JPH0550703A - Thermal head device - Google Patents

Abstract

PURPOSE:To miniaturize the whole of a printer by miniaturizing an upper mechanism while making a thermal head largely separable from a platen roller and simplify not only the opening and closing operation of the upper mechanism but also the replacement or maintenance of an ink sheet. CONSTITUTION:A head plate 29 is arranged under a head part 27 and connected to both end parts of the head part 27 in the lateral direction thereof through a latch 28 in a freely detachable manner and the spring 33 bringing a thermal head 26 into contact with a platen roller 1 under pressure is provided between the central part of the head plate 29 in the lateral direction thereof and a printer main body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal head device for pressing a thermal head against a platen roller.

[0002]

2. Description of the Related Art FIG. 5 is a side view showing a conventional thermal head device similar to that disclosed in Japanese Patent Laid-Open No. 2-2021. In the figure, 1 is a platen roller, 2
Is an arm rotatably provided around the fulcrum 3 in the printer body, 4 is a heat sink attached to the tip of the arm 2, and 5 is a thermal head attached to the heat sink 4. 5 is
It is adapted to come into contact with and separate from the platen roller 1 by the rotation of the arm 2.

Reference numeral 6 denotes a head pressing member rotatably provided on the printer main body about a fulcrum 3, 7 is provided between the head pressing member 6 and the arm 2, and the thermal head 5 is pressed against the platen roller 1. The first spring 8 is a latch attached to the head pressing member 6 so as to be rotatable about the latch shaft 8a, and 9 is a plate shaft 9a on the printer body.
The head contacting / separating plate is rotatably provided around the center of the head. A latch 8 is detachably engaged with the tip of the head contacting / separating plate 9. Reference numeral 10 is a second spring for urging the latch 8 in a direction to engage with the head contact / separation plate 9,
Reference numeral 11 denotes a cam that is in contact with the head contact / separation plate 9. The rotation of the cam 11 causes the head contact / separation plate 9 to reciprocally rotate, and the thermal head 5 is contacted and separated from the platen roller 1.

In the conventional thermal head device constructed as described above, the latch 8 is opposed to the second spring 10.
Is rotated counterclockwise in the figure, the latch 8 is removed from the head contact / separation plate 9. As a result, the entire upper mechanism to which the thermal head 5 is attached can be opened by rotating around the fulcrum 3. Then, with the upper mechanism opened in this manner, ink sheet replacement, maintenance work, and the like are performed.

However, in such a thermal head device, since the upper mechanism becomes large and heavy, the entire printer becomes large and the workability of opening and closing the upper mechanism is deteriorated.

On the other hand, FIG. 6 shows, for example, JP-A-57-57.
It is a basic block diagram which shows the other conventional thermal head apparatus shown by 142142 gazette. In the figure, the thermal head 5 includes a spring mounting portion 12 provided below the arm 2.
The platen roller 1 is pressed against the platen roller 1 by the third spring 13 between the arm 2 and the arm 2. Further, the contact / separation of the thermal head 5 with respect to the platen roller 1 is performed by a solenoid 14 connected to the arm 2.

In the conventional thermal head device having such a structure, since the spring mounting portion 12 and the third spring 13 are arranged below the arm 2, the upper mechanism can be reduced to some extent.

[0008]

Among the conventional thermal head devices constructed as described above, the one shown in FIG. 5 has a large upper mechanism as described above, so that the entire printer is large in the height direction. There is a problem in that the workability of opening and closing the upper mechanism decreases as the shape is reduced. On the other hand, FIG.
In the above, since the upper mechanism, that is, the arm 2 cannot be separated from the third spring 13 and the solenoid 14, the upper mechanism cannot be widely opened, and the ink sheet replacement and maintenance by opening the upper mechanism are not possible. There was a problem that it was difficult.

The present invention has been made to solve the above-mentioned problems, and it is possible to separate the thermal head largely from the platen roller, and at the same time, to provide an upper mechanism that separates the thermal head from the platen roller. (EN) A thermal head device that can be downsized, which makes it possible to downsize the entire printer, simplify the opening / closing operation of the upper mechanism, and easily replace and maintain the ink sheet. With the goal.

[0010]

SUMMARY OF THE INVENTION In a thermal head device according to the present invention, a head plate is arranged below a head portion, and both ends of the head portion in the width direction are detachably connected via latches to connect the thermal head. A spring that is pressed against the platen roller is provided between the central portion of the head plate in the width direction and the printer body.

[0011]

According to the present invention, the head plate is arranged below the head portion, and the head plate and the head portion are detachably connected by the latch so that the thermal head can be widely separated from the platen roller. Miniaturize the upper mechanism that separates from the platen roller.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a thermal printer according to an embodiment of the present invention. The same or corresponding parts as those in FIGS. In the figure, 21 is a printer main body, 22 is a paper cassette detachably attached to the printer main body 21, and 23 is an ink sheet replaceably provided in the printer main body 21.

