JP2024089759A - Thermal printer, energization method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent gradation deviation from occurring due to a difference in stored heat amount caused by a difference in sparseness of dots including a high gradation value.

SOLUTION: A control unit 10 of a thermal printer 1 performs a heat adjustment process for energizing, as history energization for a prescribed time, a heater element 71 assigned a gradation value 7 (largest gradation value) in a current printing field in association with the current printing field when there is a heater element 71 assigned a gradation value 0 (smallest gradation value) in the last printing field, and omitting the history energization associated with the current printing field when there is no heater element 71 assigned a gradation value 0 (smallest gradation value) in the last printing field. The control unit 10 divides a plurality of heater elements 71 into a plurality of groups (4 dots) G1-G6 for history reference, and performs the heat adjustment process for each of the groups G1-G6 for history reference.

SELECTED DRAWING: Figure 6

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a thermal printer, a power supply method, and a program.

Conventionally, thermal printers with heating elements that print characters and the like by dot output are known. With regard to this thermal printer, it has been disclosed that, in order to achieve uniform print density, the number of energizing pulses when outputting each dot is selected according to the previous energizing history state (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 8-156307

However, the technology disclosed in the above-mentioned Patent Document 1 looks at the current history of each dot individually, so there is a problem in that the amount of heat stored varies depending on the current history of surrounding dots, causing changes in print density. In particular, when gradation printing is performed, gradation deviation occurs due to changes in print density, which affects the gradation expression.

The present invention was made in consideration of these problems, and aims to prevent gradation deviations caused by differences in the amount of heat storage that occur due to differences in density of dots with high gradation values.

In order to solve the above problems, the thermal printer according to the present invention comprises:
A thermal printer has a plurality of heating elements arranged in a predetermined direction, and is capable of printing dots corresponding to each heating element in multiple gradations by controlling the duration or number of times that each heating element is energized,
When there is a heating element to which a minimum gradation value is assigned in the previous printing field, the heating element to which a maximum gradation value is assigned in the current printing field is energized for a predetermined time as a historical energization, in association with the current printing field.
If there was no heating element to which the minimum gradation value was assigned in the previous printing field, the historical energization associated with the current printing field is omitted.
A control means for executing a heat adjustment process is provided,
The control means divides the plurality of heating elements into a plurality of groups and performs the heat adjustment process for each of the groups.
It is characterized by:

The present invention makes it possible to prevent gradation deviations caused by differences in the amount of heat storage that occur due to differences in the density of dots with high gradation values.

1 is a plan view illustrating a schematic external configuration of a thermal printer according to an embodiment. FIG. 2 is a plan view showing the thermal printer shown in FIG. 1 with its cover open. FIG. 2 is a block diagram showing a control configuration of the thermal printer according to the embodiment. FIG. 4 is a diagram showing a print surface of a tape member. 11A and 11B are diagrams showing print images and current waveforms corresponding to each gradation value. 1 is a graph showing the relationship between current application time (heating temperature) and gradation value (print density). 13 is a flowchart showing a control procedure for a history data generation process. 11 is a table showing each dot scanned for a certain line (a previous line and a current line) in a history data generation process and the gradation value of each dot. FIG. 11 is a diagram illustrating an example of a method for generating history data.

The following describes an embodiment of the present invention with reference to the drawings.

Figure 1 is a plan view that shows a schematic external configuration of a thermal printer in this embodiment. Figure 2 is a plan view that shows the thermal printer shown in Figure 1 with the cover open. Figure 3 is a block diagram that shows the functional configuration of the thermal printer.

The thermal printer 1 of this embodiment is a label printer that heats a tape member 5, which is a long print medium, to print images such as characters, marks, figures, and tables to create labels. The thermal printer 1 has a function of printing in multiple black and white print densities using white (no printing on a base (background, for example, white)) and black (black on a base). The thermal printer 1 also has a function of cutting the printed tape member 5.
In the following, a thermal label printer that uses thermal paper will be described as an example, but the printing method is not particularly limited, and may be, for example, a thermal transfer method that uses an ink ribbon.

