Patent ID: 9128448
Filing Date: 2015-09-08
Classification: G03G

Abstract:
1. An image forming apparatus comprising: a fixing unit including a first rotating member heated by a heating source, a second rotating member facing the first rotating member, and a fixing nip forming mechanism forming a fixing nip between the first rotating member and second rotating member by bringing the second rotating member into pressure contact with the first rotating member; an apparatus main body to which the fixing unit is detachably installed; a nip pressure changing member configured to press the fixing nip forming mechanism and to change a pressure of the fixing nip by rotating around a rotation axis; a driving source that rotates the nip pressure changing member; and a clutch mechanism configured to permit a transmission of a rotation from the driving source to the nip pressure changing member and to restrict a transmission of a rotation from the nip pressure changing member to the driving source, wherein the clutch mechanism includes; a driving piece configured to rotate along with a rotation of the driving source; a driven piece being slidable along the rotation axis direction between an engage position where the driven piece engages with the driving piece and an engage releasing position where the engagement of the driven piece with the driving piece is released, and rotating in a body with the nip pressure changing member; and a biasing member configured to bias the driven piece to the engage position, wherein when the driving piece rotates with respect to the driven piece, the driven piece rotates in a body with the driving piece as the driven piece is kept at the engage position by a bias force of the biasing member, when the driven piece rotates with respect to the driving piece, the driving piece keeps a rotation stopped state as the driven piece slides from the engage position to the engage releasing position against the bias force of the biasing member.