An image forming unit comprising: a first process roller configured to form a nip with an object; a second process roller provided to be capable of forming a nip with the first process roller; a bush member including a first journal portion journaling the first process roller and a second journal portion journaling the second process roller with the first process roller rested on the second process roller; a shifting mechanism configured to move the bush member in a direction of abutment and separation in which the first process roller journaled by the first journal portion abuts against and separates from the object; and a drive mechanism configured to actuate the shifting mechanism depending upon an image forming operation, wherein the first journal portion and the second journal portion are juxtaposed in the direction of abutment and separation, the first journal portion includes an escape shaped portion allowing the first process roller to shift in the direction of abutment and separation within the first journal portion and is configured to, when the first process roller is free from nip with the object, journal the first process roller with play in the direction of abutment and separation provided by the escape shaped portion, the first journal portion is configured to, when the first process roller forms a nip with the object by the movement of the bush member actuated by the shifting mechanism, journal the first process roller so that the first process roller is pressed by the object to shift to a position within the first journal portion close to the second process roller, the shifting mechanism includes a support portion supporting the bush member, a biasing member urging the bush member toward the object in the direction of abutment and separation, and a guide portion provided laterally of the bush member contained in the support portion and configured to guide movement of the bush member in the direction of abutment and separation urged by the biasing member, the bush member includes an engagement portion extending toward a bottom portion of the support portion facing the bush member, the engagement portion includes a root portion in a columnar shape and a distal end portion formed at an end of the root portion on the bottom portion side and having a disc shape of a larger diameter than the root portion, the bottom portion of the support portion is provided with a receiving hole receiving the root portion of the engagement portion and allowing the root portion to pass therethrough, a position restricting member movable in a direction perpendicular to the direction of abutment and separation is disposed under the bottom portion, a locking hole through which the root portion having passed through the receiving hole passes is formed in the position restricting member, the locking hole is a single continuous hole in which a first locking hole having a width substantially equal to a diameter of the root portion of the engagement portion and a second locking hole having a width substantially equal to a diameter of the distal end portion of the engagement portion are integrally formed, the engagement portion projects beyond the bottom portion of the support portion to have different amounts of projection between when the position restricting member moves to a position where the first locking hole locks with the distal end portion and when the position restricting member moves to a position where the second locking hole coincides with both the root portion and the distal end portion, the first process roller becomes free from nip with the object when the position restricting member moves to the position where the first locking hole (291 a) locks with the distal end portion, the first process roller forms the nip with the object when the position restricting member moves to the position where the second locking hole coincides with both the root portion and the distal end portion, and the drive mechanism is configured to move the position restricting member between the locking position and the unlocking position. a first process roller configured to form a nip with an object; a second process roller provided to be capable of forming a nip with the first process roller; a bush member including a first journal portion journaling the first process roller and a second journal portion journaling the second process roller with the first process roller rested on the second process roller; a shifting mechanism configured to move the bush member in a direction of abutment and separation in which the first process roller journaled by the first journal portion abuts against and separates from the object; and a drive mechanism configured to actuate the shifting mechanism depending upon an image forming operation,