Patent Grant
7271819
The disclosure relates to a thermal printer, and more particularly to a thermal printer that controls heat buildup in a thermal head thereof.
A thermal printer generally has a plurality of heating elements which are arrayed in at least one row on a thermal head. Drive pulses are selectively applied to the heating elements to generate heat for printing. The heat accumulates or builds up in the thermal head as printing proceeds, and print characteristics or print performance of the thermal printer can be adversely affected by this heat buildup in the thermal head. For example, printing high-density patterns continuously under hot conditions can lead to problems such as fattened or illegible letters (or patterns) due to the heat buildup. Some thermal printers have been proposed to overcome such problem.
For example, as disclosed in Japanese patent-application publication No. 2001-270144, a thermal printer calculates heat buildup data that indicates a heat buildup state in each heat buildup layer (a glaze layer, a ceramic plate, and an aluminum plate) of its thermal head, and multiplies the heat buildup data by predetermined coefficients, thereby obtaining heat buildup correction data. The thermal printer then obtains heat generation data based on the heat buildup correction data, and controls driving of heating elements based on the heat generation data. The aluminum plate is provided with a head temperature sensor that measures temperature of the thermal head. A coefficient to be used to obtain the heat buildup correction data for the aluminum plate is determined by an equation that includes a head voltage as a parameter.
Another thermal printer applies, in addition to main drive pulses, sub-pulses (subsidiary pulses) having a short ON time in order to compensate for any energy insufficiency at the start of printing and to prevent print blurring. For example, Japanese patent-application publication No. 7-108701 discloses a thermal printer that applies two types of sub-pulse to the thermal head based on a dot print state at the current dot and at the dot before the current dot. The thermal printer also adjusts the ON time by changing the width of the main pulses.
It is known that a pulse width applied to the heating elements are controlled in consideration of load fluctuations, when a voltage of a power source is not constant (such as when a stabilized power source like a DC/DC converter is not used). This control method is called unstable control. In the unstable control, when a dot count (a number of dots) to be printed is high, a current is also high and thus a voltage drop is large. On the other hand, when the dot count to be printed is low, the current is also low and thus the voltage drop is small. For that reason, there arises a time difference for a temperature rise of the heating elements between the high voltage state and the low voltage state. A thermal printer disclosed in Japanese patent-application publication No. 8-300713 reads out the voltage every time Δt, determines an OFF time for application pulses based on the read voltage, and repeats ON and OFF of the pulses based on the OFF time. In this way, the thermal printer provides a stable heat generation of the thermal head.
A thermal printer disclosed in Japanese patent-application publication No. 2001-191574 calculates a heat buildup level for each heating element based on a number of drive pulses which have been applied over a plurality of times. The thermal printer applies, to each heating element, a number of drive pulses that corresponds to the heat buildup level. In this way, size and density of a dot pattern to be recorded by each heating element is made uniform.
However, with the above-described thermal printers, it is difficult to appropriately determine an amount of the heat buildup and to set the width of the pulses applied to the heating elements in consideration of a voltage difference or a situation in which the tape-type has changed.
In view of the foregoing, it is an object of the disclosure to provide a thermal printer that performs effective heat buildup control even when a power source having a comparatively low voltage is used or when the voltage of the power source is not constant.
It is another object of the disclosure to provide a thermal printer that performs effective heat buildup control even after a change of printing-medium type, thereby maintaining a high print quality.
In order to attain the above and other objects, the disclosure provides a thermal printer. The thermal printer includes a thermal head, a pulse application portion, a voltage measurement portion, a total-dot counting portion, an adjustment portion, a heat-buildup-coefficient storing portion, a pulse-width setting portion, and a pulse-width correction portion. The thermal head has a plurality of heating elements and is movable relative to a printing medium for printing dots on the printing medium. The pulse application portion applies a drive voltage pulse selectively to the heating elements. The drive voltage pulse has a width. The voltage measurement portion measures a head voltage applied to the thermal head. The total-dot counting portion adds a number of dots which are printed from a reference time point, thereby obtaining a total dot count. The adjustment portion adjusts the total dot count based on a predetermined adjustment dot count corresponding to an ambient temperature. The heat-buildup-coefficient storing portion stores a heat buildup coefficient corresponding both to the ambient temperature and to an excess dot count. The excess dot count is a difference between the total dot count after adjustment by the adjustment portion and a predetermined reference dot count. The pulse-width setting portion sets the width of the drive voltage pulse based on the head voltage and the heat buildup coefficient. The pulse-width correction portion corrects the width of the drive voltage pulse based on the head voltage measured by the voltage measurement portion.
The disclosure also provides a thermal printer. The thermal printer includes a thermal head, a pulse application portion, a voltage measurement portion, a printing-medium detection portion, a total-dot counting portion, an adjustment portion, a heat-buildup-coefficient storing portion, a pulse-width setting portion, and a pulse-width correction portion. The thermal head has a plurality of heating elements and is movable relative to a printing medium for printing dots on the printing medium. The pulse application portion applies a drive voltage pulse selectively to the heating elements. The drive voltage pulse has a width. The voltage measurement portion measures a head voltage applied to the thermal head. The printing-medium detection portion detects a printing-medium type. The total-dot counting portion adds a number of dots which are printed from a reference time point, thereby obtaining a total dot count. The adjustment portion adjusts the total dot count based on a predetermined adjustment dot count corresponding to an ambient temperature. The heat-buildup-coefficient stores portion storing a heat buildup coefficient corresponding both to the ambient temperature and to an excess dot count. The excess dot count is a difference between the total dot count after adjustment by the adjustment portion and a predetermined reference dot count. The pulse-width setting portion sets the width of the drive voltage pulse based on the head voltage and the heat buildup coefficient. The pulse-width correction portion corrects the width of the drive voltage pulse based on the printing-medium type detected by the printing-medium detection portion.
The disclosure also provides a thermal printer. The thermal printer includes a thermal head, a pulse application portion, a power source, a voltage measurement portion, and a pulse-width setting portion. The thermal head has a plurality of heating elements and is movable relative to a printing medium for printing dots on the printing medium. The pulse application portion applies a drive voltage pulse selectively to the heating elements. The drive voltage pulse has a width. The power source supplies the thermal head with electrical power. The voltage measurement portion measures the voltage of the power source at predetermined time intervals. The pulse-width setting portion sets the width of the drive voltage pulse based on a parameter corresponding to the voltage measured by the voltage measurement portion. The voltage measurement portion performs an initial measurement after the pulse application portion has started applying the drive voltage pulse.
The disclosure also provides a thermal printer. The thermal printer includes a thermal head, a pulse application portion, a printing-medium detection portion, a printing-medium storage portion, a total-dot counting portion, an adjustment portion, a pulse-width setting portion, and a pulse-width correction portion. The thermal head has a plurality of heating elements and is movable relative to a printing medium for printing dots on the printing medium. The pulse application portion applies a drive voltage pulse selectively to the heating elements. The drive voltage pulse has a width. The printing-medium detection portion detects a printing-medium type. The printing-medium storage portion stores the printing-medium type detected by the printing-medium detection portion. The printing-medium monitor portion monitors a current printing-medium type detected by the printing-medium detection portion and a previous printing-medium type that was detected previously and is stored in the printing-medium storage portion. The total-dot counting portion adds a number of dots which are printed from a reference time point, thereby obtaining a total dot count. The adjustment portion adjusts the total dot count based on a predetermined adjustment dot count corresponding to an ambient temperature. The pulse-width setting portion sets the width of the drive voltage pulse based on a difference between the total dot count after adjustment by the adjustment portion and a predetermined reference dot count. The pulse-width correction portion corrects the width of the drive voltage pulse, when the printing-medium monitor portion has determined that the current printing-medium type is different from the previous printing-medium type.
The disclosure also provides a thermal printer. The thermal printer includes a thermal head, a heat-buildup-coefficient memory, a pulse application portion, a voltage measurement portion, and a controller. The thermal head has a plurality of heating elements and is movable relative to a printing medium for printing dots on the printing medium. The heat-buildup-coefficient memory stores a heat buildup coefficient. The pulse application portion applies a drive voltage pulse selectively to the heating elements. The drive voltage pulse has a width. The voltage measurement portion measures a head voltage applied to the thermal head. The controller adds a number of dots which are printed from a reference time point for obtaining a total dot count, adjusts the total dot count based on a predetermined adjustment dot count corresponding to an ambient temperature, sets the width of the drive voltage pulse based on the head voltage and the heat buildup coefficient, and corrects the width of the drive voltage pulse based on the head voltage measured by the voltage measurement portion. The heat buildup coefficient corresponds both to the ambient temperature and to an excess dot count that is a difference between the total dot count after adjustment and a predetermined reference dot count.
The disclosure also provides a thermal printer. The thermal printer includes a thermal head, a heat-buildup-coefficient memory, a pulse application portion, a voltage measurement portion, a printing-medium detector, and a controller. The thermal head has a plurality of heating elements and is movable relative to a printing medium for printing dots on the printing medium. The heat-buildup-coefficient memory stores a heat buildup coefficient. The pulse application portion applies a drive voltage pulse selectively to the heating elements. The drive voltage pulse has a width. The voltage measurement portion measures a head voltage applied to the thermal head. The printing-medium detector detects a printing-medium type. The controller adds a number of dots which are printed from a reference time point for obtaining a total dot count, adjusts the total dot count based on a predetermined adjustment dot count corresponding to an ambient temperature, sets the width of the drive voltage pulse based on the head voltage and the heat buildup coefficient, and corrects the width of the drive voltage pulse based on the printing-medium type detected by the printing-medium detector. The heat buildup coefficient corresponds both to the ambient temperature and to an excess dot count that is a difference between the total dot count after adjustment and a predetermined reference dot count.
The disclosure also provides a thermal printer. The thermal printer includes a thermal head, a pulse application portion, a power source, a voltage measurement portion, and a controller. The thermal head has a plurality of heating elements and is movable relative to a printing medium for printing dots on the printing medium. The pulse application portion applies a drive voltage pulse selectively to the heating elements. The drive voltage pulse has a width. The power source supplies the thermal head with electrical power. The power source has a voltage. The voltage measurement portion measures a voltage of the power source at predetermined time intervals. The controller sets the width of the drive voltage pulse based on a parameter corresponding to the voltage measured by the voltage measurement portion. The controller controls the voltage measurement portion to perform an initial measurement after the pulse application portion has started applying the drive voltage pulse.
The disclosure also provides a thermal printer. The thermal printer includes a thermal head, a pulse application portion, a printing-medium detector, a printing-medium memory, and a controller. The thermal head has a plurality of heating elements and is movable relative to a printing medium for printing dots on the printing medium. The pulse application portion applies a drive voltage pulse selectively to the heating elements. The drive voltage pulse has a width. The printing-medium detector detects a printing-medium type. The printing-medium memory stores the printing-medium type detected by the printing-medium detector. The controller monitors a current printing-medium type detected by the printing-medium detector and a previous printing-medium type that was detected previously and is stored in the printing-medium memory, adds a number of dots which are printed from a reference time point for obtaining a total dot count, adjusts the total dot count based on a predetermined adjustment dot count corresponding to an ambient temperature, sets the width of the drive voltage pulse based on a difference between the total dot count after adjustment and a predetermined reference dot count, and corrects the width of the drive voltage pulse upon determining that the current printing-medium type is different from the previous printing-medium type.
The disclosure also provides a method of controlling heat buildup in a thermal printer. The thermal printer includes a thermal head and a heat-buildup-coefficient storage portion. The thermal head has a plurality of heating elements and is movable relative to a printing medium for printing dots on the printing medium. The method includes applying a drive voltage pulse selectively to the heating elements, the drive voltage pulse having a pulse width, measuring a head voltage applied to the thermal head, adding a number of dots which are printed from a reference time point for obtaining a total dot count, adjusting the total dot count based on a predetermined adjustment dot count corresponding to an ambient temperature, setting the pulse width of the drive voltage pulse based on the head voltage and a heat buildup coefficient stored in the heat-buildup-coefficient storage portion, and correcting the pulse width of the drive voltage pulse based on the head voltage measured in the step of measuring the head voltage. The heat buildup coefficient corresponds both to the ambient temperature and to an excess dot count. The excess dot count is a difference between the total dot count after adjustment in the step of adjusting the total dot count and a predetermined reference dot count.
