Paper sheet conveying apparatus

Abstract

A paper sheet conveying apparatus has a conveying belt which moves and conveys a paper sheet, a detection sensor which detects the amount of displacement of the conveying belt from a reference position while moving, and a control device which drives the conveying belt at a low speed when a new device is installed as a conveying belt and initially started up, and after the low-speed driving, variably controls the speed of the conveying belt based on the amount of displacement of the conveying belt detected by the detection sensor.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2005-269985, filed Sep. 16, 2005, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a paper sheet conveying apparatus used in a paper money processing machine, for example.

2. Description of the Related Art

A paper money processing machine sets paper money in a take-out unit, takes out and conveys the set paper money one by one through a conveying belt, judges the kind, front/back, true/false, and normal/damaged of the conveyed paper money by a judgment device, classifies the paper money according to the results of judgment, and stacks the paper money in a plurality of stacking box.

A paper money processing machine, particularly, a large-scale machine processing at middle and high speeds uses a conveying motor to drive a conveying belt at middle and high speeds. A belt with a relatively low expansion rate (difficult to expand) is used as a conveying belt, and stretched over with a strong tension, in order to withstand such driving at middle and high speeds.

However, a conveying belt is stretched over with such a strong tension, the belt will be accustomed to being tightly stretched when assembling the machine or replacing the belt, or after installing a new conveying belt.

If a machine operation speed is increased to a normal operation speed immediately after power is turned on, the conveying belt may move zigzag, come off, or break.

Therefore, in a conventional machine, a release motor is provided in addition to a conveying motor. When assembling the machine or replacing the belt, the operator opens the machine door, and uses the release motor to move the conveying belt at a low speed as a test run. By this test run, the belt is familiarized to the surrounding conditions, and prevented from getting habits. (Refer to Jpn. Pat. Appln. KOKAI Publication No. 2003-276904, for example.)

However, in the past, judgment on whether a conveying belt is familiarized depends on the sense and experience of a machine assembling or maintenance engineer. The judgment is not always correct. If misjudgment occurs, a conveying belt is driven before being familiarized with the conveying rollers, causing meandering, coming off, or breaking. This is a problem, particularly in a middle/high speed paper money processing machine.

Further, the work to familiarize a conveying belt is dangerous, because a conveying mechanism is operated by opening the machine door.

A conveying belt may also be accustomed to being expanded, when an ambient operating temperature is low, or when the belt has not been used for a certain period, as well as immediately after assembling the machine, or replacing the belt. In such a case, a test run is often not performed at startup of operation, and the belt shifts or comes out, causing a paper jam.

When a paper jam occurs, a jammed paper sheet is removed and the conveying belt is re-driven, but in this case, sometimes the belt may be going to come off. If the conveying belt is re-driven in such a condition, a secondary jam may occur causing a serious, trouble such as, breaking of the belt.

Further, to remove a jammed paper sheet, the operator opens the machine door and moves the conveying belt by using the release motor. This is very dangerous.

Some types of machine turn off power when the door is opened, and permit the operator to remove a jammed paper sheet by operating a conveying system by a hand knob. However, when the conveying system is long and includes a plurality of module, there arises a problem that the operator does not easily clear a paper jam.

BRIEF SUMMARY OF THE INVENTION

The present invention has been made under the above circumstances. Accordingly, it is an object of the invention to provide a paper sheet conveying apparatus, which is configured to make automatic, safe and quantitative adjustment to familiarize a conveying belt.

According to a first aspect of the invention, there is provided a paper sheet conveying apparatus comprising a conveying belt which moves and conveys a paper sheet; a detection device which detects the amount of displacement of the conveying belt from a reference position while moving; and a control device which drives the conveying belt at a low speed when a new device is installed as a conveying belt and initially started up, and after the low-speed driving, variably controls the speed of the conveying belt based on the amount of displacement detected by the detection device.

