JP2938400B2 - A method for preparing a lithographic printing plate by image-wise heating of an image forming element using a thermal head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a method of making a lithographic printing plate including imagewise heating of an imaging element using a thermal head.

[0002]

BACKGROUND OF THE INVENTION Lithographic printing is a method of printing from a specially manufactured surface in which some areas can receive lithographic ink but do not receive ink when other areas are wetted with water. It is. The areas that receive ink form the printed image areas, and the ink-reject areas form the background areas.

In the field of photolithographic printing, photographic materials are exposed (negative-working) or non-working on hydrophilic backgrounds.
It is image-wise receptive to oily or greasy inks in the exposed (positive-working) areas.

In the preparation of conventional lithographic printing plates, also called surface lithographic plates or planographic printing plates, a photosensitive composition is provided on a support which has an affinity for water or which obtains such an affinity by chemical treatment. Is coated. Coatings for that purpose include photopolymer layers containing diazo compounds, dichromate-sensitized hydrophilic colloids and various synthetic photopolymers. In particular, diazo-sensitized systems are widely used.

[0005] When the photosensitive layer is image-wise exposed, the exposed image areas become insoluble and the unexposed areas remain soluble. The printing plate is then developed using a suitable liquid,
The diazonium salt or diazo resin in the non-exposed area is removed.

[0006] Commercially available diazo-based printing plates most commonly use anodized and roughened aluminum as a support with a hydrophilic surface. However, commercially available printing plates using a flexible support such as paper provided with a hydrophilic layer are also available. For example, Lithocra
ft 10008 FOTOPLATE ^™ is a diazo-based printing plate comprising a hydrophilic layer on a paper support and a diazo-based photosensitive layer provided thereon. According to the supplier's printing plate instructions, the printing plate exposes the lithographic printing plate material or imaging element image-wise, attaches the exposed imaging element to a printing press, and lithograf
t ^R 10008 Developer Desensitizer (Developer
It can be manufactured by wiping with a Desentizer. The printing plate instructions also include methods that do not use a developer desensitizer. However, such methods most often result in poor lithographic performance, and in fact almost always require a developer desensitizer.

[0007] A significant disadvantage of the photosensitive imaging elements as described above for making printing plates is that they must be shielded from light. The mounting of the image-wise exposed imaging element is generally performed in standard daylight,
This is a significant drawback when on-press development is intended, as the handling time for the mounting of the imaging element is limited. Furthermore, diazo-based aluminum type printing plates are not completely suitable for on-press development.

[0008] On the other hand, methods are known for making printing plates that involve the use of imaging elements that are heat-sensitive rather than light-sensitive. For example, Research Di of January 1992
sclosure no. No. 33303 discloses a thermosensitive imaging element comprising on a support a crosslinked hydrophilic layer comprising hydrophobic thermoplastic polymer particles and an infrared absorbing pigment such as carbon black. Image-wise exposure to an infrared laser causes the hydrophobic thermoplastic polymer particles to solidify image-wise, thereby rendering the surface of the imaging element and these areas ink-receiving without further development. A disadvantage of this method is that the resulting printing plate is easily damaged since some pressure can be applied to the non-printing areas, which can become ink receptive. Furthermore, under marginal conditions, the lithographic performance of such printing plates can be poor, and thus such printing plates have a low lithographic latitude.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a printing plate having excellent printing properties in a simple and environmentally friendly manner.

[0010] Further objects of the present invention will become clear from the description hereinafter.

In accordance with one aspect, the present invention provides: (1) an ink-ink-repellant layer comprising a (i) a cross-linked hydrophilic binder and (ii) a hydrophilic bond on a flexible support. Heating the image-forming element comprising the image-forming layer comprising the hydrophobic thermoplastic polymer particles dispersed in the agent using a thermal head; (2) heating the image-formed element thus obtained, The present invention relates to a method for preparing a lithographic printing plate including a step of developing with water or an aqueous liquid.

