JPS63107577A - Printing head driver - Google Patents

Abstract

PURPOSE:To increase the durability of a printing head by lessening, by a method wherein the displacement of an outer peripheral part caused by the rotary action of a cam mechanism is composed of a compression spring, a cam follower for transmitting the displacement onto a pressing one side, an original position return means of a cam follower side member, and a control motor for rotary driving the cam mechanism. CONSTITUTION:When a plane cam 6 is rotated in the C direction by driving a control motor 7, a cam follower 5 is pushed out in the A direction. Therefore, the compression spring and a pressing piece 3 engaged in the cam follower 5 are pushed out the platen side and at the same time, a printing head 1 together with the pressing piece 3 is pushed out to the platen 2 side. When the printing head 1 approaches paper 10, the advance speed of this printing head 1 becomes lower by the action of the plane cam 6 and the printing head 1 is gently pressed onto the printing paper 10 via an ink ribbon 11. Thereby, the life of the printing head 1 can be prolonged and an impulse mark due to the pressure sensitivity of the ink ribbon 11 never remain.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a print head drive device, and particularly to a print head drive device equipped with a print head pressing means in a thermal transfer printer.

[Conventional technology]

Conventionally, thermal transfer printers have adopted a method of bringing a print head into contact with paper on the platen side when printing. In this case, means for pressing the print head against;
In most cases, solenoids, which are relatively easy to control, are used.

[Problem that the invention seeks to solve]

In the above-mentioned conventional example, due to the nature of the solenoid, the action of pressing the print head toward the platen is rapid, and in many cases, the print head collides with the platen with an impact.

As a result, not only a large amount of impact noise is generated, but also the print head is easily damaged. In addition, impact marks from the print head are likely to be transferred onto the printing paper due to the pressure sensitivity of the ink ribbon, resulting in the inconvenience that the printing paper becomes smeared.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a print head drive device that improves the disadvantages of the conventional example, reduces impact noise, and significantly increases the durability of the print head.

[Means for solving problems]

The present invention includes a pressing piece and a compression spring.

A pressing means is provided for pressing the print head toward the platen via this pressing piece and a compression spring. This pressing means is
A cam mechanism, a cam floor that transmits the displacement of the outer circumference caused by the rotational operation of the cam mechanism to a compression spring and one side of the press, means for returning these cam floor side members to their original positions, and a control motor that rotationally drives the cam mechanism. We have adopted methods such as configuring the system using the following methods.

[First Embodiment of the Invention] Hereinafter, a first embodiment of the present invention will be described based on FIG.

In FIG. 1, the print head drive device includes a print head 1
It is provided with a pressing piece 3 and a compression spring 4 that press the platen 2 side (in the direction of arrow A). The compression spring 4 has a function of determining a pressing force for appropriately pressing the print head 1 against the platen 2 side. A planar cam 6 as a cam mechanism is in contact with the pressing piece 3 and the compression spring 4 via a cam floor 5 as shown in the figure. The pressing piece 3, the compression spring 4, and the cam floor 5 are guided by a guide (not shown) and are allowed to move only in directions A and B in the figure. As the planar cam 6, an elliptical planar cam is used. A pressing means 9 is formed by the pressing piece 3, the compression spring 4, the cam floor 5, the planar cam 6, and the original position return means (not shown).

The planar cam 6 has a rotary drive shaft 6A at a position where a predetermined amount of tin is formed.
is fixed. A control motor 7 is connected to this rotational drive shaft 6A. The cam floor 5 is equipped with a tension spring (not shown) as means for returning to its original position. As a result, the cam floor 5 is constantly pulled in the direction B.

The print head drive device formed in this way is mounted on a carriage (not shown) including the print head 1 so that it can freely reciprocate in the left and right directions in FIG. 1 along the rotation axis of the platen 2. It has become.

Since the planar cam 6 has an elliptical shape as described above, the pressing acceleration against the cam floor 5 when it rotates gradually decreases near the end point and finally becomes zero.

Now, in order to print, the control motor 7 is driven and the planar cam 6
When the cam floor 5 is rotated in the C direction, the cam floor 5 is pushed out in the incoming direction. Therefore, the compression spring 4 and the pressing piece 3 engaged with the cam floor 5 are pushed out toward the platen 2, and at the same time, the print head 1 is pushed out together with the pressing piece 3 toward the platen 2. Then, when the print head 1 approaches the paper 10, the print head 1 moves forward at a slow speed due to the action of the planar cam 6, and is gently pressed against the print paper 10 via the ink ribbon 11.

As described above, in this embodiment, the planar cam 6 is rotated by the control motor 7, and the printing head 1 is pressed against the platen 2 side by the action of the planar cam 6, so that the print head 1 is smoothly printed without any impact. This has the advantage that the print head 1 can be pressed against the print paper 10, the life of the print head 1 can be extended, and there are no impact marks left due to pressure sensitivity of the ink ribbon 11.

