Sheet conveyance apparatus and image forming apparatus

An image forming apparatus comprising:

• a toner image forming unit including an image bearing member and configured to form a toner image on the image bearing member;
• an intermediate transfer member configured to convey the toner image transferred from the image bearing member;
• a transfer member configured to form a secondary transfer portion with the intermediate transfer member and transfer the toner image from the intermediate transfer member onto a sheet;
• a sheet conveyor configured to convey the sheet, the sheet conveyor including a pair of rollers configured to rotate while nipping the sheet at a nip portion;
• a first guide disposed on a same side as the intermediate transfer member with respect to a conveyance path of the sheet and configured to guide the sheet to the secondary transfer portion, the first guide including a distal end having a first portion and a second portion, the second portion of the distal end of the first guide being configured to contact the sheet passing through the conveyance path, and the first portion of the distal end of the first guide and the second portion of the distal end of the first guide both being a part of a downstream-most edge of the first guide in a sheet conveyance direction;
• a second guide disposed on an opposite side of the intermediate transfer member with respect to the conveyance path and configured to face the first guide;
• and
• an optical sensor disposed downstream of a primary transfer portion and upstream of the secondary transfer portion in a conveyance direction of the intermediate transfer member and configured to detect a pattern image formed on the intermediate transfer member by the toner image forming unit, the primary transfer portion being a portion at which the toner image is transferred from the image bearing member to the intermediate transfer member, the optical sensor being further disposed upstream of the nip portion and facing a roller member disposed upstream of the nip portion,
• wherein, when viewed in a sheet width direction perpendicular to the sheet conveyance direction, the first guide is projected to the conveyance path such that a more downstream part thereof in the sheet conveyance direction is closer to the second guide, and
• wherein the first portion of the distal end of the first guide includes a retracted portion disposed corresponding to a first region in the sheet width direction, the retracted portion being retracted with respect to the second portion of the distal end of the first guide such that the second portion of the distal end of the first guide contacts the sheet passing through the conveyance path while the retracted portion, included in the first portion of the distal end of the first guide, does not come into contact with the sheet passing through the conveyance path, the first region including a detection region of the optical sensor in the sheet width direction.