JP3438432B2 - Thermal head support device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head supporting device provided in a thermal transfer printer.

[0002]

2. Description of the Related Art As a prior art thermal head supporting device, there is one as shown in FIG. 3 and FIG.
explain. In FIGS. 3 and 4, reference numeral 1 denotes a substantially rectangular parallelepiped thermal head, which includes a heat generating portion 1A and a heat sink 1B that dissipates the heat of the heat generating portion 1A. In addition, the front surface of the thermal head 1 has a protrusion 1C at the center.
Are formed. Reference numeral 2 denotes a head bracket formed by bending a metal plate into a substantially L shape. The mounting piece 2A is formed with a screw hole, and the supporting piece 2B is formed with a long groove hole 2C opening to the outside. This head bracket 2
The mounting piece 2A is mounted on the projecting portion 1C of the thermal head 1 with the screw 3, and the head shaft 4 is internally fitted and penetrates the long groove 2C of the supporting piece 2B. The head shaft 4 rotatably supports a head press bar 5, and both ends thereof are attached to a frame of a printer (not shown).

The head press bar 5 is a thermal head 1.
A top plate 5A having a plurality of openings 5B formed therein and side plates 5C, 5C, 5D, 5D extending from both edges of the top plate 5A toward the thermal head 1 are integrally formed. There is. This head press bar 5 is provided with each side plate 5
The mounting holes 5E and 5E formed at the tips of C and 5C are rotatably mounted by externally fitting the both ends of the head shaft 4, respectively. Further, the side plates 5D, 5D of the head press bar 5 are provided with grooves M, M at their tips. The head shaft 4 is formed with circumferential grooves 4A and 4B on both sides of the head bracket 2 in the axial direction which are fitted onto the head shaft 4. The respective circumferential grooves 4A and 4B are retaining rings 7 and 8 serving as a regulating member. Is externally fitted to hold the head bracket 2 from this axial direction. As a result, the head bracket 2 engages with the respective retaining rings 7 and 8 to restrict movement of the thermal head 1 in the axial direction of the head shaft 4.

Reference numeral 9 denotes a support member, which has a projection 9A and a recess 9B which is externally fitted to the shaft of the platen roller 10 and which is attached to the side surface of the thermal head 1. The protruding piece 9A of the support member 9 is inserted into the groove portions M of the head press bar 5. Reference numerals 15 and 15 are pressure contact springs, which are the upper plate 5 of the thermal head 1 and the head press bar 5.
The thermal head 1 is urged toward the platen roller 10 side by being interposed between the thermal head 1 and A.

In the thermal head supporting device thus constructed, in the initial state at the time of printing, the head press bar 5 is moved by a drive device (not shown) at a predetermined angle in the direction in which the head press bar 5 is separated from the thermal head 1 with the head shaft 4 as an axis. Is rotated. Thereby, the heat generating portion 1 of the thermal head 1
A is separated from the platen roller 10. In this state, the supply roller 16 of the printing paper 20 is rotated so that the printing paper 20 is color-coded into a plurality of ink ribbons 25.
At the same time, when it is conveyed between the platen roller 10 and the heat generating portion 1A of the thermal head 1, the driving device causes
The head press bar 5 rotates about the head shaft 4 in the direction of the thermal head 1 by a predetermined angle to compress the plurality of pressure contact springs 15 and 15 and rotate the platen roller 10 (rotate in the same direction as the supply roller 16). ) Do. As a result, when the printing paper 20 passes between the thermal head 1 and the platen roller 10, the pressure contact springs 15, 15 are pressed.
When the heat is applied to the plantain roller 10 with the pressing force P1 (spring force) of the ink, the electric current is supplied to the heat generating portion 1A of the thermal head 1 and the heat generating portion 1A generates heat, whereby the ink ribbon 2
The ink of No. 5 is melted and transferred to the printing paper 20. Then, by rotating the supply roller 16 and the platen roller 10 in the reverse / normal direction, the printing paper 20 is repeatedly reciprocated between the thermal head 1 and the platen roller 10, and printing of several colors is performed.

By the way, in the case of printing several colors by repeating the reciprocation of the printing paper between the thermal head 1 and the platen roller 10 as described above, the relationship between the head bracket 2 and the retaining rings 7 and 8 In this case, the horizontal displacement of the thermal head 1 in the axial direction of the head shaft 4 is prevented from occurring, and the color displacement after printing is reduced.

