JP2001187652A - Sheet material feed mechanism in image processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet material feed mechanism in an image processing device surely preventing the overlapped feeding of sheet materials by optimizing the driving relation among a feed roller of the sheet material, a separation roller in its downstream, and a retard roller. SOLUTION: This sheet material feed mechanism is provided with the feed roller 3a picking up the paper sheets P stacked and mounted on a hopper 2b and feeding them to the image processing system and the roller pair of the separation roller 3b and the retard roller 3c for overlapped feeding prevention arranged in its downstream in an entrance of the image processing system. During the rotation driving of the feed roller 3a and after touching and reaching the tips of the paper sheets to the nip part of the roller pair, at least the separation roller 3b is rotation driven in the paper P feed direction and separates the topmost paper sheet P-1 from the paper sheet thereunder to feed it to the downstream side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus such as an image scanner for reading a document image or an image processing apparatus such as an image forming apparatus such as a copying machine, and more particularly to a hopper or tray type sheet material supply system. The present invention relates to a sheet material supply mechanism in an image processing apparatus capable of preventing double feeding of sheet materials.

[0002]

2. Description of the Related Art In printers, copiers and facsimile machines, a tray which is built in or detachable from the main body of the apparatus is provided, and a system in which paper is packed in this tray and automatically fed is widely used. I have. Also,
There are many types that use hoppers instead of trays.
Printers that have both a tray and a hopper as standard specifications are already known.

[0003] The tray is in the form of a flat container, and the tray corresponding to the paper size is incorporated in the apparatus.
Both the front end and the rear end of the stored sheet in the sheet feeding direction are loosely restrained by a member such as a clamper. On the other hand, most hoppers are externally mounted, and the paper is simply mounted on the hopper, and basically has a pair of guides that can adjust the position according to the width of the paper. Configuration. Such a hopper system is often used in an image scanner for reading a large number of documents having various sizes of documents and different paper qualities and thicknesses.

On the other hand, in an image forming or image reading apparatus such as a copying apparatus or an image scanner, it is very important to prevent double feeding of sheets supplied from a tray or a hopper. The occurrence of such a double feed causes a paper jam, and greatly reduces workability. Therefore, a separation roller and a retard roller are arranged immediately downstream of a tray or a hopper provided with a paper feed roller for picking up and feeding out the top one of the stacked sheets to prevent double feeding of sheets. Those that have been used are generally used. FIG. 5 is a schematic view of a conventional paper feed mechanism, and schematically shows a main part of a double feed prevention mechanism including a separation roller and a retard roller.

In FIG. 5A, a paper feed roller 52 is disposed on a stack of paper P mounted on a hopper 51, and a separation roller 53 and a retard roller 54 are provided downstream of the paper feed roller 52. Have. The separation roller 53 contacts the upper surface of the paper P supplied by the paper supply roller 52,
The retard roller 54 contacts the lower surface of the sheet P and nips the sheet P together with the separation roller 53. During the operation of the paper feed mechanism, the paper feed roller 52 and the separation roller 53 are respectively driven to rotate in the directions of the arrows in FIG. Also,
The retard roller 54 is mounted via a torque limiter (both not shown) on a main shaft that is driven to rotate in the direction of the arrow in the figure. It is driven to rotate in the direction of pushing back to the side. The retard roller 54 is elastically urged toward the separation roller 53, and the urging force can be adjusted according to the paper quality and thickness of the paper P.

In such a double feed prevention mechanism, the hopper 51
When only one sheet of paper P is fed and nipped between the separation roller 53 and the retard roller 54, the retard roller 54 receives the rotation torque of the separation roller 53, whereby the retard roller 54 It is driven and rotated in the transport direction. On the other hand, when two or more sheets of paper P are fed and nipped, the retard roller 54 keeps rotating in the direction of the arrow in the drawing due to the correlation between the built-in torque limiter and the biasing force on the separation roller 53. The lower sheet P is pushed back to the hopper 51 to prevent double feeding.

[0007]

The hopper 51 is urged toward the paper feed roller 52 by a spring (not shown) or the like, so that the top of the paper P stacked on the peripheral surface of the paper feed roller 52. The contact pressure with the object is set so as to be substantially constant. When the paper feed roller 52 is driven to rotate,
When only the top sheet P-1 is picked up, it is nipped between the separation roller 53 and the retard roller 54 as shown in FIG. You.

