JP2020033161A - Paper feeder and image formation device - Google Patents

Abstract

To provide a paper feeder which detects looseness of a wire to prevent reverse winding without deteriorating durability of the wire used for moving up or down a loading plate.SOLUTION: A paper feeder includes: a loading part for loading recording mediums; a hanging member which hangs the loading part; a rotary member which winds up the hanging member onto a winding part or releases the hanging member through rotation to move up or down the loading part; and detection means which detects looseness of the hanging member in the winding part. Upward movement or downward movement of the loading part is controlled by the rotary member according to a detection result of the detection means.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a sheet feeding device and an image forming device.

  2. Description of the Related Art As a sheet feeding device of an image forming apparatus, a sheet feeding device for continuously feeding a large number of sheets is known. A sheet stacking unit on which sheets provided in the sheet feeding device can be mounted is suspended by a wire, and the wire is wound around a winding pulley which is rotated in both forward and reverse directions by a lifting motor of the sheet stacking unit. The lifting and lowering of the sheet stacking unit is controlled by the rotation of a lifting motor.

  In the sheet feeding device configured as described above, if the sheet stacking unit cannot be lowered for some reason while the sheet stacking unit is being lowered, if the elevating motor continues to rotate, the wire is released from the pulley and slack occurs. . Thereafter, when the rotation continues further, the released wire starts to be wound again around the rotating pulley, and a reverse winding state occurs. When a reverse winding state occurs in the wire, the sheet stacking unit rises in spite of the fact that the elevating motor is rotating in a direction to open the wire (performing an operation of lowering the sheet stacking unit). Then, if the rotation is continued as it is, there is a problem that the sheet stacking portion comes into contact with the upper portion of the sheet feeding device.

  In order to avoid the reverse winding state as described above, for example, Patent Document 1 proposes a configuration in which a detection arm is brought into contact with a wire itself and a slack sensor disposed at the base of the detection arm detects slack of the wire. Have been.

JP 2009-184800 A

  However, in Patent Literature 1, since the detection arm is always in contact with the surface of the moving wire when measuring the slack of the wire, the detection arm and the wire are worn, and abnormal noise when the arm and the wire touch each other is generated. Problems will arise. Further, in the case of the configuration of Patent Document 1, the detection by the slack of the wire is possible only between the driven pulleys. For example, when an abnormality such as a broken wire occurs in another portion and the wire is not loose in the detecting portion. However, the abnormal state continues without detecting the slack. Further, since a detection arm is provided between the take-up pulley and the driven pulley for carrying the wire and a sensor is detected by the displacement of the arm, a space therebetween is sacrificed.

  The present invention has been made in view of the above problems, and has as its object to detect a slack in a wire without lowering the durability of the wire and prevent reverse winding.

  In order to solve the above problems, the present invention has the following configurations. That is, in the paper feeding device, a loading unit for loading a recording medium, a suspending member that suspends the loading unit, and the rotation of the suspension unit to wind or release the hanging member. A rotating member that raises and lowers the loading unit, and a detecting unit that detects slack of the hanging member in the winding unit, and the loading unit that is configured by the rotating member according to a detection result of the detecting unit. Is controlled.

  ADVANTAGE OF THE INVENTION According to this invention, loosening of a wire can be detected, without reducing the durability of a wire, and reverse winding can be prevented.

FIG. 2 is a diagram illustrating a schematic configuration of an image forming apparatus and a sheet feeding apparatus according to the embodiment. FIG. 3 is a schematic diagram illustrating a state where a sheet storage unit is pulled out from the sheet feeding device according to the embodiment. FIG. 2 is a diagram illustrating a schematic configuration of a sheet storage unit according to the embodiment. FIG. 4 is a diagram for explaining details of a lifting mechanism of the sheet storage unit according to the embodiment. The figure for demonstrating the load direction with respect to a winding pulley. The figure for demonstrating the state in which a foreign material exists in the lower part of a loading plate. The figure for demonstrating the winding state of the wire of the winding pulley at the time of abnormal operation. FIG. 4 is a detailed view of a winding pulley looseness detection mechanism according to the embodiment. FIG. 4 is a detailed view of a winding pulley looseness detection mechanism according to the embodiment. 5 is a time chart showing an output signal of an optical sensor during rotation of a take-up pulley. FIG. 4 is a diagram illustrating a control configuration example of a control unit according to the embodiment. 4 is a flowchart illustrating a control flow according to the embodiment. FIG. 5 is a detailed view of a winding pulley looseness detection mechanism according to another embodiment of the present invention. FIG. 5 is a detailed view of a winding pulley looseness detection mechanism according to another embodiment of the present invention.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. Here, an electrophotographic image forming apparatus will be described as an example, but an image forming apparatus of another type may be used.

