JPH11334941A - Sheet feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeder capable of discharging sheets one by one when sheet double feeding occurs. SOLUTION: When a sheet S is fed, a second upper roller 22 is rotated in a rotational direction opposite to the sheet feeding direction. Accordingly, when the double sheets S are fed overlappingly each other, a flexure of the sheets S is generated. The flexure of the sheets S is detected by a sensor 31 so that the double feeding of the sheets S is detected. When the sensor 31 detects the double feeding of the sheets S, a second lower roller 21 is rotated in its normal rotational direction and the second upper roller 22 is rotated in the opposite rotational direction. As a result, of the overlapping sheets S, the sheet S on the second lower roller 21 side is discharged, and then, the sheet S on the second upper roller 22 side is discharged by switching the rotational direction of the second upper roller 22 to its normal rotational direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus for conveying a sheet-like material (hereinafter, simply referred to as a "sheet") such as a film or paper conveyed by rollers, and more particularly, to detecting a two-sheet feed of a sheet. The present invention relates to a sheet conveying device provided with a two-sheet feed detecting device.

[0002]

2. Description of the Related Art Conventionally, as a two-sheet feed detecting device used in such a sheet conveying device, a sensor capable of detecting a leading end and a trailing end of a sheet in a conveying path of a sheet conveyed by a roller is known. Is used. In such a conventional two-sheet feed detecting device, a pulse generated in synchronization with the rotation of a motor for driving a roller is counted by a counter, and the sensor detects the leading edge of the sheet and then detects the trailing edge of the sheet. By measuring the number of pulses counted by this counter during the time before, the length of the sheet passing through the sensor is measured, and when the measured value of the length of the sheet becomes larger than the preset sheet length Then, it is determined that two sheets have been fed.

[0003]

By the way, in a sheet conveying apparatus provided with such a two-sheet feed detecting device,
It is possible to detect two-sheet feeding, but it is not possible to discharge two-sheet fed sheets one by one.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a sheet conveying apparatus capable of discharging sheets one by one even when two sheets are fed. Aim.

[0005]

According to a first aspect of the present invention, there is provided a sheet conveying apparatus provided with a two-sheet feed detecting device for detecting two-sheet feed of a sheet, wherein the sheet is rotated by driving a first driving means. A first lower roller to be provided, a second lower roller disposed downstream of the first lower roller and rotated by driving of a second driving unit, and a state in which the second lower roller is in contact with the first lower roller. And a first upper roller that rotates in synchronization with the first lower roller, and is disposed in contact with the second lower roller, and rotates when driven by third driving means. A second upper roller, a detection mechanism for detecting that two sheets have been fed in a state where the sheets overlap each other at a contact position between the second lower roller and the second upper roller, and the detection mechanism includes: When the sheet feed of two sheets is detected, the second upper The chromatography La is stopped, or the second
By rotating the sheet in the direction opposite to the sheet conveying direction by the lower roller, only the sheet on the side of the second lower roller among the sheets overlapping each other is contacted by the second lower roller and the second upper roller. After being discharged from the contact position, the second upper roller is rotated in the same direction as the sheet conveying direction by the second lower roller, so that the second upper roller is rotated.
And a control means for discharging the sheet on the upper roller side from the contact position between the second lower roller and the second upper roller.

According to a second aspect of the present invention, there is provided a sheet conveying apparatus provided with a two-sheet feed detecting device for detecting a two-sheet feed of a sheet, wherein the first lower roller is rotated by driving a first driving means. A second lower roller disposed downstream of the first lower roller and rotated by driving of a second driving unit; and a second lower roller disposed in contact with the first lower roller, A first upper roller that rotates in synchronization with the first lower roller; and a first upper roller that is disposed in contact with the second lower roller, and is driven by a third driving unit to rotate the second lower roller. A second upper roller rotatable in the same or opposite direction to the first direction, the first lower roller and the first
The first lower roller and the first upper roller are disposed between a position where the sheet is nipped by the upper roller and a position where the sheet is nipped by the second lower roller and the second upper roller. Detecting means for detecting a change in the distance to a sheet conveyed while being nipped by the second lower roller and the second upper roller after being nipped; and The second lower roller having a driving force weaker than the rotational driving force of the second lower roller.
By rotating the sheet in a direction opposite to the sheet conveying direction by the lower roller, when the sheets are fed in a state of being overlapped with each other, the bending generated in the sheet on the second upper roller side is detected by the detecting means. And when the detecting means detects the two-sheet feeding, the first and second lower rollers and the first upper roller are rotated when the detecting means detects the two-sheet feeding. Stopping the second upper roller, or rotating the second upper roller in a direction opposite to the sheet conveying direction by the second lower roller, so that the sheet on the side of the second lower roller among the sheets that overlap with each other is After the sheet is discharged from the contact position between the lower roller and the second upper roller, the rotation direction of the second upper roller is set to the same direction as the sheet conveying direction by the second lower roller. By switching to the second upper roller side sheet and the second lower roller second
And a control means for discharging the sheet from the contact position with the upper roller.

