JP2019182651A - Sheet supply device - Google Patents

Abstract

To feed out a loaded uppermost sheet one by one.SOLUTION: This device comprises: a floating air blow-out port 29b for blowing-out air from the side of a loaded uppermost paper P (sheet); a flow regulating member 35 which extends from the floating air blow-out port 29b to the upper part of an edge part of the loaded uppermost paper P to generate airflow by the air blown out from the floating air blow-out port 29b along an upper surface of the loaded uppermost paper P; a separation air blow-out port 29c for blowing-out the air from the downstream side in a conveyance direction of the paper P to the space between the uppermost paper P floated to the flow regulating member 35 by the generated airflow and a second paper P, and a separation air blow-out port 29a for blowing-out the air from the side orthogonal to the conveyance direction; a shutter 31d for switching between blow-out and stop of the air by the floating air blow-out port; and a control part 9 which functions as air control means for controlling it.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sheet feeding apparatus that feeds the uppermost sheets stacked on a sheet feeding table one by one.

  For example, there is known a paper feeding device that feeds the uppermost paper stacked on a paper feeding table one by one to an image forming apparatus. In this type of paper feeding device, if the next paper is caught by the burrs generated at the edge of the paper and the papers are brought into close contact with each other due to static electricity, a plurality of papers are overlapped to the image forming device and jammed. It will be a cause.

  In Patent Document 1, a front end abutting portion having a front end abutting surface that contacts the front end side in the transport direction of the paper P stored in the paper storage portion, and a direction orthogonal to the transport direction of the paper P stored in the paper storage portion. An ascent prevention member that abuts on the sheet P that is lifted by the air flow from the blowing unit that blows out the air flow for floating the sheet from the side surface and prevents the contact of the sheet P from rising is provided on the sheet P. A technique related to a paper feeding device that is in the conveyance direction and is located on the side of the suction conveyance unit is disclosed.

JP 2012-131614 A

  Here, in order to send the uppermost sheet to the image forming apparatus one by one, it is necessary to appropriately separate the uppermost sheet and the second sheet.

  However, in the technique described in Patent Document 1, since the air flow is blown out only from the side surface orthogonal to the conveyance direction of the paper P, the pressure between the uppermost sheet and the second sheet does not increase. For this reason, it is difficult to separate the second sheet from the uppermost sheet, and it is difficult to feed out only the uppermost sheet one by one.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to reliably separate the second sheet from the uppermost sheet stacked on the sheet feeding table, and to separate the uppermost sheet one by one. An object of the present invention is to provide a sheet feeding apparatus that can feed out.

In order to achieve the above object, the sheet feeding apparatus according to the present invention has the following features:
A sheet supply device that sucks the uppermost sheet stacked on the sheet stacking table by air suction of a suction conveyance unit and supplies the suctioned sheet to a supply target device.
A floating air outlet for blowing out air from the side of the stacked uppermost sheet;
An air flow is generated along the upper surface of the stacked uppermost sheet by extending above the edge of the uppermost sheet stacked from the floating air outlet and air blown from the floating air outlet. A rectifying member to be
Separation air blowing that blows air from the downstream side in the conveyance direction of the sheet and the side perpendicular to the conveyance direction between the uppermost sheet and the second sheet that have floated to the rectifying member by the generated air flow. Exit,
Air control for controlling the air blowing from the floating air outlet to stop while the uppermost sheet floats up to the rectifying member by the generated air flow and is adsorbed by the suction conveying means Means,
It is in having.

  According to the feature of the sheet feeding apparatus according to the present invention, it is possible to reliably separate the second sheet from the stacked uppermost sheet and to feed the uppermost sheet one by one.