The present invention further provides (1) an ink-repellent layer comprising (i) a crosslinked hydrophilic binder on a flexible support and (ii) a hydrophobic thermoplastic dispersed in the hydrophilic binder. Image-wise heating the image-forming element comprising the image-forming layer comprising the polymer particles using a thermal head; (2) placing the image-wise heated image-forming element thus obtained on a printing cylinder of a printing press attachment,
A method for preparing a lithographic printing plate, comprising a step of developing by supplying an aqueous dampening solution and / or ink to the image forming layer while rotating the printing cylinder.

The present invention is directed to (1) an ink-repellent layer containing (i) a crosslinked hydrophilic binder on a flexible support, and (ii) a hydrophobic thermoplastic polymer dispersed in the hydrophilic binder. Mounting the imaging element comprising the imaging layer comprising the particles on a printing cylinder of a printing press; (2) heating the imaging element imagewise using a thermal head; (3) imagewise heating thus obtained. Also disclosed is a method of making a lithographic printing plate comprising developing the imaged element by supplying an aqueous dampening solution and / or ink to the image forming layer while rotating the printing cylinder.

According to a further aspect of the present invention, there is provided (1) an ink-repellent layer comprising a (i) a crosslinked hydrophilic binder on a flexible support and (ii) a hydrophobic dispersed in the hydrophilic binder. Heating the image-forming element comprising the image-forming layer containing the thermoplastic thermoplastic polymer particles using a thermal head; (2) printing the image-wise heated image-forming element thus obtained without developing it (3) rotating the printing cylinder while supplying an aqueous dampening solution and / or supplying ink to the image forming layer of the image forming element; (4) the image forming element A method is disclosed for making multiple copies of a manuscript, including the step of transferring ink from a to a receiving element.

The present invention is directed to (1) an ink-repellent layer comprising (i) a crosslinked hydrophilic binder on a flexible support and (ii) a hydrophobic thermoplastic polymer dispersed in the hydrophilic binder. Mounting the imaging element comprising the imaging layer containing the particles on a printing cylinder of a printing press; (2) heating the imaging element imagewise using a thermal head; (3) the image of the imaging element. Rotating the printing cylinder while supplying an aqueous dampening solution and / or ink to the forming layer; (4) transferring multiple copies of the original document including transferring ink from the imaging element to an image receiving element. Manufacturing methods are also provided.

[0016]

DETAILED DESCRIPTION OF THE INVENTION An imaging element for use in accordance with the present invention comprises an imaging layer comprising hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder on a lithographic base hydrophilic surface. Preferably, the hydrophilic binder of the imaging layer used in connection with the present invention is not crosslinked or is only slightly crosslinked.

According to the present invention, the lithographic base comprises a flexible support, for example paper or plastic film, provided with an ink-repellent layer comprising a cross-linked hydrophilic binder. Particularly suitable ink-repellent layers are formaldehyde, glyoxal, polyisocyanate or hydrolyzed tetra-
It can be obtained from a hydrophilic binder cross-linked using a cross-linking agent such as an alkyl orthosilicate. Hydrolyzed tetra-alkyl orthosilicate is particularly preferred.

As the hydrophilic binder, hydrophilic (co) polymers such as vinyl alcohol, acrylamide, methylol acrylamide, methylol methacrylamide, acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate homopolymer and copolymer, or anhydrous Maleic acid / vinyl methyl ether copolymer can be used. The hydrophilicity of the (co) polymer or (co) polymer mixture used is
It is preferred that the hydrophilicity of the polyvinyl acetate hydrolyzed to at least 60% by weight, preferably to the extent of 80% by weight, be the same or higher.

The amount of crosslinking agent, in particular tetraalkyl orthosilicate, is preferably at least 0.2 parts by weight, preferably 0.5 to 5 parts by weight, per part by weight of hydrophilic binder.
More preferably, the amount is 1.0 part by weight to 3 parts by weight.

