JP2024135756A - Printing device, printing device control method, and program - Google Patents

Abstract

[Problem] To prevent deterioration of print quality due to deterioration of the print head. [Solution] A printing device 1 includes a thermal head 10, which is a print head that prints on a print medium, a thermistor 13, which is a detection unit that detects the temperature of the thermal head 10, and a control unit 5 that controls the supply of electricity to the thermal head 10 according to the deterioration state of the thermal head 10 estimated based on a comparison between the estimated temperature of the thermal head 10 and the temperature detected by the thermistor 13. [Selected Figure] Figure 5

Description

The disclosure of this specification relates to a printing device, a control method for a printing device, and a program.

Printing devices that print on a print medium by controlling the power supply to heating elements in a thermal head are known. Such a printing device is described in, for example, Patent Document 1.

Patent document 1 describes a printing device that halts ongoing printing when the temperature of the thermal head becomes higher than the upper limit temperature. With the printing device described in patent document 1, printing is not performed when the temperature of the thermal head is higher than the upper limit temperature, so it is possible to prevent printing from continuing in a state where the desired print quality cannot be obtained.

JP 2004-25512 A

However, a decrease in print quality can occur not only when the print head temperature exceeds the upper limit temperature, but also when the print head deteriorates, for example, due to fluctuations in resistance value.

In light of the above-mentioned circumstances, an object of one aspect of the present invention is to provide a technology that avoids deterioration of print quality due to deterioration of the print head.

A printing device according to one aspect of the present invention includes a print head that prints on a print medium, a detection unit that detects the temperature of the print head, and a control unit that controls the supply of electricity to the print head according to the deterioration state of the print head estimated based on a comparison between the estimated temperature of the print head and the temperature detected by the detection unit.

A control method according to one aspect of the present invention is a control method for a printing device, and includes a step of detecting the temperature of a print head that prints on a print medium, and a step of controlling the supply of electricity to the print head according to a deterioration state of the print head estimated based on a comparison between the estimated temperature of the print head and the detected temperature.

A program according to one aspect of the present invention causes a computer to detect the temperature of a print head that prints on a print medium, and to execute a process of controlling the supply of electricity to the print head according to the deterioration state of the print head estimated based on a comparison between the estimated temperature of the print head and the detected temperature.

The above aspect makes it possible to avoid deterioration of print quality due to deterioration of the print head.

1 is a perspective view of a printing apparatus according to an embodiment; 1 is a perspective view of a tape cassette stored in a printing device according to an embodiment; FIG. 2 is a perspective view of a cassette storage unit of a printing device according to an embodiment. 1 is a cross-sectional view of a printing apparatus according to an embodiment. FIG. 2 is a control block diagram of a printing apparatus according to an embodiment. 5A and 5B are diagrams illustrating a control process performed by a printing device according to an embodiment. 10 is a flowchart illustrating an example of a control process performed by a printing device according to an embodiment. FIG. 13 is a diagram showing an example of the configuration of a table for estimating a thermal head temperature. 10 is a flowchart illustrating another example of a control process performed by a printing device according to an embodiment. 10 is a flowchart illustrating yet another example of the control process performed by the printing device according to an embodiment.

An embodiment of the present invention will be described with reference to the drawings. Below, an embodiment of the present invention will be described using as an example a printing device that can print characters, images, etc. on a printing medium, such as tape, and cut the printed tape (label) and discharge it outside the device.

In this specification, tape refers to a thin, strip-shaped print medium made of plastic, paper, or any other material. Tape typically has an adhesive layer and is stickable. However, tape does not have to have an adhesive layer. A label refers to tape that is used as a print medium and has some information printed on it.

The printing device according to the embodiment described below is a label printer that prints on tape, but the print medium on which the printing device prints is not limited to tape, and the printing device is not limited to a label printer. Also, the printing device according to the embodiment described below is a printing device equipped with a thermal head, i.e. a thermal printer, but the print head of the printing device is not limited to a thermal head, and the printing device is not limited to a thermal printer. The printing device may be, for example, a thermal printer printing device using any printing method (for example, thermal transfer method, thermal method).