According to a second aspect of the invention, there is provided a paper sheet conveying apparatus comprising a conveying belt which moves and conveys a paper sheet; a detection device which detects the amount of displacement of the conveying belt from a reference position while moving; a temperature detection device which detects an ambient operating temperature of the conveying belt; and a control device which drives the conveying belt at a low speed when the temperature of the conveying belt at startup of driving detected by the temperature detection device is lower than a reference temperature, and after the low-speed driving, controls the speed of the conveying belt based on the amount of displacement of the conveying belt detected by the detection device.

According to a third aspect of the invention, there is provided a paper sheet conveying apparatus comprising a conveying belt which moves and conveys a paper sheet; a detection device which detects the amount of displacement of the conveying belt from a reference position while moving; a judgment device which judges whether the conveying belt has been stopped for over a certain period at startup of driving the conveying belt;.and a control device which drives the conveying belt at a low speed when the judgment device judges the conveying belt to have been stopped for over a certain period, and after the low-speed driving, controls the speed of the conveying belt based on the amount of displacement of the conveying belt detected by the detection device.

According to a fourth aspect of the invention, there is provided a paper sheet conveying apparatus comprising a conveying belt which moves and conveys a paper sheet; a jam detection device which detects a jam of a paper sheet conveyed by the conveying belt; a detection device which detects the amount of displacement of the conveying belt from a reference position after the paper jam is cleared; a judgment device which judges whether the conveying belt is to be driven based on the amount of displacement of a paper sheet detected by the detection device; and a control device which drives the conveying belt at a low speed when the judgment device judges the conveying belt to be driven, and after the low-speed driving, variably controls the speed of the conveying belt based on the amount of displacement detected by the detection. device.

According to a further aspect of the invention, it is possible to make automatic and quantitative adjustment to familiarize a conveying device, at startup of the first drive after a new conveying device is installed, thereby preventing a conveying device from meandering, coming out, and breaking.

Besides, after a paper jam is cleared, it is possible to determine whether a conveying device is to be driven, thereby preventing a secondary paper jam.

Moreover, it is possible to notify a replacement period before a conveying device reaches the end of life, thereby preventing a paper jam.

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is an external perspective view of a paper sheet processing apparatus according to a first embodiment of the invention;

FIG. 2 is a plane view showing a conveying belt in the paper sheet processing apparatus of FIG. 1;

FIG. 3 is a front view showing the conveying belt of FIG. 2;

FIGS. 4A to 4C are graphs, each showing the amount of displacement of the conveying belt of FIG. 2;

FIGS. 5A to 5C are graphs, each showing the amount of displacement of the conveying belt of FIG. 2;

FIG. 6 is a block diagram showing a drive control system of the conveying belt of FIG. 2;

FIGS. 7A to 7C are graphs, each showing the amount of displacement of the conveying belt of FIG. 6;

FIGS. 8A to 8C are graphs, each showing a rotation speed of a conveying motor of the conveying belt of FIG. 6;

FIGS. 9A to 9C are graphs, each showing changes in an ambient operating temperature detected by a temperature sensor of FIG. 6;

FIGS. 10A to 10C are graphs, each showing a rotation speed of a conveying motor variable based on the changes in the ambient operating temperatures of FIG. 9;

FIG. 11 is a block diagram showing a drive control system of a conveying belt according to a second embodiment of the invention;

FIGS. 12A to 12C are graphs, each showing drive states of the conveying belt of FIG. 11;

FIGS. 13A to 13C are graphs, each showing the amount of displacement of the conveying belt of FIG. 11;

FIG. 14 is a block diagram showing a drive control system of a conveying belt according to a third embodiment of the invention;

FIG. 15 is a plane view showing a state that the conveying belt of FIG. 14 comes out;

FIGS. 16A to 16C are graphs, each showing changes in a rotation speed of a conveying motor of FIG. 14; and

FIGS. 17A to 17C are graphs, each showing the amount of displacement of the conveying belt of FIG. 14.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, preferred embodiments of the invention will be explained in detail with reference of the accompanying drawings.

FIG. 1 is a schematic diagram showing a paper sheet processing apparatus according to an embodiment of the invention.

