EP1520728A2 - Procédé de fabrication d'un support pour plaque lithographique - Google Patents

Procédé de fabrication d'un support pour plaque lithographique Download PDF

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Publication number
EP1520728A2
EP1520728A2 EP04023067A EP04023067A EP1520728A2 EP 1520728 A2 EP1520728 A2 EP 1520728A2 EP 04023067 A EP04023067 A EP 04023067A EP 04023067 A EP04023067 A EP 04023067A EP 1520728 A2 EP1520728 A2 EP 1520728A2
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EP
European Patent Office
Prior art keywords
aluminum alloy
melt
lithographic printing
support
treatment
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.)
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Application number
EP04023067A
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German (de)
English (en)
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EP1520728A3 (fr
Inventor
Hirokazu Sawada
Akio Uesugi
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Fujifilm Corp
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Fuji Photo Film Co Ltd
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Publication date
Application filed by Fuji Photo Film Co Ltd filed Critical Fuji Photo Film Co Ltd
Publication of EP1520728A2 publication Critical patent/EP1520728A2/fr
Publication of EP1520728A3 publication Critical patent/EP1520728A3/fr
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
    • B22D11/003—Aluminium alloys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
    • B41N1/00—Printing plates or foils; Materials therefor
    • B41N1/04—Printing plates or foils; Materials therefor metallic
    • B41N1/08—Printing plates or foils; Materials therefor metallic for lithographic printing
    • B41N1/083—Printing plates or foils; Materials therefor metallic for lithographic printing made of aluminium or aluminium alloys or having such surface layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
    • B41N3/00—Preparing for use and conserving printing surfaces
    • B41N3/03—Chemical or electrical pretreatment
    • B41N3/034—Chemical or electrical pretreatment characterised by the electrochemical treatment of the aluminum support, e.g. anodisation, electro-graining; Sealing of the anodised layer; Treatment of the anodic layer with inorganic compounds; Colouring of the anodic layer

Definitions

  • the present invention relates to a method of manufacturing a support for a lithographic printing plate using an aluminum alloy plate.
  • Aluminum alloy plate is generally produced by casting a slab from an aluminum alloy melt by a semi-continuous casting process, subjecting the slab to homogenizing heat treatment, then hot rolling, cold rolling and, if necessary, annealing.
  • various continuous casting processes have been proposed which use a moving mold to cast an aluminum alloy melt directly as a plate.
  • Continuous casting processes which use such a moving mold include processes that employ a moving mold in the form of a pair of belts, such as the Hazelett process and processes which employ a moving mold in the form of a pair of rolls, such as the Hunter process and the 3C process.
  • a pair of cooling rollers are tilted about 15° to the horizontal and the aluminum alloy plate is cast in an upwardly angled direction.
  • a pair of cooling rollers are arranged vertically and the aluminum alloy plate is cast in the horizontal direction.
  • the aluminum alloy melt (referred to hereinafter as "aluminum melt") is fed between a pair of cooling rollers by a melt feed nozzle, and solidification and rolling of the aluminum melt are carried out by the cooling rollers as a single operation.
  • the object of the present invention is to provide a method of manufacturing lithographic printing plate supports which are free of surface mottling.
  • Host crystals refers to a group of crystals among the crystal grains in the casting step which have a relatively similar crystal orientation.
  • the inventors have also found that, even in such a case, the surface mottling that has arisen can be reduced by increasing the total amount of electricity during the anode reaction in subsequent electrochemical graining treatment.
  • the inventors have learned as well that a total amount of electricity during the anode reaction in the electrochemical graining treatment which is too large diminishes the surface mottling reducing effect.
  • the inventors have completed a method of manufacturing a support for a lithographic printing plate of the present invention which keeps surface mottling from occurring by, in the course of graining treatment, setting the total amount of electricity during the anode reaction in the electrochemical graining treatment according to the amount of aluminum dissolution in the preceding alkali etching treatment, and by setting the total amount of electricity during the anode reaction in the electrochemical graining treatment within a specific range.
  • the present invention provides the following method of manufacturing a support for a lithographic printing plate.
  • the method of the present invention provides a support for a lithographic printing plate which is free of surface mottling.
  • an aluminum melt which has been adjusted to a predetermined composition is subjected to conventional cleaning treatment.
  • Cleaning treatment which is carried out to remove unnecessary gases such as hydrogen from the aluminum melt, involves flux treatment; degassing treatment using argon gas, chlorine gas or the like; filtering treatment using, for instance, what is referred to as a rigid media filter (e.g., ceramic tube filters, ceramic foam filters), a filter that employs a filter medium such as alumina flakes or alumina balls, or a glass cloth filter; or a combination of degassing treatment and filtering treatment.
