EP2206019A2 - Method of producing a relief image arrangement usable in particular in the field of flexography and arrangement produced according to this method. - Google Patents

Method of producing a relief image arrangement usable in particular in the field of flexography and arrangement produced according to this method.

Info

Publication number
EP2206019A2
EP2206019A2 EP08842022A EP08842022A EP2206019A2 EP 2206019 A2 EP2206019 A2 EP 2206019A2 EP 08842022 A EP08842022 A EP 08842022A EP 08842022 A EP08842022 A EP 08842022A EP 2206019 A2 EP2206019 A2 EP 2206019A2
Authority
EP
European Patent Office
Prior art keywords
image
arrangement
relief
layer
support
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.)
Withdrawn
Application number
EP08842022A
Other languages
German (de)
French (fr)
Inventor
Dominique Bertrand
Chouaib Boukaftane
Christian Grab
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
MacDermid Graphics Solutions Europe SAS
Original Assignee
MacDermid Printing Solutions Europe SAS
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by MacDermid Printing Solutions Europe SAS filed Critical MacDermid Printing Solutions Europe SAS
Publication of EP2206019A2 publication Critical patent/EP2206019A2/en
Withdrawn legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/20—Exposure; Apparatus therefor
    • G03F7/2002—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image
    • G03F7/2012—Exposure; Apparatus therefor with visible light or UV light, through an original having an opaque pattern on a transparent support, e.g. film printing, projection printing; by reflection of visible or UV light from an original such as a printed image using liquid photohardening compositions, e.g. for the production of reliefs such as flexographic plates or stamps
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/20—Exposure; Apparatus therefor
    • G03F7/2022—Multi-step exposure, e.g. hybrid; backside exposure; blanket exposure, e.g. for image reversal; edge exposure, e.g. for edge bead removal; corrective exposure
    • G03F7/203—Multi-step exposure, e.g. hybrid; backside exposure; blanket exposure, e.g. for image reversal; edge exposure, e.g. for edge bead removal; corrective exposure comprising an imagewise exposure to electromagnetic radiation or corpuscular radiation
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/20—Exposure; Apparatus therefor
    • G03F7/2051—Exposure without an original mask, e.g. using a programmed deflection of a point source, by scanning, by drawing with a light beam, using an addressed light or corpuscular source
    • G03F7/2053—Exposure without an original mask, e.g. using a programmed deflection of a point source, by scanning, by drawing with a light beam, using an addressed light or corpuscular source using a laser
    • G03F7/2055—Exposure without an original mask, e.g. using a programmed deflection of a point source, by scanning, by drawing with a light beam, using an addressed light or corpuscular source using a laser for the production of printing plates; Exposure of liquid photohardening compositions

Definitions

  • the invention relates to a method for producing a relief image arrangement that can be used in particular in the field of flexography comprising a base layer and a layer of a photosensitive material fixed on the base layer, of the type in which the product is produced. an image on the photosensitive layer by causing selective radiation curing by irradiation in areas to be raised by the light of a predetermined wavelength, and an arrangement made by this method.
  • a method and an arrangement of this type are already known from French Patent No. 2,834,802.
  • the method according to the invention is characterized in that the image is produced in the form of a set of points which are given a substantially pyramidal shape, which widen in the direction of the base layer. .
  • only the area of the apex of an image point is exposed to the all the light energy necessary for the complete crosslinking of the photosensitive layer in this zone and the zones around the vertex at fractions of this energy, which decrease in the direction of distance from the vertex zone so that the solubility of the material of the photosensitive layer in these areas increases in this direction.
  • the method is characterized in that an image point is produced in the form of a halftone dot formed by a multitude of pixels.
  • the method is characterized in that the insolation light of the photosensitive material layer is a laser beam having a wavelength of between 390 and 410 nm, preferably of order of 405 nm.
  • the method is characterized in that light sources operating in the UV range with a wavelength of 325 to 375 nm are used, these sources being able to be lasers.
  • the method is characterized in that a halftone dot is formed by successively exposing decreasing wavelength area areas to an irradiation energy level corresponding to an appropriate fraction of the wavelength. energy required for the total crosslinking of the photosensitive material.
  • the method is characterized in that a halftone dot is produced by several round trips of a laser beam.
  • the method is characterized in that a halftone dot is produced by different scans implemented by using a plurality of laser beams operating in parallel during the same passage.
  • the method is characterized in that a halftone dot is produced by the use of a support head of a row of a plurality of lasers offset in the direction perpendicular to the scanning , which advances after each scan in the direction perpendicular to the scan by one step corresponding to the width of a different exposure area in the direction of advance.
  • the method is characterized in that the power per laser is between 10 and 300 mW, preferably between 10 and 20 mW.
  • the method is characterized in that the size of the pixels used to scan the surface to be imaged is between 6 to 15 micrometers.
  • the method is characterized in that the number of lasers used is advantageously between 1 and 256.
  • the method is characterized in that the resolution of the embossed image produced is between 1000 dpi and 8000 dpi. According to yet another characteristic of the invention, the method is characterized in that the lines are between 60 lpi and 200 lpi.
  • the method is characterized in that relief images of plates, sleeves and cylinders are used as support.
  • the process is characterized in that photopolymers are used in the liquid or semi-liquid or solid phase.
  • the method is characterized in that the support arrangement is likely to be with or without sole, compressible or not.
  • the method is characterized in that the support is polyester or the like.
  • the method is characterized in that the support is made of metal such as steel or aluminum.
  • the method is characterized in that it comprises a layer of a photosensitive material whose outer face is in relief and formed by image points of pyramidal shape.
  • the method characterized in that an image point is formed by a plurality of pixels.
  • the method is characterized in that the photosensitive layer is fixed on a support.
  • the method is characterized in that the support is in the form of a plate, a sleeve or a cylinder.
  • the method is characterized in that the support is made of polyester or a metal such as steel or aluminum.
  • the method is characterized in that a plate, sleeve or cylinder has a thickness of photosensitive material of between 0.4 mm and 6.35 mm.
  • the method is characterized in that the hardnesses of the plates, sleeve or cylinder are between ShA and 75 ShD.
  • the method is characterized in that the Image resolution is between 1000 dpi and 8000 dpi.
  • the method is characterized in that the lines are between 50 lpi and 200 lpi.
  • the method is characterized in that the lasers are modulated in power.
  • the method is characterized in that the image is produced by multiple scans during the same passage or during successive passages with a laser control by digital files allowing modulate the total energy received at each point of the relief plate to be imaged to control the shoulders of the printing areas, after etching, and to optimize the tonal range and the holding of the details
  • the modulation of the energy at each point of the relief plate to be imaged or the printer shape to be achieved can be achieved by the effect of several physical passages of the lasers as a whole on the surface of it with each time a scan at each point.
  • Said modulation can also be done in a single pass of the assembly of lasers with a recovery at each advance, or revolution in the case of a helical scan on a drum, allowing multiple scans power modulated individually at each point.
  • a passage thus characterizes the advance of the laser head as a whole and a scan the action of the laser (s) at each point insolated.
  • FIG. 1 is a schematic view showing the principle of a relief image on a relief printing plate
  • FIG. 2A schematically illustrates a raster point produced without gradation of the crosslinking around the point and FIG. 2B schematically illustrates a raster dot made according to the invention
  • FIGS. 3A and 3B schematically illustrate two phases of the construction of a halftone dot, in accordance with the invention
  • FIG. 4 is a diagrammatic view of the relief of the raster point whose two phases of construction are shown in FIGS. 3A and 3B;
  • FIG. 5 is a schematic view illustrating the embodiment, according to the invention, of a thin line according to the invention
  • FIG. 6 is a schematic view of a halftone dot of wide diameter and close to another in a shadow zone, according to the invention
  • FIGS. 7 to 9 illustrate strategies for the implementation of three phases of the construction by multiple passes of the insolation light, of a halftone dot according to the invention
  • FIG. 10 is a diagrammatic representation of the digital dot gain offset in the half-tones relative to the theoretical reference line for multi-pass construction applications according to the invention.
  • FIGS. 11 to 13 illustrate three variants of the multi-passage construction of a weft dot according to the invention
  • FIG. 14 is a schematic view illustrating the production of a halftone dot according to the invention, using a head with a plurality of laser beams
  • FIGS. 15A to 15F illustrate six scans and their result, of the method of constructing a halftone dot according to FIG. 14.
  • the invention will be described in its application to a method of performing imaging of a plate or flexographic plate.
  • the invention can be used in other fields such as embossing, typography and gravure-type applications.
  • flexographic plate and sleeve imaging it uses as irradiation light source areas to cross-link laser diodes operating in the violet range, at the boundary between ultraviolet and visible light, with a length of 390 to 410 nm wave and photopolymers adapted and made responsive to this light.
  • An array of laser diodes operating in parallel at wavelengths of 405 nm, arranged to direct parallel beams of specified spacing light on the plate or sleeve and substantially perpendicular to their surface, is preferably used.
  • These diodes have the advantage that they are used massively in data storage systems and offset plate making applications involving certain types of processes known under the terms "Computer to Plate” (CTP).
  • CTP Computer to Plate
  • the invention uses the technology known as "autotypical halftone process", according to which the image is in relief and formed by raster points which consist of a plurality of elementary points called pixels and whose production involves the use of digital technology.
