JPH08224902A - Line thermal printer and printing method thereof - Google Patents

Abstract

PURPOSE: To obtain a line thermal head capable of preventing printing irregularity by preliminarily supplying a current to a thermal head to a degree not excessively cooling the thermal head up to a next printing time with respect to dots developed in color continuously. CONSTITUTION: A command is issued to a thermal head 1 from a thermal head heating element control part 5. At this time, the next printing line data inputted to a next printing line data memory part 3 from a printing line data forming part 2 is inputted to the thermal head heating element control part 5 and the thermal head heating element control part 5 takes the AND of a printing pattern printed this time and a printing pattern printed next to determine heating elements performing next printing in succession to the printing of this time. The thermal head heating control part 5 issues a command so as to allow a current to flow to the heating elements of the thermal head continuously up to next printing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line type thermal printer and a printing method therefor, and more particularly to printing by receiving current from a small power source such as a battery and generating heat for use in a portable terminal device or the like. The present invention relates to a line type thermal printer and a printing method thereof.

[0002]

2. Description of the Related Art FIG. 2 is a schematic view showing an example of a state of divided energization in a line type thermal printer. Line-type thermal printers, such as line-type thermal printers used in portable terminal devices, print by receiving current from a small-scale power source such as a battery and generating heat. Since there is a limit to the number of dots), if the number of dot lines for printing one dot line is large, it is divided into several groups, and so-called divided printing is performed in which electricity is supplied to each group. In this case, the total printing time (total energization time) of the dot line changes depending on the number of divisions of one dot line. Therefore, the time from the start of printing one dot line to the start of the next dot line (energization time interval) changes.

For example, a print pattern 2 as shown in FIG.
When printing 2, the number of black dots 23 to be printed in each dot line from the 1st dot line to the 11th dot line indicated by the dot line number 21 is "3" from the 1st dot line to the 3rd dot line. However, the fourth dot line and the fifth dot line are “16”. Therefore, if the number of dots that can be simultaneously energized is "3", the energization division number 24 of each dot line is "1" from the first dot line to the third dot line and from the sixth dot line to the eleventh dot line. However, the fourth dot line and the fifth dot line are “6”. Therefore, if the energization time for each dot for one division is 1 ms, the total energization time for each dot line to be printed is 1 ms for one dot line.
It takes 6 ms for 6 divided dot lines.

As described above, since the number of divisions of one dot line for printing changes, printing is performed with different total energizing time for each dot line, and therefore, the line type thermal head is used for each dot line. The cooling status changes. Therefore, if the energization time for the thermal head is calculated and controlled only from the temperature of the thermal head and the voltage value of the voltage supplied to the thermal head, the reached temperature of each dot at the time of printing will be different. Therefore, print unevenness occurs.

[0005]

As described above, the conventional line type thermal printer, which is supplied with a current from a small-scale power source, has a limit in the number of dots that can be energized at the same time. If the number of dots to be printed is large, one dot line must be divided into several groups and divided printing must be performed, so that the total energization time for one dot line changes. Therefore, there is a drawback that the energization time interval from the start of energization to one dot line to the start of energization to the next dot line changes, the cooling state of the thermal head changes, and printing unevenness occurs. ing.

An object of the present invention is to energize the thermal head so that the thermal head does not excessively cool until the next printing, for dots to be colored continuously in the next dot line printing. An object of the present invention is to provide a line type thermal printer that can prevent uneven printing.

[0007]

A line-type thermal printer of the present invention comprises a line-type thermal head composed of a plurality of heating elements capable of driving a predetermined number at the same time, a print line data creating section for generating a dot pattern to be printed, This time print line data storage section that stores the dot information to be heated this time, the next print line data storage section that stores the dot information to be printed next time, and the heat generation control of the dots to be printed this time Thermal that controls the heat generation of the corresponding dot until the next printing by taking the logical product of the heat generation dot information of the line data storage part and the heat generation dot information of the next printing line data storage, and controls the paper feed motor. And a head heating element control unit.

Further, in the printing method of the line type thermal printer of the present invention, a dot pattern to be printed by the line type thermal head composed of a plurality of heating elements capable of driving a predetermined number at the same time is generated, and the dot information for heating this time is stored. Store the dot information to be printed next time,
At the same time as controlling the heat generation of the dots to be printed this time, the logical product of the heat generation dot information of this time and the next heat generation dot information is taken, and the heat generation of the corresponding dots is controlled until the next printing,
In addition, the paper feed motor is controlled.

[0009]

Next, the present invention will be described with reference to the drawings. Referring to FIG. 1, which is a block diagram showing an embodiment of the present invention, a line-type thermal printer of this embodiment has a line-type thermal head 1 composed of a plurality of heating elements capable of simultaneously driving a predetermined number and a dot pattern to be printed. The print line data creation unit 2 to be generated and the current print line data storage unit 4 for storing the dot information to be generated this time
And the next print line data storage section 3 for storing the dot information to be printed next time, and the heat generation control of the dots to be printed this time, and at the same time, the heat generation dot information of the current print line data storage section 4 and the next print line data storage section. The thermal head heating element control unit 5 controls the continuation of heat generation of the corresponding dot until the next printing, and controls the paper feed motor 6 by taking a logical product with the heat generation dot information of 3.