As shown in FIGS. 1 and 2, a thermal printer 1 includes a device housing 2 having a cassette housing portion 21 therein.
The cassette housing portion 21 houses a tape cassette 51. The tape cassette 51 houses the tape member 5 and an ink ribbon (not shown).
A lid 3 is provided on a portion of the device housing 2 at a position covering the cassette housing section 21. When a button 3a is pressed, a locking mechanism (not shown) of the lid 3 is released, and the lid 3 rotates upward and is opened as shown in Fig. 2. With the lid 3 in the open state, the user can insert and remove the tape cassette 51.

In this embodiment, the corners of the tape cassette 51 are provided with unevenness such as notches and recesses (not shown) at different positions depending on the type of tape member 5 stored therein, such as the tape width. A tape type detection unit (not shown) that detects the presence or absence of unevenness on the tape cassette 5 is provided in the cassette storage unit 21 at a position corresponding to the corners of the tape cassette 51, and by obtaining detection information from the tape type detection unit, the control unit 10 can determine the type of tape member 5 stored in the tape cassette 51, such as the tape width, and whether the tape cassette 51 is set in the cassette storage unit 21.

Further, within the cassette housing section 21, there is provided a printing means for printing on the tape member 5 which is a long print medium.
In this embodiment, the printing means includes a thermal head 7 (see FIG. 2, etc.) equipped with a plurality of heating elements 71. The thermal head 7 (heating elements 71) is controlled by a head drive circuit 17 (see FIG. 3) and performs printing according to print data and history data (described later).
The thermal head 7 has a line of a plurality of heating elements 71 arranged in a row in the width direction of the tape medium 5 (see FIG. 4) when the tape cassette 51 is housed in the cassette housing portion 21 .
A thermistor 72 (see FIG. 3) is embedded in the thermal head 7. The thermistor 72 measures the temperature of the thermal head 7 (heating element 71) and outputs the temperature to the control unit 10.

In addition, at a position facing the thermal head 7 across the tape member 5, a platen roller 8 is provided as a transport means for transporting the tape member 5, which is the printing medium, in a transport direction (the direction of the arrow in Figures 1 and 2) along the longitudinal direction (see Figure 4).
2, the platen roller 8 faces the thermal head 7 at a portion where the heating elements 71 are arranged. When the tape member 5 passes between the platen roller 8 and the thermal head 7, the platen roller 8 presses the tape member 5 against the thermal head 7 (heating elements 71). This allows printing to be performed.

The platen roller 8 is a transport mechanism that is rotated by a transport motor 80 (see FIG. 3 ) described below and appropriately transports the tape material 5 along the transport direction (the longitudinal direction of the tape material 5). In this embodiment, the platen roller 8, which is the transport mechanism, is configured to perform forward transport, that is, transporting the tape material 5 in a forward direction (a direction from the upstream side to the downstream side in the transport direction, the forward direction) from the thermal head 7, which is the printing means, toward an outlet 22 that discharges the tape material 5 to the outside of the device.
Furthermore, a tape core engagement shaft that engages with the tape core around which the tape member 5 in the tape cassette 51 is wound in a roll, and a take-up shaft that takes up the printed ink ribbon (neither shown) are provided within the cassette housing section 21. The take-up shaft is rotated by a drive motor (not shown) to appropriately take up the ink ribbon.

At a side of the device housing 2 (in this embodiment, the right side as shown in FIG. 1) at a position corresponding to the cassette storage section 21, an outlet 22 is formed as an outlet section through which labels separated from the tape member 5 after printing are discharged. The tape member 5 (labels) printed inside the thermal printer 1 are discharged from the outlet 22 to the outside of the device.

A full-cut mechanism 9 a and a half-cut mechanism 9 b are provided as cutting mechanisms for cutting the tape material 5 between the thermal head 7 , which is a printing means, and the discharge port 22 inside the device housing 2 .
The full-cut mechanism 9a and the half-cut mechanism 9b are both provided across the width of the tape member 5, and are cutting means for cutting the tape member 5, which is the printing medium, along the medium width direction. In this embodiment, as shown in Fig. 2 etc., the full-cut mechanism 9a is disposed downstream in the transport direction of the thermal head 7, which is the printing means, and the half-cut mechanism 9b is disposed further downstream in the transport direction than the full-cut mechanism 9a.

