Image forming apparatus having a developer detecting unit

An image forming apparatus comprising:

• a developer container unit including
• an agitating member configured to rotate and agitate developer,
• a first electrode,
• a second electrode disposed to face the first electrode with a gap therebetween such that the gap has a smallest portion located below a rotation center of the agitating member and a remote portion wider than the smallest portion and located above the smallest portion, and
• a frame body configured to contain the agitating member and the developer and have a first wall surface having the first electrode disposed thereon and a second wall surface having the second electrode disposed thereon;
• and
• a developer detecting unit configured to detect an amount of the developer by using an output value output in accordance with a capacitance formed between the first electrode and the second electrode, the developer detecting unit capable of detecting a first amount of developer and a second amount of developer that is smaller than the first amount of developer,
• wherein when the output value corresponding to the first amount of developer is defined as a first reference value and a value having a first difference from the first reference value is defined as a second reference value indicating a magnitude of the output value corresponding to the second amount of developer, the first difference varies in accordance with a magnitude of the first reference value.