  • a rigid media filter e.g., ceramic tube filters, ceramic foam filters
  • Cleaning treatment is not essential, but is preferably carried out to prevent defects due to foreign matter such as nonmetallic inclusions and oxides in the aluminum melt, and defects due to dissolved gases within the aluminum melt.
  • the feeding step which is carried out as needed, involves supplying the aluminum melt from a melting furnace to the melt feed nozzle through a flow channel. It is preferable here to have a stirrer provided in a recess formed in the base of the flow channel stir the aluminum melt in the vicinity of the recess.
  • stirring the aluminum melt just before it is supplied to the melt feed nozzle is advantageous for preventing stagnation of the aluminum melt and for preventing the settling and accumulation of large particles during stagnation. This is described more fully below.
  • FIG. 1 is a schematic diagram showing an exemplary casting arrangement from the melting furnace to the casting machine.
  • An aluminum melt 22 held in a melting furnace 12 is supplied via a flow channel 14 to a melt feed nozzle 16 in a casting machine 10.
  • a recess 30 is formed in the base of the flow channel 14 at an intermediate position thereon, and a gas discharging element 43 is provided in the recess 30 as the stirrer.
  • FIG. 2 is a schematic diagram showing an example of a recess provided with a stirrer.
  • a gas such as argon that does not react with the aluminum melt 22 is discharged as small bubbles 46 from a gas discharging element 43 which is made of ceramic or some other porous material and located within the recess 30, thereby agitating the aluminum melt 22 in the recess 30 and preventing stagnation from occurring.
  • FIG. 3 is a schematic diagram showing another example of a recess provided with a stirrer. As shown in FIG. 3, a gas such as argon that does not react with the aluminum melt 22 is discharged as small bubbles 46 from a rotor 45 within the recess 30, thereby agitating the aluminum melt 22 in the recess 30 and preventing stagnation from occurring.
  • a gas such as argon that does not react with the aluminum melt 22 is discharged as small bubbles 46 from a rotor 45 within the recess 30, thereby agitating the aluminum melt 22 in the recess 30 and preventing stagnation from occurring.
  • the aluminum melt is fed between a pair of cooling rollers by the melt feed nozzle and is rolled as it is being solidified by the pair of cooling rollers, forming an aluminum alloy plate.
  • the aluminum melt 22 is fed between a pair of cooling rollers 18 by the melt feed nozzle 16.
  • the aluminum melt 22 is rolled as it is being solidified by the cooling rollers 18, forming an aluminum alloy plate 36.
  • the resulting aluminum alloy plate 36 has a thickness of preferably 0.1 to 0.5 mm, although the thickness is generally set at 1 to 10 mm when the subsequently described rolling step is carried out.
  • FIG. 4 is a schematic diagram showing an example of the relative positions of the cooling rollers, the melt feed nozzle, the aluminum alloy plate, the aluminum melt and a melt meniscus.
  • the aluminum melt 22 passes through a melt feed nozzle 16 composed of a pair of nozzle plates 4a and 4b and side plates (not shown), and is fed between a pair of cooling rollers 18 that have been installed with a clearance C therebetween, thereby casting an aluminum alloy plate in the direction of the arrow a.
  • the aluminum melt 22 spreads vertically in the gap defined by top and bottom surfaces at a curvature corresponding to the nozzle outlet and the diameter of the cooling rollers, thereby forming a melt meniscus 3.
  • the cast aluminum alloy plate has a thickness t which is substantially equal to the clearance C between the cooling rollers 18 or is a value equivalent to the sum of the clearance C and elastic deformation by the casting machine and the aluminum alloy plate.
  • the cooling rollers prefferably have a circumferential speed V (m/min), the aluminum alloy plate to have a thickness t (m) and the cooling rollers to have a diameter D (m) which satisfy formula (2) below because in such a relation surface mottling does not readily arise.
  • FIGs. 11 and 12 are schematic diagrams showing examples of the shape of a melt feed nozzle and the relative positions of the nozzle and a cooling roller according to the prior art.
  • a nozzle 9a having an ordinary shape is used.
  • the nozzle 9a and a cooling roller 18 are disposed so as to be in mutual contact. In this case, it is difficult to bring only the tip T of the nozzle 9a into contact with the cooling roller 18.
  • a gap 11a arises between the tip T of the nozzle 9a and the surface of the cooling roller 18. This gap 11a causes the melt meniscus to change readily, which tends to encourage non-uniform growth of the crystal structure.
  • a nozzle of ordinary shape is used in FIG. 12 as well.
  • the nozzle 9a and the cooling roller 18 are disposed with a gap 11b therebetween and not allowed to touch.
