JPS623471B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a method for automatically determining whether characters, symbols, etc. on printing paper, etc. are recorded on the front side or the back side of the paper. This paper proposes a discrimination method that is accurate and easy to perform.

For example, when printing on passbooks used in banks, etc., when the passbook is inserted into the printing device, the printing position is automatically set.
The latest printing part recorded in the passbook is detected and the next printing position is determined.

FIG. 1 is a diagram of a bankbook recording surface to show an example of this, and timing marks T ₁ , T ₂ , T _{3 ,} . . . are printed in advance at a constant pitch along the side edges of the recording paper 1. The pitch of these timing marks is equal to the printed line spacing, and transaction details are printed between each timing mark. In the case of the figure, the areas between timing marks T ₁ and T ₂ and between T ₂ and T ₃ have already been printed, and the next printing will be between timing marks T ₃ and
It will start between _T4 . To automatically determine this, use a hyphen in the transaction date field.
H ₁ , H ₂ ... are used. That is, timing mark sensors TMS and hyphen mark sensors HMS are provided corresponding to the rows of timing marks T ₁ , T _{2 .} . . and the rows of hyphen marks H ₁ , H ₂ .
As shown in Figure 2, the light emitting element 2 illuminates the timing mark row and the hyphen mark row with a light spot,
The reflected light is detected. This relationship is shown in FIG. 3 when viewed in terms of detection signals. If recording paper 1 is now moved in the direction of the arrow and inserted into the printing section, the timing mark will appear as shown in the upper row of Figure 3.
Detection signals corresponding to T ₁₀ , T ₉ ... are generated. Then, when the detection signal _h2 of the first hyphen mark _H2 is output and the next timing mark signal _t2 is output, it is determined that up to the second printing line has already been printed, and a stop signal is issued. Stop the chart paper feed motor. It is sufficient that the line to be recorded is immediately in front of the print head at this time of stop; however, in devices where this is not the case, the position is corrected by further driving the motor to feed the recording paper a predetermined distance in a predetermined direction. .

By the way, when detecting a hyphen mark in this manner, the hyphen marks _H5 and _H6 previously recorded on the back side of the recording paper 1 may be mistakenly read as regular hyphen marks on the front side. In other words, it is sufficient that the ink density during printing is always constant, but in reality, the ink density gradually becomes thinner. Therefore, if the hyphen marks H ₅ and H ₆ on the back side are printed when the ink is new and dark, and the hyphen marks H ₁ and H ₂ on the front side are printed when the ink is thin, then paper 1 is white. If the paper is made of paper with good light transmittance, the hyphen marks H ₅ and H ₆ on the back side may be as dark or darker than the hyphen marks H ₁ and H ₂ on the front side, and may be visible from the front side. . The detection level of the hyphen mark is naturally set based on the hyphen mark on the front side with the lowest ink density, so if the hyphen mark on the back side is darker than the front side as shown above,
It will be read out as a mark recorded on the front side. For example, if the hyphen mark _H5 on the back side is read out as a regular mark, it will be printed with two lines skipped.

As described above, the present invention provides a method for accurately and easily determining whether the print is printed on the front side or the back side when printing is performed on both the front and back sides of printing paper. This is a proposal. In order to achieve this object, the present invention detects the reflected light or transmitted light of the light irradiated on the recording paper, and when the recording paper and the photodetector are moved relative to each other,
A method is adopted in which the difference in the slope of the output change of the photodetector is determined when the irradiation light passes through the boundary between the recording section and the non-recording section.

Next, the basic principle and embodiments of the present invention will be explained in detail. Figure 4 A shows a light-transmissive recording medium 1 such as white paper.
A hyphen mark or the like is printed on the back side B of the paper, so that a printed portion (print ink) 3 is attached thereto, and a single light beam 4 is irradiated from the front side. In such a case, the light hits the particles 5 constituting the paper 1 and is diffusely reflected, and the light appearing on the front side is diffusely reflected in each direction. That is, when viewed from the front side, the boundary between the printed portion 3 and the non-printed portion 6 appears blurred. Therefore, surface A
A photodetector S is installed on the side so that reflected light can be detected, and the detection output of the detector S is observed while moving the paper 1 relative to the detector S in the direction of the arrow. It becomes like this. In other words, due to diffuse reflection, the amount of reflected light at the boundary between the printed area 3 and the non-printed area 6 gradually changes with a gradient, so the detector output also rises and falls between sections 6' and 3'. is accompanied by a gentle slope.

