JPH09236402A - Device for detecting thickness of paper sheets or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance detection accuracy of an abnormal thickness of paper sheets or the like, to prevent it from jamming or diagonally advancing and to achieve long life of a roller in connection with a detection mechanism of thickness of a the paper sheets capable of controlling a conveying speed of a movable roller when the thickness of the paper sheets is detected. SOLUTION: A detection mechanism comprises a conveying passage 4 in which paper sheets 1 or the like is conveyed, fixing roller 9 and movable roller 10 which are projected in the conveying passage 4 and are rotated to be contacted to the paper sheets 1 for passing the paper sheets 1 thorough the contacting position, a support member 11 that rotatably supports the movable roller 10 at the both ends by displacing it from the contacting position with the fixing roller 9 to the shunting position, an electromagnetic force generating means 18 that generates a suppressing force that suppresses speeds of the movable roller 10 which shunts from the fixing roller 9 and support member 11 and a detecting means 16 that detects whether or not displacement amount of the shunting of the movable roller 10 exceeds a predetermined value. When the detecting means detects the fact that the amount exceeds the predetermined value, it is judged that the thickness of the paper sheets 1 exceeds a predetermined value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper sheet thickness detecting mechanism used in a paper sheet handling apparatus for handling paper sheets, and more particularly, the paper sheets pass between a fixed roller and a movable roller. The present invention relates to a paper sheet thickness detection mechanism capable of suppressing the moving speed of a movable roller at the time.

Recently, automatic teller machines such as an automatic teller machine (ATM) and an automatic teller machine (Cash Dispenser: CD) are widely used in banks and the like. In these devices, a paper sheet handling device for feeding and processing paper sheets such as banknotes one by one is incorporated.

In the paper sheet handling apparatus, when a plurality of bills to be handled are fed out (double feed), or when the bills are broken and repaired with an adhesive tape or the like, a counting error or a jam occurs during transportation. There is an obstacle that occurs. It is also necessary to avoid using dirty or ugly adhesive tape repaired bills as dispensed bills.

Therefore, there is provided a detection mechanism for rejecting a banknote unsuitable for such dispensing at the time of depositing / dispensing, and the bill or the like passes between the fixed roller and the movable roller which are in pressure contact with each other, so that the movable roller is moved. The thickness is measured from the amount of displacement of the moving object, and rejected when it exceeds a predetermined value.

However, since the bill enters between the fixed roller and the movable roller at a high speed, it takes time until the movable roller bounces up and the displacement vibration converges, so that it is difficult to discriminate the thickness.

In order to reduce the convergence time, an attempt has been made to increase the inertia of the frame that moves together with the movable roller, but since the detection mechanism becomes large, it is possible to improve it from the conditions such as device size. Have difficulty. Therefore,
There is a need for a solution to this.

[0007]

2. Description of the Related Art An example of a bill handling apparatus incorporated in an automatic teller machine will be described with reference to FIG. Banknote as shown
1a is stored by denomination, and a storage box equipped with feeding mechanisms 3a and 3b
2a, 2b, a reject box 2c for rejecting, a feeding roller R and a gate G are arranged to convey a bill 1a fed out at a high speed, a conveying path 4a, a thickness abnormality of the bill 1a, a double feed, a denomination and the like are discriminated. It is composed of a discrimination counting unit 5 for counting the amount to be dispensed, a pool unit 6 for temporarily pooling the dispensing banknote 1a, and a dispensing port 7.

Therefore, when the bills 1a of the amount requested by the customer are fed out from the storage boxes 2a, 2b by the feeding mechanisms 3a, 3b,
The banknote 1a is conveyed through the conveying path 4a, discriminated by the discrimination counting unit 5, and sent to the pool unit 6.

The counted amount is displayed on a display (not shown), and the banknote 1a of the pool section 6 is sent to the dispensing port 7 and dispensed by the customer's confirmation button input. During this time, if there is an abnormality in the thickness of the banknote 1a, double feed, inability to distinguish, etc.
The gate G at the branch point of the transport path 4a operates and is rejected by the reject box 2c.

The discrimination / counting unit 5 has an abnormality in the bill 1a.
(There are bills and the like that are broken or broken, or repaired with adhesive tape or the like.), And a thickness detection mechanism 8 for determining double feed or the like is provided.

