JP2013001530A - Paper thickness detecting device and paper thickness detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper thickness detecting device for quickly and accurately detecting a situation that paper sheets are stuck in a carrying path and cannot be carried by effectively utilizing data immediately before, and to provide its detecting method.SOLUTION: The paper thickness detecting device includes: a paper thickness detecting part 8 disposed in a carrying path 7 of paper sheets 6 for detecting and outputting a paper thickness; a threshold computing part 12 for computing a threshold on the basis of the detection output of the paper thickness detection part 8; a paper thickness comparison part 13 for comparing the detection output with the threshold; and a paper sheet carriage control part 14 for executing the control of continuing or stopping the carriage of the paper sheet 6 on the basis of a comparison result in the paper thickness comparison part 13. The detection output of the paper sheet 6 of the paper thickness detecting part 8 is compared with the threshold of the paper sheet 6 that has passed through the paper thickness detecting part 8 immediately before.

Description

The present invention relates to a paper thickness detection apparatus and a paper thickness detection method for early detection of a situation in which a paper sheet is not conveyed due to a conveyance path in a paper sheet conveyance system for conveying paper sheets.

In the paper thickness detection method for paper sheets such as scanners, printers, and copiers, there are cases where paper sheets that are recording media may be caught in the transport path due to the paper thickness or double feed. For example, when printing using paper of the same standard (A4, B4, etc.), since the paper thickness of the paper is usually constant, there is a problem that a trouble that can be caught in the conveyance path during the printing process does not occur. It is rare. However, when various paper sheets are conveyed and printed one after another, the paper thickness may inevitably vary regardless of the paper size.
Various techniques have been proposed for promptly detecting obstacles caused by such paper sheets having different paper thicknesses to the conveying device and ensuring smooth conveying means.

That is, for paper thickness detection, in recent years, there are transmitted light type and contact type methods,
Furthermore, paying attention to the fact that double feed has a close relationship with the paper thickness, an ultrasonic sensor is used for double feed detection, and a technology that can use double feed detection and paper thickness detection with an ultrasonic sensor has been developed. .

Specifically, for example, according to Japanese Patent Application Laid-Open No. H11-260707, a storage unit that can store a plurality of document sheets by an image reading device that uses a reception signal from an ultrasonic sensor common to paper thickness detection and double feed detection. Whether the original paper being conveyed from the original to the original reading unit is double-fed and the thickness of the original paper are to be detected at the same time. That is, attention is paid to the point that one ultrasonic sensor detects the double feed and the paper thickness of the original paper.
Further, according to Patent Document 2 below, emphasis is placed on detection of double feed of paper sheets, and an attempt is made to monitor double feed and paper thickness using the previous result.

In Patent Document 1 below, an abnormality in double feeding or paper thickness is detected with reference to a reception level curve of an ultrasonic sensor before the conveyance of a paper sheet. Such a standard is provided in consideration of the usage environment of the ultrasonic sensor.
Further, in Patent Document 2 below, a repeated conveyance unit of a plurality of paper sheets is referred to as one “job”, and the current job is compared with the previous job to detect double feeding of paper sheets. That is, a reference value is set based on “job”, and double feed detection is mainly performed.

However, such a technique has the following problems.
First, an error or a detection error is likely to occur in the detection result due to the type of paper sheet, the variation in the performance of the sensor itself, the usage environment of the sensor, and the like. Further, for example, since data on the relationship between the attenuation amount of the ultrasonic sensor and the paper thickness is indispensable, it is necessary to collect reliable information (data, etc.). Furthermore, in order to detect the presence or absence of double feed and an abnormality in the paper thickness, it is also necessary to set a fixed level that is set in advance, that is, an absolute reference, based on the collected data. For this reason, the reliability of data directly affects double feed detection and the like. As described above, in the paper thickness detection device and the paper thickness detection method in the prior art, a fixed reference such as an absolute value, a reference value, or a standard value is set, and the paper thickness is detected within the range to solve the problem. It was what controlled the occurrence.

