JPH1016367A - Marker detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect marker positions correctly by discriminating the deviation of a relative level as a signal changing point, on the basis of a detection signal for detecting the marker positions of an ink ribbon. SOLUTION: The detecting signal of a marker is set in a NEW register 34a of a reading RAM 34, and at the timing of one former sampling, a determination is made whether or not an absolute value of the difference between it and the immediate data set in an OLD register exceeds a threshold value of noise to be stored in ROM 33. In the exceeding case, a determination is made whether or not the value of present data is greater than the value of the immediate data. In the case of a determination to be greater or smaller, the value of present data is set in MAX, MIN registers 34c, 34d, and then a determination is also made whether or not an absolute value of the difference between the maximum value and the minimum value of data value to be held in a MAX, MIN registers 34c, 34d exceeds the deviation threshold amount to be stored in ROM. Thus, in the exceeding case, changes are determined in a condition according to a presence and absence of detection of the marker position, then the content of a flag to be stored in the MARK register 34e of the RAM 34 is set reversely.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a marker detecting device for detecting a marker attached to an ink ribbon, particularly suitable for a printer using a color ink ribbon.

[0002]

2. Description of the Related Art FIG. 6 shows an example of a partial configuration of a serial color printer which is widely used. In the figure, 1
1 is a carriage table, 12 is a mechanical chassis of the printer apparatus, 13 is a ribbon marker sensor composed of a photocoupler provided on the carriage table 11, 14 and 14 are discharge rollers for feeding print paper, and 15 is the carriage table. A driving mechanism 16 for driving various parts of the printer apparatus, such as movement of 11 in the direction of arrow D, rotation of paper discharge rollers 14 and winding of an ink ribbon 17 described later, and 16 is mounted on the carriage base 11. Ink ribbon cassette, 17
Is an ink ribbon wound in the ink ribbon cassette 16.

The ribbon marker sensor 13 detects a black ink portion as a marker MK applied to a part of an ink ribbon 17 of an ink ribbon cassette 16 loaded on a carriage base 11 as shown in FIG. For this purpose, a detection circuit having the configuration shown in FIG. 8 is used.

That is, in FIG. 8, reference numeral 21 denotes a sensor unit including the ribbon marker sensor 13 shown in FIG.
An operating voltage V is applied via resistors R1 and R2, respectively. When the infrared light emitted from LED1 passes through the ink ribbon 17 and is received by the phototransistor Tr1, the analog output of the phototransistor Tr1 is output. Is sent to the Schmitt trigger gate circuit 22.

The Schmitt trigger gate circuit 22 binarizes the output signal from the sensor section 21 and sends it to the CPU 23 which controls the operation of the printer as a detection signal.

In the ink ribbon 17 shown in FIG. 7A, "Y" is yellow (yellow), "M" is magenta (magenta), and "C" is separated by markers MK, MK,. This is a primary color ink portion for cyan (blue).

When the markers MK, MK,... Are positioned on the ink ribbon 17 in the pattern shown in FIG. An analog signal having a simple waveform is output, and this is binarized by the Schmitt trigger gate circuit 22 using the threshold value TH, and as shown in FIG.
Ideally, a detection signal corresponding to K, MK,...

[0008]

However, in the circuit configuration shown in FIG. 8, the sensitivity actually varies due to the variation in the sensitivity of the sensor section 21, the thickness of the ink applied to the ink ribbon 17, and the like. Due to factors such as transmittance variation, the output of the sensor unit 21 is changed as shown in FIG.
It may be in the state as shown in FIG.

Therefore, even if the output of the sensor section 21 is binarized by the Schmitt trigger gate circuit 22,
An extremely inaccurate detection signal as shown in (5)
The CPU 23 will erroneously detect the marker MK.

To solve such a problem, as shown in FIG. 9, instead of the Schmitt trigger gate circuit 22 in the circuit configuration of FIG. 8, a comparator 24 capable of adjusting a reference potential by a variable resistor VR1 is provided. This is now widely used as a circuit for detecting a marker in a general word processor printer.

With the circuit configuration shown in FIG. 9, the threshold value TH is adjusted for the output of the sensor section 21 as shown in FIG.
As a result, it is possible to obtain a detection signal that accurately corresponds to the position of the marker MK as shown in (3), and it is possible to deal with variations in the characteristics of the elements constituting the sensor unit 21.

