JP2010036589A - Device for supplying radiation energy to matter to be printed in lithographic printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device inside a lithographic printer using a printing ink, containing a solvent, which can shorten the drying time for the ink, and a method using the device. <P>SOLUTION: The device with a single radiation energy source supplies radiation energy of a near infrared wavelength to a matter to be printed on the lithographic printer, in such a way that the light from the source hits the matter at a position arranged, after one printing gap, in a printing unit, in its passage of the matter passing in the printer. The radiation energy source of this device substantially emits only the light whose wavelength does not resonate with the adsorptive wavelength of water and falls within the range of 700.00-2,500.00 nm. Thus it is possible to decrease the undesirable drying or the unnecessary heating of the matter to be printed, by supplying the energy within the frequency range while avoiding the absorptive resonance of water. Consequently, the energy suited for the intrinsic drying process of a printing ink is supplied. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention comprises at least one radiant energy source, the light of which strikes a substrate on a path of the substrate through the printing press at a position disposed after at least one printing gap in the printing unit. The present invention relates to an apparatus for supplying near-infrared wavelength radiation energy to a printing medium of a flat printing press.

  Depending on the type of printing ink and the underlying drying process, printing presses, in particular lithographic printing presses for processing sheets or webs, in particular paper, cardboard, cardboard, etc., rotary printing In flat printing presses such as printing presses and offset printing presses, there are various devices that initiate or assist the adhesion of ink on the substrate by supplying radiant energy to the printing ink on the substrate. It is known.

  So-called ultraviolet curable inks are cured by polymerization initiated by photopolymerization with ultraviolet light. On the other hand, there is also a solvent-containing printing ink that can progress both a physical drying process and a chemical drying process. Physical drying includes evaporation of the solvent and diffusion (penetration) into the substrate, whereas chemical drying or oxidative drying is a process of ink that involves oxygen in the air. It is based on the polymerization of oils, resins, binders, etc. contained in the formulation ingredients. Each drying process is generally interdependent. This is because the penetration of the solvent causes separation between the solvent and the resin inside the binder system, thereby causing the resin molecules to approach each other and in some cases to be easily polymerized.

  From EP 0 355 473 A2, an apparatus for drying a printed product is known which comprises a source of radiant energy in the form of a laser. The radiant energy is either at the position between the individual printing units, relative to the surface of the substrate to be traversed through the printing press by the transport device, or before or inside the output device after the last printing unit. Supplied in. At this time, the radiation source may be an ultraviolet laser for ultraviolet curable ink or an infrared laser light source for heating the solvent-containing printing ink. The radiant energy source is arranged outside the printing press in order to prevent the inconvenience that parts of the printing press are heated by unavoidable or unshieldable lost heat. However, the disadvantage in this case is that additional system components must be provided separately to the printer user.

  Further, for example, according to US Pat. No. 6,026,748, a drying apparatus comprising an infrared lamp that emits short-wavelength infrared light (near-infrared light) or medium-wavelength infrared light may be provided in the printing press. It is known. The emission spectrum of the lamp light source is broadband, thus resulting in multiple wavelengths being provided. A disadvantage of this type of infrared drying device is that a significant proportion of energy absorption occurs in the paper and the ink is only heated indirectly. Rapid drying is only possible with a correspondingly high energy injection. However, in such a case, there is a danger that the printing medium may be dried unevenly and may cause a wave.

  In electrophotographic printing engineering, it is known from German Patent Application Publication No. 4435077A1, for example, that fixing of toner on a recording medium is performed by near-infrared radiation energy emitted from a diode laser. By using a narrow band light source, heating of the toner particles is realized, whereby the toner particles are melted, a colored layer is formed, and fixed on the surface of the recording medium. In this spectral region, many types of widely spread paper have a wide range of absorption minimums, so that most of the energy can be absorbed directly by the toner particles.

European Patent Application No. 0355473 US Pat. No. 6,026,748 German Patent Application No. 4435077

  However, the mere knowledge of window-like openings (Fensters) in the absorption spectrum of paper cannot be directly applied to printing engineering using solvent-containing printing ink. As mentioned above, there are other chemical and physical drying processes at the root. In the context of the present invention, the term solvent-containing printing ink refers in particular to a binder system that can be aqueous or organic in nature and that can be subjected to oxidative, ionic or radical polymerization. Means the ink to be used. The energy injection for drying the solvent-containing printing ink is intended to assist or promote the effect of evaporation of the solvent and / or the effect of penetration into the substrate and / or the effect of polymerization, In particular, undesirable incidental phenomena such as excessive heating of the solvent-containing printing ink, which may lead to decomposition of the components and overheating of the solvent, for example, are prevented. Energy injection should not be done just to dissolve the particles, as in the case of toner fixing.

  An object of the present invention is to provide an apparatus inside a flat printing press in which such printing ink is used, which shortens the drying time of the solvent-containing printing ink.

One aspect of an apparatus for supplying radiant energy according to the present invention is as follows.
A substrate comprising at least one radiant energy source (10), the light (12) passing through the printing press at a position (116) located after the at least one printing gap (18) in the printing unit. In an apparatus for supplying radiant energy of a near-infrared wavelength to a printing medium (14) of a flat printing press that hits the printing medium (14) on the path (16) of (14),
The radiant energy source (10) emits substantially only light (12) whose wavelength does not resonate with the absorption wavelength of water (H ₂ O);
The radiant energy source (10) is a semiconductor laser that emits narrow band light (12) having a wavelength between 700.00 nm and 2500.00 nm.

