Belt conveyance device and image forming apparatus

An image forming apparatus comprising:

• a plurality of image bearing members configured to respectively bear toner images of different colors;
• a belt of an endless shape configured to rotationally move, wherein the toner images borne on the plurality of image bearing members are transferred to the belt;
• a first stretching roller and a second stretching roller configured to suspend the belt in a tensioned manner;
• a first bearing member configured to support a shaft end portion on a first end side of the first stretching roller with respect to a width direction perpendicular to a movement direction of the belt;
• a second bearing member configured to support a shaft end portion on a second end side of the first stretching roller with respect to the width direction;
• a first frame portion including a holding portion configured to hold the first bearing member;
• a second frame portion including a holding portion configured to hold the second bearing member, the belt being arranged between the first frame portion and the second frame portion with respect to the width direction,
• wherein the first bearing member includes a first restriction portion which is restricted from rotating relative to the first frame portion and the second bearing member includes a second restriction portion which is restricted from rotating relative to the second frame portion, and
• wherein, as viewed from a direction perpendicular to the width direction, a phase of shape of the first restriction portion in a state of being held by the first frame portion and a phase of shape of the second restriction portion in a state of being held by the second frame portion are equal to each other.

An attachment method for attaching a roller which suspends a belt of an endless shape configured to rotationally move to a belt conveyance device including the belt in which the belt is arranged between a first frame portion and a second frame portion with respect to a width direction perpendicular to a movement direction of the belt, the attachment method comprising:

• attaching a first bearing member to a first end side of the roller with respect to the width direction;
• inserting a second end side opposite to the first end side with respect to the width direction of the roller with the first bearing member attached thereto into a second holding portion of the second frame portion, and then mounting the first end side of the roller with the first bearing member attached thereto to a first holding portion of the first frame portion from a first direction concerning the width direction;
• and
• mounting a second bearing member to the second holding portion of the second frame portion and the second end side of the roller from the first direction.