JP7485148B2 - Printing device, printing method, and program - Google Patents

Description

The present invention relates to a printing apparatus, a printing method, and a program.

It is known that in printing devices with thermal heads, the amount of heat applied to the print medium when power is applied varies depending on the temperature of the thermal head. Changes in the amount of heat applied to the print medium are undesirable as they can cause problems such as rubbing or bleeding of the print. Technology related to such technical issues is described, for example, in Patent Document 1.

Patent document 1 describes a method of measuring the temperature of the thermal head using a thermistor installed inside the thermal head, and comparing the measured temperature with an appropriate temperature to heat or cool the thermal head. If the temperature of the thermal head can be kept at an appropriate temperature using the technology described in patent document 1, it is possible to maintain print quality at a constant level.

Japanese Patent Application Laid-Open No. 3-256757

In the approach described above, it is important to accurately grasp the temperature of the thermal head and appropriately adjust the energy applied to the thermal head. However, it is not necessarily easy to obtain the temperature of the thermal head with a high degree of accuracy using a thermistor.

This is because the thermistor is placed at a certain distance from the heating elements to avoid the driver IC and wiring that control the heating elements. In particular, when the temperature around the thermistor is low, such as immediately after printing begins, it is difficult for the thermistor to respond quickly to temperature changes in the thermal head.

In consideration of the above-mentioned circumstances, the present invention aims to provide a printing device, printing method, and program that are capable of starting predetermined control at appropriate timing based on a temperature detected by a temperature sensor such as a thermistor arranged in close proximity to a heating element in a thermal head .

A printing device according to one aspect of the present invention comprises a thermal head in which a plurality of heating elements are arranged in a predetermined direction as a heating element row ; a transport means for moving the tape-shaped printing medium relative to the thermal head so that the tape crosses over the heating element row and so that the central position of the printing medium in the width direction passes over the center of the heating element row; a temperature sensor arranged close to either one of both ends of the heating element row; and a control means for waiting for a predetermined condition to be met before starting control based on the temperature detected by the temperature sensor when controlling the energization time or magnitude of the voltage applied to each of the plurality of heating elements, wherein the predetermined condition is that the black area ratio of the printing content for a predetermined length printed on the printing medium is greater than a predetermined threshold value, and the threshold value is set to a smaller value as the tape width of the printing medium becomes larger.

A printing method according to one aspect of the present invention is a printing method performed by a printing device that includes a thermal head in which a plurality of heating elements are arranged in a predetermined direction as a heating element row , a transport means for moving a tape-shaped printing medium relative to the thermal head so that the tape crosses over the heating element row and so that the central position of the printing medium in the width direction passes over the center of the heating element row, and a temperature sensor arranged close to either one of both ends of the heating element row, the printing method including a control process for waiting for a predetermined condition to be met before starting control based on the temperature detected by the temperature sensor when controlling the energization time or magnitude of the voltage applied to each of the plurality of heating elements, the predetermined condition being that the black area ratio of the print content for a predetermined length printed on the printing medium is greater than a predetermined threshold value, and the threshold value is set to a smaller value as the tape width of the printing medium becomes larger.

A program according to one aspect of the present invention is characterized in that it causes a computer of a printing device having a thermal head in which a plurality of heating elements are arranged in a predetermined direction as a heating element row , a transport means for moving the tape-shaped print medium relative to the thermal head so that the tape crosses over the heating element row and so that the central position of the print medium in the width direction passes over the center of the heating element row, and a temperature sensor arranged close to either one of both ends of the heating element row to function as a control means that, when controlling the energization time or magnitude of the voltage applied to each of the plurality of heating elements, waits for a predetermined condition to be met before starting control based on the temperature detected by the temperature sensor, the predetermined condition being that the black area ratio of the print content for a predetermined length printed on the print medium is greater than a predetermined threshold value, and the threshold value is set to a smaller value as the tape width of the print medium becomes larger.

According to the present invention, it is possible to start predetermined control at appropriate timing based on the temperature detected by a temperature sensor such as a thermistor arranged in the vicinity of the heating elements in the thermal head.

