DEVELOPER STORAGE UNIT, DEVELOPING DEVICE, AND PROCESS CARTRIDGE

摘要

PROBLEM TO BE SOLVED: To provide a developer storage unit capable of notifying a user of the amount of developer without the need to receive power from an image forming apparatus body.SOLUTION: A developer storage unit includes: a container that stores developer; a movable member that can be moved outside the container; a piezoelectric element that is provided inside the container; and notification means for notifying a user of information concerning the amount of a developer in the container by using an output voltage of the piezoelectric element. The piezoelectric element is brought close to or separated from the developer in conjunction with the movement of the movable member.