JPH02209290A - Optical recording material - Google Patents

Abstract

PURPOSE:To obtain recording having a contrast sufficient to read by the naked eye using low output laser beam by specifying the reflectivity at the main wavelength of recording laser beam on the surface of an optical recording material wherein a thermal color forming layer and a beam absorbing layer containing a near infrared absorbent are laminated to a base material. CONSTITUTION:A thermal color forming layer containing a basic dye and an org. coupler and a beam absorbing layer containing a near infrared absorbent are laminated to a base material to form a recording material performing recording by laser beam having a main wavelength in the vicinity of a near infrared region and the reflectivity at the main wavelength of laser beam on the surface of the recording material is adjusted so as to become 15-80%. There is no special limit in the order of lamination and the order of base material/thermal color forming layer/beam absorbing layer and the order of base material/beam absorbing layer/thermal color forming layer may be employed. A protective layer for reducing the effect from the outside may be provided on the uppermost layer and, especially, it is pref. that the thermal color forming layer is the uppermost layer. When a hydrophilic material is used as the base material, as the near infrared absorbent, a water-soluble near infrared absorbent or a finely divided dispersible near infrared absorbent is pref. used and, especially, the use of the water-soluble near infrared absorbent is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical recording medium that performs recording by thermally converting irradiated laser light.

(Prior art) Among the direct recording methods that do not require development or fixing, thermal recording paper that uses basic dye and organic color developer as color formers is easy to operate and maintain, making it suitable for facsimiles and printers. Widely used.

However, this method cannot be used with thermal heads or heat-generating ICs.
Because the pen is brought into direct contact with thermal recording paper to heat and record, colored molten matter adheres to the thermal head and heat-generating IC pen, causing problems such as adhesion of residue and sticking.
There were problems with recording failures and recording quality.

Particularly in the case of continuous line drawing in the recording flow direction, such as with a plotter printer, it has been impossible to perform continuous printing without causing problems such as adhesion of residue.

Furthermore, in the recording method using a thermal head, it is considered difficult to increase the image resolution to 8 lines/mm or more.

Therefore, a non-contact recording method using light has been proposed as a method of eliminating problems such as adhesion of residue and sticking and further improving resolution.

JP-A No. 54-4142 discloses that in a heat-sensitive recording material in which a heat-sensitive recording layer containing leuco dye as a main component is coated on a support, a metal compound having lattice defects is used. It is disclosed that thermal recording is possible by absorbing light in the visible and infrared regions and converting it into heat.

JP-A-58-209594 discloses an optical recording medium in which at least one set of a near-infrared absorber and a heat-sensitive coloring material having an absorption wavelength in the near-infrared region of 0.8 to 2 μm are laminated on a substrate. JP-A-58-94494 discloses that one or more heat-sensitive coloring materials and one or more near-infrared compounds consisting of a compound having a maximum absorption wavelength in near-infrared light of 0.7 to 3 μm. The present invention discloses a recording medium formed by coating a base material with an external absorbent, and discloses that recording on these recording media can be performed using a hot plate and a laser beam having a wavelength around near infrared. ing.

(Problem to be Solved by the Invention) The above publication describes an optical recording medium whose base material is a non-hydrophilic material such as a plastic plate or film, and an optical recording medium whose base material is paper, which is a hydrophilic material. However, the conditions that an optical recording medium should maintain in relation to laser light in order to make it a practical optical recording medium have not been clarified.

Since optical discs are mechanically readable, it is sufficient to obtain optical contrast at the reading wavelength, whereas the recording medium of the present invention has a contrast that can be read with the naked eye because the recorded information can be directly read by humans with the naked eye. is required.

Furthermore, considering a general-purpose optical recording device that can be used for office processing and ordinary measurements, the output of the laser that can be used must be low. A small laser that can be used in such a device has a dominant wavelength in the vicinity of near infrared rays of 650 to 1500 mμ.

In view of this situation, it is an object of the present invention to provide an optical recording medium that can record images that can be directly read with the naked eye even with a low-power laser beam having a dominant wavelength in the near-infrared region. did.

(Means for Solving the Problem) The above problem is to create a heat-sensitive color forming layer containing a basic dye and an organic color developer on a base material, which is recorded using a laser beam having a main wavelength in the vicinity of near-infrared. The problem was solved by creating an optical recording medium in which a light absorption layer containing an infrared absorbing agent is laminated, and the reflectance of the surface of the recording medium at the dominant wavelength of the laser beam is 15 to 80%.

