JP2015202945A - Paper feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding device which can stably feed sheets until the sheet at the bottom end of loaded sheets while preventing deformation from occurring in the loaded sheets.SOLUTION: A paper feeding device 30 for successively feeding sheets from the uppermost surface of sheets that are loaded on a loading surface 36u by a conveyance roller comprises: rollers 52 that are provided on the loading surface 36u in such a manner that they can be switched between a projected position U in which they are in contact with a sheet at the lowermost surface of the loaded sheets and are driven to rotate, and a retracted position L in which they are not in contact with the sheet at the lowermost surface; roller position switching means 54 for switching the position of the rollers 52 to the projected position U or the retracted position L; sheet loading amount detection means 60 for detecting the loading amount of sheets loaded on the loading surface 36u; and an arithmetic processing part for controlling the roller position switching means 54 in such a manner that it makes the projection members retract to the retracted position L when the sheet loading amount detected by the sheet loading amount detection means 60 is greater than a predetermined loading amount and makes the rollers 52 project into the projected position U when the sheet loading amount is not greater than the predetermined loading amount.

Description

  The present invention relates to a paper feeding device that feeds paper from a top surface among papers stacked on a stacking surface by a conveyance roller.

  The present invention relates to a paper feeding device that supplies a recording medium loaded in a paper feeding tray to a conveyance path of an image forming apparatus.

  2. Description of the Related Art Conventionally, an image forming apparatus is provided with a paper feeding device having a paper feeding tray for stacking and storing printing paper. In this paper feeding device, a bundle of recording media of a predetermined size is stacked, and the uppermost recording medium is picked up by a paper feeding device such as a pickup roller, and an image is formed from the paper feeding tray through a transport path. It is designed to be sent to the department.

  In such a paper feed tray, a structure in which a paper feed table arranged at the bottom of the paper feed tray moves up and down according to the remaining amount of the recording medium is common. Specifically, in the paper feed tray, the recording medium is raised up to the height of the supply position of the transport path, and the stacked uppermost recording medium is sent out by the paper feeding means. Then, as the paper feeding operation proceeds, the paper feed table is raised to maintain a position where the pickup operation by the pickup roller can be performed.

  By the way, in such a paper feeding device, the recording paper can be easily replenished to the paper feeding tray, and the last one (the bottommost one) stored in the paper feeding tray can be fed well. Is desirable. As a countermeasure, for example, in Patent Document 1, a rotation roller (sliding roller) that comes into contact with the rear end of the recording paper in the paper feed tray is provided so that the recording paper is supplied to the paper feed tray. A bundle of recording paper is guided to the back of the tray by rotating the rotating roller under its own weight, and the recording paper can easily slide on the bottom plate of the paper feeding tray even if it is the last sheet in the paper feeding tray. Proposed.

JP-A-8-231058

  However, in Patent Document 1, since the lower surface of the recording paper loaded on the paper feed tray is always in contact with the rotating roller, the recording paper is deformed such as wrinkles or undulations when the time stored in the paper feeding tray becomes long. Will occur.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a paper feeding device that can stably feed paper up to the bottom of the stack while preventing deformation of the stacked paper. To do.

  In order to achieve the above object, a first feature of the paper feeding device according to the present invention is that in the paper feeding device that feeds paper from the uppermost paper among the papers stacked on the stacking surface by a conveying roller, the paper is On the stacked stacking surface, a projecting member provided so as to be switchable between a projecting position that contacts and rotates following the stacked bottom sheet and a retracted position that does not contact the bottom sheet, and the projecting position Detected by a projecting member position switching means for switching the position of the projecting member to the retracted position, a paper stacking amount detecting means for detecting the stacking amount of the paper stacked on the stacking surface, and the paper stacking amount detecting means. The protruding member position switching means is controlled so that the protruding member is retracted to the retracted position when the sheet loading amount is larger than the predetermined loading amount, and the protruding member is protruded to the protruding position when the sheet loading amount is less than the predetermined loading amount. Control means; It lies in the fact that with.

  A second feature of the paper feeding device according to the present invention is that the protruding member is a rotating body that is rotatable in a paper feeding direction of a sheet fed by the transport roller, and rotates the rotating body. A driving unit is further provided, and the control means controls the rotating body driving unit so as to rotate the rotating body when the rotating body is protruded to the protruding position.

