Patent ID: 7778556

Claim:
A toner supply device comprising: a toner container filled with toner, wherein the toner container comprises: a partitioning member which separates the interior of the toner container into a toner storing portion with the toner present therein and an empty space without toner therein; and a partitioning member moving device which moves the partitioning member in accordance with the amount of toner left in the toner storing portion so that the toner storing portion may have a suitable volume, and a remaining toner quantity detector that detects the position of the partitioning member when the volume of the toner storing portion has been reduced to a predetermined volume or lower; a toner feed device having the toner container mounted thereon and feeding toner discharged from the toner container to a developing unit, wherein the toner supply device supplies toner to the developing unit in accordance with the amount of toner consumed in the developing unit for the process of printing; and a toner container releasing mechanism which, when the amount of toner left in the toner container has been reduced to a predetermined level or lower, causes the toner container to move in the direction opposite to the direction in which the toner container is set into the toner feed device and separate from the toner feed device.