  • the melt meniscus readily changes, encouraging non-uniform growth of the crystal structure.
  • the melt feed nozzle it is preferable for the melt feed nozzle to have an opening with both an outer edge that touches the cooling rollers and an outer periphery in which a relief has been recessed to avoid contact with the cooling rollers.
  • the tip of the melt feed nozzle is constantly in touch with the cooling rollers, increasing the stability of the melt at the nozzle tip, which is highly desirable.
  • FIG. 5 is a schematic diagram showing a preferred embodiment of the shape of the melt feed nozzle and the relative positions of the melt feed nozzle and a cooling roller.
  • FIG. 5 only the nozzle plate and cooling roller on the upper side of the nozzle are shown, but the same positional relationship exists between the nozzle plate and cooling roller on the lower side of the nozzle.
  • the outer edge of the melt feed nozzle 16 opening touches the cooling roller 18, and the outer periphery of the melt feed nozzle 16 opening has recessed therein a relief (chamfer) to avoid contact with the cooling roller 18. That is, only the tip T of the melt feed nozzle 16 touches the cooling roller 18.
  • the relief (chamfer) is preferably provided over the entire width of the melt feed nozzle 16.
  • melt feed nozzle If the melt feed nozzle is of inadequate strength, part of the melt feed nozzle may fail during casting. This will change the gap between the melt feed nozzle and the cooling rollers, leading in the same way as described above to surface mottling.
  • FIG. 13 is a schematic diagram showing an example in which the tip of the melt feed nozzle has failed.
  • the melt meniscus is generally located in a region like that shown in FIG. 4.
  • the melt meniscus changes in a region like that shown in FIG. 13.
  • the meniscus becomes unstable and the melt residence time at the melt meniscus changes, which tends to lead to crystal in homogeneities such as large crystals.
  • external causes include unstable solidification immediately after the start of casting, an abnormal rolling load, meander and waviness of the cast plate, and vibrations.
  • melt feed nozzle it is thus advantageous for at least part of the melt feed nozzle to be made of a heat-resistant material.
  • the heat-resistant material is preferably one having a flexural strength of at least 10 MPa.
  • Engineering-grade fine ceramics are desirable because they provide both heat resistance and strength. More specifically, ceramic materials which contain at least one material selected from the group consisting of ZrO 2 Al 2 O 3 , Si 3 N 4 , SiC, SiO 2 and aluminolithium silicate are preferred because of their strength and heat resistance. Of these materials, ones having a low thermal conductivity are desirable for avoiding unnecessary cooling of the aluminum alloy melt within the nozzle. From this standpoint, ZrO 2 , Al 2 O 3 and aluminolithium silicate are preferred. The use of aluminolithium silicate as a mixture with calcium silicate is preferable for lowering the thermal conductivity.
  • the melt feed nozzle may be made entirely of the above-described heat-resistant material.
  • a plurality of supporting members composed of a material having a higher flexural strength than the material making up the melt feed nozzle are disposed at intervals of up to 200 mm along the width of the nozzle and support the tip of the melt feed nozzle. This makes the tip harder to deform, reducing the likelihood of melt feed nozzle failure.
  • FIG. 6 is a schematic diagram showing an example of a melt feed nozzle having supporting members.
  • FIG. 6A is a side view
  • FIG. 6B is a top view.
  • the melt feed nozzle 16 is supported by supporting members 15a.
  • the supporting members 15a are composed of a material having a higher flexural strength than the material making up the melt feed nozzle 16.
  • the interval between the supporting members 15a should preferably be no more than 200. However, for each of the supporting members 15a to provide good support where it is located, an interval of at least 20 mm is preferred. Within this range, tip failure can be reliably prevented from occurring even when the melt feed nozzle 16 is made of a refractory material of relatively low strength (e.g., a flexural strength of less than 10 MPa), such as Marinite or calcium silicate.
  • the melt feed nozzle pre-coated, on the inside surface thereof that comes into contact with the aluminum alloy melt, with an aggregate particle-containing release agent.
  • the aggregate used as the aggregate particles is preferably boron nitride. It is preferable for the aggregate particles to have a particle size distribution characterized by a median diameter of 5 to 20 ⁇ m and a mode diameter of 4 to 12 ⁇ m.
  • the aluminum melt can be prevented from sticking to the inside surface of the melt feed nozzle and flow within the nozzle can be kept orderly, making it possible to prevent streak-like inhomogeneities in growth of the crystal structure.
  • the melt feed nozzle is preferably composed in part of a top plate member which contacts the aluminum alloy melt from above and a bottom plate member which contacts the aluminum alloy melt from below, each of which members is vertically movable.
  • the top plate member and the bottom plate members are each subjected to pressure by the aluminum alloy melt and thereby pushed against the adjoining cooling roller surface.
