JP4442282B2 - Thermal printer - Google Patents

Description

  The present invention relates to heat storage control of a thermal printer.

  Generally, in a thermal printer, printing is performed by selectively generating heat from a plurality of heating elements arranged in at least one row on a thermal head. Heat generation is performed by applying a drive pulse for a certain period of time. In addition to this drive pulse for heat generation (hereinafter referred to as the main pulse), at the start of printing, in order to compensate for the lack of energy and prevent blurring of printing. A sub-pulse with a short energization time is applied.

As described above, since printing is performed by heat generation, heat is accumulated in the thermal head as printing progresses, and if high-density patterns are continuously printed under high heat, the print may become thick or crushed due to heat storage. A malfunction occurs. In order to solve this problem, for example, in Patent Document 1, two types of sub-pulses are applied to the thermal head based on the dot printing state one dot before the current dot position and the cumulative value of the dot block including the current dot position. In addition, the energization time is adjusted by making the energization width of the main pulse variable.
JP-A-7-108701

  In the conventional heat storage control method, the sub-pulse for auxiliary heating is not changed in accordance with the heat storage information, unlike the main pulse. This is because the sub-pulse is relatively short with respect to the main pulse, so that it is considered that the influence on heat storage is low.

  However, for example, in the case of a print pattern in which the entire head heating element such as a barcode is used intermittently, history control is performed in which auxiliary heating by sub-pulses is performed on dots where the previous line is not printed. Compared with normal printing, printing crushing tends to occur. Referring to FIGS. 12 and 13, for example, the printing is more likely to be crushed as shown in FIG. 13 than the normal printing as shown in FIG. 12. FIG. 12 is a sample of barcode printing in a normal printing state. FIG. 13 is a sample of barcode printing in a crushing state.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a thermal printer that performs an appropriate correction that reflects heat storage information in a drive pulse for auxiliary heating.

In order to achieve the above object, a thermal printer according to a first aspect of the present invention provides a thermal head having a plurality of heat generating elements and a printing medium while moving relative to the printing medium for each line. in a thermal printer which performs dot printing in the main pulse is a drive voltage pulse for heating the heating element, selectively to the first pulse-applying means for indicia pressurized, the first pulse applied to the heating elements After the main pulse is applied by the means , a sub- pulse that is a drive voltage pulse for assisting heat generation of the heat generating element is selectively applied to the heat generating element to which the main pulse of one line before is not applied. a second pulse-applying means for applying, and the ambient temperature measuring means for measuring the environmental temperature around the thermal printer, the number of dots to be printed from a reference time And the total number of dots counting means for determining the sequential addition to the total number of dots, said from the total the total number of dots obtained by counting means dots, the predetermined number of dots corresponding to the measured the environment temperature by the environmental temperature measuring means by subtracting the multiplied by the elapsed time from the reference time, said adjustment means for adjusting the total number of dots, the difference of the number of dots and at the the number of dots after being adjusted reference by the adjusting means a heat storage coefficient setting means for setting a certain number of excess dots, and a heat storage coefficient corresponding to the environmental temperature measured by said environmental temperature measuring means, a voltage measuring means for measuring a head voltage applied to the thermal head, wherein Voltage fluctuation coefficient setting means for setting a voltage fluctuation coefficient corresponding to the head voltage measured by the voltage measurement means, and setting by the voltage fluctuation coefficient setting means Based on the heat storage coefficient set by the voltage fluctuation coefficient and the heat storage coefficient setting means which includes a first pulse width setting means for setting a first pulse width is applied pulse width of the main pulse, the first The correction coefficient setting means for setting a correction coefficient corresponding to the first pulse width set by the pulse width setting means, the voltage fluctuation coefficient set by the voltage fluctuation coefficient setting means, and the heat storage coefficient setting means. And a second pulse width setting means for setting a second pulse width that is an applied pulse width of the sub-pulse based on the heat storage coefficient and the correction coefficient set by the correction coefficient setting means , and the correction coefficient The setting means sets a value proportional to the first pulse width to the correction coefficient, and the second pulse width setting means has a large correction coefficient value. As described above, the second pulse width is set to be smaller.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the thermal storage coefficient setting means is a value proportional to the size of the excess dots and the size of the environmental temperature. Is set to the heat storage coefficient, and the first pulse width setting means sets the first pulse width to be smaller as the value of the heat storage coefficient is larger, and the second pulse width setting means is The second pulse width is set to be smaller as the value of the heat storage coefficient is larger .

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect of the invention, the voltage fluctuation coefficient setting means sets a value proportional to the magnitude of the head voltage to the voltage fluctuation. The first pulse width setting means sets the first pulse width to be smaller as the value of the voltage fluctuation coefficient is larger, and the second pulse width setting means is configured to reduce the voltage fluctuation. The second pulse width is set to be smaller as the coefficient value is larger .

