JPH09286183A - Dampening waterless planopraphic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a waterless planograph, which has favorable sensitivity and image reproducibility and can be writable with laser, by a method wherein recording layer containing metal and metal sulfide and a silicone rubber layer are laminated onto a support in the order named. SOLUTION: This dampening waterless original planographic printing plate is formed by laminating a recording layer containing a metal and a metal sulfide and a silicone rubber layer are laminated onto a support in the order named. As the metal in the recording layer, Mg, Sc, Y, Ti, Zr or the like singly, the combination of two or more of them or their alloy is employed. Further, as the metal sulfide in the recording layer, CrS, MoS2 , MnS, NiS, In2 S2 , GeSx or the like singly or in two or more is used. Furthermore, as the silicone rubber layer, crosslinked silicone rubber layer can preferably be used, especially film formed by hardening condensation type silicone or addition type silicone can be preferably used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate requiring no fountain solution (hereinafter referred to as "waterless planographic printing plate") capable of performing printing without using fountain solution by heat mode recording with a laser beam, particularly sensitivity and image. The present invention relates to a waterless lithographic plate with good reproducibility.

[0002]

2. Description of the Related Art Conventional printing methods that require dampening water make it difficult to control the delicate balance between dampening water and ink.
There have been major problems such as emulsification of the ink and mixing of the ink with the fountain solution, resulting in defective ink density and scumming, which causes wasted paper. In contrast, waterless lithographic plates have many advantages because they do not require fountain solution. Regarding a waterless planographic printing plate for performing planographic printing without using such dampening water, for example, Japanese Patent Publication No.
-23042, Japanese Patent Publication No. 46-16044, Japanese Patent Publication No. 5
No. 4-26923, JP-B-56-14976, JP-B-56-23150, JP-B-61-54222, JP-A-58-215411, JP-A-2-16561, JP-A-2-236550 and the like. Things have been proposed. Among them, a primer layer, a photopolymerizable photosensitive layer and a silicone rubber layer are applied in this order on a support, and the photopolymerizable photosensitive layer in the exposed area is polymerized and cured by exposure, and the adhesive force with the silicone rubber layer is also applied. The waterless planographic printing plate which forms the image area by making only the silicone rubber layer of the unexposed area strong during development has extremely excellent performance. On the other hand, in recent years, due to rapid advances in output systems such as prepress systems, imagesetters, and laser printers, printed images are converted into digital data, and printing plates are obtained by new plate making methods such as computer tow plates and computer tow cylinders. As methods have been proposed, new types of printing materials for these printing systems are desired and under development. However, many of these technologies are provided for conventional lithographic printing plates that are printed using fountain solution, but in reality, little is known for waterless lithographic plates. Examples of a waterless planographic printing plate that can be formed by laser writing are JP-B-42-21879, JP-A-50-158405, and JP-A-6-55523.
Publication, Japanese Patent Application Laid-Open No. 6-186750, US Pat.
3,705, WO-9401280, JP-A-7-314934, JP-A-5-94008 and the like. In these, a recording layer containing a laser light absorber such as carbon black and a self-oxidizing binder such as nitrocellulose, or an ink repellent silicone rubber layer is provided on a recording layer made of a kind of metal thin film. It is described that a part of the silicone rubber layer is removed by laser irradiation to make the ink adherent and print without water. However, these are because the removal of the silicone rubber layer depends on the ablation of the recording layer by laser irradiation,
The linearity of fine lines and the circularity of halftone dots are poor, and they are unsatisfactory as printed images, and their improvement has been strongly desired. Further, since the recording layer made of a metal thin film generally has a high reflectance to laser light and cannot effectively use the energy of laser light, a large amount of light energy is required for ablation of the recording layer, and therefore high speed In order to write an image by scanning, a large output laser light source is required, and there is a drawback that the image recording apparatus for it becomes large and expensive, and improvement thereof has been strongly desired.

[0003]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a laser writable waterless lithographic plate having good sensitivity and image reproducibility.

