JP2012183682A - Thermal transfer printer - Google Patents

Abstract

An object of the present invention is to provide a thermal transfer printer having a high cooling capacity at low cost.
A thermal transfer printer according to the present invention includes a paper transport roller for applying a transport force to a print paper, a paper transport motor for applying a rotational driving force to the paper transport roller, and a thermal transfer of ink to the print paper. The thermal head 13 that is attached to the thermal head 13, the heat sink 12 that radiates heat from the thermal head 13, the cooling fan 11 that cools the heat sink 12, and the rotational driving force of the paper transport motor 1 are transmitted to the cooling fan 11. A driving force transmission mechanism is provided.
[Selection] Figure 1

Description

  The present invention relates to a thermal transfer printer, and more particularly to a technique for efficiently suppressing a temperature rise of a thermal head.

  In a conventional thermal transfer (sublimation type, thermal) printer, a film-like ink sheet wound as an ink ribbon and dedicated paper such as roll paper and cut paper are sandwiched between a platen roller and a heater line of a thermal head, and are crimped. One printed matter is created by thermal transfer (sublimation) of ink dye on paper.

  At this time, the temperature of the thermal head rises due to the accumulation of heat from the thermal head that does not contribute to the thermal transfer of the ink dye. When the temperature reaches a certain level or more, printing defects (density unevenness, tailing, wrinkles, etc.) ) Occurs. Therefore, how to efficiently remove the heat of the thermal head in a short time is one of the important technical issues in thermal transfer printers.

  From this point of view, various methods have been proposed as means for quickly radiating the heat generated by the thermal head. As an example of the prior art, in the technique shown in Patent Document 1, a heat pipe is formed integrally with a substrate portion of a thermal head instead of a heat radiating fin made of aluminum or the like, and the bottom surface of the heat pipe is used as an action of the thermal head. It is comprised so that it may become a surface. On the other hand, the efficiency of heat transport is improved by attaching heat radiation fins to the heat pipe, and as a result, the heat radiation efficiency is improved.

Japanese Patent No. 2936584

  According to the method of integrally forming the heat pipe and the thermal head shown in Patent Document 1, since the mounting surface of the thermal head is a heat pipe, the mounting surface is compared with a heat radiating fin made of aluminum or the like. It is difficult to obtain a satisfactory flatness, resulting in poor printing.

  Further, in order to use the heat pipe efficiently, it is necessary to dispose the heat dissipating part above the heating part, and there are restrictions on the layout of the thermal head as compared with the heat dissipating fin made of aluminum or the like.

  Further, even if the heat transport efficiency of excess heat of the thermal head is increased by the heat pipe, it is an important issue to increase the cooling capacity for cooling the heat after heat transport.

  On the other hand, as a means for improving the cooling capacity, a method of increasing the maximum air volume and static pressure by increasing the number of cooling fans is generally used, but there are problems such as an increase in cost and power consumption due to the addition of cooling fans. is there.

  In view of the above-described problems, an object of the present invention is to provide a thermal transfer printer having a high cooling capacity at low cost.

  The thermal transfer printer of the present invention includes a paper transport roller that applies a transport force to a print paper, a paper transport motor that applies a rotational driving force to the paper transport roller, a thermal head that thermally transfers ink to the print paper, and the thermal transfer printer. A heat sink that is integrally attached to the head and radiates heat from the thermal head, a cooling fan that cools the heat sink, and a driving force transmission mechanism that transmits the rotational driving force of the paper transport motor to the cooling fan.

  Since the thermal transfer printer of the present invention includes a driving force transmission mechanism that transmits the rotational driving force of the paper transport motor to the cooling fan, the cooling fan can be driven without providing a dedicated motor, resulting in a low-cost thermal transfer printer. .

1 is a configuration diagram of a thermal transfer printer according to Embodiment 1. FIG. FIG. 5 is a diagram for explaining a printing operation of the thermal transfer printer according to the first embodiment. FIG. 6 is a diagram illustrating a sheet returning operation of the thermal transfer printer according to the first embodiment. FIG. 6 is a configuration diagram illustrating a main part of a thermal transfer printer according to a second embodiment. FIG. 6 is a configuration diagram illustrating a main part of a thermal transfer printer according to a second embodiment. FIG. 6 is a configuration diagram illustrating a main part of a thermal transfer printer according to a third embodiment.

