JPH04216084A - Thermal printer - Google Patents

Abstract

PURPOSE:To favorably bring heating elements on a thermal head into close contact with the peripheral surface of a platen roller by a method wherein support pins are displaceably engaged with slots, and the thermal head pressed against the platen roller by the resilient force of leaf springs is supported so as to displace in this pressing direction. CONSTITUTION:Slots 11 of a support board 10 of a displacing mechanism 12 are so formed as to be long in a direction in which leaf springs 8 press a thermal head 2 against a platen roller 7. The support board 10 with the thermal head 2 mounted is pivotably and displaceably supported by support pins 5 displaceably engaged with the slots 11. The thermal head 2 pressed against the peripheral surface of the platen roller 7 by the resilient force of the leaf springs 8 is supported by the displacing mechanism 12 so as to be displaced only in the pressing direction. Therefore, heating elements on the thermal head 2 and the peripheral surface of the platen roller 7 come into close contact with each other, whereby a printing quality is improved.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer equipped with a thermal head in which heating elements are arranged in a line.

0002

2. Description of the Related Art A conventional example of a thermal printer will be explained with reference to FIG. First, in this thermal printer 1, a thermal head 2 in which heating elements (not shown) are arranged in a line near one edge is attached to a support plate 3, which is a support member. A support pin 5, which is an engagement member attached to a body frame (not shown), is fitted into a round hole 4 formed at the end of the thermal head 2, thereby rotatably supporting the thermal head 2. A support mechanism 6 is formed. The thermal head 2 rotatably supported by the support mechanism 6 faces the rotatable platen roller 7 at the position of the heating element.
A biasing mechanism for pressing the thermal head 2 is provided on the circumferential surface of the platen roller 7 using a leaf spring 8 .

With this configuration, in this thermal printer 1, the thermal head 2 rotatably supported by the support mechanism 6 is pressed against the circumferential surface of the platen roller 7 by the elastic force of the leaf spring 8. Image printing is performed by driving the heating element of the thermal head 2 to generate heat and conveying thermal paper (not shown) or the like by rotation of the platen roller 7.

[0004] In this thermal printer 1, for example, when handling jams such as paper jams, etc.
After the pressing force of the leaf spring 8 is released, the thermal head 2 is rotated according to the support of the support mechanism 6 and separated from the platen roller 7.

[0005]

[Problems to be Solved by the Invention] In the above-described thermal printer 1, in order to bring the heating element of the thermal head 2, which is rotatably supported by the support mechanism 6, into close contact with the circumferential surface of the platen roller 7, the elasticity of the leaf spring 8 is The thermal head 2 is pressed against the platen roller 7 by the generated force.

However, the support mechanism 6 of the thermal printer 1 described above has a structure in which the support plate 3 is rotatably supported by the support pin 5 fitted in the round hole 4. The direction of movement of the thermal head 2 attached to the support mechanism 6 is limited to the direction of rotation of the support mechanism 6. Therefore, for example, if there is a relative error in the axial direction between the support mechanism 6 and the platen roller 7, the heating element of the thermal head 2 and the circumferential surface of the platen roller 7 will not be in good contact with each other. As a result, the print quality of the thermal printer 1 will deteriorate.

[0007] As a means to solve such problems,
It is conceivable to manufacture each part with extremely high precision so that the thermal head 2 and the platen roller 7 can be brought into good contact with each other, but this would reduce the productivity of the thermal printer 1 and is not practical.

[0008]

[Means for Solving the Problems] A thermal head in which heating elements are arranged in a line is provided, a platen roller whose peripheral surface faces the heating element of the thermal head is rotatably supported, and the platen roller is rotatably supported. A support mechanism is provided to rotatably support the thermal head in a direction in which the heating element moves away from the circumferential surface, and a biasing mechanism is provided to press the rotatably supported thermal head against the circumferential surface of the platen roller. In a thermal printer equipped with a thermal printer, the thermal head is rotatably supported and attached by a support member in which an elongated hole is formed in the pressing direction of the biasing mechanism, and an engagement member that displaceably engages with the elongate hole. A displacement mechanism is formed within the support mechanism to support the displacement mechanism so as to be freely displaceable in the pressing direction of the force mechanism.

[0009]

[Operation] The thermal head is rotatably supported by a support member in which an elongated hole is formed in the pressing direction of the biasing mechanism, and an engagement member that displaceably engages with the long hole, while also pressing the biasing mechanism. By forming a displacement mechanism within the support mechanism that supports the thermal head so that it can be displaced in the pressing direction, the thermal head is pressed against the circumferential surface of the platen roller while being supported so that it can be displaced only in the pressing direction. The heating element of the head and the circumferential surface of the platen roller can be brought into good contact with each other.