[0007]

However, in this prior art thermal head supporting device, if there is a slight gap between the head bracket and the retaining ring in the axial direction of the head shaft, the printing paper may be printed during printing. The thermal head is laterally offset by this gap. As a result, there is a problem in that the prints of the respective colors, which are printed back and forth between the thermal head and the platen roller, are displaced from each other, and the image quality of the prints on the print paper deteriorates.

At this time, if the gap between the head bracket and the retaining ring is brought close to zero, the above problem is considered to be solved, but the machining accuracy of each component becomes extremely severe, and it is necessary to make the gap zero. Not feasible.

The present invention has been made in order to solve this problem. By eliminating the movement of the thermal head in the axial direction of the shutter head, the misalignment of printing of each color is eliminated,
An object of the present invention is to provide a supporting device for a thermal head capable of improving the image quality of printing on printing paper.

[0010]

In order to solve the above problems, the thermal head supporting apparatus according to the present invention comprises:
In a shaft for pivotally supporting a thermal head for printing by moving an ink ribbon and a printing paper between a platen roller and an axial direction by sandwiching the thermal head from the axial direction of the shaft. A pair of regulating members for regulating the movement of the thermal head, a head press bar rotatably supported by the shaft so as to cover the thermal head, and a head press bar interposed between the thermal head and the head press bar. In a thermal head supporting device comprising a plurality of pressure contact springs for urging the thermal head toward the platen roller by a compression operation by rotating the head press bar, each of the pressure contact springs rotates the head press bar. And a pressing force for urging the thermal head toward the platen roller and a pressing force for urging the thermal head in the axial direction of the shaft. In which are arranged obliquely to generate. According to this, in printing, when the head press bar is rotated to compress the pressure contact springs, the pressure contact springs urge the thermal heads toward the platen roller and the thermal heads move in the same direction along the axis of the shaft. Since a pressing force that urges the thermal head is generated, the thermal head can be moved in the axial direction of the shaft by the pressing force so that the thermal head can be engaged so as to be pressed against the one regulating member. Even if there is a gap between them, it is possible to regulate the lateral displacement of the shank of the thermal head in the axial direction.

According to a second aspect, in addition to the first aspect,
The thermal head is reciprocally moved with respect to an ink ribbon, which is interposed between the platen roller and divided into a plurality of colors, to perform color printing on the printing paper. According to this, even if the printing paper reciprocates between the thermal head and the platen roller to print a plurality of colors, it is possible to eliminate the deviation of the printing of each color and improve the printing image quality of the printing paper. Becomes

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A thermal head supporting device according to an embodiment of the present invention will be described below with reference to the drawings. 1 is a rear view showing a thermal head supporting device according to an embodiment of the present invention, and FIG. 2 is a side view showing a thermal head supporting device according to an embodiment of the present invention. 1 and 2 in the embodiment of the present invention, the same reference numerals as those in FIGS. 3 and 4 of the prior art have the same configuration, and therefore the description thereof will be omitted.

In FIGS. 1 and 2, the thermal head 1
Pressure contact springs 1 interposed between the head press bar 5 and the head press bar 5.
Reference numerals 5 and 15 denote inclined surfaces 15 whose both end surfaces are parallel to each other and have a predetermined angle θ with respect to the axial direction of the head shaft 4.
A and 15B. And each pressure contact spring 15, 1
5 is a state in which they are tilted in the same direction with respect to the axial direction of the head shaft 4, and the inclined surfaces 15A and 15B are respectively provided with the heat sink 1B and the head press bar 5 of the thermal head 1.
The upper plate 5A is engaged with each other and is interposed between the thermal head 1 and the head press bar 5.

In the initial state at the time of printing, the head press bar 5 is rotated about the head shaft 4 by a predetermined angle in a direction away from the thermal head 1 by a driving device (not shown). As a result, the thermal head 1
The heat generating portion 1A is separated from the platen roller 7. In this state, the supply roller 16 of the printing paper 20 is rotated, and the printing paper 20 is conveyed together with the ink ribbon 25 between the platen roller 7 and the heat generating portion 1A of the thermal head 1. The head press bar 5 rotates about the head shaft 4 in the direction of the thermal head 1 by a predetermined angle to compress the plurality of pressure contact springs 15, 15 and rotate the platen roller 10 (supply roller 1).
Rotate in the same direction as 6. ) Do.

