JP2013091550A - Sheet feeding device and image forming apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeding device where each sheet is properly dispersed and thus double feed of the sheets is hardly caused because the deviation of the distribution of an air inflow amount is small on the sheet surface of a sheet bundle.SOLUTION: Respective blowout ports 77a, 78a are displaced from each other in a direction (in a direction parallel to a drawing direction E) parallel to both side end surfaces wa of the sheet bundle W, so each air Ka, kb which is blown out of the respective blowout ports 77a, 78a are blown onto respective different positions on the both side end surfaces wa of the sheet bundle W. Accordingly, the air enters entire gap of respective recording sheets Pa1, Pa2 of the sheet bundle W, so the respective recording sheets Pa1, Pa2 are properly separated.

Description

  The present invention relates to a sheet feeding device that draws out and feeds a sheet from a bundle of sheets stacked on a sheet stacking table, and an image forming apparatus including the sheet feeding device.

  This type of paper feeding device includes a paper stacking table on which a stack of sheets is stacked, a paper transporting belt disposed above the paper stacking base, and a fan that sucks air through the vent holes of the paper transporting belt. In some cases, the uppermost sheet of the sheet bundle is attracted to and conveyed by the sheet conveying belt by suction of air through the ventilation holes of the conveying belt.

  Also, in such a paper feeding device, air is blown onto the end face of the sheet bundle, air is allowed to enter between the sheets of the sheet bundle, the sheets are dispersed, and the sheets are sucked one by one from the sheet bundle. Making it easy to pull out.

  For example, in Patent Document 1, air is blown from a fan to a bellows duct, and the air is blown through the bellows duct to the side end surface of the sheet bundle to vary the sheets of the sheet bundle.

  Further, in Patent Document 2, air is blown from the three fans to both side end surfaces and the rear end surface of the sheet bundle to vary the sheets of the sheet bundle.

  Further, in Patent Document 3, air is blown from both fans to both end faces of the sheet bundle, and the sheets of the sheet bundle are dispersed. In addition, the amount of air blown by each fan can be adjusted.

  Further, in Patent Document 4, each air blown from two fans is blown in an oblique direction from the both end faces to the rear end face of the sheet bundle, thereby causing the sheets of the sheet bundle to vary.

  Further, in Patent Document 5, air is blown from the fan to the side end surface of the sheet bundle through the fins to vary the sheets of the sheet bundle. Further, the air flow is disturbed by the fins, and the air is allowed to enter between the sheets of the sheet bundle from multiple directions.

JP-A-2005-335585 JP 2008-87906 A JP 2010-202372 A JP-A-7-277541 JP 2008-30903 A

  However, in Patent Documents 1 and 5, since air is blown only on one end face of the sheet bundle, it is difficult for air to enter the entire sheet surface of the sheet bundle. In any of Patent Documents 2 to 4, air is blown to the same position on both side end faces of the sheet bundle (the same position in the direction parallel to the both end faces of the sheet bundle). The distribution of air intrusion amount is biased. For this reason, even if each sheet has a good dispersion at a part where the air intrusion amount is large on the sheet surface of the sheet bundle, each sheet does not vary at a part where the air entry amount is small, which causes a double feed of the sheets. It was.

  Therefore, the present invention has been made in view of the above-described conventional problems, and the deviation of the distribution of the air intrusion amount on the sheet surface of the sheet bundle is small, each sheet is well dispersed, and sheet multi-feeding hardly occurs. It is an object of the present invention to provide a sheet feeding device and an image forming apparatus including the sheet feeding device.

  In order to solve the above-described problems, a paper feeding device according to the present invention is configured to suck a sheet stacking table on which a stack of sheets are stacked and air through a vent hole of the sheet transport member, and to transfer the sheets of the sheet bundle to the sheet transport member. A plurality of air blowing units for sucking and blowing air to both end faces of the sheet bundle, the sheet feeding unit including a sheet conveying unit that sucks and conveys the sheet to the sheet conveying path by the sheet conveying member The air blowing positions of the both side end faces of the sheet bundle to which air is blown by the air blowing portions are shifted from each other in the direction parallel to the both end faces of the sheet bundle.

  In the present invention, the air blowing position with respect to one side end face of the sheet bundle and the air blowing position with respect to the other side end face of the sheet bundle are shifted from each other in a direction parallel to the both end faces of the sheet bundle. Air enters different parts of the sheet surface of the sheet bundle, and the deviation of the distribution of the air intrusion amount on the sheet surface is reduced.

  Further, in the paper feeding device of the present invention, each of the air blowing portions includes a blowout port for blowing air to both side end surfaces of the sheet bundle, and the position of each of the blowout ports is defined as both side end surfaces of the sheet bundle. They are offset from each other in parallel directions.

  In this way, the positions of the outlets are shifted from each other in the direction parallel to the both end faces of the sheet bundle, so that the respective air blowing positions with respect to the both end faces of the sheet bundle are shifted from each other in the direction parallel to the both end faces of the sheet bundle. Can do.

  Further, the paper feeding device of the present invention includes a displacement portion that displaces the position of each outlet in a direction parallel to the both end surfaces of the paper bundle. Further, the displacement unit displaces the position of each outlet in the same direction parallel to both end surfaces of the sheet bundle. Alternatively, the displacement unit displaces the positions of the respective outlets in directions opposite to each other in parallel to the both end surfaces of the sheet bundle.

  Thus, if the position of each outlet is displaced in a direction parallel to the both end surfaces of the sheet bundle, air can enter into a wider area of the sheet surface of the sheet bundle, and each sheet is more likely to vary. Double feed is less likely to occur.

  Further, in the paper feeding device of the present invention, the abutment that moves in a direction parallel to both end surfaces of the sheet bundle on the sheet stacking table, abuts against a rear end surface of the sheet bundle, and positions the sheet bundle. And the displacement portion moves the position of each outlet in a direction parallel to both side end surfaces of the sheet bundle in conjunction with movement of the contact portion in a direction parallel to both side end surfaces of the sheet bundle. It is displaced.