[0020] The ink-repellent layer in the lithographic base used according to this embodiment preferably also contains substances which increase the mechanical strength and porosity of the layer. Colloidal silica can be used for this purpose. The colloidal silica used can be in the form of any commercially available water-dispersion of colloidal silica, for example having an average particle size of up to 40 nm, for example 20 nm. In addition, inert particles of larger dimensions than colloidal silica, for example J.I. Colloid and Interface S
ci. , Vol. 26, 1968, pages 62-6
9. Silica produced according to Stoeber according to 9
Alternatively, alumina particles or particles of titanium dioxide or other heavy metal oxides having an average diameter of at least 100 nm can be added. The insertion of these particles gives the surface of the ink-repellent layer a uniform rough texture consisting of microscopic hills and valleys, which serves as a storage for water in background areas.

Ink in lithographic base according to this embodiment
The thickness of the repellent layer can vary in the range of 0.2 to 25 μm, preferably 1 to 10 μm.

Inks suitable for use in accordance with the present invention
Specific examples of repellent layers are EP-A 601240, GB-
P-1419512, FR-P-2300354, US
-P-397660, US-P-4284705 and EP-A 514490.

As a lithographic base flexible support in connection with this embodiment, a plastic film such as a substrate (su)
It is particularly preferable to use a polyethylene terephthalate film, a polyethylene naphthalate film, a cellulose acetate film, a polystyrene film, a polycarbonate film and the like. The plastic film support can be opaque or transparent.

It is particularly preferable to use a polyester film support provided with an adhesion promoting layer. Particularly suitable adhesion-promoting layers for use according to the invention are EP-A 61
9527, EP-A 620502 and EP-A 61
9525, including a hydrophilic binder and colloidal silica. The amount of silica in the adhesion promoting layer is 1 m ² per 200mg and 1 m ² per 750mg is preferred. Further, the ratio of silica to hydrophilic binder is preferably greater than 1, and the surface area of the colloidal silica is preferably at least 300 m ² per gram, preferably 500 m ² per gram.
Is more preferable.

According to the present invention, an image forming layer is provided on a hydrophilic surface. Optionally, one or more intermediate layers can be provided between the lithographic base and the image forming layer. The imaging layer associated with the present invention comprises hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder.

Suitable hydrophilic binders for use in the image forming layer in connection with the present invention are, for example, synthetic homo or copolymers such as polyvinyl alcohol, poly (meth) acrylic acid, poly (meth) acrylamide, polyhydroxyethyl ( Meth) acrylates, polyvinyl methyl ethers or natural binders such as gelatin, polysaccharides such as dextran, pullulan, cellulose, gum arabic, arginic acid.

The hydrophobic thermoplastic polymer particles used in connection with the present invention preferably have a coagulation temperatur of at least 35 ° C., more preferably at least 50 ° C.
e). Coagulation can result from softening or melting of the thermoplastic polymer particles under the influence of heat. There is no specific upper limit for the coagulation temperature of the thermoplastic hydrophobic polymer particles, but the temperature must be well below the decomposition temperature of the polymer particles. Preferably, the coagulation temperature is at least 10 ° C. below the temperature at which the decomposition of the polymer particles takes place. When the polymer particles are subjected to temperatures above the coagulation temperature, they coagulate to form hydrophobic aggregates in the hydrophilic layer, at which point the hydrophilic layer becomes insoluble in fresh water or aqueous liquids. .

Particular examples of hydrophobic thermoplastic polymer particles for use in connection with the present invention include, for example, polyethylene,
Polyvinyl chloride, polymethyl (meth) acrylate, polyethyl (meth) acrylate, polyvinylidene chloride,
Polystyrene, polyacrylonitrile, polyvinyl carbazole, and the like, or a copolymer thereof. Most preferably, polymethyl (meth) acrylate or polystyrene is used.

The weight average molecular weight of the polymer is from 5,000 to
It can be in the range of 1,000,000 g / mol.

