JP2022075728A - Medium feeding device and image reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medium feeding device that can correct skew of transported media efficiently and reliably while avoiding the upsizing of the device, and an image reading device provided with the same.

SOLUTION: It includes a first roller 14a and a second roller 14b provided with space in between in the width direction intersecting the medium feeding direction, and a feeding roller 14 that feeds paper P from a medium mounting unit 11 on which the paper P is mounted, a skew detection unit 21 that detects the skew of the paper fed from the feeding roller 14, and a control unit 19 that controls the movement of the feeding roller 14. The control unit 19, based on the skew amount of paper P1 as the first medium detected by the skew detection unit 21, can execute skew correction control that corrects the skew by making a difference on the rotating speed R1 of the first roller 14a and the rotating speed R2 of the second roller 14b with respect to the paper P1 and at least one of the paper P2 etc thereafter to be fed subsequently.

SELECTED DRAWING: Figure 6

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present invention relates to a medium feeding device that feeds a medium and an image reading device that reads an image of a medium fed by the medium feeding device.

A scanner, which is an example of an image reading device, is provided with a medium feeding device (also called an ADF (Auto Document Feeder)) that automatically sends a medium (original document), and a plurality of media set in a medium tray are set as one sheet. Some are configured to automatically feed the images one by one so that the image can be continuously read by the reading unit.
In such a scanner, when the medium is fed toward the reading unit by the medium feeding device, skew (also referred to as skewing) in which the medium is sent diagonally may occur. If the medium is skewed, paper jam may occur in the transport path, or the image read by the reading unit may be skewed.

Therefore, a medium sensor for detecting the medium to be conveyed is provided, and the skew of the medium is detected by the medium sensor, and the skew correction for sending the medium so as to correct the skew according to the detected skew amount. A scanner including a medium feeding device configured to perform processing has been proposed (for example, Patent Document 1).

In Patent Document 1, the skew correction process is performed by controlling the drive of a pair of resist rollers provided at intervals in the width direction intersecting the medium transport direction. Specifically, in the resist roller pair, one resist roller and the other resist roller are rotationally driven by independent motors, and there is a difference in the rotational speed between one resist roller and the other resist roller. By attaching, the skew of the medium is corrected.

Japanese Unexamined Patent Publication No. 2011-071763

Here, in Patent Document 1, the resist roller pair that corrects the skew of the medium is provided in the medium transport path on the downstream side of the delivery roller that sends out the medium set in the medium tray. Therefore, the skew of the medium cannot be corrected in the section between the sending roller and the resist roller pair.

The medium delivered from the medium tray by the delivery roller may be largely skewed in the section where the skew cannot be corrected. Therefore, it is necessary to widen the path width to the resist roller pair in anticipation of skew, which leads to an increase in the size of the apparatus.

Further, in Patent Document 1, on the upstream side of the resist roller pair, a separation roller pair that separates a plurality of media into one when a plurality of media are fed from the medium tray is provided. When the skew of the medium is corrected by the resist roller pair, since the rear end side of the medium is nipped by the separation roller pair, the rotation speeds of one resist roller and the other resist roller of the resist roller pair. Even if there is a difference, the medium cannot move in the direction of correcting the skew, and there is a possibility that the skew cannot be corrected or becomes insufficient.

The present invention has been made in view of such a situation, and an object of the present invention is to efficiently and reliably correct the skew of the conveyed medium while avoiding an increase in the size of the apparatus. It is an object of the present invention to provide an apparatus and an image reading apparatus comprising the apparatus.

The medium feeding device according to the first aspect of the present invention for solving the above problems includes a processing unit for processing the medium and a pair of first rollers provided in a width direction intersecting the medium feeding direction. A feeding unit provided with a second roller and feeding the medium from the medium mounting section on which the medium is placed toward the processing section and a skew of the medium fed from the feeding section are detected. The skew detection unit includes a control unit that controls the operation of the feeding unit, and the control unit is based on the skew amount in the first medium detected by the skew detection unit. The skew of the medium and at least one of the next and subsequent media fed following the first medium with a difference between the rotation speed of the first roller and the rotation speed of the second roller. It is characterized in that it is possible to execute skew correction control for correcting.

According to this aspect, the control unit is continuously fed to the first medium or the first medium based on the skew amount in the first medium detected by the skew detection unit. Since it is possible to execute skew correction control that makes a difference between the rotation speed of the first roller and the rotation speed of the second roller for the medium after the next rank, the supply provided on the most upstream side of the medium transport path. The skew of the medium can be corrected at the position of the feeding unit. That is, the skew of the medium can be corrected at an early stage after the start of feeding from the medium mounting portion. Therefore, the skew of the medium can be efficiently corrected.
Further, it is not necessary to secure a wide path width of the medium transport path in anticipation of skew, and it is possible to avoid an increase in the size of the apparatus.
Further, after the medium is started by the feeding section, the medium can rotate freely until the tip of the medium reaches the transport position by the next transport section, so that the effect of the skew correction control is surely obtained. can get.

A second aspect of the present invention is characterized in that, in the first aspect, the control unit stops either the first roller or the second roller when the skew correction control is executed. And.

According to this aspect, when the control unit executes the skew correction control, the rotation speed of the first roller and the first roller are obtained by stopping either the first roller or the second roller. It is possible to make a difference from the rotation speed of the two rollers.

A third aspect of the present invention is, in the first aspect or the second aspect, the skew detection unit is provided between the feeding unit and the processing unit and is one of the transport units for transporting the medium. , It is characterized in that it is arranged on the upstream side of the upstream side transport portion provided on the most upstream side.

According to this aspect, the skew detection unit is upstream of the upstream transport unit provided on the most upstream side of the transport units provided between the feed unit and the processing unit to transport the medium. Since it is arranged on the side, the control unit has a configuration capable of executing the skew correction control on the first medium based on the skew amount in the first medium detected by the skew detection unit. be able to.

A fourth aspect of the present invention is that, in the third aspect, the skew detection unit overlaps a part of the feeding unit on the downstream side of the position where the feeding unit applies a feeding force to the medium. It is characterized by being placed in.