  Since the abutting portion comes into contact with the rear end surface of the sheet bundle, it is positioned at a position corresponding to the sheet size of the sheet bundle. Therefore, when the position of each outlet is linked to the movement of the contact portion, the position of each outlet can be accurately set according to the size of the sheet in the sheet bundle.

  Further, in the paper feeding device of the present invention, each air blowing section includes a blowout port for blowing air to both side end surfaces of the sheet bundle, and the air blowing direction from each blowout port is set to each air. Directed to the spray position.

  Thus, the air blowing direction from each outlet may be directed to each air blowing position.

  In the paper feeding device of the present invention, a displacement unit is provided for displacing the blowing direction of the air from each of the blowing ports.

  When the air blowing direction from each outlet is displaced in this way, air enters a wider area of the sheet surface of the sheet bundle, and each sheet is more likely to vary, making it difficult for multiple sheets to be fed.

  On the other hand, an image forming apparatus of the present invention includes the paper feeding device of the present invention.

  Such an image forming apparatus of the present invention also has the same operational effects as the sheet feeding apparatus of the present invention.

  According to the present invention, the air blowing position with respect to one side end face of the sheet bundle and the air blowing position with respect to the other side end face of the sheet bundle are shifted from each other in a direction parallel to the both end faces of the sheet bundle. Therefore, air enters different parts of the sheet surface of the sheet bundle, and the deviation of the distribution of the air intrusion amount on the sheet surface is reduced, so that each sheet is likely to vary and sheet multi-feeding is unlikely to occur.

1 is a cross-sectional view illustrating an image forming apparatus to which a first embodiment of a paper feeding device of the present invention is applied. 1 is a plan view illustrating a paper feeding device according to a first embodiment. 1 is a front view illustrating a sheet feeding device according to a first embodiment. FIG. 3 is a perspective view illustrating the sheet feeding device according to the first embodiment with the sheet drawer portion removed, as viewed obliquely from the rear. FIG. 3 is a perspective view illustrating a sheet drawer portion of the sheet feeding device according to the first embodiment when viewed obliquely from the upper front. It is a perspective view which shows a paper drawer part seeing from diagonally upper back. It is a perspective view which shows a paper drawer part seeing from diagonally lower back. 1 is a cross-sectional view schematically illustrating a sheet feeding device according to a first embodiment. FIG. 4A is a plan view schematically showing the positional relationship between an air outlet and a sheet bundle in the sheet feeding device of the first embodiment, and FIG. It is a side view which shows the state which carried out. (A) is a plan view schematically showing a positional relationship between an air outlet and a sheet bundle in a conventional apparatus, and (b) shows a state in which air has entered a specific portion of a gap between recording sheets of the sheet bundle. It is a side view. It is a top view which shows roughly the modification of the paper feeder of 1st Embodiment. FIG. 6 is a perspective view showing a sheet feeding device according to a second embodiment in a state in which a sheet drawer is removed, as viewed obliquely from the rear. It is sectional drawing which shows the assist duct in the paper feeder of 2nd Embodiment. It is a perspective view which shows the assist duct of the paper feeder of 2nd Embodiment. FIG. 10 is a plan view schematically showing a positional relationship between a movement of an air outlet and a sheet bundle in a sheet feeding device according to a second embodiment. It is a perspective view which shows the modification of the paper feeder of 2nd Embodiment seeing from diagonally back. FIG. 10 is a plan view schematically showing a positional relationship between a movement of an air outlet and a sheet bundle in a modification of the sheet feeding device. It is a figure which shows roughly the modification of the blowing outlet of air. FIG. 10 is a perspective view illustrating a sheet feeding device according to a third embodiment in a state in which a sheet drawer is removed, as viewed obliquely from the rear. FIG. 10 is a plan view schematically illustrating a positional relationship between a direction of an air outlet and a sheet bundle in a sheet feeding device according to a third embodiment. It is a top view which shows roughly the paper feeder of 4th Embodiment. (A) is a top view which shows roughly the example of the change of the blowing direction of the air in the paper feeder of 4th Embodiment, and the positional relationship of a sheet | seat bundle, (b) is another example of the change of the blowing direction of air. FIG. 6 is a plan view schematically showing a positional relationship of a sheet bundle.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view showing an image forming apparatus to which a first embodiment of a paper feeding device of the present invention is applied. The image forming apparatus 1 is roughly composed of a document reading device 2, a printing unit 11, a paper transport unit 12, a paper supply unit 13, and a large-capacity paper feed cassette (LCC) 14.

  In the printing unit 11, after the residual toner on the surface of the photosensitive drum 21 is removed and collected by the cleaning device 26, the surface of the photosensitive drum 21 is uniformly charged to a predetermined potential by the charging device 22, and then the laser exposure device 23. The surface of the photosensitive drum 21 is exposed to form an electrostatic latent image on the surface, and the developing device 24 develops the electrostatic latent image on the surface of the photosensitive drum 21 to form a toner image on the surface of the photosensitive drum 21. To do.

  The transfer roller 25 is pressed against the photosensitive drum 21 to form a nip area with the photosensitive drum 21, and the recording paper conveyed through the paper conveyance path 33 is sandwiched and conveyed in the nip area. At the same time, the toner image on the surface of the photosensitive drum 21 is transferred onto the recording paper. Then, the recording paper is sandwiched between the heating roller 28 and the pressure roller 29 of the fixing device 27 and heated and pressed to fix the color toner image on the recording paper.

  On the other hand, the paper supply unit 13 includes a plurality of paper supply cassettes 38. Each paper feed cassette 38 includes a pickup roller 39 and the like for pulling out and feeding out recording sheets one by one, and sends out the pulled-out recording sheets to the sheet transport path 33 of the sheet transport section 12.

  The large-capacity paper feed cassette (LCC) 14 can store a large amount of recording paper, pulls out the recording paper one by one, and sends it out to the paper transport path 33 of the paper transport section 12.