However, in rare cases, the transmittance of the ink ribbon 17 varies along its longitudinal direction due to unevenness in the thickness of the applied ink, and the output of the sensor unit 21 is changed as shown in FIG. The reference level may fluctuate as shown.

In such a case, no matter how the threshold value TH is adjusted by the variable resistor VR1 in the comparator 24, an extremely inaccurate detection signal as shown in FIG. Then marker M
K will be erroneously detected.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to deal with a case where a detection signal for detecting a marker position on an ink ribbon fluctuates based on various factors. Another object of the present invention is to provide a marker detection device capable of removing these effects and accurately detecting the marker position.

[0015]

According to the first aspect of the present invention,
An apparatus for detecting a marker attached to an ink ribbon that moves in a longitudinal direction by a moving means, wherein the detecting means optically reads the marker on the ink ribbon and outputs a corresponding electric signal, and the detecting means. Means for converting an electrical signal output from the controller into a digital data value at fixed time intervals, and first determining means for sequentially determining the magnitude of the latest data value obtained by the converting means and the data value immediately before it A first storage means for sequentially updating and storing the latest data value when the first determination means determines that the latest data is larger; and a first data means for sequentially updating and storing the latest data value. Is smaller, the second storage means for sequentially updating and storing the latest data value, and one of the data values stored in the first storage means or the second storage means is Each time a new value is updated, a second determining means for determining the magnitude of a difference between a data value stored in the first storage means and the data value stored in the second storage means and a predetermined reference value; And a marker discriminating means for discriminating a marker in accordance with the judgment result of the judging means.

With this configuration, even if the detection signal for detecting the marker position of the ink ribbon fluctuates due to various factors, the deviation of the relative level can be changed by a signal processing by software. By identifying them as points, these effects can be removed and the marker position can be accurately detected.

According to a second aspect of the present invention, in the first aspect of the present invention, the difference between the latest data value obtained by the conversion means and the immediately preceding data value is smaller than the predetermined reference value. A third determining means for sequentially determining the magnitude of the set value, and only when the third determining means determines that the difference between the latest data value and the immediately preceding data value is smaller, Control means for stopping the determination operation of the first determination means and the second determination means and updating and storing the latest data values in the first storage means and the second storage means, respectively. And

With such a configuration, in addition to the operation of the first aspect of the present invention, a minute shift component caused by noise or the like is removed, and only the latest data value is updated and stored. Therefore, the marker position can be detected more accurately by removing the influence of noise or the like.

According to a third aspect of the present invention, there is provided an apparatus for detecting a marker attached to an ink ribbon which is moved in a longitudinal direction by a moving means, wherein the marker on the ink ribbon is optically read and a corresponding electric signal is read. Detecting means for outputting a signal; holding means for holding the peak value of the electric signal outputted from the detecting means at a fixed value lowered; and an electric signal outputted from the detecting means based on the held contents of the holding means. And comparing means for comparing the magnitudes of the two and outputting the comparison result as a marker discrimination signal.

With such a configuration, even when a detection signal for detecting the marker position of the ink ribbon fluctuates due to various factors, the relative level deviation is detected by the hardware circuit as a signal change. By identifying them as points, these effects can be removed and the marker position can be accurately detected.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) A first embodiment of the present invention will now be described with reference to the drawings.
An embodiment will be described. FIG. 1 shows the circuit configuration, and the configuration of the sensor section 21 itself is the same as that shown in FIGS. 8 and 9, and the description thereof will be omitted using the same reference numerals.

The detection signal of the analog value output from the sensor unit 21 is sent to the A / D converter 31. The A / D converter 31 is supplied with a voltage + V as the upper reference voltage VRH and a ground level as the lower reference voltage VRL, and converts a detection signal from the sensor unit 21 to a predetermined sampling frequency, for example, 1 [kHz]. ], And the number of quantization bits, for example, 8 bits, and the digital data is transmitted to the CPU 32.

The CPU 32 includes a ROM 33 and an R
AM34 is connected, and based on an operation program fixedly stored in the ROM 33 and a constant threshold, R
While writing / reading data to / from the AM 34 as appropriate, processing is executed to detect the marker position applied to the ink ribbon 17.

