JPS60140481A - Barcode reader - Google Patents

Abstract

PURPOSE:To improve reading performance for plural beams by making a beam decision circuit so that it will control a switching circuit in accordance with the decided beam during scanning. CONSTITUTION:A sensor 12 senses beams whose intensity corresponds to black of the bar code on a label, white of the base, etc., and converts them to electrical signals. In other words, photoelectric conversion is executed. A rotation signal detection circuit 7 detects the rotational angle of a motor 11, and a beam decision circuit 8 decides the type of the beam during scanning in a fixed scanner device 1 based on the rotational angle which is detected here. In addition, the beam decision circuit 8 controls changeover switches SW1 and SW2 and connects a differential circuit A 3 to a reading circuit under the condition that the beam during scanning in the fixed scanner device 1 is decided to be a beam (a). Then, the beam decision circuit 8 controls the changeover switches SW1 and SW2, and connects a differential circuit B 4 to the reading circuit under the condition that the beam during scanning in the fixed scanner device 1 is decided to be a beam (b).

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention has a fixed scanner device that scans a label using a plurality of beams in different directions, and can read barcodes in various directions. The present invention relates to a bar code reading device in which a differentiating circuit is switched according to the frequency of a scanning beam to eliminate deterioration in reading performance due to differences in scanning beams.

[Conventional technology and problems]

FIG. 1 is a diagram for explaining a fixed scanner device, and FIG. 2 is a diagram for explaining reading characteristics.

In FIG. 1, S is a fixed scanner device, A and B are scanning planes, and a and b are beams. The fixed scanner device S generates a plurality of beams of different types, such as beams a and b having scanning surfaces A and B, so that the barcode on the label can be read no matter which direction the label is tilted. It has become. However, in such a fixed scanner device S, the scanning speed differs depending on the f14M of the beam. Therefore, the output signal obtained by scanning using this fixed scanner device S has a wide frequency band. Normally, barcode reading circuits use a differential circuit to detect signal changes at the boundary between the black of the barcode and the white of the label, so they have circuit characteristics (differential characteristics) as shown in Figure 2. are doing.

For example, if the signals obtained by scanning scanning planes A and B with beams a and b shown in FIG. 1 are in the frequency bands shown in FIG. The output amplitude of the signal in the case of scanning plane A') 8''i is considerably smaller than the output amplitude of the signal in the case of scanning plane B by beam b.

Therefore, the reading performance of the reading circuit for scanning surface B by beam b becomes extremely poor. Therefore, if the frequency band of the reading circuit is widened in order to ensure that there is no difference in reading performance between scanning plane A by beam a and scanning plane B by beam b, the overall reading performance will deteriorate. There are five problems.

[Purpose of the invention]

The present invention is based on the above consideration, and an object of the present invention is to provide a barcode reading device with improved reading performance for a plurality of beams.

[Structure of the invention]

To this end, the barcode reading device of the present invention has a fixed scanner device that scans the label using a plurality of beams with different scanning directions, and differentiates the output signal obtained by detecting the beams that scan the label and scans the label. A barcode reading device for reading barcodes includes a plurality of differentiating circuits having characteristics corresponding to the frequency bands scanned by the plurality of beams, a beam determination circuit for determining the beam being scanned, and a plurality of differentiating circuits for reading the plurality of differentiating circuits. a switching circuit for switching connection to the circuit; the beam determining circuit controls the switching circuit according to the determined beam being scanned; and a reading circuit reads a differentiating circuit having characteristics corresponding to the frequency band scanned by the beam It is characterized by being configured to be connected to.

[Embodiments of the invention]

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

FIG. 3 is a diagram illustrating the frequency characteristics of a barcode reading device to which the present invention is applied, and FIG. 4 is a diagram showing the configuration of one embodiment of the present invention. In FIG. 4, 1 is a fixed scanner device b12 and 5 are amplifiers, 3 and 4 are differentiating circuits, 6 is a demodulation circuit, 7 is a rotation signal detection circuit, 8 is a beam determination circuit, 11 is a motor, 12 is a sensor, SWl and SW2 indicate a changeover switch.

As shown in FIG.
A circuit having a circuit characteristic (differential characteristic) of CA% CB is prepared according to the frequency band of , and the circuit is switched according to the type 4 of the traveling beam.

FIG. 4 shows a 14th embodiment of the present invention. In FIG. 4, the identification scanner sand 1 is the same as the fixed scanner device S shown in FIG.

Beams a and b are switched according to the rotation angle of the motor 11. Then, the beam that scans the label is sensed by the sensor 12. The sensor 12 senses a beam whose intensity corresponds to the blackness of the barcode on the label, the whiteness of the background, etc., and converts it into an electrical signal. Performs photoelectric conversion on request. The rotation signal detection circuit 7 is.

The rotation angle of the motor 11 is detected, and the beam determination circuit 8 determines the type of beam being scanned by the fixed scanner device based on the rotation angle detected here. Further, on the condition that the beam being scanned by the fixed scanner device 1 is determined to be the beam a, the beam determination circuit 8 switches the changeover switches SWI and SW2 to 'K'1.
lill n1ll, connect the differentiating circuit 3 to the reading circuit, and set the condition (/C1 changeover switch S
The differential circuit 4 is connected to the reading circuit by controlling WI and SW2. The amplifier 2 amplifies the output signal of the sensor 12, and the amplifier 5 amplifies the output signal of the differentiating circuit 3 or 4. The signal amplified by the amplifier 5 is demodulated by the demodulation circuit.

〔Effect of the invention〕

As is clear from the above explanation, according to the VC1 invention, the beam being scanned is set to +4'' and a circuit with characteristics corresponding to the beam is switched and connected using a switch, so each beam has a different frequency band. Almost the same reading performance can be obtained even if the reading performance is the same, and the reading performance as a whole can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining a fixed skid device, FIG. 2 is a diagram explaining reading characteristics, FIG. 3 is a diagram explaining frequency characteristics of a barcode reading device to which the present invention is applied, and FIG. FIG. 1 is a diagram showing the configuration of an embodiment of the present invention. 1 and S...Shield 1 fixed scanner equipped, 2 and 5...Amplifier,
3 and 4...component circuit, 6...demodulation circuit, 7...rotation signal detection circuit, 8...beam determination circuit, 11...
Motor, 12...sensor, A and B...scanning plane, a and b...beam, SWI and SW2...changeover switch. Patent Applicant: Fujitsu Ltd. Representative Patent Attorney: Kyotani Yobu Y 1 Zufuki Z Drawing: Dai Namimaki

Claims (1)

[Claims] In a barcode reading device that has a fixed scanner device that scans a label using a plurality of beams with different scanning directions, and that reads a barcode on a label by differentiating an output signal obtained by detecting the beam that scans the label, a plurality of differentiating circuits having characteristics corresponding to the frequency bands scanned by the plurality of beams; a beam determination circuit for determining the beam being scanned;
A switching circuit is provided that switches and connects the plurality of differentiating circuits to a reading circuit, and the beam determining circuit controls the switching circuit according to the determined beam being scanned to correspond to the frequency band scanned by the beam. A barcode reading device characterized in that a characteristic differentiating circuit is connected to a reading circuit.