JPH03118165A - Printing control method for thermal printer - Google Patents

Abstract

PURPOSE:To control the printing density to be uniform by a method wherein a receiving period of time for a print data which is fed to a thermal head is measured, and a pulse width for printing pulse is corrected by a correction data which corresponds with the measured period of time and is applied to the thermal head to perform printing. CONSTITUTION:In a memory 11m, a time table Tp which is composed of time date n1-ni which is compared with a receiving period of time of dot data DA for one line and correction date l1-li which correspond with these time data n1-ni has been stored. A receiving period of time for the dot data DA which are fed from an external computer, etc., is measured by a control unit 11a, and this measured receiving period of time and the time data n1-ni on the time table Tp are compared, and a time data n1-ni is selected by this comparison, and a correction date l1-li which corresponds with this time data n1-ni is set. By the set correction data l1-li, a pulse width of a printing pulse P is corrected to a width by which a power connection time to give a designated temperature to a thermal bead 6 is obtained, and the pulse width is applied to a bead driving circuit 15.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a printing control method for a thermal printer that prints barcodes, characters, graphics, etc.

``Prior Art J'' A thermal printer TP shown in FIG. 5 is known as a conventional thermal printer of this type.

In this figure, 1 is a transfer ribbon, the upper surface of which is coated with heat-melting ink. This transfer ribbon 1
is sent out from the supply roller 2, passes through the printing section 3, and is taken up by the take-up roller 4.

Reference numeral 5 denotes a transfer paper, which is superimposed on the ink-applied surface of the transfer ribbon l and passes through the printing section 3 together with the transfer ribbon l. The printing section 3 includes a thermal head 6 and a platen roller 7. The thermal head 6 is divided into four parts, each of which is provided with a heat generating cell (not shown) that generates heat when energized. During printing, the thermal head 6 is urged toward the platen roller 7, presses the transfer ribbon 1 and the transfer paper 5, and the heat generating cell generates heat, discharging the ink applied to the transfer ribbon. It is melted and transferred onto the transfer paper 5. At this time, the platen roller 7 rotates by a minimum angle in the direction of the arrow Y, and moves the transfer ribbon 1 and the transfer paper 5 in translation in one-dot increments. Further, a thermistor 8 is attached to the thermal head 6, and the temperature of the thermal head 6 is measured by this thermistor 8.

Next, the electrical configuration of the above-mentioned thermal printer TP will be explained with reference to FIG. 6.

In FIG. 6, 10 is a temperature detection circuit which converts the output of the thermistor 8 into temperature data TD (digital data) and then supplies it to the control section 11.

Control part l! is the CPU (central processing unit), work memory,
It consists of a program memory, etc., and controls each part of the thermal transfer printer TP, and outputs printing pulses P. The pulse width of this printing pulse P is adapted to change based on temperature data TD supplied from the temperature detection circuit 10. That is, when the temperature of the thermal head 6 is low, the control section 11 widens the width of the printing pulse P, but when the temperature of the thermal head 6 rises, the control section 11 narrows the pulse width as the temperature rises. Further, when the temperature of the thermal head 6 abnormally rises and exceeds a predetermined limit temperature, the control section 11 increases the time during which the printing pulse P is turned off.

Reference numeral 12 denotes a motor drive circuit, which drives the step motor 13 under the control of the control section 11 to rotate the platen roller 7 by a minute angle. In addition, 14 is a print data memory, which is used to input data from an external computer, etc. to the interface circuit 2.
0 and dot data D supplied via the control unit 11
Record A (print data). The recorded dot data DA is read out by the address signal ADH supplied from the control section 11 and supplied to the head drive circuit 15. The head drive circuit 15 causes the thermal head 6 to generate heat based on the dot data DA supplied from the print data memory I4, and causes the thermal head 6 to generate heat.
The dot data DA is stored in these registers, and the print pulse P is transmitted from the control unit II to the registers and gate circuits having the same number of bits as the heating cells.
When the dot data DA is supplied, a specific heat generating cell of the thermal head 6 is energized to generate heat based on the stored dot data DA. In this case, the energization time of the heating cell and the pulse width of the printing pulse P are equal.

Next, the print control method of this thermal printer TP will be explained in the seventh section.
This will be explained with reference to the flowchart shown in the figure.

First, in step Sl, the thermal printer TP is brought into an online state.

Next, in step S2, the lth line dot data DAI supplied from an external computer or the like as shown in FIG. 8(A) is received, and it is determined whether this reception is complete. If the dot data DAI is being received, the determination result is "NO" and data reception continues.

