JP2003039776A - Thermal printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent intrusion of dust into a printer body. SOLUTION: An exhaust fan 24 rotates constantly to discharge air from the inside of a body case 1 to the outside. A first suction fan 20 rotates depending on the temperature of a thermal head 35. A second suction fan 21 rotates upon stoppage of the first suction fan 20 and stops upon rotation thereof. The volume of air flow B, C from each fan 20, 21 is set larger than the volume of air flow D from the exhaust fan 24. Consequently, when a case cover 12 is at a close position, a positive pressure with respect to the atmospheric pressure is produced in the body case 11 even if the exhaust fan 24 is rotating by rotating any one suction fan thus preventing intrusion of dust into the body case 11 from the outside.

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 which operates an intake fan according to the temperature of a thermal head to suck air outside the printer into the printer to cool the thermal head. It concerns printers.

[0002]

2. Description of the Related Art Conventionally, in a thermal printer, an intake fan that operates according to the head temperature is provided near the thermal head, and this intake fan sucks air from outside the printer body into the printer body to cool the thermal head. ing. Further, an exhaust fan that discharges the air inside the printer body to the outside of the printer body is continuously operated, and heat and dust generated inside the printer body are discharged to the outside of the printer body.

[0003]

However, in the thermal printer as described above, only the exhaust fan is operated when the temperature of the thermal head is low, so that the inside of the printer main body becomes a negative pressure with respect to the atmospheric pressure. Therefore, there is a problem that dust easily enters the inside of the printer body from the outside of the printer body. Further, even when the loading chamber is opened when loading a recording medium such as roll paper into the loading chamber formed inside the printer main body, there is a problem that dust easily enters the inside of the printer main body from outside the printer main body.

The present invention has been made to solve the above problems, and the inside of the printer body is kept at atmospheric pressure regardless of the rotation of the cooling intake fan of the thermal head and the opening of the loading chamber for loading the recording medium. It is an object of the present invention to provide a thermal printer in which dust is prevented from entering the inside of the printer body by making the pressure positive.

[0005]

In order to achieve the above object, the thermal printer of the present invention is a thermal printer which records an image on a recording medium conveyed by using a thermal head in which a plurality of heating elements are arranged. , The exhaust fan that rotates continuously and discharges the air from the inside of the printer to the outside of the printer, and rotates according to the temperature of the thermal head,
A first intake fan that sucks air from the outside of the printer body to the inside of the printer body, and a second intake fan that rotates according to the rotation state of the first intake fan and sucks air from the outside of the printer body to the inside of the printer body The amount of intake air from the outside of the printer main body is made larger than the amount of exhaust air so that the inside of the printer main body becomes a positive pressure relative to the atmospheric pressure. Each of the first intake fan and the second intake fan has an air volume equal to or greater than that of the exhaust fan, and stops the second intake fan while the first intake fan is rotating and the second intake fan when the first intake fan is stopped. It is preferable to rotate the intake fan. Also, the second intake fan has an air volume equal to or greater than that of the exhaust fan,
It is preferable to rotate continuously. Further, the printer includes a loading lid that opens and closes when the recording medium is loaded into the printer body, and a detection unit that detects the opening and closing of the loading lid. When it is detected that the loading lid is open, the first intake fan and the It is preferable to rotate the second intake fan at the same time.

[0006]

1 and 2 are a schematic diagram and a block diagram showing the configuration of a thermal printer according to the present invention.
The main body case 11 of the thermal printer 10 includes a case lid 1
2, a paper discharge port 13, a first opening 14, a second opening 15, and an exhaust port 16 are provided. The case lid 12 is rotatably supported by a hinge (not shown), and the case 1
1 moves in the direction of arrow A between a closed position that covers the opening of the roll paper loading chamber 17 formed inside and an open position that opens.