According to the thermal printer according to claim 1 of the present invention also executes the regenerative control to the sub pulse for auxiliary heating. By shortening the pulse width adjusting energization time using the compensation coefficient to the heat storage coefficient similar to the main pulse. Thus, in the case of a printing pattern in which the auxiliary heating by the sub-pulses as intermittent use all head heating element is implemented by executing a heat storage control of the sub-pulses, the printing collapse is unlikely to occur.
Furthermore, the correction coefficient increases as the first pulse width increases. The larger the correction coefficient, the smaller the second pulse width. Therefore, when the application time of the main pulse is sufficiently long and there is no need for auxiliary heating, the application time of the sub pulse is shortened, and the occurrence of printing crushing can be avoided.

According to the second aspect of the present invention, in addition to the effect of the first aspect, the higher the number of excess dots and the environmental temperature, the larger the heat storage coefficient. As the heat storage coefficient increases, the first pulse width and the second pulse width become smaller. Therefore, when the environmental temperature is high and the heat storage is progressing, the application time of the main pulse and the sub pulse is shortened, and the occurrence of printing crushing can be avoided.

According to the third aspect of the present invention, in addition to the effect of the first or second aspect of the invention, the higher the head voltage, the larger the voltage variation coefficient. As the voltage variation coefficient increases, the first pulse width and the second pulse width become smaller. Therefore, when the head voltage is high, the application time of the main pulse and the sub pulse is shortened, and the occurrence of printing crushing can be avoided.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings based on embodiments embodying the tape printer. First, a schematic configuration of the tape printer according to the present embodiment will be described with reference to FIGS. 1A and 1B are schematic external views of a tape printer according to the present embodiment. FIG. 1A is a schematic upper external view, and FIG. 1B is a schematic right side external view. 2A and 2B are diagrams showing a schematic configuration of the thermal head of the tape printer according to the present embodiment, in which FIG. 2A is a plan view and FIG. 2B is a front view. FIG. 3 is a plan view when the cover of the tape cassette 35 mounted on the tape printer 1 is removed.

  As shown in FIG. 1, the tape printer 1 includes a character input key 2 for creating text composed of document data, a print key 3 for instructing printing of the text, and execution and selection of line feed commands and various processes. A keyboard 6 provided with a cursor key C for moving the cursor forward / backward / left / right on a liquid crystal display 7 for displaying characters such as characters over a plurality of lines, and a tape cassette 35 (to be described later) A cassette storage portion 8 for storing the housing (see FIG. 3) is covered with a storage cover 8A. A control board 12 that constitutes a control circuit unit is disposed below the keyboard 6, and a thermistor 13 for detecting environmental temperature is attached to the lower surface of the front end of the control board 12. Yes. Further, a label discharge port 16 through which a printed tape is discharged is formed on the left side surface portion of the cassette storage portion 8, and an adapter insertion port 17 to which a power adapter is attached is provided on the right side surface portion of the cassette storage portion 8. It has been. Since the thermistor 13 is provided at a location away from the thermal head 9, it is not affected by the heat generation drive of the thermal head 9.

    The cassette housing 8 includes a thermal head 9 (see FIG. 2) to be described later, a platen roller 10 facing the thermal head 9, a tape feeding roller 11 on the downstream side of the platen roller 10, and In addition to the tape drive roller shaft 14 facing the tape feed roller 11, an ink ribbon take-up shaft 15 for feeding an ink ribbon stored in the tape cassette 35 and the like are further arranged. The ribbon take-up shaft 15 is rotationally driven through a suitable drive mechanism from a tape feed motor 30 (see FIG. 4) constituted by a stepping motor or the like described later, and an ink ribbon 43 (after printing) (described later). 3 is inserted into an ink ribbon take-up reel 44 (see FIG. 3), and the ink ribbon take-up reel 44 is rotationally driven in synchronization with the printing speed. The tape drive roller shaft 14 is rotationally driven from the tape feed motor 30 through an appropriate transmission mechanism, and rotationally drives a tape drive roller 53 (see FIG. 3) described later.

