JP2003123324A - Optical recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To acquire scratch resistance required for securing recording/ reproducing characteristics which an optical recording medium itself originally has, when an image is printed on the surface of the optical recording medium by an ink jet system. SOLUTION: In the optical recording medium having at least a recording layer on a disk-like substrate, this optical recording medium has two or more layers including one layer to apply ink jet printing, where the image can be printed by the ink jet system, on the overcoat layer of the surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of recording / reproducing or rewriting information by irradiating a laser beam to change a material of a recording layer, and printing an image by an ink jet system. It relates to a possible optical recording medium.

[0002]

2. Description of the Related Art With the recent increase in the amount of information, a large amount of data can be recorded and reproduced at high density and at high speed.
The D-R / RW disc drive has been commercialized and is widely used. In recent years, in particular, the CD-R / RW disc drive has become relatively inexpensive compared to when it was first commercialized, and has been widely used by individual users. In addition, since the functionality of writing software for recording has been improved, an optical recording medium has come to be easily used as a recording medium for storing data by this disk drive. The optical recording medium is used for storing or editing audio software, computer software, image data, data such as documents,
It is used for backing up data in a computer or as a means of moving data.
(pactDisc Read Only Media)
As an information recording medium that is easily compatible with CD-R (Compact
Disc-recordable, rewritable, phase-change optical recording medium CD-RW (Compact D)
isc ReWritable) has been developed and has been widely used.

When storing, organizing, or distributing an optical recording medium on which the above information is recorded, the optical recording medium is normally identified by displaying the recorded content with a writing instrument that does not damage the label surface. To be able to do. Also,
A method is also used in which a label sticker having characters or images printed thereon is attached so that the information content in the optical recording medium can be known. Recently, by using an inkjet printer that has been widely used by personal computer users, an image can be directly printed on the surface of an optical recording medium by an inkjet method to create an original label surface for each user. Medium developed,
It has been put to practical use.

Various specifications have been disclosed so far for an optical recording medium capable of directly printing an image by an ink jet method. For example, in JP-A-8-161769, a light absorbing layer, a light reflecting layer, a protective layer and / or a print receiving layer are sequentially laminated on a transparent substrate, and the outermost protective layer or print receiving layer is a polyvinyl acetal resin and water. An optical recording medium characterized by containing a dispersible resin and / or a water-soluble resin is disclosed. According to this, since the outermost layer is not dissolved in the water-based or oil-based ink, the surface of the optical recording medium having good writability, printability, and peeling resistance can be obtained. Also, for example, Japanese Patent Laid-Open No. 8-3
In 29530, an optical recording medium in which a protective layer laminated on the reflective layer and which is also the outermost layer is a colored opaque layer, and in Japanese Patent Laid-Open No. 10-188344, a recording layer, a metal reflective layer, and a transparent substrate are provided. An optical recording medium comprising at least a protective layer printed in white and a hydrophilic surface layer containing a filler having a water-absorbing property and / or an oil-absorbing property, and in JP-A-11-110824, the background color of the protective layer surface. An optical recording medium in which the reflective layer to be formed of is a white metal film made of silver, aluminum, platinum, or an alloy thereof, and the thickness of the printed layer formed on the surface of the protective layer is 10 to 30 μm is used. It is disclosed. According to these known techniques, the range of hues reproduced in an image printed by an ink jet is widened, so that an optical recording medium surface on which an image with good resolution and color can be printed can be obtained. Further, for example, Japanese Patent Application Laid-Open No. 11-213445 discloses an optical recording medium in which the outermost layer of the protective layer is composed of a binder resin having a porous structure on the surface. According to the technique disclosed in the publication, image reproducibility in printing by an inkjet method, image bleeding in which ink does not bleed even in a high-humidity atmosphere or when water drops adhere, and glossiness when full-color printing is achieved An excellent optical recording medium surface can be obtained.

However, the effect of the technique disclosed in the above publication regarding the optical recording medium capable of printing an image by the ink jet method is as follows.
The overall image quality after printing, that is, only for the surface of the optical recording medium that can be printed by the inkjet method, and the effect on each characteristic of the optical recording medium itself such as mechanical characteristics, recording characteristics, and storage reliability. Has not been discussed. Among these characteristics, the scratch resistance of the optical recording medium is not limited to carrying the optical recording medium or writing information on the surface with a writing instrument, and the image printing is performed on the surface of the optical recording medium by an inkjet method. This is extremely important in consideration of troubles that may occur in the transportation system of the inkjet printer.