  The recording sheet is conveyed through a sheet conveying path 33 and is discharged to a sheet discharge tray 37 via a transfer roller 25 and a fixing device 27 and a sheet discharge roller 36. In this paper conveyance path 33, the recording paper is temporarily stopped and the leading edges of the recording paper are aligned, and then the recording paper is fed in accordance with the transfer timing of the toner image in the nip area between the photosensitive drum 21 and the transfer roller 25. A registration roller 32 for starting conveyance, a conveyance roller 31 for urging conveyance of a recording sheet, a sheet discharge roller 36, and the like are arranged.

  Further, when printing not only on the front side of the recording paper but also on the back side, the position of the branch claw 35 is switched, and the recording paper is conveyed in the reverse direction from the paper discharge roller 36 to the reverse path 34, so that the recording paper The front and back sides are reversed, and the recording paper is again guided to the registration roller 32, and an image is recorded and fixed on the back surface of the recording paper in the same manner as the front surface of the recording paper, and the recording paper is discharged to the paper discharge tray 37.

  Next, the document reading device 2 mounted on the upper body of the image forming apparatus 1 will be described. In the document reading apparatus 2, the document conveying unit 42 is pivotally supported on the inner side of the first reading unit 41 by a hinge (not shown), and the document conveying unit 42 is moved up and down to move the front portion up and down. 42 can be opened and a document sheet can be placed on the platen glass 44 of the first reading unit 41.

  In the first reading unit 41, the first scanning unit 45 illuminates the original paper surface on the platen glass 44 with the light source 51 while moving in the sub-scanning direction, and reflects the reflected light by the first reflecting mirror 52. Guide to the second scanning unit 46. The second scanning unit 46 reflects the reflected light from the original paper by the second and third reflecting mirrors 53 and 54 while moving following the first scanning unit 45. The reflected light is condensed on a CCD 48 (Charge Coupled Device) by the imaging lens 47, and the image of the original paper is read by the CCD 48.

  When reading the image on the surface of the original sheet conveyed by the original conveying section 42, the first scanning unit 45 is moved to a reading position below the original reading glass 55 as shown in FIG. The second scanning unit 46 is positioned according to the position. In this state, the original paper on the original tray 57 is pulled out by the pickup roller 56, the original paper is conveyed through the original conveyance path 58, and the surface of the original paper is passed through the original reading glass 55 by the light source 51 of the first scanning unit 45. Illuminated, the reflected light from the original paper is guided to the imaging lens 47 by the respective reflection mirrors of the first and second scanning units 45 and 46, the image of the original paper is read by the CCD 48, and the original paper is discharged to the original paper discharge roller 61. To the document discharge tray 62.

  A second reading unit 43 (Contact Image Sensor (CIS)) built in the document conveying unit 42 passes under the second reading unit (CIS) 43 and moves to the document discharge tray 62. The back side of the discharged original paper is illuminated, the reflected light from the back side of the original paper is received, and the image on the back side of the original paper is read.

  The original paper image read by the CCD 48 and the CIS 43 in this way is input to the laser exposure device 23 of the image forming apparatus 1, and the image is recorded on the recording paper in the image forming apparatus 1, and this recording paper is output as a copy original. Is done.

  Next, the configuration of the paper feeding device 71 according to the first embodiment built in the large capacity paper feeding cassette 14 will be described in detail. The paper feeding device 71 stacks and stores a large amount of recording paper, pulls out the recording paper one by one, and sends it out to the paper transport path 33 (shown in FIG. 1).

  2 and 3 are a plan view and a front view showing the paper feeding device 71 according to the first embodiment. As shown in FIGS. 2 and 3, the sheet feeding device 71 is disposed on the outer frame 72, the bottom plate 73, the sheet stacking plate 74 disposed on the inner side of the outer frame 72, and one end upper side of the outer frame 72. A paper drawer 75 and the like are provided.

  The sheet stacking table 74 is used for stacking a large amount of recording sheets (sheet bundle) and is provided inside the outer frame 72 so as to be moved up and down. The paper stacking base 74 is formed with an opening 74 a that is long in the recording paper drawing direction (paper transport direction) E. The paper trailing edge guide 76 is supported on the bottom plate 73 so as to be reciprocally movable along the recording paper drawing direction E, and protrudes upward through the opening 74 a of the paper stacking table 74. The recording paper drawing direction (paper conveyance direction) E is the front, and the direction opposite to the drawing direction E is the rear.

  Recesses 74b are formed on both sides of the sheet stacking table 74, and assist ducts 77 and 78 are disposed in the respective recesses 74b. The assist ducts 77 and 78 are supported on both sides of the bottom plate 73 so as to be reciprocally movable in a direction orthogonal to the drawing direction E, and are moved so as to approach each other or interlock with each other so as to be separated from each other. Moved.

  Further, the recesses 74b of the paper stacking table 74 are displaced from each other in a direction parallel to the both end surfaces of the paper bundle (a direction parallel to the drawing direction E), and the assist ducts 77 and 78 are also parallel to the drawing direction E. Are shifted from each other.

  The paper drawing section 75 includes four endless paper conveyance belts 81, a set of rollers 82 and 83 that bridge the paper conveyance belts 81, an intake / exhaust fan 84, an intake duct 85, an exhaust duct 86, and the like. Yes. Each paper transport belt 81 is formed with a large number of air holes 81 a, and air is sucked from the air holes 81 a of each paper transport belt 81 to the intake / exhaust fan 84 through the intake duct 85. Further, the air exhausted from the intake / exhaust fan 84 is guided through the exhaust duct 86 and is blown out from the exhaust duct 86 to the inside of the outer frame body 72 in the direction opposite to the extraction direction E (rearward).

