JP3782474B2 - Document feeder for image forming apparatus - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a copying machine, a facsimile, in which a turn portion for discharging an exposed document is formed in a document transport path, and a document reversing path for exposing both sides of the document is switchable on the turn portion. The present invention relates to a document feeder attached to an image forming apparatus such as a printer.
[0002]
[Prior art]
In recent years, double-sided originals are increasing due to multifunctional functions of copying machines and the like, and saving of paper resources. For this reason, there are many opportunities to obtain double-sided copies from double-sided originals. In view of this, there has already been proposed an apparatus (hereinafter referred to as ARDF) having a reversing function capable of automatically exposing both sides of a double-sided document so that a double-sided copy can be easily obtained from a double-sided document in a conventional document feeder. In the ARDF, the document is generally reversed and discharged after being turned by a turn portion provided with a driving reverse roller. Therefore, the reverse roller takes into consideration the burden on the document and the load on the drive system. The diameter of the reversing roller is preferably as large as possible. On the other hand, image forming apparatuses such as copiers are increasingly required to be miniaturized every year. For this reason, it is desired to reduce the diameter of the reverse roller, which is the ARDF turn diameter.
[0003]
[Problems to be solved by the invention]
However, in order to reduce the ARDF turn diameter, the problem of the burden on the document and the load on the drive system must be cleared. In particular, since ARDF transports a wide variety of originals, it is necessary to reliably turn even stiff originals. In addition, as the speed of copying machines and the like increases, it is necessary to secure a driving force that allows the speed of the turn part. Don't be. Therefore, in the case of the conventional ARDF, when the diameter of the reversing roller or the like is simply reduced, not only the problem of the burden on the document cannot be cleared, but also the document conveying force necessary for the turn portion cannot be obtained.
[0004]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional circumstances, and an object of the present invention is to provide a document feeding device that can reliably obtain a document conveying force required for a turn portion even when the diameter of the turn portion is reduced.
[0005]
[Means for Solving the Problems]
According to the present invention, in order to achieve the above object, a turn part for discharging an exposed document is formed in the document transport path, and a document reversing path for exposing both sides of the document can be switched in the turn part. In the document feeding device of the image forming apparatus formed in the above, the turn portion is composed of a rotatable guide roller having a turn diameter and a document guide member provided on the outer peripheral side of the guide roller. A document conveying mechanism that applies a conveying force to the document at each of the entrance and the exit of the document reversing path, and rotates the guide roller by the document conveying resistance on the inner peripheral side of the turn portion to convey the document while inverting it. Means is provided .
[0006]
Furthermore, in order to achieve the above object, the present invention provides a common drive rotator and an inlet side on which the document transport means provided at the entrance of the turn section and the exit of the document reversing path are rotated by the drive rotator. It is characterized by comprising a driven rotator and an outlet side driven rotator.
[0007]
[Action]
According to the above configuration, the turn part is configured by the inner and outer document guide members, and the inner document guide member is rotatable in the circumferential direction of the turn part. Since the conveyance force is applied before and the conveyance force is also applied at the reverse exit, the document is pulled out from the exit of the turn portion, and the document conveyance of the turn portion can be stabilized in combination with the conveyance force at the entrance.
[0008]
【Example】
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0009]
FIG. 1 is an overall schematic diagram showing an ARDF according to the present invention. In FIG. 1, an ARDF denoted by reference numeral 1 is attached to a copier body 2 so as to be openable and closable on a contact glass 3 via a hinge (not shown). The ARDF 1 includes a conveyance belt mechanism 4 having a conveyance belt having a size covering the contact glass 3, a document feeding mechanism 5 disposed on one side of the conveyance belt mechanism 4, in this example, the left side of the drawing, And a reversing / discharging mechanism 6 disposed on the right side of the drawing, which is the other side of the conveying belt mechanism 4. A document table 7 for setting a document to be fed is provided at the center upper position of the ARDF 1, and a document discharge unit 8 for stacking the discharged document is disposed below the document table 7. Since the transport belt mechanism 4 and the document feeding mechanism 5 are not the gist of the present invention, detailed description thereof will be omitted.
[0010]
As shown in FIGS. 1 and 2, the ARDF 1 reversal / discharge mechanism 6 is composed of a relatively large-diameter reversal driving roller 10 and a small-diameter inlet driven roller 11 as document conveying means at the entrance. A reversing entrance driving unit is provided, and a turn part composed of an outer peripheral side document guide member 12 and an inner peripheral side guide roller 13 is provided following the entrance driving unit. As shown in FIG. 3, the guide roller 13 has a plurality of roller-shaped ribs 15 attached to an axis 14 parallel to the axis of the reverse driving roller 10. In this case, the guide roller 13 may be configured such that the shaft 14 and the roller-shaped rib 15 are separate members, and the roller-shaped rib 15 may be rotatably attached to the shaft 14. Those formed integrally with the roller-shaped rib 15 are preferable. If the guide roller 13 is molded with a mold, there is no fear of a large load, so the guide roller 13 can be attached to the side plate 16 without a bearing. Further, since the guide roller 13 is composed of a relatively narrow roller-shaped rib 15, the conveyance resistance is less than that formed by a surface, and smooth document conveyance is obtained.
[0011]
The reversing / ejecting mechanism 6 is provided with a switching claw 17 following the turn portion having the above-described configuration. When the switching claw 17 is switched to the position of the chain line in FIG. 18 is discharged to the document discharge section 8. When the switching claw 17 is switched to the position indicated by the solid line in FIG. 2, the document is reversed so as to go around the guide roller 13 substantially once, and is constituted by the reversing driving roller 10 and the outlet driven roller 19 as document conveying means. Returned to the conveyor belt mechanism 4 again through the reversing outlet driving unit.
[0012]
When the ARDF 1 having such a configuration is operated, in the case of single-sided copying, after the document fed by the document feeding mechanism 5 is stopped at a predetermined position on the contact glass 3 by the conveyor belt mechanism 4 and exposed, The document is conveyed to the reversing / discharging mechanism 6, and the document is first given a sufficient conveying force to push the turn portion by the reversing driving roller 10 and the inlet driven roller 11. That is, the reverse driving roller 10 and the entrance driven roller 11 do not reverse the small-diameter turn portion with respect to the original, but apply the conveying force in a state where the original document is near the flat surface. Is given. Then, the original advances along the conveyance path in the reversal / discharge mechanism 6 and is turned by the guide roller 13. At this time, the switching claw 17 is switched to the position of the chain line. Is discharged. Therefore, if the document is provided with a conveyance force sufficient to advance the turn portion by the reverse driving roller 10 and the inlet driven roller 11 and then the leading edge of the document is held by the discharge roller 18, the leading edge side and the trailing edge of the document. Sufficient conveyance force is provided to pass through even the turn portion having a small diameter by the conveyance force at the end side.
[0013]
In the case of duplex copying, the document fed by the document feeding mechanism 5 is first transported as it is on the contact glass 3 by the transport belt mechanism 4 and guided to the transport path in the reversing / discharging mechanism 6 for switching. When the claw 17 is switched to the position of the solid line, it is turned along the guide roller 13, and when the document is close to a flat surface, a conveying force is given by the reverse driving roller 10 and the reverse exit driven roller 19. . Then, the original is discharged from the reverse path, and is conveyed to a predetermined position on the conveying belt mechanism 4 contact glass 3 which rotates in reverse at the same timing, and the back surface is exposed. After that, the image is reversed again by the reversing / discharging mechanism 6 and the surface is exposed, and is discharged to the document discharge section 31 through the reversing / discharging mechanism 6 as in the case of single-sided copying.
[0014]
Thus, the document is turned by the reversing / discharging mechanism 6, and the guide roller 13 is turned almost one turn particularly at both sides, but the document is turned by the reversing driving roller 10 and the inlet driven roller 11 at the entrance of the reversing / discharging mechanism 6. Since the conveying force is applied and the conveying force is applied by the reversing driving roller 10 and the reversing outlet driven roller 19 at the outlet of the reversing / discharging mechanism 6, the conveying force necessary for the turn can be obtained with certainty. That is, if the document is reversed by the reversal driving roller 10 and the inlet driven roller 11 to give a sufficient conveying force to advance the turn portion, the front end of the document is held by the reversal driving roller 10 and the reversing outlet driven roller 19. Since the action of pulling out the document from the exit of the turn portion is given, the conveyance force necessary for the turn can be obtained with certainty. And the guide roller 13 of a turn part can be freely rotated, and the tolerance which can make a turn diameter small also becomes large.
[0015]
Although the document conveying means on the inlet side and the outlet side of the reversing / ejecting mechanism 6 may be driven separately, by using the reverse driving roller 10 on the inlet side and the outlet side as in this embodiment, This is extremely advantageous in terms of space saving and cost saving.
[0016]
【The invention's effect】
According to the configuration of the first aspect, the turn portion is composed of a rotatable guide roller having a turn diameter and a document guide member provided on the outer peripheral side of the guide roller. Document conveying means is provided for conveying the document while inverting the document by applying a conveying force to the document at the exit of the reversing path and rotating the guide roller by the document conveying resistance on the inner peripheral side of the turn portion. Since the conveyance force is applied before the application of the document conveyance force at the turn part, and the conveyance force is also applied at the reversing exit, the document is pulled out from the exit of the turn part and coupled with the conveyance force at the entrance to convey the document at the turn part. Can be stabilized.
[0017]
According to the configuration of the second aspect, the document conveying means provided respectively at the entrance of the turn portion and the exit of the document reversing path has a common driving rotator, and an inlet-side driven rotator and an outlet that are driven to rotate by the driving rotator. Since it is constituted by the side driven rotator, the single conveying rotator can share the inlet and outlet document conveying means, and the structure can be provided at a low cost.
[Brief description of the drawings]
FIG. 1 is an overall schematic diagram showing an ARDF according to the present invention.
FIG. 2 is an enlarged view of the ARDF reversal / discharge mechanism.
FIG. 3 is a perspective view of the reversing / discharging mechanism.
[Explanation of symbols]
1 ARDF
6 Reverse / discharge mechanism 10 Reverse drive roller 11 Reverse entrance driven roller 13 Guide roller 17 Switching claw 19 Reverse exit driven roller

Claims (2)

In a document feeding device of an image forming apparatus, a turn part for discharging an exposed document is formed in a document transport path, and a document reversing path for exposing both sides of the document is switchable on the turn part. ,
The turn portion is composed of a rotatable guide roller having a turn diameter and a document guide member provided on the outer periphery of the guide roller, and the document is respectively provided at the entrance of the turn portion and the exit of the document reversing path. A document feeding means is provided, wherein a document feeding means is provided on the inner periphery side of the turn portion to rotate the guide roller by the document feeding resistance and to convey the document while inverting the document. apparatus. 2. The document feeding device of the image forming apparatus according to claim 1, wherein the document conveying means provided respectively at the entrance of the turn portion and the exit of the document reversing path is rotated by a common drive rotator and the drive rotator. An original feeding apparatus comprising an inlet-side driven rotator and an outlet-side driven rotator.

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