In the thickness detection mechanism 8, the bill 1a is stored in the storage boxes 2a and 2b.
When the paper is double-fed from the machine, or when the mixed abnormal bills are fed out and conveyed as it is, it causes counting errors and jams, and this is prevented, and abnormal bills are not suitable for withdrawal. Therefore, it is provided for removal.
This will be described in detail below.

As shown in the partial sectional front view of FIG. 10 and the partial sectional side view of FIG. 11, a fixed roller is provided below the conveying path 4a.
A movable roller 10a is arranged on the upper side of 9a. Both ends of the movable roller 10a are supported, and springs are respectively attached to both ends of the upper surface.
A roller frame 11a is attached to the apparatus frame 14 via 12a and 12b and ring-shaped rubber dampers 13a and 13b.

Therefore, the movable roller 10a includes the spring 12
a, 12b and rubber dampers 13a, 13b are biased to the fixed roller.
Pressed against 9a. The fixed roller 9a is driven in the direction in which the banknote 1a is conveyed, and also has the same function as the feed roller R.

Displacement plates 15a, 15b made of a conductive material are formed on the side surfaces of the roller frame 11a at both ends in the longitudinal direction.
And magnetic sensors 16a and 16b constituted by eddy current gap measuring devices are provided facing the displacement plates 15a and 15b.
The magnetic sensors 16a and 16b are connected to the control unit 17, respectively, and detect the displacements of the displacement plates 15a and 15b, which are raised by the movement of the movable roller 10a, and convert them into electric signals.

The control unit 17 measures the voltage of the electric signal output from the magnetic sensors 16a, 16b and compares it with the judgment reference voltage set corresponding to the thickness of each banknote 1a to make a judgment. Whether or not at least one has an abnormal thickness (abnormal bill or double feed) is determined depending on whether or not the reference voltage is exceeded.

With this structure, the bill 1a is conveyed through the conveying path 4a, and as shown in FIG.
9a and the movable roller 10a, the spring 12a,
The movable roller 10a moves away from the fixed roller 9a by the thickness of the bill 1a against the elasticity of the rubber dampers 12a and 13b, and the roller frame 11a moves upward and the displacement plates 15a, 15b rise.

The magnetic sensors 16a, 16b are responsive to the ascending displacement.
The output voltage from changes, the change in voltage is measured by the control unit 17, and it is determined whether or not there is an abnormality by comparing each with a determination reference voltage,
If at least one is abnormal, the banknote 1a is rejected.

[0018]

According to the above-mentioned conventional method, when a bill enters between a fixed roller and a movable roller at a high speed, the movable roller often jumps upward to cause a displacement vibration having a large amplitude. Becomes The displacement vibration is converged by the elasticity of the spring and the damper, but it takes time to converge.

That is, as shown in FIG. 13 which shows the relationship between the passage of time and the displacement vibration, the time T ₀ until the vibration of the displacement output of the magnetic sensor converges to the amplitude a capable of determining the thickness L of the bill cannot be determined. Becomes Further, during this time T _0, the banknotes are separated from the fixed roller and the movable roller and the carrying force becomes 0, so that the steady carrying force is not transmitted to the banknotes, and a jam or skew may occur.

Therefore, a measure is taken to increase the inertia of the roller frame so that the time T ₀ can be shortened so that the thickness can be discriminated and that jamming and skewing can be prevented. However, since the detection mechanism becomes heavy and large, and the pressure contact force between the fixed roller and the movable roller becomes large, the bills passing through are easily damaged (further damaged if there is a tear), and the life of the roller is shortened. There is an adverse effect. Moreover, it is difficult to realize the device even under the condition that the device size is required to be downsized, and it is difficult to shorten the unidentifiable time T ₀ . There is a problem.

According to the present invention, it is possible to improve the accuracy of detecting an abnormality in the thickness of a conveyed sheet, prevent jams and skews, and extend the life of the roller. It is intended to provide a mechanism.

[0022]

FIG. 1 is a diagram illustrating the principle of the present invention. In the figure, 1 is a paper sheet, 4 is a transport path through which the paper sheet 1 is transported, 9 and 10 project into the transport path 4 and roll contact, and the transported paper sheet 1 passes through the rolling contact position. A fixed roller and a movable roller, 11 is a support member that rotatably supports the movable roller 10 at both ends, and supports so as to be retractable from rolling contact with the fixed roller 9, and 18 is a movable roller 10 and a support that retracts from the fixed roller 9. A magnetic force generating means for generating a magnetic force for suppressing the speed of the member 11 and a detecting means 16 for detecting whether or not the retracting displacement of the movable roller 10 exceeds a predetermined value when the paper sheet 1 passes.