[Second Embodiment] Next, a second embodiment of the present invention will be described based on FIGS. 2 and 3.

In the embodiment shown in FIG. 2, a displacement adjusting means 20 is provided between the rotational drive shaft 6A of the planar cam 6 and the planar cam 6 in the embodiment shown in FIG.

This displacement adjusting means 20 is arranged on a rotary drive shaft 6A as shown in the figure.
It is comprised of an eccentric bushing 21 which is eccentrically mounted and has an unevenness formed on its outer periphery, and a fitting hole portion 22 which has an unevenness formed on its inner diameter side corresponding to the eccentric bushing 21.

The fitting hole 22 is eccentrically formed in the drive shaft portion of the planar cam 6 as shown in FIG.

The other configurations are the same as those of the first embodiment described above.

In this second embodiment, in addition to having the same functions and effects as the first embodiment described above, the eccentric bushing 21 of the displacement adjusting means 20 and the fitting hole 22 of the planar cam 6 are fitted together by mutually rotating little by little. By aligning them, the rotation center position of the planar cam 6 can be changed, and thereby the movement stroke of the cam floor 5 in the platen 2 direction can be changed. As a result, the amount of compression of the compression spring 4 changes, and the contact pressing force of the print head 1 against the platen 2 side can be effectively changed.

Therefore, there is an advantage that the pressing force of the print head can be easily adjusted depending on the thickness of the printing paper, the roughness of the surface, the pressure sensitivity of the ink ribbon, etc.

[Third example] Next, a third embodiment will be described based on FIG. 4.

The embodiment shown in FIG. 4 differs from the first embodiment described above in that a roller 4o is provided on the cam floor 5.
is configured so that it comes into contact with the planar cam 6. The other configurations are the same as those of the first embodiment described above.

Even in this case, in addition to having the same effect as the first embodiment described above, in particular, the mutual movement between the cam floor 5 and the planar cam 6 can be performed smoothly, and damage due to wear of both is reduced, resulting in improved durability. Since the cam floor 5 and the planar cam 6 come into rolling contact with each other, the rotational driving force of the planar cam 6 is significantly reduced, so the drive motor 7 can be downsized. There are advantages to getting it.

In each of the above embodiments, a planar cam 6 having an elliptical diameter is used, but a circular eccentric cam may also be used. Further, cam mechanisms of other shapes may be used as long as they can reciprocate the cam floor 5 with a predetermined change in rotation.

Furthermore, as for the displacement adjustment means 20 in the second embodiment, a means with jagged protrusions and recesses was used as the means for engaging the two, but even if it is gear-like, other means, such as a cross-like means, may be used. A locking means may be used.

〔Effect of the invention〕

Since the present invention is configured and functions as described above, it is possible to not only effectively push the print head toward the platen side, but also prevent collision of the print head with the platen side, It is possible to provide an unprecedented and excellent print head drive device that can drastically reduce the generation of noise and increase the durability of the print head.

[Brief explanation of the drawing]

FIG. 1 is a partially omitted plan view showing a first embodiment of the present invention, FIG. 2 is a partially omitted plan view showing a second embodiment, and FIG.
This figure is an explanatory view showing the planar cam in FIG. 2, and FIG. 4 is a plan view showing the third embodiment. l...print head, 2...platen,
3... Pressing piece, 4... Compression spring, 5...
...Cam floor, 6 ... Planar cam as cam mechanism, 9 ... Pressing means, 20 ...
・Displacement adjustment means. 1 person for patent use Japan Electric Co., Ltd. agent Patent attorney Yuji Takahashi~, 1 Figure 1 n Figure 2 Figure 3

Claims (2)

[Claims] (1) In a print head drive device equipped with a pressing means that presses the print head toward the platen side via a pressing piece and a compression spring, the pressing means is equipped with a cam mechanism and an outer periphery generated by the rotational movement of the cam mechanism. A print head drive comprising: a cam floor that transmits the displacement of the part to the compression spring and the pressing side; means for returning these cam floor side members to their original positions; and a control motor that rotationally drives the cam mechanism. Device. (2) In a print head drive device equipped with a pressing means for pressing the print head toward the platen via a pressing piece and a compression spring, the pressing means is provided with a cam mechanism and an outer periphery generated by the rotational movement of the cam mechanism. a cam floor that transmits the displacement of the part to the compression spring and the pressing side, means for returning these cam floor side members to their original positions, and a control motor that rotationally drives the cam mechanism, the cam mechanism and the cam mechanism A print head drive device characterized in that a displacement adjustment means is provided between the rotation drive shaft and the rotation drive shaft.