  • This arrangement places the tip of the melt feed nozzle and the cooling roller in constant contact, as a result of which the shape of the melt meniscus is held constant, thus making it possible to obtain a support for lithographic printing plates in which appearance defects are even further suppressed.
  • FIG. 7 is a schematic diagram showing an example of a melt feed nozzle having a tip with a movable construction.
  • FIG. 7A is a top view
  • FIG. 7B is a side view.
  • a top plate member 40 and a bottom plate member 42 are fixed with bolts 90 in such a way as to allow the tip of the top plate member 40 and the tip of the bottom plate member 42 to move a little in response to pressure by the aluminum melt.
  • the respective tips of the top plate member 40 and the bottom plate member 42 can thus be brought into contact with the cooling rolls under pressure by the aluminum melt.
  • FIG. 8 is a schematic diagram showing another example of a melt feed nozzle having a tip with a movable construction.
  • FIG. 8A is a top view
  • FIG. 8B is a side view.
  • a top plate member 40 and a bottom plate member 42 are fixed with pins 92 in such a way as to allow the tip of the top plate member 40 and the tip of the bottom plate member 42 to pivot a little about the respective pins 92 in response to pressure by the aluminum melt.
  • the respective tips of the top plate member 40 and the bottom plate member 42 can thus be brought into contact with the cooling rolls under pressure by the aluminum melt.
  • the aluminum alloy plate is cold rolled to a desired thickness.
  • Cold rolling further reduces the thickness of the aluminum alloy plate obtained in the casting step.
  • FIG. 9 is a schematic diagram showing an example of a cold rolling mill that may be used to cold roll the cast aluminum alloy plate.
  • the cold rolling mill 50 shown in FIG. 9 carries out cold rolling by using a pair of cold-rolling rollers 56, each of which is rotated by a supporting roller 58, to apply pressure to an aluminum alloy plate 36 which travels between a delivery coil 52 and a take-up coil 54.
  • This rolling step is advantageous for bringing the aluminum alloy plate to a final thickness of 0.1 to 0.5 mm suitable for use as a support for lithographic printing plates.
  • the finished aluminum alloy plate may be subjected to a straightening step which improves flatness by means of a straightening machine such as a roller leveler or a tension leveler.
  • a slitting step in which the plate is passed through a slitter line is also generally carried out to cut the plate to a predetermined width.
  • FIG. 10 is a schematic diagram showing an example of a straightening machine.
  • the straightening machine 70 shown in FIG. 10 improves the flatness of an aluminum alloy plate 36 traveling between a delivery coil 82 and a take-up coil 84 while applying tension with a leveler 80 that includes work rolls 86.
  • the plate is then cut to a predetermined width with a slitter 88.
  • the surface of the aluminum alloy plate obtained from the previous steps is subjected to graining treatment which includes at least alkali etching treatment followed by electrochemical graining treatment, thereby giving a support for a lithographic printing plate.
  • the inventors have found that by establishing a specific relationship between the amount of aluminum dissolved in alkali etching treatment and the total amount of electricity during the anode reaction in electrochemical graining treatment, a uniform crystal structure can be achieved even after graining treatment. Moreover, in practicing the present invention, mottling can be suppressed even further by establishing a specific relationship between the amount of aluminum dissolved in alkali etching treatment and the total amount of electricity during the anode reaction in electrochemical graining treatment and using in combination with this any of the various methods for the suppression of mottling described above in connection with the casting step.
  • Graining treatment generally consists of one or a combination of two or more of the followings: mechanical graining, chemical graining and electrochemical graining.
  • graining treatment includes both alkali etching treatment and subsequent electrochemical graining treatment, although it may also include other types of graining treatment.
  • the various types of treatments that may be included in graining treatment are described below.
  • Mechanical graining is carried out to give the surface of the aluminum alloy plate an average surface roughness of 0.35 to 1.0 ⁇ m.
  • Methods such as those described in JP 6-135175 A and JP 50-40047 B may be used to carry out mechanical graining.
  • This type of treatment is preferably carried out before electrochemical graining (before the first electrochemical graining treatment if electrochemical graining is carried out a plurality of times).
  • Mechanical graining preferably involves the use of a rotating nylon brush roll having a bristle diameter of 0.2 to 0.9 mm and an abrasive compound that is supplied as a slurry to the surface of the aluminum alloy plate.
  • Use may also be made of a technique that involves blowing the slurry onto the surface of the plate, a technique that involves the use of a wire brush, or a technique in which the pattern-indented surface shape of a reduction roll is transferred to the aluminum alloy plate. The last of these methods is better than methods which use a brush or abrasive compound because there is less tendency for locally deep areas to form.