When the detecting means 16 detects that the thickness exceeds the predetermined value, it is determined that the paper sheet 1 has exceeded the predetermined thickness. Therefore, the speed at which the movable roller 10 retracts from the fixed roller 9 due to the passage of the paper sheet 1 is suppressed by the magnetic force of the magnetic force generating means 18, the retracting speed of the movable roller 10 decreases, and the movable roller 10 retracts at a low speed. The amplitude of the output vibration of the means is reduced, the time for converging to a level at which the thickness can be detected is shortened, and the thickness detection accuracy of the paper sheet 1 is improved.

Further, the jumping of the movable roller 10 at the time of passing the paper sheet 1 can be suppressed, and the occurrence of jam and skew can be prevented. Further, since the movable roller 10 is not pressed against the fixed roller 9 more than necessary so that the inertia of the supporting member in the conventional method is increased and the pressed contact is made, the life of the fixed roller 9 and the movable roller 10 is not affected.

Claim 2: The detecting means 16 is provided at positions corresponding to both ends of the movable roller 10, respectively. Therefore, it is possible to easily detect which position on the paper sheet 1 has the thickness abnormality.

Claim 3: The magnetic force generating means 18 comprises a supporting member 11
The movable roller 10 is provided at a position corresponding to at least both ends thereof. Therefore, the force of suppressing the displacement speed of the movable roller 10 by the magnetic force generation means 18 can be applied according to the position where the movable roller 10 is displaced.

Claim 4: The magnetic force generating means 18 comprises a support member 11
Of the movable roller 10 and a columnar member formed on a surface opposite to the movable roller 10 and formed of a material having a non-magnetic property and an electrical conductivity, and the columnar member having an inner diameter capable of being fitted through a gap.
A coil 10 is fixedly provided at a position where at least a part of the columnar member is fitted into the fixed roller 9 when it is rollingly contacted with the fixed roller 9, and a direct current is applied to the coil.

Therefore, when a direct current is applied to the coil, a magnetic field is generated in the coil, and when the paper sheet 1 passes,
The movable roller 10 retreats from the fixed roller 9, and the magnetic force that suppresses the speed of the columnar member moving in the coil acts to suppress the retracting speed of the movable roller 10.

Claim 5: The magnetic force generating means 18 comprises a supporting member 11
Of the columnar magnet provided on the surface opposite to the movable roller 10 and the magnet when the movable roller 10 is in rolling contact with the fixed roller 9 and has an inner diameter that allows the magnet to be inserted through a gap. The tip is composed of a coil fixedly provided at a position near the one end, and a direct current is applied to the coil in a direction in which the same polarity as that of the tip of the magnet opposes the coil.

Therefore, by applying a direct current in the direction in which the same polarity as the polarity of the tip of the magnet opposes the coil,
The movement of the magnet is suppressed by the magnetic pole generated in the coil and the repulsive force of the homopolar magnetic force of the magnetic pole of the magnet retracted from the fixed roller 9 and fitted into the coil when the paper sheet 1 passes. The retracting speed of the movable roller 10 can be suppressed.

Claim 6: The magnetic force generating means 18 is constructed so that a direct current is applied to the coil for a time period during which the paper sheet 1 being conveyed passes between at least the fixed roller 9 and the movable roller 10. There is.

Therefore, energy can be saved by energizing the coil only while the paper sheet 1 passes at least between the fixed roller 9 and the movable roller 10. Moreover, in the case of claim 5, when the paper sheet 1 is not passed, the movable roller 10 by the magnetic force generating means 18 is fixed to the fixed roller 9.
Since no pressing force is applied to, the pressing force can be prevented from becoming excessive and the movable rollers 10 and the fixed rollers 9 can have a long life.

Claim 7: An elastic member is provided between the surface of the supporting member 11 on which the columnar member or the magnet is provided and the coil. Therefore, a desired pressure contact force can be applied to the rolling contact between the fixed roller 9 and the movable roller 10.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 to 4 in which the present invention is applied to the thickness detecting mechanism described in the conventional example will be described with reference to FIGS. The same reference numerals indicate the same objects throughout the drawings.

