JPH089238B2 - Thermal recording device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermal recording apparatus, and more particularly, to improvement of recording quality when performing waveform recording.

<Prior Art> As a recorder, a plurality of heating elements arranged at regular intervals so as to form a line thermal head are selectively driven to generate heat, and the heat-sensitive recording paper is colored or recorded based on the generated heat. 2. Description of the Related Art A thermal recording device is used in which recording is performed by transferring ink of an ink ribbon onto paper.

FIG. 12 is a block diagram showing an example of such a conventional device, and FIG. 13 is a timing chart showing an example of the operation of the circuit of FIG. Data of m dots for one line shown in (a) are sequentially stored in the shift register 1 in accordance with m clocks CLK shown in (b). Shift register 1
When the data for one line is stored in, the data is latched in the latch 2 by the latch pulse LAT shown in (c). The output data of these latches 2 is applied to one input terminal of each NAND gate 3. An enable signal EN 'shown in (d) is commonly applied to the other input terminals of these NAND gates 3 via an inverter 4. The dash “′” indicates that the operation is negative logic. The output terminal of the NAND gate 3 is connected to one end of a heating element 5 that constitutes a thermal head, and the other end of the heating element 5 is commonly connected to the positive terminal of a DC power supply 6.

In such a configuration, as the recording data of each line, for example, the heating element corresponding to the maximum value to the heating element corresponding to the minimum value is recorded so that the maximum value and the minimum value of the measurement value in each measurement cycle are recorded in a line shape. The interpolated data is added so as to simultaneously drive a plurality of heating elements continuous in the array direction up to.

As a result, during t ₀ when the enable signal EN ′ is at the L level, a drive current flows from the DC power source 6 to the heating element 5 and recording is performed based on the recording data of one line. Then, the recording paper (not shown) is fed line by line every time the recording operation for one line is completed.

<Problems to be Solved by the Invention> However, according to such a conventional configuration, the recording paper is moved by one line each time one line is recorded, and therefore the recording result is shown in FIG. Such a large stepped portion appears due to the feeding pitch P of the recording paper. This stepped portion becomes larger as the recording paper feeding speed becomes faster, which is not preferable.

The present invention focuses on such a point, and an object thereof is to provide a thermal recording apparatus which can obtain a recording result with a small stepped portion due to the feeding pitch of the recording paper.

<Means for Solving the Problems> A thermal recording apparatus of the present invention is configured to selectively drive a plurality of heating elements arranged at regular intervals so as to form a line thermal head based on recording data to generate heat. In a thermal recording device for recording on recording paper based on the heat generation, recording paper feeding means for feeding the recording paper to the printing dots of the heating element by dividing the feeding into a plurality of times, and feeding the recording paper. A heat generation number setting means for a heat generating element in which a plurality of heat generation times based on the synchronized recording data are set, and a heat storage temperature storage means for storing heat storage temperature data related to the recording operation of the heat generating element,
A comparison means for comparing the heat storage temperature data of the heat storage temperature storage means with a preset temperature to determine the size and outputting comparison data, and an output from the comparison means and the heat generation number setting means It is provided with a calculation means for outputting a drive signal of the heating element from an output signal, and a heat storage temperature data update means for updating the heat storage temperature data of the heat storage temperature storage means based on the output signal from the calculation means. And

<Operation> The recording paper feeding means divides the feeding of the recording paper into a plurality of times with respect to the print dots of the heating elements and sends the divided recording paper. The heat generation number setting means outputs a heat generation signal to the heat generating element a plurality of times in synchronization with the paper feed pitch. The heat storage temperature storage means stores heat storage temperature data related to the recording operation of the heat generating element, and this temperature data is updated according to the heat generation state of the heat generating element. The comparison means compares the current temperature data stored in the heat storage temperature storage means with a preset temperature and determines the magnitude thereof, and outputs a heat generation signal to be applied to the heat generating element according to the determination result.

As a result, the resolution of the feed pitch of one line of the recording paper becomes finer, the step due to the feed pitch of the recording paper becomes smaller, and the heating element of the thermal head is damaged due to overheating, and the print quality can be improved. .

<Example> Hereinafter, an example of the present invention is described in detail using a drawing.

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, A is a digital one-shot section that generates recording data for driving the heating element, and B is a heat history control section that controls the heating temperature of the heating element.

In the digital one-shot section A, the input data D _i to be recorded is added to the data selector 7 as a selection signal. This data selector 7 uses the input data D _i “1”,
The predetermined data P _i−1 selected according to “0” is output to the data conversion unit 8 and the subtractor 9. When the data P _i-1 added from the data selector 7 is other than “0”, the data conversion unit 8 outputs the data d _i ′ of “1” to one input terminal of the AND gate 18 constituting the thermal history control unit B. For example, an OR gate is used. The subtractor 9 subtracts P _i = P _i-1 -1 from the input data P _i-1 . However,
The subtractor 9 subtracts only natural numbers, for example, P _i-1
When is 0, 0 is output as it is as P _i . The praise result P _i is temporarily stored in the dual port memory 11 via the latch 10. Output data of dual port memory 11
P _i-1 is applied to the data selector 7 via the latch 12.

In the thermal history control section B, the memory 13 stores in advance the heat storage temperature data related to the recording operation of the plurality of heating elements forming the thermal head 19. The heat storage temperature data stored in this memory 13 is stored in the temperature sensor such as the thermistor.
According to the ambient temperature of the thermal head 19 measured at 20, the predetermined current heat storage temperature data R _i-1 and the output data of the AND gate 18 related to the presence or absence of recording are used as addresses, and the next heat storage temperature data _Read as R _i . The heat storage temperature data R _i read from the memory 13 is stored in the latch 14
Is temporarily stored in the dual port memory 15 via the. Then, the heat storage temperature data R _i temporarily stored in the memory 15
Is read as the above-mentioned current heat storage temperature data R _i−1 , is added as an address to the memory 13 via the latch 16, and is also added to one input terminal of the comparator 17.
A preset temperature data SD is added to the other input terminal of the comparator 17. The output signal of the comparator 17 is applied to the other input terminal of the AND gate 18. The output data O _i of the AND gate 18 is applied to the memory 13 as an address as described above, and is also applied to the heating element of the thermal head 19 as a drive signal. Reference numeral 21 is a thermosensitive recording paper on which color recording is performed by the heat generated by a plurality of heating elements constituting the thermal head 19, and is sent by a motor 22 at a predetermined speed. A timing control circuit 23 outputs a control signal for controlling the operation of each unit. As the thermal head 19 portion, one having the same structure as that shown in FIG. 12 can be used.

The operation of the apparatus thus configured will be described with reference to the timing chart of FIG.

In FIG. 2, m-dot data DATA is transferred to the thermal head 20 four times, and an enable signal EN ′ is applied four times to record one line. Here, the pulse width t ₀ ′ of the enable signal EN ′ is 1/4 of the pulse width t ₀ in FIG. That is, the energy applied to the heating element 5 by one driving is 1/4 of that in the case of FIG.
One line is recorded by sending A and the enable signal EN '. The recording paper 21 is also fed stepwise in synchronization with this sequence by dividing it into 1/4 steps in FIG.

In such a driving method, since the pulse width t ₀ ′ of the enable signal EN ′ is constant, for example, the recording condition of the recording sequence of the line starting from the data D ₁ up to the data D ₄ and the data D ₂ at the head. The recording conditions of the recording sequence of the lines up to the data D ₅ are equal. Therefore, the feeding speed of the recording paper 21 is equal, that is, the data transfer period D _{n in} FIG.
Is 1/4 of the data transfer cycle of FIG. 13, the resolution along the time axis direction is four times that of the drive method of FIG. 12 according to the drive method of FIG.

FIG. 3 is an example of recording by such a recording method. The recording paper is fed in the direction of arrow Y by 1/4 of the pitch P shown in FIG. The heating element 5 is driven in four times in synchronization with the paper feed pitch as shown in ac. “A” shows the driving state of the heating element 5 ₄ , “b” shows the driving state of the heating element 5 ₅ , and “c” shows the driving state of the heating element 5 ₆ . Heating element
The recording pattern PTa by 5 ₄ is data selector 7 at time t _1.
Input data D _i “1” is added to
Recorded by rotating the drive, the input data D _i to the data selector 7 in the recording pattern PTb the time t ₂ due to heat generation elements 5 ₅ "1"
Recorded by four driving continuous due to is applied, the recording pattern PTc the consecutive four driving due to the input data D _i "1" is added to the data selector 7 at time t ₃ by heating element 5 ₆ Recorded by. Similarly, each recording pattern is recorded by continuously driving the corresponding heating element in four times in synchronization with the paper feed pitch. When the input data D _i “1” is added again to the data selector 7 of the heating element that is being driven, the driving is executed four more times from that point, and the recording pattern becomes longer.

As is clear from the recording result of FIG. 3, the resolution of the paper feed pitch is higher than that of the conventional recording result, and therefore the maximum of the stepped portion due to the paper feed pitch when the paper is fed at the same speed. The height is smaller than before, and the waveform curve recording results are smooth. Since the input data is fetched in synchronization with the paper feed timing, it is possible to faithfully record a signal waveform having a higher frequency than in the conventional case.

FIG. 4 is a timing chart for explaining the operation of the digital one-shot section A. The memory 11 stores the trigger data corresponding to each dot.
A _l is the trigger data P corresponding to the m-1st dot.
_{i−1, l} is stored. By adding an address A _l in the l-th clock of the internal clock CLK as shown from the timing control circuit 23 (a), the trigger data corresponding to m-l-th dot as shown from the memory 11 in (b) P _{i−1, l} is read. The trigger data read from the memory 11 is latched in the latch 12 as shown in (c) at the rising edge of the (l + 1) th clock,
It is added to the data selector 7. The data selector 7 is
When the input data d _{i, l} is “0”, the input data P _{i−1, l}
Is output as it is, and when the input data d _{i, l} is “1”, the data selector 7 is previously used instead of the input data P _{i−1, l.}
The data CD set in is output. In the case of this embodiment, "4" is output because one line's worth of data is recorded in four times. The output data of the data selector 7 is added to the data converter 8 and the subtractor 9. The data converter 8 receives the data P added from the data selector 7.
_{When i−1, l} is other than “0”, the data d _i ′ is set to “1” and added to the AND gate 18 of the thermal history control unit B. The subtractor 9 is
The calculation of P _{i−1, l} −1 is performed, and the calculation result P _{i, l} is output to the latch 10 as shown in (d). Latch 10 is l
At the rising edge of the + 2nd clock, the calculation result P _{i, l} of the subtractor 9 is latched as shown in (e), and the data P _{i, l} is output to the memory 11 as the address A _l during the clock cycle.

Such a series of operations is performed by each data D _1-
Repeated m times for D ₅ interval.

Next, how the data of the address _{Al in} the memory 11 changes according to the repetition of the interval period will be described.

FIG. 5 shows a data change of each part when a certain address _Al of the memory 11 is fixed.

The data D _{i, l} input to the data selector 7 at the interval k shown in (a) is “1” as shown in (c).
Let's say. At this time, "4" is set as the output data of the data selector 7 as shown in (d).
On the other hand, the output data of the data converter 8 is the data selector 7
Since the output data of is not "0", it becomes "1" as shown in (e), and the recording data is given to the heat history control section B. In the following intervals k + 1, k + 2, k + 3, the data is subtracted by "1" by the subtractor 9 as shown in (f).

Through this process, the data D at the interval k
Interval k to k is triggered by the input of "1" of _{i, l}
The recording data is added from the data conversion unit 8 to the heat history control unit B four times up to +3.

Such a series of operations includes intervals k + 5 and k +
The same is true when "1" is input as the data D _{i, l} in 8, and the digital one-shot section A operates as if it were a retriggerable monostable multivibrator, and the data conversion section 8 uses the data D _{i. Thus, the} record data is output to the history control unit B at four intervals starting from the interval in which "1" is input as _l .

That is, the digital one-shot section A operates by using the input data D _{i, l} as a trigger to extend the input data a predetermined number of intervals set by the data selector 7.

 Next, the operation of the heat history control unit B will be described.

For example, in the period of intervals k + 5 to k + 10 in FIG. 5, the recording data d _i ′ output from the data converting unit 8 is continuously “1”, and such recording data d _i ′ is kept as it is. When transferred to, the drive current continuously flows through the corresponding heating element. As a result,
Not only does the temperature of the heating element rise significantly and uniform recording quality cannot be maintained, but in the worst case, the heating element may burn out.

Therefore, the heat history control unit B determines the recording data based on the heat storage temperature data stored in the memory 13 in advance as described above.
After performing data processing such as thinning out d _i ′, the recording data O _i is transferred to the thermal head 19.

By performing one line recording at four times the data transfer as in the present embodiment, the pattern of drive pulses applied to the heat generating element 5 by way of taking each time the data D ₁ to D _4, as shown in FIG. 6 It will be one of 15 ways (2 ⁴ -1 = 15). That is, the heating element 5 is driven and controlled according to the heat storage temperature, and as a result, driven according to any one of these 15 patterns.

In FIG. 2, one line is recorded by sending the data DATA and the enable signal EN ′ four times, but the number of times is not limited to four, and n times (n is an integer of 2 or more). ). The driving pattern for n times
There are 2 ⁿ -1 ways.

 Details of such heat storage control will be described.

At the address A _{x of the} memory 15, heat storage temperature data corresponding to the mxth heating element in the main scanning direction to be recorded is stored as shown in FIG. Timing control circuit
23 sends the address A _l in a memory 15 that temporarily stores the heat storage temperature data in l-th clock of the internal clock CLK shown in (a) of the timing chart of Figure 8. As a result, the memory 15 outputs the heat storage temperature data R _{i−1, l} corresponding to the m−1 th heating element, as shown in FIG.

In the 1 + 1 cycle of the internal clock CLK, the latch 16 is set at (c) in FIG. 8 due to the rise of the clock CLK.
As shown in, the heat storage temperature data R _{i−1, l} is latched.
The heat storage temperature data R _{i−1, l} latched by the latch 16 is applied to the comparator 17 and compared with the initially set temperature data SD. The heat storage temperature data R _{i−1, l} and the temperature data SD are quantized into a plurality of s bits. For example, if the temperature data SD is set to 200 ° C. and the heat storage temperature data R _{i−1, l} is 100 ° C., the comparator 17 outputs “1” to the AND gate 18, and the temperature data SD is 20.
Heat storage temperature data R _{i−1, l} is set to 0 ° C and 250 ° C
Then, "0" is output to the AND gate 18. In this l + 1 clock cycle, the recording data d ′ _{i, l} is read from the data conversion unit 8 to the AND gate 18,
The logical product of the output data of the comparator 17 as shown in (f) is obtained. The output data O _i of the AND gate 18 is used as data to be actually recorded, and the heating element 5 of the thermal head 19 is used.
Is added to That is, the heating element 5 of the thermal head 19 is in the recording state only when the recording data d ′ _{i, l} is “1” and the heat storage temperature data R _{i−1, l} is lower than the temperature data SD.

In the cycle of l + 1, the following control is performed simultaneously with the above process. That is, the heat storage temperature data R _{i−1, l} and the output data O _i of the AND gate 18 are input to the memory 13 as addresses. Here, since the comparator 17 and the AND gate 18 can be configured by a high speed gate element, the AND gate
The settling of the output data O _i of 18 is about several tens of ns, and if the clock cycle is several 100 ns, the data read from the memory 13 can be completed within one clock.

The memory 13 outputs the following heat storage temperature data R _{i, l} as shown in (d) according to the addresses R _{i−1, l} and O _i . For example, when the heat storage temperature data R _{i−1, l} is 100 ° C.,
If O _i is 1, the 180 ° C bit data is output as the heat storage temperature data R _{i, l} , and if O _i is 0, the heat storage temperature data R
Outputs bit data at 50 ° C as _{i, l} .

In the l + 2 cycle, the latch 14 causes the memory 13 to rise at the rising edge of the clock CLK in the l + 2 cycle as shown in (e).
The heat storage temperature data R _{i, l} output from the device is latched. Moreover, the data latched in the latch 14 are written is applied to the other port of the memory 15 to the address A _l.

These series of operations are pipelined in parallel,
In the l + 1 clock cycle, the heat storage temperature data R _{i−1, l + 1} is read from the memory 15.

By performing such an operation m times, the thermal head 19 receives m recording data. The timing control circuit 23 activates the latch pulse LAT as shown in FIG.
As shown in FIG. 5, the enable signal EN 'is activated once for the time t', and the drive current is passed through the heating element 5. These m
The data transfer, the latch pulse LAT, and the enable signal EN 'are repeated a plurality of times. FIG. 2 shows an example of repeating four times.

Next, the heat storage temperature data setting of the memory 13 will be described.

The temperature change of the heating element 5 of the thermal head 19 can be simulated by the amplitude and pulse width of the drive pulse with the initial temperature T ₀ as a reference. That is, the thermal head
The structure of 19 is known, and the physical constants of each part are also known. From these, the thermal response of the thermal head 19 can be modeled and described using the heat conduction equation. By giving an initial temperature to this heat conduction equation as an initial condition and an amplitude and a pulse width of a driving pulse as input energy to the system, the thermal head 19 at each time is numerically calculated.
The temperature of the heating element 5 can be simulated. In addition,
Since the heat conduction equation is non-linear, a numerical calculation by a computer is performed using the one-dimensional finite element method, and the temperature state after data transfer is simulated and predicted.
The table is stored in the memory 13.

In the configuration of FIG. 1 described above, since the transfer cycle of m dot data to the thermal head 19 and the pulse width of the enable signal EN ′ are constant, the temperature after data transfer is predicted by simulation if the initial temperature T ₀ is known. it can. Ninth
The figure is an explanatory diagram of such a simulation state,
(A) shows the temperature change state when the drive pulse is added for the time t ', and (b) shows the temperature change state when the drive pulse is not added.

In the memory 13, the temperature T ′ after the transfer cycle when the drive pulse is applied and when the drive pulse is not applied is tabulated in advance as data using the initial temperature T ₀ as a parameter. That is, by setting the heat storage temperature data R _{i−1, l} as the initial temperature T ₀ and inputting the output signal O _i of the AND gate 18 to the address of the memory 13 as the ON / OFF signal of the driving pulse, the memory 13 transfers the cycle. The subsequent temperature _T'is output as bit data R _{i, l} .

By storing such data in the memory 13, the heat storage temperature is sequentially calculated. Then, the heat storage temperature data and the set temperature are compared one by one in the comparator 17, and as a result, the pulse train that matches the past heat storage temperature data is selected from the plurality of pulse trains in FIG. High thermal history control is performed.

In the above description, the temperature control is an open loop. Moreover, an error occurs in the simulation data depending on the ambient temperature. Therefore, the temperature sensor 20 measures the temperature of the heat dissipation plate of the thermal head 19, adds the measured data TD to the memory 13 as an address, and switches the data in the memory 13. Further, when the temperature of the heat dissipation plate of the thermal head 19 rises too much, the drive pulse is cut so as to prevent the temperature from further rising.

In addition, the pulse width of the drive pulse may be variable in order to improve the recording quality according to changes in the chart feed speed and the ambient temperature. In this case, change the address of memory 13 according to the chart feed speed and ambient temperature.
The data read from 13 should be changed.

With such a configuration, basically, the application pattern of the drive pulse of the thermal head can be finely set by a simple combination of one read-only memory and the comparator, and the recording quality can be improved.

FIG. 10 is a block diagram showing a modified example of the present invention,
It shows a case where there are two types of recording lines, and the portions common to FIG. 1 are given the same reference numerals with the suffixes of ₁ and ₂ corresponding to the types of recording lines.

That is, in FIG. 10, the digital one-shot section A has two systems of digital one consisting of a data selector 7 to which subscripts _{1 and 2} are added, a data conversion section 8, a subtractor 9, latches 10 and 12, and a memory 11. A shot loop is provided. on the other hand,
The thermal history control unit B has a comparator 17 for processing the data output from each digital one-shot loop system.
And AND gate 18 are provided in two systems, and the output data of these two systems of AND gates 18 ₁ and 18 ₂ are applied to the thermal head 19 via the OR gate 24.

In such a configuration, recording with different line types is performed as follows. It is assumed that one of the data selectors 7 ₁ is set to "4" as the set value CD ₁ , and the other data selector 7 ₂ is set to "6" as the set value CD ₂ .

FIG. 11 is a timing chart for explaining the operation, which corresponds to FIG. 5 described above, and shows a change in data corresponding to any one dot in the transfer interval. Is.

When the data D _1i input to the data selector 7 ₁ of _one system of the digital one-shot section A becomes "1" as shown in (c) at the interval k shown in (a), the output data of the data selector 7 ₁ CD as shown in (d)
The value "4" of ₁ is set. The output data d ′ _1i of the data conversion unit 8 ₁ becomes “1” as shown in (e) because the output data of the data selector 7 is “4”, and _one of the AND gates 18 ₁ of the history control unit B Apply recording data to the input terminal of. In a subsequent interval k + 1, k + 2, k + 3, as the data is indicated by the subtractor 9 ₁ (f) "1"
Are subtracted one by one. By this process, the data of "1" input to the data selector 7 ₁ at the interval k.
4 from interval k to k + 3 triggered by D _1i
So that recording data in the history control unit B is applied from the data conversion unit ₈₁ over time.

Such a series of operations is performed by the intervals k + 7 and k +
The same is true when “1” is input as the data D _{1i in} 9, and the digital one-shot unit A operates as if it were a retriggerable monostable multivibrator, and the data conversion unit 8 ₁ outputs the data D _1i as data D _1i. The recording data is output to the AND gate 18 ₁ of the history control unit B at four intervals starting from the interval at which "1" is input.

Such an operation is also executed in the other system with the subscript ₂ shown in (g) to (k). However, since "6" is set in the data selector 7 ₂ as the data CD ₂ , the interval k is triggered by the data D _2i of "1" input to the data selector 7 ₂ at the interval k.
The recording data is added to the AND gate 18 ₂ of the history control unit B from the data conversion unit 8 ₂ six times from (1) to k + 5.

A same when "1" as the data D _2i is input in the interval k + 7 and k + 8, the digital one-shot unit A is as if operates as Ritori Reconfigurable monostable multivibrator, the data conversion unit ₈₂ is data D _The recording data is output to the AND gate 18 ₂ of the history control unit B at six intervals starting from the interval at which "1" is input as _2i .

That is, the digital one-shot section A
D _1i, operates to stretch the predetermined interval times arguments set the input data by the data selector 7 _1, 7 ₂ of the set data CD _1, CD ₂ as a trigger D _2i, the set data CD _1, CD ₂ The recording line width will be changed accordingly.

Temperature data SD ₁ and SD ₂ of the comparators 17 ₁ and 17 ₂ of the heat history control unit B
Sets the recording density of the data d' _1i , d' _2i output from each system of the digital one-shot section A individually. For example, when the temperature data SD ₁ of the comparator 17 ₁ is set to 0.99 ° C., the comparator 17 ₁ only when the temperature data R _1-1 applied from the latch 16 is lower than 0.99 ° C. "1" Is output to the AND gate 18 ₁ . AND gate 18 ₁ is this comparator 17 ₁
Thus, the logical product of the output data of ₁ and the output data of the data converter 8 ₁ is output to the OR gate 24, and the heat storage temperature of the heating element is suppressed to a value near the temperature data SD ₁ . Here, the level of the heat storage temperature is related to the level of the recording temperature, and the recording density becomes darker as the heat storage temperature becomes higher. That is, the recording density can be individually set by the temperature data SD ₁ and SD ₂ of the comparators 17 ₁ and 17 ₂ .

Thus, according to the configuration of FIG. 10, the data selector
The recording line width can be set by the data CD ₁ and CD ₂ of 7 ₁ and 7 ₂ , and the recording density can be set by the data SD ₁ and SD ₂ of the comparators 17 ₁ and 17 ₂ . Therefore, for example, by setting CD ₁ = 4, CD ₂ = 6, SD ₁ = 200 ° C, SD ₂ = 150 ° C, the line of input data d _1i can be recorded finely and densely, and the line of input data d _2i Lines can be recorded with thick and thin lines. At the intersection of the two types of lines, the dark line is preferentially recorded due to the function of the OR gate 24.

Although an example of two types of recording lines has been described in FIG. 10, three or more types of recording lines can be simultaneously recorded by adding a system for the digital one-shot section and a system for the thermal history control section as needed.

Further, the memories 11 ₁ and 11 ₂ may be arranged such that the high-order plural bits and the low-order plural bits of one memory are respectively allocated.

In addition, continuous lines can be
The types of recording lines such as broken lines and chain lines can be further increased. In this case, on / off control of data input to the AND gate 18 system and data externally input to the data selector 7 system may be performed by the gate.

<Effects of the Invention> As described above, according to the present invention, recording paper feeding means for feeding the recording paper to the print dots of the heating element in a plurality of divided times and feeding the recording paper are synchronized. Heat generation number setting means of the heat generating element in which a plurality of heat generation times are set based on the recording data, heat storage temperature storing means storing heat storage temperature data related to the recording operation of the heat generating element, and heat storage of the heat storage temperature storing means Driving the heating element based on a comparison means for comparing the temperature data with a preset temperature and judging the magnitude of the temperature data and outputting the comparison data; and an output from the comparison means and an output signal from the heat generation number setting means. Since the calculation means for outputting a signal and the heat storage temperature data updating means for updating the heat storage temperature data of the heat storage temperature storage means on the basis of the output signal from this calculation means are provided, the recording paper feed pitch is set. Due to this, the step difference becomes small, and it is possible to realize a thermal recording device with good recording quality without complicated calculations.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a timing chart for explaining the operation of FIG. 1, FIG. 3 is a recording example diagram by the apparatus of FIG. 1, and FIG. 5 is a timing chart for explaining the operation of the digital one-shot section, FIG. 5 is an explanatory view of data changes in the digital one-shot section of FIG. 1, and FIG. 6 is an example of drive pulse patterns according to the timing chart of FIG. , FIG. 7 is a perspective view of the main part of FIG. 1, FIG. 8 is a timing chart explaining the operation of the heat history control unit of FIG. 1, and FIG. 9 is an explanatory view of simulation data used in the present invention. FIG. 10 is a block diagram showing an application example of the present invention, FIG. 11 is an explanatory diagram of data changes in the digital one-shot section of FIG. 10, and FIG. 12 is a block diagram showing an example of such a conventional device, Figure 13 shows the operation of the circuit in Figure 12. Timing chart showing,
FIG. 14 is a diagram showing a conventional recording example. 1 …… Shift register, 2,10,12,14,16 …… Latch, 3
...... NAND gate, 4 ... Inverter, 5 ... Heating element, 7 ... Data selector, 8 ... Data conversion unit, 9 ...
… Subtractor, 11, 15 …… Memory (dual port RAM), 13
…… Memory (ROM), 17 …… Comparator, 18 …… And gate, 19 …… Thermal head, 20 …… Temperature sensor, 21 ……
Chart paper, 22 …… Motor, 23 …… Timing control circuit, 24
…… Or gate.

Claims (2)

[Claims] 1. A heat-sensitive apparatus for selectively driving a plurality of heating elements arranged at regular intervals so as to form a line thermal head based on recording data to generate heat, and recording on a recording sheet based on the generated heat. In the recording apparatus, a recording paper feeding unit that divides the feeding of the recording paper with respect to the print dots of the heating element into a plurality of feedings, and a plurality of times of heat generation based on the recording data synchronized with the feeding of the recording paper is set. Heat generation frequency setting means for the heat generating element, heat storage temperature storing means for storing heat storage temperature data related to the recording operation of the heat generating element, heat storage temperature data of the heat storage temperature storing means and preset temperature. Of the driving signal of the heat generating element based on the output from the comparing means and the output signal from the heat generation number setting means. Calculating means for outputting a thermal recording apparatus comprising the heat storage temperature data updating means for updating the heat storage temperature data of the heat storage temperature storage means based on the output signal from the arithmetic means. 2. A thermal recording apparatus according to claim 1, wherein a plurality of heating frequency setting means of said heating element are provided in accordance with the measurement channels.