The disclosure also provides a method of controlling heat buildup in a thermal printer. The thermal printer includes a thermal head and a heat-buildup-coefficient storage portion. The thermal head has a plurality of heating elements and is movable relative to a printing medium for printing dots on the printing medium, The method includes applying a drive voltage pulse selectively to the heating elements, the drive voltage pulse having a pulse width, measuring a head voltage applied to the thermal head, detecting a printing-medium type, adding a number of dots which are printed from a reference time point for obtaining a total dot count, adjusting the total dot count based on a predetermined adjustment dot count corresponding to an ambient temperature, setting the pulse width of the drive voltage pulse based on the head voltage and a heat buildup coefficient stored in the heat-buildup-coefficient storage portion, and correcting the pulse width of the drive voltage pulse based on the printing-medium type detected in the step of detecting the printing-medium type. The heat buildup coefficient corresponds both to the ambient temperature and to an excess dot count. The excess dot count is a difference between the total dot count after adjustment in the step of adjusting the total dot count and a predetermined reference dot count.
The disclosure also provides a method of controlling heat buildup in a thermal printer. The thermal printer includes a thermal head and a power source. The thermal head has a plurality of heating elements and is movable relative to a printing medium for printing dots on the printing medium. The power source has a voltage and supplies the thermal head with electrical power. The method includes applying a drive voltage pulse selectively to the heating elements, the drive voltage pulse having a pulse width, measuring the voltage of the power source at predetermined time intervals, and setting the pulse width of the drive voltage pulse based on a parameter corresponding to the voltage measured in the step of measuring the voltage. The step of measuring the voltage includes performing an initial measurement after a start of applying the drive voltage pulse.
The disclosure also provides a method of controlling heat buildup in a thermal printer. The thermal printer includes a thermal head. The thermal head has a plurality of heating elements and is movable relative to a printing medium for printing dots on the printing medium. The method includes applying a drive voltage pulse selectively to the heating elements, the drive voltage pulse having a pulse width, detecting a printing-medium type, storing the printing-medium type detected in the step of detecting the printing-medium type, monitoring a current printing-medium type detected in the step of detecting the printing-medium type and a previous printing-medium type that was detected previously and is stored in the step of storing the printing-medium type, adding a number of dots which are printed from a reference time point for obtaining a total dot count, adjusting the total dot count based on a predetermined adjustment dot count corresponding to an ambient temperature, setting the pulse width of the drive voltage pulse based on a difference between the total dot count after adjustment in the step of adjusting the total dot count and a predetermined reference dot count, and correcting the pulse width of the drive voltage pulse, upon determining, in the step of monitoring the printing-medium type, that the current printing-medium type is different from the previous printing-medium type.
The above and other objects, features and advantages of the disclosure will become more apparent from reading the following description of the preferred embodiments taken in connection with the accompanying drawings in which:
A thermal printer according to embodiments of the disclosure will be described while referring to the accompanying drawings wherein like parts and components are designated by the same reference numerals to avoid duplicating description.
First, an overall configuration of a tape printing device 1 according to first to tenth embodiments will be described while referring to
As shown in
Within the cassette housing portion 8 is also disposed the thermal head 9 (
As shown in
The type of tape is specified by “tape type” and “tape width”. The tape type could be a receptor (non-laminated) tape in which the surface of the print tape is not covered by a protective film, or a laminated tape in which the surface of the print tape is protected by transparent film, or a transfer tape for iron transfers done by using pressure to form letters by applying the heat of an iron. Similarly, the tape width is one of 6 mm, 9 mm, 12 mm, 18 mm, 24 mm, and so on. The energy required for printing differs with the tape type, such that the energy required for printing one dot is approximately 1.3 mJ for receptor tape, approximately 1.1 mJ for laminated tape, or approximately 0.7 mJ for transfer tape. These differences in print energy are due to the higher energy that is necessary for exposing the ink portion on the surface of receptor tape, required by the adhesiveness (abrasion resistance and solidity) of the ink to the tape surface. In addition, transfer tape necessitates primary and secondary transfers, so the necessary energy is made smaller to ensure that there is no reverse transfer due to excess energy (which would cause the processing layer of the tape surface to separate from the ribbon side during the peeling of the ribbon).
In the present embodiment, the signals of the tape-type detection sensors TS1 to TS5 indicate which of the sensor holes are present, as will be describe later. Thus, if the tape type is laminated tape and the tape width is 24 mm, the sensor TS1 sends an on-signal to indicate that the corresponding sensor hole is not detected, the sensor TS2 sends an on-signal to indicate that the corresponding sensor hole is not detected, the sensor TS3 sends an on-signal to indicate that the corresponding sensor hole is not detected, the sensor TS4 sends an off-signal to indicate that the corresponding sensor hole is detected, and the sensor TS5 sends an on-signal to indicate that the corresponding sensor hole is not detected. For the other tape types too, the relationships between the on/off-signals of the tape identification sensors TS1 to TS5 and the presence of the through-holes formed in the tape specification portion 40 are such that an on-signal means that the sensor hole is not detected and an off-signal means that the sensor hole is detected, in a similar manner. Thus, further description thereof is omitted.
As shown in
Next, as shown in
The unused part of the ink ribbon 43 that is wound onto the reel 42 and is drawn out from the reel 42 is laid over the print tape 36, is passed through the aperture portion 52 together with the print tape 36, and is passed between the thermal head 9 and the platen roller 10. The ink ribbon 43 is subsequently peeled off from the print tape 36, reaches the ink ribbon take-up reel 44 that is driven in rotation by the ink ribbon take-up shaft 15, and is wound up by the ink ribbon take-up reel 44.
The double-sided adhesive tape 46 is laid on removable paper and is wound in that state onto the tape spool 47 with the removable paper on the outer side, for storage. The double-sided adhesive tape 46 that is drawn out from the tape spool 47 passes between the tape drive roller 53 and the tape feed roller 11, and the side thereof that is not overlaid by the removable paper is affixed to the print tape 36. A spacer 46A is inserted into both upper and lower edge portions of the double-sided adhesive tape 46.
This ensures that the print tape 36 that was wound onto the tape spool 37 and has been drawn out from the tape spool 37 passes through the aperture portion 52 into which the thermal head 9 of the tape cassette 35 is inserted. The print tape 36 onto which the double-sided adhesive tape 46 has been pasted is subsequently provided in a freely rotatable manner in a lower portion of one side of the tape cassette 35 (the lower left side in
When the tape cassette 35 is mounted in the cassette housing portion 8, the tape specification portion 40 is disposed in a corner portion of the base portion of the main cassette body 35B (the top right corner portion in
Next, a control (electrical) configuration of the tape printing device 1 will be described while referring to
Dot pattern data for displaying each of a large number of characters is stored in the CGROM 24 in correspondence to code data.
Dot pattern data for printing is classified for each of various fonts (such as Gothic or Japanese Mincho fonts), for a large number of characters for printing characters such as alphabetics or symbols, and the corresponding print character sizing and code data for six versions (16, 24, 32, 48, 64, and 96 dot sizes) for each font are stored within the ROM (dot pattern data memory) 25. Graphic pattern data for printing graphic images, including grayscale representation, is also stored therein.
Various programs are stored in the ROM 26, such as a display drive control program that controls an LCDC (LCD controller) 28 in accordance with code data for characters such as alphanumerics that have been input from the keyboard 6, a print drive control program that reads data out of a print buffer 272 and drives the thermal head 9 and the tape feed motor 30, a pulse count determination program that determines the number of pulses corresponding to the amount of energy for forming each print dot, and a drive control program for the heating elements R1 to Rn of the thermal head 9, which will be described later. In addition, various programs necessary for the control of the tape printing device 1 are stored therein. The CPU 21 is designed to perform various calculations based on the various programs stored in the ROM 26.
Furthermore, areas such as a text memory 271, the print buffer 272, a line print dot count memory 273, a total print dot count memory 274, a parameter storage area 275, a tape-type memory 276, and a voltage measurement value memory (voltage memory) 277 are provided in the RAM 27, and document data that has been input from the keyboard 6 is stored in the text memory 271. Data such as dot patterns for printing a plurality of characters and symbols and numbers of application pulses that indicate the amount of energy for forming each dot is stored as dot pattern data in the print buffer 272. The thermal head 9 prints dots in accordance with the dot pattern data stored in the print buffer 272. The print dot count for one line (128 dots in the present embodiment) to be printed by the thermal head 9 is stored in the line print dot count memory 273. The total print dot count from start-up to be printed by the thermal head 9 is stored in the total print dot count memory 274. Various different parameter tables are stored in the parameter storage area 275, as will be described later. The tape types detected by the tape-type detection sensors for the previous time and the current time are stored in the tape-type memory 276. The voltage measurement value detected by the voltage measurement portion 34 for the previous time and the current time are stored in the voltage measurement value memory 277.
The keyboard 6, the thermistor 13, the LCDC 28 having a video RAM 281 for outputting display data to the LCD 7, a drive circuit 29 for driving the thermal head 9, and a drive circuit 31 for driving the tape feed motor 30 are each connected to the input-output interface 23. Thus, when characters or the like have been input by the character keys of the keyboard 6, the text (document data) is sequentially stored in the text memory 271 and also dot patterns corresponding to the characters that have been input through the keyboard 6 are displayed on the LCD 7, based on a dot pattern generation control program and a display drive control program. The thermal head 9 is driven through the drive circuit 29 to print the dot pattern data stored in the print buffer 272, and the tape feed motor 30 implements control through the drive circuit 31 over the feeding of the tape, in synchronization therewith. The thermal head 9 prints characters or the like on the tape, by driving the heating elements R1 to Rn through the drive circuit 29 to selectively generate heat in correspondence to one line of print dots.
A power source 32 supplies the control circuit 20, the drive circuit 29, and the drive circuit 31 with electrical power. The voltage of the power source 32 is measured at predetermined intervals by a voltage measurement portion 34. The power source 32 is connected to a stabilized power source 33 that outputs a constant voltage.
In addition, the power source 32 is connected to the drive circuit 29 of the thermal head 9 and the drive circuit 31 of the tape feed motor 30, and the electrical power of the power source 32 is supplied thereto directly. The stabilized power source 33, on the other hand, is connected to the control circuit 20 and supplies a constant (stabilized) voltage obtained from the electrical power of the power source 32 to the control circuit 20, including the LCD 7. Note that the power source 32 could also be a battery power source or a DC power source from an AC adapter to which a commercial power supply is input, where the AC input is rectified and stepped down to form a DC output.
The voltage measurement portion 34 is connected to the CPU 21 of the control circuit 20 to measure the voltage of the power source 32 and to output the measurement result to the CPU 21.
Next, parameter tables stored in the parameter storage area 275 will be described while referring to
As shown in
Three different ambient temperature ranges are stored beforehand for the ambient temperature 611 of the dot count parameter table 61: “greater than or equal to 30° C.”, “greater than or equal to 20° C. and less than 30° C.”, and “less than 20° C.”. The total amounts 612 corresponding to the ambient temperatures 611 are stored previously, as “250000 dots” for the ambient temperature 611 of “greater than or equal to 30° C.”, “300000 dots” for the ambient temperature 611 of “greater than or equal to 20° C. but less than 30° C.”, and “460000 dots” for the ambient temperature 611 of “less than 20° C.”. Similarly, the discharge amounts 613 corresponding to the ambient temperatures 611 are stored beforehand, as “1800 dots” for the ambient temperature 611 of “greater than or equal to 30° C.”, “2000 dots” for the ambient temperature 611 of “greater than or equal to 20° C. but less than 30° C.”, and “2600 dots” for the ambient temperature 611 of “less than 20° C.”. Note that the total amount 612 and discharge amount 613 corresponding to each ambient temperature 611 are parameters that can be modified to any numerical value to correspond to any change such as a change in the amount of natural thermal radiation of the thermal head 9 caused by a design change in shape of the thermal radiation plate 9A.