  According to the first feature of the paper feeding device according to the present invention, the projecting member can be switched between a projecting position that contacts the stacked bottom sheet and a retracted position that does not contact the bottom sheet, When it is not necessary to position the protruding member at the protruding position, the protruding member can be set to the retracted position, so that it is possible to stably feed the sheets up to the lower end of the stack while preventing deformation of the stacked sheets. .

  According to the second feature of the sheet feeder according to the present invention, the control means controls the rotating body drive unit to rotate the rotating body when the rotating body is protruded to the projecting position. Thus, it is possible to reliably feed up to the last one of the printed sheets.

1 is a front view illustrating a configuration of a printing apparatus according to a first embodiment. 1 is a front view illustrating a configuration of a sheet feeding device according to a first embodiment. FIG. 3 is a front view illustrating the supply of recording paper to the paper feeding device according to the first embodiment. FIG. 3 is a front view showing that the last sheet of recording paper loaded is fed by the paper feeding device of the first embodiment. It is a perspective view for demonstrating the paper feed stand of the paper feeder of 1st Embodiment. FIG. 4A is a diagram illustrating a sheet stacking amount detection unit of the sheet feeding device according to the first embodiment. FIG. It is front sectional drawing which shows the state which exists. It is a perspective view explaining the roller position switching means which switches a roller to a protrusion position and a retracted position in the paper feeder of the second embodiment. It is a front view explaining the roller position switching means which switches a roller to a protrusion position and a retracted position in the paper feeder of the second embodiment.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In the second and following embodiments, the same components as those described in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In addition, it should be noted that the drawings are schematic and the dimensional ratios and the like are different from actual ones. Therefore, specific dimensional ratios and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  The following embodiments are exemplifications for embodying the technical idea of the present invention, and the embodiments of the present invention are described below in terms of the material, shape, structure, arrangement, etc. of the components. It is not something specific. The embodiments of the present invention can be implemented with various modifications without departing from the scope of the invention.

  In the following description, any size paper can be applied. In the following embodiment, an example of printing by ink jet will be described, but printing may be performed by other methods such as stencil printing, and the printing format is not particularly limited in the present invention.

[First Embodiment]
First, the first embodiment will be described.

(Overall configuration of printing device)
FIG. 1 is a front view showing the configuration of the printing apparatus according to the present embodiment, and shows an outline of a printing paper conveyance path. In the present embodiment, the printing apparatus 10 includes a plurality of ink heads on which a number of nozzles are formed, discharges black or color ink from each of the ink heads, performs printing in units of lines, and records on the conveyance belt 17. An inkjet line color printer that forms a plurality of images on top of each other will be described as an example.

  As shown in FIG. 1, the printing apparatus 10 is an apparatus that forms an image on the surface of a sheet transported on an annular transport path. The transport path includes a paper feed system transport path FR that supplies the paper, A general path CR from the system transport path FR through the head unit 11 to the paper discharge path DR and a reverse path SR branched and connected to the normal path CR are roughly configured.

  In the paper feed path FR, the paper S fed from one of the side paper feed trays 12 and the paper feed trays 13 (13a to 13d) is a registration that is a reference position of the leading portion of the paper S. Guided to part R. A head unit 11 having a plurality of print heads is provided on the conveyance direction side of the registration unit R, and the sheet S is a speed determined by printing conditions by a conveyance belt 17 provided on the opposite surface of the head unit 11. The image is formed line by line with the ink ejected from each print head while being conveyed.

  In the normal path CR, the conveyor belt 17 is wound around the driven roller 16a and the driven roller 16b disposed at the front end and the rear end of the surface facing the head unit 11, and rotates. On the upper surface side of the conveyor belt 17, the ink heads of four colors are arranged side by side along the belt moving direction, and the above-described head unit 11 that forms a color image by overlapping a plurality of images is opposed to the above. ing.

  The printed paper S is further conveyed on the normal route CR by a driving mechanism such as a roller. In the case of single-sided printing in which printing is performed only on one side of the sheet S, the sheet S is directly discharged to the sheet discharge port 18 through the sheet discharge route DR, and discharged from the sheet discharge port 18. It is loaded on the table 20 with the printing surface down.

  On the other hand, in the case of double-sided printing in which printing is performed on both sides of the paper S, it is not guided to the paper discharge path DR when printing is completed, but is further conveyed through the housing and sent to the reverse path SR. A switching mechanism 22 for switching the transport path for back side printing is provided at a branch point between the paper discharge path DR and the reversal path SR, and the paper S that has not been sent to the discharge path by the switching mechanism 22 It is drawn into the reverse path SR.