  FIG. 4 is a perspective view showing the outer frame body 72, the bottom plate 73, the paper stacking board 74, and the like as viewed obliquely from the rear side with the paper drawing portion 75 removed. As shown in FIG. 4, the exhaust ports of the assist fans 79 and 80 are connected to the outside of the assist ducts 77 and 78. Each of the assist ducts 77 and 78 is a hollow body and has a ventilation path therein. Air sucked by each of the assist fans 79 and 80 is sent to the ventilation paths of the respective assist ducts 77 and 78. The air is blown out to the inside of the outer frame 72 from the blowout ports 77a and 78a of the assist ducts 77 and 78.

  Further, as described above, the assist ducts 77 and 78 are not only displaced from each other in the direction parallel to the both end surfaces of the sheet bundle (the direction parallel to the drawing direction E), but the assist ducts 77 and 78 are blown out. The ports 77a and 78a are not opposed to each other in the direction parallel to the drawing direction E.

  As shown in FIGS. 2 and 4, the paper trailing edge guide 76 can reciprocate along the recording paper drawing direction E, and is positioned at an arbitrary position in the drawing direction E. Further, as shown in FIGS. 2 and 4, each of the assist ducts 77 and 78 can reciprocate in a direction orthogonal to the drawing direction E, and is positioned at an arbitrary position in the direction orthogonal to the drawing direction E.

  Here, when the sheet bundle is mounted on the sheet stacking board 74, the sheet rear end guide 76 is moved rearward to widen the gap between the sheet rear end guide 76 and the contact plate 72b of the outer frame 72, or The assist ducts 77 and 78 are moved in directions away from each other so that the space between the assist ducts 77 and 78 is wide open. In this state, the sheet bundle is placed on the sheet stacking table 74, and then the sheet trailing edge guide 76 is moved in the drawing direction E, and the trailing edge of the sheet bundle is pushed in the drawing direction E by the column portion 76a of the sheet trailing edge guide 76. Then, the sheet bundle is slid and moved on the sheet stacking table 74, the leading end of the sheet bundle is brought into contact with the contact plate 72 b of the outer frame body 72, and the leading end and the trailing end of the sheet bundle are aligned with the pillars of the sheet trailing end guide 76 Positioning is performed by being sandwiched between the portion 76a and the contact plate 72b of the outer frame 72. Further, the assist ducts 77 and 78 are moved in a direction approaching each other so that both ends of the sheet bundle are sandwiched between the assist ducts 77 and 78 and positioned.

  Further, as shown in FIG. 4, two protruding pieces 74 c are formed on both sides of the paper stacking base 74, and each protruding piece 74 c protrudes from the opening 72 a on both sides of the outer frame 72. On one side of the outer frame 72, two wires 87 are connected to the protruding pieces 74 c on one side of the paper stacking base 74, and each wire 87 is hooked around a plurality of driven pulleys 88 and drawn around a take-up pulley 89. It is connected. On the other side of the outer frame 72, the other two wires 87 are connected to the protruding pieces 74c on the other side of the sheet stacking table 74, and the other wires 87 are connected to a plurality of other driven pulleys 88. It is drawn around and connected to another take-up pulley 89. Each winding pulley 89 is fixed to both ends of a common shaft 91 that is rotatably supported. The shaft 91 is rotationally driven by a pulse motor 92 to rotate each winding pulley 89, and each wire 87 is wound to each winding 87. It is wound around the pulley 89 and is fed out from each winding pulley 89.

  When the shaft 91 is rotationally driven by the pulse motor 92 and each take-up pulley 89 is rotated in the clockwise direction, each wire 87 is taken up by each take-up pulley 89, the paper stacking table 74 is raised, and each take-up pulley 89 is also turned up. When the take-up pulley 89 is rotated in the counterclockwise direction, each wire 87 is fed out from each take-up pulley 89, and the sheet stacking table 74 is lowered. Further, the rotation angle of the take-up pulley 89 that is rotationally driven by the pulse motor 92 and the height of the paper stacking base 74 are in a corresponding relationship. Therefore, by controlling the rotation direction and rotation angle of the pulse motor 92, the height of the sheet stacking base 74 can be adjusted and set.

  Next, the configuration of the paper drawer 75 will be described in detail. FIG. 5 is a perspective view showing the paper drawer portion 75 as viewed obliquely from the upper front. FIG. 6 is a perspective view showing the paper drawer portion 75 as viewed obliquely from above and behind, and FIG. 7 is a perspective view showing the paper drawer portion 75 as seen from diagonally below and rear.

  As shown in FIGS. 5, 6, and 7, the paper drawer 75 includes four endless paper transport belts 81, a set of rollers 82 and 83 that bridge the paper transport belts 81, an intake / exhaust fan 84, An intake duct 85 and an exhaust duct 86 are provided.

  The intake duct 85 is a hollow body, and has an air suction path that is long in a direction orthogonal to the drawing direction (paper conveyance direction) E, and one end 85 a thereof is connected to the intake / exhaust fan 84. Then, as indicated by an arrow F, air is sucked from the air suction path of the intake duct 85 to the intake port (not shown) of the intake / exhaust fan 84 through the one side end 85a.

  The front end portion 85c and the rear end portion 85d of the intake duct 85 are formed with respective recesses 85h. The rollers 82 and 83 are disposed in these recesses 85h and are rotatably supported. The output shaft of the transport motor 93 is connected to the shaft of the front roller 82. Each sheet conveying belt 81 is stretched between the rollers 82 and 83, slightly separated from the upper surface 85 b of the intake duct 85, and is in contact with the lower surface 85 g of the intake duct 85.

  Further, an air suction port 94 (shown in FIG. 8) is provided on the lower surface 85 g of the intake duct 85 for each paper transport belt 81 so as to overlap with the plurality of air holes 81 a of the paper transport belt 81.

  Here, the front roller 82 is rotationally driven in the arrow direction D by the transport motor 93, the rear roller 83 is driven to rotate, and each paper transport belt 81 rotates in the arrow direction D. In addition, air in the intake duct 85 is sucked by the intake / exhaust fan 84, and the air flows into the air suction port 94 (shown in FIG. 8) on the lower surface 85g of the intake duct 85 and the air holes 81a of the paper transport belt 81. The recording paper is attracted to the surface of each paper transport belt 81, and the recording paper is transported by each paper transport belt 81.

