JPH0699597A - Thermal head opening/closing mechanism - Google Patents

Abstract

PURPOSE:To reduce ink ribbon consumption, by automatically opening/closing the thermal print head of a thermal printer, thereby feeding printing paper only. CONSTITUTION:With a compression spring 10 sandwiched between head plates A3 and B4, a thermal head 2 is fixed to the head plate A3 and is brought into contact with a platen 1. A cam B9 is arranged between a head open plate 8 and it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for automatically opening and closing a thermal head in a thermal printer.

[0002]

2. Description of the Related Art As shown in FIG. 4, in a conventional thermal printer, since a thermal head is pressed against a platen roller at a required pressure, an ink ribbon and a printing paper are conveyed while being in close contact with each other even when not printing. It

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to save the ink ribbon when not printing. In the prior art, when the print portion A shown in FIG. 3 has an extremely small ratio in the C direction with respect to the fed printing paper B, the ink ribbon is also fed by the same amount and is not printed. The part is wasted. In order to solve the above problems, when printing, the thermal head and the platen are brought into pressure contact with each other to send out the ink ribbon and the printing paper at the same time. It is necessary to separate and stop the ink ribbon. There was a need for a device that automatically separates or presses the thermal head and platen.

[0004]

According to the present invention, as shown in FIG. 1, a thermal head 2 has a compression spring 10 sandwiched between a head plate A3 and a head plate B4, and a thermal force is generated by a spring force with an axis A12 as a fulcrum. The head 2 is in pressure contact with the platen 1. A cam A6 is arranged opposite to the head plate A3, and its posture changes depending on whether the thermal head 2 is in a printing operation or not. Head plate A
3 and the head open plate 8 fixed to the head plate A3, the cam B9 is disposed between the head open plate 8 and the head open plate 8, and when the cam A6 is in a printing operation, the cam B9 using a motor as a power source is rotated to It is possible to create a state in which the platen 1 and 2 are pressed against each other and a state in which the thermal head 2 and the platen 1 are separated.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an outline of an ink ribbon and a conveyance path for printing paper in normal printing will be briefly described. In FIG. 1, an ink ribbon sent from a ribbon reel is pressed against a thermal head 2 and a platen 1 using a guide 14 as a guide. Sent out. Further, the printing paper sent from the printing paper reel is guided by the guide roller 13, and is pressed against the thermal head 2 and the platen 1 and sent out. At this time, printing is performed by energizing the thermal head. Next, the printing mechanism section will be described. When setting the printing paper and the ink ribbon, referring to FIG. 5, the thermal head 2 is fixed to the head plate 3 by screws, and the head plate A3 and the head plate B4 are supported by the shaft A12. The open plate 5, which is fixed to the head plate B4 by a screw, rotates the lever 7 by 180 degrees in the D direction to rotate the cam A6 that is linked with the lever 7. The spring force of the compression spring 10 causes the head plate to rotate. B4 hits the hook 11 and the head plate A3 and the head plate B4 become one body and are pulled up. Then, the thermal head 2 fixed to the head plate 3A is also pulled up, and a gap can be provided between the thermal head 2 and the platen 1. On the other hand, when printing,
As shown in the drawing, when the cam A6 is rotated 180 degrees in the E direction from the position shown in FIG. 5, the head plate A3 is pushed down by the spring force of the compression spring 10 sandwiched between the head plate A3 and the head plate B4 and the thermal head 2 and the platen. 1 can be pressed. In the latter printable state described above, when the head opening / closing mechanism of this apparatus is described with reference to FIG. 6, when it is determined that there is an unprinted portion after normal printing, the head is fixed to the axis B19. Cam B9 arranged between the head open plate 8 and the head plate A3
Is rotated by the worm gear 17 and the worm wheel 18 by energizing the motor 16 of the power source for a certain period of time, turns on the sensor 26 arranged opposite the axis B19, rotates 90 degrees in the F direction, and opens the head. The plate 8 is lifted up, and further the head plate A3 and the thermal head 2 fixed to the head open plate 8 are lifted up to give a gap between the thermal head 2 and the platen 1. At this time, roller A24 and roller B25
Therefore, only the printing paper is sent out, and the ink ribbon is not sent out because it is not pressed against the thermal head 2 and the platen 1. Next, when it is determined that there is a print portion, the head open plate 8 is released by rotating the cam B9 by 90 degrees in the G direction from this state, and the spring force of the compression 10 pushes down the head plate A3 and the thermal head 2. 26 is turned off and stops, and the thermal head 2
And the platen 1 can be pressed again. The amount of ribbon used can be minimized by determining the print pattern and repeating such operations. Also, cam B
The position of 9 does not necessarily have to be between the head plate A3 and the head plate B4, but the platen 1 can be pulled down to provide a gap between the platen 1 and the thermal head 2.

[0006]

As described above, according to the present invention, since the thermal head 2 and the platen 1 can be automatically provided with a gap or pressed against each other, only the printing paper is fed, as compared with the method of feeding the jammed ink ribbon and the printing paper at the same time. In addition, the amount of ink ribbon used can be minimized and great value can be found in terms of cost.

[Brief description of drawings]

[Fig. 1] Side view of the device

[Fig. 2] Front view of this device

[Fig. 3] Relationship between printing area and printing paper

[Fig. 4] Side view of the printing mechanism of the conventional machine

[Fig. 5] Side view of printing mechanism section when setting paper

[Fig. 6] Side view of the rear part of the printing machine when the thermal head opening / closing mechanism is operating

[Explanation of symbols]

 1. Platen 2. Thermal head 3. Head plate A 4. Head plate B 5. Open plate 6. Cam A 7. Lever 8. Head open plate 9. Cam B 10. Compression spring 11. Hook 12. Axis A 13. Guide roller 14. Guide 15. Motor stand 16. Motor 17. Worm gear 18. Worm wheel 19. Axis B 24. Roller A 25. Roller B 26. sensor

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 9305-2C B41J 3/20 117 A 25/30 U

Claims (1)

[Claims] A common structure that has a print sheet to be conveyed, at least a resistance layer and an ink layer, presses an energizing head against a rotatable platen with the conveyed ink ribbon in between, and contacts the resistance layer of the ink ribbon from the thermal head. In a thermal printing device that passes a current according to a recording signal between the electrodes and heats the ink ribbon to melt or sublime the ink and transfer it to the recording paper, to save the ink ribbon, print only the printing paper when not printing. Automatic thermal head opening / closing mechanism for feeding