FIG. 1 is a perspective view of a printing device 1. 2 is a perspective view of a tape cartridge 30 housed in the printing device 1. FIG. FIG. 2 is a perspective view of a cartridge housing unit 19 of the printing device 1. FIG. 2 is a cross-sectional view of the printing device 1. FIG. 2 is a block diagram showing the hardware configuration of the printing device 1. 3 is a diagram for explaining the arrangement of a thermistor 13 provided in the thermal head 10. FIG. 4 is a flowchart showing an example of a process performed by the printing device 1. FIG. 11 is a diagram showing an example of a determination condition table. FIG. 11 is a diagram showing another example of the determination condition table. FIG. 13 is a diagram showing yet another example of the determination condition table.

[First embodiment]
1 is a perspective view of a printing device 1 according to an embodiment. The printing device 1 is a thermal printer equipped with a thermal head, and is a label printer that prints on a long print medium M. In the following, a thermal transfer type thermal printer that uses an ink ribbon will be described as an example, but the printing method is not particularly limited as long as it is a thermal printer. The printing device 1 may also be a thermal type thermal printer that uses a thermal tape.

1, the printing device 1 includes a device housing 2, an input section 3, a display section 4, a lid 5, and a cassette storage section 19. The input section 3, the display section 4, and the lid 5 are arranged on the top surface of the device housing 2. In addition, although not shown, the device housing 2 is provided with a power cord connection terminal, an external device connection terminal, a storage medium insertion port, etc.

The input unit 3 includes various keys such as input keys, a directional pad, a conversion key, and a decision key. The display unit 4 is a display device such as a liquid crystal display or an organic electroluminescence (EL) display. The display unit 4 may be provided with a touch panel unit, in which case the display unit 4 may be considered as part of the input unit 3.

The lid 5 is disposed on top of the cassette storage section 19 so that it can be opened and closed. The lid 5 is opened by pressing a button 5a. A window 5b is formed in the lid 5 so that it is possible to visually check whether or not a tape cassette 30 (see FIG. 2) is stored in the cassette storage section 19 even when the lid 5 is closed. In addition, an outlet 2a is formed on the side of the device housing 2. The print medium M that has been printed on inside the printing device 1 is discharged from the device through the outlet 2a.

Figure 2 is a perspective view of the tape cartridge 30 housed in the printing device 1. Figure 3 is a perspective view of the cartridge housing section 19 of the printing device 1. Figure 4 is a cross-sectional view of the printing device 1. The tape cartridge 30 shown in Figure 2 is detachably housed in the cartridge housing section 19 shown in Figure 3. Figure 4 shows the tape cartridge 30 housed in the cartridge housing section 19.

As shown in FIG. 2, the tape cartridge 30 has a cartridge case 31 that houses the print medium M and the ink ribbon R and that has a thermal head insertion portion 36 and an engagement portion 37 formed therein. The cartridge case 31 is provided with a tape core 32, an ink ribbon supply core 34, and an ink ribbon take-up core 35.

The print medium M is wound in a roll on a tape core 32 inside the cartridge case 31. The ink ribbon R for thermal transfer is wound in a roll on an ink ribbon supply core 34 inside the cartridge case 31 with its tip wound around an ink ribbon take-up core 35.

As shown in FIG. 3, the cartridge storage section 19 of the device housing 2 is provided with a plurality of cartridge receiving sections 20 for supporting the tape cartridge 30 at a predetermined position. The cartridge receiving sections 20 are also provided with tape width detection switches 24 for detecting the width of the tape (printing medium M) contained in the tape cartridge 30.

The tape width detection switch 24 is a switch for detecting the width of the print medium M based on the shape of the tape cartridge, and is an example of a width sensor that detects the width of the print medium M. A plurality of tape width detection switches 24 are provided in the cartridge storage section 19. A plurality of tape cartridges that store print media M with different tape widths are configured to press the plurality of tape width detection switches 24 in different combinations. As a result, the control circuit 25 (see FIG. 5), which will be described later, identifies the type of tape cartridge from the combination of pressed tape width detection switches 24, and obtains information on the width (tape width) of the print medium M.

The cartridge storage section 19 further includes a thermal head 10 that has multiple heat generating elements and prints on the print medium M, a platen roller 21 that transports the print medium M, a tape core engagement shaft 22, and an ink ribbon winding drive shaft 23. Furthermore, a thermistor 13 is embedded in the thermal head 10. The thermistor 13 is an example of a temperature sensor provided in the thermal head 10.