Then, the respective pressure contact springs 15 and 1 are slantly interposed between the thermal head 1 and the head press bar 5.
5, the spring force generates a partial pressure composed of a pressing force P2 for urging the thermal head 1 toward the platen roller 10 and a pressing force P3 for urging the thermal head 1 in the same direction as the axis of the head shaft 4, Printing paper 20 is thermal head 1
When passing between the platen roller 10 and the platen roller 10, the resultant force F1 of the pressing force P2 of the pressure contact springs 15 is brought into contact with the plantain roller 10, and the thermal head 1 is caused by the resultant force F2 of the pressing force P3. It is moved along with the support piece 2B of the head bracket 2 in one axial direction of the head shaft 4 while absorbing the gap existing between the support piece 2B and the retaining ring 8, and finally the support piece 2B is moved. It engages so that it may be pressed down to 8.

As a result, the movement of the thermal head 1 in the axial direction of the head shaft 4, that is, the lateral displacement of the thermal head 1 is regulated by the engagement of the support piece 2B and the retaining ring 8, and the thermal head 1 is regulated. By supplying an electric current to the heat generating portion 1A of the ink, the ink of the ink ribbon 25 is melted and transferred to the printing paper 20, and by rotating the supply roller 16 and the platen roller 10 in the reverse / normal direction, the printing paper 20
Is repeatedly reciprocated between the thermal head 1 and the platen roller 10, and printing of several colors can be performed.

[0017]

As described above, according to the thermal head supporting apparatus of the present invention, in printing, when the head press bar is rotated to compress the respective pressure contact springs, the thermal contact is performed on each pressure contact spring. Along with the pressing force that urges the head against the platen roller, a pressing force that urges the thermal head in the same direction as the axis of the shaft is generated, and this pressing force moves the thermal head in the axial direction of the shaft to create one regulating member. Even if there is a gap between the regulating member and the thermal head, the lateral displacement of the shank of the thermal head in the axial direction can be regulated by engaging so as to press the shank. As a result, even when the printing paper reciprocates between the thermal head and the platen roller to perform printing of several colors, it is possible to eliminate the printing misalignment of each color and improve the printing image quality of the printing paper.

In the second aspect, in addition to the effect of the first aspect,
Even when the printing paper reciprocates between the thermal head and the platen roller to perform printing of a plurality of colors, it is possible to eliminate the printing deviation of each color and improve the printing image quality of the printing paper.

[Brief description of drawings]

FIG. 1 is a rear view showing the configuration of a thermal head support device according to an embodiment of the present invention.

FIG. 2 is a side view showing the configuration of a thermal head support device according to an embodiment of the present invention.

FIG. 3 is a perspective view showing a configuration of a conventional thermal head supporting device.

FIG. 4 is a schematic side view showing a configuration of a conventional thermal head supporting device.

[Explanation of symbols] 1 thermal head 4 head shaft 7, 8 Retaining ring (restriction member) 10 Platen roller 15, 15 pressure contact spring 20 printing paper

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Claims (2)

(57) [Claims] 1. A shaft for rotatably supporting a thermal head for printing by moving an ink ribbon and printing paper between a platen roller and the thermal head in the axial direction of the shaft. A pair of restricting members for restricting axial movement, a head press bar rotatably supported by the shaft so as to cover the thermal head, and an interposing member between the thermal head and the head press bar. In a thermal head supporting device comprising a plurality of pressure contact springs for urging the thermal head toward the platen roller by a compression operation by rotating the head press bar, each of the pressure contact springs includes: By the compression operation by the rotation, the pressing force that urges the thermal head toward the platen roller and the pressing force that urges the thermal head in the same direction as the axis of the shaft. Supporting device of a thermal head is characterized in that it is arranged obliquely so as to generate a force. 2. The thermal head is configured to reciprocate with respect to an ink ribbon, which is interposed between the platen roller and color-coded into a plurality of colors, and reciprocates to print the printing paper in color. The thermal head support device according to claim 1.