JPH0640585A - Document feeding device - Google Patents

Abstract

(57) [Abstract] [Purpose] A pair of separation rollers and a feed roller is provided on the downstream side of the document feeding table, and a bundle of documents is fixed on the document feeding table with its tip aligned with the separation roller. The document is brought into contact with a stopper, the leading edge of the original stack is pressed by an elastic thin plate extending from the upper side to the lower side, is inserted into the pressure contact portion of the separation roller and the feed roller, and is stacked by the document feeder that separates and feeds the sheets one by one. The purpose is to reliably separate and feed the originals one by one regardless of the number of originals, curl and folding of the originals. The elastic thin plate 17 is displaceable in the original feeding direction, and the lower end of the originals of the original stack 2 is pressed by the elastic plate 17 regardless of the number of originals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document feeding device for a document reading device.

[0002]

2. Description of the Related Art In a document reading device of an image forming apparatus such as a scanner, an electrophotographic copying machine, a facsimile, a printer, etc., a reading unit for separating one by one from a plurality of document bundles placed on a document feeding table. As a document feeding device for feeding to
As illustrated in FIG. 2, a pickup roller 4 that is provided on the lower side of the downstream side end portion of the document 2 in the transport direction of the document feed table 1 and that is rotatable in the transport direction, presses the lower end front end portion of the document stack 2 against the pickup roller 4. The pressure plate 3, a feed roller 6 provided on the downstream side of the document conveyance path and below the document conveyance path, rotatable in the conveyance direction, and pressed against the feed roller 6 through the document conveyance path, and axially supported by a fixed shaft. It is composed of a separating roller 5 which is pressed against a friction disk supported by the other end of a coil spring having one end fixed, and a stack of documents 2 pressed from above by a pickup roller 4 rotated by a document feeding signal is sent out from the bottom and sent out. The original document is pressed into contact with the feed roller 6 and both ends thereof are elastically supported. One having a structure which is adapted fed to the reading unit are well known.

FIG. 1 shows an example of a heat-sensitive facsimile, in which an original is provided with a pair of conveying rollers 7 and 8 on the upstream side and the downstream side of a contact glass 21 forming a reading portion.
The original is contacted with the contact glass 2 by the pair of conveying rollers.
The light source 9 slides on the upper surface of the sheet 1 and is conveyed at a constant speed.
The original is read by illuminating the slit with a slit, guiding the reflected light through a mirror 10 to an image forming system composed of an image forming lens and a CCD, and forming an image on the CCD by the image forming lens.

On the other hand, recording is carried out by passing a thermal paper pulled out from the roll 12 between the thermal head 13 which operates by an information signal sent from the other party of communication and the platen roller 14 which presses against the thermal head 13. Then, the paper is cut by the cutter 15 and discharged by the paper discharge roller 16. An operation panel 20 for operating the facsimile is provided on the upper surface of the cover of the reading device.

By the way, in the document feeding apparatus having the above structure,
In order to make it easy for the original to enter the pressure contact portion between the feed roller and the separation roller even when the original is curled upward or the front end is bent upward, for example, as shown in FIG. 2 in Japanese Utility Model Laid-Open No. 3-80044. Roller-shaped stoppers 19 are provided on both sides of a fixed shaft separating roller that pivotally supports the separating roller 5, and a leading edge of a document is provided obliquely extending forward and downward at a position not interfering with the stopper 19 and the separating roller 5 immediately upstream thereof. It has been proposed to provide a thin plate 17 such as a polyethylene terephthalate (trade name: Mylar) plate that presses against with the base end fixed to the machine frame.