When an image is printed on the surface of an optical recording medium that can be printed by an inkjet printer, most inkjet printer mechanisms move the optical recording medium at a fixed speed in a straight line direction, and at the same time, Ink particles dripped from the ink cartridge that travels back and forth on a unique straight line on the path through which the optical recording medium passes.
An image is formed by being dispersed. The optical recording medium is usually fixed to a tray and moved by being transported together with the tray in order to prevent the image to be printed from being displaced or disturbed by the operation of the optical recording medium itself during inkjet printing. In an inkjet printer capable of supporting an optical recording medium, the method of transporting the optical recording medium by this tray is a method in which a tray used in many CD-R / RW disc drives is operated by a gear, or There is a method in which the disk is installed in advance on a flat adapter with a recess equivalent to the disk shape, and the adapter is inserted horizontally from the manual feed tray.

However, this latter type of manual feed tray is liable to cause problems during transportation. For example, the conveyance of the flat adapter in the inkjet printer is performed by using a plurality of rollers in the printer in the same manner as the conveyance of the paper when printing an image on the paper. In particular, in the vicinity of the ink cartridge where the ink particles are dropped, most of the printers have a plurality of transport rollers arranged in a straight line so as to go straight to a path through which an adapter including an optical recording medium passes. The transport roller contacts the adapter from above and below and rotates by applying pressure to transport the adapter, so the roller on the top naturally contacts the optical recording medium installed on the adapter. For this reason, the optical recording medium may move while being scratched on the surface when a small amount of dust adheres to the conveying roller or when the ink jet particles adhere and solidify and remain. Further, depending on the type of inkjet printer, the flat adapter may be made of cardboard or other thick paper. When the planar adapter made of this cardboard moves in the inkjet printer, it is warped upward due to the pressure from the transport roller. Due to this warp, the disc installed in the recessed portion on the adapter having the same shape as that of the disc floats and comes into contact with the transport roller and the tip of the ink cartridge. In some cases, the disc may dislodge from the planar adapter and remain in the inkjet printer, scratching the surface by operating mechanisms within the printer. Due to the above factors, when not only the protective layer of the disc but also the reflective layer and the recording layer are damaged, the recording / reproducing characteristics of the disc itself are affected.

[0008]

SUMMARY OF THE INVENTION Therefore, when the optical recording medium is an optical recording medium capable of printing an image on its surface by an ink jet method, the original optical recording medium itself is provided. The purpose is to acquire the scratch resistance required to secure the recording / playback characteristics of the.

[0009]

In order to solve the above-mentioned problems, (1) of the present invention, "in an optical recording medium having at least a recording layer on a disk-shaped substrate, an image is printed on the surface overcoat layer by an ink jet method. An optical recording medium having a laminate of two or more layers including one ink-jet printable layer capable of forming an ink-jet recording layer, (2) "imaging an image by an ink-jet method in which an overcoat layer and an uppermost layer are laminated. The optical recording medium according to the item (1), characterized in that one or more layers are provided between the ink-jet printable layers which can be formed, and (3) "two layers on the surface overcoat layer". The total film thickness of the existing layers is 1
It is achieved by the optical recording medium according to item (1) or (2), which is 3 μm or more and 60 μm or less.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Specific means of the present invention will be described below. An example of the form of the optical recording medium in the present invention is shown in FIG. The basic structure is such that a first protective layer (2), a phase change recording layer (3), and a substrate (1) having guide grooves are provided.
It has a second protective layer (4), a reflective heat dissipation layer (5), and an overcoat layer (6). Further, the intermediate layer (7) and the inkjet printing layer (8) are provided on the overcoat layer.

The substrate material is preferably a polycarbonate resin, which is excellent in moldability, optical characteristics and cost. In addition, for application to an optical recording medium (CD-RW) having a phase change recording layer, the width of the guide groove (groove) formed on the substrate used is 0.30 to 0.60 μm, and the depth of the guide groove is Two
It is desirable to set it to 00 to 550Å. The thickness of the substrate is not particularly limited, but 1.2 mm is preferable.

