JP5307595B2 - Label printer, paper cueing position control method and program - Google Patents

Description

  The present invention relates to a label printer that performs printing by pulling out a mount wound in a roll with a stacked sheet from the roll, and in particular, even if the sheet leading mark is shaded or a perforation is formed on the mount. The present invention relates to a label printer that can accurately perform cueing.

  The label printer performs printing by pulling out a mount wound in a roll shape together with the loaded paper from the roll. For this reason, a detection sensor is provided to detect that the leading edge of the paper has reached a predetermined position. With this, the position of the paper is detected by detecting the mark provided on the mount or the edge of the paper with the sensor. Deciding.

  FIG. 15 shows an example of mark reading. When the mark passes through the detection sensor, the output value of the sensor gradually increases, and the sensor output value becomes maximum at the center of the mark. Then, the sensor output value gradually decreases and returns to the original output level. The output waveform of the sensor is substantially the object around the central part of the mark. The comparator is turned on when the sensor output value exceeds a predetermined threshold value, and turned off when the sensor output value falls below the predetermined threshold value.

  The invention disclosed in Patent Document 1 improves the mark detection accuracy by obtaining a new threshold value based on the maximum and minimum values of the output of the detection sensor and the current threshold value.

  By the way, some rolls have perforations on the mount. FIG. 16 shows an example of an operation for reading a mark on a mount on which a perforation is formed. When the perforation passes the detection sensor, the sensor output value increases, and when the mark passes the detection sensor, the sensor output value becomes maximum without returning to the original output level. Then, the sensor output value gradually decreases and returns to the original output level.

  At this time, if the threshold value for turning on the comparator is set high as shown in FIG. 16, the period during which the comparator is turned on coincides with the timing at which the mark passes the detection sensor, and thus the position of the sheet is accurately detected. It is possible.

  However, if the threshold value at which the comparator is turned on is set high, the sensor output value may not exceed the threshold value due to variations in the density of the mark. In this case, the page is missing without detecting the paper. End up.

  In order to prevent this, if the threshold value for turning on the comparator is set low as shown in FIG. 17, marks including the perforation are detected, and the paper position cannot be detected accurately.

There is an invention disclosed in Patent Document 2 as an invention relating to enabling accurate detection of a mark even if the mark is shaded or a perforation is formed on the mount.
In the invention disclosed in Patent Document 2, the maximum value of the detection sensor output is always checked, and the correction amount is calculated from the maximum value to obtain the variation. The position of the mark can be accurately detected even if it is.

Japanese Patent Laid-Open No. 06-191526 JP 2008-238606 A

  However, the invention disclosed in Patent Document 2 is configured by using a high-sensitivity sensor, a high-speed A / D converter, or a high-performance device such as a CPU in order to constantly check the maximum value of the output of the detection sensor. There is a need to. In general, high-performance devices are expensive, which increases the cost of parts of the label printer.

  SUMMARY An advantage of some aspects of the invention is that it provides a label printer, a paper cue position control method, and a program that can accurately cue paper without using a high-performance device.

  In order to achieve the above object, the present invention provides, as a first aspect, a sensor that detects the black level of a sheet every time the sheet is conveyed by a unit amount, and is turned on when an output value of the sensor becomes a predetermined value or more. A comparator output that is turned off when the output value of the sensor is less than a predetermined value, and a sensor output value that records the output value of the sensor for each unit amount when the paper is conveyed for a predetermined distance for at least one predetermined distance of conveyance. Recording means, means for determining a threshold value as a predetermined value based on the sensor output value recorded in the sensor output value recording means, and the sensor output value recorded in the threshold value and sensor output value recording means Based on the above, the first distance, which is the distance between the position on the sheet where the sensor output value is equal to or greater than the threshold and the position on the sheet where the sensor output value is maximum, and the position on the sheet where the sensor output is equal to or greater than the threshold Position and sensor output Means for calculating a ratio with a second distance that is an interval from a position on the paper whose value is less than the threshold, and a position on the paper where the sensor output is equal to or greater than the threshold and the sensor output value are less than the threshold during printing The present invention provides a label printer characterized by having means for determining a paper cueing position by multiplying the distance to the position on the paper by a ratio.