In the ROM 33, as a constant threshold value,
A noise threshold value α for determining a shift due to data noise and a shift amount threshold value β for determining a shift due to a marker position are stored.

In the RAM 34, the latest value NEW of the data value obtained by the A / D converter 31, the same value OLD immediately before, the maximum value MAX of the data values input so far, and the data input so far. Each of the registers 34a to 34e for storing the minimum value MIN of the data values and the change mark flag MARK indicating the marker detection state is set.

The operation of the above configuration is as follows. FIG. 2 shows the contents of the interrupt processing for marker detection performed by the CPU 32 every 1 [mS] in response to the sampling clock to the A / D converter 31 during the printing operation. Reads the digital value detection signal sent from the D converter 31 and stores it in the RAM.
34 is set in the NEW register 34a (step S
1). In this case, since the detection signal to be set is 8 bits, the range is from 00H to FFH.

Next, the noise threshold stored in the ROM 33 is the absolute value of the difference between the current data value set in the NEW register 34a and the immediately preceding data value set in the OLD register 34b at the previous sampling timing. It is determined whether or not the value exceeds the value α, that is, whether or not the amount of deviation between the current data value and the immediately preceding data value exceeds a minute value due to noise or the like (step S2).

Here, the noise threshold value α is not exceeded,
If it is determined that the amount of deviation between the current data value and the immediately preceding data value is only minute due to noise or the like,
Regardless of the magnitude relationship between the current data value and the previous data value,
The current data value is set as initialization in both the MAX register 34c and the MIN register 34d (step S
9) Then, the current data value is set again in the OLD register 34b for the next sampling (step S8), and the CPU 32 ends this process and returns to another process such as a print operation. .

In step S2, the absolute value of the difference between the current data value and the immediately preceding data value exceeds the noise threshold value α, and therefore, the deviation between the current data value and the immediately preceding data value is determined. If it is determined that the amount of transfer exceeds a minute amount due to noise or the like, then whether the current data value is larger than the immediately preceding data value, that is, the current data value is compared with the immediately preceding data value It is determined whether it is increasing or decreasing (step S3).

If it is determined that the current data value is larger than the immediately preceding data value, the signal has risen, so the current data is set in the MAX register 34c (step S5), and conversely. If it is determined that the current data value is smaller than the immediately preceding data value, the signal is falling, and the current data is set to MIN.
The value is set in the register 34d (step S4).

In this way, MIN in step S4 or S5
After updating the contents of the register 34d or the MAX register 34c, the absolute value of the difference between the maximum value of the data value held in the MAX register 34c and the minimum value of the data value held in the MIN register 34d is: ROM3
3 whether or not the deviation threshold value β stored in
That is, it is determined whether or not the state is changed due to the presence or absence of the detection of the marker position (step S6).

Here, it is assumed that the absolute value of the difference between the maximum value and the minimum value of the data values so far exceeds the shift amount threshold value β, and therefore, the state changes with the presence or absence of the marker position detection. Only when the determination is made, the flag is inverted to "0" if the flag content stored in the MARK register 34e of the RAM 34 is "1" and to "1" if it is "0" (step S7).

Thereafter, the current data value is set again in the OLD register 34b for the next sampling (step S8), and the CPU 32 ends this processing and returns to another processing such as a printing operation. .

The noise threshold α and the deviation threshold β stored in the ROM 33 are operating parameters.
This is to set an appropriate value corresponding to the characteristics of the printer device to be used.
Is set to 19H corresponding to 10% of the voltage + V, and 99H corresponding to 60% of the voltage + V is set to the shift amount threshold β.

FIG. 3 illustrates a specific marker detection operation based on the above-described processing. Fig. 3 (1)
When there is an ink ribbon 17 to which the markers MK, MK are attached as shown in FIG.
An analog waveform as shown in (2) is obtained.

It is assumed that the data value obtained by digitizing this detection signal by the A / D converter 31 has the content as shown in FIG. In this case, the minimum value that can be taken within the range is 00H and the maximum value is 99H as shown in the figure.

