JP2002002993A - Supply mechanism for sheet material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a supply mechanism for a sheet material capable of surely preventing double feed according to the quality of the sheet material such as paper by varying set torque of a retard roller. SOLUTION: An output shaft 11 of a retard motor and the retard roller 5 are connected with gears 12a, 12b, 12c; a rotating shaft 13; gears 14a, 14b with one way clutch; gears 15a, 15b, 15c, 16a, 16b; rotating shafts 17a, 17b; and torque limiters 18a, 18b, and the rotating shaft 13 and the gears 14a, 14b are connected or disconnected according to the rotating direction of the rotating shaft 13 with the gears 14a, 14b with one way clutch to shift the torque limiters 18a, 18b acting on the retard roller 5.

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. The present invention relates to a material supply mechanism.

[0002]

2. Description of the Related Art An image reading apparatus such as an image scanner is provided with a paper feeding device for feeding a sheet set on a hopper to a line. This paper feeder picks up and feeds out stacked papers one by one from the top, and most of the paper feeders have a double feed prevention mechanism in which two or more sheets are fed out by friction between overlapping sheets. is there. Japanese Patent Application Laid-Open No. Hei 4-28655 discloses a paper feeder having such a double feed prevention mechanism.
No. 8 has been disclosed.

FIG. 7 is a schematic view showing a conventional paper feeder, and the one disclosed in the above publication has almost the same configuration.

In FIG. 7, a hopper 5 for mounting and setting paper P such as an original to be read or various documents is set.
1 is disposed at the base end of the reading line, and above the hopper 51, a supply roller 52 for picking up and feeding out the uppermost sheet P is disposed. The hopper 51 is urged toward the supply roller 52 by a spring 51a, and presses the sheet P against the supply roller 52 so that only the uppermost sheet P can be fed out by friction with its peripheral surface. Also, paper P
Even if the thickness of the laminated sheet changes, the pressing force against the supply roller 52 is kept substantially constant by the spring 51a.

In the line on the output side of the hopper 51, for example, three-stage conveying rollers 53, 54 and 55 for feeding the paper P to the image reading position are arranged, and the paper P fed from the hopper 51 is nipped. And transport it downstream while pulling it out. A separation roller 56 and a retard roller 57 are provided between the hopper 51 and the first-stage transport roller 53 as a mechanism for preventing double feeding of the paper P.

The prevention of double feeding by the separation roller 56 and the retard roller 57 is widely known in the field of an image reading apparatus, a copying apparatus and the like.
Is a motor in which a torque limiter 57b is interposed around a main shaft 57a rotated in a direction indicated by an arrow in the drawing by a drive motor (not shown). The main shaft 57a of the retard roller 57 is connected to a drive motor (not shown) shared with the separation roller 56, and is attached upward in the figure by a spring for setting a nip force with the separation roller 56. It is being rushed. Such a torque limiter 57
When one sheet P is fed from the supply roller 52, the retard roller 57 receives the rotation torque of the separation roller 56 and rotates in the transport direction of the sheet P. Then, when two or more sheets P are multi-fed and nipped, the retard roller 57 rotates in the direction of the arrow to push the double-fed lower sheet P back to the hopper 51 side.

[0007]

However, as the conventional torque limiter 57b of the retard roller 57, a fixed torque value is used, and the operating torque of the torque limiter 57b cannot be changed. On the other hand, in an image scanner or the like used for reading various types of paper P, the paper quality, thickness, and friction coefficient vary depending on the paper P.

For example, the coefficient of friction μ between paper sheets is 0.1.
There is a variation in the range of about 3 to 0.7, and multi-feeding is likely to occur on high-μ paper quality paper. If the return torque of the retard roller 57 is set high for high-μ paper, it is necessary to set the contact pressure of the retard roller 57 high at the same time. In addition, the damage to the paper increases.

For this reason, if the operating torque of the torque limiter 57b is set to be constant, the function of preventing the double feeding of the paper P in cooperation with the separation roller 56 may not be sufficient. In particular, in an image scanner, when a large number of originals are read, double feeding occurs. If an electronic file is read without reading even one of the originals, information to be stored is lacking. Is a very important issue.

Accordingly, an object of the present invention is to provide a sheet material supply mechanism capable of reliably preventing double feed according to the material of a sheet material such as paper by making the set torque of a retard roller variable. And

[0011]

SUMMARY OF THE INVENTION The present invention relates to a sheet material supply mechanism provided with a roller pair of a separation roller and a retard roller for preventing double feeding, which is disposed in a conveyance path of a sheet material such as paper. A plurality of torque limiters having different set torques are interposed between the retard roller and a shaft for driving the retard roller, and switching means for switching the plurality of torque limiters acting on the retard roller is provided.