When the tape cartridge 30 is housed in the cartridge housing 19, as shown in FIG. 4, the engagement portion 37 on the cartridge case 31 is supported by the cartridge receiving portion 20 on the cartridge housing 19. The thermal head 10 is inserted into the thermal head insertion portion 36 formed on the cartridge case 31. The tape core engagement shaft 22 is engaged with the tape core 32 of the tape cartridge 30, and the ink ribbon take-up drive shaft 23 is engaged with the ink ribbon take-up core 35.

When a print command is input to the printing device 1, the print medium M is unwound from the tape core 32 by the rotation of the platen roller 21. At this time, the ink ribbon winding drive shaft 23 rotates in synchronization with the platen roller 21, and the ink ribbon R is unwound from the ink ribbon supply core 34 together with the print medium M. As a result, the print medium M and the ink ribbon R are transported in an overlapping state. Then, as the ink ribbon R passes between the thermal head 10 and the platen roller 21, it is heated by the thermal head 10, and the ink is transferred to the print medium M, thereby printing.

The used ink ribbon R that has passed between the thermal head 10 and the platen roller 21 is wound onto the ink ribbon take-up core 35. On the other hand, the printed medium M that has passed between the thermal head 10 and the platen roller 21 is cut by the half-cut mechanism 16 and the full-cut mechanism 17, and is discharged from the discharge port 2a.

Figure 5 is a block diagram showing the hardware configuration of the printing device 1. In addition to the configuration described above, as shown in Figure 5, the printing device 1 includes a control circuit 25, a communication interface 26, a ROM (Read Only Memory) 27, a RAM (Random Access Memory) 28, a head drive circuit 18, a conveyor motor drive circuit 11, a conveyor motor 12, a cutter motor drive circuit 14, and a cutter motor 15.

The control circuit 25 includes any processing circuit, such as a CPU (Central Processing Unit). The control circuit 25 controls each part of the printing device 1 by expanding a program stored in the ROM 27 into the RAM 28 and executing it. The control circuit 25 is an example of a control unit that controls the thermal head 10.

The communication interface 26 transmits and receives data to and from an external device, for example, by wireless communication. In this case, the communication interface 26 is a communication module including an antenna, an RF (Radio Frequency) unit, and a baseband unit, and is, for example, a Wi-Fi module, a Bluetooth (registered trademark) module, or a BLE module. The communication interface 26 may transmit and receive data to and from an external device by wired communication.

ROM 27 stores a printing program for printing on the print medium M, and various data required to execute the printing program (e.g., fonts, energization tables, judgment tables, etc.). RAM 28 is a work memory used to execute the program. Note that computer-readable recording media that store programs and data used in processing by the printing device 1 include physical (non-temporary) recording media such as ROM 27.

The thermal head 10 has multiple heating elements 10a arranged in the main scanning direction. The head drive circuit 18 energizes the heating elements 10a based on print data and control signals. The thermal head 10 heats the ink ribbon with the heating elements 10a and prints one line at a time on the print medium M by thermal transfer.

The transport motor drive circuit 11 drives the transport motor 12. The transport motor 12 is, for example, a stepping motor, and rotates the platen roller 21. The platen roller 21 rotates by the power of the transport motor 12, and transports the print medium M in the longitudinal direction of the print medium M (sub-scanning direction, transport direction).

The cutter motor drive circuit 14 drives the cutter motor 15. The full cut mechanism 17 and the half cut mechanism 16 operate by the power of the cutter motor 15 and perform a full cut or half cut on the printing medium M.