As shown in
For the same excess dot count 621, the value of the heat buildup coefficient d increases as the ambient temperature 622 rises, and for the same ambient temperature 622, the value of the heat buildup coefficient d increases as the excess dot count rises. Therefore, in a heat buildup state in which the ambient temperature 622 rises and the excess dot count 621 also rises, the value of the heat buildup coefficient d increases and thus adjustment is performed to shorten an ON time (a duration in which a voltage is applied) and ensure that heat buildup print fattening does not occur.
Note that the heat buildup coefficient d is subjected to such correction both when the temperature is rising (during unsteady-state operation) and when the temperature is saturated (during steady-state operation).
As shown in
As shown in
A tape printing operation to be executed by the tape printing device 1 according to a first embodiment will be described while referring to the flowchart shown in
First, when the power is turned on and the processing of the tape printing device 1 starts, in S1 the CPU 21 obtains the ambient temperature from the thermistor 13. In S3 printing starts in accordance with a direction from a user. In S5 the timer 210 starts counting together with the start of printing. In S7 the CPU 21 detects the tape type of the tape cassette 35 that is installed in the tape printing device 1 based on signals from the tape-type detection sensors, and stores the tape type in the tape-type memory 276.
In S9 the CPU 21 determines the temperature coefficient t, the initial total amount (reference dot count), and the discharge amount, based on the ambient temperature obtained in S1. The temperature coefficient t is calculated from a formula such as t=a/(temperature A/D value)+b (where a and b are fixed values, and the temperature A/D value is an A/D conversion of the ambient temperature), and is used during the determination of the energy to be applied to the heating elements, as will be described later. The total amount and discharge amount corresponding to the ambient temperature are determined in accordance with the dot count parameter table 61 that is stored in the parameter storage area 275. The total amount and the discharge amount are stored in the total print dot count memory 274 of the RAM 27.
In S11 the CPU 21 inputs data for one line of data to be printed, and stores the corresponding dot count for that one line portion in the line print dot count memory 273 that is part of the RAM 27. In S13 the CPU 21 adds the dot count for one line portion, which was stored in the line print dot count memory 273 in S11, to the total amount determined in S9, to calculate the total dot count D. In S15 a value equal to the discharge amount determined in S9 multiplied by the time elapsed since the start of printing is subtracted from the total dot count D to adjust the dot count. Here, the start of printing means a time point at which the user pushed a print-start button of the tape printing device 1. The processing of S13 and S15 calculates the total dot count D by adding the number of dots to be printed from now onward to the total amount determined in S9, then subtracting a value obtained by multiplying the discharge amount determined in S9 by the elapsed time since the start of printing (total dot count=total amount+print dot count−(discharge amount×elapsed time)). In this way, the heat buildup status of the thermal head 9 can be expressed as a number of dots by adding the print dot count then performing adjustment, by converting the amount of thermal radiation into a dot count and subtracting that value from the total dot count. As shown in the flowchart of
In S17 the CPU 21 sets the heat buildup coefficient d, based on an excess dot count and the ambient temperature that was obtained in S1. The excess dot count is the difference between the current total dot count D that was adjusted in S15 and a reference dot count (the initial value of the total amount that was set in S9). The heat buildup coefficient d is determined in accordance with the heat buildup coefficient table 62 stored in the parameter storage area 275. During the first round of processing, the difference between the current total dot count D and the reference dot count is less than 50000, so the heat buildup coefficient d is set to 1 regardless of the ambient temperature.
In S19 the CPU 21 obtains the voltage applied to the thermal head 9 from the voltage measurement portion 34. In S21 the CPU 21 sets the correction coefficient d1 based on the thus-obtained voltage and the tape type obtained in S7. If the tape type is receptor tape and thus the voltage value is 6.0, for example, the correction coefficient d1 is 100%.
In S23 the CPU 21 sets the voltage change coefficient C(V) based on the voltage obtained in S19. The voltage change coefficient C(V) is determined in accordance with the voltage change coefficient table 63 stored in the parameter storage area 275 and is used during the setting of the application energy (pulse width) as will be described later.
In S25 the CPU 21 sets the pulse width (ON time) to be applied to each heating element, by substituting a predetermined value into an application control coefficient C. A predetermined fixed value is substituted into the application control coefficient C. Each time a predetermined time period elapses, values corresponding to the ambient temperature, voltage, and heat buildup status are subtracted from the predetermined fixed value, using a calculation equation that will be described later, and energy is applied to the heating elements (electricity is passed therethrough) until the application control coefficient C reaches zero. In the present embodiment, a value of 55400 is substituted into the application control coefficient C, for example.
In S27 the CPU 21 determines whether the application control coefficient C has become less than zero. If the application control coefficient C is greater than or equal to 0 (S27: NO), in S29 drive pulses are applied to turn the heating elements on. In S31 the CPU 21 determines whether 250 microseconds have elapsed. The application of the drive pulses continues (S29) until 250 microseconds have elapsed (S31: NO).
When 250 microseconds have elapsed (S31: YES), in S33 the CPU 21 re-calculates the application control coefficient C to determine whether the application of drive pulses should continue, and determines the amount of energy that should be applied subsequently. The re-evaluation of the application energy is in accordance with a formula C←C−C (V)×t×d. The voltage change coefficient C(V) increases as the voltage increases, the temperature coefficient t increases as the ambient temperature increases, and the value of the heat buildup coefficient d increases as the excess dot count and ambient temperature increase. Thus the value derived by multiplying all these elements becomes larger as the ambient temperature increases and heat buildup of the thermal head 9 progresses because of continued printing, and the value also increases as the application time of the main pulses becomes longer. Since the value obtained by subtracting the multiplication result from the application control coefficient C is taken as the new value of C, the result is that the application control coefficient C will become smaller when heat buildup progresses.
In other words, since the application control coefficient C approaches zero faster, the ON time of each heating element is shortened, and the occurrence of print fattening can be avoided. If the voltage is low, the correction coefficient d1 is close to 100% and thus the heat buildup control is greater and print fattening is avoided. However, if the voltage is high, the correction coefficient d1 becomes less than 100% and thus there is no blurring due to excessive heat buildup control. In addition, since the correction coefficient d1 decreases slowly even when the voltage becomes higher with receptor tape that requires a high print energy, the heat buildup control can be increased and the pulse width shortened for tapes in which heat buildup can easily progress.
Subsequently, the process returns to S27, and the CPU 21 again determines whether the application control coefficient C after the calculation of S33 has become less than zero. When the application control coefficient C becomes less than zero (S27: YES), in S35 the heating elements are turned off for a predetermined time to cool the thermal head 9. In S37 the CPU 21 then determines whether printing is continued and, if printing is continued (S37: YES), the process returns to S11 and the next one line of data is input. If printing is not continued (S37: NO), the processing ends.
As described above, since the tape printing device 1 of the present embodiment uses the correction coefficient d1 that is determined by the currently installed tape type and the voltage applied to the thermal head 9, heat buildup information can be obtained as appropriate even when printing on tapes that have different print energy requirements. In addition, the heat buildup status can be determined accurately and print fattening avoided, even when printing under conditions of long ON times, such as under the low voltage condition.
When an alkaline battery is used as a power source and if the heat buildup is calculated without considering a voltage difference of the power sources, printing is often performed at a comparatively low voltage and thus the ON time tends to be longer. This would increases an amount of heat buildup more than when a different type of power source such as an AC adapter is used, making it more likely that print fattening will occur. However, such problem can be avoided according to the tape printing device 1 of the present embodiment.
A correction coefficient table used in a tape printing operation according to a second embodiment will be described while referring to
As shown in
The tape printing operation of the tape printing device 1 according to the second embodiment will be described while referring to the flowcharts of
When the power is turned on and the processing of the tape printing device 1 starts, in S101 the CPU 21 obtains the ambient temperature from the thermistor 13. In S103 printing starts in accordance with a direction from the user. In S105 the timer 210 starts counting together with the start of printing. In S107 the CPU 21 detects the tape type of the tape cassette 35 that is installed in the tape printing device 1, based on signals from the tape-type detection sensors.
In S109 the CPU 21 determines the temperature coefficient t, the initial total amount (reference dot count), and the discharge amount, based on the ambient temperature obtained in S101. The temperature coefficient t is calculated from a formula such as t=a/(temperature A/D value)+b (where a and b are fixed values, and the temperature A/D value is an A/D conversion of the ambient temperature), and is used during the determination of the energy to be applied to the heating elements, as will be described later. The total amount and discharge amount corresponding to the ambient temperature are determined in accordance with the dot count parameter table 61 (
In S111 the CPU 21 inputs data for one line of data to be printed, and stores the corresponding dot count for the one line portion in the line print dot count memory 273 that is part of the RAM 27. In S113 the CPU 21 adds the dot count for one line portion, which was stored in the line print dot count memory 273 in S111, to the total amount determined in S109, to calculate the total dot count D. In S115 a value equal to the discharge amount determined in S109 multiplied by the time elapsed since the start of printing is subtracted from the total dot count D calculated in S113, to adjust the dot count. The processing of S113 and S115 calculates the total dot count D by adding the number of dots to be printed from now onward to the total amount determined in S109, then subtracting a value obtained by multiplying the discharge amount determined in S109 by the elapsed time since the start of printing (total dot count=total amount+print dot count−(discharge amount×elapsed time)). Thus the heat buildup status of the thermal head 9 can be expressed as a number of dots by adding the print dot count then performing adjustment by converting the amount of thermal radiation into a dot count and subtracting the value from the print dot count.
In S117 the CPU 21 sets the heat buildup coefficient d, based on an excess dot count, which is the difference between the current total dot count D that was adjusted in S115 and a reference dot count (the initial value of the total amount that was set in S109), and the ambient temperature that was obtained in S101. The heat buildup coefficient d is determined in accordance with the heat buildup coefficient table 62 (
In S119 the CPU 21 obtains the voltage to be applied to the thermal head 9 from the voltage measurement portion 34. In S123 the CPU 21 sets the voltage change coefficient C(V) based on the thus-obtained voltage. The voltage change coefficient C(V) is determined in accordance with the voltage change coefficient table 63 stored in the parameter storage area 275. The voltage change coefficient C(V) is used during the main pulse application processing and the sub-pulse application processing as will be described later.
In S125 the CPU 21 executes the main pulse application processing that sets the main pulses to be applied to the heating elements. Details of the main pulse application processing will be given later, while referring to
The main pulse application processing to be executed in S125 of
In S202 the CPU 21 clears a loop counter L. The loop counter L is designed to count the number of executions for the re-evaluation of energy application every 250 microseconds, as will be described later. In S203 the CPU 21 determines whether the application control coefficient C has become less than zero. If the application control coefficient C is greater than or equal to 0 (S203: NO), in S205 drive pulses are applied to turn the heating elements on. In S207 the CPU 21 determines whether 250 microseconds have elapsed. The application of the drive pulses continues (S205) until 250 microseconds have elapsed (S207: NO).
When 250 microseconds have elapsed (S207; YES), in S208 the CPU 21 adds 1 to the loop counter L. In S209 the CPU 21 re-calculates the application control coefficient C to determine whether the application of drive pulses should continue, and determines the amount of energy that should be applied subsequently. The re-evaluation of the application energy is in accordance with a formula C←C−C (V)×t×d. The voltage change coefficient C(V) increases as the voltage increases, the temperature coefficient t increases as the ambient temperature increases, and the value of the heat buildup coefficient d increases as the excess dot count and ambient temperature increases. Thus a value that is derived from all of these elements multiplied together will increase when the ambient temperature rises and the thermal head 9 stores heat as the printing continues. Since the value obtained by subtracting the multiplication result from the application control coefficient C is taken as the new value of C, the application control coefficient C decreases faster when the heat buildup proceeds. When the application control coefficient C becomes less than zero in S203, the main pulse application processing ends and the process proceeds to the sub-pulse application processing. Hence the ON time can be shortened when heat buildup is progressing and thus the occurrence of print fattening can be avoided.