  In the reversing path SR, a sheet is delivered from the normal path CR, and a so-called switchback is performed in which the sheet is reversed by reciprocating the sheet. Then, it is returned to the normal path CR via the switching mechanism 24 by a driving mechanism such as a roller, and is fed again through the registration portion R, and the back side is printed by the same procedure as the front side.

  In addition, the printing apparatus 10 includes an arithmetic processing unit 26. The arithmetic processing unit 26 is configured by a processor such as a CPU or DSP (Digital Signal Processor), memory, hardware such as other electronic circuits, software such as a program having the function, or a combination thereof. Various functional modules are virtually constructed by appropriately reading and executing a program, and various functional modules for processing related to image data, operation control of each unit, and user operations are constructed by each constructed functional module. Process. In addition, an operation panel 28 is connected to the arithmetic processing unit 26, and an instruction and a setting operation by a user can be received through the operation panel 28.

(Paper feeder)
In the present embodiment, a sheet feeding device according to the present invention is provided in the side sheet feeding tray 12 of the sheet feeding system conveyance path FR. FIG. 2 is a front view showing the configuration of the sheet feeding device of the present embodiment. FIG. 3 is a front view showing supply of recording paper to the paper feeding device of the present embodiment. FIG. 4 is a front view showing that the last stacked recording sheet is fed by the sheet feeding device of the present embodiment. FIG. 5 is a perspective view for explaining a sheet feeding table of the sheet feeding device according to the embodiment. 6A and 6B show the sheet stacking amount detecting means of the sheet feeding device according to the present embodiment. FIG. 6A shows a state where the pins do not protrude from the stacking surface of the sheet feeding table, and FIG. It is front sectional drawing which shows the state which protrudes from.

  The paper feeding device 30 according to the present embodiment is a device that feeds paper from the uppermost paper among the papers stacked on the stacking surface of the side paper feeding tray 12 with a conveyance roller. The paper feeding device 30 is a mechanism that sends out the paper S stacked in the side paper feeding tray 12 to the paper feeding system conveyance path FR.

  Specifically, the paper feed device 30 includes a side paper feed tray 12, a side paper feed drive unit 34, and a drive motor (not shown). The side paper feed tray 12 is a box that stores a large number of sheets S in a stacked state. The side paper feed tray 12 includes a paper feed table 36 and a driving force transmission unit (not shown). Is provided.

  The side paper feed drive unit 34 is a drive unit that is located above the side paper feed tray 12 and sends out the paper S stacked on the side paper feed tray 12 to the registration unit R. The side paper feed drive unit 34 includes a downstream pickup roller 44a and an upstream pickup roller 44b, and both the pickup rollers 44a and 44b are rotatably supported by being supported by a rotation shaft. These pickup rollers 44a and 44b pick up and take in the uppermost sheet S of the stacked sheets S one by one and send it to the image forming unit via the registration unit R.

  The drive motor (not shown) is a self-propelled drive mechanism that is attached to the paper feed tray 36 and moves up and down together with the paper feed tray 36 by its driving force. Raise to a possible paper feed position. The drive motor transmits drive force to the side paper feed tray 12 via a drive force transmission unit (not shown), moves up and down together with the paper feed tray 36, and moves up and down the sheets S stacked on the paper feed tray 36. .

  The paper feed table 36 is disposed in the side paper feed tray 12 and is a bottom plate member that has a stacking surface 36u and on which the paper S is stacked. In the present embodiment, a triangular shape is formed in front of both sides of the paper feed path. The sheet S stacked by the both side walls is regulated.

  In addition, the above-described driving force transmission unit is provided on the outer side surfaces of the both side walls of the sheet feeding table 36, and the driving force of the driving motor is transmitted to the sheet feeding table 36 through the driving force transmission unit. The driving force transmission unit is a rack and pinion member that converts the rotational force of the driving motor into the vertical movement of the paper feed table 36.

(Explanation of main parts of paper feeder)
Hereinafter, the main part regarding the invention of the sheet feeding device 30 will be described. The paper feeding device 30 has, on the stacking surface 36u of the paper feed tray 36 on which the paper is stacked, a protruding position U that contacts and rotates the lowermost paper and a retracted position L that does not contact the lowermost paper. And a plurality of rollers 52 (protruding members) whose positions can be switched. The sheet feeding device 30 includes roller position switching means 54 that switches the position of the roller 52 between the protruding position U and the retracted position L.

