JPS6270146A - Device for monitoring condition of conveyance of document - Google Patents

Abstract

PURPOSE:To precisely monitor the condition of conveyance of documents even if variations in speed occur in a document conveying mechanism, by providing a speed detecting section for delivering count pulses in synchronization with the conveying speed. CONSTITUTION:Both first and second sensors 13, 14 normally turn on lower light emitting elements 13', 14', and therefore, upper light receiving elements 13'', 14'' are turned on by receiving light from the lower light emitting elements 13', 14'. When a documents 10 arrives, the light from the light emitting elements are shaded so that the light receiving elements 13'', 14'' are turned off, and therefore, such variations are detected as detection signals 23, 24. A conveying mechanism 41 is provided therein with a speed detecting section 42. A counter 52 counts cout pulses 48 during an output signal from a flip-flop circuit 35 being at its high level, and computation is made to obtain a bias value in accordance with the thus counted value. Thereby, it is possible to obtain count pulses corresponding to the conveying amount of documents, precisely, even if variations in speed occur in the document conveying mechanism, unless a slip or the like occurs between the documents and the document conveying mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a form conveyance state monitoring device that quantitatively monitors the form conveyance state.

[Conventional technology]

A device called an optical character reader (OCR), which reads characters and figures written on forms, is widely used to automate the manual processing of data written on forms into computers and the work of sorting forms. ing.

By adding a conveying device to the OCR to automatically feed documents in sequence, it is possible to speed up and fully automate the document reading process.

What is required of such a conveyance device is to feed the form to the OCR at a predetermined timing and in a predetermined posture. For example, if a form is sent to the OCR in a significantly oblique position compared to its normal orientation, it may become impossible to read or an error may occur in the reading.

Therefore, a process is taken to monitor the state of conveyance of the form, find a form that is skewed, and remove it or correct its orientation.

FIG. 3 is a block diagram of a conventional form transport state monitoring device.

The form 10 is conveyed in the direction of arrow 12 on an endless belt type form conveyance mechanism 11. Two sets of transmission type optical sensors 13 and 14 are provided on the sides of this conveyance path. Further, at the rear of the conveyance path, a form processing device 16 and a CR 17 for removing significantly skewed forms are arranged.

Here, if we pay attention to the front edge 10a of the form 10 in the conveyance direction, this edge is 0CR1 while facing perpendicularly to the conveyance direction 12.
7 is required. However, for some reason, the front m1oa of the form may be oblique with respect to the transport direction, as indicated by the broken line 10'. This state is called skewing of the form 10, but as long as the skew is less than a certain value, there is no problem in reading the 0CR17. However, if the number of cases exceeds that, it is necessary to take measures such as removing the form 10 from the conveyance path.

For this purpose, the outputs of the two sets of sensors 13 and 14 are processed, for example, as follows.

Each transmission type sensor has a light source on the upper side and a light receiving element on the lower side, and when a form passes between them and blocks the light from the light source, the light receiving element detects the change. It is a type sensor.

The outputs of the two sets of sensors 13, 14 are sent to the gate 21. A separate reference clock signal 22 is input to this gate 21 . The front edge 10a of the form 10 is the first sensor 1
3, this gate 21 is opened by the detection signal 23 of the first sensor 13 and the reference clock signal 22 is outputted to the counter 26. From this point on, the counter 26 starts counting the clock signal 22.

Thereafter, the leading edge 1 of the form 10 is placed at the second sensor 14.
When 0a arrives, the gate 21 is closed by the detection signal 24 of the second sensor 14. As a result, the counter 26 is
It indicates a certain count value and then stops the counting operation.

The determination circuit 27 reads this value and detects whether the first sensor 13 and the second sensor 14 are connected to each other when the form 10 is in a normal posture.
Compare with the count value when passing between. This count value may be stored in advance in a memory or the like within the determination circuit. If the form 10 is skewed, the count value at that time will always be larger than the normal count value. If this difference is greater than or equal to a certain value, the determination circuit 27 outputs a form removal command signal 28 to the form processing device 16.

As a result, the form 10 is removed from the conveyance path.

In addition to the configuration explained in this figure, there is also a cumulative skew amount detection method, such as installing two more sets of sensors as shown in the figure on opposite sides of the conveyance path and comparing these detection signals. Are known.

