JP2680958B2 - Media overlap detection method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for detecting the repeated feeding of media in an apparatus for optically reading various information recorded on the media.

[0002]

2. Description of the Related Art FIG. 8 shows a part of a medium conveying path of a conventionally known optical reading apparatus, in which a medium 1 such as a sheet is arranged along a medium conveying path 2. Roller pair (3a, 3b), (4a, 4b), (5a, 5
It is conveyed in the direction of arrow 20 in the figure by b). Further, in the middle of the medium transport path 2, a traveling monitoring sensor 6 for detecting the medium 1 sucked into the medium transport path 2 includes a roller pair (3a, 3b) and a roller pair (4a, 4b). A medium stacking feed detection unit 7 is disposed behind the roller pair (5a, 5b) while being disposed between them.

The medium stacking feed detecting section 7 has a drive roller 8 rotated by a drive motor (not shown) and an arrow A in the figure according to the thickness dimension of the medium 1 interposed between the drive roller 8 and the drive roller 8. It has a two-sheet detection roller 9 and the like that can be displaced in the -B direction. In addition, as shown in FIG. 9 and the side view of FIG. 9 taken along the line YY of FIG.
Is connected to a rotary shaft 14a of a rotary potentiometer 14 via a support shaft 10, a lever 11, a support shaft 12, a cam disk 13, and the like.

More specifically, the rotary potentiometer 14 is fixedly mounted on a frame (not shown), and the cam disk 13 is mounted on the rotary shaft 14a so as to be integrally rotatable. Further, a brake shoe 19 for absorbing vibration is pressed against the outer peripheral surface of the cam disk 13, and a rotatable roller 15 is attached to the front surface side. The roller 15 is attached to the outer peripheral surface of the roller 15. 11
One end of is pressed by the biasing force of the coil spring 16. In addition, one end of the coil spring 16 is connected to the lever 1
It is hooked to a part 11 a of the No. 1 and the other end is hooked to the roller 15. On the other hand, an intermediate portion of the lever 11 is rotatably attached to the frame via a support shaft 12. In addition, the tip portion 11b beyond the portion where the two-sheet detection roller 9 is rotatably attached via the spindle 10.
Similarly, one end of a coil spring 17 is hooked on. The other end of the coil spring 17 is hooked on a pin 18 fixed to the frame and has a tensile force larger than that of the coil spring 16.

In the medium stacking feed detecting section 7 thus constructed, when the medium 1 is fed by the medium feeding system and sucked between the drive roller 8 and the two-sheet detecting roller 9, the thickness of the medium 1 is increased. The two-sheet detection roller 9 is shown in FIG. 8 and FIG.
It is pushed up by the dimension L in the arrow A direction. Then, at the same time, against the biasing force of the coil spring 17,
A force acts to rotate the lever 11 in the counterclockwise direction in the figure, and the lever 11 rotates in the counterclockwise direction with the support shaft 12 as a fulcrum. Further, when the lever 11 rotates, the rotary shaft 14a of the rotary potentiometer 14 is also rotated in the arrow C direction in FIG. 9, that is, the clockwise direction via the roller 15 and the cam disk 13. The rotation amount of the rotary shaft 14a is output from the rotary potentiometer 14 as an output voltage proportional to the displacement amount of the two-sheet detection roller 9, and the output voltage is sent to a detection circuit (not shown).

FIG. 11 shows an example of the output waveform at this time. As can be seen from FIG. 11, when the medium 1 is fed between the driving roller 8 and the two-sheet detecting roller 9, the time from the plunge time is reduced. With respect to the output voltage during 30 millisecond, the impact received by the two-sheet detection roller 9 appears as a vibration, and this vibration exceeds the slice level, that is, the judgment reference n sheets.
Here, in the case where the brake shoe 19 is not provided, as shown in FIG.
A large vibration exceeding the number of sheets will be generated. But,
In this medium stacking feed detection unit 7, the brake shoe 19 is pressed against the outer peripheral surface of the cam disk 13 to apply a load, and vibration is suppressed by this load, so only one medium 1 was conveyed. In some cases, it will be below the slice level after about 30 millisecond. Therefore, after the change appears in the output voltage from the rotary potentiometer 14, about 3
If the output voltage after 0 millisecond is sampled for about 45 millisecond and compared with the judgment reference voltage,
It is possible to know with relative accuracy whether or not the medium 1 has been overlaid, and conventionally, this determination method has been generally used.