[Device configuration]
FIG. 1 shows a schematic configuration of an image forming apparatus 1 and a sheet feeding device 2 in the present embodiment. FIG. 1A illustrates a state in which the sheet feeding device 2 is mounted on the image forming apparatus 1, and FIG. 1B illustrates a state in which the sheet feeding device 2 is separated from the image forming apparatus 1. I have.

  Above the image forming apparatus 1, a laser scanner 11 and a mirror 12 for exposing the photosensitive drum 10 to write an electrostatic latent image are provided. The image forming apparatus 1 converts the received image data into write image data, transmits the write image data to the laser scanner 11, and forms an electrostatic latent image on the photosensitive drum 10 according to the write image data.

  The image forming unit includes an optical system including a photosensitive drum 10, a laser scanner 11, and a mirror 12, a charger 13, a developing unit 14, a transfer roller 15, and a cleaner 16. The charger 13 uniformly charges the surface of the photosensitive drum 10. The laser irradiated by the laser scanner 11 is deflected by the mirror 12 to the photosensitive drum 10 and draws an electrostatic latent image on the surface of the photosensitive drum 10 charged by the charger 13. The developing device 14 develops the electrostatic latent image on the photosensitive drum 10 formed by the laser from the laser scanner 11 into a toner image transferred to a sheet S as a recording medium such as paper. The transfer roller 15 transfers the toner image developed on the surface of the photosensitive drum 10 to the sheet S. The cleaner 16 removes the toner remaining on the photosensitive drum 10 after transferring the toner image.

  On the downstream side of the image forming unit, a transport unit 17 for transporting the sheet S to which the toner image has been transferred, and a fixing unit 18 for fixing the toner image on the sheet S transported by the transport unit 17 are provided. Is provided. Further, a discharge roller 19 for discharging the sheet S, on which the toner image is fixed by the fixing device 18, from the image forming apparatus 1 to the outside is provided downstream of the fixing device 18. A discharge sheet stacking tray (hereinafter, referred to as a discharge tray) 20 for receiving the sheet S discharged by the discharge roller 19 is provided outside the upper portion of the image forming apparatus 1.

  The cassette sheet feed trays 30a to 30d are provided so as to be located at the most upstream position (the most upstream position in the transport direction) in sheet transport, and can store a predetermined number of sheets S. Here, an example in which four cassette feed trays 30a to 30d are provided is shown, but the present invention is not limited to this. Further, the cassette paper feed tray 30 may store sheets of different sizes. On a side surface of the image forming apparatus 1, a manual paper feed unit 30e for manually inserting a sheet is provided.

  The image forming apparatus 1 is provided with four cassette sheet feed roller pairs 31a to 31d that feed sheets from the respective cassette sheet feed trays 30a to 30d below the image forming apparatus 1. Further, the image forming apparatus 1 is provided with a manual paper feed roller pair 31e for feeding paper from a manual paper feed unit 30e provided on a side surface. Further, the paper feeding device 2 is detachably mounted below the manual paper feeding unit 30e.

  The paper feeding device 2 is configured to be able to support the stacking of relatively large-capacity sheets. The sheet feeding device 2 feeds the stacked and stored sheets S one by one by a sheet feeding deck roller 31f. The sheet S picked up by the cassette sheet feeding roller pairs 31a to 31d, the manual sheet feeding roller pair 31e, and the sheet feeding deck roller 31f is conveyed downstream in the conveyance direction through the vertical conveyance path 33 by the drawing roller pairs 32a to 32d. You. A registration roller pair 34 is provided at the most downstream position of the vertical conveyance path 33, where final registration of skew of the sheet, timing of image writing in the image forming unit, and timing of sheet conveyance are performed. Further, a path for reversing the sheet is also provided on the transport path in the image forming apparatus 1.