  The roller position switching means 54 includes a switching mechanism 56 that supports the plurality of rollers 52 so as to be driven to rotate around the rotation axis C and simultaneously switches the height positions of the rollers 52. In the present embodiment, the switching mechanism 56 includes a lever 58 disposed on the side of the paper feed tray 36, and the height position of each roller 52 is switched by switching the rotation position of the lever 58. ing. That is, as shown in FIG. 2, when the lever 58 is oriented horizontally (when placed sideways), each roller 52 is accommodated in the sheet feed table 36, and the roller surface 52 f of each roller 52. Is located at the retracted position L below the sheet stacking surface 36u. As shown in FIG. 3, when the lever 58 is directed in the vertical direction (when it is set up vertically), the roller surface 52f of each roller 52 is positioned above the paper stacking surface 36u, and the paper is fed. The protruding position U is in contact with the sheets stacked on the table 36. Note that an electric switch may be provided instead of the lever 58.

  Further, the sheet feeding device 30 determines a stacking amount of sheets stacked on the stacking surface 36u, and a lever driving unit (not shown) that applies turning force to the lever 58 to switch the height position of each roller 52. And a paper stacking amount detecting means 60 (see FIGS. 5 and 6) for detecting. When the paper load detected by the paper load detection means 60 is larger than the predetermined load, the roller 52 is retracted to the retracted position L, and when it is less than the predetermined load, the roller 52 is protruded to the protruding position U. As described above, the arithmetic processing unit 26 controls the roller position switching means 54.

  In the present embodiment, the paper stacking amount detection means 60 fixes the pin 62 that can project from the opening 64 formed on the stacking surface 36u side of the paper feed tray 36 onto the stacking surface 36u, and the lower end of the pin 62. A pin support member 66 that supports the pin 62 and a compression coil spring 68 that biases the pin support member 66 upward are provided. In the present embodiment, a plurality of openings 64 are formed, a plurality of pins 62 are arranged so as to protrude from each opening 64, and a pin support member 66 and a compression coil spring 68 are provided corresponding to each pin 62. .

  Further, in the present embodiment, it is set when the predetermined stacking amount is one sheet. When two or more sheets are on the sheet feeding table 36, the pin 62 does not protrude above the stacking surface 36u. Each compression coil spring takes into account the weight of the pin 62, the pin support member 66, and the paper S so that the predetermined pin 62 protrudes above the stacking surface 36u when the number of sheets on the paper feed tray 36 becomes one. 68 biasing forces are set (controlled).

As the formation positions of the openings 64, for example, four openings 64 a to 64 d are formed along the center line in the width direction of the paper feed table 36, and the distances d ₁ to d from the end of the paper feed of the paper feed table 36. d ₄ is 130mm, 200mm, 290mm, is 400mm.

(Function, effect)
Hereinafter, the operation and effect of the present embodiment will be described. In the present embodiment, in order to feed paper to the paper feed tray 36, the paper feed tray 36 is moved to the lowest position, and the lever 58 is in a standing state, that is, each roller 52 is positioned at the protruding position U. To a state to do. In that case, raising the lever 58 may be manual or automatic. Since each roller 52 is located at the protruding position U, it is not the stacking surface 36u of the sheet feed table 36 but each roller 52 that supports the sheet bundle B from below.

  Then, the operator stacks the sheet bundle B on the paper feed tray 36 (see FIG. 3) and pushes the sheet bundle B toward the back of the apparatus, whereby each roller 52 is driven to rotate and the sheet bundle B is moved toward the back of the apparatus. Move to. In this way, the sheet bundle B is set in the sheet feeding device 30, and after confirming that the sheet bundle B is set at the sheet feeding position, the roller 52 is moved to the side position by tilting the lever 58 to the retracted position L. Move. As a result, the lower end surface of the sheet bundle B is supported by the stacking surface 36u of the sheet feed table 36 over the entire surface. The lever 58 may be tilted manually or automatically.