According to a third aspect of the present invention, in the first or second aspect of the invention, the second upper roller has a length equal to or less than the width of the sheet to be conveyed. .

According to a fourth aspect of the present invention, in the first aspect of the present invention, there is provided a sheet detecting means for detecting a leading edge of a sheet at a stage subsequent to the second lower roller. Are arranged along the width direction of the sheet to be conveyed.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a sheet conveying apparatus according to the present invention.

The sheet conveying apparatus includes a first lower roller 11 that rotates by driving a motor 13, a second lower roller 21 that rotates in synchronization with the first lower roller 11 by driving a motor 23, The first upper roller 12 is disposed in contact with the first lower roller 11, and rotates in synchronization with the first lower roller 11 by driving of the motor 14.
And a second upper roller 22 disposed in contact with the second lower roller 21.
The sheet S is nipped and conveyed between the first upper roller 12 and the second lower roller 21 and the second upper roller 22.

The second upper roller 22 is connected via a shaft 25 to a forward / reversely rotatable torque motor 24. The torque motor 24 drives the second upper roller 22 in the same direction or the opposite direction to the rotation direction of the second lower roller 21 with a driving force smaller than the driving force of the second lower roller 21 by the motor 23. Is applied. The length L of the second upper roller 22 is sufficiently smaller than the width W of the sheet S to be conveyed.

The position where the first lower roller 11 and the first upper roller 12 sandwich the sheet and the second lower roller 21
Between the first lower roller 11 and the first upper roller 12
The sheet S conveyed while being nipped by the second lower roller 21 and the second upper roller 22 after being nipped by
A sensor 31 for detecting a change in the distance to is provided.

FIG. 2 shows that the sensor 31 includes a first lower roller 11, a first upper roller 12, and a second lower roller 2.
FIG. 4 is a schematic side view schematically showing a sheet S conveyed by first and second upper rollers 22;

When the sensor 31 comes into contact with the sheet S, the first lower roller 11 and the first upper roller 1
2 and the second lower roller 21 and the second lower roller 21
And a detector 32 for detecting a change in the distance to the sheet S conveyed while being nipped by the upper roller 22.

The sensor 31 is not limited to a sensor having a mechanical structure provided with the above-described detector 32. For example, the sensor 31 includes a light emitting / receiving element and is reflected by the surface of the sheet S to reach the sheet S. Optical, electrical or acoustic, such as those having a configuration for detecting a change in the distance of the sheet S, and those having a configuration for detecting a change in the distance to the sheet S by emitting ultrasonic waves to the surface of the sheet S Various sensors can be used.

Referring again to FIG. 1, the second lower roller 2
The sheet detection sensor 3 including a light projecting unit 33 and a light receiving unit 34 for detecting the leading end of the sheet
5 are provided along the width direction of the sheet S.

Also, the sheet conveying apparatus has a control unit having a ROM in which an operation program necessary for controlling the apparatus is stored, a ROM in which an operation program necessary for controlling the apparatus is stored, and a CPU for executing a logical operation. 41 are provided.
The motors 13, 14, and 23 and the torque motor 24 are connected to the control unit 41, and the driving of the motors is controlled by the control unit 41. The control unit 41 measures pulses transmitted in synchronization with the rotation of the motors 13, 14, 23 and the torque motor 24.
3, 14, 23 and the number of rotations of the torque motor 24, that is, the sheet S by the rollers 11, 12, 21, and 22
Is being monitored. Further, the sensor 31 and each sheet detection sensor 35 are also connected to the control unit 41, and the detection result is transmitted to the control unit 41.

Next, the sheet S is transported by the sheet conveying device.
Will be described when two sheets are detected to be fed.

In the normal sheet S conveyance state, the sheet S conveyed from the preceding sheet S supply section is the first sheet S.
Lower roller 11 and first upper roller 12
Are held between the lower roller 21 and the second upper roller 22, respectively, and are conveyed in the horizontal direction as indicated by the dashed line in FIG.

