Drive transmission device, feeding device, and printing apparatus

A drive transmission device comprising:

• a cam portion configured to rotate about a rotation shaft;
• a drive source configured to drive the rotation shaft to rotate the cam portion;
• a drive gear train configured to transmit a driving force from the drive source to the rotation shaft;
• a planetary gear configured to engage with part of the drive gear train;
• a holder configured to hold the planetary gear such that the planetary gear is configured to swing between a first position at which the planetary gear engages with the part of the drive gear train and a second position at which the planetary gear does not engage with the part of the drive gear train;
• a cam follower configured to be in contact with the cam portion and move, by rotation of the cam portion, in a first direction to be close to the rotation shaft and in a second direction to be away from the rotation shaft;
• and
• an extension spring configured to press the cam follower against the cam portion, wherein
• the cam portion includes
• a first cam defining a maximum distance between the cam follower and the rotation shaft and
• a second cam having an inner edge portion positioned closer to the rotation shaft than an outer edge portion of the first cam,
• in a process of the cam follower moving in the second direction by the rotation of the cam portion, a portion of the cam portion, the portion being in contact with the cam follower, is switched from the second cam to the first cam, and
• torque acting on the rotation shaft when the inner edge portion is in contact with the cam follower acts in a direction to move the planetary gear from the first position to the second position.