[0007]

However, in the structure of the above-mentioned conventional medium overlap feed detecting portion 7, the cam disk 1 is used.
The frictional force of the brake shoe 19 provided in contact with the No. 3 is greatly influenced by many factors such as temperature, humidity, and changes in the sliding surface state. Therefore, the medium 1 in the optical reading device is
It is unreasonable when the medium 1 is thin and fine load fluctuations are picked up and controlled, as in the case of detecting the overlapped feeding. FIG.
3 indicates this uncertain output voltage. When the frictional force of the brake shoe 19 is large, the output voltage level 21a when one sheet is fed and the output voltage level 21b when two sheets are fed are both. Slice level 22 and below,
Even if two sheets are fed, it cannot be detected. As described above, the conventional medium overlap feeding detection method has a problem in that it lacks reliability.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a medium overlap feeding detection system which improves detection accuracy and is highly reliable.

[0009]

In order to achieve the above object, the medium overlap feeding detection method according to the present invention is a medium overlap feeding detection method for detecting the overlap feeding of media in a medium conveyance path. A detection roller that is displaced according to the thickness of the medium inside it, an output means for obtaining an output voltage proportional to the amount of displacement of the detection roller, and a timer means for counting a certain time after the detection roller detects the medium. After counting a fixed time by the timer means, the peak value of each peak side and the valley side of the output waveform of the output means is periodically sampled a plurality of times, and the data sampled by the sampling means is averaged. Output data from the calculation means and the output means when the detection roller is idly rotated without feeding the medium in advance is obtained, and the average value obtained by the calculation means is calculated. And a slice level corresponding to the continuous amount of the medium and the slice level corresponding to the continuous amount of the medium are compared to determine the overlapped feeding of the medium. .

[0010]

According to the present invention as described above, when the thickness of the medium is detected by the detection roller, a predetermined time after the detection roller detects the medium by the timer means is counted,
After that, since the peak value of each of the peak side and the valley side of the output waveform of the output means is periodically sampled by the sampling means a plurality of times, the noise output waveform that appears at the amplitude immediately after the medium collides with the detection roller is captured. Instead, it becomes possible to fetch data in a stable state and perform arithmetic operations. In addition, the fact that the cycle of the amplitude of the detection roller when the medium collides with the detection roller is constant regardless of the thickness of the medium and the traveling speed, and the peak value of each of the peak side and the valley side of the amplitude output waveform is set to a plurality of values. By sampling once, it is possible to prevent the output waveform at the average value from being biased to the peak side or the valley side. Further, the output data from the output means when the detection roller is idly rotated without feeding the medium is obtained in advance, and the peak values of the peak side and the valley side of the vibration output waveform are sampled multiple times from the average value. Since the value obtained by subtracting the output data when the detection roller is idled and the slice level corresponding to the continuous amount of the medium are compared to determine the overlapped feeding of the medium,
Unnecessary components of the output data generated by the rotation of the detection roller itself can be removed from the average value of the sampled data, the comparison with the slice level can be stabilized, and the detection accuracy can always be stabilized.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 4 shows a part of a medium conveyance path of an optical reading device to which the medium overlap feeding detection method according to the present invention is applied, and FIG. 5 shows a detailed structure arranged in the middle of the medium conveyance path. 6 is a side view of the main part taken along the line XX of FIG. 8 to 10 are denoted by the same reference numerals as those in FIGS. 8 to 10.
The same as 0 is shown. 8 to 10 are different from the medium overlap feeding detection unit 27 shown in FIGS. 4 to 6 and the medium overlap feeding detection unit 7 shown in FIGS. 8 to 10.
Brake shoe 19 of the medium stack feeding detection unit 7 shown in FIG.
Is not provided in the medium stacking feed detection unit 27 shown in FIGS. 4 to 6, and the other structures are the same.

Therefore, the medium stacking feed detecting unit 27
Then, the rotary potentiometer 1 when the medium 1 is detected
The output voltage waveform output from 4 is obtained as a naturally decaying waveform as shown in FIG.

FIG. 3 is a block diagram showing a signal processing circuit configuration of a medium overlap feed detection control system in the optical reading apparatus shown in FIG. In FIG. 3, the output signal of the rotary potentiometer 14 as an output means for generating an output voltage proportional to the displacement amount of the two-sheet detection roller 9 is passed through an amplifier 21 to an A / D (analog-digital) converter 22.
To the digital signal, and then input to the arithmetic circuit (CPU) 23 for processing. Here, a timer 24 is connected to the arithmetic circuit 23, and the output of the traveling monitoring sensor 6 can be input.

FIG. 1 is a flow chart showing the control procedure in the arithmetic circuit 23 for processing the output signal input from the rotary potentiometer 14, and FIG. 2 shows the running monitoring sensor 6 for detecting the timing of medium overlap feeding sampling. It is a figure explaining the output timing and the output timing of the rotary potentiometer 14. Therefore, FIGS.
A procedure for detecting the overlapped feeding of the medium 1 will be described with reference to FIGS. 1 and 2.

First, here, the length of the medium 1 handled by the optical reading device is 85 mm, and
Set the distance from the travel monitoring sensor 6 to the two-sheet detection roller to 9
It is set to 8.36 mm. Furthermore, medium 1
In the sampling of the overlapped feeding of two sheets, the two-sheet detection roller 9 is used as the medium 1
Is not immediately detected, but after about 30 millimeters, that is, after about 128.36 millimeters from the travel monitoring sensor 6, sampling is performed for about 55 millimeters while advancing.

Here, the reason why the two-sheet detecting roller 9 detects the medium 1 and immediately after 30 mm has passed without sampling, is as follows. That is, when the medium 1 is sent between the drive roller 8 and the two-sheet detection roller 9,
As shown in FIG. 7, the impact force at this time causes the two-sheet detection roller 9 to largely bounce (amplify), and the peak of the second amplitude appears after advancing by 30 millimeters. Therefore, the amplitude associated with the impact force at the first time is removed and the movement of the two-sheet detection roller 9 is detected in a stable state. Since the amplitude is constant irrespective of the period of the medium, the medium thickness, and the medium traveling speed, a peak appears at almost the same position every time the medium 1 is sent.
When sampling is performed after the time to advance millimeters,
The detection operation can proceed in a stable state with noise removed.

Further, in this embodiment, the sampling is
Over the course of about 55 millimeters of media 1,
During this time, it is performed 16 times with a time pitch of 3 mm. This is the medium 1 in the optical reader here.
Assuming that the minimum specification is 85 mm and the outer circumference of the driving roller 8 is 49 mm, approximately 49 peaks (peaks and troughs) of the amplitude occur at a time pitch in which the medium 1 advances by 3 mm. This is because it can be divided 16 times by dividing by millimeters, that is, 49 ÷ 3≈16.

First, when the running of the medium 1 is started, the roller pairs (3a, 3b), (4a, 4b), (5a, 5b).
And the drive roller 8 is rotated (step ST1).
This is performed by rotating the drive roller 8 to sample and average the sensor output of two sheets of detection leads, that is, one rotation of the rotating roller for 16 times, and store this in a memory (not shown). In this case, the value at this time is set to XO, and the level when there is no medium 1 is set (step ST2). Next, in step ST3, the value is compared with the upper limit value (theoretical upper limit alarm value) TH0 when there is no medium 1, and if the value X0 is smaller than the upper limit value TH0, the process proceeds to step ST4, and if it is larger. Is a two-sheet detection adjustment error and step ST
After step 5, the process returns to step ST1 to perform sampling again. On the other hand, when the process proceeds to step ST4, the reading traveling mode is entered and the traveling of the medium 1 is permitted.

When the medium 1 is run and the medium 1 is detected by the running monitor sensor 6, the running monitor sensor 6 outputs an ON signal for the length of the medium 1, that is, 85 mm. Further, the timer 24 starts counting at the same time when the traveling monitoring sensor 6 detects the medium 1. On the other hand, the medium 1 that has passed through the traveling monitoring sensor 6 is 98.36.
When it advances by a millimeter, it reaches between the drive roller 8 and the two-sheet detection roller 9, pushes up the two-sheet detection roller 9 in the direction of arrow A in FIGS. 4 and 5, and this appears as the output voltage of the rotary potentiometer 14. Then, sampling is started after the time when the medium 1 advances by 128.36 millimeters after the timer 24 starts counting, that is, the time when the medium 1 advances by 30 millimeters after the output voltage of the rotary potentiometer 14 appears. Sampling is performed 16 times at a time pitch of advancing the medium 1 by 3 millimeters while advancing the medium 1 by 49 millimeters, and the overlap feed is detected (steps ST4, 6, 7, 8, 9). In this process, the medium 1 advances by 3 millimeters at a time pitch of 16
The second and the second detection levels are read and sampled (step ST6), and the sampled values E1 and E
2, E3, ..., E16 are averaged, and the average value Xn is obtained (step ST7). The difference between the averaged value Xn and the level value X0 when the medium 1 is not present (X
n−X0) is calculated, and this value is set to X (step ST
8). Further, this value X is compared with a constant (slice value) THn corresponding to the continuous amount of each medium 1 (step ST9),
If it is smaller than the constant THn, it is judged that only one medium 1 has been sent, the process returns to step ST4, and the conveyance of the next medium 1 is permitted. On the other hand, if the value X is larger than the constant THn, it is judged that there are two or more mediums 1 that have been sent, and the process proceeds to step ST10 to notify with a buzzer or the like and wait for alarm processing due to heavy running, and further processing. After that, the process returns to step ST1 and the same procedure is repeated.

Therefore, according to this medium overlap feed detection method, the cycle of the amplitude of the vibration when the medium 1 starts to enter between the two-sheet detection roller 9 and the drive roller 8 is
Paying attention to the fact that it is constant regardless of the medium thickness and medium traveling speed, the peak value of the vibration output is set a plurality of times (16
By comparing the average value Xn at the time of sampling and the slice level value THn, it is possible to detect the running of two media 1, and therefore the stability is always excellent.

Although the present invention has been described with reference to the above embodiment, it is not limited to the structure of this embodiment, of course.
The distance from the travel monitoring sensor 6 to the two-sheet detection roller 9,
Of course, the sampling period and the number of times may be other than this. Further, although the rotary potentiometer 14 is used as the means for outputting the output voltage proportional to the displacement amount of the two-sheet detecting roller 9, the other means may be used.

[0022]

As described above, according to the medium overlap feeding detection system of the present invention, the output signal of the output means has its vibration stabilized by the brake shoe as used in the conventional detection system. Since it is not detected later but is obtained by averaging the data sampled for a certain period, it is possible to obtain the data without being influenced by external factors such as temperature and humidity. Further, since the timer means starts sampling after a lapse of a certain time, it is possible to stably capture data without capturing the noise output waveform generated when the medium collides with the detection roller. In addition, the fact that the cycle of the amplitude of the detection roller when the medium collides with the detection roller is constant regardless of the thickness of the medium and the traveling speed, and the detection roller was idled without feeding the medium in advance. The value obtained by subtracting the output data when the detection roller is idling from the average value when the peak value of the peak side and the valley side of the vibration output waveform is sampled multiple times in advance. And the slice level corresponding to the continuous amount of the medium are compared to determine the overlapped feeding of the medium, so that the detection accuracy is always stable and the overlapped feeding can be detected with high reliability.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example of a procedure of a process of detecting overlapped feeding of media according to the present invention.

FIG. 2 is a diagram showing an output timing of a travel monitoring sensor and an output timing of a potentiometer.

FIG. 3 is a block diagram of a signal processing circuit configuration according to the present embodiment.

FIG. 4 is a schematic configuration diagram of a medium transport path of the present embodiment.

FIG. 5 is a structural diagram of a main part of a medium stack feeding detection unit of the present embodiment.

6 is a side view of the main part taken along line XX of FIG.

FIG. 7 is a potentiometer output waveform diagram during medium detection.

FIG. 8 is a schematic configuration diagram of a medium transport path in a conventional example.

FIG. 9 is a structural diagram of a main part of a medium stack feeding detection unit in a conventional example.

10 is a side view of an essential part taken along the line YY of FIG.

FIG. 11 is a diagram showing a conventional potentiometer output waveform state.

FIG. 12 is a diagram showing a potentiometer output waveform state for explaining a conventional problem.

FIG. 13 is a diagram for explaining a potentiometer output waveform state when a conventional brake shoe is not provided.

Claims (1)

(57) [Claims] 1. A medium overlap feed detection method for detecting overlap feed of media in a medium convey path, comprising: a detector roller that is displaced according to the thickness of the medium inside the medium convey path; and a displacement amount of the detector roller. Output means for obtaining an output voltage proportional to, timer means for counting a fixed time after the detection roller detects the medium, and the output means after counting the fixed time by the timer means Sampling means for periodically sampling the peak value of each of the peak side and the valley side of the output waveform of the above, an arithmetic means for averaging the data sampled by the sampling means, and the detection without sending the medium in advance. Output data from the output means when the roller is idled is obtained, and the detection is performed from the averaged data obtained by the arithmetic means. The value obtained by subtracting the output data when the roller is idled,
A medium overlap feed detection method, comprising: a determination unit that compares the slice level corresponding to the continuous amount of media to determine the medium overlap feed.