  Further, as shown in FIG. 2, the thermal head 9 is a so-called thick film head formed in a substantially vertical rectangular flat plate shape, and a predetermined number (this embodiment) is formed on the left end edge of the front surface of the thermal head 9. The number of the heating elements R1 to Rn (n is a predetermined number) is arranged in a line along the side of the left edge. The other end of the flexible cable F connected to a connector (not shown) provided on the control board 12 is electrically connected to the right edge of the front surface of the thermal head 9 by soldering or the like. Further, the thermal head 9 has an arrangement direction of the heating elements R1 to Rn on the left end edge of the front surface of the substantially square heat sink 9A formed of a plated steel plate, a stainless steel plate or the like, and the left end edge of the heat sink 9A. It is fixed with an adhesive or the like so as to be parallel to the side of the plate. The upper right corner of the flexible cable F is fixed to the front surface of the heat sink 9A with a double-sided tape or the like. Furthermore, one end side of the flexible cable F is inserted into a horizontal substantially rectangular through-hole 9D formed in the lower end edge of the heat sink 9A, and is drawn out to the rear side. In addition, an extension portion 9B extending a predetermined width in a substantially right-angled front direction is formed at the lower end edge of the heat sink 9A, and four through holes 9C, 9C, 9C, 9C are formed. . The heat radiating plate 9A is arranged so that the arrangement direction of the heat generating elements R1 to Rn is substantially orthogonal to the transport direction of the print-receiving tape 36 (see FIG. 3) in the opening 52 (see FIG. 3) of the tape cassette 35. These are attached to the lower side of the cassette housing portion 8 by screws or the like through the through holes 9C, 9C, 9C, 9C.

  Next, as shown in FIG. 3, the tape cassette 35 includes a print-receiving tape 36 made of a transparent tape, an ink ribbon 43 for printing on the print-receiving tape 36, and a print-receiving tape 36 on which printing has been performed. The double-sided adhesive tape 46 to be backed is wound around a tape spool 37, a reel 42, and a tape spool 47, respectively, and can be rotated to a cassette boss 38, a reel boss 50, and a cassette boss 48 standing on the bottom surface of the cassette body 35B. Further, an ink ribbon take-up reel 44 for taking up the used ink ribbon 43 is further provided.

  Then, the unused ink ribbon 43 wound around the reel 42 and pulled out from the reel 42 is overlapped with the print-receiving tape 36 and enters the opening 52 together with the print-receiving tape 36, and the thermal head 9 and the platen roller 10. Pass between. Thereafter, the ink ribbon 43 is separated from the print-receiving tape 36, reaches the ink ribbon take-up reel 44 that is rotationally driven by the ribbon take-up shaft 15, and is taken up by the ink ribbon take-up reel 44.

  The double-sided pressure-sensitive adhesive tape 46 is wound around and stored on a tape spool 47 with the release paper facing outside, with the release paper superimposed on one side. The double-sided adhesive tape 46 pulled out from the tape spool 47 passes between the tape drive roller 53 and the tape feeding roller 11, and the adhesive surface on the side where the release paper is not superimposed is pasted on the print-receiving tape 36. Worn. In addition, spacers 46 </ b> A are inserted at both upper and lower ends of the double-sided adhesive tape 46.

  As a result, the print-receiving tape 36 wound around the tape spool 37 and drawn out from the tape spool 37 passes through the opening 52 in which the thermal head 9 of the tape cassette 35 is inserted. Thereafter, the print-receiving tape 36 to which the double-sided adhesive tape 46 is bonded is rotatably provided at one side lower part (lower left part in FIG. 3) of the tape cassette 35, and drives the tape feed motor 30 (see FIG. 4). The tape drive roller 53 that rotates in response to the tape drive roller 53 and the tape feed roller 11 disposed opposite to the tape drive roller 53 is sent to the outside of the tape cassette 35 to be labeled on the tape printer 1. It is discharged from the discharge port 16. In this case, the double-sided adhesive tape 46 is pressed against the print-receiving tape 36 by the tape drive roller 53 and the tape feeding roller 11.

  Next, the electrical configuration of the tape printer 1 will be described with reference to FIG. FIG. 4 is a block diagram showing a control configuration of the tape printer. As shown in FIG. 4, the control configuration of the tape printer 1 is configured with a control circuit unit 20 formed on the control board 12 as a core. The control circuit unit 20 includes a CPU 21 that controls each device, and an input / output interface 23, a CGROM 24, ROMs 25 and 26, and a RAM 27 connected to the CPU 21 via a data bus 22. A timer 210 is provided inside the CPU 21.

  Here, the CGROM 24 stores dot pattern data for display corresponding to the code data for each of a large number of characters.

  In addition, ROM (dot pattern data memory) 25 has print type dot pattern data for each of a large number of characters for printing characters such as alphabet letters and symbols, and the typeface (Gothic typeface, Mincho typeface, etc.) ), And for each typeface, six types (16, 24, 32, 48, 64, 96 dot sizes) of print character sizes are stored corresponding to the code data. In addition, graphic pattern data for printing a graphic image is also stored.

