JP2006188362A - Automatic document feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem in a conventional automatic document feeder wherein a large number of documents come into a nip point between a feeding belt and a separating belt and the separating roller is rotated following the process of rotation of the feeding belt to disable the separation of the documents. <P>SOLUTION: This automatic document feeder comprises a paper feed means 7 positioned above a document stand 3 on which a document bundle P is placed and picking up the document on the uppermost side of the document bundle P and separating/feeding means 9 and 10 separating and feeding the picked up documents one by one. A stop member 31 brought into contact with the lower surface of the document picked up by the paper feed means 7 to restrict the movement of the document at the bottom part is installed between the paper feed means 7 and the separating/feeding means 9 and 10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder provided in a copying machine, a facsimile machine, a scanner device, and the like, and more particularly, an automatic document take-out from a document table on which a bundle of documents is placed, The present invention relates to an improvement of an original conveying apparatus.

  An automatic document feeder generally includes a paper feed unit, a scan unit, and a paper discharge unit. The scan unit reads a document fed one by one from the paper feed unit, and the read document is discharged from the paper discharge unit. Then, the next original is fed. In the case of a double-sided document, it is reversed by the paper discharge unit, scanned again by the scan unit, and the back side is read, and then discharged from the paper discharge unit.

  An example of such an automatic document feeder is shown in FIG. FIG. 3 is a partial cross-sectional view schematically showing a paper feeding unit and a scanning unit of the automatic document feeder 1 mounted on a copying machine. This automatic document feeder comprises a document table on which a bundle of documents is placed, which is composed of a fixed document table 2 and a movable document table 3 that rotates around a fulcrum 3a (A-B direction in the figure). When a document bundle (not shown) is placed upward, the set feeler 4 is moved by the document bundle, and the set sensor 5 is responsive to detect the document set. When the document set is detected, the movable document table 3 rises and presses the upper surface of the document bundle against the pickup roller 7. The pickup roller 7 is supported so as to be rotatable in the CD direction in the figure, and the movement of the pickup roller 7 is detected by a rise detection sensor 8.

  When the document bundle is placed and the pickup roller 7 is stationary, the pickup roller 7 is driven to sequentially take out the documents from the uppermost surface of the document bundle. The pick-up roller 7 is an example of the paper feeding means referred to in the present invention. The extracted document reaches separation / feeding means including a feeding belt 9 and a separation roller 10 (referred to as a reverse roller). In this separating and feeding means, the feeding belt 9 is stretched around two support rollers 9a and 9b and is rotationally driven by the driving support roller 9a. The support roller 9b is a driven roller. The feeding belt 9 is pressed against the separation roller 10 by contact pressure applying means (not shown), and the original is nipped between the feeding belt 9 and the separation roller 10 and sent out to the pull-out roller 11.

  The document passes from the pull-out roller 11 to the conveyance belt 17 driven by the registration roller 13 and the conveyance belt drive roller 16 through the document conveyance path, is guided onto the contact glass 18, and is scanned by the scanner 19 to be an image on the document surface. Is read. Here, when the pull-out sensor 12 detects a document, the pickup roller 7 is retracted in the upward C direction, and the front and rear ends of the document are detected by the pull-out sensor 12 to measure the length. The size detection sensor 14 detects the width of the document, and the registration sensor 15 detects the length of the document fed by the registration roller 13 and determines the stop position of the document on the contact glass 18. The document scale 20 is provided on the contact glass 18 and presses the document against the document scale 20 to define the scan start position. When the reading of one original is completed, the original is discharged from a paper discharge section (not shown, not shown) to a paper discharge tray, and the next original is fed to sequentially read the original, form an image, and copy.

