Two component developing apparatus in a printer

A two component developing apparatus for an image forming apparatus, said apparatus comprising:

• a container,
• a developing agent conveying means for conveying a two component developing agent including toner and carrier to an image carrier from the container,
• mixing means for mixing the toner and carrier in the container,
• toner supply means for supplying the toner to the container and varying the flow of toner from a toner storage section per unit of time, the toner supplying means comprising a plurality of supply rollers which are driven independently from each other and arranged in series on a single axis,
• the plurality of supply rollers supplying different quantities of toner per unit time and comprising a plurality of first supply rollers and a plurality of second supply rollers, each of the first and second supply rollers having a number of cells or holes, whose sizes are different from each other of the toner supply rollers, the first and second supply rollers being arranged alternately on a single axis,
• control means for selectively driving the supply rollers on the basis of the detective flow of toner, so that the flow of toner per unit time from the toner storage section is controlled on the basis of a consumption rate of toner.