In such a configuration, by switching a plurality of torque limiters acting on the retard roller in accordance with the material of the sheet material to be conveyed, the set torque of the retard roller is adjusted to match the material of the sheet material. And double feed of sheet materials of various materials can be prevented.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 is a sheet material supply mechanism provided with a roller pair of a separation roller and a retard roller for preventing double feeding, which is disposed in a conveyance path of a sheet material such as paper. Further, a plurality of torque limiters having different set torques are interposed between the retard roller and a shaft for driving the retard roller, and switching means for switching the plurality of torque limiters acting on the retard roller is provided. It is a sheet material supply mechanism.By switching a plurality of torque limiters acting on the retard roller, it is possible to adjust the set torque of the retard roller to match the material of the sheet material. Double feeding of the sheet material can be prevented.

According to a second aspect of the present invention, the switching means connects or disconnects the shaft and each of the plurality of torque limiters according to the rotation direction of the shaft. With the simple structure of controlling the rotation direction of the shaft, the set torque of the retard roller can be changed to prevent double feeding of the sheet material.

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 image scanner comprises a main body 1 containing a reading section of an optical system and a paper conveyance path, and an automatic paper feeder 2 as paper feeding means. The main body 1 has an operation panel 1a on the front thereof 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 completed 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 housing 2a in which a hopper 2b is rotatably assembled up and down via a hinge pin 2c. The hopper 2b is connected to an actuator (not shown) and rotates around the hinge pin 2c. Driven. That is, the papers P stacked and mounted on the hopper 2b are urged upward to a position where they come into contact with the supply roller 3 which is fixed at a fixed position above the hopper 2b and is driven to rotate. The upper surface of the hopper 2b is provided with a pair of guides 2d for guiding the paper P in the width direction, which can be manually moved in the frontage direction (the left-right direction when viewed from the front).

A pair of a separation roller 4 and a retard roller 5 for preventing double feeding of the paper P is disposed downstream of the supply roller 3 which picks up and feeds the paper P one by one on the hopper 2b. A transport path for the paper P is formed between the roller pair and the collection tray 1b. A plurality of pairs of transport rollers 6a and 6b for nipping and transporting the paper P are arranged in the transport path of the paper P, and a first scanning sensor for reading a document image on the upper surface of the paper P is provided in the middle. 7a and a second scanning sensor 7b for reading the original image on the lower surface
Has been arranged. Then, the supply roller 3 is supplied from the hopper 2b.
One sheet of paper P picked up by the scanner is read by the first and second scanning sensors 7a and 7b while passing through the transport path, and then discharged to the collection tray 1b.

FIG. 3 is a schematic view showing a main part of the set torque switching means of the retard roller 5.

As shown in FIG. 3, the retard roller 5 is driven by a retard motor (not shown). Between the output shaft 11 of the retard motor and the retard roller 5, there are gears 12a, 12b, 12c, a rotating shaft 13, gears 14a, 14b with one-way clutch, and gears 15a, 15b, 1
5c, 16a, 16b, rotating shafts 17a, 17b, and torque limiters 18a, 18b,
These constitute switching means for the set torque of the retard roller 5. The gear 12c is fixed to the rotating shaft 13, and the one-way clutch-equipped gears 14a and 14b are fixed to the rotating shaft 13 via a one-way clutch (not shown). The one-way clutch includes a rotating shaft 13 and a gear 14 with a one-way clutch in accordance with the rotation direction of the rotating shaft 13.
a and 14b, respectively, in a connected state or a non-connected state, and when the rotating shaft 13 rotates in the direction of the arrow in FIG. 3 (the retard motor rotates forward), the one-way clutch-equipped gear 14a is in the non-connected state. , The one-way clutch-equipped gear 14b is connected. On the other hand, when the rotating shaft 13 rotates in the direction opposite to the arrow in FIG.
4a is in a connected state, and the one-way clutch-equipped gear 14b is in a non-connected state. The rotating shaft 17a is fixed to the gear 15c, and the rotating shaft 17b is fixed to the gear 16b. The torque limiters 18a and 18b operate at different set torques T _A and T _B , respectively.
Retard roller 5 the rotation of the rotary shaft 17a in the torque T _A is
Transmitted to the torque limiter 18b is transmitted to the retard roller 5 the rotation of the rotating shaft 17b with a torque T _B.