1 is an explanatory diagram showing a schematic configuration of a main part of an ink jet recording apparatus equipped with a paper feeding device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram illustrating a schematic configuration of a sheet feeding device according to an embodiment of the present invention that is applied to an external sheet feeding tray. FIG. 5 is a perspective view illustrating a guide member provided in a width direction of a sheet provided in the sheet feeding device according to the embodiment of the present invention. It is the top view which showed the paper feeder concerning one Embodiment of this invention. It is sectional drawing of the guide member provided in the conveyance direction of the paper P with which the paper feeder which concerns on one Embodiment of this invention is provided. It is explanatory drawing explaining operation | movement of the floating of the paper by the paper feeder which concerns on one Embodiment of this invention. FIG. 10 is an explanatory diagram illustrating an operation of separating the uppermost sheet and the second sheet by the sheet feeding device according to the embodiment of the present invention. 6 is a timing chart for explaining the operation of the sheet feeding device according to the embodiment of the present invention. FIG. 10 is a plan view illustrating a modification of the sheet feeding device according to the embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. Throughout the drawings, the same or equivalent parts and components are denoted by the same or equivalent reference numerals. However, it should be noted that the drawings are schematic and different from the actual ones. Moreover, the part from which the relationship and ratio of a mutual dimension differ also in between drawings is contained.

  Further, the embodiment described below exemplifies an apparatus or the like for embodying the technical idea of the present invention, and the technical idea of the present invention is to arrange the components and the like as follows. It is not something specific. The technical idea of the present invention can be variously modified within the scope of the claims.

  FIG. 1 is an explanatory diagram showing a schematic configuration of a main part of an ink jet recording apparatus equipped with a paper feeding device according to an embodiment of the present invention. The ink jet recording apparatus shown in FIG. 1 is an ink jet line color printer.

  In the following description, the direction orthogonal to the paper surface of FIG. 1 is the left-right direction, and the surface direction of the paper surface is the right side. Also, the top and bottom of the paper surface in FIG. 1 is the vertical direction, and the horizontal direction of the paper surface in FIG. The right direction on the paper is the front and the left direction is the rear. Further, the path indicated by the thick line in FIG. 1 is a transport path R along which the paper P, which is a print medium, is transported. In the following description, upstream and downstream mean upstream and downstream in the transport path R, respectively.

  As shown in FIG. 1, the ink jet recording apparatus 1 of the present embodiment includes a paper feeding unit 2, a printing unit 3, a control unit 9, and an operation panel 10.

  The paper feeding unit 2 feeds the paper P (corresponding to a sheet in the claims) to the printing unit 3. The paper feed unit 2 includes an external paper feed tray 11, an external paper feed unit 12, a plurality of internal paper feed trays 13, a plurality of pairs of internal paper feed rollers 14, a plurality of pairs of internal paper feed transport rollers 15, A registration roller 16.

  The external paper feed tray 11 is for loading paper P used for printing. The external paper feed tray 11 is partly exposed outside the casing (not shown) of the inkjet recording apparatus 1.

  The external paper feed unit 12 takes out the paper P one by one from the external paper feed tray 11 and transports it toward the registration rollers 16 along the transport path R. A sheet sensor 17c for detecting the thickness of the sheet P to be conveyed is provided on the exit side of the external sheet feeding unit 12 in the conveyance path R, and the rising of the external sheet feeding table 11 is stopped on the inner wall surface 27. A paper feed stand stop sensor 17a and a paper floating sensor 17b for detecting whether or not the paper P has floated from the external paper feed tray 11 are provided.

  The internal paper feed tray 13 is for loading paper P used for printing. The internal paper feed tray 13 is disposed inside a casing (not shown) of the inkjet recording apparatus 1.

  The internal paper feed roller 14 takes out the paper P one by one from the internal paper feed tray 13 and sends it out to the transport path R. The internal paper feed roller 14 is rotationally driven by a motor (not shown).

  The internal paper feed conveyance roller 15 conveys the paper P taken out from the internal paper feed tray 13 toward the registration roller 16. The internal paper feeding / conveying roller 15 is disposed along a conveyance path R between the internal paper feeding roller 14 and the registration roller 16. The internal paper feed roller 15 is rotationally driven by a motor (not shown).

  The registration roller 16 temporarily stops the paper P transported from the external paper feed unit 12 or the internal paper feed transport roller 15 and then transports the paper P toward the printing unit 3. The registration roller 16 is disposed on the downstream side of the external paper feeding unit 12 and the internal paper feeding / conveying roller 15. The registration roller 16 is rotationally driven by a motor (not shown).