In the printing device 1 configured as described above, the control circuit 25 determines whether the temperature detected by the thermistor 13 (hereinafter referred to as the sensor temperature) can be regarded as the temperature of the thermal head 10 (hereinafter referred to as the head temperature), and if it is determined that the sensor temperature cannot be regarded as the head temperature, it adjusts the energy applied to the thermal head 10 according to the print data. As a result, even if the sensor temperature does not correctly reflect the head temperature, the energy applied to the thermal head 10 is adjusted taking into account the heat generation state of the thermal head 10 predicted based on the print data, so that a stable amount of heat can be applied to the printing medium M regardless of the head temperature. In addition, if the control circuit 25 determines that the sensor temperature can be regarded as the head temperature, it adjusts the energy applied to the thermal head 10 according to the sensor temperature. As a result, the applied energy is adjusted to an appropriate energy according to the head temperature based on the sensor temperature, so that a stable amount of heat can be applied to the printing medium M regardless of the head temperature. In the following, an example will be described in which the applied energy is adjusted by adjusting the energization time for the multiple heating elements 10a, but the method of adjusting the applied energy is not limited to adjusting the energization time. For example, the applied energy may be adjusted by adjusting the voltage applied to the thermal head 10. The energization time is the time for which a current is passed through the heating elements 10a to print one dot.

Figure 6 is a diagram for explaining the arrangement of the thermistor 13 provided in the thermal head 10. Below, with reference to Figure 6, we will explain the arrangement of the thermistor 13 and the conditions under which the sensor temperature detected by the thermistor 13 can be regarded as the head temperature.

First, the arrangement of the thermistor 13 will be described. As shown in FIG. 6, the thermal head 10 provided with the thermistor 13 is provided with a plurality of heating elements 10a and a head drive circuit 18. The thermistor 13 is arranged as close as possible to the heating elements 10a while avoiding the head drive circuit 18. For this reason, as shown in FIG. 6, it is arranged away from the center of the thermal head 10.

Next, the conditions under which the sensor temperature can be regarded as the head temperature will be described. If the sensor temperature detected by the thermistor 13 sufficiently reflects the temperature of the heating element 10a (hereinafter referred to as the heating element 10a subject to power control) that corresponds to the tape width among the multiple heating elements 10a, the sensor temperature can be regarded as the head temperature.

When considering the relationship with the tape width, the following can be seen. In the thermal head 10, the heating elements 10a that are the subject of energization control differ depending on the tape width of the print medium M. As shown in FIG. 6, when printing on a print medium M1 with a wide tape width, almost all of the heating elements 10a are subject to energization control, whereas when printing on a print medium M2 with a narrow tape width, only some of the heating elements 10a located near the center of the thermal head 10 are subject to energization control. For this reason, assuming that the heating elements 10a that are the subject of energization control are evenly energized, it can be considered that the head temperature is reflected in the sensor temperature when the tape width is wide and the distance between the heating element 10a that is the subject of energization control and the thermistor 13 is shorter than when the tape width is narrow and the distance between the heating element 10a that is the subject of energization control and thermistor 13 is longer.

The distance between the heating element 10a to be controlled and the thermistor 13 also depends on the difference between the width of the thermal head 10 and the tape width (hereinafter referred to as the width difference). Even if the tape width is the same, the ease with which the head temperature is reflected in the sensor temperature differs depending on whether the difference between the tape width and the thermal head 10 is large or small. When the width difference is small, the distance between the heating element 10a to be controlled and the thermistor 13 is shorter, so it can be considered that the head temperature is reflected in the sensor temperature more than when the width difference is large. However, in the printing device 1, the width of the thermal head 10 is constant. Therefore, in the printing device 1, the difference between the width of the thermal head 10 and the tape width is uniquely determined by the tape width and corresponds 1:1 to the tape width. Therefore, in the printing device 1 with a constant head width, the distance between the heating element 10a to be controlled and the thermistor 13 is determined by the tape width, so the ease with which the head temperature is reflected in the sensor temperature depends on the tape width.

Also, when considering the relationship with the print data, the following can be seen. Since the distance from the thermistor 13 is different, the heating elements 10a that are the subject of power supply control each have a different effect on the thermistor 13 when power is supplied. If the spatial distribution of the heating elements 10a that are actually powered is uniform, the difference in effect between the heating elements 10a can be ignored. On the other hand, if the spatial distribution of the heating elements 10a that are actually powered is biased, the sensor temperature is unlikely to be a temperature that fully reflects the temperature of the entire heating elements 10a that are the subject of power supply control, that is, the head temperature. For this reason, the more uniform the spatial distribution of the heating elements 10a that are actually powered is, the more the head temperature can be considered to be reflected in the sensor temperature. The spatial distribution of the heating elements 10a that are actually powered can be specified by the print data.