  On the other hand, the exhaust duct 86 is also a hollow body and has a long ventilation path in a direction orthogonal to the drawing direction E. One end 86a of the exhaust duct 86 is connected to the intake / exhaust fan 84 and is indicated by an arrow K. As described above, air is sent from the exhaust port (not shown) of the intake / exhaust fan 84 to the ventilation path of the exhaust duct 86 through the one end 86a of the exhaust duct 86.

  In addition, each exhaust port 86 b communicating with the ventilation path of the exhaust duct 86 is formed in the inner wall 86 d of the exhaust duct 86. An inner wall 86d of the exhaust duct 86 is provided so as to overlap with an outer surface of a contact plate 72b (shown in FIG. 4) of the outer frame 72, and each exhaust port 86b of the exhaust duct 86 is a contact plate of the outer frame 72. It faces the inside of the outer frame 72 through the notch 72c of 72b. When air is sent from the intake / exhaust fan 84 to the exhaust duct 86, the air is blown out from the exhaust ports 86 b to the inner rear side of the outer frame 72.

  Further, one end 85a of the intake duct 85 and one end 86a of the exhaust duct 86 are connected to the intake / exhaust fan 84, and the other side end 85f of the intake duct 85 and the other side of the exhaust duct 86 are connected. The end portions 86c are connected to each other, whereby the intake / exhaust fan 84, the intake duct 85, and the exhaust duct 86 are integrated.

  In the paper feeding device 71 having such a configuration, as shown in the schematic cross-sectional view of FIG. 8, the paper bundle is placed on the paper stacking base 74, and the paper bundle is placed on the column portion 76 a of the paper trailing edge guide 76 and the outer frame. The paper sheet is sandwiched between the assist ducts 77 and 78 and positioned. Then, each winding pulley 89 is rotated in the clockwise direction by the pulse motor 92 to raise the paper stacking base 74, and the uppermost recording paper in the paper bundle is positioned at a predetermined height.

  Also, air is sent from the intake / exhaust fan 84 to the exhaust duct 86, and the air is blown from the exhaust holes 86b of the exhaust duct 86 to the upper layer of the front end surface of the sheet bundle so that the air enters between the recording sheets. Disperse the recording paper.

  In addition, air is sent from the assist fans 79 and 80 to the assist ducts 77 and 78, and the air is blown from the outlets 77 a and 78 a of the assist ducts 77 and 78 to the upper layers on both side end surfaces of the sheet stack on the sheet stacking board 74. The air is blown in between the recording sheets to disperse the recording sheets. At this time, as shown in FIG. 4, the outlets 77a and 78a of the assist ducts 77 and 78 are not shifted from each other in the direction parallel to the both end surfaces of the sheet bundle (the direction parallel to the drawing direction E). A direction in which the air intrusion portion from one outlet 77a and the air intrusion portion from the other exhaust port 78a on the paper surface of the sheet bundle on the paper stacking base 74 are parallel to both side end surfaces of the paper bundle (drawing direction E and Are parallel to each other and the air enters a wide range between the recording sheets, and the deviation of the distribution of the air intrusion amount on the sheet surface of the sheet bundle is reduced, so that the recording sheets vary well.

  FIG. 9A schematically shows the positional relationship between the outlets 77a and 78a and the sheet bundle. As shown in FIG. 9A, the outlets 77a and 78a are not opposed to each other in the direction parallel to the both side end faces wa of the sheet bundle W (the direction parallel to the drawing direction E). The airs Ka and Kb blown from 77a and 78a are blown to different positions on both side end faces wa of the sheet bundle W. For this reason, as shown in FIG. 9B, air enters the entire gap between the recording sheets Pa1 and Pa2 of the sheet bundle W, so that the recording sheets Pa1 and Pa2 are well separated.

  On the other hand, conventionally, as shown in FIG. 10A, air is blown to the same position on both side end faces wa of the sheet bundle W (the same position in the direction parallel to the both end faces wa of the sheet bundle W). Accordingly, the distribution of the air intrusion amount is biased on the sheet surface of the sheet bundle W. For this reason, as shown in FIG. 10B, air intensively enters a specific part between the recording sheets Pa1 and Pa2 of the sheet bundle W, and the recording papers Pa1 and Pa2 are separated at the specific part. In this case, the recording papers Pa1 and Pa2 remain in close contact with each other at the end portions, and this causes the double feeding of the recording papers.

  In this way, air is blown from the exhaust holes 86b of the exhaust duct 86 to the upper layer of the front end surface of the sheet bundle, and from the outlets 77a and 78a of the assist ducts 77 and 78 to different positions on both end surfaces of the sheet bundle. Air is blown to allow air to enter between the recording sheets so that the recording sheets are well dispersed.

  In this state, air is sucked from the intake duct 85 to the intake / exhaust fan 84, and each of the rollers 82 is sucked through the air suction ports 94 on the air holes 81a of the sheet conveying belt 81 and the lower surface 85g of the intake duct 85. , 83 are rotated intermittently, and the respective paper transport belts 81 are intermittently moved around, the recording paper is attracted to the surface of each paper transport belt 81, and the recording paper is pulled out by each paper transport belt 81. E is pulled to E and conveyed to the conveyance roller pair 31 of the image forming apparatus 1, the recording sheet is conveyed through the sheet conveyance path 33, and then the next recording sheet is adsorbed on the surface of each sheet conveyance belt 81. The recording paper is pulled out in the drawing direction E by the paper transport belt 81 and transported to the transport roller pair 31. Thereafter, the recording paper is sucked onto the surface of each paper transport belt 81 in the same manner. Is, the recording sheet by the sheet conveying belt 81 is gradually is transported drawn in the drawing direction E.