  Further, the ROM 26 reads out the display drive control program for controlling the LCDC 28 corresponding to the character code data such as characters and numbers inputted from the keyboard 6 and the data in the print buffer 272 to read the thermal head 9 and the tape feed motor 30. Print drive control program for driving the laser, a pulse number determination program for determining the number of pulses corresponding to the amount of energy formed for each print dot, a drive control program for each of the heating elements R1 to Rn of the thermal head 9, and other control of the tape printer 1 Various necessary programs are stored. The CPU 21 performs various calculations based on various programs stored in the ROM 26.

  Further, the RAM 27 is provided with a text memory 271, a print buffer 272, a line print dot number memory 273, a total print dot number memory 274, a parameter memory 275, etc. The text memory 271 is input from the keyboard 6. Document data is stored. Also, the print buffer 272 stores dot patterns for printing such as a plurality of characters and symbols, the number of applied pulses that are the amount of energy for forming each dot, and the like, and the thermal head 9 is stored in the print buffer 272. Dot printing is performed according to the dot pattern data. The line printing dot number memory 273 stores a count value of the number of printing dots for one line (128 dots in this embodiment) printed by the thermal head 9. Further, the total print dot number memory 274 stores the total print dot number from the start of printing by the thermal head 9. The parameter memory 275 stores various parameter tables as will be described later.

  The input / output interface 23 includes a keyboard 6, the thermistor 13, a display controller (hereinafter referred to as LCDC) 28 having a video RAM 281 for outputting display data to the LCD 7, and a drive for driving the thermal head 9. A circuit 29 and a drive circuit 31 for driving the tape feed motor 30 are connected to each other. Therefore, when characters or the like are input through the character keys of the keyboard 6, the text (document data) is sequentially stored in the text memory 271, and the keyboard is based on the dot pattern generation control program and the display drive control program. A dot pattern corresponding to a character or the like input via 6 is displayed on the LCD 7. The thermal head 9 is driven via a drive circuit 29 to print the dot pattern data stored in the print buffer 272. In synchronization with this, the tape feed motor 30 controls the tape feed via the drive circuit 31. I do. Here, the thermal head 9 prints characters or the like on the tape by selectively driving the heating elements R1 to Rn corresponding to the printing dots for one line via the drive circuit 29.

  Here, various parameter tables stored in the parameter memory 275 will be described with reference to FIGS. FIG. 5 is a schematic diagram showing a data configuration of the dot number parameter table 61. FIG. 6 is a schematic diagram illustrating a data configuration of the heat storage coefficient table 62. FIG. 7 is a schematic diagram showing a data configuration of the voltage variation coefficient table 63. FIG. 8 is a schematic diagram showing a data configuration of the correction coefficient table 64 for correcting the heat storage coefficient d.

  As shown in FIG. 5, the dot number parameter table 61 includes an environmental temperature 611 indicating a temperature measured via the thermistor 13, a total amount 612 corresponding to the environmental temperature 611, and an outflow amount 613. This total amount 612 is the maximum total number of printable dots that can be continuously printed, which is determined by the environmental temperature or the like. As described later, the print dots of the heating elements R1 to Rn of the thermal head 9 that rise by continuous printing are crushed. It represents the heat storage temperature that guarantees that it will not occur. The outflow amount 613 is the number of dots to be subtracted from the total number of printed dots every predetermined time (about 1 second in this embodiment) as will be described later. The outflow amount 613 includes (1) material, shape and size of the thermal head 9, (2) material, shape and size of the heat sink 9A, and (3) adhesion between the thermal head 9 and the heat sink 9A. The material and thickness of the agent, (4) the joining method of the heat sink 9A and the mechanical frame of the tape printer 1, (5) the material, shape and size of this mechanical frame, and (6) printing determined by the environmental temperature, etc. This is the number of dots, and represents the amount of natural heat released through the heat sink 9A of the thermal head 9 and the like.

  In the environmental temperature 611 of the dot number parameter table 61, three types of environmental temperature ranges of “30 ° C. or higher”, “20 ° C. or higher and lower than 30 ° C.”, and “less than 20 ° C.” are registered in advance. The total amount 612 for each environmental temperature 611 includes “250,000 dots” for the environmental temperature 611 “30 ° C. or higher”, “300000 dots” for the environmental temperature 611 “20 ° C. or higher and lower than 30 ° C.” For the environmental temperature 611 “less than 20 ° C.”, “460000 dots” is registered in advance as the total amount 612. The outflow 613 for each environmental temperature 611 includes “1800 dots” for “30 ° C. or higher” of the environmental temperature 611, “2000 dots” for “20 ° C. or higher and lower than 30 ° C.” of the environmental temperature 611, For the environmental temperature 611 “less than 20 ° C.”, “2600 dots” is registered in advance as the outflow amount 613. The total amount 612 and the outflow amount 613 corresponding to each environmental temperature 611 are parameters that can be changed to arbitrary numerical values in accordance with a change in the natural heat dissipation amount of the thermal head 9 due to a change in the shape of the heat sink 9A.

