Sorting device and image forming apparatus therewith

1. A sorting device provided in a sheet discharge space in an apparatus body, the sorting device shifting a stacking position of discharged sheets in a sheet width direction orthogonal to a sheet discharge direction, thereby to sort the sheets, the sorting device comprising:

a base portion attached to a bottom portion of the sheet discharge space in the apparatus body;

a tray portion supported on the base portion so as to be reciprocatable between a first shift position in which the tray portion is located at one side in the sheet width direction and a second shift position in which the tray portion is located at the other side in the sheet width direction, the tray portion on which the sheets discharged from the apparatus body are stacked at the first shift position and the second shift position,

wherein

the sheets on the tray portion can be retrieved from the one side in the sheet width direction,

the tray portion has:

a tray-side inclined portion arranged upstream of a middle of the tray portion with respect to the sheet discharge direction and extending downstream while inclining upward;

a flat portion arranged downstream of the tray-side inclined portion; and

a cutout portion formed by cutting out, with a predetermined width, a one side end part of the tray portion at the one side in the sheet width direction inward the tray portion, and

the cutout portion has:

a downstream edge portion which is located downstream in the sheet discharge direction, and

an upstream edge portion which is located upstream, in the sheet discharge direction, of a middle of the downstream edge portion with respect to the sheet width direction and which faces the downstream edge portion in the sheet discharge direction,

the upstream edge portion is located on the tray-side inclined portion and a part of the downstream edge portion at the one side is located on the flat portion,

the downstream edge portion extends, from the one side end part of the tray portion, inward across the tray portion while inclining upstream in the sheet discharge direction,

the tray portion has on a top surface thereof a plurality of ribs that extend along the sheet discharge direction and that are arranged at predetermined intervals in the sheet width direction,

of the plurality of ribs, a front rib located at a position overlapping the cutout portion in the sheet width direction is divided, with the cutout portion in between, into an upstream rib, which is located upstream in the sheet discharge direction, and a downstream rib, which is located downstream in the sheet discharge direction,

the upstream and downstream ribs are arranged on a straight line along the sheet discharge direction,

in an upstream end part of the downstream rib in the sheet discharge direction, a rib-side inclined portion is formed that extends upstream in the sheet discharge direction while inclining so as to be increasingly close to the top surface of the tray portion on which the sheets are stacked, and

the rib-side inclined portion is located upstream, in the sheet discharge direction, of the middle, and

an inclination angle a between a tangent line drawn on the downstream edge portion at the middle thereof in the sheet width direction and an imaginary straight line drawn to extend in the sheet width direction through the middle is larger than 10° but smaller than 40°.

2. The sorting device according to claim 1 , wherein

the front rib is, of the plurality of ribs, a rib located farthest to the one side in the sheet width direction.

3. The sorting device according to claim 1 , wherein

the cutout portion further includes a deep side edge portion that extends along the sheet discharge direction and connects the downstream and the upstream edge portion, and

the front rib is divided into the upstream and downstream ribs with the far edge portion in between.

4. The sorting device according to claim 1 , wherein

of the plurality of ribs, the front rib located farthest to the one side in the sheet width direction guides the sheets such that an downstream end part of the sheets in the sheet discharge direction passes over the downstream edge portion.

5. The sorting device according to claim 1 , wherein

the cutout portion has a recessed shape depressed from a top surface of the tray portion toward the bottom portion, and

the cutout portion has a downstream edge portion which is located downstream in the sheet discharge direction, the downstream edge portion has a curve surface that connects together the top surface of the tray portion and an inner surface of the cutout portion.

6. An image forming apparatus, comprising:

an apparatus body including:

an image forming portion which forms images on sheets; and

a sheet discharge space into which the sheets are discharged; and

the sorting device according to claim 1 .