[0004]

Means for Solving the Problems As a result of intensive studies by the present inventors, a recording layer containing a metal and a metal sulfide and a silicone rubber layer are laminated in this order on a support. The object of the present invention has been achieved by a lithographic printing plate precursor that does not require fountain solution. In the present invention, the recording layer containing a mixture of a metal and one or more metal sulfides has a lower reflectance for laser light than the recording layer containing a single metal, and the energy of laser light can be effectively used. As a result, the sensitivity and image reproducibility by laser writing are improved.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Metals of the recording layer used in the present invention include Mg, Sc, Y, Ti, Zr, Hf, V and N.
b, Ta, Cr, Mo, W, Mn, Re, Fe, Co,
Ni, Ru, Rh, Pd, Ir, Pt, Cu, Ag, A
u, Zn, Cd, Al, Ga, In, Si, Ge, P
b, Sn, As, Sb, Bi, Se, Te, which may be used alone or in combination of two or more or as an alloy. Among these metals, Mg, Mn, Zn, Al, I having a low melting point or a low reflectance are used.
n, Sn, Bi, Te and the like are preferable, and Mg, Mn, Zn, Al, In and Sn are more preferable from the viewpoint of no pollution.

The metal sulfide of the recording layer used in the present invention
Then, CrS, Cr_TwoS, Cr_TwoS _Three, MoS_Two, Mn
S, FeS, FeS_Two, CoS, Co_TwoS_Three, NiS,
Ni_TwoS, PdS, Cu_TwoS, Ag_TwoS, ZnS, In_TwoS
_Three, In_TwoS_Two, GeS_X(X is in the range of 0 <X ≦ 2
Number), SnS, SnS_Two, PdS, As_TwoS_Three, Sb_TwoS
_Three, Bi_TwoS_Three, Ga_TwoS_ThreeAnd these sulfides
One or two or more are used. Especially preferred gold
Group sulfides are NiS, In_TwoS_Three, GeS_X(X is 0
<Number in the range of X ≦ 2), SnS, In_TwoS_ThreeIt is.

As the method for providing the recording layer of the present invention, various methods such as vapor deposition (resistance heating, electron beam heating), sputtering, ion plating and the like can be used, and a multilayer of a metal layer and a metal sulfide layer ( It may have an alternate multilayer structure of metal layers and metal sulfide layers.) Alternatively, it may be provided as a mixed layer of metal and metal sulfide. Examples of the layer structure of the recording layer of the present invention are shown in FIGS. Further, a multilayer structure of a mixed layer of metal and metal sulfide and a metal layer and / or a metal sulfide layer may be used. At this time, the volume percentage of the composition ratio of the metal sulfide in the recording layer is 1 to 80%, preferably 5 to 60%, more preferably 10%.
４０40%.

Further, the thickness of the recording layer used in the present invention varies depending on the material, but if the thickness is less than 50 Å, the light absorption rate is small and the sensitivity decreases, and if it exceeds 1000 Å, the sensitivity and the image reproducibility decrease. , 50 to 1000 angstroms are preferable, and 100 to 800 angstroms are more preferable.
Further, the optical density of the recording layer in this case is preferably 0.15 or more.

The waterless planographic printing plate of the present invention must have flexibility so that it can be set in an ordinary printing machine and, at the same time, withstand the load applied during printing. Therefore, as a typical support, a coated paper, a metal plate such as aluminum, a plastic film such as polyethylene terephthalate, rubber or a composite thereof can be mentioned, and more preferably aluminum or an aluminum-containing alloy. (For example, an alloy of a metal such as silicon, copper, manganese, magnesium, chromium, zinc, lead, bismuth, and nickel with aluminum) and a plastic film. The thickness of the support is appropriately 25 μm to 3 mm, preferably 75 μm to 500 μm, but the optimum thickness varies depending on the type of support used and printing conditions. Generally, 100 μm to 300 μm is most preferable.