  • the invention therefore relates to a digital imaging method directly on a plate made of a photosensitive material by analogy with the imaging on a negative film or a mask called “ablatable” or a printed format.
  • FIG. 1 illustrates the principle of a relief image according to the invention comprising black areas which have been exposed to light and which are therefore crosslinked and unexposed zones, in white, in which the material of the photosensitive layer has could be removed using for example a solvent.
  • the relief pattern namely the letter "E” is formed by juxtaposed pixels, each in a cell of a grid of rows and columns.
  • a halftone dot covers a certain percentage of the surface and it is the integrating faculty of the observer's eye that makes the latter does not see that the image is formed by distinct points, but sees only a continuous relief zone, provided of course that the resolution is sufficiently high.
  • Resolution means the density of the number of dots reproduced at the ink dot printing, defined by the expression dpi (dots per inch).
  • dpi dots per inch
  • linearization refers to the number of halftone cells per inch. The line is used to print gray levels or to separate colors.
  • weft line by inch lpi (line per inch) or lines per centimeter.
  • lpi line per inch
  • lines per centimeter When one speaks further of a tram of for example 1%, it is a value of surface coverage in percent by halftone dots for a given lineation, for example between 130 or 175 lpi. 175 lpi corresponds to 69 lines per centimeter
  • FIGS. 2A and 2B illustrate in A a dot halftone 1 which has a pyramidal shape and a crown surface 2, that is to say the same contact during printing, which is flat and does not increase substantially thanks to the shoulders 3 stable point, even when they deform under the effect of printing.
  • the pyramidal structure according to the invention of the halftone dots each formed by a multitude of pixels is obtained by a control of the shoulders 3 of the dots and lines by a metering of the light incident in the photosensitive material of the plate to be imaged.
  • the light advantageously formed by a laser beam is coherent and substantially perpendicular to the surface of the plate, the radiation-induced crosslinking is predominantly in the depth according to the swept pattern on the surface of the plate.
  • the shoulders 3 of the high-light points and the positive lines depend exclusively on the diffusion of light in the medium, that is to say the photosensitive material.
  • the invention is based on the fact that the vertices of the points, to be fully crosslinked and able to withstand the subsequent washing, must have received a predetermined amount of energy, while the areas which received less light energy are less crosslinked and are more solubilizable accordingly.
  • the energy required for the crosslinking of the photosensitive material can be dispensed in one exposure, namely a single scanning by laser beam or in several successive passes at the same point or pixel.
  • the fact of distributing the energy over several sequenced scans makes it possible to modulate the dose of light dispensed at each point of the future plate or each pixel, each scanning being determined by digital instructions coming from what is called a ripped, programmed file.
  • the generation of a 1% raster point or of an isolated point of small diameter can be done by scanning a first time as if the distribution of the pixels which form this point corresponded to a halftone dot enlarged to 40% according to Figure 3A. This is the 40% area in light gray around the center in dark gray of 1% later forming the top 2 which is irradiated during this first pass.
  • a scan is performed with a pixel distribution corresponding to a 6% screen dot magnified in accordance with FIG. 3B.
  • the pixels in the 6% circle have received energy from two passes, they are more cross-linked than the pixels between the 6% circle and the circle. 40% and therefore less solubilizable.
  • the creation of the 1% screen dot is then completed by scanning a suitable number of additional times, so that only the 1% circle area is fully crosslinked and therefore completely insoluble.
  • the invention makes it possible to optimize the construction of the points.
  • the fact of sending energy during the first two passes in the vicinity of the weft point to be formed makes it possible to insolubilize the material in this zone in a very controlled manner and thus creates an optimum shoulder which remains after etching by solvent or by thermally, as shown in Figure 4.
  • the halftone dot should have shoulders on making it mechanically unstable. It is easy to understand that by varying the energy input near the point of high light to be imaged, it is possible to control the shoulder and the anchoring thereof. Several passages allow a concentration by concentric circles or in any other desired geometric form.
  • the generation of a positive fine line in relief of 100 ⁇ m (micrometers) for example can similarly be carried out with several passes.
  • the first pass could usefully be done with a pixel distribution corresponding to a line of 200 microns overflowing each side of the desired line of 50 microns.
  • the second passage could usefully be done with a pixel distribution corresponding to a line of 120 microns overflowing each side of the desired line of 10 microns.
  • the other passages will be done with a pixel distribution corresponding to the 100 ⁇ m line as desired.
  • Figure 5 illustrates what has just been described. Symmetrically, the effects of light scattering in shadows can be reduced by manipulating pixel files in reverse with multi-pass imaging. For a screened shadow of 98%, we can make a first passage at 50%, then a passage to 92% and then passages to 98% to reduce the diffusion effects affecting the opening of reserves, as seen on the figure 6.
  • a 200 micrometer stock for example, or could manipulate its numerical size by making two passes with a size of 200 micrometers followed by a passage with a size of 240 micrometers and ending with a passage or the reserve is brought to a size of size of 300 micrometers.
  • FIGS. 7 to 9 illustrate the principle of the digital manipulation of the halftone dots in which the applications which have just been given are given with reference to FIGS. 2 to 6 by way of example.
  • These figures illustrate the correspondence between the halftone dots indicated on the abscissa in% recovery by the point RP, the cell containing the latter and the distribution of the RPX pixels, appearing on the ordinate, created on the plate for each passage.
  • Figure 7 shows that all halftone dots less than 50% theoretical are digitally magnified at the first pass at 50%, which corresponds to the light gray area of Figure 2 and the area shown in Figure 4.
  • FIG. 8 gives the graph shown the manipulation performed during the second pass. The horizontal part of the graph corresponds to the distribution of the pixels in the light gray circle of FIG. 3.
  • FIG. 9 shows the correspondence between the raster points and the pixels for the following passages.
  • FIG. 11 shows the correspondence between the halftone dots and the distribution of the halftone dots.
  • Figures 12 and 13 show two variations of the strategy of construction of the halftone dots, with each time four sweeps.
  • the different scans can also be implemented by using several laser beams operating in parallel, which makes it possible to make only one passage by superimposing the effects of the different lasers in several simultaneous scans.
  • 48 lasers could be separated into four sections of twelve lasers each with the first section doing the work relating to the first one. passage, the second section doing the work relating to the second pass and so on.
  • only 45 out of 48 lasers could be used, leaving three lasers at rest and grouping the lasers into five sections of nine each. This will allow for a fivefold scan.
  • FIG. 14 diagrammatically illustrates the pyramidal configuration of a dot marked 1 on a base layer 5.
  • the figure shows, from the base to the top, four zones e to h concentric (from the outside to the inside) of decreasing width, which can be achieved by four exposures to successive irradiation light.
  • the figure also shows the zone 7e to 7h which is each time irradiated. At each exposure, the corresponding area was irradiated with a quarter of the energy.
  • the size of the irradiated area of the point was 80 micrometers, at the second exposure of 60 micrometers, at the third and fourth exposures of 40 and 20 microns, respectively.
  • the thick and inclined lines represent the shoulders 3 of the point after completion.
  • the back of the plate was made by exposure from below to harden the bottom of the plate material to provide point support.
  • the different sizes of the dots can be made according to a suitable image grid processing software known as the Raster Image Processor Software (RIP).
  • FIGS. 15A to 15F schematically illustrate, by way of simplified example, the embodiment of the raster point according to FIG. 14, involving the use of a mobile head 8 carrying eight beams lasers noted 6, the first laser beam being at the bottom, the eighth at the top of the inclined row of lasers.
  • the scanning direction is indicated by the arrow Fl.
  • the laser head advances after each pass a step of 20 micrometers in the direction of the arrow F2.
  • Figures 15A to 15F illustrate the different positions of the head and, by hatching, the exposure to laser light performed at each of the six scans. It is thus found that the lines L4 and L5 (shown in FIG. 14) received four times of the laser light in the zone denoted 7H in FIG.
  • the energy distribution performed with these four scans and during a single pass allows, after etching, to generate a controlled shoulder of the raster dot.
  • the description of the invention which has just been given has only been given by way of example and can be modified in many ways provided that the essential characteristics of the invention are respected.
  • This one generally proposes the creation of relief printing forms, for flexography, typography and any other similar application.
  • the invention thus also covers embossing applications in relief and heliogravure type applications. These reliefs can be made on supports in the form of plate, sleeve and cylinders.
  • the invention covers the use of photopolymers implemented in liquid or semi-liquid or solid phase.
  • the plates may be with or without a sole, compressible or not, on a polyester support, or the like, on a steel or aluminum support.
  • the lasers are preferably diodes in semiconductor technology.
  • Lasers are modulated between a minimum light emission power, where appropriate zero, and a nominal maximum power. Successive passes can be at the same or different power levels to optimize the results.
  • the plates may have a thickness of between about 0.4 mm and 6.35 mm.
  • the hardnesses of the formed sleeves or rolls are typically from about ShA to 75 ShD.
  • the plates may be monolayer or multilayer.
  • the energy densities necessary for crosslinking the photosensitive materials are typically between 40 and 1000 mJ / cm 2 . It is preferably between 50 and 150 mJ / cm 2 .
  • the lasers are preferably diodes operating at a wavelength of 405 nm or with wavelengths between 390 and 410 nm.
  • This method can also be applied to lasers operating in the UV range with wavelengths of approximately 325 to 375 nm.
  • the laser power output can vary between 10 and 300 mW, preferably between 10 and 200 mW.