According to this aspect, the skew of the medium fed by the feeding unit can be detected early after the start of feeding.

A fifth aspect of the present invention is, in any one of the first to fourth aspects, the skew detection unit is provided at intervals in the width direction, and the first medium detection capable of detecting the medium is possible. It is characterized in that it is configured to include a unit and a second medium detection unit.

According to this aspect, an image reading including the skew detection unit provided at intervals in the width direction and including a first medium detection unit and a second medium detection unit capable of detecting the medium. In the apparatus, the same action and effect as any one of the first to the fourth aspects can be obtained.

A sixth aspect of the present invention is, in any one of the first to fifth aspects, the first drive source for driving the first roller and the second drive source for driving the second roller. It is characterized by being prepared.

According to this aspect, since the first roller and the second roller are each driven by individual drive sources, skew correction control that makes a difference between the rotation speed of the first roller and the rotation speed of the second roller. Can be easily performed.

A seventh aspect of the present invention is, in any one of the first to fifth aspects, a first drive source, a second drive source for driving the second roller, and a drive for driving the first roller. The control unit, which includes a switching mechanism for switching the source between the first drive source and the second drive source and controls the operation of the switching mechanism, switches the source when executing the skew correction control. When the mechanism is set to the first state in which the first roller is driven by the first drive source and the skew correction control is not executed, the switching mechanism is driven by the first roller by the second drive source. It is characterized in that the second state is set.

According to this aspect, when the control unit executes the skew correction control, the switching mechanism is set to the first state in which the first roller is driven by the first drive source. The roller and the second roller can be driven by individual drive sources. Therefore, skew correction control that makes a difference between the rotation speed of the first roller and the rotation speed of the second roller can be easily performed.

Further, when the skew correction control is not executed, for example, it is desirable that the first roller and the second roller rotate at a constant speed during normal feeding.
According to this aspect, the control unit puts the switching mechanism in the second state in which the first roller is driven by the second drive source when the skew correction control is not executed. The rotation speed of the roller and the rotation speed of the second roller can be easily made the same.

An eighth aspect of the present invention is, in the seventh aspect, on a first rotating shaft on which the first roller is fixed and rotated by receiving power from the first drive source, and on the same axis as the first rotating shaft. The second roller is fixed to the second rotating shaft, and the second rotating shaft is provided with a second rotating shaft that rotates by receiving power from the second drive source. The switching mechanism includes the first rotating shaft and the second rotating shaft. The first state is separated and rotated individually, and the transmission of power from the first drive source to the first rotation shaft is cut off, and the first rotation shaft and the second rotation shaft are connected to each other. It is characterized in that it is configured to switch between the second state of being integrally rotated.

According to this aspect, the first state in which the first rotation shaft and the second rotation shaft are separated and individually rotated, and the transmission of power from the first drive source to the first rotation shaft are cut off. At the same time, the configuration of the seventh aspect can be realized by the switching mechanism having a configuration for switching between the second state in which the first rotating shaft and the second rotating shaft are connected and integrally rotated.

A ninth aspect of the present invention is characterized in that, in the eighth aspect, the switching mechanism is configured to include an electromagnetic clutch.
According to this aspect, a configuration for switching between the first state and the second state can be easily realized.

The medium feeding device according to any one of claims 1 to 9, wherein the image reading device according to the tenth aspect of the present invention includes a reading unit for reading a medium and the reading unit as the processing unit. It is characterized by having.
According to this aspect, in an image reading device provided with a reading unit for reading an image of a medium, the same effect as any one of the first to ninth aspects can be obtained.

An eleventh aspect of the present invention is characterized in that, in the tenth aspect, the reading unit also serves as the skew detecting unit.
According to this aspect, since the reading unit also serves as the skew detecting unit, the number of parts can be reduced and the manufacturing cost can be reduced.

The external perspective view which shows the scanner which concerns on this invention. A perspective view of the scanner according to the present invention as viewed from a different angle from FIG. The side sectional view which shows the paper transport path in the scanner which concerns on this invention. The perspective view which shows the state which opened the upper unit of the scanner which concerns on this invention. The schematic plan view of the paper transport path in the scanner which concerns on this invention. The figure explaining the detection of skewed paper in a skew detection part. A flowchart illustrating a flow from the start of feeding by the feeding roller to the determination of whether or not to perform skew correction control by the control unit. A flowchart illustrating the flow of skew correction control executed by the control unit. The perspective view which shows the drive mechanism of the 1st roller and the 2nd roller. The cross-sectional view which shows the drive mechanism of the 1st roller and the 2nd roller. FIG. 5 is a cross-sectional view showing another example of the drive mechanism of the first roller and the second roller.

[First Embodiment]
First, an outline of an image reading device including a medium feeding device according to an embodiment of the present invention will be described.
In the present embodiment, as an example of the image reading device, a document scanner (hereinafter, simply referred to as scanner 1) capable of reading at least one of the front surface and the back surface of the paper as a “medium” will be given as an example.

FIG. 1 is an external perspective view showing a scanner according to the present invention. FIG. 2 is a perspective view of the scanner according to the present invention as viewed from a different angle from that of FIG. FIG. 3 is a side sectional view showing a paper transport path in the scanner according to the present invention. FIG. 4 is a perspective view showing a state in which the upper unit of the scanner according to the present invention is opened. FIG. 5 is a schematic plan view of a paper transport path in the scanner according to the present invention. FIG. 6 is a diagram illustrating detection of skewed paper in the skew detection unit.

FIG. 7 is a flowchart illustrating a flow from the start of feeding by the feeding roller to the determination of whether or not to perform skew correction control by the control unit. FIG. 8 is a flowchart illustrating a flow of skew correction control executed by the control unit. FIG. 9 is a perspective view showing the drive mechanism of the first roller and the second roller. FIG. 10 is a cross-sectional view showing the drive mechanism of the first roller and the second roller. FIG. 11 is a cross-sectional view showing another example of the drive mechanism of the first roller and the second roller.