Subsequently, the process returns to S203, and the CPU 21 again determines whether the application control coefficient C after the calculation of S209 has become less than zero. When the application control coefficient C becomes less than zero (S203: YES), the process returns to the main routine for heat buildup control shown in
The sub-pulse application processing to be executed in S127 of
In S302 the CPU 21 reads the value of the loop counter L and sets the correction coefficient M from the correction coefficient table 164. For example, if the applied energy re-evaluation processing every 250 microseconds has been performed three times by the main pulse application processing, the correction coefficient M is 1.03.
In S303 the CPU 21 determines whether the application control coefficient C has become less than zero. If the application control coefficient C is greater than or equal to 0 (S303: NO), in S305 drive pulses are applied to turn the heating elements on. In S307 the CPU 21 determines whether 250 microseconds have elapsed. The application of the drive pulses continues (S305) until 250 microseconds have elapsed (S307: NO).
When 250 microseconds have elapsed (S307: YES), in S309 the CPU 21 re-calculates the application control coefficient C to determine whether the application of drive pulses should continue, and determines the amount of energy that should be applied subsequently. The re-evaluation of the application energy is in accordance with a formula C←C−C(V)×t×d×M(n). The voltage change coefficient C(V) increases as the voltage increases, the temperature coefficient t increases as the ambient temperature increases, the value of the heat buildup coefficient d increases as the excess dot count and ambient temperature increase, and the value of the correction coefficient M increases as the width of the main pulses increases. Thus the value derived by multiplying all these elements becomes larger as the ambient temperature increases and heat buildup of the thermal head 9 progresses because of continued printing, and the value also increases as the application time of the main pulses becomes longer. Since the value obtained by subtracting the multiplication result from the application control coefficient C is taken as the new value of C, the result is that the application control coefficient C will become smaller when heat buildup progresses and also the ON time of the main pulses is longer. When the application control coefficient C becomes less than zero in S303, the application of sub-pulses to the heating elements ends. This means that the ON time becomes shorter and the occurrence of print fattening can be avoided when heat buildup progresses and also when the ON time of the main pulses is long enough that auxiliary heating is not necessary.
Subsequently, the process returns to S303, and the CPU 21 again determines whether the application control coefficient C after the calculation of S309 has become less than zero. When the application control coefficient C becomes less than zero (S303: YES), in S311 the heating elements are turned off for a predetermined time to cool the thermal head 9. The flow returns to the main routine for heat buildup control shown in
As described above, the tape printing device 1 of the present embodiment corrects the value of the heat buildup coefficient d for the sub-pulses by the correction coefficient M that becomes greater as the pulse width of the main pulses becomes larger, to determine the width of the sub-pulses and thus implement auxiliary heating of the heating elements. Accordingly, when auxiliary heating to avoid print blurring is unnecessary as the heat buildup progresses and ON time of the main pulses is sufficiently long, the width of the sub-pulses can be shortened to reduce the ON time thereof. Thus, print fattening due to excessive auxiliary heating under history control can be avoided, even when printing a pattern in which all of the heating elements are used intermittently, such as a bar code.
The thermal printer disclosed in Japanese patent-application publication No. 7-108701 adjusts only the width of the main pulses and does not adjust the width of the sub-pulses. This is because the sub-pulses are shorter than the main pulses and thus it is considered the sub-pulses will not be affected much by the heat buildup. However, with print patterns such as bar codes where all the heating elements are used intermittently, a history control is performed by using sub-pulses to provide auxiliary heating for dots that were not printed in the previous line, and thus print fattening is more likely to occur than in ordinary printing.
A tape printing operation of the tape printing device 1 according to a third embodiment will be described while referring to the flowcharts of
When the power is turned on and the processing of the tape printing device 1 starts, in S401 the CPU 21 obtains the ambient temperature from the thermistor 13. In S403 printing starts in accordance with a direction from the user. In S405 the timer 210 starts counting together with the start of printing.
In S409 the CPU 21 determines the temperature coefficient t, the initial total amount (reference dot count), and the discharge amount, based on the ambient temperature obtained in S401. The temperature coefficient t is calculated from a formula such as t=a/(temperature A/D value)+b (where a and b are fixed values, and the temperature A/D value is an A/D conversion of the ambient temperature), and is used during the determination of the energy to be applied to the heating elements, as will be described later. Values that correspond to the ambient temperature are substituted into the total amount and discharge amount, in accordance with the dot count parameter table 61 that is stored in the parameter storage area 275. The total amount and the discharge amount are stored in the total print dot count memory 274 of the RAM 27.
In S411 the CPU 21 inputs data for one line of data to be printed, and stores the corresponding dot count for the one line portion in the line print dot count memory 273 that is part of the RAM 27. In S413 the CPU 21 adds the dot count for one line portion, which was stored in the line print dot count memory 273 in S411, to the total amount determined in S409, to calculate the total dot count D. In S415 a value equal to the discharge amount determined in S409 multiplied by the time elapsed since the start of printing is subtracted from the total dot count D calculated in S413, to adjust the dot count. The processing of S413 and S415 calculates the total dot count D by adding the number of dots to be printed from now onward to the total amount determined in S409, then subtracting a value obtained by multiplying the discharge amount determined in S409 by the elapsed time since the start of printing (total dot count=total amount+print dot count−(discharge amount×elapsed time)). Thus the heat buildup status of the thermal head 9 can be expressed as a number of dots by adding the print dot count then performing adjustment by converting the amount of thermal radiation into a dot count and subtracting the value from the print dot count.
In S417 the CPU 21 sets the heat buildup coefficient d based on an excess dot count and the ambient temperature that was obtained in S406. The excess dot count is the difference between the current total dot count D that was adjusted in S415 and a reference dot count (the initial value of the total amount that was set in S409). The heat buildup coefficient d is determined in accordance with the heat buildup coefficient table 62 (
In S425 the CPU 21 executes a pulse application processing that sets pulses to be applied to the heating elements. Details of the pulse application processing will be given later while referring to
The pulse application processing executed in S425 of
In S503 the CPU 21 determines whether the application control coefficient C has become less than zero. If the application control coefficient C is greater than or equal to 0 (S503: NO), in S505 drive pulses are applied to turn the heating elements on. In S507 the CPU 21 determines whether 250 microseconds have elapsed. The application of the drive pulses continues (S505) until 250 microseconds have elapsed (S507: NO).
When 250 microseconds have elapsed (S507: YES), in S509 the CPU 21 obtains the voltage applied to the thermal head 9 from the voltage measurement portion 34 as an AD value. In S510 the CPU 21 determines whether the voltage was obtained for the first time. If it is not the first time (that is, the second time or more) that the voltage was obtained (S510: NO), the processing directly goes to S512. If the voltage was obtained for the first time (S510: YES), in S511 the CPU 21 sets the voltage change coefficient C(V) based on the voltage obtained in S509. The voltage change coefficient C(V) is determined in accordance with the voltage change coefficient table 63 stored in the parameter storage area 275.
In S512 the CPU 21 compares the voltage measurement value obtained in S509 (the current voltage measurement value) with the previous voltage measurement value (AD value) stored in the voltage measurement value memory 277, to determine whether the both values are equal. If the current voltage measurement value is equal to the previous voltage value (S512: YES), the CPU 21 uses the previous voltage change coefficient C(V) without any change so the process proceeds to S517.
If the current voltage measurement value is not equal to the previous voltage measurement value (S512; NO), in S513 the CPU 21 determines whether the current voltage measurement value is greater than the previous voltage measurement value. If the current voltage measurement value is greater than the previous voltage measurement value (S513: YES), in S515 the CPU 21 increments the voltage value (AD value) of the current voltage change coefficient C(V) by 1 and substitutes C(V+1) into C(V). If the current voltage measurement value is less than the previous voltage measurement value (S513: NO), in S519 the CPU 21 decrements the voltage value (AD value) of the current voltage change coefficient C(V) by 1 and substitutes C(V−1) into C(V). In S517 the CPU 21 re-calculates the application control coefficient C to determine whether the application of drive pulses should continue and determines the amount of energy that should be applied subsequently. The re-evaluation of the application energy is in accordance with a formula C←C−C(V)×t×d. Then, the process returns to S503.
The above processing is repeated to determine the application pulse width every 250 microseconds and, when the application control coefficient C becomes less than zero (S503: YES), the heating elements are turned off for a predetermined time (S521) to cool the thermal head 9. The flow returns to the main routine for heat buildup control shown in
As described above, the tape printing device 1 of the present embodiment reads out the voltage value after the voltage application to the heating elements has started, and determines the voltage change coefficient C(V) that is a parameter for evaluating the application energy based on the voltage value. Since the no-load voltage which is likely to be comparatively high in the pre-printing state is not used when determining the parameter, the occurrence of blurring due to insufficient application energy can be prevented because the ON time is shortened by a high voltage value. In addition, the voltage AD value that was obtained by the voltage measurement portion 34 is not utilized directly. Instead, the application pulse width is determined by comparing the previous voltage value with the current voltage value. A voltage AD value that is the same as the previous one is used if the previous and current voltage values are the same. A voltage AD value incremented by 1 is used if the current voltage value is higher than the previous voltage value. A voltage AD value decremented by 1 is used if the current voltage value is lower than the previous voltage value. Accordingly, the application control coefficient C(V) can be set continuously or linearly for the control of the application pulse width. In other words, it is unnecessary to read the voltage a plurality of times and to calculate an average value thereof, in order to avoid noise in the read-out voltage.
In addition, under the unstable control, there is a large difference in the voltage between a loaded condition (in which the heating elements are powered) and a no-load condition (in which the heating elements are not powered). Therefore, if the voltage is read before the heating elements are powered (no-load condition), the read voltage will be high and the pulse width is determined based on the high voltage, which shortens the ON time. As a result, the supplied energy will be insufficient, leading to print blurring. In the present embodiment, however, the voltage is read after the heating elements are powered (loaded condition), the read voltage will be appropriate and the pulse width is determined based on the appropriate voltage. Thus, the supplied energy will be appropriate, leading to high print quality.
If a voltage is read out successively as in the thermal printer disclosed in Japanese patent-application publication No. 8-300713, it takes time to convert voltage analog values into digital values (A/D conversion) for a plurality of voltage values. It takes even more time if the voltage is read out a plurality of times and an average value is calculated in consideration of noise. There is also a limit in the number of read-out times when the read-out has to be performed in a short time period.
Next, a correction coefficient table used in a fourth embodiment will be described while referring to
A tape printing operation according to the fourth embodiment will be described while referring to the flowchart shown in
When the power is turned on and the processing of the tape printing device 1 starts, in S1001 the CPU 21 sets an initial value for the previous tape type and stores the value in the tape-type memory 276. The tape type detected in S1004 will eventually be substituted as the previous tape type in each repeat of the routine, as will be described later, but since this is initialization processing immediately after power-on, laminated tape is set as the initial value in S1001, because the laminated tape is considered to be the most frequently used type of tape.
In S1002 printing starts in accordance with a direction from the user. In S1003 the timer 210 starts counting together with the start of printing. In S1004 the CPU 21 detects the type of tape within the tape cassette 35 that is installed in the tape printing device 1 based on signals from the tape-type detection sensors, and stores the tape type in the tape-type memory 276.