  • the power applied to each laser module may be different from the others.
  • the size of the elementary pixels used to scan the surface of the embossed form is typically 6 to 15 microns.
  • the number of lasers used is arbitrary and can vary between 1 and 256 or even more depending on their power or the energy required to crosslink the material.
  • the resolution of the image is between approximately 1,000 dpi and 8,000 dpi.
  • the lines involved in the applications range from about 50 lpi to 200 lpi.
  • the number of sweeps or successive passes is between 2 and 16 typically, 3 to 4 preferably, and the number of different ripped files used during these scans is typically 2 to 5, preferably 3 or 4.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Electromagnetism (AREA)
  • Manufacture Or Reproduction Of Printing Formes (AREA)
  • Photosensitive Polymer And Photoresist Processing (AREA)

Abstract

The invention relates to a method of producing a relief image arrangement, usable especially in the fields of flexography, embossing and heliogravure, and comprising a base layer and a layer of photosensitive material fixed on the base layer. The method is of the type according to which an image is produced on the photosensitive layer by causing selective curing by irradiating the zones that are to be in relief with light of a predetermined wavelength. The method is characterized in that the image is produced in the form of a set of points to which a substantially pyramidal shape is given, widening out in the direction of the base layer (5). The invention is usable for producing relief images, in the field of flexography.

Description

« Procédé de réalisation d'un agencement à image en relief utilisable notamment dans le domaine de la flexographie et agencement réalisé selon ce procédé ». "Process for producing a relief image arrangement that can be used especially in the field of flexography and an arrangement made according to this method".
L'invention concerne un procédé de réalisation d'un agencement à image en relief utilisable notamment dans le domaine de la flexographie comportant une couche de base et une couche d'un matériau photosensible fixée sur la couche de base, du type selon lequel on produit une image sur la couche photosensible en provoquant une réticulation sélective par insolation dans des zones devant être en relief par la lumière d'une longueur d'onde prédéterminée, et un agencement réalisé selon ce procédé . Un procédé et un agencement de ce type sont déjà connus par le brevet français n° 2 834 802. Or, il s'est avéré que la technologie décrite dans ce brevet présente l'inconvénient que les parties en relief formées par des points de tramé et des lignes positives ont des configurations d'épaulement qui ont pour conséquence que des points de faible diamètre et espacés ou des lignes positives étroites sont fragiles à la gravure des clichés et instables en se déformant sous l'effet de la pression d'impression provoquant un manque d'étendue tonale dans les hautes lumières ou un manque de détail de façon plus générale. En outre, des points obtus, plus larges et plus rapprochés dans les ombres constituent des réserves bouchées, ce qui provoque un engraissement excessif et des ombres limitées en étendue tonale également. L'invention a pour but de pallier cet inconvénient.The invention relates to a method for producing a relief image arrangement that can be used in particular in the field of flexography comprising a base layer and a layer of a photosensitive material fixed on the base layer, of the type in which the product is produced. an image on the photosensitive layer by causing selective radiation curing by irradiation in areas to be raised by the light of a predetermined wavelength, and an arrangement made by this method. A method and an arrangement of this type are already known from French Patent No. 2,834,802. However, it has been found that the technology described in this patent has the disadvantage that the raised parts formed by dot halftone and positive lines have shoulder configurations which result in small, spaced-apart dots or narrow positive lines being brittle at the plate etch and unstable by deforming under the effect of the causing printing pressure. a lack of tonal range in highlights or a lack of detail more generally. In addition, obtuse, wider and closer shadows are clogged resistances, resulting in excessive fattening and limited shadows in tonal range as well. The invention aims to overcome this disadvantage.
Pour atteindre ce but, le procédé selon l'invention est caractérisé en ce que l'on réalise l'image sous forme d'un ensemble de points auxquels on donne une forme sensiblement pyramidale, qui s'élargissent en direction de la couche de base.To achieve this goal, the method according to the invention is characterized in that the image is produced in the form of a set of points which are given a substantially pyramidal shape, which widen in the direction of the base layer. .
Selon une caractéristique de l'invention, on expose seulement la zone du sommet d'un point d'image à la totalité de l'énergie lumineuse nécessaire pour la réticulation complète de la couche photosensible dans cette zone et les zones autour du sommet a des fractions de cette énergie, qui diminuent dans la direction d ' éloignement de la zone de sommet pour que la solubilité du matériau de la couche photosensible dans ces zones augmente dans cette direction.According to one characteristic of the invention, only the area of the apex of an image point is exposed to the all the light energy necessary for the complete crosslinking of the photosensitive layer in this zone and the zones around the vertex at fractions of this energy, which decrease in the direction of distance from the vertex zone so that the solubility of the material of the photosensitive layer in these areas increases in this direction.
Selon une caractéristique de l'invention, le procédé est caractérisé en ce qu'un point d'image est réalisé sous forme d'un point de tramé formé par une multitude de pixels.According to one characteristic of the invention, the method is characterized in that an image point is produced in the form of a halftone dot formed by a multitude of pixels.
Selon une autre caractéristique de l'invention, le procédé est caractérisé en ce que la lumière d'insolation de la couche de matériau photosensible est un faisceau laser d'une longueur d'onde comprise entre 390 et 410 nm, de préférence de l'ordre de 405 nm.According to another characteristic of the invention, the method is characterized in that the insolation light of the photosensitive material layer is a laser beam having a wavelength of between 390 and 410 nm, preferably of order of 405 nm.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que l'on utilise des sources lumineuses fonctionnant dans le domaine UV avec une longueur d'ondes de 325 à 375 nm, ces sources pouvant être des lasers .According to yet another characteristic of the invention, the method is characterized in that light sources operating in the UV range with a wavelength of 325 to 375 nm are used, these sources being able to be lasers.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce qu'un point de tramé est formé par exposition successive de zones du point de tailles décroissantes à un niveau d'énergie d'irradiation correspondant a une fraction appropriée de l'énergie nécessaire pour la réticulation totale du matériau photosensible .According to yet another characteristic of the invention, the method is characterized in that a halftone dot is formed by successively exposing decreasing wavelength area areas to an irradiation energy level corresponding to an appropriate fraction of the wavelength. energy required for the total crosslinking of the photosensitive material.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce qu'un point de tramé est réalisé par plusieurs passages aller-retour d'un faisceau laser.According to yet another characteristic of the invention, the method is characterized in that a halftone dot is produced by several round trips of a laser beam.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce qu'un point de tramé est réalisé par différents balayages mis en œuvre en utilisant plusieurs faisceaux laser fonctionnant en parallèle lors d'un même passage. Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce qu'un point de tramé est réalisé par l'utilisation d'une tête support d'une rangée d'une pluralité de lasers décalés dans la direction perpendiculaire au balayage, qui avance après chaque balayage dans la direction perpendiculaire au balayage d ' un pas correspondant à la largeur d ' une zone d'exposition différente dans la direction d'avance.According to yet another characteristic of the invention, the method is characterized in that a halftone dot is produced by different scans implemented by using a plurality of laser beams operating in parallel during the same passage. According to yet another characteristic of the invention, the method is characterized in that a halftone dot is produced by the use of a support head of a row of a plurality of lasers offset in the direction perpendicular to the scanning , which advances after each scan in the direction perpendicular to the scan by one step corresponding to the width of a different exposure area in the direction of advance.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que la puissance par laser est comprise entre 10 et 300 mW, de préférence entre 10 et 20 mW.According to yet another characteristic of the invention, the method is characterized in that the power per laser is between 10 and 300 mW, preferably between 10 and 20 mW.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que la taille des pixels utilisés pour balayer la surface à imager est comprise entre 6 à 15 micromètres.According to yet another characteristic of the invention, the method is characterized in that the size of the pixels used to scan the surface to be imaged is between 6 to 15 micrometers.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que le nombre de lasers utilisés est avantageusement compris entre 1 et 256.According to yet another characteristic of the invention, the method is characterized in that the number of lasers used is advantageously between 1 and 256.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que la résolution de 1 ' image en relief réalisée est comprise entre 1000 dpi et 8000 dpi. Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que les linéatures sont comprises entre 60 lpi à 200 lpi .According to yet another characteristic of the invention, the method is characterized in that the resolution of the embossed image produced is between 1000 dpi and 8000 dpi. According to yet another characteristic of the invention, the method is characterized in that the lines are between 60 lpi and 200 lpi.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce qu'on utilise comme support des images en relief des plaques, des manchons et des cylindres.According to yet another characteristic of the invention, the method is characterized in that relief images of plates, sleeves and cylinders are used as support.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce qu'on utilise des photopolymères en phase liquide ou semi- liquide ou solide.According to yet another characteristic of the invention, the process is characterized in that photopolymers are used in the liquid or semi-liquid or solid phase.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que l'agencement de support est susceptible d'être avec ou sans semelle, compressible ou non.According to yet another characteristic of the invention, the method is characterized in that the support arrangement is likely to be with or without sole, compressible or not.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que le support est du polyester ou analogue .According to yet another characteristic of the invention, the method is characterized in that the support is polyester or the like.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que le support est en métal tel que de l'acier ou aluminium.According to yet another characteristic of the invention, the method is characterized in that the support is made of metal such as steel or aluminum.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce qu'il comporte une couche d'un matériau photosensible dont la face extérieure est en relief et formée par des points d ' image de forme pyramidale .According to yet another characteristic of the invention, the method is characterized in that it comprises a layer of a photosensitive material whose outer face is in relief and formed by image points of pyramidal shape.
