JP2004352396A - Sheet feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To feed sheets by air to constantly favorably separate sheets regardless of kinds and/or size of the sheets. <P>SOLUTION: Air is blown to a sheet stacking unit 12, and the uppermost sheet S on the sheet stacking unit is separated by the air. When the uppermost sheet is sucked to be carried to a carrying passage, the air blowing direction is varied to correspond to at least either the kind or the size of the sheet. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet feeding apparatus used in an image forming apparatus such as a copying machine, a facsimile, or a printer, and more particularly to a sheet feeding apparatus that feeds a sheet-shaped recording medium using air.
[0002]
[Prior art]
Generally, in an image forming apparatus, a toner image formed on an image carrier such as a photosensitive drum is transferred to a sheet-like recording medium (hereinafter simply referred to as a sheet) at a transfer position to form an image. Is fed from a sheet feeding device to a transfer position via a sheet conveying path.
[0003]
As a sheet feeding device, for example, air is blown on a sheet stacked on a sheet stacking table such as a sheet feeding tray, so that the sheets on the sheet stacking table float up, and the sheets are separated one by one (after ), There is a sheet in which the uppermost sheet is sucked (sucked) to a feeding belt (conveying belt) and fed.
[0004]
In such a sheet feeding apparatus, an air duct (blowing duct) for blowing air to the sheet on the sheet stacking table is provided, and in order to satisfactorily separate the sheet according to the size of the sheet and the like, Although it is necessary to change the outlet shape of the blowing duct according to the sheet size or the like, if the outlet shape is changed according to the sheet size or the like, it is necessary to replace the blowing duct itself according to the sheet size or the like.
[0005]
On the other hand, even if the leading end of the sheet is curled, the leading end of the nozzle is always swung so as to face the leading edge of the uppermost sheet before floating in order to feed the sheet stably. There is one in which the direction of the nozzle is changed in accordance with the curl of the leading end of the sheet so that the curled sheet floats favorably (see Patent Document 1).
[0006]
Furthermore, in order to reliably separate the uppermost sheet and prevent double feed, when feeding the uppermost sheet to the sheet feed belt by suction with the sheet feed belt provided with air suction means inside, A retard member protruding inward (upward) of the paper feed belt from the contact surface of the paper feed belt with the paper is provided between the paper feed belts, and a plurality of papers are attracted to the paper feed belt. In addition, the retard member abuts on the sheet adsorbed from the lower side from the lower side to provide conveyance resistance, and prevents feeding of the second and subsequent sheets having a weak suction force to the sheet feeding belt, thereby preventing double feeding. (See Patent Document 2).
[0007]
[Patent Document 1]
JP-A-10-120214 (paragraphs (0042) to (0057), FIGS. 1 to 5)
[Patent Document 2]
JP 2001-233487 A (paragraphs (0035) to (0045), FIG. 2 to FIG. 5)
[0008]
[Problems to be solved by the invention]
By the way, in the sheet feeding device described in Patent Literature 1, the tip of the nozzle is swung so as to face the leading edge of the uppermost sheet before floating, so as to match the curl of the sheet leading end, Although it is shown that the direction of the nozzle is changed, simply change the direction of the nozzle according to the curl of the leading edge of the sheet so that even if the leading edge of the sheet is curled, feed the stable sheet However, if the sheet size or the like is different, the separability is reduced, the sheet cannot be separated well, and as a result, problems such as double feeding of the sheet may occur. .
[0009]
Further, in the sheet feeding device described in Patent Literature 2, the retard member applies conveyance resistance to the second and subsequent sheets to prevent double feeding, but if the sheet size or the like is different, Even if the separation property of the sheet is reduced and the conveyance resistance is given by the retard member, double feeding may occur.
[0010]
SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding apparatus capable of always performing good sheet separation regardless of a sheet type and / or size.