Figure 1 is a perspective view of a printing device 1 according to one embodiment of the present invention. The printing device 1 is a printing device equipped with a thermal head that prints on a print medium, for example, a label printer that prints on a print medium M. In the following, a thermal transfer label printer that uses an ink ribbon will be described as an example, but as mentioned above, the printing method of the printing device 1 is not particularly limited. For example, it may be a thermal method that uses thermal paper.

The printing medium M is, for example, a tape having a substrate with an adhesive layer and a release paper removably attached to the substrate so as to cover the adhesive layer. The printing medium M may also be a tape without a release paper.

1, the printing device 1 comprises a device housing 2, an input section 3, a display section 4, an opening/closing cover 18, and a cassette storage section 19. The input section 3, the display section 4, and the opening/closing cover 18 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 has various keys such as input keys, a directional pad, a conversion key, and a decision key. The display unit 4 is, for example, a liquid crystal display panel, and displays characters corresponding to inputs from the input unit 3, selection menus for various settings, messages related to various processes, and the like. 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 opening/closing lid 18 is disposed on top of the cassette storage section 19 so that it can be opened and closed. The opening/closing lid 18 opens when a button 18a is pressed. A window 18b is formed in the opening/closing lid 18 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 opening/closing lid 18 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 cassette 30 stored in the printing device 1. Figure 3 is a perspective view of the cassette storage section 19 of the printing device 1. Figure 4 is a cross-sectional view of the printing device 1. The tape cassette 30 shown in Figure 2 is detachably stored in the cassette storage section 19 shown in Figure 3. Figure 4 shows the tape cassette 30 stored in the cassette storage section 19.

As shown in FIG. 2, the tape cassette 30 has a cassette case 31 in which a thermal head insertion portion 36 and an engagement portion 37 are formed, and which contains the print medium M and the ink ribbon R. The cassette 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 the tape core 32 inside the cassette case 31. The ink ribbon R for thermal transfer is wound in a roll on the ink ribbon supply core 34 inside the cassette case 31, with its tip wound around the ink ribbon take-up core 35.

As shown in FIG. 3, the cassette storage section 19 of the device housing 2 is provided with a plurality of cassette receiving sections 20 for supporting the tape cassette 30 in a predetermined position. The cassette 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 cassette 30. The tape width detection switches 24 detect the width of the printing medium M based on the shape of the cassette.

The cassette storage section 19 further includes a thermal head 10 having multiple heating elements that print 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 measures the temperature of the thermal head 10.

When the tape cassette 30 is stored in the cassette storage section 19, as shown in FIG. 4, the engagement section 37 on the cassette case 31 is supported by the cassette receiving section 20 on the cassette storage section 19, and the thermal head 10 is inserted into the thermal head insertion section 36 formed on the cassette case 31. The tape core engagement shaft 22 is engaged with the tape core 32 of the tape cassette 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 control block diagram of the printing device 1. In addition to the above-mentioned input unit 3, display unit 4, thermal head 10, thermistor 13, half-cut mechanism 16, full-cut mechanism 17, platen roller 21, and tape width detection switch 24, the printing device 1 includes a control unit 5, a ROM (Read Only Memory) 6, a RAM (Random Access Memory) 7, a display unit drive circuit 8, a head drive circuit 9, a transport motor drive circuit 11, a stepping motor 12, a cutter motor drive circuit 14, and a cutter motor 15. The control unit 5, ROM 6, and RAM 7 constitute the computer of the printing device 1.

The control unit 5 includes a processor 5a, such as a CPU (Central Processing Unit). The control unit 5 loads a program stored in the ROM 6 into the RAM 7 and executes it, thereby controlling each part of the printing device 1, including the thermal head 10.

