JP2001191574A - Thermal recording device - Google Patents

Abstract

(57) [Summary] [Problem] To properly adjust the energy applied to each heating element based on the heat storage state of each heating element generated due to a past printing operation, thereby reducing the size and density of the dot pattern. Provided is a thermal recording apparatus that can be made uniform. SOLUTION: When energy is applied to each heating element according to an energy level stored in a table 21 of a ROM 5 in a multi-valued manner, a heat storage level generated in each heating element is added over a plurality of recordings. And store it in the heat storage memory 9,
In this manner, the number of drive pulses corresponding to the energy level to be applied to each heating element is reduced and applied to each heating element based on the sum of the heat storage levels of each heating element stored in the heat storage memory 9. Thus, the state of heat storage in each heating element is accurately grasped, appropriate energy is applied to each heating element, and the size and density of the dot pattern recorded by each heating element are made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of converting energy applied to a plurality of heating elements formed on a thermal head into a plurality of levels and applying energy corresponding to the energy level of the heating elements. With this, characters composed of dot patterns while realizing multiple density levels,
The present invention relates to a thermal recording apparatus for recording figures and the like on a recording medium, and in particular, to appropriately correct the energy applied to each heating element based on the heat storage state of each heating element generated due to a past recording operation. Accordingly, the present invention relates to a thermal recording apparatus capable of making the size and density of a dot pattern uniform.

[0002]

2. Description of the Related Art Conventionally, various types of thermal recording apparatuses for recording characters, figures, and the like on a recording medium via a thermal head having a plurality of heating elements formed thereon have been proposed.
For example, Japanese Patent Publication No. Sho 6
Japanese Patent Application Laid-Open No. 4-2076 discloses a heating state at the time of printing immediately before a heating resistor to be heated currently, a heating state at the time of printing immediately before and below a heating resistor adjacent to a heating resistor to be heated at present, and A thermal recording method is described in which the number of pulses applied to a heating resistor to be heated at present is selected and printing is performed in consideration of heating information of the heating resistor to be heated next time.

According to such a thermal recording method, recording can be performed at a uniform density in consideration of the heat storage history of the heating resistor that has just generated heat with respect to the heating resistor that is to generate heat at present.

[0004]

However, even with the above-mentioned conventional thermal recording method, it is possible to control the heat storage of the heating resistor to a certain extent to make the density uniform, but in this recording method, Only whether or not the immediately preceding heating resistor has been printed with respect to the heating resistor to be heated, ie, only the on / off state of the heating resistor, is considered.

Here, the state of heat storage in the heating resistor in the thermal head and its peripheral portion is determined by the cumulative occurrence of heat generated by the ON / OFF state of the heating resistor in the past. As described above, when only the on / off state of the heating resistor is considered and the heating energy with which the heating resistor is turned on is not considered, the heat storage state in the heating resistor and its peripheral portion is considered. Cannot be determined exactly.

Therefore, in the above-mentioned conventional thermal recording method, although the on / off state of the heating resistor immediately before is considered, the heat storage state accumulated so far is not considered at all. Even if it is possible to record at a uniform density, it is still insufficient.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and it is desirable to appropriately adjust the energy applied to each heating element based on the heat storage state of each heating element generated due to a past recording operation. It is an object of the present invention to provide a thermal recording apparatus capable of making the dot pattern size and density uniform by correcting the dot pattern.

[0008]

According to a first aspect of the present invention, there is provided a thermal recording apparatus, comprising: a thermal head having a plurality of heating elements formed therein; A first storage unit that stores a multi-level level and stores the heat storage state generated in each heating element when energy is applied to each heating element according to the level stored in the first storage unit. Second storage means for adding and storing over the recording, and energy correction means for correcting energy to be applied to each heating element based on the heat storage state of each heating element stored in the second storage means. And energy applying means for applying the energy corrected through the energy correcting means to each heating element.

In the thermal recording apparatus of the first aspect, the first
When energy is applied to each heating element in accordance with the level stored in a multi-valued manner in the storage means, the heat storage state generated in each heating element is added over a plurality of recordings and stored in the second storage means. The energy to be applied to each heating element is corrected through the correction means based on the heat storage state of each heating element stored in the second storage means, and the corrected energy is applied to the energy applying means. Since the heat is applied to each of the heat generating elements, it is possible to accurately grasp the heat storage state of each of the heat elements and apply appropriate energy to each of the heat elements. As a result, the size and density of the dot pattern recorded by each heating element can be made uniform.

