Image forming apparatus

An image forming apparatus comprising:

• a storage portion configured to house toner and a first magnetic material;
• a magnetic material unit including a permanent magnet and a second magnetic material, the permanent magnet including a first end surface and a second end surface, the second magnetic material being lower in residual magnetic flux density than the permanent magnet, the magnetic material unit being configured to move inside the storage portion based on an amount of toner in the storage portion;
• and
• a sensor configured to output a signal based on a magnetic field formed by the permanent magnet,
• wherein, in a case where a direction from one of magnetic poles to another magnetic pole of the permanent magnet is defined as a first direction, the first end surface is one end of the permanent magnet in the first direction, and the second end surface is another end of the permanent magnet on a side opposite to the one end in the first direction,
• wherein, in a case where a position of the permanent magnet closest to the sensor is defined as a proximity position, and the permanent magnet is at the proximity position, a shortest distance between the first end surface and the sensor is longer than a shortest distance between the second end surface and the sensor,
• wherein, in a case where the permanent magnet is at the proximity position, a shortest distance between the first magnetic material and the second magnetic material is smaller than a shortest distance between the first magnetic material and the first end surface, and
• wherein, as viewed in the first direction, the second magnetic material includes an overlap portion configured to overlap with the first end surface, and a non-overlap portion configured not to overlap with the first end surface.