(Embodiment 1)
<Configuration>
FIG. 1 is a configuration diagram of the thermal transfer printer according to the first embodiment. In the thermal transfer printer according to the present embodiment, the paper transport roller 5 and the pinch roller 4 are paired to sandwich the print paper 8, and the print paper 8 is transported by these rotations. A paper transport roller drive gear 3 is provided at the end of the paper transport roller 5, and the paper transport roller drive gear 3 and the paper transport roller 5 rotate together. A rotational driving force of the paper transport motor 1 is applied to the paper transport roller drive gear 3 via the belt 2. That is, when the paper transport motor 1 rotates, the paper transport roller 5 rotates according to the rotation direction.

  The thermal transfer printer includes a thermal head 13 that thermally transfers ink to the print paper 8. The thermal head 13 is paired with the platen roller 15, sandwiches the print paper 8 and the ink sheet 14, supplies heat to the ink sheet 14, and thermally transfers the dye on the ink sheet 14 onto the print paper 8. The ink sheet 14 is wound as an ink ribbon before and after the thermal head 13.

  On the thermal head 13, a heat sink 12 that dissipates heat accumulated in the thermal head 13 is provided. The heat radiated from the heat sink 12 is cooled by the cooling fan 11.

  Further, the thermal transfer printer according to the present embodiment includes a driving force transmission mechanism that transmits the rotational driving force of the paper transport motor 1 to the cooling fan 11. The driving force transmission mechanism includes an idle gear 6, a planetary gear 7, a first driving gear train 9, and a second driving gear train 10. The first and second drive gear trains 9 and 10 are each composed of a plurality of gears. In FIG. 1, only the gears at both ends of the gear train are shown, and the rest are omitted by dotted lines (in the subsequent drawings). The same). Such a configuration is an example of a driving force transmission mechanism, and the driving force of the paper transport motor 1 may be transmitted to the driving unit of the cooling fan 11 by another configuration.

  The idle gear 6 meshes with the paper transport roller driving gear 3 and the planetary gear 7, and transmits the rotational driving force of the paper transport roller driving gear 3 to the planetary gear 7. The planetary gear 7 includes a fixed gear that meshes with the idle gear 6 and a rotational gear that is rotatably held while meshing with the fixed gear. It meshes with one of the two drive gear trains 10. More specifically, the gear train to be meshed is switched according to the rotation direction of the paper transport motor 1.

  The first drive gear train 9 and the second drive gear train 10 mesh with the drive portion of the cooling fan 11 at the end opposite to the side meshed with the planetary gear 7, and the rotational drive force of the planetary gear 7. Drives the cooling fan 11 via one of the drive gear trains 9 and 10 meshed therewith. The second drive gear train 10 is composed of an odd number of gears greater than or less than the first drive gear train 9.

<Operation>
Yellow (Y), magenta (M), and cyan (Cy) are applied to the ink ribbon 14, and when Y is thermally transferred to the print paper 8, the print paper 8 is returned by the same distance as that conveyed during printing. Thermal transfer is performed in the same manner as Y. Thereafter, Cy is thermally transferred in the same procedure to form an image. In one image forming process including such a printing operation and a sheet returning operation, the sheet transport motor 1 rotates in both directions.

  The printing operation of the thermal transfer printer will be described with reference to FIG. When the paper transport motor 1 rotates counterclockwise, the paper transport roller driving gear 3 interlocked with the paper transport motor 1 via the belt 2 also rotates counterclockwise, and the paper transport roller 5 rotates counterclockwise. As a result, the print paper 8 is conveyed leftward in the drawing.

  When the paper transport roller drive gear 3 rotates counterclockwise, the idle gear 6 meshed with the paper transport roller drive gear 3 rotates clockwise, and the fixed gear of the planetary gear 7 rotates counterclockwise. The rotating gear of the planetary gear 7 rotates clockwise. Since the rotating gear of the planetary gear 7 meshes with the gear at the end of the first drive gear train 9 during the printing operation, the drive unit of the cooling fan 11 rotates via the first drive gear train 9 to cool the planetary gear 7. The fan 11 is driven.

  Next, the sheet returning operation of the thermal transfer printer will be described with reference to FIG. At this time, the rotating gear of the planetary gear 7 meshes with the second drive gear train 10. When the paper transport motor 1 rotates in the clockwise direction, the paper transport roller driving gear 3 interlocked with the paper transport motor 1 through the belt 2 also rotates in the clockwise direction, and the paper transport roller 5 rotates in the clockwise direction. Thereby, the print paper 8 is conveyed rightward in the drawing.

