JPH04160688A - System for detecting superposed feeding of cutform media - Google Patents

Abstract

PURPOSE:To improve the linearity of an output voltage linearly proportonal to the displacement variable of a detection roller and to remove the dispersion of an output voltage change against the fixed displacement value of the detection roller by detecting the displacement variable of the detection roller corresponding to the thickness of a cutform by means of phase comparison with reflected light. CONSTITUTION:When a cutform medium 15 is sent to the detection roller 5a, the roller 5a is displaced only by the thickness of the medium 15 and a reflection plate 26 is rotated in proportion to the displacement variable. An output from a sensor 29 oppositely arranged through the plate 26 is compared with a reference value by a phase comparator 32 and an output from the comparator 32 expresses the displacement variable of the voltage linearly proportional to a phase difference. Consequently, the linearity of the output voltage linearly proportional to the displacement variable of the roller 5a can be improved and the dispersion of the output voltage change to the fixed displacement variable of the roller 5a can be removed. Thereby, an adusting circuit and adjusting work for correcting the dispersion can be omitted and the influence of a peripheral magnetic field can be removed.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for detecting overlapping feeding of cut media in an optical reading device that optically reads various information recorded on a form. .

<Prior Art> FIG. 3 is a schematic layout diagram showing an example of a conventionally known optical reading device.

In this optical reading device, a plurality of roller pairs (3a, 3b>, (4A, 4B)) are provided between the hopper 1 and the stacker 2.
, (4a, 4b), (5a.

5b), (6a, 6b), (7a, 7b), (8a, 8
b), (9a, 9b), and (10a, 10b) are provided, and the medium transport system 11
In the middle of the process, there is a media separator w412, a reading unit 13. A medium overlapping feed detection section 14 is provided.

In this optical reading device, the cut media 15 before being read is set in a hopper 1''2, and is sucked into the media conveying system one by one by a suction roller 16. It has become. On the other hand, two or more of the cut media 15 sucked into the medium conveying system 11 by the suction roller 16 pass through the reading unit 13.
In order to prevent the media from being sucked into the side, the media separating mechanism 12 performs a separating operation on the cut media 15 and sends them one by one to the reading unit 13 side.Furthermore, after being read by the reading unit 13, the media stacking detection unit 14 It is designed to be carried out to the stacker 2 through the. In addition, the medium overlapping feed detection unit 14
In this case, even though the cut media 15 is supposed to be separated one by one through the media separation mechanism 12, the separation operation is not sufficient and two or more sheets are stacked and transported. It is possible to detect this and double check for overlapping feed.

FIG. 4 shows the detailed structure of the conventional medium overlapping feed detection section 14. As shown in FIG. In FIG. 4, the same reference numerals as in FIG. 5 indicate the same components as in FIG.

In the figure, a pair of rollers (5a, 5b) of the medium conveyance system 11 are arranged in the medium overlapping feed detection section 14, separated above and below the path through which the cut medium 15 passes. Of these, the roller 5b is used as a drive roller (hereinafter referred to as the "drive roller 5b") that is rotationally driven by a drive motor (not shown), and the roller 5a is used as a drive roller (hereinafter referred to as "drive roller 5b"), and the roller 5a is used as a drive roller (hereinafter referred to as "drive roller 5b"), and the roller 5a is used as a drive roller (hereinafter referred to as "drive roller 5b"). The detection roller (
Hereinafter, this roller 5a is used as a "detection roller 5a." Further, the detection roller 5a is connected to the support shaft 1.
7. It is attached to a rotating shaft 19a of a rotary potentiometer 19 via a lever 18.

More specifically, the rotary potentiometer 19 is attached to the medium running reference surface 20a of the frame 20 via a bracket 21 and screws 22. Moreover, one end side of the lever 18 is fixed to the rotating shaft 19a of the rotary potentiometer 19 so as to be rotatable therewith. On the other hand, the coil spring 23 is engaged with the other end of the lever 18, and the entire lever 18 is biased to rotate clockwise in FIG. 4 by the biasing force of the coil spring 23. ing. In addition, a detection roller 5a is rotatably attached to the intermediate portion of the lever 18 via a support shaft 17, and the rotational bias of the lever 18 brings the detection roller 5a into pressure contact with the drive roller 5b. ing.

The rotary potentiometer 19 uses a Hall element, exhibits an output voltage according to the amount of rotation of the rotary shaft 19a, and is generally well known.

