JPS61262886A - Information reading device - Google Patents

Abstract

PURPOSE:To improve rate of reading of tags by giving functions of reading in normal direction and reading in reverse direction equivalently by configuration of a circuit. CONSTITUTION:The bar code counter 1 is a bar width counter that counts up by a fixed high speed clock, and counts from a changing point from black to white or from white to black to next changing point. The counted value corresponding to bar width is inputted to a memory 2 and a multiplexer 6. A multiplexer controlling signal (g) synchronized with scan of laser light is outputted from a scanning controlling circuit 8. Data written in the memory 2 in a time width A is read out from data written last by operation of an up counter 3, and in a time width B, data are read out from data written first by a down counter 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an information reading device for reading barcode labels in POS and the like.

[Conventional technology]

Figure 3 shows an information reading device that reads barcode labels.
FIG. 1 is a block diagram of a commonly used circuit.

In Figure 3, (1) is a bar width counter that counts the width of the bar made up of the focus inside the tag and white, and (7) is the barcode width counted in (1) and the bar code width that is continuously input. This is a processing circuit that checks the combination of bar rows, etc., and reads the contents of the barcode. (8) is a scanning control circuit that controls the timing of scanning the laser beam.

Figure 4 is an example of a tag (barcode label) read by an information reading device, (9) is the barcode label, (9)-h
.

+9)-1 and (9)-j indicate the scanning direction of the laser beam with respect to the barcode 4 and the movement of the beam. Also, FIG. 5 explains the contents of (9) barcode label.

Next, the operation will be explained with reference to FIGS. 3, 4, and 5.

When a laser beam controlled by the scanning control circuit (8) I shown in Fig. 3 scans the barcode (9) shown in Fig. 4 like a line (hereinafter referred to as h-scan). ) The input of the bar width counter shown in FIG. 3(a) is a pulse train corresponding to the black and white of the bar code. The bar width counter (1) is a counter that counts up at a certain high speed clock, and counts from one point of change from black to white or from white to black to the next point of change. That is -
If the width of the white or black bar is narrow, the count number will be small, and if the width is wide, the count number will be large.

A count value corresponding to this bar width is input to the processing circuit (7). The processing circuit (7) checks the combination of the bar width data and the continuously input signals, and reads the contents of the bar code. By the way, when the barcode (9) in Figure 4 is scanned by h, the entire area of the barcode label is scanned, so it can be read, but i-scan and j-scan only scan half of the barcode label. Therefore, the information in the barcode is only half of the information, and it cannot be considered as correct data. However, as shown in Figure 5, barcode labels are divided into data characters on the right side and data characters on the left side with the center bar in the middle, so in general, data from either the left or right side is scanned in one scan. If the label can be read, it is temporarily stored in the processing circuit (7) in Figure 3, and the data on the opposite side is read in the next scan. If the data is correct for both left and right sides, it is determined that the label has been read correctly, and the reading rate is determined. We are trying to improve the quality of our products.

However, as shown in Figure 5 (this barcode may have the same content as the center bar and left guard bar depending on the combination of data characters (for example, if the center bar has a white bar and a black bar is 1) ,0
It is represented by 1010, but the barcode of number 1 is 0011
If 001 and the number 4 barcode 0100011 are consecutive, it becomes 00110010100011, and the combination of 0 and 1 produces the same thing as center bar 01010)
One thing that happens is that you don't know where the barcode starts and ends.

Also, since barcodes are allowed to be enlarged and reduced (in other words, the absolute value of the bar width is not constant), the difference or width between a narrow barcode and a wide barcode can be determined by input. It is necessary to constantly go backwards to compare the bar widths before and after the previous data, and determine the current bar width.