  The printing unit 3 includes a belt platen unit 3a and four inkjet heads 4A to 4D corresponding to the colors CKMY.

  The belt platen unit 3a conveys the sheet P fed from the sheet feeding unit 2 while holding it on the belt. The belt platen portion 3 a is disposed on the downstream side of the registration roller 16.

  Each of the inkjet heads 4A to 4D prints an image by ejecting ink of each color corresponding to the paper P conveyed by the belt platen unit 3a. The inkjet heads 4A to 4D are disposed above the belt platen portion 3a.

  Each of the inkjet heads 4 </ b> A to 4 </ b> D is configured to be movable in the vertical direction by the head gap adjustment unit 6. The head gap adjustment unit 6 moves the inkjet heads 4A to 4D up and down, thereby adjusting the interval (head gap) between the inkjet heads 4A to 4D and the paper P conveyed by the belt platen unit 3a.

  Below the inkjet heads 4A to 4D, cleaning devices 5A to 5D are provided corresponding to the inkjet heads 4A to 4D. Each of the cleaning devices 5A to 5D receives ink discharged by the purge operation of each inkjet head 4A to 4D for cleaning.

  The cleaning devices 5A to 5D wipe the remaining ink discharged from the inkjet heads 4A to 4D from the nozzle surfaces of the inkjet heads 4A to 4D by the purge operation.

  An external print job is input to the control unit 9. An operation panel 10 is connected to the control unit 9. On the operation panel 10, various information relating to printing, for example, specifications of the paper P loaded on the external paper feed tray 11 and the internal paper feed tray 13 of the paper feed unit 2 (paper size, paper type, etc.) And the environment information (temperature, humidity, etc.) of the installation location of the inkjet recording apparatus 1 are input by the user.

  The control unit 9 supplies the paper P of the external paper feed tray 11 and the internal paper feed tray 13 to the printing unit 3 based on the print setting information of the input print job and the information input from the operation panel 10. The image is printed on the paper P.

  Next, a schematic configuration of a paper feeding device according to an embodiment of the present invention applied to the external paper feeding tray 11 will be described with reference to an explanatory diagram of FIG.

  A sheet feeding device 20 (corresponding to a sheet feeding device in the claims) of this embodiment applied to the external sheet feeding table 11 of FIG. 1 is loaded with sheets P as shown in FIG. The sheet feeding table 21 includes a pair of guide members 23 and 23 erected on both the left and right ends of the sheet feeding table 21 and the sheet conveyance direction end. 2 shows a state in which the paper feeding device 20 is viewed from the main body side (printing unit 3 side) of the ink jet recording apparatus 1 of FIG.

  The paper feed table 21 is moved up and down by the lifting unit 25 in accordance with the increase or decrease of the stacked sheets P. Specifically, the control unit 9 functions as an elevation control means, and the position of a floating air outlet 29b, which will be described later, is positioned at the uppermost position loaded on the paper feed table 21 based on the thickness detected by the paper sensor 17c. The paper feed base 21 is moved up and down by the lift unit 25 so as to be lateral to the position of the paper P. That is, the stacking height of the sheets P stacked on the sheet feed table 21 is reduced by the thickness detected by the sheet sensor 17c, so that the control unit 9 supplies the sheet when the stacked sheet thickness exceeds a threshold value. The base 21 is raised. Then, the control unit 9 stops the raising of the sheet feeding table 21 when the sheet feeding table stop sensor 17a used for positioning the sheet is turned on. In order to accurately detect the upper surface position of the paper, the control unit 9 may be provided with a paper thickness sensor output value and a paper thickness table in advance.

  The external paper feeding unit 12 transports the paper P toward the front transport path R along the circumferential direction of the belt 12a that is rotationally driven by a motor (not shown). The belt 12a is provided with a suction hole (not shown) for sucking air. By driving a fan 12b provided on the inner side of the belt 12a, the paper P is removed from the suction hole of the belt 12a. The sucked air is adsorbed on the surface of the belt 12a and conveyed.