[0011]
[Means for Solving the Problems]
According to the present invention, there is provided a sheet feeding apparatus for sending out a top sheet from a sheet stacking unit on which a plurality of sheets are stacked to a conveyance path, wherein the sheet stacking unit is blown with air and the sheet stacking unit is blown by the air. Separating means for separating the uppermost upper sheet, and a transport unit disposed above the uppermost sheet, for sucking the uppermost sheet and transporting the uppermost sheet to the transport path, wherein the separating means is A sheet feeding device is characterized in that the air blowing direction is changed according to at least one of the type and size of the sheet.
[0012]
In this way, by changing the air blowing direction according to at least one of the type and size of the sheet and separating the stacked sheets, it is possible to always perform the best irrespective of the type or size of the sheet. The upper sheet can be separated, and troubles such as double feeding do not occur.
[0013]
In the present invention, the separating unit has a wind direction regulating unit that changes a blowing direction of the air in a sheet stacking direction. For example, the wind direction regulating unit extends in a direction orthogonal to the sheet stacking direction. The air direction restricting part is rotatable around the fulcrum, and the air blowing direction is changed.
[0014]
Further, in the present invention, the separating unit has a wind direction restricting unit that changes a blowing direction of the air in a direction orthogonal to the sheet stacking direction. For example, the wind direction restricting unit includes a sheet stacking direction. The wind direction restricting portion is rotatable around the fulcrum to change the air blowing direction.
[0015]
Further, according to the present invention, the separation means rotates around a fulcrum extending in a direction orthogonal to the sheet stacking direction and around a fulcrum parallel to the sheet stacking direction. A second wind direction regulating section may be provided, and the first and second wind direction regulating sections may be rotated around the fulcrum to change the air blowing direction.
[0016]
In this way, the first wind direction restricting portion is rotated about a fulcrum extending in a direction orthogonal to the sheet stacking direction, and the second wind direction restricting portion is rotated about a fulcrum parallel to the sheet stacking direction. By changing the air blowing direction, the uppermost sheet can be satisfactorily separated with a simple configuration regardless of the sheet type and size.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be illustratively described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention to them unless otherwise specified, and are merely mere descriptions. This is just an example.
[0018]
First, referring to FIG. 1, the illustrated sheet feeding apparatus is used when an image forming apparatus feeds sheets one by one from a sheet mounting table such as a sheet feeding tray to a sheet conveying path. The sheet is transported to an image forming unit (not shown) via a sheet transport path, where a toner image formed on an image carrier such as a photosensitive drum is transferred onto the sheet. (Not shown), where the toner image is fixed, and is discharged to a discharge tray or the like via a discharge path.
[0019]
The sheet feeding device is an air sheet feeding device, and includes a transport unit 11. The transport unit 11 is a sheet stacking table (sheet stacking unit) such as a sheet feeding tray on which a plurality of sheets S are stacked. 12 is arranged above. Each time the sheet S is fed, the bottom surface of the sheet stacking table 12 moves upward to position the uppermost sheet S at a predetermined position.
[0020]
The transport unit 11 includes a unit frame (not shown), and a transport belt unit (suction belt unit) 13 is supported on the unit frame. The transport belt section 13 includes a drive roller 14 and a driven roller 15, and a transport belt 16 is stretched between the drive roller 14 and the driven roller 15. Then, a driving force is applied to the drive roller 14 from a drive source such as a motor. When the drive roller 14 rotates, the transport belt 16 rotates in a direction indicated by a solid arrow.
[0021]
As shown in the drawing, a suction duct 17 is provided in the transport belt portion 13, and a plurality of suction ports 17 a are formed on the lower surface side of the suction duct 17, and when suction is performed by the suction duct 17. The uppermost sheet S of the sheet stacking unit 12 is sucked by the conveyor belt unit 13 and is conveyed in the direction indicated by the dashed arrow in the drawing, and the sheet S is sent to the image forming unit via a conveyance path (not shown). Will be.
