Sheet conveying device capable of acquiring pay-out amount of sheet from stack of sheets without providing dedicated sensor, an image forming apparatus, and acquisition method

Abstract

A sheet conveying device includes a sheet supply portion, a detection portion, and an acquisition processing portion. The sheet supply portion supplies an uppermost sheet in a stack of sheets lifted by a lift portion. The detection portion detects the sheet supplied by the sheet supply portion. The acquisition processing portion acquires a pay-out amount of the sheet from the stack of sheets based on an elapsed time from a start of supply of the sheet by the sheet supply portion to a time when the sheet is detected by the detection portion, that is measured at a timing at which the stack of sheets is lifted by the lift portion, and an elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion, that is measured after the timing.

1 . A sheet conveying device, comprising:
 a lift portion which lifts a stack of sheets;   a sheet supply portion which includes a conveying member which rotates while being in contact with an upper surface of the stack of sheets lifted by the lift portion, and supplies a sheet that comes into contact with the conveying member to a conveying path;   a detection portion which detects the sheet supplied by the sheet supply portion on the conveying path;   a first measurement processing portion which measures, when the stack of sheets is lifted by the lift portion, an elapsed time from a start of supply of the sheet by the sheet supply portion to a time when the sheet is detected by the detection portion;   a second measurement processing portion which measures, after the measurement by the first measurement processing portion, an elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion; and   an acquisition processing portion which acquires, based on a measurement result obtained by the first measurement processing portion and a measurement result obtained by the second measurement processing portion, a pay-out amount of an acquisition target sheet from the stack of sheets at a time of a start of supply of the acquisition target sheet, the acquisition target sheet having been supplied at a time of the measurement by the second measurement processing portion.   
     
     
         2 . The sheet conveying device according to  claim 1 , comprising:
 a sheet storing portion which is detachably provided in a housing of the sheet conveying device and stores the stack of sheets, wherein   the lift portion is provided in the sheet storing portion, and   when the lift of the stack of sheets by the lift portion is a first lift after the sheet storing portion is attached to the housing, the first measurement processing portion measures the elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion.   
     
     
         3 . The sheet conveying device according to  claim 1 , wherein
 the first measurement processing portion measures the elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion every time the stack of sheets is lifted by the lift portion, and   the acquisition processing portion acquires, based on a last measurement result obtained by the first measurement processing portion, the pay-out amount of the acquisition target sheet from the stack of sheets at the time of the start of supply of the acquisition target sheet.   
     
     
         4 . The sheet conveying device according to  claim 1 , wherein
 the first measurement processing portion measures, at a time when the sheet is first supplied after the stack of sheets is lifted by the lift portion, the elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion.   
     
     
         5 . The sheet conveying device according to  claim 1 , wherein
 the sheet supply portion includes   a separation portion which separates, from the sheet conveyed by the conveying member, an accompanying sheet accompanying the sheet, and   the sheet conveying device comprises:   a determination processing portion which determines, based on an acquisition result obtained by the acquisition processing portion, whether or not the acquisition target sheet has protruded beyond the separation portion; and   a notification processing portion which, when it is determined that the acquisition target sheet has protruded beyond the separation portion, notifies to that effect.   
     
     
         6 . An image forming apparatus, comprising:
 the sheet conveying device according to  claim 1 ; and   an image forming portion which forms an image on the sheet conveyed by the sheet conveying device.   
     
     
         7 . An acquisition method executed in a sheet conveying device including a lift portion which lifts a stack of sheets, a sheet supply portion which includes a conveying member which rotates while being in contact with an upper surface of the stack of sheets lifted by the lift portion, and supplies a sheet that comes into contact with the conveying member to a conveying path, and a detection portion which detects the sheet supplied by the sheet supply portion on the conveying path, the acquisition method comprising:
 a first measurement step of measuring, when the stack of sheets is lifted by the lift portion, an elapsed time from a start of supply of the sheet by the sheet supply portion to a time when the sheet is detected by the detection portion;   a second measurement step of measuring, after the measurement in the first measurement step, an elapsed time from the start of supply of the sheet by the sheet supply portion to the time when the sheet is detected by the detection portion; and   an acquisition step of acquiring, based on a measurement result obtained in the first measurement step and a measurement result obtained in the second measurement step, a pay-out amount of an acquisition target sheet from the stack of sheets at a time of a start of supply of the acquisition target sheet, the acquisition target sheet having been supplied at a time of the measurement in the second measurement step.