At this time, the second upper roller 22 is provided with a driving force from the torque motor 24 in a direction opposite to the driven rotation direction of the second lower roller 21.
This driving force is set smaller than the driving force of the second lower roller 21 by the motor 23, and the second upper roller 2
2 rotates in the driven rotation direction with respect to the second lower roller 21 as the sheet S moves.

On the other hand, when the sheet S is sandwiched between the second lower roller 21 and the second upper roller 22 in a superimposed state, the second upper roller 21 is driven by a torque motor 24. By the force, it rotates in the opposite direction to the driven rotation direction. That is, since a driving force greater than the frictional force between the two sheets S superimposed on each other is applied to the second upper roller 22 by the torque motor 24, the driving force A slip occurs between the sheets S, and the second upper roller 22 rotates in a direction opposite to the driven rotation direction with the slip.

Even in such a state, the two sheets S, which are superimposed on each other, are both moved by the first lower roller 11 and the first upper roller 12 to the second lower roller 21 and the second lower roller 21. 2 is conveyed in the direction of the upper roller 22. The sheet S on the second lower roller 21 side of the two sheets S superimposed on each other is conveyed by the second lower roller 21.

However, the two superimposed states overlap each other.
Sheet S on the second upper roller 22 side of the sheet S
Cannot pass through the pinching position between the second lower roller 21 and the second upper roller 22. Therefore, of the two sheets S superimposed on each other, the second upper roller 22
The sheet S on the side is bent, and as shown by a solid line in FIG. 2, the sheet S curves in a chevron toward the sensor 31, and eventually contacts the detector 32 of the sensor 31.

When the sensor 31 detects that the sheet S has contacted the detector 32 due to its bending,
It is determined that two-sheet feeding of the sheet S has occurred. Then, the sensor 31 sends a signal to a display unit (not shown) via the control unit 41 to display the occurrence of the double-sheet feed.

As described above, the second upper roller 22
Is rotated in a direction opposite to the direction in which the sheet S is conveyed by the second lower roller 21 with a driving force weaker than the rotational driving force of the second lower roller 21, thereby generating a sheet on the second upper roller 22 side. In the case where the configuration in which the bending is detected by the sensor 31 and the two-sheet feeding of the sheets S is employed is adopted, even when the two sheets S are conveyed in a state of being completely superimposed without being shifted from each other, the second method is adopted. This has a specific effect that sheet feed can be reliably detected.

Even after the sensor 31 detects the double feed of the sheet S, the same state as before the sensor 31 detects the double feed of the sheet S is continued. That is, the first lower roller 11, the first upper roller 12, and the second lower roller 21 are rotated in a direction in which the sheet S is conveyed toward the sheet detection sensor 35 (hereinafter, this rotation direction is referred to as “forward rotation”). Direction)), the second upper roller 22 is
Is rotated in the direction in which the sheet is conveyed to the opposite side of the sheet detection sensor 35 (hereinafter, this rotation direction is referred to as “reverse rotation direction”).
In addition, instead of rotating the second upper roller 22 in the reverse rotation direction, the rotation may be stopped.

In this state, of the two sheets S superimposed on each other, the sheet S on the side of the second lower roller 21 is conveyed toward the sheet detection sensor 35 by driving the second lower roller 21. Is done. However, the sheet S on the second upper roller 22 side of the two sheets S superimposed on each other is the second lower roller 21 and the second lower roller 21.
Cannot pass through the pinching position by the upper roller 22, and stops at this position.

By continuing this state, the sheet S on the second lower roller 21 side of the two sheets S superimposed on each other is conveyed toward the sheet detection sensor 35, and the leading end of the sheet S When the sheet reaches the sheet detection sensor 35, the parallelism of the sheet S is detected by the sheet detection sensor 35.

That is, one of the three sheet detection sensors 35 first detects the sheet S
Is detected, the control unit 41 determines a time T required until the sheet detection sensor 35 that has detected the sheet S later among the other two sheet detection sensors 35 detects the sheet S, and this time If T is equal to or greater than a preset value, it is determined that the sheet S has been conveyed in a meandering state. Then, the control unit 41 sends a signal to display means (not shown) to display the occurrence of the meandering, and the first lower roller 11, the first upper roller 12, the second lower roller 21, and the second upper roller 22 Is stopped, and the conveyance of the sheet S is stopped.