In the XYZ coordinate system shown in each figure, the X direction is the device width direction, the paper width direction, and the Y direction is the paper transport direction. The Z direction is a direction that intersects with the Y direction, and indicates a direction that is approximately orthogonal to the surface of the paper to be conveyed. Further, the + Y direction side is the front side of the device, and the −Y direction side is the back side of the device. Further, the left side is the + X direction and the right side is the −X direction when viewed from the front side of the device. Further, the + Z direction is the upper side of the device (including the upper part, the upper surface, etc.), and the −Z direction side is the lower side of the device (including the lower part, the lower surface, etc.). Further, the direction in which the paper is fed (+ Y direction side) is referred to as "downstream", and the opposite direction (-Y direction side) is referred to as "upstream".

■■■ Overview of Scanner ■■■
Hereinafter, the scanner 1 according to the present invention will be described mainly with reference to FIGS. 1 and 2.
The scanner 1 shown in FIGS. 1 and 2 includes a reading unit 20 (FIG. 3) as a “processing unit” that processes paper P (medium) inside the apparatus main body 2. The process performed by the reading unit 20 on the paper P is an image reading process for reading an image on the paper P (medium).
The apparatus main body 2 includes a lower unit 3 and an upper unit 4. The upper unit 4 is attached to the lower unit 3 so as to be openable and closable with the downstream side in the paper transport direction as a rotation fulcrum, and the upper unit 4 is rotated to open toward the front side of the device to expose the paper transport path of the paper P. It is configured so that the paper jam of the paper P can be easily cleared.

On the back surface side (-Y-axis direction side) of the apparatus main body 2, a medium placing portion 11 on which the paper P is placed is provided. Reference numeral 11a is a mounting surface 11a of the paper P.
Inside the device main body 2, a medium feeding device 10 (FIG. 3) for feeding the paper P from the medium mounting section 11 toward the reading section 20 is provided.
In the scanner 1, the medium mounting portion 11 is detachably provided with respect to the apparatus main body 2. The detailed configuration of the medium feeding device 10 will be described later.

Further, the medium mounting portion 11 is provided with a pair of left and right edge guides 12, 12 having guide surfaces 13 for guiding side edges in the width direction (X-axis direction) intersecting the feeding direction (Y-axis direction) of the paper P. Is provided.
The edge guides 12 and 12 are provided so as to be slidable in the X-axis direction according to the size of the paper P. In the present embodiment, the edge guides 12 and 12 follow the X movement of one edge guide 12 (for example, + X side) by a known rack and pinion mechanism, and the direction in which the other edge guide 12 (−X side) faces each other. It is configured to move to.
That is, in the medium mounting portion 11, the paper P is aligned in the center in the width direction, and the feeding roller 14 described later is provided in the center region in the width direction so that the paper is fed by the so-called center feeding method. It is configured. FIG. 1 shows a state in which the edge guides 12 and 12 are in the outermost positions, and FIG. 2 shows a state in which the edge guides 12 and 12 are in the innermost position.

The medium mounting unit 11 includes a first auxiliary paper support 8 and a second auxiliary paper support 9. The first auxiliary paper support 8 and the second auxiliary paper support 9 can be stored inside the medium mounting portion 11 as shown in FIG. 2, and can be pulled out from the medium mounting portion 11 as shown in FIG. The length of the mounting surface 11a can be adjusted.

The apparatus main body 2 is provided with an operation panel 7 on the front side of the apparatus of the upper unit 4 for displaying various reading settings, reading execution operations, reading setting contents, and the like.
A feeding port 6 connected to the inside of the device main body 2 is provided on the upper part of the upper unit 4, and the paper P placed on the medium mounting portion 11 is read from the feeding port 6 inside the device main body 2. It is sent toward the unit 20 (FIG. 3).
Further, a paper ejection tray 5, which will be described later, is provided on the front side of the device of the lower unit 3.

■■■ About the paper transport route in the scanner ■■■
Next, the paper transport path in the scanner 1 will be described mainly with reference to FIG. The dotted line in FIG. 3 indicates the transport path of the paper P.
In the scanner 1, the paper P, which is a document, is sent from the medium mounting unit 11 toward the reading unit 20 by the medium feeding device 10.

In the present embodiment, the medium feeding device 10 shown in FIG. 3 has a feeding roller 14 as a “feeding section” for feeding the paper P placed on the medium loading section 11 toward the reading section 20 and a feeding roller 14. A skew detecting unit 21 for detecting the skew of the paper P fed from the feed roller 14 and a control unit 19 for controlling the operation of the feed roller 14 are provided.

As shown in FIG. 4, the feeding roller 14 includes a first roller 14a and a second roller 14b provided in pairs in the width direction (X-axis direction) intersecting the medium feeding direction (+ Y direction). It is composed of.
The present invention is characterized in controlling the operation of the feeding roller 14 (first roller 14a and second roller 14b) by the control unit 19 based on the detection information by the skew detection unit 21.
The control of the control unit 19 based on the detection information by the skew detection unit 21 and the skew detection unit 21 will be described in detail after the description of the paper transport path.

In the medium feeding device 10, a separation roller 15 is provided at a position facing the feeding roller 14 provided on the downstream side of the medium mounting portion 11 to nip and separate the paper P from the feeding roller 14. Has been done. As shown in FIG. 5, the separation roller 15 also includes a pair of first separation rollers 15a and a second separation roller 15b corresponding to the pair of first rollers 14a and second rollers 14b constituting the feeding roller 14. There is.
As shown in FIG. 5, the feeding roller 14 and the separating roller 15 are provided in the central region in the width direction (X-axis direction) (see also FIG. 4 for the feeding roller 14).

Returning to FIG. 3, the paper P placed on the medium mounting portion 11 is picked up by the feeding roller 14 rotatably provided for the lower unit 3 and fed to the downstream side (+ Y direction side). To. Specifically, the paper P is fed toward the downstream side by rotating while the feeding roller 14 is in contact with the surface of the paper P facing the medium mounting portion 11. Therefore, when a plurality of sheets P are set in the medium mounting portion 11 in the scanner 1, the sheets P are sequentially fed from the paper P on the mounting surface 11a side toward the downstream side.