As the recording layer, Ag, In, Sb, Te
A material containing a quaternary phase-change recording material containing as a main component is suitable because the recording (amorphization) sensitivity / speed, the erasing (crystallization) sensitivity / speed, and the erasing ratio are extremely good. Further, in order to satisfy the reproduction stability of the signal and the life of the signal comprehensively, Ga, Zn, Sn, and S are added to the recording layer.
i, Pb, Co, Cr, Cu, Ge, Au, Pd, P
t, S, Se, Ta, Nb, V, Bi, Zr, Ti, A
It is effective to add at least one element selected from 1, Mn, Mo, Rh, C, N and O.
This is because the crystallization of the amorphous mark can be suppressed by adding at least one element selected from the above elements to the recording layer, and the reproduction stability of the signal and the life of the signal can be improved. Because you can. The mechanism is not clear, but these elements enter AgGnSbTe's spatial gaps or form chemical bonds, and
It is considered to be an additive that forms a compound or alloy with SbTe and suppresses crystallization of amorphous marks. So C,
Elements such as N, O, Si, Sn, and Ge having a small atomic radius, a large chemical bonding force with AgInSbTe, and a large number of chemical bonds are effective. The thickness of the recording layer is preferably 12 to 30 nm in consideration of initial characteristics such as jitter and mass production efficiency. It is preferable to form such a recording layer by a sputtering method which is excellent in mass productivity and film quality.

The above-mentioned recording layer material is described as a phase change type which uses an inorganic substance mainly made of metal, but the present invention is a write-once type recording layer mainly made of an organic substance made of an organic dye. It can also be applied to an optical recording medium using a material.

Materials for the first dielectric layer and the second dielectric layer include SiO, SiO ₂ , ZnO, SnO ₂ and Al _2.
Metal oxides such as O ₃ , TiO ₂ , In ₂ O ₃ , MgO and ZrO ₂ , Si ₃ N ₄ , AlN, TiN, BN and Zr.
Nitride such as N, ZnS, In ₂ S ₃ , TaS ₄ such as sulfide, SiC, TaC, B ₄ C, WC, TiC, Zr
Carbides such as C, diamond-like carbon, or a mixture thereof can be mentioned. For film formation, the sputtering method is preferable because it is excellent in mass productivity and film quality as in the recording layer. Since the film thickness of the first dielectric layer has a great influence on the reflectance, in order to satisfy the reflectance of 0.15 to 0.25 which is the standard of the CD-RW disc at the reproduction wavelengths of 780 nm and 650 nm, It is preferable that the dielectric layer has a thickness of 65 to 130 nm. The film thickness of the second dielectric layer is heat resistance,
20-40 nm from the viewpoint of sensitivity and repetitive recording performance
Is preferred.

Al, Au, Ag, and C are used as the reflective heat dissipation layer.
Metal materials such as u, Ta, Ti, and W, or alloys thereof can be used, and C is added as an additive element.
r, Ti, Si, Cu, Ag, Pd, Ta or the like is used. Such a reflection and heat dissipation layer includes the recording layer and the first layer.
-Similar to the second dielectric layer, it can be formed by the sputtering method, and the film thickness is preferably 100 to 160 nm.

It is desirable to have an overcoat layer on the reflection / heat dissipation layer as an antioxidant. An ultraviolet curable resin produced by spin coating is generally used as the overcoat layer, and the thickness thereof is preferably 3 to 15 μm from the viewpoint of preventing excessive errors and mechanical properties. Similarly to the overcoat layer, the hard coat layer is generally an ultraviolet curable resin prepared by spin coating, and its thickness is preferably 2 to 6 μm from the viewpoint of scratch resistance and mechanical properties. It is also effective to mix an electrically conductive material as necessary to prevent static electricity and prevent dust and the like from adhering.

In the optical recording medium having the above layer structure, a design label or a solid color layer is laminated on the overcoat layer, if necessary. For laminating on the overcoat layer, various known vapor deposition methods such as a sputtering method, an ion plating method and a plasma CVD method, or various coating methods such as spin coating, spray coating and dip coating are used. Lamination can be performed. Among them, a general method is coating by a screen printing method, which is suitable because the laminating step becomes simple. The coating layer laminated by the screen printing method,
It is preferable to use an ultraviolet curable resin because of the production efficiency of the process. It is desirable that the material of the coating layer used for the uppermost ink-jet layer be a quick-drying material that absorbs and fixes the ink dots that are dropped during image printing, and suppresses bleeding, especially for inkjet printers. Most of the inks used are anions, so organic and inorganic fillers containing cations are suitable.