  Next, as shown in FIG. 6, the heat storage coefficient table 62 uses the total amount obtained by the dot number parameter table 61 of FIG. 5 as a reference value, and the number of excess dots in the current total number of dots that exceeds the reference value. 621 and the value of the heat storage coefficient d determined corresponding to the environmental temperature 622 measured through the thermistor 13 are stored in advance. Here, the value of “total amount” determined by the dot number parameter table 61 is used as the reference value for obtaining the excess dot number 621. The environmental temperature 622 is divided into five levels of “40 to 32 ° C.”, “31 to 28 ° C.”, “27 to 22 ° C.”, “21 to 17 ° C.”, and “16 to 10 ° C.”. A heat storage coefficient d is determined corresponding to the excess dot number 621. This heat storage coefficient d is used when re-evaluating the energy applied to the heat generating element in the heat storage control process described later, and determines a value to be subtracted to correct the applied energy corresponding to the accumulated temperature of the thermal head 9. Used for. If the number of excess dots 621 is the same, the value of the heat storage coefficient d increases as the environmental temperature 622 increases, and the value of the heat storage coefficient d increases as the number of excess dots increases if the environmental temperature 622 is the same. Therefore, in a state where the environmental temperature 622 is high and the number of excess dots 621 is large and the heat storage is advanced, the value of the heat storage coefficient d is large, so that the energization time is shortened and the heat storage print is not crushed. The heat storage coefficient d is subject to correction for both the temperature rise process (non-steady time) and saturation (steady time).

  Next, as shown in FIG. 7, the voltage variation coefficient table 63 includes a voltage variation coefficient that is a constant used to change the pulse width applied according to the voltage when setting the energy applied to each heating element. The voltage center value 631, a voltage range (hexadecimal data value) 632 corresponding to the voltage center value 631, and a voltage variation coefficient C (V) 633 corresponding to the voltage range 632. In FIG. 7, the value of the voltage variation coefficient C (V) is also described in hexadecimal data. The higher the voltage value, the shorter the energization time required for heat generation. Therefore, the higher the voltage value, the higher the value of the voltage variation coefficient C (V). As will be described later, since the heating element is controlled to be turned off when the value of C (V) is subtracted from the fixed value and becomes 0, the value of C (V) increases as the voltage increases. For example, the applied energy is adjusted so as to shorten the drive pulse application time.

  Next, as shown in FIG. 8, the correction coefficient table 64 defines a correction coefficient M for correcting the heat storage coefficient d used for the sub-pulse, and includes a main pulse width 641, a main pulse loop count 642, It consists of a correction coefficient M643. In the present embodiment, the main pulse width 641 re-evaluates the applied energy every 250 microseconds in this embodiment, and determines the pulse application time to the heating element. Therefore, the correction coefficient M643 is determined according to the number of loops 642 for this period Determined. As the number of loops increases, the value of the correction coefficient M increases, and in a situation where the main pulse application time is long and heat storage is progressing, correction is performed so as not to cause print crushing by shortening the sub-pulse application time. The value of the correction coefficient M643 is a parameter that is set in advance and can be changed according to the type of the thermal head 9 of the tape printer and other environments. In this embodiment, the correction coefficient M is set in proportion to the applied pulse width of the main pulse, but it may be a fixed value such as 1.25 instead of the proportional coefficient.

  Next, the tape printing operation of the tape printer 1 configured as described above will be described with reference to the flowcharts of FIGS. FIG. 9 is a flowchart showing a flow of heat storage control processing of the tape printer 1. FIG. 10 is a flowchart showing the flow of the main pulse application process executed in S25 of FIG. FIG. 11 is a flowchart showing the flow of the sub-pulse application process executed in S27 of FIG.

  First, when the power is turned on and the processing of the tape printer 1 is started, the ambient temperature is acquired from the thermistor 13 (S1). Next, printing is started in accordance with an instruction from the user (S3). Note that the timer 210 starts counting when printing is started (S5). Next, the type of tape included in the tape cassette 35 attached to the tape printer 1 is detected based on a signal from the tape type detection sensor (S7).

  Next, the temperature coefficient t, the total amount initial value (reference dot number), and the outflow amount are determined based on the environmental temperature acquired in S1 (S9). The temperature coefficient t is calculated by an equation such as t = a / temperature AD value + b (a and b are fixed values) with respect to the AD conversion value of the environmental temperature. Used when determining the applied energy. As the total amount value and the outflow amount, a value corresponding to the environmental temperature is substituted according to the dot number parameter table 61 stored in the parameter memory 275. The total amount and the outflow amount are stored in the total print dot number memory 274 of the RAM 27.