Therefore, in order to read the barcodes shown in Figures 4 and 5, there is a left margin (a mountain width of 7 modules or more if the narrow width is 1 module) and a left guard bar as shown in Figure 5. - (101) indicates the end of the barcode (the only combination in the barcode)
After that, it is only necessary to judge whether the data of the data character, etc. is correct (the right side is similarly recognized by the combination of the right margin and the right guard bar). However, as mentioned above, in order to recognize the width of a barcode, it is necessary to climb backwards and compare while recognizing the current bar width, so this is the best way to find the left or right margin. The barcode in Figure 4 is (9) The special number that is scanned i can be read, but it cannot be read when scanned j. (A reverse scan is required to find the light margin.) Figure 4 shows 1 scan and j for explanation.
Although the forward direction of scanning and the direction of backward scanning are shown,
Optically, it is very difficult to perform such forward and reverse scanning, so a scanning method that only works in one direction is used.

[Problem that the invention seeks to solve]

Conventional information reading devices are configured as shown below, so if the barcode label is scanned in the direction shown in Figure 4 j scan, it cannot be read if the barcode label is in the position shown in the figure, and the information reading device ends up In order to increase the reading rate, it was necessary to increase the number of laser beams scanned per hour and to perform multidirectional scanning.

This invention was made in order to solve the above-mentioned problems, and it provides an optical tag (barcode label) with both forward and reverse reading functions equivalently in the reading direction. To obtain an information reading device with a high reading rate without performing complex scanning control.

[Means for solving problems]

The information reading device according to the present invention uses a memory that stores data for one scan of laser light and a circuit that reads the stored data in reverse order, so that the reading direction of the tag can be equivalently read in the forward direction. 0 [Operation] This invention has the function of both forward reading and backward reading by means of the circuit configuration, thereby enabling optical reverse reading. It is possible to improve the tag reading rate without performing optically complex scanning control such as directional scanning, increasing the number of scans per time, or multidirectional scanning.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, (1) is a bar width counter that counts the width of the black and white bars within the tag, and (2) is a bar width counter (a memory that temporarily stores the counted value from 10). , (3) is an up counter to give the address of the memo (January 2), (4) is a down counter to give the address of memory (2), and (5) is an up counter (3).
)2 and the output of the down counter (4), and (6) selects one of the outputs of the bar width counter (1) and the output of the memory (2). A multiplexer for selective output, (7) a processing circuit that checks the width of the counted barcode and the combination of consecutively input bar rows, etc., and deciphers the contents of the barcode, (8) a laser beam. This is a scanning control circuit that controls the timing of scanning.

FIG. 2 is a diagram for explaining details of the output g of the scanning control circuit (8) shown in FIG. 1.

The operation will be explained using FIG. 18, FIG. 2, FIG. 4, and FIG. 5.

When the laser beam controlled by the scanning control circuit (8) I in Fig. 1 is scanned as in the h-scan shown in Fig. 4, Fig. This results in a pulse train. Barcode counter (
1) is a bar width counter that counts up at a certain high speed clock, and counts from a point of change from black to white or from white to black to the next point of change. That is, if the width of the white or black bar is narrow, the count number will be small, and if the width is wide, the count number will be large. A count value corresponding to this bar width is input to the memory (2) and the multiplexer (6). Multiplexer control signal g synchronized with laser beam scanning from the scanning control circuit (8)
is output. Figure 2 shows the details of the signal g from the scanning control circuit (8), and the time period A is either the output of the up counter (3) or via the multiplexer (5), and becomes the memory address at the same time. Bar width counter (
The output of 1) is input to the processing circuit (7) via the multiplexer (6). That is, in the time period A, the count number corresponding to the bar width is input to the processing circuit (7) and written into the memory (2) from the lowest address to the highest address. The processing circuit (7) checks the value of b, that is, the width of the bar and the combination of continuously input signals to determine the content of the barcode. Since the entire area is scanned, reading is possible, but
In i-scan and j-scan, only half of the barcode is scanned, so the barcode information is only half, and cannot be correct data. However, as shown in Figure 5, a barcode label is divided into data characters on the right side and data characters on the left side with the center bar in the middle. If the label can be read, it is temporarily stored in the processing circuit (7) in Figure 1, and the data on the opposite side is read in the next scan.If the data is correct on both sides, it is determined that the label has been read correctly, and the We are working to improve the rate.