0010

[Embodiment] An embodiment of the present invention will be explained based on FIGS. 1 and 2. As illustrated in FIG. 1, this thermal printer 9 has a long hole 11 formed at the end of a support plate 10, which is a support member to which the thermal head 2 is attached, and an engagement member is inserted into this long hole 11. A displacement mechanism 12 that also serves as a support mechanism is formed by displaceably engaging a certain support pin 5 . Here, the elongated hole 11 of the support plate 10 of the displacement mechanism 12 is formed to be elongated in the direction in which the plate spring 8 presses the thermal head 2 against the platen roller 7 . As illustrated in FIG. 2, in this thermal printer 9, a label sheet 14 wound into a roll is rotatably stored in a main body housing 13, and this label sheet 13 is connected to a thermal head 2 and a platen. It is guided between the roller 7 and the roller 7. Note that the other structure is the same as that of the thermal printer 1 described above.

With this configuration, this thermal printer 9 performs printing and jam processing in the same manner as the thermal printer 1 described above.

Here, in the displacement mechanism 12 of this thermal printer 9, the support plate 1 to which the thermal head 2 is attached is
0 is rotatably supported by a support pin 5 which is displaceably engaged with the elongated hole 11 and is also displaceably supported. Therefore, in this thermal printer 9, the thermal head 2 pressed against the platen roller 7 by the elastic force of the leaf spring 8 is supported so as to be freely displaceable in this pressing direction.
For example, even if there is a relative error in the axial direction between the displacement mechanism 12 and the platen roller 7, the thermal head 2
The heating element is in close contact with the circumferential surface of the platen roller 7. Moreover, in the displacement mechanism 12 of this thermal printer 9, the elongated hole 11 of the support plate 10 is connected to the thermal head 2.
Since the support pin 5 is fixedly engaged in the direction perpendicular to the pressing direction, the thermal head 2 can be accurately supported on the circumferential surface of the platen roller 7 at the position of the linear heating element. become.

That is, in this thermal printer 9, the thermal head 2, which is pressed against the peripheral surface of the platen roller 7 by the elastic force of the leaf spring 8, is supported by the displacement mechanism 12 so as to be freely displaceable only in the pressing direction. The heating element of the thermal head 2 and the circumferential surface of the platen roller 7 are brought into close contact with each other, resulting in improved printing quality.

In this embodiment, a thermal printer 9 is provided, in which a support plate 10, which is a support member in which a long hole 11 is formed, is attached to a thermal head 2, and a support pin 5, which is an engagement member, is attached to a main body frame, etc. Although the present invention is not limited to the above structure, for example, the elongated hole 11 may be formed in the main body frame, which is a support member, to which the support pin 5, which is an engagement member, is attached to the thermal head 2. A thermal printer (not shown) can also be used.

[0015]

Effects of the Invention As described above, the present invention provides a thermal head in which heating elements are arranged in a line, and rotatably supports a platen roller whose peripheral surface faces the heating element of the thermal head. A support mechanism is provided to rotatably support the thermal head in a direction in which the heating element moves away from the circumferential surface of the platen roller, and this support mechanism presses the rotatably supported thermal head against the circumferential surface of the platen roller. In a thermal printer equipped with a biasing mechanism, the thermal head is pivotably rotated by a support member in which a long and narrow hole is formed in the pressing direction of the biasing mechanism, and an engagement member that engages with the long hole in a freely displaceable manner. By forming a displacement mechanism within the support mechanism that supports the thermal head and displaces it freely in the pressing direction of the biasing mechanism, the thermal head moves around the platen roller while being supported so that it can be displaced only in the pressing direction. Since it is pressed against the surface, the heating element of the thermal head and the circumferential surface of the platen roller can be brought into good contact with each other, which has the effect of contributing to improving the printing quality of the thermal printer.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a longitudinal side view.

FIG. 3 is a perspective view showing a conventional example.

[Explanation of symbols]

2 Thermal head 5
Support member 7 Platen roller 8
Biasing mechanism 9 Thermal printer 10
Support member 11 long hole

Claims (1)

[Claims] 1. A thermal head in which heat generating elements are arranged in a line is provided, a platen roller whose circumferential surface faces the heat generating elements of the thermal head is rotatably supported, and the A support mechanism is provided that rotatably supports the thermal head in a direction in which the heating elements are separated, and a biasing mechanism that presses the thermal head rotatably supported by the support mechanism against the circumferential surface of the platen roller. In the thermal printer, the thermal head is rotatably supported by a support member having an elongated hole formed in the pressing direction of the urging mechanism and an engaging member displaceably engaged with the elongate hole. A thermal printer characterized in that a displacement mechanism is formed within the support mechanism to support the biasing mechanism so as to be displaceable in the pressing direction of the biasing mechanism.