The hydrophobic particles can have a particle size of from 0.01 μm to 50 μm, more preferably from 0.05 μm to 10 μm, most preferably from 0.05 μm to 2 μm.

The polymer particles can be present as a dispersion in the aqueous coating solution of the image-forming layer, US Pat.
It can be prepared by the method disclosed in -3.476.937. Other methods particularly suitable for the preparation of aqueous dispersions of thermoplastic polymer particles are:-dissolving a hydrophobic thermoplastic polymer in an organic solvent immiscible with water;-dissolving the solution thus obtained in water or an aqueous medium. Dispersing therein;-removing the organic solvent by evaporation.

Preferably, the amount of hydrophobic thermoplastic polymer particles contained in the image forming layer is greater than 30% by weight, more preferably at least 50% by weight, and most preferably at least 65% by weight.

According to a particular embodiment related to the present invention, the imaging layer may further comprise a diazonium salt, a diazo resin or an aryldiazosulfonate resin. Such offers the advantage that printability can be improved by applying global UV exposure to the developed imaging element following image-wise heating and development. But such an implementation is not on-press development,
Only practical for off-line exposure and development.

Examples of low molecular weight diazonium salts for use in the present invention are: benzidine tetrazonium chloride, 3,
3′-dimethylbenzidine tetrazonium chloride,
3,3′-dimethoxybenzidine tetrazonium chloride, 4,4′-diaminodiphenylamine tetrazonium chloride, 3,3′-diethylbenzidine tetrazonium sulfate, 4-aminodiphenylaminediazonium sulfate, 4-aminodiphenylaminediazonium chloride, Includes 4-piperidinoanilinediazonium sulfate, 4-diethylaminoanilinediazonium sulfate, and oligomer condensation products of diazodiphenylamine and formaldehyde.

Examples of diazo resins useful in the present invention include the condensation products of aromatic diazonium salts as photosensitive materials. Such condensation products are known and are described, for example, in DE 1214086. They are generally polynuclear aromatic diazonium compounds in strong acid media, preferably substituted or unsubstituted diphenylamine-4-.
It is prepared by condensation of a diazonium salt with an active carbonyl compound, preferably formaldehyde.

Examples of aryldiazosulfonate resins are E
It is described in P-A 339393 and EP-A507008, and the description thereof is incorporated herein by reference.

According to the method of the present invention for obtaining a printing plate, the imaging element is image-wise heated using a thermal head, for example in a thermal printer, and subsequently mounted on a printing cylinder of a printing press. According to a preferred embodiment, the printing press is then started and the dampening roller supplying the dampening fluid is lowered onto the imaging element while rotating the printing cylinder on which the imaging element is mounted, followed by Lower the ink roller. Generally, after about 10 rotations of the printing cylinder, the first clear and useful prints are obtained.

According to a variant, the ink roller and the dampening roller can be lowered simultaneously, or the ink roller can be lowered first.

Suitable fountain solutions that can be used in connection with the present invention are generally aqueous liquids having an acidic pH and containing alcohols such as isopropanol. There is no particular restriction on the fountain solution useful in the present invention, and a commercially available fountain solution also known as a fountain solution can be used.

The image-forming layer of the image-wise heated imaging element may be covered with a water-soaked cotton pad or sponge prior to mounting the imaging element on the printing press, or at least before starting up the printing press. It may be advantageous to wipe with. This will remove some non-image areas, but will effectively not develop the imaging element. However, it has the advantage that possible substantial contamination of the dampening system and ink of the printing press used is avoided.

According to a variant, the imaging element is first mounted on the printing cylinder of a printing press and then heated image-wise directly on the printing press. Following heating, the imaging element can be developed as described above. This embodiment requires that the thermal head be incorporated into the printing press, and offers the advantage of reducing the overall processing time between large pasting of the original (eg, computer generated) and printing of the actual copy.

According to yet another method in connection with the present invention, the imaging element can be image-wise heated and subsequently developed with fresh water or an aqueous liquid.

