JP2905632B2 - 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 thermal printer.

[0002]

2. Description of the Related Art As shown in FIG. 6, a thermal printer passes a thermal paper 104 between a platen 101 and a line thermal head 102, and
By thermally driving the heating elements 103 aligned on one straight line, only the heat-generating elements 103 that generate heat are subjected to thermal coloring to perform thermal printing.

In this thermal printer, a thermal paper 10 is placed between a platen 101 and a line thermal head 102.
Conventionally, as an opening / closing mechanism for passing the ink ribbon 3 or the like, the rotating shaft 105 of the line thermal head 102 is fixed to the rotating shaft of the platen 101 as shown in FIG. There is a method in which the line thermal head 102 is pressed against the platen 101 as shown in FIG. In the method shown in FIG. 8, the line thermal head 102 is fixed to the head holding plate 106, and performs a seesaw motion left and right around a fulcrum shaft 107 provided at the upper central position of the head holding plate 106, thereby moving the line thermal head 102 to the platen. The groove 108 provided on the right and left sides of the head holding plate 106 fits into the shaft portion of the platen 101 to perform positioning in the front-rear direction.

[0004]

However, the line thermal head 1 is rotated with respect to the rotation axis of the platen 101 shown in FIG.
02 is fixed to the platen 101.
In order to obtain the parallel accuracy and the positional accuracy of the heating element line of the thermal head 102 and the rotational axis 1 of the thermal head 102,
05 needs to be located near the platen axis,
Therefore, the line thermal head 102 is
There is a problem that the space between the line thermal head 102 and the platen 101 when it is separated from the printer is narrow, and it is not easy to pass paper, an ink ribbon, and the like between them.

A line thermal head 10 shown in FIG.
In the method in which the line thermal head 2 follows the platen 101 and presses the line thermal head 102, the line thermal head 102 can be largely opened when the line thermal head 102 is separated from the platen 101.
There is a problem that the mechanism for moving the seesaw 02 right and left with high parallel accuracy and position accuracy is complicated.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a thermal printer that can greatly open a space between a line thermal head and a platen, and can press the line thermal head against the platen with a simple structure. The purpose is to:

[0007]

According to the present invention, in order to achieve the above object, a platen is disposed on a lower chassis, and a line thermal head is disposed on an upper chassis which can be opened and closed with respect to the lower chassis. At the rear, fix the axis parallel to the direction in which the heating elements are arranged, and attach this axis to the upper chassis with freedom, and attach the line thermal head to the lower chassis between the front of the line thermal head and the upper chassis. The biasing means for biasing is disposed on both the left and right sides, and a guide is provided on the lower chassis to regulate the shaft only in the front-rear direction when the upper chassis is closed.

[0008]

According to the present invention, by disposing the open / close fulcrum axis of the lower chassis and the upper chassis and the platen axis apart from each other, the line thermal head can be largely opened when the line thermal head is separated from the platen. In addition, when the line thermal head and the platen are pressed against each other, the shaft is fitted into the guide to position the line thermal head in the front-rear direction. The line thermal head is urged toward the platen and moves freely in the height direction, so that the line thermal head follows the platen and is pressed against the platen, applying a uniform pressing force to all the heating elements in the heating element line of the thermal head. Can be given.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the thermal printer according to the present invention will be described below with reference to FIGS.

1 and 2, a platen 2 and a motor 3 for driving the platen 2 are attached to a lower chassis 1. Further, guide grooves 4 are provided on both side plates of the lower chassis 1 in the vicinity of the bearing holes of the platen 2.

The line thermal head 5 is fixed to a thermal head holding plate 7 having a shaft 6, and the shaft 6 is fitted into a hole 9 larger than the diameter of the shaft 6 on both sides of the upper chassis 8, whereby the upper thermal chassis 5 is rotated. 8 with a degree of freedom.

Coil springs 10 are interposed between the front upper surface of the thermal head holding plate 7 and the lower surface of the upper chassis 8 to bias the thermal head holding plate 7 in the direction of arrow A in FIG. The pin 11 fixed to the upper chassis 8 stops a certain amount of movement due to the bias of the thermal head holding plate 7.

