EP1048458B1 - Verfahren zur Herstellung einer lithographischen Druckplatte - Google Patents

Verfahren zur Herstellung einer lithographischen Druckplatte Download PDF

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Publication number
EP1048458B1
EP1048458B1 EP99201315A EP99201315A EP1048458B1 EP 1048458 B1 EP1048458 B1 EP 1048458B1 EP 99201315 A EP99201315 A EP 99201315A EP 99201315 A EP99201315 A EP 99201315A EP 1048458 B1 EP1048458 B1 EP 1048458B1
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EP
European Patent Office
Prior art keywords
cylindrical surface
donor material
image recording
press
cylinder
Prior art date
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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EP99201315A
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English (en)
French (fr)
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EP1048458A1 (de
Inventor
Eric C/O Agfa-Gevaert N.V. Verschueren
Joan C/O Agfa-Gevaert N.V. Vermeersch
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Agfa Gevaert NV
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Agfa Gevaert NV
Agfa Gevaert AG
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Publication date
Application filed by Agfa Gevaert NV, Agfa Gevaert AG filed Critical Agfa Gevaert NV
Priority to EP99201315A priority Critical patent/EP1048458B1/de
Priority to DE69907867T priority patent/DE69907867T2/de
Priority to US09/552,313 priority patent/US6190828B1/en
Priority to JP2000125422A priority patent/JP2000326652A/ja
Publication of EP1048458A1 publication Critical patent/EP1048458A1/de
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Publication of EP1048458B1 publication Critical patent/EP1048458B1/de
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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
    • B41M5/366—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 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
    • B41C1/1075—Mechanical aspects of on-press plate preparation
    • 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
    • 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
    • B41C2210/08—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
    • B41C2210/22—Preparation or type or constituents of the imaging layers, in relation to lithographic printing forme preparation characterised by organic non-macromolecular additives, e.g. dyes, UV-absorbers, plasticisers
    • 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

Definitions

  • the present invention relates to a method for making a lithographic printing master by on-press coating of an image recording composition.
  • Rotary printing presses use a so-called master such as a printing plate which is mounted on a cylinder of the printing press.
  • the master carries an image which is defined by the ink accepting areas of the printing surface and a print is obtained by applying ink to said surface and then transferring the ink from the master onto a substrate, which is typically a paper substrate.
  • ink as well as an aqueous fountain solution also called dampening liquid
  • lithographic surface which is referred to herein as lithographic surface and consists of oleophilic (or hydrophobic, i.e. ink accepting, water repelling) areas as well as hydrophilic (or oleophobic, i.e. water accepting, ink repelling) areas.
  • Printing masters are generally obtained by the so-called computer-to-film method wherein various pre-press steps such as typeface selection, scanning, colour separation, screening, trapping, layout and imposition are accomplished digitally and each colour selection is transferred to graphic arts film using an image-setter.
  • the film can be used as a mask for the exposure of an imaging material called plate precursor and after plate processing, a printing plate is obtained which can be used as a master.
  • EP-A 698 488 A computer-to-press method that is characterised by most of the above advantages has been disclosed in EP-A 698 488.
  • An oleophilic substance is image-wise transferred from a foil to a rotary press cylinder by melting said substance locally with a laser beam.
  • the strip-shaped transfer foil has a narrow width compared to the cylinder and is translated along a path which is parallel to the axis of the cylinder while being held in close contact with the surface of the cylinder so as to build up a complete image on that surface gradually.
  • this system is rather slow and requires a long downtime of the printing press, thereby reducing its productivity.
  • EP-A 400 595 describes a system for direct imaging including a form cylinder and means for selectively transferring heat meltable particles to the surface of the cylinder.
  • EP-A 368 180 describes a method for on-press imaging of a print cylinder by direct thermotransfer of the image from a donor material onto the print cylinder.
  • EP-A 802 457 describes an on-press coating method wherein an aqueous liquid, comprising a hydrophilic binder, a compound capable of converting light to heat and hydrophobic thermoplastic polymer particles, is coated on the plate cylinder so as to form a uniform, continuous layer thereon. Upon image-wise exposure, areas of the coated layer are converted into an hydrophobic phase, thereby defining the printing areas of the printing master.
  • the press run can be started immediately after exposure without any additional treatment because the layer is processed by interaction with the fountain and ink that are supplied to the cylinder during the press run. So the wet chemical processing of these materials is 'hidden' to the user and accomplished during the first runs of the printing press.
  • a problem associated with this method is that the wet coating step involves a risk of damaging or contaminating the optics and electronics of the integrated image-setter.
  • the method produces an insufficient coating quality, characterised by a low consistency and a high frequency of coating artefacts.
  • the quality of the wet-coating step can only be improved by installing a complex and sophisticated coating apparatus on the press.
  • This object is realised by the method defined in claim 1.
  • Fig. 1 shows a schematic illustration of a preferred embodiment according to the method of the present invention.
  • a donor material which comprises a support and a transfer layer is used to provide a hydrophilic cylindrical surface with an image recording layer.
  • the term "cylindrical surface” may also be referred to herein simply as "cylinder”.
  • the transfer layer comprises an image recording composition which is transferred from the donor material to the cylinder so as to form a continuous image recording layer. More specifically the transfer layer of the donor material is brought into physical contact with the cylinder and the donor material is conveyed continually along the cylindrical surface, thereby transferring the image recording composition from the donor material to the cylindrical surface.
  • the image recording composition used in the methods of the present invention comprises hydrophobic thermoplastic polymer particles dispersed in a hydrophilic binder and a compound capable of converting light to heat. It was quite unexpected to find that this composition is capable of being transferred simply by friction. Such friction can be generated by conveying the donor material along the cylindrical surface at a speed which is not equal to the rotational speed of the cylinder. According to an alternative embodiment, said image recording composition can also be transferred by moistening the cylindrical surface with an aqueous solution and conveying the donor material along the cylindrical surface without generating friction, i.e. by conveying the donor material along the cylindrical surface at a speed which is equal to the rotational speed of the cylinder.
  • the image recording composition is transferred by pre-moistening the cylindrical surface with an aqueous solution as well as by friction, i.e. by conveying the donor material along the moistened cylindrical surface at a speed which is not equal to the rotational speed of the cylinder.
  • the method of the present invention is distinguished from the prior art method of EP-A 698 488, in that the image recording composition is not transferred image-wise by local heating but is coated so as to form a uniform, continuous layer over the whole printing surface of the printing master. Since the width of the donor material is preferably equal to the width of the printing master, a single revolution of the cylindrical surface is sufficient to provide the whole surface of the printing master with a coating, thereby effectively reducing the downtime of the press necessary for coating. If the thickness of the coated layer that is obtained after a single revolution is not sufficient, additional revolutions may be necessary to obtain the desired coating thickness.
  • the image recording composition described herein is capable of forming a sufficient coating thickness after just a few revolutions.
  • the coated composition can be image-wise exposed to heat, thereby converting the exposed parts to hydrophobic, printing areas.
  • the unexposed parts are then removed during the first runs of the print job in a 'hidden' processing step by supplying fountain and/or ink. Since the cylindrical surface is a hydrophilic surface, the unexposed areas of the printing master are moistened during printing by the lithographic fountain solution. The hydrophobic exposed areas are ink accepting and define the printing areas of the printing master.
  • the method of the present invention is simple, more convenient, and produces consistent results and less coating artefacts.
  • the method of the present invention is especially suited to be carried out on-press because a dry coating step is used and, consequently, there is no increased risk of damaging or contaminating electronic or optical devices that are integrated in the press, such as an image-setter of a digital press.
  • the optional pre-moistening step and the processing step can be carried out by using regular fountain solution as an aqueous liquid, these steps neither prejudice the proper functioning of the electronic or optical devices of the press because during the press run such fountain liquids are supplied to the printing master anyhow.
  • the image recording composition is transferred to the cylinder by friction.
  • Said friction may be generated by conveying the donor material along the surface of the cylinder at a speed which is not equal to the rotational speed C of the cylinder.
  • the speed may be different in absolute magnitude as well as in direction, i.e. the speed at which the web of donor material is conveyed along the surface of the cylinder may be higher or slower relative to the rotation of the cylinder and may be opposite or acting in the same direction as the movement of the cylinder.
  • the term "not equal to C" also embraces the embodiment wherein the speed of the rotational movement of the cylinder and the speed at which the donor material is conveyed to the cylinder have an equal absolute magnitude but an opposite direction. C may also be equal to zero so that friction is generated by conveying the donor material along a stationary cylinder.
  • the donor material 1 is supplied to print cylinder 3 by unwinding a roller 2 of said material, contacting the material 1 with print cylinder 3 by contact rollers 4 and 5 and again winding the used material 1 on wind-up roller 6.
  • the supply roller 2 and the wind-up roller 6 are driven by means of electronically controllable motors, so that during the conveying of the donor material 1 the strip tension can be kept constant.
  • the transport direction and the rotational movement of the rollers 2 and 6 and print cylinder 3 are illustrated in Fig.1 by arrows (vectors).
  • the donor material 1 is conveyed to the print cylinder 3 at a speed C (vector 7) which is higher than the relative movement of the cylinder 3 and into a direction that is opposite to the revolution thereof (vector 8).
  • the transport of the donor material 1 can also occur in the other direction than shown in Fig. 1.
  • All the rollers shown in Fig.1 as well as the donor material 1 have substantially the same width (in the direction perpendicular to the plane of Fig.1) so that the whole surface of the print cylinder is provided with a coating after a few revolutions.
  • the speed of the donor material relative to the surface of the cylinder is sufficiently high, a single revolution suffices to obtain an adequate coating thickness.
  • the cylinder referred to above may be a plate cylinder of a rotary printing press, i.e. the transfer step can be carried out directly in the printing press.
  • the image recording composition may be transferred to a cylinder in a dedicated apparatus for coating a layer according to the method of the present invention and that cylinder may then be transported into a printing press either manually or automatically by a mechanism that couples said dedicated coating apparatus to the printing press.
  • This method enables to reduce to downtime of the press even more since the coating and even the exposure step can be carried out off-press while another print job is still running. After the press run, the printing master(s) are exchanged and a new print job can be started immediately.
  • the press cylinder is not directly coated with the image recording composition but a hydrophilic base material is mounted onto said press cylinder and the surface of that base material is coated with the image recording composition instead.
  • the base material can be e.g. a cylindrical seamless sleeve or a sheet that can be clamped around a press cylinder.
  • the base material can be e.g. a hydrophilic metal plate or a plastic sheet which has been provided with a hydrophilic layer.
  • a highly preferred base material is an electrochemically grained and anodised aluminium plate.
  • the anodised aluminium may be treated to improve the hydrophilic properties of its surface.
  • the aluminium 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 aluminium oxide surface with a phosphate solution that may further contain an inorganic fluoride.
  • the aluminium 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 aluminium oxide surface with a bicarbonate solution. It is further evident that one or more of these post treatments may be carried out alone or in combination.
  • Plastic materials which can be used as a base material are e.g. poly(ethylene terephthalate) or poly(ethylene naphthalate). These materials are preferably provided with a cross-linked hydrophilic layer.
  • a particularly suitable cross-linked hydrophilic layer may be obtained from a hydrophilic binder treated with a cross-linking agent such as formaldehyde, glyoxal, polyisocyanate or a hydrolysed tetra-alkylorthosilicate. 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 hydrolysed to at least an extent of 60 percent by weight, preferably 80 percent by weight.
  • the amount of crosslinking agent, in particular of tetra-alkyl 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.
  • the cross-linked hydrophilic layer of the base material 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 Stober as described in J. Colloid and Interface Sci., Vol. 26, 1968, pages 62 to 69 or 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 surface of the cross-linked hydrophilic layer is given a uniform rough texture consisting of microscopic hills and valleys, which serve as storage places for water in background areas.
  • the thickness of the cross-linked hydrophilic layer of the base material may vary in the range of 0.2 to 25 ⁇ m and is preferably 1 to 10 ⁇ m.
  • suitable 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.
  • the donor material comprises a support and a transfer layer which comprises the image recording composition.
  • a transfer layer which comprises the image recording composition.
  • the support of the donor material may be a metal foil, paper or a plastic film such as a poly(ethylene terephthalate) film, cellulose acetate film, polystyrene film, polycarbonate film etc.
  • the plastic film support may be opaque or transparent. It is particularly preferred to use a polyester film support.
  • the transfer layer of the donor material comprises a hydrophilic binder, for example synthetic homo or copolymers such as a poly(vinyl alcohol), a poly(meth)acrylic acid, a poly(meth)acrylamide, a poly(hydroxyethyl(meth)acrylate), a polyvinylmethylether or natural binders such as gelatine, a polysacharide such as e.g. dextran, pullulan, cellulose, arabic gum, alginic acid.
  • a hydrophilic binder for example synthetic homo or copolymers such as a poly(vinyl alcohol), a poly(meth)acrylic acid, a poly(meth)acrylamide, a poly(hydroxyethyl(meth)acrylate), a polyvinylmethylether or natural binders such as gelatine, a polysacharide such as e.g. dextran, pullulan, cellulose, arabic gum, alginic acid.
  • the transfer layer of the donor material also comprises hydrophobic thermoplastic polymer particles, preferably having a coagulation temperature above 35°C and more preferably above 50°C. Coagulation may result from softening or melting of the thermoplastic polymer particles under the influence of heat.
  • a coagulation temperature of the thermoplastic hydrophobic polymer particles there is no specific upper limit to the coagulation temperature of the thermoplastic hydrophobic polymer particles, however the temperature should be sufficiently below the decomposition of the polymer particles.
  • the coagulation temperature is at least 10°C below the temperature at which the decomposition of the polymer particles occurs.
  • hydrophobic polymer particles for use in connection with the present invention are e.g. polyethylene, polystyrene, poly(vinyl chloride), poly(methyl (meth)acrylate), poly(ethyl (meth)acrylate), poly(vinylidene chloride), polyacrylonitrile, poly(vinyl carbazole) etc. or copolymers thereof. Most preferably used is polystyrene.
  • the weight average molecular weight of the polymers may range from 5,000 to 1,000,000 g/mol.
  • the hydrophobic particles 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 50 nm and 80 nm.
  • the amount of hydrophobic thermoplastic polymer particles contained in the image recording layer is preferably between 20 and 95 wt.%, more preferably between 40 and 95% wt.% and most preferably between 70 and 90 wt.%.
  • the polymer particles are 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 particles comprises:
  • 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 transfer layer of the donor material may also contain other ingredients such as surfactants which can be anionic, cationic, non-ionic or amphoteric.
  • surfactants which can be anionic, cationic, non-ionic or amphoteric.
  • Perfluoro surfactants are preferred. Particularly preferred are non-ionic perfluoro surfactants. Said surfactants can be used alone or preferably in combination.
  • the imaging element is preferably image-wise exposed in heat mode by scanning with a laser or L.E.D. It is highly preferred to use a laser emitting in the infrared (IR), more particularly the near-infrared, i.e. emitting in the wavelength range 700-1500 nm. Near-infrared semiconductor (diode) lasers are especially preferred.
  • IR infrared
  • diode near-infrared semiconductor
  • the image recording layer is preferably processed by starting the print job.
  • the dampener rollers that supply fountain solution are first dropped on the cylinder, which has been coated with the image recording composition and, subsequently, the ink rollers are dropped. Generally, after about 10 revolutions of the cylinder the first clear and useful prints are obtained.
  • dampening liquids useful in the present invention there is no particular limitation and the known commercially available dampening liquids can be used.
  • Suitable dampening liquids are aqueous liquids generally having an acidic pH and comprising an alcohol such as isopropanol.
  • the surface of the cylinder Before the coating by transfer, the surface of the cylinder may be cleaned by the known manual or automatic procedures such as rubbing with a cloth, a cotton pad or a brush, air blowing, vacuuming, rinsing with a liquid by spraying or coating, or by using cleaning rollers, e.g. the devices known in the art for cleaning the blanket cylinder of an offset press.
  • a primer layer may be applied on the surface of the cylinder before coating the image recording composition. Said primer layer may be used to improve the adhesion of the image recording composition or to improve the hydrophilic character of the surface.
  • a 0.20 mm thick aluminium plate was degreased by immersion in an aqueous solution of 5 g/l of sodium hydroxide at 50 °C and subsequently rinsed with demineralised water.
  • the plate 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 aluminium ions at a temperature of 35 °C and a current density of 1200 A/m 2 so as to obtain a surface topography having an average center-line roughness (Ra) of 0.5 ⁇ m.
  • the aluminium plate was etched with an aqueous solution of 300 g/l of sulphuric acid at 60 °C during 180 seconds and subsequently rinsed with demineralised water at 25 °C during 30 seconds.
  • the plate was then subjected to anodic oxidation in an aqueous solution of 200 g/l of sulphuric acid at 45 °C, a voltage of about 10 V and a current density of 150 A/m 2 during 300 seconds so as to form an anodic oxidation film of 3.0 g/m 2 of aluminium oxide.
  • the plate was rinsed with demineralised water, post-treated with a solution containing a polyvinylphosphonic acid and aluminium trichloride, rinsed with demineralised water at 20 °C during 120 seconds and dried.
  • the above mentioned base material was mounted on the plate cylinder of a HeidelbergTM GTO46 offset printing press, which was provided with a device for friction-induced transfer as illustrated in Fig 1, with the proviso that just a single contact roller was present, thereby obtaining a line-type contact between the donor material and the base material.
  • the donor material was conveyed along the plate cylinder in the same direction as the rotation of the cylinder but at a reduced speed of 80% of the press speed (3400 prints/hour), while applying a pressure on the contact roller of 3 bar. After one run of the press, the contact was disrupted.
  • the printing member was image-wise exposed using an IR-diode laser having a wavelength of 830 nm and a power of 400 mJ/cm 2 . Processing was achieved by applying the dampening rollers during 5 revolutions and then starting the inking system. From the first prints, a very good print quality was obtained. A run length of 10 000 copies was obtained without any loss of print quality.
  • Example 2 The same base material, donor material and printing press was used as described in Example 1. However before contacting the donor material and the base material, the latter was moistened with the dampening system of the press by applying the dampening system during 3 revolution. In this example, the pressure on the contact roller was reduced to 0.6 bar. After 1 revolution, the transferred image recording layer was allowed to dry at ambient conditions of temperature and humidity. Finally the same imaging, processing and printing procedure was applied with comparable results as in Example 1.
  • Example 1 The same base material, donor material and printing press was used as described in Example 1.
  • the plate cylinder was additionally equipped with a freely driving adhesive cleaning roller, i.e. a TeknekTM cleaning head CH2, commercially available from Teknek LLC (USA).
  • a freely driving adhesive cleaning roller i.e. a TeknekTM cleaning head CH2
  • the press was run during 10 revolutions while the adhesion roller was in contact with the base material.
  • the same exposure and processing procedure as described in Example 1 was used.
  • the lithographic quality of the prints is very comparable to these obtained in Example 1 and 2.
  • the pre-cleaning step reduced the number of point defects, caused by dust that is adhered to the receiving material, to almost zero.
  • Example 1 The same base material, donor material and printing press was used as described in Example 1.
  • the plate cylinder was additionally equipped with a freely running rubber cleaning roller (Shore hardness 40), which was covered with a lint-free absorbing HytonTM cover, available from Veratec USA.
  • the press was run during 10 revolutions, wetting the plate by applying the dampening system and realising a contact between the covered rubber roller and the base material. Afterwards, the covered rubber roller was tilted away from the base material. After this cleaning step, the same exposure and processing procedure as described in Example 1 was used.
  • the lithographic quality of the prints is very comparable to these obtained in Example 1 and 2.
  • the pre-cleaning step reduced the number of point defects, caused by dust that is adhered to the receiving material, to almost zero.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Printing Plates And Materials Therefor (AREA)
  • Manufacture Or Reproduction Of Printing Formes (AREA)

Claims (10)

  1. Ein Verfahren zur Herstellung einer lithografischen Druckvorlage, wobei in den folgenden Stufen eine hydrophile zylindrische Oberfläche (3) mit einer durchgehenden Bildaufzeichnungsschicht bereitgestellt wird :
    ein Donormaterial (1), das einen Träger und eine eine bildaufzeichnende Zusammensetzung enthaltende Schicht enthält, wird in physikalischen Kontakt mit der zylindrischen Oberfläche (3) gebracht, und
    das Donormaterial (1) wird über die zylindrische Oberfläche (3) gefördert, wobei die bildaufzeichnende Zusammensetzung vom Donormaterial (1) auf die zylindrische Oberfläche (3) übertragen wird,
    dadurch gekennzeichnet, daß die bildaufzeichnende Zusammensetzung hydrophobe thermoplastische, in einem hydrophilen Bindemittel dispergierte polymere Teilchen und eine Licht in Wärme umwandelnde Verbindung enthält.
  2. Ein Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß die Übertragung der bildauf zeichnenden Zusammensetzung durch Reibung erhalten wird, wobei die Reibung durch
    Drehung der zylindrischen Oberfläche (3) bei einer Geschwindigkeit C, die Null sein kann, und
    Förderung des Donormaterials (1) über die zylindrische Oberfläche (3) bei einer Geschwindigkeit, die C nicht gleich ist, generiert wird.
  3. Ein Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß die zylindrische Oberfläche (3) mit einer wäßrigen Flüssigkeit benetzt wird, ehe das Donormaterial (1) in physikalischen Kontakt mit der zylindrischen Oberfläche (3) gebracht wird.
  4. Ein Verfahren nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß die zylindrische Oberfläche (3) gereinigt wird, ehe das Donormaterial (1) in physikalischen Kontakt mit der zylindrischen Oberfläche (3) gebracht wird.
  5. Ein Verfahren nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß das Donormaterial (1) ein bahnartiges Material ist, das über die zylindrische Oberfläche (3) gefördert wird, indem das Donormaterial (1) von einer Vorratsrolle abgewickelt und nach dem physikalischen Kontakt mit der zylindrischen Oberfläche (3) wieder auf eine Aufwickelrolle aufgewickelt wird.
  6. Ein Verfahren nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß die zylindrische Oberfläche (3) die Oberfläche eines auf einen Zylinder einer Rotationsdruckmaschine aufgespannten hydrophilen Trägermaterials ist.
  7. Ein Verfahren nach einem der vorstehenden Ansprüche, dadurch gekennzeichnet, daß die Breite des Donormaterials (1) der Breite der lithografischen Druckvorlage wesentlich gleich ist.
  8. Ein durch die nachstehenden Schritte gekennzeichnetes Verfahren zur Herstellung einer lithografischen Druckvorlage :
    (i) Bereitstellen einer hydrophilen zylindrischen Oberfläche (3) mit einer durchgehenden Bildaufzeichnungsschicht nach einem der vorstehenden Ansprüche,
    (ii) bildmäßige Belichtung der Bildauf zeichnungsschicht, und
    (iii) Entfernung der unbelichteten Bereiche der Bildaufzeichnungsschicht, indem der zylindrischen Oberfläche (3) Feuchtwasser oder Druckfarbe zugeführt werden.
  9. Ein Verfahren nach Anspruch 8, dadurch gekennzeichnet, daß die Bildaufzeichnungsschicht mit einem Infrarotlaser belichtet wird.
  10. Ein Verfahren nach Anspruch 8 oder 9, dadurch gekennzeichnet, daß die Stufen (i), (ii) und (iii) in einer Rotationsdruckpresse mit eingebautem Laserbelichter durchgeführt werden.
EP99201315A 1999-04-27 1999-04-27 Verfahren zur Herstellung einer lithographischen Druckplatte Expired - Lifetime EP1048458B1 (de)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP99201315A EP1048458B1 (de) 1999-04-27 1999-04-27 Verfahren zur Herstellung einer lithographischen Druckplatte
DE69907867T DE69907867T2 (de) 1999-04-27 1999-04-27 Verfahren zur Herstellung einer lithographischen Druckplatte
US09/552,313 US6190828B1 (en) 1999-04-27 2000-04-19 Method for making a lithographic printing master
JP2000125422A JP2000326652A (ja) 1999-04-27 2000-04-26 平版印刷マスターの作製方法

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EP99201315A EP1048458B1 (de) 1999-04-27 1999-04-27 Verfahren zur Herstellung einer lithographischen Druckplatte

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EP1356926B1 (de) * 2002-04-26 2008-01-16 Agfa Graphics N.V. Negativ-arbeitender thermischer Flachdruckplattenvorläufer, der einen Aluminiumträger mit einer glatten Oberfläche enthält
US6983694B2 (en) 2002-04-26 2006-01-10 Agfa Gevaert Negative-working thermal lithographic printing plate precursor comprising a smooth aluminum support
EP1614538B1 (de) * 2004-07-08 2009-03-04 Agfa Graphics N.V. Verfahren zur Herstellung einer negativarbeitenden, wärmeempfindlichen, lithographischen Druckplattenvorstufe
WO2006037716A1 (en) * 2004-10-01 2006-04-13 Agfa Graphics N.V. Method of making lithographic printing plates
DE102008029817A1 (de) * 2008-06-24 2009-12-31 Heidelberger Druckmaschinen Ag Verfahren zum Herstellen einer Bedruckstoff kontaktierenden Oberfläche

Citations (1)

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Publication number Priority date Publication date Assignee Title
EP0802457A1 (de) * 1996-04-16 1997-10-22 Agfa-Gevaert N.V. Herstellungs- und Bildaufzeichnungsverfahren für Flachdruckplatten

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Publication number Priority date Publication date Assignee Title
DE3837978A1 (de) * 1988-11-09 1990-05-10 Roland Man Druckmasch Verfahren zur bebilderung eines druckformzylinders
DE3917844C1 (de) * 1989-06-01 1990-10-31 Man Roland Druckmaschinen Ag, 6050 Offenbach, De
DE4430555C1 (de) * 1994-08-27 1996-04-04 Roland Man Druckmasch Verfahren und Vorrichtung zur Herstellung einer Druckform
EP0770495B1 (de) * 1995-10-24 2002-06-19 Agfa-Gevaert Verfahren zur Herstellung einer lithographischen Druckplatte mit auf der Druckpresse stattfindenden Entwicklung

Patent Citations (1)

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Publication number Priority date Publication date Assignee Title
EP0802457A1 (de) * 1996-04-16 1997-10-22 Agfa-Gevaert N.V. Herstellungs- und Bildaufzeichnungsverfahren für Flachdruckplatten

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