  As described above, in the first embodiment, the outlets 77a and 78a of the assist ducts 77 and 78 are not opposed to each other in the direction parallel to the both end surfaces of the sheet bundle (the direction parallel to the drawing direction E). Air is blown to different positions on both end surfaces of the sheet bundle, air enters a wide area between each recording sheet, and the deviation of the distribution of the air intrusion amount on the sheet surface of the sheet bundle is reduced. Each recording sheet varies well, and it is possible to effectively prevent double feeding of recording sheets.

  Further, since air is blown from the exhaust holes 86b of the exhaust duct 86 to the upper layer of the front end surface of the sheet bundle, the recording sheets are more favorably dispersed, and the multi-feeding of the recording sheets can be more effectively prevented. Can do.

  If a large number of outlets 77a, 78a of the assist ducts 77, 78 are arranged in a direction parallel to the both side end faces (direction parallel to the drawing direction E) of the sheet bundle, air is spread over a wide range of both end faces of the sheet bundle. However, in this case, the air volume and the wind speed from the outlet are lowered, and it is difficult for air to enter between the recording sheets. Alternatively, it is necessary to increase the size of each of the assist fans 79 and 80, and thus the size of the paper feeding device 71 and the image forming apparatus 1 is increased. On the other hand, in the first embodiment, since the number of outlets 77a and 78a of the assist ducts 77 and 78 is suppressed, the air volume and the wind speed from the outlets 77a and 78a are not reduced, and each There is no need to increase the size of the assist fans 79 and 80.

  Next, a modification of the sheet feeding device according to the first embodiment will be described. FIG. 11 is a plan view schematically showing a modification of the sheet feeding device of the first embodiment.

  In this modification, the assist ducts 77 and 78 are moved in a direction parallel to the pull-out direction E in conjunction with the column portion 76 a of the paper trailing edge guide 76. Specifically, on the lower surface side of the bottom plate 73, the rack gears 114 are connected to the lower ends of the assist ducts 77 and 78, the rack gears 114 are engaged with the pinion gears 115, and the assist ducts 77 and 78 are connected to each other. The assist ducts 77 and 78, the rack gears 114, and the pinion gear 115 are supported on the same frame 116 together with the column part 76 a of the paper rear end guide 76, and the frame 116 is pulled out. The assist ducts 77 and 78 are supported so as to be movable in a direction parallel to the direction E, so that the assist ducts 77 and 78 are moved in a direction parallel to the drawing direction E in conjunction with the paper rear end guide 76. In this case, when the sheet trailing edge guide 76 contacts the trailing edge of the sheet bundle and is positioned at a position corresponding to the size of the recording sheet, the positions of the outlets 77a and 78a of the assist ducts 77 and 78 are also recorded on the recording sheet. It is set appropriately according to the size of the.

  Next, a paper feeder according to the second embodiment will be described. FIG. 12 is a perspective view showing the sheet feeding device of the second embodiment with the sheet drawer 75 removed, as viewed obliquely from the rear. Note that, in FIG. 12, the same reference numerals are given to portions that perform the same functions as those in FIG.

  The sheet feeding device of the second embodiment is different from the sheet feeding device 71 of the first embodiment in that the assist ducts 101 and 102 are applied instead of the assist ducts 77 and 78 of FIG. Differently, the other configuration is the same as that of the sheet feeding device 71 of the first embodiment.

  Each assist duct 101, 102 has a lower base portion 101a, 102a and an upper duct body 101b, 102b, respectively. The lower base portions 101a and 102a are disposed in the recesses 74b on both sides of the paper stacking base 74, supported on both sides of the bottom plate 73 so as to be reciprocally movable in a direction perpendicular to the drawing direction E, and approaching each other. The upper duct bodies 101b and 102b are also moved together with the lower base parts 101a and 102a. Accordingly, it is possible to position the sheet bundle by sandwiching both ends of the sheet bundle between the assist ducts 101 and 102.

  Further, each of the upper duct bodies 101b and 102b is supported so as to be movable in a direction parallel to both side end surfaces of the sheet bundle (a direction parallel to the drawing direction E) with respect to each of the lower base portions 101a and 102a. As shown in the sectional view of FIG. 13, a trapezoidal groove (arimiso) 103 is formed on the upper end surface of each lower base portion 101a, 102a, and a trapezoidal crosspiece (arigata) 104 is formed on the lower end surface of each upper duct body 101b, 102b. The trapezoidal bars 104 of the upper duct bodies 101b and 102b are movably inserted into the trapezoidal grooves 103 of the lower base parts 101a and 102a. A rack gear (not shown) is formed on the lower surface of the trapezoidal bar 104 of each upper duct body 101b, 102b, each motor 105 is provided on the side wall of each lower platform 101a, 102a, and the output shaft of each motor 105 is provided. The pinion gear 106 of the output shaft of each motor 105 is meshed with the rack gear of the trapezoidal bar 104 of each upper duct body 101b, 102b by being introduced into the lower base parts 101a, 102a. When the motors 105 are driven to rotate, the respective pinion gears 106 rotate, and the rack gears of the trapezoidal crosspieces 104 of the upper duct bodies 101b and 102b reciprocate in a direction parallel to the both end surfaces of the sheet bundle, as shown in FIG. As shown in FIG. 4, the upper duct bodies 101b and 102b reciprocate on the lower base parts 101a and 102a.

  Moreover, each upper duct main body 101b, 102b is a hollow body, has a ventilation path therein, and is connected to the exhaust ports of the assist fans 79, 80. Air sucked by each of the assist fans 79 and 80 is sent into the ventilation path of each upper duct body 101b and 102b, and this air enters the inside of the outer frame 72 from the outlets 101c and 102c of each upper duct body 101b and 102b. It is blown out.

  Here, as shown in FIG. 12, in a state where the upper duct bodies 101b and 102b are overlapped with the lower base parts 101a and 102a, the outlets 101c and 102c of the upper duct bodies 101b and 102b are on both sides of the sheet bundle. They are not offset from each other in the direction parallel to the end face (the direction parallel to the drawing direction E).