In S1006 the CPU 21 obtains the ambient temperature from the thermistor 13. In S1007 the CPU 21 determines a temperature coefficient t, the initial total amount (reference dot count), and the discharge amount, based on the thus-obtained ambient temperature. The temperature coefficient t is calculated from a formula such as t=a/(temperature A/D value)+b (where a and b are fixed values, and the temperature A/D value is an A/D conversion of the ambient temperature), and is used during the determination of the energy to be applied to the heating elements, as will be described later. Values that correspond to the ambient temperature are substituted into the total amount and discharge amount, in accordance with the dot count parameter table 61 that is stored in the parameter storage area 275. The total amount and the discharge amount are stored in the total print dot count memory 274 of the RAM 27.
In S1008 the CPU 21 adds the number of dots to be printed from now onward to the total amount determined in S1007, to calculate a total dot count D. Since the dot count for one line portion is stored in the line print dot count memory 273 of the RAM 27, the value is used. In S1009 the CPU 21 subtracts a value equal to the discharge amount determined in S1007 multiplied by the time elapsed since the start of printing from the total dot count D calculated in S1008, to adjust the dot count. The processing of S100B and S1009 obtains the total dot count D by adding the number of dots to be printed from now onward to the total amount determined in S1007, then subtracting a value obtained by multiplying the discharge amount determined in S1007 by the elapsed time since the start of printing (total dot count=total amount+print dot count−(discharge amount×elapsed time)). Thus the heat buildup status of the thermal head 9 can be expressed as a number of dots by adding the print dot count then performing adjustment by converting the amount of thermal radiation into a dot count and subtracting the value from the total dot count.
In S1010 the CPU 21 determines whether the tape type that has been detected this time (the current time) is the same as the previous tape type that was stored in the tape-type memory 276, If the current tape type is the same as the previous tape type (S1010. YES), there is no change to the required print energy and thus no correction is necessary and the process proceeds to S1012.
In S1011 if the current tape type differs from the previous tape type (S1010: NO), the CPU 21 corrects the total dot count D that was adjusted in S1009, in accordance with the correction coefficient table 264. The correction is done with a formula D=D×dc. If the previous tape type was laminated tape and the current tape type is non-laminated (receptor) tape, for example, the correction coefficient dc is 0.9, and the total dot count after the correction is 0.9 times the total dot count D obtained in S1009. The correction coefficient dc depends on the energy requirement of the tape type, so that if the change is from a tape type with a large energy requirement to a tape type with a small energy requirement, the coefficient will become larger. On the other hand, if the change is from a tape type with a small energy requirement to a tape type with a large energy requirement, the coefficient is smaller. Since the change of tape type in this example is from a laminated tape that is a type of tape with a small energy requirement to a receptor tape that is a type of tape with a large energy requirement. Therefore, the total dot count D which is heat buildup information becomes smaller, and thus print blurring due to excessive heat buildup control can be prevented from occurring.
In S1012 the CPU 21 sets the heat buildup coefficient d, based on an excess dot count and the ambient temperature that was obtained in S1006. The excess dot count is the difference between the current total dot count D that was corrected in S1011 and a reference dot count (the initial value of the total amount that was set in S1007). The heat buildup coefficient d is determined in accordance with the heat buildup coefficient table 62 stored in the parameter storage area 275. During the first round of processing, the difference between the current total dot count D and the reference dot count is less than 50000, so the heat buildup coefficient d is set to 1 regardless of the ambient temperature.
In S1015 the CPU 21 detects the voltage, and in S1016 sets the voltage change coefficient C(V) based on the thus-detected voltage. The determination of the voltage change coefficient C(V) is based on the voltage change coefficient table 63 stored in the parameter storage area 275. The voltage change coefficient C(V) is used when setting the energy to be applied, as will be described later.
In S1017 the CPU 21 sets the pulse width (ON time) to be applied to each heating element, by substituting a predetermined value into an application control coefficient C. The value that is substituted into the application control coefficient C is a predetermined fixed value. Each time a predetermined time period elapses, values corresponding to the ambient temperature, voltage, and heat buildup status are subtracted from the predetermined fixed value, using a calculation equation that will be described later, and energy is applied to the heating elements (electricity is passed therethrough) until the application control coefficient C reaches zero. In the present embodiment, a value of 55400 is substituted into the application control coefficient C, for example.
In S1018 the CPU 21 determines whether the application control coefficient C has become less than zero. If the application control coefficient C is greater than or equal to zero (S1018: NO), in S1019 drive pulses are applied to turn the heating elements on. In S1020 the CPU 21 determines whether 250 microseconds have elapsed. The application of the drive pulses continues (S1019) until 250 microseconds have elapsed (S1020: NO). When 250 microseconds have elapsed (S1020: YES), in S1021 the CPU 21 re-calculates the application control coefficient C to determine whether the application of drive pulses should continue, and determines the amount of energy that should be applied subsequently. The re-evaluation of the application energy is in accordance with a formula C←C−C(V)×t×d. The voltage change coefficient C(V) increases as the voltage increases, the temperature coefficient t increases as the ambient temperature increases, and the value of the heat buildup coefficient d increases as the excess dot count and ambient temperature increases. Thus a value that is derived from all of these elements multiplied together will increase when the ambient temperature rises and the thermal head 9 stores heat as the printing continues. Since the value obtained by subtracting the multiplication result from the application control coefficient C is taken as the new value of C, the application control coefficient C decreases faster when the heat buildup proceeds. In other words, since the application control coefficient C approaches zero faster, the ON time of each heating element is shortened, and the occurrence of print fattening can be avoided.
Subsequently, the process returns to S1018, and the CPU 21 again determines whether the application control coefficient C after the calculation of S1021 has become less than zero. When the application control coefficient C becomes less than zero (S1018: YES), in S1022 the heating elements are turned off for a predetermined time to cool the thermal head 9. In S1023 the CPU 21 substitutes the current tape type into the previous tape type to prepare for the next round of the processing routine. In S1024 the CPU 21 determines whether printing is continued and the process returns to S1002 if printing is continued (S1024: YES) or ends the processing if printing is not continued (S1024: NO).
In the tape printing device 1 according to the fourth embodiment described above, the previously detected tape type is stored, and the CPU 21 determines whether the tape type that is detected the current time is the same. If the tape type is different from the previous tape type, the CPU 21 corrects the total dot count and reflects the tape-type change in the heat buildup information, so that the magnitude of the heat buildup is reflected appropriately by the magnitude of the print energy corresponding to the tape type. Thus the CPU 21 can execute heat buildup control which enables an appropriate maintenance of print quality even when the tape type has been changed.
The tape printing operation according to a fifth embodiment will be described while referring to
As shown in
A tape printing operation according to the fifth embodiment will be described while referring to the flowchart shown in
When the power is turned on and the processing of the tape printing device 1 starts, in S11 the CPU 21 sets an initial value in a previous tape-type constant db and stores the value in the tape-type memory 276. The previous tape-type constant db is substituted for the constant set in the previous processing in which the setting is based on the tape type that is detected in S1104, as will be described later. However, since the processing in S1101 is the initialization processing immediately after power-on, the constant 1.0 is read out from the tape-type constant table 65 and substituted as the initial value to correspond to laminated tape, which is considered to be the most frequently used tape type.
In S1102 printing starts in accordance with a direction from the user. In S1103 a timer is started together with the start of printing. In S1104 the CPU 21 detects the type of tape of the tape cassette 35 that is installed in the tape printing device 1 based on signals from the tape-type detection sensors.
In S1105 the CPU 21 substitutes a constant corresponding to the currently installed tape type detected in S1104, into a current tape-type constant dp. If non-laminated tape has been detected, for example, a value of 0.9 is substituted in accordance with the tape-type constant table 65.
In S1106 the CPU 21 obtains the ambient temperature from the thermistor 13. In S1107 the CPU 21 determines the temperature coefficient t, the initial total amount (reference dot count), and the discharge amount, based on the thus-obtained ambient temperature. The temperature coefficient t is calculated from a formula such as t=a/(temperature A/D value)+b (where a and b are fixed values, and the temperature A/D value is an A/D conversion of the ambient temperature), and is used during the determination of the energy to be applied to the heating elements, as will be described later. Values that correspond to the ambient temperature are substituted into the total amount and discharge amount, in accordance with the dot count parameter table 61 that is stored in the parameter storage area 275. The total amount and the discharge amount are stored in the total print dot count memory 274 of the RAM 27.
In S1108 the CPU 21 adds the dot count for one line portion to be printed from now onward to the total amount determined in S1107, to calculate the total dot count D. Since the dot count for one line portion is stored in the line print dot count memory 273 of the RAM 27, that value is used. In S1109 a value equal to the discharge amount determined in S1107 multiplied by the time elapsed since the start of printing is subtracted from the total dot count D calculated in S1108, to adjust the dot count. The processing of S1108 and S1109 calculates the total dot count D by adding the number of dots to be printed from now onward to the total amount determined in S1107, then subtracting a value obtained by multiplying the discharge amount determined in S1107 by the elapsed time since the start of printing (total dot count=total amount+print dot count−(discharge amount×elapsed time)). Thus the heat buildup status of the thermal head 9 can be expressed as a number of dots by adding the print dot count then performing adjustment by converting the amount of thermal radiation into a dot count and subtracting the value from the print dot count.
In S1111 the CPU 21 corrects the total dot count D that was adjusted in S1109, based on the tape-type constant db that indicates the previous tape type and a current tape-type constant dp that indicates the current tape type. The correction is done with a formula D=D×dp/db. If the previous tape-type constant db is 1.0 (laminated tape) and the current tape-type constant dp is 0.9 (receptor tape), for example, the total dot count after the correction is 0.9 times the total dot count D obtained in S1109. The tape-type constant depends on the energy requirement of the tape type, so that the configuration is such that the constant decreases as the energy requirement of the tape type increases. Since the change of tape type in this example is from a laminated tape that is a type of tape with a small energy requirement to a receptor tape that is a type of tape with a large energy requirement, therefore, the value of the total dot count D that is heat buildup information is smaller, and thus print blurring due to excessive heat buildup control can be prevented from occurring. If the current tape-type constant is the same as the previous tape-type constant, no correction of the total dot count D is done so that the value dp/db becomes 1, enabling correction of the total dot count with a simple configuration without a need to determine whether the previous tape type and the current tape type are the same.
In S1112 the CPU 21 sets the heat buildup coefficient d based on the difference between the current total dot count D that was corrected in S1111 and a reference dot count (the initial value of the total amount that was set in S1107) and the ambient temperature. The heat buildup coefficient d is determined in accordance with the heat buildup coefficient table 62 stored in the parameter storage area 275. During the first round of processing, the difference between the current total dot count D and the reference dot count is less than 50000, so the heat buildup coefficient d is set to 1 regardless of the ambient temperature.
In S1115 the CPU 21 detects the voltage, and in S1116 sets the voltage change coefficient C(V) based on the thus-detected voltage. The determination of the voltage change coefficient C(V) is based on the voltage change coefficient table 63 stored in the parameter storage area 275. The voltage change coefficient C(V) is used when setting the energy to be applied to the heating elements, as will be described later.
In S1117 the CPU 21 sets the pulse width (ON time) to be applied to each heating element by substituting a predetermined value into the application control coefficient C. The value that is substituted into the application control coefficient C is a predetermined fixed value. Each time a predetermined time period elapses, values corresponding to the ambient temperature, voltage, and heat buildup status are subtracted from the predetermined fixed value, using a calculation equation that will be described later, and energy is applied to the heating elements (electricity is passed therethrough) until the application control coefficient C reaches zero. In the present embodiment, a value of 55400 is substituted into the application control coefficient C, for example.
