Sheet conveyance device and image forming apparatus provided therewith

A sheet conveyance device comprising:

• a sheet conveyance passage provided in an apparatus main body to convey a sheet;
• a first sheet stacking portion arranged inside the apparatus main body, the first sheet stacking portion including:
• a bottom face part on which the sheet is stacked;
• and
• a lifting plate provided so as to be movable up and down with respect to the bottom face part, the lifting plate moving the sheet on the bottom face part up and down to arrange the sheet at a feeding position,
• a first feeding portion that feeds the sheet stacked on the first sheet stacking portion to the sheet conveyance passage;
• a second feeding portion that feeds the sheet fed from a loading port provided in a side part of the apparatus main body to the first feeding portion;
• a bypass conveyance passage that extends from the second feeding portion to the first feeding portion, the bypass conveyance passage conveying the sheet fed from the second feeding portion to the first feeding portion;
• a sheet detection mechanism provided in the first feeding portion, the sheet detection mechanism being able to detect whether the sheet is stacked on the first sheet stacking portion;
• a driving portion that can switch a rotation direction thereof, the driving portion, when rotating in a forward direction, driving the first feeding portion and, when rotating in a reverse direction, driving the second feeding portion;
• and
• a control portion that controls conveyance of the sheet,
• wherein
• the sheet detection mechanism has:
• an actuator that can swing along a sheet conveyance direction while in contact with the sheet stacked on the first sheet stacking portion and arranged at the feeding position by the lifting plate or the sheet conveyed by the second feeding portion through the bypass conveyance passage to the first feeding portion;
• and
• a detection sensor that detects the actuator at a predetermined detection position, and
• the control portion controls such that,
• when the sheet is fed from the first sheet stacking portion, the lifting plate moves the sheet stacked on the first sheet stacking portion to the feeding position and, when the sheet is detected by the sheet detection mechanism, the driving portion rotates in the forward direction so that the first feeding portion feeds the sheet, and
• when the sheet is conveyed from the second feeding portion, the driving portion rotates in the reverse direction so that the sheet is conveyed to the first feeding portion by the second feeding portion and, when the detection sensor detects at the detection position the actuator swinging by making contact with the sheet conveyed from the second feeding portion, the driving portion is switched to rotate in the forward direction so that the first feeding portion feeds the sheet.