Patent ID: 6408147
Filing Date: 2002-06-18
Classification: B65H

Abstract:
An image forming apparatus, comprising:image forming means for forming an image on a sheet; sheet discharging means for discharging a sheet having an image formed thereon by said image forming means; a sheet stacking tray for stacking thereon sheets discharged from said sheet discharging means; first stack height detecting means for detecting whether a height of a stack of sheets stacked on said sheet stacking tray has reached a first height; second stack height detecting means for detecting whether a height of stack of the sheets stacked on said sheet stacking tray has reached a second height which is higher than the first height; and control means for controlling said image forming apparatus by judging a state of stack of sheets on said sheet stacking tray on the basis of results of detection provided by said first stack height detecting means and said second stack height detecting means, wherein said control means judges said sheet stacking tray to be in a maximum stacked state when said second stack height detecting means has detected that the height of stack of sheets stacked on said sheet stacking tray has reached the second height and, after that, continues judging said sheet stacking tray to be in the maximum stacked state until said first stack height detecting means detects that the height of stack of sheets stacked on said sheet stacking tray has become less than the first height.