The upper chassis 8 and the lower chassis 1 are opened and closed about a fulcrum shaft 12 as a fulcrum. When the upper chassis 8 is closed to the lower chassis 1, the lock claws 13 attached to the upper chassis 8 are hooked on the pins 14 of the lower chassis 1, and the upper chassis 8 is locked to the lower chassis 1. By turning the release lever 15 connected to the lock claw 13,
By detaching the upper chassis 8 from the pins 14, the upper chassis 8 can be opened from the lower chassis 1.

In such a configuration, the upper chassis 8
Is opened from the lower chassis 1 and the thermal paper 16 is set, and then the upper chassis 8 is closed to the lower chassis 1. Then, first, as shown in FIG. 3, the shaft 6 is fitted into the guide grooves 4 of both side plates of the lower chassis 1, and the position of the line thermal head 5 in the front-rear direction is achieved. Next, as shown in FIG. 4, the line thermal head 5 contacts the platen 2 with the thermal paper 16 sandwiched therebetween. Further, the upper chassis 8 is closed, and the lock claws 13 are hooked on the pins 14 in the state of FIG.
The upper chassis 8 is fixed to the lower chassis 1.

At this time, as shown in FIG.
The spring force of 0 (arrow B) is distributed to the pressure contact force (arrow c) between the line thermal head 5 and the platen 2 and the contact force (arrow d) between the left and right holes 9 and the shaft 6. The contact force between the shaft 6 and the shaft 6 is slightly smaller than the contact force between the line thermal head 5 and the platen 2. Therefore, the line thermal head 5 has the same load on both sides due to the biasing force of the left and right coil springs 10.
Presses the platen 2 and the line thermal head 5 moves freely in the height direction, so that the line thermal head 5 follows the platen 2 and comes into pressure contact therewith.

In this state, the motor 3 is driven to
6 is fed, and the heating element of the line thermal head 5 is thermally driven in synchronization with the feeding of the thermal paper 16, whereby the thermal paper 16 is thermally colored and printed.

[0017]

According to the thermal printer of the present invention, as described above, by disposing the open / close fulcrum shafts of the lower chassis and the upper chassis and the platen shaft apart from each other, the distance between the line thermal head and the platen can be reduced. When the line thermal head and the platen are pressed against each other, the shaft fits into the guide to align the line thermal head in the front-rear direction. The line thermal head is evenly biased toward the platen and the line thermal head moves freely in the height direction, so that the line thermal head follows the platen and is pressed against the platen. The effect that a pressing force can be applied is obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a thermal printer according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of the embodiment.

FIG. 3 is a longitudinal sectional view similar to FIG. 2, showing an intermediate state when the upper chassis is closed in the embodiment.

FIG. 4 is a longitudinal sectional view similar to FIG. 2, showing a state immediately before closing an upper chassis in the embodiment.

FIG. 5 is a longitudinal sectional view similar to FIG. 2, showing a state in which an upper chassis is closed in the embodiment.

FIG. 6 is a conceptual diagram of thermal printing.

FIG. 7 is a perspective view of a first conventional example.

FIG. 8 is a perspective view of a second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower chassis 2 Platen 4 Guide groove 5 Line thermal head 6 Axis 8 Upper chassis 9 Hole 10 Coil spring

──────────────────────────────────────────────────の Continued on the front page (72) Manabu Eguchi 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) Naoki Hatada 1006 Kadoma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co. In-company (56) References JP-A-60-1884867 (JP, A) JP-A-4-69156 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41J 25/312 B41J 25/304 B41J 25/316

Claims (1)

(57) [Claims] 1. A platen is arranged on a lower chassis, a line thermal head is arranged on an upper chassis which can be opened and closed with respect to the lower chassis, and an axis parallel to a direction in which the heating elements are arranged is fixed to a rear portion of the line thermal head. This shaft is attached to the upper chassis with a degree of freedom, and biasing means for biasing the line thermal head toward the lower chassis are arranged between the front of the line thermal head and the upper chassis on both the left and right sides. A thermal printer having a guide for regulating the shaft only in the front-rear direction when the chassis is closed.