JPH10172185A - Disk shaped recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the uniformly and constant high-speed rotation of a disk shaped recording medium by forming a label display surface with the upper half part printed by colored ink and with the lower half part printed by transparent ink and using colored and transparent ink whose weights per unit area are almost equal to prevent the generation of uneven centroid due to the distribution of ink weights of the label display surface. SOLUTION: On the first surface 1 of an optical compact disk A on which characters, illustration graphics and photographies are coated by printing, a first area 1a where characters, illustration graphics and photographies or the like are printed by colored ink is formed only on the roughly half of the upper side. Moreover, a second area 1b where is printed by transparent ink is formed on the remaining roughly half of the lower side to achieve the purpose of a label surface. At this time, dead weights of ink are dispersed on the whole of the label surface of the disk A uniformly to prevent the generation of uneven centroid due to ink weights by using colored and transparent ink whose weights per unit area are roughly equal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a disk-shaped recording medium, and more particularly, to a label display surface of the disk-shaped recording medium.

[0002]

2. Description of the Related Art Disc-shaped recording media such as optical compact discs, magneto-optical discs, laser discs, and write-once optical discs have a signal dedicated to recording / reproduction or reproduction on one surface and a disc-shaped signal on the other surface. A so-called label has been formed by screen printing, offset printing, or pasting a printing seal for the purpose of identifying a recording medium or having a design property. The label for the purpose of discriminating the disc-shaped recording medium or imparting a design property is sometimes not the entire surface of the disc-shaped recording medium but, for example, about half (about 1
There is a disk-shaped recording medium on which a label is printed only on the side of (2) or about ／.

[0003] The reading speed of signals (data) is as follows:
The speed has been increased every day, and the speed is quadruple (disk rotation speed: about 20
00-800 rpm), 8x speed (disk rotation speed: about 4
In addition, a disk player of 16 times speed (disk rotation speed: about 8000 to 3200 rpm) is sold as well as 000 to 1600 rpm. These high-speed disk players enable high-speed reading, and disk-shaped recording media are becoming more and more popular as storage (recording) media for personal computers.

[0004] One of the disk-shaped recording media, for example, the pits of an optical compact disk are formed on the disk surface by about 5 billion pits, and the pit size is about 1 µm.
The track interval is a very small size of about 1.6 μm, and it is necessary to trace these pits with a laser spot. This tracing is performed by controlling the optical head by a servo mechanism.

[0005]

However, in a disk-shaped recording medium in which the center of gravity of the disk-shaped recording medium is displaced from the rotation center of the recording medium and has a so-called eccentric center, the track radially fluctuates greatly. Further, when a high-speed disc player called a so-called 8 × speed or 16 × speed reproduces a signal, the fluctuation is further increased. For this reason, there is a problem that accurate reading of a signal cannot be performed in reproducing a disk-shaped recording medium having an eccentricity with a high-speed disk player.

[0006] This is because, when the radial variation of the track is severely caused by the eccentricity of the disk-shaped recording medium, the optical head traces the pits beyond the control range of the servo mechanism for controlling the optical head. This is because it may not be possible to read a signal (bit).

One of the reasons for the occurrence of the eccentricity is the weight of the ink for label printing, and the label printing is performed not on the entire surface of the disk-shaped recording medium but, for example, about half (1/2).
In the case of a disc-shaped recording medium on which a label is printed only on one side or about two-thirds of the side, the weight of the printing ink is biased.
There is a problem that an eccentricity occurs.

[0008]

According to the present invention, a label display surface of a disk-shaped recording medium has a first area in which images, characters, symbols, and the like are formed by colored ink, and a transparent ink. And a second area.

In the present invention, the weight per unit area of the transparent ink is equal to the average weight per unit area of the colored ink in the first region.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An optical compact disk which is one of disk-shaped recording media according to an embodiment of the present invention will be described with reference to the drawings. As shown in FIG.
Optical compact disk A has a disk outer diameter of 120.
mm, disk hole diameter: 15 mm, disk thickness: 1.2
mm, the substrate material is polycarbonate resin.

The characteristics of the optical compact disk A are high in recording density and excellent in large capacity (about 640 MB) random access. Inexpensive attachment / detachment / replacement operation with low price per bit is easy. It is easy to duplicate and highly productive. Non-contact recording / reproduction.
Resistant to dust and dirt on the surface. The recording data can be stored for a long period of time, and is rapidly spreading as an external recording medium of a personal computer in addition to a music recording medium.

As shown in FIG. 2, for example, an optical compact disc A as an external recording medium of a personal computer is provided on one first surface 1 for the purpose of discriminating the optical compact disc A, or for design. For example, characters, illustration figures, photographs, and the like for the purpose of providing the image are formed by printing, and on the other second surface 2, for example, computer game software or digital information signals such as images and characters are recorded.

For example, characters, illustrations, pictures, and the like formed by printing the first surface 1 indicate the contents of information recorded on the second surface 2. Depending on the display contents and display design, some optical compact discs A are printed on the entire surface of the disc, and some optical compact discs A are printed not on the entire surface but on only about half or about 2/3 of the surface Is given.

In the embodiment of the present invention, as shown in FIG. 1, a first surface 1 of an optical compact disk A on which characters, illustrations, pictures, and the like are applied by printing is placed above the first surface 1. The first area 1a in which characters, illustrations, pictures, and the like are printed by colored ink only in about half (about 1/2) of the first half, and the lower half (about 1
/ 2), a second area 1b printed with transparent ink is formed to achieve the purpose of the label surface.

At this time, the weight per unit area of the colored ink containing a dye for printing characters, illustrations, pictures and the like in the first area 1a and the transparent weight for printing the remaining second area 1b. The ink used is approximately the same as the weight per unit area of the ink. By using the inks whose weights per unit area are substantially equal, the first area 1a and the second area 1 of the first surface 1 are formed.
The respective weights of the inks applied to the optical compact disk A and b are evenly distributed over the entire surface of the label surface of the optical compact disk A, so that the optical compact disk A does not have an eccentricity due to the ink weight.

In this embodiment, the label is formed by printing. However, the present invention is not limited to this, and the label may be formed by using a colored seal and a transparent seal. Also,
Although the present embodiment has been described using the optical compact disc A, the present invention is not limited to this, and can be applied to all disc-shaped recording media such as a magneto-optical disc and a laser disc.

[0017]

According to the present invention, the label display surface of the disk-shaped recording medium has the first area in which images, characters, symbols, etc. are formed by colored ink, and the transparent ink. By having the second area, the center of gravity does not occur due to imbalance due to the distribution of ink weight on the label display surface of the disc-shaped recording medium, and uniform and stable rotation can be obtained even with a high-speed rotating player. Therefore, there is an effect that no signal reading error occurs.

[Brief description of the drawings]

FIG. 1 is a plan view showing an optical compact disk according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a main part of the optical compact disk of the present invention.

[Explanation of symbols]

 A Optical compact disk (disk-shaped recording medium) 1 First surface 1a First region 1b Second region 2 Second surface

Claims (2)

[Claims] 1. A label display surface of a disk-shaped recording medium,
A disk-shaped recording medium comprising a first area in which images, characters, symbols, and the like are formed by colored ink, and a second area in which transparent ink is formed. 2. The disk-shaped recording medium according to claim 1, wherein the weight per unit area of the transparent ink is equal to the average weight per unit area of the colored ink in the first area.