  Each guide member 23 abuts on both the left and right ends of the paper P stacked on the paper feed tray 21 and the paper transport direction end (only the guide members 23 on the left and right ends are shown in the figure). The movement of P in the left-right direction and the conveyance direction is restricted. Each guide member 23 is configured to be movable in the left-right direction with respect to the paper feed table 21 according to the size (paper width) of the paper P.

  An air outlet 29 is formed at the upper end of the inner wall surface 27 in contact with the paper P of each guide member 23. As shown in FIG. 3, the air outlets 29 formed in the respective guide members 23 provided in the width direction (left and right direction) of the paper P are constituted by a separation air outlet 29a and a floating air outlet 29b. ing.

  A rectifying member 35 is attached to the upper edge of the air outlet 29 (separation air outlet 29a, floating air outlet 29b). The rectifying member 35 protrudes from the upper edge of the air outlet 29 at a predetermined mounting angle, for example, slightly upward from the horizontal, and above the left and right edges of the paper P stacked on the paper feed table 21. It is extended.

  The floating air outlet 29b blows air from the side of the uppermost stacked paper P so as to float the paper P stacked on the paper feed tray 21. The air blown from the floating air outlet 29b generates an air flow along the upper surface of the uppermost sheet P stacked on the sheet feed table 21. Due to this air flow, the paper P loaded on the paper feed tray 21 floats up to the rectifying member 35.

  The shape of the floating air outlet 29b is, for example, wider in the vertical direction than the shape of the separation air outlet 29a. This is to make it easier to separate the second sheet P from the uppermost sheet P by increasing the distance over which the uppermost sheet P floats up to the rectifying member 35. However, the shape of the floating air outlet 29b is not limited to the above shape as long as it can float the uppermost sheet P to the rectifying member 35.

  The separation air outlet 29a blows air from the side perpendicular to the transport direction of the paper P between the uppermost paper P and the second paper P that have floated up to the rectifying member 35 by the generated air flow.

  For example, the shape of the separation air outlet 29a is narrower in the vertical direction and longer in the front-rear direction (conveying direction) than the shape of the floating air outlet 29b. This is because the air is surely blown out between the uppermost sheet P and the second sheet P that have floated up to the rectifying member 35, and the second sheet is widened by widening the C1 region where the air flow collides as will be described later. This is because a downward pressing force is generated in a wide range of P. However, the shape of the separation air outlet 29a is not limited to the above shape as long as it can blow air between the uppermost sheet P that has floated up to the rectifying member 35 and the second sheet P.

  As shown in FIGS. 3 and 4, the air flow path 31 formed inside the guide member 23 includes a separation air flow path 31 a and a floating air flow path 31 b. The separation air outlet 29a communicates with the separation air channel 31a, and the separation air channel 31a is connected to the separation air blowing mechanism 33a. The floating air outlet 29b communicates with the floating air flow path 31b, and the floating air flow path 31b is connected to the floating air blowing mechanism 33b. As shown in FIGS. 2 to 4, a pair of shutters 31 d are provided on the floating air flow path 31 b at the center of the guide member 23. The shutter 31d performs an opening / closing operation based on a control signal from the control unit 9. Thereby, the blowing or stopping of air from the floating air outlet 29b can be switched.

  As shown in FIGS. 4 and 5, a guide member 23 is also erected in the paper transport direction of the paper feed tray 21, and the upper end of the inner wall surface 27 that contacts the paper P of the guide member 23 is A separation air outlet 29c is provided, and a floating air outlet 29e is provided below the separation air outlet 29c.

  Similarly to the floating air outlet 29b, the floating air outlet 29e blows air from the side of the uppermost paper P stacked so as to float the paper P stacked on the paper feed tray 21. The air blown from the floating air outlet 29e generates an air flow along the upper surface of the uppermost sheet P stacked on the sheet feed table 21. Due to this air flow, the paper P loaded on the paper feed table 21 rises.

  The floating air outlet 29e communicates with the floating air flow path 31e, and the floating air flow path 31e is connected to the floating air blowing mechanism 33e.