A thermal recording apparatus according to a second aspect is the thermal recording apparatus according to the first aspect, wherein
The storage means stores the level of each energy as the number of drive pulses applied to the heating element, and the energy correction means corrects the number of drive pulses. According to the thermal recording apparatus of the second aspect, since the level of energy applied to each heating element can be corrected by the number of drive pulses, the correction process is simplified and can be easily performed. It becomes possible.

Further, the thermal recording apparatus according to claim 3 is the thermal recording apparatus according to claim 2, wherein
The heat storage state of each heating element stored in the storage means is divided into a plurality of heat storage levels, and the energy correction means changes the correction amount of the drive pulse corresponding to each of the heat storage levels. In the thermal recording apparatus according to the third aspect, the heat storage state of each heating element is divided into a plurality of heat storage levels, and the correction amount of the drive pulse may be changed according to each heat storage level. The change process can be simplified and performed quickly and easily.

According to a fourth aspect of the present invention, in the thermal recording apparatus according to the second or third aspect, the second storage means comprises a heat storage counter, and a counter value of the heat storage counter and the driving pulse. Calculating means for calculating the number of reductions of the drive pulse corresponding to the counter value of the heat storage counter based on a predetermined relationship corresponding to the number of reductions of the heat storage counter, wherein the energy correction means calculates the number of reductions calculated by the calculation means The number of drive pulses is reduced according to In the thermal recording apparatus according to the fourth aspect, the counter value of the heat storage counter is made to correspond to the number of reductions of the drive pulse in advance, and the number of reductions of the drive pulse is calculated based on the correspondence relationship. The number of drive pulses to reduce the number of drive pulses to drive the heating elements, so that the number of drive pulses corresponding to the counter value can be obtained without the need for a large-capacity memory to facilitate heat storage control of the heating elements. It can be carried out.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a thermal recording apparatus according to the present invention will be described in detail with reference to the drawings based on first and second embodiments in which the present invention is applied to a tape printing apparatus. First, a schematic configuration of the tape printer will be described with reference to FIG. FIG. 1 is a block diagram showing a control configuration of the tape printer.

In FIG. 1, the tape printing apparatus is configured with a control device 1 as a core. The control device 1 includes a CPU 2 for controlling each device, and a data bus 11
Input / output interface 10, CGR connected via
OM3, ROM4, 5 and RAM6.

The CGROM 3 stores dot pattern data for display in association with code data for each of a large number of characters.

A dot pattern data memory (ROM) 4 stores dot pattern data for printing for each of a large number of characters for printing characters such as alphabetic characters and symbols.
(Mincho style, etc.), and 6 types (1
6, 24, 32, 48, 64, and 96 dot sizes) are stored in association with the code data. In addition, graphic pattern data for printing a graphic image is also stored.

The ROM 5 reads out a display drive control program for controlling the LCDC 15 in accordance with the code data of characters such as characters and numerals input from the keyboard 12, data of the print buffer 8, and reads out the thermal head 17 and the tape. A printing drive control program for driving the feed motor 19 and various other programs necessary for controlling the tape printing apparatus are stored. And CPU2
Performs various calculations based on various programs stored in the ROM 5.

Further, in the ROM 5, as shown in FIG.
A plurality of heating elements (2
The energy applied to the 24 heating elements is formed into eight levels, and a table 21 is stored in which each energy level is associated with the number of driving pulses.

Here, the table 21 will be described with reference to FIG. Each dot data constituting the dot pattern data and the graphic pattern data is accompanied by the data of each energy level corresponding to its density level, and is applied to the heating element corresponding to each energy level. The number of drive pulses is set. Specifically, when driving dot data of energy level 1, two driving pulses are applied to the heating element, and when driving dot data of energy level 2, four driving pulses are applied. Is done. Similarly, a driving pulse of 6 pulses is applied to dot data of energy level 3, an driving pulse of 8 pulses is applied to dot data of energy level 4, a driving pulse of 12 pulses is applied to dot data of energy level 5, and a driving pulse of energy level 6 is used. The dot data has 20 driving pulses, the energy level 7 dot data has 32 driving pulses, and the energy level 8 dot data has 63 driving pulses.
Each is supported.