  Next, data for one line for executing printing is input, and the corresponding dot number for one line is stored in the one-line print dot number memory 273 of the RAM 27 (S11). Then, the total number of dots D is calculated by adding the number of dots for one line stored in the one-line print dot number memory 273 in S11 to the total amount determined in S9 (S13). Next, the total number of dots D calculated in S13 is subtracted by multiplying the outflow amount determined in S9 by the elapsed time from the start of printing to adjust the number of dots (S15). By the processing in S13 and S15, the number of dots D is obtained by adding the number of dots for one line to be printed from the total amount determined in S9 and multiplying the outflow amount determined in S9 by the elapsed time from the start of printing. Is subtracted (total number of dots ← total amount + number of printed dots−outflow amount × elapsed time). In this way, the temperature accumulation state of the thermal head 9 can be expressed by the number of dots by sequentially adding the number of printed dots, converting the heat dissipation amount to the number of dots, and subtracting from the number of printed dots. it can.

  Next, the heat storage coefficient d is set based on the excess dot number that is the difference between the dot number D adjusted in S15 and the reference dot number (total amount initial value set in S9) and the environmental temperature acquired in S6 (S17). ). The heat storage coefficient d is determined according to the heat storage coefficient table 62 stored in the parameter memory 275. In the first processing, since the difference between the current dot number D and the reference dot number is 50000 or less, the heat storage coefficient d is 1 regardless of the environmental temperature.

  Next, the voltage applied to the thermal head 9 is acquired from the voltage measuring unit 34 (S19). Then, a voltage variation coefficient C (V) is set based on the acquired voltage (S23). The voltage variation coefficient C (V) is determined in accordance with the voltage variation coefficient table 63 stored in the parameter memory 275, and is used in main pulse application processing and sub-pulse application processing described later.

  Next, main pulse application processing for setting a main pulse to be applied to the heating element is executed (S25). Details of the main pulse application processing will be described later with reference to FIG. When the pulse application process is completed, a sub-pulse application process for setting a sub-pulse is executed (S27). Details of the sub-pulse application process will be described later with reference to FIG. When the sub-pulse application process is completed, it is determined whether or not printing is continued (S29). If it is continued (S29: YES), the process returns to S11 to input the next one line of data. When not continuing (S29: NO), a process is complete | finished.

  Next, details of the main pulse application process executed in S25 of FIG. 9 will be described with reference to FIG. First, the pulse width (energization time) applied to each heating element is set by substituting a predetermined value for the application control coefficient C (S101). Here, the value substituted for the application control coefficient C is a fixed value determined in advance corresponding to the thermal head 9 and the type of tape acquired in S7. From this fixed value, a value corresponding to the environmental temperature, voltage, and heat storage status is subtracted at predetermined time intervals according to the calculation formula described later, and energy is applied to the heating element until the value of C becomes 0 (energization is performed). ). Here, for example, 55400 is substituted for C.

  Next, the loop counter L is cleared (S102). The loop counter L counts the number of executions of reevaluation of applied energy every 250 microseconds described later. Next, it is determined whether or not the application control coefficient C is less than 0 (S103). If C is 0 or more (S103: NO), a drive pulse is applied to turn on the heating element (S105). Then, it is determined whether 250 microseconds have elapsed (S107). Until 250 microseconds have elapsed (S107: NO), the application of the drive pulse is continued (S105).

  When 250 microseconds have elapsed (S107: YES), 1 is added to the loop counter L (S108), and the value of the application control coefficient C is recalculated to determine whether or not the drive pulse application should be continued. Then, the amount of energy to be applied in the future is determined (S109). This re-evaluation of the applied energy is performed by a calculation formula of C ← C−C (V) × t × d. The voltage variation coefficient C (V) increases as the voltage value increases, the temperature coefficient t increases as the environmental temperature increases, and the value of the heat storage coefficient d increases as the number of excess dots and the environmental temperature increase. Therefore, the value derived by multiplying all these factors becomes large when the environmental temperature is high and the thermal storage of the thermal head 9 is progressing due to continuation of printing. If the value of the multiplication result is subtracted from the value of C to obtain a new value of C, the value of C becomes smaller when heat storage is progressing. When C becomes less than 0 in S103, the main pulse application process is terminated and the process proceeds to the sub-pulse application process. Therefore, when heat storage is progressing, the energization time is shortened, and the occurrence of print crushing can be avoided.

  Thereafter, the process returns to S103, and it is determined again whether or not the value of C calculated by S109 is less than zero. When C becomes less than 0 (S103: YES), the process returns to the main routine of the heat storage control in FIG.