In the optical recording medium capable of performing image printing by the ink jet system of the present invention, two or more layers are laminated on the overcoat layer, including one ink jet print layer capable of image printing by the ink jet system. It was effective to do. In addition, between the overcoat layer and the inkjet print layer that is applied on top,
It has been found suitable to have one or more additional stacks. As described above, the coating layer material used for the ink-jet layer is required to absorb and fix the ink droplets that are dripped during image printing, and to dry quickly. The material contains particles having a graininess of about 10 μm to the extent that graininess is felt when exposed. Therefore, when the layer to be laminated on the overcoat layer is only one layer to be inkjetted, the layer to be inkjetted is directly laminated on the overcoat layer, and therefore printing conditions at the time of screen printing, for example, squeegee hardness. Depending on the pressure or pressure, the pressure from the particles in the coating material affects the recording layer or the reflective layer laminated under the overcoat layer, and the defect rate of the optical recording medium increases. In addition, when the laminated ink-jet layer is thin, the surface strength is almost the same as before the lamination, and the scratch resistance of the optical recording medium is not improved.
Although it is not directly related to the characteristics of the optical recording medium itself,
Considering that an image is printed on the surface of the optical recording medium by an inkjet method, it may be difficult to stack the coating layer material depending on the combination with the ultraviolet curable resin used for the overcoat layer. It will not be used for printing. Alternatively, when the overcoat layer is transparent, the underlying color of the ink-jet layer is a metal color reflected by the reflective layer or the metal protective layer, so that the hue of the printed image cannot be sufficiently reproduced. Even if an opaque color where the reflective layer or the metal protective layer can reproduce the hue of the printed image, especially a white metal film is used, impurities remain in the chamber after the reflective layer or the metal protective layer is laminated by the sputtering method. Therefore, it takes time for preparation such as cleaning and pre-sputtering performed until another optical recording medium is manufactured by using another target, and the production efficiency of the subsequent optical recording medium decreases. Therefore, it is effective to stack two or more layers on the overcoat layer, including one inkjet-printed layer capable of performing image printing by an inkjet method.

Further, if the ink-jet printing layer is not present in the uppermost layer, the application of image printing by the ink-jet method on the optical recording medium cannot be achieved. Therefore, the position of two or more layers to be applied is such that the inkjet layer is at the uppermost layer, and there is one or more different laminated layers between the overcoat layer and the inkjet printed layer to be applied on the uppermost layer. There must be. Any number of layers may be applied between the ink-jet layer and the overcoat layer as long as it is one or more layers. Among these intermediate layers, the layer in contact with the overcoat layer is the defect rate of the optical recording medium. It is necessary to consider printing conditions such as squeegee hardness and pressure at the time of screen printing to prevent the increase of the temperature, and it is important that the layer in contact with the lower part of the inkjet target layer is a combination of materials that can sufficiently fix the inkjet target layer. . Although it is not a characteristic of the optical recording medium itself, the layer in contact with the lower layer of the inkjet target layer is an underlayer of the inkjet target layer, so an opaque color so that the hue of the printed image can be sufficiently reproduced,
It is preferable to use an ultraviolet curable resin that produces a white color. The UV curable resin laminated on the overcoat layer cures and contracts each coating layer by UV irradiation, and depending on the amount of contraction, it may affect the mechanical properties of the optical recording medium. It may be adjusted by considering the amount of warpage of the molded substrate, including the effect at the time of formation.

Further, if the total film thickness of two or more layers existing on the surface overcoat layer is 15 μm or more, sufficient scratch resistance can be obtained. 15μ
In the case of m or less, when the surface is scratched by a certain weight, the reflective layer, the metal protective layer, and the recording layer laminated below the overcoat layer are damaged, so that a plurality of regions having different signal recording qualities are formed. Occur. For example, for errors that can be corrected, the error rate average value rises over a certain period of time, and in some cases the recorded information cannot be reproduced. However, even if the total film thickness of two or more layers present on the surface overcoat layer is 15 μm or more, if it exceeds 60 μm, contact with the inside of the recording / reproducing system drive of the optical recording medium occurs, In particular, during recording / reproduction at high linear velocity, film peeling of the inkjet print layer may occur. Further, the influence on the mechanical properties of the optical recording medium is usually caused by the water absorbed / released by the substrate. However, in the lamination of two or more layers, most of the film thickness is the uppermost inkjet print layer. When occupying, the uppermost layer absorbs a large amount of water under high temperature and humidity, similar to the case of absorbing the ink dropped from the ink cartridge. Therefore, the influence of the uppermost layer material on the mechanical properties cannot be ignored, and it becomes difficult to design the warp amount of the optical recording medium. Therefore, the total film thickness of two or more layers existing on the overcoat layer on the surface of the optical recording medium is 13
It was effective that the thickness was not less than μm and not more than 60 μm. More preferably, the total film thickness of two or more layers present on the overcoat layer on the surface of the optical recording medium is 15 μm or more and 35 μm or more.
It is the following.