In S1118 the CPU 21 determines whether the application control coefficient C has become less than zero. If the application control coefficient C is greater than or equal to zero (S1118: NO), in S1119 drive pulses are applied to turn the heating elements on. In S1120 the CPU 21 determines whether 250 microseconds have elapsed. The application of the drive pulses continues (Slll9) until 250 microseconds have elapsed (S1120: NO). When 250 microseconds have elapsed (S1120: YES), in S1121 the CPU 21 re-calculates the application control coefficient C and determines the amount of energy that should be applied subsequently. The re-evaluation of the application energy is in accordance with a formula C←C−C(V)×t×d. The voltage change coefficient C(V) increases as the voltage increases, the temperature coefficient t increases as the ambient temperature increases, and the value of the heat buildup coefficient d increases as the excess dot count and ambient temperature increases. Thus a value that is derived from all of these elements multiplied together will increase when the ambient temperature rises and the thermal head 9 stores heat as the printing continues. Since the value obtained by subtracting the multiplication result from the application control coefficient C is taken as the new value of C, the application control coefficient C decreases faster when the heat buildup proceeds. In other words, since the application control coefficient C approaches zero faster, the ON time of each heating element is shortened, and the occurrence of print fattening can be avoided.
Subsequently, the process returns to S1118, and the CPU 21 again determines whether the application control coefficient C after the calculation of S1121 has become less than zero. When the application control coefficient C becomes less than zero (S1118: YES), in S1122 the heating elements are turned off for a predetermined time to cool the thermal head 9. In S1123 the CPU 21 substitutes the current tape-type constant dp into the previous tape-type constant db in order to prepare for the next round of the processing routine. In S1124 the CPU 21 determines whether printing is continued and the process returns to S1102 if printing is continued (S1124: YES) or ends the processing if printing is not continued (S1124: NO).
With the tape printing device 1 of the fifth embodiment, a constant corresponding to the tape type is used in the correction of the total dot count, as described above, so that the CPU 21 can execute heat buildup control in which the magnitude of the heat buildup is reflected appropriately by the magnitude of the print energy corresponding to the tape type. Since a constant corresponding to the tape type is used, it is not necessary to determine whether the previous tape type and the current tape type are different.
Next, the tape printing operation according to a sixth embodiment will be described while referring to
As shown in
A tape printing operation according to the sixth embodiment will be described while referring to the flowchart shown in
In S1202 printing starts in accordance with a direction from the user. In S1203 the count of a timer is started together with the start of printing. In S1204 the CPU 21 detects the type of tape within the tape cassette 35 that is installed in the tape printing device 1 based on signals from the tape-type detection sensors, and stores the tape type in the tape-type memory 276.
In S1206 the CPU 21 obtains the ambient temperature from the thermistor 13. In S1207 the CPU 21 determines the temperature coefficient t, the initial total amount (reference dot count), and the discharge amount, based on the thus-obtained ambient temperature. The temperature coefficient t is calculated from a formula such as t=a/(temperature A/D value)+b (where a and b are fixed values, and the temperature A/D value is an A/D conversion of the ambient temperature), and is used during the determination of the energy to be applied to the heating elements, as will be described later. Values that correspond to the ambient temperature are substituted into the total amount and discharge amount, in accordance with the dot count parameter table 61 that is stored in the parameter storage area 275. The total amount and the discharge amount are stored in the total print dot count memory 274 of the RAM 27.
In S1208 the CPU 21 adds the dot count for one line portion to be printed from now onward to the total amount determined in S1207, to calculate the total dot count D. Since the dot count for one line portion is stored in the line print dot count memory 273 of the RAM 27, that value is used. In S1209 a value equal to the discharge amount determined in S1207 multiplied by the time elapsed since the start of printing is subtracted from the total dot count D calculated in S1208, to adjust the dot count. The processing of S1208 and S1209 calculates the total dot count D by adding the number of dots to be printed from now onward to the total amount determined in S1207, then subtracting a value obtained by multiplying the discharge amount determined in S1207 by the elapsed time since the start of printing (total dot count=total amount+print dot count−(discharge amount×elapsed time)). Thus the heat buildup status of the thermal head 9 can be expressed as a number of dots by adding the print dot count then performing adjustment by converting the amount of thermal radiation into a dot count and subtracting the value from the print dot count.
In S1210 the CPU 21 determines whether the tape type that has been detected this time (the current time) is the same as the previous tape type that was stored in the tape-type memory 276. If the current tape type is the same as the previous tape type (S1210: YES), there is no change to the required print energy and thus no correction is necessary and the process proceeds to S1212.
If the current tape type differs from the previous tape type (S1210: NO), the CPU 21 corrects the total dot count that was adjusted in S1209 in accordance with the dot count correction value table 66. The correction is done with a formula D=D+de. For example, if the previous tape type is laminated tape and the current tape type is receptor (non-laminated) tape and the excess dot count is within the range of 50000 to 99999, the correction value de is −5000 and the total dot count after the correction is obtained by subtracting 5000 from the value obtained by S1209. The dot count correction value de depends on the energy requirement of the tape type. Thus the dot count correction value de is a positive value if the change is from a tape type with a large energy requirement to a tape type with a small energy requirement or a negative value if the change is from a tape type with a small energy requirement to a tape type with a large energy requirement. Further, the absolute value of the dot count correction value de increases as the excess dot count becomes larger (as heat buildup proceeds). Since the change of tape type in this example is from a laminated tape that is a type of tape with a small energy requirement to a receptor tape that is a type of tape with a large energy requirement, the value of the total dot count D that is heat buildup information is smaller, and thus print blurring due to excessive heat buildup control can be prevented from occurring.
In S1212 the CPU 21 sets the heat buildup coefficient d based on an excess dot count and the ambient temperature that was obtained in S1206. The excess dot count is the difference between the current total dot count D that was corrected in S1211 and a reference dot count (the initial value of the total amount that was set in S1207). The heat buildup coefficient d is determined in accordance with the heat buildup coefficient table 62 stored in the parameter storage area 275. During the first round of processing, the difference between the current total dot count D and the reference dot count is less than 50000, so the heat buildup coefficient d is set to 1 regardless of the ambient temperature.
In S1215 the CPU 21 detects the voltage, and in S1216 sets the voltage change coefficient C(V) based on the thus-detected voltage. The determination of the voltage change coefficient C(V) is based on the voltage change coefficient table 63 stored in the parameter storage area 275. The voltage change coefficient C(V) is used when setting the energy to be applied, as will be described later.
In S1217 the CPU 21 sets the pulse width (ON time) to be applied to each heating element by substituting a predetermined value into the application control coefficient C. The value that is substituted into the application control coefficient C is a predetermined fixed value. Each time a predetermined time period elapses, values corresponding to the ambient temperature, voltage, and heat buildup status are subtracted from the predetermined fixed value, using a calculation equation that will be described later, and energy is applied to the heating elements (electricity is passed therethrough) until the application control coefficient C reaches zero. In the present embodiment, a value of 55400 is substituted into the application control coefficient C, for example.
In S1218 the CPU 21 determines whether the application control coefficient C has become less than zero. If the application control coefficient C is greater than or equal to zero (S1218: NO), in S1219 drive pulses are applied to turn the heating elements on. In S1220 the CPU 21 determines whether 250 microseconds have elapsed. The application of the drive pulses continues (S1219) until 250 microseconds have elapsed. When 250 microseconds have elapsed (S1220: YES), in S1221 the CPU 21 re-calculates the application control coefficient to determine whether the application of drive pulses should continue, and determines the amount of energy that should be applied subsequently. The re-evaluation of the application energy is in accordance with a formula C←C−C(V)×t×d. The voltage change coefficient C(V) increases as the voltage increases, the temperature coefficient t increases as the ambient temperature increases, and the value of the heat buildup coefficient d increases as the excess dot count and ambient temperature increases. Thus a value that is derived from all of these elements multiplied together will increase when the ambient temperature rises and the thermal head 9 stores heat as the printing continues. Since the value obtained by subtracting the multiplication result from the application control coefficient C is taken as the new value of C, the application control coefficient C decreases faster when the heat buildup proceeds. In other words, since the application control coefficient C approaches zero faster, the ON time of each heating element is shortened, and the occurrence of print fattening can be avoided.
Subsequently, the process returns to S1218, and the CPU 21 again determines whether the application control coefficient C after the calculation of S1221 has become less than zero. When the application control coefficient C becomes less than zero (S1218: YES), in S1222 the heating elements are turned off for a predetermined time to cool the thermal head 9. In S1223 the CPU 21 substitutes the current tape type into the previous tape type in order to prepare for the next round of the processing routine. In the above-mentioned example, laminated tape is substituted by non-laminated tape. In the next execution of the routine, the previous tape type is processed as non-laminated tape. In S1224 the CPU 21 determines whether printing is continued and the process returns to S1202 if printing is continued (S1224: YES) or ends the processing if printing is not continued (S1224: NO).
As described above, since the tape printing device 1 according to the sixth embodiment stores the previous tape type and, if the current tape type differs from the previous tape type, the CPU 21 performs correction by adding or subtracting the dot count correction value de to or from the total dot count, which reflects the heat buildup information. Thus the magnitude of the heat buildup is reflected appropriately by the magnitude of the print energy corresponding to the tape type. Thus the CPU 21 can execute heat buildup control which enables an appropriate maintenance of print quality even when the tape type has been changed.
Next, the tape printing operation according to a seventh embodiment will be described while referring to
As shown in
As shown in
In S1302 printing starts in accordance with a direction from the user. In S1303 the count of a timer is started together with the start of printing. In S1304 the CPU 21 detects the type of tape of the tape cassette 35 that is installed in the tape printing device 1 based on signals from the tape-type detection sensors.
In S1305 the CPU 21 substitutes the dot correction constant dr corresponding to the currently installed tape type, which was detected in S1304, into the current correction constant dg. If non-laminated tape was detected, for example, the excess dot count is still below 50000 so a value of 0 is substituted into the current correction constant dg, in accordance with the dot count correction constant table 67.
In S1306 the CPU 21 obtains the ambient temperature from the thermistor 13. In S1307 the CPU 21 determines the temperature coefficient t, the initial total amount (reference dot count), and the discharge amount, based on the thus-obtained ambient temperature. The temperature coefficient t is calculated from a formula such as t=a/(temperature A/D value)+b (where a and b are fixed values, and the temperature A/D value is an A/D conversion of the ambient temperature), and is used during the determination of the energy to be applied to the heating elements, as will be described later. Values that correspond to the ambient temperature are substituted into the total amount and discharge amount, in accordance with the dot count parameter table 61 that is stored in the parameter storage area 275. The total amount and the discharge amount are stored in the total print dot count memory 274 of the RAM 27.
In S1308 the CPU 21 adds the dot count for one line portion to be printed from now onward to the total amount determined in S1307, to calculate the total dot count D. Since the dot count for one line portion is stored in the line print dot count memory 273 of the RAM 27, that value is used. In S1309 a value equal to the discharge amount determined in S1307 multiplied by the time elapsed since the start of printing is subtracted from the total dot count D calculated in S1308, to adjust the dot count. The processing of S1308 and S1309 calculates the total dot count D by adding the number of dots to be printed from now onward to the total amount determined in S1307, then subtracting a value obtained by multiplying the discharge amount determined in S1307 by the elapsed time since the start of printing (total dot count=total amount+print dot count−(discharge amount×elapsed time)). Thus the heat buildup status of the thermal head 9 can be expressed as a number of dots by adding the print dot count then performing adjustment by converting the amount of thermal radiation into a dot count and subtracting the value from the print dot count.
In S1311 the CPU 21 corrects the total dot count D that was adjusted in S1309, based on the previous tape-type constant df and the current tape-type constant dg. The correction is done with a formula D=D+df−dg. For example, if the excess dot counts are in a range between 50000 and 99999 and the previous tape-type constant df is 10000 (laminated tape) and the current tape-type constant dg is 15000 (receptor tape), the total dot count after the correction is the total dot count D obtained in S1309 minus 5000. The correction constant dr depends on the energy requirement of the tape type, and its value is smaller for tape types with small energy requirements. Since the change of tape type in this example is from a laminated tape that is a type of tape with a small energy requirement to a receptor tape that is a type of tape with a large energy requirement, the value of the total dot count D that is heat buildup information becomes smaller, and thus print blurring due to excessive heat buildup control can be prevented from occurring. If the current tape-type constant dg is the same as the previous tape-type constant df, no correction of the total dot count is performed because a difference between the tape-type constants (df−dg) becomes zero. Accordingly, the total dot count can be corrected with a simple configuration, without determining whether the previous tape type and the current tape type are the same.
