A cassette portion includes a side guide, an end guide, and a paper detection portion. The side guide is movable in X direction and controls a motion of a first end portion of paper. The end guide is provided to the side guide to be movable in Y direction, and restricts a motion of a second end portion of the paper. The paper detection portion detects the first restricting position in the X direction of the side guide and a second restricting position in the Y direction of the end guide in a restricted state of the paper. The end guide includes a detection target portion formed such that detection information to be detected by the paper detection portion varies in the Y direction. The paper detection portion detects the first restricting position and the second restricting position by obtaining detection information from the detection target portion.

A cassette portion includes a side guide, an end guide, and a paper detection portion. The side guide is movable in X direction and controls a motion of a first end portion of paper. The end guide is provided to the side guide to be movable in Y direction, and restricts a motion of a second end portion of the paper. The paper detection portion detects the first restricting position in the X direction of the side guide and a second restricting position in the Y direction of the end guide in a restricted state of the paper. The end guide includes a detection target portion formed such that detection information to be detected by the paper detection portion varies in the Y direction. The paper detection portion detects the first restricting position and the second restricting position by obtaining detection information from the detection target portion.

A container member includes a container body that contains a recording medium and that tilts such that a leading edge of the contained recording medium is higher than a trailing edge, and a leading edge restriction portion that comes into contact with a portion of the leading edge except for at least a first end portion and that restricts a position of the leading edge.

An image forming apparatus includes a sensor, a tray, a gear, a protruding portion, and a processor. The sensor has a light transmitting unit and light receiving units and is configured to generate an output signal in accordance with an amount of light received by the light receiving units. The gear is configured to rotate in accordance with an amount of sheets stacked on the tray. The protruding portion is configured to rotate with the gear and move into a light path of light emitted from the light emitting unit to the light receiving units to partially block the light, the protruding portion having a width that determines how much light in the light path is blocked and varies gradually from a first end thereof to a second end thereof. The processor is configured to determine the amount of sheets stacked on the tray based on the output signal.

There is provided a sheet storage device including a regulation unit that includes a first contact portion configured to contact a stacking unit, and a second contact portion configured to contact a facing member. The first contact portion contacts the stacking unit in a state of being urged toward the stacking unit. The second contact portion contacts the facing member in a state of being urged toward the facing member.

There is provided a sheet storage device including a regulation unit that includes a first contact portion configured to contact a stacking unit, and a second contact portion configured to contact a facing member. The first contact portion contacts the stacking unit in a state of being urged toward the stacking unit. The second contact portion contacts the facing member in a state of being urged toward the facing member.

A sheet conveyance apparatus includes a sheet supporting tray to support a sheet, a sheet conveyance unit to convey the sheet supported on the sheet supporting tray, a first detection sensor to detect the supported sheet at a first detection position, and a second detection sensor to detect the supported sheet at a second detection position farther from a center of the sheet supporting tray in a sheet width direction than the first detection position. In addition, a control unit controls the sheet conveyance unit in a first mode in a case where the first and second detection sensors detect the sheet, and controls the sheet conveyance unit in a second mode in which a sheet conveyance speed is slower than that of the first mode in a case where the first detection sensor detects the sheet and the second detection sensor detects no sheet.

A sheet supporting apparatus includes a positioning device to position a regulating portion to a sheet support. The positioning device includes a first group of teeth provided on the sheet support, a second group of teeth disposed at a position different from the first group of teeth provided on the sheet support, a third group of teeth provided on a regulator and capable of transiting to a first state of engaging with the first group of teeth and to a second state of engaging with less area of the first group of teeth than that in the first state, and a fourth group of teeth provided on the regulator and capable of transiting to a third state of engaging with the second group of teeth and to a fourth state of engaging with less area of the second group of teeth than that in the third state.

A sheet supporting apparatus includes a positioning device to position a regulating portion to a sheet support. The positioning device includes a first group of teeth provided on the sheet support, a second group of teeth disposed at a position different from the first group of teeth provided on the sheet support, a third group of teeth provided on a regulator and capable of transiting to a first state of engaging with the first group of teeth and to a second state of engaging with less area of the first group of teeth than that in the first state, and a fourth group of teeth provided on the regulator and capable of transiting to a third state of engaging with the second group of teeth and to a fourth state of engaging with less area of the second group of teeth than that in the third state.

A sheet feeder apparatus includes a width detector for a sheet placed on a sheet placement portion, a conveyor for conveying sheets while separating the sheets one by one, a first detector for detecting a sheet having a first width at a plurality of first positions, a second detector for detecting a sheet having a second width that is not detected by the first sheet detector at a plurality of second positions, and a controller for determining skewing of a sheet based on a result of the detection of the sheet performed by the first detector if the width of the sheet is the first width, and determining skewing of a sheet based on a result of the detection performed by the second detector if the width of the sheet is the second width.