  In this state, air is sent from the assist fans 79 and 80 to the ventilation paths of the upper duct bodies 101b and 102b, and the air is sent from the outlets 101c and 102c of the upper duct bodies 101b and 102b to the sheet on the sheet stacking board 74. The air is blown onto the upper layer on the both end surfaces of the bundle so that air enters between the recording sheets and the recording sheets are dispersed.

  At the same time as the air is sent by the assist fans 79 and 80, the motors 105 are driven to rotate so that the upper duct bodies 101b and 102b are parallel to the both end surfaces of the sheet bundle on the lower base parts 101a and 102a. Reciprocate in the same direction at the same speed in the direction. As a result, as shown in FIG. 15, the air outlets 101c and 102c of the upper duct bodies 101b and 102b reciprocate while being displaced from each other, and the air Ka and Kb blown from the air outlets 101c and 102c become the sheet bundle W. Are sprayed at different positions on both side end faces wa and in a wide range. For this reason, air quickly enters the entire gap between the recording sheets of the sheet bundle W, and the recording sheets are separated better.

  Next, a modification of the sheet feeding device according to the second embodiment will be described. FIG. 16 is a perspective view illustrating a modified example of the sheet feeding device according to the second embodiment when viewed obliquely from the rear. In FIG. 16, the same reference numerals are given to the portions that perform the same functions as those in FIG. 12.

  In this modification, the air outlets 101c and 102c are formed at the center of the inner wall of each upper duct body 101b and 102b, and the positions of the upper duct bodies 101b and 102b are parallel to the both end faces of the sheet bundle (drawer). The outlets 101c and 102c of the upper duct bodies 101b and 102b are shifted from each other in a direction parallel to the direction E).

  At the same time as the air is sent by the assist fans 79 and 80, the motors 105 are driven to rotate so that the upper duct bodies 101b and 102b are parallel to the both end surfaces of the sheet bundle on the lower base parts 101a and 102a. Move in the same direction and reciprocate in the opposite direction. In this case, as shown in FIG. 17, the outlets 101c and 102c of the upper duct bodies 101b and 102b repeatedly pass each other. However, except for this passing, the outlets 101c and 102c are on both sides of the sheet bundle. The air Ka and Kb blown from the outlets 101c and 102c are shifted from each other in the direction parallel to the end face (the direction parallel to the pull-out direction E), and in a wide range at different positions on the both end faces wa of the sheet bundle W. Be sprayed on. For this reason, air quickly enters the entire gap between the recording sheets of the sheet bundle W, and the recording sheets are separated better.

  In the second embodiment and the modified example, the upper duct bodies 101b and 102b of the assist ducts 101 and 102 are moved in a direction parallel to both end faces of the sheet bundle (a direction parallel to the drawing direction E). Although the outlets 101c and 102c of the upper duct main bodies 101b and 102b are moved, you may move an outlet using another structure. For example, as shown in FIG. 18, a plurality of air outlets 117 are formed on the inner wall of the assist duct side by side in a direction parallel to both end faces of the sheet bundle (a direction parallel to the drawing direction E). Air can be blown out from either. Then, the slide plate 118 is reciprocated in a direction parallel to the both end surfaces of the sheet bundle while being in sliding contact with the inner wall surface of the assist duct, and the openings 118a of the slide plate 118 are sequentially stacked on the air outlets 117, The air blowing port 117 is selectively opened, and air is blown out only from the opened air blowing port 117. Thereby, air can be blown over a wide range of the side end surfaces of the sheet bundle.

  Further, the assist ducts 101 and 102 are omitted, and the assist fans 79 and 80 are connected to both end surfaces of the sheet bundle in a state where the exhaust ports (blowing ports) of the assist fans 79 and 80 are directed to both end surfaces of the sheet bundle. You may reciprocate in a parallel direction.

  Further, only one of the assist ducts 101 and 102 or one of the assist fans 79 and 80 may be moved and the other may be fixed. Alternatively, the moving speeds of the assist ducts 101 and 102 or the assist fans 79 and 80 may be varied.

  Next, a paper feeder according to a third embodiment will be described. FIG. 19 is a perspective view showing the sheet feeding device according to the third embodiment in a state in which the sheet drawing portion 75 is removed as viewed obliquely from the rear. In FIG. 19, the same reference numerals are given to portions that perform the same operation as in FIG. 4.

  Compared with the sheet feeding device 71 of the first embodiment, the sheet feeding device of the third embodiment replaces the assist ducts 77 and 78 of FIG. 4 with each assist duct 121 and 122 and each fixed louver 123 and 124. The other configuration is the same as that of the sheet feeding device 71 of the first embodiment.

  As with the assist ducts 77 and 78, the assist ducts 121 and 122 are supported on both sides of the bottom plate 73 so as to be reciprocally movable in a direction orthogonal to the pull-out direction E, and are they moved so as to approach each other? Alternatively, the paper sheets are moved so as to be separated from each other, and the both ends of the sheet bundle are sandwiched and positioned.

  Each of the assist ducts 121 and 122 is formed with an air outlet 121a and 122a, and each of the air outlets 121a and 122a is provided with a fixed louver 123 and 124, respectively. Furthermore, the exhaust ducts of the assist fans 79 and 80 are connected to the assist ducts 121 and 122, respectively.

  The air outlets 121a and 122a of the assist ducts 121 and 122 are at the same position in the direction parallel to the both end surfaces of the sheet bundle (the direction parallel to the drawing direction E) and face each other. Each wing plate of one fixed louver 123 is arranged in parallel so as to be along an obliquely rearward direction (backward is the direction opposite to the pulling direction E), and from the exhaust port of one assist fan 79 to the assist duct 121. When air is sent into the ventilation path, this air is guided obliquely backward by the fixed louver 123 of the air outlet 121a and blows out. In addition, the wing plates of the other fixed louver 124 are arranged in parallel so as to be directed diagonally forward (the front is the drawing direction E), and the ventilation path of the assist duct 122 from the exhaust port of the other assist fan 79. When air is fed into the air, the air is guided obliquely forward by the fixed louver 124 of the air outlet 122a and blows out.