  The sheet conveying roller drive gear 3, the idle gear, the fixed gear and the rotating gear of the planetary gear 7 rotate in directions opposite to the rotation direction during printing. The rotation gear of the planetary gear 7 rotates counterclockwise, the drive unit of the cooling fan 11 rotates via the second drive gear train 10, and the cooling fan 11 is driven.

  Here, by making the number of gears constituting the second drive gear train 10 an odd number more or less than the number of gears constituting the first drive gear train 9, the rotation direction of the gears in the final stage of the gear train is made uniform. The cooling fan 11 can always be rotated in one direction regardless of the rotation direction of the paper transport motor 1.

<Effect>
The thermal transfer printer of this embodiment includes a paper transport roller 5 that applies a transport force to the print paper 8, a paper transport motor 1 that applies a rotational driving force to the paper transport roller 5, and a thermal that thermally transfers ink to the print paper 8. A head 13, a heat sink 12 that is integrally attached to the thermal head 13, dissipates the thermal head 13, a cooling fan 11 that cools the heat sink 12, and a driving force that transmits the rotational driving force of the paper transport motor 1 to the cooling fan 11. Since the transmission mechanism is provided, it is not necessary to provide a dedicated motor for driving the cooling fan 11, and the cost can be reduced.

  In the thermal transfer printer according to the present embodiment, the paper transport motor 1 applies a bi-directional rotational driving force to the paper transport roller 5, and the driving force transmission mechanism has a first end engaged with the driving unit of the cooling fan 11. One drive gear train 9, one end meshed with the drive unit of the cooling fan 11, the second drive gear train 10 configured with an odd number of gears different from the first drive gear train 9, and the rotation of the paper transport motor 1 Since the driving force is transmitted and the planetary gear 7 meshes with the other end of either the first drive gear train 9 or the second drive gear train 10 according to the rotation direction of the paper transport roller 5, the paper transport is provided. The cooling fan 11 can be rotated in one direction regardless of which direction the motor 1 rotates.

(Embodiment 2)
FIG. 4 is a diagram illustrating a main configuration of the thermal transfer printer according to the second embodiment. The thermal transfer printer according to the second embodiment is different from the first embodiment in that a lever gear 16 is used instead of the idle gear 6. The lever gear 16 is provided so as to mesh between the paper transport roller drive gear 3 and the planetary gear 7, but can freely rotate to a position where it does not mesh.

  As a rotation mechanism of the lever gear 16, for example, as shown in FIG. 4, a solenoid 17 and a spring 18 whose movable part expands according to the excitation state can be used. The lever 18 is urged by a spring 18 to a position where the lever gear 16 meshes with the paper transport roller driving gear 3 and the planetary gear 7, and when the solenoid 17 is extended, the lever is pushed and the lever gear 16 is moved to the paper transport roller driving gear 3 and the planetary gear. Rotate to a position that does not mesh with 7. Since the rotational driving force of the paper transport motor 1 is transmitted to the cooling fan 11 when the lever gear 16 is engaged, it is not transmitted when the lever gear 16 is not engaged. Therefore, the solenoid 17 is extended according to desired conditions, thereby cooling. The driving / non-driving of the fan 11 can be switched.

  The lever gear 16 rotating mechanism described above is merely an example. For example, a cam (not shown) that moves up and down any of the thermal head 13, the platen roller 15, or the pinch roller 4 and the rotation of the lever gear 16 are synchronized. You may use the mechanism to make.

<Effect>
The thermal transfer printer of the present embodiment is provided integrally with the paper transport roller 5, and includes a paper transport roller drive gear 3 that transmits the rotational driving force received from the paper transport motor 1 to the paper transport roller 5, and the paper transport roller drive gear. 3 and the planetary gear 7 are further provided with a lever gear 16 that is movably arranged at the meshing position and the non-meshing position of both gears, so that the cooling fan 11 is driven / non-driven by the rotation of the lever gear 16. Can be switched.

(Embodiment 3)
<Configuration>
FIG. 6 is a diagram illustrating a main configuration of the thermal transfer printer according to the third embodiment. The thermal transfer printer according to the third embodiment includes a cooling fan 19 with a motor driven by a built-in motor and auxiliary cooling fans 11 a and 11 b as cooling fans for cooling the heat sink 12.