  A shutter 31d is provided on the floating air flow path 31e. The shutter 31d performs an opening / closing operation based on a control signal from the control unit 9. Thereby, the blowing or stopping of air from the floating air outlet 29e can be switched. The shutter 31d may be provided in the floating air blowing mechanism 33e and may perform an opening / closing operation based on a control signal from the control unit 9.

  The separation air outlet 29c blows air from the downstream side in the transport direction of the paper P between the uppermost paper P and the second paper P that are lifted by the air flow generated by the air blown from the floating air outlet 29b. .

  An air flow A3 blown between the uppermost sheet P and the second sheet P from the separation air outlet 29a and between the uppermost sheet P and the second sheet P from the separation air outlet 29c. The blown air flow A4 collides with the C1 region. As a result, the pressure in the C1 region is increased and the second sheet P is pressed downward, so that the second sheet P can be reliably separated from the uppermost sheet P.

  Next, the floating operation of the paper P will be described.

  FIG. 6 is an explanatory diagram illustrating an operation in which the paper P is floated by the air flow blown from the floating air outlet 29b in the paper feeding device 20 of the present embodiment.

  As shown in FIG. 6, the floating air channel 31b has an inclined surface 31b1 inclined in the left-right direction. The inclined surface 31b1 is inclined at the same angle as the mounting angle of the rectifying member 35, for example. Thereby, the flow direction of the airflow can be changed more smoothly from the airflow A0 flowing through the floating air flow path 31b to the airflow A1 described later.

  The jet of air blown out from the floating air outlet 29b becomes an air flow A1 that flows along the lower surface of the rectifying member 35 facing the upper surface of the uppermost sheet P1 stacked on the sheet feed table 21 due to the Coanda effect.

  The air flow A1 flowing along the lower surface of the rectifying member 35 is caused by the nature of the jet flow, while the air existing in the gap B1 between the uppermost sheet P of the paper feed table 21 and the rectifying member 35 is entangled, Head to 37. The air flow A1 that has reached the leading end 37 of the rectifying member 35 becomes an air flow A2 that moves away from the stacked paper P due to the diffraction effect generated at the leading end 37 of the rectifying member 35.

  Therefore, the gap B1 between the uppermost sheet P1 stacked on the sheet feed table 21 and the rectifying member 35 extending above the edge of the sheet P1 is in a negative pressure state, and the uppermost sheet P1 The edge is sucked toward the flow regulating member 35 side. Therefore, as shown in the explanatory diagram of FIG. 6, the gap between the uppermost sheet P1 whose edge is sucked toward the rectifying member 35 and the second sheet P2 stacked on the sheet feed table 21. A gap B2 is formed.

  Next, an operation of separating the uppermost sheet P and the second sheet P will be described.

  FIG. 7 is an explanatory diagram illustrating an operation of separating the uppermost sheet P and the second sheet P by the air flow blown from the separation air outlet 29a in the sheet feeding device 20 of the present embodiment.

  As shown in FIG. 7, the separation air flow path 31a has a horizontal surface 31a1.

  Then, the air blown out from the separation air outlet 29a flows through the gap B2 generated between the uppermost sheet P1 sucked toward the rectifying member 35 and the second sheet P2 from the top against the horizontal plane 31a1. An air flow A3 is formed. Although not shown, similarly, air blown out from the separation air outlet 29c flows through the gap B2, and an air flow A4 is formed.

  As described above, the air flow A3 and the air flow A4 collide with each other, so that the pressure in the C1 region is increased, and a pressing force is generated to push the second paper P downward. The second paper P can be reliably separated.

  Next, the operation of the paper feeding device 20 according to one embodiment of the present invention will be described.

  FIG. 8 is a timing chart for explaining the operation of the sheet feeding device 20 according to the embodiment of the present invention.

  As shown in FIG. 8, when a paper feed signal is supplied from the control unit 9 at time t1, a pre-operation is performed. This pre-operation is a preparatory operation before the paper P is fed. During this pre-operation, the control unit 9 functions as an air control means and is supplied with a fully open signal for fully opening the shutter 31d, and the shutter 31d is maintained in a fully open state. Therefore, since air is blown out from the three directions of the floating air outlets 29b and 29e shown in FIG. 4, the uppermost paper P loaded on the paper feed table 21 by the air flow generated by this air blow-out. However, it floats up to the rectifying member 35. Although not shown, air is also blown out from the separation air outlets 29a and 29c.

