JPH07329339A - Line type thermal printer, and sheet-feed motor driving method therefor - Google Patents

Abstract

PURPOSE:To reduce the printing disorder and the noise by driving a dot line print finished sheet-feed motor after a predetermined time without immediately driving the motor during printing at present when there is a difference of a predetermined amount or more between the number of print dots of a dot line during the printing at present and the number of the print dots of next dot line. CONSTITUTION:A line type thermal head 1 has a plurality of heat generating elements to be simultaneously driven in the predetermined number. A printing pattern developing unit 3 stores the painting pattern of a plurality of dot lines. Further, a printing dot counter 4 counts the number of the printing dots at each dot line. A number-of-printing dots memory 5 stores the number of the printing dots. Further, a sheet-feed motor 6 drives a sheet, a print controller 2 stops the driving of the motor 6 for a predetermined time after the dot line printing during printing at this time is finished when there is a difference of a predetermined amount or more between the number of the dots of the dot line during printing at present and the number of the dots of the next dot line, and drives the motor 6 immediately thereafter.

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 more particularly to a line type thermal printer mounted on a portable terminal or the like.

[0002]

2. Description of the Related Art Conventionally, a thermal printer that supplies a current from a small power source such as a battery to a thermal head and develops or transfers color due to the heat generated is limited in the current that can be energized at one time. The current is applied to the thermal head by dividing it into several parts. In that case, the printing time of the dot line changes depending on the number of divisions, and the operating frequency of the paper feed motor changes.

For example, when printing a print pattern as shown in FIG. 3, assuming that the maximum number of dots that can be energized at one time is three, energization division from the first dot line to the eleventh dot line is performed. The number is 1, 1, 1,
6,6,1,1,1,1,1,1,1. The paper feed motor has a maximum operating frequency of 500 pps (cycle 2
msec), the energization time for one division is 1 msec.
In that case, the device operates at the maximum operating frequency up to two divisions.
When the number of divisions increases or decreases, the motor operating frequency (operating cycle) changes. In the example of FIG. 3, the motor operating frequency from the first dot line to the third dot line is 500 pps because the number of divisions is 1, whereas the number of divisions of the fourth dot line is 6, which is shown in FIG. As shown, the frequency drops to 167 pps. Also, when the fifth dot line is changed to the sixth dot line, since the division is changed from 6 divisions to 1 division, the motor operating frequency is 167pps to 500pps.
Go up to. The paper feed motor cannot follow the increase / decrease of the frequency, which may cause a phenomenon such as resonance or step out, which disturbs the printing and increases noise.

[0004]

In this conventional line type thermal printer, the printing time of the dot line changes depending on the number of divisions, and the operating frequency of the paper feed motor changes, so the operation of the paper feed motor changes in frequency. Cannot be followed, which may cause vibration other than the originally expected operation, which causes disturbance of printing and increase of noise.

[0005]

A line-type thermal printer of the present invention is a line-type thermal head comprising a plurality of heating elements capable of driving a predetermined number at the same time, and a print pattern developing section for storing print patterns of a plurality of dot lines. When,
A print dot counting unit that counts the number of print dots for each dot line, a print dot number storage unit that stores the print dot number, a paper feed motor that drives the paper, and dot lines before and after the dot line being printed. And a print control unit that controls the drive speed of the paper feed motor from the number of print dots.

Further, when the print control unit of the line type thermal printer of the present invention has a difference of a predetermined amount or more between the print dot number of the dot line currently being printed and the print dot number of the next dot line, There may be provided means for controlling so that the drive of the paper feed motor is stopped for a predetermined time after the completion of the dot line printing which is currently being printed, and immediately after that, the drive of the paper feed motor is started.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 includes a line-type thermal head 1 composed of a plurality of heating elements capable of driving a predetermined number at a time and a plurality of dot lines. A print pattern development unit 3 that stores print information, a print dot counting unit 4 that counts the number of print dots for each dot line, a print dot number storage unit 5 that stores the number of print dots, and a paper feed motor that drives the paper. 6 and the number of printing dots of the dot line currently being printed and the number of printing dots of the next dot line are more than a predetermined amount, the paper feed motor is driven for a predetermined time after the printing of the dot line currently printing Stop printing and start driving the paper feed motor immediately after that, based on the number of dots printed before and after the dot line being printed. Composed of print controller 2 which controls the driving speed of Domota 6.

The line type thermal head 1 has minute heating elements arranged in a line and has a number of heating elements corresponding to the width of the printing paper. Since the line-type thermal head 1 in this embodiment has 8 heating elements per 1 mm, it has 528 heating elements since the printing width is 66 mm. Since the density of the heating elements of the line type thermal head 1 is 8 per 1 mm, the paper feed pitch is also 1 m.
There are 8 steps per m. Line type thermal head 1
Power is supplied to each sheet feeding step (one dot line). Data about which heating element of the line-type thermal head 1 is energized to develop a color is stored in the print pattern developing unit 3 in advance. The dot line pattern data stored in the print pattern development unit 3 is transferred to the print dot counting unit 4 according to an instruction from the print control unit 2. The number of print dots counted by the print dot counting unit 4 is stored in the print dot number storage unit 5. When printing is started, the print control unit 2 transfers the dot line pattern data of the print pattern development unit 3 corresponding to the dot line to be printed now to the line type thermal head 1 and, at the same time, from the print dot number storage unit 5. The number of print dots of the dot line to be printed now and the number of print dots of the dot line to be printed next are read out, and the frequency is set so as to be a motor frequency within a range that the operation of the paper feed motor 6 can follow. An operation timing signal is output to the paper feed motor 6.