1) Example 1 Example 1 will be described with reference to FIGS. FIG. 2 shows the first embodiment.
Is a front sectional view showing the configuration of FIG. 3, FIG. 3 is a side sectional view of the first embodiment,
FIG. 4 is an explanatory diagram of the first embodiment, and FIG. 5 is a displacement vibration diagram showing the effect of the first embodiment.

As shown in FIGS. 2 and 3, the thickness detecting mechanism
In 8a, magnetic force generation mechanisms (magnetic force generation means) 18a and 18b are provided on both ends of the roller frame (support member) 11a in the longitudinal direction.

The magnetic force generating mechanisms 18a and 18b are roller frames.
The studs 19a and 19b made of a non-magnetic and electrically conductive material such as aluminum, which are set up at the center position of the width direction of 11a, and the rubber dampers 13a and 13b arranged on the upper surface of the roller frame 11a. The bobbins 21a and 21b are formed by winding the wound coils 20a and 20b, and the upper surfaces of the bobbins 21a and 21b are fixed to the apparatus frame 14, respectively. Bobbin 21a,
The hole diameter of 21b is formed so that the studs 19a, 19b can be fitted through the gap, and in the normal state, the tips of the studs 19a, 19b are fitted to almost the center position in the holes of the bobbins 21a, 21b.

The magnetic sensor 16a (16b) and the coils 20a, 20b are connected to the control unit 17a, and the control unit 17a has the functions of the control unit 17 described in the conventional example, and the coil 20a, 20a,
Apply DC current to 20b. Here, the energization direction may be either direction. Therefore, a DC brake is constituted by the studs 19a, 19b and the coils 20a, 20b to which a DC current is applied.

Due to such a constitution, as shown in FIG. 4, the bill 1a conveyed through the conveying path 4a is fixed to the fixed roller.
When the movable roller 10a is pushed up and starts to be displaced when it enters the rolling contact position of the movable roller 10a and the movable roller 10a, the studs 19a, 20b are generated in the magnetic field generated in the coils 20a, 20b to which the direct current is applied. A magnetic force acts in a direction that prevents the movement of 19b and acts as a brake to suppress the displacement speed of the movable roller 10a that moves together with the studs 19a and 19b.

Therefore, the bill 1a is moved to the fixed roller 9a and the movable low.
Displacement of the movable roller 10a when entering the rolling contact position of the roller 10a
As the speed decreases, jumping up is prevented, as shown in Fig. 5.
The vibration of the detection output of the magnetic sensors 16a, 16b is reduced,
The time to converge to the amplitude a that can judge the thickness L of the coin 1a is faster
Therefore, the thickness undetectable time described in FIG.
₀To T₁Can be shortened to

Further, the bill 1a is never separated from the fixed roller 9a and the movable roller 10a, the carrying force does not become zero, and jamming and skewing are prevented. In this way,
Simple mechanism, small size, light weight, high detection accuracy, and bill 1a
It is possible to obtain a thickness detection mechanism in which the conveyance of is stable.

2) Embodiments 2 and 3 Embodiments 2 and 3 will be described with reference to FIGS. 6 and 7.
6 is a partial cross-sectional side view showing a second embodiment, and FIG. 7 is a third embodiment.
FIG. In both cases, the thickness detection mechanism is provided at the positions corresponding to both ends of the movable roller 10a as in the first embodiment, but since it is the same mechanism, only one side is shown.

The second embodiment differs from the first embodiment in that a spring is used instead of the rubber damper. The third embodiment differs from the first embodiment in that both the rubber damper and the spring are used.

That is, as shown in FIG. 6, the thickness detecting mechanism 8b
The magnetism generating mechanism 18c of the roller frame 11a and the bobbin 21
A spring 12c is provided around the stud 19a between a and a.

Further, as shown in FIG. 7, the thickness detecting mechanism 8c
The magnetism generating mechanism 18d of FIG. 1 mounts the spring 12c on the roller frame 11b, and the stud 19
a and the frame 11c on which the rubber damper 13a is placed are fixed,
The upper end of the rubber damper 13a is fixed to the bobbin 21a.

With the above-mentioned structure and the same operation as in the first embodiment, the same effect can be obtained. Therefore, selection and combination can be performed depending on the pressing force of the fixed roller 9a and the movable roller 10a, the conveyance speed, the thickness of the paper sheet to be detected, and the like.