The first and second openings 14 and 15 are provided with a first intake fan 20 and a second intake fan 21 for introducing air from outside the main body case 11 into the main body case 11. Filters 22 and 23 are arranged between the openings 14 and 15 and the intake fans 20 and 21, respectively, and remove dust and the like contained in the introduced air. First
Below the intake fan 20, a thermal head 3 described later is provided.
The heat sink 46 of No. 5 is arranged, and the main body case 1
1. Air introduced from the outside is blown toward the heat sink 46. An exhaust fan 2 for discharging air from the inside of the main body case 11 to the outside of the main body case 11 is provided at the exhaust port 16.
4 are provided.

Each fan 20, 21, 24 is a driver 2
It is connected to the system controller 30 via 6, 27, 28, and each rotation is controlled by the system controller 30. The air volumes of the air flows B and C by the intake fans 20 and 21 are set to be larger than the air volumes of the air flow D by the exhaust fan 24. As a result, when the case lid 12 is in the closed position, even if the exhaust fan 24 is rotating, by rotating either one of the intake fans, the inside of the main body case 11 becomes a positive pressure with respect to the atmospheric pressure.

Further, when the intake fans 20 and 21 rotate simultaneously, that is, the air volume of the air flow B + C is the opening of the roll paper loading chamber 17 when the air volume of the air flow D by the exhaust fan 24 and the case lid 12 are opened. It is set to be larger than the sum of the volume of air discharged from the section.
As a result, even when the case lid 12 is in the open position, the inside of the main body case 11 becomes a positive pressure relative to the atmospheric pressure by rotating the intake fans 20 and 21 at the same time.

The roll paper loading chamber 17 is loaded with a recording paper roll 31a obtained by winding a long thermosensitive recording paper 31 into a roll. A case lid 1 is provided on the side of the roll paper loading chamber 17.
A case lid opening / closing detection sensor 32 for detecting whether or not 2 is in the closed position is provided. The case lid opening / closing detection sensor 32 inputs a case lid opening signal to the system controller 30 when the case lid 12 is not in the closed position. The roll paper loading chamber 17 is provided with a paper feed mechanism (not shown), and when the recording paper roll 31a is loaded and the case lid 12 is at the closed position, the thermal recording paper 31 is delivered from the roll paper loading chamber 17.

A transport roller pair 34, a thermal head 35, a platen roller 36, are provided in the transport path of the thermal recording paper 31.
A pair of cutters 37, paper discharge rollers 38, and the like are arranged. The transport roller pair 34 and the paper discharge roller pair 38 are a pair of rollers, one of which is a capstan roller 34a, 38a, and the other of which is a pinch roller 34b, 38b. When the tip of the thermal recording paper 31 reaches the position of each roller pair 34, 38, the pinch rollers 34b, 38b move to nip the thermal recording paper 31. Each capstan roller 34a, 38
A conveyance motor 39 is connected to a. The carry motor 39 is connected to the system controller 30 via a motor driver 40, and
Controls the rotation of the carry motor 39 via the motor driver 40.

The thermal head 35 is arranged above the conveying path of the thermal recording paper 31. A thermistor 45 for head temperature measurement and a heat sink 46 for heat dissipation are provided above the thermal head 35.
At a position facing the thermal recording paper 31, a heating element array 35a in which a large number of heating elements are arranged in a line along the width direction of the thermal recording paper 31 is provided. The thermal head 35 is connected to the system controller 30 via a head driver 47.

The system controller 30 has a communication I / F.
An external device 49, for example, a personal computer or the like, is connected via 48, and communication I
Print data is input via / F48. The system controller 30 causes each heating element of the heating element array 35a to generate a predetermined temperature in accordance with the print data in synchronization with the conveyance of the thermal recording paper 31, and supplies thermal energy to the thermal recording paper 31 to develop color.

The thermistor 45 is the system controller 3
It is connected to 0 and inputs the measured head temperature Th of the thermal head 35 to the system controller 30.
The system controller 30 drives the first intake fan 20 according to the head temperature Th of the thermal head 35,
Airflow B is blown onto the heat sink 46 to cool the thermal head 35.

