JPS62263069A - Printing head device - Google Patents

Abstract

PURPOSE:To enable a printing surface of a printing head to be pressed uniformly against a platen, by providing a support shaft guide means for moving a head support in the same direction as a pressing direction of a pressing mechanism, at a support shaft part of the head support. CONSTITUTION:A head support 3 has a lower end part 3A rotatably connected to a fixed support shaft 4A provided on a carrier frame 4, whereby it is connected to the frame 4 so that it can be turned with the support shaft 4A as a fulcrum. The lower end part 3A of the head support 3 is provided with a horizontally elongate slot 3B as a support shaft guide means so that the entire body of the head support 3 can cope with horizontal slight movements and slight rotational movements with the vertical direction as a reference. With the slot 3B provided as the support shaft guide means, two arrays of head elements in a printing surface of the printing head 2 can be brought into uniform contact with a platen 1, and can be pressed against the platen 1 with a uniform pressure. Accordingly, clear printing with a uniform printed density can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a print head device, and particularly to a print head device that employs a two-line printing method.

[Conventional technology]

Conventionally, printers have a head support that is rotatably mounted on a spindle, a print head is installed at the rotating end of the head support, and the print head is further pushed toward the platen via an ink ribbon. Many of them have a configuration that includes a pressure mechanism for separating the print head from the platen side and a retraction mechanism for separating the print head from the platen side.

In this case, the print head is configured to rotate in an arc around the rotation center of the head support (the through hole for connection to the support shaft) described above, and then to be pressed against the platen. Recently, in order to increase the printing speed, for example, thermal transfer printers have become mainstream in which the resistors of the print head are arranged in two rows.

[Problem that the invention seeks to solve]

In the conventional example described above, the connecting through hole of the head support and the support shaft are fitted in a perfect circle with a fit-to-eye tolerance with little play. For this reason, unless the support shaft for the head support is always parallel to the platen axis on the platen side, there is a problem in that uneven contact occurs when the print head is pressed against the platen side. When this uneven contact occurs, in the case of a thermal transfer print head equipped with two rows of resistors,
The difference in the pressing force applied to the resistors in the two rows causes uneven print density, and at the same time, the ribbon wrinkles occur due to the different pressing forces applied to the resistor parts in the two rows. Therefore, in order to reduce such inconvenience,
There is a disadvantage in that processing and assembling the print head requires a lot of labor and skill, including advanced measurement techniques.

[Purpose of the invention]

The present invention improves the drawbacks of the conventional example, and in particular prevents the print head from hitting the platen unevenly,
It is an object of the present invention to provide a print head device with good productivity that can uniformly press the print surface of a print head against a platen.

[Means for solving problems]

The present invention includes a head support rotatably connected to a support shaft, a two-row printing head installed at the rotating end of the head support, and an ink ribbon connected to the print head. and a pressure mechanism that applies pressure to the platen side. The spindle portion of the head support is provided with a spindle guide means for moving the head support in the same direction as the pressing direction of the pressure mechanism.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

The embodiment shown in FIGS. 1 and 2 includes a thermal transfer print head 2 having two resistors 2A and 2B disposed corresponding to printing locations on a platen 1, and this print head 2. A head supporter 3 that fixedly supports the head supporter 3, a carrier frame 4 that rotatably supports the head supporter 3 in the directions of arrows A and B, and a carrier frame 4 that supports the head supporter 3 so as to be rotatable in the directions of arrows A and B, and the head supporter 3 as needed on the platen 1 side. On the other hand, it is provided with a pressurizing mechanism 5 for reciprocating rotation.

The platen 1 is rotatable in any direction about its central axis IA, and is provided with a paper feeding mechanism 10 on its lower surface. The paper feed mechanism IO is composed of a paper guide 11 and pressure rollers 12 and 13 provided at the bottom of the platen 1. Then, the paper 9 fed as indicated by the arrow CI is transferred to the platen 1.
Rotation in the direction of the arrow and pressure rollers 12 and 13
It is sent out in the direction of arrow Ct by the frictional force between the platen L and the platen L.

The head support 3 is rotatably connected at its lower end 3A in FIG. 1 to a fixed support shaft 4A provided on the carrier frame 4, and thereby connected to the carrier frame 4 using the fixed support shaft 4A as a pivot point. Equipped. At the lower end portion 3A of the head support 3 connected to the fixed support shaft 4A, the entire head support 3 is moved slightly in the left and right direction in FIG. An elongated shaft 3B serving as a support shaft guide means is formed parallel to the left-right direction in FIG. 1 so as to be able to accommodate any of the slight rotational movements.

Further, the lower end of the head support 3 in FIG. 1 is provided with a downwardly extending protrusion 3C. This protrusion 3C is equipped with a return spring (compression spring) 16 for rotating the head support 3 in the direction of arrow B.