JP 2009-161291 A JP 2002-36283 A

The present invention solves the problems inherent in the above-mentioned prior art without relying on such fixed criteria as absolute values, reference values, standard values, etc., and effectively utilizes data that fluctuates immediately before. In this way, a paper thickness detection device and a paper thickness detection method for quickly and accurately detecting a situation in which a paper sheet is not conveyed due to a conveyance path in a paper sheet conveyance method for conveying paper sheets are provided. There is to do.

That is, in order to achieve the above object, a paper thickness detection device according to the present invention includes a paper thickness detection unit that is disposed in a paper sheet conveyance path and detects and outputs a paper thickness, and the detection of the paper thickness detection unit. A threshold value calculation unit that calculates a threshold value based on the output; a paper thickness comparison unit that compares the detection output with the threshold value; and A paper sheet conveyance control unit for controlling the continuation or stop of conveyance, and the detection output of the paper sheet of the paper thickness detection unit is the threshold value of the paper sheet that has passed through the paper thickness detection unit immediately before Based on the comparison result, the paper sheet conveyance control unit performs the conveyance control of the paper sheet of the paper thickness detection unit.

  With this configuration, the paper sheet transported one after the other through the paper sheet transport path is an output signal level obtained by converting the detection output obtained by detecting the paper thickness of the immediately preceding paper sheet between successive paper sheets immediately before and immediately after. Since the transport of the immediately following paper sheet can be controlled by relative comparison with the threshold value set with reference to, a strict absolute reference or standard value is set to apply uniformly to all paper sheets transported in advance. There is no need. Further, there is no need to consider variations in performance of the sensor itself for detecting the output signal level, sensor usage environment, and the like.

Further, the paper thickness detection apparatus according to the present invention is configured such that the threshold value includes an upper limit threshold value and a lower limit threshold value, and the upper limit threshold value or the lower limit threshold value or both. The threshold value can be appropriately changed.

With this configuration, it is possible to more flexibly perform control of continuation or stop of the conveyance of the paper sheet whose output is being detected by the paper thickness detection unit.

In the paper thickness detection device according to the present invention, when the detection output is within the threshold value as a result of the comparison, the paper sheet transport control unit issues a control command to continue transporting the paper sheets. It is characterized by emanating.

The paper thickness detection device according to the present invention determines that the paper sheet is thin paper in the paper sheet transport control unit when the detection output exceeds the upper limit threshold value in the comparison result. And a control command is issued to stop the conveyance of the paper sheet.

In the paper thickness detection device according to the present invention, when the detection output does not reach the lower limit threshold value in the comparison result, the paper sheet conveyance control unit determines that the paper sheet is thick paper. And a control command is issued to stop the conveyance of the paper sheet.

The paper thickness detection unit includes a sensor including a sensor generation unit and a sensor reception unit.

In the paper thickness detection apparatus according to the present invention, the paper thickness detection unit is configured by an ultrasonic sensor including an ultrasonic wave generation unit and an ultrasonic wave reception unit.

The paper thickness detection device according to the present invention includes a paper thickness detection unit that is disposed in a paper sheet conveyance path and detects and outputs a paper thickness, and a threshold value based on the detection output of the paper thickness detection unit. Control of whether to continue or stop the conveyance of the paper sheet based on the comparison result of the threshold value calculation unit to calculate, the paper thickness comparison unit to compare the detection output and the threshold value, and the paper thickness comparison unit A sheet conveyance control unit for performing comparison between the sheet thickness detection output of the sheet thickness detection unit and a threshold value calculated by a combination of a plurality of sheets that have already passed through the sheet thickness detection unit. On the basis of the above, the paper sheet conveyance control unit performs the conveyance control of the paper sheet of the paper thickness detection unit.

With this configuration, it is possible to perform control with a higher degree of freedom in the conveyance control of the paper sheet whose output is being detected by the paper thickness detection unit.

The paper thickness detection method according to the present invention includes a paper thickness detection unit that is disposed in a paper sheet conveyance path and detects and outputs a paper thickness, and a threshold value based on the detection output of the paper thickness detection unit. Control of whether to continue or stop the conveyance of the paper sheet based on the comparison result of the threshold value calculation unit to calculate, the paper thickness comparison unit to compare the detection output and the threshold value, and the paper thickness comparison unit A paper sheet conveyance control unit for performing the paper sheet detection output of the paper thickness detection unit based on a result of comparison with a threshold value of a paper sheet that has passed through the paper thickness detection unit immediately before In the leaf conveyance control unit, the conveyance control of the sheet of the paper thickness detection unit is performed.

In the paper thickness detection method according to the present invention, the threshold value includes an upper limit threshold value and a lower limit threshold value, and the upper limit threshold value, the lower limit threshold value, or both The threshold value can be appropriately changed.

In the paper thickness detection method according to the present invention, when the detection output is within the threshold value as a comparison result, the paper sheet conveyance control unit issues a control command to continue the conveyance of the paper sheet. Features.

Further, in the paper thickness detection method according to the present invention, when the detection output exceeds the upper limit threshold value as a comparison result, the paper sheet conveyance control unit determines that the paper sheet is thin paper, A control command is issued to stop the conveyance of the paper sheet.

In the paper thickness detection method according to the present invention, when the detection output does not reach the lower limit threshold value as a comparison result, the paper sheet conveyance control unit determines that the paper sheet is a thick paper, A control command is issued to stop the conveyance of the paper sheet.

The paper thickness detection method according to the present invention is characterized in that the paper thickness detection unit includes a sensor including a sensor generation unit and a sensor reception unit.

The paper thickness detection method according to the present invention is characterized in that the paper thickness detection unit includes an ultrasonic sensor including an ultrasonic wave generation unit and an ultrasonic detection unit.

The paper thickness detection method according to the present invention includes a paper thickness detection unit that is disposed in a paper sheet conveyance path and detects and outputs a paper thickness, and a threshold value based on the detection output of the paper thickness detection unit. Control of whether to continue or stop the conveyance of the paper sheet based on the comparison result of the threshold value calculation unit to calculate, the paper thickness comparison unit to compare the detection output and the threshold value, and the paper thickness comparison unit A sheet conveyance control unit for performing comparison between the sheet thickness detection output of the sheet thickness detection unit and a threshold value calculated by a combination of a plurality of sheets that have already passed through the sheet thickness detection unit. On the basis of the above, the paper sheet conveyance control unit performs the conveyance control of the paper sheet of the paper thickness detection unit.

As described above, according to the present invention, it is possible to quickly and accurately detect a mixture of forms having different thicknesses. In addition, the influence of variations in the performance of the sensor itself as in the prior art and the environment in which the sensor is used can be eliminated as much as possible. Further, it is not necessary to determine a numerical value for strict paper thickness detection in advance. Furthermore, the present invention itself can be used to detect double feeding of paper sheets immediately after. Therefore, paper thickness detection, double feed detection, and paper thickness and double feed detection can be performed simultaneously.
In addition, the sensor used in the present invention can be used not only for an ultrasonic sensor but also for sensors of various detection methods such as a contact type and a transmission type. Furthermore, by providing a plurality of paper thickness detection units so as to be orthogonal to the paper sheet conveyance direction, for example, a sticker attached to a document can be easily detected.

It is the schematic of the paper thickness detection apparatus which concerns on embodiment of this invention. It is a conceptual diagram of a thin paper mixing detection pattern. It is a conceptual diagram of a thick paper mixing detection pattern. It is a wave form diagram of an ultrasonic reception signal when there is no paper sheet. It is a wave form diagram of an ultrasonic reception signal when thin paper is detected. It is a wave form diagram of an ultrasonic wave reception signal when detecting thick paper. It is a wave form diagram of an ultrasonic wave reception signal when double feed is detected. It is a figure which shows the relationship between paper thickness and a received signal level. It is a flowchart of the paper thickness detection in the conveyance process of paper sheets.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram of a paper thickness detection apparatus 1 according to an embodiment of the present invention. The paper thickness detection apparatus 1 according to the present invention includes a paper feed unit 2 that stacks paper sheets 6 and feeds them one by one, a pair of transport rollers 3 and 4, a discharge unit 5, a paper feed unit 2 and a discharge unit 5. Paper thickness detection which has the conveyance path 7 which conveys the paper sheet 6 which connects, and the ultrasonic generation part 9 and the ultrasonic reception part 10 which are arrange | positioned on both sides of the conveyance path 7 in the vicinity of a pair of conveyance rollers 3 and 4 A central processing unit (CPU) 11 that connects and controls the unit 8 and the paper thickness detection unit 8, a memory unit 15, and a drive system (not shown) for driving each unit of the paper thickness detection device 1. .

