JP3293923B2 - Laser marking method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for printing by irradiating a laser beam to a surface of a base material such as a packaging container.

[0002]

2. Description of the Related Art Various types of printing are performed on blanks used for packaging containers of beverages and foods, but the date of manufacture and the manufacturing factory are not described in the process of manufacturing blanks. It is more convenient to print directly on the surface of the container in a separate step, such as when filling the container or after the container is completed. Here, there is known a method of irradiating a printing surface such as a container with a laser to sublimate the printing and print white characters.

[0003]

However, since paper containers require water resistance, the printed surface of the base material is often coated with polyethylene or the like to form a surface layer. When a laser is applied to the printing surface on which the surface layer has been formed, the surface layer bursts due to heat, water vapor, gas, and other pressure generated when the print sublimates, making the printing difficult to read and the characters being unclear and unreadable. There is a problem that it is difficult. Accordingly, an object of the present invention is to provide a printing method using a laser that does not rupture the surface layer.

[0004]

Means for Solving the Problems In order to achieve this object,
Printing is performed on the surface of the base material, peeled off from the printing surface to form a surface layer of a material that transmits laser, and sublimation of the printing on the surface of the base material is performed by irradiating a laser from above the surface layer to print. The configuration was adopted.

[0005]

The surface of the substrate is irradiated with a laser beam through the surface layer to sublimate the printing to print desired characters, figures, and the like.
Since the surface layer separates from the printing surface, the surface layer separates from the surface of the base material due to heat, water vapor, and pressure of gas generated when the print sublimates, and the generated water vapor or gas accumulates in a gap formed between the two. And the internal pressure is reduced so that the surface layer does not burst.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a substrate 1 according to an embodiment of the present invention. A print 2 is applied to the surface of the substrate 1, and a surface layer 4 is formed on the print 2 via a release layer 3. The base material 1 can be made of various materials such as paper and resin materials used for packaging containers and the like, and metal plates such as aluminum and iron. Ink, paint, or the like is uniformly or entirely printed on the surface of the substrate 1. The release layer 3 is formed by gravure printing, applying, or the like, a material that does not allow the printed surface 2 to adhere to the surface layer 4 or a material that allows the surface layer 4 to be pseudo-adhered to such an extent that the surface layer 4 can be easily removed. . The surface layer 4 is formed of a material that transmits laser, such as polyethylene, polypropylene, polyethylene terephthalate, and polyvinylidene chloride. The release layer 3 may be provided so as to cover the entire print 2 as shown in FIG.
As shown in FIG. 3, a release layer 3 may be partially provided on the print 2 and the surface layer 4 and the print surface 2 may be partially adhered. When the surface layer 4 and the printing surface 2 are partially adhered in this manner, there is an advantage that there is no fear that the surface layer 4 is peeled off in a blank punching step or the like. Although not shown, a release layer may be formed on a part of the printing surface.

FIG. 4 shows a laser irradiation device, and a laser transmitter 1 controlled by a controller 10.
1 and a power supply 12, a laser 13 oscillated from a laser oscillator 11 passes inside a beam tube 14 while being reflected by mirrors 15, 16 and 17, and is formed into a desired shape by a stencil (template) 18. The laser 19 passes through a lens 20 and is irradiated on a packaging container 22 conveyed by a conveyor 21. A sensor 23 is disposed on the side of the conveyor 21. The sensor 23 detects the packaging container 22 and outputs a signal to the module 2
When transmitted to the laser oscillator via 4, the laser beam is irradiated for a certain period of time. Further, a protective cover 25 is provided so as to cover the upper part of the conveyor 21. The laser transmitter 11 has a configuration in which a pair of electrodes is provided in a glass tube in which a mixed gas obtained by adding an auxiliary material such as nitrogen or helium to carbon dioxide as needed is pressurized and sealed. Gas molecules are ionized by ultraviolet rays generated by the arc discharge, and a carbon dioxide laser is oscillated.

FIG. 5 is an enlarged view of a portion where the packaging container 22 is irradiated with a laser. In the illustrated example, a stencil 18 is provided with a hole 26 having an “A” shape. A laser 13 oscillated from a laser oscillator 11 strikes a stencil (template) 18 and is shaped into an “A” shape, and a laser 19 shaped in such a manner passes through a lens 20 and irradiates a packaging container 22.

The packaging container 22 as described above is composed of the base material 1 described with reference to FIGS. 1 to 3, and is irradiated with a laser while conveying the packaging container 22 by a conveyor 21 in an irradiation device. 22, a laser 19 having a predetermined shape is applied to the surface of the base material through the surface layer 4 on
Is partially sublimated, and the white characters 27 are printed. Since the polyethylene or polypropylene forming the surface layer 4 has a property of transmitting the laser energy without absorbing it, the laser 19 can be directly irradiated on the printing surface 2 of the base material 1. By irradiating the substrate 1 with the laser 19 in this way, generating a short pulse with the light energy in the infrared light contained in the laser, and removing the printing 2 such as ink and paint on the irradiated portion, The base is exposed in a predetermined shape, and characters, figures, and the like are printed with white characters 27. Thus, in the present invention, since the surface layer 4 is configured to be peeled off from the surface of the base material, as shown in FIG. 6, this occurs when the print 2 is sublimated by laser energy to print the character 27. The surface layer 4 is separated from the surface of the substrate 1 by the pressure of sublimation heat, water vapor, gas, or the like, and a gap 5 is formed between the two. Then, since water vapor and gas accumulate in the gap 5, the internal pressure is reduced, so that no excessive force is applied to the surface layer 4 and the gap does not burst.

However, according to the printing method using a laser as described above, printing can be performed only by irradiating a laser in a very short time of one millionth of a unit.
No matter how fast the transfer speed is, printing can be made clearly. In addition, high-speed, high-quality printing can be performed without fear of ink or paint scattering. Various printing can be performed by replacing the stencil 18, and printing can be performed on an ultra-small object such as a microchip or an aluminum foil.

[0011]

According to the present invention, since the surface layer is separated from the surface of the base material by the pressure of heat, water vapor, gas or the like generated when the printing sublimates, the water vapor is formed in the gap formed between the two. And the gas accumulates, the internal pressure decreases, and the surface layer does not burst. Accordingly, by irradiating the surface of the base material with a laser beam through the surface layer, the printing can be sublimated and desired characters, figures, and the like can be printed, and high-speed, high-quality printing can be performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a substrate.

FIG. 2 is a perspective view of a base material.

FIG. 3 is a perspective view of a substrate in which a surface layer and a printing surface are partially adhered.

FIG. 4 is a block diagram of a laser irradiation apparatus.

FIG. 5 is an enlarged view of a laser irradiation part.

FIG. 6 is a cross-sectional view showing a state in which a surface layer has been peeled off from the surface of a base material.

[Explanation of symbols]

 DESCRIPTION OF REFERENCE NUMERALS 1 base material 2 printing 3 release layer 4 surface layer 5 gap

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41M 5 / 26,5 / 36 B41M 5/38-5/40

Claims (1)

(57) [Claims] (1) printing on the surface of a substrate, and peeling off the printed surface;
Separated to form a surface layer of a laser-permeable material
And, by irradiating the laser from above the surface layer, the substrate
A laser characterized by sublimation printing on the surface.
User printing method.