  Further, as shown in FIG. 1B, when the sheet feeding device 2 is separated from the image forming apparatus 1 due to jam processing or the like, the sheet feeding device 2 is housed inside the sheet feeding device 2 in FIG. The sheet feeding device 2 is separated from the image forming apparatus 1 along the detachable rail 35. When the image forming apparatus 1 and the sheet feeding apparatus 2 are separated or approached, it is possible to perform the operation by a user.

(Paper feeder)
Next, the configuration of the sheet feeding device 2 will be described with reference to FIG. FIG. 2 shows a state where the sheet storage unit 3 is pulled out from the sheet feeding device 2 according to the present embodiment.

  The sheet feeding device 2 includes a sheet storage unit 3 including a stacking plate 36 (sheet stacking unit), which is a stacking unit that can stack and move the sheets S up and down, and a pair of frames 37. The sheet storage unit 3 is connected to the left and right sides inside the sheet feeding device 2 and is slidably supported by an open / close rail 38. In FIG. 2, the sheet storage unit 3 may be configured to be capable of stacking a plurality of types of sheets. In this case, a partition plate (not shown) that can slide according to the size of the stacked sheets S is provided. It may be provided on the loading plate 36. The paper feeder 2 is provided with a storage open / close switch 39. When the user presses the storage opening / closing switch 39, the sheet storage unit 3 is pushed out by an urging member (not shown) to a drawable position where the sheet storage unit 3 can be pulled out to the near side along the opening / closing rail 38. It is. As a result, the sheet storage unit 3 can be pulled out and easily moved to the sheet replenishable position.

(Seat storage section)
Next, a detailed configuration of the sheet storage unit 3 of the sheet feeding device 2 will be described with reference to FIG. FIG. 3 is a schematic configuration diagram of the sheet storage unit 3 according to the present embodiment as viewed from the moving direction of the opening / closing rail 38.

  The loading plate 36 is configured to move up and down between a pair of right and left frames 37. The loading plate 36 is suspended at one of the connection points near four corners by one end of a wire 40 as a suspension member. The other end of the wire 40 is connected to a take-up pulley 42 provided before and after the sheet storage unit 3 via a relay roller 41 rotatably provided above the sheet storage unit 3. The loading plate 36 rises when the wire 40 is wound by the winding pulley 42, and moves down when the wire 40 is fed (opened) by the winding pulley 42.

  Further, a paper surface detection sensor 43 for detecting the paper surface (uppermost portion) of the sheet S stacked on the raised stacking plate 36 is provided at an upper portion on one side of the frame 37. When the sheet surface sensor 43 detects the sheet surface (uppermost portion) of the sheet S stacked on the stacking plate 36 that has risen, the stacking plate 36 stops being lifted. Similarly, a lower limit sensor 44 for detecting that the loading plate 36 has been lowered to the lowermost end is provided at a lower portion on one side of the frame 37. When the lower limit sensor 44 detects the lowered loading plate 36, the lowering of the loading plate 36 is stopped.

(Elevating mechanism)
A configuration example of the lifting mechanism of the sheet storage unit 3 according to the present embodiment will be described with reference to FIG. FIG. 4 is a diagram illustrating details of a configuration example of the lifting mechanism of the sheet storage unit 3 according to the present embodiment.

  The take-up pulley 42 is fixed to a shaft 45, and the shaft 45 is connected so as to interlock with the driving of a lifting / lowering motor 56 (described later) functioning as a rotating member. When the take-up pulley 42 is rotated in the take-up direction by the drive of the elevating motor 56, the wire 40 is taken up by the take-up pulley 42 and connected to the wire 40 at connection points A, B, C, and D. The plate 36 rises. Here, an example in which there are four connection points is shown, but the invention is not limited to this.

  When the drive of the elevating motor 56 is reversed and the winding pulley 42 is rotated in the unwinding direction, the wire 40 is unreeled from the winding pulley 42 and descends by the weight of the loading plate 36. The rotation speed of the lifting motor 56 in the winding direction and the rotation speed in the feeding direction may be the same or different. In FIG. 4, rotation in the clockwise direction corresponds to rotation in the winding direction, and rotation in the counterclockwise direction corresponds to rotation in the payout direction.