  • alkali etching treatment In chemical etching treatment, the surface of the aluminum alloy plate is chemically etched in an alkaline or acidic aqueous solution.
  • alkali etching treatment having an excellent dissolution efficiency is carried out using an alkaline aqueous solution.
  • a known method may be used to carry out alkali etching treatment.
  • alkali etching treatment is carried out before the first electrochemical graining treatment.
  • Alkali etching treatment is carried out to dissolve the uneven edges that form on the surface of the plate during mechanical graining treatment, so as to obtain a smoothly undulating surface. As a result, lithographic printing plates of excellent scumming resistance can be obtained.
  • alkali etching treatment is used to remove foreign matter such as rolling oils remaining on the surface of the aluminum alloy plate.
  • alkaline aqueous solutions that may be used in alkali etching treatment include aqueous solutions containing one or more of the followings: sodium hydroxide, sodium carbonate, sodium aluminate, sodium metasilicate, sodium phosphate, potassium hydroxide and lithium hydroxide.
  • An aqueous solution composed mainly of sodium hydroxide is especially preferred.
  • the alkaline aqueous solution may contain 0.5 to 10 wt% of aluminum and also alloying ingredients present in the aluminum alloy plate.
  • the alkaline aqueous solution has a concentration of preferably 1 to 50 wt%, and more preferably 1 to 30 wt%.
  • alkali etching treatment for 1 to 120 seconds, and preferably 2 to 60 seconds, at an alkaline aqueous solution temperature in a range of 20 to 100°C, and preferably 40 to 80°C.
  • the amount of aluminum dissolution in alkali etching treatment following mechanical graining treatment is preferably 1 to 20 g/m 2 at the surface on the side of the aluminum alloy plate subjected to graining treatment. Excessive alkali etching treatment is undesirable because mottling due to host crystals present within the aluminum alloy plate readily arises.
  • the amount of aluminum dissolution is preferably 1 to 13 g/m 2 , and more preferably 2 to 13 g/m 2 .
  • the amount of aluminum dissolution is 1 to 6 g/m 2 at the surface of the aluminum alloy plate on the side that is subjected to graining treatment.
  • the amount of aluminum dissolution at the surface of the aluminum alloy plate on the side where graining treatment is performed be at least 1 g/m 2 , impurities near the surface layer of the aluminum alloy plate can be completely removed, enabling uniform electrochemical graining treatment to be carried out.
  • the amount of aluminum dissolution at the surface of the aluminum alloy plate on the side that is not subjected to graining treatment, i.e., the back side is at least 1 g/m 2 .
  • Electrochemical graining is a treatment in which an alternating current or a direct current is passed through the aluminum alloy plate as the electrode in an acidic aqueous solution so as to electrochemically grain the surface of the plate. Electrochemical graining may be carried out using a method known to the art.
  • Electrochemical graining is carried out with the aim of forming crater-like or honeycomb-like pits having an average diameter of about 0.05 to 20 ⁇ m to a surface area ratio of 30 to 100% on the surface of the aluminum alloy plate. Electrochemical graining treatment enhances the press life and the scumming resistance in non-image areas of the lithographic printing plate.
  • Any acidic aqueous solution used in conventional electrochemical graining involving the use of direct current or alternating current may be employed here in electrochemical graining treatment, although the use of an acidic aqueous solution composed mainly of nitric acid or an acidic aqueous solution composed mainly of hydrochloric acid is preferred.
  • a nitric acid-containing acidic aqueous solution prepared by adding to a nitric acid solution having a nitric acid concentration of 1 to 100 g/L at least one nitrate compound having nitrate ions, such as aluminum nitrate, sodium nitrate or ammonium nitrate, to a concentration of from 0.01 g/L to saturation.
  • the nitric acid-containing acidic aqueous solution may also contain, dissolved therein, metals which are present in the aluminum alloy, such as iron, copper, manganese, nickel, titanium, magnesium and silicon.
  • a hydrochloric acid-containing acidic aqueous solution prepared by adding to a hydrochloric acid solution having a hydrochloric acid concentration of 1 to 100 g/L at least one chloride compound containing chloride ions, such as aluminum chloride, sodium chloride or ammonium chloride, to a concentration of from 0.01 g/L to saturation.
  • the acidic aqueous solution composed mainly of hydrochloric acid may also contain, dissolved therein, metals which are present in the aluminum alloy, such as iron, copper, manganese, nickel, titanium, magnesium and silicon.
  • electrochemical graining treatment is performed in such a way that the surface of the aluminum alloy plate subjected to graining treatment undergoes an amount of aluminum dissolution X per square meter (g/m 2 ) during alkali etching treatment and has a total amount of electricity Y per square decimeter (C/dm 2 ) applied thereto during the anode reaction in electrochemical graining treatment which satisfy formula (1) below.
