JP2013203011A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printer excellent in a printing quality by performing energizing control anticipating a voltage drop of a battery due to printing when the battery is used for printing.SOLUTION: In regard to a printer wherein printing takes place on a printing medium by a printing head wherein printing pixels driven by power supply via a battery are arranged in lines, the printer includes a counting means which counts the number of dots energized in one printing line of the printing head simultaneously, a first estimating means which estimates a battery voltage drop caused by energizing the number of dots counted by the counting means for energizing a first printing line, a second estimating means which estimates a battery voltage drop caused by energizing the number of dots counted by the counting means for simultaneously energizing a second line to be printed subsequent to the first printing line, and a power determining means which determines the energizing time of the printing head for printing the second line based on the voltage drops estimated by the first estimating means and the second estimating means.

Description

  Embodiments described herein relate generally to a printer that prints by receiving power from a battery.

  In order to print on paper, a thermal head is used to heat the thermal paper to cause color development, or a printer that transfers the ink on the transfer ribbon onto the paper by the heat of the thermal head and prints is known. In addition, in order to be able to print one line in the width direction of the paper without moving the print head, there is one using a line thermal head in which the length of the thermal head is about the width of the paper. Such a line thermal head has a length of about 2 inches or 4 inches, for example, and has a pixel (heating element) of 200 to 300 dots per inch.

  By using the line thermal head, the printing speed can be increased because printing is performed over the entire width of the sheet at a time while the sheet is conveyed.

  By the way, thermal heads are often used in battery-driven printers because they are more compact than printers using other print heads. However, when energizing many pixels at once, for example, when printing a ruled line across the entire width of the paper, the number of energized pixels is very large and a heavy load is applied to the battery.

  Therefore, in order to reduce the load on the battery, printing of one line of the ruled line is divided into a plurality of energizations, but there is a step in the line when the printing result that should be one is seen. In some cases, a line may be printed, and it takes a lot of time to print one line by energizing a plurality of times, which is not suitable for high-speed printing.

  For this reason, it is desirable to print the entire ruled line with a single energization. However, when such a printing is performed, that is, when a large number of pixels are energized at once, a very large current flows. The print result may not be obtained because of a drop in the image.

  By the way, in a battery-powered printing apparatus, there is a printer that determines whether or not the next line can be printed from the data printed on the next line, and reduces the printable character size if it cannot be printed.

JP 2006-159824 A

  Even if there is a sufficient battery voltage for printing the next line, the battery voltage is reduced by printing. In addition, this phenomenon appears remarkably when energizing many pixels. If the voltage drop of the print line can be predicted and the characters can be made smaller, the energization amount can be suppressed a little. However, the energization amount can be changed when performing printing that cannot change the size like a ruled line. Absent. Also, in order to achieve the fastest possible printing speed, it takes a very short time from the end of energization of the previous print line to the energization of the print line, so the process of predicting the voltage drop after measuring the battery voltage May not be in time.

  Here, when the battery voltage drops, each pixel of the thermal head due to energization is not at a temperature sufficient for printing, and the printing result appears faint or thin.

  In this embodiment, in a printer that prints on a print medium using a dot head in which print pixels driven by power supplied from a battery are arranged in a line, energization is simultaneously performed on one print line of the dot head. Counting means for counting the number of dots, first predicting means for predicting a voltage drop of the battery that drops by energizing the number of dots counted by the counting means for energizing the first print line, and the first print line Second predicting means for predicting a voltage drop of the battery that drops by energizing the number of dots counted by the counting means energized simultaneously to the second line to be printed next, the first predicting means and the second predicting And a power deciding means for deciding the energization time of the dot head for printing the second line based on the predicted voltage drop predicted by the means. .

FIG. 2 is an electrical block diagram of the thermal printer of this embodiment. The figure which shows the area which memorize | stores the standard energization time formed in ROM provided in this thermal printer. The figure which shows the area which memorize | stores the estimated voltage which falls with temperature by the printing dot soot formed in ROM provided in this thermal printer. 6 is a flowchart showing processing executed by the thermal printer. 6 is a flowchart showing processing executed by the thermal printer. The figure which shows the specific example at the time of printing with this thermal printer. The figure which shows the ratio compared with the electricity supply time correct | amended with this thermal printer, and a supply voltage.