FIG. 2 shows the operation timing of the paper feed motor 6 in this embodiment when printing the print pattern as shown in FIG. The operation of this embodiment will be described in more detail with reference to FIGS. 2 and 3 together with FIG. The paper feed motor 6 is a stepping motor and rotates so that the paper is fed every dot line in response to an operation timing signal from the print control unit 2. However, a permanent magnet is often used in the rotating rotor portion of the stepping motor, and the rotation moment is relatively large. Therefore, a sudden change in the operation timing signal cannot be followed up, and there is a case where step out or resonance occurs. That is, when the frequency suddenly changes from one frequency to another, the operation of the paper feed motor becomes unstable, which leads to disturbance of printing and increase of noise.

When printing a print pattern as shown in FIG. 3, assuming that the maximum number of dots that can be energized at one time is three, the number of energized divisions from the first dot line to the eleventh dot line is 1, 1, 1, 6, 6,
It becomes 1,1,1,1,1,1. The paper feed motor has a maximum operating frequency of 500 pps (cycle 2 mse).
In the case of c), when the energization time for one division is 1 msec, the operation is performed at the maximum operating frequency up to two divisions. When the number of divisions increases or decreases, the motor operating frequency (operating cycle) changes. In the example of FIG. 3, the motor operating frequency from the first dot line to the third dot line is 5 because the number of divisions is 1.
While it is 00 pps, the fourth dot line has a division number of 6, and the frequency drops to 167 pps. Also, when moving from the 5th dot line to the 6th dot line, 6
The motor operating frequency is 1 because it changes from 1 division to 1 division.
It goes up from 67pps to 500pps. The paper feed motor cannot follow the increase / decrease of the frequency, which may cause a phenomenon such as resonance or step out, which disturbs the printing and increases noise.

In this embodiment, as shown in FIG. 2, the print dot number of the third dot line and the print dot number of the fourth dot line are read from the print dot number storage unit 5 and compared by the print control unit 2. Since the difference is large, the paper feed motor 6 is driven 4 msec after printing the third dot line. Further, the print dot number storage unit 5 stores the print dot number of the fifth dot line and the print dot number of the sixth dot line.
Since the difference is large in comparison with that read out from the print control unit 2, the paper feed motor 6 is driven 4 msec after printing the sixth dot line.

[0012]

As described above, according to the present invention,
When the difference between the number of print dots of the dot line currently being printed and the number of print dots of the next dot line is more than a predetermined amount,
Stabilize the operation of the paper feed motor by driving the paper feed motor for a predetermined time without immediately driving after the completion of dot line printing currently being printed,
Print disturbances and noise can be suppressed.

[Brief description of drawings]

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

FIG. 2 is a diagram showing the operation timing of the paper feed motor of this embodiment.

FIG. 3 is a diagram showing an example of a print pattern.

FIG. 4 is a diagram showing an operation timing of a conventional paper feed motor.

[Explanation of symbols]

 1 Line type thermal head 2 Print control unit 3 Print pattern development unit 4 Print dot counting unit 5 Print dot number storage unit 6 Paper feed motor

Claims (3)

[Claims] 1. A line-type thermal head comprising a plurality of heating elements capable of driving a predetermined number at the same time, and a print pattern developing section for storing print patterns of a plurality of dot lines,
A print dot counting unit that counts the number of print dots for each dot line, a print dot number storage unit that stores the print dot number, a paper feed motor that drives the paper, and dot lines before and after the dot line being printed. And a print control unit that controls the drive speed of the paper feed motor based on the number of print dots of the line type thermal printer. 2. When the print control unit has a difference of a predetermined amount or more between the number of print dots of the dot line currently being printed and the number of print dots of the next dot line, the printing of the dot line currently being printed is completed. 2. The line type thermal printer according to claim 1, further comprising means for controlling so that the driving of the paper feed motor is stopped for a predetermined time and the driving of the paper feed motor is started immediately after that. 3. A line-type thermal printer having a line-type thermal head composed of a plurality of heating elements capable of driving a predetermined number at the same time, storing a print pattern of a plurality of dot lines and counting the number of print dots for each dot line. When the number of print dots of the dot line currently being printed is different from the number of print dots of the next dot line by a predetermined amount or more, the number of print dots is stored The drive speed of the paper feed motor is determined from the number of dots printed before and after the dot line being printed so that the drive of the paper feed motor is stopped for a predetermined time and the drive of the paper feed motor is started immediately after that. A method for driving a paper feed motor of a line type thermal printer characterized by controlling.