Patent attributes
An abnormal sheet delivery detection device includes a convey device, first pile device, noncontact-type detection unit, and first releasing unit. The convey device includes a sheet holding unit for holding a sheet, and conveys the sheet held by the sheet holding unit. The sheet released from the sheet holding unit is piled on the first pile device at a predetermined sheet release position. The noncontact-type detection unit arranged downstream of the sheet release position in a sheet convey direction detects a presence/absence of the sheet. The first releasing unit selectively switches between a first state wherein the sheet held by the sheet holding unit is released and piled on the first pile device, and a second state wherein the sheet held by the sheet holding unit is conveyed downstream in the sheet convey direction by the first convey device without releasing the sheet.