[Problem to be solved by the invention 3 In the document conveyance state monitoring device as explained above,
If the frequency of the reference clock signal 22 inputted to the gate 21 is increased, the detection accuracy can be further improved.

However, if a speed fluctuation occurs in the form transport mechanism 11, an error may occur in the count value. That is,
If the conveyance speed decreases below the set value, the count value of the counter 26 will be larger than the true value. Therefore, the form 10 may be considered to be skewed even though it is not. On the other hand, if the conveyance speed is higher than the set value, the form will not be removed even if it is skewed.

The present invention has been made with attention to the above points, and provides a document conveyance state monitoring device that can accurately and quantitatively monitor the general conveyance state of documents without being affected by fluctuations in conveyance speed. The purpose is to

[Means for solving problems]

The document conveyance state monitoring device of the present invention includes a document conveyance mechanism that conveys the document along a conveyance path, a first sensor that detects the arrival of the document on this conveyance path, and a device located behind the first sensor. a second sensor that detects the arrival of the form, and a monitoring unit that monitors the movement of the form from when the form is detected by the first sensor until it is detected by the second sensor, The conveyance mechanism is provided with a speed detection section that outputs count pulses synchronized with the conveyance speed, and the monitoring section detects the count pulse output from the speed detection section after the first sensor detects the arrival of the form. The second sensor starts counting and stops counting when the second sensor detects the arrival of a form.

[Effect]

In this way, if the count pulses are counted in synchronization with the transport speed of the document transport mechanism, the relationship between the count value and the transport amount will not change even if the speed increases or decreases.

Therefore, it is possible to quantitatively monitor the transportation state of the form with high precision.

〔Example〕

(Description of Blocks) FIG. 1 is a block diagram showing an embodiment of a form conveyance state monitoring device of the present invention.

This device has the same two
A set of transmissive optical sensors 13, 14 is provided.

In both the first sensor 13 and the second sensor 14, the lower light emitting elements 13' and 14' are always lit, and the upper light receiving elements 13'' and 14'' receive this light and are turned on. ing. These light emitting elements 13', 14' and light receiving elements 13'',
When the form 10 arrives during the period 14'', the light from the light emitting element is cut off and the light receiving element is turned off, and the change is taken out as the detection signal 23, 24.

The form conveyance mechanism is of an endless belt type similar to the one in FIG.

In order to process this detection signal, amplifiers 31 and 32, an OR circuit 33, an AND circuit 34, and a flip-flop (
F/F) circuit 35 is provided.

The amplifiers 31 and 32 are for amplifying and shaping the detection signals 23 and 24 of the first sensor 13 and the second sensor 14, respectively. The output signals of both amplifiers 31 and 32 are input to an OR circuit 33 and an AND circuit 34, the logical sum of which is input to the set terminal 35' of the flip-flop circuit 35, and the logical product is input to the reset terminal of the flip-flop circuit 35. 7)
The terminal 35' is configured to be manually connected.

On the other hand, the form conveyance mechanism 41 is provided with a speed detection section 42 . This speed detection section 42 includes a so-called low-return encoder 44 directly connected to the drive shaft 43 of the endless belt 40;
It consists of a transmission type optical sensor 46 attached facing the slit 45 and an amplifier 47.

The low-resolution encoder 44 has radial slits 45 arranged at equal intervals, and has a known configuration that is often used to measure rotation speed and rotation angle. Transmissive optical sensor 4
6 may have the same configuration as the sensors 13 and 14 that detect the arrival of the form 10. Therefore, each time one slit 45 of the low-return encoder 44 passes between the light emitting element 46' and the light receiving element 46"' of this sensor 46, the light receiving element 46' is turned on once and a signal is output. Ru.

The signal is amplified and shaped by an amplifier 47.

A pulse-like output signal is obtained from this speed detection section 42. In the present invention, this output signal is used as count pulse 4.
I'll call it 8.

The output signal of the flip-flop circuit 35 and this count pulse 48 are input to an AND circuit 51, and the logical product 51' is connected to a counter 52. This counter 52 is called a monitoring section in the present invention.