On the downstream side of the feeding roller 14, a transport roller pair 16, a reading unit 20, and a discharge roller pair 17 are provided.
The transport roller pair 16 is provided on the upstream side of the reading unit 20, and conveys the paper P fed by the feeding roller 14 toward the reading unit 20. The transfer roller pair 16 includes a transfer drive roller 16a and a transfer driven roller 16b.
As shown in FIG. 5, the transport roller pair 16 and the discharge roller pair 17 are also provided in the central region in the medium width direction (convey drive roller 16a and discharge drive roller 17a described later), similarly to the feed roller 14. See also Fig. 4).

The reading unit 20 includes an upper reading sensor 20a provided on the upper unit 4 side and a lower reading sensor 20b provided on the lower unit 3 side. In the present embodiment, the upper reading sensor 20a and the lower reading sensor 20b are configured as a close contact type image sensor module (CISM) as an example.

After the image of at least one of the front surface and the back surface of the paper P is read by the reading unit 20, the paper P is nipped into the discharge roller pair 17 located on the downstream side of the reading unit 20 and is nipped into the apparatus of the lower unit 3. It is discharged from the discharge port 18 provided on the front side. The discharge roller pair 17 includes a discharge drive roller 17a and a discharge driven roller 17b.

In the present embodiment, the feed roller 14, the transport drive roller 16a, and the discharge drive roller 17a are rotationally driven by at least one drive source (not shown) provided in the lower unit 3. Further, the drive source (not shown) is controlled by the control unit 19, whereby the drive of the feed roller 14, the transport drive roller 16a, and the discharge drive roller 17a is controlled. That is, the control unit 19 controls the feeding operation of the paper P.

The lower unit 3 is provided with a paper discharge tray 5 configured to be able to be pulled out from the discharge port 18 toward the front side of the device. The output tray 5 may be stored in the bottom of the lower unit 3 (FIG. 1) or pulled out to the front side of the device (not shown). With the paper ejection tray 5 pulled out, the paper P ejected from the ejection port 18 can be loaded on the paper ejection tray 5.

As shown in FIG. 3, the paper to be mounted on the medium mounting section 11 is located on the upstream side of the feeding roller 14 in the medium feeding direction and in the paper loading area by the medium loading section 11. A first detection unit 22 for detecting the presence or absence of P is provided. Further, a second detection unit 23 and a third detection unit 24 are provided in this order on the downstream side of the transport roller pair 16 and the downstream side of the discharge roller pair 17. The second detection unit 23 and the third detection unit 24 can detect the position of the paper P in the medium feeding direction.
The first detection unit 22, the second detection unit 23, and the third detection unit 24 can be provided, for example, in the central region in the width direction.

■■■ About the skew detector ■■■

As shown in FIGS. 4 and 5, the skew detection unit 21 is arranged on the upstream side of the transport roller pair 16 and on the downstream side of the feed roller 14 in the medium transport direction (+ Y direction). In the present embodiment, the transport roller pair 16 is an "upstream transport section" provided on the most upstream side of the transport sections provided between the feed roller 14 and the reading section 20 to transport the paper P. .. When there is another transport roller pair (transport unit) between the feed roller 14 and the transport roller pair 16, the skew detection unit 21 is arranged on the upstream side of the other transport roller pair.
This makes it possible to detect the skew of the paper P fed by the feeding roller 14 at an early stage after the start of feeding.

Further, in the present embodiment, as shown in FIG. 5, the skew detection unit 21 partially overlaps with the feed roller 14 at the position y1 in the medium transport direction.
More specifically, the skew detection unit 21 is located on the downstream side of the first position N1, which is the position where the feeding roller 14 applies the feeding force to the paper P, that is, the nip position of the feeding roller 14 and the separation roller 15. Is arranged so as to overlap a part of the feeding roller 14.
As described above, since the skew detection unit 21 is provided immediately downstream of the first position N1, the paper P sent to the downstream side after being fed by the feeding roller 14 can be detected at an earlier stage. It has become.

Further, the skew detection units 21 are provided in pairs at intervals so as to be located on both sides of the feeding roller 14 in the width direction (X-axis direction).
Of the pair of skew detection units 21, the + X direction side is the first medium detection unit 21a, and the −X direction side is the second medium detection unit 21b. The first medium detection unit 21a and the second medium detection unit 21b are configured to be able to detect the medium, respectively.

In the present embodiment, the first medium detection unit 21a and the second medium detection unit 21b include a light emitting unit that emits light (not shown) and a light receiving unit that receives the reflected light of the light emitted from the light emitting unit (not shown). ) Is used.
In addition to the optical sensor, the first medium detection unit 21a and the second medium detection unit 21b are provided with a transmission unit that emits ultrasonic waves and a reception unit that faces the transmission unit with the conveyed paper sandwiched between them. It is also possible to use an ultrasonic sensor equipped with. Further, a lever type sensor that optically or electrically detects the displacement of the mechanical lever moved by the contact of the conveyed paper can also be used.
The same medium sensor can be used for the first detection unit 22, the second detection unit 23, and the third detection unit 24 described above.

The skew (oblique) in which the tip of the paper is conveyed diagonally is determined by the presence or absence of detection of the paper by the first medium detection unit 21a and the second medium detection unit 21b.
As shown in FIG. 5, when the paper P is conveyed straight without skewing, the tip of the paper is detected by both the first medium detection unit 21a and the second medium detection unit 21b almost at the same time. However, in FIG. 6, when the paper is skewed like the paper P1 shown by the alternate long and short dash line, the paper is detected first by one (first medium detection unit 21a) and delayed by the other (second medium detection unit 21b). Is detected. In FIG. 6, the reference numeral P1 indicated by the dotted line indicates the paper in a normally conveyed state.

The time from the start of feeding by the feeding roller 14 until the paper P is detected by the first medium detection unit 21a (hereinafter referred to as detection timing t1) and the second medium after the start of feeding by the feeding roller 14. When there is a deviation (t1-t2 = Δt) in the time until the paper P is detected by the detection unit 21b (hereinafter referred to as detection timing t2), the control unit 19 determines that the paper P has been skewed. do.
When Δt is short, it is not determined to be skew, and when it exceeds a predetermined threshold value, it can be determined to be skew.