The higher the black area ratio, the more uniform the spatial distribution, and therefore the higher the black area ratio, the more the head temperature is reflected in the sensor temperature. This is because when the black area ratio is high, it is highly likely that the heating elements 10a that are actually energized are spread out over a certain amount of space. The black area ratio is the ratio of printed dots to the total dots contained in the print data. In other words, it is the ratio of printed dots to the sum of printed dots and non-printed dots.

Also, when considering the relationship with the sensor temperature, the following can be seen. When the sensor temperature rises, for example, from the temperature at the start of printing by a threshold value or more, it can be considered that the head temperature is reflected in the sensor temperature. In other words, an actual increase in the temperature detected by the thermistor 13 can be used to confirm that the heat generated by the heating element 10a has been transferred to the thermistor 13.

The control circuit 25 may also determine whether the head temperature is reflected in the sensor temperature using any combination of the tape width, print data, and sensor temperature described above.

Figure 7 is a flowchart showing an example of processing performed by the printing device 1. Figure 8 is a diagram showing an example of a judgment condition table. Below, a method for controlling the printing device 1 will be explained with reference to Figures 7 and 8.

The process shown in FIG. 7 is performed, for example, by the control circuit 25 executing a program. The printing device 1 first initializes flag F (step S1). Here, the control circuit 25 sets flag F to F=0. Flag F indicates whether the sensor temperature can be regarded as the head temperature. Flag F=0 indicates a state in which the sensor temperature cannot be regarded as the head temperature, and flag F=1 indicates a state in which the sensor temperature can be regarded as the head temperature.

The printing device 1 then acquires the tape width (step S2), and further acquires the sensor temperature (step S3). Here, the control circuit 25 acquires the width of the printing medium M housed in the tape cartridge 30 as the tape width based on the signal from the tape width detection switch 24. The control circuit 25 further acquires the temperature detected by the thermistor 13 as the sensor temperature.

Then, the printing device 1 determines whether flag F is 1 (step S4). If it determines that flag F is 1 (step S4 YES), it performs the processing of step S10 described below. On the other hand, if the printing device 1 determines that flag F is not 1 (step S4 NO), the printing device 1 determines whether the sensor temperature can be regarded as the head temperature (step S5). Here, the control circuit 25 determines whether the sensor temperature acquired in step S3 can be regarded as the head temperature of the thermal head 10.

Specifically, the control circuit 25 determines whether the sensor temperature can be regarded as the head temperature based on the print data and the tape width. More specifically, the control circuit 25 first refers to table T1 shown in FIG. 8 stored in the ROM 27, and acquires the judgment condition corresponding to the tape width acquired in step S1. Table T1 is a judgment condition table in which judgment conditions for regarding the sensor temperature as the head temperature are registered. In table T1, different black area ratios are registered as judgment conditions for each tape width. The black area ratio is calculated, for example, from the print data for the next 10 mm. Note that the reason why a higher black area ratio is registered as a judgment condition for a narrower tape width is because it is considered that the narrower the tape width, the more difficult it is for the heat generated by the heating element 10a to be transmitted to the thermistor 13.

When the judgment conditions are acquired, the control circuit 25 reads ahead the print data and judges whether the print data satisfies the acquired judgment conditions. If the control circuit 25 judges that the print data satisfies the judgment conditions, it judges that the sensor temperature can be regarded as the head temperature. On the other hand, if the control circuit 25 judges that the judgment conditions are not satisfied, it judges that the sensor temperature cannot be regarded as the head temperature.

When it is determined that the sensor temperature cannot be regarded as the head temperature (step S5 NO), the printing device 1 determines the power-on time based on the print data (step S6). Here, the control circuit 25 may, for example, calculate the black coverage rate of the print line based on the print data, and determine the power-on time based on the calculated black coverage rate. The control circuit 25 may also, for example, calculate a score based on the distribution of print dots included in the print line based on the print data, and determine the power-on time based on the calculated score. Even if the number of print dots included in the print line is the same, different scores may be calculated when the print dots are clustered and when the print dots are dispersed.