In S1312 the CPU 21 sets the heat buildup coefficient d, based on the difference between the current total dot count D that was corrected in S1311 and a reference dot count (the initial value of the total amount that was set in S1307) and the ambient temperature. The heat buildup coefficient d is determined in accordance with the beat buildup coefficient table 62 stored in the parameter storage area 275. During the first round of processing, the difference between the current total dot count D and the reference dot count is less than 50000, so the heat buildup coefficient d is set to 1 regardless of the ambient temperature.
In S1315 the CPU 21 detects the voltage, and in S1316 sets the voltage change coefficient C(V) based on the thus-detected voltage. The determination of the voltage change coefficient C(V) is based on the voltage change coefficient table 63 stored in the parameter storage area 275. The voltage change coefficient C(V) is used when setting the energy to be applied, as will be described later.
In S1317 the CPU 21 sets the pulse width (ON time) applied to each heating element by substituting a predetermined value into the application control coefficient C. The value that is substituted into the application control coefficient C is a predetermined fixed value. Each time a predetermined time period elapses, values corresponding to the ambient temperature, voltage, and heat buildup status are subtracted from the predetermined fixed value, using a calculation equation that will be described later, and energy is applied to the heating elements (electricity is passed therethrough) until the application control coefficient C reaches zero. In the present embodiment, a value of 55400 is substituted into the application control coefficient C, for example.
In S1318 the CPU 21 determines whether the application control coefficient C has become less than zero. If the application control coefficient C is greater than or equal to zero (S1318: NO), in S1319 drive pulses are applied to turn the heating elements on. In S1320 the CPU 21 determines whether 250 microseconds have elapsed. The application of the drive pulses continues (Sl319) until 250 microseconds have elapsed (s1320; NO). When 250 microseconds have elapsed (S1320: YES), in S1321 the CPU 21 re-calculates the application control coefficient C to determine whether the application of drive pulses should continue, and determines the amount of energy that should be applied subsequently. The re-evaluation of the application energy is in accordance with a formula C←C−C(V)×t×d. The voltage change coefficient C(V) increases as the voltage increases, the temperature coefficient t increases as the ambient temperature increases, and the value of the heat buildup coefficient d increases as the excess dot count and ambient temperature increases. Thus a value that is derived from all of these elements multiplied together will increase when the ambient temperature rises and the thermal head 9 stores heat as the printing continues. Since the value obtained by subtracting the multiplication result from the application control coefficient C is taken as the new value of C, the application control coefficient C decreases faster when the heat buildup proceeds. In other words, since the application control coefficient C approaches zero faster, the ON time of each heating element is shortened, and the occurrence of print fattening can be avoided.
Subsequently, the process returns to S1318, and the CPU 21 again determines whether the application control coefficient C after the calculation of S1321 has become less than zero. When the application control coefficient C becomes less than zero (S1318: YES), in S1322 the heating elements are turned off for a predetermined time to cool the thermal head 9. In S1323 the current tape-type constant dg is substituted into the previous tape-type constant df in order to prepare for the next execution of the processing routine. In S1324 the CPU 21 determines whether printing is continued and the process returns to S1302 if printing is continued (S1324: YES) or ends the processing if printing is not continued (S1324: NO).
As described above, with the tape printing device 1 according to the seventh embodiment, a constant corresponding to the tape type is used in the correction of the heat buildup coefficient. Accordingly, the magnitude of the heat buildup is reflected appropriately by the magnitude of the print energy corresponding to the tape type. Thus the CPU 21 can execute heat buildup control which maintains an appropriate print quality even when the tape type has been changed.
Next, the tape printing operation according to an eighth embodiment will be described while referring to
As shown in
In S1402 printing starts in accordance with a direction from the user. In S1403 the count of a timer is started together with the start of printing. In S1404 the CPU 21 detects the type of tape within the tape cassette 35 that is installed in the tape printing device 1 based on signals from the tape-type detection sensors, and stores the tape type in the tape-type memory 276.
In S1406 the CPU 21 obtains the ambient temperature from the thermistor 13. In S1407 the CPU 21 determines the temperature coefficient t, the initial total amount (reference dot count), and the discharge amount, based on the thus-obtained ambient temperature. The temperature coefficient t is calculated from a formula such as t=a/(temperature A/D value)+b (where a and b are fixed values, and the temperature A/D value is an A/D conversion of the ambient temperature), and is used during the determination of the energy to be applied to the heating elements, as will be described later. Values that correspond to the ambient temperature are substituted into the total amount and discharge amount, in accordance with the dot count parameter table 61 that is stored in the parameter storage area 275. The total amount and the discharge amount are stored in the total print dot count memory 274 of the RAM 27.
In S1408 the CPU 21 adds the dot count for one line portion to be printed from now onward to the total amount determined in S1407, to calculate the total dot count D. Since the dot count for one line portion is stored in the line print dot count memory 273 of the RAM 27, that value is used. In S1409 a value equal to the discharge amount determined in S1407 multiplied by the time elapsed since the start of printing is subtracted from the total dot count D calculated in S1408, to adjust the dot count. The processing of S1408 and S1409 calculates the total dot count D by adding the number of dots to be printed from now onward to the total amount determined in S1407, then subtracting a value obtained by multiplying the discharge amount determined in S1407 by the elapsed time since the start of printing (total dot count=total amount+print dot count−(discharge amount×elapsed time)). Thus the heat buildup status of the thermal head 9 can be expressed as a number of dots by adding the print dot count then performing adjustment by converting the amount of thermal radiation into a dot count and subtracting the value from the total dot count.
In S1412 the CPU 21 sets the heat buildup coefficient d based on the difference between the current total dot count D and the reference dot count and the ambient temperature. The heat buildup coefficient d is determined in accordance with the heat buildup coefficient table 62 stored in the parameter storage area 275.
In S1413 the CPU 21 determines whether the tape type that has been detected this time (the current time) is the same as the previous tape type that was stored in the tape-type memory 276. If the current tape type is the same as the previous tape type (S1413; YES), there is no change to the required print energy and thus no correction is necessary and the process proceeds to S1415.
If the current tape type differs from the previous tape type (S1413: NO), in S1414 the CPU 21 corrects the heat buildup coefficient d that was adjusted in S1412, in accordance with the correction coefficient table 64. The correction is done with a formula d=d×dc. If the previous tape type was laminated tape and the current tape type is receptor tape, for example, the correction coefficient dc becomes 0.9 so that the heat buildup coefficient d after the correction is 0.9 times the value that was obtained in S1412. The correction coefficient dc depends on the energy requirement of the tape type, so that if the change is from a tape type with a large energy requirement to a tape type with a small energy requirement, the coefficient will become larger. On the other hand, if the change is from a tape type with a small energy requirement to a tape type with a large energy requirement, the coefficient will become smaller. Since the change of tape type in this example is from a laminated tape that is a type of tape with a small energy requirement to a receptor tape that is a type of tape with a large energy requirement, the value of the heat buildup coefficient d that is used in the calculations of energy to apply (described later) becomes smaller. Thus, print blurring due to excessive heat buildup control can be prevented from occurring.
In S1415 the CPU 21 detects the voltage, and in S1416 sets the voltage change coefficient C(V) based on the thus-detected voltage. The determination of the voltage change coefficient C(V) is based on the voltage change coefficient table 63 stored in the parameter storage area 275. The voltage change coefficient C(V) is used when setting the energy to be applied, as will be described later.
In S1417 the CPU 21 sets the pulse width (ON time) applied to each heating element by substituting a predetermined value into the application control coefficient C. The value that is substituted into the application control coefficient C is a predetermined fixed value. Each time a predetermined time period elapses, values corresponding to the ambient temperature, voltage, and heat buildup status are subtracted from the predetermined fixed value, using a calculation equation that will be described later, and energy is applied to the heating elements (electricity is passed therethrough) until the application control coefficient C reaches zero. In the present embodiment, a value of 55400 is substituted into the application control coefficient C, for example.
In S1418 the CPU 21 determines whether the application control coefficient C has become less than zero. If the application control coefficient C is greater than or equal to zero (S1418: NO), in S1419 drive pulses are applied to turn the heating elements on. In S1420 the CPU 21 determines whether 250 microseconds have elapsed. The application of the drive pulses continues (S1419) until 250 microseconds have elapsed (S1420: NO). When 250 microseconds have elapsed (S1420: YES), in S1421 the CPU 21 re-calculates the application control coefficient C to determine whether the application of drive pulses should continue, and determines the amount of energy that should be applied subsequently. The re-evaluation of the application energy is in accordance with a formula C←C−C(V)×t×d. The voltage change coefficient C(V) increases as the voltage increases, the temperature coefficient t increases as the ambient temperature increases, and the value of the heat buildup coefficient d increases as the excess dot count and ambient temperature increases. Thus a value that is derived from all of these elements multiplied together will increase when the ambient temperature rises and the thermal head 9 stores heat as the printing continues. Since the value obtained by subtracting the multiplication result from the application control coefficient C is taken as the new value of C, the application control coefficient C decreases faster when the heat buildup proceeds. In other words, since the application control coefficient C approaches zero faster, the ON time of each heating element is shortened, and the occurrence of print fattening can be avoided.
Subsequently, the process returns to S1418, and the CPU 21 again determines whether the application control coefficient C after the calculation of S1421 has become less than zero. When the application control coefficient C becomes less than zero (S1418: YES), in S1422 the heating elements are turned off for a predetermined time to cool the thermal head 9. In S1423 the CPU 21 substitutes the current tape type into the previous tape type in order to prepare for the next round of the processing routine. In S1424 the CPU 21 determines whether printing is continued and the process returns to S1402 if printing is continued (S1424: YES) or ends the processing if printing is not continued (S1424: NO).
As described above, since the tape printing device 1 according to the eighth embodiment stores the previous tape type and, if the current tape type differs from the previous tape type, the CPU 21 corrects the heat buildup coefficient which reflects the heat buildup information. Thus the magnitude of the heat buildup is reflected appropriately by the magnitude of the print energy corresponding to the tape type. Thus the CPU 21 can execute heat buildup control which maintains an appropriate print quality even when the tape type has been changed.
Next, the tape printing operation according to a ninth embodiment will be described while referring to
As shown in
In S1502 printing starts in accordance with a direction from the user. In S1503 the count of a timer is started together with the start of printing. In S1504 the CPU 21 detects the type of the tape by signals from the tape-type detection sensors.
In S1505 the CPU 21 substitutes a constant corresponding to the currently installed tape type, detected in S1504, into the current tape-type constant dp. If non-laminated tape has been detected, for example, a value of 0.9 is substituted in accordance with the tape-type constant table 65.
In S1506 the CPU 21 obtains the ambient temperature from the thermistor 13. In S1507 the CPU 21 determines the temperature coefficient t, the initial total amount (reference dot count), and the discharge amount, based on the thus-obtained ambient temperature. The temperature coefficient t is calculated from a formula such as t=a/(temperature A/D value)+b (where a and b are fixed values, and the temperature A/D value is an A/D conversion of the ambient temperature), and is used during the determination of the energy to be applied to the heating elements, as will be described later. Values corresponding to the ambient temperature are substituted into the total amount and discharge amount, in accordance with the dot count parameter table 61 that is stored in the parameter storage area 275.
In S1508 the CPU 21 adds the dot count for one line portion to be printed from now onward to the total amount determined in S1507, to calculate the total dot count D. In S1509 a value equal to the discharge amount determined in S1507 multiplied by the time elapsed since the start of printing is subtracted from the total dot count D calculated in S1508, to adjust the dot count. The processing of S1508 and S1509 calculates the total dot count D by adding the number of dots to be printed from now onward to the total amount determined in S1507, then subtracting a value obtained by multiplying the discharge amount determined in S1507 by the elapsed time since the start of printing (total dot count=total amount+print dot count−(discharge amount×elapsed time)).
