Image formation apparatus

An image formation apparatus comprising:

• a toner cartridge storing toner;
• a developer;
• a hopper temporarily storing toner supplied from the toner cartridge and supplying the developer with the toner;
• a magnetic sensor including a magnet and a reed switch that determines whether the magnet is within a detection area thereof, one of which is fixed to a predetermined position, and the other of which is configured to move downwards as a surface level of toner stored in a toner storage of the hopper decreases and thus serves as a surface level detector for detecting the surface level;
• a lifter configured to periodically lift the surface level detector above the surface level such that the magnet goes out of the detection area;
• an ON-edge detector configured to detect ON-edges each indicating a point in time when the magnet has entered the detection area;
• a misdetection determiner configured to determine an ON-edge as false when the lifter has not lifted the surface level detector after a point in time indicated by the previous ON-edge;
• and
• a toner supplier configured to supply the hopper with the toner from the toner cartridge under a condition that an ON-edge is not determined as false by the misdetection determiner.