JPH04216184A - Bar code reader - Google Patents

Abstract

PURPOSE:To obtain a margin detecting signal which is the optimum for decoding in corresponding to the kind of bar code labels. CONSTITUTION:This bar code reader obtains bar code signals 101 by scanning a bar code label by means of a scanning section 1 and digitizing electric signals converted by a light receiving section 2 by means of an AD-converting section 3. The bar code signals 101 have margin areas at their leading and trailing sections and a decoding section 5 decodes the bar code signals 101 by discriminating the margin areas, but, since the margin areas change depending upon the kind of the bar code label, a digital signal analyzing section 4 outputs a margin area detecting signal 103 by changing the pulse width of the signal 103 in corresponding to the kind of the bar code label by manually inputting the pulse width from the decoding section 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code reading device, and more particularly to a bar code reading device that is flexible in detecting a margin area as a bar blank area provided before and after a bar code.

0002

2. Description of the Related Art Barcode reading devices for reading barcodes contained in barcode labels printed or attached to products are well known.

[0003] There is a margin area as a blank area before and after the barcode on the barcode label. A barcode reading device decodes a barcode based on signals related to the widths of the black bars and the white space between the black bars provided by the barcode, and signals for confirming the margins before and after the barcode. In other words, the barcode is read by checking the margins and confirming the authenticity of the barcode to be read.

FIG. 2 is a block diagram of a conventional barcode reading device.

A conventional barcode reading device includes a scanning section 1 that optically scans a barcode label using a laser beam or the like, and a light receiving section 2 that receives reflected light from the scanning section 1 and converts it into an electrical signal. and an A/D converter 3 which A/D converts the output of the light receiving unit 2, digitizes it, and outputs it as a barcode signal 101, and analyzes the barcode signal 101 and converts the white margin area and the black bar of the barcode. A digital signal analysis unit 9 outputs pulse width data 102 corresponding to the white background between black bars, a margin detection signal 103 that exists before and after the barcode and proves that the area between them is a barcode area, and pulse width data 102 and margin detection. A decoding section 10 that decodes the contents of the barcode based on the signal 103 is provided.

[0006] After passing through the scanning section 1 and the light receiving section 2, the A/D conversion section 3
The digitized barcode signal 101 has a high level signal due to the reflected light from the margin area before and after the barcode, a low level signal due to the black bars of the barcode, and a high level signal due to the reflected light from the white area between the black bars of the barcode. This is time-series pulse data including a level signal.

The barcode signal 101 is sent to the digital signal analysis section 9 and supplied to the pulse width counter 6 and the margin detection signal generator 11.

The pulse width counter 6 receives the barcode signal 1
In addition to high-level pulses due to the margins before and after the barcode included in 01 and high-level pulses due to the white part of the barcode, pulses corresponding to the black bar part are formed,
The pulse width including all these pulses is counted and output as pulse width data 102.

On the other hand, the margin detection signal generator 10 performs margin detection to confirm the existence of a margin area occupying the front and rear of the bar code signal 101.

Margin detection is performed by focusing on the pulse width of the high-level pulse included in the barcode 101. That is, the barcode itself consists of a black bar having a specified width and a white area corresponding to the black bar. On the other hand, the margin area before and after the barcode itself is
In both cases, the pulse width is set to be sufficiently longer than the two widths of the black and white parts. Therefore, after detecting the presence of two margin areas on the front and back under the judgment condition that it is equal to or smaller than the width of the margin and larger than the thick black bar of the barcode, the one-shot multivibrator is activated at the timing of this detection. A margin detection signal 103 with a specific pulse width is output using a circuit or the like. This specific pulse width is also set based on the determination conditions described above.

The decoder 10 confirms the authenticity of the barcode signal using the margin detection signal 103, and decodes and displays the contents of the barcode based on the pulse width data 102.

0012

[Problems to be Solved by the Invention] The conventional barcode reading device described above sets the pulse width of the margin detection signal as variable in accordance with the bar thickness and margin, which vary depending on the type of barcode label to be read. It is necessary to confirm the accurate margin by setting the margin, and this setting requires the experience and intuition of a veteran adjuster, which poses the problem of a lack of flexibility in setting.

[0013] The purpose of the present invention is to solve the above-mentioned problems,
It is an object of the present invention to provide a barcode reading device that greatly facilitates the setting of the pulse width of a margin detection signal.

[0014]

[Means for Solving the Problems] The barcode reading device of the present invention reads the margin areas on both sides of the barcode printed on the barcode label and outputs the length of the margin detection signal, which can be arbitrarily controlled from the outside. It is configured with a means for configuring the settings.