  In this way, the originals are taken out from the original bundle and processed one by one. Here, the operation of the separating and feeding means by the feeding belt 9 and the separating roller 10 will be described. If the pick-up roller 7 always picks up only one original, this separating / feeding mechanism does not need to operate. However, since the pick-up roller 7 actually takes out two to three originals, It is necessary to separate them so that they are fed one by one. The separation roller 10 is driven in a direction opposite to the moving direction of the feeding belt 9 via a torque limiter. Assuming that one original is nipped between the feeding belt 9 and the separation roller. If there is, the separation roller 10 is pulled by the frictional force with the original fed by the feeding belt 9 and is rotated in the moving direction of the feeding belt 9, but when two or more originals are nipped, the separation roller 10 is separated. The document on the 10 side slips, the torque applied to the separation roller 10 disappears, rotates in the direction opposite to the original driving direction, that is, the moving direction of the feeding belt 9, and pulls back the document at the bottom of the document bundle. As a result, even if a plurality of documents are fed, they are separated one by one in front of the nip point. Such separation and feeding means can be found in Patent Document 1 and Patent Document 2.

JP-A-11-217126 JP-A-11-222326

  By the way, in such a separating and feeding mechanism, when the coefficient of friction between the documents is large, or when about 10 documents are accidentally sent to the nip point between the feeding belt and the separation roller, the separation and feeding mechanism separates from the feeding belt. There is a problem that the contact pressure of the roller is increased and the torque applied to the separation roller is also large, so that the separation roller is rotated and cannot be separated. The present invention provides an automatic document feeder that solves this problem.

The first invention of the present invention is located above the document table on which the document bundle is placed, and feeds the document on the uppermost surface of the document bundle and separates and feeds the extracted documents one by one. In an automatic document feeder having a separating / feeding unit, a lower surface of the document taken out by the feeding unit is brought into contact between the feeding unit and the separating / feeding unit to restrict movement of the bottom document. A blocking member is provided.
As a result, since the document at the bottom of the document that has been taken out can be blocked in advance before the nip point, it is possible to reliably prevent the document from being double-fed.

  Moreover, what provided the guide member with the predetermined clearance above the blocking member can prevent double feeding more reliably. The blocking member is a plate-shaped blocking member having an inclined surface that rises in the document conveying direction and extends in the document width direction, and the guide member conveys the document outside both ends of the plate-shaped blocking member in the document width direction. The two rib-shaped guide members depending on the surface are compact, simple and inexpensive, and can eliminate jamming in the vicinity of the blocking member. The separating / feeding means includes a feeding belt held by a support roller and a separating roller in contact with the feeding belt, and a guide member attached to the feeding belt support portion has a more compact and rational configuration. When the guide member is a flange formed at both ends of the support roller of the feeding belt, the apparatus is simple, compact, and easy to manufacture.

  When the surface of the blocking member is made of a material having a large friction coefficient such as rubber, the blocking effect is increased. Further, when the leading end width of the plate-like blocking member becomes narrower in the document conveying direction, document jamming can be prevented.

  According to a second aspect of the present invention, there is provided a sheet feeding means for taking out the document on the uppermost surface of the document bundle positioned above the document table on which the document bundle is placed, a feeding belt held by a support roller, and a separation contacting the same. An automatic document feeder comprising a roller, and separating and feeding means for separating and feeding the taken documents one by one, and at both end portions of the support roller on the upstream side of document feeding of the feeding belt, A disc-shaped conveyance guide is provided. Thus, a conveyance path for preventing the movement of the superimposed document with a compact and simple structure can be formed, so that the document can be prevented from being double fed.

  According to a first aspect of the present invention, in an automatic document feeder having a sheet feeding unit and a separation feeding unit, a plurality of sheets are taken out by a blocking member provided between the sheet feeding unit and the separation feeding unit. The document at the bottom of the document can be blocked in front of the nip point in advance, and there is an effect that the document can be reliably prevented from being double fed.

  In addition, the structure in which the guide member is provided with a predetermined gap above the blocking member has an effect of more reliably preventing double feeding.

  According to a second aspect of the present invention, there is provided an automatic document conveying apparatus having a sheet feeding unit and a separation feeding unit including a separation roller. Since the conveyance guide is provided, it is possible to form a wedge-shaped conveyance path that prevents the movement of the superimposed document with a compact and simple structure, and there is an effect that it is possible to prevent the document from being double fed.