However, since the paper P loaded on the hopper 51 and the tray is used as it is drawn from the packing material for packing, the degree of adhesion between the papers P is considerably high, and the paper P on the side of the paper feed roller 52 of the hopper 51 is also used. The urging force acts on the sheet P. Therefore, when picking up by the paper feed roller 52, as shown in FIG. 5B, for example, three sheets P-1 to P-3 or more sheets are simultaneously separated by the separation roller 53 due to mutual contact friction. And may rush into the nip portion of the retard roller 54. On the other hand, the separation roller 53 and the retard roller 54 separate the sheets P-1 to P-3 and pass only the uppermost sheet P-1 to prevent double feeding. However, 3
When the degree of adhesion between the sheets P-1 to P-3 is strong, these sheets P-1 to P-3 pass through the nip between the separation roller 53 and the retard roller 54 as they are,
As a result, double feed occurs.

On the other hand, if only the sheet P-1 passes through the separation roller 53 and the retard roller 54 and is fed by the separation function, the double feeding is prevented. However, the leading ends of the second and third sheets P-2 and P-3 remain in the nip portion between the separation roller 53 and the retard roller 54. Therefore, after the sheet P-1 is completely fed,
In addition to the possibility of double feeding of sheets P-2 and P-3,
Since the paper feed start positions of −2 and P−3 are shifted, this may cause a paper jam.

The problem with such a conventional sheet supply mechanism is that the sheet supply roller 52 and the separation roller
One of the causes is that the third roller 3 and the retard roller 54 are driven to rotate in synchronization with each other.

Accordingly, the present invention provides a sheet material that can more reliably prevent double feed of a sheet material by optimizing a driving relationship between a sheet material supply roller and a separation roller and a retard roller downstream thereof. It is intended to provide a supply mechanism.

[0012]

According to the present invention, there is provided a hopper or tray on which sheet materials such as paper sheets are stacked and mounted, a supply roller for picking up the mounted sheet material and feeding it to an image processing system; A sheet material supply mechanism including a separation roller for preventing double feed and a roller pair of retard rollers disposed downstream and at the entrance of the image processing system, wherein the supply roller is driven to rotate, and After the leading edge of the sheet material reaches the nip portion of the roller pair, at least the separation roller of the roller pair is driven to rotate in the sheet material supply direction.

In such a configuration, even when a plurality of sheet materials are picked up from a hopper or a tray, when the leading ends of these sheet materials reach the nip portion between the separation roller and the retard roller, they are caught and the supply roller is stopped. By continuing rotation, the friction feed is applied to the top sheet material. Therefore, the top sheet material is bent upward and separated from the bottom sheet material, and the separation roller is driven to rotate at this timing, so that only the top sheet material moves downstream. It is conveyed, and double feed in the image processing system is prevented.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is a hopper or tray for laminating and mounting sheet materials such as paper, a supply roller for picking up the mounted sheet material and feeding it to an image processing system, and a supply roller. Of a sheet material provided with a separation roller for preventing double feed and a roller pair of a retard roller disposed downstream of the image processing system and a roller pair of a retard roller, when the supply roller is driven to rotate and the sheet material is rotated. A sheet material supply mechanism in the image processing apparatus, wherein at least the separation roller of the roller pair is driven to rotate in the sheet material supply direction after the leading end of the roller pair reaches the nip portion of the roller pair. Yes, even if a plurality of sheet materials are picked up by the supply roller, the difference between the rotation of the supply roller and the drive time between the separation roller and the retard roller is used. Has the effect that only the topmost sheet material can be supplied to the image processing system.

An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, an image scanner for reading an image from a document and creating an electronic file will be described as an example.

FIG. 1 is a schematic perspective view of an image scanner provided with a sheet material supply mechanism according to the present invention.

As shown in the figure, the apparatus comprises a main body 1 having an image scanner, a reading section of an optical system, and a paper transport path, and an automatic paper feeder 2 as paper feed means. The main body 1 has an operation panel 1a on the front and a controller (not shown) for controlling all devices inside. On the upper surface of the main body 1, there is provided a collection tray 1b for receiving the paper fed from the automatic paper feeder 2 and having finished the image reading by the reading unit.

The automatic paper feeder 2 has a main body 1 on which paper is loaded.
It has a hopper function of feeding the paper to a transport path inside and a function of preventing double feed of paper. FIG. 2 is a schematic diagram from the hopper of the automatic paper feeder to the paper transport path and the collection tray.

The automatic paper feeder 2 has a hopper 2b incorporated in a housing 2a so as to be rotatable up and down.
b is driven by being connected to a motor (not shown), and when feeding the paper, the paper P is rotationally urged upward until the paper P comes into contact with the supply roller 3a as shown in FIG. The upper surface of the hopper 2b is provided with a guide 2d that can be manually moved in a pair of frontage directions (left and right directions as viewed from the front) for guiding the width direction of the sheet P.