In the present invention, the support may be subjected to a surface treatment such as corona treatment or a primer layer may be provided in order to improve the adhesion between the support and the recording layer, improve the printing characteristics or increase the sensitivity. Examples of the primer layer used in the present invention include those obtained by exposing and curing various photosensitive polymers as disclosed in JP-A-60-22903 before laminating the photosensitive resin layer, JP-A-6
A thermosetting epoxy resin disclosed in JP-A-2-50760, a gelatin hardened film disclosed in JP-A-63-133151, and a JP-A-3-200965 publication. Using a conventional urethane resin and a silane coupling agent, and JP-A-3-
The thing etc. which used the urethane resin disclosed by 273248 gazette can be mentioned. In addition, those obtained by hardening gelatin or casein are also effective. Further, in the above primer layer, polyurethane, polyamide, styrene / butadiene rubber, carboxy modified styrene / butadiene rubber, acrylonitrile / butadiene rubber, carboxy modified acrylonitrile / butadiene rubber, polyisoprene, acrylate rubber, polyethylene, chlorinated polyethylene, chlorine Polymers such as modified polypropylene, vinyl chloride / vinyl acetate copolymer, chlorinated rubber, halogenated polyhydroxystyrene, and nitrocellulose may be added. The addition ratio is arbitrary, and the primer layer may be formed only by the additive as long as the film layer can be formed. In addition, for these primer layers, a dye, a photopolymerization initiator, an adhesion aid (for example, a polymerizable monomer, a diazo resin, a silane coupling agent, a titanate coupling agent or an aluminum coupling agent) is used in accordance with the above purpose. Further, additives such as pigments, silica powder and titanium oxide powder may be contained. After the application, it can be cured by exposure. Generally, the coating amount of the primer layer is suitably in the range of 0.05 to 10 g / m ² by dry weight, preferably from 0.1 to 8 g / m ^2, more preferably 0.2-5 g / m ² Is.

Silicone rubber used in the present invention
The layer is preferably a crosslinked silicone rubber layer, particularly
The following composition A (condensation type silicone) or B (addition type silicone)
A film formed by curing (corn) is preferably used.
You. Composition A (a) 100 parts by weight of diorganopolysiloxane (b) Condensation type crosslinking agent 3 to 70 parts by weight (c) Catalyst 0.01 to 40 parts by weight The diorganopolysiloxane of the component (a) has the following composition.
General formula: -Si (R¹) (R^Two) Repeats as indicated by O-
A polymer having a repeating unit, R¹And R ^TwoIs carbon
Number 1 to 10 are an alkyl group, a vinyl group, and an aryl group,
It may also have other suitable substituents. general
For R¹And R^TwoMore than 60% is methyl group, or
It is a halogenated vinyl group, halogenated phenyl group, etc.
Are preferred.

It is preferable to use a diorganopolysiloxane having hydroxyl groups at both ends. The component (a) has a number average molecular weight of 3,000 to 1
0,000, and more preferably 10,000 to
70,000. Component (b) may be of any type as long as it is a condensation type, but is preferably one represented by the following general formula.

R ¹ _m · Si · X _n (m + n = 4, n is 2 or more) Here, R ¹ has the same meaning as R ¹ described above, and X is a substituent as shown below. Cl, Br, halogen H or OH, such as ^{I, -OCOR 3, -OR 3,} -O-N
^{= C (R 4) (R} 5), - N (R 4) (R 5) organic substituent such as. Here, R ³ represents an alkyl group having 1 to 10 carbon atoms and an aryl group having 6 to 20 carbon atoms, and R ⁴ and R ⁵ represent an alkyl group having 1 to 10 carbon atoms. Component (c) is tin, zinc,
Known catalysts such as metal carboxylate salts of lead, calcium, manganese and the like, for example, dibutyl laurate, lead octylate, lead naphthenate and the like, and chloroplatinic acid and the like can be mentioned.

