Paper sheet stacking apparatus, image forming apparatus, paper sheet processing apparatus, image forming system and method for controlling paper sheet stacking operation

An image forming apparatus, comprising:

• an image forming section to form an image on a paper sheet;
• an ejecting section to eject the paper sheet on which the image is formed;
• a stacking tray to stack the paper sheet, ejected by the ejecting section, thereon;
• an up-and-down driving section to drive the stacking tray up and down in a vertical direction corresponding to a height direction of paper sheets when stacked on the stacking tray;
• a paper-sheet upper surface detecting section to detect an upper-most surface of the paper sheets stacked onto the stacking tray;
• a position detecting section to detect a position of the stacking tray by using a plurality of sensors respectively disposed at different positions along the vertical direction in which the stacking tray moves up and down;
• and
• a control section that controls the up-and-down driving section to drive the stacking tray so as to keep a position of the upper-most surface of the paper sheets, which is detected by the paper-sheet upper surface detecting section, constant, and determines whether or not the stacking tray is currently in a full loaded condition, based on the position of the stacking tray detected by the position detecting section;
• wherein the control section confirms information regarding a weight of the paper sheets, calculates a thickness of each of the paper sheets based on a number of the paper sheets stacked onto the stacking tray and a position of any one of the plurality of sensors provided in the position detecting section, selects any one of the plurality of sensors as a full-loaded condition position sensor that indicates the full loaded condition of the stacking tray based on the information regarding the weight of the paper sheets and the calculated thickness of each of the paper sheets, and determines whether or not the stacking tray is currently in the full loaded condition, based on the position of the stacking tray, which is detected by the full-loaded condition position sensor.

A paper sheet processing apparatus, comprising:

• a paper sheet processing section to apply a paper sheet processing to a paper sheet;
• an ejecting section to eject the paper sheet to which the paper sheet processing is applied;
• a stacking tray to stack the paper sheet, ejected by the ejecting section, thereon;
• an up-and-down driving section to drive the stacking tray up and down in a vertical direction corresponding to a height direction of paper sheets when stacked on the stacking tray;
• a paper-sheet upper surface detecting section to detect an upper-most surface of the paper sheets stacked onto the stacking tray;
• a position detecting section to detect a position of the stacking tray by using a plurality of sensors respectively disposed at different positions along the vertical direction in which the stacking tray moves up and down;
• and
• a control section that controls the up-and-down driving section to drive the stacking tray so as to keep a position of the upper-most surface of the paper sheets, which is detected by the paper-sheet upper surface detecting section, constant, and determines whether or not the stacking tray is currently in a full loaded condition, based on the position of the stacking tray detected by the position detecting section;
• wherein the control section confirms information regarding a weight of the paper sheets, calculates a thickness of each of the paper sheets based on a number of the paper sheets stacked onto the stacking tray and a position of any one of the plurality of sensors provided in the position detecting section, selects any one of the plurality of sensors as a full-loaded condition position sensor that indicates the full loaded condition of the stacking tray based on the information regarding the weight of the paper sheets and the calculated thickness of each of the paper sheets, and determines whether or not the stacking tray is currently in the full loaded condition, based on the position of the stacking tray, which is detected by the full-loaded condition position sensor.

An image forming system, comprising:

• an image forming section to form an image on a paper sheet;
• a paper sheet processing section to apply a paper sheet processing to the paper sheet on which the image is formed;
• an ejecting section to eject the paper sheet to which the paper sheet processing is applied;
• a stacking tray to stack the paper sheet, ejected by the ejecting section, thereon;
• an up-and-down driving section to drive the stacking tray up and down in a vertical direction corresponding to a height direction of paper sheets when stacked on the stacking tray;
• a paper-sheet upper surface detecting section to detect an upper-most surface of the paper sheets stacked onto the stacking tray;
• a position detecting section to detect a position of the stacking tray by using a plurality of sensors respectively disposed at different positions along the vertical direction in which the stacking tray moves up and down;
• and
• a control section that controls the up-and-down driving section to drive the stacking tray so as to keep a position of the upper-most surface of the paper sheets, which is detected by the paper-sheet upper surface detecting section, constant, and determines whether or not the stacking tray is currently in a full loaded condition, based on the position of the stacking tray detected by the position detecting section;
• wherein the control section confirms information regarding a weight of the paper sheets, calculates a thickness of each of the paper sheets based on a number of the paper sheets stacked onto the stacking tray and a position of any one of the plurality of sensors provided in the position detecting section, selects any one of the plurality of sensors as a full-loaded condition position sensor that indicates the full loaded condition of the stacking tray based on the information regarding the weight of the paper sheets and the calculated thickness of each of the paper sheets, and determines whether or not the stacking tray is currently in the full loaded condition, based on the position of the stacking tray, which is detected by the full-loaded condition position sensor.

A method for controlling a paper sheet stacking operation which is implemented in a paper sheet stacking apparatus that stacks paper sheets having been ejected thereto, the apparatus comprising a stacking tray to stack the paper sheets;

• an up-and-down driving section to drive the stacking tray up and down in a vertical direction corresponding to a height direction of the paper sheets when stacked;
• a paper-sheet upper surface detecting section to detect an upper-most surface of the paper sheets stacked onto the stacking tray;
• a position detecting section to detect a position of the stacking tray by using a plurality of sensors respectively disposed at different positions along the vertical direction in which the stacking tray moves up and down;
• and a control section that controls the up-and-down driving section to drive the stacking tray so as to keep a position of the upper-most surface of the paper sheets, which is detected by the paper-sheet upper surface detecting section, constant, and determines whether or not the stacking tray is currently in a full loaded condition, based on the position of the stacking tray, detected by the position detecting section, and the method comprising:
• confirming information regarding a weight of the paper sheets;
• calculating a thickness of each of the paper sheets based on a number of the paper sheets stacked onto the stacking tray and a position of any one of the plurality of sensors provided in the position detecting section;
• selecting any one of the plurality of sensors as a full-loaded condition position sensor that indicates the full loaded condition of the stacking tray based on the information regarding the weight of the paper sheets and the calculated thickness of each of the paper sheets;
• and
• determining whether or not the stacking tray is currently in the full loaded condition, based on the position of the stacking tray which is detected by the full-loaded condition position sensor.