  Hereinafter, the label printer for printing on the label will be described with reference to FIGS. 1 to 6.

  FIG. 1 is an electric block diagram of the thermal printer of this embodiment, FIG. 2 is a diagram showing an area for storing a standard energization time formed in a ROM provided in the thermal printer, and FIG. 3 is provided in the thermal printer. FIG. 4 is a diagram showing an area for storing a predicted voltage that drops according to the number of print dots and temperature formed in the ROM, FIG. 4 is a flowchart showing processing executed by the thermal printer, and FIG. 5 is processing executed by the thermal printer. FIG. 6 is a diagram showing a specific example when printing is performed by this thermal printer, and FIG. 7 is a diagram showing a comparison of the energization time corrected by this thermal printer and the supply voltage.

  The label printer 1 prints on a label sheet in which a plurality of labels are continuously pasted on a long mount. As shown in FIG. 1, a CPU (Central Processing Unit) 2 and an area to be described later are formed. ROM (Read Only Memory) 3, display buffer and print buffer, RAM (Random Access Memory) 4 functioning as other work area, and pixels (heating resistors) for printing on labels in the width direction of the paper A thermal head 5 arranged as one line, a keyboard 6 for inputting various data, a display 7 for displaying data input from the keyboard 6, and the thermal head 5 for conveying label paper are arranged. The motor 8 and the sensor control unit 9 are connected by the bus line 10. To have. A temperature sensor 11 and a voltage sensor 12 are connected to the sensor control unit 9. The temperature sensor 11 is a sensor that detects the ambient temperature in the printer, and the voltage sensor 12 is a sensor that measures the output voltage of the battery 13.

  The ROM 3 descends after printing which varies depending on the energization time table 21 for the standard thermal head 5 shown in FIG. 2 and the number of dots energized when printing and the temperature measured by the temperature sensor 11 shown in FIG. A predicted voltage table 22 for storing the predicted voltage is provided.

  The energization time table 21 shows a standard energization time when there is no voltage drop in the battery 13. That is, when the battery 13 is fully charged, the energization time for energizing the thermal head 5 is changed according to the temperature measured by the temperature sensor 11. In this example, the energization time is shown when the ambient temperature is 0 degree, 10 degrees, 20 degrees, 30 degrees, and 40 degrees, but the measured temperature is from plus 5 degrees to minus 5 degrees of each temperature in the table. In this range, the energization time in this table may be used, or the energization time may be obtained by a predetermined calculation formula from two temperatures in the range where the measured temperature falls.

  FIG. 3 shows the output voltage of the battery 13 that drops in one line in a matrix according to the ambient temperature, the number of print dots, and the initial voltage of the battery 13. The initial voltage value is a voltage value measured before printing is started. Although the details of the process will be described later, the line drop voltage is a voltage that drops when a line is printed, and the next line drop voltage is a voltage that drops when the next line is printed. It is.

  Next, processing executed by the label printer 1 will be described. When the power is turned on, the information displayed before the current power is turned on is displayed on the display unit 7. Usually, it is print information for printing and issuing a label. Next, the label information to be printed is input. If the print format is not changed, only print data is input. If the print format changes, the print format can be changed by calling the format stored in the ROM 2 or the like.

  When a print command is input from the keyboard 6, the flowcharts shown in FIGS. 4 and 5 are executed. First, the value N of the counter provided on the RAM 4 that counts the lines to be printed is set to “0” (Act 1), the ambient temperature is detected by the temperature sensor 12 (Act 2), the initial voltage of the battery 13 is acquired (Act 3), Read the data of the Nth line (Act4). By the way, there is no data to be printed on the 0th line. When the data of the Nth line is read, the energization time corresponding to the ambient temperature is determined from the energization time area of FIG. 2 (Act 5), and the battery drop voltage predicted from the read number of energized pixels, the ambient temperature, and the battery voltage. Is calculated (Act 6). Then, the data of the next line, that is, the (N + 1) th line is read (Act 7), the voltage of the battery 13 is detected by the voltage sensor 12 (Act 8), and the energization time of the Nth line is corrected (Act 9).

