Image forming apparatus configured to divide heating elements to be energized into a plurality of blocks and to energize the plurality of blocks at different timings

An image forming apparatus comprising:

• a thermal head comprising a plurality of heating elements arrayed in a main scanning direction, each heating element being configured to generate heat by being energized, the thermal head being configured to form an image on a printing target on the basis of print data using the plurality of heating elements while moving in a sub scanning direction relative to the printing target;
• and
• a controller configured to execute a first one-line printing process to perform printing for one line extending in the main scanning direction, the first one-line printing process comprising:
• dividing selected R heating elements into M blocks consisting of a 1-st block to an M-th block such that the M blocks include at least one high current block consisting of p heating elements of the selected R heating elements and at least one low current block consisting of q heating elements of the selected R heating elements, in which:
• R is a natural number greater than a natural number obtained by adding p to q;
• M is a natural number not less than three (3);
• p is a natural number greater than N2 and not greater than N1;
• q is a natural number not greater than N2;
• N1 is a maximum number of the heating elements that can be energized simultaneously in the plurality of heating elements;
• and
• N2 is a natural number smaller than N1;
• and
• energizing the M blocks at different timings in order of the 1-st block to the M-th block to thereby perform printing for the one line,
• wherein, in a case where the 1-st block is determined as the high current block in the dividing, at least one block of the M blocks excluding the M-th block is determined as the low current block, and
• wherein, in a case where the 1-st block is determined as the low current block in the dividing, at least one block of the M blocks excluding the M-th block is determined as the high current block.