On the other hand, when there is a recording section 7 on the surface of the paper as shown in FIG.
Since the scattered light caused by the recording part 7 is masked by the recording part 7 itself, the boundary between the printed part 7 and the non-printed part 6 appears sharp even when viewed with the naked eye. Looking at this in terms of the output of the detector 3, as shown in Figure B, the amount of reflected light at the boundary between the printed area 7 and the non-printed area 6 changes rapidly.
The rise and fall between sections 6' and 7' are steep.

According to the present invention, the amount of reflected light changes at the boundary between the printed area and the non-printed area when the printed area is on the back side of the paper and when it is on the front side, but has a gradient when the printed area is on the back side. By focusing on the fact that it is steeper when it is on the front side, by detecting and distinguishing this difference, it is possible to determine whether the printed area is on the back side or the front side.

There are two methods for determining whether the change in the detector output is steep or steep: a method that uses a high-pass filter, and a method that uses analog-digital (A/D).
D) There is a method that uses a converter. FIG. 6 is a block diagram showing an example of an automatic bankbook line setting device using a high-pass filter, and FIG. 7 is a diagram showing its operation timing. When passbook 1 is inserted, motor M is started with a motor drive command,
It is transported in the direction of the arrow by the feed rollers 8. A light emitting element 2 and a photodetector S are arranged toward the front surface A of the passbook. This photodetector S corresponds to the hyphen mark detector HMS shown in FIG. When the tip of the passbook 1 reaches the light receiving position, the light is received by the photodetector S, and the detection signal is input to the amplifier 9. The output of the amplifier 9 is input to the high pass filter 10, where it is determined whether the detector output waveform is steep or has a slope as described above. In other words, when the output of the amplifier 9 changes with a gradient as shown in Fig. 8A, the output of the high-pass filter 10 does not appear, and if the amplifier output changes steeply as shown in Fig. 9B, then the output of the high-pass filter 10 does not appear. Differential waveforms 11 and 12 are output on the negative side and then on the positive side. This output is input to the next comparator 13, the other input terminal of which is connected to the reference power source E, and the slice level -E is set. In this case, since the slice level is set to the negative side, the comparator 13 outputs a pulse as shown in FIG. 9C only when the first negative waveform 11 is input. The later + side waveform 12 and the high-pass filter output waveform 14 at the rise of the amplifier output in FIG.
is input, no comparator output pulse appears. The motor stop circuit 15 receives the output of the comparator 13 and the output of the timing mark detector TMS. In other words, when the passbook is sent by the motor, the timing mark detector TMS detects the detected waveforms of the timing marks T ₁₀ , T ₉ ...T ₃ , T ₂ in Fig. 1 as t ₁₀ , t ₉ ... t ₃ in Fig. 7.・Output as t ₂ . and,
When the first hyphen mark H ₂ reaches the light receiving position, the amplifier output waveform becomes steep as shown in Figure 9.
h ₂ ' appears, and the comparator output is input to the motor stop circuit 15 with the negative high-pass filter output waveform 11 as described above. Before that, the output waveforms h ₅ ′ and hyphen marks H ₅ and H ₆ on the back side.
h ₆ ' appears, but as explained in Fig. 8, the output changes are accompanied by a slope and do not appear as the output signal of the high-pass filter, so
It is processed as a hyphen mark on the back side, and even if the detected signal level is the same as or higher than that of the front hyphen mark, it will not appear on the comparator side.
As described in FIG. 3, when the hyphen mark signal _h2 is input to the motor stop circuit 15 and the next timing mark signal _t2 is input, the next line to be printed has arrived. The motor stop circuit 15 gives a delay time corresponding to the movement time of "1-1.5 lines", and when the line to be printed reaches the printing position shown in FIG. 6, a motor stop command is sent to the motor drive circuit 16. The motor M is output and the automatic row setting is completed.

