JPS6030553B2 - Method and device for preventing wrinkles on transfer film in pad type thermal transfer machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for preventing wrinkles in a transfer film in a pad-type thermal transfer machine intended for articles whose transfer surface is a three-dimensional curved surface, The purpose of this invention is to reliably prevent the occurrence of scratches on the transfer surface and to ensure good transfer to the transfer surface.

By the way, when attempting to transfer onto the transfer surface of an article using a transfer film, it is necessary to heat and press the film against the transfer surface, and the transfer surface is a three-dimensional curved surface. In this case, in order to properly apply the film to the entire surface of the film, it is necessary to cause the film to stretch to some extent.

Therefore, in a thermal transfer machine intended for an article whose transfer surface is a three-dimensional curved surface, a transfer pad made of a heat-resistant elastic material with high elasticity is employed.

When this pad is strongly pressed against the surface to be transferred, it causes elastic deformation to match the curved shape of the surface, and the pad is brought into pressure contact with the surface so as to press the surface to be transferred by its multiple elasticity. By heating the pad and pressing the pad against the surface to be transferred with a transfer film interposed between the pad and the surface to be transferred, the transfer film will be heated by the pad and will be able to perform the required amount of heat. It is supposed to be applied to the surface to be transferred with elongation and pressurized, thereby realizing the transfer to the surface. On the other hand, elongation of the transferred transfer film during transfer is caused by the film being tensed.

Such elongation does not occur uniformly over the entire range used for each transfer of the transfer film, but is likely to occur mainly in and around the area where elongation is required, depending on the shape of the surface to be transferred. shall be. Therefore, the tension state for causing elongation is not uniform over the entire application range of the transfer film, but differs from part to part, and the more elongation is required, the stronger the tension is applied. The uniformity and condition of this transfer film is
If the above elongation occurs quickly by the required amount, then
easily uniformized.

However, there is a limit to the elongation of the transfer film, and the required elongation will not occur quickly even if the film is strongly tensed. Therefore, it is difficult to actually make the tension state uniform for causing elongation. Under such uneven tension conditions, undesirable wrinkling occurs in the transfer film. These wrinkles occur along the tension direction of the transfer film,
The more the film is strained, the more serious the problem becomes. Since these wrinkles are directly heated and pressed by the transfer pad, they impede the realization of good transfer. The present invention utilizes vibrations of an appropriate frequency, such as ultrasonic vibrations, in order to address the above-mentioned conventional problems and reliably prevent wrinkles that tend to occur in transfer films. It is.

That is, the features of the wrinkle prevention method according to the present invention are as follows:
While applying vibrations of an appropriate frequency to the transfer film stretched against the transfer surface of the object to be transferred, through the object,
The wrinkle prevention device according to the present invention is characterized in that the film is heated and pressed against the surface to be transferred, and the wrinkle prevention device according to the present invention is characterized by the use of a suitable vibration generator in a pick-up tool that holds the object to be transferred. The output end is inserted to apply vibrations of an appropriate frequency to the article held by the pick-up tool. These details will be described below with reference to an embodiment in which ultrasonic vibrations as shown in the drawings are used. In the figure, 1 is an article to be transferred, for example, a cap-shaped molded article, and in this embodiment, the area from the top surface to the circumferential surface is intended to be the transfer surface, and 2 is the article. It is assumed that the transfer film used for the transfer is continuous in a long length in the left and right direction of the figure.

Reference numeral 3 denotes a sling for holding the article 1, which is basically cylindrical in shape and has a cavity 4 inside, and is mounted on a jig 5 so as to stand up.

Reference numeral 6 denotes a machine stand, and the above-mentioned jig stand 5 is fixed to the upper surface of this machine stand.

Reference numeral 7 denotes an ultrasonic vibration generator that includes a built-in ultrasonic transducer of the Shigeru-strain type or Dew-strain type. It is held within the machine base by a lower seat 10 attached to the machine.

