JP2003154697A - Printer and preheat controlling method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermal transfer printer with a preheat control which can execute printing without a change in a print quality such as faint or thick printing. SOLUTION: In the thermal transfer printer with the preheat control, a thermal head 2 conducts printing on paper or the like by heating a plurality of heaters to a prescribed temperature or above and a control means 9 stores printing data and conducts a heating control on the basis of the printing data, for each control unit of the heaters, with the heaters in a plurality made one control unit respectively. A temperature acquiring means 4 detects the temperature of the thermal head and a heating time acquiring means 5 acquires the quantity of preheat required for heating the heaters to a temperature not high enough for printing, on the basis of the temperature detected by the temperature detecting means and by converting this quantity into a heating time or the like. After printing by the heaters is conducted, heating for preheat and heating for printing are executed alternately for the heaters not conducting heating, on the basis of the heating time or the like acquired by the heating time acquiring means 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applicable to printing by alternately transferring a strobe signal having a pulse width for heating a thermal head to a temperature at which printing is not performed and a strobe signal having print data to be actually printed. The present invention relates to a print control method for a thermal transfer printer capable of preventing the change in speed of the printer.

[0002]

2. Description of the Related Art Printing by a thermal transfer printer, a facsimile or the like has been conventionally known as one for performing thermal transfer or thermal paper printing. In these thermal transfer printers, facsimiles and the like, when printing, the head portion must have a predetermined temperature (for example, 20 ° C. to 25 ° C.) at which printing is performed. Therefore, the thermal head is heated so that the temperature does not reach printing so that printing can be started quickly. Such preheating of the thermal head is performed by the "preheating method of the thermal head" in JP-A-7-68827, the "printing device" in JP-A-9-70992, and the "heat storage control function" in JP-A-9-314886. Are disclosed in "Thermal printer having the". In these techniques, when the print data is generated, it is not necessary to heat the head portion of the non-printed portion, so the temperature of the head becomes low. When print data is suddenly sent to the head, it takes time to heat up to a predetermined temperature required for printing, so that the head is always preheated to a temperature at which printing is not achieved.

[0003]

However, if the thermal head is constantly heated to a temperature at which printing is not possible as described above, there is a problem that power consumption increases, so that the head that is performing printing does not work. Was preheated only. Therefore, the temperature of the head where printing is not performed drops, and when print data is suddenly sent to that head, the temperature of the head is low, so it takes time to reach the temperature required for printing. There is a problem in that printing is temporarily interrupted and the printing speed is partially slowed and printing cannot be performed at a constant speed.

The present invention has been devised in view of the above-mentioned problems of the prior art, and it is possible to transfer heat to a thermal transfer paper or to apply heat to the thermal head to the extent that heat is not sensed and to perform printing alternately. Due to this, even if printing is suddenly started on a part that was not printed until now, the head of that part is also preheated to a temperature that does not reach printing,
An object of the present invention is to provide a print control method for a thermal transfer printer that can perform printing without reducing the printing speed.

[0005]

To achieve the above object, the invention according to claim 1 of the present application has the following configuration. That is, a thermal head having a plurality of heating elements, which prints on a sheet by heating the heating elements to a predetermined temperature or higher, stores print data, and controls heating of the heating element based on the print data. A plurality of heating elements as one control unit, control means for each heating element for each control unit, temperature detecting means for detecting the temperature of the thermal head, and temperature detection means for detecting temperature. A heating time obtaining means for obtaining the amount of preheat necessary for heating the heating element to a temperature which does not reach printing and converting it into a heating time. A printer, wherein heating for preheating is performed on all heating elements that have not generated heat, based on the heating time acquired by the heating time acquisition means.

The invention according to claim 2 has the following configuration. That is, the printer according to claim 1, wherein the preheating is performed for each heating element for each control unit.

The invention according to claim 3 has the following configuration. That is, a thermal head having a plurality of heating elements, which prints on a sheet by heating the heating elements to a predetermined temperature or higher, stores print data, and controls heating of the heating element based on the print data. A plurality of heating elements as one control unit, control means for each heating element for each control unit, temperature detecting means for detecting the temperature of the thermal head, and temperature detection means for detecting temperature. In a printer having a heating time acquisition means for converting the amount of preheat required to heat the heating element to a temperature that does not reach printing, the heating time acquiring means converts the preheating amount to a temperature such as a heating time. Printer for preheating, based on the heating time and the like acquired by the heating time acquisition means, for all heating elements that did not generate heat Preheat control method.