  In order to achieve the above object, according to a second aspect of the present invention, a sensor for detecting the black level of the paper every time the paper is transported by a unit amount, and an ON value when the output value of the sensor exceeds a predetermined value. A method for controlling the cueing position of a label printer having a comparator that is turned off when the output value of the sensor is less than a predetermined value, wherein the output value of the sensor for each unit amount when the paper is conveyed by a predetermined distance Is stored in at least one conveyance distance sensor output value recording means for a predetermined distance, a threshold value is determined as a predetermined value based on the accumulated sensor output value, and the threshold value and the accumulated sensor output value are Based on the first distance, which is the distance between the position on the paper where the sensor output value is equal to or greater than the threshold and the position on the paper where the sensor output value is maximum, and the position on the paper where the sensor output is equal to or greater than the threshold. And sensor output value The ratio between the second distance, which is the distance from the position on the paper that is less than the threshold, is calculated, and the position on the paper where the sensor output is greater than or equal to the threshold and the sensor output value is less than the threshold during printing The present invention provides a paper cue position control method characterized by determining a paper cue position by multiplying a distance to an upper position by a ratio.

  In order to achieve the above object, according to a third aspect of the present invention, a computer for controlling the operation of the label printer is caused to execute the paper cueing position control method according to the second aspect of the present invention. The present invention provides a paper cueing position control program.

  According to the present invention, it is possible to provide a label printer, a paper cueing position control method, and a program that can accurately cue paper without using a high-performance device.

1 is a diagram showing a schematic configuration of a label printer according to a preferred embodiment of the present invention. FIG. 6 is a diagram illustrating a configuration of a paper leading edge detection function unit. It is a figure which shows the flow of a sensor threshold value adjustment process. It is a figure which shows the flow of a sensor output table formation process. It is a figure which shows the structure of a sensor recording table. It is a figure which shows the flow of a threshold value calculation process. It is a figure which shows the flow of a table scanning process. It is a figure which shows the flow of a table scanning process. It is a figure which shows the flow of a table scanning process. It is a figure which shows the flow of a ratio calculation process. It is a figure which shows the flow of a ratio calculation process. It is a figure which shows the relationship of each variable. It is a figure which shows the flow of a paper cue determination process. It is a figure which shows the relationship between a thermal head-detection sensor distance, a correction amount, and a cueing stop position. It is a figure which shows an example of the sensor output at the time of mark detection, and a comparator output. It is a figure which shows an example of the sensor output at the time of mark detection in case a perforation exists in a mount, and a comparator output. It is a figure which shows an example of the sensor output at the time of mark detection in case a perforation exists in a mount, and a comparator output.

A preferred embodiment of the present invention will be described.
FIG. 1 shows a schematic configuration of a label printer according to the present embodiment.
The paper drawn from the roll 1 is sandwiched between the thermal head 2 and the platen roller 3 and is conveyed along with the rotation of the platen roller 3 driven by a stepping motor (not shown). A detection sensor 4 is provided on the paper conveyance path between the roll 1 and the thermal head 2 so that the mark paper front end mark displayed on the mount can be detected. Although FIG. 1 shows a configuration in which a light emitting unit and a light receiving unit are arranged across a paper conveyance path assuming a transmission type optical sensor, a reflection type optical sensor may be used. Needless to say. The output of the detection sensor 4 is input to the paper leading edge detection function unit 5. The paper leading edge detection function unit 5 cues the paper based on the detection result of the detection sensor 4.

FIG. 2 shows the configuration of the paper leading edge detection function unit 5. The paper leading edge detection function unit 5 includes an A / D converter 51 for digitizing the output value of the detection sensor 4, a memory area 52 for storing the digitized output value of the detection sensor 4 in a table, and history storage. Based on the sensor output value, the sensor threshold adjustment processing unit 53 that calculates the threshold and the ratio, the D / A converter 54 that converts the threshold generated by the sensor threshold adjustment processing unit 53 into an analog value, and the output value of the detection sensor 4 The comparator 55 is turned on when it is equal to or more than the analog threshold value, and is turned off when the threshold value is lowered. The paper cueing determination processing unit 56 judges the paper cueing position based on ON / OFF of the comparator.
The threshold adjustment processing unit 56 and the paper cueing determination processing unit 53 can be realized in an arithmetic processing unit such as a CPU by software processing by a computer.

The operation of the paper leading edge detection function unit 5 will be described. FIG. 3 shows an operation flow of the sensor threshold value adjustment processing unit 53. The sensor threshold value adjustment process performed by the sensor threshold value adjustment processing unit 53 is a process of determining a ratio for obtaining the threshold value of the detection sensor and the paper cueing position.
The sensor threshold value adjustment processing unit 53 first initializes variables (step S11), subsequently performs sensor output table processing (step S12) and threshold value calculation processing (step S13), and sets the calculated threshold value to ON / OFF of the comparator. It sets as a threshold value to switch (step S14).

