Manual paper feed device, image forming apparatus, and image forming method

Abstract

A manual paper feed device includes: a manual feed tray on which sheets are stacked; a paper feeding roller that feeds the sheets on the manual feed tray into an image forming unit; a pressing tray that is, with the sheets stacked thereon, rotatably supported and a downstream side of which in a conveying direction of the sheets is biased to the paper feeding roller side; a bias releasing member that separates and holds the pressing tray in a direction opposed to the bias direction and releases the biasing; and a sensor that detects at least one of presence or absence of the sheets on the manual feed tray and a bias releasing state of the pressing tray. The manual paper feed device prohibits paper feeding operation when the bias releasing state of the pressing tray is detected regardless of presence or absence of sheets stacked on the pressing tray.

1 . A manual paper feed device comprising:
 a manual feed tray configured to stack a sheet;   a paper feeding roller configured to feed the sheets on the manual feed tray into an image forming unit;   a pressing tray configured to stack the sheet, rotatably supported with a first pivoting shaft as a first fulcrum and a downstream side of which in a conveying direction of the sheet is biased to the paper feeding roller side;   a bias releasing member configured to separate and hold the pressing tray in a direction opposed to the bias direction and release the biasing;   a sensor configured to detect at least one of presence or absence of the sheet on the manual feed tray and a bias releasing state of the pressing tray;   a switching member configured to switch a biasing state and the bias releasing state of the pressing tray, coupled to the bias releasing member;   a first detected member rotatably supported with a second pivoting shaft as a second fulcrum in contact with the sheet on the pressing tray, and provided in a position detectable by the sensor when the sheet is not present on the pressing tray; and   a second detected member provided in a position detectable by the sensor when the pressing tray is in the bias releasing state.   
     
     
         2 . The device according to  claim 1 , wherein
 the first detected member is biased and supported in one direction, and   the sensor detects the first detected member when the sheet is not present on the pressing tray regardless of the biasing state or the bias releasing state of the pressing tray, and generates a detection signal.   
     
     
         3 . The device according to  claim 1 , wherein
 the first detected member is biased and supported in one direction, and   the sensor detects the first detected member when the sheet is not present on the pressing tray in the biasing state of the pressing tray, and generates a detection signal.   
     
     
         4 . The device according to  claim 1 , wherein the sensor is set on a lower surface of the pressing tray. 
     
     
         5 . The device according to  claim 1 , further comprising a determining unit configured to determine, on the basis of a detection signal generated by the sensor, that the device is in a state in which the sheet is not present on the pressing tray or the bias releasing state of the pressing tray. 
     
     
         6 . The device according to  claim 5 , wherein the device includes a first sensor as the sensor that detects the first detected member and generates a first detection signal as the detection signal, and a second sensor as the sensor that detects the second detected member and generates a second detection signal as the detection signal. 
     
     
         7 . The device according to  claim 6 , wherein
 the first detected member is biased and supported in one direction, and   the first sensor detects the first detected member when the sheet is not present on the pressing tray regardless of the biasing state or the bias releasing state of the pressing tray, and generates the first detection signal.   
     
     
         8 . The device according to  claim 6 , wherein the first sensor and the second sensor are set on a lower surface of the pressing tray. 
     
     
         9 . The device according to  claim 6 , further comprising a determining unit configured to determine that the device is in the state in which the sheet is not present on the pressing tray when only the first detection signal is generated, determine that the device is in the state in which the sheet is not present on the pressing tray and the bias releasing state of the pressing tray when the first detection signal and the second detection signal are generated, and determine that the device is in a state in which the sheet is present and the bias releasing state of the pressing tray when only the second detection signal is generated. 
     