  At a time point t2 when a predetermined R1 time has elapsed from the time point t1, the control unit 9 supplies a full-close signal to the shutter 31d so that the shutter 31d starts a closing operation at the time point t3. .

  At the time t4 immediately after that, when the next paper feed signal is supplied from the control section 9, the motor for driving the belt 12a to rotate is started. Then, the paper P is adsorbed on the surface of the belt 12a by the air sucked from the suction holes of the belt 12a and is transported on the transport path R toward the printing unit 3 until time t7. The paper sensor 17c detects the thickness of the paper P transported on the transport path R from time t5 immediately after the start of transport to time t8 when the trailing edge of the paper P is removed.

  On the other hand, since the shutter 31d is fully closed at time t5, air blowing from the floating air outlets 29b and 29e stops. Also at this time, since air is blown out from the separation air outlets 29a and 29c, air flows between the uppermost sheet P and the second sheet P. Therefore, the second sheet P is pushed downward by this pressing force and is loaded on the sheet feeding table 21.

  As described above, the control unit 9 functions as an air control unit, and the uppermost sheet P is lifted up to the rectifying member 35 by the generated air flow, and then is lifted by the floating air blowing while being sucked by the external sheet feeding unit 12. The shutter 31d is controlled so as to stop the air blowing from the outlets 29b and 29e.

  Thereby, when transporting the uppermost sheet P, the second sheet P can be reliably separated to prevent double feeding.

  After the uppermost sheet P is conveyed, preparations for conveying the second sheet P as the next uppermost sheet P are made. At the time t6, which is a predetermined time R2 before the time t7 when the transport of the uppermost sheet P is finished, the control unit 9 supplies a fully open signal for causing the shutter 31d to be fully opened. By this fully open signal, the shutter 31d starts to open at time t7. As a result, air is blown out from the floating air outlets 29 b and 29 e, and the next uppermost sheet P loaded on the sheet feeding table 21 is lifted up to the rectifying member 35 by the air flow generated by the blowing of the air. . Although not shown, air is blown out from the separation air outlets 29a and 29c.

  Then, at time t9 when a predetermined R1 time has elapsed from time t4, the control unit 9 supplies a fully-closed signal to the shutter 31d so that the shutter 31d starts to close at time t10. ing.

  Immediately after that, when the next paper feed signal is supplied from the control unit 9 at time t11, the motor for rotationally driving the belt 12a is started. Then, the paper P is adsorbed to the surface of the belt 12a by the air sucked from the suction holes of the belt 12a and is conveyed.

  By repeatedly executing this operation, the second sheet P can be reliably separated from the uppermost sheet P and the sheet P can be conveyed appropriately.

  As described above, according to the sheet feeding device 20 according to the embodiment of the present invention, the floating air outlets 29b and 29e that blow air from the side of the stacked uppermost sheet P (sheet), and the floating air An air flow is generated along the upper surface of the uppermost sheet P loaded from the air outlet 29b, extending above the edge of the uppermost sheet P stacked from the air outlet 29b, and being blown out from the floating air outlet 29b. A separation air outlet 29c that blows air from the downstream side in the transport direction of the paper P between the straightening member 35 and the uppermost paper P that has floated up to the straightening member 35 by the generated air flow; A separation air outlet 29a that blows out air from the side perpendicular to the transport direction. The control unit 9 functions as an air control unit, and the uppermost sheet P floats up to the rectifying member 35 by the generated air flow. After, outside While it is adsorbed by the sheet feed unit 12, the floating air outlet 29 b, and stops the balloon of air from 29e.

  More specifically, after the uppermost sheet P floats up to the rectifying member 35 due to the generated air flow, the control unit 9 detects the air from the floating air outlets 29b and 29e while being adsorbed by the external sheet feeding unit 12. The opening / closing operation of the shutter 31d is controlled so as to stop the air blowing.

