JP2002002992A - 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 multi feed by automatically shifting 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 and 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 adjust the set torque of the retard roller 5, and the torque limiters 18a, 18b acting on the retard roller 5 are shifted according to the thickness of paper, detected with a sheet thickness detecting means, nipped with a separating roller 4 and 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. 10 is a schematic view showing a conventional paper feeder, and the one disclosed in the above-mentioned publication has substantially the same configuration.

In FIG. 10, a hopper 51 for mounting and setting paper P such as a document to be read or various documents is disposed at a base end of a reading line. A supply roller 52 for picking up and feeding out P is arranged. Hopper 51 is spring 51a
As a result, the paper P is pressed against the supply roller 52, and only the uppermost paper P can be fed out by friction with the peripheral surface thereof. Further, the pressing force against the supply roller 52 is kept substantially constant by the spring 51a even when the thickness of the stacked paper P changes.

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 of the paper P 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.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet supply mechanism capable of reliably preventing double feed by automatically switching a set torque of a retard roller.

[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 switching means for interposing a plurality of torque limiters having different set torques between the retard roller and a shaft for driving the retard roller to switch the plurality of torque limiters acting on the retard roller; and a nip formed by the roller pair. And a sheet thickness detecting means for detecting the thickness of the sheet material, and controlling the switching by the switching means in accordance with the thickness of the sheet material by the sheet thickness detecting means.

In such a configuration, a plurality of torque limiters acting on the retard roller are automatically switched according to the thickness of the sheet material to be conveyed, and the set torque of the retard roller is adjusted so that the multi-feed of the sheet material is performed. It can be prevented reliably.

[0013]

DETAILED 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 feed arranged in a conveyance path of a sheet material such as paper. Wherein a plurality of torque limiters having different set torques are interposed between the retard roller and a shaft for driving the retard roller, and a switching means for switching the plurality of torque limiters acting on the retard roller; and And a sheet thickness detecting means for detecting the thickness of the sheet material provided, and controlling the switching by the switching means in accordance with the thickness of the sheet material by the sheet thickness detecting means. By switching a plurality of torque limiters acting on the retard roller according to the thickness of the sheet material to be conveyed, the retard draw Setting by adjusting the torque, it becomes possible to prevent the double feeding the sheet material.

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.

According to a third aspect of the present invention, there is provided a nip force adjusting means for adjusting a nip force between the separation roller and the retard roller in accordance with switching by the switching means. It is a sheet material supply mechanism described in the above, and the nip force between the separation roller and the retard roller is changed according to the set torque of the adjusted retard roller, so that double feeding of the sheet material can be more reliably prevented. become.

Hereinafter, embodiments of the present invention will be described 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 of the present invention.

As shown in the figure, the image scanner comprises a main body 1 having a reading section of an optical system and a paper 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 includes a housing 2a and a hopper 2b rotatably assembled vertically 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 for picking up and feeding out 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 (a) is a side view of a main part, FIG. 3 (b) is a schematic view showing a posture of a cam when a winding degree of the torsion spring is reduced, and FIG. 3 (c) is a torsion spring. FIG. 4 is a schematic diagram showing a posture of a cam when a winding degree of the cam is increased.

As shown in FIG. 3A, the supply roller 3
And the separation roller 4 are rotatably mounted on a frame 1c fixed to the main body 1, respectively.
Is attached to a base 8 that rotates about a support shaft 8a fixed in the main body 1. This base 8 is the main body 1
Are urged counterclockwise with respect to the support shaft 8a by a tension spring 8d interposed therebetween. A rotatable sleeve 8b is extrapolated around the support shaft 8a,
A torsion spring 9 is wound around the sleeve 8b. The torsion spring 9 includes a winding portion 9a wound around the sleeve 8b and an engaging arm 9b and a biasing arm 9c protruding from the winding portion 9a in mutually different directions, as is conventionally known. The urging arm 9c is inserted and locked into an engaging hole 8c opened in the base 8, and the engaging arm 9b abuts on the peripheral surface of the cam 10 for adjusting the urging force.

The cam 10 is connected to a drive motor 10a,
It is rotationally driven as shown in (b) and (c) of FIG. In FIG. 5B, the degree of bending by the engagement arm 9b by the cam 10 is small, and the degree of winding of the winding portion 9a is also small. Therefore, the force for urging the base 8 upward by the urging arm 9c is also small. On the other hand, when the cam 10 is rotated in the direction of the arrow as shown in (c) of the figure, the winding degree of the winding portion 9a increases, and the urging force of the urging arm 9c against the base 8 increases accordingly.

As described above, the cam 10 is connected to its driving motor 10
By rotating and driving according to a, the biasing force of the torsion spring 9 can be changed. Therefore, the pressing force of the retard roller 5 on the separation roller 4 can be increased or decreased, and the nip force on the sheet P can be set arbitrarily.

FIG. 4 is a schematic view showing a main part of the set torque switching means of the retard roller 5. As shown in FIG.