Selon encore une autre caractéristique de l'invention, le procédé caractérisé en ce qu'un point d'image est formé par une pluralité de pixels.According to yet another characteristic of the invention, the method characterized in that an image point is formed by a plurality of pixels.
Selon encore une autre caractéristique de 1 ' invention, le procédé est caractérisé en ce que la couche photosensible est fixée sur un support . Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que le support est en forme d'une plaque, d'un manchon ou d'un cylindre.According to yet another characteristic of the invention, the method is characterized in that the photosensitive layer is fixed on a support. According to yet another characteristic of the invention, the method is characterized in that the support is in the form of a plate, a sleeve or a cylinder.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que le support est en polyester ou en un métal tel que de l'acier ou de l'aluminium.According to yet another characteristic of the invention, the method is characterized in that the support is made of polyester or a metal such as steel or aluminum.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce qu'une plaque, manchon ou cylindre a une épaisseur de matériau photosensible comprise entre 0,4 mm et 6,35 mm.According to yet another characteristic of the invention, the method is characterized in that a plate, sleeve or cylinder has a thickness of photosensitive material of between 0.4 mm and 6.35 mm.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que les duretés des plaques, manchon ou cylindre sont comprises entre 25 ShA et 75 ShD.According to yet another characteristic of the invention, the method is characterized in that the hardnesses of the plates, sleeve or cylinder are between ShA and 75 ShD.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que la résolution de l'image est comprise entre 1000 dpi et 8000 dpi .According to yet another characteristic of the invention, the method is characterized in that the Image resolution is between 1000 dpi and 8000 dpi.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que les linéatures sont comprises entre 50 lpi à 200 lpi .According to yet another characteristic of the invention, the method is characterized in that the lines are between 50 lpi and 200 lpi.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que les lasers sont modulés en puissance .According to yet another characteristic of the invention, the method is characterized in that the lasers are modulated in power.
Selon encore une autre caractéristique de l'invention, le procédé est caractérisé en ce que l'on réalise l'image par des balayages multiples lors d'un même passage ou lors de passages successifs avec un pilotage des lasers par des fichiers numériques permettant de moduler l ' énergie totale reçue en chaque point de la plaque en relief à imager pour contrôler les épaulements des zones imprimantes, après gravure, et pour optimiser l'étendue tonale et la tenue des détailsAccording to yet another characteristic of the invention, the method is characterized in that the image is produced by multiple scans during the same passage or during successive passages with a laser control by digital files allowing modulate the total energy received at each point of the relief plate to be imaged to control the shoulders of the printing areas, after etching, and to optimize the tonal range and the holding of the details
II convient d'insister sur le fait que la modulation de l'énergie en chaque point de la plaque en relief à imager ou de la forme imprimante à réaliser peut se faire par l'effet de plusieurs passages physiques des lasers dans leur ensemble sur la surface de celle-ci avec à chaque fois un balayage au niveau de chaque point.It should be emphasized that the modulation of the energy at each point of the relief plate to be imaged or the printer shape to be achieved can be achieved by the effect of several physical passages of the lasers as a whole on the surface of it with each time a scan at each point.
La dite modulation peut se faire également en un seul passage de l'assemblage des lasers avec un recouvrement à chaque avance, ou révolution dans le cas d'un balayage hélicoïdal sur un tambour, permettant des balayages multiples modulés en puissance individuellement en chaque point .Said modulation can also be done in a single pass of the assembly of lasers with a recovery at each advance, or revolution in the case of a helical scan on a drum, allowing multiple scans power modulated individually at each point.
Un passage caractérise donc l'avance de la tête laser dans son ensemble et un balayage l'action du ou des laser (s) au niveau de chaque point insolë.A passage thus characterizes the advance of the laser head as a whole and a scan the action of the laser (s) at each point insolated.
L'invention sera mieux comprise, et d'autres buts, caractéristiques, détails et avantages de celle-ci apparaîtront plus clairement au cours de la description explicative qui va suivre faite en référence aux dessins schématiques annexés donnés uniquement à titre d'exemple illustrant un mode de réalisation de l'invention et dans lesquels :The invention will be better understood, and other objects, features, details and advantages thereof will appear more clearly in the following explanatory description made with reference to the drawings. attached diagrams given solely by way of example illustrating an embodiment of the invention and in which:
- la figure 1 est une vue schématique montrant le principe d'une image en relief sur une plaque d'impression en relief;FIG. 1 is a schematic view showing the principle of a relief image on a relief printing plate;
- la figure 2A illustre schëmatiquement un point de trame réalisé sans gradation de la réticulation autour du point et la figure 2B illustre schématiquement un point de tramé réalisé selon l'invention;FIG. 2A schematically illustrates a raster point produced without gradation of the crosslinking around the point and FIG. 2B schematically illustrates a raster dot made according to the invention;
- les figures 3A et 3B illustrent schématiquement deux phases de la construction d'un point de tramé, conformément à 1 ' invention ;FIGS. 3A and 3B schematically illustrate two phases of the construction of a halftone dot, in accordance with the invention;
- la figure 4 est une vue schématique du relief du point de tramé dont deux phases de construction sont représentées aux figures 3A et 3B ;FIG. 4 is a diagrammatic view of the relief of the raster point whose two phases of construction are shown in FIGS. 3A and 3B;
- la figure 5 est une vue schématique illustrant la réalisation, selon l'invention, d'une ligne fine selon 1 ' invention ; - la figure 6 est une vue schématique d'un point de tramé de diamètre large et proche d'un autre dans une zone d'ombre, conformément à l'invention ;FIG. 5 is a schematic view illustrating the embodiment, according to the invention, of a thin line according to the invention; FIG. 6 is a schematic view of a halftone dot of wide diameter and close to another in a shadow zone, according to the invention;
- les figures 7 à 9 illustrent des stratégies de la mise en œuvre de trois phases de la construction par des passages multiples de la lumière d'insolation, d'un point de tramé selon l'invention ;FIGS. 7 to 9 illustrate strategies for the implementation of three phases of the construction by multiple passes of the insolation light, of a halftone dot according to the invention;
- la figure 10 est une représentation schématique du décalage de l'engraissement numérique du point dans les demi-teintes par rapport à la ligne de référence théorique lors des applications de la construction à passages multiples selon l'invention ;FIG. 10 is a diagrammatic representation of the digital dot gain offset in the half-tones relative to the theoretical reference line for multi-pass construction applications according to the invention;
- les figures 11 à 13 illustrent trois variantes de la construction à passages multiples, d'un point de trame selon l'invention ; - la figure 14 est une vue schématique illustrant la réalisation d'un point de tramé selon l'invention, à l'aide d'une tête à plusieurs faisceaux laser ; et - les figures 15A à 15F illustrent six balayages et leur résultat, du procédé de construction d'un point de tramé selon la figure 14.FIGS. 11 to 13 illustrate three variants of the multi-passage construction of a weft dot according to the invention; FIG. 14 is a schematic view illustrating the production of a halftone dot according to the invention, using a head with a plurality of laser beams; and FIGS. 15A to 15F illustrate six scans and their result, of the method of constructing a halftone dot according to FIG. 14.
L'invention sera décrite dans son application à un procédé de réalisation d'imagerie d'une plaque ou cliché de flexographie . Bien entendu, l'invention peut être utilisée dans d'autres domaines tels que le gaufrage en relief, de typographie et des applications de type héliogravure . Dans son application à l'imagerie de plaque de flexographie et de manchon on utilise comme source lumineuse d'insolation des zones à réticuler des diodes lasers fonctionnant dans le domaine violet, à la frontière entre la lumière ultraviolette et visible, d'une longueur d'onde de 390 à 410 nm et des photopolymères adaptés et rendus sensibles à cette lumière. On utilise de préférence un ensemble de diodes laser fonctionnant en parallèle à des longueurs d'onde de 405 nm, disposées de façon à diriger des faisceaux parallèles de lumière d'écartement spécifié sur la plaque ou le manchon et sensiblement perpendiculairement à leur surface. Ces diodes présentent l'avantage qu'elles sont utilisées massivement dans des systèmes de stockage de données et d'applications de réalisation de plaques offset impliquant certains types de procédés connus sous les termes "Computer to Plate" (CTP) .The invention will be described in its application to a method of performing imaging of a plate or flexographic plate. Of course, the invention can be used in other fields such as embossing, typography and gravure-type applications. In its application to flexographic plate and sleeve imaging, it uses as irradiation light source areas to cross-link laser diodes operating in the violet range, at the boundary between ultraviolet and visible light, with a length of 390 to 410 nm wave and photopolymers adapted and made responsive to this light. An array of laser diodes operating in parallel at wavelengths of 405 nm, arranged to direct parallel beams of specified spacing light on the plate or sleeve and substantially perpendicular to their surface, is preferably used. These diodes have the advantage that they are used massively in data storage systems and offset plate making applications involving certain types of processes known under the terms "Computer to Plate" (CTP).