The table 21 shows that the effect of heat storage in the heating element is small when the number of driving pulses applied to the heating element is small, and that the heating element is not affected when the number of driving pulses is large. In consideration of the great effect of heat storage, each energy level is divided into three heat storage levels, and a relationship in which each of the divided heat storage levels is associated with the number of reductions in the drive pulse is stored. Specifically, the heat storage level 1 corresponds to energy levels 1 to 5 in which the number of drive pulse pulses is 2, 4, 6, 8, and 12, and the heat storage level 2 is that the number of drive pulse pulses is 20, 32. And the heat storage level 3 corresponds to the energy level 8 where the number of drive pulses is 63.

The heat storage level is obtained from the table 21 based on the number of driving pulses applied to the heating element each time the dot pattern is printed a plurality of times by each heating element of the thermal head 17 each time printing is performed. The value of the heat storage level thus obtained is added to and stored in the heat storage memory 9 described later. Here, for example, when the heat storage memory 9 stores the added value of the heat storage levels corresponding to the past four recordings for each heating element, FIG.
As shown in the figure, the added value of the heat storage level is 1st to 5th.
In addition to the division, the second division of 6 to 10 and the third division of 11 to 15, the number of pulse reductions is 1 for the first division, the number of pulse reductions is 3 for the second division, 3
A pulse reduction number of 5 is set for each section. More specifically, after recording the past four dot patterns through a certain heating element and then recording the current dot pattern, the dot pattern is added to the heat storage memory 9 by the past four recordings. When the added value of the stored heat level is present in the first section (1 to 5), the number of drive pulses applied to the heating element in this recording is reduced by one pulse and applied. The heat storage memory 9
In the case where the added value of the heat storage level stored in the second section (6 to 10) is present, the number of drive pulses applied to the heating element at the time of the current recording is reduced by 3 and applied. Further, when the added value of the heat storage level stored in the heat storage memory 9 exists in the third section (11 to 15), the number of drive pulses applied to the heating element in the current recording is reduced by 5 pulses. Will be applied.

Further, the RAM 6 has a text memory 7,
A print buffer 8, a heat storage memory 9, a heat storage counter 10 and the like are provided.
2 is stored. The print buffer 8 stores dot patterns for printing a plurality of characters and symbols as dot pattern data, and the thermal head 17 performs dot printing according to the dot pattern data stored in the print buffer 8. As described above, the added value of the heat storage level is stored in the heat storage memory 9, and the thermal head 17 is stored in the heat storage counter 10.
For each heating element, the heat storage state generated in each heating element based on the past heating history is stored. The operation of the heat storage counter 10 will be described later.

The input / output interface 10 has a keyboard 12, a disconnect switch 13, and a display controller (hereinafter referred to as LCDC) 15 having a video RAM 16 for outputting display data to the LCD 14.
And a driving circuit 18 for driving the thermal head 17
And a drive circuit 2 for driving the tape feed motor 19
0 are connected to each other.

Therefore, when a character or the like is input through the character keys of the keyboard 12, the text (document data) is sequentially stored in the text memory 7, and is transmitted to the dot pattern generation control program and the display drive control program. A dot pattern corresponding to a character or the like input via the keyboard 12 is displayed on the LCD 14 based on the information. The thermal head 17 is provided with a driving circuit 18.
, And prints the dot pattern data stored in the print buffer 8. In synchronization with this, the tape feed motor 19 controls the tape feed through the drive circuit 20. Here, the thermal head 17
A plurality of heating elements are provided, and characters and the like are printed on a tape by selectively driving each heating element via a drive circuit 18. Since the configuration of the tape printer is known, detailed description thereof is omitted here.

Next, a description will be given of a method of controlling the heat generation of each heating element of the thermal head 17 according to the first embodiment, which is performed in the tape printing apparatus configured as described above, with reference to FIG. FIG. 3 is an explanatory diagram schematically showing a method of controlling heat generation drive of the heat generation element. Note that 224 heating elements are formed in the thermal head 17, and accordingly, there are also 224 dot patterns recorded by each heating element, but FIG. 3 is simplified for convenience of explanation.