Reference numeral 11 denotes a focusing horn as a vibration energy output end that projects upward from the upper end of the ultrasonic vibration generator described above, and penetrates through the upper part of the coupling 6 and the jig 5 to connect the cavity 4 of the jig 3. It is inserted from below.

In the illustrated example, the horn 11 does not come into contact with the jig 3, but its tip is directed toward the inside of the top surface of the article 1 held by the pick-up tool. However, if the shape of the article 1 is such that it is difficult to bring the horn 11 into direct contact with it, the horn 11 may be brought into contact with the pick-up tool 3 that holds the article. Reference numeral 12 denotes a transfer pad made of a heat-resistant elastic material, which is attached to the lower surface of the transfer head 14 by a pad support frame 13 in order to be positioned above the jig 3, and is operated by a head support mechanism and an elevating mechanism (not shown). It can be raised and lowered at any time.

Reference numerals 15 and 16 are tight rollers for guiding and tensioning the long transfer film 2 described above. During transfer, it is lowered to a position below the surface of the article 1 to be transferred.

It is assumed that the transfer pad 12 is internally or externally provided with a heater for heating at least its pressurizing surface, that is, the bottom surface in the illustrated example, to a required transfer temperature. In the above-described configuration, first, the object 1 to be transferred is transferred to the jig 3.
and then the tight roller 5 of the transfer film 2,
16 is lowered and the film is applied to the transfer surface of the article 1 as shown by the iron wire in FIG. 1 while being strongly tensioned.

Then, the transfer film 2 tends to elongate as required to follow the three-dimensional curved shape of the surface to be transferred, and along with this, wrinkles also tend to occur. Therefore, the vibrator in the ultrasonic vibration generator 7 is vibrated, for example, at a frequency of 20K.
Generates ultrasonic vibrations of about Hz and transmits them to the Shuto horn 1.
1 to item 1. Note that the amplitude of the ultrasonic vibration used here is preferably small, unlike that used in ultrasonic machining, and is therefore on the order of 5 to 10 r. The ultrasonic vibration transmitted in this manner has at least a vibration component perpendicular to the surface of the transfer film 2, that is, in the vertical direction in the illustrated example, and preferably has a vibration component parallel to the surface of the transfer film 2, that is, in addition to the above-mentioned component. In the illustrated example, it is assumed that there is also a horizontal vibration component in the front, back, left, and right directions. When such ultrasonic vibrations are transmitted to the article 1, the vibrations are also transmitted to the transfer film 2 applied to the transfer surface of the article, causing a subtle change in the tension state of the film.

In other words, the vertical vibration component in the example shown in the figure changes the tension of the transfer film 2, which is in a tense state, to a stronger or weaker state, so it is impossible to increase the elongation required for the film, even if there is a difference in the degree of elongation in some parts. to occur quickly and without any problems. Therefore, the initially uneven tension state of the transfer film 2 is easily made uniform, and the wrinkles that were about to occur disappear. Furthermore, when the above-mentioned vibration has a horizontal vibration component in the example shown in the figure, this vibration component should promote the close contact of the transfer film 2 to the transfer surface, which is a three-dimensional curved surface. This promotes uniformity and eliminates the dispersion of wrinkles that were about to occur around them. On the other hand, the transfer pad 12, which is kept on standby in the raised position and whose pressurizing surface is heated to a required temperature, is used to transfer the transfer film 2 onto the surface to be transferred in a wrinkle-free state as described above. , is lowered by the transfer head 14,
The pressing surface is pressed against the transfer surface of the article 1 via the transfer film 2 as shown in FIG. Then, since the transfer pad 12 itself is highly elastic, a large elastic deformation occurs on the pressing surface side. This elastic deformation occurs in the dirty portion of the pressurized surface so as to match the shape of the top surface of the article 1,
It bulges out at the peripheral portion and surrounds the portion extending from the top surface to the peripheral surface of the article. When the transfer pad 12 is pressed in this way, the transfer film 2 is likely to stretch a little further, albeit partially, and there is therefore a risk that wrinkles will occur again.