[0022]
On the downstream side in the sheet feeding direction, an air duct section (blowing duct section) 18 is disposed with its outlet 18a facing the sheet stacking unit 12 side, and the sheet blown by the air blown from the blowing duct section 18. The uppermost sheet among the sheets stacked on the placement unit 12 is separated (sorted). That is, the air from the blowing duct portion 18 is blown toward the sheet stacking table 12, and the blown air separates the sheets S stacked on the sheet stacking table 12 one by one. Then, the uppermost sheet is sucked by the conveying belt unit 13, conveyed in the sheet feeding direction, and sent to the image forming unit via the sheet conveying path as described above.
[0023]
Here, referring to FIG. 2, a wind direction regulating member (hereinafter, referred to as a louver member) 19 is attached to an outlet 18 a of the blowing duct portion 18, and the louver member 19 is arranged at a predetermined interval. In the figure, a plurality of horizontal fin bodies (first wind direction regulating portions) 20 extending in the horizontal direction (horizontal direction) and a plurality of vertical fin bodies (first fin bodies) extending in the vertical direction (vertical direction) at predetermined intervals. The horizontal fin body 20 is supported by the inner surfaces of the left and right side walls of the blowing duct 18 so as to be rotatable in the vertical direction. On the other hand, the vertical fin body 21 is rotatably supported on the inner surfaces of the upper and lower walls of the blowing duct 18 in the left-right direction.
[0024]
In the illustrated example, three horizontal fin bodies 20 are provided, and nine vertical fin bodies 21 are provided. The distance from the leftmost vertical fin body 21 to the rightmost vertical fin body 21 in the drawing corresponds to the maximum size (for example, A3 size) of a sheet used in the image forming apparatus.
[0025]
The rotation shaft of a horizontal fin body (hereinafter, referred to as a center horizontal fin body) 20 located at the center of the horizontal fin body 20 is connected to a rotation shaft 22a of a motor 22 attached to the inner surface of the right side wall of the blowing duct portion 18. Further, the rotation shaft 22 a is connected to the rotation shaft of the remaining horizontal fin body 20 via the belt body 23.
[0026]
Therefore, by rotating the motor 22 forward or backward, all the horizontal fin bodies 20 rotate around the rotation axis in the same direction (upward or downward direction), and change the direction of the blowing air to, for example, Can be changed downward.
[0027]
Here, referring also to FIG. 3, as shown in FIG. 3, the vertical fin body 21 is supported on the inner surface of the quality wall and the inner surface of the upper wall of the blowing duct portion 18 by the operating shaft 21a and the fulcrum shaft 21b, respectively. Reference numeral 21b is located closer to the outlet 18a than the operating shaft 21a. A vertical fin body (hereinafter, referred to as a central vertical fin body) 21 located at the center of the plurality of vertical fin bodies 21 is fixed, for example, in a state shown in FIG. A motor 24 is disposed on the outer surface of the lower wall of the blowing duct 18.
[0028]
On the other hand, the operating shaft 21a of the vertical fin body 21 located to the left of the central vertical fin body 21 is rotatably attached to a first rack member 25 extending leftward in FIG. The operating shaft 21a of the vertical fin body 21 located to the right of 21 is rotatably attached to a second rack 26 extending leftward in FIG.
[0029]
Here, with reference to FIGS. 4A and 4B, FIG. 4A is a view as seen from the upper wall side of the blowing duct 18, and FIG. It is the figure seen from the lower wall side.
[0030]
A pinion 24b is formed on a rotation shaft 24a of the motor 24. The pinion 24b meshes with a rack 25a formed on the first rack member 25 and a rack 26a formed on the second rack member 26. .
[0031]
In FIG. 4B, a rack 25a is formed on one surface (lower side surface in the figure) of the first rack member 25 near the motor 24, and the second rack member 26 is formed of the first rack member 25. It has a central axis (extended axis), a supporting member 26b having the same central axis, and a flange 26c formed at one end (right end in the drawing) of the supporting member 26b. It has a shape. A rack 26a is formed on one surface (upper surface in the figure) of the flange portion 26c, and the rotation shaft 24a of the motor 24 is inserted into a space defined by the racks 25a and 26a, and the pinion 24b meshes with the racks 25a and 26a. ing.
