Image forming apparatus and method to determine control temperatures for cooling control of inside of the image forming apparatus

A method implementable on an image forming apparatus comprising a main body housing, a first cartridge, and a second cartridge, the method comprising:

• calculating a first control temperature corresponding to the first cartridge, using an inside temperature of the main body housing and a first coefficient to be multiplied by the inside temperature;
• calculating a second control temperature corresponding to the second cartridge, using the inside temperature of the main body housing, and a second coefficient to be multiplied by the inside temperature, the second coefficient being different from the first coefficient;
• and
• performing cooling control to cool an inside of the main body housing when at least one selected from the first control temperature and the second control temperature is higher than a particular threshold.

An image forming apparatus comprising:

• a housing;
• a first cartridge;
• a second cartridge;
• a temperature sensor;
• and
• a controller configured to:
• retrieve, from the temperature sensor, an inside temperature Tin which is a temperature of air inside the housing;
• calculate a first differential temperature ΔTB-first using the inside temperature Tin and a first thermal resistance Rin-B-first, the first differential temperature ΔTB-first being a change in temperature of the first cartridge, the first thermal resistance Rin-B-first being a thermal resistance between the air inside the housing and the first cartridge;
• and
• calculate a second differential temperature ΔTB-second using the inside temperature Tin and a second thermal resistance Rin-B-second, the second differential temperature ΔTB-second being a change in temperature of the second cartridge, the second thermal resistance Rin-B-second being a thermal resistance between the air inside the housing and the second cartridge and being different from the first thermal resistance Rin-B-first.