FIG. 4 shows the flow of the sensor output table processing.
First, the stepping motor is driven one step (step S101), and the output value of the detection sensor is read through the A / D converter (step S102). The threshold adjustment processing unit 53 compares the set maximum value Ymax with the read value (step S103). If the read value is larger (step S103 / Yes), the maximum value Ymax is updated (step S104). ). When the read value is Ymax or less (step S103 / No), the minimum value Ymin is compared with the read value (step S105). If the read value is smaller (step S105 / Yes), the minimum value Ymin is updated (step S106). When the read value is Ymin or more (step S105 / No), Ymin is not updated.

  Thereafter, in order to save the history of reading values, the reading values are arranged in time series as shown in FIG. 5 and stored in the memory area 52 as a sensor recording table (step S107).

  Thereafter, it is determined whether or not the stepping motor has been driven by a predetermined distance in order to determine a threshold value for switching ON / OFF of the comparator 55 (whether the number of steps has reached a predetermined value) (step S108). If the predetermined value has not been reached (step S108 / No), the number of steps is counted up (step S109), and the stepping motor is driven again (step S101). If the predetermined value has been reached (step S108 / Yes), the sensor output table creation process is terminated.

FIG. 6 shows a flow of threshold value calculation processing.
An intermediate value Ymin is obtained from the maximum value Ymax and the minimum value Ymin obtained in the sensor output table process, and is set as a temporary threshold Ymid (step S201). Thereafter, the stored sensor recording value table is scanned to execute a table scanning process for obtaining sensor threshold values from a plurality of paper cueing positions (step S202).

7 to 9 show the flow of the table scanning process.
In order to obtain the maximum value Ymax1 and minimum value Ymin1 of the first sheet cueing position, the first value of TBl is stored as the minimum value Ymin1 (step S301), and the temporary threshold Ymid is stored as the maximum value Ymax1 (step S302). ). Then, 1 is set to the step number α as a counter to perform table scanning (step S303).
First, in order to obtain the minimum value Ymin1, the current table value is compared with Ymin1 (step S304), and if the table value is smaller, it is replaced (step S305). Next, 1 is added to the counter step number α (step S306), and then, it is compared whether the table value is equal to or larger than the temporary threshold Ymid (step S307). If the table value is not equal to or greater than the temporary threshold value (step S307 / No), there is a possibility that the mark is located away from the detection sensor 4. In a state where the mark is away from the detection sensor 4, the output value of the detection sensor varies at a low level, and therefore there is a possibility that the minimum value Ymin1 is updated. Therefore, if the table value does not exceed the provisional threshold, the minimum value Ymin1 may still be updated, so the process proceeds to step S304 and the process is repeated.
If the table value is equal to or greater than the temporary threshold Ymid (step S307 / Yes), the position is the position where the paper cueing detection is started, and it is difficult to assume that the minimum value Ymin1 is updated thereafter. The value Ymin1 is fixed, and the process proceeds to a process for detecting the maximum value Ymax1.

  In the process of detecting the maximum value Ymax1, first, the table value is compared with Ymax1 (step S308), and if the table value is larger (step S308 / Yes), Ymax1 is updated (step S309). Next, the counter step number α is incremented by 1 (step S310), and it is determined whether or not the table value is equal to or less than the temporary threshold Ymid (step S311).

If the table value is larger than the temporary threshold Ymid (step S311 / No), there is a possibility that the maximum value Ymax1 is still updated, so that the process proceeds to step S308 and the process is repeated.
If the table value is equal to or less than the temporary threshold Ymid (step S311 / Yes), the maximum value Ymax1 is determined because the paper cueing detection end position is reached.

Next, in order to obtain the maximum value Ymax2 and minimum value Ymin2 of the second paper cueing position, the temporary threshold Ymid is stored in the minimum value Ymin2 (step S312), and the temporary threshold Ymid is also stored in the maximum value Ymax2 (step S312). Step S313).
Steps S314 to S321 are processes for obtaining the second maximum value and the minimum value, and the processes in each step are the same as those in steps S304 to S311.

  Thereafter, Ymin is obtained as the average of the two obtained minimum values (step S322), Ymax is obtained as the average of the two maximum values (step S323), and the table scanning process is terminated.

Returning to FIG. 6, the continuation of the threshold value calculation process will be described. A threshold Ymid is determined based on Ymin and Ymax obtained in the table scanning process S202 (step S203).
Next, a ratio calculation process for obtaining a ratio for determining the paper cueing position is executed from the position of the maximum value of each paper cueing position and the position where the comparator ON / OFF is switched at Ymid determined in step S203 ( Step S204).

