JPS6283166A - Automatic angle adjusting mechanism of thermal printer head - Google Patents

Abstract

PURPOSE:To enhance printing grade, by making a thermal printer head shakable in an automatic angle adjusting manner independently of a head support so as to follow the pressure contact surface of a platen. CONSTITUTION:At the time of printing, a solenoid 6 is excited and a thermal printer head 1 is contacted with a platen 4 under pressure to perform predetermined printing. At this time, the thermal printer head 1 follows the pressure contact surface of the platen 4 and the angle thereof is automatically adjusted around a shaft 11 to always hold said thermal printer head to a vertical state. Because the automatic angle adjustment is performed on the basis of the pressure contact surface of the platen 4 independently of the angle of a head support 10-1, even if the dimensional irregularity of mechanism parts, the change in bending quantity caused by the change in the hardness of the platen with environmental temp., the irregularity in thickness of the recording medium and the irregularity in tension of a thermal ink ribbon 2 in a winding side and a delivery side are generated, the posture of the printing head is well held regardless of various irregularities and, because the thermal ink ribbon 2 generates no skew and no wrinkle, good printing can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an automatic angle adjustment mechanism for a thermal head in a thermal printer that prints image data.

[Conventional technology]

FIG. 2 shows the main parts of a conventional thermal printer.

In the figure, a thermal printer head 1 has several heating elements, and selectively energized dots form an image on a recording medium 3 supported by a platen 4 via a thermal ink ribbon 2. do. This thermal printer head 1 is fixed to a head supporter 10, and a head supporter 101-
1. It is pivotally supported by a shaft 5 fixed to a carriage (not shown) that is slidable in the directions of arrows A and B and facing in the same direction.

Therefore, the thermal printer head 1 is swingable in the directions of arrows C and D about the shaft 5 as a fulcrum, and is biased by the torsion spring 9 in the direction of the arrows.

6 is a solenoid, which is fixed to the above carriage,
Bushing piece 7, spring 8 t-mf. However, the torsion spring 9 has a larger spring force than the spring 8. Therefore, when the Renoid 6 is not excited, the thermal printer head 1 is in the non-printing position at the limit of swing in the direction of the arrow against the spring 8, and the bushing piece 7 is in the retracted position, and the spring 8 is in the retracted position. It is in a compressed state.

Therefore, during printing, when the lensoid 6 is energized, the bushing piece 7 is pushed in the direction of the arrow E, and the thermal printer head 1 swings in the direction of the arrow C together with the head support 10 to press against the platen 4 and perform the above printing. At this time, the spring 8 applies head pressure necessary for thermal transfer. Also, when the excitation of the renoid 6 is released, the thermal printer head 1. The hesode sabot 10 is pulled back by the torsion spring 9, swings in the direction of the arrow, and returns to its original position. Then, while the carriage slides sequentially in the direction of arrow A, the above operation is repeated to form a predetermined print. During this time, the thermal ink ribbon 2 is sequentially wound in the direction of arrow B each time the gear ridge slides.

[Problems to be solved]

In the above conventional example, it is preferable for the thermal printer head li to always be in a vertical state when pressed against the platen 4 in terms of print quality, as will be described later. However, since the thermal printer head 1 is configured to swing around the shaft 5 located substantially below it, the dimensions of the mechanical parts may vary! Change in deflection due to change in platen 4 hardness due to ambient temperature + ae
The thermal printer head 1 does not necessarily stand vertically due to factors such as variations in the thickness of the recording medium 3 and the tension applied to the winding side and the feeding side of the thermal ink ribbon 2. Therefore, the thermal ink ribbon 2 is skewed upward or downward, causing wrinkles in the thermal ink ribbon 2, which tends to smear the print.