When the number of originals placed on the original feed table is large, as shown in FIG. 4, the tips of a large number of originals are brought into contact with the peripheral surface of the stopper 19 and the curvature of the stopper 19 is increased. As a result, the document is stuck between the feed roller 6 and the separation roller 5 to prevent double feeding. However, in this case, since the base end position of the elastic thin plate 17 is constant, the elastic thin plate 17 is pushed upward by the front end of the stacked document stack, so that the front end of the elastic thin plate 17 does not reach the front end of the lower sheet of the document stack. If the original is curled upward or the tip is bent upward, the original is fed by the feed roller 6 and the separation roller 5 due to the contact angle of the original with the separation roller 5.
Jam was frequently generated without being inserted into the pressure contact part with.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the document feeding apparatus having the above-described structure, and the occurrence of a jam is not affected by the number of documents, the curled state of the documents, and the folding condition of the leading edge. It is an object of the present invention to provide a document feeding device that solves the above problem with a simple configuration.

[0008]

The present invention is characterized in that, in the document feeding apparatus having the above-mentioned structure, the document pressing elastic thin plate can be displaced within a predetermined range in the document conveying direction.

[0009]

As described above, the elastic thin plate for pressing the original can be displaced in the original feeding direction. Therefore, when the number of stacked originals is large, the elastic thin plate is displaced forward in the original conveying direction so that the elastic thin plate is bundled. When the number of originals stacked is small, the elastic thin plate is slid rearward in the original conveying direction so that the elastic thin plate can be easily abutted against the front edge of the lower sheet of paper, and the elastic thin plate can be curled or folded. By holding down the leading edge of the paper and pressing it against the stopper, the function of the elastic thin plate can be maintained, and the document separation performance is ensured.

Problems other than the above and means for solving the problems will be clarified by the description of the embodiments described in detail below with reference to the drawings.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 3 is a diagram showing a structure in the vicinity of a document holding elastic thin plate of an embodiment in which the present invention is applied to the document feeding apparatus described in FIGS. 1 and 2. In this embodiment, the elastic thin plate 17
Can be displaced to three positions b, a, and c in order from the front in the document transport direction.

The elastic thin plate 17 is normally set to the position a, and when the number of originals is large, the elastic thin plate 17 is moved to the position b, and as shown in FIG. Even when the document comes into contact with, the elastic thin plate 17 is pushed down to the leading end of the lower document. By doing so, even if the front end of the document is desired to be curled upward, the front end is not caught by the separation roller, and when the original is sent out in order from the lower order by the pressure plate 3 and the pickup roller 4, the feed roller 6 Then, they are smoothly inserted into the pressure contact portion of the separation roller 5, separated, and fed one by one. When the number of originals is small, for example, 1 to 5, the elastic thin plate 17 is used.
By shifting to the position of C shown by the broken line in FIG.
The tip of the elastic thin plate 17 comes to a position where the tip of the original is pressed, and even if the original 2 is curled up or the front of the original is bent upward, the front of the original is pressed by the elastic thin plate and the original It is prevented that the leading end is caught by the stopper 19 or the separation roller 5 and a jam occurs.

As described above, as a means for making the elastic thin plate 17 movable in the document conveying direction, as shown in FIG. 6, the sliding ends 17a extending the base ends of the elastic thin plates 17 on both sides parallel to the document conveying direction. It is provided in a forked shape at the front end of the
As shown in FIG. 7, elongated holes 23 that engage with guide pins 22 provided on the machine frame are provided, and on both sides thereof, front ends are integrally connected to the sliding portion main body to form a plastic hinge, and thereafter, the main body 17a is formed. A rod-shaped member 17b that is loosened is provided, and one engaging protrusion 17c is integrally formed on the outside of 17b, and the engaging protrusion 17c is formed on the apparatus main body frame.
A member 24 having, for example, three recesses 24a, 24b, and 24c that engage with each other is provided, and the elasticity of the connecting portion of the rod-shaped member 17b is used to make the engagement projection 17a and the recesses 24a, 24b
It is simple and reliable to releasably engage any one of the 24c.

Further, if the elastic thin plate 17 is placed at the position C in FIG.
When a large number of originals are placed with the original set, the bundle of originals is blocked by the elastic thin plate and the leading edge of the originals does not reach the pressure contact portion between the feed roller 6 and the separation roller 5 and the feeding failure occurs. Resulting in. To solve this problem, as shown in FIG. 8, a rigid member 17 '(for example, made of hard plastic) that engages with the upper end of the front end of the document stack is fixed to the sliding portion 17a continuous to the base end of the elastic thin plate 17. When the original stack 2 is set and the number of the set originals 2 is equal to or larger than a predetermined number, the hard member 17 ′ is pushed by the upper part of the front end of the original stack to move forward together with the elastic thin plate 17. By doing so, the setting state of the elastic thin plate can be automatically changed according to the number of originals. If the elastic thin plate member 17 is biased rearward by a spring so that the projection 17c can be engaged with the recess 24 from the front or the rear, the elastic thin plate 17 can be automatically moved rearward. Becomes

[0016]

As described above, according to the present invention, the separation performance of the document feeder is improved. If the elastic thin plate can be moved stepwise as described in claim 2, it is easy to manufacture and it is effective in cost reduction. Further, by providing the elastic thin piece itself with the function of holding and releasing the elastic thin piece at a predetermined position as described in claim 3, the number of parts is reduced, the structure is simplified, and the cost is reduced. According to the structure of claim 4,
The elastic thin piece can be automatically displaced to a position suitable for the number of documents loaded.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an overall schematic configuration of an example of an image forming apparatus including a document feeding apparatus to which the present invention is applied.

FIG. 2 is a perspective view showing a document pressing elastic thin piece and a stopper provided in the document feeding device.

FIG. 3 is an explanatory view for explaining a displaced state of an original pressing elastic thin piece according to the present invention.

FIG. 4 is an explanatory diagram illustrating an operation of the present invention.

FIG. 5 is an explanatory diagram illustrating an operation of the present invention.

FIG. 6 is a plan view showing an example of the shape of an elastic thin piece of the present invention.

FIG. 7 is a perspective view showing an engaged state of the elastic thin piece with a sliding guide pin and a positioning engaging projection.

FIG. 8 is a perspective view showing a means for automatically displacing the elastic thin piece to a position according to the number of documents.

[Explanation of symbols]

 1 Document Feeding Table 2 Document 3 Pressing Plate 4 Pickup Roller 5 Separation Roller 6 Feed Roller 17 Document Holding Elastic Thin Plate 17 'Hard Member 19 Stopper

Claims (4)

[Claims] 1. A pickup roller which is provided on the lower side of a downstream side end of the document feeding table in the document conveying direction and is rotatable in the conveying direction, a pressure plate for pressing the lower surface of the document stack against the pickup roller, and a downstream side thereof. A feed roller which is provided below the document transport path and rotatable in the transport direction; a separation roller which is pressed against the document transport path through the document transport path and is rotatably supported by a torsion spring on a fixed shaft; A roller-shaped stopper fixedly provided on a fixed shaft that axially supports the separation roller outside the separation roller, and extends obliquely forward and downward at a position that does not axially interfere with the stopper and the separation roller, In an original feeding device that has an original pressing elastic thin plate that presses the front edge of the original whose tip contacts the separation roller, and separates and feeds the originals one by one, the original pressing elastic thin plate conveys the original. Can be displaced within a predetermined range in any direction Document feeder, characterized in that it. 2. The document feeding apparatus according to claim 1, wherein the relative position of the elastic plate for pressing the document is movable to a predetermined position in multiple steps in a relative position. 3. The document feeding apparatus according to claim 2, wherein the document pressing elastic thin plate is held at the above-mentioned multi-step positions, and the document pressing thin plate itself has a stopper function capable of being released. apparatus. 4. The original pressing elastic thin plate is optimized by fixing a hard member to the original pressing elastic thin plate, and when a large number of originals are set thereunder, the hard member is pressed by the front end portion of the original stack. The document feeding apparatus according to claim 1, wherein the document feeding apparatus is configured to move to a position.