The platen roller 36 is a thermal head 3.
It is arranged below the conveyance path of the thermosensitive recording paper 31 so as to face the sheet No. The platen roller 36 has a shift mechanism 51.
Is provided, and the thermal head 35 and the thermal recording paper 3 are provided.
1 is selectively set between a print position in which 1 and 1 are brought into contact with each other with an appropriate contact pressure and a retracted position in which the thermal recording paper 31 is separated and retracted downward. The platen roller 36 is driven and rotated by the conveyance of the thermosensitive recording paper 31 at the time of printing, and stabilizes the contact state between the thermosensitive recording paper 31 and each heating element of the heating element array 35a. Further, the platen roller 36 is
At the time of paper feeding and paper ejection, a gap is formed between the thermal recording paper 31 and the thermal head 35 by moving to the retracted position so as not to hinder the movement of the thermal recording paper 31.

The cutter 37 is connected to the system controller 30 via a cutter driver 52. The system controller 30 drives and controls the cutter 37 via the cutter driver 52 to print the printed thermal recording paper 31.
Is cut in place. The paper discharge roller pair 38 is rotationally driven by the conveyance motor 39, and discharges the cut thermal recording paper 31 from the paper discharge port 13. Although not shown in order to prevent the drawing from becoming complicated, a guide member is appropriately provided in the conveyance path of the thermal recording paper 31. The thermosensitive recording paper 31 delivered from the recording paper roll 31a moves along the guide path along these guide members.

Next, the operation of the above embodiment will be described. FIG. 3 shows each fan 20, 21,
14 is a flowchart illustrating a driving state of No. 24. When the power of the thermal printer 10 is turned on, the exhaust fan 24 and the second intake fan 21 start rotating. At this time, the second
The air volume of the air flow C by the intake fan 21 is equal to that of the exhaust fan 2
4 is set to be larger than the air flow D of the air flow D, and the inside of the main body case 11 has a positive pressure with respect to the atmospheric pressure. This prevents dust from entering the inside of the body case 11 from the outside of the body case 11.

When print data is input from the external device 49 via the communication I / F 48, printing is started according to a predetermined print sequence. Then, the head temperature T of the thermal head 35 is set by the thermistor 45.
h is measured. When the head temperature Th is higher than the predetermined value, the first intake fan 20 is rotated and the second intake fan 21 is stopped. At this time, the air volume of the air flow B from the first intake fan 20 is set to be larger than the air volume of the air flow D from the exhaust fan 24. Head 35
Can be cooled. When the head temperature Th becomes equal to or lower than the predetermined value, the first intake fan 20 stops and the cooling of the thermal head 35 ends. Simultaneously with the stop of the first intake fan 20, the second intake fan 21 rotates and the main body case 11
The inside is kept at positive pressure relative to atmospheric pressure.

When the printing is completed, the thermistor 4 is restarted.
5, the head temperature Th of the thermal head 35 is measured. When the head temperature Th is higher than the predetermined value, the first intake fan 20 is rotated and the second intake fan 21 is stopped in the same manner as described above to keep the inside of the main body case 11 at a positive pressure with respect to the atmospheric pressure. Meanwhile, the air flow B is blown toward the heat sink to cool the thermal head 35. When the head temperature Th becomes equal to or lower than the predetermined value, the first intake fan 20 stops and the cooling of the thermal head 35 ends. Simultaneously with the stop of the first intake fan 20, the second intake fan 21 rotates to keep the inside of the main body case 11 at a positive pressure with respect to the atmospheric pressure until the next print data is input.

FIG. 4 is a flow chart for explaining the driving states of the fans 20, 21, 24 when the case lid 12 is opened and closed. When the power of the thermal printer 10 is turned on,
The exhaust fan 24 and the second intake fan 21 start rotating. At this time, the inside of the main body case 11 has a positive pressure with respect to the atmospheric pressure, and the main body case 1 is exposed from the outside of the main body case 11.
1. No dust will enter the inside.