The paper sheet processing apparatus has a main body 100. The front side of the main body 100 can be opened and closed by a door 100a. A take-out unit 1 is provided on one side within the main body 100. The take-out unit 1 is provided with a take-out rotor 8 to take out a stack of paper sheet P one by one sequentially from the top. The paper sheet P taken out by the take-out rotor 8 is held and conveyed by a conveying device at a constant speed. The conveying device 2 is provided with a processor 3, which performs various processing for the paper sheet P. The take-out side of the processor 3 is branched into first and second conveying paths 9 and 11. At the branching point, a first sorting gate 4 is provided to sort the paper sheet P to the first and second conveying paths 9 and 11. The take-out side of the first conveying path 9 is branched into third and fourth 13 and 14. At the branching point, a second sorting gate 12 is provided. The third and fourth conveying paths 13 and 14 are connected to first and second stacking units 5a and 5b, and the second conveying path 11 is connected to a stacking unit 6 for ejection.

In the first conveying path 9, an optical sensor 15 is provided to count the number of passing paper sheets. Each time the optical sensor 15 detects 100 sheets, the second sorting gate 12 is operated to sort the paper sheets to the direction of the first or second stacking unit 5a or 5b.

In the above configuration, the paper sheet P taken out from the take-out unit 1 is conveyed to the processor 3 by the conveying device 2, and processed there. Based on the processed information, the first sorting gate 4 is operated to sort the paper sheet P to the first or second conveying path 9 or 11. The paper sheet sorted to the second conveying path 11 is stacked in the stacking unit 6 for ejection. The paper sheet P sorted to the second conveying path 9 is set to the first stacking unit 5a through the third conveying path 13, and stacked there. When 100 sheets are stacked in the first stacking unit 5a, the second sorting gate is operated to send the paper sheet P to the second stacking unit 5b through the fourth conveying path 14, and stacked there. The paper sheets P stacked in the first and second stacking units 5a and 5b are stacked again as a bundle. Likewise, the paper sheet stacked in the stacking unit 6 for ejection is stacked as a bundle.

FIG. 2 is a plane view showing the above-mentioned conveying device 2. FIG. 3 is a front view of the conveying device.

The conveying device 2 has a pair of conveying belts 21a and 21b provided parallel with a predetermined space. The conveying belts 21a and 21b are extended over conveying rollers 22. The conveying roller 22 is rotatably fixed to a support shaft 23. The support shaft 23 is fixed to a unit frame 24. The conveying roller 22 is driven by a conveying motor 25. The conveying belts 21a and 21b are moved by the rotation of the motor.

In the vicinity of the conveying belts 21a and 21b, a detection sensor 27 is provided as a detection device to detect the amount of displacement of the belts while moving. The detection sensor 27 detects the amount of displacement of the conveying belts 21a and 21b while moving, as shown in FIG. 4 and FIG. 5.

FIG. 4A shows the state that the amount of displacement of one conveying belt 21a is large. FIG. 4B shows the state that the amount of displacement of the conveying belt 21a is improved. FIG. 4C shows the state that the amount of displacement of the conveying belt 21a falls within given limits and the belt is stabilized.

FIG. 5A shows the state that the amount of displacement of the other conveying belt 21b is large. FIG. 5B shows the state that the amount of displacement of the conveying belt 21b is improved. FIG. 5C shows the state that the amount of displacement of the conveying belt 21b falls within given limits and the belt is stabilized.

FIG. 6 shows the drive control system of the conveying system configured as described above.

The detection sensor 27 is connected to a control device 29, as a control device/a judgment device, through a transmission circuit. The control device 29 is connected to the conveying motor 25 of the conveying belt 21a/21b, and is connected to first and second notify units as first and second notify devices, through the control circuit. The control device 29 is also connected to a temperature sensor 28 as a temperature detection device to detect an ambient operating temperature of the conveying system, and is connected to a low-speed operation switch 26. The first notify device 30a notifies an estimated time that the amount of displacement of the conveying belts 21a and 21b falls within given limits and the belt is stabilized. The second notify device 30b notifies the states that the amount of displacement of the conveying belts 21a and 21b detected by the detection sensor 27, or the amount of displacement of the conveying belts 21a and 21b, is over a predetermined value, improved, and falls within given limits, respectively. The first and second notify devices 30a and 30b make notification by displaying letters or by sounds.