The invention according to claim 3 has the following configuration. That is, the preheating control method for a printer according to claim 3, wherein the preheating is performed for each heating element for each control unit.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below in detail with reference to the drawings. Figure 1
FIG. 3 is a block configuration diagram of a thermal transfer printer for realizing preheating control according to the present invention. In FIG. 1, 1 is printer control means, 2 is a thermal head, 3 is a thermistor that detects the temperature of the thermal head 2, and 4 is a temperature that is an analog value detected by the thermistor 3 and is converted into a digital value temperature. A temperature acquisition means for acquiring 5, a heating time acquiring means for detecting a time for heating the thermal head 2 based on the acquired temperature, and a reference temperature for calculating a heating time in the heating time acquiring means 5. A conversion table, 7 is print data storage means for storing print data sent to the thermal transfer printer, and 8 is a print instruction and a preheat instruction for the thermal transfer printer based on the print data stored in the print data storage means 7. It is a printing means to give.
Further, 9 is a microprocessor (CPU) for controlling heating for printing and preheating of the thermal transfer printer 1,
It is a control unit having a ROM 9a and a RAM 9b as memories.

The thermal head 2 prints on a heat-sensitive paper which changes its color to a predetermined color when heat of a predetermined temperature is applied. Inside the head, a heating resistor for heating to a predetermined temperature is used for printing. A plurality of (resistors) are provided.
This heating resistor is temperature-controlled so that the thermal head 2 does not exceed a predetermined temperature. Since the thermal head 2 is provided with a plurality of heating resistors, it consumes a large amount of electric power when heated at the same time. Therefore, heating of the heating resistors is instructed by being divided into a plurality of signals. .

Further, when printing or the like, if the heating elements of the respective thermal heads 2 are heated at the same time, the electric power required at one time becomes large, and in this case, a large amount of electric power is consumed. Therefore, power supply components and control components also require large-capacity and expensive components. Therefore, in the present embodiment, when printing is performed, a method is employed in which the heating elements in one head are divided into a plurality of parts and controlled. That is, a set of the divided minute heating elements is used as one control unit, and a signal for heating (strobe signal) and the strobe signal and a latch register to be described later are slightly different for each control unit. Based on the heat generation instruction data based on the written print data, power is supplied to a predetermined heat generating resistor to generate heat.
With such a control method, the power required at one time is reduced.

The thermistor 3 is a temperature sensor for detecting the temperature of the thermal head 2. As described above, a predetermined current is flowing through the resistor provided inside the thermal head 2, and When the ambient temperature rises, its resistance value changes, and the temperature is detected by the voltage value that changes accordingly. In order to alternately perform printing and preheating based on the temperature of the thermal head 2 detected by the thermistor 3, if print data exists,
It becomes possible to obtain the temperature difference required for the temperature up to printing or the temperature below printing. The relationship between the temperature and the resistance value of the resistor provided in the thermistor 3 can be obtained by the following equation (Equation 1).

[0013]

[Formula 1] R _T = R ₀ e ^{B (1 / T-1 / T0)} (Formula 1) where R _T : resistance value at temperature T (K) R ₀ : temperature T0 (K) Resistance value at: T: Absolute temperature B: Thermistor constant e: Base of natural logarithm

The temperature acquisition means 4 is for obtaining the temperature of the thermal head 2 detected by the thermistor 3. In the present embodiment, the temperature data based on the analog voltage value detected by the thermistor 3 is converted into a digital value. It is also an A / D conversion means for converting into temperature data of. That is, by converting the voltage value detected by the thermistor 3 with a resolution of 2 ⁿ , an n-bit digital value is obtained. FIG. 2 is an explanatory diagram showing how a temperature based on an analog voltage value is converted into a digital value. As shown in FIG. 2, for example, when the voltage value input to the temperature acquisition unit 4 (A / D conversion) is 0.5 V (volt), the digital value “10” is displayed.
2 "is obtained, and the digital value" 512 "is obtained when the voltage is 2.5V (volt), and the digital value" 1024 "is obtained when the voltage is 5V (volt).