(Operation of the device) The device having the above configuration operates as follows. FIG. 2 is a timing chart of signals of each part of this device. first,
Focusing on the detection signal 23 of the first sensor 13, this signal is turned off from time t1 to time t3 and turned on before and after that, as shown in FIG. 2a. That is, the leading edge of the form 10 reaches the first sensor 13 at time t1, and then the trailing edge of the form 10 reaches the first sensor 13 at time t3.
This means that you have passed 3.

As shown in the figure, the second sensor changes from on to off at time t2, delayed by time T from the operation of the first sensor, and from off to on at time t4.

Amplifiers 31 and 32 are so-called inverting amplifiers, and output signals of opposite polarity to a and b in the figure, respectively, as shown in c and d in the figure. Each signal below is ＼＼L/S/l/“H”
The level is expressed as "L".

When the output signals of the two amplifiers 31 and 32 are input to the OR circuit 33, the logical product is calculated at time t1, as shown in e in the figure.
goes from "L" to "H" at time t4, and changes from "H" to "P" at time t4.
°''. Also, these are the contents of the AND circuit 34
, the logical sum changes from 'L' to 'H' at time t2.
The content changes from "H" to L'" at time t3.

Here, when the set input terminal 35' of the flip-flop circuit 35 becomes "H" at time t1, its output becomes "H" at that time.Furthermore, at time t2, the reset input terminal 35' becomes "H". , the output signal becomes “H” again.
and return to L” (g in the same figure).

The AND circuit 51 performs a logical product of the output signal of the flip-flop circuit 35 and the count pulse 48 (l[lh).

Since this count pulse 48 is synchronized with the rotational speed of the form transport mechanism, the pulse does not necessarily have a constant period during the time T. However, when a certain amount of documents are conveyed, a number of pulses proportional to the amount of conveyance are always applied to the ant circuit 51 (FIG. 1).

The counter 52 counts the count pulses 48 while the output signal of the flip-flop circuit 35 becomes H'',
Based on this, the amount of skew is calculated.

As a result, as long as no slip or the like occurs between the form and the form transport mechanism, it is possible to obtain count pulses that accurately correspond to the conveyance amount of the form even if speed fluctuations occur in the form transport mechanism. Therefore, when a form is skewed, the amount of skew can be detected with high accuracy.

[Modified example]

The document conveyance state monitoring device of the present invention is not limited to the above embodiments.

Although an example is shown in which a transmissive type sensor is used as the sensor, it may be a reflective type sensor, a contact type sensor, or the like.

Further, although an example is shown in which only two sets of sensors are used, several sets of sensors may be used to ensure reliable operation.

In addition, the form conveyance mechanism is not an endless belt type (a roller type or the like can also be adopted).

Furthermore, as the speed detection section, various mechanisms such as an electromagnetic resolver may be employed in addition to the low-resolution encoder.

It goes without saying that the signal processing circuit of each sensor may be replaced with a known circuit configuration having a similar function.

〔Effect of the invention〕

The document conveyance state monitoring device of the present invention described above is capable of accurately monitoring the document conveyance state even if speed fluctuations occur in the document conveyance mechanism, and detecting the amount of skew, etc. with high accuracy. It is.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the document conveyance state monitoring device of the present invention, FIG. 2 is a timing chart of its operation, and FIG. 3 is a block diagram showing an example of a conventional document conveyance state monitoring device. be. 10... Form, 13... First sensor, 14... Second sensor, 41... Form transport mechanism, 42... -Speed detection section, 52...Monitoring section. (Fig. 1, Fig. 2); ) j (g) F/F35 1-11-J----1111: (i; (i)

Claims (1)

[Claims] a form transport mechanism that transports the form along a transport path; a first sensor that detects the arrival of the form on this transport path; and a second sensor located behind the first sensor that detects the arrival of the form. and a monitoring unit that monitors the movement of the form from when the form is detected by the first sensor until it is detected by the second sensor, and the form transport mechanism has a counter that is synchronized with the transport speed. A speed detection unit that outputs a pulse is provided, and the monitoring unit starts counting the count pulse output from the speed detection unit after the first sensor detects the arrival of a form, and the second sensor starts counting the count pulse output from the speed detection unit. A form conveyance state monitoring device characterized by stopping counting when the arrival of a form is detected.