  Therefore, the air flow generated by the air blown from the separation air outlet 29a and the air flow generated by the air blown from the separation air outlet 29c collide with each other in the C1 region. As a result, the pressure in the C1 region is increased and the second sheet P is pressed downward, so that the second sheet P is reliably separated from the uppermost sheet P and the uppermost sheet is sent out one by one. be able to.

  Note that the control unit 9 supplies a fully open signal for fully opening the shutter 31d at the time t6 before the predetermined time R2 from the time t7 when the conveyance of the uppermost sheet P is finished. However, the present invention is not limited to this. Absent.

  For example, from the time when the control unit 9 functions as an air control unit and instructs to stop the air blowing from the floating air outlet 29b according to the thickness and size of the paper P, the floating air outlets 29b and 29e are next. It is also possible to determine the time until an instruction to start blowing air from is started. As shown in FIG. 8, from the time point t6, which is the time point when the air blowing from the floating air outlets 29b and 29e is instructed to stop, the next instruction to start the air blowing from the floating air outlets 29b and 29e is t8. The time R3 until the point in time is a time for the uppermost paper P stacked on the paper feed table 21 to float.

  Since the thicker the paper P is, the more time it takes to float the paper P, the schedule may be set so as to increase the time R3. Further, the larger the size of the paper P, the longer it takes to float the paper P. Therefore, the schedule may be set so that the time R3 is lengthened.

  As a result, regardless of the thickness and size of the paper P, it is possible to appropriately float the uppermost paper P stacked on the paper feed table 21.

  Further, the control unit 9 functions as an elevation control means, and the positions of the floating air outlets 29b and 29e are based on the thickness detected by the paper sensor 17c, so that the uppermost paper P loaded on the paper feed table 21 is placed. The paper feed table 21 is moved up and down by the lift unit 25 so as to be lateral to the position. That is, the stacking height of the sheets P stacked on the sheet feed table 21 is lowered by the thickness detected by the sheet sensor 17c, and the sheet feed table 21 is raised accordingly.

  As a result, the position of the uppermost sheet P loaded on the sheet feed tray 21 is located on the side of the positions of the floating air outlets 29b and 29e, and therefore the uppermost sheet P appropriately loaded on the sheet feed tray 21. Can surface.

  In the present embodiment, as shown in FIG. 5, the configuration in which the separation air outlet 29c is provided at the upper end of the inner wall surface 27 and the floating air outlet 29e is provided therebelow is described. Not limited to.

  As shown in FIG. 9, floating air outlets 29e may be provided on the left and right of the separation air outlet 29c. Also in this case, each floating air outlet 29e communicates with the floating air flow path 31e, and the floating air flow path 31e is connected to the floating air blowing mechanism 33e. A shutter 31d is provided on the floating air flow path 31e, and the shutter 31d performs an opening / closing operation based on a control signal from the control unit 9.

  Each guide member 23 is configured to be movable in the left-right direction with respect to the paper feed table 21 in accordance with the size (paper width) of the paper P, but is further configured to be movable in the front-rear direction. It may be. Thus, the floating air outlet 29b is located at a predetermined position in the length of the paper P in the transport direction (for example, closer to the transport direction than the center of the length of the paper P in the transport direction) so that the paper P is more appropriately floated. Since each guide member 23 can be moved in the front-rear direction so as to be positioned, the paper P can be floated more appropriately.

  In the present embodiment, the case where the paper feeding device 20 is a part of the ink jet recording apparatus 1 (external paper feeding stand 11) has been described. It can also be applied to an attached paper feeding device.

  In the present embodiment, the case where the present invention is applied to the external paper feed tray 11 of the inkjet recording apparatus 1 to configure the paper feed device 20 that supplies the paper P to the printing unit 3 has been described. The present invention can be widely applied to an apparatus that supplies thin sheets other than paper one by one to a supply target.

(Appendix)
The present application discloses the following inventions.