In the present embodiment, the "skew correction control" in which the control unit 19 corrects the deviation (Δt) of the detection timing of the paper P between the first medium detection unit 21a and the second medium detection unit 21b as the skew amount. To execute.

■■■ Control by the control unit ■■■
Next, the control of the feeding roller 14 by the control unit 19 based on the detection result by the skew detection unit 21 will be described.
The control unit 19 is fed to the paper P1 (FIG. 6) and the paper P1 based on the skew amount (Δt) of the paper P1 as the “first medium” detected by the skew detection unit 21. There is a difference between the rotation speed R1 of the first roller 14a of the feeding roller 14 and the rotation speed R2 of the second roller 14b of the feeding roller 14 with respect to at least one of the following sheets P2 (not shown). It is possible to execute "skew correction control" to correct the skew by attaching it.

The first roller 14a and the second roller 14b constituting the feeding roller 14 can be rotated at a constant speed, and can also be rotated at different speeds.
The drive mechanism for changing the rotation speeds of the first roller 14a and the second roller 14b will be described in detail after the skew correction control has been described.

With reference to FIG. 7, the flow from the start of feeding the paper P1 by the feeding roller 14 to the determination of whether or not to perform the skew correction control will be described by the control unit 19.
In the feeding of the paper P1 by the feeding roller 14, the rotation speed of the first roller 14a and the second roller 14b is set to a constant speed (rotation speed R1 of the first roller 14a = rotation speed R2 of the second roller 14b, in FIG. Is described as R1 = R2).

When the first sheet of paper P1 separated between the feed roller 14 and the separation roller 15 reaches the skew detection unit 21, the first medium detection unit 21a and the second medium detection unit 21a constituting the skew detection unit 21 are formed. Paper P1 is detected by each of 21b (step S1).

When the paper P1 is detected by the first medium detection unit 21a and the second medium detection unit 21b, the detection timing t1 of the paper P1 by the first medium detection unit 21a and the detection timing t2 of the paper P by the second medium detection unit 21b. It is determined whether or not the deviation (t1-t2 = Δt) between them is equal to or greater than a predetermined value (step S2).
When the detection timing deviation Δt is less than a predetermined threshold value (NO in step S2), it is determined that skew has not occurred, skew correction control is not performed, and feeding is continued. When the deviation Δt of the detection timing is equal to or greater than a predetermined threshold value (YES in step S2), skew correction control for correcting the skew of the paper P1 is performed.
The skew correction control executed by the control unit 19 will be described with reference to FIG.

First, in step S11, it is determined whether the value of the deviation Δt is larger or smaller than 0.
When Δt <0, that is, Δt is negative, the detection timing t1 of the paper P1 by the first medium detection unit 21a is early, and as shown in FIG. 6, the + X direction side of the paper P is the upstream side in the medium feeding direction. It is considered that the paper is skewed so that the -X direction side is delayed.
In such a case, the rotation speed R2 of the second roller 14b is made faster than the rotation speed R1 of the first roller 14a (step S12). That is, the rotation speed R1 <rotation speed R2 (described as R1 <R2 in FIG. 8).
As a result, the delayed paper P in the −X direction can be fed so as to catch up with the + X direction side.

The driving of the first roller 14a and the second roller 14b in the state of the rotation speed R1 <rotation speed R2 is performed until the deviation Δt is eliminated. The drive time M of the first roller 14a and the second roller 14b in the state of the rotation speed R1 <the rotation speed R2 until the deviation Δt is eliminated can be obtained by Δt / [R1-R2].
In step S13, it is determined whether or not the vehicle is driven in the state of rotation speed R1 <rotation speed R2 until the deviation Δt is eliminated, and if NO in step S13, the process returns to step S12. If YES is determined in step S13, the skew correction control is terminated, that is, the normal feeding, that is, the rotation speeds of the first roller 14a and the second roller 14b are returned to a constant speed (rotational speed R1 = rotation speed R2).

Returning to step S11, when Δt> 0, that is, when Δt is positive, the detection timing t2 is earlier than the detection timing t1, and contrary to the state of FIG. 6, the −X direction side of the paper P1 is the medium feeding direction. It is considered that it is in a state of being skewed so as to proceed to the upstream side of the above and delay the + X direction side.
In such a case, the rotation speed R1 of the first roller is made faster than the rotation speed R2 of the second roller (step S14). That is, the rotation speed R1> the rotation speed R2 (described as R1> R2 in FIG. 8).
As a result, the delayed paper P can be fed so that the + X direction side can catch up with the −X direction side.

The driving of the first roller 14a and the second roller 14b in the state of the rotation speed R1> the rotation speed R2 is performed until the deviation Δt is eliminated. The drive time M of the first roller 14a and the second roller 14b in the state of the rotation speed R1> the rotation speed R2 until the deviation Δt is eliminated can be obtained by Δt / [R1-R2].
In step S15, it is determined whether or not the vehicle is driven in the state of rotation speed R1> rotation speed R2 until the deviation Δt is eliminated, and if NO in step S15, the process returns to step S14. If YES is determined in step S15, the skew correction control is terminated, that is, the normal feeding, that is, the rotation speeds of the first roller 14a and the second roller 14b are returned to a constant speed (rotational speed R1 = rotation speed R2).

When the control unit 19 executes skew correction control and makes a difference in the rotation speeds of the first roller 14a and the second roller 14b, when the control unit 19 stops one of the first roller 14a and the second roller 14b. good. For example, when the rotation speed R1 <rotation speed R2, only the second roller 14b is driven and the first roller 14a is stopped. When the rotation speed R1> the rotation speed R2, only the first roller 14a is driven to stop the second roller 14b.