Once the energization time has been determined, the printing device 1 performs printing (step S7). Here, the control circuit 25 performs printing according to the energization time determined in step S6. That is, the control circuit 25 adjusts the energy applied to the thermal head 10 based on the energization time determined in step S6, and performs printing with the adjusted energy. The printing device 1 then determines whether printing has finished (step S8), and if it determines that printing has not finished (step S8 NO), it returns to step S3 and repeats the above-mentioned process. Therefore, at the beginning of printing, printing is performed according to the energization time determined based on the print data. On the other hand, if the printing device 1 determines that printing has finished (step S8 YES), it ends the process shown in FIG. 7.

After that, if it is determined that the sensor temperature can be regarded as the head temperature (step S5 YES), the printing device 1 updates flag F (step S9). Here, the control circuit 25 sets flag F to F=1.

When flag F is updated, the printing device 1 determines the power-on time based on the sensor temperature (step S10). Here, the control circuit 25 determines the power-on time based on the sensor temperature acquired in step S3. More specifically, the control circuit 25 refers to the power-on time table stored in the ROM 27 and acquires an adjustment coefficient corresponding to the sensor temperature acquired in step S3. The control circuit 25 then determines the power-on time to be the time calculated by multiplying the reference power-on time by the adjustment coefficient.

When the energization time is determined, the printing device 1 performs printing (step S7). Here, the control circuit 25 performs printing according to the energization time determined in step S10. That is, the control circuit 25 adjusts the energy applied to the thermal head 10 based on the energization time determined in step S10, and performs printing with the adjusted energy. The printing device 1 then determines whether printing is complete (step S8), and if it determines that printing is not complete (step S8 NO), it returns to step S3 and repeats the above-mentioned process. Since the flag F was updated to 1 in step S9, the determination is always YES in step S4 from this point on. Therefore, printing is performed according to the energization time determined based on the sensor temperature. On the other hand, if the printing device 1 determines that printing is complete (step S8 YES), it ends the process shown in FIG. 7.

As described above, in the printing device 1, the control circuit 25 determines the power supply time based on the print data until it determines that the sensor temperature can be regarded as the head temperature, and after it determines that the sensor temperature can be regarded as the head temperature, it determines the power supply time based on the sensor temperature.

According to the printing device 1, until the reliability of the sensor temperature is ensured, the power supply time is adjusted based on the temperature state of the thermal head 10 predicted by the print data. This makes it possible to suppress deterioration of print quality even in a situation where the reliability of the sensor temperature is not ensured. Furthermore, according to the printing device 1, after the reliability of the sensor temperature is ensured, the power supply time is adjusted based on the sensor temperature. This makes it possible to appropriately adjust the power supply time according to the head temperature. Therefore, it is possible to more effectively suppress deterioration of print quality. Furthermore, by judging the reliability of the sensor temperature based on the black area ratio, if the judgment conditions are met, the power supply time can be determined based on the sensor temperature immediately after printing begins.

The printing device 1 may have a table T2 shown in FIG. 9 instead of the table T1. The table T2 is similar to the table T1 in that different judgment conditions are registered for each tape width. The table T2 is different from the table T1 in that the judgment conditions for a relatively narrow tape width of 18 mm or less include not only the black area ratio but also the increase in the sensor temperature. The increase in the sensor temperature is added to the judgment conditions for a narrow tape width because it takes time for heat to start being transmitted to the thermistor 13. The printing device 1 may use the table T2 as a judgment condition table. That is, the control circuit 25 may determine whether the sensor temperature can be regarded as the head temperature based on the print data, the sensor temperature, and the tape width. According to the printing device 1, even when the table T2 is used as the judgment condition table, the energization time can be adjusted based on the sensor temperature only when the sensor temperature correctly reflects the head temperature. Therefore, the energization time can be appropriately adjusted according to the head temperature. Furthermore, by using table T2, the reliability of the sensor temperature can be determined more reliably even when there is a large difference between the width of the thermal head 10 and the width of the tape.

The printing device 1 may have a table T3 shown in FIG. 10 instead of table T2. Table T3 is similar to table T2 in that different judgment conditions are registered for each tape width. Table T3 differs from table T2 in that the judgment condition for a relatively wide tape width of 24 mm or more is an increase in the sensor temperature instead of the black area ratio. The printing device 1 may use table T3 as a judgment condition table. That is, the control circuit 25 may determine whether the sensor temperature can be regarded as the head temperature based on the print data, the sensor temperature, and the tape width. According to the printing device 1, even when table T3 is used as a judgment condition table, the power supply time can be adjusted based on the sensor temperature only when the sensor temperature correctly reflects the head temperature. Therefore, the power supply time can be appropriately adjusted according to the head temperature. Furthermore, by using table T3, when the difference between the width of the thermal head 10 and the tape width is small, the pre-reading of the print data performed to calculate the black area ratio can be avoided.

