JP4673549B2 - Curved surface printing method by inkjet - Google Patents

Description

  The present invention relates to a printer device that performs printing on a curved print medium using an inkjet device and ultraviolet curable ink.

  Conventionally, as a printing method for a printing medium having an uneven curved surface using a printing plate, there are methods such as flexographic printing and tampo printing. Flexographic printing is suitable for corrugated cardboard printing and the like, and can realize high-speed printing. There is a limit to the deep unevenness of the printing medium beyond the unevenness of the cardboard surface. As a thing with deep unevenness, there is an exterior building material, for example. 2. Description of the Related Art In recent years, an apparatus that uses a low-hardness elastomer rubber-like material as a roller shape and can be printed following the unevenness of a curved surface has appeared. On the other hand, there is a tampo printing method for a curved surface such as a cup surface that does not have very deep irregularities, and it is not suitable for high-speed printing, but the curved surface printing performance is superior to flexo. On the other hand, an ink jet method is used as a technique for printing directly on a print medium using a printer technique aiming at plate-free printing. There is. In this patent, tampo printing is performed by first printing directly on a flat original plate with ink jet, then subjecting the ink on the formed original plate to heat-thickening, then transferring it to a soft pad, transfer printing to a curved medium, and drying. Has been realized.

In recent years, there has been a demand for deep uneven curved surface printing of about 5 mm or more such as a steep groove which is impossible with tampo printing, and there is an increasing demand for high speed and no plate for improving productivity. For this reason, adaptation of inkjet technology is considered.

Inkjet technology generally provides high image quality when the distance between the printing medium and the nozzle is within 2 mm, but the ink droplet flight direction is not determined at 2 mm or more, and the image is collapsed and the curved surface printed image is the image of each medium. Color and image quality change, and it is difficult to obtain a uniform image with the same image quality. In particular, there is a problem that the color and image change or blur when it becomes a color image, and its application to uneven curved surfaces is limited. .
Patent 09-009887

  The problem to be solved is that the ink formed on the printing roll is transferred onto the curved medium in order to obtain a high-quality printed image on the curved medium by inkjet technology, that is, the transferred ink is highly viscous. It is necessary to be. Ink jets are basically limited to a low viscosity of about 1 mPa · s to 20 mPa · s as the ink viscosity capable of ejecting ink. A method that draws an image on a flat plate using a crosslinking agent containing a surfactant and then heat-cures, etc., and then transfers the viscosity from the flat plate to a soft pad by tampo printing after thickening. Is realized.

  It is an object of the present invention to provide a continuous printing method aimed at speeding up a large medium or long medium impossible with tampo printing, and a deep uneven printing medium having a shape such as a groove and having a shape of about 5 mm or more. Thus, there is a need to solve the problem that the curved surface shape and the medium to be used are limited because the ink viscosity and the ink amount cannot be sufficiently controlled only by the amount of ink ejected by inkjet with respect to the uneven curved printed medium.

  The present invention is a UV-curable high-viscosity material for producing ink on a printing roll in a high-viscosity state in order to realize plateless printing on a curved print medium continuously at high speed using inkjet technology. The main feature is that a film is formed by previously applying the film onto a transfer roll or a printing roll, and then drawn on the coating film directly formed and applied using ultraviolet curable ink. In order to enable continuous high-speed operation for large and long curved print media, a transfer roll is prepared so that an image can be drawn on the high-viscosity material film by inkjet and transferred to the print roll in a highly viscous state. Alternatively, a high-viscosity material is applied to the printing roll and an inkjet image is drawn on it.

  As an effect of the present invention, an ultraviolet ray curable transparent high-viscosity ink is applied onto a transfer roll to form an ink film, and then drawn directly on the approximate ink film using the ultraviolet curable ink, whereby a printing medium is obtained. Depending on the type of ink, the thickness of the highly viscous ink can be controlled and optimized. Furthermore, since the ink drawn by the ink jet is almost mixed on the surface of the highly viscous ink, the surface of the highly viscous ink surface becomes the surface when transferred to the printing roll, and it is easy to transfer the viscosity to the printing medium. . Furthermore, as an important effect, it is possible to release the restriction of the material used for the ink when the ultraviolet curable ink for inkjet is gelled by direct thermal curing or ultraviolet curing as disclosed in JP 09-009887, and the viscosity is fixed. Viscosity UV curable color inks may be used.

Using the basic configuration described above, a high-viscosity ink with a viscosity of 10000 mPaS or more coated with a roll coater or blade is applied to an approximate transfer roller, an image is drawn with UV-curable color ink, and this is transferred to a printing roll to improve image quality. Realized transfer of curved print media without damage.