The paper thickness detection unit 8 is a paper thickness of the paper sheet 6 conveyed between the ultrasonic wave generation unit 9 and the ultrasonic wave reception unit 10 that are arranged near the pair of conveyance rollers 3 and 4 with the conveyance path 7 interposed therebetween. And the detection output as a result is output to the CPU 11 as a signal.
The CPU 11 stores a threshold value calculation unit 12, a paper thickness comparison unit 13, and a paper sheet conveyance control unit 14. The threshold calculation unit 12 calculates a threshold based on the output detected by the paper thickness detection unit 8. The paper thickness comparison unit 13 compares the output detected by the paper thickness detection unit 8 with the threshold value calculated by the threshold value calculation unit 12.
Based on the comparison result compared by the paper thickness comparison unit 13, the paper sheet conveyance control unit 14 controls the continuation or stop of conveyance of the paper sheet whose output is being detected by the paper thickness detection unit.
The memory unit 15 stores and stores a program for driving the entire system of the paper thickness detection apparatus 1 and data processed by the program.
Further, the calculation result processed by the CPU 11 is also stored.
Further, a necessary memory is output according to a command from the CPU 11.

Paper thickness detection in the paper thickness detection apparatus 1 according to the embodiment of the present invention having such a configuration will be described below with reference to FIGS.

As shown in FIG. 1, a large number of paper sheets 6 (6 a, 6 b...) Are stacked in the paper feeding unit 2. The paper sheet 6 is guided between the pair of transport rollers 3 and 4 sequentially from the first paper sheet 6a placed on the top, while being guided in the direction of the arrows of the auxiliary rollers 3a, 4a, 3b, and 4b. It is conveyed on the conveyance path 7 in the direction of the discharge unit 5. The sheet 6a of the first sheet 6a is detected by a sheet thickness detection unit 8 including an ultrasonic generation unit 9 and an ultrasonic reception unit 10 which are disposed in the vicinity of the pair of conveyance rollers 3 and 4 with the conveyance path 7 interposed therebetween. Thickness is detected. The paper thickness detection signal at this time is stored in the memory unit 15.

FIG. 2 is a conceptual diagram of a pattern in which mixing of thin paper is detected as a result of analysis by the CPU 11 to which the paper thickness detection signal is input. In this pattern, the received signal of the first paper sheet 6 a output from the paper thickness detection unit 8 is level-converted and stored in the memory unit 15. That is, the numerical value of the reception signal subjected to level conversion is the actual measurement value Y6a of the first sheet 6a.
However, the actually measured value Y6a is greatly affected by various external factors (for example, a detection error that is difficult to control that the surrounding environment gives to the ultrasonic wave generation unit 9 and the ultrasonic wave detection unit 10). Therefore, a range is set in consideration of the measurement error of the actual measurement value Y6a.

The paper thickness detection device 1 and the paper thickness detection method according to the present invention are the most effective use method of the allowable error by applying a threshold to the allowable error that inevitably occurs among such measurement errors. It is what.
As a specific example, the upper and lower threshold values set for the first sheet in FIG. 2 are set up and down based on the measurement error from the measured value Y6a. It is given by

Basic formula: upper threshold (upper threshold) = (N−1) th ultrasonic level + α

Here, N is an integer value of 2 or more, and the unit of the threshold value is V (volt).
Further, α is a% value with respect to a measurement result (in the present invention, the output signal level detected by the paper thickness detection unit 8) corresponding to a standard deviation (for example, + 3σ with respect to the median).

Therefore, according to this basic formula, the upper limit threshold (upper limit threshold) set for the first sheet = actual measurement value Y6a + α.

Basic formula: lower threshold (lower threshold) = (N−1) th ultrasonic level−β

Here, N is an integer value of 2 or more, and the unit of the threshold value is V (volt).
Β is a% value with respect to a measurement result (in the present invention, the output signal level detected by the paper thickness detection unit 8) corresponding to a standard deviation (for example, −3σ with respect to the median).