The present invention will now be illustrated using the following examples, which are not intended to limit the invention. All parts are by weight unless otherwise specified.

[0044]

【Example】

Example 1 Preparation of a lithographic base 21.5% TiO ₂ in deionized water (average particle size 0.3
０．５0.5 μm) and 2.5% of polyvinyl alcohol to 440 g of a dispersion, followed by stirring with 5 g of water in water.
250 g of a 25% by weight polyvinyl alcohol solution, 105 g of a 22% hydrolyzed tetramethyl orthosilicate emulsion in water and 12 g of a 10% solution of a wetting agent were added.

To this mixture was added 193 g of deionized water and the pH was adjusted to pH = 4.

The resulting dispersion is coated on a polyethylene terephthalate film support (coated with a hydrophilic adhesive layer) to a wet coating thickness of 50 g / m ² , dried at 30 ° C. and subsequently brought to a temperature of 57 ° C. 1
The film was hardened by applying for a week.

Further, Dormacid (P
An aqueous solution of a dextran modified with diethylaminoethyl group (available from Feifer & Langen) and a cationic wetting agent (pH = 5) at 1 / m ²
A dry coating thickness of 00 mg Dormacid was provided.

The resulting element was then heated at 57 ° C. for one week.

Preparation of the Imaging Element The following coating composition was prepared, coated on the lithographic base described above in an amount of 35 g / m ² (wet coating amount), and dried at 30 ° C. to form an image. The element was made.

Preparation of Coating Composition Polymethylmethacrylate stabilized with cetyltrimethylammonium bromide (40 nm) in deionized water
Of a 98% hydrolyzed polyvinyl acetate having a number average molecular weight of 200 000 g / mol (MOWIOL ^™ 56-98 available from Hoechst) in 63 g of a 20% dispersion of 5% solution 1
20 g, and 15 g of a 10% dispersion of Heliogen ^™ Blue (BASF) and 5% polyvinyl alcohol (MOWIOL ^™ 56-98) in water were added.
The condensation product of diphenylamine diazonium salt and formaldehyde in water (N available from PACS)
46 g of a 15% solution of EGALUX ^™ N18) and 20 g of a 15% solution of a condensation product of methoxydiphenylaminediazonium salt and formaldehyde (DIAZO No. 8 available from Fairmount) were slowly added. Finally, a cationic powder containing surfactant in water (Flourad ^™ FC available from 3M)
30 g of a 1.6% solution of 135) and 726 ml of water were added.

[0051] The imaging element prepared above copying of making and original printing plate DRYSTAR ^TM MATRIX
^TM DI2000 Thermal Printer (Agfa-Ge
(commercially available from Vaert NV) and then the non-heated parts were manually washed off as follows:-Place the heated imaging element on a flat solid surface;
Applying water thereto; wiping the surface of the imaging element with a soft sponge while applying firm pressure to the surface of the imaging element until all non-image parts have been removed, while rinsing with fresh water; The surface of the element was further rinsed with water and the excess water was removed using a soft paper to obtain a dry printing plate.

Next, this printing plate was prepared using VARN ^™ KOMP.
ABDick 360 ^™ with AC II dampening system
It was mounted on an offset printing press. Va as ink
nSon RB2329 ^TM and fountain solution as G671 ^TM
(Agfa-Gevaert NV) was used. Excellent prints were obtained without ink absorption in the non-image areas during printing.

Example 2 An imaging element was prepared as described in Example 1 and image-wise heated as in Example 1. The image-wise heated imaging element was then mounted on the press described in Example 1. The same ink and fountain solution as in Example 1 were used.

The surface of the imaging element was subsequently wiped with a soft sponge moistened with water, thereby removing some of the non-heated portions of the imaging element.

Subsequently, the printing press was started and the dampening solution was applied to the surface of the imaging element by lowering the dampening roller of the printing press. After 5 rotations, the ink roller was lowered as well, and after another 5 rotations, there was no ink absorption in the non-image area and excellent print quality was obtained.

