JPS60107370A - thermal printer - Google Patents

Abstract

PURPOSE:To provide a thermal printer which enables clear printing a character at the starting part of the printing by feeding a heat generating element with a power larger than the specified value for the specified number of initial characters in one line when a printing is performed with a thermal printer adapted to print one line at a time. CONSTITUTION:In a thermal printer so designed that a drive controller 14 makes heat generating elements generate heat selectively based on a pattern data to perform a printing moving a thermal head 6 along printing lines, a controller 11 during the printing operation sets the printing energization time for the heat generating elments at the initial value (about 2m/sec) for rhe specified number of characters from the print starting position to 20th characters, for instance, in each printing line to increase the supply power and shifts it to the normal value (about 1.7m/sec) following the 21st character.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a) transfer type or heat sensitive type thermal printer.

Prior Art Conventional thermal printers move a thermal head to a print line based on print data for one print digit input from an external device, and also move a large number of heating elements in the thermal head that is pressed against the recording paper. After selectively generating heat and printing characters for one print digit on the recording paper, the thermal head is released from the recording paper and the recording paper is fed by one printing line width, thereby causing the thermal head to perform a new operation. The next print line was being printed.

However, since the temperature of the thermal head decreases during the above-mentioned changeover operation, it is difficult to raise the temperature of the thermal head to a sufficient temperature at the start of printing, and there is a problem that the printed characters at the start of printing become unclear. Ta.

OBJECTS OF THE INVENTION In view of the above-mentioned conventional drawbacks, an object of the present invention is to provide a thermal printer that has a simple configuration and can clearly print characters even at the beginning of printing.

Example Hereinafter, embodiments will be described according to the drawings.

In Fig. 1, a frame 1 of a thermal printer is equipped with a platen 2, and the platen 2 is rotated by a paper feeding step motor (not shown) connected to the thermal printer. It supports the paper 3. A guide shaft 4 parallel to the platen 2 is attached to the frame l, and a carriage 5 is supported on this guide shaft 4 so as to be able to reciprocate.
A drive wire (none of which is shown) that is partially wound around the rotating shaft of the carriage step motor is attached (=1), and the carriage 5 is reciprocated as the carriage step motor rotates. A thermal head 6 is attached to the carriage 5 (n11).

The thermal head 6 selectively causes a large number of heating elements (not shown) arranged in the column direction of the thermal paper 3 to generate heat. As a result, characters are printed in the form of dots on the thermal paper 3 by coloring the thermosensitive coloring layer in accordance with the heat generating elements that generate heat.

In FIG. 2, when character data for printability is input from an external device (not shown) via an interface 1o, a control device 11 temporarily stores the input character data in a rewritable temporary memory 12. Write. and control device 1
1 accesses pattern data from the memory 13 based on the character data accessed from the temporary memory 12 and outputs it to the drive+N control device 14. In this memory 13, pattern data of each character corresponding to the I character data is written in advance. The drive control device 14 (n11) rotates the carriage step motor to press the thermal head 6 onto the thermal paper 3 while moving the carriage 5 along the print line. Further, as the carriage 5 moves, the drive control device 14 selectively causes the heating elements to generate heat based on the pattern data.

As a result, characters are printed on the thermal paper 3 in the form of dots by coloring the thermosensitive coloring layer corresponding to the heating element to which the printing current is supplied. During this printing operation, the control device 11 sets the printing current energization time to the heating element to an initial value (approximately 2IisCC) and supplies power from the printing start position to a predetermined number of characters, for example 20 characters, in each printing line. On the other hand, the difference ('1.7 m5e) between the initial m (2 m5ec) and the correction value [approx.
c) to reduce the power supply.

Through the above operation, the control device 11 prints one print digit of characters based on the character data, and then writes the character data of the next print line input from the external device into the temporary memory 12. In addition, the control device M11 releases the thermal head 6 from the thermal paper 3, and after feeding the thermal paper 3 by one printing digit by the rotational drive of the paper feeding step motor, the controller M11 moves the thermal head 6 from the printing end position in the opposite direction as in the above operation. Operate bidirectional printing.

Next, the operation of switching the energization time of the printing current applied to the heating element will be explained with reference to FIGS. 3 and 4.