[0032]
Further, as shown in FIG. 4A, on the upper wall surface of the blowing duct portion 18, on the side of the vertical fin body 21 supported by the first rack member 25, a long hole 27 extending diagonally to the upper left in the figure. On the side of the vertical fin body 21 supported by the second rack member 26, elongated holes 28 extending obliquely rightward in the figure are formed, and the fulcrum shafts 21b are inserted into these elongated holes 27 and 28, respectively. The fulcrum shaft 21b is movable along the elongated hole 27 or 28.
[0033]
As a result, when the first and second rack members 25 and 26 move in the directions indicated by solid arrows by the driving of the motor 24, the fulcrum shaft 21b side of the vertical fin body 21 moves in the direction indicated by the broken arrows. As a result, the vertical fin bodies 21 rotate around the central vertical fin body 21 (not shown in FIGS. 4A and 4B) in directions facing each other. Then, the blowing air is collected in a direction centered on the central vertical fin body 21.
[0034]
On the other hand, when the first and second rack members 25 and 26 move in the direction opposite to the direction indicated by the solid line arrow (see FIG. 4A) by the drive of the motor 24, the fulcrum shaft 21b side of the vertical fin body 21 The vertical fin body 21 moves in the direction opposite to the direction shown by the broken line arrow (see FIG. 4B), so that the vertical fin bodies 21 rotate away from each other about the central vertical fin body 21.
[0035]
The driving of the motors 22 and 24 is controlled by a control device (not shown). Now, when performing image formation, when a sheet type and a size are selected (hereinafter simply referred to as “sheet selection”) from an operation panel provided in the image forming apparatus main body, a sheet corresponding to the sheet selection is selected. Sheets are fed from a sheet stacking unit that stacks sheets.
[0036]
In the control device, the position of the horizontal fin body and the position of the vertical fin body according to the sheet type and size are set in advance as fin body position setting information, and this fin body position setting information is set according to the sheet type and size. Indicates the position where the sheet separation property becomes the best.
[0037]
The control device reads the fin body position setting information in accordance with the sheet selection, controls the driving of the motors 22 and 24 based on the fin body position setting information, and sets the orientation of the horizontal fin body 20 and the vertical fin body 21 to the sheet type and the sheet type. Change according to size.
[0038]
For example, when the sheet size is small, the vertical fin body 21 is directed toward the center vertical fin side, and the blowing air is collected toward the center of the sheet. When the sheet type is thick paper or the like, the blowing air is blown downward with the horizontal fins 20 facing downward to deal with the weight of the sheet.
[0039]
In any case, the driving of the horizontal fin body 20 and the vertical fin body 21 is controlled in accordance with the sheet type and the sheet size, and the blowing air is blown in the direction most suitable for the sheet type and the sheet size. Good separability can always be obtained regardless of the size.
[0040]
In the above-described example, the one having the horizontal fin body 20 and the vertical fin body 21 as the wind direction regulating member has been described. However, one of the horizontal fin body 20 and the vertical fin body 21, preferably, only the horizontal fin body 20 is provided. Thus, it has been found that if the drive of the horizontal fin body 20 or the vertical fin body 21 is controlled in accordance with at least one of the sheet type and the size, the separability can be improved irrespective of the sheet type or the size.
[0041]
Further, as shown in FIG. 5, the wind direction regulating member includes only the above-described horizontal fin body 20, and a guide rail 31 extending in the horizontal direction is formed in the outlet 18 a on the front side of the horizontal fin body 20, The wind direction regulating plate 32 may be inserted into the guide rail 31 to replace the vertical fin body 21 described above. In other words, a plurality of wind direction regulating plates 32 having different shapes of the outlet array patterns 32a according to the sheet type and / or size are prepared, and the wind direction regulating plate 32 according to the sheet type and / or size is attached to the guide rail 31. To adjust the wind direction in the left-right direction.