In S1512 the CPU 21 sets the heat buildup coefficient d based on the difference between the current total dot count D and the reference dot count and the ambient temperature. The heat buildup coefficient d is determined in accordance with the heat buildup coefficient table 62 that is stored in the parameter storage area 275.
In S1514 the CPU 21 corrects the heat buildup coefficient d obtained in S1512 based on the previous tape-type constant db that indicates the previous tape type and the current tape-type constant dp that indicates the current tape type. The correction is done with a formula d=d×dp /db. If d=1.0, db=1.0, and dp=0.9, for example, the corrected value of the heat buildup coefficient d becomes 0.9.
In S1515 the CPU 21 detects the voltage, and in S1516 sets the voltage change coefficient C(V) based on the thus-detected voltage. The determination of the voltage change coefficient C(V) is based on the voltage change coefficient table 63 stored in the parameter storage area 275. The voltage change coefficient C(V) is used when setting the energy to be applied, as will be described later.
In S1517 the CPU 21 sets the pulse width (ON time) applied to each heating element by substituting a predetermined value into the application control coefficient C. The value that is substituted into the application control coefficient C is a predetermined fixed value. Each time a predetermined time period elapses, values corresponding to the ambient temperature, voltage, and heat buildup status are subtracted from the predetermined fixed value, using a calculation equation that will be described later, and energy is applied to the heating elements (electricity is passed therethrough) until the application control coefficient C reaches zero. In the present embodiment, a value of 55400 is substituted into the application control coefficient C, for example.
In S1518 the CPU 21 determines whether the application control coefficient C has become less than zero. If the application control coefficient C is greater than or equal to zero (S1518: NO), in S1519 drive pulses are applied to turn the heating elements on. In S1520 the CPU 21 determines whether 250 microseconds have elapsed. The application of the drive pulses continues (S1519) until 250 microseconds have elapsed (S1520: NO). When 250 microseconds have elapsed (S1520: YES), in S1521 the CPU 21 re-calculates the application control coefficient C to determine whether the application of drive pulses should continue, and determines the amount of energy that should be applied subsequently. The re-evaluation of the application energy is in accordance with a formula C←C−C(V)×t×d. The voltage change coefficient C(V) increases as the voltage increases, the temperature coefficient t increases as the ambient temperature increases, and the value of the heat buildup coefficient d increases as the excess dot count and ambient temperature increases. Thus a value that is derived from all of these elements multiplied together will increase when the ambient temperature rises and the thermal head 9 stores heat as the printing continues. Since the value obtained by subtracting the multiplication result from the application control coefficient C is taken as the new value of C, the application control coefficient C decreases faster when the heat buildup proceeds. In other words, since the application control coefficient C approaches zero faster, the ON time of each heating element is shortened, and the occurrence of print fattening can be avoided.
Subsequently, the process returns to S1518, and the CPU 21 again determines whether the application control coefficient C after the calculation of S1521 has become less than zero. When the application control coefficient C becomes less than zero (S1518: YES), in S1522 the heating elements are turned off for a predetermined time to cool the thermal head 9. In S1523 the CPU 21 substitutes the current tape-type constant dp into the previous tape-type constant is db in order to prepare for the next round of the processing routine. In S1524 the CPU 21 determines whether printing is continued and the process returns to S1502 if printing is continued (S1524: YES) or ends the processing if printing is not continued (S1524: NO).
As described above, with the tape printing device 1 according to the ninth embodiment, a constant corresponding to the tape type is used in the correction of the heat buildup coefficient. Accordingly, the magnitude of the heat buildup is reflected appropriately by the magnitude of the print energy corresponding to the tape type. Thus the CPU 21 can execute heat buildup control which maintains an appropriate print quality even when the tape type has been changed.
Next, a tape printing operation according to a tenth embodiment will be described while referring to
When the power is turned on and the processing of the tape printing device 1 starts, in S1601 the CPU 21 sets an initial value for the previous tape type and stores that value in the tape-type memory 276. The tape type detected in S1604 will eventually be substituted as the previous tape type in each repeat of the routine, as will be described later, but since this is initialization processing immediately after power-on, laminated tape is set as the initial value in S1601, because the laminated tape is considered to be the most frequently used type of tape.
In S1602 printing starts in accordance with a direction from the user. In S1603 a timer is started together with the start of printing. In S1604 the CPU 21 detects the type of tape within the tape cassette 35 that is installed in the tape printing device 1 based on signals from the tape-type detection sensors, and stores the tape type in the tape-type memory 276.
In S1606 the CPU 21 obtains the ambient temperature from the thermistor 13. In S1607 the CPU 21 determines the temperature coefficient t, the initial total amount (reference dot count), and the discharge amount, based on the thus-obtained ambient temperature. The temperature coefficient t is calculated from a formula such as t=a/(temperature A/D value)+b (where a and b are fixed values, and the temperature A/D value is an A/D conversion of the ambient temperature), and is used during the determination of the energy to be applied to the heating elements, as will be described later. Values that correspond to the ambient temperature are substituted into the total amount and discharge amount, in accordance with the dot count parameter table 61 that is stored in the parameter storage area 275. The total amount and the discharge amount are stored in the total print dot count memory 274 of the RAM 27.
In S1608 the CPU 21 adds the dot count for one line portion to be printed from now onward to the total amount determined in S1607, to calculate the total dot count D. Since the dot count for one line portion is stored in the line print dot count memory 273 of the RAM 27, that value is used. In S1609 a value equal to the discharge amount determined in S1607 multiplied by the time elapsed since the start of printing is subtracted from the total dot count D calculated in S1608, to adjust the dot count. The processing of S1608 and S1609 obtains the total dot count D by adding the number of dots to be printed from now onward to the total amount determined in S1607, then subtracting a value obtained by multiplying the discharge amount determined in S1607 by the elapsed time since the start of printing (total dot count=total amount+print dot count−(discharge amount×elapsed time)). Thus the heat buildup status of the thermal head 9 can be expressed as a number of dots by adding the print dot count then performing adjustment by converting the amount of thermal radiation into a dot count and subtracting the value from the total dot count.
In S1610 the CPU 21 determines whether the tape type that has been detected this time (the current time) is the same as the previous tape type that was stored in the tape-type memory 276. If the current tape type is the same as the previous tape type (S1610: YES), there is no change to the required print energy and thus no correction is necessary and the process proceeds to S1612.
If the current tape type differs from the previous tape type (S1610: NO), in S1611 the CPU 21 substitutes zero into the total dot count D that was adjusted in S1609, to reset the total dot count D. Since this processing causes a reset of the total dot count D that is the heat buildup information, print blurring due to excessive heat buildup control can be prevented from occurring. If the current tape type is the same as the previous tape type, no correction is performed and thus excessive control can be avoided.
In S1612 the CPU 21 sets the heat buildup coefficient d, based on difference between the current total dot count D that was corrected in S1611 and the reference dot count (the initial value of the total amount that was set in S1607) and the ambient temperature. The heat buildup coefficient d is determined in accordance with the heat buildup coefficient table 62 stored in the parameter storage area 275. Since the current total dot count D has been reset to zero in S1611, the excess dot count is also zero which is less than 50000. Thus heat buildup coefficient d is set to 1 regardless of the ambient temperature.
In S1615 the CPU 21 detects the voltage, and in S1616 sets the voltage change coefficient C(V) based on the thus-detected voltage. The determination of the voltage change coefficient C(V) is based on the voltage change coefficient table 63 stored in the parameter storage area 275. The voltage change coefficient C(V) is used when setting the energy to be applied, as will be described later.
In S1617 the CPU 21 sets the pulse width (ON time) to be applied to each heating element by substituting a predetermined value into the application control coefficient C. The value that is substituted into the application control coefficient C is a predetermined fixed value. Each time a predetermined time period elapses, values corresponding to the ambient temperature, voltage, and heat buildup status are subtracted from the predetermined fixed value, using a calculation equation that will be described later, and energy is applied to the heating elements (electricity is passed therethrough) until the application control coefficient C reaches zero. In the present embodiment, a value of 55400 is substituted into the application control coefficient C, for example.
In S1618 the CPU 21 determines whether the application control coefficient C has become less than zero. If the application control coefficient C is greater than or equal to zero (S1618: NO), in S1619 drive pulses are applied to turn the heating elements on. In S1620 the CPU 21 determines whether 250 microseconds have elapsed. The application of the drive pulses continues (S1619) until 250 microseconds have elapsed (S1620: NO). When 250 microseconds have elapsed (S1620: YES), in S1621 the CPU 21 re-calculates the application control coefficient C to determine whether the application of drive pulses should continue, and determines the amount of energy that should be applied subsequently. The re-evaluation of the application energy is in accordance with a formula C←C−C(V)×t×d. The voltage change coefficient C(V) increases as the voltage increases, the temperature coefficient t increases as the ambient temperature increases, and the value of the heat buildup coefficient d increases as the excess dot count and ambient temperature increases. Thus a value that is derived from all of these elements multiplied together will increase when the ambient temperature rises and the thermal head 9 stores heat as the printing continues. Since the value obtained by subtracting the multiplication result from the application control coefficient C is taken as the new value of C, the application control coefficient C decreases faster when the heat buildup proceeds. In other words, since the application control coefficient C approaches zero faster, the ON time of each heating element is shortened, and the occurrence of print fattening can be avoided.
The processing then returns to S1618. If the application control coefficient C becomes less than zero (S1618: YES), in S1622 the CPU 21 turns the heating elements off for a predetermined time to cool the thermal head 9. In S1623 the CPU 21 substitutes the current tape type into the previous tape type in order to prepare for the next round of the processing routine. In S1624 the CPU 21 determines whether printing is continued. The flow returns to S1602 if printing is continued (S1624: YES) or ends the processing if printing is not continued (S1624: NO).
As described above, the tape printing device 1 according to the tenth embodiment stores the previous tape type and, if the current tape type differs from the previous tape type, resets the heat buildup information so that the total dot count D becomes zero. If the heat buildup information is not reset when the current tape type has been changed from the previous tape type, the heat buildup information stored at that point may not be appropriate anymore, and the print energy may become inappropriate (that is, excessively small or excessively large). With the present embodiment, however, it is possible to avoid the problem that the print energy becomes inappropriate after the tape type has been changed. Thus, an appropriate print quality can be maintained even after the tape type has been changed.
The thermal printer disclosed in Japanese patent-application publication No. 2001-191574 uses an accumulated print dot count to control an amount of the heat buildup, and adjusts the accumulated print dot count depending on the tape type. This is because the amount of the heat buildup is small after continuous printing with a tape type having a small print energy requirement, and is large after continuous printing with a tape type having a large print energy requirement. Since the adjustment is performed only at power-on, this conventional thermal printer cannot cope with a change in tape types that require different print energy, resulting in deterioration in the print quality such as print blurring or fattening. Such problem can be avoided with the tape printing device 1 according to the above-described fourth to tenth embodiments.
While the disclosure has been described in detail with reference to the specific embodiment thereof, it would be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the disclosure.
For example, in the above-described embodiments, the tape printing device 1 has the keyboard 6, where text that has been input from the keyboard 6 and is printed on tape. However, the tape printing device 1 may be connected to an external device such as a personal computer and the tape printing device 1 may receive print data from the external device and prints the data.
Further, in the above-described embodiments, the ambient temperature is measured by the thermistor 13 installed in the tape printing device 1. However, external measurement means may be provided outside the tape printing device 1, and the external measurement means may measure the ambient temperature adjacent to the tape printing device 1 and send the ambient temperature information to the tape printing device 1.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-097358 | Mar 2004 | JP | national |
| 2004-097360 | Mar 2004 | JP | national |
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| 2004-097364 | Mar 2004 | JP | national |
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