JPH074675Y2 - Optical character reader - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an optical character reading device, and more particularly to an optical character reading device having a mechanism for removing paper dust adhering to a light source.

[Conventional technology]

Conventionally, this type of optical character reading device conveys a form to be read on a conveyance path, irradiates the form with a light source provided above the conveyance path, and converts the reflected light into an electric signal by a photoelectric converter. , An image such as a character on the form was detected.

[Problems to be solved by the device]

In the conventional optical character reading device described above, paper dust or other dust generated when the form is conveyed adheres to the surface of the light source, the light from the light source is blocked, and the amount of light irradiated on the form decreases. As a result, the S / N ratio of the video signal that is the output signal of the photoelectric converter deteriorates, and when performing the character recognition operation based on the character image obtained from the video signal,
There is a problem that the character recognition performance is reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical character reading device capable of preventing a decrease in light amount of the optical character reading device and performing a character recognition operation stably without being affected by dust.

[Means for Solving the Problems]

The optical character reader of the present invention comprises a paper dust removing means for removing the paper dust attached to the tube surface of the light source, a driving means for moving the paper dust removing means along the light source, and the paper dust removing means for removing the paper dust. Relative position detecting means for detecting the relative position to the light source, the movement direction of the paper dust removing means is determined by the output of the relative position detecting means, the driving means is operated, and the paper dust removing means is moved along the light source. And a control means for controlling the drive means so as to move.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

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

When the power-on reset signal 8 is input to the motor control circuit 5, the micro switch 3 (relative position detecting means)
Output signal 6 and output signal 7 of the micro switch 4 (relative position detecting means) determine the moving direction of the paper dust removing device 1 and rotate the motor of the motor unit 2 (driving means) to remove the paper dust removing device. 1 is moved along the light source 10 to remove the paper dust.

FIG. 2 is an explanatory diagram showing a state in which the paper dust removal of the optical character reading device of FIG. 1 is performed. The motor unit 2 including the ball screw 9, the paper dust remover 1, the microswitches 3 and 4, and the light source 10 are shown.
Is shown.

The ball screw 9 is rotated by the motor of the motor unit 2, the paper dust removing device 1 driven by the ball screw 9 moves along the light source 10, and hits one of the microswitches 3 and 4 attached to both ends of the light source 10. Stop moving.

3 is a circuit diagram showing a motor control circuit of the optical character reader of FIG. 1, and FIG. 4 is a waveform diagram showing signal waveforms of respective parts of the motor control circuit of the optical character reader of FIG. .

In FIGS. 3 and 4, 24 is a timing when the motor rotation direction control switches 19 to 22 are turned on, 25 is a timing when the motor rotation switch 23 is turned off, 26 is a power-on timing, and 27 is a power-off timing. The timing, 28 is the rising timing of the power-on reset signal, 29 is the timing when the motor rotation switch 23 is turned on, 30 is the timing when the paper dust removing device 1 is separated from the micro switch 3, and
Reference numeral 31 indicates a timing at which the paper dust removing device 1 turns on the micro switch 4. In addition, the period during which the paper dust removing device 1 moves from the micro switch 3 to the micro switch 4 is the period T ₁
The period during which the paper dust removing device 1 moves from the micro switch 4 to the micro switch 3 is referred to as period T ₂ .

In period T ₁ , before turning on the optical character reader,
The paper dust removing device 1 is located on the side of the micro switch 3, the micro switch 3 is on, and the output signal 6 of the micro switch 3 is at the “High” level. The state of the microswitch 4 indicated by the output signal 7 of the microswitch 4 at the rising signal of the power-on reset signal 8 (timing 28 of period T ₁ in FIG. 4) when the power of the optical character reading device is turned on is controlled by the motor rotation direction. Is input to the flip-flop 15 for output, the direction of rotation of the motor of the motor unit 2 is determined, the paper dust removing device movement direction signals 16 and 17 are output, and the motor rotation direction control switches 19 to 22 are opened and closed (Fig. 4). Timing of period T ₁ 24).

At the same time, the AND circuit 11 to which the output signal 6 of the microswitch 3 and the power-on reset signal 8 are input and the output signal 7 of the microswitch 4 and the power-on reset signal 8 to the AND circuit 12 are input. The two signals output from the OR circuit 13 are input to the OR circuit 13, and the signal output from the OR circuit 13 is input to the motor control flip-flop 14. When the power is turned on (the paper dust removing device 1 is stagnated at the timing 26 of the period T ₁ in FIG. 4 and is turned on by the micro switch 3 the signal of the clock input terminal of the motor control flip-flop 14 rises. 18 is output and the motor rotation switch 23 is turned on (the period in FIG. 4 is
Timing 29 of T ₁ ) The paper dust removing device 1 is moved over the entire light source (timing 24 of period T ₁ in FIG. 4).

When the paper dust removing device 1 starts to move, the micro switch 3 is turned off, and the output signal 6 of the micro switch 3 becomes "Low" level (timing 3 of period T ₁ in FIG. 4).
0). When the paper dust removing device 1 moves over the entire light source and finishes removing the paper dust adhering to the light source 10, the micro switch 4 on the side opposite to the one when the power is turned on is turned on (timing of period T ₁ in FIG. 4). 31), at the same time, motor control flip-flop
The signal at the clock input terminal 14 rises, the output motor control signal 18 turns off the motor rotation switch 23, and the movement of the paper dust removing apparatus 1 is completed (timing 25 of period T ₁ in FIG. 4).

As described above, the paper dust of the light source can be removed after the power source of the apparatus is turned on (timing 26 of period T ₁ in FIG. 4).

The same operation is performed when the power is turned off (timing 27 of period T ₁ in FIG. 4) and the power is turned on again (period T ₂ in FIG. 4).

[Effect of device]

As described above, the present invention detects the paper dust removing means for removing the paper dust of the light source, the driving means for moving the paper dust removing means back and forth along the light source, and the relative position of the paper dust removing means with respect to the light source. By providing the control means for controlling the relative position detecting means and the driving means and removing the paper dust adhering to the light source of the optical character reading device, it is possible to prevent the decrease in the light amount of the optical character reading device and to recognize the character. This has the effect that the operation can be performed stably without being affected by dust.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an embodiment of the present invention, and FIG.
FIG. 3 is an explanatory view showing a state of removing paper dust of the optical character reading device shown in FIG. 3, FIG. 3 is a circuit diagram showing a motor control circuit of the optical character reading device shown in FIG. 1, and FIG. 4 is an optical character reading shown in FIG. It is a wave form diagram which shows the signal wave form of each part of the motor control circuit of a device. 1 ... paper dust removing device, 2 ... motor section, 3,4 ... micro switch, 5 ... motor control circuit, 6 ... micro switch 3 output signal, 7 ... micro switch 4 output signal, 8 ...... Power-on reset signal, 9 …… Ball screw, 10 …… Light source, 11,12 …… AND circuit, 13 …… OR circuit, 14
...... Motor control flip-flops, 15 …… Motor rotation direction control flip-flops, 16,17 …… Paper dust removing device movement direction signal, 18 …… Motor control signal, 19 to 22 …… Motor rotation direction control switch , 23 …… Motor rotation switch.

Claims (1)

[Scope of utility model registration request] 1. A paper dust removing means for removing paper dust attached to a tube surface of a light source, a driving means for moving the paper dust removing means along the light source, and a relative position of the paper dust removing means with respect to the light source. To determine the moving direction of the paper dust removing means by the output of the relative position detecting means and the relative position detecting means to operate the driving means to move the paper dust removing means along the light source. An optical character reading device comprising: a control unit that controls the drive unit.