JPH0268788A - Optical disk - Google Patents

Abstract

PURPOSE:To express a fine pattern on the protecting layer of a disk board by forming a multicolor printing part by curing an acrylic ultraviolet-curing type ink. CONSTITUTION:The acrylic ultraviolet-curing type ink is transferred onto a protecting layer 6 of the disk board by an offset printing through the use of a waterless planographic plate (machine plate) and, thereafter, cured by the irradiation of an ultraviolet, radiation. The above-mentioned operation is repeated by changing the color of the ink to be different, and the multicolor printing is executed. Since a multicolor printing part 2 formed by the curing of the acrylic ultraviolet-curing type ink obtained in such a way is made of the acrylic ultraviolet-curing type ink, the film thickness of a thin film due to the curing of the ink in each color is thin, and the fine pattern can be obtained.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to an optical disc equipped with a multicolor printing section, and is suitable for audio discs, video discs, digital discs for computers, etc. that read digital signals using a laser beam. Conventional techniques (i): i Optical discs have a recording surface formed by the presence or absence of bits on one surface of a transparent substrate, and a reflective film and a protective film on this recording surface. It consists of a disc on which layers are sequentially formed and a printing section formed on the protective layer.

This printed portion is formed by silk printing using acrylic solvent-based ink.

(c) Problems to be Solved by the Invention With conventional silk printing, the -1151 thickness of the silk printing is thick, making it impossible to express delicate patterns and making it difficult to print in multiple colors. Ta.

The present invention was invented based on these points, and A! !
1. It is an object of the present invention to provide an optical disc on which a multicolor printing part is formed that can express a dark blue pattern.

(d) Means for Solving the Problems In order to solve the problems, the present invention forms a multicolor printed portion by curing an acrylic ultraviolet curable ink.

(E) Function The acrylic ultraviolet curing type ink is transferred onto the protective layer of the disc by offset printing using a waterless lithographic plate (printing plate), and then hardened by irradiation with ultraviolet light.

The above operation IP is repeated using different ink colors to print in multiple colors.

The thus obtained multicolor printed area, which is formed by curing the acrylic ultraviolet curable ink, is made of acrylic ultraviolet curable ink. Compared to silk printing,
A thin, delicate pattern can be obtained.

(f) Example An embodiment of the present invention will be described based on the drawings.

FIG. 1 is a sectional view of an optical disc. In this drawing, the optical disc consists of a disc disk 1 and a printing section 2. The disc disk 1 is formed by injection molding of polycarbonate (A resin) in a mold having a stamper. It is composed of an aluminum reflective film 5 formed and a protection J146 formed on the reflective crotch by an acrylic resin subne coat.

The printed portion 2 is formed as a multicolor printed portion using hard 1' of acrylic ultraviolet curable ink. This acrylic ultraviolet curable ink is polynistate acrylate 1.
-One hour of resin ink is used. This ink is applied to the disc ff1 by offset printing using a waterless lithographic plate (printing plate).
1 protective layer 6''-. An enlarged cross-sectional view of the waterless planographic plate is shown in FIG. As is clear from this drawing, the waterless planographic plate 7 is composed of a substrate 8, a primer layer 9, a photosensitive layer 110, and a silicone rubber layer 11. The upper surface 12 of the layer becomes a non-image area because it repels ink, and the approximately 2 μm recess 13 without the silicone rubber layer serves as an image area where the ink is received. Therefore, the ink 14 will adhere 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 ultraviolet irradiation.
Forms a hardened thin film. This offset printing 11 operation is performed for each color of ink to print in multiple colors.

FIG. 3 is a plan view of an offset printing device that prints in five colors. This printing apparatus includes a rotary table 15, which intermittently positions disks ml each having two protective layers 6 at ten positions. This rotary table is divided into 10 positions in the circumferential direction, each having a substantially circumferential support frame 16 and a pedestal 1 that slides on this support frame.
In the first station (2), the disk disks 1 stacked on the rotary supply table 18 are sucked by the supply handler 19 and supplied to the pedestal 17'-. At the 2.4.5.7 F3 Yohi 8 station ■■■■■, acrylic ultraviolet curing ink of different colors is sequentially applied onto the disk 1.

