Cooling device, cooling method, and image forming apparatus

A cooling method used in a cooling device, the cooling method comprising:

• contacting a heat receiver with an external hot portion;
• receiving heat by the heat receiver from the hot portion using a coolant;
• detecting a temperature in the hot portion with a temperature sensor;
• pumping a coolant from the heat receiver through a coolant circulation system to a variable-speed pump;
• switching a speed of the pump in accordance with the temperature detected by the temperature sensor;
• pumping the coolant from the pump through the coolant circulation system to the heat releaser;
• switching a speed of a variable-speed fan in the heat releaser in accordance with the temperature detected by the temperature sensor;
• cooling the coolant by the heat releaser;
• pumping the cooled coolant from the heat releaser through the coolant circulation system to the heat receiver;
• and
• releasing the heat from the hot portion to outside the cooling device using the cooled coolant.

An image forming apparatus comprising:

• a latent image carrier to carry a latent image;
• a development device to develop the latent image formed on the latent image carrier with developer, the development device being removably installed in the image forming apparatus;
• a cooling device to cool the development device,
• the cooling device comprising:
• a heat receiver to receive heat from a hot portion of the development device using a coolant while contacting the hot portion of the apparatus;
• a heat releaser to cool the heat-received coolant to release the heat from the hot portion of the development device to outside the image forming apparatus, the heat releaser having a variable-speed fan of multiple operation speed modes including an off mode;
• a coolant circulation system through which the coolant is circulated between the heat receiver and the heat releaser;
• a variable-speed pump to move the coolant through the coolant circulation system, whose operation speed modes include an off mode and relate to a coolant flow rate of the pump;
• and
• a temperature sensor to detect a temperature in the hot portion;
• and
• a controller to control the operation modes of the fan and the pump in the cooling device in accordance with the temperature detected by the temperature sensor.