  • mottling of the support for lithographic printing plate caused by host crystals that form during casting can be prevented by making the total amount of electricity during the anode reaction in electrochemical graining large. If the total amount of electricity during the anode reaction in electrochemical graining is too large, the surface mottling reducing effect diminishes. However, by having this value fall within the above range, a larger effect can be achieved.
  • the total amount of electricity during the anode reaction at the surface on the side of the aluminum alloy plate subjected to graining treatment in electrochemical graining is preferably at least 50 C/dm 2 . Within this range, mottling at the surface of the support for lithographic printing plate can be more reliably suppressed.
  • the average current density during the anode reaction in electrochemical graining treatment is preferably at least 5 A /dm 2 . Within this range, pit dispersibility in electrochemical graining is good. Electropolishing Treatment or Second Chemical Etching Treatment:
  • the amount of dissolution from the aluminum alloy plate in electropolishing treatment or the second chemical etching treatment is preferably 0.05 to 5 g/m 2 , and more preferably 0.1 to 3 g/m 2 .
  • the amount of aluminum dissolution during the first alkali etching treatment must satisfy above formula (1), but no particular limitation is imposed on the amount of aluminum dissolution in the second alkali etching treatment.
  • Anodizing treatment is performed to increase the wear resistance at the surface of the aluminum alloy plate.
  • Anodizing treatment can be carried out by any method used in the art to which the invention relates.
  • an anodized layer can be formed on the surface of the aluminum alloy plate by passing a current through the plate as the anode in a solution having a sulfuric acid concentration of 50 to 300 g/L and having an aluminum concentration of up to 5 wt%.
  • the solution used in anodizing treatment is not subject to any particular limitation so long as it can form an oxide layer on the aluminum alloy plate.
  • Illustrative examples include solutions of sulfuric acid, phosphoric acid, oxalic acid, chromic acid, or mixtures thereof.
  • the electrolyte concentration may be selected as appropriate for the type of electrolyte.
  • the anodizing treatment conditions vary empirically according to the electrolytic solution used, although it is generally suitable for the solution to have a concentration of 1 to 80 wt% and a temperature of 5 to 70°C, and for the current density to be 1 to 60 A/dm 2 , the voltage to be 1 to 100 V, and the electrolysis time to be 10 to 300 seconds. These conditions are adjusted to obtain the desired anodized layer weight.
  • Sealing treatment is carried out to seal micropore openings in the anodized layer that has been formed by anodizing treatment.
  • sealing treatment examples include a method in which the aluminum alloy plate is immersed in hot water and an aqueous solution containing an inorganic or organic salt, and a method in which the aluminum alloy plate is passed through a steam bath.
  • Hydrophilizing treatment involves rendering the surface of the support for lithographic printing plate hydrophilic.
  • hydrophilizing treatment examples include the alkali metal silicate (e.g., aqueous sodium silicate solution) methods described in US 2,714,066, US 3,181,461, US 3,280,734 and US 3,902,734.
  • alkali metal silicate e.g., aqueous sodium silicate solution
  • the aluminum alloy plate is immersed, or subjected to electrolysis, in an aqueous solution of sodium silicate.
  • the support for lithographic printing plate obtained as described above is then provided with an image recording layer, thereby giving a presensitized plate.
  • the image recording layer is not subject to any particular limitation. Any image recording layer known to the art may be used. Illustrative examples include prior-art photosensitive layers that are combined with lith film and exposed to light, thermal-type heat-sensitive layers capable of direct image formation using a laser, non-treatment type image recording layers which do not need to be developed following laser exposure, and image recording layers which can be developed on press following laser exposure.
  • the image recording layer may be either negative-working or positive-working.
  • thermo-type heat-sensitive layers that may be used include the image recording layers mentioned in JP 2003-21906 A.
  • an undercoat (intermediate layer) may be provided, if necessary. Any undercoat known to the art may be used. Specific examples include those mentioned in JP 6-135175 A.
  • the presensitized plate obtained by providing an image recording layer on the support for lithographic printing plate is subjected to platemaking treatment according to the type of image recording layer, thereby forming a lithographic printing plate which can be furnished for printing.
  • Lithographic printing plates made using supports obtained by the method of the invention have an excellent printing performance.
  • Supports for lithographic printing plates were produced by carrying out a feeding step, a casting step, a rolling step and a graining treatment step in the manner described below.
  • an aluminum alloy plate was continuously cast using the arrangement shown in FIG. 1.
  • aluminum melt that had been subjected to cleaning treatment was supplied from a melting furnace to a melt feed nozzle through a flow channel having a stirrer within a recess as shown in FIG. 3.