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

  FIGS. 1A and 1B are diagrams showing a separation feeding unit of an embodiment of an automatic document feeder according to the present invention. FIG. 1A is a side view schematically showing FIG. ) Is an XX arrow view of FIG. FIGS. 2A and 2B are diagrams showing a separation feeding unit of another embodiment of the automatic document feeder according to the present invention, and FIG. 2A is a schematic side view and FIG. 2 (b) is a partial top view of FIG. 2 (a).

  First, the embodiment shown in FIGS. 1A and 1B will be described. This automatic document feeder is substantially the same in configuration as the automatic document feeder of FIG. 3 described above except for the blocking member and the guide member according to the present invention. The description is omitted. In FIGS. 1A and 1B, reference numeral 21 denotes a guide path that forms a document conveyance path, and 22 denotes a device frame at the tip of the movable document table 3, and these conveyance paths and frames are This is the same as that shown in the conventional apparatus (see FIG. 3).

  Reference numeral 31 denotes a blocking member provided between the pickup roller 7 serving as a sheet feeding unit and the separation feeding unit including the feeding belt 9 and the separation roller 10, and a document bundle taken out at the leading end of the conveyance path 21. It is provided close to the tip of P. The blocking member 31 is a plate-shaped blocking member having an inclined surface 31a rising in the document conveying direction and extending in the document width direction, and its surface is made of a rubber material 31b. Reference numeral 32 denotes two rib-shaped guide members that hang down from the upper side toward the document conveying surface at positions outside both side ends of the plate-shaped blocking member 31 in the document width direction, that is, from the end of the plate-shaped blocking member 31. The plate-like blocking member 31 is attached with a predetermined gap and a gap through which about several originals pass. The tip of the rib-shaped guide member 32 is formed in a smooth curved shape (see FIG. 1A).

  If the guide member is attached with reference to FIG. 3, the guide member can be attached to the support shafts of the support rollers 9a and 9b that support the feeding belt 9, or the bracket 9c that supports the support shaft. . The specific structure is appropriately determined based on the shape and position of the blocking member, but is preferably attached to the support roller, particularly the upstream support roller portion, from the viewpoint of making the apparatus compact. As shown in FIG. 2B, the blocking member 31 has a shape in which the width of the front end portion (downstream side in the document conveying direction) becomes narrower in the document conveying direction.

  In the automatic document feeder having the above separating and feeding mechanism, as shown in FIG. 1A, even if a plurality of documents P are taken out from the pickup roller 7 (paper feeding means), the blocking member 31 is used. Since the movement is suppressed before reaching the nip point of the separation mechanism and the original is blocked, there is no trouble at the nip point as described above, and the double feeding of the original can be prevented. Further, since the document is sandwiched from above by the guide member 32, the document can be further effectively prevented. In the blocking member having a plate-like inclined surface, the original on the bottom of the original bundle can be effectively blocked with a simple member, and in the case where the surface is made of a rubber member, the original is more reliably secured by the frictional force. Can be prevented.

  Further, when the leading end width is narrowed and a rib-shaped guide member is disposed above the gap, the gap between the blocking member and the guide member is constant, and the document is not clogged, and the document can be blocked smoothly. (See FIG. 1 (b)).

  In the embodiment of FIGS. 1A and 1B, the guide member is a plate-like guide member having a rib-like or smooth edge-like tip, but the guide member is not limited to this. As in the embodiments shown in 2 (a) and 2 (b), the guide member 33 may be a flange 33 provided at both ends of the support roller 9b of the feeding belt 9. By providing the guide member 33 (flange) on the support roller 9a in this way, the apparatus becomes simple and compact, and the apparatus can be easily applied to a conventional model and inexpensive.