First, in block 20, the control device 11 sets the correction values for the energization time for the character counter for counting printed characters and the heating element to 0°'. Then, the control device 11 applies a printing current to the heating element in block 21, and then sets the energization time of the printing current to the heating element to the difference between the initial Jtll and the correction (m) in block 22. Next, the control device 11 In block 23, it is determined whether or not the time for applying the printing current to the heating element has elapsed.If this l'll determination is NO, the process moves to block 23.

On the other hand, if this determination is YES, the control device 11 finishes applying the printing current to the heating element in block 24, and then applies the application cycle (5, 6 m5ec) set in advance in block 25 and the application cycle (5,6 m5ec) set in block 22 as described above. Set the pause time based on the difference from the energization time. Next, the control device 11 adds 11 to the block 26 to determine whether the pause time has elapsed, and if this determination is NO, the control device 11 adds 11 to the block 26.
Move to. -Force If this determination is YES, the control device 11 determines whether one character has been printed in block 27, and if the result is +11 constant or NO, the control device 11 moves to block 21. On the other hand, if this determination is YES, the control device 11 increments the character counter in block 28 and then
At block 29, it is determined whether the count candy of the character counter has reached a predetermined number of characters [20]. If this determination is YES, the control device 11 sets correction #j (0.3 msec) in block 30, and then determines +a in block 31 whether the printing operation for one print line has been completed. On the other hand, if the determination at block 29 is NO, the control device @11 moves to block 31. If the determination of rI in block 31 is NO, the process moves to #I block 21. On the other hand, if this determination is YES, the control device 11 finishes the printing operation for one printing digit and moves on to the printing operation for the blown printing line.

Therefore, in this embodiment, when printing a predetermined number of characters from the printing start position, the printing current supply time to the heating element is set to the initial J[II value (2m5ec), while when printing subsequent characters. To make the characters clearer, the printing current energization time to the heating element is set to the difference between the initial value and the correction value (1.7m5ec), and the power supplied to the photothermal element at the start of printing is made larger than the predetermined amount. Can be printed.

In addition, although this practical example has a structure in which the energization time of the printing current to the heating element is changed according to the number of characters to be printed, the present invention has a configuration in which the energization time of the printing current to the heating element is changed according to the number of dots on the heating element to which the printing current is applied, as shown in FIG. It is also possible to implement a configuration in which the energization time is changed over. In FIG. 5, the same operations as those in this embodiment are given the figure numbers shown in FIG. 3, and detailed explanation thereof will be omitted.

That is, in block 40, the control device sets a dot counter for counting the number of heating elements to which the printing current is applied and a correction value to "o", and then proceeds to block 21.

Then, the process moves to block 26 according to the operation shown in FIG.
If the determination is YES, the control device counts up the dot counter in accordance with the number of heating elements to which the printing current is applied in block 41, and then counts up the dot counter in block 42 to a predetermined number of dots (for example, 300 f-IJ determines whether or not the dot has been reached. If this determination is YES, the control device sets the correction (L(j (0, 3m5ec) in block 43, then determines whether one character has been printed or not in block 44, and
If this determination is NO, the process moves to block 21. On the other hand, n
If the t+ block 42 is NO, the controller moves to block 44. And the determination of block 44 is YES.
In this case, the control device determines in block 45 whether or not characters for one print digit have been printed, and if the determination is NO, the control device moves to block 21 described above. On the other hand, if the determination in block 45 is YF or S, the control device ends the printing operation and moves on to the printing operation for the next printing line.

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention provides a thermal printer that supplies power to a PfilN heating element of a thermal head based on data input from an external device to print on a recording sheet line by line. The first line of data? With a simple configuration that controls the power supplied to the niJ heat generating element to be more than a predetermined amount for characters with the i constant, and to supply a predetermined amount of power for subsequent characters, even the characters at the start of printing can be clearly seen. This is a thermal printer that can print on.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing the outline of a thermal printer, Figure 2 is an electronic block diagram of the thermal printer, Figure 3 is a brooch showing the switching operation of the energization time, and Figure 4 is the energization time of the printing current to the heating element. FIG. 5 is a flowchart showing a modified embodiment. In the figure, 3 is thermal paper used as recording paper, and 6 is a thermal head. Patent applicant Brother Industries, Ltd. Agent Patent attorney Ken Ito −

Claims (1)

[Claims] 1. In a thermal printer that supplies power to required heating elements of a thermal head based on data input from an external device and prints on a recording sheet line by line, A thermal printer characterized in that the power supplied to the heating element is set to be greater than a predetermined amount for the first predetermined number of characters among the data, and the predetermined power is supplied for subsequent characters.