  As shown in FIGS. 5A and 5B, the wire 40 wound by the winding pulley 42 is always loaded by the weight of the loading plate 36 and the loaded sheet S, and the lifting of the loading plate 36 A load exists in the payout direction of the wire 40 during both downward rotations. The load here corresponds at least to the weight of the loading plate 36. FIG. 5A shows a winding direction and a load direction when the wire 40 is wound in the normal operation. FIG. 5B shows the unwinding direction and the load direction when the wire 40 is unwound in the normal operation.

  However, as shown in FIG. 6, when foreign matter G or the like is present below the loading plate 36, the loading plate 36 is prevented from descending, and the loading plate 36 does not descend on the way. FIG. 6 shows a state in which the foreign matter G is present below the loading plate 36. In this case, the winding pulley 42 keeps feeding the wire 40 until the lower limit sensor 44 provided below the sheet storage unit 3 detects the stacking plate 36.

  Further, the lower portion of the loading plate 36 is supported by the foreign matter G, and the load applied to the wire 40 is lost (decreased). Therefore, as shown in FIG. Begins to sag. When this state continues, as shown in FIG. 7B, all the wires 40 wound around the take-up pulley 42 are fed out. Then, in spite of the operation of unwinding the wire 40, the winding pulley 42 is in a reverse winding state in which the winding of the wire 40 can be started in a direction opposite to the normal direction. FIG. 7A shows a state where the wire 40 is drawn out during an abnormal operation. FIG. 7B shows a state in which the wire 40 is continuously drawn out from the state of FIG. That is, in FIG. 7B, the rotation direction of the winding pulley 42 is the same as that of FIG. 5B, but the feeding and winding are reversed.

(Detection mechanism)
Here, a detection mechanism for detecting the above-described looseness and the reverse winding state in the present embodiment will be described with reference to FIGS. 8 and 9. FIG. 8 shows a state in which the wire 40 is wound around the winding pulley 42 during a normal operation. FIG. 9 shows a state where the wire 40 is loosened from the winding pulley 42. FIGS. 8A and 9A are perspective views around the take-up pulley 42. FIGS. 8B and 9B are views of the periphery of the take-up pulley 42 as viewed from the side of the sheet feeding device 2. FIGS. 8C and 9C are cross-sectional views of the periphery of the take-up pulley 42 as viewed from the side of the sheet feeding device 2. FIGS. 8D and 9D are enlarged views of a part of the cross section when the periphery of the take-up pulley 42 is viewed from the side of the sheet feeding device 2.

  The take-up pulley 42 in the present embodiment is rotatable around a shaft 45 and engages with a parallel pin 46 integral with the shaft 45 to rotate with the driving of the elevating motor 56.

  The winding pulley 42 is provided with a detection member 47 engaged with a part thereof. The detection member 47 is configured to be able to stand (turn) in the normal direction of the winding pulley 42 with the rotation fulcrum 47S as a fulcrum. The detecting member 47 has a negative pressure member 48 attached to the other end of the rotation fulcrum 47S, and operates according to a load (tightening / slack) applied to the winding pulley 42 by the wire 40. Specifically, when the wire 40 is wound around the winding pulley 42, as shown in FIG. 8D, a winding force 40F generated by winding the wire 40 causes a compressive force 48F of the negative pressure member 48. , The detection member 47 is stored inside the take-up pulley 42. On the other hand, when the wire 40 is loose from the take-up pulley 42, as shown in FIG. 9D, the winding force 40F of the wire 40 is lower than the compression force 40F of the negative pressure member, so that the detection member 47 rotates. It stands on the fulcrum 47S in the normal direction of the winding pulley 42. As the negative pressure member 48, for example, a spring can be used, but the invention is not limited to this. Further, in the present embodiment, the configuration example has been described in which the detection member 47 rotates around the rotation fulcrum 47S, but the invention is not limited thereto. For example, the configuration may be such that the member protrudes as the load on the winding pulley 42 decreases.

  As shown in FIG. 8, an optical sensor 49 is provided on an outer peripheral portion of the winding pulley 42. The optical sensor 49 includes a light emitting unit 49L and a light receiving unit 49P. When the light emitted from the light emitting unit 49L cannot be detected by the light receiving unit 49P, the output of the optical sensor 49 is turned off. The optical sensor 49 is configured such that a part of the trajectory of the rotation of the detection member 47 about the shaft 45 (the light blocking portion 47R provided on the detection member 47) passes between the light emitting portion 49L and the light receiving portion 49P of the optical sensor 49. It is constituted so that.

