Image forming apparatus provided with a sheet storing unit

An image forming apparatus comprising:

• means for forming an image on a sheet;
• means for generating a signal commanding said image forming means to perform an image forming operation;
• a tray for receiving sheets, which is movable up and down;
• means for transporting sheets ejected from said image forming means to said tray;
• drive means for moving up and down said tray toward and away from a sheet ejection portion of said transporting means;
• means for detecting the volume of sheets stacked on said tray;
• first control means for commanding said drive means to move down said tray in accordance with the volume of sheets stacked on said tray;
• and
• second control means for commanding said drive means to move said tray to a proper position, where the upper surface of said tray or the upper surface of sheets stacked thereon is positioned below the sheet ejection portion of said transporting means with a specified space, when the volume of sheets stacked on said tray is varied during an image forming operation.

An image forming apparatus comprising:

• means for forming an image on a sheet;
• a tray for receiving sheets;
• a transport path for leading sheets ejected from said image forming means to said tray, which includes a first transport section for ejecting the sheets onto said tray and a second transport section arranged upstream of said first transport section;
• means for detecting a sheet traveling in said transport path
• first control means for reducing the speed of a sheet traveling in said first transport section from a first speed to a second speed when the sheet is about to be ejected from said first transport section to said tray;
• and
• second control means for increasing the speed of a sheet traveling in said first transport section from the second speed to a third speed when the next sheet is detected traveling in said second transport section during the operation of said first transport section at the second speed.