Although not shown in the figure, the tape member 5, which is the printing medium in this embodiment, comprises a base material having an adhesive layer (not shown), and a release layer (release paper) that is arranged to cover the adhesive layer and is peeled off from the base material when the label is used (applied).
The full-cut mechanism 9a has a cutting blade that cuts the base material of the tape member 5, which is the printing medium, together with the release layer in the width direction, and performs a so-called full-cut operation that cuts the entire thickness direction of the tape member 5. The full-cut mechanism 9a performs the cutting operation by the power of a full-cut mechanism drive motor 90a (see FIG. 3).

The half-cut mechanism 9b has a cutting blade that cuts only the base material of the tape member 5 in the width direction, and performs a so-called half-cut operation that cuts a part of the tape member 5 in the thickness direction. The half-cut mechanism 9b performs the cutting operation using the power of the half-cut mechanism drive motor 90b (see Figure 3).

The lid 3 is also formed with a window 31 so that it is possible to visually check whether or not a tape cassette 51 is housed in the thermal printer 1 even when the lid 3 is closed. The lid 3 is also provided with a display unit 4.
The display unit 4 is configured by, for example, a liquid crystal display (LCD), an organic electroluminescence display, or another flat display.
In this embodiment, various setting values input by the user and character strings and designs to be printed on the tape member 5 may be displayed on the display unit 4 so that the user can check them.

A touch panel for performing various inputs may be integrally configured on the surface of the display unit 4. In this case, the touch panel also functions as the input unit 6.

An input unit 6 is also provided on the device housing 2 .
The input unit 6 includes various keys such as character input keys, a cross key, a conversion key, and an enter key.
As mentioned above, when a touch panel is integrally provided on the surface of the display unit 4, the touch panel functions as the input unit 6, and the user can perform various input, setting, and other operations by touching the touch panel.

As described above, the thermal printer 1 includes the display unit 4, input unit 6, thermal head 7 (heating element 71), thermistor 72, platen roller 8, full-cut mechanism 9a, and half-cut mechanism 9b, as well as a control unit 10, a memory unit 11, a power supply circuit 12, a display unit drive circuit 14, a head drive circuit 17, a conveyor motor drive circuit 18, and a cutter motor drive circuit 19, as shown in FIG. 3.

The control unit 10 is a control means including a processor such as a CPU (Central Processing Unit).
The storage unit 11 also includes a ROM (Read Only Memory) and a RAM (Random Access Memory), not shown, and a FLASH (registered trademark) memory, which is a non-volatile semiconductor memory that functions as a ROM or a RAM.
The control unit 10 and the storage unit 11 constitute a computer, and the control unit 10 loads various programs stored in the ROM or the like into a working area of the RAM and executes them to comprehensively control the operation of each part of the thermal printer 1.

Specifically, the control unit 10 cooperates with a program (such as a print processing application program) to realize various functions for the thermal printer 1 to perform printing.
Each function of the control unit 10 may be realized by the control unit 10 executing a program (software), or may be realized by a dedicated module (hardware).

The memory unit 11 (for example, a flash memory serving as the memory unit 11) stores a program for printing on the tape member 5 (such as the source code of the program) and various data required for executing the program (for example, character data consisting of several types of fonts (kanji, katakana, hiragana, alphabet, etc.), data on symbols and figures, spacing between figures and characters, a specified width of margin, and various other data required for the printing operation). In addition, if there is data created by the user, the user-created data is also saved in the memory unit 11.

The power supply circuit 12 is a power supply unit that generates an output voltage from the voltage from a power supply and supplies power to each unit of the thermal printer 1 .
The power source may be an internal battery or the like, or may be an external power source connected via a cable or the like.