Therefore, according to this basic equation, the lower limit threshold (lower limit threshold) set for the first sheet = actual measurement value Y6a−β.

The range between the upper and lower threshold values Y6a + α and Y6a−β not only indicates the fact that the first sheet 6a in the paper thickness detection apparatus 1 has been normally conveyed, but also the received signal level. If it is within the actual measurement value Y6a ± error (threshold Y6a + α and Y6a−β range), it means that the second sheet 6b is allowed to be conveyed as the “normal range”. Therefore, the paper thickness detection device 1 can also be a relative determination unit for determining whether or not the conveyance of the paper sheet 6b can be permitted without any obstacle. That is, if the sheet thickness detection result of the second sheet 6b is within the range between the both threshold values Y6a + α and Y6a-β, it means that the sheet is conveyed with high probability without trouble.

In the present invention, the “normal range” is set by the addition (+ α) as the upper limit and the subtraction (−β) as the lower limit for the actually measured value, that is, the (N−1) th ultrasonic level. The meaning of this calculation is, for example, that the measured value Y6a is a raw measured value at the upper threshold value of the first sheet, and the added α value is obtained by adding the actual α value due to the detection error of the measured value Y6a. Is also within the error range. The same applies to the lower limit threshold value of the first sheet.
In the case of the paper thickness of the present invention in which a thickness that is susceptible to extremely delicate environmental conditions such as external temperature and humidity is measured, it is necessary to take into account measurement errors that occur inevitably. Therefore, this addition (+ α) and subtraction (−β) are also numerical values of measurement errors.

Even if a threshold is used for such a measurement error, the threshold range is not arbitrarily set. That is, the standard deviation (σ) as a rule of thumb works on the measured value. That is, the upper limit threshold and the lower limit threshold set by addition (+ α) or subtraction (−β) with respect to the actual measurement value Y6a are logically based on the statistical probability. Using this logic, the paper thickness range of the immediately preceding paper sheet that is constantly changing according to the upper threshold value and the lower threshold value (always changing fluctuation range) is the same as that of the immediately following paper. This is a criterion for determining whether or not the leaf can pass through the paper thickness detector 8.
For this reason, in the present invention, it is not necessary to set a so-called fixed numerical value or range such as an absolute value or a standard value of an allowable allowable paper thickness in advance, and to determine a conveyance condition using that value as an absolute reference.

Next, the relative relationship between the first sheet 6a and the second sheet 6b is applied as it is to the conveyance allowance after the second sheet 6b in FIG. For example, if the measured value Y6b ± error (range between threshold values Y6b + α and Y6b−β) of the received signal level of the second sheet 6b is within the normal range for the conveyance of the third sheet 6c. . That is, the conveyance permission condition for the third paper sheet 6c does not depend on the paper thickness detection result of the first paper sheet 6a, but the range based on the paper thickness detection result of the second paper sheet 6b ( It depends on the upper and lower thresholds).

However, in the same figure, as an example, the sheet thickness detection result (actual value Y6f) of the sixth sheet 6f is the actual value Y6e ± error (threshold values Y6e + α and 6Ye−β) of the fifth sheet 6e. The upper threshold value Y6e + α in the range (1) is exceeded. In this case, the paper thickness comparison unit 13 determines that the paper thickness detection result (actually measured value Y6f) of the paper sheet 6f is outside the allowable transport range and is a thin paper detection.
When such a determination is made, the determination signal is output to the paper sheet conveyance control unit 14, the drive system is shut off, and the drive of the conveyance path 7 and the like is stopped. The paper sheet 6f must be discharged.

FIG. 3 is a conceptual example of a pattern in which cardboard is detected. The concept itself is the same as the concept of the thin paper mixture detection pattern shown in FIG. Therefore, duplicate description is omitted.