10 and 11 show the flow of the ratio calculation process.
A step number α as a counter for scanning the table is set to 0 (step S401). Then, in order to obtain a position that is larger than the threshold Ymid (the comparator output is turned on), it is compared with a table value (step S402). If the table value is smaller (step S402 / No), 1 is added to the step number α (step S403), and the next table value is compared with the threshold value Ymid (step S402).
If the table value is equal to or greater than the threshold value Ymid (step S402 / Yes), the position where the table value is equal to or greater than the threshold value Ymid is stored. Therefore, the value of the step number α is stored in the variable β, and the maximum value Ymax is set to the threshold value Ymid. Initialization is performed (step S404).

  Next, in order to obtain the position of the sensor output maximum value, the table value is compared with the maximum value Ymax (step S405). If the table value is larger (step S405 / Yes), Ymax is updated and the position is updated. The variable γ is stored (step S406).

  The processes in steps S405 and S406 are repeated until the table value falls below the threshold value Ymid (the comparator output value becomes OFF) (steps S407 and S408).

  FIG. 12 shows the relationship between each variable. The variable β indicates the position of the place where the table value is equal to or greater than the threshold value Ymid (in other words, the position where the comparator 55 is turned on). The variable γ indicates the position of the place where the sensor output is maximum. The variable α indicates the position of the place where the table value is equal to or less than the threshold value Ymid (in other words, the position where the comparator 55 is turned off).

  From the obtained variable β, variable γ, and step number α, the ratio σ1 between the distance 1 at which the comparator for the first paper cueing position is turned on and the distance 2 at which the sensor output value maximum position is obtained is obtained (step S409). .

  Next, the ratio σ2 between the distance 3 at which the comparator is turned ON and the distance 4 at which the sensor output value is at the maximum position is obtained by the same procedure as steps S402 to S409 (steps S410 to S417).

  Thereafter, a sheet cueing position ratio σ is obtained as an average of the ratios σ1 and σ2 (step S418).

  The paper cue position ratio σ is set as described above, and during actual printing, the paper cue determination processing unit 56 performs a paper cue determination process described below using the set σ.

FIG. 13 shows a flow of paper cueing determination processing.
First, the stepping motor is driven one step (step S501), and the output value of the comparator is read (step S502). Then, in order to determine whether the comparator is already ON, the state of the paper head detection flag that is ON when the comparator is ON is confirmed (step S503). If the comparator has not been turned on yet (the paper head detection flag is OFF) (step S503 / Yes), it is determined whether or not the read value is ON (step S504).
If the read value is ON (step S504 / Yes), the paper head detection flag is set to ON (step S505), and the counter is cleared to zero to determine the distance at which the comparator is ON (step S506). Thereafter, the paper cueing determination process is temporarily exited, and when it is executed again, the process is restarted from step S501.

  If the paper head detection flag is ON (the comparator is already ON) (step S503 / No), the counter is incremented by 1 (step S507), and the distance is updated. Then, it is determined whether or not the read value is OFF (step S508). If the read value is OFF (step S508 / Yes), the paper head detection flag is cleared (step S509). Then, the distance at which the comparator is turned on is obtained based on the value of the counter, and the cue position is calculated from the value obtained by multiplying the counter by the ratio σ (step S510). As shown in FIG. 14, the cue position corresponds to the center position of the mark. Further, the paper cueing determination processing unit 56 subtracts the cueing position from the counter value to obtain a correction amount (step S511). As shown in FIG. 14, the correction amount corresponds to the distance from the center of the mark to the rear end of the mark. By subtracting this correction amount from the distance between the thermal head 2 and the detection sensor 4, the cue stop amount is obtained (step S512). As shown in FIG. 14, the cue stop amount is an amount indicating how much the sheet is fed after the mark passes the detection sensor 4 and the print start position reaches the thermal head 2. This makes it possible to start printing from the correct position.

  As described above, the label printer according to the present embodiment can accurately cue the paper even if the paper front end mark is shaded or a perforation exists in front of the paper front end mark. In addition, since only the paper cueing determination process is performed in actual printing, it is not necessary to use a high-sensitivity sensor, a high-speed A / D converter, or a high-performance device such as a CPU. Can be prevented.

In addition, the said embodiment is an example of suitable implementation of this invention, and this invention is not limited to this.
For example, in the above-described embodiment, the maximum value and the minimum value are obtained, a threshold value serving as a reference for switching ON / OFF of the comparator based on the two values, the distance at which the comparator is ON, and the distance at which the sensor output value is the maximum position Although an example is shown in which the average is calculated by obtaining two ratios, the average may be calculated by obtaining three or more thresholds and ratios from three or more maximum values and minimum values.
As described above, the present invention can be variously modified.