The ROM 6 stores a print control program for printing on the print medium M, and various data (e.g., fonts, etc.) required to execute the print control program. The ROM 6 also stores, for example, a table (see FIG. 8) described below that is used to estimate the temperature of the thermal head 10.

RAM7 functions as an input data memory that stores characters, symbols, etc. to be printed. RAM7 also functions as a print data memory that stores data (hereinafter referred to as print data) that indicates the print pattern to be formed on the print medium, which is generated based on the information stored in the input data memory. RAM7 also functions as a display data memory that stores display data to be displayed on the display unit 4.

The display unit drive circuit 8 controls the display unit 4 based on the display data stored in the RAM 7. Under the control of the display unit drive circuit 8, the display unit 4 may display the print contents in a manner that allows the progress of the printing process to be recognized, for example.

The head drive circuit 9 energizes the multiple heating elements 10a based on the print data and strobe signal supplied from the control unit 5. In particular, while the strobe signal is ON, it controls the supply of current (energization) to the heating elements 10a according to the print data. More specifically, when the strobe signal is ON and the print data indicates a print dot, it supplies current to the heating element 10a that corresponds to the print dot.

The thermal head 10 is a print head that prints on the print medium M. The thermal head 10 has multiple heating elements 10a aligned in a row in the main scanning direction. When the strobe signal sent from the control unit 5 is ON, the head drive circuit 9 selectively energizes the heating elements 10a in accordance with the print data, causing the heating elements 10a to heat the ink ribbon R and print one line at a time on the print medium M by thermal transfer. The thermistor 13 is a detection unit that detects the temperature of the thermal head 10.

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

The cutter motor drive circuit 14 drives the cutter motor 15. The half-cut mechanism 16 and full-cut mechanism 17 operate by the power of the cutter motor 15 and perform half-cutting or full-cutting of the print medium M. A full-cut is an operation in which the base material of the print medium M is cut along the width direction together with the release paper. A half-cut may be an operation in which only the base material is cut along the width direction, or an operation in which the print medium M is cut so as to create a perforation.

Figure 6 is a diagram explaining the control process performed by the printing device 1. In the printing device 1 configured as described above, the control unit 5 (processor 5a) performs the control process shown in Figure 6 in order to avoid a decrease in the print quality of the printed matter (label) due to deterioration of the thermal head 10.

First, the control unit 5 detects the temperature of the thermal head 10 that prints on the print medium M (step S1). Here, the temperature of the thermal head 10 is detected by acquiring the temperature of the thermal head 10 detected by the thermistor 13.

Then, the control unit 5 estimates the deterioration state of the thermal head 10 based on a comparison between the detected temperature and the estimated temperature of the thermal head 10 (step S2). Furthermore, the control unit 5 controls the supply of electricity to the thermal head 10 according to the estimated deterioration state (step S3).

In this way, by controlling the power supply according to the estimated deterioration state, the printing device 1 can avoid a decrease in print quality due to deterioration of the thermal head 10. In the printing device 1, the deterioration state is estimated by utilizing the fact that when the thermal head 10 deteriorates, the resistance value of the thermal head 10 fluctuates, and as a result, the power and amount of energy consumed by the thermal head 10 change. More specifically, the deterioration state is estimated from the difference between the estimated temperature and the actual temperature of the thermal head 10, which occurs due to changes in power consumption and amount of energy. Therefore, the printing device 1 only needs to be equipped with a detection unit (thermistor 13) that detects the temperature of the thermal head 10, and can estimate the deterioration state without providing a special configuration for deterioration detection.

The power supply control performed by the control unit 5 may be any method that adjusts the temperature (heat generation) of the thermal head 10 by adjusting the power consumption and the amount of energy, and the specific method is not particularly limited. For example, the temperature may be adjusted by controlling the power supply time, or the temperature may be adjusted by controlling the applied voltage.