Reference numeral 24 is an arm rotatably provided on the printer main body 21 about a fulcrum 25, and 26 is a thermal head provided at the tip of the arm 24. It moves toward and away from the platen roller 1. Reference numeral 27 is a head portion including an arm 24 and a thermal head 26.

FIG. 2 is an enlarged view of the configuration of the thermal head device of FIG. 1, FIG. 3 is a perspective view of an essential part of FIG. 2, and FIG. 4 is a front view of FIG. In the figure, 28 is a latch mounted on both ends of the thermal head 26 in the width direction so as to be rotatable around a latch shaft 26a, and 29 is a head plate provided below the head portion 27. 29 is
As shown in FIG. 3, first to third mounting holes 30a to 30c provided in the head plate mounting portion 30 of the printer body 21.
The printer body 21 is mounted by inserting the first to third mounting protrusions 29a to 29c into the printer main body 21. That is, the fulcrum of the head plate 29 has a so-called gimbal structure. Further, engaging projections 29d with which the latch 28 is engaged are provided at both ends of the head plate 29 in the width direction. Reference numeral 31 is a latch spring for urging the latch 28 in the direction of engaging the engagement protrusion 29d, and 32 is a stopper for restricting the rotation of the latch 28.

Numeral 33 is a spring provided between the central portion of the head plate 29 in the width direction and the printer main body 21, and this spring 33 connects the thermal head 26 to the platen roller 1 via the head plate 29 and the latch 28. Press against. Reference numeral 34 is two cam followers rotatably attached to the head plate 29, and 35 is a cam that comes into contact with the cam follower 34 and moves the head plate 29 up and down.
As shown in FIG. 3, the thermal head 26 is brought into contact with and separated from the platen roller 1 by being rotated by the motor 36 via the pinion 37 and the gear 38.

In the thermal head device constructed as described above, the latch 28 can be removed from the head plate 29 by rotating the latch 28 counterclockwise in FIG. 2 against the latch spring 31. .. As a result, the head portion 27 is rotated around the fulcrum 25, and the thermal head 26
Can be widely separated from the platen roller 1. Therefore, replacement and maintenance work of the ink sheet 23 can be easily performed by opening the head portion 27.

Further, since the head plate 29 and the spring 33, which are conventionally located above the head portion 27, are disposed below the head portion 27, which was a wasted space in the past, to form a lower mechanism, the upper mechanism is downsized. As a result, the entire printer is downsized in the height direction. Further, since the head plate 29 made of an iron plate serves as a lower mechanism and the head portion 27 is usually made of aluminum die-cast, the upper mechanism including the head portion 27 and the latch 28 is lightweight, and therefore the upper mechanism It is easy to open and close. Further, since the fulcrum of the head plate 29 has a gimbal structure and only one spring 33 is provided in the central portion in the width direction of the head plate 29, the contact pressure of the thermal head 26 to the platen roller 1 is in the width direction. Be uniform.

Although the cam 35 is used as a means for bringing the thermal head 26 into and out of contact with the platen roller 1 in the above embodiment, the invention is not limited to this. Further, although the latch 28 is attached to the thermal head 26 in the above-described embodiment, it may be attached to other portions of the head portion 27 or the head plate 29 side.

[0019]

As described above, according to the thermal head device of the present invention, the head plate is arranged below the head portion, and both ends of the head portion in the width direction are detachably connected via the latches. Since a spring for pressing the platen roller against the platen roller is provided between the center of the head plate in the width direction and the printer body, the thermal head can be widely separated from the platen roller and the upper mechanism that separates the thermal head from the platen roller. The size of the printer can be reduced, which allows the size of the entire printer to be reduced and the opening and closing of the upper mechanism can be simplified.
Moreover, it is possible to easily replace and maintain the ink sheet.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a thermal printer according to an embodiment of the present invention.

FIG. 2 is an enlarged configuration diagram showing the thermal head device of FIG.

FIG. 3 is a perspective view of a main part of FIG.

FIG. 4 is a front view of FIG.

FIG. 5 is a side view showing an example of a conventional thermal head device.

FIG. 6 is a basic configuration diagram showing another conventional example.

[Explanation of symbols]

 1 Platen roller 21 Printer body 24 Arm 26 Thermal head 27 Head 28 Latch 29 Head plate 33 Spring

Front Page Continuation (72) Inventor Tomoyuki Matsumoto 1-8 Midoricho, Fukuyama City Mitsubishi Electric Corporation Fukuyama Works

Claims (1)

[Claims] 1. A head portion having an arm rotatably provided on a printer main body and a thermal head provided at a tip end portion of the arm and contacting and separating from a platen roller by the rotation of the arm. A head plate provided below the head portion and detachably connected to both end portions in the width direction of the head portion via latches, and between a center portion in the width direction of the head plate and the printer body. And a spring for pressing the thermal head into pressure contact with the platen roller via the head plate and the latch.