In the medium overlapping feed detection unit 14 configured as described above, the cut medium 15 is fed from the direction of arrow B in FIG. 4 by the medium conveying system 11 and is sucked between the roller pair (5a, 5b). Then, the detection roller 5a is pushed up in the direction of arrow A in FIG. 4 due to the thickness of the cut medium 15. At the same time, a force acts to rotate the lever 18 or the rotating shaft 19a counterclockwise in the figure against the biasing force of the coil spring 23, using the rotating shaft 19a as a fulcrum. Rotate in this counterclockwise direction. In this case, this fourth
Since the amount of displacement in the direction of arrow A in the figure corresponds to the rotation angle of the rotating shaft 19a, this rotation appears as an output voltage of the rotary potentiometer 19, and this output voltage is sent to a detection circuit (not shown).

On the other hand, in the detection circuit, as shown in FIG. 5, the output voltage obtained from the rotary potentiometer 19 when only one cut medium 15 runs (waveform shown by a solid line in the figure), and the output voltage obtained when two or more cut media 15 run Output voltage (
A slice level voltage is set in advance as a signal for determining the waveform shown by the broken line in the figure. and,
The output voltage from one rotary potentiometer is compared with the slice level voltage, and if the voltage does not exceed the slice level voltage, it is determined that only one piece of the cut medium 15 has been run, and if it has exceeded it, it is determined that multiple sheets have been fed. are doing.

In addition, after the cut medium 15 passes, the coil spring 23
Due to the biasing force, the lever 18 and the rotating shaft 1a rotate back in the clockwise direction in FIG. 4, and the detection roller 5a
Waits for the next cut medium] 5 to be brought into contact with the drive roller 5b.

<Problem to be solved by the invention> However, the conventional medium overlapping feed detection unit 14 described above
Since the operating principle of the rotary potentiometer 19 uses a Hall element, the linearity of the linearity of the proportional relationship of the output voltage to the rotation angle of one rotary potentiometer, that is, the amount of displacement of the detection roller 5a, varies. Figure 6 (a) shows the variation in the proportional relationship linearity of the output voltages.
).

□ Also, the variation in output change with respect to a constant rotation angle of the rotary potentiometer 19, that is, the detection roller 5a
The variation in output voltage change for a certain amount of change is also the sixth factor.
The size increases as shown in Figure (b). For this reason, there was a problem that the comparison was difficult and the detection accuracy was lowered. In addition,
An adjustment circuit and an adjustment operation are required to correct these variations, resulting in a problem of high cost.

Furthermore, since the rotary potentiometer 19 uses a Hall element, it is susceptible to the influence of surrounding magnetic fields and is difficult to handle, and if not properly managed, the detection accuracy may be reduced.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a method for detecting overlapped feeding of cut media that can improve detection accuracy and reduce costs.

Means for Solving the Problem> In order to achieve the above object, according to the cut medium overlapping feed detection method according to the present invention, a detection roller that is displaced according to the thickness dimension of the cut medium in the medium conveyance system; , a sensor consisting of a reflector that is rotated according to the amount of displacement of the detection roller, a light emitter and a light receiver that are fixed at positions optically facing each other with the reflector in between, and a sensor that drives the light emitter. an oscillator to
a phase adjustment circuit that adjusts the phase of the oscillator output when the cut medium is not present to the phase when the oscillator output is reflected from the light emitter by the reflector and returned to the light receiver; a phase comparison circuit that outputs a voltage that is linearly proportional to the phase difference with the output from the phase adjustment circuit; and a phase comparison circuit that outputs a voltage that is linearly proportional to the phase difference with the output from the phase adjustment circuit, and overlaps feeding of the cut medium by comparing the output voltage from the phase comparison circuit with a predetermined slice level. A that detects
/D converter.

<Operation> According to this configuration, when a cut medium is sent to the detection roller portion, the detection roller is displaced by the thickness of the cut medium, and the reflection plate is rotated in proportion to this displacement amount. Ru. Then, the output from the sensor consisting of a light emitter and a light receiver arranged opposite each other through this reflector is compared with the output from the light emitter in a phase comparator circuit, and the output from this phase comparator circuit is converted into a phase difference. It appears as a linearly proportional amount of voltage displacement. Also,
By comparing this output voltage with the slice level voltage, it is possible to detect whether or not the cut medium has been fed in duplicate.

