Image forming apparatus

An image forming apparatus comprising:

• a first transmission member;
• a second transmission member;
• a third transmission member configured to rotate about a rotation axis in a first rotation direction, the third transmission member configured to engage with the first transmission member and being apart from the second transmission member;
• a fourth transmission member configured to rotate about the rotation axis in the first rotation direction, the fourth transmission member configured to engage with the second transmission member and being apart from the first transmission member;
• a biasing member connected to the third transmission member and the fourth transmission member, and the biasing member configured to bias one of the third transmission member and the fourth transmission member in the first rotation direction and to bias an other of the third transmission member and the fourth transmission member in a second rotation direction opposite to the first rotation direction;
• and
• a connection portion that is connected to the first transmission member and the second transmission member to form a drive train forming a closed loop, the closed loop including the first transmission member, the second transmission member, the third transmission member, the biasing member, and the fourth transmission member, wherein
• a rotational speed of the third transmission member is the same as a rotational speed of the fourth transmission member.