Example 3 Preparation of Coating Composition Polymethylmethacrylate stabilized with cetyltrimethylammonium bromide (40 nm) in deionized water
135 g of a 20% dispersion of the formula (9) having a number average molecular weight of 200 000 g / mol.
60 g of a 5% solution of 8% hydrolyzed polyvinyl acetate (MOWIOL ^™ 56-98 available from Hoechst)
And 805 ml of water.

An imaging element was then prepared as described in the examples, using the above coating composition in place of the coating composition in Example 1.
A printing plate was subsequently prepared using the imaging element thus obtained and then printed as described in Example 1 using this printing plate.

There was no ink absorption in the non-image areas and 5000 copies of excellent prints were printed.

Example 4 An imaging element was prepared as described in Example 3 and heated image-wise as in Example 1. Subsequently, the image-forming element, which had been image-wise heated, was mounted on an offset printing machine as described in Example 1. Example 1
The same inks and fountains as in were used.

The surface of the imaging element was subsequently wiped with a soft sponge moistened with water, thereby removing some of the non-heated portions of the imaging element.

Subsequently, the printing press was started and the dampening solution was applied to the surface of the imaging element by lowering the dampening roller of the printing press. After 5 rotations, the ink roller was lowered as well, and after another 5 rotations, there was no ink absorption in the non-image area and excellent print quality was obtained. 5000 copies of excellent quality were printed.

The main features and aspects of the present invention are as follows.

1. (1) On a flexible support, (i) an ink-repellent layer containing a crosslinked hydrophilic binder and (ii) an image forming layer containing hydrophobic thermoplastic polymer particles dispersed in the hydrophilic binder. (2) A method for preparing a lithographic printing plate comprising the step of developing the image-forming element thus obtained, which is thus obtained, with water or an aqueous liquid. .

2. (1) On a flexible support, (i) an ink-repellent layer containing a crosslinked hydrophilic binder and (ii) an image forming layer containing hydrophobic thermoplastic polymer particles dispersed in the hydrophilic binder. (2) mounting the image-wise heated imaging element thus obtained on a printing cylinder of a printing press;
A method for preparing a lithographic printing plate, comprising a step of developing by supplying an aqueous dampening solution and / or ink to the image forming layer while rotating the printing cylinder.

3. (1) On a flexible support, (i) an ink-repellent layer containing a crosslinked hydrophilic binder and (ii) an image forming layer containing hydrophobic thermoplastic polymer particles dispersed in the hydrophilic binder. Mounting the image-forming element on a printing cylinder of a printing press; (2) heating the image-forming element image-wise using a thermal head; (3) heating the image-forming element thus obtained, A method for preparing a lithographic printing plate, comprising a step of developing by supplying an aqueous dampening solution and / or ink to the image forming layer while rotating the printing cylinder.

4. (1) On a flexible support, (i) an ink-repellent layer containing a crosslinked hydrophilic binder and (ii) an image forming layer containing hydrophobic thermoplastic polymer particles dispersed in the hydrophilic binder. (2) mounting the image-wise heated image-forming element thus obtained on a printing cylinder of a printing press without development; (3) said image-forming element comprising: Rotating the printing cylinder while supplying an aqueous fountain solution and / or ink to the imaging layer of the imaging element; and (4) transferring ink from the imaging element to an image receiving element. How to make multiple copies of a manuscript.

5. (1) On a flexible support, (i) an ink-repellent layer containing a crosslinked hydrophilic binder and (ii) an image forming layer containing hydrophobic thermoplastic polymer particles dispersed in the hydrophilic binder. Mounting the imaging element on a printing cylinder of a printing press; (2) heating the imaging element imagewise using a thermal head; and (3) aqueous dampening solution on the imaging layer of the imaging element. (4) rotating the printing cylinder while supplying ink and / or supplying ink; (4) A method of making multiple copies of an original, comprising transferring ink from the imaging element to an image receiving element.