Composition B (d) 100 parts by weight of diorganopolysiloxane having an addition-reactive functional group (e) 0.1 to 25 parts by weight of organohydrogenpolysiloxane (f) 0.00001 to 1 part by weight of addition catalyst The diorganopolysiloxane having an addition-reactive functional group of the component (d) is an organopolysiloxane having at least two alkenyl groups (more preferably vinyl groups) directly bonded to a silicon atom in one molecule. The group may be at the terminal or in the middle of the molecular weight, and the organic group other than the alkenyl group is a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms or an aryl group. Component (d) may optionally have a trace amount of hydroxyl groups. The component (d) has a number average molecular weight of 3,000 to 100,00.
0, more preferably 10,000 to 70,000
0. As the component (e), polydimethylsiloxane having hydrogen groups at both ends, α, ω-dimethylpolysiloxane,
Examples include (methylsiloxane) (dimethylsiloxane) copolymers with methyl groups at both ends, cyclic polymethylsiloxane, polymethylsiloxane with trimethylsilyl groups at both ends, and (dimethylsiloxane) (methylsiloxane) copolymers with trimethylsilyl groups at both ends. To be done. The component (f) is arbitrarily selected from known compounds, and is particularly preferably a platinum compound, such as platinum alone, platinum chloride, chloroplatinic acid, and olefin-coordinated platinum. For the purpose of controlling the curing rate of these compositions, vinyl group-containing organopolysiloxane such as tetracyclo (methylvinyl) siloxane, carbon-carbon triple bond-containing alcohol,
Acetone, methyl ethyl ketone, methanol, ethanol
It is also possible to add a crosslinking inhibitor such as propylene glycol or propylene glycol monomethyl ether.

In the silicone rubber layer, if necessary, fine powder of an inorganic material such as silica, calcium carbonate, titanium oxide, an adhesion aid such as a silane coupling agent, a titanate coupling agent or an aluminum coupling agent. Alternatively, a photopolymerization initiator may be added. The silicone rubber layer in the present invention has a problem that the ink repulsion property is reduced when the thickness is small and scratches are likely to occur, and when the thickness is large, the developability is deteriorated. preferably 0.5 to 5 g / m ² in the coating amount, more preferably from 1 to 3 g / m ^2. In the waterless lithographic plate described here, various silicone rubber layers may be further coated on the silicone rubber layer. Further, to protect the surface of the silicone rubber layer, a transparent film such as polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate, cellophane, etc. is laminated on the silicone rubber layer, or a polymer coating is applied. May be applied. These films may be used after being stretched. Further, the surface may be matted, but the one without matting is preferable in the present invention.

In the present invention, the laser light energy used for recording is absorbed in the recording layer of the waterless planographic printing plate of the present invention to ablate (melt / aggregate) the recording layer.
As a result, the interface between the recording layer in the laser-exposed area and the silicone rubber layer disappears, and the exposed silicone layer is easily removed. In the present invention, laser light is used to expose a waterless lithographic plate. The laser used is not particularly limited as long as it gives an exposure amount necessary for the adhesive force to be sufficiently removed so that the silicone rubber layer is peeled and removed, and a gas laser such as an Ar laser or a carbon dioxide gas laser is used. Solid state lasers, such as YAG lasers,
And a semiconductor laser etc. can be used. Normal output is 5
A laser of 0 mW class or higher is required. Semiconductor lasers and semiconductor-excited solid-state lasers (such as YAG lasers) are preferably used in terms of practicality such as maintainability and price. The recording wavelength of these lasers is in the infrared wavelength region, and an oscillation wavelength of 800 nm to 1100 nm is often used. In addition, JP-A-6-186750
It is also possible to perform exposure using the imaging device described in the publication. The film for protecting the surface of the silicone rubber layer may be used as it is at the time of laser exposure, or may be exposed after being peeled off.