Further, the barcode reading device of the present invention uses any one of a plurality of clock cycles with a preset number of repetitions corresponding to the type of barcode label and the average scanning speed.
the margin area reading time is input, and the presence of the margin area included in the barcode signal obtained by reading the barcode label is confirmed based on the count number counted by inputting the margin area reading time, and a margin detection signal is output. .

Furthermore, the barcode reading device of the present invention has the following features:
It has a configuration in which designation of the plurality of repetition numbers of clocks can be externally set by manual input, and the length of the margin signal is set.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. The configuration of the embodiment shown in FIG. 1 is the same as the conventional example shown in FIG. Be prepared.

Next, the operation of this embodiment will be explained.

The barcode label scanned by the scanning unit 1 is converted into an electrical signal by the light receiving unit 2, and information regarding the reflected light and the black bar in the barcode area of the margin area is A as a high-level and low-level barcode signal 101, respectively. The signal is digitally converted by the /D converter 3 and supplied to the digital signal analyzer 4.

When the digital signal analyzer 4 receives the barcode signal 101, it supplies it to the pulse width counter 6 and the margin detection signal generator 8.

As in the conventional example shown in FIG.
is formed and sent to the decoding section 5.

The programmable timer 7 has a standard clock generator and a frequency divider circuit that divides and outputs the clock output from the standard clock generator using a plurality of frequency division ratios. A clock with a frequency division ratio specified by the frequency ratio setting signal 104 is output and supplied to the margin detection signal generation circuit 8.

The decoder 5 manually inputs a frequency division ratio setting signal 104 that specifies the pulse width of a plurality of margin detection signals, which is preset based on the type of barcode label and the type of barcode reading device. The programmable timer, which has a function of outputting the frequency division ratio setting signal 104, sends a clock having the designated frequency division ratio to the margin detection signal generator 8.

The margin detection signal generator 8 is configured as a kind of preset counter, and the clock terminal CK is supplied with a clock 105 output from the programmable timer 7, the clear terminal CLR is supplied with a bar code signal 101,
A margin detection signal 103 is output from the output terminal Q.

The margin detection signal generator 8 presets a certain number of count values and outputs the input clock 1.
05, the preset value is counted down and when it reaches zero, a margin detection signal 103 is output. The preset value is set in advance in accordance with the type of barcode and the average scanning time of the margin area. Therefore, by changing the number of repetitions of the clock 105 using the programmable timer 7, the countdown can be reached from the count start to the countdown. In this embodiment, by changing the clock 105 output from the programmable timer 7 as a plurality of repetitions based on a plurality of frequency division ratios, the evaluation time for margin area reading can be arbitrarily set. Compatible with barcode labels.

Now, when the margin detection signal generator 8 receives a number of clocks 105 equal to the preset value,
As a result, when the preset value is counted down to zero and the count is completed, the margin detection signal 103 is output and sent to the decoder 5, and the barcode signal is sent to the clear terminal CLR before the input clock 105 reaches the preset value. When input, it is reset and the margin detection signal 105 is not output. In this way clear terminal CL
A margin detection signal 103 is output only when a margin area scanning signal is input to R, and the generation period of this margin signal, that is, the pulse width, is arbitrarily controlled by a frequency division ratio setting signal 104 set by the decoder 5. It is possible.

Based on the type of barcode and barcode reading device, the operator manually inputs the desired frequency division ratio setting signal 104 from the decoder 5 in advance to obtain a margin detection signal corresponding to the barcode label. 103 can be output.

[0029]

[Effects of the Invention] As explained above, the present invention provides an optimal solution for barcode labels by making it possible to vary the pulse length of the margin detection signal according to the type of barcode label by manual input to the decoder. This has the effect of making it possible to adjust the pulse length of the margin signal.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional barcode reading device.

[Explanation of symbols]

1 Scanning section 2 Light receiving part 3 A/D conversion section 4 Digital signal analysis section 5　　　　Decoding part 6 Pulse width counter 7 Programmable timer 8 Margin detection signal generator 9 Digital signal analysis section 10　　　Decoding part 11 Margin detection signal generator

Claims (3)

[Claims] Claim 1: The present invention is characterized by comprising means for externally arbitrarily setting the length of a margin detection signal that is output by reading margin areas on both sides of a barcode printed on a barcode label. Barcode reader. 2. Based on the count number obtained by inputting the margin area reading time of any one of a plurality of clocks with a preset number of repetitions corresponding to the type of barcode label and the average scanning speed, A barcode reading device comprising means for confirming the existence of the margin area included in a barcode signal obtained by reading a barcode label and outputting a margin detection signal. 3. The bar code reading device according to claim 1, wherein the length of the margin signal is set by allowing designation of the plurality of repetition numbers of clocks to be set externally by manual input.