[Means for solving problems]

The present invention solves the above problem, and the thermal printer head installed on the head support swingably provided on the carriage prints the thermal ink ribbon e ae through the recording medium as the head support swings. In the structure in which the thermal printer head is in pressure contact with the platen and performs predetermined printing, a predetermined position of the thermal printer head is made to correspond to a predetermined position aVC of the head support and is further swingably provided, so that the thermal printer head contacts the head support during printing. On the other hand, the platen VC is characterized in that it is configured to be able to swing independently, automatically adjust the angle, and come into pressure contact with the platen VC.

〔Example〕

Next, an example thereof will be explained with reference to FIG.

FIG. 1 is a perspective view of the main parts of a printer to which an embodiment of the automatic angle adjustment mechanism for a thermal printer head according to the present invention is applied. In the figure, the same parts as in FIG. 2 are given the same symbols. .

In Fig. 1, the difference between this embodiment and the conventional example (Fig. 2) is as follows.
A head support 10-1, which is pivotally supported by a carriage, has a shaft 11 fixed to the head support 10-1 at the same height as the axis of the platen 4 above the head support 10-1, which extends in the directions of arrows A and B. This point is pivoted to the shaft 11 so as to be swingable in the directions of arrows G and H at the center of the vertical dot row of the heating element groups arranged in several rows in a straight line. The thermal printer head 1 also has a pair of torsion springs 12 and 13 provided on the shaft 11.
Uniform pressure is applied vertically by the head support 10-1, and the head support 10-1 is normally parallel to the head support 10-1.

Next, the printing operation will be explained. During printing, the lunoid 6 is excited as in the conventional example, and the thermal printer head 1 is brought into pressure contact with the platen 4 to perform predetermined printing. At this time, the thermal printer head 1 is connected to the platen 4.
Slightly corrected swinging around axis 11 in directions of arrows G and H following the pressure contact surface.

That is, the angle can be automatically adjusted to maintain a vertical state at all times.

This automatic angle adjustment is performed based on the pressure contact surface of the platen 4 independently of the angle of the hesode sabot (10-1). Even if variations in the thickness of the medium, variations in tension between the take-up side and the feed-out side of the thermal ink ribbon 2 occur, the posture is maintained well regardless of this. Therefore, the thermal ink ribbon 2
Since it does not cause skew or wrinkles, it is possible to perform good printing.

Next, the thermal ink ribbon 2 is driven by a ribbon motor (not shown) or a driving means obtained from the spacing power.
It is wound in the opposite direction of the spacing. At this time, the heat generating elements of the thermal printer head l sequentially form images on the recording medium 3 that is selectively energized. If there is blank data in the middle of the father image, the excitation of the solenoid 6 and the drive of the thermal ink ribbon 2 are stopped, and the thermal ink ribbon 2 is stopped.
This prevents unnecessary feeding.

When one line of printing is completed, solenoid 6 is de-energized,
The thermal printer head 1 is spread, and the carrier returns to the starting position #.

During this carrier return, the I thermal ink ribbon 2 is not driven. After platen 4
rotates, the recording medium 3 is fed, and the first printing operation begins.

〔Effect of the invention〕

As explained above, the present invention enables the thermal printer head to swing automatically at an angle tA uniformly in accordance with the platen pressure contact surface independently of the swing of the head support with respect to the head support. The thermal ink ribbon can be run in a stable manner, and therefore the thermal printer head can be stably suppressed, and the printing quality can be significantly improved.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the main parts of a printer to which an embodiment of the automatic angle adjustment mechanism for a thermal printer head according to the present invention is applied, and Fig. 2 is a perspective view of the main parts of a printer to which a conventional thermal printer head is applied. It is a diagram.

Claims (1)

[Claims] In a configuration in which a thermal printer head installed on a head support swingably provided on a carriage comes into pressure contact with a platen via a thermal ink ribbon and a recording medium as the head support swings, and performs predetermined printing, A predetermined position of the thermal printer head is made to correspond to a predetermined position of the head support and is further provided to be swingable, and during printing, the thermal printer head further swings independently relative to the head support to automatically adjust the angle. An automatic angle adjustment mechanism for a thermal printer head, characterized in that it is configured to be in pressure contact with the thermal printer head.