After assembling the apparatus or after maintenance/replacement of the conveying belt, or when operating at a low temperature or when restarting after stopping the conveying belt for a certain period, the control device 29 operates the conveying motor 25 at a low speed for a certain time. After this low-speed operation, the control device variably controls the speeds of the conveying motor 25 and the conveying belts 21a and 21b according to the amount of displacement of the conveying belt 21 detected by the detection sensor 27, as described later in detail.

Explanation will known be given on the operation of the conveying motor 25 after assembling the apparatus or after maintenance/replacement of the conveying belt, or after installing a new conveying belt.

First, close the door 10a, and manually depress the low-speed operation switch 26. The control device 29 operates the conveying motor 25 at a low speed as a trial run, and gradually increases the speed by monitoring the positions, displacement and meandering of the conveying belts 21a and 21b through the detection sensor 27, and makes automatic and quantitative adjustment to familiarize the conveying belt to the conveying system.

Namely, after the conveying belts 21a and 21b are moved at a low speed by the conveying motor 25, the amount of displacement of the conveying belts 21a and 21b is detected by the detection sensor 27. In this time, when the amount of displacement of the conveying belt 21b is large, for example, as shown in FIG. 7A, the control device 29 controls the speed of the conveying motor 25 to a low speed, as shown in FIG. 8A. As the amount of displacement of the conveying belt 21b is improved as shown in FIG. 7B by this low-speed operation, the speed of the conveying motor 25 is increased as shown in FIG. 8B. When the amount of displacement of the conveying belt 21b falls within given limits and the conveying belt is stabilized by this low-speed operation as shown in FIG. 7C, the speed of the conveying motor 25 is increased to a normal operation speed as shown in FIG. 8C.

While the conveying belts 21a and 21b are moving, the first notify device 30a notifies an estimated time that the amount of displacement of the belts 21a and 21b falls within given limits. This estimated time is determined based on the past data and the changes in the amount of displacement of the conveying belts 21a and 21b detected by the detection sensor 27.

Further, the second notify device 30b notifies the amount of displacement of the conveying belts 21a and 21b at the present time, for example, the states that the amount of displacement of the conveying belts 21a and 21b is over a predetermined value, improved, and falls within given limits.

Since the adjustment to familiarize the conveying belts 21a and 21b to the conveying system is made automatically and quantitatively as described above, the belts can be securely familiarized with less variations, compared with the conventional adjustment by the operator's sense and experience.

Next, an explanation will be given on the operation of the conveying motor 25 in normal operation mode, not immediately after assembling the apparatus or after maintenance/replacement of the conveying belt.

The sensor 28 detects an ambient operating temperature at startup of the conveying motor 25. When the detected temperature is lower than a specification range as shown in FIG. 9A, operate the conveying motor 30 at a low temperature for a certain time as a trial run as shown in FIG. 10A.

When the temperature in the machine is increased to higher than the lower limit of a specified ambient temperature range as shown in FIG. 9B, gradually increase the speed of the conveying motor 25 as shown in FIG. 10B. When the ambient operating temperature is increased to within a specified range by this operation, increase the speed of the conveying motor 25 up to a normal operation speed as shown in FIG. 10C.

In the low temperature state, as described above, a trial run is performed at a low speed, and the speed is gradually increased, and the startup motor speed for starting the conveying belt is controlled to optimum. This prevents displacement or coming off of the conveying belt, and prevents a paper jam.

FIG. 11 is a block diagram showing a drive control system of a conveying belt according to a second embodiment of the invention.

The same components as those of the first embodiment are given the same reference numerals, and detailed explanation of the components will be omitted.

In the second embodiment, there are provided a first measuring device 31 to measure the time passed after installation of a conveying belt, a second measuring device 33 to measure a cumulative operating time of the conveying motor 25, and a third notify device 35 as a third notify device to notify a replacement period of the conveying belt 21.

In the second embodiment, a replacement period of the conveying belt 21 is notified before the life of the belt is expired, based on the cumulative operating time of the conveying motor 25, the time passed after installation of the conveying belt, and the results of detection of the amount of displacement of the conveying belt, a paper jam caused by the end of the life of the belt.