Due to the action of the return spring 16, the print head 2 is normally set in a released state away from the platen 1.

The carrier frame 4 is equipped with the above-mentioned pressure mechanism 5 inside, and has a ribbon skein/gutter 2o removably attached to the upper part. Among these, the pressurizing mechanism 5 includes a retraction mechanism 6 in a part thereof.

Specifically, the retraction mechanism 6 is a solenoid body 6
A and a plunger part 6B. In addition, the pressurizing mechanism 5 includes this retraction mechanism 6, and further includes a press member 5A attached to the tip of the plunger part 6B.
A compression spring 5B that presses the pressing member 5A toward the platen 1, and a bottle 5c that locks the pressing member 5A to the plunger part 6B with an appropriate attachment play.
A stopper member 5D is fixed to the solenoid body 6A side of the plunger portion 6B. Therefore, when the solenoid main body 6A moves the plunger portion 6B in the right direction in FIG. 1, the entire pressing mechanism 5 acts effectively. On the other hand, when the solenoid body 6A operates the plunger portion 6B to the left in FIG. 1, a so-called retraction operation is performed in which the pressing member 5A of the pressing mechanism 5 is retreated from the platen 1 side.

The ribbon cassette 20 includes a cassette case 21, an ink ribbon 22 installed in the cassette case 21, first and second winding sections 23 and 24 for winding and storing the ink ribbon 22, and the ink ribbon 22. It has a plurality of guide rollers 26, 27, 28 and 29 that guide the travel.

The print head 2 is disposed in a print head placement recess 21A formed in the center of the cassette case 21 on the platen 1 side, and is urged by the pressure mechanism 5 via the ink ribbon 22 as described above. It is guided by the head support 3 and rotates back and forth toward the platen 1 side.

The carrier frame 4 further includes two guide shafts 30.3.
1 and is energized by a drive source (not shown) so that it can reciprocate in a direction parallel to the central axis of the platen 1.

The rest of the configuration is the same as that of a normal printer.

Then, when a print drive command is issued from a control means (not shown), the solenoid main body 6A first drives the plunger 6B to push it out to the right in the figure.

Therefore, the head support 3 rotates in the direction A and presses the print head 2 toward the platen 1 side. In this case, two resistors 2A and 3A arranged on the surface of the print head 2 on the side of the platen 1 are pressed against the platen 1 via the ink ribbon 22. When these two resistors 2A and 3A are pressed against the platen 1, the print head 2 is moved to the head support 3 by the difference in parallelism with the axial direction of the platen 1.
The center of rotation of the head support member 3 rotates slightly due to the effect of the long length 3B of the center of rotation of the head support member 3, and as a result, a so-called yawling effect is produced and the platen 1 is evenly pressed against the platen 1.

Thereafter, as described above, the print head 2 is activated, and at the same time, the carrier frame 4 starts scanning, and high-speed printing is performed on the paper 9 on the platen 1.

In addition, in the above embodiment, the case where the elongated shaft 3B is provided as the guide means for the support shaft provided on the head support body 3 is illustrated, but the present invention is not necessarily limited to this, and any other device that functions in the same manner may be used. It may be replaced by other methods. For example, if the fixed support shaft 4A of the frame 4 is in the form of a cantilever support shaft that protrudes from the left and right sides toward the platen 1, the guide means for the support shaft may be a long groove-shaped member that guides the support shaft. It's okay.

Further, in the above embodiment, the present invention was applied to a print head for a thermal transfer printer equipped with two rows of resistors. The same applies to other printing methods as well.

〔Effect of the invention〕

In the present invention, the retaining portion of the rotational center of the head support relative to the support shaft is provided with an appropriate play (as a guide means for the support shaft) so that it can move perpendicularly to the center axis of the platen and rotate slightly. Because of this, the printing head with the printing surface of the two-row head can uniformly contact the two-row portion of the printing surface against the platen side, which makes it possible to apply uniform pressure. , an excellent print head device with good productivity that can perform clean printing without uneven print density, prevent ribbon wrinkles, and eliminate the need for a lot of labor required for processing and assembly. can be provided.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view showing an embodiment of the present invention;
FIG. 2 is a partially sectional plan view of FIG. 1.

Claims (1)

[Claims] (1) A head support body rotatably connected to a support shaft, a two-row printing type print head installed at the rotating end of this head support body, and a print head connected to the print head via an ink ribbon. In a print head device equipped with a pressure mechanism that applies pressure to the platen side, a support for moving the head support in the same direction as the pressure direction of the pressure mechanism is provided on a support shaft of the head support. A print head device comprising a shaft guide means.