JP2001138561A - Driver and driving method for thermal head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To optimize the print quality of a thermal sheet or the erasure quality of rewrite media by controlling the applying pulse without requiring any addi tional resistor. SOLUTION: Heaters of a thermal head for heating a printing material being heated and a heating control means for heating the heaters at a plurality of different temperatures are provided. The heating control means applies a plurality of pulses for heating the heaters to a first temperature TE in one line period and applies a pulse for heating the heaters to a second temperature TP in one line period having a pulse width different from that of the pulse for heating the heaters to the first temperature TE.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer capable of outputting different heating temperatures during the same scanning, which is suitable for, for example, erasing and coloring of rewritable media (rewritable paper) and different coloring of thermosensitive paper. The present invention relates to a head driving method and apparatus.

[0002]

2. Description of the Related Art A driving method in which a pulse is applied several times during one line period has been used in a conventional one-input thermal head. In this driving method, it was possible to control subtle coloring and decoloring of the medium by controlling the maximum temperature of the heating element together with the application time. However, there is a disadvantage in that the finer the gradation, the longer the one-line cycle time.

FIG. 5 is an explanatory view of a conventional one-input thermal head driving method. 5, relative to rewrite the paper, T _P is defined which is higher temperatures for color development and decolorization temperature T _E which is at a low temperature of for decolorization.

[0004] and strobe (STR) signal for driving the heating elements of the thermal head for rewriting media, strobe (STR) signal, the erase pulse is heating-up period to decoloring temperature T _E for decoloring It turns on during τ _ES and the decolorizing temperature holding time τ _EK . Further, for printing, the printing pulse is set to the color application time τ _PI on following the erasing temperature holding time τ _EK of the erasing pulse. Therefore, if τ _PD is the color development and cooling time, the one line cycle is as follows at the minimum.

The minimum time of one line cycle = τ _ES + τ _EK + τ _PI + τ _{PD With a} conventional one-input thermal head, it cannot be made smaller than the minimum time. Note that τ _ED in FIG. 5 is the decolorizing temperature drop time.

It is disclosed in Japanese Patent Application No. Hei 10-1 to optimally control binary density data using a binary input thermal head.
No. 2320. This produces two types of energy, high and low, by optimizing the application time while keeping the applied power constant.

Further, in Japanese Patent Application No. 11-183042, by providing an additional resistor in addition to the heating element, a difference is generated in the power applied to the heating element, and the printing quality is optimized.

[0008]

SUMMARY OF THE INVENTION In the above prior art,
There were the following issues.

(1) In the method of driving a one-input thermal head, the time required for one line cycle is obtained by applying several pulses (print pulses for different numbers of colors) to the heating element in one line cycle. The media processing speed slowed down.

(2) Rewrite media and the like require high energy for a short time during printing, but have sufficient erasing characteristics at the time of erasing by holding at a lower temperature for a longer time than at the time of printing. Therefore, after a short pulse for erasing is applied several times in one line cycle, a long pulse for printing is applied for the remaining time to cool. For this reason, one line cycle requires a longer time than normal printing, and the degree of freedom in pulse setting is impaired.

(3): In the thermal head for binary input,
In order to secure a sufficient erasing time and the like, it is necessary to use a special thermal head provided with an additional resistor separately from the heating element.

Therefore, the present invention solves the above-mentioned conventional problems and optimizes the printing quality of thermal paper and the like and the erasing quality of rewritable media by controlling the applied pulse without providing the additional resistor. The purpose is to make.

[0013]

The above object of the present invention can be achieved by the following constitutions.

(1): A heating element of a thermal head for heating a printing object to be heated, and heating control means for heating the heating element at a plurality of different temperatures, wherein the heating control means a plurality of pulses for heating to a first temperature T _E is applied between the one-line period, the second temperature T said for heating the _P first temperature T _E of the heating element during one line period A pulse having a different width from the applied pulse is applied.

(2) In the thermal head driving method, when the heating element is heated by the heating control means,
The width of the applied pulse is controlled depending on whether the heating element has been heated before.

(3): A heating element of a thermal head for heating the printing object to be heated, and heating control means for heating the heating element at a plurality of different temperatures, wherein the heating control means A first pulse applying means for applying a plurality of pulses during one line cycle; and a second pulse applying a pulse having a width different from that of the first pulse applying means to the heating element during one line cycle. Pulse applying means.

Thus, the following effects can be obtained.

[0018] In the heating control means of the heating elements of the thermal head, the heating element a plurality of pulses for heating to a first temperature T _E is applied between the one-line period, the heating element during one line period applying a pulse of applied pulse and different widths of the first temperature T _E for heating to a second temperature T _P. Therefore, by controlling the applied pulse without providing an additional resistor, it is possible to optimize the printing quality of thermal paper and the like and the erasing quality of rewritable media.

In the thermal head driving method,
When the heating element is heated by the heating control means, the width of the pulse to be applied is controlled depending on whether the heating element has been heated before. For this reason, it is possible to prevent the effects of the previous coloring, decoloring, and the like.

Further, a plurality of pulses are applied to the heating element during one line cycle by the first pulse applying means of the heating control means of the heating element of the thermal head, and the heating element is applied to the heating element by the second pulse applying means. A pulse having a width different from the pulse of the first pulse applying means is applied during one line cycle. Therefore, it is possible to provide a thermal head driving device that optimizes the printing quality of thermal paper and the like, the erasing quality of rewritable media, and the like by controlling applied pulses without providing an additional resistor.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, high-temperature data and low-temperature data are created in advance using a binary input thermal head.
By applying several pulses to the heating element during one line cycle, the temperature reached by the heating element according to the number of pulses is controlled together with the application time to set the gradation. As a result, the processing speed is several times higher than that of a one-input thermal head. Further, at the expense of the processing speed, the processing can be performed by expanding the range of gradation several times, and the degree of freedom in pulse setting can be remarkably expanded.

Further, for a rewritable medium, by setting data other than data to be printed as erase data,
Concentrated pulses are applied to the print side to increase the maximum temperature reached to the rewritable media, and short pulses can be applied several times to the erase side at the same time. At the same time, the pulse setting becomes very easy.

(1) Description of Driving Method of Binary Input Thermal Head (Example of Rewrite Media) FIG. 1 is an explanatory diagram of a driving method of a binary input thermal head. In FIG. 1, rewrite media (rewrite paper)
Respect, T _P is defined which is higher temperatures for color development and decolorization temperature T _E which is at a low temperature of for decolorization.

There are a strobe (STR) q signal and a strobe (STR) Q signal for driving a heating element of a thermal head for a rewritable medium, and FIG. 1A is an explanation of the strobe (STR) q signal. 1 (a), the strobe (STR) q signal, the number of times between the erase pulses for the decoloring of the erasing temperature T _E to the heating time tau _ES and decoloring temperature holding time tau _EK, ON Becomes Incidentally, T ₂ indicates the ON period of the strobe q signal (one pulse). FIG. 1B illustrates the strobe (STR) Q signal. In FIG. 1 (b), a strobe (STR) Q signal is used for printing, and a printing pulse is generated by applying a color development time τ _PS + τ.
_PI , turn on. Incidentally, T ₁ indicates the ON period of the strobe Q signals. Therefore, τ _ED is decolorized cooling time, τ _PD
Is the color developing / cooling time, the one-line cycle is as follows at the minimum.

Minimum of one line cycle (decoloring pulse) =
τ _ES + τ _EK + τ _ED Minimum of one line cycle (coloring pulse) = τ _PS + τ _PI +
τ _PD Here, the strobe q signal and the strobe Q signal can be freely set within each line cycle, so that at the minimum of one line cycle, [τ _ES + τ _EK + τ _ED ] at the time of the decoloring pulse or
The longer of [τ _PS + τ _PI + τ _PD ] at the time of the coloring pulse.

(2) Comparison with the conventional example of one line cycle The following is a comparison of the present embodiment (FIG. 1) with the conventional example (FIG. 5) at the minimum time of one line cycle.

The minimum time of one line cycle in the present embodiment
At the time of the decoloring pulse_ES+ Τ_EK+ Τ _ED], When the color fades
Warm time τ_ED<Color development time τ_PD Therefore, in the present embodiment [(τ_ES+ Τ_EK) + Τ_ED] <Conventional example [(τ
_ES+ Τ_EK) + Τ_PI+ Τ _PD]: Color pulse is at the minimum of one line cycle in this embodiment.
(Τ_PS+ Τ_PI+ Τ _PD], The color erasing temperature T at the time of color development
_EHeating time τ up to_PSIs the decoloring temperature T when decoloring_EUp to
Warm time τ_ESIs approximately equal to (τ_PS≒ τ_ESIn this embodiment [τ_PS+ (Τ_PI+ Τ_PD)] <Conventional example [τ_ES
+ Τ_EK+ (Τ_PI+ Τ_PD)] As described above, the present embodiment is compared with the conventional example.
Thus, the line cycle can be shortened.

(3) Description of history control FIG. 2 is an explanatory diagram of a history control equivalent circuit, FIG. 3 is an explanatory diagram of a control signal, and FIG. 4 is an explanatory diagram of a history control logic.

(A): Description of hysteresis control equivalent circuit FIG. 2 (a) shows a control circuit (heating control means for the heating element) per dot of the thermal head. FIG. 2 (a)
1, 1 is an FET, 2, 29, 30, 31 are OR circuits, 3, 4, 5 (Gqn) are multi-input AND circuits, and 6 (G
Qn), 7 (GAn), 8 (GBn) are AND circuits, 9
15 to 15 are NAND circuits, 16 to 24 are inverters, 25 to 25
Reference numeral 28 denotes an EOR (exclusive sheave) circuit.

The FET 1 is a switching circuit whose output is connected to a heating element of the thermal head.

Also, as shown in FIG. 2B, dots Q1 (current data), Q2 (previous data), Q3 (previous data), LQ2 (left data), and RQ2 (right data) of the color temperature section. The signal indicating the presence or absence of the (previous data) is input as signals Q1, Q2, Q3, LQ2, and RQ2 shown in FIG.

The dot q in the decoloring temperature portion shown in FIG.
1 (current data), Q2 (data before color temperature), Q3
The signals indicating the presence / absence of (previous data before the coloring temperature), LQ2 (preceding data on the left side of the coloring temperature), and RQ2 (preceding data on the right side of the coloring temperature) are signals q1, Q2, and q2 shown in FIG.
It is input as Q3, LQ2, and RQ2.

The dot q in the decoloring temperature section shown in FIG.
A signal indicating the presence / absence of 1 (current data), q2 (previous data), and q3 (previous previous data) is a signal q shown in FIG.
It is input as 1, q2, q3.

Then, a strobe signal (STROBE)
Q is for heating the thermal head to the color development temperature and printing on the paper, and the strobe signal (STRO)
BE) q is for heating the thermal head to the decoloring temperature to erase the print on the paper.

Now, when printing the corresponding print Q1 shown in FIG. 2B, if there is no print data in Q2, Q3, LQ2, RQ2, these are "0", and the NAND circuits 9-1
2 output "1", and the AND circuit 6,
7, 8 and the multi-input AND circuit 3 all output "1", and the FET 1 thereby outputs a strobe signal (STROB).
E) turns on for time T ₁ defined by Q, heating the heating elements of the thermal head.

However, if there is print data in at least one of Q2, Q3, LQ2, and RQ2, the gate signals A1,
"0" is output from the AND circuit 6 for a time controlled based on B1, A2, and B2, and the strobe signal (ST
ROBE) Q is controlled so that the output time of “1” of the multi-input AND circuit 3 is shorter than T ₁ , and the strobe signal (STROBE) Q equalizes the energy of the heat generating portion including the heat generating element of the thermal head. Control.

When the corresponding dot q1 shown in FIG. 2C is erased, if there is no print data in Q2, Q3, LQ2 and RQ2, these are "0", and the NAND circuit 13
15 output "1", both the multi-input AND circuit 5 and the multi-input AND circuit 4 output "1", and the FET1 thereby outputs the strobe signal (STROB).
E) The FET 1 is turned on for each time T ₂ of a plurality of pulses determined by q to heat the heating element of the thermal head.

However, if there is print data in at least one of Q2, Q3, LQ2, and RQ2, the gate signals C1,
“0” is output from the AND circuit 4 for a time controlled based on C2 and C3, and the strobe signal (STROB) is output.
E) the output time of the "1" in the multi-input AND circuit 4 by q is controlled to be shorter than the T _2, is controlled so that the temperature of the heating elements of the thermal head are equal in the strobe signal (STROBE) q . When the corresponding dot q1 shown in FIG. 2D is erased, if there is no erase data in q2 and q3, these are "0", and all of the NAND circuits 13 to 15 output "1". Therefore, both the multi-input AND circuit 5 and the multi-input AND circuit 4 output “1”, and the FET 1 thereby outputs the strobe signal (STRO).
BE) to turn on each time T ₂ only FET1 defined by q, it heats the heating elements of the thermal head.

However, if there is decoloring data in at least one of q2 and q3, taking into consideration the heat storage effect, only the time controlled based on the gate signals C1, C2 and C3 according to this will be described later. aND circuit 4 is output is "0" controlled to be shorter than the output time the T ₂ of the "1" in the multi-input aND circuit 4 according to the strobe signal (sTROBE) q, a strobe signal (sTROBE)
Control is performed so that the temperatures of the heating elements of the thermal head in q become equal.

(B): Description of Control Signals The various control signals shown in FIG. 3 are output from a control signal output circuit (not shown), and are all output at the same cycle.

The control signals shown in FIG. 3A are various control signals (DAT) for controlling the thermal head at a high temperature.
A1 (Q)), and the control signals shown in (b) are various control signals (DATA2 (q)) for performing the erasing temperature state of the thermal head, ie, erasing control.

[0042] STROBEQ signal, the printing control range shown in FIG. 2 (b), when printing only the appropriate print dot Q1 dot is present, a thermal head connected thereto to turn on period T ₁ only FET1 is intended to heating control only for the period T _1, as shown in FIG. 3 (a), only for the period T ₁ is at a low level.

[0043] GATE A1 signal is, at the same time falls and STROBEQ signal, in which rises after a period t _1.

The GATE A2 signal falls at the same time as the STROBEQ signal, and rises after a period (t ₁ + t ₂ ).

The GATE B1 signal is a STROBEQ signal.
Period (t₁+ T _Two+ T_Three+ T_Four)rear
And then the period t_FiveLater, STROBEQ
It rises simultaneously with the issue.

The GATE B2 signal is a STROBEQ signal.
Period (t₁+ T _Two+ T_Three) Fall after
And then the period (t_Four+ T_Five) Later, STROBE
It rises simultaneously with the Q signal.

Further STROBEq signal, in the control range shown in FIG. 2 (d), if there is decolored data only to the relevant dot q1, only ON period T ₂ of the pulse FET
The connected thermal head thereto by 1 to turn on is intended to heating control only for the period T _2, as shown in FIG. 3 (b), the pulse of the ON period T ₂ by a low level.

[0048] GATE C1 signal is, at the same time falls and STROBEq signal, in which rises after a period t _6.

The GATE C2 signal falls at the same time as the STROBEq signal, and rises after a period (t ₆ + t ₇ ).

The GATE C3 signal falls at the same time as the STROBEq signal and rises after a period (t ₆ + t ₇ + t ₈ ).

These T ₁ , T ₂ , t _{1 to} t ₈ are:
It can be appropriately set according to the characteristics of the paper.

(C): Description of heat history control Based on FIGS. 2 and 3, the heat history control will be described with reference to FIG.
2D, the print data exists for the print dots Q1 to Q3, LQ2, and RQ2 in the color-developed portion, and the dots Q2, Q3, LQ2, and RQ2 exist in the decolored portion. , Q1 to q3, the case where data exists as described below will be described.

Here, when Q1 is the corresponding print dot,
Q2 indicates a print dot immediately before the one line, and Q3 indicates a print dot immediately before the two lines. LQ2 indicates the left print dot one line before, and RQ2 indicates the right print dot one line before.

When q1 is the corresponding decolored dot,
q2 indicates the decolored dot immediately before the one line, and q3 indicates 2
Indicates the erased dot immediately before the line.

(Description of Control in Coloring Section) (1) When print data exists only in print dot Q1, in the print control range shown in FIG. 2B, print data exists only in print dot Q1 and Q2 , Q3, LQ2,
When print data does not exist in RQ2, in FIG. 2A, Q1 = “1”, Q2 = “0”, Q3 = “0”, LQ2 =
"0", RQ2 = "0".

Each of these "0" s causes the NAND circuits 9 to 12
Output “1”, and the AND circuits 6 to 8 output “1”. Since a STROBEQ signal as shown in FIG. 3A is transmitted to the inverter 16, FIG.
"1" is output from the period T ₁ only multi-input AND circuit 3 shown in. At this time, since q1 = “0”, the multi-input AND circuit 4 outputs “0”.

As described above, since "1" output from the multi-input AND circuit 3 is input to the FET 1 via the OR circuit 2, the OR circuit 2 eventually has print data in Q1, Q2, Q3, LQ2, if there is no print data to RQ2, which was turned on by applying only the period T ₁ to "1" to the FET1, to controlling heat generation of the heating elements of the thermal head connected to FET1 only for the period T _1.