  Next, the details of the sub-pulse application process executed in S27 of FIG. 9 will be described with reference to FIG. Note that the sub-pulse applied for the purpose of assisting the rising of the main pulse is applied to the heating element when the previous line is not printed. First, the pulse width (energization time) applied to each heating element is set by substituting a predetermined value for the application control coefficient C (S201). This is a fixed value determined in advance corresponding to the type of tape acquired in thermal heads 9 and S7. From this fixed value, a value corresponding to the environmental temperature, voltage, and heat storage status is subtracted at predetermined time intervals according to the calculation formula described later, and energy is applied to the heating element until the value of C becomes 0 (energization is performed). ).

  Next, the value of the loop counter L is read, the correction coefficient table 64 is searched, and the correction coefficient M is set (S202). For example, if the applied energy reevaluation process is performed three times every 250 microseconds in the main pulse application process, the correction coefficient M is 1.03.

  Next, it is determined whether or not the application control coefficient C is less than 0 (S203). If C is 0 or more (S203: NO), a drive pulse is applied to turn on the heating element (S205). Then, it is determined whether 250 microseconds have elapsed (S207). Until 250 microseconds have elapsed (S207: NO), application of the drive pulse is continued (S205).

  When 250 microseconds have elapsed (S207: YES), the value of the application control coefficient C is recalculated to determine whether the application of the drive pulse should be continued, and the amount of energy to be applied in the future is determined (S209). ). The re-evaluation of the applied energy is performed by a calculation formula of C ← C−C (V) × t × d × M (n). The voltage variation coefficient C (V) increases as the voltage value increases, the temperature coefficient t increases as the environmental temperature increases, and the value of the heat storage coefficient d increases as the number of excess dots and the environmental temperature increase. The value of the coefficient M increases as the width of the main pulse increases. Therefore, the value derived by multiplying all of these factors increases when the environmental temperature is high and the thermal storage of the thermal head 9 is progressing due to continuation of printing, and further increases as the application time of the main pulse increases. When the value of the multiplication result is subtracted from the value of C to obtain a new value of C, when the heat storage is advanced and the energization time of the main pulse is long, the value of C becomes smaller. When C becomes less than 0 in S203, the application of the sub-pulse to the heating element is completed. Therefore, when the heat storage is advanced or when the energization time of the main pulse is sufficiently long and no auxiliary heating is required, the energization time Is shortened, and the occurrence of print crushing can be avoided.

  Thereafter, the process returns to S203, and it is determined again whether or not the value of C calculated by S209 is less than zero. When C becomes less than 0 (S203: YES), the heating element is turned off for a predetermined time (S211), and the head is cooled. And it returns to the main routine of the heat storage control of FIG.

  As described above, according to the tape printer 1 of the present embodiment, the value of the heat storage coefficient d of the subpulse is corrected by the correction coefficient M proportional to the pulse width of the main pulse, the width of the subpulse is determined, and the heating element. If the main pulse is energized for a long time and auxiliary heating is not required for fading, the sub-pulse width can be reduced to shorten the energization. Even in the case of a pattern in which all of the head heating elements are used intermittently, such as barcode printing, it is possible to avoid the occurrence of printing collapse due to excessive auxiliary heating by history control.

In the above embodiment, the CPU 21 that executes the heating element ON in S105 of the flowchart of FIG. 10 functions as the first pulse applying unit of the present invention, and the CPU 21 that executes the heating element ON in S205 of the flowchart of FIG. It functions as the second pulse applying means of the present invention. The CPU 21 that measures the environmental temperature in S1 of the flowchart of FIG. 9 functions as the environmental temperature measuring means of the present invention, and the CPU 21 that adds the number of print dots in S13 functions as the total dot number counting means of the present invention, and flows out in S15. The CPU 21 that subtracts the amount functions as the adjusting means of the present invention, the CPU 21 that acquires the heat storage coefficient d in S17 functions as the heat storage coefficient setting means of the present invention, and the CPU 21 that acquires the head voltage in S19 is the voltage measurement of the present invention. The CPU 21 that functions as the means and sets the voltage variation coefficient C (V) in S23 functions as the voltage variation coefficient setting means of the present invention. The CPU 21 that executes the main pulse application process in S25 and the flowchart of FIG. 10 functions as the first pulse width setting means of the present invention. The CPU 21 that sets the correction coefficient M in S202 of the flowchart of FIG. 11 functions as the correction coefficient setting means of the present invention. The CPU 21 that performs the sub-pulse application process in the flowchart of FIG. 9 and the flowchart of FIG. 11 functions as the second pulse width setting means of the present invention.