The above-described embodiment is a specific example shown to facilitate understanding of the invention, and the present invention is not limited to the above-described embodiment. The printing device, control method, and program can be modified and changed in various ways without departing from the scope of the claims.

For example, in the above embodiment, an example was shown in which the control circuit 25 determines whether the sensor temperature can be regarded as the head temperature based on the print data, the sensor temperature, and the tape width, but the control circuit 25 may make the determination based on at least one of the print data and the sensor temperature. For example, the determination condition may be that the print data satisfies a predetermined condition regardless of the tape width. Also, the determination condition may be that the sensor temperature satisfies a predetermined condition regardless of the tape width. The control circuit 25 may determine whether the sensor temperature can be regarded as the head temperature based on at least one of the print data, the sensor temperature, and the tape width. The tape width itself may be the determination condition, and for example, the sensor temperature may be trusted if the tape width is equal to or greater than a predetermined width. This determination method also allows the power supply time to be appropriately adjusted according to the temperature of the thermal head.

In the above embodiment, an example was shown in which the control circuit 25 determines whether the sensor temperature can be regarded as the head temperature based on the print data, the sensor temperature, and the tape width, but the control circuit 25 may make the determination taking into account other factors. For example, the type of print medium (e.g., paper, cloth, magnet, etc.) may be taken into account.

In the above embodiment, an example was shown in which once the control circuit 25 determines that the sensor temperature can be regarded as the head temperature, the power supply time is determined on the assumption that the sensor temperature can always be regarded as the head temperature thereafter, but this is not limited to the example. For example, even after once it is determined that the sensor temperature can be regarded as the head temperature, the determination process may be repeated, and as a result, a state transition from a state in which the sensor temperature can be regarded as the head temperature to a state in which the sensor temperature cannot be regarded as the head temperature may be permitted.

In the above-described embodiment, the black area ratio was used as an example of a judgment based on print data, but the judgment method is not limited to treating all print dots equally, as in the case of the black area ratio. For example, a weighted black area ratio may be calculated by weighting according to the position of the print dot. For example, the black area ratio may be calculated by weighting according to the distance between the thermistor 13 and the print dot, and a judgment may be made based on the weighted black area ratio.

The invention as described in the claims of the present application as originally filed is set forth below.
[Appendix 1]
A thermal head having a plurality of heating elements for printing on a print medium;
a temperature sensor that detects the temperature of the thermal head as a sensor temperature;
A control unit for controlling the thermal head,
The control unit is
determining whether the sensor temperature detected by the temperature sensor can be regarded as the head temperature of the thermal head;
a temperature sensor that detects a temperature of the thermal head based on the detected temperature and a temperature of the thermal head based on the detected temperature;
[Appendix 2]
2. The printing device according to claim 1,
The control unit is
when it is determined that the sensor temperature cannot be regarded as the head temperature, a power supply time for supplying power to the plurality of heating elements is determined based on the print data;
A printing apparatus comprising: a printer that adjusts energy applied to the thermal head based on the determined energization time.
[Appendix 3]
3. The printing device according to claim 2,
The control unit is
Calculating a black coverage rate of a print line based on the print data;
A printing device comprising: a printer that determines a power supply time for powering the plurality of heating elements based on the calculated black area ratio.
[Appendix 4]
In the printing device according to any one of claims 1 to 3,
The printing apparatus, wherein the control unit adjusts energy applied to the thermal head in accordance with the sensor temperature when it is determined that the sensor temperature can be regarded as the head temperature.
[Appendix 5]
5. The printing device according to claim 4,
The control unit is
determining a time for energizing the plurality of heating elements based on the sensor temperature when it is determined that the sensor temperature can be regarded as the head temperature;
A printing apparatus comprising: a printer that adjusts energy applied to the thermal head based on the determined energization time.
[Appendix 6]
In the printing device according to any one of claims 1 to 5,
The printing apparatus, wherein the control unit determines whether or not the sensor temperature can be regarded as the head temperature based on at least one of the print data and the sensor temperature.
[Appendix 7]
The printing device according to any one of claims 1 to 5, further comprising:
a width sensor for detecting a width of the printing medium;
The printing apparatus, wherein the control unit determines whether or not the sensor temperature can be regarded as the head temperature based on at least one of the print data, the sensor temperature, and the width detected by the width sensor.
[Appendix 8]
8. The printing device according to claim 1,
The control unit is
2. A printing apparatus comprising: a printing device which determines whether or not the sensor temperature can be regarded as the head temperature until it is determined that the sensor temperature can be regarded as the head temperature.
[Appendix 9]
A method for controlling a printing device having a thermal head that prints on a print medium, comprising the steps of:
determining whether or not a sensor temperature detected by a temperature sensor for detecting the temperature of the thermal head can be regarded as a head temperature of the thermal head;
a control method for controlling a temperature of the thermal head that is changed depending on a print data when the sensor temperature is determined to be unable to be regarded as the head temperature;
[Appendix 10]
A printing device having a thermal head for printing on a print medium,
determining whether or not a sensor temperature detected by a temperature sensor for detecting the temperature of the thermal head can be regarded as a head temperature of the thermal head;
a program for executing a process for adjusting energy applied to the thermal head in accordance with print data when it is determined that the sensor temperature cannot be regarded as the head temperature;

