Image forming apparatus and control method thereof

An image forming apparatus comprising:

• a developer supply unit which supplies a toner;
• an image forming unit which comprises a developing unit accommodating therein a two-component developer having a toner supplied by the developer supply unit and a carrier mixed, and comprising a mixer mixing the two-component developer and a mixing driver driving the mixer, and forms an image according to a print command;
• a storage unit which stores therein a table storing in advance a value of a first parameter for a timing of starting a mixing of the developer corresponding to an average toner consumption volume;
• and
• a controller which calculates an average toner consumption volume of the image at a preset first interval, determines a value of the first parameter according to the calculated average toner consumption volume by using the table, determines whether to mix the developer by using the determined value of the first parameter and controls the image forming unit to suspend the print operation according to a determination result and controls the mixing driver to mix the two-component developer accommodated in the developing unit.