[0021]

EXAMPLES The present invention will be described below with reference to examples. However, the following examples do not limit the present invention in any way. The phase change type optical recording medium used for the optical disk capable of printing the image on the surface by the ink jet method has a guide groove with a width of 0.5 μm and a depth of 35 nm of 1.2 mm
Mold a thick polycarbonate substrate and place the first on this substrate.
The protective layer, the recording layer, the second protective layer, and the reflection / heat dissipation layer were sequentially laminated by the sputtering method. ZnSSiO ₂ was used for the first protective layer and the second protective layer, the film thicknesses were 90 nm and 30 nm, respectively, and the composition of the recording layer was Ag _4.0.
In _6.0 Sb _61.0 Te _29.0 , film thickness 18 nm
And Aluminum alloy is used for the reflective heat dissipation layer, and substrate / ZnSSiO ₂ (90 nm) / AgInSbTe
A layer structure of (18 nm) / ZnSSiO ₂ (30 nm) / Al alloy (140 nm) was formed. Further, an overcoat and a hard coat were formed by spin coating of an ultraviolet curable resin. This phase change type optical recording medium was subjected to a crystallization treatment on the entire surface of the recording layer of the optical recording medium by an initialization device having a large diameter LD.

After leaving the completed phase-change optical recording medium at a temperature of 25 ° C./humidity of 50% for 24 hours or more, the formed overcoat layer is provided with a layer to be a base of an ink-jet printing layer and The inkjet printing layers were sequentially laminated. That is, the number of intermediate layers between the inkjet print layer and the overcoat layer was set to one. These two
The layers were laminated by applying an ultraviolet curable resin as a layer material by screen printing and irradiating with ultraviolet rays.
The layer structure of the optical recording medium thus formed is shown in FIG. 1 as a schematic diagram. By using a white UV curable resin on the overcoat layer, that is, as a layer which is a base of the ink-jet printing layer, it is possible to reproduce the hue of the ink-jet printing image in a wide area. A milky white UV curable resin was used for the uppermost inkjet print layer. The total film thickness of the two laminated layers of the optical recording media used in Examples and Comparative Examples is as shown in Table 1, so that the film thickness of each of the two layers is the same, that is, half the total film thickness. I chose

[0023]

[Table 1]

On the phase change type optical recording medium which can be printed by the above ink jet system, the entire surface was recorded with a recording pulse waveform as shown in FIG. Recording linear velocity is 4.8
m / s, a low level pulse of a power level b and a high level pulse of a power level c having a time width of T in total are alternately output, and a total of (n−n ′) times are consecutive at a duty ratio y. The duty ratio of the pulse part mp was set to 0.625. The optical recording / reproducing apparatus used for the recording has the circuit and driving unit shown in FIG. 3, a pickup having a wavelength of 780 nm and an NA of 0.5.

After that, the inkjet print layer on the surface of the optical recording medium was ground by using a device having the driving unit shown in FIG. 4 and having a base that slides in the horizontal straight line direction. Grinding fixes the optical recording medium on a slide table,
Align the needle-shaped diamond object to the starting point of the radial position to grind the inkjet printed layer of the optical recording medium,
The slide table including the optical recording medium was moved from the inner circumference to the outer circumference in a straight line at a speed of 1 mm per second. As shown in Table 2, grinding of the optical recording medium was performed while increasing the weight of the needle-shaped object at each radial position. At the same time, an unground portion of 1 to 2 mm was provided between the respective grinding positions. As a result, an optical recording medium having seven ground portions was produced.