REFERENCE SIGNS LIST 1 Printing device 2 Device housing 2a Discharge port 3 Input section 4 Display section 10 Thermal head 10a Heating element 13 Thermistor 18 Head driving circuit 21 Platen roller 25 Control circuit 26 Communication IF
27 ROM
28 RAM
M, M1, M2: Printing medium R: Ink ribbon T1-T3: Table

Claims (4)

a thermal head in which a plurality of heating elements are arranged in a predetermined direction as a heating element row ;
a conveying means for moving the print medium relative to the thermal head so that the tape-shaped print medium crosses over the row of heating elements and so that the center position in the width direction of the print medium passes over the center of the row of heating elements;
a temperature sensor disposed adjacent to one of both ends of the heating element array ;
a control means for starting control based on the temperature detected by the temperature sensor after a predetermined condition is satisfied when controlling a duration or magnitude of a voltage applied to each of the plurality of heating elements;
Equipped with
the predetermined condition being that a black area ratio of a predetermined length of print content printed on the print medium is greater than a predetermined threshold;
The threshold value is set to a smaller value as the tape width of the print medium increases.
A printing device comprising: The temperature sensor is disposed at a position offset from the arrangement direction of the plurality of heat generating elements.
2. The printing device according to claim 1 . a thermal head in which a plurality of heating elements are arranged in a predetermined direction as a heating element row;
a conveying means for moving the print medium relative to the thermal head so that the tape-shaped print medium crosses over the row of heating elements and so that the center position in the width direction of the print medium passes over the center of the row of heating elements;
a temperature sensor disposed adjacent to one of both ends of the heating element array;
A printing method executed by a printing device comprising:
a control process for starting control based on the temperature detected by the temperature sensor after a predetermined condition is satisfied when controlling a duration or magnitude of a voltage applied to each of the plurality of heating elements;
the predetermined condition being that a black area ratio of a predetermined length of print content printed on the print medium is greater than a predetermined threshold;
The threshold value is set to a smaller value as the tape width of the print medium increases.
A printing method comprising: a thermal head in which a plurality of heating elements are arranged in a predetermined direction as a heating element row;
a conveying means for moving the print medium relative to the thermal head so that the tape-shaped print medium crosses over the row of heating elements and so that the center position in the width direction of the print medium passes over the center of the row of heating elements;
a temperature sensor disposed adjacent to one of both ends of the heating element array;
A computer of a printing device comprising:
a control unit that starts control based on the temperature detected by the temperature sensor after a predetermined condition is satisfied when controlling the duration or magnitude of the voltage applied to each of the plurality of heating elements;
the predetermined condition being that a black area ratio of a predetermined length of print content printed on the print medium is greater than a predetermined threshold;
The threshold value is set to a smaller value as the tape width of the print medium increases.
A program characterized by:

Images