FIG. 10 shows an embodiment in which a change in a detector output is detected using an A/D converter to automatically set a bankbook line. The process up to the point where the output signal of the photodetector 5 is amplified by the amplifier 9 is the same as in FIG. 6, so the explanation will be omitted. The output of the amplifier 9 is input to the A/D converter 17, where the amplifier output value is sampled every minute time, and the amplifier output value is converted into a digital quantity every minute time. In the A/D converter 17, for example, as shown in FIG. 11, the output terminal of the amplifier 9 is connected to one input terminal of each of nine comparators 181 to 189, and the other input terminal is connected to a resistor R. ... are connected, and the level set by the resistor R... is compared with the input value from the amplifier. At the same time, each comparator 181 to 189 is supplied with a clock signal from the control circuit 19.
As shown in FIG. 12, each minute clock is A/D converted and output. For example, if you set the maximum value of the amplifier output as 10 and the output value zero as 0, and convert it to a digital amount in 10 steps, the digital amount for each sampling time will change depending on the magnitude of the amplifier output.
Obtained as converter output. Each numerical value shown as an A/D converter output in FIG. 12 indicates a digital quantity obtained in this way. This digital output then passes through the memory 20 to the digital comparator 2.
1, and the other input terminal is directly input from the A/D converter 17.
In the memory 20, the digital converter output is shifted by one clock, for example (n-1), and outputted in a delayed form. Therefore, the digital comparator 2
1, adjacent digital quantities of the A/D converter outputs are compared and subtracted to obtain the value "(n-1)-n", and the numerical values illustrated in FIG. 12 appear. In other words, this shows that the steeper the change in the amplifier output value, the steeper the change in the digital amount between adjacent clocks. On the other hand, a slice level is externally set in the digital comparator 21, and only when the amount of digital change between adjacent clocks is greater than the slice level, an output pulse appears as ^h21 '.
It is input to the motor stop circuit 15. That is, in the illustrated example, since the slice level is set to 5,
Only when the digital amount change between adjacent clocks is 5 or more, that is, when the h ₂ ′ part where the amplifier output changes sharply appears, the signal is output to the motor stop circuit, and the h ₅ ′・
Locations where the amplifier output change has a slope, such as h ₆ ′, will be ignored. Amplifier output waveform
h ₅ ′ and h ₆ ′ are the signals corresponding to the hyphen marks H ₅ and H ₆ on the back side in FIGS. 1 and 2, and h ₂ ′ is the output signal from the hyphen mark H ₂ on the front side. Therefore, even by using an A/D converter, it is possible to determine changes in the amplifier output waveform and detect whether the hyphen mark is on the front side or the back side.

In the embodiment, a case has been described in which reflected light is detected, but if the medium is a light-transmissive medium such as white paper, the transmitted light of the medium 1 may be detected as shown in FIG. 13A. When the recording section is on the front side as shown in 7, the change in the transmitted light intensity is steep as shown in Figure B, whereas when it is on the back side as shown in 3, the change in the transmitted light intensity is accompanied by a gradient. It is also possible to distinguish between front and back sides by detecting transmitted light. In addition, although the case where a bankbook is used as a recording medium and automatic setting is performed on the printing part is described as an example, the present invention can be used in OCR (optical character reader), OMR (optical mark reader), etc. It can also be used to distinguish and read only characters and marks.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the recording surface of the passbook used for automatic line setting, Figure 2 is a diagram of the same bankbook viewed from the side,
Figure 3 is a time chart showing the timing mark and hyphen mark detection signals, Figures 4 and 5 are diagrams showing that it is possible to distinguish between the front and back sides of the printed area based on the intensity distribution of reflected light, and Figure 6 is a time chart showing the detection signals of timing marks and hyphen marks. The figure is a block diagram showing an embodiment in which a high-pass filter is used to distinguish between the front and back sides of the printing section, Figures 7 to 9 are time charts showing the operation of the same embodiment, and Figures 10 and 11 are A/ A block diagram of an embodiment in which a D converter is used to distinguish between the front and back sides of a printed area, FIG. 12 is an operation time chart, and FIG. 13 is a diagram showing that it is possible to distinguish between front and back sides of a printed area even with transmitted light. It is. In the figure, 1 is a recording material such as a bankbook, A is the front side, B is the back side, 2 is the light emitting element, 3 is the back side printing part,
4 is a fine light beam, 6 is non-printing, 7 is the front side printing part, H ₁ and H ₂ ... are hyphen marks, T ₁ and T ₂ ... are timing marks, S and HMS are hyphen mark detectors, TMS is timing marks It is a detector.

Claims (1)

[Claims] 1. A recording medium is irradiated with light from one side thereof, and is equipped with a photodetector that detects the reflected light or transmitted light, and when the recording medium and the photodetector are moved relative to each other, the irradiated light is connected to the recording section. A recording medium characterized in that it is determined whether the recording section is on the front side or the back side of the recording medium by determining the difference in the slope of the output change of the photodetector when passing through the boundary with the recording section. recording surface discrimination method.