(Appendix 1)
A sheet supply device that sucks the uppermost sheet stacked on the sheet stacking table by air suction of a suction conveyance unit and supplies the suctioned sheet to a supply target device.
A floating air outlet for blowing out air from the side of the stacked uppermost sheet;
An air flow is generated along the upper surface of the stacked uppermost sheet by extending above the edge of the uppermost sheet stacked from the floating air outlet and air blown from the floating air outlet. A rectifying member to be
A separation air outlet for blowing air from the downstream side and the side of the sheet in the conveying direction between the uppermost sheet and the second sheet that have floated up to the rectifying member by the generated air flow;
Air control means for stopping the blowing of air from the floating air outlet while the uppermost sheet floats up to the rectifying member by the generated air flow and is adsorbed by the suction conveyance means;
A sheet feeding apparatus comprising:

(Appendix 2)
Comprising switching means for switching between blowing out or stopping the air from the floating air outlet,
The sheet supply apparatus according to (Appendix 1), wherein the air control unit controls the switching unit.

(Appendix 3)
The air control means includes
In accordance with the thickness and size of the sheet, a time period from the time when the air blowing from the floating air outlet is instructed to stop until the next time when the air blowing is instructed is determined (Appendix 1). ) Or (Supplementary Note 2).

(Appendix 4)
An elevating mechanism for elevating and lowering the sheet stacking table;
Detecting means for detecting the thickness of the sheet being conveyed to the supply target device by the suction conveying means;
Based on the thickness detected by the detection means, the lifting / lowering mechanism lifts and lowers the sheet stacking table so that the floating air outlet is arranged on the side of the uppermost sheet stacked on the sheet stacking table. Elevating and lowering control means,
The sheet supply apparatus according to any one of (Appendix 1) to (Appendix 3), further comprising:

DESCRIPTION OF SYMBOLS 1 Inkjet recording device 2 Paper feed part 3 Printing part (apparatus to supply)
3a Belt platen units 4A to 4D Inkjet heads 5A to 5D Cleaning device 6 Head gap adjustment unit 9 Control unit 10 Operation panel 11 External sheet feed table (sheet stacking table)
12 External paper feeding unit 12a Belt 12b Fan 13 Internal paper feed stand 14 Internal paper feed roller 15 Internal paper feed transport roller 16 Registration roller 17a Paper feed stand stop sensor 17b Paper floating sensor 17c Paper sensor 20 Paper feed device 21 Paper feed stand 23 Guide member 25 Elevating unit (elevating mechanism)
27 inner wall surface 29 air outlet 29a, 29c separation air outlet 29b floating air outlet 31 air flow path 31a separation air flow path 31b floating air flow path 31d shutter (switching means)
33a, 33c Separation air blowing mechanism 33b Floating air blowing mechanism 35 Rectification member

Claims (4)

A sheet supply device that sucks the uppermost sheet stacked on the sheet stacking table by air suction of a suction conveyance unit and supplies the suctioned sheet to a supply target device.
A floating air outlet for blowing out air from the side of the stacked uppermost sheet;
An air flow is generated along the upper surface of the stacked uppermost sheet by extending above the edge of the uppermost sheet stacked from the floating air outlet and air blown from the floating air outlet. A rectifying member to be
A separation air outlet for blowing air from the downstream side and the side of the sheet in the conveying direction between the uppermost sheet and the second sheet that have floated up to the rectifying member by the generated air flow;
Air control means for stopping the blowing of air from the floating air outlet while the uppermost sheet floats up to the rectifying member by the generated air flow and is adsorbed by the suction conveyance means;
A sheet feeding apparatus comprising: Comprising switching means for switching between blowing out or stopping the air from the floating air outlet,
The sheet supply apparatus according to claim 1, wherein the air control unit controls the switching unit. The air control means includes
The time from when the stop of blowing out air from the floating air outlet is instructed until the next start of blowing out air is determined according to the thickness and size of the sheet. Or the sheet supply apparatus of 2. An elevating mechanism for elevating and lowering the sheet stacking table;
Detecting means for detecting the thickness of the sheet being conveyed to the supply target device by the suction conveying means;
Based on the thickness detected by the detection means, the lifting / lowering mechanism lifts and lowers the sheet stacking table so that the floating air outlet is arranged on the side of the uppermost sheet stacked on the sheet stacking table. Elevating and lowering control means,
The sheet feeding apparatus according to claim 1, further comprising:

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