The heating time acquisition means 5 obtains in advance, by using an approximate curve, what the temperature of the head is, what degree the pulse width of the heating time is (the time during which the strobe signal is continuously supplied as a pulse). The pulse width required for preheating is empirically determined by experiments and the like. For example, the thermal transfer printer is arranged in a constant temperature state where the temperature is constant and is operated at each high temperature, normal temperature and low temperature. In this state, printing is performed by changing the pulse width, and the relationship between the printing state, the head temperature, and the pulse width can be obtained based on the experimental results. FIG. 3 is an explanatory diagram of a graph showing the relationship between the head temperature and the pulse width, which is derived from the experimental results and the like. As shown in FIG. 3, when the head temperature is plotted on the horizontal axis and the pulse width is plotted on the vertical axis, the pulse width relationship in which the pulse width gradually decreases as the head temperature increases is represented by an approximated curve W. It is possible to obtain the pulse widths P1, P2, P3, P4, ... For example, for P1, it is possible to preheat at time T1 in FIG. 3, and the maximum and minimum values of the strobe width that do not result in printing are shown. That is, how much heat (pulse width) should be applied to each head temperature to obtain the heat necessary for printing.

That is, the resistance value of the thermistor 3 is obtained from the equation 1, the head temperature is obtained from the voltage based on this resistance value (see FIG. 2), and the head temperature and the graph of FIG. 3 (FIG. 4).
It is possible to obtain the pulse width by searching the temperature conversion table of (1), and how long the head temperature can be heated (pulse width) to reach the temperature at which printing cannot be achieved. . This data is stored in the control means 1 as a data table.

The temperature conversion table 6 stores the pulse width calculated by the heating time acquisition means 5 for the n-bit digital value obtained by the temperature acquisition means 4. FIG. 4 is an explanatory diagram of the temperature conversion table 6 showing the pulse width for such a digital value. As shown in FIG. 4, for example, when the digital value is "0" or "1",
Strobe width is "10" (ms), digital value is "2"
Or, when it is "3", the strobe width is "9.9" (m
s), ..., When the digital value is "512", the strobe width is "4.7" (ms) and the digital value is "102".
When it is "4", the strobe width is "0".

The print data storage means 7 stores print data for one line sent to the thermal transfer printer,
The print data is temporarily stored in the latch register from the shift register when receiving the latch signal, and transferred to the thermal head 2 when receiving the strobe signal, and the thermal head generates heat for the time given as the pulse of the strobe signal. .

The printing means 8 is the print data storage means 7
The print data is read from the printer, and is a preheating unit that gives a preheat instruction to the head before or after printing. Then, the printing means 8 instructs the thermal head to alternately perform heating and preheating required for printing when print data exists.

That is, the printing means 8 outputs the preheating strobe signal in which the preheating pulse width is set to the thermal head 2 in the unprinted portion and the printing strobe signal in which the print data is set. The data is alternately transferred to the thermal head 2. FIG. 5 shows that the printing means 8
6 is a time chart showing a state in which preheating and heating required for printing are alternately performed. In FIG. 5, L1 indicates printing for one line, (1) is clock, (2) is data, (3) is latch, (4) is strobe, C1-1 is preheat amount, and C1 is
-2 is the print amount. In C1-1 of the preheat portion, T1
Indicates the latch time, T2 indicates the preheating time, and in C1-2 of the print portion, T3 indicates the latch time and T4 indicates the print time.

As shown in FIG. 5, C in the first cycle L1
In order to perform preheating as 1-1, for example, “L (ON)” is sent to the entire print data to prepare for data printing. In this case, since the data to print is not set,
When the pulse width of the preheating time is set and transferred to the strobe signal, printing is not actually performed and the heating resistor is preheated to the extent that the thermal paper does not heat. Next, as C1-2 of the first cycle L1, print data for printing is taken out from the print data storage means 7 and set, and data printing is prepared. In this case, the strobe signal is set with a pulse width for printing and is transferred. In this way, preheating (C1-1) and heating required for printing (C1-2) as the first cycle L1, alternating preheating (C2-1) and heating required for printing as the second cycle, ... By repeating the above, the thermal head 2 is always heated to a temperature below the print level, and even if print data is suddenly set in any of the heads, the thermal head 2 is immediately heated to a printable temperature. Can be heated
It is possible to print quickly without reducing the printing speed.

Next, a second embodiment of the printing speed control method for the thermal transfer printer according to the present invention will be described.
In the second embodiment, it is described that the print control is performed such that the strobe signal is transmitted once to perform the preheating, and the printing is performed next. However, when the preheating or the printing is performed, the strobe is performed. A description will be given of how the signal is divided into four, for example, and transmitted to perform preheating and printing. Figure 6
Is a logic circuit diagram of such a thermal head 2.
A predetermined electronic circuit (integrator 25, logic gate 26, heating resistor 27) is formed on a substrate (not shown). In addition, the board has a thermistor 3 and a connector 2 for detecting temperature.
1, 22 are provided.