This facilitates control by the control unit 19 to make a difference between the rotation speed R1 of the first roller 14a and the rotation speed R2 of the second roller 14b.
Further, for example, in FIG. 6, since the first roller 14a on the side where the paper tip is advanced (+ X direction side) is stopped, the side where the paper tip is delayed (-X direction side) is set with a short feeding distance. It is possible to catch up with the advancing side (+ X direction side). Therefore, the skew correction control can be efficiently performed.
Of course, the rotation speed R1 and the rotation speed R2 may be different while driving both the first roller 14a and the second roller 14b.

In FIG. 8, a case where the skew of the paper P1 is corrected by the feeding roller 14 (the first roller 14a and the second roller 14b) based on the skew amount of the paper P1 detected by the skew detecting unit 21 has been described.
When the next and subsequent sheets P2, P3 ... Are fed after the sheet P1, the skew detection unit 21 detects the skew for each sheet of the sheets P2, P3 ... Based on this, skew correction control can be performed on each paper.

Further, for example, the skew of the first sheet P1 is detected by the skew detection unit 21, and the next and subsequent sheets P2, P3 ... Are skewed from the start of feeding based on the skew detection result of the sheet P1. Correction control can also be performed. This makes it possible to improve the image reading throughput.
In addition, when performing skew correction control for papers P2, P3 ... From the start of feeding based on the skew detection result of the paper P1, either the first roller 14a or the second roller 14b is stopped. Therefore, when the rotations of the first roller 14a and the second roller 14b have different speeds, it can be said that the feeding start timing by the first roller 14a and the feeding start timing by the second roller 14b are staggered.

As described above, in the skew correction control of the present embodiment, the skew of the paper P can be corrected by the feeding roller 14 (feeding unit) provided on the most upstream side of the medium transport path. That is, the skew of the paper P can be corrected at an early stage after the start of feeding from the medium mounting unit 11. Therefore, the skew of the paper P can be efficiently corrected.
Further, it is not necessary to secure a wide path width of the medium transport path in anticipation of the skew of the paper P, and it is possible to avoid an increase in the size of the apparatus.

Further, when the paper P is nipped into both the feed roller 14 and the transport roller pair 16 which is the transport portion on the downstream side of the feed roller 14, the paper P is placed at two locations upstream and downstream in the medium transport direction. Since it is nipped, it is difficult to rotate the paper P so as to correct the skew.
In the present embodiment, after the paper P is started by the feed roller 14, the first roller is reached until the tip of the paper P reaches the transport position by the transport roller pair 16 which is the transport portion on the downstream side of the feed roller 14. By making a difference between the rotation speed R1 of the 14a and the rotation speed R2 of the second roller 14b, the paper P can be rotated to correct the skew, so that the skew correction control can be effectively performed.

Further, in the present embodiment, the skew detection unit 21 is provided on the immediate downstream side of the feed roller 14, that is, between the feed roller 14 and the reading unit 20, and is the most upstream of the transport units for transporting paper. Since it is arranged on the upstream side of the transport roller pair 16 provided on the side, the skew correction control is performed on the paper P1 based on the skew amount in the paper P1 (first medium) detected by the skew detection unit 21. Can be configured to be feasible.

It was determined that the skew of the paper P did not occur at the detection position by the skew detection unit 21, or the skew was small and the skew correction was not necessary. However, after that, the paper tip was niped by the transport roller pair 16. At the time when the image is read by the reading unit 20, the skew may be large.
For example, in FIG. 3, the second detection unit 23 provided on the downstream side of the transport roller pair 16 and the third detection unit 24 provided on the downstream side of the discharge roller pair 17 are provided with a function as a “skew detection unit”. For example, a skew that was not detected at the position of the skew detection unit 21 can be detected. Further, from the reading information in the reading unit 20, it may be possible to detect that the tip of the paper has entered the reading unit 20 at an angle.

For example, the detection timings of both ends of the paper P1 detected by the reading unit 20 in the width direction (X-axis direction), that is, the + X side end portion and the −X side end portion, are set as the detection timing t1 and the detection timing t2. When there is a deviation Δt of a predetermined value or more between the detection timing t1 and the detection timing t2, it can be determined that skew has occurred.

When it is determined that the skew of the paper P1 is not detected at the detection position by the skew detection unit 21, but the skew of the paper P1 is detected on the downstream side of the detection position by the skew detection unit 21, for example, the reading unit 20. On the other hand, based on the skew detection result by the reading unit 20 of the paper P1, the skew correction control can be executed for the next and subsequent papers P2, P3 ....

The “skew detection unit” can be provided at a position other than the position of the skew detection unit 21 of the present embodiment. For example, a "skew detection unit" can be provided on the upstream side of the feeding roller 14. In this case, as the "skew detection unit", for example, a sensor based on the same or similar principle as the sensor capable of detecting two-dimensional (planar) movement used in a computer mouse can be used.
Even when the "skew detection unit" is provided on the upstream side of the feeding roller 14, the skew of the paper P1 fed by the feeding roller 14 is detected at an early stage and the paper P1 is detected as in the present embodiment. It is possible to correct the skew.

Further, as described above, in addition to the second detection unit 23 or the third detection unit 24, the reading unit 20 can also be used as the “skew detection unit”. That is, the reading unit 20 can be configured to also serve as a “skew detection unit”. In this case, when the skew is detected on the first sheet of paper P1, the skew detection result of the sheet P1 is fed back, and the skew correction control is executed from the start of feeding to the next and subsequent sheets P2, P3 ... It can be configured.
By causing the reading unit 20 to also serve as the “skew detection unit”, the number of parts can be reduced and the manufacturing cost can be reduced.

■■■ About the drive mechanism of the first roller and the second roller ■■■
Hereinafter, the drive mechanism of the first roller 14a and the second roller 14b will be described.
As described above, the first roller 14a and the second roller 14b constituting the feeding roller 14 have the rotational speeds of the first roller 14a when the control unit 19 executes the "skew correction control" described above. It is driven so as to make a difference between the rotation speeds R2 of R1 and the second roller 14b. Further, in the case of performing normal paper feeding without performing "skew correction control", the first roller 14a and the second roller 14b are rotationally driven at a constant speed.
In order to facilitate switching between a drive that gives a speed difference between the first roller 14a and the second roller 14b and a drive that makes the speed constant, the first roller 14a and the second roller 14b have the following drive mechanism 30. I have.