However, barcodes like the one shown in Figure 5.

Depending on the combination of data characters, the center bar and left guard bar may have the same content (for example, the center bar has a white bar of 02, a black bar of 1, and 0).
It is coded as 1010, but the barcode with number 1 is 0011.
If 001 and the number 4 barcode 0100011 are consecutive, it becomes 00110010100011, and the combination of 0 and 1 produces the same thing as the center bar 01.010), so it is impossible to tell where the barcode starts and ends. .

Also, since barcodes are allowed to be enlarged and reduced (in other words, the absolute value of the bar width is not constant), the difference or width between a narrow barcode and a wide barcode cannot be input. It is necessary to always go backwards and compare the bar widths, such as the data before and the data before that, to determine the current bar width.

Therefore, in order to read the barcodes shown in Figures 4 and 5, there is a left margin (a mountain width of 7 modules or more if the narrow width is 1 module) and a left guard barrier as shown in Figure 5. - (101) is recognized as the end of the barcode, and after that (the only combination in the barcode), it is only necessary to judge whether the data of the data character etc. is correct. (The right side is similarly recognized by the combination of one light margin and light guard bar). However, as mentioned above, in order to recognize the width of a barcode, it is necessary to go backwards and compare while recognizing the current bar width, so in order to find the left margin or right margin. It is possible to read when scanning in the direction of mis-scan in Figure 4, but it is impossible to read when scanning in the j-scan direction (reverse scanning is required to find the write margin). For explanation purposes, Figure 4 shows the forward and reverse scanning directions of i-scan and j-scan.It is very difficult to optically perform such forward and reverse scanning, so we recommend scanning in only one direction. We are hiring.

By the way, during the time period shown in FIG. 2B, the output of the down counter (4) becomes the address of the memory (2) via the multiplexer (5), and the address progresses from the higher address to the lower address.

In other words, the data written during the time period A will be the car number read from the last written data.

In other words, in the time period A, forward direction data (or reverse direction) is input to the processing circuit (7), and in the time period B, the forward direction data (or reverse direction) is inputted to the processing circuit (7).
data equivalent to the beam being scanned in both the i-scan and j-scan directions shown in FIG. 4 is input to the processing circuit (7). 7) is to check the bar width and signal combination of forward direction data in the time period A and reverse direction data in the time period B, and to read the contents of the barcode.

〔Effect of the invention〕

As described above, according to the present invention, a memory for storing data for one scan of laser light and a circuit for reading out the stored data in reverse order are provided.

Since it is possible to obtain a signal equivalent to optical scanning in both forward and reverse directions, there is no need to have a complicated optical system, and the device can be made at low cost and has a high reading rate. It has the effect of

[Brief explanation of the drawing]

1 is a block diagram of an information reading device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of internal signals in FIG. 1, FIG. 3 is a block diagram of a conventional information reading device, and FIG. 4 is a block diagram of an information reading device according to an embodiment of the present invention. FIG. 5 is a diagram illustrating an example of a tag (barcode label) read by a reading device and its scanning direction. FIG. 5 is a diagram illustrating the contents of the tag shown in FIG. 4. In the figure, (1) is a bar width counter, (2) is a memory, (3) is an up counter, (4) is a down counter,
(5) is a multiplexer, (6) is a multiplexer, (
7) is a processing circuit, (8) is a scanning control circuit, (9
) is a barcode label. In addition, the same reference numerals in the figures are the same, and 0 indicates the same note.

Claims (1)

[Claims] In a device that optically reads tag information using a laser scanner, the reading direction for the tag can be equivalently changed by using a memory that stores data for one scan of laser light and a circuit that reads the stored data in reverse order. An information reading device characterized in that it has both forward reading and backward reading functions to improve the tag reading rate.