In the example of the thick paper mixture detection pattern in FIG. 3, the paper thickness detection result (actual value Y6f) of the sixth paper sheet 6f is the actual value Y6e ± error (threshold values Y6e + α and Y6e−) of the fifth paper sheet 6e. The lower threshold value Y6e-β of (β range) is not reached.
In this case, the paper thickness comparison unit 13 determines that the paper thickness detection result (actually measured value Y6f) of the paper sheet 6f is out of the normal range and is thick paper detection. When such a determination is made, the drive system is shut off and driving of the transport path 7 and the like is stopped. The paper sheet 6f must be discharged.

Here, the actual measurement value and threshold value of each sheet in FIG. 3 have the same symbols as the actual measurement value and threshold value of each sheet in FIG. 2, but this is merely a display for convenience. Further, the relationship between the actually measured value and the upper or lower threshold value for the setting is not set to a uniform upper and lower limit value with respect to the actually measured value for each sheet. That is, the threshold value can be set arbitrarily. Therefore, for example, the range between the upper and lower limits may be different between the actual measurement value Y6a and the actual measurement value Y6b. Also, there is no necessity to make the absolute values of α and β the same. For this reason, one of the upper and lower thresholds may be larger than the actual measurement value. Also, there is no necessity to program α and β using the standard deviation (σ).

In the above description, based on the comparison result between the detection output of the paper sheet of the paper thickness detection unit and the threshold value of the paper sheet that has passed through the paper thickness detection unit immediately before, the conveyance of the paper sheet of the paper thickness detection unit In the present invention, the comparison target of the paper sheet detection output of the paper thickness detection unit is not limited to the “threshold value of the paper sheet that passed the paper thickness detection unit immediately before” in the present invention. It is. That is, the comparison target may be a “threshold value calculated by combining a plurality of paper sheets that have already passed through the paper thickness detection unit”. Therefore, for example, based on the detection output of two sheets of the paper sheet that has passed through the paper thickness detection unit immediately before (referred to as the front one paper sheet) and the paper sheet that has passed through the front paper thickness detection unit (two front paper sheets). Thus, the threshold value to be compared may be calculated. Further, a paper sheet that has already passed the paper thickness detection unit five sheets ago, such as the previous five paper sheets, can be set as a comparison target threshold value. That is, the use of the present invention is greatly expanded by appropriately using a combination of the previous N sheets or one of them.

4 to 7 show waveform diagrams of received signals. FIG. 4 is a diagram of the waveform W1 of the ultrasonic reception signal when there is no paper sheet. FIG. 5 is a diagram of a waveform W2 of the ultrasonic reception signal when thin paper is detected. FIG. 6 is a diagram of a waveform W3 of the ultrasonic reception signal when cardboard is detected. Further, FIG. 7 is a diagram of a waveform W4 of the ultrasonic reception signal when the double feed is detected. In all of these figures, the received signal voltage is taken in the vertical axis (Y-axis) direction, and the time is taken in the horizontal axis (X-axis) direction. The received signal voltage is in volts and the time is in seconds. When these waveforms are compared, the amplitude at the center of the waveform W1 of the ultrasonic wave reception signal when there is no paper sheet is the largest, and the central amplitude is in the order of the thin paper detection waveform W2, the thick paper detection waveform W3, and the double feed detection waveform W4. It gets smaller. This is because the received signal of the ultrasonic detection unit 9 is affected by the degree of failure of the ultrasonic wave from the ultrasonic wave generation unit 8 (characteristics such as the presence or absence of paper sheets and thickness). The reason why the double feed detection generally has the smallest amplitude is that, in addition to the overlap thickness of the paper sheets, an air layer is interposed between the overlaps at the time of double feed.

These waveform characteristics serve as reference data for determining the upper and lower thresholds.

FIG. 8 is a diagram showing the relationship between the paper thickness and the received signal level. From the curve P in this figure, it can be seen that the received signal level in FIGS. 4 to 7 has a close correlation with the paper thickness.

Next, the flow of paper thickness detection in the paper thickness detection apparatus 1 of this embodiment will be summarized with reference to the flowchart shown in FIG.

First, a predetermined start switch provided in the paper thickness detection device 1 is operated to turn on the drive unit and the like.
Paper sheets stacked on the paper supply unit 2 (hereinafter simply referred to as “paper sheets”) shift to the transport start mode (S101). When the conveyance start button is pressed, the first sheet 6a, which is the uppermost sheet 6 among the sheets 6, passes through the gap between the pair of conveyance rollers 3 and 4 and passes through the conveyance path 7. It is conveyed in the feed direction (the arrow direction in FIG. 1) (S102).