  As shown in FIGS. 8C and 9C, when the detection member 47 is rotated about the shaft 45 as a rotation center, a part (light-shielding portion 47R) of the optical sensor 49 includes the light-emitting portion 49L and the light-receiving portion 49P. Are arranged in a direction to block the light. The detection result of the optical sensor 49 is transmitted to a CPU 52 (described later) that controls the operation of the sheet feeding device 2. Although FIGS. 8 and 9 show an example in which the optical sensor 49 is disposed below the take-up pulley 42, the present invention is not limited to this. For example, it may be arranged above or beside the outer periphery of the winding pulley 42.

  When the wire 40 is wound or unwound in the normal state, the winding pulley 42 rotates clockwise (clockwise in the figure) as shown in FIG. 8A under the influence of the load due to the stacking plate 36 and the stacked sheets S. Load. As a result, the wire 40 is wound around the winding pulley 42, and the winding force 40F of the wire 40 exceeds the force of the negative pressure member 48F that pushes up the detection member 47. Therefore, as shown in FIG. 47 is stored as a part of the shape of the winding pulley 42.

  When the detection member 47 holds a state in which a part of the shape of the take-up pulley 42 is configured, the signal L output from the light emitting unit 49L of the optical sensor 49 is not blocked by the detection member 47 (the light shielding unit 47R). The light is received by the light receiving unit 49P. At this time, the output of the optical sensor 49 is ON. In this case, the load on the winding pulley 42 is applied in a normal direction, and it can be determined that the wire 40 is normally wound or unwound.

  On the other hand, when the foreign matter G exists below the loading plate 36 and the lowering of the loading plate 36 is hindered, the load due to the loading plate 36 and the loaded sheets S disappears (or decreases) as described above, and the winding is performed. The load on the pulley 42 is eliminated (or reduced). By eliminating the load on the winding pulley 42, the winding force of the wire 40 wound on the winding pulley 42 is reduced. Thereafter, when the winding of the winding pulley 42 further continues, as shown in FIG. 9C, the wire 40 is fed out from the winding pulley 42 and starts to loosen. When the wire 40 is loosened, the detection member 47 stored in the take-up pulley 42 stands up about the rotation fulcrum 47S by the force of the negative pressure member 48.

  When the take-up pulley 42 continues to be wound with the detection member 47 standing up, the trajectory of the detection member 47 (light-shielding portion 47R) passes between the light-emitting portion 49L and the light-receiving portion 49P of the optical sensor 49. At this time, the signal L (light) output from the light emitting unit 49L of the optical sensor 49 is blocked by a part of the detecting member 47 (the light shielding unit 47R), and is not received by the light receiving unit 49P. At this time, the output of the optical sensor 49 is turned off. At the moment when the output of the optical sensor 49 is turned off, the detecting member 47 is released from the winding force of the wire 40 and stands up, that is, it is determined that the wire 40 has been fed out from the winding pulley 42 and has been bent to be in a reverse winding state. can do.

(Output signal of optical sensor)
The output signal of the optical sensor 49 according to the winding state of the wire 40 will be described with reference to FIG. FIG. 10 shows an output signal of the optical sensor 49 while the take-up pulley 42 is rotating. FIG. 10A shows an output signal of the optical sensor 49 in a state where the wire 40 is normally wound or unwound. FIG. 10B shows an output signal of the optical sensor 49 in a state where the reverse winding state has occurred.

  In a state where the wire 40 is normally wound or unwound, as shown in FIG. 10A, while the winding pulley 42 is rotating, the optical sensor 49 always receives the signal L from the light emitting unit 49L as the light receiving unit. Since 49P is detected, an ON signal is constantly output. On the other hand, when the reverse winding state occurs, as shown in FIG. 9C, the detection member 47 (the light shielding unit 47R) shields the signal L from the light emitting unit 49L during the rotation of the winding pulley 42. , The light receiving unit 49P does not detect, and the output signal of the optical sensor 49 switches to OFF.