However, in the data value of FIG. 3 (3), if the shift amount exceeds the shift amount threshold value β, the MARK register 34e shown in FIG. And the MARK register 34 for a shift such as N shown in the figure, in which the amount of the shift is less than or equal to the noise threshold α.
The flag state of e does not change. In this case, at each timing when the flag state of the MARK register 34e is set to be inverted, the delay times tu and td are generated after the data value starts shifting until it is determined that the data value has actually shifted. This is related to the setting of the shift amount threshold value β, and it is necessary to adjust and set an appropriate value corresponding to the characteristics of the printer used.

As described above, by the processing of the software executed by the CPU 32, while removing a small shift component caused by noise or the like, a large shift at a relative level is identified as a signal change point. By removing these effects, the marker position can be accurately detected.

(Second Embodiment) Next, the case where the first embodiment is realized by a hardware circuit will be described with reference to the second embodiment of the present invention and the drawings.

FIG. 4 shows the circuit configuration. The configuration of the sensor section 21 itself is the same as that shown in FIGS. 8, 9 and 1, and the description thereof will be omitted using the same reference numerals. I do.

However, the analog value detection signal output from the sensor section 21 is an NPN type transistor Tr.
This transistor Tr2 applied to the base of
The voltage + V is applied to the collector, the emitter is grounded via the resistor R3, and is connected to the anode of the diode D1 and one end of the resistor R6.

The cathode of the diode D1 is connected to the other end of the resistor R5 having one end grounded, the other end of the capacitor C1 having one end grounded, and the comparator 4 via the resistor R4.
The other end of the resistor R6 is connected to the + input terminal of the comparator 41.

The output terminal of the comparator 41 is a resistor R
7 is positively connected to the + input terminal via a resistor 7, a voltage + V is applied to the output terminal via a resistor R8, and the potential V0 is used as a detection result corresponding to the flag content of the MARK register 34e. Is what is done.

In the above-described circuit configuration, the transistor Tr2 and the resistor R3 perform impedance conversion of an analog value detection signal output from the sensor unit 21.
The circuit including the diode D1, the resistor R4, the resistor R5, and the capacitor C1 that receives the result of the impedance conversion forms a kind of peak hold circuit that holds the peak value of the signal in a state reduced by a certain value. Things.

The value held by the peak hold circuit is input to the negative input terminal of the comparator 41 as a reference signal reflecting the relative shift of the detection signal. The hold time th is represented by the following equation: th = C1 · R5 (1), and the markers MK,
The peak hold circuit corresponds to the update setting processing of the MAX register 34c or the MIN register 34d in steps S3 to S5 in FIG. Is what you do.

However, at the + input terminal of the comparator 41 indicated by the point C in the drawing, a positive feedback connection is made with the point D of the output terminal of the comparator 41 via the resistor R7 in order to give the compared signal a hysteresis characteristic. The feedback voltage Vh is expressed by the following equation: Vh = (R6 / (R6 + R7)). (V0H-V0L) (2), and the potential at the point D changes from "H" level to "H". When changing to L level and when changing from L level to H level
When the level changes, the threshold value is changed to prevent malfunction due to noise or the like.
This corresponds to the point that the judgment processing for removing the minute deviation in step S2 in FIG. 2 and the separate processing corresponding to the rise and fall of the signal waveform are performed in steps S3 to S5. It is.

FIG. 5 shows the circuit configuration as described above.
The same markers MK, MK, and MK as shown in FIG.
Each signal waveform is shown when marker detection is performed on the ink ribbon 17 marked with...

In this case, as shown in FIG. 5A, the output of the sensor unit 21 was obtained by impedance conversion of the ink ribbon 17 by the transistor Tr2 and the resistor R3.
The signal indicating the potential at the point A has a waveform as indicated by a thick solid line in FIG.

Therefore, when the peak value is held while lowering the level of this signal by a fixed value in the peak hold circuit, the held value which is the potential at point B is as shown in FIG.
The waveform shown by the broken line in (2) is obtained.

On the other hand, the signal which is the potential at the point C input to the + input terminal of the comparator 41 has a waveform as shown by a dashed line in FIG. 5 (2). Therefore, the voltage V0 at the point D, which is the output terminal of the comparator 41, is
As shown in (3), the markers MK, M
K,... Can be used as detection signals accurately corresponding to K,.

As described above, even by a hardware circuit, a small shift component caused by noise or the like is removed, and a large shift is identified as a signal change point at a relative level, thereby eliminating these effects. Although the marker position can be removed and the marker position can be accurately detected, a dedicated circuit configuration is required. On the other hand, the burden on the CPU 32 that controls the operation of the printer device can be reduced.