In FIG. 3, a first row L1, a second row L2,
Four rows of dot patterns of the third row L3 and the fourth row L4 have already been recorded, and the dot pattern of the fifth row L5 is to be recorded this time via the first to fifth heating elements. Here, in the first row L1, the dot pattern recorded by the first heating element has an energy level of 6
(20 drive pulses are applied to the heating element), and the dot pattern recorded by the second heating element has an energy level of 4 (8 driving pulses are applied to the heating element). The dot pattern recorded by the third heating element was recorded by the fourth and fifth heating elements with an energy level of 8 (63 driving pulses were applied to the heating element). The dot pattern is recorded at energy level 6. The dot patterns in the second to fourth rows L2 to L4 are also recorded in the same state as in the case of the first row L1. The numbers inside the circles indicating the dot patterns indicate the energy levels, respectively. In the fifth row L5 recorded this time, the dot pattern corresponding to the first of the third and the third heating elements has the energy level 6
And the dot pattern corresponding to the fourth heating element is recorded at energy level 4, and the dot pattern corresponding to the fifth heating element is stored at energy level 8
Recorded in.

After the dot patterns of the first to fourth rows L1 to L4 are recorded as described above, the heat storage memory 9 for storing the heat generation history of the first heating element stores the added value 8 of the heat storage level. It is remembered. Referring to the table 21 shown in FIG. 2, when a dot pattern is recorded by the first heating element in the first to fourth rows L1 to L4, the driving applied to the heating element at the energy level 6 is performed. Since the number of pulses is 20, and the heat storage level of each dot pattern is 2, the sum of the heat storage levels is 8.

Similarly, an additional value 4 of the heat storage level is stored in the heat storage memory 9 for storing the heat generation history of the second heat generating element. Referring to the table 21 shown in FIG. 2, this is because the second to fourth columns L1 to L4
When a dot pattern is recorded by the second heating element, the number of drive pulses applied to the heating element at energy level 4 is 8, and therefore, the heat storage level of each dot pattern is 1, so that the heat storage level is 1. This is based on the fact that the added value of the level is 4.

Further, an additional value 12 of the heat storage level is stored in the heat storage memory 9 for storing the heat generation history of the third heating element. Referring to the table 21 shown in FIG. 2, when a dot pattern is recorded by the third heating element in the first to fourth rows L1 to L4, the driving applied to the heating element at the energy level 8 is performed. Since the number of pulses is 63, and the heat storage level of each dot pattern is 3, the sum of the heat storage levels is 1
2

The heat storage memory 9 for storing the heating history of the fourth heating element and the heat storage memory 9 for storing the heating history of the fifth heating element have the same structure as that of the first heating element. Since they are the same, the added value 8 of the heat storage level is stored.

The case where the dot pattern of the fifth row L5 is recorded under the above conditions will be described. First, first
Immediately before the dot pattern is recorded by the second heating element, the added value of the heat storage level stored in the heat storage memory 9 is 8, which corresponds to the second division in the table 21,
The pulse reduction number at this time is 3 pulses. On the basis of this, when recording a dot pattern by the first heating element, a driving pulse of 17 pulses obtained by subtracting the aforementioned three pulses from 20 pulses corresponding to the energy level 6 is applied to the heating element. Recorded.

Immediately before the dot pattern is recorded by the second heating element, the added value of the heat storage level stored in the heat storage memory 9 is 4, and the table 21
Corresponds to the first section, and the pulse reduction number at this time is one pulse. Based on this, when recording the dot pattern by the second heating element, a driving pulse of 19 pulses obtained by subtracting the decreasing number of 1 pulse from 20 pulses corresponding to the energy level 6 is applied to the heating element. Recorded.

Further, immediately before the dot pattern is recorded by the third heating element, the added value of the heat storage level stored in the heat storage memory 9 is 12, and Table 2
1 corresponds to the third section, and the pulse reduction number at this time is 5 pulses. Based on this, when recording a dot pattern with the third heating element, the energy level 6
The 15 drive pulses obtained by subtracting the decreasing number of 5 pulses from the 20 pulses corresponding to are applied to the heating element and recorded.

Immediately before the dot pattern is recorded by the fourth heating element, the added value of the heat storage level stored in the heat storage memory 9 is 8, and
Corresponds to the second section, and the pulse reduction number at this time is 3 pulses. Based on this, when a dot pattern is recorded by the fourth heating element, a driving pulse of 5 pulses obtained by subtracting the above-mentioned 3 pulses from 8 pulses corresponding to the energy level 4 is applied to the heating element. Recorded.

Further, immediately before the dot pattern is recorded by the fifth heating element, the added value of the heat storage level stored in the heat storage memory 9 is 8, and
Corresponds to the second section, and the pulse reduction number at this time is 3 pulses. On the basis of this, when a dot pattern is recorded by the fourth heating element, a driving pulse of 60 pulses obtained by subtracting the decreasing number of 3 pulses from 63 pulses corresponding to the energy level 8 is applied to the heating element. Recorded.

As described above in detail, in the method of driving the heating element according to the first embodiment, the table 2 of the ROM 5
When energy is applied to each heating element in accordance with the energy level stored in a multi-valued manner in step 1, the heat storage level generated in each heating element is added over a plurality of recordings and stored in the heat storage memory 9. Then, the number of drive pulses corresponding to the energy level to be applied to each heating element is reduced based on the sum of the heat storage levels of each heating element stored in the heat storage memory 9 and applied to each heating element. With this configuration, it is possible to accurately grasp the heat storage state of each heating element and apply appropriate energy to each heating element. Thus, the size and density of the dot pattern recorded by each heating element can be made uniform.

In the table 21 of the ROM 5, the level of each energy is stored as the number of driving pulses applied to the heating element, and the number of driving pulses is reduced according to the heat storage state. Can be corrected based on the number of driving pulses, and the correction process can be simplified and performed easily.

Further, the heat storage state of each heating element stored in the table 21 is divided into a plurality of heat storage levels represented by the sum of the heat storage levels, and the correction amount (decrease number) of the drive pulse corresponding to each heat storage level ) Can be changed, so that the process of changing the correction amount of the drive pulse can be simplified and quickly and easily performed.

In the first embodiment, the accumulated value of the heat storage level over the past four recordings is stored in the heat storage memory 9 for each heating element. It can be arbitrarily changed according to the capacity of the memory 9.

Next, a method of controlling the heat generation of the respective heating elements of the thermal head 17 according to the second embodiment performed in the tape printing apparatus will be described with reference to FIGS. FIG. 4 shows a PD (Point Difference).
FIG. 5 is an explanatory diagram schematically showing the contents of a table storing the relationship between the size and the input level of energy applied to the heating element, FIG. 5 is a flowchart of a heat storage control program for the heating element, and FIG. 6 is a graph showing a relationship between a counter value and a decrease number of drive pulses.

In order to carry out the method of controlling the drive of the heating elements according to the second embodiment, a ROM corresponding to the size of the dot pattern recorded by each heating element is stored in the ROM 5.
A table 22 is stored in which the relationship between the D size and the input level of energy (expressed by the number of drive pulses) applied to the heating element is set and stored. In FIG. 4, the number of drive pulses 0 to 63 corresponds to each of the PD sizes 0 to 7. Further, the flowchart of the heat storage control program shown in FIG. Such a heat storage control program controls the number of drive pulses to be applied to each heating element to an appropriate number of pulses in consideration of the heat generation history counted by the heat storage counter 10 provided for each heating element. Program.

Here, a method of controlling the heat generation drive of the heat generation element will be described with reference to the flowchart shown in FIG. First, in step (hereinafter, abbreviated as S) 1, the heat storage counter 10 is set to 0, and initialization is performed. In S2, the PD size (0 to 7) is set for the dot pattern data for one row of each heating element of the thermal head 17.
). Here, 224 heating elements are formed in one row in the thermal head 17, and in S2, the PD size is obtained for 224 dot pattern data corresponding to one row.

In S3, the heat storage element 10 is calculated by calculating the amount of heat storage based on the previous heating operation of the heating element driven to generate heat this time. Specifically, the value of the PD size of the dot pattern at the time of the previous heat generation drive is added to the counter value (Nn-1) counted by the heat storage counter 10 based on the heat generation drive up to the previous time (two times before). The added value is set in the heat storage counter 10.