In FIG. 1, a line type thermal head (thermal head) 1 has a plurality of heating elements capable of simultaneously heating a designated number of heating elements. The print line data creation unit 2 creates a print pattern for each print dot line. This time, the print line data storage unit 4 is created by the print dot line data creation unit 2,
The print line data to be printed this time is stored. The next print line data storage unit 3 stores the print line data to be printed next time, which is created by the print dot line data creation unit 2. The thermal head heating element control unit 5 inputs the print dot line stored in the print line data storage unit 4 this time, counts the number of print dots in the print pattern, and prints one dot line from the number of dots that can be printed at the same time. Calculate the number of divisions. In addition, the thermal head heating element control unit 5 uses the next print line data storage unit 3
Input the print dot line stored in, calculate the logical product of the print pattern and the print pattern to be printed this time for each heating element, and calculate whether to print this time and the next time. The paper feed motor 6 drives the dot line feeding operation of the printing paper by the drive signal from the thermal head heating element control unit 5.

The dot line feeding operation of the printing paper is inversely proportional to the number of divisions of each dot line, and becomes faster when the number of divisions is small and slower when the number of divisions is large. The one-divided energization time for each print dot line of the thermal head 1 is determined by the head temperature and the input voltage, and the total energization time for one dot line increases as the number of divisions increases. Then, the time from the end of energization of one dot line to the energization of the next dot line changes, and the cooling state of the head changes. That is, when the number of divided dot lines this time is small, the interval time until the energization of the next dot line is started is short, and the cooling of the head is small. On the contrary, when the number of divisions of this dot line is large, the interval time until the energization of the next dot line is started is long and the cooling of the head is large. From this, the cooling time until the energization of the next dot line is started increases / decreases in proportion to the number of divisions of the print dot line this time, so that the print density changes. In order to prevent this, if there is a dot that continuously develops color from the end of printing this dot line to the start of printing of the next dot line, until the next energization of the dot energized this time, A small amount of current is continuously energized so that the total degree of energization time of the dot line this time is the same when the thermal head is cooled when the number of divisions is large and when it is small.

Next, the operation of the embodiment configured as described above will be described by taking the print pattern shown in FIG. 2 as an example. The thermal head 1 has a large number of minute heating elements arranged in a line so as to correspond to the width of the printing paper. For example, the width of the printing paper is 64 mm, and 8 heating elements per 1 mm are provided. If provided, a total of 512 heating elements are arranged in one row. At this time, the feeding pitch of the printing paper is, for example, 8 steps per 1 mm. (That is, the dot line pitch is 1/8 mm
Is. The energization time for the thermal head 1 is divided into a plurality of times for each dot line in accordance with the number of print dots on the dot line. At this time, which dot corresponds to which heating element is to be energized is created by the print line data creation unit 2 and input to the current print line data storage unit 4. The print pattern stored in the print line data storage unit 4 this time is input to the thermal head heating element control unit 5, and the thermal head heating element control unit 5 instructs the thermal head 1.
At this time, the next print line data input from the print line data creation unit 2 to the next print line data storage unit 3 is input to the thermal head heating element control unit 5, and the thermal head heating element control unit 5 prints the print pattern this time. And the print pattern to be printed next time are taken, and the heating element to be printed next time continuously after printing this time is determined. The thermal head heating element control unit 5 instructs the continuous heating of the heating elements of the thermal head 1 in the dots to be continuously printed until the next printing.

The energization division of the print pattern of FIG. 2 is "1" from the first dot line to the third dot line and from the sixth dot line to the eleventh dot line, and the fourth dot line and the fifth dot line. Is "6". Therefore, if the energization time for one division is 1 msec,
The printing of the fourth dot line is started 1 msec after the printing of the third dot line, but the printing of the fifth dot line is started 6 msec after the start of printing the fourth dot line. Thus, the print start time of a certain dot line changes depending on the division number of the dot line before that.

Conventionally, the number of divisions differs due to the different dot line print patterns, and the time from the start of printing the previous dot line to the start of printing the next dot line differs accordingly. And the printing time varies due to a difference in arrival time of the thermal head at the same energization time. In order to avoid this, for the dots to be colored continuously in the printing of the next dot line, the thermal head is energized to the extent that the thermal head does not excessively cool until the next printing. This is to prevent the occurrence of.

[0015]

As described above, according to the present invention,
The thermal head heating element control unit takes the logical product of the line data to be printed this time stored in the print line data storage unit this time and the line data to be printed next time stored in the print line data storage unit next time, and continuously By continuously supplying current to the dots that generate heat so that the cooling state of the head temperature is stable, when printing the next dot line, the head temperature is stable regardless of the division number of the previous dot line. The effect is to prevent the occurrence of print unevenness.

[Brief description of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of a divided energization state in a line type thermal printer.

[Explanation of symbols]

 1 line type thermal head (thermal head) 2 print line data creation section 3 next print line data storage section 4 current print line data storage section 5 thermal head heating element control section 6 paper feed motor

Claims (2)

[Claims] 1. A line-type thermal head comprising a plurality of heating elements capable of driving a predetermined number at the same time, a print line data creating section for generating a dot pattern for printing, and a current print line for storing dot information for the current heat generation. The data storage unit, the next print line data storage unit that stores the dot information to be printed next time, and the heat generation control of the dots to be printed this time, and at the same time, the heat dot information in the current print line data storage unit and the next print line. It is characterized by including a thermal head heating element control unit that takes a logical product with the heating dot information of the data storage unit, controls the heating continuation of the dot until the next printing, and controls the paper feed motor. Line type thermal printer. 2. A dot pattern to be printed is generated on a line type thermal head composed of a plurality of heating elements capable of driving a predetermined number at the same time, dot information to be heated this time is stored, and dot information to be printed next time is stored. Every
At the same time as controlling the heat generation of the dots to be printed this time, the logical product of the heat generation dot information of this time and the next heat generation dot information is taken, and the heat generation of the corresponding dots is controlled until the next printing,
A printing method for a line-type thermal printer, which is characterized by controlling a paper feed motor.