The present invention uses a laser with a dominant wavelength near the near-infrared region, and currently low-cost lasers that can be used in general-purpose recording systems have wavelengths of approximately 650 mμ to 1
It has a diameter of 500 mμ.

On the other hand, the organic near-infrared absorber of the present invention also has absorption in the vicinity of 700 to 900 mμ, regardless of whether it is water-soluble or not.
The coating layer is also clearly colored.

When an optically recorded image is drawn on optical recording paper by laser beam irradiation and read with the naked eye, there are several important differences from mechanical reading. That is, in the case of mechanical reading, this coloring is not a problem at all, whereas in the case of reading with the naked eye, there must be a certain level of contrast between the image and the background color that can be discerned with the naked eye. When we set practical constraints on contrast and light energy, we discovered that there is an essential region for the reflectance of the optical recording surface relative to the wavelength of the laser light.

The reflectance of the surface of the optical recording medium for the laser main wavelength is 15%
When the density is less than 1, light absorption is sufficient and the image density is sufficiently high, but the visual contrast with the ground color is small and it becomes difficult to read with the naked eye. In addition, if the reflectance of the surface of the optical recording medium with respect to the laser main wavelength exceeds 80%, the low-output semiconductor laser light will have weak light absorption and the amount of heat generated will be insufficient, resulting in either no image being recorded or no image being recorded. However, the density is extremely low, and the visual contrast with the ground color is small, making it difficult to read with the naked eye.

The optical recording medium of the present invention has a thermosensitive coloring layer and a light absorption layer laminated on a base material, but the order of lamination is not particularly limited. The order may be the base material, the light absorbing layer, and the thermosensitive coloring layer. Further, a protective layer may be provided on the top layer to reduce external influences, and particularly when the heat-sensitive coloring layer is the top layer, favorable results are brought about.

The light-absorbing layer provided under the heat-sensitive coloring layer is obtained by applying a paint consisting of a near-infrared absorber, a binder, and a white pigment onto a substrate. The white pigment efficiently reflects near-infrared light as well as visible light, and efficiently supplies near-infrared light to the near-infrared absorber surrounding the white pigment.

The light-absorbing layer provided on the heat-sensitive coloring layer needs to be transparent, so it is usually obtained by applying a paint consisting of a binder and a near-infrared absorber. Therefore, a preferred method is to incorporate a near-infrared absorber into a transparent protective layer so that the transparent protective layer functions as both a protective layer and a light absorbing layer.

A light absorption layer may be provided below the thermosensitive coloring layer, and a protective layer containing a near-infrared absorber may be provided above. In this case, coloring of the optical recording medium can be improved by dividing a predetermined amount of the near-infrared absorber into the lower layer and the upper layer.

The near-infrared absorber is not particularly limited, but if a hydrophilic material is used as the base material, it is preferable to use a water-soluble near-infrared absorber or a micronized dispersible near-infrared absorber. In particular, it is preferable to use water-soluble near-infrared absorbers.

As mentioned above, some optical recording media using near-infrared absorbers have been known, but there is no example of using a water-soluble near-infrared absorber among them.

Since one purpose of the present invention is to obtain an optical recording medium that can be directly handled by humans and whose records can be viewed, it is preferable that the handling thereof be safe. Water-soluble compounds do not accumulate, and in this respect, the use of water-soluble near-infrared absorbers is preferable from the viewpoint of safety. When using the hydrophilic group Murakami, the water-soluble near-infrared absorber can be made into a water-based paint, which is advantageous in production since conventional water-based paint coating equipment can be used as is. Furthermore, since the water-soluble near-infrared absorber is uniformly present in the paint, near-infrared light is absorbed uniformly everywhere, and a uniform image with good resolution can be obtained. Furthermore, water-soluble near-infrared absorbers have a large near-infrared absorbing power per unit weight, and can be used in a smaller amount than dispersible near-infrared absorbers. Even when the optical recording medium is used, the background color of the optical recording medium can be improved, and it is also economically advantageous.