L'invention utilise la technologie connue sous les termes "autotypical halftone process", selon laquelle 1 ' image est en relief et formée par des points de tramé qui sont constitués d'une pluralité de points élémentaires appelés pixels et dont la réalisation implique l'emploi de la technologie numérique. L'invention concerne donc un procédé d'imagerie numérique directement sur une plaque en un matériau photosensible par analogie avec l'imagerie sur un film négatif ou un masque dit "ablatable" ou un format imprimé. La figure 1 illustre le principe d'une image en relief selon 1 ' invention comportant des zones noires qui ont été exposées à la lumière et qui sont donc réticulées et des zones non exposées, en blanc, dans lesquelles la matière de la couche photosensible a pu être enlevée a l'aide par exemple d'un solvant. On constate que le motif en relief, à savoir la lettre "E" est formée par des pixels juxtaposés, chacun dans une cellule d'une grille de lignes et de colonnes. De façon générale, dans une image en relief selon l'invention, un point de tramé recouvre un certain pourcentage de la surface et c ' est la faculté d'intégration de l'œil de l'observateur qui fait que celui-ci ne s'aperçoit pas que l'image est formée par des points distincts, mais ne voit qu'une zone en relief continue, bien entendu à condition que la résolution soit suffisamment élevée. Sous résolution, on entend la densité du nombre des points reproduits à 1 ' impression par point encré, définie par l'expression dpi (dots per inch, c'est-à-dire point par inch) . Sous le terme "linéature" on entend le nombre de cellules de demi- teinte par inch. La linëature permet d'imprimer les niveaux de gris ou de séparer les couleurs. Elle est aussi appelée trame : ligne par inch lpi (line per inch) ou lignes par centimètres. Lorsqu'on parle plus loin d'un tram de par exemple 1%, il s'agit d'une valeur de recouvrement de surface en pourcent par des points de tramé pour une linéature donnée, par exemple entre 130 ou 175 lpi. 175 lpi correspond à 69 lignes par centimètreThe invention uses the technology known as "autotypical halftone process", according to which the image is in relief and formed by raster points which consist of a plurality of elementary points called pixels and whose production involves the use of digital technology. The invention therefore relates to a digital imaging method directly on a plate made of a photosensitive material by analogy with the imaging on a negative film or a mask called "ablatable" or a printed format. FIG. 1 illustrates the principle of a relief image according to the invention comprising black areas which have been exposed to light and which are therefore crosslinked and unexposed zones, in white, in which the material of the photosensitive layer has could be removed using for example a solvent. It is found that the relief pattern, namely the letter "E" is formed by juxtaposed pixels, each in a cell of a grid of rows and columns. Generally speaking, in a relief image according to the invention, a halftone dot covers a certain percentage of the surface and it is the integrating faculty of the observer's eye that makes the latter does not see that the image is formed by distinct points, but sees only a continuous relief zone, provided of course that the resolution is sufficiently high. Resolution means the density of the number of dots reproduced at the ink dot printing, defined by the expression dpi (dots per inch). The term "linearization" refers to the number of halftone cells per inch. The line is used to print gray levels or to separate colors. It is also called weft: line by inch lpi (line per inch) or lines per centimeter. When one speaks further of a tram of for example 1%, it is a value of surface coverage in percent by halftone dots for a given lineation, for example between 130 or 175 lpi. 175 lpi corresponds to 69 lines per centimeter
L'invention a pour but la réalisation des points d'image, c'est-à-dire de tramé, (en relief) de façon qu'ils aient une forme stable se déformant peu sous l'effet d'impression notamment lorsqu'il s'agit des points de hautes lumières ou provoquant des réserves bouchées, un engraissement excessif et des ombres limitées en étendue tonale. Les figures 2A et 2B illustrent en A un point de tramé 1 qui présente une forme pyramidale et une surface de sommet 2, c'est-à-dire de même contact lors de l'impression, qui est plane et qui n'augmente pas essentiellement grâce aux épaulements 3 stables du point, même lorsque ceux-ci se déforment sous l'effet de l'impression. La structure pyramidale selon l'invention des points de tramé chacun formé par une multitude de pixels est obtenue par un contrôle des épaulements 3 des points et des lignes grâce à un dosage de la lumière incidente dans la matière photosensible de la plaque à imager. Comme la lumière avantageusement formée par un faisceau laser est cohérente et sensiblement perpendiculaire à la surface de la plaque, la réticulation induite par la radiation se fait de façon dominante dans la profondeur selon le motif balayé en surface de la plaque. Les conséquences sont que les épaulements 3 des points de haute lumière et des lignes positives dépendent exclusivement de la diffusion de la lumière dans le milieu, c'est-à-dire le matériau photosensible.The aim of the invention is to produce image points, ie halftone, in relief so that they have a stable shape that deforms little under the printing effect, especially when these are points of highlights or causing clogged reserves, excessive fattening and limited shadows in tonal range. FIGS. 2A and 2B illustrate in A a dot halftone 1 which has a pyramidal shape and a crown surface 2, that is to say the same contact during printing, which is flat and does not increase substantially thanks to the shoulders 3 stable point, even when they deform under the effect of printing. The pyramidal structure according to the invention of the halftone dots each formed by a multitude of pixels is obtained by a control of the shoulders 3 of the dots and lines by a metering of the light incident in the photosensitive material of the plate to be imaged. As the light advantageously formed by a laser beam is coherent and substantially perpendicular to the surface of the plate, the radiation-induced crosslinking is predominantly in the depth according to the swept pattern on the surface of the plate. The consequences are that the shoulders 3 of the high-light points and the positive lines depend exclusively on the diffusion of light in the medium, that is to say the photosensitive material.
L'invention est fondée sur le fait que les sommets des points, pour être totalement réticulés et pouvant résister au lavage ultérieur, doivent avoir reçu une quantité d'énergie prédéterminée, tandis que les zones qui ont reçu moins d'énergie de lumière sont moins réticulées et sont plus solubilisable en conséquence. L'énergie nécessaire pour la réticulation de la matière photosensible peut être dispensée en une exposition, à savoir un seul balayage par faisceau laser ou en plusieurs passages successifs au même point ou pixel . Le fait de répartir l'énergie sur plusieurs balayages séquences permet de moduler la dose de lumière dispensée en chaque point de la future plaque ou chaque Pixel, chaque balayage étant déterminé par des instructions numériques venant de ce qu'on appelle un fichier rippé, programmé de façon à obtenir les effets demandés, à savoir le contrôle des épaulements des points en relief et des zones imprimantes en général après gravure. Ainsi, la génération d'un point de tramé de 1 % ou d'un point isolé de diamètre faible pourra se faire en balayant une première fois comme si la répartition des pixels qui forment ce point correspondait à un point de tramé grossi à 40 %, conformément à la figure 3A. C'est la zone 40 % en gris clair autour du centre en gris foncé de 1 % formant ultérieurement le sommet 2 qui est irradiée au cours de ce premier passage. Lors d'un second passage on balaye avec une répartition de pixel correspondant à un point de tramé grossi à 6 %, conformément à la figure 3B. Etant donné que, dans la matière, c'est-à-dire les pixels se trouvant dans le cercle de 6 % ont reçu l'énergie de deux passages, ils sont plus réticulés que les pixels entre le cercle de 6 % et le cercle de 40 % et donc moins solubilisable. La création du point de trame de 1 % est ensuite complétée en balayant un nombre de fois supplémentaires appropriées, de façon que seulement la zone correspondant au cercle de 1 % soit entièrement réticulée et donc entièrement insoluble.The invention is based on the fact that the vertices of the points, to be fully crosslinked and able to withstand the subsequent washing, must have received a predetermined amount of energy, while the areas which received less light energy are less crosslinked and are more solubilizable accordingly. The energy required for the crosslinking of the photosensitive material can be dispensed in one exposure, namely a single scanning by laser beam or in several successive passes at the same point or pixel. The fact of distributing the energy over several sequenced scans makes it possible to modulate the dose of light dispensed at each point of the future plate or each pixel, each scanning being determined by digital instructions coming from what is called a ripped, programmed file. so as to obtain the effects requested, namely the control of the shoulders of the raised points and the printing areas in general after etching. Thus, the generation of a 1% raster point or of an isolated point of small diameter can be done by scanning a first time as if the distribution of the pixels which form this point corresponded to a halftone dot enlarged to 40% according to Figure 3A. This is the 40% area in light gray around the center in dark gray of 1% later forming the top 2 which is irradiated during this first pass. In a second pass, a scan is performed with a pixel distribution corresponding to a 6% screen dot magnified in accordance with FIG. 3B. Since in the material, i.e., the pixels in the 6% circle have received energy from two passes, they are more cross-linked than the pixels between the 6% circle and the circle. 40% and therefore less solubilizable. The creation of the 1% screen dot is then completed by scanning a suitable number of additional times, so that only the 1% circle area is fully crosslinked and therefore completely insoluble.
En modulant les énergies fournies par le laser à chaque passage, on peut appliquer des valeurs d'énergie différentes .By modulating the energies provided by the laser at each pass, different energy values can be applied.
L'invention permet d'optimiser la construction des points. Le fait d'envoyer de l'énergie lors des deux premiers passages dans le voisinage du point de trame à former permet d' insolubiliser la matière dans cette zone de manière très contrôlée et crée ainsi un épaulement optimal qui reste après gravure par solvant ou par voie thermique, comme l'illustre la figure 4. Or, en l'absence de la manipulation de la taille des points de tramé lors de deux ou plusieurs balayages, tels qu'exposés ci- dessus, le point de tramé aurait des épaulements le rendant instable mécaniquement . On comprend aisément qu'en variant l'apport d'énergie au voisinage du point de haute lumière à imager, on peut contrôler l'ëpaulement et l'ancrage de celui-ci. Plusieurs passages permettent un dosage par cercles concentriques ou sous tout autre forme géométrique souhaitée.The invention makes it possible to optimize the construction of the points. The fact of sending energy during the first two passes in the vicinity of the weft point to be formed makes it possible to insolubilize the material in this zone in a very controlled manner and thus creates an optimum shoulder which remains after etching by solvent or by thermally, as shown in Figure 4. However, in the absence of the manipulation of the size of the halftone dots during two or more scans, as explained above, the halftone dot should have shoulders on making it mechanically unstable. It is easy to understand that by varying the energy input near the point of high light to be imaged, it is possible to control the shoulder and the anchoring thereof. Several passages allow a concentration by concentric circles or in any other desired geometric form.
La génération d'une ligne fine positive en relief de 100 μm (micromètres) par exemple peut de façon similaire être réalisée avec plusieurs passages. Le premier passage pourrait utilement se faire avec une répartition de pixels correspondant à une ligne de 200 μm débordant de chaque côté de la ligne voulue de 50 μm. Le deuxième passage pourrait utilement se faire avec une répartition de pixels correspondant à une ligne de 120 μm débordant de chaque côté de la ligne voulue de 10 μm. Les autres passages se feront avec une répartition de pixels correspondant à la ligne de 100 μm telle que souhaitée. La figure 5 illustre ce qui vient d'être décrit. De manière symétrique, on peut réduire les effets de diffusion de lumière dans les ombres en manipulant en sens inverse les fichiers de pixels avec une imagerie à plusieurs passages. Pour une ombre tramée de 98 %, on pourra faire un premier passage à 50 %, puis un passage à 92 % et ensuite des passages à 98 % pour diminuer les effets de diffusion affectant l'ouverture des réserves, comme on le voit sur la figure 6.The generation of a positive fine line in relief of 100 μm (micrometers) for example can similarly be carried out with several passes. The first pass could usefully be done with a pixel distribution corresponding to a line of 200 microns overflowing each side of the desired line of 50 microns. The second passage could usefully be done with a pixel distribution corresponding to a line of 120 microns overflowing each side of the desired line of 10 microns. The other passages will be done with a pixel distribution corresponding to the 100 μm line as desired. Figure 5 illustrates what has just been described. Symmetrically, the effects of light scattering in shadows can be reduced by manipulating pixel files in reverse with multi-pass imaging. For a screened shadow of 98%, we can make a first passage at 50%, then a passage to 92% and then passages to 98% to reduce the diffusion effects affecting the opening of reserves, as seen on the figure 6.
De même pour une réserve de 200 micromètres par exemple, ou pourrait manipuler sa taille numérique en effectuant deux passages avec une taille de 200 micromètres suivi d'un passage avec une taille de 240 micrimètres et finissant avec un passage ou la réserve est portée à une taille de 300 micromètres.Likewise for a 200 micrometer stock, for example, or could manipulate its numerical size by making two passes with a size of 200 micrometers followed by a passage with a size of 240 micrometers and ending with a passage or the reserve is brought to a size of size of 300 micrometers.
Les figures 7 à 9 illustrent le principe de la manipulation numérique des points de tramé dans lesquels s'inscrivent les applications qui viennent d'être données en se référant aux figures 2 à 6 à titre d'exemple. Ces figures illustrent la correspondance entre les points de tramé indiqués sur l'abscisse en % de recouvrement par le point RP, de la cellule contenant celui-ci et la répartition des pixels RPX, figurant sur l'ordonnée, créés sur la plaque pour chaque passage. La figure 7 montre que tous les points de tramé de dimension inférieure à 50 % théoriques sont grossis numériquement au premier passage à 50 %, ce qui correspond à la zone en gris clair de la figure 2 et la zone indiquée à la figure 4. De façon similaire, la figure 8 donne par le graphe représenté la manipulation effectuée lors du deuxième passage. La partie horizontale du graphe correspond à la répartition des pixels se trouvant dans le cercle en gris clair de la figure 3. La figure 9 présente la correspondance entre les points de tramé et les pixels pour les passages suivants .FIGS. 7 to 9 illustrate the principle of the digital manipulation of the halftone dots in which the applications which have just been given are given with reference to FIGS. 2 to 6 by way of example. These figures illustrate the correspondence between the halftone dots indicated on the abscissa in% recovery by the point RP, the cell containing the latter and the distribution of the RPX pixels, appearing on the ordinate, created on the plate for each passage. Figure 7 shows that all halftone dots less than 50% theoretical are digitally magnified at the first pass at 50%, which corresponds to the light gray area of Figure 2 and the area shown in Figure 4. Similarly, FIG. 8 gives the graph shown the manipulation performed during the second pass. The horizontal part of the graph corresponds to the distribution of the pixels in the light gray circle of FIG. 3. FIG. 9 shows the correspondence between the raster points and the pixels for the following passages.
Il est à noter qu'on peut superposer un décalage de la ligne de référence théorique pour modifier l'engraissement des points de trame dans les demi-teintes notamment, comme l'illustre à titre d'exemple la figure 10.It should be noted that it is possible to superimpose an offset of the theoretical reference line to modify the fattening of the screen points in the half-tones in particular, as illustrated by way of example in FIG.
Selon l'invention, on peut également combiner la manipulation des points de tramé en hautes lumières avec la manipulation correspondante des points d'ombre, comme on le voit sur la figure 11 et qui montre la correspondance entre les points de tramé et la répartition des pixels pour quatre balayages successifs a, b, c, d. Les figures 12 et 13 montrent deux variations de la stratégie de construction des points de tramé, avec à chaque fois quatre balayages.According to the invention, it is also possible to combine the manipulation of the halftone halftone dots with the corresponding manipulation of the shadow dots, as can be seen in FIG. 11, which shows the correspondence between the halftone dots and the distribution of the halftone dots. pixels for four successive scans a, b, c, d. Figures 12 and 13 show two variations of the strategy of construction of the halftone dots, with each time four sweeps.
Ci-avant, la réalisation des points de tramé a été décrite par accomplissement de plusieurs passages et donc balayages successifs en surface par exemple par des allers-retours d'un faisceau laser dans son ensemble. Conformément à l'invention, les différents balayages peuvent également être mis en œuvre en utilisant plusieurs faisceaux lasers fonctionnant en parallèle, ce qui permet de ne faire qu'un seul passage en superposant les effets des différents lasers en plusieurs balayages simultanés. Ainsi, 48 lasers pourraient être séparés en quatre sections de douze lasers chacune avec la première section qui effectue le travail relatif au premier passage, la deuxième section qui effectue le travail relatif au deuxième passage et ainsi de suite. En variante, on ne pourrait utiliser que 45 lasers sur 48 en laissant trois lasers au repos et regrouper les lasers en cinq sections de neuf chacune. Ceci permettra d'effectuer un balayage quintuple. Selon une autre variante, on pourrait répartir les lasers en huit sections de six lasers et effectuer huit balayages à une vitesse huit fois plus grande. Ce deuxième mode de mise en œuvre de l'invention sera décrit plus en détail ci-après en se référant à la figure 14. La figure 14 illustre schématiquement la configuration pyramidale d'un point de tramé noté 1 sur une couche de base 5. La figure montre, à partir de la base vers le sommet, quatre zones e à h concentriques (de l'extérieur à l'intérieur) de largeur décroissante, qui pourront être réalisées par quatre expositions à la lumière d'irradiation successives. La figure montre également la zone 7e à 7h qui est chaque fois irradiée. A chaque exposition, la zone correspondante a été irradiée avec un quart de l'énergie. A la première exposition la taille de la zone irradiée du point était de 80 micromètres, à la seconde exposition de 60 micromètres, aux troisième et quatrième expositions respectivement de 40 et 20 micromètres. Les lignes épaisses et inclinées représentent les épaulements 3 du point après sa réalisation. Le dos 5 de la plaque a été réalisé par exposition par en dessous pour durcir le fond du matériau de plaque afin d'assurer le support des points. Les différentes tailles des points peuvent être réalisées selon un logiciel approprié de traitement de grille d'images connu sous le nom de RIP (Raster Image Processor Software) .Above, the realization of the halftone dots has been described by completion of several passes and thus successive surface sweeps for example by back and forth of a laser beam as a whole. According to the invention, the different scans can also be implemented by using several laser beams operating in parallel, which makes it possible to make only one passage by superimposing the effects of the different lasers in several simultaneous scans. Thus, 48 lasers could be separated into four sections of twelve lasers each with the first section doing the work relating to the first one. passage, the second section doing the work relating to the second pass and so on. Alternatively, only 45 out of 48 lasers could be used, leaving three lasers at rest and grouping the lasers into five sections of nine each. This will allow for a fivefold scan. According to another variant, the lasers could be divided into eight sections of six lasers and eight sweeps at a speed eight times greater. This second embodiment of the invention will be described in more detail below with reference to FIG. 14. FIG. 14 diagrammatically illustrates the pyramidal configuration of a dot marked 1 on a base layer 5. The figure shows, from the base to the top, four zones e to h concentric (from the outside to the inside) of decreasing width, which can be achieved by four exposures to successive irradiation light. The figure also shows the zone 7e to 7h which is each time irradiated. At each exposure, the corresponding area was irradiated with a quarter of the energy. At the first exposure the size of the irradiated area of the point was 80 micrometers, at the second exposure of 60 micrometers, at the third and fourth exposures of 40 and 20 microns, respectively. The thick and inclined lines represent the shoulders 3 of the point after completion. The back of the plate was made by exposure from below to harden the bottom of the plate material to provide point support. The different sizes of the dots can be made according to a suitable image grid processing software known as the Raster Image Processor Software (RIP).