In general, the resistance value of the thermal head 10 increases due to deterioration. When the resistance value increases due to deterioration, the temperature of the thermal head 10 does not rise to the temperature assumed at the time of design, so it is desirable for the control unit 5 to increase at least one of the voltage applied to the thermal head 10 and the power-on time. In other words, the thermal energy per line (dot) applied to the print medium may be adjusted by increasing the applied voltage to increase the energy consumed (i.e., power) per unit time, or the thermal energy per line (dot) may be adjusted by increasing the power-on time. This makes it possible to avoid a shortage of energy supply that may occur due to deterioration.

In addition, when the resistance value decreases due to deterioration, the temperature of the thermal head 10 rises above the temperature assumed at the time of design, so it is desirable for the control unit 5 to reduce at least one of the voltage applied to the thermal head 10 and the power supply time. This makes it possible to avoid excessive energy supply that may occur due to deterioration.

In addition, it is desirable to determine the amount of adjustment of the applied voltage and the energization time according to the fluctuation range of the resistance value. For example, if the resistance value increases, the energization time and the applied voltage may be increased from a reference value (initial value) at a constant rate relative to the fluctuation range of the resistance value. Also, one or more thresholds may be set for the fluctuation range of the resistance value, and the energization time and the applied voltage may be increased stepwise across the threshold. In either case, it is sufficient that the energization time and the applied voltage are adjusted so that they increase as the fluctuation range increases. In the case of a decrease in the resistance value, the energization time and the applied voltage may be decreased from a reference value (initial value) at a constant rate relative to the fluctuation range of the resistance value. Also, one or more thresholds may be set for the fluctuation range of the resistance value, and the energization time and the applied voltage may be decreased stepwise across the threshold. In either case, it is sufficient that the energization time and the applied voltage are adjusted so that they decrease as the fluctuation range increases.

The following describes a specific example of the control process performed by the printing device 1. Figure 7 is a flowchart showing an example of the control process performed by the printing device 1. Figure 8 is a diagram showing an example of the configuration of a table for estimating the thermal head temperature.

When the power is turned on and the control process shown in FIG. 7 is started by the control unit 5, the printing device 1 first detects the ambient temperature (step S101). The ambient temperature may be detected by a temperature sensor provided in the printing device 1, or may be detected by the printing device 1 communicating with an external device to obtain the ambient temperature.

When a print command is input to the printing device 1 (step S102 YES), the control unit 5 detects the temperature of the thermal head 10 before printing (step S103), then performs printing (step S104), and detects the temperature of the thermal head 10 after printing is completed (step S105).

In steps S103 and S105, the thermistor 13 detects the temperature of the thermal head 10, and the control unit 5 acquires the temperature detected by the thermistor 13 to detect the temperature of the thermal head 10. In step S104, the control unit 5 controls various circuits (head drive circuit 9, transport motor drive circuit 11, etc.) to perform power supply control, transport control, etc., to print on the print medium M. In this way, in the printing device 1, the temperature of the thermal head 10 before and after printing is detected.

Furthermore, the control unit 5 estimates the temperature of the thermal head 10 (step S106). The estimation process performed in step S106 may be performed at the start of printing or during printing.

The method of estimating the temperature is not particularly limited, but the control unit 5 may estimate the temperature of the thermal head 10 using information about temperature changes that occur in the thermal head 10 under various printing conditions, which information has been created in advance by conducting experiments, for example, as shown in FIG. 8.

The temperature is estimated based on the following (1) and (2), and the estimated temperature is the temperature when it is assumed that the thermal head 10 is not deteriorated.
(1) The detected or acquired environmental temperature information is correct.
(2) The temperature detection result by the thermistor 13 is correct, that is, the thermistor 13 is operating normally.

In addition, FIG. 8 shows that tables (table 101, table 102, table 103) are provided for each environmental temperature, recording the temperature change of the thermal head 10 according to the print data (in this example, a combination of black area rate and print length).