The water-soluble near-infrared absorber in the present invention is one that can absorb near-infrared light and dissolve an amount of the near-infrared absorber that can release the amount of heat necessary to obtain the desired recording density. be. The amount cannot be determined unconditionally depending on the near-infrared absorption ability of the near-infrared absorber, the composition of the optical recording medium, or the relationship with the optical recording device such as the output of the laser beam, the degree of condensation, and the distance from the recording surface. According to experiments, if the solubility in water is 5% or more, it can often be used as a water-soluble near-infrared absorber. Preferably, the solubility in water is 10% or more. Therefore, the dispersible near-infrared absorber in the present invention does not satisfy the above conditions.

Dispersible near-infrared absorbers usually have poor absorption efficiency and heat conversion efficiency for near-infrared light, probably due to their large particle size (but when applied in sufficient amount to obtain the desired recording density, There is a tendency for the recording medium to be strongly colored and the contrast of the image to be impaired.Therefore, in the present invention, the dispersible near-infrared absorber is used in the form of fine particles.The finer the degree of atomization, the better. The present inventors have found that for practical purposes, the average particle size should be 3 μ or less.The particles are made fine by grinding with an attritor sand grinder or the like in a water-soluble binder.

The reason why a heat-sensitive coloring layer is provided on a base material and a protective layer containing a near-infrared absorber is provided on the heat-sensitive coloring layer is that the heat-sensitive coloring layer can be protected by the protective layer, and the unevenness of the support can be avoided. Since it is possible to equalize the thickness by the thermosensitive coloring layer and to make the thickness of the light-absorbing protective layer thereon uniform, the light-absorbing ability and heat-generating ability become uniform, and it is easy to obtain a uniform image density. For this purpose, a uniform protective layer can be obtained by making the light-absorbing material water-soluble or dispersed in fine particles. In particular, the use of a water-soluble light absorbing agent increases the light transmittance of the light absorbing layer, and the light absorption is performed throughout the entire layer of the light absorbing layer, resulting in high absorption efficiency.

The light absorption layer is obtained by coating a hydrophilic substrate with a paint consisting of a near-infrared absorber, a binder and, if necessary, a white pigment.

The near-infrared absorber may be one that has absorption in the near-infrared region of 0.7 to 3 mμ. 9449
In addition to cyanine dyes, thiol nickel complexes, and squarylium dyes disclosed in Publication No. 4, nitrone compounds and their metal complexes, and polymethine compounds in "Near-infrared absorption dyes" (Kagaku Kogyo 43, May 1986 issue). Pigment (
cyanine dyes), complexes of thiol and cobalt or palladium, phthalocyanine dyes, triallylmethane dyes, immonium or diimmonium dyes, naphthoquinone dyes, or 1,3-diphenylthiourea and the like discovered by the present inventors. 1. Thiourea derivatives such as 3-dibenzylthiourea and organic acid salts of metals with atoms ff 140 or more excluding Group IA and Group IA of the periodic table,
Patent application No. 6, filed by the present inventors, relating to an optical recording medium using a treatment product obtained by mixing and heat-treating Alcolade or hydroxide, or a dispersible near-infrared absorber.
It is a dispersible near-infrared absorber such as copper sulfide or graphite described in No. 3-272702. Further, the conventionally known cyanine dyes, thiol nickel complexes, triallylmethane dyes, etc. are near-infrared absorbers that dissolve in water or solvents, and specific examples thereof are also disclosed in Japanese Patent Application No. 1983- 2
No. 72702.

Examples of water-soluble near-infrared absorbers of the present invention include near-infrared absorbers 5116510, 5109564 manufactured by IC1,
Examples include, but are not limited to, the compounds shown below.

The heat-sensitive coloring layer is exactly the same as the coloring layer of heat-sensitive recording paper, which contains a known electron-donating colorless dye and an electron-accepting organic color developer as color-forming components, and is completely different from all the known coloring layers of heat-sensitive recording paper. technology can be applied. Basic colorless dyes are
Triphenylmethane type such as crystal violet lactone, fluoran type such as 3-diethylamino-6-methyl-7-anilinofluorane, 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2 −
azaphthalide series such as methylindol-3-yl)-4-azaphthalide, or 3,6゜6-tris(dimethylamino)spiro[fluorein-9,3-phthalide]
Leuco dyes such as fluorine dyes such as

Examples of organic color developers include bisphenol A, 4-hydroxybenzoic acid ester, 4-hydroxyphthalic acid diester, phthalic acid monoester, bis-(hydroxyphenyl)phenyls,
4-ruphides, 4-hydroxyphenylarylsulfones, 4-hydroxyphenylarylsulfonates, 1,3-di[2-(hydroxyphenyl)-2-propyl]-benzenes, 4-hydroxybenzoyloxybenzoic acid ester , bisphenol sulfones, etc.