A pair of a separation roller 3b and a retard roller 3c for preventing double feeding of the paper P is disposed downstream of the supply roller 3a that picks up and feeds the paper P one by one on the hopper 2b. Collection tray 1 from roller pair
A conveyance path for the sheet P is formed between the sheet P and the sheet B. A plurality of transport rollers 3d for nipping and transporting the paper P are disposed in the transport path of the paper P, and a first scanning sensor 3e for reading an original image on the upper surface of the paper P is provided in the middle.
And a second scanning sensor 3f for reading a document image on the lower surface. Then, one sheet of paper P picked up from the hopper 2b by the supply roller 3a is read by the first and second scanning sensors 3e and 3f while passing through the transport path, and is then transferred to the collection tray 1b. The paper is ejected.

FIG. 3 is a detailed view of a main part of the sheet supply mechanism of the present invention.

The supply roller 3a is shown in FIGS. 3 (a) and 3 (b).
As shown in (1), a constant pressing force is always applied to the top sheet P-1 of the stacked sheets P by the upward urging force of the hopper 2b. The paper P-1 is picked up and fed by the friction between the supply roller 3a and the paper P-1 due to the pressing force. When the separation roller 3b is driven, it rotates in the same direction as the supply roller 3a, but its activation timing is delayed with respect to the start of rotation of the supply roller 3a, and the uppermost sheet P of the multi-feed sheet is rotated. When the paper feeding is completed, the startup is restarted.

As described in the prior art of FIG. 5, the retard roller 3c is connected via a torque limiter 3c-2 to a main shaft 3c-1 which is driven to rotate clockwise in FIG. The main shaft 3c-1 is supported by a support mechanism (not shown) that elastically urges the retard roller 3c in the direction of the separation roller 3b, and the double feed of the paper P is prevented by the urging force and the function of the torque limiter 3c-2. I do.
Such a configuration of the retard roller 3c having the built-in torque limiter 3c-2 is well known in the field of a sheet feeding mechanism in an image forming apparatus.

Here, in the present invention, when the paper P is fed, the rotation of the supply roller 3a is started, but the separation roller 3b and the retard roller 3c are driven to rotate later than the start time. Control. That is, as shown in FIG. 3A, the supply roller 3a rotates and the paper P
Even after picking up -1, the separation roller 3b and the retard roller 3c remain stopped. Then, as shown in FIG. 4B, the separation roller 3b and the retard roller 3c are retarded when the separation roller 3b and the retard roller 3c nip the leading edge of the sheet P-1 or at a timing that is much shorter than this. Activate the roller 3c. As a result, one sheet of paper P-1 is nipped between the separation roller 3b and the retard roller 3c, and at the same time, the retard roller 3c rotates in the direction opposite to the rotation direction of the main shaft 3c-1, that is, in the paper feeding direction. P-1 is immediately sent out to the transport path.

In the above configuration, when the operation button 1a-1 on the operation panel 1a is turned on, the supply roller 3a starts to rotate in the direction of the arrow in FIG. 2, and the separation roller 3b and the retard roller 3c operate at the timing shown in FIG. , And the transport roller 3d on the downstream side also starts rotating at the same timing. As a result, the uppermost sheet of the paper P loaded on the hopper 2b is picked up by the supply roller 3a, and is supplied to the transport path through the separation roller 3b and the retard roller 3c as shown in FIG. Is done.

When the paper P is picked up by the supply roller 3a, if the degree of close contact between the papers P is strong, as shown in FIG. And it advances to the retard roller 3c side. In the conventional structure, since the separation roller 3b and the retard roller 3c are always rotating at the same time as the supply roller 3a, a plurality of sheets penetrate between the separation roller 3b and the retard roller 3c, and double feed occurs. I do. On the other hand, in the present invention, the leading end of the paper P is later than the time at which the supply roller 3a starts to be driven to rotate.
The separation roller 3b and the retard roller 3c are driven at the time when the nip point is contacted between the separation roller 3b and the retard roller 3c.

FIG. 4 is a detailed view of a main part of the sheet supply mechanism of the present invention.