[0026]

[Table 2]

The recording signal of the optical recording medium is recorded by the optical recording / reproducing apparatus shown in FIG. 3 at a linear velocity of 1 before and after grinding.
The entire surface was reproduced at 2 m / s, and the changes in the C1 error rate of the optical recording media of Examples and Comparative Examples with respect to each weight before and after grinding were examined, and the results are shown in FIGS. According to this, the total film thickness of the two laminated layers is 7.5.
In the case of Comparative Example 2 in which the thickness is μm, C at the grinding point with a weight of 30 g
1 There is no place where the error rate becomes 0 (FIG. 8), and this is almost the same as Comparative Example 1 (FIG. 7) in which the total film thickness is 0, that is, two layers are laminated on the phase change optical recording medium. It was a trend. Further, as in Comparative Examples 3 and 4, when the total film thickness of the two laminated layers increased, the grinding point where the C1 error rate became 0 was shifted to a heavier weighted point (Comparative Example 3: FIG. 9, Comparative Example). Example 4: FIG. 10), and when the total film thickness is 15 μm or more (Examples 1 and 2), 70 g
No increase in the C1 error rate was observed even when grinding was performed with the weight of 1., and the C1 error rate was equivalent to that before grinding (Example 1: FIG. 1, Example 2: FIG. 2), and these showed high scratch resistance. It was

Further, the total film thickness of the laminated layers is from 15 μm to 5 μm.
Similarly, optical recording media sequentially increased in increments of m were produced, and under the high-temperature and high-humidity environment of temperature 35 ° C./humidity 85%, full recording (linear velocity 4.8 m / s) and reproduction (linear velocity 12 m) / S) results in a total film thickness of 65 μm
In the above optical recording medium, during reproduction, the inner layer of the optical recording apparatus was brought into contact with the inner layer of the printable layer and the intermediate layer of the printable layer and the overcoat layer, and film peeling occurred.

[0029]

As is apparent from the detailed and specific description above, according to the present invention, in the optical recording medium capable of printing an image on the surface by the ink jet method, the original optical recording medium itself is obtained. It has an extremely excellent effect that the scratch resistance required to secure the recording / reproducing characteristics of the can be acquired.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing a configuration example of an optical recording medium according to the present invention.

FIG. 2 is a diagram showing an embodiment of a recording pulse waveform of an optical recording medium according to the present invention.

FIG. 3 is a diagram showing an embodiment of recording and reproduction in the present invention.

FIG. 4 is a diagram showing an embodiment of the inkjet print layer grinding of the optical recording medium according to the present invention.

5 is a first example of the present invention (total laminated film thickness: 15 μ)
It is a figure which shows the mode of change of C1 error rate before and behind the inkjet printing layer grinding of the optical recording medium of m).

FIG. 6 is a second example of the present invention (total laminated film thickness: 17.
FIG. 5 is a diagram showing how the C1 error rate changes before and after grinding of the inkjet print layer of an optical recording medium of 5 μm).

FIG. 7 is a comparative example 1 of the present invention (total laminated film thickness 0 μ).
FIG. 3 is a diagram showing how the C1 error rate changes before and after grinding of the inkjet print layer of the optical recording medium (m, the uppermost layer is an overcoat layer).

FIG. 8 is a comparative example 2 of the present invention (total film thickness of 7.5).
FIG. 6 is a diagram showing a change in C1 error rate before and after grinding of the inkjet print layer of the optical recording medium of (μm).

FIG. 9 is a comparative example 3 of the present invention (total film thickness of 10 μm).
It is a figure which shows the mode of change of C1 error rate before and behind the inkjet printing layer grinding of the optical recording medium of m).

FIG. 10 is a comparative example 4 of the present invention (total laminated film thickness: 1).
FIG. 9 is a diagram showing how the C1 error rate changes before and after grinding the inkjet print layer of an optical recording medium of 2.5 μm).

[Explanation of symbols]

1 substrate 2 First protective layer 3 recording layers 4 Second protective layer 5 Reflective heat dissipation layer 6 Overcoat layer 7 Middle class 8 Inkjet print layer 9 Hard coat layer

Claims (3)

[Claims] 1. An optical recording medium having at least a recording layer on a disk-shaped substrate, comprising two or more layers including one inkjet-printed layer capable of performing image printing on the surface overcoat layer by an inkjet method. An optical recording medium having a laminate. 2. The one or more layers are provided between the overcoat layer and the ink jet printing layer capable of image printing by the ink jet method laminated on the uppermost layer. The optical recording medium described. 3. The optical recording medium according to claim 1 or 2, wherein the total film thickness of a laminate having two or more layers on the surface overcoat layer is 13 μm or more and 60 μm or less.