  Here, in the present invention, since many originals (original bundles) are not introduced into the nip point of the separation feeding mechanism, the movement of the original bundles is inhibited and prevented before the nip point, and the blocking member alone is used. Alternatively, the original is blocked by the cooperative action of the blocking member and the guide member. In FIG. 2A, when the blocking member having the inclined surface is removed, the guide path 21 and the guide member 33 (flange) are separated. A tapered conveying path having a wedge-like cross section is formed between them. Overlapping originals can be blocked in this tapered wedge-shaped conveyance path.

  The second invention can achieve the same effects as the first invention described above, and is simpler and more compact in terms of apparatus, and can be more easily applied to conventional apparatuses.

  In the above description, the automatic document conveying device applied to the copying machine has been described. However, the automatic document conveying device of the present invention is not limited to the copying machine, but is applied to image forming apparatuses such as facsimiles and scanner devices, printers, and the like. Applicable. Although the pickup roller has been mainly described as the paper feeding means, the paper feeding means is not limited to the roller type, and any paper feeding means such as other friction extraction means can be adopted, and the document separation and feeding means is also fed. Arbitrary separation / feeding means such as one using a feed roller is not limited to the one composed of a belt and a separation roller (reverse roller).

  The automatic document feeder of the present invention can be used not only for copying machines but also for image forming apparatuses such as facsimiles and scanners, printers, and the like.

1A and 1B are diagrams showing a separation and feeding unit of an embodiment of an automatic document feeder according to the present invention, FIG. 1A is a schematic side view, and FIG. 1B is a diagram of FIG. It is a XX arrow line view. FIGS. 2A and 2B are diagrams showing a separation and feeding unit of another embodiment of the automatic document feeder according to the present invention, FIG. 2A is a schematic side view, and FIG. 2B is FIG. FIG. FIG. 3 is a partial side sectional view schematically showing a paper feeding unit and a scanning unit, although the automatic document feeder 1 is mounted on a copying machine.

Explanation of symbols

7 Pickup roller (paper feeding means)
9 Feeding belt (separate feeding means)
9a, 9b Support roller 10 Separation roller (separation feeding means)
31 blocking member 31a inclined surface 31b rubber material 32 guide member (rib-shaped guide member)
33 Guide member (flange)

Claims (8)

  A sheet feeding unit that is located above the document table on which the document bundle is placed and takes out a document on the uppermost surface of the document bundle; and a separation feeding unit that separates and feeds the extracted document one by one. In the automatic document feeder, a blocking member is provided between the sheet feeding unit and the separation feeding unit so as to contact a lower surface of the document taken out by the sheet feeding unit and restrict movement of the document at the bottom. An automatic document feeder.   The automatic document feeder according to claim 1, wherein a guide member is provided above the blocking member with a predetermined gap.   The blocking member is a plate-shaped blocking member that has an inclined surface rising in the document conveying direction and extends in the document width direction, and the guide members are outside both side edges of the plate-shaped blocking member in the document width direction, The automatic document feeder according to claim 2, which is two rib-shaped guide members depending on the document feeding surface.   4. The automatic document feeder according to claim 2, wherein the separating and feeding means includes a feeding belt held by a supporting roller and a separating roller in contact with the feeding belt, and the guide member is attached to the feeding belt support portion. .   The automatic document feeder according to claim 4, wherein the guide member is a flange formed at both ends of the support roller of the feeding belt.   6. The automatic document feeder according to claim 1, wherein a surface of the blocking member is made of a material having a large friction coefficient such as rubber.   The automatic document conveying device according to claim 3, 4, 5, or 6, wherein the leading end width of the plate-shaped blocking member is narrowed toward the document conveying direction.   A document that is located above the document table on which the document bundle is placed, and that includes a sheet feeding means for taking out the document on the uppermost surface of the document bundle, a feeding belt held by a support roller, and a separation roller in contact with the feeding belt. In the automatic document conveying device having separation and feeding means for separating and feeding one sheet at a time, disk-shaped conveyance guides are provided at both end portions of the supporting roller on the document conveying upstream side of the feeding belt. An automatic document feeder characterized by that.

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