When the opening / closing of the case lid 12 is detected by the case lid opening / closing detection sensor 32, the first and second intake fans 20 and 21 rotate simultaneously. At this time, the air volume of the air flow B + C by the first and second intake fans 20, 21 is
Since it is set to be larger than the sum of the air volume of the air flow D by the exhaust fan 24 and the air volume discharged from the opening of the roll paper loading chamber 17, the inside of the main body case 11 becomes a positive pressure with respect to the atmospheric pressure. . As a result, even when the case lid 12 is opened, the main body case 11 is exposed from outside the main body case 11.
No dust will enter the inside.

The recording paper roll 31a is placed in the roll paper loading chamber 17
And the case lid 12 is closed, the head temperature Th of the thermal head 35 is measured by the thermistor 45. Then, in the same manner as described above, when the head temperature Th is higher than the predetermined value, the first intake fan 20 is rotated and the second intake fan 21 is stopped, so that the main body case 1
1 While keeping the inside of the thermal pressure positive with respect to the atmospheric pressure, the airflow B is blown toward the heat sink 46 to
Cool 5 Further, when the head temperature Th becomes equal to or lower than a predetermined value, the second intake fan 21 rotates at the same time as the first intake fan 20 stops, and the inside of the main body case 11 is maintained in a positive pressure state with respect to the atmospheric pressure.

In the above embodiment, the first intake fan and the second intake fan are intermittently rotated according to the head temperature Th of the thermal head. However, as shown in FIG. 21 is continuously rotated, and the first intake fan 2 is rotated according to the head temperature Th of the thermal head 35.
Only 0 may be intermittently rotated.

[0024]

As described above, according to the thermal printer of the present invention, the exhaust fan, which rotates continuously and discharges air from the inside of the printer body to the outside of the printer body, rotates according to the temperature of the thermal head. A first intake fan for sucking air from outside the printer body into the printer body;
It has a second intake fan that rotates according to the rotation status of the intake fan and sucks air from the outside of the printer body to the inside of the printer body. Since the pressure is positive with respect to the atmospheric pressure, it is possible to prevent dust from entering the inside of the printer body.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the configuration of a thermal printer embodying the present invention.

FIG. 2 is a block diagram showing a circuit configuration of a thermal printer.

FIG. 3 is a flowchart illustrating the operation of each fan during printing.

FIG. 4 is a flowchart illustrating the operation of each fan when the case lid is opened and closed.

FIG. 5 is a flowchart illustrating the operation of each fan during printing according to the second embodiment.

[Explanation of symbols]

10 Thermal printer 11 body case 12 case lid 13 Paper exit 14 First opening 15 Second opening 16 exhaust port 17 Roll paper loading room 20 First intake fan 21 Second intake fan 22,23 filter 24 exhaust fan 35 thermal head 45 thermistor 46 heat sink

Claims (4)

[Claims] 1. A thermal printer for recording an image on a conveyed recording medium using a thermal head in which a plurality of heating elements are arranged, which is continuously rotated to discharge air from the inside of the printer body to the outside of the printer body. An exhaust fan, a first intake fan that rotates according to the temperature of the thermal head, and sucks air from the outside of the printer body into the inside of the printer body;
It has a second intake fan that rotates according to the rotation status of the intake fan and sucks air from the outside of the printer body into the inside of the printer body. A thermal printer characterized by having a positive pressure relative to atmospheric pressure. 2. Each of the first intake fan and the second intake fan has an air volume equal to or greater than that of the exhaust fan,
While the first intake fan is rotating, stop the second intake fan,
The thermal printer according to claim 1, wherein the second intake fan is rotated while the first intake fan is stopped. 3. The thermal printer according to claim 1, wherein the second intake fan has an air volume equal to or greater than that of the exhaust fan and is continuously rotated. 4. A loading lid that opens and closes when a recording medium is loaded into the printer body, and a detection unit that detects opening and closing of the loading lid. When it is detected that the loading lid is open, 4. The thermal printer according to claim 1, wherein the first intake fan and the second intake fan are rotated at the same time.