6. 6. The method according to any one of the above items 1 to 5, wherein the flexible support is a plastic film.

7. A method according to any of the preceding claims, wherein the hydrophobic thermoplastic polymer particles have a coagulation temperature of at least 35C.

8. The method of claim 7 wherein said hydrophobic thermoplastic polymer particles are selected from the group consisting of polyethylene, polystyrene, polymethyl (meth) acrylate, polyvinyl chloride, polyethyl (meth) acrylate, polyvinylidene chloride, polyacrylonitrile, and polyvinyl carbazole. .

9. The above-mentioned 1-8, wherein the hydrophilic binder in the image forming layer is selected from the group consisting of polyvinyl alcohol, poly (meth) acrylic acid, poly (meth) acrylamide, polyhydroxyethyl (meth) acrylate, polyvinyl methyl ether and polysaccharide. A method according to any of the preceding clauses.

10. 10. The method according to any of the above items 1 to 9, wherein the hydrophilic binder in the ink-repellent layer is polyvinyl alcohol cross-linked with hydrolyzed tetra-alkyl orthosilicate.

11. The method of claim 1 wherein said imaging layer further comprises a diazonium salt, diazo resin or aryldiazosulfonate resin, wherein said imaging element is totally exposed to UV-light following development.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-8575 (JP, A) JP-A-51-63704 (JP, A) JP-A-5-24374 (JP, A) JP-A 62-85 164049 (JP, A) JP-A-7-1850 (JP, A) JP-A 8-108661 (JP, A) JP-A-2-115462 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B41N 1/14

Claims (5)

(57) [Claims] 1. An ink-repellent layer containing (i) a cross-linked hydrophilic binder and (ii) hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder, on a (1) flexible support. A lithographic method comprising: image-wise heating an image-forming element comprising an image-forming layer comprising a thermal head; and (2) developing the image-wise heated image-forming element thus obtained with water or an aqueous liquid. How to make a printing plate. 2. An ink-repellent layer containing (i) a cross-linked hydrophilic binder and (ii) a hydrophobic thermoplastic polymer particle dispersed in a hydrophilic binder, on a flexible support. Heating the image-forming element comprising the image-forming layer comprising the image-forming layer using a thermal head; (2) mounting the image-wise heated image-forming element thus obtained on a printing cylinder of a printing press;
A method for preparing a lithographic printing plate, comprising a step of developing by supplying an aqueous dampening solution and / or ink to the image forming layer while rotating the printing cylinder. 3. An ink-repellent layer containing (i) a cross-linked hydrophilic binder and (ii) hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder, on a flexible support. Mounting the imaging element comprising the imaging layer comprising the printing element on a printing cylinder of a printing press; (2) heating the imaging element image-wise using a thermal head; (3) image-wise heating the image thus obtained. A method of making a lithographic printing plate comprising developing an imaging element by supplying an aqueous dampening solution and / or ink to the imaging layer while rotating the printing cylinder. 4. An ink-repellent layer comprising (i) a crosslinked hydrophilic binder and (ii) hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder, on a flexible support. Heating the image-forming element comprising the image-forming layer comprising the image-forming layer with a thermal head; (2) mounting the image-wise heated image-forming element thus obtained on a printing cylinder of a printing press without development (3) rotating the printing cylinder while supplying an aqueous dampening solution and / or supplying ink to the image forming layer of the image forming element; (4) applying ink from the image forming element to the image receiving element; A method of making multiple copies of a manuscript, including the step of transferring. 5. An ink-repellent layer containing (i) a cross-linked hydrophilic binder and (ii) hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder, on a flexible support. Mounting the imaging element including the imaging layer including the image forming layer on a printing cylinder of a printing press; (2) heating the imaging element image-wise using a thermal head; (3) the imaging layer of the imaging element. Rotating the printing cylinder while supplying an aqueous dampening solution and / or supplying ink to the printhead; (4) a method for making multiple copies of an original document, comprising the step of transferring ink from the imaging element to an image receiving element. .