  Thereafter, the printing apparatus 10 is operated. The pin 62 does not protrude until the remaining sheet on the sheet feed tray 36 is one sheet. When there is one sheet remaining on the paper feed tray 36, the arithmetic processing unit 26 detects that the predetermined pin 62 is projected by the biasing force of the compression coil spring 68 and the remaining sheet is one sheet, and the roller 52 is turned on. The arithmetic processing unit 62 controls the roller position switching means 54 so as to move it to the protruding position U. As a result, the paper S floats from the stacking surface 36u of the paper feed tray 36, and the frictional force that the paper S receives from the stacking surface 36u of the paper feed tray 36 when the paper S is sent out is reduced. However, it can feed stably.

In the case as described above opened 64a~d as an opening 64 is formed in a position where the distance d ₁ to d _4, respectively, when the sheet on the paper feed table 36 has become one, the paper is A3 paper In the case of (the paper length along the transport direction is 420 mm), the pin 62d protrudes from the opening 64d, and this paper is B4 paper (the paper length along the transport direction is 364 mm) or A4 paper (the paper length along the transport direction). When the paper length is 297 mm, the pin 62c protrudes from the opening 64c, and this paper is B5 paper (paper length along the transport direction is 257 mm) or A4, A4R paper (paper length along the transport direction is In the case of 210 mm), the pin 62b protrudes from the opening 64b, and this paper is B5R paper (paper length along the transport direction is 182 mm) or A5R paper (paper length along the transport direction is 1). In the case of 8 mm), as the pin 62a protrudes from the opening 64a, to set the length and spring constant of the compression coil spring 68.

  According to the present embodiment, it is avoided that the frictional force between the paper and the stacking surface 36u of the paper feed tray 36 increases excessively even for the last sheet on the stacking surface 36u of the paper feed tray 36. It is possible to avoid the occurrence of defective sheet feeding from the paper table 36 and the occurrence of idle feeding. Therefore, in the sheet feeding device 30, when two or more sheets S are stacked on the stacking surface 36u, the lower end surface of the stacked sheet is supported by the stacking surface 36u of the sheet feed table 36 over the entire surface. It is possible to prevent deformation such as undulations and wrinkles, and when only the bottom sheet (last one sheet) remains on the stacking surface 36u, the roller 52 moves to the protruding position U, and this sheet S Can be fed stably.

  Further, when replenishing the sheet bundle B to the sheet feeding device 30, the user moves the roller 52 to the protruding position U, places the sheet bundle B on the roller 52, and pushes the sheet bundle B toward the back of the apparatus. As a result, each roller 52 is driven to rotate, and the sheet bundle B moves to a predetermined supply position (paper feed position) in the rear direction of the apparatus. Accordingly, since the user does not need to carry the sheet bundle B with his bare hands in the depth direction of the apparatus, the burden of replenishing the heavy sheet bundle B is remarkably reduced for the user, and the workability is good and the time is short. It can be carried out.

  In the present embodiment, the pin 62 does not protrude until the remaining sheet on the sheet feed tray 36 becomes one sheet, and the predetermined pin 62 protrudes when the remaining sheet is reached. When the number of sheets on the paper table 36 reaches a predetermined stacking capacity instead of a single sheet, the arithmetic processing unit 26 causes the roller position switching means to project the predetermined pin 62 and move the roller 52 to the projecting position U. 54 may be controlled. In this case, the predetermined stacking amount is a stacking amount (number of sheets) that can prevent the sheet from being deformed, such as wrinkles or undulations, even when the time stored in the side paper feed tray 12 is relatively long. .

  The sheet feeding device 30 further includes a rotating body driving unit 70 (see FIG. 4) for rotating the roller 52 so that the roller 52 is rotated when the sheet on the sheet feeding table 36 becomes the last sheet. Alternatively, the arithmetic processing unit 26 may control the rotating body driving unit 70. As a result, when the paper on the paper feed tray 36 becomes the last one, this one sheet can be sent out more smoothly during printing, and the last one of the paper stacked on the paper feed tray 36 is stable. Thus, it is possible to reliably feed the paper.

  Further, in the present embodiment, the example in which the roller 52 is switched to the protruding position U and the retracted position L has been described. However, other than the roller can be used as long as there is no problem in feeding the paper.

  In the present embodiment, the roller 52 that can rotate around the rotation axis C (see FIG. 3) has been described as being disposed in the paper feeding device 30, but a ball-shaped rotating body is disposed instead of the roller 52. It is also possible to do. Thus, the sheet can be moved in a direction other than the feeding direction by the rotation of the rotating body.