  • the aluminum melt was fed by the melt feed nozzle between a pair of cooling rollers, and was formed into an aluminum alloy plate by rolling the melt as it was being solidified with the pair of cooling rollers.
  • the circumferential speed V of the cooling rollers and the thickness t of the aluminum alloy plate are given in Table 1.
  • the diameter D of the cooling rollers was 0.9 m.
  • Table 1 indicates whether or not the outer edge of the melt feed nozzle opening was in contact with the cooling rollers.
  • a melt feed nozzle like that shown in FIG. 7 which consisted in part of a top plate member that contacted the aluminum melt from above and a bottom plate member that contacted the aluminum melt from below, both plate members being vertically movable. In this nozzle, the top and bottom plate member were each subjected to pressure by the aluminum melt and thereby pushed against the surface of the adjoining cooling roller.
  • the outer periphery of the melt feed nozzle opening had a relief recessed therein to avoid contact with the cooling rollers.
  • the material making up the melt feed nozzle is shown in Table 1.
  • the meanings of the symbols shown in Table 1 are explained in Table 2.
  • Table 1 indicates whether the melt feed nozzle had supporting members. In cases where the nozzle had supporting members, a plurality of such members were disposed at intervals of 180 mm in the width direction.
  • the cast aluminum alloy plate was cold rolled to a thickness of 2 mm, after which it was heat treated at 550°C for 10 hours, then was again cold rolled, this time to a final thickness of 0.3 mm.
  • the cold-rolled aluminum alloy plate was subjected to graining treatment as described below, giving a support for a lithographic printing plate in each example.
  • alkali etching treatment was carried out using an aqueous solution of sodium hydroxide.
  • the amount of aluminum dissolution was set to different levels by varying the concentration and temperature of the aqueous solution and the treatment time.
  • the amount of aluminum dissolution X at the surface on the side subjected to graining treatment and the amount of aluminum dissolution on the back side are each indicated in Table 1.
  • electrochemical graining treatment was carried out using an alternating current power supply and an aqueous solution of nitric acid.
  • the total amount of electricity Y during the anode reaction in electrochemical graining treatment is shown in Table 1.
  • the average current density during the anode reaction in electrochemical graining treatment was 20 A/dm 2 .
  • alkali etching treatment was carried out using an aqueous solution of sodium hydroxide.
  • the amount of aluminum dissolution at the surface on the side subjected to graining treatment was set at 1 g/m 2 .
  • desmutting treatment was carried out using a 170 g/L aqueous sulfuric acid solution.
  • Anodizing treatment was then carried out in a 170 g/L aqueous sulfuric acid solution such as to provide an anodized layer having a weight of 2.7 g/m 2 , thereby giving a support for a lithographic printing plate.
  • Melt feed nozzle material Type of material Flexural strength (MPa) 1 calcium silicate 9 2 aluminolithium silicate + calcium silicate 100 Release agent Median diameter ( ⁇ m) Mode diameter ( ⁇ m) Main component A 6.5 10.0 boron nitride B 1.5 1.5 zirconium oxide
  • mottling refers to the existence of areas on the surface of the support for lithographic printing plate where the glossiness or color tone differs from that in surrounding areas.
  • the mottling evaluation results obtained are shown in Table 4.
  • “occurred” signifies that mottling clearly occurred in one or more of the three specimens obtained in a particular example
  • “slight” signifies that mottling occurred but was of such a slight degree as to be of no concern
  • “did not occur” signifies that no mottling whatsoever was observed.
  • the surface quality of the support for lithographic printing plate was visually examined and rated on a scale of 1 to 6, based collectively on three surface characteristics of the support for lithographic printing plate: roughness, streaking and mottling.
  • a rating of 6 represents an excellent surface quality
  • 5 represents a good surface quality
  • 4 indicates a surface quality that is acceptable for practical purposes
  • 3 indicates a surface quality that is unacceptable for practical purposes
  • 2 signifies a poor surface quality
  • 1 signifies a very poor surface quality.
  • the rating shown in Table 4 for each example was the worst rating obtained for the three specimens in that example.
  • a surface quality stability rating of 3 indicates that all three specimens produced in a particular example had the same surface quality rating, a stability rating of 2 indicates that two different surface quality ratings were obtained among the three specimens, and a stability rating of 1 indicates that three different surface quality ratings were obtained.