No. 3.6 and 9 stations (O) are ultraviolet irradiation stations. In the tenth station [phase], the disk disk 1 that has undergone offset printing is suctioned by a discharge handler 20 and discharged onto a rotating discharge table 21 .

The 2.4.5.7.8 stations for applying ink are, as shown in FIG.
Install roller 23, ink supply roller 24, 25.
26, 27, rollers 28, 29 and an ink tank 30 are provided to adjust the amount of ink supplied and eliminate uneven supply.

At each station of ink application, the ink 14 accumulated in the recessed portion 13 of the printing plate 7 is transferred onto the disk plate 1 onto the pedestal 17 via the blanket roller 22. During this transfer, the pedestal 17 slides on the support frame 16, and the ink is transferred to the disk 1 in a flat state.

The disk disk 1 co-fed to the first station (2) by the one-co-feed handler 19 is sent to the second station (2) by the rotation of the rotary table 15, where white ink is transferred. Subsequently, the white ink is rotated by the rotary table 15 and sent to the third station (3), where it is irradiated with ultraviolet rays to cure the white ink. Thereafter, in the same manner, black ink is transferred to the 11th station ■, and dark blue ink is transferred to the disk 1 at the fifth station ■, and the black ink and dark blue ink are irradiated with ultraviolet light at the sixth station ■. harden. At the 7th station ■, the yellow ink is transferred onto the disc 1, and at the 8th station ■, the yellow ink is transferred onto the disk 1, and at the 9th station ■, ultraviolet rays are irradiated to harden the brown ink and the yellow link. . Subsequently, the disk disk 1 sent to the 10th station (3) is ejected onto a rotating ejection table 21 by an ejection handler 20.

Therefore, acrylic UV-curable ink has a higher viscosity than acrylic solvent ink used for silk printing, and it also has a higher viscosity than the acrylic solvent ink used for silk printing. 2-4μ depending on irradiation
In contrast, in silk printing, a cured thin film of 10 m is formed by curing by ultraviolet irradiation or heat application.
The film thickness is ~20 μm, which is relatively thick compared to the film that forms multicolor printing areas by curing acrylic ultraviolet curable ink. Therefore, multicolor printing is difficult with silk printing, and ink Combined with its viscosity, it becomes difficult to express delicate patterns.

Next, the polycarbonate resin that is the material of the transparent substrate 4 of the disc 1 is made of a polycarbonate resin with a molecular weight lower than that of ordinary polycarbonate resin, which has a molecular weight of 40,000 to 50,000, in order to improve fluidity during injection molding. About 50,000 of them are in use. Therefore, the strength against stress is relatively reduced. Since this resistance can also be achieved by ultraviolet irradiation, it is desirable not to reduce the number of ultraviolet rays irradiated for curing the acrylic ultraviolet curable ink.

Therefore, in the embodiment, two color inks are simultaneously cured at the sixth and ninth stations (■).

In this case, it is desirable that the amount of ink of each color is small and that the hues of the two inks are similar. If this requirement is not met, it becomes possible to simultaneously cure inks of three or more colors.

(G) Effects of the Invention Since the present invention forms a multicolor printed area by curing acrylic ultraviolet curable ink, it is possible to provide an optical disc that expresses a delicate pattern on the disc protection JA. Can be done.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a partial sectional view of an optical disk, FIG. 2 is a partial sectional view of a waterless planographic plate, and FIG. 3 is a plan view of an offset printing device. No. 41A is a cross-sectional view of the ink application stay roller in the printing apparatus. 1...Disk board, 2...Printed section, 3...Recording surface,
4... Transparent substrate, 5... Reflective film, 6... Protective layer.

Claims (1)

[Claims] (1) In an optical disc consisting of a disc disc in which a reflective film and a protective layer are sequentially formed on a recording surface formed on one side of a transparent substrate, and a printing part formed on the protective layer, an acrylic ultraviolet curable ink is used. An optical disc formed by forming a multicolor printed part by curing.