As shown in FIG. 4, for example, three sheets P
When -1 to P-3 advance toward the separation roller 3b and the retard roller 3c in the double feeding state, the leading ends of these sheets P-1 to P-3 are stopped by the separation roller 3b and the retard roller 3c. The abutment on the nip or the peripheral surface prevents the advance. On the other hand, since the supply roller 3a keeps rotating, the uppermost sheet P-1 in contact with its peripheral surface tries to advance while leaving the lower sheets P-2 and P-3 as they are. Therefore, as shown in FIG.
Is deformed so as to be wrinkled upward, and the paper P
-2 to form an air space. And
When the separation roller 3b and the retard roller 3c are rotationally driven with a time difference such that the sheet P-1 can be bent and deformed, an air layer is formed between the sheet P-2 and the sheet P-2. Only the top sheet P-1, which has been released from the restraint due to the friction between the roller P-2 and the roller P-2, is likely to be nipped by the separation roller 3b and the retard roller 3c. By this nip, the sheet P-1 is fed as shown in FIG. 9C, and the sheet P-1 is fed so that the upward bending deformation is gradually restored to the original flat shape.

As described above, even if the sheet P is fed double to the separation roller 3b and the retard roller 3c, the sheet P-1 is kept on the lower side during the continuation of the rotation of the supply roller 3a and the stop period of the separation roller 3b. The sheet P-2 is separated from the sheets P-2 and P-3, and only the sheet P-1 can be sent to the downstream conveyance path. Therefore, even if the paper P is double-fed at the pickup stage on the hopper 2b side, only the uppermost paper P-1 is fed by the separation roller 3b and the retard roller 3c, and the conveyance including the reading unit is performed. Double feeding of the paper P on the road side is prevented.

Further, the sheet P-1 is transferred to the first-stage conveying roller 3.
d, the supply roller 3a, the separation roller 3b, and the retard roller 3c temporarily stop rotating, and the supply roller 3a is also supplied when the next sheet P-2 is supplied.
Roller 3b and retard roller 3c after the start of
Is started. Also in this case, by feeding the sheet P-2 until the sheet P-2 comes into contact with the nip portion between the separation roller 3b and the retard roller 3c, the sheet P-2 bends similarly to the sheet P-3 so as to expand upward. Deform. Therefore, as in the case of feeding the sheet P-1, the sheet P-3 can be left and only the sheet P-2 thereon can be fed. And after that,
The supply roller 3a continues to rotate, and the separation roller 3b and the retard roller 3c are driven to rotate with a time lag, so that when the paper P is double-fed from the hopper 2b, the paper P Paper can be fed.

In the above description, the retard roller 3
Although c is driven to rotate at the same time as the separation roller 3b, any configuration may be used as long as only the separation roller 3b is driven to rotate. In this case, the retard roller 3c may be capable of performing the function of preventing double feed by the torque limiter 3c-2.

[0032]

According to the present invention, even if a plurality of sheet materials such as sheets loaded on a hopper or a tray are picked up by a supply roller, the time difference of the rotational drive between the downstream separation roller and the retard roller is utilized. The double feeding of the sheet material can be prevented by the separation roller portion, and the sheet material does not enter the image processing system in the double feeding state. Therefore, image formation and image reading can be performed without any trouble, and only the control for the time difference between the driving of the supply roller and the separation roller in the existing apparatus needs to be added, so that the apparatus is not complicated.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of an image scanner provided with a sheet material supply mechanism of the present invention.

FIG. 2 is a schematic view of a hopper of an automatic paper feeder, a paper conveyance path, and a collection tray.

FIG. 3 is a detailed view of a main part of a sheet material supply mechanism of the present invention.

FIG. 4 is a detailed view of a main part of a sheet material supply mechanism of the present invention.

FIG. 5 is a schematic diagram of a conventional paper feed mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 1a Operation panel 1a-1 Operation button 1b Collection tray 2 Automatic paper feeder 2a Housing 2b Hopper 2d Guide 3a Supply roller 3b Separation roller 3c Retard roller 3c-1 Main shaft 3c-2 Torque limiter 3d Transport roller 3e First scan Sensor 3f Second scanning sensor P, P-1, P-2, P-3 Paper

Claims (1)

[Claims] A hopper or tray for stacking and loading sheet materials such as paper, a supply roller for picking up the loaded sheet material and feeding it to an image processing system; and a downstream of the supply roller and the image processing system. A sheet feeding mechanism including a separation roller for preventing double feed and a roller pair of a retard roller disposed at an entrance of the sheet material, wherein the rotation of the supply roller is performed and the leading end of the sheet material is the roller pair. A sheet feeding mechanism in the image processing apparatus, wherein at least the separation roller of the pair of rollers is driven to rotate in the sheet feeding direction after reaching the nip portion.