  The auxiliary cooling fans 11a and 11b correspond to the cooling fan 11 described in the first and second embodiments, and rotate by receiving the rotational driving force of the paper transport motor 1 by the driving force transmission mechanism. The driving force transmission mechanism is the same as in the first and second embodiments.

  Specifically, the synchronization gear 20a (synchronization gear 20b) meshes with the first drive gear train 9 (second drive gear train 10), and the synchronization gears 20a and 20b are connected by the synchronization shaft 23 and synchronized. ing. When the synchronous gears 22a and 22b rotate, the auxiliary cooling fan drive gear 20a meshed with the synchronous gear 22a and the auxiliary cooling fan drive gear 20b meshed with the synchronous gear 22b rotate, and the auxiliary cooling fans 11a and 11b rotate. .

  Here, the gear train in the driving force transmission mechanism between the paper transport roller drive gear 3 and the auxiliary cooling fans 21a and 21b so that the rotation speed of the auxiliary cooling fans 11a and 11b exceeds the maximum rotation speed of the motorized cooling fan 19. The number of teeth is configured. Further, the auxiliary cooling fans 21a and 21b are configured so that the air volume generated by the auxiliary cooling fans 21a and 21b exceeds the air volume generated by the motor-equipped cooling fan 19. As a result, the pressure in the heat sink 12 decreases and the rotational resistance of the cooling fan 19 with motor decreases, so that the cooling fan 19 with motor can rotate at a higher speed and a higher cooling effect can be obtained. Become.

<Effect>
The thermal transfer printer of this embodiment includes a motor-equipped cooling fan 19 that is driven by a built-in motor and cools the heat sink 12, and the first and second drive gear trains 9 and 10 are equal to or greater than the maximum number of rotations of the motor-equipped cooling fan 19. Since the gear ratio is configured so that the auxiliary cooling fans 11a and 11b rotate, the motor-equipped cooling fan 19 can rotate at a higher speed with reduced rotational resistance, and a high cooling effect can be obtained. It becomes.

  1 paper transport motor, 2 belt, 3 paper transport roller drive gear, 4 pinch roller, 5 paper transport roller, 6 idle gear, 7 planetary gear, 8 print paper, 9 first drive gear train, 10 second drive gear train, DESCRIPTION OF SYMBOLS 11 Cooling fan, 11a, 11b Auxiliary cooling fan, 12 Heat sink, 13 Thermal head, 14 Ink ribbon, 15 Platen roller, 16 Lever gear, 17 Solenoid, 18 Spring, 19 Cooling fan with motor, 20a, 20b Auxiliary cooling fan drive gear, 21a, 21b Synchronous gear, 22 Synchronous shaft.

Claims (4)

A paper transport roller for applying a transport force to the print paper;
A paper transport motor for applying a rotational driving force to the paper transport roller;
A thermal head for thermally transferring ink to the print paper;
A heat sink attached integrally to the thermal head and dissipating the thermal head; and
A cooling fan for cooling the heat sink;
A driving force transmission mechanism that transmits a rotational driving force of the paper transport motor to the cooling fan;
Thermal transfer printer. The paper transport motor gives a bidirectional rotational driving force to the paper transport roller;
The driving force transmission mechanism is
A first drive gear train having one end engaged with the drive unit of the cooling fan;
A second drive gear train having one end meshed with the drive unit of the cooling fan and configured by an odd number of gears different from the first drive gear train;
A planet that receives the rotational driving force of the paper transport motor and selectively meshes with the other end of either the first drive gear train or the second drive gear train according to the rotational direction of the paper transport roller. With gear,
The thermal transfer printer according to claim 1. A paper transport roller driving gear that is provided integrally with the paper transport roller and transmits a rotational driving force received from the paper transport motor to the paper transport roller;
A lever gear disposed between the paper conveying roller driving gear and the planetary gear so as to be movable at a meshing position and a non-meshing position of both gears;
The thermal transfer printer according to claim 2. A motor-driven cooling fan that is driven by a built-in motor and cools the heat sink;
The first and second drive gear trains are configured to have a gear ratio so that the cooling fan rotates at a maximum rotational speed of the cooling fan with motor.
The thermal transfer printer according to claim 2 or 3.

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