  FIG. 1 is a diagram illustrating a copying state of contact deformation between a printing roll having a substantially low hardness and a printing medium having an uneven curved surface. The printing roll 1 rotates following the movement of the printing medium 8. FIG. 2 is a cross-sectional view of an apparatus showing an embodiment of the method of the present invention. The printing roll 1 rotates in contact with the transfer roller 6 and the printing medium 8. Image formation is performed on the transfer roller 6. The transfer roller generally uses a nitrile rubber rubber material, and the high-viscosity material to be applied is a transparent material that is cured by ultraviolet rays and is made of a material compatible with inkjet ink, such as an acrylic material. A thin film is formed with the same configuration as that of the ink supply multi-roller, and is applied to the transfer roller 6 from the high viscosity ink application roller 7. The thickness of the adhesive film can be determined from the viscosity and the gap between the rollers from 1 μm to several tens of μm.

After the high-viscosity ink is applied, a four-color full-color image is drawn with cyan, magenta, yellow, and black of the inkjet heads 2, 3, 4, and 5. FIG. 3 is a cross-sectional view showing the ink drawing configuration, and shows a state in which the color ink 13 is applied to the liquid of the high-viscosity ink 14 on the transfer roll base 12. The thickness of the highly viscous ink 14 can control ink mixing. For example, when the thickness is several μm or more, it exists near the surface and is easily transferred to a printing roll. The drawn image is transferred to the printing roll 1. The residual ink on the transfer roller 6 is cleaned with the scraping blade 10 in the cleaning unit and the high-viscosity ink 14 is applied again from the high-viscosity ink application roller 7 to enable continuous printing. The sex ink image formed on the printing roll rotates following the movement of the medium on the curved print medium 8, and the ink is finally transferred. Ink solidification and fixing are performed by irradiating the curved surface print medium 8 after image transfer with an ultraviolet lamp so that two types of ink are fixed simultaneously.

In the combination of the transfer roller 6 and the printing roll 1 shown in this embodiment, the diameter, shape, and rubber material of the transfer roller 6 can be selected to ensure stable wetting on the ink surface. Thereby, the diameter and shape of the printing roll 1 can also be set according to the printing medium.

FIG. 4 shows another embodiment in which drawing is performed directly on the printing roll 1, and the application of the high-viscosity ink 14 is performed by the high-viscosity application roller 7 as in FIG. And transferred to the print medium.

In this embodiment, transfer to a limited image quality or print medium is possible. This is an example of a system that can be easily realized at a low price.

  The present invention can be applied to various industrial uses such as uneven material media, that is, outer wall building materials, tiles, curved device covers, operation panels, and interior panels.

It is explanatory drawing which shows the copying contact state of a low-hardness printing roller and a printing medium. Cross-sectional view of the principle explaining the printer apparatus (Example 1) Cross-sectional view showing compatibility of highly viscous ink and inkjet ink It is explanatory drawing which showed drawing directly on the printing roll of this printer apparatus. (Example 2)

Explanation of symbols

1 Printing roll
2 Inkjet head
3 Inkjet head
4 Inkjet head
5 Inkjet head
6 Transfer roller 7 High-viscosity ink application roller 8 Curved printing medium 9 Cleaning roller 10 Scraping blade 11 High-viscosity ink application roller 12 Curved printing medium 13 Color ink 14 High-viscosity ink

Claims (3)

  The ink image formed on the transfer roll in contact with the print roll is transferred to the print roll, and the print roll on which the ink image is formed is contacted and deformed on the print medium having a concave and convex curved surface. In an ink transfer printing method, an ultraviolet curable transparent material having a viscosity of 10,000 mPa · s or more is applied in advance on a transfer roll, and then an image is printed on the material with an ultraviolet curable ink using an inkjet apparatus. Plateless curved surface printing method characterized by forming   In a method of printing on a printing medium having an uneven curved surface by imprinting a printing roll on which an ink image is formed by contact deformation on the printing medium, the ultraviolet ray-curable transparent viscosity of 10000 mPa · s or more is applied onto the printing roll A plateless curved surface printing method, wherein a material is applied in advance, and an image is formed on the material with an ultraviolet curable ink using an inkjet apparatus.   3. The plateless curved surface according to claim 1, wherein the ultraviolet curable transparent material having a viscosity of 10,000 mPa · s or more is a material having compatibility with the ultraviolet curable ink. Printing method.

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