As shown in FIG. 4, 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. 4 (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. 4, when the retard motor rotates forward, 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 14b with the one-way clutch is connected to the rotating shaft 13 by the action of the one-way clutch, and the gears 16a, 1
6b is rotated. 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 of FIG. 4 in 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 rotation shaft 17a via the torque limiter 18a, and
The power is transmitted to the gears 15c, 15b, 15a and the gear 14a with a one-way clutch. At this time, the one-way clutch-equipped gear 14a 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.

FIG. 5 is an explanatory view of the operation when the retard roller rotates. The retard roller 5 is a separation roller 4
When the document is not nipped between them, or when only one document is nipped between them, the retard roller 5 rotates around the separation roller 4 as shown in FIG. . 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, 15a are rotated in the direction of the arrow in FIG. 5, and the one-way clutch-equipped gear 14a tries 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 one-way clutch gear 14a, the angular speed ω _S13 of the rotating shaft 13 and the angular speed ω _g14a of the one-way clutch gear 14a _{must satisfy} ω _g14a > ω _S13 , that is, It is necessary that the one-way clutch gear 14a 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. 6 is an explanatory view of the operation of the retard roller 5 when the retard motor rotates in the reverse direction.

In FIG. 6, when the retard motor rotates reversely, 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 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.

FIG. 7 is an explanatory diagram of the operation of the retard roller 5 when the retard motor is stopped.

In FIG. 7, when the retard motor stops and holds the output shaft 11, the rotating shaft 13 is locked, and a torque is applied to the retard roller 5 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 desired torque, that is, a return torque.

Here, the conditions for setting the set torques T _A and T _B of the torque limiters 18a and 18b will be described with reference to FIG.

As shown in FIG. 8A, F: pressing force of the retard roller 5, N: pressing force of the feed roller 3, μ: coefficient of friction between the separation roller 4 and the retard roller 5 and the paper P , Μ _F : coefficient of friction between sheets P, set torque T of retard roller 5, r: radius of retard roller 5, F> (1 / μ) × (T / r) + (μ _F −μ ) / Μ × N (1) When the condition of F <(1 / μ _F ) × (T / r) −2 × N (2) is satisfied, one sheet P is retarded. Roller 5
When the sheet is nipped between the sheet and the separation roller 4, the torque T becomes a torque at which the frictional force between the retard roller 5 and the sheet P acts in the sheet feeding direction. On the other hand, when two or more sheets P are nipped, the torque T causes the retard roller 5 to return the sheet P in contact with the sheet P to the hopper 2b, against the frictional force acting between the sheets P. Acting torque.

Therefore, the torque T in the region satisfying both the above expressions (1) and (2) (the normal separation region in FIG. 8B) is set as the set torques T _A and T _B of the retard roller 5. However, the set torques T _A and T _B satisfy T _A <T _B.

The image scanner according to the present embodiment includes a sheet thickness detecting means (not shown) for detecting the thickness of the sheet P nipped by the separation roller 4 and the retard roller 5. The sheet thickness detecting means may be provided immediately after the nip point between the separation roller 4 and the retard roller 5, and may detect the thickness of the nipped sheet P. For example, it can be constituted by a displacement meter or the like.

When the operation button 1a-1 (see FIG. 1) of the operation panel 1a is turned on in the image scanner having the above configuration, a supply / separation motor (not shown) and a retard motor are activated, and the supply roller 3 and the separation roller 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
When the original is not nipped between the rollers, the retard roller 5 rotates around the separation roller 4 (rotates in the direction opposite to the arrow in FIG. 2). At this time, the torque acting on the retard roller 5 by the normally rotating retard motor is T _A. When the uppermost thin sheet P (for example, about 0.05 mm thick) is picked up by the sheet feed roller 3 from the hopper 2b and the separation roller 4 and the retard roller 5 nip, the retard roller 5 and the sheet P The torque is such that the frictional force acts in the paper feeding direction. Therefore, the retard roller 5, which is rotating in the direction opposite to the paper feeding direction in normal times, rotates in the paper feeding direction, and this one sheet of paper P is quickly conveyed. After the original image is read by the first and second scanning sensors 7a and 7b, the original is discharged to the collection tray 1b.

On the other hand, when two or more thin papers P are picked up by the supply roller 3, or two or more thick papers (for example, about 0.1 mm or more) are picked up by the supply roller 3. When done
The sheet thickness of two or more sheets is detected by the sheet thickness detecting means. Here, FIG. 9 shows a time chart for switching the set torque of the retard roller.

When two or more sheet thicknesses are detected by the sheet thickness detecting means as shown in FIG.
As shown in (b), the retard motor is switched from the normal rotation state to the stop state. As a result, the rotation of the retard roller 5 stops. At this time, the set torque of the retard roller 5 is T _A + T _B as shown in FIG.
Acts as a frictional force against Thereafter, as shown in FIG. 9B, the retard motor is switched from the stop state to the reverse rotation state. Thus, the set torque of the retard roller 5 becomes T _B.

