JPS6334507B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a barcode reading device, and an object of the present invention is to simplify the configuration of the reader by printing the barcode with an electrically resistive material, thereby facilitating hand scanning. The aim is to provide a device with fewer misreadings.

Conventional optical barcode readers require a light source and a light receiving element, as well as a lens for focusing on the barcode, and are often expensive and have weak mechanical strength. In addition, these systems determine the width of the bar based on the time it takes for the reader to pass over the barcode, so it is difficult to reliably read the barcode because the operating speed varies and is uneven, especially in hand-scanning methods where a person operates the barcode by hand. It was difficult.

The present invention eliminates the above-mentioned conventional drawbacks, and the structure thereof will be explained below with reference to the drawings shown as embodiments.

In FIG. 1, 1 is a bar code, which is printed by converting arbitrary information into the thickness of the bar. This barcode 1 is printed using an electrically resistive material (for example, a carbon resistive material). 2 is a reader, which is a pen-type hand scanning type reader having a handgrip 3. 4 and 5 are insulated electrodes, 4' and 5' are lead wires drawn out from the electrodes 4 and 5, and 6 is a reading circuit, and the lead wires 4' and 5' are led from the electrodes to this reading circuit. ing. Note that the reading circuit 6 may be built into the reader 2. Here, the reader 2 slides the electrodes 4 and 5 in contact with the barcode 1, and measures the resistance value of the bar in contact between the electrodes 4 and 5. Since the distance l between the electrodes 4 and 5 is constant, the resistance value is determined by the thickness of the bar. Also, the resistance value between bars becomes infinite. FIG. 3 shows another embodiment of the bar code, in which bars 8 extend from a common line 7 in a comb shape. This solves the problem that when the bars are thin or the gap is small, it is difficult to contact one bar at the same time with the electrodes 4 and 5 having a distance l, and the electrode 5 slides on the common line 7. Then, the resistance value between this and the electrode 4 sliding on each bar 8 is measured.
FIG. 4 shows a specific circuit example of the reading circuit 6.
C is a detection circuit that detects the resistance value of the bar, and a bridge is constituted by resistors 9, 10, 11 and a resistor R formed by the bar that is in contact with electrodes 4 and 5, and the midpoint potentials e and f of the bridge are connected to the operational amplifier. It is connected to 12 positive and negative input terminals. Resistors 13 and 14 are resistors that determine the amplification gain of operational amplifier 12. The output b of the operational amplifier 12 is connected to the positive input terminal of each of comparators 15 and 16 of a first detection circuit section B that detects the presence or absence of a bar and a second detection circuit section A that detects the presence or absence of a thick bar. ing. Also, resistor 17,
The potentials g and h divided by 18 and 19 are applied to comparator 1.
5 and 16, respectively.
The comparators 15 and 16 are generally known two-input open collector output comparators, and the outputs d and c are switched between high and low depending on the potentials of the positive and negative input terminals. The outputs d and c are pulled up by resistors 17 and 18, respectively, so when the comparators 15 and 16 are high output, the potentials d and c are the potential of the power supply 19, and when the comparators 15 and 16 are low output, the potentials d and c are the potential of the power supply 19. becomes electric potential. The operation of reading the barcode shown in FIG. 5a by operating the reader 2 in the direction of the arrow will now be described.
Before the reader enters the barcode (state P in figure a)
Because there is no bar in
constitutes an inverting amplifier circuit, so its output b is almost zero. At this time, since the potential b<h<g, both the outputs d and c of the comparator become low, and it is known that there is no current signal. This is state R in Figure 5a,
The same applies to T, V, X, and Z.

Now, when reading data as shown in FIG. 5A with two types of barcode thickness, a thin code of 0 and a thick code of 1, in state Q, the resistance value is large because the bar is thin. At this time, as shown in figure b, the potential b
Since h<b<g, the output c is high and the output d is low. That is, the presence of data is known from the output signal c of the first detection circuit section, and the data can be recognized as 0 because the output signal d of the second detection circuit section is low at that time. This also applies to state W in figure a. Next, in state R, outputs c, d
After both become low, in state S, the bar is thick, so the resistance is small and the potential f becomes low, so the output b becomes h
<g<b, and the potential c goes high, so it knows that there is data, and the potential d goes high, so it knows that the data is 1. This also applies to U and Y in Figure a. By repeating the above steps, the presence or absence of data and whether the data is 0 or 1 is determined based on the states of outputs c and d. In other words, if the output c is low, there is no data. If the output c is high, there is data, and if the output d is low, it is determined to be 0, and if it is high, it is determined to be 1. The barcode can be a combination of sticks as shown in Figure 1, but if it is printed in a comb shape as shown in Figure 3, it can be read even if the reader is held diagonally. There is no difference in how you hold the leader.

As explained above, the barcode reading device of the present invention has the following effects.

(1) Data can be read accurately even if the operating speed of the reader is uneven because the width of the barcode is read by the electric resistance value instead of reading the data by the passing time on the barcode as in the past.
Therefore, it is effective in a hand scanning method in which the reader is manually operated by a human.

(2) a first detection circuit unit that detects the presence or absence of a bar;
Since it is configured to read with two signals from the second detection circuit that detects the presence or absence of a thick bar based on the resistance value of the bar, it is easy to distinguish between a place where there is no bar signal and a 0 signal of the binary digital signal, resulting in false detection. There is no.

(3) Since it is possible to provide a sufficient potential difference between potentials g and h, it is possible to accurately detect humidity, uneven printing of bars, and blurring.

(4) The reader has only two electrodes that contact the barcode, making it robust, lightweight, and inexpensive.

In the above description, the bar thickness was explained as being two types, but it is also possible to apply the present invention to bars of various thicknesses by simply modifying the configuration of the detection circuit.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing one embodiment of the barcode reading device of the present invention, Fig. 2 is an enlarged sectional view of the main part of the reader shown in Fig. 1, and Fig. 3 shows another embodiment of the barcode. Plan view, Figure 4 is the reading circuit diagram, Figure 5
This figure is a characteristic diagram showing the potential of each part in the circuit of FIG. 4. 1...Barcode printed with electrically resistive material,
2...Reader, 3...Hand grip section, 4, 5
...Electrode, 6...Reading circuit, 7...Bar code common line, 8...Bar, A...Second detection circuit section, B...First detection circuit section, C...Detection circuit .

Claims (1)

[Claims] 1. In order to read a bar code printed with an electrically resistive material with a combination of two bar thicknesses representing a binary digital value, a bar code is slid over the bar code in a direction perpendicular to the direction of the bar. A barcode reading device comprising a reader having two electrodes arranged in a direction and a reading circuit for reading the barcode detected by the reader, wherein the reader has a hand grip part that can be operated by hand. , the reading circuit includes a detection circuit that detects the electrical resistance between the two electrodes, a first detection circuit section that detects the presence or absence of a bar based on the output of the detection circuit, and a first detection circuit section that detects the presence or absence of a bar based on the output of the detection circuit. A barcode reading device comprising: a second detection circuit unit that detects the presence or absence of a bar, and reads a barcode based on the outputs of both detection circuits.