  Then, the Nth line is energized to the thermal head 5 (Act 10). In the case of the 0th line, this energization process may not be performed. Then, while energizing the thermal head 5, the number of pixels energized in the Nth line and the voltage drop of the battery 13 predicted from the ambient temperature are calculated (Act 11), and the number of pixels energized in the N + 1th line are calculated. The voltage drop of the battery 13 predicted from the ambient temperature is calculated (Act 12). Then, it is determined whether or not the energization time determined in Act 9 has elapsed since the start of energization (Act 13). If it has not elapsed, the process of Act 13 is repeated until it has elapsed, and when it has elapsed, the energization is stopped ( Act 14), 1 is added to the counter N for the processing of the next line (Act 15), whether all the printing is completed, that is, whether all the print data stored in the print buffer is supplied to the thermal head. If it is determined (Act 16) and printing has not been completed, the processing from Act 7 is performed. When printing is completed, the process exits from this flowchart.

  Next, an example in which 600 pixels are continuously printed on 5 lines at an initial battery voltage of 12.3 V and an ambient temperature of 0 ° C. will be described.

  First, in order to determine the energization time of the first line, the voltage drop of the battery 13 at the 0th line is obtained. Here, in the 0th line, the voltage drop of the battery 13 does not occur from the table of FIG. Therefore, the line drop voltage in FIG. Next, since there is 600 pixel print data for the first line, it can be seen from the table in FIG. 3 that a voltage drop of 0.7 V is expected. Therefore, the next line drop voltage in FIG. 6 is 0.7. Next, the predicted voltage drop is calculated. The predicted voltage drop is expressed by the following equation.

Predicted voltage drop = measured voltage + corresponding line voltage drop + next line voltage drop
-Initial voltage When the predicted voltage drop is less than 0, it is set to 0.
Using this predicted voltage drop, the predicted voltage is calculated by the following formula.
Predicted voltage = measured voltage−predicted drop voltage This predictive voltage indicates the voltage drop of the battery 13 generated by printing the line during printing of the line and the voltage drop generated when the next line is printed. This is performed in order to predict and determine the energization time to be supplied to the next line. When the supplied battery voltage decreases, the energy supplied to each pixel decreases, so the energization time is lengthened to compensate for this.

  FIG. 6 will be described again. First, as described above, the line drop voltage is calculated from the predicted voltage table 22 of FIG. 3 as follows: first line: 0.7, second line: 0.7, third line: 0.7, fourth line: 0 .7, 5th line: 0, and the next line drop voltage is similarly 1st line: 0.7, 2nd line: 0.7, 3rd line: 0.7, 4th line: 0.7, 5th line: 0.7. The measurement voltage is a voltage measured at Act 8 in FIG. The supply voltage is the voltage actually supplied, that is, the voltage measured after printing of each line, and is the same as the measurement voltage of the next line. The predicted voltage drop and the predicted voltage are obtained by the above-described calculation formula.

  As a specific example, the first line and the fourth line in FIG. 6 will be described in more detail. In the first line, the measurement voltage is 12.3V and the supply voltage is 11.6V. Since both the line drop voltage and the next line drop voltage are 0.7V, the predicted drop voltage is 1.4V (= measurement voltage 12.3V + the line drop voltage 0.7V + the next line drop voltage 0.7V). The initial voltage is 12.3 V), and the predicted voltage is 10.9 V (= measured voltage 12.3 V-predicted voltage drop 1.4 V).

  Similarly, for the fourth line, the measurement voltage is 10.8 V, the supply voltage is 10.7 V, the line drop voltage and the next line drop voltage are both 0.7 V, and −0.1 V according to the calculation formula. In the case of a negative numerical value, it is 0 V, so the predicted voltage drop is 0. As a result, the predicted voltage becomes 10.8 V, the same as the measured voltage.

  FIG. 7 is a diagram showing the energization time obtained from the calculation formula and the ratio compared with the predicted voltage and the supply voltage when corrected by this thermal printer.

