JPH09123558A - Thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the printing quality of a thermal printer by detecting the steady stop of a sheet by the output supply stop of an encoder mounted at a platen, and rapidly effectively printing the stopped sheet, thereby remarkably reducing the influence to the printing speed. SOLUTION: When a controller 1 receives a command for designating the feeding of one dot line, the controller 1 supplies a drive pulse to a feed motor 2, and starts a platen stop detector. The motor 2 rotates the platen 3 by one dot line in response to the supply of the pulse, and feeds a heat sensitive sheet 8 by one dot line. The encoder 4 continuously generates pulses of the number responsive to the rotating amount of the platen 3 during the period of sheet feeding, and stops the pulses when the rotation of the platen 3 is stopped and the sheet feeding operation is finished. Then, when the detector detects the pulse stop, it drives a thermal head 5 to conduct a predetermined printing operation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer, and more particularly to a thermal printer in which the application start timing of the thermal head after paper feeding is improved.

[0002]

2. Description of the Related Art A schematic view of a conventional thermal printer is shown in FIG. 4, and the relationship between the paper feed and print timing is shown in the time charts of FIGS. 5 (a), 5 (b) and 5 (c).

As shown in FIG. 4, a conventional thermal printer includes a thermal head 5 for applying heat to the thermal paper 8 to change the color thereof for printing, and a platen 3 for feeding the thermal paper 8.
A head pressing spring 6 that presses the thermal head 5 against the platen 3, a feed motor 2 that rotationally drives the platen 3, and a controller 9 that controls driving of the feed motor 2 and application of the thermal head 5. I have it.

The conventional thermal printer thus constructed prints according to the print timing chart shown in FIG.

That is, the controller 9 outputs one drive pulse to the feed motor 2 to feed the thermal paper 8 by one dot line (FIG. 5A), and the platen 3
Is driven to feed the thermal paper 8 by one dot line (FIG. 5B), while the control unit 9 controls the static control timer in the control unit 9 in accordance with the output of the drive pulse for a predetermined time (static time). It is presumed that the thermal paper 8 has stopped (statically set) by measuring the constant time, and then the control unit 9 starts applying the thermal head 5 to perform printing (FIG. 5).
(C)).

[0006]

In the above-described conventional thermal printer, the paper is settled by waiting for a settling time after outputting one drive pulse for feeding the paper to the feed motor by one dot line. It is assumed that printing has started.

However, the time until the actual sheet is settled changes depending on the type of sheet, the pressing force of the thermal head against the platen, the surrounding environment, and the like. Therefore, the optimum value of the settling time is determined by evaluation or the like. Things are very difficult.

Particularly, when the settling time is shorter than the time required for actual sheet settling, printing is started during the operation of the paper, and white streaks occur in the print result, resulting in print quality. However, if the settling time is longer than the time required for actual sheet settling, there is a problem in that the printing speed is decreased.

An object of the present invention is to detect the stationary state of the paper by stopping the output supply of an encoder attached to the platen and perform printing quickly, thereby significantly reducing the influence on the printing speed as compared with the prior art. It is to provide a thermal printer capable of significantly improving print quality.

[0010]

SUMMARY OF THE INVENTION A thermal printer according to a first aspect of the present invention comprises a platen for feeding a thermal paper, a 1-dot line thermal head for applying heat to the thermal paper to discolor it for printing, and a platen for the platen. A feed motor for rotationally driving, a detecting means for detecting the rotation of the platen, and a platen for the platen according to a control signal from the outside.
And a control means for driving the thermal head by instructing the feed motor to drive the dot lines and monitoring the output of the detecting means to detect the stop of the rotation of the platen.

A thermal printer according to a second aspect of the present invention includes a platen for feeding the heat-sensitive paper, a 1-dot line thermal head for applying heat to the heat-sensitive paper to change the color for printing, and a feed motor for rotationally driving the platen. , An encoder for generating a number of pulses according to the rotation amount of the platen, and an instruction to the feed motor to drive the platen by one dot line in response to an external control signal, and the feed motor according to the instruction. And a control unit that receives the number of pulses corresponding to the rotation amount of the platen supplied from the encoder according to the rotation of the platen, detects the rotation stop of the platen, and drives the thermal head. There is.

[0012]

Next, embodiments of the present invention will be described with reference to the drawings.

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

The thermal printer of this embodiment is shown in FIG.
As shown in FIG. 3, a thermal head 5 that applies heat to the thermal paper 8 to change the color to print, a platen 3 that feeds the thermal paper 8, a head pressing spring 6 that presses the thermal head 5 against the platen 3, A feed motor 2 that drives the platen 3 to rotate, an encoder 4 that is mounted coaxially with the rotation axis of the platen 3 and that generates a number of pulses according to the amount of rotation of the platen 3, and outputs of the encoder 4 A control unit 1 for monitoring and controlling the drive of the feed motor 2 and the application of the thermal head 5 is provided.