Les figures 15A à 15F illustrent de façon schématique, à titre d'exemple simplifié, la réalisation du point de tramé selon la figure 14, impliquant l'utilisation d'une tête 8 mobile portant huit faisceaux lasers notés 6, le premier faisceau laser étant en bas, le huitième en haut de la rangée inclinée des lasers. La direction de balayage est indiquée par la flèche Fl . La tête laser avance après chaque passage d'un pas de 20 micromètres dans la direction de la flèche F2. Les figures 15A à 15F illustrent les différentes positions de la tête et, par des hachures, l'exposition à la lumière laser effectuée à chacun des six balayages. On constate ainsi que les lignes L4 et L5 (repérées en figure 14) ont reçu quatre fois de la lumière laser dans la zone notée 7H en figure 14, la ligne L3 a été exposée trois fois dans la zone notée 7G en figure 14, la ligne L2 deux fois dans la zone 7f en figure 14 et la ligne Ll une fois dans la zone 7E. Voir également les zones hachurées dans les figures 15 Ceci est valable, de façon symétrique, pour les lignes L6 à L8.FIGS. 15A to 15F schematically illustrate, by way of simplified example, the embodiment of the raster point according to FIG. 14, involving the use of a mobile head 8 carrying eight beams lasers noted 6, the first laser beam being at the bottom, the eighth at the top of the inclined row of lasers. The scanning direction is indicated by the arrow Fl. The laser head advances after each pass a step of 20 micrometers in the direction of the arrow F2. Figures 15A to 15F illustrate the different positions of the head and, by hatching, the exposure to laser light performed at each of the six scans. It is thus found that the lines L4 and L5 (shown in FIG. 14) received four times of the laser light in the zone denoted 7H in FIG. 14, the line L3 was exposed three times in the zone denoted 7G in FIG. line L2 twice in zone 7f in FIG. 14 and line L1 once in zone 7E. See also the hatched areas in FIGS. 15 This is valid, symmetrically, for lines L6 to L8.
La répartition d'énergie réalisée avec ces quatre balayages et lors d'un passage unique permet, après gravure, de générer un épaulement contrôlé du point de trame.The energy distribution performed with these four scans and during a single pass allows, after etching, to generate a controlled shoulder of the raster dot.
La description de l'invention qui vient d'être faite n'a été donnée qu'à titre d'exemple et peut être modifiée de multiples manières à condition de respecter les caractéristiques essentielles de l'invention. Celle- ci propose de façon générale la création de formes imprimantes en relief, pour la flexographie , la typographie et tout autre application similaire. L'invention couvre ainsi également des applications de gaufrage en relief et des applications de type héliogravure. Ces reliefs peuvent être réalisés sur des supports en forme de plaque, de manchon et de cylindres. L'invention couvre l'utilisation de photopolymères mises en œuvre en phase liquide ou semi-liquide ou solide. Les plaques peuvent être avec ou sans semelle, compressibles ou non, sur un support polyester, ou similaire, sur un support acier ou aluminium. Les lasers sont de préférence des diodes en technologie semi-conducteurs. Les lasers sont modulés entre une puissance d'émission lumineuse minimale, le cas échéant zéro, et une puissance maximale nominale. Les passages successifs peuvent se faire à des niveaux de puissance identiques ou différents pour optimiser les résultats. Les plaques peuvent avoir une épaisseur comprise entre 0,4 mm et 6,35 mm environ. Les duretés des plaques manchons ou cylindres réalisées sont typiquement comprises entre environ 25 ShA et 75 ShD. Les plaques peuvent être monocouches ou multicouches . Les densités d'énergie nécessaires pour réticuler les matières photosensibles sont typiquement comprises entre 40 et 1 000 mJ/cm2. Elle est de préférence comprise entre 50 et 150 mJ/cm2. Les lasers sont de préférence des diodes fonctionnant à une longueur d'onde de 405 nm ou avec des longueurs d'onde comprises entre 390 et 410 nm. On peut également appliquer cette méthode à des lasers fonctionnant dans le domaine UV avec des longueurs d'onde de 325 à 375 nm environ. La puissance utile par laser peut varier entre 10 et 300 mW, de préférence entre 10 et 200 mW. La puissance appliquée à chaque module de laser peut être différente par rapport aux autres. La taille des pixels élémentaires utilisés pour balayer la surface de la forme imprimante en relief est typiquement de 6 à 15 micromètres. Le nombre de lasers utilisé est quelconque et peut varier entre 1 et 256 ou même plus selon leur puissance où l'énergie requise pour réticuler la matière. La résolution de l'image est comprise entre environ 1 000 dpi et 8 000 dpi. Les linéatures concernées par les applications vont d'environ 50 lpi à 200 lpi . Le nombre de balayages ou passes successives est compris entre 2 et 16 typiquement, 3 à 4 de préférence, et le nombre de fichiers rippés différents utilisés lors de ces balayages est typiquement de 2 à 5, de préférence 3 ou 4. The description of the invention which has just been given has only been given by way of example and can be modified in many ways provided that the essential characteristics of the invention are respected. This one generally proposes the creation of relief printing forms, for flexography, typography and any other similar application. The invention thus also covers embossing applications in relief and heliogravure type applications. These reliefs can be made on supports in the form of plate, sleeve and cylinders. The invention covers the use of photopolymers implemented in liquid or semi-liquid or solid phase. The plates may be with or without a sole, compressible or not, on a polyester support, or the like, on a steel or aluminum support. The lasers are preferably diodes in semiconductor technology. Lasers are modulated between a minimum light emission power, where appropriate zero, and a nominal maximum power. Successive passes can be at the same or different power levels to optimize the results. The plates may have a thickness of between about 0.4 mm and 6.35 mm. The hardnesses of the formed sleeves or rolls are typically from about ShA to 75 ShD. The plates may be monolayer or multilayer. The energy densities necessary for crosslinking the photosensitive materials are typically between 40 and 1000 mJ / cm 2 . It is preferably between 50 and 150 mJ / cm 2 . The lasers are preferably diodes operating at a wavelength of 405 nm or with wavelengths between 390 and 410 nm. This method can also be applied to lasers operating in the UV range with wavelengths of approximately 325 to 375 nm. The laser power output can vary between 10 and 300 mW, preferably between 10 and 200 mW. The power applied to each laser module may be different from the others. The size of the elementary pixels used to scan the surface of the embossed form is typically 6 to 15 microns. The number of lasers used is arbitrary and can vary between 1 and 256 or even more depending on their power or the energy required to crosslink the material. The resolution of the image is between approximately 1,000 dpi and 8,000 dpi. The lines involved in the applications range from about 50 lpi to 200 lpi. The number of sweeps or successive passes is between 2 and 16 typically, 3 to 4 preferably, and the number of different ripped files used during these scans is typically 2 to 5, preferably 3 or 4.

Claims

REVENDICATIONS
1. Procédé de réalisation d'un agencement à image en relief, utilisable dans des domaines notamment de flexographie, de gaufrage et de héliogravure, et comportant une couche de base et une couche de matériau photosensible fixées sur la couche de base, du type selon laquelle on produit une image sur la couche photosensible en provoquant une réticulation sélective par insolation des zones devant être en relief par la lumière d'une longueur d'ondes prédéterminée, caractérisé en ce que l'on réalise l'image sous forme d'un ensemble de points (1) auxquels on donne une forme sensiblement pyramidale, s 'élargissant en direction de la couche de base (5) . 1. A method of producing a relief image arrangement, usable in areas including flexography, embossing and gravure, and having a base layer and a layer of photosensitive material attached to the base layer, of the type according to an image is produced on the photosensitive layer by selectively cross-linking the areas to be irradiated with light of a predetermined wavelength by irradiation, characterized in that the image is produced in the form of a set of points (1) which is given a substantially pyramidal shape, widening towards the base layer (5).
2. Procédé selon la revendication 1, caractérisé en ce que l'on expose seulement la zone du sommet (2) d'un point d'image (1) à l'énergie de lumière totale, nécessaire pour la réticulation complète de la couche photosensible dans cette zone, et les zones autour du sommet à des fractions de cette énergie, qui diminue dans la direction d'éloignement de la zone de sommet pour que la solubilité du matériau de la couche photosensible dans ces zones augmente en cette direction.2. Method according to claim 1, characterized in that only the area of the apex (2) of an image point (1) is exposed to the total light energy necessary for the complete crosslinking of the layer. photosensitive in this area, and the areas around the apex at fractions of this energy, which decreases in the direction away from the apex area so that the solubility of the photosensitive layer material in these areas increases in this direction.
3. Procédé selon l'une des revendications 1 ou 2, caractérisé en ce qu'un point d'image (1) est réalisé sous forme d'un point de tramé formé par une multitude de pixels .3. Method according to one of claims 1 or 2, characterized in that an image point (1) is formed as a halftone dot formed by a multitude of pixels.