Examples of the binder include completely saponified polyvinyl alcohol having a degree of polymerization of 200 to 1900, modified polyvinyl alcohol such as amide-modified polyvinyl alcohol, hydrobovine diethylcellulose, styrene-butadiene copolymer, and the like.

In addition, fatty acid amide, montan wax, etc. are used as sensitizers or quality control agents, and clay calcium carbonate,
Alternatively, fillers commonly used in the paper processing field, such as plastic pigments, can be added. In particular, hollow plastic pigments are preferred because they have good reflection of near-infrared light and good heat retention properties. The various materials used in these thermosensitive color forming layers include basic colorless dyes, organic color developers, binder sensitizers, fillers, and quality materials described in Japanese Patent Application No. 63-272702 filed by the present inventors. Modifiers can equally be used in the present invention.

The types and amounts of the organic color developer, basic colorless dye, binder, sensitizer, filler, and other various components in the color forming layer used in the present invention are determined according to the required performance and recording suitability, and in particular, Although not limited, usually 3 to 12 parts of organic color developer and 3 parts of sensitizer to 1 part of basic dye.
-12 parts, 1-20 parts of filler are used, and the binder is suitably 10-25 parts based on the total solid content of the coloring layer.

The organic color developer, basic colorless dye, and sensitizer are each individually or together with other materials added as necessary, and are reduced to a particle size of several microns or less using a grinding machine such as a ball mill, attritor sand grinder, or an appropriate emulsifying device. The mixture is atomized until it becomes granulated, then mixed, and a binder and, if necessary, the various quality control agents mentioned above are added to form a heat-sensitive coloring coating liquid.

The coating liquid is applied onto a substrate or a light absorption layer to form a heat-sensitive coloring layer. By laminating the thermosensitive coloring layer on the light absorption layer, the coloring of the optical recording layer is further hidden, resulting in an optical recording medium with a desirable appearance.

It is a preferable method to provide a protective layer on the surface of the thermosensitive coloring layer to reduce or prevent contamination from the external environment such as moisture, gas, water, solvent, oil, etc.

The protective layer is preferably one that is transparent to visible light and does not have an adverse effect on the thermosensitive coloring layer, and one or more binders are selected from among the binders normally used for the thermosensitive coloring layer. When a water-soluble near-infrared absorber is contained in the protective layer or between the protective layer and the thermosensitive coloring layer, the sensitivity of the destination recording medium is increased.

The optical recording medium obtained in this way emits a laser beam having a main wavelength near near infrared rays at a focal length of 0°5 to 50 mm.
By condensing and recording light using a group of two or more condensing lenses with a numerical aperture (NA) of 0.1 to 0.5, clear images with good contrast can be obtained using low-power laser light. .

Light sources necessary for optical recording on optical recording media include semiconductor lasers, diode bombing YAG lasers, He-Ne
These include gas lasers, dye lasers, etc., and in order to be used as an office recording device, a laser with a low output of about 5 to 100 mW is preferable from the viewpoint of device miniaturization, safety, cost, etc.

(Function) As described above, in an optical recording medium in which a thermosensitive coloring layer containing a basic dye and an organic color developer and a light absorption layer containing a near-infrared absorber are laminated, a recording laser on the surface of the recording medium is used. The mechanism by which an image that can be directly read with the naked eye is obtained by irradiating a recording laser beam on a recording surface whose reflectance at the optical dominant wavelength is adjusted to 15% to 85% is not clear, but the optical recording surface at the optical dominant wavelength is When the reflectance is less than 15%, the absorption at that wavelength is approximately 85% or more, so the image density is sufficiently high, but the macroscopic contrast is small in relation to the background color, and it is It becomes difficult to read. In addition, if the reflectance of the surface of the optical recording medium with respect to the laser main wavelength exceeds 80%, low-output laser light will have weak light absorption and the amount of heat generated will be insufficient, resulting in an image not being able to be recorded at all, or even if it can be recorded. The concentration is extremely low,
It is thought that the contrast with the naked eye is small due to the background color, making it difficult to read with the naked eye.