  • the production stability was rated based on whether, in the casting step, an aluminum alloy plate could be stably cast without anomalies occurring thereon. For the three specimens obtained in each example, a rating of 1 was assigned when casting was stopped due to the occurrence of anomalies in the production of at least one specimen, a rating of 2 was assigned when casting was not stopped but anomalies appeared in at least one of the specimens, and a rating of 3 was assigned when no anomalies appeared in any of the specimens.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Printing Plates And Materials Therefor (AREA)
  • Continuous Casting (AREA)
  • ing And Chemical Polishing (AREA)
  • Photosensitive Polymer And Photoresist Processing (AREA)
  • Materials For Photolithography (AREA)
EP04023067A 2003-09-30 2004-09-28 Procédé de fabrication d'un support pour plaque lithographique Withdrawn EP1520728A3 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2003341425 2003-09-30
JP2003341425A JP2005105366A (ja) 2003-09-30 2003-09-30 平版印刷版用支持体の製造方法

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EP1520728A2 true EP1520728A2 (fr) 2005-04-06
EP1520728A3 EP1520728A3 (fr) 2005-09-07

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8338073B2 (en) 2005-07-14 2012-12-25 Fujifilm Corporation Lithographic printing plate support, method of manufacturing the same, and presensitized plate
CN101332494B (zh) * 2007-06-29 2013-04-10 富士胶片株式会社 平版印刷版用铝合金带的制造方法和制造设备
CN109261920A (zh) * 2018-10-26 2019-01-25 中冶连铸技术工程有限责任公司 小方坯连铸单辊压下方法和设备

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4607692B2 (ja) * 2005-07-14 2011-01-05 富士フイルム株式会社 平版印刷版用支持体の製造方法
JP5247011B2 (ja) * 2005-08-12 2013-07-24 富士フイルム株式会社 平版印刷版用支持体および平版印刷版原版
CN109158560B (zh) * 2018-10-18 2023-09-29 山东钢铁股份有限公司 复合板材的双辊连铸生产系统及生产方法

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US2790216A (en) 1955-06-20 1957-04-30 Hunter Eng Co Method and apparatus for the continuous casting of metal
US3902734A (en) 1974-03-14 1975-09-02 Twm Mfg Co Frames for axle suspension systems
JPS5115968B2 (fr) 1971-12-01 1976-05-20
JPS5189827A (fr) 1974-12-23 1976-08-06
JPS58209449A (ja) 1982-05-31 1983-12-06 Mitsubishi Keikinzoku Kogyo Kk アルミニウム合金連続鋳造板の製造方法
US4689272A (en) 1984-02-21 1987-08-25 Hoechst Aktiengesellschaft Process for a two-stage hydrophilizing post-treatment of aluminum oxide layers with aqueous solutions and use thereof in the manufacture of supports for offset printing plates
JP2002143988A (ja) 2000-11-14 2002-05-21 Fuji Photo Film Co Ltd 平版印刷版用支持体の製造方法及び製造装置

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EP0615801B1 (fr) * 1993-03-09 1999-06-02 Fuji Photo Film Co., Ltd. Méthode pour fabriquer un support d'une plaque d'impression à plat
JP3580469B2 (ja) * 1998-01-07 2004-10-20 富士写真フイルム株式会社 平版印刷版用支持体の製造方法
JP3994426B2 (ja) * 1998-07-13 2007-10-17 富士フイルム株式会社 アルミニウムの連続鋳造圧延装置及びその方法
JP3962849B2 (ja) * 1998-10-14 2007-08-22 富士フイルム株式会社 平版印刷版用支持体の製造装置

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2790216A (en) 1955-06-20 1957-04-30 Hunter Eng Co Method and apparatus for the continuous casting of metal
JPS5115968B2 (fr) 1971-12-01 1976-05-20
US3902734A (en) 1974-03-14 1975-09-02 Twm Mfg Co Frames for axle suspension systems
JPS5189827A (fr) 1974-12-23 1976-08-06
JPS58209449A (ja) 1982-05-31 1983-12-06 Mitsubishi Keikinzoku Kogyo Kk アルミニウム合金連続鋳造板の製造方法
US4689272A (en) 1984-02-21 1987-08-25 Hoechst Aktiengesellschaft Process for a two-stage hydrophilizing post-treatment of aluminum oxide layers with aqueous solutions and use thereof in the manufacture of supports for offset printing plates
JP2002143988A (ja) 2000-11-14 2002-05-21 Fuji Photo Film Co Ltd 平版印刷版用支持体の製造方法及び製造装置

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8338073B2 (en) 2005-07-14 2012-12-25 Fujifilm Corporation Lithographic printing plate support, method of manufacturing the same, and presensitized plate
CN101332494B (zh) * 2007-06-29 2013-04-10 富士胶片株式会社 平版印刷版用铝合金带的制造方法和制造设备
CN109261920A (zh) * 2018-10-26 2019-01-25 中冶连铸技术工程有限责任公司 小方坯连铸单辊压下方法和设备

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