[Second Embodiment]
Next, a second embodiment will be described. This embodiment is different from the first embodiment in the mechanism for switching the position of the roller. FIG. 7 is a perspective view for explaining roller position switching means for switching the roller between a protruding position and a retracted position in the sheet feeding device of the present embodiment. FIG. 8 is a front view for explaining roller position switching means for switching the roller between a protruding position and a retracted position in the sheet feeding device of the present embodiment. In FIG. 8, for the sake of simplification, the roller is described in a single row (one row) instead of a plurality of rows (three rows).

  The sheet feeding device according to the present embodiment has a protruding position U (see FIGS. 3 and 4) that contacts and rotates the lowermost sheet on the stacked surface 36u on which the sheet is stacked, and the lowermost sheet. A roller 82 (protruding member) is provided so as to be switchable to a retracted position L (see FIG. 2) that does not come into contact with.

  The sheet feeding device of this embodiment includes roller position switching means 84 that switches the position of the roller 82 between the protruding position U and the retracted position L. The roller position switching means 84 rotatably supports a plurality of rollers 82 and is supported by a roller support / position switching member 88 and a roller support / position switching member 88 that are rotatably held around a rotation shaft 86. And a power generation unit 90 that provides power.

  The roller support / position switching member 88 includes a plurality of roller holding portions 92 that rotatably hold the rollers 82 at their distal ends, and a rotation shaft 86 that passes through the base end portion 92e of each roller holding portion 92. . The base end portion 92e is fixed to the rotation shaft 86, and the roller holding portion 92 is also rotated with the rotation of the rotation shaft 86.

  Further, the roller support / position switching member 88 includes a rotating power transmission member 94 fixed to one end portion 86 e of the rotation shaft 86. The other end of the rotation shaft 86 is rotatably held by a housing of the paper feed table. In the present embodiment, the rotational power transmission member 94 has a flat plate shape, the piston 91 of the power generation unit 90 is engaged with the lower side of the one end portion 86e of the rotating shaft 86, and the tension coil spring 96 is hooked on the lower side. It has been.

  With this configuration, when the piston 91 is pulled back by the power generation unit 90, the rotation shaft 86 is centered on the one end portion 86e of the rotation shaft 86 via the rotational power transmission member 94 (see FIGS. 7 and 7). 8), and the roller 82 protruding upward from the opening 64 of the stacking surface 36u moves to the retracted position L below the opening 64 of the stacking surface 36u. Further, the piston 91 is always urged in the pushing direction, and the rotation shaft 86 is moved by the tension coil spring 96 via the rotational power transmission member 94 by releasing the pulling force of the power generation unit 90 to the piston 91. The roller 82 rotating in the Q direction and moving to the retracted position L moves to the protruding position U protruding upward from the opening 64.

  According to the present embodiment, it is possible to further easily switch between the protruding position U and the retracted position L of the roller 82 with a simple configuration.

  The power generation unit 90 may apply not only a pullback force but also an extrusion force to the piston 91. Thereby, it can be set as the structure which made the tension coil spring 96 unnecessary.

26 Arithmetic processing part (control means)
30 Paper feeder 36u Loading surface 44a, b Pickup roller (conveyance roller)
52 Roller (protruding member, rotating body)
54 Roller position switching means (protruding member position switching means)
60 Paper load detection means 70 Rotating body drive unit 82 Roller (protruding member)
84 Roller position switching means (protruding member position switching means)
L Retraction position S Paper U Projection position

Claims (2)

In a paper feeding device that feeds paper from the top of the paper stacked on the stacking surface with a transport roller,
A projecting member provided on the stacking surface on which the sheets are stacked so as to be switchable between a projecting position that contacts and rotates the bottom sheet and a retracted position that does not contact the bottom sheet;
Projecting member position switching means for switching the position of the projecting member between the projecting position and the retracted position;
A paper loading amount detecting means for detecting a loading amount of the paper loaded on the loading surface;
The protruding member is retracted to the retracted position when the sheet stacking amount detected by the sheet stacking amount detecting unit is larger than a predetermined stacking amount, and the protruding member is protruded to the protruding position when the sheet stacking amount is less than the predetermined stacking amount. Control means for controlling the protruding member position switching means;
A paper feeding device comprising: The protruding member is composed of a rotating body that is rotatable in a paper feeding direction of paper fed by the transport roller,
A rotating body driving unit that rotates the rotating body;
2. The sheet feeding device according to claim 1, wherein the control unit controls the rotating body driving unit to rotate the rotating body when the rotating body is protruded to the protruding position. 3.

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