The connectors 21 and 22 are terminals to which various signals are input. For example, from the connector 21, the shift register 23 receives the clock signal SG1, the latch register 24 receives the latch signal SG2, and the first electronic circuit (integrator 25, logic gate 26, heating resistor 27) receives the strobe signal SG4. However, the strobe signal SG5 is input to each of the second electronic circuits. Further, for example, the strobe signal SG6 is sent from the connector 22 to the third electronic circuit (the integrator, the logic gate, and the heating resistor similar to the above) and the fourth strobe signal SG6.
The strobe signal SG7 is input to the electronic circuit.

That is, depending on the clock signal, for example, 1
It sends a signal with a second interval, and based on its clock signal,
One line of print data (unprinted data in case of preheating) is transferred to the shift register. Next, when the latch signal is transmitted, print data (unprinted data in the case of preheating) is temporarily held in the latch register from the shift register. When the strobe signal is transferred, the corresponding heating resistor 27 is heated for the time corresponding to the pulse width of the strobe signal to preheat.

FIG. 7 is a time chart showing how printing is performed by alternately repeating preheating and printing with a strobe signal obtained by dividing the thermal head into four. In FIG. 7, as in the first embodiment, L11 indicates printing for one line, (1) is a clock, (2) is data, (3) is a latch, and (4) -1 is a first. Strobe, (4) -2 is the second strobe, (4) -3 is the third strobe,
(4) -4 is the fourth strobe, C11-1 is the preheat amount,
C11-2 is a heating amount required for printing. Preheated C1
In 1-1, T11 indicates the latch time, T12 indicates the preheat time, and at C11-2 for the heating amount required for printing, T13 indicates the latch time and T12 indicates the preheat time. In C11-2 of the heating amount,
T13 is the latch time, and T14 is the print time.

First, in order to perform preheating as C11-1 of the first cycle L11, for example, "L
(ON) ”is sent to prepare for data printing. In this case, since the data to be printed is not set, if the pulse width of the preheating time is set and transferred to the strobe signal, printing is not actually performed and the heating resistor does not heat the thermal paper. Preheat to. Next, the first cycle L
As C11-2 of 11, the print data for printing is fetched from the print data storage means 7 and set as in the first embodiment to prepare for data printing. In this case, each strobe signal is set to a pulse width during which printing can be performed and is transmitted sequentially. Thus, for example, the preheating (C11-1) as the first cycle L11 and heating (C11-2) required for printing, the preheating (C12-1) as the second cycle, heating required for printing, ... If the thermal strobe signals are alternately and repeatedly performed from the divided strobe signals, the non-printed portion of the thermal head 2 is always heated to a printable temperature before the actual printing, and suddenly print data is set in which head. In this case, printing can be performed quickly without lowering the printing speed, and power consumption can be saved.

Next, a third embodiment of the print control method for the thermal transfer printer according to the present invention will be described. In the third embodiment, an example in which a printer driver IC is used for print control of the printer will be described. In the first embodiment, the strobe signal for preheating and the strobe signal for printing are alternately transferred, but the printer driver I
By using C, a preheat instruction is given to a portion of the print data represented by bits that is not in the print state. That is, the print data of the strobe signal SG1 is
For example, in the case of "100011101110", the reverse data of this print data is "011100".
010001 ”and the print data is“ 1001111 ”.
In the case of "01101", "011000010010"
To get. In this way, since the print data "0" (print on) is the part where the print data exists, preheating is not performed, and the print data "1" (print off) part has the print data. Do not preheat because not.

At this time, the pulse width set in the strobe signal for printing is obtained by subtracting the preheating pulse width from the pulse width required for printing which is calculated and determined in advance. Further, in the present embodiment, even in high-speed printing by the printer driver IC instead of the strobe signal, the print data is heated to a temperature at which the thermal paper is heat-sensitive and printed, and the reversal data of the print data is at a temperature at which the thermal paper is not heat-sensitive. By alternately performing preheating for heating, the head of the non-printed portion is constantly placed in the print standby state. That is, the position of “0” of the print data “100011101110” is heated to a printable temperature, and the reverse data “01” of the print data is changed.
The position "0" of "1100010001" is heated to such a degree that the heat-sensitive paper is not heat-sensitive, and heating up to a printable temperature and heating to a temperature such that the heat-sensitive paper is not heat-sensitive are alternately repeated. As a result, even if the print data suddenly occurs in any of the heads, it does not take a heating time to heat to a temperature at which printing can be performed, and printing can be performed even at high speed printing without decreasing the printing speed.