3) Fourth Embodiment A fourth embodiment will be described with reference to a partial sectional side view of FIG. The fourth embodiment differs from the first to third embodiments in that the stud and the coil are replaced with direct current (direct current brake), and direct current is supplied so that the magnet and the coil have the same polarity.

That is, as shown in FIG. 8, the thickness detecting mechanism 8d
In the magnetism generating mechanism 18e, a columnar magnet 22a is fixed to the center position of the frame 11c with the N pole (or S pole) facing upward. The coil 20a has a lower N pole (or S
The magnet 22a and the coil 20a are set so as to pass a direct current in the direction in which they become the same pole. Roller frame 11b and frame 11
A rubber damper 13a is provided between c.

Further, light transmission type sensors S1 and S2 are provided on the conveying path 4a before and after the rolling contact position of the fixed roller 9a and the movable roller 10a. The coil 20a and the sensors S1 and S2 are control units.
It is connected to 17b.

The control unit 17b is the control unit described in the first embodiment.
In addition to having the function of 17a, a direct current is applied to the coil 20a by a detection signal detected by the sensor S1 at the leading edge of the bill 1a conveyed through the conveying path 4a, and the rear end of the bill 1a is detected by the sensor S2 (actually, it is detected. Coil 20a according to the released detection signal
Stop the energization.

With this configuration, as shown in the figure, the leading edge of the bill 1a conveyed through the conveyance path 4a is detected by the sensor.
When S1 detects, a direct current is passed through the coil 20a and an NS magnetic field is generated in the coil 20a. In this case, the repulsive force due to the magnetic field of the coil 20a acts on the magnet 22a, and the force for pressing the movable roller 10a against the fixed roller 9a increases.

The bill 1a is a fixed roller 9a and a movable roller 10a.
When the movable roller 10a is pushed up and starts to be displaced, the N pole (or S pole) of the magnet 22a is entered.
Magnetic repulsive force between the pole) and the N pole (or S pole) of the coil 20a prevents the magnet 22a from moving in the magnetic field.
The displacement speed of the movable roller 10a that moves together with the magnet 22a is suppressed.

The thickness of the banknote 1a is detected, and the rear end is the sensor S2.
When it is detected, the power supply to the coil 20a is stopped.
Therefore, as the displacement speed of the movable roller 10a decreases, the jumping up is prevented, the vibration of the detection output of the magnetic sensor 16a is reduced, and the thickness L of the banknote 1a is reduced as described with reference to FIG.
The time to converge to the amplitude a that can be determined is shortened, the detection accuracy is improved, and the same effect as that of the first to third embodiments can be obtained.

Further, the sensors S1 and S2 are provided before and after the rolling contact position between the fixed roller 9a and the movable roller 10a so that the bill 1a can be detected by the sensor.
Since the coil 20a is energized for the time of passing between S1 and S2, that is, the time for detecting the thickness, the time when the movable roller 10a is pressed against the fixed roller 9a by the magnetic force generated in the coil 20a is limited. , Fixed roller 9a and movable roller
The life of 10a can be extended. Moreover, it is possible to save power consumption, which is an energy saving effect.

As an application example of the present invention, although not shown, not only in the thickness detecting mechanism, but also in the conveyance of paper sheets such as banknotes by the feed roller and the pressing roller in the conveyance path, when the paper sheets pass, This method can be applied as a method of eliminating unstable conveyance due to the bounce of the pressing roller and preventing jamming and skewing.

The method of providing the sensors S1 and S2 of the fourth embodiment may be applied to the first to third embodiments, and the same effect can be obtained. In the above example, the case where the magnetic sensor is used as the means for detecting the displacement of the displacement plate has been described, but other members may be used as long as they detect the displacement and convert it into an electric signal, for example, a potentiometer or an optical sensor. Also good.

Further, in the above example, the case of the thickness detecting mechanism in the bill handling device of the CD is explained, but not only the bill handling device of another automatic transaction device, but also another device handling paper sheets, for example, a slip. The present invention can be similarly applied to a medium handling device such as a card.

[0058]

As described above, according to the present invention, the retracting speed of the movable roller is suppressed and becomes low, the amplitude of the detection output of the detecting means becomes small, and the thickness converges to a level at which the thickness can be detected. The time is shortened, and the detection accuracy of the thickness of the paper sheet by the detection means is improved.