The control unit 5 may, for example, obtain information on the temperature change that occurs until the end of printing based on the print data from a table selected based on the environmental temperature detected in step S101, and estimate the temperature of the thermal head 10 by adding that temperature change to the temperature of the thermal head 10 detected in step S103.

Then, the control unit 5 compares the actual temperature detected in step S105 with the temperature estimated in step S106 (step S107), and adjusts the parameters related to the power supply control based on the comparison result (step S108).

In step S107, the control unit 5 compares the actual temperature with the estimated temperature, and estimates the deterioration state of the thermal head 10 based on the temperature difference. More specifically, the control unit 5 determines that the greater the deviation between the actual temperature and the estimated temperature, the more deteriorated the thermal head 10 is.

In step 108, the control unit 5 adjusts the parameters related to the power supply control according to the estimated deterioration state of the thermal head 10. Specifically, the control unit 5 sets the power supply time parameter to a time length according to the deterioration state, for example. More specifically, if the resistance value increases due to deterioration, the control unit 5 can set the power supply time longer as the deterioration state progresses, and if the resistance value decreases due to deterioration, the control unit 5 can set the power supply time shorter as the deterioration state progresses.

When the printing device 1 performs the control process shown in FIG. 7, the control unit 5 estimates the deterioration state of the thermal head 10 based on the temperature change of the thermal head 10 caused by printing, and adjusts the parameters of the power supply control according to the estimated deterioration state. This controls the power supply to the thermal head 10 in the next printing process. In other words, the control unit 5 controls the power supply to the thermal head 10 in the next printing process according to the deterioration state estimated in a certain printing process.

Therefore, according to the printing device 1, by performing the control process shown in FIG. 7, parameters are adjusted for each print, so that it is possible to prevent the print quality from changing during printing while avoiding a decrease in print quality due to deterioration of the thermal head 10.

Figure 9 is a flowchart showing another example of the control process performed by the printing device 1. The process from step S201 to step S207 of the control process shown in Figure 9 is similar to the process from step S101 to step S107 of the control process shown in Figure 7.

In the control process shown in FIG. 9, the control unit 5 determines whether the deterioration state estimated based on the comparison result of step S207 is within an acceptable range (step S208). Here, the control unit 5 may determine whether the deterioration state is within an acceptable range, for example, based on whether the temperature difference obtained by the comparison is within a predetermined range. Note that the acceptable range is, for example, a range in which the decrease in print quality due to deterioration of the thermal head 10 can be compensated for by current control.

Then, if the deterioration state of the thermal head 10 is within the acceptable range, the control unit 5 adjusts the parameters related to the power supply control according to the deterioration state (step S209). This controls the power supply to the thermal head 10 in the next printing. On the other hand, if the deterioration state of the thermal head 10 is outside the acceptable range, the control unit 5 notifies the deterioration of the thermal head 10 (step S210).

When the printing device 1 performs the control process shown in FIG. 9, the control unit 5 adjusts the current parameters to control the current to the thermal head 10 for the next print job if the current control can prevent a decrease in print quality. If the current control cannot prevent a decrease in print quality, the control unit 5 notifies the user of the deterioration of the thermal head 10 and prompts the user to replace or repair the thermal head 10.

According to the printing device 1, by performing the control process shown in FIG. 9, degradation of print quality can be avoided by power control, while allowing the user to understand deterioration of the thermal head 10 that cannot be adjusted by power control. Therefore, it is possible to more reliably prevent the creation of printed matter with low print quality.

Figure 10 is a flowchart showing yet another example of the control process performed by the printing device 1. The control process shown in Figure 10 differs from the control process shown in Figure 9 in that the control unit 5 detects the temperature of the thermal head for each predetermined number of lines after printing starts (step S303).