This improves the linearity of the output voltage, which is linearly proportional to the amount of displacement of the sensing roller, and eliminates variations in the output voltage with respect to a constant amount of displacement of the sensing roller. Therefore, it is possible to eliminate the adjustment circuit and adjustment work for correcting these variations, which were conventionally required, and at the same time, it is possible to eliminate the influence of the surrounding magnetic field.

<Example> Hereinafter, an example of the present invention will be described in detail using the drawings.

FIG. 1 shows one embodiment of the present invention, and schematically shows the configuration of a portion corresponding to the medium overlapping feed detection section 14 shown in FIG. 3. In FIG. In FIG. 1, the same reference numerals as in FIGS. 3 and 4 indicate the same components as in FIGS. 3 and 4.

In the medium overlapping feed detection section 14, a pair of rollers (5a, 5b) of the medium transport system 11 are arranged separately above and below the medium transport system 11 through which the cut medium 15 passes. Of these, the roller 5b is used as a drive roller 5b which is rotationally driven by a drive motor (not shown) in the same way as in the conventional structure shown in FIG. It is used as a detection roller 5a that is displaced in the A direction>. Further, the detection roller 5a is rotatably attached to a lever 18 via a support shaft 17.

More specifically, the lever 18 is rotatably attached to the medium traveling reference surface 20a of the frame 20 via a support shaft 25. In addition to the support shaft 17, a coil spring 23 is attached to one end of the lever 18. The entire lever 18 is urged to rotate in the clockwise direction in FIG. 1 by the urging force of the coil splinter 23, and this urging force normally brings the detection roller 5a into contact with the drive roller 5b. It has become. On the other hand, on the other end side of the lever 18, a laser reflecting plate 26 is movably sealed. In addition, a laser emitter 27 and a laser receiver 28 are optically arranged opposite to each other at front and rear positions with the laser reflector 26 in between.

Furthermore, the laser emitter 27 and the laser receiver 28 constitute two sensors, of which the laser emitter 2
7 is connected to an oscillator 30 that outputs a sine wave.

Then, in response to the sine wave output from the oscillator 30, coherent laser light corresponding to the sine wave output is reflected from the laser emitter 27 toward the laser reflection plate 26, and is refracted and reflected by the laser reflection plate 26 to receive the laser beam. vessel 28
It is designed to receive light.

On the other hand, the oscillator 30 is connected not only to the laser emitter 27 but also to a phase comparator circuit 32 via a phase adjustment circuit 31, so that all the sine wave output from the oscillator 30 is connected to the laser emitter 27.
7, and a part of the signal is input to the phase comparator circuit 32 via the phase adjustment circuit 3]. Further, the output from the laser receiver 28 is input to this phase comparator circuit 32, and in this phase comparator circuit 32, the output that is input via the phase adjustment circuit 31 and the output from the laser receiver 28 are input. The phase difference is expressed as an output voltage having a linear proportional relationship. An A/D converter 33 is also connected to the phase comparison circuit 32.
The output voltage from this phase comparator circuit 32 is input to an A/D converter 33 that compares it with a predetermined slice level voltage, and a signal indicating whether the voltage exceeds the slice level voltage is digitally output. There is.

Next, FIG. 2 is a diagram explaining the principle of measuring the amount of displacement of the laser reflecting plate 26. Therefore, the detection operation of the medium overlapping feed detection section 14 of this embodiment will be explained with reference to the principle diagram shown in FIG.

First of all, the paper speed of the paper medium 15 targeted in this embodiment is 55 to 135 kg/rn'' (thickness 0.1 to
0°2 mm), and the laser emitter 2 used
The laser wavelength of 7 is 1 mm (oscillation frequency 300G
Hz). Further, it is assumed that the laser reflecting plate 26 completely reflects the light, and the reflectance is set to "-1".

When there is no cut medium 15 between the detection roller 5a and the drive roller 5b, that is, in the initial adjustment, the output Sl of the oscillator 30 and the output S3 from the phase adjustment circuit 31 are
．． The input S2 from the laser receiver 28 generally has the relationship shown in FIG. 2(a) (relationship of phase difference φ), but the relationship shown in FIG. The output S3 is set to the output S2 so that the relationship is zero.