In the above-described embodiment, the thermal head is preheated to a degree not sufficient for printing, and then printing is performed.
Although the preheating and the printing are performed alternately, the preheating may be performed after the printing, and the order of the printing and the preheating is not particularly limited. In addition, in the second embodiment,
Although the strobe signal is described as being divided into four and transmitted, it may be divided into three or five and the number of divisions of the strobe signal is not particularly limited.

[0030]

According to the first to third aspects of the present invention, the temperature of each head is detected by the thermistor provided in the thermal head of the thermal transfer printer, and the heating time required for heating is detected based on the temperature. (Strobe signal of a predetermined pulse width) is read from a pre-stored temperature conversion table, and preheating for heating a difference from a temperature below printing for a predetermined time and printing for heating a difference between a temperature up to printing for a predetermined time. By repeating the printing alternately, the head can maintain a predetermined temperature below printing and perform printing at a constant speed, and at the same time, it is possible to solve the problem that the printing is faint or partially dark.

According to the inventions of claims 2 to 4, the thermal head of the thermal transfer printer is divided into a plurality of control units, and strobe signals are transmitted to the respective control units.
Furthermore, by repeating preheating and printing alternately, the head can maintain a predetermined temperature below printing and perform printing at a constant speed, and at the same time, multiple heating resistors provided in the head are energized at one time. Therefore, there is an advantage that power consumption can be saved.

Further, the printer driver IC reverses the print-on and print-off of individual data of the print data so that when the print is off, the preheat-on data is obtained.
By alternately heating these, the head always maintains a predetermined temperature which is lower than printing, and printing can be performed at high speed without slowing the printing speed.

[Brief description of drawings]

FIG. 1 is a block configuration diagram for realizing a print control method for a thermal transfer printer according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing how a temperature based on an analog voltage value is converted into a digital value in a print control method for a thermal transfer printer according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram of a graph showing the relationship between the head temperature and the strobe width in the print control method for the thermal transfer printer according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram of a temperature conversion table 7 showing a strobe width with respect to a digital value in the print control method for the thermal transfer printer according to the embodiment of the present invention.

FIG. 5 is a time chart showing a print control method by the printer control means of the thermal transfer printer according to the embodiment of the present invention.

FIG. 6 is a logic circuit diagram of a thermal transfer printer thermal head according to a second embodiment of the invention.

FIG. 7 is a time chart showing a printing control method by the printer control means of the thermal transfer printer according to the second embodiment of the present invention.

[Explanation of symbols]

1 Printer control means 2 thermal head 3 Temperature detection means (thermistor) 4 Temperature acquisition means 5 Heating time acquisition means 6 Temperature conversion table 7 Print data storage means 8 Printing means (preheating means) 9 Microprocessor (CPU) 9a ROM 9b RAM

Claims (4)

[Claims] 1. A thermal head having a plurality of heating elements, which prints on a paper or the like by heating the heating elements to a predetermined temperature or higher, and print data is stored to the heating element based on the printing data. Control means for performing heating control on each heating element for each control unit with a plurality of heating elements as one control unit, temperature detecting means for detecting the temperature of the thermal head, and detection by the temperature detecting means Based on the temperature, it has a heating time acquisition unit that converts the amount of preheat required to heat the heating element to a temperature that does not reach printing and converts it into heating time, etc. A heating device for preheating all of the heating elements that did not generate heat based on the heating time acquired by the heating time acquisition means. 2. The printer according to claim 1, wherein the preheating is performed on each heating element for each control unit. 3. A thermal head having a plurality of heating elements, which prints on a paper or the like by heating the heating elements to a predetermined temperature or higher, and print data stored in the thermal head based on the printing data. Control means for performing heating control on each heating element for each control unit with a plurality of heating elements as one control unit, temperature detecting means for detecting the temperature of the thermal head, and detection by the temperature detecting means In a printer having a heating time acquisition means for converting the amount of preheat required to heat the heating element to a temperature at which printing is not possible based on the temperature and acquiring it, after printing by the heating element The heating for preheating is performed on all the heating elements that did not generate heat for printing based on the heating time acquired by the heating time acquisition means. Preheat control method of the printer. 4. The preheating control method for a printer according to claim 3, wherein the preheating is performed for each heating element for each control unit.