The drive mechanism 30 shown in FIGS. 9 and 10 includes a first drive source 31 and a second drive source 32 for driving the second roller 14b, and first drives the drive source for driving the first roller 14a. A switching mechanism 33 for switching between the source 31 and the second drive source 32 is provided.
The operation of the switching mechanism 33 is configured to be controllable by the control unit 19.

Then, when the control unit 19 executes the "skew correction control", the switching mechanism 33 is set to the first state in which the first roller 14a is driven by the first drive source 31, and the "skew correction control" is executed. If not, the switching mechanism 33 is set to the second state in which the first roller 14a is driven by the second drive source 32.

More specifically, as shown in FIGS. 9 and 10, the drive mechanism 30 has a first rotation shaft 34 to which the first roller 14a is fixed and is rotated by receiving power from the first drive source 31, and a first rotation shaft 34. It is provided on the same axis as the rotating shaft 34, has a second roller 14b fixed to it, and has a second rotating shaft 35 that rotates by receiving power from a second drive source 32.
In the present embodiment, as shown in FIG. 10, the second rotating shaft 35 is provided so as to penetrate the inside of the first rotating shaft 34. The second rotating shaft 35 penetrates the inside of the first rotating shaft 34 so as to be rotatable relative to the first rotating shaft 34.

A first gear 36 is provided at the end of the first rotating shaft 34 on the + X direction side. In the present embodiment, the first gear 36 is provided integrally with the first rotating shaft 34. The first gear 36 is engaged with the first transmission gear 37. The first transmission gear 37 is a gear that rotates by receiving power from the first drive source 31 via a power transmission mechanism (not shown). The first transmission gear 37 is provided with a one-way clutch 41.
The one-way clutch 41 receives power from a rotating shaft 42 driven by the first drive source 31. The one-way clutch 41 is provided with the first transmission gear 37 only when the rotary shaft 42 is driven in the direction in which the first roller 14a rotates in the normal direction (rotational direction when feeding paper: the direction of arrow a in FIG. 9). It is configured as a clutch that transmits the rotational torque of the rotary shaft 42.

A second gear 38 is provided at the end of the second rotating shaft 35 on the −X direction side. The second gear 38 is engaged with the second transmission gear 39. The second transmission gear 39 is a gear that rotates by receiving power from the second drive source 32 via a power transmission mechanism (not shown). The second transmission gear 39 is fixedly provided on the rotating shaft 44. The rotary shaft 44 receives rotational torque from the second drive source 32. A one-way clutch is not provided between the rotary shaft 44 and the second transmission gear 39.

In the present embodiment, the switching mechanism 33 is configured to include an electromagnetic clutch 40. In FIGS. 9 and 10, the electromagnetic clutch 40 includes a first member 40a provided at the end of the second rotation shaft 35 on the + X direction side, and a second member 40b fixed to the first rotation shaft 34. It is composed of.
In the electromagnetic clutch 40, in the non-excited state in the present embodiment, as shown in FIG. 10, the first member 40a and the second member 40b are integrated, and the first member 40a and the second member 40b rotate integrally. It is a configuration to do. Further, in the excited state, the first member 40a moves in the + X direction side, a gap is formed between the first member 40a and the second member 40b (not shown), and the first member 40a and the second member 40b are formed. , Each can rotate independently without being affected by the other party.

More specifically, the first member 40a is displaced in the X direction by switching between excitation and non-excitation of the electromagnetic clutch 40, and a concave groove 40c for receiving the key member 43 provided on the second rotation shaft 35 is formed. By inserting the key member 43 into the concave groove 40c in this way, the first member 40a always rotates when the second rotating shaft 35 rotates. However, the concave groove 40c, that is, the first member 40a is allowed to move in the X-axis direction with respect to the key member 43.
In the non-excited state in which the first member 40a and the second member 40b of the electromagnetic clutch 40 are integrated, the first rotating shaft 34 and the second rotating shaft 35 are connected via the electromagnetic clutch 40, whereby the first member 40a and the second member 40b are connected via the electromagnetic clutch 40. The first roller 14a and the second roller 14b are in a state of rotating in perfect synchronization. That is, the second state can be obtained in which the first rotating shaft 34 and the second rotating shaft 35 are connected and integrally rotated by a common second drive source 32.

When the electromagnetic clutch 40 is put into the non-excitation state, the control unit 19 stops driving the first drive source 31. Here, the first transmission gear 37 also rotates due to the rotation of the first rotating shaft 34, that is, the rotation of the first gear 36 (direction of arrow b in FIG. 9), but since the one-way clutch 41 is provided, the rotating shaft 42 Does not rotate, that is, the first rotating shaft 34 can freely rotate without receiving a rotational load from the first drive source 31 side.

In the excited state in which a gap is formed between the first member 40a and the second member 40b in the electromagnetic clutch 40, the first rotating shaft 34 and the second rotating shaft 35 are separated from each other, whereby the first roller The 14a and the second roller 14b are in a state where they can rotate independently.
That is, the first roller 14a is driven by the first drive source 31, the second roller 14b is driven by the second drive source 32, and the first roller 14a and the second roller 14b are driven by individual drive sources. can do.

In this way, the switching mechanism 33 transmits the first state in which the first rotating shaft 34 and the second rotating shaft 35 are separated and individually rotated, and the transmission of power from the first drive source 31 to the first rotating shaft 34. It is configured to switch between the second state in which the first rotating shaft 34 and the second rotating shaft 35 are connected and integrally rotated while being shut off. The above contents are summarized in Table 1.

With the above configuration, when the control unit 19 executes the "skew correction control", the control for adding a speed difference between the first roller 14a and the second roller 14b, and the control when the "skew correction control" is not executed, the first It is possible to easily switch between the control of driving the 1 roller 14a and the 2nd roller 14b at a constant speed.

