JPH0436929Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a printing mechanism of a printer, and more particularly, to a printing mechanism of a printer that presses a thermal head against a platen to generate heat in a heat generating section to perform printing.

BACKGROUND ART Conventionally, there is a thermal printer that presses a thermal head against heat-melting ink applied to an ink ribbon and transfers the melted ink from the ink ribbon onto recording paper to perform printing.

The printing mechanism of a conventional printer consists of a head base 2 on which a thermal head 1 is attached, as shown in FIG.
The ink ribbon 4 and the recording paper 5 are pressed against the platen 6 by pressing a substantially central position thereof in the direction of the arrow A by the pressing member 3 to perform printing.

Problems to be solved by the invention The above head base 2 and pressing member 3 are
The heat generating part 1a of the thermal head 1 is located at the center of the thermal head 1 so that printing can be done clearly by moving the heat generating part of the thermal head 2 to the ink ribbon 4 immediately after printing is completed. It is located closer to the end. In this way, the heat generating part 1a that presses the platen 6 is further away from the pressing member 3 in the pressing direction, and the head base 2 is attached to the head carriage (not shown) with some play, so thermal The head 1 is tilted with respect to the platen 6, and the heat generating part 1a does not contact the ink ribbon 4 well, resulting in unclear printing.

In order to solve the above problem, a false pressing part 1b is attached to the thermal head 1 as shown by the dashed line in FIG.
There is a method that prevents the thermal head 1 from tilting with respect to the platen 6. However, this has the problem that the pressing force of the heat generating part 1a is approximately half the pressing force of the pressing member 3, and that a false pressing part 1b is required, which increases the manufacturing cost.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a printing mechanism for a printer that solves the above problems by pressing directly behind the heat generating part.

Means for Solving the Problems In the present invention, the thermal head is provided with a heat generating portion near its end. A position immediately behind the heat generating part on the back side of the heat generating part installation surface facing the platen of the thermal head is pressed toward the platen.

Function In the present invention, since the area directly behind the heat generating part is pressed toward the platen, the thermal head is pressed against the platen without being tilted, and clear printing is possible.

Embodiment FIG. 1 is a plan view of an embodiment of the mechanism of the present invention, and FIG.
The figure shows a sectional view of an embodiment of a printer to which the mechanism of the present invention is applied. In both figures, the same parts as in Fig. 3 are given the same reference numerals. In FIG. 2, recording paper 5 is guided by guide member 10 and inserted in the direction of arrow C. The recording paper 5 is transported by a feed roller 11 that is rotationally driven in the direction of arrow D and a presser roller 1 that is rotatably supported.
The ink ribbon 2 is held between the ink ribbon 4 and the ink ribbon 2 , and is sent above the feed roller 11 by the drive of the feed roller 11 and inserted between the ink ribbon 4 and the platen 13 . At this time, the presser roller 12 rotates in the direction of arrow E.

Here, the platen 13 is swingably supported at a fulcrum 15 by a platen guide 14 arranged above the feed roller 11. Further, as shown in FIG. 1, the thermal head 16 is attached and fixed to a head base 17. The head base 17 has its both ends fixed to leg members 18a and 18b.
The leg members 18a, 18b are supported by arm members 19a, 19b fixed to a head carriage (not shown) so as to be rotatable about shafts 20a, 20b, respectively, and a tension member is provided between the head carriage and the leg member 18b. The thermal head 16 is biased in a direction away from the platen 13 by a suspended coil spring 21.

As shown in FIG. 1, the thermal head 16 has blazes 16b and 16c formed near the ends of the leg portions 18a from the center.
A heat generating portion 16a is provided between each of the heat generating portions 6c. As described above, the thermal head 16 is moved in the direction of arrow B by the head carriage to sequentially perform printing. A pressing member 2 is located directly behind the heat generating part 16a of the thermal head 16 of the head base 17 on the back side of the mounting surface of the heat generating part 16a of the thermal head 16.
The two protrusions 22a are in contact with each other.

During printing, this pressing member 22 is pushed in the direction of arrow A by a head up/down drive mechanism (not shown) provided in the head carriage. As a result, the thermal head 16 is connected to the blazes 16b, 1.
6c, the ink ribbon 4 and the recording paper 5 are pushed and pressed against the platen 6. The platen 6 swings about the fulcrum 15, and the heat generating portion 16a is pressed against the platen 6 in a vertical direction. Further, since the convex portion 22a of the pressing member 22 presses the back surface of the heat generating portion 16a of the head base 17, the head base 17 and the arm portion 1
Even if there is some play between the thermal head 16 and the platen 9a and 19b, the thermal head 16 will not tilt with respect to the platen 6, and clear printing can be performed. Also,
Since the thermal head 16 does not need to be provided with a false pressing part as in the past, the pressing force of the pressing member 22 is directly applied to the ink ribbon 4, the recording paper 5, and the platen 6, and the manufacturing cost of the thermal head 16 can be kept low. be able to.

Note that the pressing position of the pressing member 22 may be directly pressed by a spring or the like, and the configuration may be such that, for example, the leg portion 18b is pulled in a direction away from the platen when the head is raised, and is not limited to the above embodiment.

Effects of the invention As mentioned above, the printing mechanism of the printer according to the invention presses the area directly behind the heat generating part toward the platen, so the heat generating part is pressed against the platen without tilting, making it possible to print clearly. Since there is no need to provide a false pressing part as in the above, the pressing force is directly applied to the heat generating part, and the manufacturing cost of the thermal head can be kept low.

[Brief explanation of the drawing]

Figure 1 is a plan view of one embodiment of the mechanism of the present invention;
The figure is a sectional view of an embodiment of a printer to which the mechanism of the present invention is applied, and FIG. 3 is a plan view of an example of a conventional mechanism. 4... Ink ribbon, 5... Recording paper, 6... Platen, 16... Thermal head, 17... Head base, 22... Pressing member.

Claims (1)

[Scope of utility model registration request] In a printing mechanism of a printer that presses a thermal head against a platen and generates heat in a heat generating part provided near the end of the thermal head to perform printing, the heat generated on the back side of the surface on which the heat generating part of the thermal head is provided. A printing mechanism of a printer configured to press a position corresponding to a portion toward the platen.