     
         10 . An image forming apparatus including a manual paper feed device configured to be retractable in an apparatus main body, comprising:
 a manual feed tray configured to stack a sheet;   a paper feeding roller configured to feed the sheet on the manual feed tray into an image forming unit;   a pressing tray configured to stack the sheet, rotatably supported with a first pivoting shaft as a first fulcrum and a downstream side of which in a conveying direction of the sheet is biased to the paper feeding roller side;   a bias releasing member configured to separate and hold the pressing tray in a direction opposed to the bias direction and release the biasing;   a sensor configured to detect at least one of presence or absence of the sheet on the manual feed tray and a bias releasing state of the pressing tray;   a switching member configured to switch a biasing state and the bias releasing state of the pressing tray, coupled to the bias releasing member;   a first detected member rotatably supported with a second pivoting shaft as a second fulcrum in contact with the sheet on the pressing tray, and provided in a position detectable by the sensor when the sheet is not present on the pressing tray;   a second detected member provided in a position detectable by the sensor when the pressing tray is in the bias releasing state;   a determining unit configured to determine a state of the manual paper feed device on the basis of a detection signal of the sensor; and   a notifying unit configured to notify a result of the determination by the determining unit.   
     
     
         11 . The apparatus according to  claim 10 , wherein
 the first detected member is biased and supported in one direction, and   the sensor detects the first detected member when the sheet is not present on the pressing tray regardless of the biasing state or the bias releasing state of the pressing tray, and generates the detection signal.   
     
     
         12 . The apparatus according to  claim 10 , wherein the sensor is set on a lower surface of the pressing tray. 
     
     
         13 . The apparatus according to  claim 10 , wherein the determining unit determines, on the basis of the detection signal generated by the sensor, that the manual paper feed device is in a state in which the sheet is not present on the pressing tray or the bias releasing state of the pressing tray. 
     
     
         14 . The apparatus according to  claim 10 , further comprising a registration sensor configured to detect the sheet conveyed from the manual feed tray to registration rollers, wherein
 the determining unit determines that the manual paper feed device shifts to a state in which the sheet is not present on the pressing tray when the registration sensor detects the sheet and the sensor generates the detection signal, and that the manual paper feed device is in the bias releasing state of the pressing tray when the registration sensor does not detect the sheet and the sensor generates the detection signal.   
     
     
         15 . The apparatus according to  claim 10 , wherein the apparatus includes a first sensor as the sensor that detects the first detected member and generates a first detection signal as the detection signal, and a second sensor as the sensor that detects the second detected member and generates a second detection signal as the detection signal. 
     
     
         16 . The apparatus according to  claim 15 , wherein
 the first detected member is biased and supported in one direction, and   the first sensor detects the first detected member when the sheet is not present on the pressing tray regardless of the biasing state or the bias releasing state of the pressing tray, and generates the first detection signal.   
     
     
         17 . The apparatus according to  claim 15 , wherein the first sensor and the second sensor are set on a lower surface of the pressing tray. 
     
     
         18 . The apparatus according to  claim 15 , wherein the determining unit determines that the manual paper feed device is in the state in which the sheet is not present on the pressing tray when only the first detection signal is generated, determines that the manual paper feed device is in the state in which the sheet is not present on the pressing tray and the bias releasing state of the pressing tray when the first detection signal and the second detection signal are generated, and determines that the manual paper feed device is in the bias releasing state of the pressing tray when only the second detection signal is generated. 
     
     
         19 . An image forming method comprising:
 generating a detection signal in at least one of a state in which the sheet is not present on a pressing tray of a manual paper feed device, that is biased to a paper feeding roller side with the sheet stacked thereon and a bias releasing state of the pressing tray;   determining, on the basis of the detection signal, at least one of the state in which the sheet is not present on the pressing tray and the bias releasing state of the pressing tray;   stopping driving of the paper feeding roller according to the determination; and   notifying a result of the determination.   
     
     
         20 . The method according to  claim 19 , wherein, when the detection signal includes a first detection signal indicating a state in which the sheet is not present on the pressing tray in the pressing tray biasing state, and a second detection signal indicating the bias releasing state of the pressing tray, it is determined on the basis of the detection signals that the manual paper feed device is in the state in which the recording sheet is not present on the pressing tray or the bias releasing state of the pressing tray.