[0042]
【The invention's effect】
As described above, according to the present invention, the direction of air blowing is changed according to at least one of the type and size of the sheet to separate the stacked sheets. Irrespective of this, the uppermost sheet can always be satisfactorily separated, and as a result, there is an effect that problems such as double feeding do not occur.
[0043]
According to the present invention, the air direction restricting portion is rotated around a fulcrum extending in a direction perpendicular to the sheet stacking direction to change the air blowing direction, so that the sheet type and / or size can be changed with a simple configuration. Regardless of this, there is an effect that the uppermost sheet can be satisfactorily separated.
[0044]
In the present invention, since the air direction restricting portion is rotated around the fulcrum parallel to the sheet stacking direction to change the air blowing direction, the simple configuration can be used regardless of the sheet type and / or size. There is an effect that the upper sheet can be satisfactorily separated.
[0045]
In the present invention, the first wind direction regulating portion is rotated around a fulcrum extending in a direction perpendicular to the sheet stacking direction, and the second wind direction regulating portion is rotated around a fulcrum parallel to the sheet stacking direction. Since the air blowing direction is changed, there is an effect that the uppermost sheet can be satisfactorily separated with a simple configuration regardless of the sheet type and size.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing an example of a sheet feeding apparatus according to the present invention.
FIG. 2 is a view showing a wind direction regulating member provided on the outlet side of the blowing duct portion shown in FIG. 1 from the outlet side.
FIG. 3 is a side view, partially broken away, of a wind direction regulating member provided on the blow-out opening side of the blowing duct section shown in FIG. 1;
4A and 4B are diagrams for explaining the movement of the vertical fin shown in FIG. 2, wherein FIG. 4A is a diagram viewed from above and FIG. 4B is a diagram viewed from below.
FIG. 5 is a view schematically showing another example of the sheet feeding apparatus according to the present invention.
[Explanation of symbols]
11 Transport unit 12 Sheet loading table (sheet loading unit)
13 Transport belt section (suction belt section)
14 Drive roller 15 Follower roller 16 Conveyor belt 17 Suction duct 18 Air duct (spray duct)
19 Wind direction regulating member 20 Horizontal fin body 21 Vertical fin body

Claims (6)

A sheet feeding device for sending a top sheet from a sheet stacking unit on which a plurality of sheets are stacked to a conveyance path,
Separating means for blowing air to the sheet stacking unit and separating the top sheet on the sheet stacking unit by the air;
A transport unit disposed above the uppermost sheet and for transporting the uppermost sheet to the transport path by sucking the uppermost sheet;
The sheet feeding device according to claim 1, wherein the separating unit changes a blowing direction of the air according to at least one of a type and a size of the sheet. 2. The sheet feeding device according to claim 1, wherein the separating unit includes a wind direction restricting unit that changes a blowing direction of the air in a stacking direction of the sheets. 3. The wind direction restricting portion is rotatable around a fulcrum extending in a direction orthogonal to the sheet stacking direction,
3. The sheet feeding device according to claim 2, wherein the air direction regulating portion is rotated around the fulcrum to change a direction in which the air is blown. 2. The sheet feeding device according to claim 1, wherein the separation unit includes a wind direction restricting unit that changes a blowing direction of the air in a direction orthogonal to a sheet stacking direction. 3. The wind direction restricting portion is rotatable around a fulcrum parallel to the stacking direction of the sheets,
The sheet feeding device according to claim 4, wherein the air direction restricting portion is rotated around the fulcrum to change a direction in which the air is blown out. A first wind direction restricting portion that rotates around a fulcrum extending in a direction orthogonal to the sheet stacking direction;
A second wind direction regulating portion that rotates around a fulcrum parallel to the sheet stacking direction,
2. The sheet feeding device according to claim 1, wherein the first and second wind direction restricting portions are rotated around the fulcrum to change a direction in which the air is blown out.

Images