For example, as shown in FIG. 2A, the cumulative operating time of the conveying motor 25 and time passed after installation of the conveying belt are measured, and if the conveying system is judged not to have been operated for a certain period based on the measurement data, automatically operate the conveying motor 25 at a low speed for a certain time, and gradually increase the motor speed, so that the amount of displacement of the conveying belt 21 falls within a specified range of UL-UL as shown in FIG. 13A.

When the conveying system has been continuously operated and the conveying belt does not reach the end of its life as shown in FIG. 12B, the amount of displacement of the belt is within the specified range (UL-UL).

However, when the cumulative operating time of the conveying motor 25 is long and the conveying belt 21 is going to reach the end of life as shown in FIG. 12C, the conveying belt 21 expands and largely zigzags as shown in FIG. 13C.

When the life of the conveying belt 21 comes close to the end and the conveying belt 21 largely zigzags, the control device 29 judges it timing of replacing the belt, and the third notify device 25 notifies to replace the conveying belt.

According to the second embodiment, when the conveying system has not been operated for a certain period, the system is automatically operated at a low speed as a trial run and the motor speed is gradually increased, and the conveying belt is prevented from displacing or coming off, and a paper jam is prevented.

When the life of the conveying belt comes close to the end, it is notified to the third notify device 35, and the conveying belt can be replaced before the life is expired, and a paper jam is prevented.

FIG. 14 is a block diagram showing the drive control system of a conveying belt according to a third embodiment of the invention.

The same components as those of the first embodiment are given the same reference numerals, and detailed explanation of the components will be omitted.

In the third embodiment, there are provided a jam detection sensor 37 as a jam detection device to detect a paper jam, and a display unit 39 to display a first paper sheet causing a paper jam.

When a paper jam is detected by the jam detection sensor 37, the control device 29 displays a first paper sheet causing a paper jam, in the display unit 39.

The operator watches the display 39, opens the door 100a of the main body, and eliminates the jammed paper sheet. When the door 100a is opened, the safety switch 41 is turned on, and the power of the conveying roller system is turned off, thereby ensuring the safety. Leave the paper sheets other than the one causing the paper jam stayed on the conveying path as they are, and close the door 100a. The reset switch 43 is depressed, and the detection sensor 27 detects the position of the conveying belt after the paper jam, displacing or coming off, if any, and issues a corrective instruction, if there is any problem.

When the position of the belt, displacing or coming off is not detected by the sensor 27, start the conveying belt 21 at a low speed, and convey the paper sheets stayed on the conveying path to the stacking box, while checking the belt for meandering.

When the detection sensor 27 detects that the conveying belt 21b comes off after a paper jam, as shown in FIG. 15, the control device 29 does not operate the conveying motor 25 as shown in FIG. 16A. If the conveying motor 25 is operated while the conveying belt 21 is coming off or being largely displaced, a serious secondary paper jam may occur, and the conveying belt 21 may be broken. The conveying motor 25 is not operated to prevent such a serious trouble.

When the detection sensor 27 detects that the conveying belt 21 does not come off the roller 22, start the conveying motor 25 at a low speed as shown in FIG. 16B, and gradually increase the speed of the conveying motor 25 after the displacement of the conveying belt is improved as shown in FIG. 17B.

When the amount of displacement of the conveying belt 21 falls with given limits as shown in FIG. 17C, increase the speed of the conveying motor 30 to a normal operation speed as shown in FIG. 16C.

As described hereinbefore, according to the embodiment of the invention, assembling and maintenance of the apparatus can be safely performed with the door 100a closed. Besides, the positions, displacement and zigzag movement of the conveying belts 21a and 21b are monitored by the detection sensor 27. Therefore, the low-speed trial run time and the rising curve when increasing the speed can be optimally controlled.

Further, when the apparatus is operated at a low temperature or not operated for a long time, start of the conveying motor 25 is automatically controlled to a low speed, and the conveying belts 21a and 21b are familiarized to the conveying system. This stabilizes the conveying performance.