The encoder 4 generates a number of pulses according to the amount of rotation of the platen 3. For example, the encoder 4 has a plurality of slits at equal intervals on the circumference of a disk, and the slits allow the platen 4 to rotate. In response, the light of the photo interrupter is passed to generate a pulse. Therefore, while the encoder 4 generates a number of pulses according to the rotation amount of the platen 3 while the platen 3 is rotating, the pulse generation is stopped together with the stop of the platen 3.

FIG. 2 is a block diagram showing the configuration of the control unit 1.

As shown in FIG. 2, the control unit 1 receives the output from the encoder 4 and detects the rotation stop of the platen 3 and the platen stop detecting unit 14, and receives the 1-dot line feed command to control the platen 3. A feed motor drive unit 12 that supplies a drive pulse to the feed motor 2 to feed only one dot line, and a thermal head drive unit 13 that drives the thermal head 5 to print one dot line.
And a control circuit 11 which receives a control signal or the like from the outside to operate the feed motor drive unit 12, the thermal head drive unit 13, and the platen stop detection unit 14.

FIG. 3 is a timing chart for explaining the print timing of the thermal printer of this embodiment.

The operation of the thermal printer of this embodiment will be described with reference to FIGS.

When the control unit 1 receives a command for instructing the feed of one dot line, the feed motor drive unit 12 supplies a drive pulse for driving the feed motor 2 to the feed motor 2 (FIG. 3A).
The platen stop detection unit 14 is activated.

In response to the supply of the drive pulse from the feed motor drive unit 12, the feed motor 2 is driven by the platen 3
Is rotated by 1 dot line to feed the thermal paper 8 by 1 dot line (FIG. 3 (b)).

During the paper feed period, the encoder 4 continues to generate the number of pulses corresponding to the rotation amount of the platen 3 (FIG. 3 (d)).

When the rotation of the platen 3 is stopped and the paper feeding operation is completed, that is, when the heat-sensitive paper 8 is stopped, the pulse supply from the encoder 4 is stopped. Therefore, the platen stop detector 14 detects this and the thermal head is detected. The drive unit 13 is activated (FIG. 3C), and the thermal head 5 is driven to perform the printing operation.

In this way, the thermal printer according to the present embodiment can detect the stationary state of the sheet by stopping the output supply of the encoder 4 attached to the platen 3, and can reliably and quickly print on the stationary sheet. As compared with the prior art, the effect on the printing speed can be significantly reduced, and the printing quality can be significantly improved.

[0025]

As described above, the thermal printer of the present invention can detect the stationary state of the sheet by stopping the output supply of the encoder attached to the platen, and reliably and quickly print on the stationary sheet. Therefore, there is an effect that the influence on the printing speed is remarkably reduced and the printing quality is remarkably improved as compared with the conventional case.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a configuration of a control unit of the thermal printer according to the present embodiment.

FIG. 3A is a time chart of a feed motor driving pulse, FIG. 3B is a time chart of paper operation, and FIG. 3C is a thermal head application time chart of an embodiment of a thermal printer of the present invention. ) Is a time chart of encoder output.

FIG. 4 is a block diagram showing a schematic configuration of a conventional thermal printer.

FIG. 5A is a time chart of a feed motor driving pulse, FIG. 5B is a time chart of paper operation, and FIG. 5C is a thermal head application time chart for a conventional thermal printer.

[Explanation of symbols]

 1, 9 Control unit 2 Feed motor 3 Platen 4 Encoder 5 Thermal head 6 Head pressing spring 7 Housing 8 Thermosensitive paper 91 Control circuit 92 Feed motor drive unit 93 Thermal head drive unit 94 Platen stop detection unit

Claims (2)

[Claims] 1. A platen for feeding a thermal paper, a 1-dot line thermal head for applying heat to the thermal paper to change the color for printing, a feed motor for rotationally driving the platen, and detection of rotation of the platen. Detecting means, and instructing the feed motor to drive the platen by one dot line in response to a control signal from the outside, monitoring the output of the detecting means, detecting the rotation stop of the platen, and detecting the thermal head. A thermal printer including a driving control unit. 2. A platen for feeding thermal paper, a 1-dot line thermal head for applying heat to the thermal paper to change the color for printing, a feed motor for rotationally driving the platen, and a rotation amount of the platen. An encoder that generates a corresponding number of pulses, and an instruction to the feed motor to drive the platen by one dot line according to a control signal from the outside. The feed motor is instructed to rotate the platen according to the instruction. A thermal printer comprising: a controller that receives a number of pulses according to the rotation amount of the platen supplied from an encoder, detects the rotation stop of the platen, and drives the thermal head.