As the developing solution used in the present invention, a known developing solution for a waterless planographic printing plate can be used.
From the viewpoint of safety, water or an aqueous solution of a water-soluble organic solvent containing water as a main component is preferable. In consideration of safety and flammability, the concentration of the water-soluble solvent is preferably less than 40% by weight. Known compounds include, for example, aliphatic hydrocarbons (hexane, heptane, "Isopar E, H, G" (manufactured by Esso Chemical Co., Ltd.) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.). ) Or a halogenated hydrocarbon (trichlene, etc.) to which the following polar solvent is added, or the polar solvent itself: alcohols (methanol, ethanol, propanol, isopropanol, benzyl alcohol, ethylene glycol monomethyl ether, 2-ethoxyethanol, Diethylene glycol monoethyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, polyethylene glycol monomethyl ether -Ketones (acetone, methyl ethyl ketone, etc.)-Esters (ethyl acetate, methyl lactate, butyl lactate, etc.)
Propylene glycol monomethyl ether acetate,
Diethylene glycol acetate, diethyl phthalate, etc.)-Others (triethyl phosphate, tricresyl phosphate, etc.) Also, water can be added to the organic solvent-based developer or the organic solvent can be added to water using a surfactant or the like. Solubilized,
Further, there may be mentioned those obtained by adding an alkali agent (for example, sodium carbonate, diethanolamine, sodium hydroxide, etc.), or simply water (tap water, pure water, distilled water, etc.). The development can be performed by a known method, for example, by rubbing the plate surface with a developing pad containing the above-described developer, or rubbing the developer with the developer brush in water after pouring the developer onto the plate surface. The developer can be developed at any temperature, but is preferably from 10C to 50C. As a result, the ink repellent layer in the image area is removed, and that area becomes the ink receiving area. When the plates thus processed are stacked and stored, it is preferable to insert and insert a slip sheet to protect the plates. The above-described development processing, or subsequent washing with water and drying processing can be performed by an automatic processor.
A preferable automatic processor is disclosed in Japanese Patent Laid-Open No. 2-2.
It is described in Japanese Patent Publication No. 20061. The waterless planographic printing plate of the present invention can also be developed by adhering the adhesive layer to the surface of the silicone rubber layer and then peeling off the adhesive layer. As the adhesive layer, any known adhesive layer that can adhere to the surface of the silicone rubber layer can be used. A flexible support provided with these adhesive layers is commercially available. For example, Sumitomo 3M's "Scotch tape # 851A"
It is commercially available under the trade name.

[0018]

EXAMPLES The present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples. Examples 1 to 10 and Comparative Examples 1 to 4 On a polyethylene terephthalate support having a thickness of 188 μm, the metal and the metal sulfide shown in Table 1 were separated from each other under the conditions of the vapor deposition vacuum degree of 5 × 10 ⁻⁵ Torr. A recording layer was formed by simultaneously performing resistance heating vapor deposition using an evaporation source. Restriction of the mixing ratio of the two was performed by arranging a quartz-crystal vibration type film thickness monitor for each evaporation source and controlling the evaporation rate thereby. The thickness of the recording layer at this time was 400 Å, and the composition ratio of the metal sulfide was 2% by volume.
Adjusted to 5%. Next, the following coating liquid is applied onto the recording layer, heated (110 ° C., 1 minute) and dried to form an addition type silicone rubber layer having a dry film thickness of 2 μm, and a waterless planographic printing plate is obtained. Obtained.

Composition of silicone rubber layer coating liquid: α, ω-divinylpolydimethylsiloxane (polymerization degree: about 700) 9.00 g ・ (CH ₃ ) ₃ -Si-O- (SiH (CH ₃ ) -O) ₈ -Si (CH _{3) 3} 0.60g · polydimethylsiloxane (polymerization degree: about 8000) 0.50 g · olefin - chloroplatinic acid 0.08 g · inhibitor _{[HC≡CC (CH 3) 2 -O} -Si (CH 3) ₃ ] 0.07g-55g from Isopar G (Esso Chemical Co., Ltd.)

The waterless planographic printing plate of the present invention thus obtained was treated with a wavelength of 10
Continuous line writing was performed using a semiconductor-excited YAG laser with a wavelength of 64 nm and a beam diameter of 40 μm (1 / e ² ) at different scanning speeds, and then the surface of the plate was wiped with a developing pad containing isopropanol, and the laser-irradiated silicone was used. The rubber layer was removed. At this time, the silicone layer in the unirradiated area of the laser was not removed and was held on the waterless planographic surface, and the scanning speed at which a silicone image with a sharp edge could be formed was used as a writing threshold, and the sensitivity and line image reproducibility were compared. I went. The results are shown in Table 1.

[0021]

[Table 1]

From the above, it has been clarified that a recording layer containing a metal and a metal sulfide can produce a good image by laser irradiation with low energy as compared with a recording layer having a single metal layer.

