Sheet detecting apparatus and image forming apparatus

A sheet detecting apparatus comprising:

• a sheet supporting surface configured to support a sheet;
• a first sensor flag comprising a first flag portion configured to pivot around a first pivot shaft extending in an axial direction, a first contact portion configured to pivot integrally with the first flag portion and configured to contact, at a first position in the axial direction, with the sheet supported by the supporting surface, and a third contact portion configured to pivot integrally with the first flag portion and configured to contact, at a third position, with the sheet supported by the supporting surface, the third position being located on a side opposite from the first position across a second position in the axial direction;
• a second sensor flag comprising a second flag portion configured to pivot around a second pivot shaft, and a second contact portion configured to pivot integrally with the second flag portion and configured to contact, at the second position, with the sheet supported by the supporting surface;
• a first detection sensor configured to transit to a first state of outputting a first detection signal and to a second state of outputting a second detection signal different from the first detection signal, the first detection sensor transiting to either one of the first state and the second state in response to a position of the first flag portion;
• and
• a second detection sensor configured to transit to a third state of outputting a third detection signal and to a fourth state of outputting a fourth detection signal different from the third detection signal, the second detection sensor transiting to either one of the third state and the fourth state in response to a position of the second flag portion,
• wherein in a case where no sheet is disposed at the first, second and third positions, the first detection sensor is brought to the first state and the second detection sensor is brought to the third state,
• wherein in a case where a sheet is disposed at the first position and no sheet is disposed at the second and third positions, the first detection sensor is brought to the second state and the second detection sensor is brought to the third state,
• wherein in a case where a sheet is disposed at the first and second positions and no sheet is disposed at the third position, the first detection sensor is brought to the second state and the second detection sensor is brought to the fourth state, and
• wherein a sheet is disposed at the first, second and third positions, the first detection sensor is brought to the first state and the second detection sensor is brought to the fourth state.