When the meandering of the sheet S is not detected, the rear end of the sheet S on the side of the second lower roller 21 of the two sheets S superimposed on each other is the first lower roller 11. The current conveyance state is continued until the sheet passes through the holding position between the sheet and the first upper roller 21. The rear end of the sheet S is a first lower roller 11 and a first upper roller 2
1 after the leading edge of the sheet S is detected by the sheet detection sensor 35,
The rotation speed of the sheet S, that is, the transport distance of the sheet S is
It is performed by measuring with.

The rear end of the sheet S on the side of the second lower roller 21 of the two sheets S superimposed on each other determines the position at which the first lower roller 11 and the first upper roller 21 are nipped. If it passes, the rotation of the first lower roller 11 and the first upper roller 21 is stopped, and the second lower roller 2
The sheet S on the second lower roller 21 side is conveyed among the two sheets S superimposed on each other by only one.

As described above, the rear end of the sheet S on the second lower roller 21 side of the two sheets S superimposed on each other is pinched between the first lower roller 11 and the first upper roller 21. After passing through the position, the rotation of the first lower roller 11 and the first upper roller 21 is stopped because the first lower roller 11, the first upper roller 12, and the second
This is to prevent the sheet S on the second upper roller 22 side from being excessively bent at a position between the lower roller 21 and the second upper roller 22. However, when there is a sufficient space between the first lower roller 11 and the first upper roller 12 and the second lower roller 21 and the second upper roller 22,
The first lower roller 11 and the first upper roller 21 may be continuously rotated.

By continuing this state, the rear end of the sheet S on the side of the second lower roller 21 of the two sheets S superimposed on each other is brought into contact with the second lower roller 21 and the second lower roller 21.
When the second upper roller 22 has passed the pinching position with the upper roller 22, the rotation of the second upper roller 22 is switched from the reverse rotation direction to the normal rotation direction. As a result, the sheet S on the second upper roller 22 side of the two sheets S superimposed on each other passes through the sandwiching position between the second lower roller 21 and the second upper roller 22, and the sheet is detected. It is transported toward the sensor 35.

Then, when it is confirmed that the curved shape of the upper sheet S is alleviated with the conveyance of the upper sheet S and the detector 32 of the sensor 31 does not detect the sheet S, the first lower roller 11 By rotating the first upper roller 12, the sheet S is transported in a normal transport state. In this state, the rotation of the second upper roller 22 is switched again from the normal rotation direction to the reverse rotation direction, and a case is prepared in which two more sheets S are further fed.

The length L of the second upper roller 22 is preferably smaller than the width W of the sheet S to be conveyed. When the length L of the second upper roller 22 is larger than the width W of the sheet S to be conveyed, the second upper roller 22 and the second lower roller 21 are in direct contact on both sides of the sheet S. Will be. In this case, due to the frictional force between the second upper roller 22 and the second lower roller 21, the second upper roller 22 is driven by the second lower roller 21, and the sheet S is stopped. This is because it is not possible to cause slippage necessary for detecting the two-sheet feed on the sheet S.

In the above embodiment, the sheet S
As a detection mechanism for selecting the two-sheet feed, a configuration in which the deflection generated in the sheet S is detected by the sensor 31 that detects a change in the distance to the sheet S and the two-sheet feed is detected is employed. However, it is also possible to employ other two-sheet feed detecting means.

[0037]

According to the first aspect of the present invention, by stopping the second upper roller or rotating the second upper roller in a direction opposite to the sheet conveying direction by the second lower roller,
After discharging only the sheet on the second lower roller side among the sheets overlapping each other from the contact position between the second lower roller and the second upper roller, the second upper roller is driven by the second lower roller. By rotating the sheet in the same direction as the sheet conveying direction, the sheet on the second upper roller side is discharged from the contact position between the second lower roller and the second upper roller. After detecting the sheet feed,
These sheets can be discharged one by one.

According to the second aspect of the present invention, the second upper roller is driven in a direction opposite to the sheet conveying direction by the second lower roller with a driving force weaker than the rotational driving force of the second lower roller. By rotating the sheet, the detecting means detects the bending generated in the sheet on the second upper roller side to detect the two-sheet feeding, so that the two sheets are completely overlapped without shifting each other. Even when the sheet is conveyed in the state, it is possible to reliably detect the double sheet feeding.

When the two-sheet feed is detected, the second upper roller is stopped or rotated in the direction opposite to the sheet conveying direction by the second lower roller, so that the sheets overlap each other. After the sheet on the second lower roller side is discharged from the contact position between the second lower roller and the second upper roller, the rotation direction of the second upper roller is changed by the second lower roller. By switching to the same direction as the transport direction, the sheet on the second upper roller side is discharged from the contact position between the second lower roller and the second upper roller. After detection, these sheets can be discharged one by one.