In FIG. 3, when the retard motor rotates forward, the rotation of the output shaft 11 is controlled by the gears 12a, 12b, 12c.
Is transmitted to the rotary shaft 13 via the At this time, the gear 1 with the one-way clutch is operated by the action of the one-way clutch.
4b is connected to the rotating shaft 13 and the gears 16a, 16
Rotate b. Further, this rotation is transmitted to the retard roller 5 via the rotation shaft 17b and the torque limiter 18b. In other words, the retard roller 5 is actuated in the arrow direction in FIG. 3 a torque T _B by the action of the torque limiter 18b. On the other hand, the rotation of the retard roller 5 acts on the rotating shaft 17a via the torque limiter 18a, and is sequentially transmitted to the gears 15c, 15b, 15a and the gear 14a with a one-way clutch. At this time, the gear 14a with the one-way clutch is not connected to the rotating shaft 13 by the action of the one-way clutch.
It does not affect the rotation of 3.

Incidentally, since the retard roller 5 is in contact with the separation roller 4, if the original is not nipped between them or if only one original is nipped, as shown in FIG. The roller 5 rotates around the separation roller 4. At this time, the rotating shaft 17b
Generating a slip torque limiter 18b, exerts idling torque of the torque T _B the retard roller 5. On the other hand, the retard roller 5 includes a torque limiter 18a,
a, the gears 15c, 15b, and 15a are rotated in the directions of the arrows in FIG. 4, and the one-way clutch gear 14a attempts to rotate in the same direction as the rotating shaft 13 by the action of the one-way clutch. Therefore, in order for the rotating shaft 13 to idle without engaging with the gear 14a with a one-way clutch, the angular speed ω _S13 of the rotating shaft 13 and the angular speed ω _{g14a of the} gear 14a with the one-way clutch _{must satisfy} ω _{g 14a} > ω _S13 . That is, it is necessary that the gear 14 a with the one-way clutch rotates faster than the rotating shaft 13. Therefore, the rotation speed (peripheral speed) of the retard roller 5 when it rotates around
Is approximately the same as the peripheral speed of the separation roller 4, and if the speed ratio between the retard roller 5 and the separation roller 4 is set so that ω _g14a > ω _S13 , the rotation shaft 13 and the gear 14a with the one-way clutch are Never lock.

FIG. 5 is an explanatory diagram of the operation of the retard roller 5 when the retard motor rotates in the reverse direction.

In FIG. 5, when the retard motor rotates in the reverse direction, the rotation of the output shaft 11 is controlled by the gears 12a, 12b, 12b.
is transmitted to the rotating shaft 13 through the line c. At this time, the gear 14a with the one-way clutch is connected to the rotating shaft 13 by the action of the one-way clutch, and the gears 15a, 1
5b and 15c are rotated. Further, this rotation is transmitted to the retard roller 5 via the rotation shaft 17a and the torque limiter 18a. In other words, the retard roller 5 is actuated in the arrow direction in FIG. 5 a torque T _A by the action of the torque limiter 18a. On the other hand, the rotation of the retard roller 5 acts on the rotating shaft 17b via the torque limiter 18b, and is sequentially transmitted to the gears 16b and 16a and the gear 14b with a one-way clutch. At this time, the one-way clutch-equipped gear 14b is not connected to the rotating shaft 13 by the action of the one-way clutch, and thus does not affect the rotation of the rotating shaft 13.

When the operation button 1a-1 (see FIG. 1) of the operation panel 1a is turned on, the supply / separation motor (not shown) and the retard motor are started, and the supply roller 3 and the separation roller are turned on. The retard roller 4 and the retard roller 5 rotate in directions indicated by arrows in FIG.
However, as described above, the retard roller 5 and the separation roller 4
If the original is not nipped or only one original is nipped, the retard roller 5 rotates around the separation roller 4 (rotates in the direction opposite to the arrow in FIG. 2). When the separation roller 4 and the retard roller 5 nip one sheet of paper P, the retard motor is normally rotated so that the frictional force between the retard roller 5 and the sheet P has a torque that acts in the sheet feeding direction. The set torque of the retard roller 5 is switched to T _A or T _B by reversing the rotation. As a result, if the uppermost sheet P is picked up by the paper feed roller 3 from the hopper 2b, this one sheet P is immediately conveyed, and the first and second sheets P are conveyed.
After the original image is read by the scanning sensors 7a and 7b, the original is discharged to the collection tray 1b.