In the next step S4, a counter value (Nn) required for the current heating drive is calculated. Specifically, the counter value of the heat storage counter 10 (N
n-1) is multiplied by a predetermined heat storage contribution ratio α (a numerical value of 1.0 or less, which is experimentally obtained) (Nn = Nn-1 * α), and the counter value (N
n) is set in the heat storage counter 10. Here, the heat storage contribution rate α is integrated with the counter value (Nn−1) up to the previous recording based on the following reason. In other words, the state of heat storage in the heating element due to recording near the dot pattern to be recorded this time has a great effect on the current recording, while the heating element due to recording far from the dot pattern to be recorded this time. The state of heat storage does not have much effect on the current recording. In consideration of such a situation, in the process of S4, the heat storage contribution rate α is integrated with the counter value (Nn) calculated each time when the heating element is sequentially driven for heating next time, one after another. Things. As a result, in the heat storage counter value (Nn) calculated based on the heat storage in the heating element due to the recording near the dot pattern to be recorded this time, the integration number of the heat storage contribution rate α is small, in other words, the heat storage counter value (Nn) increases and the effect of heat storage is greatly evaluated. In addition, the heat storage counter value (Nn) calculated based on the heat storage in the heating element due to the fact that the dot pattern recorded this time was recorded far away contributes to the heat storage. The integration number of the rate α is large, in other words, the heat storage counter value (Nn) becomes small, and the influence of the heat storage is evaluated to be small. Based on this, it is possible to appropriately reflect the influence of heat storage accumulated in the heating element due to the past heat generation drive in the current heat generation drive, and as a result, to achieve uniform density in each dot pattern. Can be done.

In the subsequent S5, the energy level input to the heating element at the time of heating driving is determined. Specifically, a heat storage counter value (Nn) passing through the origin is used as a variable, and an equation of a straight line whose slope is a predetermined coefficient K (a numerical value of 1.0 or less) is assumed, and the heat storage counter value (N
n), the number of reduced drive pulses (P1 =
Nn * K)).

Here, the reduced number of the driving pulses (P1)
The method of calculating the following will be described with reference to FIG. In FIG. 6, the horizontal axis indicates the heat storage counter value (Nn), the vertical axis indicates the number of reductions in the drive pulse (P1), and a plurality of straight lines specified by different slopes K for each PD size are shown. . Line A corresponds to PD size 7 and its slope K
Is the largest. Line B corresponds to PD size 6,
The slope K is smaller than the straight line A. The straight line C is PD
It corresponds to size 1 and its slope K is even smaller than the straight line B. Although FIG. 6 shows only three straight lines A to C, straight lines are set for each PD size. Specifically, for example, if the PD size of the dot pattern of the heating element of interest at step S2 is PD7, the straight line A is selected, and the heat storage counter value (N
When n) is N, it can be seen that the decreasing number (P1) of the drive pulse is a P pulse as shown.

At S6, the average value P2 is obtained by averaging the reduction numbers P1 for each PD size in the dot pattern of one row. This is because if the reduction number P1 varies for dot patterns having the same PD size, there is a possibility that density unevenness may occur. Therefore, for a dot pattern having the same PD size, the reduction number (P
This is because the density is made uniform by averaging 1) and using the average value P2.

In S7, based on the PD size of the dot pattern obtained in S2 and the table 22 in FIG. 4, the reference input level (P
0: the number of drive pulses). In S8, S
The correction value (Pn = P0-P2) of the number of drive pulses is obtained by subtracting the average value (P2) of the decrease number from the number of drive pulses of the reference input level (P0) obtained in step 7. Then, in S9, the obtained correction value (Pn) is stored (stored) for the next processing.

At S10, it is determined whether or not the processing at S3 to S9 has been completed for all dot pattern data for one row. If not completed (S10:
(NO), the processes of S3 to S9 are performed again,
When the process is completed (S10: YES), the correction value (Pn) of the drive pulse obtained as described above in S11 is applied to each heating element to perform heating driving. Then, in S12,
It is determined whether the recording for one line by the thermal head 17 is completed. If the recording for one line has not been completed (S12: NO), the process returns to S1 to perform the processing for the dot pattern data in the next row, and the same processing as described above is performed for the dot pattern in the next row. . When recording for one line is completed (S12: YE
In S), the heat storage control process ends.

As described above, in the heating drive control method for the heating element according to the second embodiment, the counter value of the heat storage counter 10 is made to correspond in advance to the reduced number of drive pulses.
The number of drive pulse reductions is calculated based on the correspondence, and the number of drive pulses is reduced according to the number of reductions to drive the heating elements, so that the counter does not require a large-capacity memory. The heat storage control of the heating element can be easily performed by acquiring the number of reductions of the drive pulse corresponding to the value.

