JP2859182B2 - Thermal printer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line printer type thermal printer, and more particularly to a thermal printer capable of performing color gradation printing.

[0002]

2. Description of the Related Art FIG. 3 is a block diagram showing an example of a conventional thermal printer.

As shown in FIG. 3, a conventional line printer type thermal printer has a thermal head 11 having a plurality of heating elements arranged in a line and a print head 19 which receives print data 19 from a host device. A head drive circuit 14 for applying a voltage to each heating element, a platen 13 for transporting the thermal paper 12 colored by the thermal head 11, a transport motor 17 for driving the platen 13 via a timing belt 18, and a head Drive circuit 1
And a transport motor drive circuit 16 for supplying a current to the transport motor 17 in response to a signal from the controller 4.

In the thermal printer configured as described above, the transport motor 11 is controlled by the transport motor drive circuit 16.
By driving and rotating the platen 13, thermal paper
12 while continuously transporting 12 at a constant speed.
Input print data 19 for the print head to the head drive circuit 14.
You. The head drive circuit 14 to which the print data 19 has been input is
Heating element corresponding to print data 19 of thermal head 11
Is applied. This allows the thermal head
Since the temperature of the heating element to which the voltage of 11 is applied rises,
The part of the thermal paper 12 that is in contact with those heating elements is colored
I do. Applying voltage to the heating element for a certain period of time
Then, the head drive circuit 14 stops applying the voltage. 1
The dot printing for the dot line is completed and the thermal paper 12 becomes 1
If only a dot line is Ru is conveyed, the head driving circuit 1
No. 4 inputs the print data 19 for the next one dot line and repeats the above operation.

[0005]

In the conventional thermal printer as described above, the thermal paper is continuously conveyed at a constant speed.
Of the transport time for one dot line.
Electricity is applied to the corresponding heating element for dot printing at a fixed time.
Since pressure is applied, one heating element is continuously
If voltage is applied continuously to perform the
Sufficient coloring of thermal paper due to elevated temperature of heating element
You can make a dot up to the previous dot line
No voltage is applied because there is no printing, so
Voltage is applied to the heating element in the
When voltage is applied, it is sufficient within a certain time voltage application time
The temperature of the heating element does not rise in
This is sufficient and so-called dot missing occurs. Therefore, conventional
-In the case of a normal printer, the print quality sometimes drops due to missing dots.
Is inferior.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the conventional thermal printer, and to improve the prior dot line up to the previous dot line.
The heating element without dot printing is the dot mark of the next dot line
Even if you perform the character, make sure that a sufficient heat generation temperature is obtained.
Another object of the present invention is to provide a thermal printer capable of obtaining excellent print quality because no dot missing occurs .

[0007]

SUMMARY OF THE INVENTION A thermal printer according to the present invention includes a thermal head having a plurality of heating elements arranged in a row and a plurality of sensors for detecting respective temperatures of the plurality of heating elements. The temperature of each of the plurality of heating elements is monitored by inputting signals from the plurality of sensors, and the control of the voltage applied to each of the plurality of heating elements and the control of the conveyance of the printing paper are performed. A heat driving data processing circuit, a head driving circuit for applying a voltage to each of the plurality of heating elements in accordance with a signal from the heat generating data processing circuit, and a printing paper in response to a signal from the heat generating data processing circuit. And a transport motor drive circuit that supplies current to a transport motor that drives a platen that transports the paper.

[0008]

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

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a flowchart showing the operation of the embodiment of FIG.

In FIG. 1, a thermal head 1 has a plurality of heating elements arranged in a line and a plurality of sensors 10 for detecting the respective temperatures of the heating elements. The heating data processing circuit 5 receives a signal from each sensor 10 of the thermal head 1, monitors the temperature of each of the plurality of heating elements, and controls the voltage applied to each heating element of the thermal head 1. And control of the transfer of the thermal paper 2. The head drive circuit 4 receives a signal from the heat generation data processing circuit 5 and applies a predetermined voltage to each heating element of the thermal head 1. The transport motor drive circuit 6 receives a signal from the heat generation data processing circuit 5 and supplies a current to a transport motor 7 that drives a platen 3 that transports the thermal paper 2.

Next, the operation of the thermal printer configured as described above will be described with reference to FIGS.

When the print data 9 is input to the heat generation data processing circuit 5 (step 21 in FIG. 2), the heat generation data processing circuit 5 sends a heat generation start signal to the head drive circuit 4, and the head drive circuit 4 receives the print start signal. A voltage is applied to the head 1. Each heating element of the thermal head 1 generates heat (step 22). When each heating element of the thermal head 1 generates heat, the temperature is detected by the sensor 10 and sent to the heating data processing circuit 5, so that the heating data processing circuit 5 determines that each heating element of the thermal head 1 is heat sensitive.
Monitors whether the host vehicle has reached the predetermined temperature so as not to cause a color paper 2 (predetermined temperature) (step 23), when all of the heating element has reached, respectively it Jo Tokoro temperature, the feeding motor driving circuit 6 In response, a drive start signal is sent. When the drive start signal is input, the transport motor drive circuit 6
To supply the drive current to operate the transport motor 7. The transport motor 7 rotates the platen 3 via the timing belt 8 to transport the thermal paper 2 . Feeling at this time
The transport distance of the thermal paper 2 is determined by the size of the heating element of the thermal head 1.
This is the distance corresponding to the distance. During the transfer of thermal paper 2, heat generation
The data processing circuit 5 sends a signal to the head drive circuit 4.
Of the heating element corresponding to the input print data 9
The temperature at which the thermal paper 2 develops color (the printing temperature
The dot is printed by raising the heating element up to (degree) (step 24).