(Example) Next, an example of the present invention will be described. Parts and percentages in examples
are parts by weight and % by weight.

5 - Dye dispersion (Liquid A) and color developer dispersion (Liquid B) with the above and below compositions
were separately wet-ground for 1 hour using a sand grinder, and then 25 parts of silica was added to 6.3 parts of Part A and 25 parts of Part B.
% dispersion was mixed to obtain a heat-sensitive coloring coating liquid, and this coating liquid was coated and dried at 5 g/m using a Mayer bar on a high quality surface having a basis weight of 60 g/r to form a heat-sensitive coloring layer.

[Thermosensitive Coloring Layer] (A) Liquid: Dye dispersion Black coloring dye: OD8 2.0 parts 10% PVA aqueous solution 3.4 parts Water 1. 9th part O
DB: 3-diethylamino-6-methyl-7-anilinofluorane (B) solution: Color developer dispersion Color developer: BPA 6.0 parts Parabenzylbiphenyl 4. o part 10% PVA aqueous solution 12.5 parts water 2.5 parts BP
A: Bisphenol A Next, 6 parts of a near-infrared absorber aqueous solution (liquid C) and 105 parts of a protective layer solution (liquid D) of the following formulation were mixed, and using a Mayer bar, a solution containing a near-infrared absorber was mixed. A protective layer coating solution was applied onto the heat-sensitive coloring layer at a rate of 4 g/rd to obtain an optical recording sheet.

(C) Liquid: Near-infrared absorber aqueous solution Near-infrared absorber (rcIs116510) 10 parts 10% PVA aqueous solution 50 parts water
When 40 parts of each of these were added and mixed by stirring, a gray colored aqueous solution was obtained.

(D) Solution: Protective layer 10% PVA aqueous solution 100 parts Glyoxal (40%) 5 parts The optical recording paper thus prepared was coated with a semiconductor laser head (laser diode collimator head LDC-7820-C■Nc; abraid). Manufactured by Obtec, center wavelength 780 nm, output 2
The optical recording paper was irradiated with a laser beam and optically printed using the apparatus shown in FIG. 1, which combined a condenser lens with a numerical aperture of 0.28 (0 mW) and a condensing lens with a numerical aperture of 0.28. The irradiation time was 11,500 seconds.

The recorded image and ground color were measured as follows, and the results are shown in Table 1.
It was shown to.

The density of the recorded image (colored spot) was measured using a two-microdensitometer (PDM-5, manufactured by Konishiroku Photo Industry Co., Ltd.), and the measured value was converted into Macbeth density. Background color of optical recording paper: Measured with a Macbeth densitometer.

Actual 11 cases 23 The mixing ratio of the near-infrared absorber solution (liquid C) and the protective layer solution (liquid D) in Example 1 was changed so that the surface reflectance at 780 parts m was 30% and 40%. Optical recording paper was obtained and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Shishiki Takumi-1 The water-soluble near-infrared absorber of Example 1 was replaced with Kayasorb IR-750, which is a dispersible near-infrared absorber, and sanded until the average particle size became 2.5μ and 1.5μ. Wet-dispersed with a grinder, the surface reflectance at 780 parts m is 70
% and 80%, except for mixing with the protective layer solution.
Optical recording paper was obtained and evaluated in the same manner as in Example 1. The results are shown in Table 1.

Souritsuyu 1 OD combination of black dye and color developer used in heat-sensitive coloring layer
Optical recording paper was prepared and evaluated in the same manner as in Example 1, except that B/POB was used, and the results are shown in Table 1.

The structures of the black dye and developer are shown below.

Color developer: POB: p-hydroxybenzoic acid benzyl ester 1- The combination of black dye and color developer used in the heat-sensitive coloring layer is 0D.
The heat-sensitive coloring layer was the same as in Example 1 except that B-2/BPA was used, and the near-infrared absorber used in Example 1 was ICl5109.
A light absorbing layer was prepared on the thermosensitive coloring layer by mixing and coating 8 parts of the solution replaced with 564 and 105 parts of the protective layer solution to obtain an optical recording medium with a reflectance of 30% at 830 parts m. A semiconductor laser head (laser diode collimator head L) with a dominant wavelength of 830 nm was attached to the optical recording paper thus prepared.
Recording evaluation was performed under the conditions of Example 1, except that DC-8330-CINC (manufactured by Applied Oftech, output 30 mW) was used. The results are shown in Table 1.