  First, since the predicted voltage is obtained as described above, the energization time can be set to an appropriate energy from a predetermined calculation formula.

Next, since the predicted voltage of the battery 13 is obtained, the applied energy can be obtained by the following calculation formula. That means
Applied energy after correction = Applied energy before correction x (Printing start voltage) ²
÷ (Predicted voltage) ²
It becomes.

  The corrected applied energy is one line ahead, that is, the applied energy of the next line. When the energy obtained from the supply voltage shown in FIG. 6 is compared with the energy obtained from the predicted voltage, the difference is 3% at the maximum. When printing is performed without predicting a voltage drop, the printing energy is almost appropriate as compared with the energy difference of about 20%. That is, by calculating the applied energy corrected one line before, it is possible to obtain the applied energy corresponding to each line and obtain an image of good quality.

  By the way, as a characteristic of the battery 13, if one line is printed when the voltage is sufficiently high at 11.4 V or higher in this embodiment, a voltage drop of 0.7 V occurs. Even if one line is printed when the voltage drops to a certain voltage, no voltage drop occurs.

  As described above, in this label printer 1, the voltage of the line next to the line being printed supplied to the thermal head 5 is set to the number of dots, the ambient temperature, the battery of the line being printed and the next line to be printed next. It is calculated from the initial voltage of 13 and the measured voltage measured immediately before printing the line. Then, by setting the energization time according to the measured voltage, the thermal head 5 can be provided with sufficient electric energy as necessary, so that printing with good print quality can be performed. In addition, since the voltage drop due to printing differs depending on the number of pixels to be printed, the predicted voltage drop of the battery 13 is changed depending on whether a large amount of current flows from the battery or a relatively small amount of current. Therefore, more appropriate electric energy can be given to the thermal head.

  The above-described table needs to be set according to the power consumption of the battery 13, the thermal head 5, the motor 8 for transporting paper, and other control units.

  In addition to the thermal head 5, any line head that can be driven by the battery 13 and whose energization amount changes according to the number of energized pixels can be applied to an ink jet printer, a dot impact printer, or the like.

  As described above, the embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and modifications can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

1. Label printer 5 Thermal head 6 Keyboard 8 Motor 11 Temperature sensor 12 Voltage sensor 13 Battery

Claims (6)

In a printer that prints on a print medium using a print head in which print pixels driven by power supplied by a battery are arranged in a line,
Counting means for counting the number of dots to be energized simultaneously in one print line of the print head;
First predicting means for predicting a voltage drop of the battery that drops by energizing the number of dots counted by the counting means energizing the first print line;
Second predicting means for predicting a drop voltage of the battery that drops by energizing the number of dots counted by the counting means energized simultaneously to a second line to be printed next to the first print line;
A printer comprising: a power determining unit that determines an energization time of the print head for printing the second line based on the predicted voltage drop predicted by the first predicting unit and the second predicting unit. Voltage measuring means for measuring a voltage for starting printing of the first print line by the print head;
2. The printer according to claim 1, wherein the power determination unit determines an energization time based on a voltage obtained by subtracting a predicted voltage drop predicted by the first prediction unit and the second prediction unit from a voltage measured by the voltage measurement unit. . Further comprising a table assuming a voltage value at which the battery drops when one line of the print head is printed with the number of dots energized simultaneously in one line;
The printer according to claim 2, wherein the first prediction unit obtains the voltage value measured by the voltage measurement unit by subtracting the corresponding voltage in the table. A temperature sensor that measures the ambient temperature;
Further comprising a table assuming a voltage value at which the battery drops when one line of the print head is printed according to the temperature measured by the temperature sensor;
The printer according to claim 2, wherein the first predicting unit obtains the voltage measured by the voltage measuring unit by subtracting a corresponding voltage in the table. The printer according to claim 2, wherein the second prediction unit obtains the voltage value predicted by the first prediction unit by subtracting the corresponding voltage in the table. The printer according to any one of claims 3 to 5, wherein the table is a table in which a voltage drop varies depending on a voltage value measured by the voltage measuring unit.

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