The ultrasonic signal level of the first paper sheet 6a is sampled by the transmission sensor 9 and the reception sensor 10 that are arranged near the pair of conveyance rollers 3 and 4 with the conveyance path 7 interposed therebetween (S103).
The collected ultrasonic level is output to the CPU 11 and processed by the threshold calculation unit 12 to set upper and lower threshold values. The upper and lower threshold values are stored in the memory unit 15 as the normal range R2.
The normal range R2 is a reference for controlling the conveyance of the second sheet 6b.

When the first sheet 6a reaches between the transmission sensor 9 and the reception sensor 10, the second sheet (corresponding to N = 2) is fed out from the sheet feeding unit 2 (S104). The first sheet 6a that has passed through the gap between the pair of conveying rollers 3 and 4 has already been directed to the discharge unit 5 in the sheet feeding direction (the arrow direction in FIG. 1).
On the other hand, the second sheet 6b reaches between the transmission sensor 8 and the reception sensor 9, and a reception signal is collected as the sheet whose output is being detected by the sheet thickness detection unit (S105). The collection signal is output to the CPU 11. The paper thickness comparing unit 13 compares the raw output of the second sheet 6b with the threshold value (normal range R2) relating to the first sheet 6a from the memory unit 15 (S106). ).

In the comparison process, first, the ultrasonic level that is the detection result of the thickness of the second sheet (corresponding to N = 2) is the upper threshold value of the normal range R2, {(N−1) th sheet. It is determined whether or not the ultrasonic level exceeds + α} (S106). When it is determined that it does not exceed, the process proceeds to the next step (S107).
On the other hand, when it is determined that the sheet has exceeded, the second sheet 6b is determined to be out of the normal range R2 as a thin sheet detection (S106), and the drive system related to sheet conveyance is shut off, and the conveyance path The drive unit such as 7 stops. The paper sheet 6b is discharged from the conveyance path 7 (S110).

Next, it is determined whether or not the second sheet 6b has reached the lower limit threshold value of the normal range R2, {(N−1) th ultrasonic level−β} (S107). When it is determined that it has reached, the process proceeds to the next step (S108).
On the other hand, when it is determined that the sheet has not been reached, the second sheet 6b is determined to be out of the normal range R2 as a thick sheet detection (S107), the drive system related to sheet conveyance is shut off, and the conveyance path The drive unit such as 7 stops. The paper sheet 6b is discharged from the conveyance path 7 (S111).

While the processing of the second sheet 6b is completed, the presence / absence of the next sheet 6c (third sheet) is checked (S108). If it is determined that there is, the process returns to the step waiting for the sheet 6c (S105). . If it is determined that there is no, the transport process ends (S109).

DESCRIPTION OF SYMBOLS 1: Paper thickness detection apparatus, 2: Paper feeding part, 5: Discharge part, 6: Paper sheet, 7, Conveyance path 8: Paper thickness detection part, 9: Ultrasonic wave generation part, 10: Ultrasonic wave reception part 11: Center Processing unit (CPU), 12: threshold value calculation unit,
13: Paper thickness comparison unit, 14: Paper sheet conveyance control unit, 15: Memory unit

Claims (16)

