Patent ID: 8023837
Filing Date: 2011-09-20
Classification: G03G

Abstract:
1. An image forming apparatus comprising: an image forming portion for forming an image on a sheet; a sheet stack portion for stacking a sheet; a discharge portion for discharging the sheet on which an image is formed by said image forming portion, to said sheet stack portion; a sheet detection portion for detecting the sheet on which an image is formed before the sheet on which the image is formed by said image forming portion is discharged to said sheet stack portion; a fully stacked condition detection portion for detecting whether sheets stacked in the sheet stack portion are in a fully stacked condition; and a determining portion that, at a time when a predetermined time period (t wherein the determination portion, at the time when the predetermined time period elapses after the sheet detection portion detects the leading edge of the sheet, in a case where the fully stacked condition detection portion detects the leading edge of the sheet detected by the sheet detection portion and finishes detecting the sheet for a period shorter than the predetermined conveying time period, determines a condition as a first abnormal condition, and wherein the determination portion, after a period longer than the predetermined time period elapses after the sheet detection portion detects the leading edge of the sheet, in a case where the fully stacked condition detection portion does not detect the sheet detected by the sheet detection portion yet, determines a condition as a second abnormal condition.