JPH07290798A - Thermal printer - Google Patents

Abstract

PURPOSE:To provide a thermal printer wherein a head-up of a thermal head can be executed uniformly against a platen. CONSTITUTION:A hook shape section 2a of a heat radiation plate 2 adhered by a thermal knead 1 is engaged with a head mounting pin 4 freely to rotate. A plate spring 6 pressing the thermal head to a platen 5 is integrated with a spring mounting plate 7, and the spring mounting plate 7 is engaged with and adhered to an upper section of the frame 3. Top edges of screws respectively screwed into width direction both sides sections of the spring mounting plate 7 in order to prevent the spring mounting plate 7 from becoming out of place from the frame 3 is made to execute a near access to the hook shape state section 2a. A fear wherein the hook shape state section 2 a may come up from a pin 4, when the head-up of the heat radiation plate 2 is executed, is prevented by the screws 18 of the width direction both sides. By this, a uniform head-up quantity along all width is ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal printer, and more particularly to a structure for solving a problem that occurs when heading up.

[0002]

2. Description of the Related Art A conventional thermal printer is shown in FIGS. As shown in these drawings, the thermal head 1 which is a main component of the thermal printer has a structure that can be easily removed from the thermal printer main body.

That is, in the heat dissipation plate 2 to which the thermal head 1 is adhered, the hook-shaped portion 2a provided at the rear end is hooked on the head attachment pins 4 attached to the left and right frames 3, and the upper portion of the same frame 3 is hooked. The platen 5 is pressed by a plate spring 6 integrated with the upper lid 7 attached to the platen 5.

The upper lid 7 is relatively raised by pressing the screws 8 screwed into both side portions thereof onto the upper end surfaces of the left and right frames 3, so that the fitting holes 7b formed in both side portions of the upper lid 7 in the width direction are formed. While fitting into the fitting convex portion 3b of the frame 3, pressing the rear side portion of the upper lid 7 against the upper portion of the rear side engaging groove 3c of the frame 3,
This upper lid 7 is prevented from coming off the frame 3.

When the thermal head 1 is cleaned, as shown in FIG. 4 (B), first, the upper lid removal preventing screw 8 is loosened to resist the reaction force of the leaf spring 6 and move the upper lid 7 in the a direction. Push in and slide in the direction of (b) to remove the fitting hole 7b of the upper lid 7 from the fitting convex portion 3b of the frame 3, and further remove the upper lid 7 in the direction of C as shown in FIG.
By moving the heat radiating plate 2 in the direction of C, the hook-shaped portion 2a of the heat radiating plate 2 can be removed from the pin 4 of the frame 3 and the thermal head 1 can be easily removed.

As shown in FIG. 3, a head-up cam 9 is rotatably and pivotally supported on one side surface of the frame 3.
A head-up pin 10 protruding from one side surface of the heat dissipation plate 2 is engaged with the peripheral surface of the head-up cam 9.

When it is desired to temporarily raise the head of the thermal head 1 by replacing the printing paper, the head-up cam 9 is rotated by the cam lever 9a, and the heat radiating plate 2 is moved.
The thermal head 1 is separated from the platen 5 by pushing up the head-up pin 10 attached to one side surface of the platen 5.

[0008]

At this time, the b portion is also lifted by raising the a portion of the heat dissipation plate 2 in FIG. 3, but at the same time, the c portion of the hook-shaped portion 2a is also lifted from the pin 4, and as a result, , The amount of lifting of the b portion is smaller than that of the a portion.

Conventionally, in order to reduce the floating amount of the c portion of the hook-shaped portion 2a from the pin 4, as shown in FIG. 4 (A), the hook-shaped portion of the heat sink 2 is attached to the upper lid 7 as shown in FIG. A convex portion 7a for reducing the gap with 2a is integrally provided.

