Patent ID: 8849178

Claim:
A sheet detecting apparatus which detects a sheet conveyed by a conveying portion which conveys the sheet, the sheet detecting apparatus comprising: a sheet detecting member including a plurality of abutment surfaces against which a leading edge of the sheet conveyed by the conveying portion abuts, the plurality of abutment surfaces being formed in a peripheral direction of the sheet detecting member, the plurality of abutment surfaces of the sheet detecting member being pressed by the conveyed sheet to rotate from a waiting position; a sensor which generates a signal based on a position of the plurality of abutment surfaces; a shaft connected to the sheet detecting member to support the sheet detecting member in a rotatable manner; a first rotary member connected to the shaft and configured to rotate around a first rotation center; a second rotary member connected to the first rotary member and configured to rotate around a second rotation center, wherein if N is a number of the plurality of abutment surfaces, one revolution of the second rotary member around the second rotation center makes 1/N revolution of the first rotary member around the first rotation center; and a biasing portion configured to bias the second rotary member to be positioned at a predetermined position in a rotation direction of the second rotary member around the second rotation center so as to position one of the plurality of abutment surfaces at the waiting position.