JPS63188085A - Method for detecting label of label printer - Google Patents

Abstract

PURPOSE:To prevent the erroneous operation of a circuit due to the effect of the temp. characteristic inherent to an optical sensor or disturbance, by converting the analogue output detected by the optical sensor to digital output subjected to time sharing and calculating the differential value of said data and detecting a part to be detected on the basis of the detected wave form of said differential value. CONSTITUTION:When an optical sensor 24 detects a part to be detected different in light transmissivity, the light receiving quantity of a light receiving element 23 changes and the voltage on the side of a collector 25 varies and output voltage Vout of the analogue wave form on the side of the collector 25 appears. The output voltage Vout of this analogue wave form is timewise divided at an equal interval >=t by an A/D converter 18 to be converted to digital wave form (S1...S15). Then, the digital value S1 is subtracted from the digital value S2 using RAM 19 and ROM 20 to calculate difference d1. Next, when the difference d1 is divided by the interval DELTAt subjected to time sharing, a differential value D1 is calculated. Hereinafter, in the same way, differential values (D2,...D14) are calculated. By calculating the differential values (D1..., D14) by this method, the change quantity and change direction (+/-) of the output voltage Vout can be investigated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a label detection method for a label printer that detects detection areas such as gaps and notches with different light transmittances on continuous paper.

2. Description of the Related Art A conventional gap detection circuit for detecting a gap between labels as detected parts will be explained with reference to FIGS. 5 to 10.

The conventional gap detection circuit 1 includes an optical sensor circuit section 6 that detects the gap 5 between the detected parts of the continuous paper 2 having different light transmittances, that is, the labels 4 affixed to the mount 3 in FIG. A comparator 7 for waveform shaping, a 10 port 8, and a CPU 9 are provided. The optical sensor circuit section 6 includes an optical sensor 12 including a light emitting element (LED) 10 and a light receiving element (phototransistor) 11.

The light emitting element 10 is connected to the power supply Vcc via a resistor R8, and the collector 13 side of the light receiving element 11 is connected to the power supply Vcc via a variable resistor VR. Further, the collector 13 side of the light receiving element 11 is connected to one input terminal of the comparator 7 located at the next stage, and the reference voltage Vo is connected to the other input terminal of the comparator 7. The output side of this comparator 7 is connected to the I10 port 8 located at the next stage, and this I10 port 8 is connected to the CPU 9 through a bus 14. Note that the notches 15 formed at equal intervals on one side edge of the mount 3 correspond to the detected portions in FIG.

In such a configuration, when the optical sensor 12 detects detected parts with different light transmittances, the amount of light received by the light receiving element 11 changes, the voltage on the collector 13 side fluctuates, and an analog waveform is applied to the collector 13 side. An output voltage Vout appears. When this output voltage Vout is regarded as a detection voltage and compared with the detection levels a and b of the comparator 7, a waveform-shaped pulse-shaped detection waveform is obtained. At this time, the detection level is divided into two, a and b, but this is because detection is performed based on the threshold level, and the downward curve is detected when it intersects detection level a, whereas the upward curve , it is detected when it intersects the detection level b, and as a result, a pulse-like waveform like the detection waveform is obtained. This detection waveform is sent to the I10 port 8, and further sent to the CPU 9 through the bus 14, where the detected portion is detected.

Problems to be Solved by the Invention As mentioned above, in conventional gap detection, the output voltage V out of the optical sensor 12 is directly used as the detection voltage. The output voltage Vout has a different value V1. V2, which causes variations in the output level of the detection voltage, and as a result, it is necessary to adjust the output level in advance using a variable resistor VR in order to correct this variation and make the output level constant. Similarly, during circuit operation, the output voltage Vout varies due to the temperature characteristics specific to the optical sensor 12 and the influence of disturbances, which causes the detection voltage to vary, and as a result, there is a risk that the gap detection circuit 1 may malfunction. .

Means to Solve the Problems Therefore, in order to solve these problems, the analog output detected by the optical sensor is converted into a time-divided digital output using an A/D converter. The differential value of the divided digital output data is determined, and the detected portion is detected based on the detected waveform of this differential value.

Therefore, detection of the detected parts such as gaps and notches is performed by the detection waveform of the differential value of the analog output of the optical sensor, so only the variation of the analog output is extracted as a signal, and the output characteristics of each optical sensor are detected. Even if the output level differs due to variations, there is no need to take into account the variation in the output level, so adjustment using a variable resistor is no longer necessary. The circuit will no longer malfunction due to inherent temperature characteristics or disturbances.

Embodiment An embodiment of the present invention will be described with reference to FIGS. 1 to 4 and 9 to 10.