(2) When print data exists in the print dots Q1 and Q2, the corresponding print dot Q1 and the print dot Q2 one line before the print dot Q1
When print data exists in FIG. 2, Q1 and Q in FIG.
2 is applied with “1”, Q3 = “0”, LQ2
= “0”, RQ2 = “0” is applied. Thus, the NAND circuits 10 to 12 each output "1".

At this time, the NAND circuit 9 includes the inverter 1
8, the inversion of the GATE A1 signal shown in FIG.
Since the signal and Q2 = "1" are applied, the period in FIG.
Interval t ₁The NAND circuit 9 outputs “0” only during
"1" is output. Therefore, the multi-input AND circuit 3 is shown in FIG.
Period T shown in₁To period t₁After subtracting (t_Two
+ T_Three+ T_Four+ T_Five) Outputs “1” and FET1
Is turned on only during the period of
Change the heating element of the head to (T₁-T₁) Heat generation control only for a period
You.

(3) When print data exists in the print dots Q1 and LQ2, the print dot Q1 and the adjacent left front print dot LQ2
When print data exists in Q1, L1 and LQ in FIG.
2 are respectively applied with “1”, Q2 = “0”, Q3 =
“0” and RQ2 = “0” are applied. As a result, the NAND circuit 7 and the NAND circuits 9 and 10 each output "1".

At this time, LQ2 =
“1” and the output of the EOR circuit 25 are input. EO
The inverted signal of the GATE A1 signal shown in FIG.
At night, since the inverted signal of GATE A2 signal shown in FIG. 3 (a) is applied only during the period t ₂ shown in FIG. 3 EOR
The circuit 25 outputs “1”, and outputs “0” in other periods. Therefore, the NAND circuit 10 outputs “0” only during the period t _2, and outputs “1” during other periods.

Accordingly, the multi-input AND circuit 3 operates in the remaining period (t ₁ + t _{3) obtained} by subtracting the period t ₂ from the period T ₁ shown in FIG.
+ T ₄ + t ₅ ) outputs “1”, the FET 1 is also turned on only during this period, and the heating element of the thermal head connected to the FET _{1 is} controlled to generate heat only for the period (T ₁ −t ₂ ).

(4) When print data exists in the print dots Q1 and RQ2, the corresponding print dot Q1 and the print dot RQ2 immediately before and adjacent to the print dot Q1 are located.
When print data exists in Q1, RQ and RQ in FIG.
2 are respectively applied with “1”, Q2 = “0”, Q3 =
“0” and LQ2 = “0” are applied. Thus, the NAND circuits 9 to 11 each output "1".

At this time, the RQ2 =
“1” and the output of the EOR circuit 26 are input. EO
The R circuit 26 outputs the inverted signal of the GATE B1 signal shown in FIG.
According to, because the inverted signal of GATE B2 shown in FIG. 3 (a) is applied, EOR circuit 26 only for the period t ₄ when 3 outputs "1", other periods outputs "0" .
Therefore the NAND circuit 12 outputs only the period t ₄ "0", other periods outputs "1".

Therefore, the multi-input AND circuit 3 operates by subtracting the period t ₄ from the period T ₁ shown in FIG. 3 (t ₁ + t _2).
+ T ₃ + t ₅ ) outputs “1”, the FET 1 is also turned on only during this period, and the heating element of the thermal head connected to the FET _{1 is} controlled to generate heat only for the period (T ₁ −t ₄ ).

(5) When print data exists in the print dots Q1 and Q3, the corresponding print dot Q1 and the print dot Q3 two dots before the print dot Q1
When print data exists in Q1, Q1 and Q3 in FIG.
Are respectively applied, Q2 = “0”, LQ2 =
“0” and RQ2 = “0” are applied. Thereby, the NAND circuits 9, 10 and 12 each output "1".

At this time, Q3 = “1” is applied to the NAND circuit 11.
And GATE shown in FIG.
B1 Since the signal inverting signal and is applied, the period t ₅ only the NAND circuit 11 shown in FIG. 3 outputs "0", other periods outputs "1".

Accordingly, the multi-input AND circuit 3 operates in the remaining period (t ₁ + t _{2) obtained} by subtracting the period t ₅ from the period T ₁ shown in FIG.
+ T ₃ + t ₄ ) outputs “1”, the FET 1 is also turned on only during this period, and the heating element of the thermal head connected to the FET _{1 is} controlled to generate heat for the period (T ₁ −t ₅ ).

(6) When print data exists in the print dots Q1, Q2, and Q3, the corresponding print dot Q1 and the print dot Q2 immediately before the print dot Q1
When print data exists in the print dot Q3 two dots before that, "1" is applied to each of Q1, Q2, and Q3 in FIG. 2A, and LQ2 = "0" and RQ2 = "0" are applied. Is done. Thus, the NAND circuits 10 and 12 each output “1”.

At this time, Q2 = “1” is applied to the NAND circuit 9.
And GATE shown in FIG.
Since the inverted signal of the A1 signal is applied, the NAND circuit 9 outputs “0” only during the period t ₁ in FIG. 3, and outputs “1” during other periods. The NAND circuit 11 has Q
3 = “1” and the inverted signal of the GATE B1 signal shown in FIG.
Period t ₅ only the NAND circuit 11 shown in FIG. 3 outputs "0", other periods outputs "1".

Accordingly, the multi-input AND circuit 3 performs the remaining period (t) by subtracting the periods t ₁ and t ₅ from the period T ₁ shown in FIG.
₂ + t ₃ + t ₄₎ outputs "1", FET1 also only this time turned on, the heating elements of the thermal head connected to _{FET1 (T 1 -t 1 -t 5} ) that only heating control period.

(7) Print dots Q1, Q2, Q3, LQ
2. When print data exists in a plurality of print dots of RQ3, the corresponding print dot Q1 and print dots Q2, Q3, LQ
2, a plurality of print dots of RQ2, for example, Q2 and L
When print data exists in Q2, Q3 = "0", R
Since Q2 = “0”, the NAND circuits 11 and 12 each output “1”.

At this time, as shown in the above (2), the NAND circuit 9 uses the inverter 18 to generate the GA shown in FIG.
Since the TE A1 signal and Q2 = "1" are applied, FIG.
Only during the period t ₁ in the NAND circuit 9 outputs "0".

As shown in the above (3), LQ2 = "1" and the output of the EOR circuit 25 are input to the NAND circuit 10. Since the inverted signal of the GATE A1 signal shown in FIG. 3A by the inverter 18 and the inverted signal of the GATE A2 signal shown in FIG. 3A by the inverter 19 are applied to the EOR circuit 25, FIG. period t ₂ only EOR circuit 25 shown in the "1" outputs, other periods "0"
Is output. Therefore, NAND circuit 10 outputs only the period t ₂ "0".

Therefore, when print data exists in Q2 and LQ2, and when data exists in the corresponding print dot Q1 and print dot Q2, the period t during which the AND circuit 6 outputs "0"
₁ and a period t during which the AND circuit 6 outputs "0" when data exists in the corresponding print dot Q1 and print dot LQ2.
_The AND circuit 6 outputs “0” for the sum of (t ₁ + t ₂ ) and the heating control of the heating element of the thermal head connected to the FET ₁ by (T ₁ −t ₁ −t ₂ ).

That is, when print data is present in the print dot Q1 and a plurality of print dots among the print dots Q2, Q3, LQ2, and RQ2, the print dot Q1 and other print dots Q2, Q3, LQ2, RQ2 When there is data in the print dot and the AND circuit 6, according to the other print dots, the AND circuit 6 changes "0" by the sum of the periods of "0" described in the above (2) to (5). The heating element of the thermal head connected to the FET ₁ is heated for a period obtained by subtracting T1 from the output for the sum of these outputs.

For example, Q1, Q2, Q3, LQ2, RQ
When all of the 2 printing data is present, T ₁ - (t <sub>1
+ T 2 + t 4 + t</sub> 5) = t by the AND circuit 6 period of ₃ outputs "1" to heat the heating element connected to the thermal head only FET1 this period t _3.

(Description of Unique Control in Decoloring Section) (8) When print data exists only in the print dot q1, in the print control range shown in FIG. If there is no decoloring data in q2 and q3, in FIG. 2A, q1 = “1”, q
2 = “0” and q3 = “0”.

Therefore, since q2 = "0" and q3 = "0", "1" is output to each of the NAND circuits 13, 14, and 15, the multi-input AND circuit 5 outputs "1". At this time, q1 = “1”, and the inverter 17 shown in FIG.
Since the STROBEq signal as shown in FIG.
(B) only the period T ₂ showing "1" from the multi-input AND circuit 4 is outputted. At this time, since Q1 = “0”, the multi-input AND circuit 3 outputs “0”.

As described above, since “1” output from the multi-input AND circuit 4 is input to the FET 1, F 1
ET1, it is decolored data q1, q2, q3 when no decoloring data, which is turned on by applying only the period T ₂ to "1" to the FET1, heating elements of the thermal head connected to FET1 There is heating control only for the period T _2.

(9) When decoloring data exists in decoloring dots q1 and q2, the corresponding decoloring dot q1 and decoloring dot q2 one line before that
In FIG. 2A, when decolored data exists, q1 and q
"1" is applied to each of 2 and q3 = "0" is applied. Thus, the NAND circuits 14 and 15 output “1”.

[0082] The NAND circuit 13 at this time, the inverter 22, since FIG. 3 (b) the inverted signal of the GATE C1 signal shown in the q2 = "1" is applied, only during the period t ₆ in FIG. 3 NAND The circuit 13 outputs "0", and the other outputs "1". AND circuit 5 therefore rest period minus the period t ₆ from the period T ₂ shown in FIG. 3 (t ₇ + t
₈ + t ₉ ) outputs “1”, and the multi-input AND circuit 4 and the OR circuit 2 also output “1” during this period (t ₇ + t ₈ + t ₉ ).
Is output, FET1 is also turned on only during this period,
The heating element of the thermal head connected to FET1 is (T ₂
Heat generation is controlled only for a period of -t ₆ ).

(10) When decoloring data exists in the decoloring dots q1 and q3, the corresponding decoloring dot q1 and the decoloring dot q3 two dots before the decoloring dot q1
In FIG. 2A, when decolored data exists, q1 and q
3 is applied with “1” and q2 = “0” is applied. Thus, the NAND circuits 13 and 15 output “1”.

At this time, in the NAND circuit 14, q3 =
“1” and the output of the EOR circuit 27 are input. EO
The R circuit 27 includes an inverted signal of the GATE C1 signal shown in FIG.
According to, since the inversion signal of the GATE C2 signal shown in FIG. 3 (b) is applied, "1" of the two signals, only EOR circuit 27 period t ₇ shown in FIG. 3 does not match the "0" and "1"
And outputs “0” in other periods. Therefore the NAND circuit 14 outputs only the time t ₇ "0", other periods outputs "1".

Therefore, the multi-input AND circuit 5 operates by subtracting the period t ₇ from the period T ₂ shown in FIG. 3 (t ₆ + t _8).
+ T ₉ ) outputs “1”, and the multi-input AND circuit 4 and the OR circuit 2 also output “1” only during this period (t ₆ + t ₈ + t ₉ ).
The heating element of the thermal head connected to ET1 is (T ₂ −
t ₇₎ is a period by the heat controlling.

(11) When decoloring data exists in decoloring dots q1, q2, and q3, the corresponding decoloring dot q1 and the decoloring dot q one dot before it
When decoloring data exists in both the decoloring dot q3 and the decoloring dot q3 two dots before that, q1, q2, q3 in FIG.
Is applied to each of them.

At this time, as shown in (9), the inverted signal of the GATE C1 signal shown in FIG. 3B and q2 = “1” are applied to the AND circuit 13 by the inverter 22. 3 and the NAND circuit 1 only during the period t ₆
3 outputs "0".

As shown in the above (10), the NAND circuit 1
4, q3 = “1” and the output of the EOR circuit 27 are input. At this time, the EOR circuit 27 includes the inverter 2
2 and the inverted signal of the GATE C1 signal shown in FIG.
Since the inverted signal of the TE C2 signal is applied, "1" of the two signals, EOR circuit 27 only for the period t ₇ shown in FIG. 3 does not match the "0" outputs "1", the other periods ""0" is output. Therefore the NAND circuit 14 outputs only the time t ₇ "0", other periods outputs "1".

Therefore, the multi-input AND circuit 5 shown in FIG.
Period T_TwoTo period t₆And t₇Remaining time t minus₈+
t₉Outputs “1”, and the multi-input AND circuit 4 and the OR
Road 2 is also in this period t₈+ T₉Only "1" is output,
FET1 is also in this period t₈+ T ₉= T_Two− (T₆+ T₇)
Only the thermal head connected to FET1
Heating element during this period T_Two− (T₆+ T₇) Only heat generation control
Is done.

(Explanation of Influence of High-Temperature Area on Decoloring Dot q1) Next, as shown in FIG.
The color dots Q2 and Q3 and the adjacent color dot of the preceding one line are defined as LQ2 and RQL2.

Hereinafter, the corresponding decoloring dot q of the decoloring part when color data exists in LQ2 and RQ2 in FIG.
A typical control for No. 1 will be described.

(12) When data exists in the decoloring dots q1 and LQ2, in the control range of the decoloring section shown in FIG. 2D, only the corresponding decoloring dot q1 has data and q2 and q3 have data. In the case where there is no data in the dots LQ2 of the coloring portion shown in FIG. 2C and no data in Q2, Q3, and RQ2 shown in FIG.
In (a), q1 = “1”, q2 = “0”, q3 =
“0”, Q2 = “0”, Q3 = “0”, LQ2 =
"1", RQ2 = "0".

At this time, since q2 = "0" and Q2 = "0", the NAND circuit 13 outputs "1", and q3 = "0" and Q3
Since 3 = “0”, the NAND circuit 14 outputs “1”.

Since LQ2 = "1", the NAND circuit 15
"1" is applied to one input circuit, and the output of the EOR circuit 28 is input to the other input circuit. Then E
The OR circuit 28 outputs an inverted signal of the GATE C2 signal shown in FIG.
3B, the inverted signal of the GATE C3 signal shown in FIG. 3B is applied, and therefore, the EOR circuit 28 does not match “1” and “0” of both signals during the period t ₈ shown in FIG. 3B.
Outputs “1”, and outputs “0” in other periods. Therefore the NAND circuit 15 outputs "0" only for the period t _8, other periods outputs "1".

Therefore, the multi-input AND circuit 5 is shown in FIG.
Each period T by STROBEq signal _TwoTo period t₈Pull
Remaining period (t₆+ T₇+ T₉) Outputs "1"
Then, the multi-input AND circuit 4 and the OR circuit 2 also operate during this period (t
₆+ T₇+ T₉) = T_Two-T₈Only output "1"
Thus, FET1 is also turned on only during this period, and is connected to FET1.
The heating element of the continued thermal head_Two-T₈)
Heat generation is controlled only during the period.

[0096] By shortening the only heating time period t ₈ in this manner, it is possible to prevent heat accumulation effect in the dot LQ2 coloring portion for the corresponding decoloring dots q1.

(13) When data exists in the dots q1 and RQ2, in the control range of the decoloring section shown in FIG. 2D, data exists only in the decoloring dot q1, and print data is stored in q2 and q3. In the case where there is no data in the dots RQ2 of the color forming portion shown in FIG. 2C and no data in Q2, Q3 and LQ2 shown in FIG. 2C, in FIG. 2A, q1 = “1”, q2 = “0”, q3
= "0", Q2 = "0", Q3 = "0", LQ2 =
"0", RQ2 = "1".

At this time, since q2 = "0" and Q2 = "0", the NAND circuit 13 outputs "1" and q3 = "0" and Q3
Since 3 = “0”, the NAND circuit 14 outputs “1”.

Since RQ2 = "1", the NAND circuit 15
"1" is applied to one input circuit, and the output of the EOR circuit 28 is input to the other input circuit. Thus as in the case where print data exists in the print dot q1 and LQ2 of the (12) only during the period t ₈ shown in FIG. 3 (b) EO
R circuit 28 outputs "1", the other period, the outputs "0", the heating element of the thermal head connected to FET1 is only heating control (T ₁ -t ₈₎ period.

Thus, by shortening the heating time by the period t _8, it is possible to prevent the effect of heat accumulation on the dot RQ 2 in the high-temperature portion with respect to the print dot q 1.

(14) When data exists in the dot q1, LQ2, and RQ2, in the control range of the decoloring section shown in FIG. 2D, there is data only in the dot q1 and data in q2 and q3. However, the coloring dots LQ2 and RQ in the high temperature area shown in FIG.
When there is data in Q2 and no data in Q2 and Q3, in FIG. 2A, q1 = "1", q2 = "0", q3
= "0", Q2 = "0", Q3 = "0", LQ2 =
“1”, LQ2 = “1”.

At this time, the print dots q1 and L
As in the case where print data exists in Q2, FIG.
The EOR circuit 28 outputs “1” only for the period t ₈ shown in FIG.
Other periods outputs "0", the heating element of the thermal head connected to FET1 is only heating control (T ₂ -t ₈₎ period.

Thus, by shortening the heating time by the period t _8, it is possible to prevent the effect of heat accumulation on the color dots LQ2 and RQ2 in the high temperature portion with respect to the dot q1.

(15) When print data exists in the dots q1, Q2, and LQ2, in the control range of the decoloring section shown in FIG. 2D, data exists only in the corresponding dot q1, and data exists in the q2 and q3. Color dots Q2 and LQ in the high temperature area shown in FIG.
2 has no data in Q3 and RQ2, q1 = “1”, q2 = “0”, q3 =
“0”, Q2 = “1”, LQ2 = “1”, Q3 =
"0", RQ2 = "0".

At this time, since q3 = "0" and Q3 = "0", the NAND circuit 14 outputs "1". However, in the NAND circuit 13, although q2 = "0", Q2 = "1" is input to the signal input circuit of q2 via the OR circuit 29. Further by the inverter 22 to the NAND circuit 13, the inverted signal of the GATE C1 signal shown in FIG. 3 (b) is applied, the NAND circuit 13 only during the period t ₆ in FIG. 3 (b) to "0" The other outputs "1".

Since LQ2 = "1", the OR circuit 31
, "1" is applied to one input circuit of the NAND circuit 15 and the output of the EOR circuit 28 is input to the other input circuit. At this time, the inverter 2 is connected to the EOR circuit 28.
3 and the inverted signal of the GATE C2 shown in FIG.
Since the inverted signal of the C3 signal is applied, “1” and “0” of both signals do not coincide with each other, and the period t shown in FIG.
_The EOR circuit 28 outputs “1” by ₈ and outputs “0” in other periods. Therefore, the NAND circuit 15 operates in the period t ₈
Only "0" is output, and "1" is output during other periods.

Accordingly, the multi-input AND circuit 5 is arranged as shown in FIG.
The remaining period (t ₇ + t ₉ ) obtained by subtracting the periods t ₆ and t ₈ from the period T ₂ by the STROBEq signal shown in FIG.
And the multi-input AND circuit 4 and the OR circuit 2 also output “1” during this period (t ₇ + t ₉ ) = T ₂ − (t ₆ + t ₈ ).
The heating element of the thermal head connected to ET1
_2- (t ₆ + t ₈ )].

In this way, by shortening the heating time by the period (t ₆ + t ₈ ), it is possible to prevent the effect of heat storage on the color dots Q2 and LQ2 in the high temperature portion with respect to the corresponding print dot q1.

(16) When data exists in the dots q1, Q3, and LQ2, in the control range of the decoloring section shown in FIG. 2D, data exists only in the corresponding dot q1, and data exists in q2 and q3. However, the color dots Q3 and LQ in the high-temperature portion shown in FIG.
2 has no data in Q2 and RQ2, in FIG. 2A, q1 = “1”, q2 = “0”, and q3 =
“0”, Q2 = “0”, Q3 = “1”, LQ2 =
"1", RQ2 = "0".

At this time, since q2 = "0" and Q2 = "0", the NAND circuit 13 outputs "1". However, in the NAND circuit 14, although q3 = "0", Q3 = "1" is input to the signal input circuit of q3 via the OR circuit 30. Further, the output of the EOR circuit 27 is input to the other input circuit of the NAND circuit 14. At this time, the EOR circuit 27 uses the inverter 22 to generate G as shown in FIG.
An inverted signal of the ATE C1 signal, the inverted signal of the GATE C2 signal shown in FIG. 3 (b) by the inverter 23 is applied, does not match the two signals, only for the period t ₇ shown in FIG. 3 (b) EOR The circuit 27 outputs “1”, and outputs “0” in other periods. Therefore it outputs "0" only for the period t ₇ of the NAND circuit 14, other periods outputs "1".

[0111] Further LQ2 = dot q1 and the NAND circuit 15 as illustrated when data exists in LQ2 outputs only period t ₈ "0", the other period of the (12) for "1""1" is output.

Accordingly, the multi-input AND circuit 5 is arranged as shown in FIG.
The remaining period (t ₆ + t ₉ ) obtained by subtracting the periods t ₇ and t ₈ from the period T ₂ by the STROBEq signal shown in FIG.
And the multi-input AND circuit 4 and the OR circuit 2 also output “1” during this period (t ₆ + t ₉ ) = T ₂ − (t ₇ + t ₈ ).
The heating element of the thermal head connected to ET1
₂₋ (t ₇ + t ₈ )].

In this way, by shortening the heating time by the period (t ₇ + t ₈ ), it is possible to prevent the effect of heat storage on the coloring dots Q3 and LQ2 in the high-temperature portion with respect to the corresponding decoloring dot q1.

In other cases, the control circuit shown in FIG. 2A can prevent the adverse effect of the print dots in the high energy area.

As described above, according to the present invention, color control and color erasure control can be performed very accurately, so that accurate printing can be performed even when data of color development and color erasure are mixed.

In the above description, the embodiment for color development and decoloration (two temperatures of high and low) has been described. However, the present invention is not limited to this.
Green and black, other combinations, and combinations of three or more colors are possible. Further, the STROBEQ signal may be composed of a plurality of pulses, and history control may be performed on each pulse.

(D): Explanation by Logical Table FIG. 4 is an explanatory diagram of the history control logic, and FIG. 4 (a) is an explanation of the logical table. In FIG. 4A, as input, S
TROBEQ, STROBEq, current color development data Q1,
The decoloring current data q1 is shown, and the outputs of GQn (AND circuit 6) and Gqn (AND circuit 5) are shown as partial outputs,
DOn is shown as the output of FET1.

For example, if the signal of STROBEQ is "*"
(* Indicates either “0” or “1”), the signal of STROBEq is “0”, the current coloring data Q1 is “0”, the current decoloring data q1 is “1”, and GQn
When the output of (AND circuit 6) is “*” and the output of Gqn (AND circuit 5) is “1”, the output DOn is “O”.
N ".

For example, if the signal of STROBEQ is "0",
The signal of STROBEq is "0", the current coloring data Q1 is "0", the current decoloring data q1 is "0", the output of GQn (AND circuit 6) is "*", and the output of Gqn (AND circuit 5) is "0". In the case of “*”, the output DOn is “OFF”.