  Therefore, as shown in FIG. 20, the air Ka guided by one fixed louver 123 and blown obliquely backward and the air Kb guided by the other fixed louver 124 and blown obliquely forward are both end surfaces of the sheet bundle W. The wa are sprayed at different positions of wa, and air enters the entire gap between the recording sheets of the sheet bundle W, so that the recording sheets are separated satisfactorily.

  Next, a paper feeder according to a fourth embodiment will be described. FIG. 21 is a plan view schematically showing a sheet feeding device according to the fourth embodiment. Note that, in FIG. 21, the same reference numerals are given to portions that perform the same operation as in FIG.

  The sheet feeder of the fourth embodiment is different from the sheet feeder of the third embodiment in that each movable louver 131, 132 is applied instead of each fixed louver 123, 124 of FIG. .

  Each of the movable louvers 131 and 132 is configured such that each wing plate is rotatably supported, and each wing plate is connected by a link mechanism. When the link mechanism is displaced by a respective motor (not shown), Each slat rotates together in the same direction around their axes.

  For example, as shown in FIG. 22 (a), each air Ka blown out from the exhaust port of each assist fan 79, 80 by reciprocally rotating each louver of each movable louver 131, 132 in the same direction at the same speed, Change the direction of Kb. In this case, the directions of the airs Ka and Kb are repeatedly and temporarily opposed to each other. However, the directions of the airs Ka and Kb are deviated from each other, and the air Ka and Kb are not in the sheet bundle W. It sprays on the position which both sides end surface wa mutually differs in a wide range. For this reason, air quickly enters the entire gap between the recording sheets of the sheet bundle W, and the recording sheets are well separated.

  Alternatively, as shown in FIG. 22 (b), the air blast plates of the movable louvers 131 and 132 are reciprocally rotated in opposite directions at the same speed, and the air blown out from the exhaust ports of the assist fans 79 and 80. The directions of Ka and Kb may be changed. In this case as well, the directions of the airs Ka and Kb repeatedly pass each other. However, except for the case of the passing, the directions of the airs Ka and Kb are shifted from each other so that the air Ka and Kb are on both sides of the sheet bundle W. The recording sheets are sprayed at different positions on the end face wa and in a wide range, and the recording sheets of the sheet bundle W are well separated.

  In addition, without using each movable louver 131 and 132, each assist fan 79 and 80 is reciprocated around a vertical axis, and the direction of the exhaust port (blow-out port) of each assist fan 79 and 80 is changed. The direction of each air blown from the exhaust ports of the fans 79 and 80 may be changed.

  Further, either one of the movable louvers 131 and 132 may be replaced with a fixed louver. Alternatively, the rotational speeds of the blades of the movable louvers 131 and 132 may be varied.

  Further, the position of the air outlet and the direction of the air that has been blown out may be changed by appropriately combining the above embodiments and modifications.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. It is understood.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Document reader 11 Printing part 12 Paper conveyance part 13 Paper supply part 14 Large capacity paper feed cassette (LCC)
33 Paper transport path 71 Paper feeder 72 Outer frame 73 Bottom plate 74 Paper stacking base 75 Paper drawer (paper transport)
76 Paper rear edge guide (contact part)
77, 78, 101, 102, 121, 122 Assist duct (air blowing part)
77a, 78a, 101c, 102c, 121a, 122a Air outlet 79, 80 Assist fan 81 Paper transport belt (paper transport member)
82, 83 Roller 84 Intake / exhaust fan 85 Intake duct 86 Exhaust duct 103 Trapezoidal groove (displacement part)
104 Trapezoidal bar (displacement part)
105 Motor (displacement part)
106 Pinion gear (displacement part)
123, 124 Fixed louver 131, 132 Movable louver (displacement part)

Claims (9)

A sheet stacking table on which a sheet bundle is loaded, air is sucked through a vent hole of a sheet conveying member, the sheets of the sheet bundle are adsorbed to the sheet conveying member, and the sheet is conveyed to the sheet conveying path by the sheet conveying member. And a paper transport unit for transporting,
A plurality of air blowing portions for blowing air to both end surfaces of the sheet bundle;
The sheet feeding device according to claim 1, wherein air blowing positions on both side end faces of the sheet bundle to which air is blown by the air blowing sections are shifted from each other in a direction parallel to both side end faces of the sheet bundle. The sheet feeding device according to claim 1,
Each of the air blowing portions includes a blowout port for blowing air to the side end surface of the sheet bundle,
A paper feeding device, wherein the positions of the respective outlets are shifted from each other in a direction parallel to both end faces of the sheet bundle. The sheet feeding device according to claim 2,
A sheet feeding device comprising: a displacement unit configured to displace the position of each outlet in a direction parallel to both end surfaces of the sheet bundle. The sheet feeding device according to claim 3,
The sheet feeding device, wherein the displacement unit displaces the position of each outlet in the same direction parallel to both end faces of the sheet bundle. The sheet feeding device according to claim 3,
The sheet feeding device, wherein the displacement unit displaces the positions of the outlets in opposite directions parallel to both end surfaces of the sheet bundle. The sheet feeding device according to any one of claims 3 to 5,
A contact portion that moves in a direction parallel to both end surfaces of the sheet bundle on the sheet stacking table, contacts the rear end face of the sheet bundle, and positions the sheet bundle;
The displacement portion displaces the position of each outlet in a direction parallel to the both side end surfaces of the sheet bundle in conjunction with the movement of the contact portion in a direction parallel to the both side end surfaces of the sheet bundle. Characteristic paper feeder. The sheet feeding device according to claim 1,
Each of the air blowing portions includes a blowout port for blowing air to the side end surface of the sheet bundle,
A sheet feeding device characterized in that the air blowing direction from each of the blowing ports is directed to each of the air blowing positions. The sheet feeding device according to claim 7,
A sheet feeding device comprising a displacement portion that displaces the blowing direction of air from each of the blowing ports.   An image forming apparatus comprising the paper feeding device according to claim 1.

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