When calculating the counter value (Nn) required for the current heat generation driving, the counter value (Nn) is calculated.
n-1) is calculated by integrating a predetermined heat storage contribution rate α, so that the heat storage counter value calculated based on the heat storage in the heating element due to the recording near the dot pattern to be recorded this time (Nn) is the heat storage contribution rate α
Is small, in other words, the heat storage counter value (N
n) increases and the effect of heat storage is greatly evaluated. In addition, the heat storage counter value (Nn) calculated based on the heat storage in the heating element due to the fact that the dot pattern recorded this time is recorded far away, contributes to the heat storage. The number of integrations of α is large,
In other words, the heat storage counter value (Nn) becomes small, and the effect of heat storage is evaluated to be small. Based on this, it is possible to appropriately reflect the effect of heat storage accumulated in the heating element due to the past heat generation drive in the current heat generation drive, and as a result, to achieve uniform density in each dot pattern. Can be done.

[0052]

As described above, in the thermal recording apparatus according to the first aspect, when energy is applied to each heating element in accordance with the level stored in a multi-valued manner in the first storage means,
The heat storage state generated in each heating element is added over a plurality of recordings and stored in the second storage means, and based on the heat storage state of each heating element stored in the second storage means in this way, via the correction means. In addition to correcting the energy to be applied to each heating element and applying the corrected energy to each heating element via the energy applying means, the state of heat storage in each heating element is accurately grasped and Appropriate energy can be applied to the heating element. As a result, the size and density of the dot pattern recorded by each heating element can be made uniform.

In the thermal recording apparatus according to the second aspect, since the level of energy applied to each heating element can be corrected by the number of drive pulses, the correction process is simplified and facilitated. It is possible to do.

Furthermore, in the thermal recording apparatus according to the third aspect, the heat storage state of each heating element may be divided into a plurality of heat storage levels, and the correction amount of the drive pulse may be changed according to each heat storage level. In addition, the processing for changing the correction amount of the drive pulse can be simplified and performed quickly and easily.

In the thermal recording apparatus according to the fourth aspect, the counter value of the heat storage counter is made to correspond in advance to the number of drive pulse reductions, and the number of drive pulse reductions is calculated based on the correspondence. Since the number of driving pulses is reduced in accordance with the number of the driving pulses to drive the heating element, the number of the driving pulses corresponding to the counter value is obtained without requiring a large-capacity memory to obtain the heating element. Heat storage control can be easily performed.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a control configuration of a tape printer.

FIG. 2 is an explanatory diagram showing a table in which an energy level, the number of pulses, a heat storage level, a heat storage level addition value, and a pulse reduction number are stored in correspondence with each other.

FIG. 3 is an explanatory diagram schematically showing a method of controlling heat generation drive of the heat generation element according to the first embodiment.

FIG. 4 is an explanatory diagram schematically showing the contents of a table storing a relationship between a PD size and an input level of energy applied to a heating element.

FIG. 5 is a flowchart of a heat storage control program for a heating element according to the second embodiment.

FIG. 6 is a graph showing a relationship between a counter value counted by a heat storage counter and a decrease number of drive pulses.

[Explanation of symbols]

 Reference Signs List 1 control device 2 CPU 5 ROM 6 RAM 9 heat storage memory 10 heat storage counter 17 thermal head 21 table 22 table

Claims (4)

[Claims] 1. A thermal head in which a plurality of heating elements are formed; a first storage means for storing a level of energy applied to each of the heating elements in a multi-valued manner; and a storage in the first storage means. A second storage unit for adding and storing the heat storage state generated in each heating element over a plurality of recordings when energy is applied to each heating element according to the set level; and Energy correction means for correcting energy to be applied to each heating element based on the stored heat storage state of each heating element; and energy application for applying the energy corrected via the energy correction means to each heating element. And a thermal recording device. 2. The apparatus according to claim 1, wherein the first storage unit stores the level of each energy as the number of drive pulses applied to the heating element, and the energy correction unit corrects the number of drive pulses. 2. The thermal recording apparatus according to 1. 3. A heat storage state of each heating element stored in the second storage means is divided into a plurality of heat storage levels, and the energy correction means changes a correction amount of a drive pulse corresponding to each of the heat storage levels. 3. The thermal recording apparatus according to claim 2, wherein the recording is performed. 4. The second storage means includes a heat storage counter, and a drive pulse corresponding to the counter value of the heat storage counter based on a predetermined relationship in which a counter value of the heat storage counter is associated with a decrease number of the drive pulse. 4. An operation means for calculating the number of reductions in the drive signal, wherein the energy correction means reduces the number of driving pulses in accordance with the number of reductions calculated by the operation means. Thermal recording device.