In this state, the medium transport system 11 transports the cut medium 15 from the direction of arrow B in FIG.
, 5b), that is, when the cut medium 15 is sucked between the detection roller 5a and the drive roller 5b, the detection roller 5a of the cut medium 15 is pushed up in the direction of arrow A in FIG. At the same time, a force acts on the lever 18 to rotate it in the counterclockwise direction in the figure against the biasing force of the coil spring 23 using the support shaft 25 as a fulcrum, and the lever 18 moves towards the detection roller 5.
It rotates in this counterclockwise direction together with a. Then, the laser reflector 26 also rotates relative to the sensor 29, and the sensor 2
The distance to 9 changes.

As a result, as shown in FIG. 2(C), the phase adjustment circuit 3
The input S2 from the laser receiver 28 is delayed in phase by 2π/10 with respect to the output S3 from the laser receiver 28.

This phase difference is expressed by the phase comparison circuit 32 as output power having a linear proportional relationship, and this is input to the A/D converter 33. Then, the A/D converter 33 compares the output voltage from the phase comparator circuit 32 with a predetermined slice level voltage, and outputs a digital signal as to whether the voltage exceeds the slice level voltage. Then, this output is input to a control circuit (not shown), and it is determined whether only one sheet of the cut medium 15 has been run, or whether two or more sheets have been run.

In addition, after the cut medium 15 passes, the coil splinter 23
The lever 18 rotates back in the clockwise direction in FIG. 1 due to the biasing force, and waits for the next cut medium 15 to be sent by coming into contact with the detection roller 5a or the drive roller 5b.

Therefore, according to the cut medium overlapping feed detection method according to this embodiment, the detection roller 5 is adjusted according to the thickness of the cut medium 15.
By detecting the displacement amount of a by phase comparison with the reflected laser light, the linearity of the output voltage, which is linearly proportional to the displacement amount of the detection roller 5a, is improved, and the displacement amount of the detection roller 5a is improved. This eliminates variations in the output voltage change for a constant amount of displacement. This eliminates the need for an adjustment circuit and adjustment work for correcting these variations, which were conventionally required, and also eliminates the influence of surrounding magnetic fields.

Although the present invention has been explained using the above embodiment, it is of course not limited to the structure of this embodiment, and various changes in design may be made without departing from the gist of the present invention. be. For example, in the above embodiment, the paper speed is 5
5 to 135 kg / rn2 (thickness 0.1 to 02 mm) has a structure using a laser, but for materials with a thickness of 1 mm or more, such as corrugated paper, microwaves are used. Anything that is coherent is good.

<Effects of the Invention> As described above, according to the cut medium overlapping feed detection method according to the present invention, the linearity of the output voltage, which is linearly proportional to the displacement amount of the detection roller, is improved. With,
It is possible to eliminate variations in the output voltage change with respect to a constant displacement amount of the detection roller. As a result, it is possible to eliminate the adjustment circuit and adjustment work required in the past to correct these variations, and at the same time eliminate the influence of the surrounding magnetic field, improving detection accuracy and reducing costs. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a medium overlapping feed detection section to which an embodiment of the present invention is applied. FIG. 2 is a detailed explanatory diagram of the present invention. FIG. 3 is a schematic configuration diagram of a conventional optical reading device. Figure 4 is a schematic configuration diagram of a conventional medium overlapping feed detection section, Figure 5 is an explanatory diagram of the relationship between rotary potentiometer output voltage and slice level, and Figures 6 (a> and (b) are respectively It is a diagram for explaining problems when using a rotary potentiometer. 5a detection roller, 5b... drive roller, 11...
Medium conveyance system, 14 Medium overlapping feed detection unit, 15... Single sheet medium, 26... Laser reflection plate, 27 Laser emitter,
28. Laser receiver, 29. Sensor, 30. Oscillator, 31. Phase adjustment circuit, 32.. Phase comparison circuit, 33.
・A/D converter.

Claims (1)

[Scope of Claims] In a cut medium overlapping feeding detection method for detecting overlapping feeding of cut media passing through a medium conveyance system, a detection roller that is displaced according to a thickness dimension of the cut medium in the medium conveyance system. a sensor consisting of a light emitter and a light receiver fixed at optically opposing positions with the reflective plate in between; a sensor that drives the light emitter; a phase adjustment circuit that adjusts the phase of the oscillator output when the single-cut medium is not present to the phase when the oscillator output is reflected from the light emitter by the reflector and returned to the light receiver; a phase comparison circuit that outputs a voltage linearly proportional to the phase difference between the output of the phase adjustment circuit and the output of the phase adjustment circuit; A method for detecting overlapped media feeding, characterized by comprising an A/D converter for detecting overlapped feeding of media.