According to the third aspect of the present invention, since the second upper roller has a length equal to or less than the width of the sheet to be conveyed, the distance between the second upper roller and the second lower roller is reduced. The second upper roller is driven by the second lower roller due to the frictional force, so that the sheet S cannot be stopped, and it is impossible to cause a slip required for detecting two-sheet feeding on the sheet. Can be prevented.

According to the fourth aspect of the present invention, a plurality of sheet detecting means for detecting the leading end of the sheet are provided downstream of the second lower roller along the width direction of the sheet to be conveyed. Because of the arrangement, based on the time difference when detecting the leading edge of the sheet by these sheet detection means,
The meandering of the sheet can be detected.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a sheet conveying apparatus according to the present invention.

FIG. 2 is a schematic side view schematically showing a sensor 31 together with a sheet S conveyed by a first lower roller 11, a first upper roller 12, a second lower roller 21, and a second upper roller 22. is there.

[Explanation of symbols]

 Reference Signs List 11 first lower roller 12 first upper roller 13 motor 14 motor 21 second lower roller 22 second upper roller 23 motor 24 torque motor 31 sensor 32 detector 35 sheet detection sensor 41 control unit S sheet

Claims (4)

[Claims] 1. A sheet conveying device provided with a two-sheet feed detecting device for detecting two-sheet feeding of a sheet, comprising: a first lower roller rotated by driving a first driving means; A second lower roller disposed downstream of the roller and rotated by driving of a second driving unit; and a second lower roller disposed in contact with the first lower roller and synchronized with the first lower roller. A first upper roller that rotates while being in contact with the second lower roller;
A second upper roller that is rotated by the drive of the second driving unit, and detecting that two sheets have been fed in a state where the sheets overlap each other at a contact position between the second lower roller and the second upper roller. A detection mechanism, when the detection mechanism detects two-sheet feeding, by stopping the second upper roller or rotating the second upper roller in a direction opposite to the sheet conveying direction by the second lower roller. And, of the sheets overlapping each other, only the sheet on the second lower roller side is connected to the second lower roller and the second lower roller.
After being discharged from the contact position with the upper roller of the second
Is rotated in the same direction as the sheet conveying direction by the second lower roller, so that the sheet on the second upper roller side is brought into contact with the second lower roller and the second upper roller. And a control unit for discharging the sheet from a position. 2. A sheet conveying device provided with a two-sheet feed detecting device for detecting two-sheet feeding of a sheet, comprising: a first lower roller rotated by driving a first driving means; A second lower roller disposed downstream of the roller and rotated by driving of a second driving unit; and a second lower roller disposed in contact with the first lower roller and synchronized with the first lower roller. A first upper roller that rotates while being in contact with the second lower roller;
A second upper roller rotatable in the same direction or a reverse direction as the rotation direction of the second lower roller by driving of the driving means, and a sheet nipping position between the first lower roller and the first upper roller. And the second lower roller and the second upper roller are disposed between a position where the sheet is nipped and the second upper roller is nipped by the second roller after being nipped by the first lower roller and the first upper roller. Detecting means for detecting a change in the distance to a sheet conveyed while being nipped by the lower roller and the second upper roller; and when the sheet is conveyed, the second upper roller is connected to the second lower roller. By rotating the sheet in a direction opposite to the conveying direction of the sheet by the second lower roller with a driving force weaker than the rotational driving force, the second upper roller is rotated when the two sheets are fed in a state of being overlapped with each other. Detecting the deflection of the sheet on the roller side by the detection means to detect the two-sheet feeding, and detecting the first and second lower portions when the detecting means detects the two-sheet feeding. In a state where the roller and the first upper roller are rotated,
By stopping the second upper roller or rotating the sheet in the direction opposite to the sheet conveying direction by the second lower roller, the sheet on the side of the second lower roller among the sheets overlapping each other is moved to the second position. After discharging from the contact position between the lower roller and the second upper roller, by switching the rotation direction of the second upper roller to the same direction as the sheet conveying direction by the second lower roller, Control means for discharging a sheet on a second upper roller side from a contact position between the second lower roller and the second upper roller. 3. The sheet conveying device according to claim 1, wherein the second upper roller has a length equal to or less than a width of a sheet to be conveyed. 4. The sheet conveying apparatus according to claim 1, wherein a sheet detecting unit for detecting a leading end of the sheet is to be conveyed downstream of the second lower roller. A sheet conveying device in which a plurality of sheets are arranged along the width direction of the sheet.