JP2789608B2 - Light disk - Google Patents

Description

The present invention relates to an optical disk provided with a multicolor printing unit, and is applied to an audio disk, a video disk, a computer digital disk, etc., which read digital signals with a laser beam. Is what you can do.

(B) Conventional technology In general, an optical disc has a recording surface formed on one surface of a transparent substrate depending on the presence or absence of pits, and a reflective film and a protective layer are sequentially formed on the recording surface, and the optical disk is formed on the protective layer. Printing section.

This printing part is formed by silk printing using an acrylic solvent type ink.

(C) Problems to be Solved by the Invention In the conventional silk printing, the thickness of the silk printing at one time is so large that a delicate pattern cannot be expressed, and multicolor printing is difficult. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide an optical disk having a multicolor printing portion capable of expressing a delicate pattern.

(D) Means for Solving the Problems According to the method for manufacturing an optical disk of the present invention according to claim 1, in order to achieve the above object, a protective layer for protecting a reflective film formed on an information recording surface of a transparent substrate. A method for manufacturing an optical disk having a printed thereon, comprising: a first step of offset printing an acrylic ultraviolet curable ink on the protective layer using a flat plate without water; and an acrylic printed by the first step. And a second step of irradiating the system ultraviolet curable ink with ultraviolet rays.

The method for manufacturing an optical disk according to the present invention according to claim 2 is a method for manufacturing an optical disk in which printing is performed on a protective layer that protects a reflective film formed on an information recording surface of a transparent substrate, using a flat plate without water. A third step of offset printing acrylic ultraviolet curable ink on the protective layer, and a fourth step of offset printing acrylic ultraviolet curable inks of a plurality of colors by repeating the third step a desired number of times. When,
A fifth step of irradiating the acrylic ultraviolet curable ink of a plurality of colors, which is offset-printed in the fourth step, with ultraviolet light.
And a step.

(E) Action The acrylic ultraviolet curable ink is transferred onto a protective layer of a disk by offset printing using a waterless lithographic plate (printing plate), and then cured by irradiation with ultraviolet light.
The above operation is repeated for different ink colors, and multi-color printing is performed.

The multicolor printed portion obtained by curing the acrylic ultraviolet curable ink obtained in this manner is made of acrylic ultraviolet curable ink. Fine and delicate patterns can be obtained compared to those obtained by printing.

(F) Example An example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of an optical disk. In this drawing, the optical disk comprises a disk disk 1 and a printing unit 2. The disk disk 1 is formed by injection molding of a polycarbonate resin in a mold having a stamper, and a transparent substrate 4 having an upper surface as a recording surface 3 by the stamper. And an aluminum reflective film 5 formed on the recording surface 3 by vapor deposition, and a protective layer 6 formed on the reflective film by acrylic resin spin coating.

The printing unit 2 is formed as a multicolor printing unit by curing an acrylic ultraviolet curable ink. As the acrylic UV-curable ink, a polyester acrylate resin ink is used. This ink is transferred onto the protective layer 6 of the disk 1 by offset printing using a lithographic plate (printing plate) without water. FIG. 2 shows an enlarged sectional view of the waterless planographic plate. As is apparent from this drawing, the waterless planographic plate 7 is composed of a substrate 8, a primer layer 9, a photosensitive layer 10, and a silicone rubber layer 11.
The upper surface 12 of this silicone rubber layer becomes a non-image area because it repels ink, and is approximately 2 μm without the silicone rubber layer.
The concave portion 13 becomes an image portion where ink is received. Therefore, the ink 14 adheres to the image area as shown by the broken line.

The ink is transferred onto the protective layer 6 by offset printing using such a waterless lithographic plate, and is cured by irradiation with ultraviolet rays to form a cured thin film. This offset printing operation is performed for each color of ink to perform multi-color printing.

FIG. 3 is a plan view of an offset printing apparatus for printing five colors. The printing apparatus has a rotary table 15 which is used to hold a disk 1 with a protective layer 6 on top.
The position is intermittently positioned at each position. This rotary table has a support frame 16 in a substantially direction and a receiving table 17 sliding on the support frame at positions equally divided into 10 in the circumferential direction, and is stacked on a rotary supply table 18 in the first station. The disk board 1 is suctioned by the supply handler 19 and supplied onto the receiving table 17. In the second, fourth, fifth, seventh and eighth stations, acrylic UV curable inks of different colors are sequentially applied onto the disc 1. The third, sixth and ninth stations are ultraviolet irradiation stations. The tenth station sucks the disk 1 on which the offset printing has been completed by the discharge handler 20 and discharges the disk onto the rotary discharge table 21.