7 (1) and FIG. 5 (1), as shown in the figure, the patterns of the markers MK, MK,.
(Magenta) "and between" M (magenta) "and" C
(Cyan) ", between" Y (yellow) "and the preceding" C (cyan) ", and between" C (cyan) "and the next" Y (yellow) ". The printing is performed repeatedly in a certain range with “Y (yellow)”, “M (magenta)”, and “C (cyan)” as a set. belongs to.

The present invention is not limited to the above-described first and second embodiments, but can be variously modified and implemented without departing from the gist thereof.

[0054]

According to the first aspect of the present invention, even if the detection signal for detecting the marker position of the ink ribbon fluctuates based on various factors, the relative level shift is performed by software processing. Is identified as a signal change point, thereby removing these effects and accurately detecting the marker position.

According to the second aspect of the present invention, in addition to the effect of the first aspect of the present invention, a minute shift component due to noise or the like is removed and only the latest data value is updated and stored. Accordingly, the marker position can be detected more accurately by removing the influence of noise or the like.

According to the third aspect of the present invention, even when the detection signal for detecting the marker position of the ink ribbon fluctuates based on various factors, the deviation of the relative level is signaled as a hardware circuit. By identifying the marker position as a change point, these effects can be removed and the marker position can be accurately detected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation according to the embodiment.

FIG. 3 is a timing chart illustrating an operation according to the embodiment.

FIG. 4 is a diagram showing a circuit configuration according to a second embodiment of the present invention.

FIG. 5 is a timing chart illustrating an operation according to the embodiment.

FIG. 6 is a diagram showing a partial configuration of a general serial printer device.

FIG. 7 is a timing chart illustrating a signal waveform of marker detection in the device of FIG. 6;

FIG. 8 is a block diagram illustrating a circuit configuration of marker detection in the device of FIG. 6;

FIG. 9 is a block diagram illustrating another circuit configuration of marker detection in the device of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Carriage stand 13 ... Ribbon marker sensor 16 ... Ink ribbon cassette 17 ... Ink ribbon 21 ... Sensor part 22 ... Schmitt trigger gate circuit 23 ... CPU 24 ... Comparator 31 ... A / D converter 32 ... CPU 33 ... ROM 34 ... RAM 34a ... NEW register 34b ... OLD register 34c ... MAX register 34d ... MIN register 34e ... MARK register 41 ... Comparator MK ... Marker

Claims (3)

[Claims] 1. An apparatus for detecting a marker attached to an ink ribbon which is moved in a longitudinal direction by a moving means, wherein the detecting means optically reads the marker on the ink ribbon and outputs a corresponding electric signal. Conversion means for converting an electric signal output from the detection means into a digital data value at regular time intervals; and sequentially determining the magnitude of the latest data value obtained by the conversion means and the data value immediately before it. First determining means; first storing means for sequentially updating and storing the latest data value when the first determining means determines that the latest data is larger; and the first determining means When it is determined that the latest data is smaller, the second storage means sequentially updates and stores the latest data value, and the latest data value is stored in the first storage means or the second storage means. Every time one of the data values is updated, a second determination means for determining the magnitude of a difference between the two data values stored in the first storage means and the second storage means and a predetermined reference value And a marker discriminating means for discriminating a marker in accordance with the result of the judgment by the second judging means. 2. A third determination for sequentially determining the magnitude of a difference between a latest data value obtained by the conversion means and a data value immediately before the latest data value and a value set to be smaller than the predetermined reference value. Means only when it is determined by the third determination means that the difference between the latest data value and the immediately preceding data value is smaller.
Control means for stopping the determination operation of the first determination means and the second determination means and updating and storing the latest data values in the first storage means and the second storage means, respectively. The marker detection device according to claim 1, wherein 3. An apparatus for detecting a marker attached to an ink ribbon moved in a longitudinal direction by a moving means, wherein the detecting means optically reads the marker on the ink ribbon and outputs a corresponding electric signal. And holding means for holding the peak value of the electric signal output from the detecting means lowered by a certain value, and comparing the magnitude of the electric signal output from the detecting means with reference to the held contents of the holding means, And a comparing means for outputting the comparison result as a marker discrimination signal.