On the other hand, when the reception of the dot data DAI is completed, the determination result becomes rYESJ, and the process proceeds to step S3. Further, the dot data DAI received in step S2 is transmitted to the interface circuit 20 and the control unit 11.
The print data is stored in the print data memory 14 via the print data memory 14. Further, when the dot data DAI is supplied, the thermal head 6 is urged toward the platen roller 7 in response to a command from the control section 11, thereby bringing the transfer ribbon 1 and the transfer paper 5 into pressure contact.

Next, in step S3, the address signal ADH is supplied from the control section 2 to the print data memory 14, and as shown in FIG.
At time TI shown in b), the dot data DA in the print data memory 14 is sequentially transferred to the head drive circuit 15 and stored in the register of the head drive circuit 15.

Next, in step S4, the pulse width of the print pulse P is determined based on the temperature data TD supplied from the temperature detection circuit IO to the control unit 11, and thereby, the pulse width of the print pulse P is determined as shown in FIG.
The energization time TDA 1 of the thermal head 6 shown in b) is set.

Next, in step S5, when the printing pulse P is applied from the control unit 11 to the head drive circuit 15, energization of the thermal head 6 is started, whereby the heat generating cells of the thermal head 6 generate heat, and the transfer ribbon 1 The ink is melted and printing is performed on the transfer paper 5. Further, when the thermal head 6 starts to be energized, in step S6,
The reception of the second line of dot data DA2 shown in FIG. 8(a) is started.

Next, in step S7, it is determined whether the energization of the thermal head 6 that started in step S5 has been completed. If the current is being energized, the judgment result will be "NO", the energization will continue, and once the energization is completed, the judgment result will be rYE.
sJ, and the process proceeds to step S8.

Next, in step S8, the pulse PM shown in FIG. The transfer ribbon 1 and the transfer paper 5 move in parallel for a length corresponding to one dot. Next, after the step motor 13 is driven in step S9,
When the initial vibration of the drive is attenuated and stopped, step S2
Returning to step 62 to step S9, as described above,
The operation is repeated.

``Problem to be Solved by the Invention'' By the way, in the above-described printing control method for a thermal printer, the reception of one line of dot data DA is completed, and this received data DA is transferred to the head drive circuit.
5, and printing is not performed until the print pulse P is further applied from the control section 11 to the head drive circuit 15. For this reason, if the transmission speed of the dot data DA sent from an external computer etc. becomes slow and the time to receive the data becomes long, for example, the dot data DA2 on the second line shown in FIG. When the reception time T2 becomes longer as time T3 shown in FIG. 9(A), printing is performed during the energization time TDAI of the first line of the thermal head 6, as shown in FIG. 9(B). The time Twl from the second line until printing is performed at the energization time TDA2 becomes longer than the time TV shown in FIG. 8 (b), and the thermal head 6 cools down in accordance with this longer time Become. When the thermal head 6 cools down and its temperature becomes low in this manner, the control section 11 supplies the head drive circuit I5 with a print pulse P having a pulse width determined based on the low temperature data TD.

According to such control, the thermal head 6 reaches a predetermined temperature when the third line is printed, so that the printing density becomes constant. However, in reality, the control unit 1
Since the temperature data TD supplied to 1 is the data obtained by detecting the temperature of the thermal head 6 by the thermistor 8 in a short time,
The data is not necessarily correct and often deviates from the actual temperature. Therefore, even if the print density is controlled to be constant as described above, if the thermal head 6 becomes colder than necessary, printing may be interrupted. The density may be reduced, which causes a problem of poor print quality.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a print control method for a thermal printer that can perform high-quality printing by controlling the print density to be constant.

"Means for Solving the Problem" The present invention measures the reception time of print data supplied to a thermal printer from an external device in a control unit, and uses correction data corresponding to this measured time to generate pulses of print pulses. The feature is that printing is performed by correcting the width and applying it to the thermal head.

"Function" According to the present invention, when the transmission speed of print data supplied to the thermal printer from an external device is fast or slow, the control unit measures the reception time of the print data, and this measured time The pulse width of the print pulse is corrected using correction data corresponding to the correction data. and,
The corrected printing pulse is applied to the thermal head to perform printing. Therefore, the transmission speed of print data supplied from an external device is slow and the reception time is long, and even if the thermal head becomes colder than necessary in response to this longer time, the thermal head is kept at the specified temperature and printing is performed. Since this can be done, the printing density can be kept constant.

"Embodiment" Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the electrical configuration of a thermal printer according to an embodiment of the present invention.
Components corresponding to those in the figure are given the same reference numerals.

Further, the mechanical configuration of the thermal printer is similar to the configuration shown in FIG.

The thermal printer of this invention differs from the one shown in FIG. 6 in that the control for setting the pulse width of the printing pulse P in the control section 11a is changed.

That is, the control unit 11a is provided with a memory I1m, and this memory I1m stores time data r++-ni to be compared with the reception time of the dot data DA for line 2, and correction data 1. A time table Tp (shown in the figure) consisting of .about.1i is stored.

Then, the control unit 11a measures the reception time of the dot data DA supplied from an external computer, etc., and compares this measured reception time with the time data nI-ni of the time table Tp. Time data n + ""' n 1 is selected by comparison, and correction data 11 to Ii corresponding to this time data n1 to ni are
is set. And the set correction data! ,
11, the pulse width of the print pulse P is corrected to a width that provides a current-carrying time during which the thermal head 6 reaches a predetermined temperature, and is applied to the head drive circuit 15.

Hereinafter, a printing control method for a thermal printer having a control section 11a that performs such control will be described with reference to a flowchart shown in FIG.

First, in step Sat, the thermal printer is placed on-line.

Next, in step Sa2, the l-th line dot data Dal supplied from an external computer or the like as shown in FIG. ,
Further, when the radar code GSI of the dot data Dal is detected, measurement of the reception time of the data Dal is started. Furthermore, when the dot data Dal is supplied, the thermal head 6 is urged toward the platen roller 7 in response to a command from the control section 11a, thereby bringing the transfer ribbon I and the transfer paper 5 into pressure contact.

Next, in step Sa3, it is determined whether the reception of the dot data Dal is complete. If the dot data Dal is being received, the judgment result is rNO.
J, and the reception of data Dal continues. On the other hand, when the reception of the dot data Dal is completed, the determination result becomes rYEsJ, and the process proceeds to step Sa4.

Next, in step Sa4, the address signal ADH is supplied from the control section 11a to the print data memory 14, and the dot data Dal in the print data memory 14 is sequentially transferred to the head drive circuit 15 and stored in the register of the head drive circuit I5. be done.

Next, in step Sa5, the header code GS2 of the second line is detected by the control unit 11a after the processing time Tal of the external computer shown in FIG. The reception time TR is measured.

Next, in step 5a5-1, the reception time TR obtained in step Sa5 and the memory I of the control unit lIa are
Time 11...n of time table Tp stored in 1m
i is compared with the corrected data 11...
Ii is required.

Next, in step Sa6, the correction data obtained in step 5a5-1 is set.

Next, in step Sa7, the temperature of the thermal head 6 is detected by the thermistor 8, the detected analog data is supplied to the temperature detection circuit 10, and the analog data is further converted into digital data by the temperature detection circuit 10. The temperature data TD is then supplied to the control section 11a.

Then, the pulse width of the printing pulse P is set based on the temperature data TD.

Next, in step 5a7-1, the pulse width of the printing pulse P set in step Sa7 is changed to step Sa6.
This is corrected using the correction data set in , and thereby the energization time T Dal of the thermal head 6 shown in FIG. 4 (b) is set.

Note that at time Ta2 shown in FIG. 4(a), the dot data Dal in the print data memory 14 is
It also shows the time until the printing pulse P is stored in the register and has a pulse width corresponding to the energization time TDal ((b) of the same figure).

Next, in step Sa8, a printing pulse P is applied from the control section 11a to the head drive circuit 15, and the thermal head 6 is energized. As a result, the heating cell of the thermal head 6 generates heat, the ink on the transfer ribbon 1 is melted, and printing is performed on the transfer paper 5.

Next, in step Sa9, 2
The reception of the dot data Da2 for the line is started. Next, in step 5alO, it is determined whether the energization started in step Sa8 has been completed. If the current is being energized, the judgment result will be rN OJ, the energization will continue, and when the energization is completed, the judgment result will be rY E S
J, and the process proceeds to step 5a11.

Next, in step Sa[L, the pulse PM shown in FIG. The transfer ribbon I and the transfer paper 5 move in parallel for a length corresponding to one dot.

Next, in step 5a12, the step motor 13
After being driven, when the initial vibration of the drive attenuates and stops, the processing of the l-th line ends.