At the second, fourth, fifth, seventh and eighth stations for applying the ink, as shown in FIG. 4, a blanket roller 22 and a printing plate 7 which are in pressure contact with the disk 1 mounted on the receiving table 17 are attached. Roller 23, ink supply rollers 24, 25, 26, 27, rollers for adjusting the amount of ink supply and eliminating uneven supply
28 and 29 and an ink tank 30 are provided. At each station of the ink application, the ink 14 accumulated in the concave portion 13 of the printing plate 7 is transferred onto the receiving board 17 via the blanket roller 22 onto the disk 1. At the time of this transfer, the support 17 is
16, the ink is transferred in a flat state on the disk board 1.

The disk board 1 supplied to the first station by the supply handler 19 is sent to the second station by the rotation of the turntable 15, and the white ink is transferred at the second station. Subsequently, it is sent to the third station by the rotation of the rotary table 15, where ultraviolet light is irradiated to cure the white ink. Similarly, in the fourth station, the black ink is transferred to the disk 1 in the fifth station, and in the fifth station, the black ink and the dark ink are cured by irradiating ultraviolet rays in the sixth station. At the seventh station, all-color ink is transferred onto the disk 1 at the eighth station, and at the ninth station, ultraviolet light is irradiated to cure the all-ink and yellow link. Then disk 1 sent to the 10th station
Is discharged onto the rotary discharge table 21 by the discharge handler 20.

Thus, the acrylic ultraviolet curable ink has a higher ink viscosity than the acrylic solvent ink used for silk printing, and the third, sixth, and ninth offset printing apparatuses use the same.
2-4 by UV irradiation at the station
A μm cured thin film is formed. On the other hand, in silk printing, by curing by ultraviolet irradiation or heat application, 10 to 20
μm in thickness, and the film thickness is relatively large compared to the case of forming a multicolor printing part by curing the acrylic ultraviolet curable ink. Therefore, it is difficult to perform multicolor printing by silk printing, and the viscosity of the ink This makes it difficult to display delicate patterns.

Next, the polycarbonate resin, which is the material of the transparent substrate 4 of the disk board 1, increases the fluidity during injection molding.
A resin having a molecular weight of about 15,000 is used, which has a molecular weight smaller than that of a normal polycarbonate resin having a molecular weight of 40,000 to 50,000. For this reason, the strength against stress is relatively reduced. Since this stress is also given by irradiation with ultraviolet rays, it is desirable to reduce the number of times of irradiation of ultraviolet rays for curing the acrylic ultraviolet curable ink as much as possible. Therefore, in the embodiment, in the sixth and ninth stations,
Two color inks are cured at the same time. In this case, as the two colors of ink, it is desirable that the amount of ink of each color is small and that the hue of each ink is close. If this requirement is satisfied, it is possible to simultaneously cure three or more color inks.

(G) Effect of the Invention The present invention is to form a multicolored printed portion by curing an acrylic ultraviolet curable ink, and therefore to provide an optical disk which delicately expresses a pattern on a protective layer of a disk disk. Can be.

Further, according to the present invention, since the offset printing process is repeated a desired number of times to print the acrylic UV curable inks of a plurality of colors and then irradiate the UV rays, the stress applied to the disk substrate can be reduced.

[Brief description of the drawings]

1 is a partial sectional view of an optical disk, FIG. 2 is a partial sectional view of a waterless lithographic plate, FIG. 3 is a plan view of an offset printing apparatus, and FIG. It is a side view of the ink application station in an apparatus. 1 ... disk board, 2 ... printing section, 3 ... recording surface, 4 ...
... Transparent substrate, 5 ... Reflection film, 6 ... Protective layer.

Claims (2)

(57) [Claims] 1. A method for manufacturing an optical disc, wherein a protective layer for protecting a reflective film formed on an information recording surface of a transparent substrate is printed on the optical disc, wherein an acrylic ultraviolet ray is formed on the protective layer using a waterless flat plate. A method of manufacturing an optical disc, comprising: a first step of offset printing of a curable ink; and a second step of irradiating ultraviolet rays to the acrylic ultraviolet curable ink that has been offset-printed in the first step. 2. A method for manufacturing an optical disc, wherein a protective layer for protecting a reflective film formed on an information recording surface of a transparent substrate is printed, wherein an acrylic ultraviolet ray is formed on the protective layer by using a waterless flat plate. A third step of offset printing the curable ink; a fourth step of offset printing the acrylic ultraviolet curable ink of a plurality of colors by repeating the third step only a desired number of times; Fifth irradiation of ultraviolet rays to the printed acrylic ultraviolet curable ink of multiple colors
A method for manufacturing an optical disk, comprising: