EP0881094B1 - Elément d'enregistrement thermosensible et procédé pour la fabrication de plaques lithographiques utilisant cet élément - Google Patents

Elément d'enregistrement thermosensible et procédé pour la fabrication de plaques lithographiques utilisant cet élément Download PDF

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Publication number
EP0881094B1
EP0881094B1 EP19970201559 EP97201559A EP0881094B1 EP 0881094 B1 EP0881094 B1 EP 0881094B1 EP 19970201559 EP19970201559 EP 19970201559 EP 97201559 A EP97201559 A EP 97201559A EP 0881094 B1 EP0881094 B1 EP 0881094B1
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EP
European Patent Office
Prior art keywords
layer
imaging element
heat
thermoplastic polymer
hydrophilic
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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EP19970201559
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German (de)
English (en)
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EP0881094A1 (fr
Inventor
Marc Van Damme
Joan Vermeersch
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Agfa Gevaert NV
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Agfa Gevaert NV
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Priority to DE1997603344 priority Critical patent/DE69703344T2/de
Priority to EP19970201559 priority patent/EP0881094B1/fr
Priority to US09/073,435 priority patent/US6106996A/en
Priority to JP10155391A priority patent/JPH10329440A/ja
Publication of EP0881094A1 publication Critical patent/EP0881094A1/fr
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Publication of EP0881094B1 publication Critical patent/EP0881094B1/fr
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
    • B41M5/36—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used using a polymeric layer, which may be particulate and which is deformed or structurally changed with modification of its' properties, e.g. of its' optical hydrophobic-hydrophilic, solubility or permeability properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C1/00—Forme preparation
    • B41C1/10—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme
    • B41C1/1008—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme by removal or destruction of lithographic material on the lithographic support, e.g. by laser or spark ablation; by the use of materials rendered soluble or insoluble by heat exposure, e.g. by heat produced from a light to heat transforming system; by on-the-press exposure or on-the-press development, e.g. by the fountain of photolithographic materials
    • B41C1/1025—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme by removal or destruction of lithographic material on the lithographic support, e.g. by laser or spark ablation; by the use of materials rendered soluble or insoluble by heat exposure, e.g. by heat produced from a light to heat transforming system; by on-the-press exposure or on-the-press development, e.g. by the fountain of photolithographic materials using materials comprising a polymeric matrix containing a polymeric particulate material, e.g. hydrophobic heat coalescing particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C1/00—Forme preparation
    • B41C1/10—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme
    • B41C1/1008—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme by removal or destruction of lithographic material on the lithographic support, e.g. by laser or spark ablation; by the use of materials rendered soluble or insoluble by heat exposure, e.g. by heat produced from a light to heat transforming system; by on-the-press exposure or on-the-press development, e.g. by the fountain of photolithographic materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C2210/00—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation
    • B41C2210/04—Negative working, i.e. the non-exposed (non-imaged) areas are removed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C2210/00—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation
    • B41C2210/06—Developable by an alkaline solution
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C2210/00—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation
    • B41C2210/08—Developable by water or the fountain solution
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C2210/00—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation
    • B41C2210/24—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation characterised by a macromolecular compound or binder obtained by reactions involving carbon-to-carbon unsaturated bonds, e.g. acrylics, vinyl polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C2210/00—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation
    • B41C2210/26—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation characterised by a macromolecular compound or binder obtained by reactions not involving carbon-to-carbon unsaturated bonds
    • B41C2210/262—Phenolic condensation polymers, e.g. novolacs, resols

Definitions

  • the present invention relates to a heat sensitive material for making a lithographic printing plate.
  • the present invention further relates to a method for preparing a printing plate from said heat sensitive material.
  • Lithography is the process of printing from specially prepared surfaces, some areas of which are capable of accepting lithographic ink, whereas other areas, when moistened with water, will not accept the ink.
  • the areas which accept ink form the printing image areas and the ink-rejecting areas form the background areas.
  • a photographic material is made imagewise receptive to oily or greasy ink in the photo-exposed (negative working) or in the non-exposed areas (positive working) on a hydrophilic background.
  • lithographic plates also called surface litho plates or planographic printing plates
  • a support that has affinity to water or obtains such affinity by chemical treatment is coated with a thin layer of a photosensitive composition.
  • Coatings for that purpose include light-sensitive polymer layers containing diazo compounds, dichromate-sensitized hydrophilic colloids and a large variety of synthetic photopolymers. Particularly diazo-sensitized systems are widely used.
  • the exposed image areas become insoluble and the unexposed areas remain soluble.
  • the plate is then developed with a suitable liquid to remove the diazonium salt or diazo resin in the unexposed areas.
  • thermoplastic polymer particles By image-wise exposure to an infrared laser, the thermoplastic polymer particles are image-wise coagulated thereby rendering the surface of the imaging element at these areas ink acceptant without any further development.
  • a disadvantage of this method is that the printing plate obtained is easily damaged since the non-printing areas may become ink accepting when some pressure is applied thereto. Moreover, under critical conditions, the lithographic performance of such a printing plate may be poor and accordingly such printing plate has little lithographic printing latitude.
  • EP-A-514145 discloses a heat sensitive imaging element including a coating comprising core-shell particles having a water insoluble heat softenable core component and a shell component which is soluble or swellable in aqueous alkaline medium.
  • Red or infrared laser light directed image-wise at said imaging element causes selected particles to coalesce, at least partially, to form an image and the non-coalesced particles are then selectively removed by means of an aqueous alkaline developer. Afterwards a baking step is performed.
  • the printing endurance of a so obtained printing plate is low.
  • EP-A-599510 discloses a heat sensitive imaging element which comprises a substrate coated with (i) a layer which comprises (1) a disperse phase comprising a water-insoluble heat softenable component A and (2) a binder or continuous phase consisting of a component B which is soluble or swellable in aqueous, preferably aqueous alkaline medium, at least one of components A and B including a reactive group or precursor therefor, such that insolubilisation of the layer occurs at elevated temperature and/or on exposure to actinic radiation, and (ii) a substance capable of strongly absorbing radiation and transferring the energy thus obtained as heat to the disperse phase so that at least partial coalescence of the coating occurs.
  • said plate After image-wise irradiation of the imaging element and developing the image-wise irradiated plate, said plate is heated and/or subjected to actinic irradiation to effect insolubilisation.
  • the printing endurance of a so obtained printing plate is low.
  • EP-A-625728 discloses an imaging element comprising a layer which is sensitive to UV- and IR-irradiation and which can be positive or negative working. This layer comprises a resole resin, a novolac resin, a latent Bronsted acid and an IR-absorbing substance. The printing results of a lithographic plate obtained by irradiating and developing said imaging element are poor.
  • US-P-5,340,699 is almost identical with EP-A-625728 but discloses the method for obtaining a negative working IR-laser recording imaging element.
  • the IR-sensitive layer comprises a resole resin,a novolac resin, a latent Bronsted acid and an IR-absorbing substance.
  • the printing results of a lithographic plate obtained by irradiating and developing said imaging element are poor.
  • US-P-4,708,925 discloses a positive working imaging element including a photosensitive composition comprising an alkali-soluble novolac resin and an onium-salt. This composition can optionally contain an IR-sensitizer. After image-wise exposing said imaging element to UV - visible - or eventually IR-radiation followed by a development step with an aqueous alkali liquid there is obtained a positive working printing plate. The printing results of a lithographic plate obtained by irradiating and developing said imaging element are poor.
  • EP-A-678380 discloses a lithographic printing member directly imageable by laser discharge, the member comprising (a) an ink-accepting first layer, characterized by ablative absorption of imaging radiation; (b) a second layer underlying the first layer, the second layer being at least partially soluble in a cleaning solvent; and (c) a hydrophilic metal substrate.
  • Said second layer consist of a hydrophilic binder, not of a dispersed hydrophobic thermoplastic polymer latex.
  • Ch 482551 discloses a thermosensitive recording material which comprises a support, a thermosensitive imaging layer which contains hydrophobic thermoplastic particles dispersed in a hydrophilic binder and that is coated on an intermediate layer comprising hydrophobic thermoplastic particles having a melting point or a softening point lower or practically equal to this of the hydrophobic thermoplastic particles present in the hydrophilic binder of the recording layer. Nowhere is disclosed that said intermediate layer is soluble or dispersible in an aqueous solution.
  • thermophilic base Especially heat sensitive imaging elements whereof the heat sensitive layer is directly applied on the hydrophilic base are hard to process to hydrophilic plates where the heat sensitive layer is totally removed in the non-image areas so that there is ink uptake in the non-image areas.
  • a method for obtaining lithographic printing plates comprising the steps of image-wise exposing to actinic light a heat-sensitive imaging element as described above and developing said exposed imaging element by means of an aqueous solution.
  • lithographic printing plates of high quality giving prints without ink uptake in the non-image areas can be obtained according to the method of the present invention using an imaging element as described above. More precisely it has been found that said printing plates are of high quality and are provided in a convenient way, thereby offering economical and ecological advantages.
  • An imaging element for use in accordance with the present invention comprises on a hydrophilic surface of a lithographic base in the order given a second layer including a dispersed hydrophobic thermoplastic polymer latex, said second layer being soluble or dispersible in an aqueous solution and a hydrophobic first layer that is sensitive to heat having at least a hydrophobic polymer resin binder and a compound that is capable of converting light into heat, said layer having a decreased or increased capacity for being penetrated and/or solubilised by an aqueous developer upon exposure to actinic light.
  • the second layer is contiguous to the first layer.
  • the first layer is an outermost layer.
  • the hydrophobic thermoplastic polymer latex present in the second layer can be dispersed in a hydrophilic binder.
  • the second layer comprising a hydrophilic binder used in connection with the present invention is preferably not crosslinked or only slightly crosslinked.
  • Suitable hydrophilic binders for use in said second layer in connection with this invention are water soluble (co)polymers for example synthetic homo- or copolymers such as polyvinylalcohol, a poly(meth)acrylic acid, a poly(meth)acrylamide, a polyhydroxyethyl(meth)acrylate, a polyvinylmethylether or natural binders such as gelatin, a polysaccharide such as e.g. dextran, pullulan, cellulose, arabic gum, alginic acid.
  • the hydrophilic binder can also be a water insoluble, alkali soluble or swellable resin having phenolic hydroxy groups and/or carboxyl groups.
  • the water insoluble, alkali soluble or swellable resin used in connection with the present invention comprises phenolic hydroxy groups.
  • Suitable water insoluble, alkali soluble or swellable resins for use in an image-forming layer in connection with this invention are for example synthetic novolac resins such as ALNOVOL, a registered trade mark of Reichold Hoechst and DUREZ, a registered trade mark of OxyChem and synthetic polyvinylfenols such as MARUKA LYNCUR M, a registered trade mark of Dyno Cyanamid.
  • the hydrophobic thermoplastic polymer latex can also be dispersed in an aqueous medium without a binder.
  • the hydrophobic thermoplastic polymer latices used in connection with the present invention preferably have a coagulation temperature above 50°C and more preferably above 70°C. Coagulation may result from softening or melting of the thermoplastic polymer latices under the influence of heat.
  • a coagulation temperature of the thermoplastic hydrophobic polymer latices there is no specific upper limit to the coagulation temperature of the thermoplastic hydrophobic polymer latices, however the temperature should be sufficiently below the decomposition temperature of the polymer latices.
  • the coagulation temperature is at least 10°C below the temperature at which the decomposition of the polymer latices occurs.
  • hydrophobic thermoplastic polymer latices for use in connection with the present invention with a Tg above 80°C are preferably polyvinyl chloride, polyvinylidene chloride, polyacrylonitrile, polyvinyl carbazole etc., copolymers or mixtures thereof. Most preferably used are polystyrene, polymethylmethacrylate or copolymers thereof.
  • hydrophobic thermoplastic polymer latex When the hydrophobic thermoplastic polymer latex is dispersed in an aqueous medium without a binder said hydrophobic thermoplastic polymer latex preferably contains a water dispersing functional group such as an acid function.
  • Preferred hydrophobic thermoplastic polymer dispersed latices in such embodiment are polymers of therephthalic acid or isophthalic acid with ethylene diglycol or copolymers of therephthalic acid and isophthalic acid with ethylene diglycol, said polymers or copolymers comprising sulphoisophthalic acid in an amount between 0.5 and 5%.
  • the weight average molecular weight of the hydrophobic thermoplastic polymer may range from 5,000 to 1,000,000g/mol.
  • the hydrophobic thermoplastic polymer latex may have a particle size from 0.01 ⁇ m to 50 ⁇ m, more preferably between 0.05 ⁇ m and 10 ⁇ m and most preferably between 0.05 ⁇ m and 2 ⁇ m.
  • thermoplastic polymer latex is present as a dispersion in the aqueous coating liquid of the image forming layer and may be prepared by the methods disclosed in US-P-3,476,937. Another method especially suitable for preparing an aqueous dispersion of the thermoplastic polymer latex comprises:
  • the amount of hydrophobic thermoplastic polymer latex contained in the image forming layer when said layer contains a hydrophilic binder is preferably between 20% by weight and 90% by weight and more preferably between 25% by weight and 85% by weight and most preferably between 30% by weight and 80% by weight.
  • the second layer if containing a hydrophylic binder can also comprise crosslinking agents although this is not necessary.
  • Preferred crosslinking agents are low molecular weight substances comprising a methylol group such as for example melamine-formaldehyde resins, glycoluril-formaldehyde resins, thiourea-formaldehyde resins, guanamine-formaldehyde resins, benzoguanamine-formaldehyde resins.
  • a number of said melamine-formaldehyde resins and glycoluril-formaldehyde resins are commercially available under the trade names of CYMEL (Dyno Cyanamid Co., Ltd.) and NIKALAC (Sanwa Chemical Co., Ltd.)
  • the lithographic base having a hydrophilic surface can be an anodised aluminum.
  • a particularly preferred lithographic base having a hydrophilic surface is an electrochemically grained and anodised aluminum support.
  • an anodised aluminum support may be treated to improve the hydrophilic properties of its surface.
  • the aluminum support may be silicated by treating its surface with sodium silicate solution at elevated temperature, e.g. 95°C.
  • a phosphate treatment may be applied which involves treating the aluminum oxide surface with a phosphate solution that may further contain an inorganic fluoride.
  • the aluminum oxide surface may be rinsed with a citric acid or citrate solution.
  • This treatment may be carried out at room temperature or can be carried out at a slightly elevated temperature of about 30 to 50°C.
  • a further interesting treatment involves rinsing the aluminum oxide surface with a bicarbonate solution. Still further, the aluminum oxide surface may be treated with polyvinylphosphonic acid, polyvinylmethylphosphonic acid, phosphoric acid esters of polyvinyl alcohol, polyvinylsulphonic acid, polyvinylbenzenesulphonic acid, sulphuric acid esters of polyvinyl alcohol, and acetals of polyvinyl alcohols formed by reaction with a sulphonated aliphatic aldehyde. It is further evident that one or more of these post treatments may be carried out alone or in combination.
  • the lithographic base having a hydrophilic surface comprises a flexible support, such as e.g. paper or plastic film, provided with a cross-linked hydrophilic layer.
  • a particularly suitable cross-linked hydrophilic layer may be obtained from a hydrophilic binder cross-linked with a cross-linking agent such as formaldehyde, glyoxal, polyisocyanate or a hydrolysed tetraalkylorthosilicate. The latter is particularly preferred.
  • hydrophilic binder there may be used hydrophilic (co)polymers such as for example, homopolymers and copolymers of vinyl alcohol, acrylamide, methylol acrylamide, methylol methacrylamide, acrylic acid, methacrylic acid, hydroxyethyl acrylate, hydroxyethyl methacrylate or maleic anhydride/vinylmethylether copolymers.
  • the hydrophilicity of the (co)polymer or (co)polymer mixture used is preferably the same as or higher than the hydrophilicity of polyvinyl acetate hydrolyzed to at least an extent of 60 percent by weight, preferably 80 percent by weight.
  • the amount of crosslinking agent, in particular of tetraalkyl orthosilicate, is preferably at least 0.2 parts by weight per part by weight of hydrophilic binder, preferably between 0.5 and 5 parts by weight, more preferably between 1.0 parts by weight and 3 parts by weight.
  • a cross-linked hydrophilic layer in a lithographic base used in accordance with the present embodiment preferably also contains substances that increase the mechanical strength and the porosity of the layer.
  • colloidal silica may be used.
  • the colloidal silica employed may be in the form of any commercially available water-dispersion of colloidal silica for example having an average particle size up to 40 nm, e.g. 20 nm.
  • inert particles of larger size than the colloidal silica can be added e.g. silica prepared according to Stöber as described in J. Colloid and Interface Sci., Vol.
  • alumina particles or particles having an average diameter of at least 100 nm which are particles of titanium dioxide or other heavy metal oxides.
  • the thickness of a cross-linked hydrophilic layer in a lithographic base in accordance with this embodiment may vary in the range of 0.2 to 25 ⁇ m and is preferably 1 to 10 ⁇ m.
  • cross-linked hydrophilic layers for use in accordance with the present invention are disclosed in EP-A 601240, GB-P-1419512, FR-P-2300354, US-P-3971660, US-P-4284705 and EP-A 514490.
  • plastic film e.g. substrated polyethylene terephthalate film, cellulose acetate film, polystyrene film, polycarbonate film etc.
  • the plastic film support may be opaque or transparent.
  • the amount of silica in the adhesion improving layer is between 200 mg per m 2 and 750 mg per m 2 .
  • the ratio of silica to hydrophilic binder is preferably more than 1 and the surface area of the colloidal silica is preferably at least 300 m 2 per gram, more preferably at least 500 m 2 per gram.
  • An imaging element for use in accordance with the present invention comprises a hydrophobic first layer that is sensitive to heat having at least a hydrophobic polymer resin binder and a compound that is capable of converting light into heat, said layer having a decreased or increased capacity for being penetrated and/or solubilised by an aqueous developer upon exposure to actinic light.
  • the first layer includes a compound capable of converting light to heat.
  • Suitable compounds capable of converting light into heat are preferably infrared absorbing components although the wavelength of absorption is not of particular importance as long as the absorption of the compound used is in the wavelength range of the light source used for image-wise exposure.
  • Particularly useful compounds are for example dyes and in particular infrared dyes, carbon black, metal carbides, borides, nitrides, carbonitrides, bronze-structured oxides and oxides structurally related to the bronze family but lacking the A component e.g. WO 2.9 .
  • conductive polymer dispersion such as polypyrrole or polyaniline-based conductive polymer dispersions.
  • the lithographic performance and in particular the print endurance obtained depends on the heat-sensitivity of the imaging element. In this respect it has been found that carbon black yields very good and favorable results.
  • binder resin cellulose esters e.g. cellulose acetate, a copolymer of vinylidene chloride and acrylonitrile, poly(meth)acrylates, polyvinyl chloride, silicone resins etc. can be used.
  • binder resin is nitrocellulose.
  • a difference in the capacity of being penetrated and/or solubilised by the aqueous alkaline solution is generated upon image-wise exposure.
  • a difference in the capacity of the first layer to be penetrated and/or solubilised by a developing solution can be obtained by a thermally induced physical or chemical transformation.
  • thermally induced chemical transformations which generate a difference in the capacity of the layer for penetration and/or solubilisation by a developer are: laser induced change in polarity which increases the said capacity in the exposed areas and laser induced crosslinking which reduces the said capacity in the exposed areas.
  • the change in said capacity created upon laser exposure should be high enough to allow a complete clean-out without damaging and/or solubilising the resulting image upon development with an aqueous solution.
  • the imaged parts will be cleaned out during development without solubilising and/or damaging the non-imaged parts.
  • the non-imaged parts will be cleaned out during development without solubilising and/or damaging the imaged parts.
  • Preferred in the present invention is a heat sensitive element, wherein the increased capacity of the first layer to be penetrated and/or solubilized by a developing solution on exposure to actinic radiation is due to a selective ablative absorption of the first layer in the imaging areas.
  • the heat sensitive element according to the invention is first image-wise exposed to actinic light and then developed in an aqueous solution.
  • Actinic light is light that is absorbed by the compound converting light into heat.
  • Image-wise exposure in connection with the present invention is preferably an image-wise scanning exposure involving the use of a laser or L.E.D.. It is highly preferred in connection with the present invention to use a laser emitting in the infrared (IR) and/or near-infrared, i.e. emitting in the wavelength range 700-1500nm. Particularly preferred for use in connection with the present invention are laser diodes emitting in the near-infrared.
  • IR infrared
  • near-infrared i.e. emitting in the wavelength range 700-1500nm.
  • laser diodes emitting in the near-infrared are particularly preferred for use in connection with the present invention.
  • the development with the aqueous solution is preferably done within an interval of 5 to 120 seconds.
  • the aqueous solution has an alkaline pH when the hydrophilic binder of the second layer is a water insoluble, alkali soluble or swellable resin.
  • the aqueous solution has a neutral or an alkaline pH when the hydrophilic binder of the second layer is a water soluble resin. More preferably in this case water such as tap water is used.
  • the imaged parts of the first layer that were rendered more penetrable for the aqueous alkaline solution upon exposure and the parts of the underlying layer are cleaned-out whereby a positive working printing plate is obtained.
  • the laser imaged parts of the layer are rendered less penetrable for the aqueous alkaline solution upon image-wise exposure, thus the non-imaged parts of the top layer and the parts of the underlying layer are cleaned out.
  • the imaging element is first mounted on the printing cylinder of the printing press and then image-wise exposed directly on the press. Subsequent to exposure, the imaging element can be developed as described above.
  • the printing plate of the present invention can also be used in the printing process as a seamless sleeve printing plate.
  • the printing plate is soldered in a cylindrical form by means of a laser.
  • This cylindrical printing plate which has as diameter the diameter of the print cylinder is slided on the print cylinder instead of applying in a classical way a classically formed printing plate. More details on sleeves are given in "Grafisch Nieuws" ed. Keesing, 15, 1995, page 4 to 6.
  • the first layer may comprise a compound sensitive to visible light and/or UV-radiation to sensitise this layer to visible light and/or UV-radiation.
  • a gumming solution contains a water soluble (co)polymers for example synthetic homo- or copolymers such as polyvinylalcohol, a poly(meth)acrylic acid, a poly(meth)acrylamide, a polyhydroxyethyl(meth)acrylate, a polyvinylmethylether or natural binders such as gelatin, a polysaccharide such as e.g. dextran, pullulan, cellulose, arabic gum, alginic acid.e.g.
  • a gummed or ungummed developed plate at a temperature between 100°C and 230°C for a period of 40 minutes to 5 minutes.
  • the exposed and developed plates can be baked at a temperature of 230°C for 5 minutes, at a temperature of 150°C for 10 minutes or at a temperature of 120°C for 30 minutes.
  • a 0.20 mm thick aluminum foil was degreased by immersing the foil in an aqueous solution containing 5 g/l of sodium hydroxide at 50°C and rinsed with demineralized water.
  • the foil was then electrochemically grained using an alternating current in an aqueous solution containing 4 g/l of hydrochloric acid, 4 g/l of hydroboric acid and 5 g/l of aluminum ions at a temperature of 35°C and a current density of 1200 A/m 2 to form a surface topography with an average center-line roughness Ra of 0.5 ⁇ m.
  • the aluminum foil was then etched with an aqueous solution containing 300 g/l of sulfuric acid at 60°C for 180 seconds and rinsed with demineralized water at 25°C for 30 seconds.
  • the foil was subsequently subjected to anodic oxidation in an aqueous solution containing 200 g/l of sulfuric acid at a temperature of 45°C, a voltage of about 10 V and a current density of 150 A/m 2 for about 300 seconds to form an anodic oxidation film of 3.00 g/m 2 of Al 2 O 3 , then washed with demineralized water, posttreated with a solution containing polyvinylphosphonic acid( 2.2 g/m 2 ).
  • An imaging element according to the invention was prepared by first coating on the lithographic base from an aqueous medium a layer composed of 74.6% PMMA-latex, particle size 320 nm stabilised with Hostapal B, 18.7 % polyvinylpyrrolidone, 1.1% polyvinylalcohol and 5.6% of a Cu-phthalocyanine pigment dispersion in a dry thickness of 1g/m 2 . Thereon is coated a layer comprising 49.4% of a Carbon Black dispersion, 36.4 % nitrocellulose, 1% Solsperse 5000, 5% Solsperse 28000, 6.8% Cymel 301 and 1.4% p-Toluenesulphonic acid at a dry thickness of 1.5g/m 2 .
  • a material was prepared, without second layer; the toplayer being directly coated onto the lithographic base.
  • the obtained elements were heated for 2 days at 57°C and 34% relative humidity, to assure a good physical and chemical stability of the top layer.
  • Both materials were imaged with an external drum IR-laser imaging apparatus (NdYLF laser 1060 nm, drumspeed 8 m/s, at addresssabilities 5000 dpi and 200 dpi, power level in image plane 345 mW, spot size 10 ⁇ m), and develped in tap water (handdevelopment) and said plate was subsequently baked for 2 minutes at 200°C.
  • an external drum IR-laser imaging apparatus NaYLF laser 1060 nm, drumspeed 8 m/s, at adressabilities 5000 dpi and 200 dpi, power level in image plane 345 mW, spot size 10 ⁇ m
  • develped in tap water handdevelopment
  • This plate was used for printing on an Heidelberg GTO printing machine with a conventional ink (ABDick 1020) and fountain solution (Rotamatic), resulting in good prints, i.e. no ink uptake in the exposed parts and good ink-uptake in the non-exposed parts.
  • An imaging element according to the invention was produced by preparing the following coating composition and coating it to an hydrophilic aluminium base in an amount of 30 g/m 2 (wet coating amount) and drying it at 40°C.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Thermal Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Printing Plates And Materials Therefor (AREA)
  • Photosensitive Polymer And Photoresist Processing (AREA)
  • Thermal Transfer Or Thermal Recording In General (AREA)
  • Heat Sensitive Colour Forming Recording (AREA)

Claims (5)

  1. Elément de formation d'image thermosensible pour fabriquer des clichés d'impression lithographiques comprenant une base lithographique possédant une surface hydrophile, une première couche hydrophobe de résine polymère qui est sensible à la chaleur englobant au moins un liant hydrophobe et un composé qui est capable de transformer de la lumière en chaleur, ladite couche possédant une capacité réduite ou augmentée de pénétration et/ou de solubilisation par un révélateur aqueux lors d'une exposition à de la lumière actinique, caractérisé en ce que ledit élément de formation d'image comprend une deuxième couche située entre la première couche et la surface hydrophile, et englobant un latex polymère thermoplastique hydrophobe dispersé, ladite deuxième couche étant soluble ou apte à être dispersée dans une solution aqueuse.
  2. Elément de formation d'image thermosensible selon la revendication 1, dans lequel ledit latex polymère thermoplastique hydrophobe présent dans la deuxième couche est dispersé dans un liant hydrophile.
  3. Elément de formation d'image thermosensible selon la revendication 2, dans lequel ledit latex polymère thermoplastique hydrophobe présent dans la deuxième couche est dispersé dans un liant hydrophile hydrosoluble.
  4. Elément de formation d'image thermosensible selon la revendication 1, dans lequel ledit latex polymère thermoplastique hydrophobe présent dans la deuxième couche est dispersé en l'absence d'un liant.
  5. Elément de formation d'image thermosensible selon la revendication 4, dans lequel ledit latex polymère thermoplastique hydrophobe présent dans la deuxième couche contient un groupe fonctionnel rendant dispersible dans l'eau.
EP19970201559 1997-05-27 1997-05-27 Elément d'enregistrement thermosensible et procédé pour la fabrication de plaques lithographiques utilisant cet élément Expired - Lifetime EP0881094B1 (fr)

Priority Applications (4)

Application Number Priority Date Filing Date Title
DE1997603344 DE69703344T2 (de) 1997-05-27 1997-05-27 Wärmeempfindliches Aufzeichnungselement und Verfahren zur Herstellung von Flachdruckplatten damit
EP19970201559 EP0881094B1 (fr) 1997-05-27 1997-05-27 Elément d'enregistrement thermosensible et procédé pour la fabrication de plaques lithographiques utilisant cet élément
US09/073,435 US6106996A (en) 1997-05-27 1998-05-06 Heat sensitive imaging element and a method for producing lithographic plates therewith
JP10155391A JPH10329440A (ja) 1997-05-27 1998-05-21 感熱性画像形成要素及びそれを用いて平版印刷版を作製するための方法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19970201559 EP0881094B1 (fr) 1997-05-27 1997-05-27 Elément d'enregistrement thermosensible et procédé pour la fabrication de plaques lithographiques utilisant cet élément

Publications (2)

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EP0881094A1 EP0881094A1 (fr) 1998-12-02
EP0881094B1 true EP0881094B1 (fr) 2000-10-18

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Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6550387B1 (en) * 1999-08-31 2003-04-22 Agfa-Gevaert Processless thermal printing plate with well defined nanostructure
US6558787B1 (en) 1999-12-27 2003-05-06 Kodak Polychrome Graphics Llc Relation to manufacture of masks and electronic parts
JP2001337460A (ja) 2000-03-21 2001-12-07 Fuji Photo Film Co Ltd 平版印刷版用原版
DE602004010592T2 (de) * 2003-10-16 2008-12-11 Agfa Graphics N.V. Wärmeempfindlicher Vorläufer für eine Flachdruckplatte
EP1614539B1 (fr) * 2004-07-08 2008-09-17 Agfa Graphics N.V. Procédé de production d'une plaque d'impression lithographique
EP1614540B1 (fr) * 2004-07-08 2008-09-17 Agfa Graphics N.V. Procédé de production d'une plaque d'impression lithographique
US7354696B2 (en) 2004-07-08 2008-04-08 Agfa Graphics Nv Method for making a lithographic printing plate
US7425405B2 (en) 2004-07-08 2008-09-16 Agfa Graphics, N.V. Method for making a lithographic printing plate

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1177481A (en) * 1966-01-11 1970-01-14 Agfa Gevaert Nv Improved Heat-Sensitive Recording Material.
GB1208415A (en) * 1966-10-24 1970-10-14 Agfa Gevaert Nv Improvements relating to thermo-copying
JPS60201987A (ja) * 1984-03-26 1985-10-12 Ricoh Co Ltd 感熱又は感光感熱記録材料
US5493971A (en) * 1994-04-13 1996-02-27 Presstek, Inc. Laser-imageable printing members and methods for wet lithographic printing

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Publication number Publication date
EP0881094A1 (fr) 1998-12-02
JPH10329440A (ja) 1998-12-15
DE69703344D1 (de) 2000-11-23
DE69703344T2 (de) 2001-04-26

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