As described above, the retard roller 5 can set the rotation torque to T _A or T _B by switching the rotation direction of the output shaft 11 of the retard motor that drives the retard roller. Therefore, as described above, the separation roller 4
If the rotation torque is set in advance to T _A or T _B according to the material of the paper P so as to correspond to the frictional force acting on the retard roller 5 from one paper P when nipped between Normally, the retard roller 5, which rotates in the direction opposite to the sheet feeding direction, rotates in the sheet feeding direction. On the other hand, when two or more sheets of paper P are picked up by the supply roller 3, the load on the retard roller 5 is reduced because the sheets P are easily slipped. Therefore, the retard roller 5 continues to rotate in the direction of the arrow in FIG. 5, and the lower multi-feed sheet that is in contact with the peripheral surface can be returned to the hopper 2b.

As described above, when two or more sheets of paper P are picked up, only the uppermost sheet of paper P is fed out downstream by rotation of the retard roller and conveyed, and the remaining lower sheet of paper P is transferred to the hopper 2b side. Return to separate double feed roller 4
At the retard roller 5 portion. That is, by switching the set torque of the retard roller 5 to T _A or T _B according to the material (friction coefficient) of the paper P in advance, it is possible to prevent double feeding of paper P of various materials. At this time, the set torque of the retard roller 5 can be changed with a simple configuration in which the rotation direction of the output shaft 11 of the retard motor that drives the retard roller 5 is controlled.

By stopping the retard motor and holding the output shaft 11 in this embodiment,
It is possible to make the return torque of the retard roller 5 act as T _A + T _B. FIG. 6 is an explanatory diagram of the operation of the retard roller 5 when the retard motor is stopped.

In FIG. 6, when the retard motor stops and holds the output shaft 11, the rotating shaft 13 is locked, and a torque acts in the direction of the arrow shown in FIG. I do. The torque acting on the retard roller 5 is transmitted via torque limiters 18a and 18b at both ends thereof to the rotating shaft 17a, the gears 15c, 15b and 15a, the one-way clutch gear 14a and the rotating shaft 17b, the gears 16b and 16a, respectively. It acts on the one-way clutch gear 14b in the direction of the arrow in FIG. At this time, the gear 14 with the one-way clutch 14
Both a and 14b are in a connected state, and their torques cancel each other. Therefore, the set torque of the retard roller 5 is T _A + T _B which is the sum of the set torques T _A and T _B of the torque limiters 18a and 18b at both ends, and the load torque T _A + T _B prevents the document from entering. It acts as a torque to be tried, that is, a return torque.

[0032]

According to the present invention, the set torque of the retard roller can be switched in advance in accordance with the material (friction coefficient) of the sheet material to be conveyed, and the set torque of the retard roller is adapted to the material of the sheet material. So that double feeding of sheet materials of various materials can be prevented.

[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 schematic diagram showing a main part of a set torque switching unit of the retard roller.

FIG. 4 is an operation explanatory diagram when the retard roller rotates.

FIG. 5 is a diagram illustrating the operation of a retard roller when the retard motor rotates in the reverse direction.

FIG. 6 is an explanatory diagram of the operation of the retard roller when the retard motor is stopped.

FIG. 7 is a schematic diagram showing a conventional sheet feeding device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Main body 1a Operation panel 1a-1 Operation button 1b Collection tray 1c Frame 2 Automatic paper feeder 2a Housing 2b Hopper 2c Hinge pin 2d Guide 3 Supply roller 4 Separation roller 5 Retard roller 6a, 6b Transport roller 7a First scan sensor 7b 2 scanning sensors 11 output shafts 12a, 12b, 12c, 15a, 15b, 15c, 1
6a, 16b Gear 13, 17a, 17b Rotary shaft 14a, 14b Gear with one-way clutch 18a, 18b Torque limiter P Paper

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Junichi Suematsu 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. 3F343 FA02 FA03 FB01 FC01 GB01 GC01 GD01 JA01 JD09 JD33 JD34 LC19 LC25 LD30 MB14 MC21

Claims (2)

[Claims] 1. A sheet material supply mechanism comprising a roller pair of a separation roller and a retard roller for preventing double feeding arranged in a conveyance path of a sheet material such as a sheet, wherein the retard roller and the retard roller are provided. A plurality of torque limiters having different set torques are interposed between the shaft and a shaft for driving the roller, and switching means for switching the plurality of torque limiters acting on the retard roller is provided. 2. The apparatus according to claim 1, wherein the switching means connects or disconnects the shaft and each of the plurality of torque limiters in accordance with a rotation direction of the shaft.
A sheet material supply mechanism as described in the above.