By the printing device 1 performing the control process shown in FIG. 10, the control unit 5 can obtain not only the temperature difference between the start and end of printing, but also information about the progression of temperature changes during printing. Therefore, it is possible to determine whether the difference between the estimated temperature and the actual temperature is a continuous one caused by deterioration of the thermal head 10, or whether it is a temporary one caused by, for example, the print data.

Therefore, according to the printing device 1, by performing the printing control shown in FIG. 10, it is possible to accurately identify the deterioration of the thermal head 10 and avoid a decrease in print quality due to the deterioration of the thermal head 10.

The above-mentioned embodiments are illustrative examples to facilitate understanding of the invention, and the present invention is not limited to these embodiments. It should be understood that the present invention includes various modifications and alternative forms of the above-mentioned embodiments. For example, it will be understood that each embodiment can be embodied by modifying the components without departing from the spirit and scope of the embodiment. It will also be understood that various embodiments can be implemented by appropriately combining the multiple components disclosed in the above-mentioned embodiments. Furthermore, it will be understood by those skilled in the art that various embodiments can be implemented by deleting some components from all the components shown in the embodiment, or by adding some components to the components shown in the embodiment. In other words, the printing device, the control method for the printing device, and the program can be modified and changed in various ways without departing from the scope of the claims.

In the above-described embodiment, the deterioration of the thermal head 10 estimated by the control unit 5 has been described assuming that it is mainly deterioration over time, but the deterioration that occurs in the thermal head 10 is not due to deterioration over time but occurs due to various causes. The deterioration estimated by the control unit 5 may include deterioration due to such deterioration over time, and may be, for example, deterioration of the thermal head 10 when it breaks down due to an external impact or the like. The control unit 5 may also estimate that the thermal head 10 has deteriorated in cases where the thermal head 10 does not generate heat due to a broken wire.

In the above embodiment, an example was shown in which a table used to estimate the temperature of the thermal head 10 was provided for each environmental temperature, but a table may be provided taking into account conditions other than the environmental temperature. For example, a table may also be provided for each tape width and the material of the printing medium.

In this specification, the expression "based on A" does not mean "based only on A" but means "based on at least A." In other words, "based on A" may also mean based on B in addition to A.

1 Printing device 5 Control unit 5a Processor 9 Head driving circuit 10 Thermal head 10a Heating element 13 Thermistor 101, 102, 103 Table M Printing medium

Claims (8)

A print head that prints on a print medium;
A detection unit that detects the temperature of the print head;
a control unit that controls the supply of power to the print head in accordance with a deterioration state of the print head estimated based on a comparison between the estimated temperature of the print head and the temperature detected by the detection unit. 2. The printing device according to claim 1,
The control unit is
When the deterioration state is within an allowable range, power supply to the print head is controlled;
A printing device which notifies the deterioration of the print head when the deterioration state is outside an allowable range. 3. The printing device according to claim 1,
The printing device according to claim 1, wherein the control unit adjusts at least one of a voltage applied to the print head and a power supply time as the deterioration state becomes worse. 3. The printing device according to claim 1,
A printing device characterized in that the control unit calculates the estimated temperature based on information created in advance by conducting experiments, the information being about temperature changes that occur in the print head depending on printing conditions. 3. The printing device according to claim 1,
The control unit calculates, as the deterioration state, a temperature difference between the estimated temperature and the temperature detected by the detection unit. 3. The printing device according to claim 1,
The printing device, wherein the control unit controls power supply to the print head in a next printing process in accordance with the deterioration state estimated in a certain printing process. A method for controlling a printing device, comprising:
Detecting the temperature of a print head that prints on a print medium;
and controlling power supply to the print head in accordance with a deterioration state of the print head estimated based on a comparison between the estimated temperature of the print head and the detected temperature. On the computer,
Detecting the temperature of a print head that prints on a print medium;
A program that executes a process of controlling the supply of power to the print head in accordance with a deterioration state of the print head estimated based on a comparison between the estimated temperature of the print head and the detected temperature.

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