FIG. 4B illustrates the GQn output.
In FIG. 4B, outputs of GAn (AND circuit 7) and GBn (AND circuit 8) are shown as partial outputs, and outputs of GQn (AND circuit 6) are shown as outputs.

For example, when the output of GAn (AND circuit 7) is “1” and the output of GBn (AND circuit 8) is “1”, it indicates that the output of GQn (AND circuit 6) is “1”. I have. Also, for example, GAn (AND circuit 7)
The output is "0" and the output of GBn (AND circuit 8) is "1".
Indicates that the output of GQn (AND circuit 6) is "0".

FIG. 4C illustrates the output of the GAn.
In FIG. 4C, GATE A1, GA
A signal of TE A2 is shown, and Q is used as data (DATA).
2, LQ2, and GAn (AND circuit 7) as output
Shows the output.

For example, if the signal of GATE A1 is "0",
When the signal of GATE A2 is “0”, the data Q2 is “0”, and the data LQ2 is “*”, it indicates that the output of the GAn (the AND circuit 7) is “1”. Further, for example, when the signal of GATE A1 is “0”,
When the signal of A2 is “1”, the data Q2 is “0”, and the data LQ2 is “1”, it indicates that the output of the GAn (the AND circuit 7) is “0”.

FIG. 4D illustrates the GBn output.
In FIG. 4D, GATE B1, GA
A signal of TE B2 is shown, and Q is used as data (DATA).
3, RQ2, and GBn (an AND circuit 8) as an output
Shows the output.

For example, if the signal of GATE B1 is "0",
When the GATE B2 signal is “0”, the data Q3 is “0”, and the data RQ2 is “*”, it indicates that the output of the GBn (AND circuit 8) is “1”. Further, for example, when the signal of GATE B1 is “0”,
When the signal of B2 is “1”, the data Q3 is “0”, and the data RQ2 is “1”, it indicates that the output of the GBn (AND circuit 8) is “0”.

FIG. 4E is an explanation of the Gqn output.
In FIG. 4 (e), GATE C1, GA
TEC C2 and GATE C3 signals, and data (D
ATA) indicates Q2 or q2, Q3 or q3, LQ2 or RQ2, and the output indicates the output of Gqn (multi-input AND circuit 5).

For example, if the signal of GATE C1 is "0",
When the signal of GATE C2 is “0”, the signal of GATE C3 is “0”, and the data Q2 or q2 is “0”, the data Q3 or q3 is “*”, and the data LQ2 or RQ2 is “*”, Gqn This indicates that the output of the (multi-input AND circuit 5) is "1". GATE C1
Signal is “0”, GATE C2 signal is “*”, GA
The signal of TEC3 is "*" and the data Q2 or q2
Is “1”, data Q3 or q3 is “*”, data LQ2
Or, when RQ2 is “*”, it indicates that the output of Gqn (multi-input AND circuit 5) is “0”.

As described above, by using the binary simultaneous input thermal head, the pulse setting for erasing and coloring can be divided and processed at the same time, so that the line cycle can be shortened as compared with the prior art. Thus, it is possible to cope with an increase in the speed of the printing apparatus.

[0129]

According to the present invention, the following effects can be obtained.

(1): The heating control means for the heating element of the thermal head applies a plurality of pulses for heating the heating element to the first temperature during one line cycle, and the heating element is heated for one line cycle. In order to apply a pulse having a width different from the applied pulse of the first temperature in order to heat to the second temperature in between, the applied pulse is controlled without providing an additional resistor, thereby printing on thermal paper or the like. It is possible to optimize the quality and the erasing quality of the rewrite media.

(2): When heating the heating element by the heating control means, depending on whether the heating element has been heated before,
Since the width of the pulse to be applied is controlled, it is possible to prevent the effects of the previous coloring and decoloring.

(3): A plurality of pulses are applied to the heating element during one line cycle by the first pulse applying means of the heating control means of the heating element of the thermal head, and the heating is performed by the second pulse applying means. In order to apply a pulse having a width different from that of the first pulse applying means to the body during one line cycle,
By controlling the applied pulse without providing an additional resistor, it is possible to provide a thermal head drive device that optimizes the printing quality of thermal paper and the like and the erasing quality of rewritable media.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a binary input thermal head driving method according to an embodiment.

FIG. 2 is an explanatory diagram of a history control equivalent circuit in the embodiment.

FIG. 3 is an explanatory diagram of a control signal in the embodiment.

FIG. 4 is an explanatory diagram of history control logic according to the embodiment.

FIG. 5 is an explanatory diagram of a conventional one-input thermal head driving method.

[Explanation of symbols]

T _E first temperature (decoloring temperature) T _P second temperature (color temperature) Strq strobe signal on a pulse period T ₂ decoloring strobe signal T ₁ color of strobe signals STRQ color for decoloring Strobe signal on pulse period

Claims (3)

[Claims] 1. A heating element of a thermal head that heats a printing object to be heated, and heating control means for heating the heating element at a plurality of different temperatures, wherein the heating control means controls the heating element by one line. A plurality of pulses are applied to heat the heating element to a first temperature during a cycle, and a pulse having a width different from the applied pulse of the first temperature to heat the heating element to a second temperature during a one-line cycle. And a method of driving a thermal head. 2. The method according to claim 1, wherein the heating control means heats the heating element by determining whether the heating element has been heated before.
2. The method according to claim 1, wherein a width of the applied pulse is controlled. 3. A heating element of a thermal head for heating a printing object to be heated, and heating control means for heating the heating element at a plurality of different temperatures, wherein the heating control means has one line for the heating element. First pulse applying means for applying a plurality of pulses during a cycle, and second pulse applying for applying a pulse having a width different from that of the first pulse applying means to the heating element during one line cycle. And a means for driving a thermal head.