The display unit drive circuit 14 is a controller that controls the operation of the display unit 4, and under the control of the control unit 10, controls the driver of the display unit 4 to perform display based on the display data.
That is, the display unit drive circuit 14 receives display data output from the control unit 10, and causes the display unit 4 to display various display screens based on this display data.

The head drive circuit 17 is a head drive section that drives the thermal head 7 (heating elements 71) based on a control signal, print data, and history data (described later) supplied from the control section 10.
Data specifying characters, symbols, figures, etc. selected or input by the user via the input unit 6 for label creation is sent as print data to the head drive circuit 17 via the control unit 10 when the user issues a print command. The head drive circuit 17 controls the application or non-application of voltage to the heating elements 71 for each line (see FIG. 4) based on the print data. The head drive circuit 17 also controls the application or non-application of voltage (history application) to the heating elements 71 for each line (see FIG. 4) based on history data generated by a history data generation process (see FIG. 7) described below.
Then, the head drive circuit 17 selectively passes current through the heating elements 71 in response to the print data and history data, causing the heating elements 71 to generate heat and heat the ink ribbon. As a result, the thermal head 7 prints on the tape member 5 line by line by thermal transfer from the end of the tape member 5 (the line at the right end of the tape member 5 shown in FIG. 4) along the longitudinal direction.

The thermal printer 1 of this embodiment is designed to perform black-and-white printing (monochrome printing) in eight gradations, with gradation values ranging from 0 to 7. When performing black-and-white printing in eight gradations, the following power supply control is performed. Specifically, a predetermined pulse is input to the heating elements 71 of the thermal head 7 by the head drive circuit 17, and power is supplied (main power supply) according to the number of input pulses (pulse count). The gradation value of each dot (see Figure 4) corresponds to the number of input pulses. The more pulses input to one heating element 71, the longer the power supply time for that heating element 71.

FIG. 5 is a diagram showing print images and current waveforms corresponding to each gradation value.
5, in printing one dot D, when the gradation value is 0, no pulses are input to the heating element 71, the number of energizations (energization time) of the heating element 71 is also 0, and the print density of the printed matter is the lowest (white). When the gradation value of the dot D is 1, one pulse is input to the heating element 71, the heating element 71 is energized for the energization time corresponding to the one input pulse, and the print density of the printed matter is darker (blacker) than the print density of the printing matter with a gradation value of 0. Similarly, when the gradation value of the dot D is increased, the energization time corresponding to the number of pulses input to the heating element 71 (energization times) is also longer, and the print density of the printed matter is darker (blacker). When the gradation value of the dot D is 7, seven pulses are input to the heating element 71, the heating element 71 is energized for the energization time corresponding to the seven input pulses, and the print density of the printed matter is the darkest (blackest). In this embodiment, one dot (one dot D) is printed corresponding to one heating element 71 of the thermal head 7. In addition, in this embodiment, the energization (main energization) of the heating elements 71 corresponding to each of the gradation values 1 to 7 is performed within a main energization period allocated for the main energization within a predetermined printing cycle (3.12 ms). In addition, in this embodiment, as shown in the graph of FIG. 6 showing the relationship (thermal transfer characteristic) between the energization time (heating temperature) and the gradation value (printing density), the energization corresponding to the first input pulse (energization for changing the gradation value from 0 to 1) and the energization corresponding to the seventh input pulse (energization for changing the gradation value from 6 to 7) are set to be longer than the energization corresponding to the second to sixth input pulses. This is to ensure that the color development with a gradation value of 1 and the color development with a gradation value of 7 are performed reliably.

In addition, in printing one dot D, when the gradation value is 7, as shown in FIG. 5, there are printing without history energization and printing with history energization. History energization is performed for a predetermined time before energization (main energization) performed in response to the input of the above-mentioned pulse. Furthermore, history energization is performed for dots whose history data is set to ON based on history data generated by a history data generation process (see FIG. 7) described later, and is not performed for dots whose history data is set to OFF. In this embodiment, history energization is performed within a history energization period assigned for the history energization within a predetermined printing cycle (3.12 ms). Note that history energization may be performed within the printing cycle (3.12 ms), and may be performed, for example, after main energization, that is, the history energization period may be set after the main energization period.