It is possible to prevent the movable roller from jumping up when a paper sheet passes, and prevent jamming and skewing. Energy can be saved by energizing the coil only while the paper sheet passes at least between the fixed roller and the movable roller.

When a magnet and a coil are used for the magnetic force generating means (Claim 5), when there is no paper sheet passing,
Since the force for pressing the movable roller against the fixed roller by the magnetic force generating means is not applied, it is possible to prevent the pressing force from becoming excessive, and it is possible to extend the life of the movable roller and the fixed roller. This has the effect.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

FIG. 2 is a partial sectional front view showing the configuration of the first embodiment of the present invention.

FIG. 3 is a partial cross-sectional side view of the first embodiment.

FIG. 4 is an explanatory diagram of the first embodiment.

FIG. 5 is a diagram showing the effect of the first embodiment.

FIG. 6 is a partial sectional side view showing a second embodiment.

FIG. 7 is a partial cross-sectional side view showing a third embodiment.

FIG. 8 is a partial cross-sectional side view showing the fourth embodiment.

FIG. 9 is an internal side view of a bill handling device to which the present invention is applied.

FIG. 10 is a partial cross-sectional front view showing a conventional thickness detection mechanism.

11 is a partial cross-sectional side view of FIG.

FIG. 12 is an explanatory diagram of a conventional example.

FIG. 13 is an explanatory diagram showing the problems of the conventional example.

[Explanation of symbols]

1 is a paper sheet, 1a is a banknote, 4,4a
Is a transport path, 8,8a to 8d are thickness detection mechanisms,
9 and 9a are fixed rollers, 10 and 10a are movable rollers, 11 is a supporting member, 11a and 11b are roller frames,
11c is a frame, 12a to 12c are springs,
13a and 13b are rubber dampers, 15a and 15b are displacement plates, 16a and 16b are magnetic sensors, 17, 17a and 17b are control units,
18 is a magnetic force generating means, 18a to 18e are magnetic force generating mechanisms, 19
a, 19b are studs, 20a, 20b are coils, 21a, 21b
Is a bobbin, 22a is a magnet, S1 and S2 are sensors

Claims (7)

[Claims] 1. A transport path along which paper sheets are transported, a fixed roller and a movable roller that project into the transport path and roll-contact, and the transported paper sheets pass through the rolling contact position. A support member that rotatably supports and that can retract from rolling contact with a fixed roller, a magnetic roller that retracts from the fixed roller, and a magnetic force generation unit that generates a magnetic force that suppresses the speed of the support member; When the retracting displacement of the movable roller exceeds a predetermined value when the sheet passes, the paper sheet exceeds the predetermined thickness when the detecting means detects that the retracting displacement exceeds the predetermined value. A paper sheet thickness detection mechanism characterized by making a determination. 2. The paper sheet thickness detection mechanism according to claim 1, wherein the detection means are provided at positions corresponding to both ends of the movable roller, respectively. 3. The paper sheet thickness detecting mechanism according to claim 1, wherein the magnetic force generating means is provided at a position corresponding to at least both ends of the movable roller of the supporting member. 4. The magnetic force generating means includes a columnar member formed on a surface of the support member opposite to the movable roller, the columnar member being made of a non-magnetic and electrically conductive material, and the columnar member having a gap. It has an inner diameter that can be inserted through and has a coil fixedly provided at a position where at least a part of the columnar member is inserted when the movable roller is in rolling contact with the fixed roller. Electricity is supplied.
Alternatively, the paper sheet thickness detection mechanism according to claim 3. 5. The magnetic force generating means has a columnar magnet provided on a surface of the supporting member opposite to the movable roller, and an inner diameter into which the magnet can be fitted with a gap, The tip of the magnet when it is in rolling contact with the fixed roller is composed of a coil fixedly provided at a position near one end, and the same polarity as that of the tip of the magnet faces the coil. The sheet thickness detecting mechanism according to claim 1 or 3, wherein a direct current is applied. 6. The magnetism generating means is characterized in that the direct current is applied to the coil for a time period during which the conveyed sheet passes at least between the fixed roller and the movable roller. The paper sheet thickness detection mechanism according to claim 4 or claim 5. 7. The paper sheet thickness detection according to claim 4, wherein an elastic member is provided between the coil and the surface of the supporting member on which the columnar member or the magnet is provided. mechanism.