JP2954103B2 - Thermal head pressing 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 pressing device in a printer having a line type thermal head for printing by a thermal printing system or a thermal transfer printing system.

[0002]

2. Description of the Related Art As shown in FIGS. 3 and 4, a conventional thermal head pressing device is provided with a line type thermal head 4 on a gantry 1 side facing a platen 3 of a printer. A convenient structure for attaching and detaching the head 4 has been devised.

[0003] In FIG. 3 and FIG. 4, the thermal head 4 is mounted on a head base 22, is positioned at the center of the print width of the thermal head 4 (sub scanning direction), and is located in front of and behind the head base 22. The head unit 24 is formed by providing the pins 19 and 20 and the spring support pins 18 on the left and right sides thereof. The compression coil spring 8 fitted on the spring support pins 18 is attached to the head base 22 and the holder on the gantry side. 17 so that it is held on the gantry 1.

[0004] A head piece 21 having a hole is interposed between a head portion formed at the lower end of the pins 19 and 20 and a horizontal support portion of the holder 17 by horizontal movement, and is fixed to the holder 17 with screws 10. By doing so, the level of the thermal head 4 on the gantry 1 is secured. For this reason, by rotating the lever 2 pivotally supported by the gantry 1, the platen 3 can be pressed against the thermal head 4, and the thermal head 4, together with other components, is formed as a unit (assembly). Can be installed and removed.

In this case, the hole of the head piece 21 has an irregular shape such as a key shape, and matches the hole formed in the horizontal support portion of the holder 17 before the horizontal movement. It is designed to pass through the head, and after horizontal movement, engage and hold the head at the edge of the hole,
Prevents it from falling upward. With such a configuration, the coil spring 8 elastically holds the thermal head 4 upward on the holder 17.

When the thermal head 4 is attached and detached (see FIG. 3), the lever 2 is pivoted upward to open the thermal head 4 when the thermal head 4 is attached. The unit is lowered in the direction of arrow G, and the pins 19 and 20 are passed through the holes as shown in FIG.
The thermal head 4 is fixed to the gantry 1 by engaging the head with the base piece 21. In such a state, at the time of printing, a printing medium (not shown) is passed over the thermal head 4, and the platen 3 is pressed onto the thermal head 4. When removing the thermal head 4, disassemble the parts in the reverse order to the above.
In particular, components on the gantry side such as the coil spring 8 and the base piece 21 are also disassembled.

[0007]

The first problem here is that, in the prior art, the mounting portion of the thermal head and the mechanical portion on the gantry side are configured as one unit, so that the thermal head When the unit is replaced for each unit, parts constituting the pressing mechanism such as the coil spring 8 and parts holding the coil spring 8 must be disassembled at the same time.

A second problem is that, in the prior art, when the position of the platen 3 is slightly changed, the thermal head 4 does not completely follow, and the thermal head and the platen do not adhere to each other over the printing width. Since there is a possibility that the thermal head and the platen may hit each other, it is impossible to obtain a uniform pressing of the print width.

The present invention has been made on the basis of the above circumstances, and makes it easy to attach and detach the thermal head of the printing mechanism, and to obtain a uniform pressing force over the printing width (sub scanning direction). The purpose of the present invention is to provide a thermal head pressing device configured as described above.

[0010]

Therefore, in the present invention,
In a printer equipped with a line-type thermal head for printing by the thermal printing method or the thermal transfer printing method, the thermal head facing the platen is a sub-frame that is pivotally supported by the frame in the middle of the printing width (sub-scanning direction). In addition, it is rotatably supported around an axis extending in the main scanning direction, and is supported upward by a pair of left and right elastic mechanisms provided on a gantry.

In this case, the sub-table is pivotally supported about an axis parallel to the sub-scanning direction, and the thermal head is moved right and left of the sub-table by the elastic mechanism with respect to the platen. It is preferable that the contact is made toward the printing width. Preferably, the elastic holding mechanism is a compression coil spring, and the sub-mount is screwed to the mount at its free end.

Therefore, the mounting portion of the thermal head and the pressing mechanism can be separated as a unit, and only the former can be disassembled from the stand without disassembling the entire printing mechanism. Also, when the positional relationship of the thermal head with respect to the platen (the hit with respect to the print width) is tilted, the thermal head rotates around the rotation fulcrum and follows the tilt of the platen. Over the printing width (sub-scanning direction)
An even pressing force can be obtained.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an example in which the pressing device of the present invention is applied to a thermal printer using roll paper. A procedure for attaching and detaching the thermal head 4 will be described below. FIG. 2 is for explaining the operation at the time of setting the thermal head.

The thermal head 4 for performing printing includes:
The head base 5 is attached to the head base 5 with fastening parts such as screws. The head base 5 has a bent portion perpendicular to the rear portion and the front portion. The bent portion has the same line (main scanning direction) in the front-rear direction, and is located at the center of the print width length. Pivot pins 11 and 12 that rotate around are provided. A head unit 23 (head mounting portion) for the thermal head 4 is configured including these components. Further, the front end of the pin 12 has an E for connecting the head unit 23 and a pressing mechanism 25 described later.
A groove is formed so that a fastening component such as the ring 13 can be attached.

Next, the above-described pressing mechanism 25 will be described.
The spring (compression coil spring) 8 is interposed between the upper holder (sub-frame) 6 and the lower holder 7 of the frame 1, and the upper holder 6 and the lower holder 7 are
Both are rotatable about a shaft 15 extending in the sub-scanning direction (perpendicular to the main scanning direction) as a rotation support axis. On the bracket 9 attached to the gantry 1, the lower part of the lower holder 7 is It is supported and fixed by fastening parts such as screws 10.

For this reason, the lower holder 7 is held at a fixed position on the gantry 1 and the upper holder 6 is
Lever 2 that is pushed upward by the
When the thermal head 4 is opened by rotating about a shaft pivotally supported on the gantry 1, a part of the lower holder 7 is engaged with a stopper 16 on a part of the gantry 1.・ It is retained.

In this state, when the upper holder 6 is pressed downward by rotating the lever 2 and lowering the platen 3 , the spring 8 is displaced, and the upward pressing force is reduced. Occur. Further, the bent portion of the upper holder 6, so that the pin 11, 12 of the head unit 2 3 side enters, since the concentric holes are drilled, the pin 11, the tip of the pin 12 is passed through the head unit Can be attached.

Moreover, the thermal head 4 has the pins 11
Since it is possible to turn left and right with the rotation shaft 12 as a rotation shaft, the pins 11 and 12 can be passed through holes of the pressing mechanism 25 and attached with fastening parts such as the E-ring 13.

Next, a procedure and an operation for attaching and detaching the thermal head according to the embodiment of the present invention will be described. Attachment / detachment of the thermal head 4 will be described first from the case where the thermal head 4 is attached. The thermal head 4 is attached to the head base 5 with fastening parts such as screws, and the head unit 23 is formed. On the other hand, the pressing mechanism 25
The upper holder 6 and the lower holder 7 are
In this state, a lower unit is formed on the gantry 1, and a spring 8 is inserted between the upper holder 6 and the lower holder 7. Then, it is attached to the lower part of the lower holder 7 via the bracket 9. Thereby,
The pressing mechanism 25 is configured.

In this state, the pins 11 and 12 fixed to the head unit 23 are inserted into the holes of the bent portion of the lower holder 7 from the direction E in FIG. At this point, fastening parts such as the E-ring 13 are attached from the direction F in FIG. Thus, the head unit 23 is attached to the pressing mechanism 25, and the attachment of the thermal head 4 to the gantry 1 is completed.

When the thermal head 4 is to be removed, fastening components such as the E-ring 13 connecting the head unit 23 and the pressing mechanism 25 may be removed. With only this, the thermal head 4 can be removed from the gantry 1 side without disassembling the pressing mechanism 25. Also, even when re-attaching, there is no need to assemble the pressing mechanism 25, so that the thermal head 4 can be easily attached by attaching the E-ring 13 as described above.

When printing with the thermal head,
In the pressing operation (shown in FIG. 2), the thermal head 4
When the lever 2 is lowered in a state where is attached to the gantry 1, the platen 3 comes into contact with the thermal head 4 and pushes it downward, displacing downward against the elasticity of the spring 8.
The pressing force required for printing is obtained, and the thermal head 4
However, since the pins 11 and 12 function as rotation support shafts, even if the platen 3 is tilted left and right, the thermal head 4 closely contacts and tilts along the platen 3, so that even pressure is applied over the printing width. can get. In this state, excellent printing can be performed by driving the platen 3, guiding the supplied rolled paper 14 between the platen and the thermal head, and electrically operating the thermal head 4.

[0023]

The present invention has been described in detail above. Since the mounting portion of the thermal head and the pressing mechanism are separate units and only the former is attached and detached, the attachment and detachment of the thermal head is facilitated. This eliminates the need for assembling and disassembling the printer, thereby contributing to improved printer productivity and maintainability.

Further, since a rotary support shaft is provided at the center of the printing width of the thermal head and the thermal head is tilted following the right and left tilts of the platen, there is no one-side contact, so that the pressing force is uniform over the entire printing width. Pressure is obtained and excellent printing can be realized.

[Brief description of the drawings]

FIG. 1 is a side view and a front view showing an embodiment of the present invention.

FIGS. 2A and 2B are a side view and a front view showing a use state.

FIG. 3 is a front view and a side view showing a conventional example.

FIG. 4 is a side view and a front view showing a use state.

[Explanation of symbols]

 1 Frame 2 Lever 3 Platen 4 Thermal Head 5 Head Base 6 Upper Holder (Sub Frame) 7 Lower Holder 8 Spring (Compression Coil Spring) 9 Bracket 10 Screw 11 Pin 12 Pin 13 E Ring 14 Paper 15 Shaft 16 Stopper 23 Head Unit 25 Press Mechanism

Claims (1)

(57) [Claims] In a printer having a line-type thermal head for printing by a thermal printing method or a thermal transfer printing method, a thermal head opposed to a platen has a mounting portion having a printing width length (sub-scanning direction). In the middle, a pin 11 provided on the sub-frame so as to be rotatably supported by an auxiliary frame pivotally supported by the frame about an axis extending in the main scanning direction .
At least one of the pins 12 is attached to the mounting portion on the thermal head side and the sub-mount by an E-ring 1.
A groove for connection at 3 is formed.
A pressing device for a thermal head, comprising: a pressing mechanism portion upwardly supported by a gantry by a pair of elastic mechanisms 8 provided on the left and right of an intermediate pivot point.