A paper thickness detection unit arranged in a paper path for detecting and outputting a paper thickness; a threshold value calculation unit for calculating a threshold based on the detection output of the paper thickness detection unit; and the detection output And a paper thickness comparison unit that compares the threshold value, and a paper sheet conveyance control unit that controls the continuation or stop of conveyance of the paper sheet based on the comparison result of the paper thickness comparison unit, Based on the comparison result of the paper sheet detection output of the paper thickness detection unit with the threshold value of the paper sheet that has passed through the paper thickness detection unit immediately before, in the paper sheet transport control unit, the paper thickness detection unit A paper thickness detecting device that controls conveyance of a paper sheet. The threshold value includes an upper threshold value and a lower threshold value, and the upper threshold value and / or the lower threshold value can be appropriately changed. The paper thickness detection device according to claim 1. 2. The paper sheet conveyance control unit issues a control command to continue conveyance of the paper sheets when the detection output is within the threshold value as a result of the comparison. Paper thickness detector. When the detection output exceeds the upper limit threshold value as a result of the comparison, the paper sheet conveyance control unit determines that the paper sheet is thin and controls to stop conveyance of the paper sheet. 2. The paper thickness detection device according to claim 1, wherein the command is issued. When the detection output does not reach the lower limit threshold value as a result of the comparison, the paper sheet conveyance control unit determines that the paper sheet is thick paper and performs control to stop conveyance of the paper sheet. 2. The paper thickness detection device according to claim 1, wherein the command is issued. The paper thickness detection device according to claim 1, wherein the paper thickness detection unit includes a sensor including a sensor generation unit and a sensor reception unit. The paper thickness detection apparatus according to claim 1, wherein the paper thickness detection unit includes an ultrasonic sensor including an ultrasonic wave generation unit and an ultrasonic wave reception unit. A paper thickness detection unit arranged in a paper path for detecting and outputting a paper thickness; a threshold value calculation unit for calculating a threshold based on the detection output of the paper thickness detection unit; and the detection output And a paper thickness comparison unit that compares the threshold value, and a paper sheet conveyance control unit that controls the continuation or stop of conveyance of the paper sheet based on the comparison result of the paper thickness comparison unit, Based on the comparison result with the threshold value calculated by the combination of a plurality of paper sheets that have already passed through the paper thickness detection unit, the paper sheet detection output of the paper thickness detection unit, A paper thickness detection apparatus that controls the conveyance of a paper sheet of the paper thickness detection unit. A paper thickness detection unit arranged in a paper path for detecting and outputting a paper thickness; a threshold value calculation unit for calculating a threshold based on the detection output of the paper thickness detection unit; and the detection output And a paper thickness comparison unit that compares the threshold value and a paper sheet conveyance control unit that controls the continuation or stop of conveyance of the paper sheet based on the comparison result of the paper thickness comparison unit,
Based on the comparison result between the detection value of the paper sheet of the paper thickness detection unit and the threshold value of the paper sheet that has passed through the paper thickness detection unit immediately before, in the paper sheet transport control unit, the paper thickness detection unit A paper thickness detection method characterized in that conveyance control of paper sheets is performed. The threshold value includes an upper threshold value and a lower threshold value, and the upper threshold value and / or the lower threshold value can be appropriately changed. The paper thickness detection method according to claim 8. 9. The paper thickness detection according to claim 8, wherein when the detection output is within the threshold value as a comparison result, the paper sheet conveyance control unit issues a control command to continue conveyance of the paper sheet. Method. When the detection output exceeds the upper threshold value as a comparison result, the paper sheet conveyance control unit determines that the paper sheet is thin and issues a control command to stop the conveyance of the paper sheet. The paper thickness detecting method according to claim 8, wherein the paper thickness is detected. When the detection output does not reach the lower limit threshold value as a comparison result, the paper sheet conveyance control unit determines that the paper sheet is thick paper, and issues a control command to stop the conveyance of the paper sheet. The paper thickness detecting method according to claim 8, wherein the paper thickness is detected. The paper thickness detection method according to claim 1, wherein the paper thickness detection unit includes a sensor including a sensor generation unit and a sensor reception unit. The paper thickness detection method according to claim 8, wherein the paper thickness detection unit includes an ultrasonic sensor including an ultrasonic generation unit and an ultrasonic detection unit. A paper thickness detection unit arranged in a paper path for detecting and outputting a paper thickness; a threshold value calculation unit for calculating a threshold based on the detection output of the paper thickness detection unit; and the detection output And a paper thickness comparison unit that compares the threshold value, and a paper sheet conveyance control unit that controls the continuation or stop of conveyance of the paper sheet based on the comparison result of the paper thickness comparison unit, Based on the comparison result with the threshold value calculated by the combination of a plurality of paper sheets that have already passed through the paper thickness detection unit, the paper sheet detection output of the paper thickness detection unit, A paper thickness detection method, wherein the paper thickness detection unit performs conveyance control of a paper sheet.