  In the present embodiment, it is determined from these output results whether or not the wire 40 is normally wound or unwound by the winding pulley 42. FIG. 10 shows an example of a signal for two rotations of the elevating motor 56 when the loading plate 36 is lowered. However, the rotation speed when the loading plate 36 descends from the highest position to the lowest position is not limited to the above. That is, the output (detection result) of the optical sensor 49 is always monitored when the elevating motor 56 is operating during the descent. Further, the light emitting section 49L of the optical sensor 49 may be configured to emit light only when the loading plate 36 is lowered. Further, in the example of FIG. 10, the output of the optical sensor 49 is turned off when the light is blocked by the light shielding unit 47 </ b> R, and the output is turned on when the light is not blocked. However, the reverse is also possible. .

(Control configuration)
The control configuration of the present embodiment will be described with reference to FIG. FIG. 11 is a block diagram illustrating the concept of the control configuration according to the present embodiment. The CPU 52 controls the operation of the sheet feeding device 2. The CPU 52 receives signals from various sensors and drives a lifting motor 56 that rotates the take-up pulley 42 based on the various signals. Further, the CPU 52 performs various display controls on the display unit 55. Note that the CPU 52 and the display unit 55 may be provided on the image forming apparatus 1 side, or may be provided on the sheet feeding apparatus 2 side. Further, the display unit 55 may be a display, or may be configured by an LED or the like.

  When the CPU 52 receives a signal indicating that the open / close switch 53 has been pressed, the motor drive circuit 54 drives the lifting / lowering motor 56, and the wire 40 is pulled up by the winding pulley 42 provided on the shaft 45 linked to the lifting / lowering motor 56. It is paid out. Accordingly, the loading plate 36 is lowered until the lower limit sensor 44 detects the loading plate 36. Thereafter, the sheet storage unit 3 is pulled out and moves to a sheet replenishable position.

  The CPU 52 monitors whether or not the winding pulley 42 normally draws out the wire 40 based on the output result of the optical sensor 49. When the CPU 52 determines that the winding pulley 42 has not normally fed the wire 40, the CPU 52 determines that the foreign matter G has entered the lower portion of the loading plate 36, and notifies the display unit 55 that the foreign matter has been detected. Display. The content of the notification here is not particularly limited, but may be, for example, a message requesting removal of the foreign matter G or lighting indicating an error.

  When the sheet S is replenished to the sheet storage unit 3 and the sheet storage unit 3 is stored in the sheet feeding device 2, the motor drive circuit 54 drives the elevating motor 56 and is provided on the shaft 45 that is interlocked with the elevating motor 56. The wire 40 is wound by the winding pulley 42. Accordingly, the stacking plate 36 is raised until the paper surface detection sensor 43 detects the uppermost surface of the sheet S. Thereafter, the sheet storage unit 3 is moved to the sheet feeding position, and the state shifts to the standby state.

[Processing flow]
Next, a control flow of the CPU 52 of the present embodiment will be described with reference to FIG. FIG. 12 is a flowchart illustrating a control flow of the CPU 52 in the present embodiment. For example, the CPU 52 executes the present processing flow by reading and executing a program stored in a storage unit (not shown). When the open / close switch 53 of the sheet storage unit 3 is pressed, this processing flow is started.

  In S101, the CPU 52 drives the elevating motor 56 by the motor driving circuit 54 to rotate the shaft 45 in a direction to lower the stacking plate 36. Thereby, the wire 40 is fed out by the winding pulley 42 provided on the shaft 45, and the lowering of the loading plate 36 is started.

  In S102, CPU 52 determines whether or not stacking plate 36 has reached the lower limit position based on the detection result of lower limit sensor 44. When it is determined that the loading plate 36 is not at the lower limit position (NO in S102), the process proceeds to S103, and when it is determined that the loading plate 36 is at the lower limit position (YES in S102), the process proceeds to S106.

  In S103, the CPU 52 determines whether or not the winding pulley 42 normally draws out the wire 40 based on the detection result of the optical sensor 49. This determination is made based on the change in the output of the optical sensor 49 described with reference to FIGS. When it is determined that the wire 40 is normally extended (YES in S103), the process returns to S102, and the process is repeated. On the other hand, when it is determined that the wire 40 has not been normally fed (NO in S103), the process proceeds to S104.