4. Procédé selon l'une des revendications 1 à 3, caractérisé en ce que la lumière d ' insolation de la couche de matériau photosensible est un faisceau laser d'une longueur d'onde comprise entre 390 et 410 nm, de préférence de l'ordre de 405 nm.4. Method according to one of claims 1 to 3, characterized in that the insolation light of the photosensitive material layer is a laser beam with a wavelength between 390 and 410 nm, preferably 405 nm.
5. Procédé selon l'une des revendications 1 à 3, caractérisé en ce que l'on utilise des sources lumineuses fonctionnant dans le domaine UV avec une longueur d'ondes de 325 à 375 nm, ces sources pouvant être des lasers. 5. Method according to one of claims 1 to 3, characterized in that one uses light sources operating in the UV range with a wavelength of 325 to 375 nm, these sources may be lasers.
6. Procédé selon l'une des revendications 3 à 5, caractérisé en ce qu'un point de tramé (1) est formé par exposition successive de zones du point de tailles décroissantes à un niveau d'énergie d'irradiation correspondant à une fraction appropriée de l'énergie nécessaire pour la réticulation totale du matériau photosensible .6. Method according to one of claims 3 to 5, characterized in that a halftone dot (1) is formed by successively exposing areas of the point of decreasing size to a level of irradiation energy corresponding to a fraction appropriate energy necessary for the total crosslinking of the photosensitive material.
7. Procédé selon la revendication 6, caractérisé en ce qu'un point de tramé est réalisé par plusieurs passages aller-retour d'un faisceau laser.7. Method according to claim 6, characterized in that a halftone dot is made by several round trips of a laser beam.
8. Procédé selon la revendication 6, caractérisé en ce qu'un point de tramé est réalisé par différents balayages mis en œuvre en utilisant plusieurs faisceaux laser fonctionnant en parallèle lors d'un même passage. 8. Method according to claim 6, characterized in that a halftone dot is made by different scans implemented using multiple laser beams operating in parallel during a single pass.
9. Procédé selon la revendication 6, caractérisé en ce qu'un point de tramé est réalisé par l'utilisation d'une tête support d'une rangée d'une pluralité de lasers décalés dans la direction perpendiculaire au balayage, qui avance après chaque balayage dans la direction perpendiculaire au balayage d'un pas correspondant à la largeur d'une zone d'exposition différente dans la direction d'avance.9. Method according to claim 6, characterized in that a halftone dot is produced by the use of a support head of a row of a plurality of lasers offset in the direction perpendicular to the scan, which advances after each scanning in the direction perpendicular to the scan by a step corresponding to the width of a different exposure area in the direction of advance.
10. Procédé selon l'une des revendications 3 à 9, caractérisé en ce que la puissance par laser est comprise entre 10 et 300 mW, de préférence entre 10 et 20 mW.10. Method according to one of claims 3 to 9, characterized in that the laser power is between 10 and 300 mW, preferably between 10 and 20 mW.
11. Procédé selon l'une des revendications 3 à 10, caractérisé en ce que la taille des pixels utilisés pour balayer la surface à imager est comprise entre 6 à 15 micromètres . 11. Method according to one of claims 3 to 10, characterized in that the size of the pixels used to scan the surface to be imaged is between 6 to 15 micrometers.
12. Procédé selon l'une des revendications 3 à 11, caractérisé en ce que le nombre de lasers utilisés est avantageusement compris entre 1 et 256.12. Method according to one of claims 3 to 11, characterized in that the number of lasers used is advantageously between 1 and 256.
13. Procédé selon l'une des revendications 3 à 12, caractérisé en ce que la résolution de 1 ' image en relief réalisée est comprise entre 1000 dpi et 8000 dpi. 13. Method according to one of claims 3 to 12, characterized in that the resolution of the embossed image produced is between 1000 dpi and 8000 dpi.
14. Procédé selon l'une des revendications 3 à 13, caractérisé en ce que les linéatures sont comprises entre 60 lpi à 200 lpi.14. Method according to one of claims 3 to 13, characterized in that the lineaments are between 60 lpi to 200 lpi.
15. Procédé selon l'une des revendications 1 à 14, caractérisé en ce qu'on utilise comme support des images en relief des plaques, des manchons et des cylindres.15. Method according to one of claims 1 to 14, characterized in that supports are used as relief images plates, sleeves and cylinders.
16. Procédé selon l'une des revendications 1 à 15, caractérisé en ce qu'on utilise des photopolymères en phase liquide ou semi-liquide ou solide. 16. Method according to one of claims 1 to 15, characterized in that photopolymers are used in liquid or semi-liquid or solid phase.
17. Procédé selon l'une des revendications 1 à 16, caractérisé en ce que l'agencement de support comprend une semelle avantageusement compressible.17. Method according to one of claims 1 to 16, characterized in that the support arrangement comprises an advantageously compressible sole.
18. Procédé selon l'une des revendications 1 à 17, caractérisé en ce que le support est en un matériau tel que du polyester.18. Method according to one of claims 1 to 17, characterized in that the support is of a material such as polyester.
19. Procédé selon l'une des revendications 1 à 17, caractérisé en ce que le support est en métal tel que de l'acier ou aluminium.19. Method according to one of claims 1 to 17, characterized in that the support is made of metal such as steel or aluminum.
20. Agencement à image en relief obtenu selon le procédé selon l'une des revendications 1 à 19, caractérisé en ce qu'il comporte une couche d'un matériau photosensible dont la face extérieure est en relief et formée par des points d'image (1) de forme pyramidale.20. A relief image arrangement obtained according to the method according to one of claims 1 to 19, characterized in that it comprises a layer of a photosensitive material whose outer face is in relief and formed by image points. (1) Pyramidal shape.
21. Agencement selon la revendication 20, caractérisé en ce qu'un point d'image (1) est formé par une pluralité de pixels.Arrangement according to claim 20, characterized in that an image point (1) is formed by a plurality of pixels.
22. Agencement selon l'une des revendications 20 ou 21, caractérisé en ce que la couche photosensible est fixée sur un support (5) . 22. Arrangement according to one of claims 20 or 21, characterized in that the photosensitive layer is fixed on a support (5).
23. Agencement selon la revendication 22, caractérisé en ce que le support est en forme d'une plaque, d'un manchon ou d'un cylindre.23. Arrangement according to claim 22, characterized in that the support is in the form of a plate, a sleeve or a cylinder.
24. Agencement selon la revendication 23, caractérisé en ce que le support est en polyester ou en un métal tel que de l'acier ou de l'aluminium. 24. Arrangement according to claim 23, characterized in that the support is made of polyester or a metal such as steel or aluminum.
25. Agencement selon l'une des revendications 23 ou 24, caractérisé en ce qu'une plaque, manchon ou cylindre a une épaisseur de matériau photosensible comprise entre 0,4 mm et 6,35 mm. 25. Arrangement according to one of claims 23 or 24, characterized in that a plate, sleeve or cylinder has a thickness of photosensitive material between 0.4 mm and 6.35 mm.
26. Agencement selon la revendication 25, caractérisé en ce que les duretés des plaques, manchon ou cylindre sont comprises entre 25 ShA et 75 ShD.Arrangement according to claim 25, characterized in that the hardnesses of the plates, sleeve or cylinder are between ShA and 75 ShD.
27. Agencement selon l'une des revendications 20 à 26, caractérisé en ce que la résolution de l'image est comprise entre 1000 dpi et 8000 dpi.27. Arrangement according to one of claims 20 to 26, characterized in that the resolution of the image is between 1000 dpi and 8000 dpi.
28. Agencement selon l'une des revendications 20 à 27 caractérisé en ce que les linéatures sont comprises entre 50 lpi à 200 lpi .28. Arrangement according to one of claims 20 to 27 characterized in that the lineaments are between 50 lpi 200 lpi.
29. Procédé selon l'une des revendications 7 à 18, caractérisé en ce que les lasers sont modulés en puissance.29. Method according to one of claims 7 to 18, characterized in that the lasers are modulated in power.
30. Procédé selon l'une des revendications 7 à 18, caractérisé en ce que l'on réalise l'image par des balayages multiples lors d'un même passage ou lors de passages successifs avec un pilotage des lasers par des fichiers numériques permettant de moduler l ' énergie totale reçue en chaque point de la plaque en relief à imager pour contrôler les épaulements des zones imprimantes, après gravure, et pour optimiser l'étendue tonale et la tenue des détails 30. Method according to one of claims 7 to 18, characterized in that the image is made by multiple scans during the same passage or during successive passages with a laser control by digital files to modulate the total energy received at each point of the relief plate to be imaged to control the shoulders of the printing areas, after etching, and to optimize the tonal range and the holding of the details
EP08842022A 2007-10-05 2008-10-02 Method of producing a relief image arrangement usable in particular in the field of flexography and arrangement produced according to this method. Withdrawn EP2206019A2 (en)

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FR0758117A FR2921862B1 (en) 2007-10-05 2007-10-05 METHOD FOR PRODUCING A RELIEF-IMAGE ARRAY USED PARTICULARLY IN THE FIELD OF FLEXOGRAPHY AND ARRANGEMENT CARRIED OUT ACCORDING TO THIS METHOD
PCT/FR2008/051787 WO2009053586A2 (en) 2007-10-05 2008-10-02 Method of producing a relief image arrangement usable in particular in the field of flexography and arrangement produced according to this method.

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