• a thermal head for printing a print image;
• an apparatus body storing said thermal head;
• a first temperature sensor for detecting the temperature of said thermal head;
• a second temperature sensor for detecting an ambient temperature indicating the temperature of the atmosphere in said apparatus body;
• a previously created first table defining the relation between data quantities and a predicted ambient temperature in said apparatus body;
• a second table defining the relation between a corrected temperature of said thermal head and the heat quantity supplied to said thermal head;
• and
• a control portion printing said print image by predicting an ambient temperature in said apparatus body substantially reaching a constant level after continuously printing the same printing image as said print image from a data quantity of said print image and adding a heat quantity corresponding to the difference between predicted said ambient temperature in said apparatus body and printing-time ambient temperature in said apparatus body detected by said second temperature sensor and a printing-time temperature of said thermal head detected by said first temperature sensor to a heat quantity of said thermal head, wherein
• said control portion is so formed as to predict said ambient temperature in said apparatus body substantially reaching said constant level after continuous printing from the data quantity of said print image on the basis of said first table,
• for deciding the heat quantity supplied to said thermal head through said second table with a corrected temperature calculated by subtracting the difference between said predicted ambient temperature in said apparatus body and said printing-time ambient temperature in said apparatus body detected by said second temperature sensor from the temperature of said thermal head detected by said first temperature sensor,
• said first table and said second table are individually provided for the respective ones of three primary colors of object color, and
• said first table is created by measuring said ambient temperature in said apparatus body every print number when continuously printing each of print images of different data quantities on a plurality of papers thereby deciding said ambient temperature in said apparatus body substantially reaching said constant level after continuous printing on a plurality of papers, thereafter plotting the relation between each said data quantity and said ambient temperature in said apparatus body substantially reaching said constant level after continuous printing every said data quantity, calculating a first relational expression of an approximate line on the basis of plotted points and defining the relation between each said data quantity and said predicted ambient temperature in said apparatus body from the first relational expression of said approximate line.