An image forming system includes an image forming apparatus and a feeding device, the image forming apparatus including an image forming unit, a housing, an opening/closing door openable and closable between a first closed position and a first open position, and a support unit openable and closable between a second closed position and a second open position and configured to support a sheet when the support unit is at the second open position, the feeding device being movable in a direction horizontal to the image forming apparatus, configured to move to a coupled position and a decoupled position and feed the sheet to the image forming apparatus when the feeding device is at the coupled position, wherein when the feeding device is at the decoupled position and the opening/closing door is at the first open position, the feeding device overlaps the support unit as viewed from a first direction.

A housing structure includes a main housing, a first cover that opens and closes by rotating with respect to the main housing about a first axis along a horizontal direction, a second cover provided further inside than the first cover and that opens and closes with respect to the main housing together with the first cover by rotating around a second axis parallel to the first axis, a regulation section that regulates the second cover in a closed state in which the second cover is closed, and a restriction section that, when the first cover is closed, restricts the release of regulation by the regulation section.

A housing structure includes a main housing, a first cover configured to open and close by rotating with respect to the main housing about a first axis along a horizontal direction, a second cover provided further inside than the first cover and configured to open and close with respect to the main housing together with the first cover by rotating around a second axis parallel to the first axis, a regulation section configured to regulate the second cover in a closed state in which the second cover is closed, and a restriction section configured to, when the first cover is closed, restrict the release of regulation by the regulation section.

An image forming apparatus includes: an apparatus body; an opening and closing member; a connection member having a first engagement portion that is engaged with the apparatus body and a second engagement portion that is engaged with the opening and closing member; a pressing member having a third engagement portion that is engaged with the connection member, a pressing portion that is capable of pressing the pressed portion of the opening and closing member, and an urged portion; an urging member urging the urged portion such that the pressing portion is pressed against the pressed portion. The second engagement portion is movable between a first position and a second position. When the opening and closing member is between a closed position and an open position, the pressing portion moves relative to the pressed portion while pressing the pressed portion, in conjunction with rotation of the opening and closing member.

A sheet thickness detector includes a conveyance roller pair, a pressing member, a separation mechanism, and a displacement detector. The conveyance roller pair includes a conveyance roller rotatable about a drive shaft to convey a sheet in a sheet conveyance direction, and a detection roller separately contactable with the conveyance roller to nip the sheet at an initial position. The pressing member presses the detection roller to the conveyance roller in a contact direction. The separation mechanism separates the detection roller from the conveyance roller in a separation direction. The displacement detector detects a displacement of the detection roller in the separation direction from the initial position to detect a thickness of the sheet in response to a nip of the sheet by the conveyance roller pair. The separation mechanism is decoupled from the detection roller in response to a detection of the thickness of the sheet.

A spring mounting structure includes a first structural member and a second structural member. The first structural member includes: a first abutting surface to abut on one end of a compression spring; and a temporary holding portion to temporarily hold the compression spring in an uncompressed state. The second structural member includes: a second abutting surface to abut on another end of the compression spring; and a tapered surface to, when the second structural member is assembled in a predetermined assembling direction intersecting a compression direction of the compression spring, guide the other end of the compression spring in the uncompressed state temporarily held by the temporary holding portion to the second abutting surface such that the compression spring is mounted in a compressed state between the first and second abutting surfaces.

A spring mounting structure includes a first structural member and a second structural member. The first structural member includes: a first abutting surface to abut on one end of a compression spring; and a temporary holding portion to temporarily hold the compression spring in an uncompressed state. The second structural member includes: a second abutting surface to abut on another end of the compression spring; and a tapered surface to, when the second structural member is assembled in a predetermined assembling direction intersecting a compression direction of the compression spring, guide the other end of the compression spring in the uncompressed state temporarily held by the temporary holding portion to the second abutting surface such that the compression spring is mounted in a compressed state between the first and second abutting surfaces.