[0041] This setting torque T _B, when two or more thin sheet P enters the nip point is picked up by the feed roller 3 acts stronger return torque on the paper P, tends to separate the sheet P . The friction coefficient between the sheets P is about μ = 0.3 to 0.7. As described above, the larger the friction coefficient μ is, the easier it is to feed multiple sheets.
_A is a value suitable for paper with a small friction coefficient μ, and set torque T _B
By setting a value appropriate for the large paper friction coefficient μ a, which seeks to act on the set torque T _B as return torque when paper friction coefficient μ is large is double feeding.

On the other hand, when a sheet of thick paper sheet thickness of at least two sheets enters the nip point is picked up by the feed roller 3 is returning torque T _B acts generally thicker sheet of paper thickness The rigidity is high and the damage to the paper is small even when a strong return torque is applied. That is, since when exerting a strong return torque in a thin sheet of paper thickness damage to the paper becomes a problem, usually should be set to set torque T _A suitable thin sheet, a large coefficient of friction μ in a thin sheet paper by the action of strong returning torque T _B only when the double feed has been the case or thick paper enters, is obtained so as to prevent double feeding.

As described above, in the normal state, the retard motor is set to the normal rotation state, and the set torque of the retard roller 5 is T _A.
And to advance, by switching the set torque of the retard roller 5 to T _B when paper thickness of more than two sheets by the sheet thickness detecting means is detected, a thin paper P one sheet is picked up by the feed roller 3 Only when this occurs, the torque acting on the paper P is T _A. Meanwhile, the torque acting on the sheet P when the two or more thin sheet P or two sheets or more thick sheet is picked up becomes T _B. Therefore, the torque acting on one thin sheet P can be prevented from being damaged as a low torque T _A , and the torque acting on the multi-feed of the sheets P or the thick sheet can be a high torque T _B. As a result, it is possible to further enhance the double feed prevention effect. Further, the set torque of the retard roller 5 can be changed by 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 the way, as shown in FIG. 8B, as the set torque T of the retard roller 5 increases, the range of the normal separation region moves upward. Accordingly, when switching the set torque of the retard roller 5 from a low torque T _A to a higher torque T _B, it is desirable to switch the pressing force F of the separation roller 4 at the same time. At this time, it is desirable to set the optimum pressure to be in the center of the normal separation region, and the optimum pressures at the set torques T _A , T _B , T _A + T _B are F _A , F _B , and F _{A +} , respectively. _B.

The switching of the pressing force F can be performed, for example, by the method shown in FIG.
Although the adjustment can be performed using the biasing force adjusting mechanism of the retard roller 5 described in the above, the biasing force of the separation roller 4 may be adjusted using a similar mechanism. That is,
By adjusting the nip force between the separation roller 4 and the retard roller 5 in accordance with the switching of the set torque of the retard roller 5, double feeding of the sheet material can be more reliably prevented.

[0046]

According to the present invention, a plurality of torque limiters acting on the retard roller are automatically switched in accordance with the thickness of the sheet material to be conveyed, and the set torque of the retard roller is adjusted to thereby reduce the weight of the sheet material. Sending can be reliably prevented.

In addition, the nip force between the separation roller and the retard roller is adjusted in accordance with the switching of the torque limiter, so that the distance between the separation roller and the retard roller is adjusted in accordance with the set torque of the adjusted retard roller. Nip force can be changed to more reliably prevent double feed.

[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.

3A is a side view of a main part. FIG. 3B is a schematic view showing a posture of a cam when a winding degree of a torsion spring is reduced. Schematic

FIG. 4 is a schematic view showing a main part of a set torque switching unit of the retard roller.

FIG. 5 is an operation explanatory diagram when the retard roller rotates.

FIG. 6 is an explanatory diagram of the operation of the retard roller when the retard motor rotates in the reverse direction.

FIG. 7 is an explanatory diagram of the operation of the retard roller when the retard motor is stopped.

8A is a diagram showing a relationship between a pressing force and a frictional force of a supply roller, a separation roller, and a retard roller. FIG. 8B is a diagram showing a relationship between a pressing force of a separation roller, a set torque of the retard roller, and a normal separation region. Illustration

FIG. 9 is a time chart of switching the set torque of the retard roller.

FIG. 10 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 sensor 8 base 8a support shaft 8b sleeve 8c engagement hole 8d spring 9 torsion spring 9a winding portion 9b engagement arm 9c biasing arm 10 cam 10a drive motor 11 output shaft 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 (reference) in Matsushita Electric Industrial Co., Ltd. 3F343 FA02 FA03 FB01 FC01 GA01 GB01 GC01 GD01 JA01 JD09 JD33 JD34 LC06 LC19 LD30 MA27 MB14 MC11 MC21

Claims (3)

[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 the driving shaft, and a switching unit that switches the plurality of torque limiters acting on the retard roller, and a thickness of the sheet material nipped by the roller pair is set. A sheet thickness detecting means for detecting the sheet thickness, wherein the switching by the switching means is controlled in accordance with the thickness of the sheet material by the sheet thickness detecting means. 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. 3. A nip force adjusting means for adjusting a nip force between the separation roller and the retard roller in accordance with the switching by the switching means.
Or a sheet material supply mechanism according to 2.