[0013] During this heating data processing circuit 5, the print data
The head drive circuit 4
, The application of a voltage to them is stopped. While the application of the voltage to the heating element of the thermal head 1 is stopped, the heating data processing circuit 5
Monitors the temperature of each heating element of the thermal head 1,
When the temperature of each heating element becomes lower than the predetermined temperature, a heating start signal is sent to the head drive circuit 4. As a result, the head drive circuit 4 restarts applying the voltage to the heating element of the thermal head 1. Thus, the temperature of each heating element of the thermal head 1 is maintained at a predetermined temperature.

When printing of one dot line is completed, the heat generation data processing circuit 5 sends a print end signal to the head drive circuit 4, and the head drive circuit 4 ends the application of voltage to each heating element of the thermal head 1. I do. At the same time, the heat generation data processing circuit 5 sends a transport end signal to the transport motor drive circuit 6, and the motor drive circuit 6 stops supplying the drive current to the transport motor 7 and supplies a holding current instead. I do. When receiving the supply of the holding current, the transport motor 7 holds the platen 3 via the timing belt 8,
The thermal paper 2 is held at the position where printing has been completed (step 2).
5). In this state, the heat generation data processing circuit 5
It is in a state of waiting for input of print data of the next dot line.

When the print data of the next dot line is input to the heat generation data processing circuit 5 , the thermal printer operates as described above.
Repeat the operation. If there is no print data for the next dot line
If not, the printing operation ends (step 26).

As described above, the thermal paper 2 is transported only when the temperatures of all the heating elements of the thermal head 1 reach the temperatures satisfying the predetermined temperatures, and the transport distance of the thermal paper 2 is set to the thermal head 1 distance. By setting the length to the size of the heating element , all the heat generated during dot printing
To allow the body to reach a sufficient exothermic temperature at any time,
Therefore, high quality printing results can be obtained because no dot missing occurs .

[0017]

As described above, the thermal printer according to the present invention comprises a thermal head including a plurality of sensors for detecting the temperatures of a plurality of heating elements arranged in a line, and the plurality of sensors. maintaining the temperature of the entire heating element to each predetermined temperature by a signal from, and 1 when the printing dot line has been completed to hold the thermal paper to the printing end position the print data of the next dot line entered when by providing the heating data processing circuit performs control so as to transport the length corresponding to thermal paper to the size of the heating elements of the thermal head, when the dot printing, all heating
Allows the body to reach a sufficient exothermic temperature at any time
Therefore, there is an effect that dot missing does not occur and a high quality printing result can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a flowchart showing the operation of the embodiment of FIG.

FIG. 3 is a block diagram illustrating an example of a conventional thermal printer.

[Explanation of symbols]

 1.1 Thermal Head 2.12 Thermal Paper 3.13 Platen 4.14 Head Drive Circuit 5 Heat Generation Data Processing Circuit 6.16 Transport Motor Drive Circuit 7.17 Transport Motor 8.18 Timing Belt 9.19 Print Data 10 Sensor 21 ~ 26 steps

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B41J 2/355-2/365 B41J 2/38

Claims (2)

(57) [Claims] 1. A thermal head having a plurality of heating elements arranged in a row and a plurality of sensors for detecting respective temperatures of the plurality of heating elements, and inputs signals from the plurality of sensors. A heating data processing circuit that monitors the temperature of each of the plurality of heating elements to thereby control the voltage applied to each of the plurality of heating elements and control the conveyance of the printing paper , By the sensor
All of the plurality of heating elements detected at a predetermined temperature
Transport of the printing paper only when it has reached
And a thermal printer. 2. A thermal head having a plurality of heating elements arranged in a row and a plurality of sensors for detecting respective temperatures of the plurality of heating elements, and inputs signals from the plurality of sensors. A heating data processing circuit that monitors the temperature of each of the plurality of heating elements to control the voltage applied to each of the plurality of heating elements and controls the conveyance of the printing paper; A head drive circuit that applies a voltage to each of the plurality of heating elements according to a signal from a data processing circuit, and a transport motor that drives a platen that transports the printing paper according to a signal from the heat generation data processing circuit. a conveying motor drive circuit for supplying a current Te, detected by the sensor
All of the plurality of heating elements reach a predetermined temperature.
Including carrying the printing paper only when
Thermal printer characterized in that.