  In S104, the CPU 52 determines that the take-up pulley 42 is in the reverse winding state, and stops the lowering of the loading plate 36. That is, the rotation of the elevating motor 56 is stopped by the motor drive circuit 54.

  In S105, CPU 52 causes display unit 55 to display a foreign object detection notification. The display content here may display, for example, a message requesting removal of a foreign substance or causing a failure in lowering the loading plate 36. Then, this processing flow ends.

  In S106, the CPU 52 stops the lowering of the stacking plate 36 by stopping the rotation of the elevating motor 56 via the motor drive circuit 54.

  In S107, the CPU 52 unlocks the sheet storage unit 3, pushes the sheet storage unit 3 to a position where the sheet storage unit 3 can be pulled out by an urging member (not shown), and pulls out the sheet storage unit 3 from the sheet feeding device 2 as shown in FIG. To be able to move to the sheet supply position. In this state, the user can supply the sheet S to the sheet storage unit 3.

  In S108, CPU 52 determines whether or not sheet storage unit 3 is stored in sheet feeding device 2 and locked. When it is determined that the sheet storage unit 3 is stored in the sheet feeding device 2 and locked (YES in S108), the process proceeds to S109. If it is determined that it has not been locked (NO in S108), it waits until it is locked.

  In S109, the CPU 52 drives the elevating motor 56 by the motor driving circuit 54 to rotate the shaft 45 in a direction in which the loading plate 36 is raised. Thereby, the wire 40 is wound by the winding pulley 42 provided on the shaft 45, and the ascent of the loading plate 36 is started.

  In S110, the CPU 52 determines whether or not the uppermost surface of the sheet S or the stacking plate 36 has reached the sheet feeding position based on the detection result of the sheet surface detection sensor 43. When it is determined that the uppermost surface of the sheet S or the stacking plate 36 has reached the sheet feeding position (YES in S110), the process proceeds to S111. If it is determined that the sheet feeding position has not been reached (NO in S110), the lifting operation of the stacking plate 36 is continued until the sheet feeding position is reached.

  In S111, the CPU 52 stops the driving of the elevating motor 56 and stops the lifting of the stacking plate 36. In this case, the lifting of the loading plate 36 has been completed normally. Then, this processing flow ends.

  As described above, according to the present embodiment, unlike the related art, the detecting means does not contact the wire itself to apply friction or load, and thus it is possible to detect the slack of the wire without lowering the durability. Further, reverse winding of the wire in the winding pulley can be prevented. Further, it is possible to detect the presence of a foreign substance that has entered below the loading plate 36.

[Other Embodiments]
In the above-described embodiment, the optical sensor 49 is provided near the take-up pulley 42, and the behavior of the take-up pulley 42 is monitored by the optical sensor 49 to determine whether or not there is a foreign substance below the loading plate 36. . As another embodiment of the present invention, a configuration in which a pressure-sensitive switch 50 as a pressure-sensitive sensor is arranged near the take-up pulley 42 as shown in FIG. In this configuration, the pressure-sensitive switch 50 is pressed (applied pressure) by the pressing member 47A, which is a part of the detection member 47 opened by the slack of the wire 40, and the foreign matter is placed below the loading plate 36. It is determined whether or not there is. The timing at which the pressure-sensitive switch 50 is pressed is the same as that described with reference to FIG.

  Further, as another embodiment of the present invention, a configuration using a wireless transmission type pressure-sensitive switch between the take-up pulley 42 and the detection member 47 as shown in FIG. 14 may be employed. In this configuration, the transmitting unit 51A is provided on the winding pulley 42 side, and the receiving unit 51B is installed outside (around) the winding pulley 42. Then, the transmission unit 51A detects a change in the position of the detection member 47 that has been opened due to the looseness of the wire 40, and transmits a signal of the sensor using a wireless signal. The receiving unit 51B installed outside the take-up pulley 42 can determine whether there is a foreign substance below the loading plate 36 by receiving the signal transmitted from the transmitting unit 51A. The timing of signal transmission and reception by the wireless transmission type pressure-sensitive switch is the same as that described with reference to FIG.