Therefore, the ultrasonic vibration described above is still applied to the article 1 at this point. Then, the above-mentioned elongation that is newly required for the transfer film 2 is caused quickly and easily in the same manner as described above, and therefore no wrinkles are generated at this point. Further, the ultrasonic vibrations applied to the article 1 while the transfer pad 12 is being pressed as described above causes the aforementioned elastic deformation of the pad to properly match the shape of the surface to be transferred of the article. Therefore, the transfer film 2 interposed between the two is reliably brought into pressure contact with the entire surface to be transferred.
Furthermore, the ultrasonic vibrations at this time change the pressure force applied by the transfer pad 12 to the transfer film 2 to be stronger or weaker, so that the pad presses the film 2 so as to slam it against the surface to be transferred. However, since the ultrasonic vibrations that act on the transfer film 2 and the transfer pad 12 during transfer as described above have small amplitudes as described above, they may cause the transfer film 2 to elongate more than necessary or may cause damage during transfer. There is no possibility of the transfer pad 12 slipping on the film,
Therefore, there is no concern that this vibration will affect thermal transfer.

Therefore, the transfer film 2 is correctly attached to the transfer surface in a state where only the required elongation has occurred without any wrinkles, and is heated by the transfer pad 12 and pressed in the above-described manner. , the image will be transferred well to the transfer target surface.

In addition, in the above-mentioned embodiment, ultrasonic vibration is used as vibration of an appropriate frequency to be applied to the transfer film 2,
Therefore, as the vibration source, an ultrasonic vibration generator 7 is used, which uses the Shuto horn 11 as an output end of vibration energy.

However, the frequency of vibration that should be applied to the transfer film 2 is
The film is not limited to the range of ultrasonic vibration, but even if low frequency vibration in a range lower than this range is applied to the film 2, wrinkle prevention of the film can be similarly achieved. Therefore, as a vibration source to be adopted, in addition to the generator 7 with a built-in ultrasonic vibrator as shown in the figure, there is also a generator 7 that can generate low frequency vibration electromagnetically or mechanically. good. However, no matter what frequency of vibration is used, it is desirable that its amplitude be as small as possible. As described above, the present invention involves applying vibrations of an appropriate frequency to a transfer film that is stretched against the transfer surface of an article to be transferred, and heating the film to the transfer surface. Therefore, according to the present invention, even when the object to be transferred is a three-dimensional curved surface, the transfer film can be applied with pressure. It is possible to reliably prevent the formation of wrinkles while causing only the required elongation, and the effect of easily realizing good transfer to the transfer surface can be expected.

[Brief explanation of the drawing]

FIG. 1 is a partially cut-out front view showing an embodiment of the present invention, and FIG. 2 is a cut-out enlarged front view showing the transfer state of the rhombus. 1... Article to be transferred, 2... Transfer film, 3... Common odor, 4... Hollow, 6...
・Machine base, 7... Ultrasonic vibration generator, 11...
... Shuto horn, 12 ... Transfer pad, 14
...Transfer head. Kagiha period 2nd figure

Claims (1)

[Scope of Claims] 1. In a pad-type thermal transfer machine intended for articles whose transfer surface is a three-dimensional curved surface, the above transfer film is tensioned along the transfer surface. Vibration at an appropriate frequency is applied through the article to cause the required elongation, and the film is subsequently heated and pressed against the transfer surface while applying the above-mentioned vibration to the film. A method for preventing wrinkles in a transfer film in a pad-type thermal transfer machine, characterized by: 2. In a pad-type thermal transfer machine that targets articles whose transfer surface is a three-dimensional curved surface, a vibration generator is installed in an article-holding jig placed below a transfer pad that can be raised and lowered at any time. An apparatus for preventing wrinkles of a transfer film in a pad-type thermal transfer machine, wherein an output end of the transfer film is inserted and the output end is brought into direct contact with an article held by the jig.