Next, the processing from the second line onwards will be explained with reference to the flowchart shown in FIG.

First, in step sbt, 2
It is determined whether the reception of the dot data Da2 for the line is completed. If the dot data Da2 is being received, the judgment result is "NOJ" and the data Da2 is being received.
2 continues to be received.

On the other hand, when the reception of the dot data Da2 is completed, the determination result becomes rYESJ and the process proceeds to step Sb2.

Next, in step Sb2, the dot data Da2 in the print data memory I4 is sequentially stored in the register of the head drive circuit 15 during the time Ta3 shown in FIG. 4(A).

Next, in step Sb3, the pulse width of the print pulse P is set based on the temperature data TD supplied from the temperature detection circuit IO to the control unit 11a, and furthermore, the pulse width of the print pulse P is set by one line. It is corrected by the correction data obtained from the reception time of the eye dot data Dal, and thereby the energization time TDa2 of the thermal heptome 6 shown in FIG. 4(b) is set.

Next, in step Sb4, a printing pulse P is applied from the control section 11a to the head drive circuit 15 to start energizing the thermal head 6, thereby printing on the transfer paper 5.

Next, in step Sb5, 3
Reception of the dot data Da3 for the line is started.

Next, in step Sb6, it is determined whether energization of the thermal head 6 in the second line is completed. If the current is being energized, the determination result is "NO" and the energization is continued, and if the energization is completed, the determination result is rYESJ and the process proceeds to step Sb7.

Next, in step Sb7, the pulse PM shown in FIG. 4(c) is applied from the control unit 11a to the motor drive circuit 12, thereby driving the step motor 13.
The platen roller 7 rotates by a small angle, and the transfer ribbon 1 and the transfer paper 5 move in translation by a length corresponding to one dot.

Next, in step Sb8, the step motor 13 is driven, and when the initial vibration of the drive is attenuated and stopped, the process of the second line is completed and the process returns to step Sb+. Then, the operations from step Sbl to step Sb8 described above are repeated, and the third and subsequent lines are printed in the same manner as the second line.

F Effects of the Invention J As explained above, according to the present invention, the control section measures the reception time of print data (dot data) supplied to the thermal printer from an external device, and the time corresponding to this measured time is measured. Since the pulse width of the print pulse is corrected using the correction data and applied to the thermal head to perform printing, the transmission speed of the print data sent from an external computer etc. becomes slow and the print data is delayed. Even if the receiving time becomes longer and the thermal head cools down by that time, the thermal head is energized by the print pulse that has been corrected as described above, so printing can be performed with the thermal head at a predetermined temperature. I can do it. This makes it possible to keep the print density constant, which has the effect of making it possible to print with good quality.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the electrical configuration of a thermal printer according to an embodiment of the present invention, and FIG. 2 is a diagram showing a printing control method for the thermal printer, in which dot data DA ( print data)
FIG. 3 is a flowchart showing the process for correcting the energization time of the thermal head. In the print control method of the same thermal printer, the dot data DA (print data) of the second and subsequent lines supplied from an external computer etc. ) is a flowchart diagram showing the processing of FIG.
A), (B), and (C) are diagrams showing the timing of dot data DA, thermal head energization time, and step motor drive pulse of the thermal printer shown in FIG. 1, and FIG. 6 is a diagram showing the electrical configuration of a conventional thermal printer TP, and FIG. 7 is a diagram showing a conventional thermal printer TP.
Flowchart diagram showing the printing control method, Fig. 8 (a)
, (B) and (C) are diagrams showing the timing of dot data DA, thermal head energization time, and step motor drive pulse of the conventional thermal printer TP, and FIG. Line dot data D
FIG. 6 is a diagram showing the timing of the dot data DA and the energization time of the thermal head when the reception time T2 of A2 becomes longer. DA...Dot data (print data), l
, ~11...Correction data, ADH...
Address signal, P...print pulse, TD...
...Temperature data, 6...Thermal head, 7
...Platen roller, 8...Thermistor, 10...Temperature detection circuit, lla...
・Control unit, 1m...Memory, 2...Motor drive circuit, 3...Step motor,...Print data memory, 5...Herad Drive circuit, 0... Ink face circuit.

Claims (1)

[Claims] A control unit measures a reception time of print data supplied to the thermal printer from an external device, corrects the pulse width of a print pulse using correction data corresponding to the measured time, and applies the pulse width to the thermal head. A printing control method for a thermal printer characterized by printing.