However, as shown in FIG. 4 (B), the upper lid 7
In order to move the fitting hole 7b of the upper lid 7 to the lower side of the fitting convex portion 3b of the frame 3 when removing the frame from the frame 3, as shown in FIG. 4 (A), the convex portion 7a of the upper lid 7 and the heat sink 2 are removed. A certain gap L is required between the hook-shaped portion 2a and the hook-shaped portion 2a.

As described above, in the case of the conventional device, the gap L is unavoidable in consideration of the detachability of the upper lid 7, and therefore, FIG.
It is impossible to prevent the floating of the c part of the
It is not possible to eliminate the difference in the amount of lifting of parts.

In other words, when the head-up cam 9 lifts the head-up pin 10, the hook-shaped portion of the heat dissipation plate 2
The c part of 2a floats above the pin 4 of the frame 3,
As a result, the head-up amount from the platen 5 of the thermal head 1 is not uniform on the left and right, and the thermal head 1 is partially
There is a drawback that the gap between the platen 5 and the platen 5 becomes small.

If this gap becomes small, the insertability of the print-receiving paper into the thermal printer will deteriorate significantly. Further, if the amount of head-up movement is increased, the leaf spring 6 will be burdened and the pressing force will decrease, resulting in the problem that the printing quality will deteriorate.

The present invention has been proposed to solve the above problems, and an object of the present invention is to provide a thermal printer capable of uniformly performing head-up of a thermal head with respect to a platen. .

[0015]

According to the present invention, a hook-shaped portion provided as a rotation base portion on a heat dissipation plate of a thermal head is rotatably engaged with a rotation fulcrum portion of a frame. In a thermal printer in which a spring mounting plate having a spring for pressing the spring to the platen side is detachably engaged with a frame, the spring mounting plate is screwed from both side portions in the width direction of the spring mounting plate, In the thermal printer, the tips of the screws for pressing in the direction are arranged close to both side portions in the width direction of the hook-shaped portion.

[0016]

According to the present invention, a screw is screwed in from both sides in the width direction of the spring mounting plate, and the tip of the screw is arranged close to both sides in the width direction of the hook-shaped portion which is the rotation base of the heat dissipation plate. The hook-shaped part is prevented from rising from the pivotal fulcrum part of the frame when it is raised.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in FIGS.

FIG. 1 is a side sectional view of a thermal head mounting structure to which the present invention is applied. As shown in this figure, the thermal head 1 is adhered to the lower surface of an aluminum radiator plate 2. A hook-shaped portion 2a integrally formed as a rotation base portion on the rear portion of the heat dissipation plate 2 is attached to the left and right frames 3, and a head mounting pin 4 as a rotation fulcrum portion.
Rotatably engage with.

The thermal head 1 is pressed against the platen 5 by a leaf spring 6, and the leaf spring 6 is integrally attached to an upper lid 7 serving as a spring mounting plate which is attached to the frame 3 and the upper lid 7 thereof is attached. A screw 18 for preventing the upper lid from coming off is screwed from the upper lid 7 to a proximity position facing the hook-shaped portion 2a of the heat radiating plate 2.

As shown in FIG. 2, the top cover removal preventing screw 18 is mounted inside the left and right frames 3 and is screwed into both side portions of the top cover 7 in the width direction. The position of this screw 18 is the same as that of the conventional upper lid projection 7a (Fig. 3).
Is provided and is screwed in place of the conventional convex portion 7a.

In the engaging structure of the upper lid 7 provided on the upper portion of the frame 3, a front engaging groove 3a which engages with the front side portion of the upper lid 7 is horizontally cut and formed, and an upper portion of the engaging groove 3a is formed. Fitting holes 7b drilled in the front end portions on both sides in the width direction of the upper lid 7.
And a fitting protrusion 3b that can be fitted and removed freely. Further, a rear side engaging groove 3c that engages with the rear side portion of the upper lid 7 is formed in the horizontal direction so as to face the front side engaging groove 3a, and the rear side engaging groove 3c is formed.
Engaging portions 3d that engage with the rear end portions of the upper lid 7 on both sides in the width direction are provided on the upper part of the.

As shown in FIG. 2, a head-up cam 9 is rotatably supported on one side surface of the frame 3,
A head-up pin 10 protruding from the side surface of the heat dissipation plate 2 is slidably engaged with the peripheral surface of the head-up cam 9. The head-up cam 9 is integrally formed with a cam lever 9a.

As shown in FIG. 1, a paper insertion port 11 and a paper insertion passage 12 for inserting a printing target paper are provided on the lower side of the platen 5. A printing paper guide plate 13 for guiding the printing paper between the platen 5 and the thermal head 1 is attached. Further, another paper insertion port 14 is provided in the lower part of the printer body, and a paper insertion path 15 is provided from the paper insertion port 14 along the print-target paper guide plate 13.
Is provided. Either one of the paper insertion paths 12 and 15 is selected and used.

When the thermal head 1 is to be removed in such a structure, first, the upper lid removal preventing screw 18 is loosened,
As in the conventional case (FIG. 4), the upper lid 7 is resisted against the reaction force of the leaf spring 6.
Is pushed downwards, and the fitting hole 7b is inserted into the fitting projection of the frame 3.
3b, slide the upper lid 7 backward, remove the front portion of the upper lid 7 from the engaging groove 3a of the frame 3, lift the front portion of the upper lid 7 and pull it out obliquely from the frame 3, then the heat dissipation plate of the thermal head 1 2 can also be removed from the frame 3.

On the other hand, when the upper lid 7 is attached to the frame 3, the upper lid removal preventing screw 18 located above the hook-shaped portion 2a of the heat sink 2 is screwed into the upper lid 7 and the tip of the screw 18 is inserted. By inserting the hook-shaped portion 2a close to the hook-shaped portion 2a, it is possible to prevent the hook-shaped portion 2a of the heat dissipation plate 2 from rising from the pin 4 on both sides in the width direction, and when the head is raised by the cam 9. It is possible to make the lifting amount of the portions a and b in FIG. 2 constant.

The spring mounting plate 7 is pressed and locked onto the upper portions of the engagement grooves 3a and 3c of the frame 3 by the reaction force of the plate spring 6 pressing the heat dissipation plate 2 downward. At this time,
It is desirable to provide a very small gap between the lower end of the upper lid removal preventing screw 18 and the hook-shaped portion 2a of the heat dissipation plate 2 so as not to hinder the rotation of the hook-shaped portion 2a.

[0027]

According to the present invention, it is possible to prevent the spring mounting plate from coming off and to prevent partial lifting of the hook-shaped portion of the heat dissipation plate by using the screw screwed into the spring mounting plate. Therefore, during head-up, there is an advantage that the thermal head can be uniformly rotated over the entire width, the thermal head can be moved back and forth in parallel with respect to the platen over the entire width, and the head-up amount can be constant over the entire width. This leads to an improvement in the insertability of the printing target paper into the thermal printer and an improvement in the printing quality.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a thermal printer of the present invention.

FIG. 2 is a plan view of the same thermal printer.

FIG. 3 is a perspective view showing a conventional thermal printer.

4A, 4B, and 4C are cross-sectional views for explaining the problems of the conventional thermal printer.

[Explanation of symbols]

 1 Thermal Head 2 Heat Dissipator 2a Hook Shape 3 Frame 4 Head Mounting Pin as Rotation Support 5 Platen 6 Leaf Spring 7 Upper Lid as Spring Mounting Plate 18 Screw

Claims (1)

[Claims] 1. A spring for pressing a thermal head to a platen side by a hook-shaped portion provided as a rotary base portion of a heat dissipation plate of the thermal head being rotatably engaged with a rotary fulcrum portion of a frame. In a thermal printer having a spring mounting plate that is detachably attached to a frame, the spring attaching plate is screwed from both sides in the width direction of the spring attaching plate, and the tip of the screw that presses the spring attaching plate in the attaching direction is A thermal printer, wherein the thermal printer is arranged adjacent to both side portions in the width direction of the hook-shaped portion.