  According to the present invention, there is provided a process for supplying a program for realizing one or more functions of the above-described embodiments to a system or an apparatus via a network or a storage medium, and one or more processors in a computer of the system or the apparatus reading and executing the program. But it is feasible. Further, it can also be realized by a circuit (for example, an ASIC) that realizes one or more functions.

36 loading plate, 40 wire, 41 pulley, 42 take-up pulley, 43 paper surface detection sensor, 44 lower limit sensor, 47 detection member, 48 negative pressure member, 49 optical sensor, 52 CPU 54: motor drive circuit, 55: display unit, 56: elevating motor

Claims (16)

A loading unit for loading a recording medium,
A suspending member for suspending the loading unit,
A rotation member that raises and lowers the stacking unit by winding or releasing the hanging member to a winding unit by rotation,
Detecting means for detecting the slack of the hanging member in the winding section,
The sheet feeding device according to claim 1, wherein the lifting and lowering of the loading section by the rotating member is controlled according to a detection result of the detection unit.   2. The sheet feeding device according to claim 1, wherein, when the loading unit is lowered, the lowering of the loading unit by the rotating member is stopped when the detecting unit detects the slack of the hanging member. 3. The detection means,
A first detection member that is provided on the winding unit and that operates in response to a change in load on the winding unit from the hanging member during rotation;
3. The sheet feeding device according to claim 1, further comprising a second detection member provided around the winding unit and configured to detect an operation of the first detection member. 4. The first detection member is configured to protrude from the winding unit when a load on the winding unit from the hanging member during rotation decreases.
4. The sheet feeding device according to claim 3, wherein the second detection unit is configured to detect the first detection member protruding from the winding unit. 5. The second detection means includes an optical sensor,
The looseness of the hanging member is detected when the first detecting member protruding from the winding unit detects that light emitted by the optical sensor is blocked. A paper feeder according to claim 1. The second detection means is configured to include a pressure-sensitive sensor,
5. The paper feeder according to claim 4, wherein the first detection member protruding from the winding unit detects looseness of the hanging member when the pressure-sensitive sensor detects pressing. . The first detection member is configured to transmit a wireless signal when a load on the winding unit from the hanging member during rotation decreases.
The paper feeding device according to claim 3, wherein the second detection unit is configured to receive a wireless signal transmitted from the first detection member.   The sheet feeding device according to claim 3, wherein the load on the winding unit includes at least a load due to a weight of the loading unit. An image forming apparatus including a control unit and a sheet feeding device,
The paper feeding device,
A loading unit for loading a recording medium,
A suspending member for suspending the loading unit,
A rotation member that raises and lowers the stacking unit by winding or releasing the hanging member to a winding unit by rotation,
Detecting means for detecting the slack of the hanging member in the winding section,
The image forming apparatus according to claim 1, wherein the control unit controls elevation of the loading unit by the rotating member according to a detection result of the detection unit.   The apparatus according to claim 9, wherein the control unit stops lowering the loading unit by the rotating member when the detecting unit detects loosening of the hanging member when the loading unit is lowered. Image forming device. The detection means,
A first detection member that is provided on the winding unit and that operates in response to a change in load on the winding unit from the hanging member during rotation;
The image forming apparatus according to claim 9, further comprising a second detection member provided around the winding unit and configured to detect an operation of the first detection member. The first detection member is configured to protrude from the winding unit when a load on the winding unit from the hanging member during rotation decreases.
The image forming apparatus according to claim 11, wherein the second detection unit is configured to detect the first detection member protruding from the winding unit. The second detection means includes an optical sensor,
13. The slack of the hanging member is detected when detecting that the light emitted from the optical sensor is blocked by the first detection member protruding from the winding unit. An image forming apparatus according to claim 1. The second detection means is configured to include a pressure-sensitive sensor,
13. The image forming apparatus according to claim 12, wherein the first detecting member protruding from the winding unit detects looseness of the hanging member when the pressure-sensitive sensor detects pressing. . The first detection member is configured to transmit a wireless signal when a load on the winding unit from the hanging member during rotation decreases.
The image forming apparatus according to claim 11, wherein the second detecting unit is configured to receive a wireless signal transmitted from the first detecting member.   16. The control unit according to claim 9, wherein when the loading unit is lowered, the control unit notifies the display unit when the detection unit detects looseness of the hanging member. Image forming apparatus.