JPS641085Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a thermal transfer printer that improves the quality of images transferred to photographic paper by eliminating slack that occurs in the ribbon that passes between the press-bonding platen and the thermal head. be.

FIG. 1 is a schematic diagram of a conventional thermal transfer printer, in which 1 is a platen, 2 is a paper attaching/detaching mechanism provided in the notch of the platen 1, 3 is a thermal head that is pressed against the platen 1, and 4 is a sheet with a thickness of 100 μm. Ranked photographic paper, 5
is a ribbon approximately 20 μm thick that is impregnated or coated with dye, etc. Note that A is the width of the platen 1, and B is the width of the platen 1.
is the width of the photographic paper 4 and the ribbon 5, and C is the printing range, which is usually set in the relationship A>B>C.

When printing with the thermal transfer printer configured as described above, first, one end of the photographic paper 4 is fixed by the paper attachment/detachment mechanism 2, and the photographic paper 4 is placed around the platen 1.
Wrap around. When the photographic paper 4 comes into pressure contact with the thermal head 3 through the ribbon 5, a signal corresponding to the information to be printed is applied to the thermal head 3, and the dye on the ribbon 5 is transferred to the photographic paper by the heat generated by the thermal head 3. The images were transferred and printed.

In this case, since the width A of the platen 1 is larger than the width B of the photographic paper 4 and the ribbon 5, the photographic paper 4 and the ribbon 5 are pressed against the platen 1 by the thermal head 3 over their entire width. However, since the printing range C is usually narrower than the width B, the printing paper 4 and the ribbon 5 have a portion that is heated by the thermal head 3, that is, a printing range C, and a portion that is not heated. Since the photographic paper 4 is thick at 100 μm, there is almost no change due to heating, but since the ribbon 5 is thin at 20 μm, changes due to heating become a problem.

The changes in the ribbon due to this heating will be explained with reference to FIG.

In FIG. 2, 5a is a portion of the ribbon 5 that is heated and corresponds to the printing range C, and 5b is a portion of the ribbon 5 that is not heated.

As mentioned above, during printing, heat shrinkage occurs in the portion 5a of the ribbon 5 due to heating by the heat-sensitive head 3, but since the portion 5b is originally an area that is not printed, it is not heated by the heat-sensitive head 3, so the heat shrinkage occurs. doesn't happen. Therefore, slack occurs in the shaded portion of portion 5b, and the portions 5a and 5b
The boundary is the most common. However, since the entire width of the ribbon 5 is crimped to the platen 1 by the thermal head 3, there is no escape for the slack due to thermal contraction, and the ribbon 5 is pulled to absorb the slack, resulting in wrinkles. . As a result, the thermal head 3 cannot come into uniform contact with the ribbon 5, resulting in disadvantages such as uneven print density and missing prints.

This idea was made in view of the above points, and provides a thermal transfer printer in which the printing area is limited to the pressure bonded portion between the platen and the thermal head, and the slack generated in the ribbon is released to improve the printing quality. It is something. This invention will be explained below based on the drawings.

FIG. 3 is a plan view showing an embodiment of this invention, in which numeral 11 is a platen, and a protrusion 12 is formed with only the width corresponding to the printing range C having a large diameter. Other symbols are the same parts as in FIGS. 1 and 2.

Since the platen 11 of this embodiment has the protrusion 12 formed only in the printing range C, the platen 11 and the thermal head 3 are pressed together only in the printing range C. Therefore, even if the ribbon 5 becomes slack when heated by the heat-sensitive head 3, the portion 5b
Since the ribbon 5 is not crimped, the slack of the ribbon 5 can be released at this portion, and the print quality will not be affected.

FIG. 4 is a plan view showing another embodiment of this invention, in which numeral 13 is a thermal head, in which only the width corresponding to the printing range C is formed as a protrusion 14. Other symbols are the same parts as in FIGS. 1 and 2.

In this embodiment, as in the embodiment shown in FIG. 3, the portion 5b of the ribbon 5 where the slack occurs is not pressed between the platen 1 and the thermal head 13, so that the slack that occurs in the ribbon 5 can be released. It does not affect print quality.

FIG. 5 is a plan view showing still another embodiment of this invention, in which protrusions 12 and 14 are formed on both the platen 11 and the heat-sensitive head 13.

In the case of this embodiment as well, the slack generated in the ribbon 5 can be released and the print quality will not be affected.

As explained above, in the thermal transfer printer of this invention, a protrusion is provided on the platen and/or the thermal head so that the pressure bond between the platen and the thermal head is limited to the printing area, so that the slack that occurs in the ribbon can be released. This has the advantage of eliminating uneven print density and improving print quality.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a conventional thermal transfer printer.
Fig. 2 is a plan view of the ribbon, Fig. 3 is a plan view showing one embodiment of this invention, Fig. 4 is a plan view showing another embodiment of this invention, and Fig. 5 is a plan view showing still another embodiment. FIG. In the figure, 1 and 11 are platens, 3 and 13 are thermal heads, 4 is photographic paper, 5 is a ribbon, 12 and 14 are protrusions, and C is a printing range.

Claims (1)

[Scope of utility model registration request] In a thermal transfer printer that prints by inserting photographic paper and a ribbon between the platen and the thermal head to be crimped, the platen and/or the thermal head are arranged so that the area crimped by the platen and the thermal head is the only area to be printed. A thermal transfer printer characterized by having a protruding part.