The gap detection circuit 16 includes an optical sensor circuit section 1 that detects the gap 5 between the detected parts of the continuous paper 2 having different light transmittances, that is, the labels 4 attached to the mount 3 in FIG.
7, an A/D converter 18 for converting an analog waveform into a digital waveform, a RAM 19 for storing booter, and a Ro
M20 and CPU21 are provided. The optical sensor circuit section 17 includes one light emitting element (LED) 22 and a light receiving element (
It has a photosensor 24 consisting of a phototransistor) 23. The light emitting element 22 is connected to a power source Vc via a resistor R2.
On the other hand, the collector 25 side of the light receiving element 23 is connected to the power supply Vcc via a resistor R3. Further, the collector 25 side of the light receiving element 23 is connected to the A/D converter 18 located at the next stage, and the A/D converter 18 is connected to the A/D converter 18 located at the next stage.
The D converter 18 is connected to the CPU 21 through a bus 26. In addition, the RAM 19. Said ROM2
0 are each connected to the CPU 21 through the bus 26. Note that the notches 15 formed at equal intervals on one side edge of the mount 3 correspond to the detected portions in FIG.

In such a configuration, when the optical sensor 24 detects a detected part having a different light transmittance, the amount of light received by the light receiving element 23 changes, the voltage on the collector 25 side changes, and an analog waveform is applied to the collector 25 side. An output voltage Vout appears. The output voltage (output) of this analog waveform is time-divided by the A/D converter 18 at equal intervals "Δt" to form digital waveforms (S, S2, . . . ).

S, , ). :, ::i', RAM19. R
The following processing is performed using the OM20.

52S1=dt+di/Δt=D...(1
)S, -52=d, ,d,/Δt=D,...(2
) Sl Sl = da , d3/Δt = D3...
・(3) Ss Sl = d4 m (L /at
=D4...(4) Ss Ss "ds + d
s/at=D,...(5) s, ss==d,
-d, /Δt=D,... (6) S, -57=d,
, d, /Δt=D, ... (7) S, ss = d
, , d, /Δt=D, (8) Sl. -S,
==d, ,d, /Δ1=0. ...(9) S2
, -Sl. = d engineering. , dl. /Δt=D1゜...(1
0) Si, -S work□=d1□, d,, /Δt=D□,
...(11) Sl, -S, □=dzz, dtz/Δ
t=D1□...(12) S14-813=d11. d
l, /Δt=D1. ...(13) S 1s S
14 =dxs, dz4/Δt=Di,...(1
4) As mentioned above, first subtract S□ from S2 and get the difference d
, find. Next, the time Δt obtained by time-dividing this difference d1
By dividing by, the differential value D1 of equation (1) can be found. Similarly, the differential value (D2゜D
! ? ..., D14) is calculated. By determining the differential values (Dl, D, . . . , D14) in this manner, the amount and direction (+/-) of change in the output voltage V out can be investigated. Figure 4 shows the amount of change in this differential value and the direction of change (+/-).
Only the variation of the output voltage Vout in the figure appears. The differential value thus obtained is sent to the CPU 21 via the bus 26, and the detected portion is detected. Therefore, the detection signal obtained from the gap detection circuit 16 can be extracted without being affected by fluctuations in the output level of the output voltage Vout.

Effects of the Invention As described above, the present invention converts an analog output detected by an optical sensor into a time-divided digital output using an A/D converter, and calculates the differential value of the data of this time-divided digital output. Since the detected part is detected using the detected waveform of this differential value, it is only necessary to consider the variation of the analog output. There is no need to perform adjustment using a variable resistor even if the optical sensor is in use, and there is no need for the circuit to malfunction due to temperature characteristics specific to the optical sensor or disturbances during circuit operation.

[Brief explanation of the drawing]

1 to 4 show an embodiment of the present invention,
Figure 1 is a circuit diagram of the gap detection circuit, Figure 2 is a waveform diagram of the output voltage, Figure 3 is a waveform diagram of digital data, Figure 4 is a waveform diagram showing the amount of change in the differential waveform and its direction of change, Figures 5 to 8 show conventional examples, where Figure 5 is a circuit diagram of the gap detection circuit, Figure 6 is a waveform diagram of the output voltage, Figure 7 is a waveform diagram of the detection waveform, and Figure 8 is the output. Waveform diagrams showing the conditions when the voltage is different; Figure 9 is a plan view showing the gap between the label and the detected part on continuous paper; Figure 10 is a cutout between the label and the detected part on continuous paper. FIG. 2...Continuous paper, 5...Gap (detected part), 15
... Notch (detected part), 16... Gap detection circuit,
18...A/D converter, 24...light sensor output
Applicant: Tokyo Electric Co., Ltd., ¥), 1 Figure 7'' Liao 1 type) - , %, 3 Figure, %, u Figure, % 6 Figure (Part (9)) 1vl (branch)] -, % '7 Figure (flying) J) and) ■Carp) (wings) 8? + c)
−

Claims (1)

[Claims] In a label printer having an optical sensor that detects detected portions with different light transmittances on continuous paper, the analog output detected by the optical sensor is converted into time-divided digital output using an A/D converter. A label detection method for a label printer, characterized in that the differential value of the time-divided digital output data is determined, and the detected portion is detected using a detection waveform of the differential value.