<<< Other examples of the drive mechanism of the first roller and the second roller >>>
The first roller 14a and the second roller 14b may be simply driven by individual drive sources.
That is, as shown in FIG. 11, the first drive source 31 for driving the first roller 14a and the second drive source 32 for driving the second roller 14b without providing the electromagnetic clutch 40 (switching mechanism 33) are provided. The control unit 19 can be configured to independently control the first drive source 31 and the second drive source 32. In FIG. 11, the first rotating shaft 34 and the second rotating shaft 35 are not connected to each other and are individually rotatable.
When the first roller 14a and the second roller 14b are rotated at a constant speed, the control unit 19 controls to synchronize the rotation of the first roller 14a with the rotation of the second roller 14b.

In addition, the first roller 14a and the second roller 14b may be driven by one drive source.
In this case, for example, a first power transmission mechanism having a train wheel of gears for transmitting power from one drive source to the first roller 14a and a wheel of gears for transmitting power from the same drive source to the second roller 14b. A second power transmission mechanism having a row is provided, and when the control unit 19 executes skew correction control, the reduction ratio of either the first power transmission mechanism or the second power transmission mechanism gear is changed. , The rotation speed R1 of the first roller 14a and the rotation speed R2 of the second roller 14b can be different.
Either one of the first roller 14a and the second roller 14b may be stopped by disengaging the meshing of a part of the gears of the first power transmission mechanism or the second power transmission mechanism train wheel.

In addition, the present invention is not limited to the above embodiment, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

For example, the medium feeding device 10 described above can be mounted not only on the image reading device but also on other devices. As an example, it can be provided in a recording device that records on the conveyed paper (medium).

1 ... Scanner (image reader), 2 ... Device body, 3 ... Lower unit, 4 ... Upper unit, 5 ... Paper output tray, 6 ... Feed port, 7 ... Operation panel, 8 ... 1st auxiliary paper support, 9 ... 2nd auxiliary paper support, 10 ... Medium feeding device, 11 ... Medium mounting part, 12 ... Edge guide, 13 ... Guide surface, 14 ... Feeding roller (feeding part), 14a ... First roller, 14b ... 2nd roller, 15 ... Separation roller, 15a ... 1st separation roller, 15b ... 2nd separation roller, 16 ... Conveyor roller pair, 17 ... Discharge roller pair, 18 ... Discharge port, 19 ... Control unit, 20 ... Reading unit, 20a ... upper reading sensor, 20b ... lower reading sensor, 21 ... skew detection unit, 22 ... first detection unit, 23 ... second detection unit, 24 ... third detection unit, 30 ... drive mechanism, 31 ... first drive source , 32 ... 2nd drive source, 33 ... switching mechanism, 34 ... 1st rotary shaft, 35 ... 2nd rotary shaft, 36 ... 1st gear, 37 ... 1st transmission gear, 38 ... 2nd gear, 39 ... 2nd Transmission gear, 40 ... electromagnetic clutch, 40a ... first member, 40b ... second member, 40c ... concave groove, 41 ... one-way clutch, 42 ... rotating shaft, 43 ... key member, 44 ... rotating shaft, P ... paper (medium) )

Claims (11)

A processing unit that processes the medium,
A first roller and a second roller provided at intervals in the width direction intersecting the medium feeding direction are provided, and the medium is fed from the medium mounting section on which the medium is placed toward the processing section. With the feeding department,
A skew detection unit that detects the skew of the medium supplied from the feeding unit, and
A control unit that controls the operation of the feeding unit is provided.
The control unit is based on the skew amount in the first medium detected by the skew detection unit, the first medium, and the next and subsequent media fed following the first medium. It is possible to execute skew correction control for correcting the skew by making a difference between the rotation speed of the first roller and the rotation speed of the second roller for at least one of them.
A medium feeding device characterized by that. In the medium feeding device according to claim 1,
The control unit stops either the first roller or the second roller when the skew correction control is executed.
A medium feeding device characterized by that. In the medium feeding device according to claim 1 or 2.
The skew detection unit is arranged on the upstream side of the upstream transport unit provided on the most upstream side of the transport units provided between the feed unit and the processing unit to transport the medium.
A medium feeding device characterized by that. In the medium feeding device according to claim 3,
The skew detection unit is arranged so as to overlap a part of the feeding unit on the downstream side of the position where the feeding unit applies a feeding force to the medium.
A medium feeding device characterized by that. In the medium feeding device according to any one of claims 1 to 4.
The skew detection unit is provided at intervals in the width direction, and includes a first medium detection unit and a second medium detection unit capable of detecting the medium.
A medium feeding device characterized by that. In the medium feeding device according to any one of claims 1 to 5.
The first drive source for driving the first roller and
A second drive source for driving the second roller is provided.
A medium feeding device characterized by that. In the medium feeding device according to any one of claims 1 to 5.
The first drive source and
The second drive source that drives the second roller,
A switching mechanism for switching the drive source for driving the first roller between the first drive source and the second drive source is provided.
The control unit that controls the operation of the switching mechanism is
When executing the skew correction control, the switching mechanism is set to the first state in which the first roller is driven by the first drive source.
When the skew correction control is not executed, the switching mechanism is brought into the second state in which the first roller is driven by the second drive source.
A medium feeding device characterized by that. In the medium feeding device according to claim 7,
A first rotating shaft to which the first roller is fixed and rotated by receiving power from the first drive source,
A second rotating shaft provided on the same axis as the first rotating shaft, to which the second roller is fixed, and which rotates by receiving power from the second drive source, is provided.
The switching mechanism cuts off the first state in which the first rotation shaft and the second rotation shaft are separated and individually rotated, and the transmission of power from the first drive source to the first rotation shaft. , The second state in which the first rotating shaft and the second rotating shaft are connected and integrally rotated is switched.
A medium feeding device characterized by that. In the medium feeding device according to claim 8, the switching mechanism is configured to include an electromagnetic clutch.
A medium feeding device characterized by that. A reader that reads the medium,
The medium feeding device according to any one of claims 1 to 9, further comprising the reading unit as the processing unit.
An image reader characterized by this. In the image reading device according to claim 10, the reading unit also serves as the skew detecting unit.
An image reader characterized by this.

Images