JPH06111046A - Bar code reader - Google Patents

Abstract

PURPOSE:To always perform scan at the optimum reading area even without consciously performing an operation by an operator and to improve a reading ratio by providing a refractor, a recognition circuit, and a means to move a readable area. CONSTITUTION:A receiver 9 converts a laser beam 5 to an electrical signal 12, and a timing pulse generator 10 generates a timing pulse synchronized with a motor 4. A signal 14 is generated by a time difference waveform generator 13 based on the signals 12, 11. and the pulse width of the signal 14 is counted by a time counter 15. The angle of a polygonal mirror 2 rotated by the motor 4 is found by a time obtained from the pulse width of the signal 14, and it is detected at which position of an operating pattern a bar code 7 is read. When the bar code 7 passes the peripheral part of the operating pattern based on a detection result, a motor 20 for scanner movement is controlled by a scanner moving signal 19, then, a scanner can be moved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bar code reader.

[0002]

2. Description of the Related Art A conventional bar code reader is shown in FIG.
To read the barcode as shown in
In the area irradiated with the laser beam 24, the bar code 7 is passed through the reading area 25 having the reading area 5 in which the bar code can be actually read. Further, since the reading area 25 does not have a uniform reading rate in all areas, the reading rate is lowered particularly at the edges of the reading area.

[0003]

In this conventional bar code reading apparatus, an area in which the reading rate is low in the reading area, and the area where the reading rate is low or high even if the operator reads the barcode. It was difficult to judge. In addition, it is difficult for the operator to make a decision, so that it takes time for the operator to learn the operation.

[0004]

A bar code reader according to the present invention comprises a light source for emitting a laser beam, a refractor for scanning the laser beam, a bar code for irradiating the laser beam and receiving the reflected light. And a recognition circuit for recognizing the information of the bar code as numerical information based on the output of this light receiver, and a scanning timing signal of the laser beam in the refractor for outputting to the recognition circuit. It is provided with means for detecting where in the readable area the bar code read based on the timing signal is read, and moving the readable area so that reading is always performed in the optimum reading area.

[0005]

The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. The laser light 5 emitted from the light source 3 of the laser light is scanned by the polygon mirror 2 rotated by the motor 4, and the barcode 7 attached to the product is irradiated by the reflective glass 6. The laser beam 5 applied to the bar code 7 is scanned by a scanning pattern 2 as shown in FIG.
It is 1. The scanning pattern 21 has a high reading rate in the central portion, but has a low reading rate in the peripheral portion.

The difference between the reading rates is detected by the bar code recognition circuit 16 in FIG. 1, and the scanner moving signal 19 is used to control the scanner moving motor 20 to move the scanner so that the readable area of the scanner is changed by the operator. Move it to the optimum position.

Next, details of the bar code recognition circuit 16 for detecting the difference in reading rate are shown in FIGS. 3 (a) and 3 (b). The light receiver 9 converts the laser light 5 into an electric signal 12, and the timing pulse generator 10 generates a timing pulse 11 synchronized with the motor 4. Based on these two signals 12 and 11, a time difference waveform generator 13 outputs a signal 14
make. The pulse width t of this signal 14 is counted by the time counter 15. The bar code 9 shown in FIG. 2 is obtained by obtaining the angle of the polygon mirror 2 rotated by the motor 4 according to the time obtained by the pulse width t of the signal 14.
At which position in the operation pattern 21 the reading is performed is detected.

When the barcode 9 passes through the peripheral portion of the operation pattern 21 based on the detection result, the operation pattern 21
The scanner moving signal 20 controls the scanner moving motor 20 to move the scanner so as to pass through the center of the scanner. Further, the reading area also moves with the movement of the scanner, and the optimum reading area can be moved to a position suitable for the reading by the operator.

[0010]

As described above, according to the present invention,
Even if the operator is not aware of the optimum reading area of each scanner, the scanner can always scan in the optimum reading area, and the reading rate is improved.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a laser beam scanning pattern according to an embodiment of the present invention.

3 (a) and 3 (b) are a block diagram and a timing chart showing details of an embodiment of the present invention.

FIG. 4 is a schematic diagram showing a conventional example,

[Explanation of symbols]

 1 refractor 2 polygon mirror 3 laser light source 4 motor 7 bar code 9 light receiver 10 timing pulse generator 13 time difference waveform generator 15 hour counter

Claims (1)

[Claims] 1. A light source that emits laser light, a refractor for light that scans the laser light, a light receiver that irradiates the laser light on a bar code, receives the reflected light, and converts the reflected light into an electric signal, and this light receiver. A recognition circuit that recognizes the information of the bar code as numerical information based on the output of, and a bar code read area based on the timing signal that is output to the recognition circuit of the scanning timing signal of the laser light in the refractor and is a readable area And a means for moving the readable area so that the reading is always performed in the optimum reading area.