Moreover, displacing and meandering of the conveying belts 21a and 21b are self-diagnosed, and the maintenance/replacement period is notified. Therefore, the symptoms of coming off of the belt can be previously collected, a replacement notice can be issued before the life of the belt is expired, and a paper jam can be prevented.

If a paper jam should occur, the operator can clear the paper jam simply by opening the door 100a, removing a first paper sheet causing the jam, and closing the door 100a. The operator can automatically startup the apparatus while self-diagnosing the displacement and zigzag movement of the belt. This improves the operability.

Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

Claims

1. A paper sheet conveying apparatus comprising:

a conveying belt which moves and conveys a paper sheet;

a detection device which detects the amount of displacement of the conveying belt from a reference position while moving; and

a control device which drives the conveying belt at a low speed when a new device is installed as a conveying belt and initially started up, and after the low-speed driving, variably controls the speed of the conveying belt based on the amount of displacement of the conveying belt detected by the detection device.

2. The paper sheet conveying apparatus according to claim 1, wherein the control device leaves the conveying belt driven at a low speed when the amount of displacement of the conveying belt is over a predetermined value, gradually increases the speed of the conveying belt as the amount of displacement of the conveying belt is decreased, and increases the speed of the conveying belt to a predetermined speed when the amount of displacement of the conveying belt falls within given limits.

3. The paper sheet conveying apparatus according to claim 2, further comprising a first notify device which notifies an estimated time that the amount of displacement of the conveying belt falls within given limits.

4. The paper sheet conveying apparatus according to claim 3, further comprising a second notify device which notifies states that the amount of displacement of the conveying belt is over a predetermined value, decreased, and falls within given limits, respectively.

5. A paper sheet conveying apparatus comprising:

a conveying belt which moves and conveys a paper sheet;

a detection device which detects the amount of displacement of the conveying belt from a reference position while moving;

a temperature detection device which detects an ambient operating temperature of the conveying belt; and

a control device which drives the conveying belt at a low speed when the temperature of the conveying belt at startup of driving detected by the temperature detection device is lower than a reference temperature, and after the low-speed driving, controls the speed of the conveying belt based on the amount of displacement of the conveying belt detected by the detection device.

6. The paper sheet conveying apparatus according to claim 5, wherein the control device controls to gradually increase the moving speed of the conveying belt as the temperature detected by the temperature detection device is increased, and to increase the moving speed of the conveying belt to a predetermined speed when the temperature detected by the temperature detection device becomes a predetermined value.

7. A paper sheet conveying apparatus comprising:

a conveying belt which moves and conveys a paper sheet;

a detection device which detects the amount of displacement of the conveying belt from a reference position while moving;

a judgment device which judges whether the conveying belt has been stopped for over a certain period, at startup of driving the conveying belt; and

a control device which drives the conveying belt at a low speed when the judgment device judges the conveying belt to have been stopped for over a certain period, and after the low-speed driving, controls the speed of the conveying belt based on the amount of displacement of the conveying belt detected by the detection device.

8. The paper sheet conveying apparatus according to claim 7, further comprising a measuring device which measures a cumulative driven time of the conveying belt, and time passed after the installation of the conveying belt,

wherein the judgment device judges whether the conveying belt has been stopped for over a certain time, based on the value measured by the measuring device.

9. The paper sheet conveying apparatus according to claim 8, further comprising a third notify device which notifies replacement of the conveying belt, based on the amount of displacement of the paper sheet detected by the detection device, the cumulative driven time of the conveying belt measured by the measuring device, and the time passed after the installation of the conveying belt.

10. A paper sheet conveying apparatus comprising:

a conveying belt which moves and conveys a paper sheet;

a jam detection device which detects a jam of a paper sheet conveyed by the conveying belt;

a detection device which detects the amount of displacement of the conveying belt from a reference position after the paper jam is cleared;

a judgment device which judges whether the conveying belt is to be driven, based on the amount of displacement of a paper sheet detected by the detection device; and

a control device which drives the conveying belt at a low speed, when the judgment device judges the conveying belt to be driven, and after the low-speed driving, variably controls the speed of the conveying belt based on the amount of displacement detected by the detection device.