0DB-2: Dibutylamino-6-methyl-7-anilinofluoran real 101 The combination of black dye and color developer used in the roasted heat-sensitive coloring layer is S-
2057BPA was used as in Example 1, and on top of this, the water-soluble near-infrared absorber in Example 1 was replaced with ICl5109564/2, which is a dispersible near-infrared absorber, and an average particle Wet dispersion with a sand grinder until the diameter is 1.5μ, and the surface reflectance at 830nm is 30%.
An optical recording paper was obtained in the same manner as in Example 1 except that it was mixed with the protective layer solution so that the following was obtained, and it was recorded and evaluated under the conditions of Example 7.

The results are shown in Table 1.

Black dye 2S-205: a-(N-ethyl-N-isoamyl)-6-methyl-7-anilite fluorane As is clear from Table 1, the surface reflection of the optical recording medium at the main wavelength of the recording laser beam is 15 ~80% of optical recording media must have a good balance between color density and background color and sufficient contrast to read the record with the naked eye, regardless of the type of thermosensitive coloring material or near-infrared absorber used. I understand.

2. Mix the near-infrared absorber solution (C) and the protective layer solution (D) used in Example 1 so that the reflectance of the completed optical recording medium at 780 nm is 90%. An optical recording medium was obtained and evaluated in the same manner as in Example 1, except for the following.

Salt 11-'' Same as Example 8 except that the near-infrared absorbent liquid used in Example 8 was blended into the protective layer solution so that the reflectance of the completed optical recording medium at 830 nm was 90%. An optical recording medium was obtained and evaluated.

5 - In Main Example 1, except that the near-infrared absorber solution (C) was not used, an optical recording medium was obtained in the same manner as in Example 1,
Records were evaluated in the same way.

From Table 1 showing the evaluation of Comparative Examples 1, 2, and 3, optical recording materials whose surface reflection at the recording laser main wavelength is less than 15% have extremely high color density as seen with a densitometer, but
The background color is also very dark and the contrast seen with the naked eye is poor, making it unusable for practical use.Furthermore, if the surface reflection of the optical recording medium exceeds 85% at the main wavelength of the recording laser, the background color is good, but the thermosensitive coloring layer cannot be used. It is clear that since it absorbs as little light as possible to emit enough heat to produce color, it cannot produce a record that can be discerned with the naked eye.

-11:2''- −j” [Kei− --"L-"L-1 DB DB-2 DB DB P.A. OB P.A. P.A. P.A. P.A. P.A. ICIS116510 <dissolution) Kayasorb IR-750 1cIsL1651Q (dissolved) ICIS109564 (dissolution) lcIs109564/2 ICIS116510 (melting) ICIS109564/2 Without using 2.5μ m, 5μ m.

1.5μ 30% (Effect of the invention) As explained above, a heat-sensitive coloring layer containing a basic dye and an organic color developer and a light absorption layer containing a near-infrared absorber are formed on a base material. By setting the reflectance of the surface of the laminated optical recording medium at the dominant wavelength of the recording laser beam to 15 to 80%, it is possible to obtain a record with sufficient contrast to be read with the naked eye using a low-power laser beam. In order to obtain this reflectance, by using a water-soluble near-infrared absorber or a finely divided dispersible infrared absorber, safety in use and ease of manufacture are improved, and practical light becomes possible. It has the effect of being able to be used as a recording medium.

[Brief explanation of the drawing]

Figure 1 is a block diagram of a laser beam recording device. 1... Laser diode collimator head, 2... Shutter 3... Condensing lens group, 4... Optical recording paper,
5...Power source 1 - Figure 1

Claims (3)

[Claims] (1) A light absorption layer containing a heat-sensitive coloring layer containing a basic dye and an organic color developer and a near-infrared absorber on a base material, which is recorded using a laser beam having a main wavelength near the near-infrared. 1. An optical recording medium comprising laminated layers, characterized in that the surface of the recording medium has a reflectance of 15 to 80% at the dominant wavelength of laser light. (2) The optical recording medium according to claim 1, wherein the near-infrared absorber is a water-soluble organic near-infrared absorber or a finely divided organic near-infrared absorber. (3) The optical recording medium according to claim 2, wherein the water-soluble near-infrared absorber has a solubility in water of 5% or more.