JPS6114959B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a curved surface printing method for transferring a pattern printed on a film onto a printing substrate.

This type of printing method involves floating a transfer film on which a transfer pattern has been printed in advance on the liquid surface, and
A method is known in which the printing material is pressed against the liquid and allowed to settle in the liquid, thereby bringing the transfer film into close contact with the printing material using the hydraulic pressure.

However, this printing method requires a liquid tank to suspend the transfer film, which increases the size of the device, and the need to keep the liquid surface smooth makes it difficult to use the liquid tank continuously to dissipate waves. Furthermore, air bubbles often remain between the transfer film and the printing material, which has the disadvantage of deteriorating the printing effect.

The present invention aims to provide a curved surface printing method that can eliminate the above-mentioned disadvantages.

The method of the present invention will be explained below with reference to the accompanying drawings. The method of the present invention includes a pattern printing step A in which a transfer pattern 2 is printed on a swellable film, for example, a film 1 made of polyvinyl alcohol to form a transfer film 3; The transfer film 3 is spread in the transfer chamber 4 with the transfer pattern 2 facing in the transfer direction, for example, upward, and the transfer film 3 is moistened by spraying, and the air pressure P ₁ on the transfer pattern 2 side of the transfer film 3 is increased. A transfer step B in which the transfer film 3 is brought into close contact with the printing material 5 by using a pressure difference _P2 lower than the pressure P2 on the other side of the transfer film 3, and after the transfer step, the transfer film 3 is
The present invention is characterized by having a film removing step C for removing the film 1 of.

The above pattern printing process may or may not be connected to the transfer process depending on the time. In the former case, as shown in FIG.
A printing means 6 for printing the transfer pattern 2 on the transfer chamber 4 is arranged in front of the transfer chamber 4.

On the other hand, when the printing process is temporally separated from the transfer process, a large number of transfer films 3 that have been printed in advance in the printing process (not shown) are stored and are spread out in the transfer process as required. Become.

In such a case, the pattern 2 of the transfer film 3 is usually dry, so the pattern 2 of the transfer film 3 is dry.
It is necessary to dissolve the ink in a solvent such as nitrocellulose or carbitol alone or in a mixture.

For this reason, in this method, as shown in FIG. 2, there is a pattern activation step A' for dissolving the ink and paint of the transfer pattern 2 before the transfer chamber 4, and it is necessary to provide a dissolving means 7 in this step. becomes.

In this embodiment, since the transfer film 3 on which the transfer pattern 2 is printed in advance can be used, there are advantages such as ease of use of the transfer film and the possibility of multicolor printing.

In the above transfer process, the transfer film 3 is usually spread out so that the transfer pattern 2 is directed upward as shown in the figure, but in some cases, the transfer film 3 is set so that the transfer pattern 2 is directed downward or to the side. Also good,
The differential pressure generated on both sides of the transfer film 3 may be obtained only by the vacuum suction means 8 as shown in FIG. 1, or by the vacuum suction means 8 and the pressurized air supply means 9 as shown in FIG. You may use it together.

However, it is preferable that the differential pressure generating means be configured to suck air from the side of the printing medium 5, so that the effect of removing air bubbles between the printing medium 5 and the transfer film 3 is further improved.

The wetting means in the above transfer process is carried out to swell the film 1 of the transfer film 3, so care must be taken to prevent the printing ink or paint from dissolving due to this. or steam.

In the film removal step, the film may be peeled off by physical treatment, dissolved by chemical treatment, or eliminated by biological treatment, thereby exposing the transferred pattern 2. Good.

Since the method of the present invention is as described above, the transfer film 3 spread in the transfer chamber 4 is wetted and the transfer pattern 2 side is pressed against the printing material 5 by high back pressure as shown in FIG. The transfer pattern 2 is transferred to the surface of the printing material 5 while being swollen by this, and then in the film removal process, the film 1 is removed as shown in FIG.
is removed, transfer pattern 2 to printing material 5
The printing material 5 is printed with residual exposure on the surface of the printing material 5.

Since the method of the present invention is as described above, it has the advantage of being able to print on curved surfaces without using a liquid tank, and the air pressure applied to the transfer film 3 can be adapted to the type of printing substrate 5 and the printing process. There are also effects that can cause change.

Therefore, the method of the present invention is highly effective when applied to curved surface printing, the demand of which will increase in the future.

[Brief explanation of the drawing]

FIGS. 1 and 2 are schematic diagrams for explaining an embodiment of the method of the present invention, and FIGS. 3 and 4 are schematic diagrams for explaining the steps of the same method. In the figure, 1 is a film, 2 is a transfer pattern, 3 is a transfer film, 4 is a transfer chamber, 5 is a printing medium, 6 is a printing means, 7 is a pattern activation means, 8 is a vacuum suction means as a differential pressure generating means, 9 indicates the same pressure air supply means.

Claims (1)

[Claims] 1. Stretch the transfer film, which is a swellable film with a transfer pattern printed on it, so that the transfer pattern is located on the side to be printed, and while moistening the stretched transfer film, make the pressure on the side of the transfer pattern lower than the pressure on the other side. A printing method characterized in that a transfer film is brought into close contact with a printing material by back pressure with a relative reduction, and then the film of the transfer film is removed to expose the transferred pattern remaining on the surface of the printing material.