Example 11 On 100 μm thick polyethylene terephthalate support
A coating solution having the following composition is applied to the above and heated (100 ° C., 1
Min) and dry to obtain a plastic film with a dry film thickness of 0.2 μm.
Except for providing an immersion layer, the same method as in Example 1
I got a lithographic plan. Output 110mW, wave on this waterless planographic
Long 830 nm, beam diameter 10 μm (1 / e ^Two) Semiconductor
Writing at a main scanning speed of 6 m / sec using a laser
After that, Scotch tape # 851A (Sumitomo Three
(Made by M Co., Ltd.) on the surface of the silicone rubber layer,
Peel off and remove the silicone rubber layer on the laser irradiation area.
Was. Waterless lithographic stamp with a resolution of 7 μm and sharp edges
A plate was formed. Under these recording conditions, 200 dots
When formed, halftone dot area ratio is from 2% to 98%
Could be formed on top.

Composition of coating liquid for primer layer (parts by weight) 1 part chlorinated polyethylene-(C ₂ H ₄ -yCly) _n -y = 1.7, n = 200 10 parts methyl ethyl ketone 100 parts cyclohexane

Example 12 On a polyethylene terephthalate support having a thickness of 188 μm, Al was vapor-deposited by resistance heating under the conditions of a vapor deposition vacuum degree of 5 × 10 ⁻⁵ Torr to a thickness of 300 Å, and then SnS was deposited. , Evaporation degree 5 × 10 ^-5 To
Under the condition of rr, electron beam evaporation was performed so as to have a thickness of 100 Å, and a recording layer was formed. Other than that, when the sensitivity and the line image reproducibility were evaluated in the same manner as in Examples 1 to 10, the writing threshold value was 6.5 m / sec.

Example 13 On a polyethylene terephthalate support having a thickness of 188 μm, Al and SnS were separately heated under the conditions of vapor deposition vacuum degree of 5 × 10 ⁻⁵ Torr, Al was resistance heating, and SnS was SnS.
Was simultaneously vapor-deposited with an electron beam to form a layer containing a metal and a metal compound. Restriction of the mixing ratio of the two was performed by arranging a quartz-crystal vibration type film thickness monitor for each evaporation source and controlling the evaporation rate thereby. At this time, the thickness of the mixed layer of Al and SnS is 350 Å, and the composition ratio of SnS is 14% by volume.
%. Next, ZnS is vapor-deposited at a vacuum degree of 5 × 10 ^−5.
A recording layer was formed by performing electron beam evaporation under a Torr condition so as to have a thickness of 50 Å. Other than that, when the sensitivity and the line image reproducibility were evaluated in the same manner as in Examples 1 to 10, the writing threshold value was 7 m / sec.

Comparative Example 5 A recording layer was formed on a polyethylene terephthalate support having a thickness of 188 μm by resistance heating vapor deposition of Al so as to have a thickness of 400 Å under the conditions of vapor deposition vacuum degree of 5 × 10 ⁻⁵ Torr. did. Other than that, Example 12,
When the sensitivity and the line image reproducibility were evaluated in exactly the same manner as in No. 13, the writing threshold value was 2 m / sec.

[0028]

INDUSTRIAL APPLICABILITY The waterless planographic printing plate of the present invention is capable of heat mode recording with a laser beam and is excellent in sensitivity and image reproducibility.

[Brief description of drawings]

FIG. 1 is an example in which a metal layer and a metal sulfide layer are laminated in this order on a support.

FIG. 2 is an example in which a metal sulfide layer and a metal layer are laminated in this order on a support.

FIG. 3 is an example in which a metal sulfide layer and a metal layer are multilayer-coated in this order on a support.

FIG. 4 is an example in which a metal sulfide layer and a metal layer are provided in this order as an alternate multilayer structure on a support.

FIG. 5 shows an example in which a mixed layer of metal and metal sulfide is provided on a support.

FIG. 6 shows an example in which a mixed layer of metal and metal sulfide and a metal sulfide layer are laminated in this order on a support.

FIG. 7 shows an example in which a metal sulfide layer and a mixed layer of metal and metal sulfide are laminated in this order on a support.

[Explanation of symbols]

 1: Support 2: Metal layer 3: Metal sulfide 4: Silicone rubber layer 5: Mixed layer of metal and metal sulfide

Claims (1)

[Claims] 1. A lithographic printing original plate not requiring a fountain solution, which comprises a recording layer containing a metal and a metal sulfide and a silicone rubber layer laminated in this order on a support.