Returning to the explanation of the block diagram of FIG. 3, the conveyor motor drive circuit 18 drives the conveyor motor 80 to rotate the platen roller 8 .
The conveyor motor 80 is, for example, a stepping motor, and enables accurate conveyance by being driven in steps corresponding to a pulse signal input by the conveyor motor drive circuit 18. As described above, the platen roller 8 in this embodiment can rotate in the forward direction (positive direction) in the conveyance direction, and the conveyor motor drive circuit 18 appropriately inputs a signal to the conveyor motor 80 to rotate the platen roller 8 in the forward direction.

During printing operations, the transport motor drive circuit 18 controls the drive of the transport motor 80 so that the rotational operation of the platen roller 8 (i.e., the transport operation of the tape member 5 ) is synchronized with the progressing speed of printing by the thermal head 7 .
During printing operations, a drive motor (not shown) that rotates the take-up shaft that winds up the ink ribbon also operates in synchronization with the rotation of the platen roller 8, so that the transport of the tape material 5, printing by the thermal head 7, and winding of the printed ink ribbon are all timed with high precision.

The cutter motor drive circuit 19 controls the operation of the full-cut mechanism drive motor 90a, which operates the full-cut mechanism 9a, and the half-cut mechanism drive motor 90b, which operates the half-cut mechanism 9b. This allows the tape material 5 to be fully or partially cut at an appropriate position.

Next, the operation of the thermal printer 1 of this embodiment will be described with reference to Figures 7 to 9. Figure 7 is a flowchart showing the control procedure of the history data generation process carried out during gradation printing. Figure 8 is a table showing each dot scanned for a certain line (the previous line and the current line) in the history data generation process and the gradation value of each dot. Figure 9 is a diagram showing an example of a method for generating history data.

As shown in FIG. 7, when the history data generation process is started, the control unit 10 of the thermal printer 1 first scans the print data of the line (previous line) immediately before the line (current line) for which history data is to be generated from among the print data for gradation printing, in units of 4 dots starting from the end of the line (step S1). Specifically, as shown in FIG. 4, the 4 dots belonging to each of the history reference groups G1 to G6 are scanned in the order of history reference groups G1, G2, G3, G4, G5, and G6. Here, if the line (current line) for which history data is to be generated is the first line (first line) of the print data, there is no previous line. Therefore, in such a case, it is assumed that there is a previous line in which dots with a gradation value of 0 (minimum gradation value) are lined up.

Next, the control unit 10 determines whether or not there are dots with a gradation value of 0 (minimum gradation value) in the area scanned in step S1 (history reference group; 4 dots) (step S2). Here, if the line for which history data is to be generated (the current line) is the first line of the print data as described above, step S2 handles the situation as if there were dots with a gradation value of 0 in the scanned area.

If it is determined in step S2 that there are dots with a gradation value of 0 in the area scanned in step S1 (step S2; YES), the control unit 10 sets the history data to ON only for dots with a gradation value of 7 (maximum gradation value) in the area of the current line corresponding to the scanned area (step S3). In other words, in step S3, the history data is set to OFF for dots with gradation values (gradation values 0 to 6) smaller than the gradation value 7 (maximum gradation value) in the area of the current line corresponding to the scanned area.

For example, as shown in Figures 8 and 9, if it is determined that dot D4 of dots D1 to D4 in the scanned first region (print field) R1 (history reference group G1) is a gradation value of 0 (white), i.e., that the amount of heat stored in the first region R1 is insufficient, then of the dots D11 to D14 in the current line region corresponding to the first region R1 (history reference group G1), only two dots D13 and D14 with a gradation value of 7 (maximum gradation value) are set to ON in history data. As a result, for dots D13 and D14 in the current line region with history data set to ON, printing with a gradation value of 7 (see Figure 5) with history current is performed. That is, if there is a heating element 71 to which a gradation value of 0 (minimum gradation value) is assigned in the previous first region (printing field) R1, a heat adjustment process is executed under the control of the control unit 10 to apply current to the heating element 71 to which a gradation value of 7 (maximum gradation value) is assigned in the current first region (printing field) R1 for a predetermined time as historical current application. In other words, if there is a heating element 71 to which a gradation value of 7 (maximum gradation value) is assigned in the current first region (printing field) R1 and there is a heating element 71 to which a gradation value of 0 (minimum gradation value) is assigned in the previous first region (printing field) R1, a heat adjustment process is executed under the control of the control unit 10 to apply current to the heating element 71 to which a gradation value of 7 (maximum gradation value) is assigned in the current first region (printing field) R1 for a predetermined time as historical current application.

Also, in step S2, if it is determined that there are no dots with a gradation value of 0 in the area scanned in step S1 (step S2; NO), the control unit 10 sets the history data of the area of the current line corresponding to the scanned area to OFF (step S4).

For example, as shown in FIG. 8 and FIG. 9, if it is determined that there are no dots with a gradation value of 0 (white) among the dots D5-D8 in the scanned second region (printing field) R2 (group G2 for history reference), that is, if it is determined that the amount of heat stored in the second region R2 is sufficient, the history data of the region of the current line corresponding to the second region R2 (group G2 for history reference) is set to OFF. In other words, if there is no heating element 71 assigned with a gradation value of 0 (minimum gradation value) in the previous second region (printing field) R2, a heat adjustment process is executed under the control of the control unit 10, in which the history current corresponding to the second region (printing field) R2 is omitted. In other words, if there is no heating element 71 assigned with a gradation value of 7 (maximum gradation value) in the current second region (printing field) R2, a heat adjustment process is executed under the control of the control unit 10, in which the history current corresponding to the second region (printing field) R2 is omitted.

Next, the control unit 10 determines whether scanning of one line targeting the previous line has been completed (step S5).

If it is determined in step S5 that scanning of one line targeting the previous line has not been completed (step S5; NO), the control unit 10 updates the area (4 dots) to be scanned (step S6). For example, if the area to be scanned up until that point was an area belonging to history reference group G1 (see FIG. 4), the area to be scanned is updated to an area belonging to history reference group G2 (see FIG. 4). The control unit 10 then returns the process to step S1 and repeats the subsequent processes.

Also, in step S5, if it is determined that scanning of one line targeting the previous line has been completed (step S5; YES), the control unit 10 updates the previous line to be scanned to the next line (step S7).

Next, the control unit 10 determines whether the updated previous line is the final line of the print data (step S8).

If it is determined in step S8 that the updated previous line is not the final line of the print data (step S8; NO), the control unit 10 returns the process to step S1 and repeats the subsequent processes.

Also, if it is determined in step S8 that the updated previous line is the final line of the print data (step S8; YES), the control unit 10 ends the history data generation process.

As described above, if there was a heating element 71 assigned a gradation value of 0 (minimum gradation value) in the previous printing field, the control unit 10 of the thermal printer 1 performs a heat adjustment process in which current is applied to the heating element 71 assigned a gradation value of 7 (maximum gradation value) in the current printing field for a predetermined period of time as historical current application, whereas if there was no heating element 71 assigned a gradation value of 0 (minimum gradation value) in the previous printing field, the historical current application associated with the current printing field is omitted.
Therefore, according to thermal printer 1, if there are dots with a gradation value of 0 in the previous printing field, the amount of heat stored in the heating element 71 corresponding to that printing field is determined to be low, and historical current is applied to the heating element 71 to which a gradation value of 7 is assigned in the current printing field in association with the current printing field, whereas if there are no dots with a gradation value of 0 in the previous printing field, the amount of heat stored in the heating element 71 corresponding to that printing field is determined to be high, and historical current application associated with the current printing field is omitted, thereby preventing gradation deviations caused by differences in heat storage amount that arise due to differences in density of dots with high gradation values.

Furthermore, the control unit 10 divides the plurality of heating elements 71 into a plurality of history reference groups (4 dots) G1 to G6, and executes the heat adjustment process for each of the history reference groups G1 to G6.
Therefore, according to the thermal printer 1, the density of high gradation value dots is judged for each of the multiple history reference groups G1 to G6, and the judgment can be made accurately. As a result, the heat adjustment process can be more appropriately performed for each of the multiple history reference groups G1 to G6, and the occurrence of gradation deviation due to differences in heat storage amount caused by differences in density of high gradation value dots can be further prevented.

Although the present invention has been specifically described above based on the embodiment, the present invention is not limited to the above embodiment and can be modified without departing from the gist of the present invention.
For example, in the above embodiment, in step S1 of the history data generation process (see FIG. 7), the print data of the previous line is scanned in units of 4 dots, but it may be scanned in units of 5 dots or more, or in units of 2 dots or 3 dots. In other words, the history reference group may be a group with a unit of 5 dots or more, or a group with a unit of 2 dots or 3 dots.

In addition, in the above embodiment, a thermal printer 1 that performs black-and-white printing in eight gradations, with a minimum gradation value of 0 and a maximum gradation value of 7, has been described as an example, but the printing gradation is not limited to eight gradations, and the thermal printer may perform black-and-white printing in, for example, 16 gradations (minimum gradation value 0, maximum gradation value 15) or 256 gradations (minimum gradation value 0, maximum gradation value 255).

In the above embodiment, in step S2 of the history data generation process (see FIG. 7), it is determined whether or not there are dots with a gradation value of 0 (minimum gradation value) in the scanned area (4 dots), but it may be determined whether or not there are dots with a gradation value of 1 (first gradation value) or less in the scanned area (4 dots). If it is determined in step S2 that there are dots with a gradation value of 1 (first gradation value) or less in the scanned area (step S2; YES), in step 3, for example, the history data may be set to ON only for dots with a gradation value of 6 (second gradation value) and a gradation value of 7 (a gradation value equal to or greater than the second gradation value) in the area of the current line corresponding to the scanned area, and the history data may be set to OFF for dots with gradation values of 0 to 5 (a gradation value smaller than the second gradation value). On the other hand, if it is determined in step S2 above that there are no dots with a gradation value of 1 (first gradation value) or less in the scanned area (step S2; YES), then in step 4, the history data for the area of the current line that corresponds to the scanned area may be set to OFF.

In the above embodiment, an example is disclosed in which the storage unit 11 (e.g., a flash memory, etc.) is used as a computer-readable medium for the program according to the present invention, but this is not limiting. Portable recording media such as CD-ROMs can be used as other computer-readable media. In addition, carrier waves can also be used in the present invention as a medium for providing data for the program according to the present invention via a communication line.

Although an embodiment of the present invention has been described, the scope of the present invention is not limited to the above-mentioned embodiment, but includes the scope of the invention described in the claims and its equivalents.

REFERENCE SIGNS LIST 1 Thermal printer 2 Device housing 3 Lid 4 Display unit 5 Tape member 6 Input unit 7 Thermal head 8 Platen roller 9a Full-cut mechanism 9b Half-cut mechanism 10 Control unit 11 Memory unit 12 Power supply circuit 14 Display unit drive circuit 17 Head drive circuit 18 Conveyor motor drive circuit 19 Cutter motor drive circuit 21 Cassette storage unit 22 Discharge port 31 Window unit 51 Tape cassette 71 Heating element 72 Thermistor 80 Conveyor motor 90a Full-cut mechanism drive motor 90b Half-cut mechanism drive motor

In order to solve the above problems, the thermal printer according to the present invention comprises:
A thermal printer has a plurality of heating elements arranged in a predetermined direction, and is capable of printing dots corresponding to each heating element in multiple gradations by controlling the duration or number of times that each heating element is energized,
When there is a heating element to which a minimum gradation value is assigned in the previous printing field, a heating element to which a maximum gradation value is assigned in the current printing field is energized for a predetermined time as a historical energization in the current printing field ,
If there was no heating element to which the minimum gradation value was assigned in the previous printing field, the historical energization in the current printing field is omitted.
A control means for executing a heat adjustment process is provided,
The control means divides the plurality of heating elements into a plurality of groups and performs the heat adjustment process for each of the groups.
It is characterized by:

Claims (7)

A thermal printer has a plurality of heating elements arranged in a predetermined direction, and is capable of printing dots corresponding to each heating element in multiple gradations by controlling the duration or number of times that each heating element is energized,
When there is a heating element to which a minimum gradation value is assigned in the previous printing field, the heating element to which a maximum gradation value is assigned in the current printing field is energized for a predetermined time as a historical energization, in association with the current printing field.
If there was no heating element to which the minimum gradation value was assigned in the previous printing field, the historical energization associated with the current printing field is omitted.
A control means for executing a heat adjustment process is provided,
The control means divides the plurality of heating elements into a plurality of groups and performs the heat adjustment process for each of the groups.
A thermal printer characterized by: In the heat adjustment process, the historical energization associated with the current printing field is omitted for heating elements to which a gradation value smaller than a maximum gradation value is assigned in the current printing field.
2. The thermal printer according to claim 1. A thermal printer has a plurality of heating elements arranged in a predetermined direction, and is capable of printing dots corresponding to each heating element in multiple gradations by controlling the duration or number of times that each heating element is energized,
When there is a heating element to which a gradation value equal to or less than a first gradation value is assigned in the previous printing field, a heating element to which a gradation value equal to or greater than a second gradation value that is greater than the first gradation value in the current printing field is assigned in association with the current printing field is energized for a predetermined time as historical energization,
If there was no heating element to which a gradation value equal to or less than the first gradation value was assigned in the previous printing field, the historical energization associated with the current printing field is omitted.
A control means for executing a heat adjustment process is provided,
The control means divides the plurality of heating elements into a plurality of groups and performs the heat adjustment process for each of the groups.
A thermal printer characterized by: In the heat adjustment process, the historical energization associated with the current printing field is omitted for heating elements to which a gradation value smaller than the second gradation value is assigned in the current printing field.
4. The thermal printer according to claim 3. A thermal printer has a plurality of heating elements arranged in a predetermined direction, and is capable of printing dots corresponding to each heating element in multiple gradations by controlling the duration or number of times that each heating element is energized,
When there is a heating element to which the maximum gradation value is assigned in the current printing field and there is a heating element to which the minimum gradation value is assigned in the previous printing field, the heating element to which the maximum gradation value is assigned in the current printing field is energized for a predetermined time as historical energization in association with the current printing field,
If there is no heating element to which the maximum gradation value is assigned in the current printing field, the historical energization associated with the current printing field is omitted.
A control means for executing a heat adjustment process is provided,
The control means divides the plurality of heating elements into a plurality of groups and performs the heat adjustment process for each of the groups.
A thermal printer characterized by: A method of energizing a thermal printer that has a plurality of heating elements arranged in a predetermined direction and is capable of printing dots corresponding to the heating elements in multiple gradations by controlling the energization time or the number of energization times for each of the heating elements, comprising:
When there is a heating element to which a minimum gradation value is assigned in the previous printing field, the heating element to which a maximum gradation value is assigned in the current printing field is energized for a predetermined time as a historical energization, in association with the current printing field.
If there was no heating element to which the minimum gradation value was assigned in the previous printing field, the historical energization associated with the current printing field is omitted.
Including heat treatment,
The heat adjustment process is performed for each of the groups after the plurality of heat generating elements are divided into a plurality of groups.
A method of energizing a vehicle. A computer for a thermal printer having a plurality of heating elements arranged in a predetermined direction, the computer being capable of printing dots corresponding to the heating elements in multiple gradations by controlling the energization time or the number of energization times for each of the heating elements,
When there is a heating element to which a minimum gradation value is assigned in the previous printing field, the heating element to which a maximum gradation value is assigned in the current printing field is energized for a predetermined time as a historical energization, in association with the current printing field.
If there was no heating element to which the minimum gradation value was assigned in the previous printing field, the historical energization associated with the current printing field is omitted.
Functioning as a control means for executing heat adjustment processing;
The control means divides the plurality of heating elements into a plurality of groups and performs the heat adjustment process for each of the groups.
A program characterized by:

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