  In addition, this invention is not limited to the said embodiment, A various change is possible. For example, the tape printer 1 has a keyboard 6 and prints text input from the keyboard 6 on a tape. The tape printer 1 is connected to an external device such as a personal computer, and print data is transferred to the external device. May be received and printed.

  The ambient temperature is not limited to that measured by the thermistor 13 installed in the tape printer 1, and the temperature around the tape printer 1 may be measured and transmitted to the tape printer 1.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic external view of the tape printer concerning this embodiment, (A) is a general | schematic upper external view, (B) is a schematic right side external view. It is a figure which shows schematic structure of the thermal head of the tape printer which concerns on this embodiment, (A) is a top view, (B) is a front view. It is a top view at the time of removing the cover of the tape cassette 35 with which the tape printer 1 is mounted | worn. It is a block diagram which shows the control structure of a tape printer. 6 is a schematic diagram showing a data configuration of a dot number parameter table 61. FIG. It is a schematic diagram which shows the data structure of the thermal storage coefficient table 62. 6 is a schematic diagram showing a data configuration of a voltage variation coefficient table 63. FIG. It is a schematic diagram which shows the data structure of the correction coefficient table 64 for correct | amending the thermal storage coefficient d. 3 is a flowchart showing a flow of heat storage control processing of the tape printer 1. It is a flowchart which shows the flow of the main pulse application process performed by S25 of FIG. It is a flowchart which shows the flow of the subpulse application process performed by S27 of FIG. This is a sample of barcode printing in a normal printing state. This is a sample of barcode printing in a crushing state.

DESCRIPTION OF SYMBOLS 1 Tape printer 9 Thermal head 20 Control circuit part 21 CPU
27 RAM
35 Tape cassette 36 Label tape 273 Line printing dot number memory 274 Total printing dot number memory 275 Parameter storage area

Claims (3)

In a thermal printer that performs dot printing for each print medium while relatively moving a thermal head having a plurality of heating elements and the print medium,
The main pulse is a drive voltage pulse for heating the heating element, a first pulse-applying means for selectively indicia pressurized against the heating elements,
After the main pulse is applied by the first pulse applying means , a sub- pulse, which is a drive voltage pulse for assisting heat generation of the heat generating element, is applied to the heat generating element to which the main pulse before one line is not applied. Second pulse applying means for selectively applying to the second pulse applying means;
Environmental temperature measuring means for measuring the environmental temperature around the thermal printer;
A total dot number counting means for obtaining the total number of dots by sequentially adding the number of dots printed from the reference time;
By subtracting, from the total number of dots obtained by the total number of dots counting means, a predetermined number of dots corresponding to the environmental temperature measured by the environmental temperature measuring means multiplied by the elapsed time from the reference time. Adjusting means for adjusting the total number of dots ;
Heat storage coefficient setting a heat storage coefficient corresponding to the environmental temperature the excess dot count being a difference, and measured by the environmental temperature measuring means with the number of dots when the number of dots and the reference after being adjusted by said adjusting means Setting means;
Voltage measuring means for measuring a head voltage applied to the thermal head;
Voltage fluctuation coefficient setting means for setting a voltage fluctuation coefficient corresponding to the head voltage measured by the voltage measurement means;
A first pulse that sets a first pulse width that is an applied pulse width of the main pulse based on the voltage fluctuation coefficient set by the voltage fluctuation coefficient setting means and the heat storage coefficient set by the heat storage coefficient setting means Width setting means;
Correction coefficient setting means for setting a correction coefficient corresponding to the first pulse width set by the first pulse width setting means;
Based on the voltage fluctuation coefficient set by the voltage fluctuation coefficient setting means, the heat storage coefficient set by the heat storage coefficient setting means , and the correction coefficient set by the correction coefficient setting means , the application pulse of the sub- pulse A second pulse width setting means for setting a second pulse width which is a width ,
The correction coefficient setting means sets a value proportional to the magnitude of the first pulse width as the correction coefficient,
The thermal printer, wherein the second pulse width setting means sets the second pulse width to be smaller as the correction coefficient is larger . The heat storage coefficient setting means sets a value proportional to the size of the excess dot number and the environmental temperature to the heat storage coefficient,
The first pulse width setting means sets the first pulse width to be smaller as the value of the heat storage coefficient is larger,
2. The thermal printer according to claim 1, wherein the second pulse width setting unit sets the second pulse width to be smaller as the value of the heat storage coefficient is larger . The voltage variation coefficient setting means sets a value proportional to the magnitude of the head voltage to the voltage variation coefficient,
The first pulse width setting means sets the first pulse width to be smaller as the value of the voltage variation coefficient is larger,
Said second pulse width setting means, as the value of the voltage variation coefficient is large, the thermal printer according to claim 1 or 2, wherein the second pulse width and sets so smaller.

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