DESCRIPTION OF SYMBOLS 1 Roll 2 Thermal head 3 Platen roller 4 Detection sensor 5 Paper front-end detection functional part 51 A / D converter 52 Memory area 53 Sensor threshold value adjustment process part 54 D / A converter 55 Comparator 56 Paper heading judgment process part

Claims (9)

A sensor that detects the black level of the paper each time the paper is transported by a unit amount;
A comparator that is turned on when the output value of the sensor is equal to or greater than a predetermined value, and that is turned off when the output value of the sensor is less than the predetermined value;
Sensor output value recording means for recording the output value of the sensor for each unit amount when the paper is transported by a predetermined distance for at least one transport of the predetermined distance;
Means for determining a threshold value as the predetermined value based on the output value of the sensor recorded in the sensor output value recording means;
Based on the threshold value and the sensor output value recorded in the sensor output value recording means, the position on the sheet at which the sensor output value is equal to or greater than the threshold value and the sheet at which the sensor output value is maximized A first distance that is an interval from the upper position, and a position between the position on the sheet at which the sensor output is equal to or greater than the threshold and the position on the sheet at which the sensor output value is less than the threshold. Means for calculating a ratio to a distance of 2;
When printing, a paper cueing position is obtained by multiplying the distance between the position on the paper where the sensor output is greater than or equal to the threshold and the position on the paper where the sensor output value is less than the threshold by the ratio. And a label printer. During printing, the distance between the position on the paper where the sensor output is greater than or equal to the threshold and the position on the paper where the sensor output value is less than the threshold, and the output value of the sensor is greater than or equal to the threshold The difference from the paper position to the paper cue position is calculated as a correction amount,
The label printer according to claim 1, wherein a difference between a distance between a print head that performs printing on the sheet and the sensor and the correction amount is a conveyance amount of the sheet at the time of printing. The output value of the sensor for each unit amount is recorded in the sensor output value recording means for two or more conveyances of the predetermined distance,
3. The label printer according to claim 1, wherein an average is taken for each of the threshold value and the ratio for each time calculated based on the output value of the sensor for each unit amount each time.   4. The method according to claim 1, further comprising a counter that counts the number of driving of the stepping motor that transports the paper, and measures the transport amount of the paper based on a count value of the counter. Label printer. A sensor that detects the black level of the paper each time the paper is transported by a unit amount;
A paper cueing position control method in a label printer having a comparator that is turned on when the output value of the sensor is equal to or greater than a predetermined value and turned off when the output value of the sensor is less than the predetermined value,
The output value of the sensor for each unit amount when the paper is transported for a predetermined distance is accumulated in the transport sensor output value recording means at least once for the predetermined distance,
Based on the accumulated output value of the sensor, determine a threshold value as the predetermined value,
Based on the threshold value and the accumulated output value of the sensor, an interval between the position on the paper where the sensor output value is equal to or greater than the threshold and the position on the paper where the sensor output value is maximum. A ratio between a first distance and a second distance that is an interval between a position on the sheet at which the sensor output is equal to or greater than the threshold and a position on the sheet at which the sensor output value is less than the threshold is calculated. And
When printing, a paper cueing position is obtained by multiplying the distance between the position on the paper where the sensor output is greater than or equal to the threshold and the position on the paper where the sensor output value is less than the threshold by the ratio. A method for controlling the cueing position of a sheet, characterized by: During printing, the distance between the position on the paper where the sensor output is greater than or equal to the threshold and the position on the paper where the sensor output value is less than the threshold, and the output value of the sensor is greater than or equal to the threshold The difference from the paper position to the paper cue position is calculated as a correction amount,
6. The paper cue position control according to claim 5, wherein a difference between a distance between the print head that performs printing on the paper and the sensor and the correction amount is a conveyance amount of the paper at the time of printing. Method. The output value of the sensor for each unit amount is accumulated in the sensor output value recording means for the conveyance of the predetermined distance twice or more,
Was calculated based on the output value of the sensor for each of said unit quantity of each round, the sheet indexing position according to claim 5 or 6, wherein the taking each average for said threshold value and said ratio for each round Control method.
  8. The paper cueing position according to claim 5, wherein the number of driving steps of the stepping motor that transports the paper is counted, and the transport amount of the paper is measured based on the counted value. Control method.   9. A paper cue position control program that causes a computer that controls the operation of the label printer to execute the paper cue position control method according to claim 5.

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