Another aspect of the apparatus for supplying radiant energy according to the present invention is as follows:
A substrate comprising at least one radiant energy source (10), the light (12) passing through the printing press at a position (116) located after the at least one printing gap (18) in the printing unit. In the apparatus for supplying near-infrared wavelength radiant energy to a printing medium (14) of a flat printing press that hits the printing medium (14) on the path (16) of (14), the radiant energy source (10) Substantially emits only light (12) whose wavelength does not resonate with the absorption wavelength of water (H ₂ O),
The radiant energy source (10) is a solid-state laser that emits narrow-band light (12) having a wavelength between 700.00 nm and 2500.00 nm.

  ADVANTAGE OF THE INVENTION According to this invention, the apparatus in the inside of the flat printing press in which such printing ink is used which shortens the drying time of solvent-containing printing ink can be provided.

It is the schematic for demonstrating arrangement | positioning of the apparatus of this invention in a lithographic printing machine. 1 is a schematic diagram showing an advantageous development of the device according to the invention in a lithographic printing press. FIG. 2 is a schematic view showing a lithographic printing machine in which the apparatus of the present invention is arranged in various different ways, such as an arrangement in a plurality of printing units and an arrangement after the last printing unit.

The apparatus of the present invention for supplying near-infrared wavelength radiant energy to a printing plate of a lithographic printing press comprises at least one radiant energy source, the light of which is in at least one printing gap in the printing unit. At a later position, hit the substrate on the path of the substrate through the printing machine, especially the substrate just printed, the radiant energy source is the absorption wavelength of water (H ₂ O) It is characterized by substantially emitting only light that does not resonate with, preferably only such light. The expression that does not resonate with the absorption wavelength of water means that in the context of the present invention, the absorption rate of light energy by water is not higher than 10.0% at 20 degrees Celsius, and in an advantageous embodiment it is higher than 1.0%. It means that it is not high and is 0.1% or less. In the context of the inventive concept, it is preferred that the radiant energy source emits only light of very low intensity and does not emit any light that resonates with the absorption wavelength of water (H ₂ O).

  In an advantageous embodiment, the radiant energy source is narrow band. The radiant energy source at this time emits, for example, with a width of at most ± 50 nm centered on one wavelength, which may be one or more individual spectroscopically narrow emission lines. Furthermore, in an advantageous embodiment, the emission maximum of the narrow-band radiant energy source or the wavelength of the radiant energy is between 700.00 nm and 3000.00 nm, preferably between 700.00 nm and 2500.00 nm, in particular It is between 800.00 nm and 1300.00 nm and is within the range of the so-called window subregion of the absorption spectrum of paper. Emissions of 870.00 ± 50.00 nm and / or 1050.00 nm ± 50.00 nm and / or 1250.00 nm ± 50.00 nm and / or 1600.00 nm ± 50.00 nm are particularly preferred.

The basis of the present invention is the knowledge that the water absorption band contributes to the absorption spectrum of paper. Even with the typical moisture content of lithographic printing without water (without fountain solution), unacceptable energy absorption, which is often unacceptably large, occurs on the print. This absorption is correspondingly greater in lithographic printing using fountain solution. Naturally, too much energy injection into the substrate can be avoided by irradiation with a wavelength that does not resonate with the water absorption line or absorption band (absorption wavelength). In the case of a temperature of 296 K, an absorption interval of 1 m, and 15000 ppm of water, according to the Hiltran data bank, the following absorption by water, more precisely, absorption by water vapor occurs. That is, 0.5% or less at 808 nm, 0.01% or less at 870 ± 10 nm, 10% or less at 940 ± 10 nm, 0.5% or less at 980 ± 10 nm, 0.01% or less at 1030 ± 30 nm, and at 1064 nm 0.01% or less, 0.5% or less at 1100 nm, and 0.01% or less at 1250 ± 10 nm. Paying particular attention to the area of 1 m ² of the printing medium, which is paper, and the air section 1 m above, the air contains an amount of water of about 12 g when the absolute humidity is 1.5%. In the embodiment of the apparatus of the present invention, if the light source is not 1 m or more away from the substrate and the absolute humidity does not clearly exceed 1.5%, the absorption rate by water and / or water vapor listed above is obtained. It will not be exceeded. Additional absorption due to moisture contained in the substrate may occur when light passes through the ink layer and enters the substrate, or by dampening water transferred to the sheet by the printing process.

  Printing depending on the functional groups of the individual components contained in printing inks, especially pigments, colorants or colorants, binders (varnishes), solvents, oils or resins, fillers, auxiliaries, additives or additives Inks can absorb a variety of wavelengths. With the apparatus of the present invention, the printing ink on the printing plate of a lithographic printing machine can be used, for example, by irradiating a small number of wavelengths of a light source that emits one line spectrum while avoiding the absorption wavelength of water. Received infrared light supply.

  As an inventive measure, the printing ink may have an infrared absorber material. Injection of light into the printing ink and / or absorption of radiant energy in the printing ink is generated, enabled, assisted, improved, or facilitated by the infrared absorber material. In the context of the present description of the present invention, only the term assist is used to simplify the text and by this term is meant all stages of action of the infrared absorber material. Energy injection that can cause heat generation leads to rapid drying of the printing ink. On the one hand, a high temperature can be generated in a short time on the printing ink (ink layer) on the substrate, and on the other hand, a chemical reaction can be excited or initiated depending on the composition of the printing ink. Can do. Infrared absorber materials, also called infrared absorbers, IR absorbers, IR absorber materials, etc., on the one hand, may be components of printing inks having functional groups that absorb in the near infrared, and on the other hand Then, it may be an additive or additive added to or mixed in the printing ink before printing. In other words, the printing ink may be supplemented with an infrared absorber material or may contain a component that is modified to an infrared absorber material. At this time, the infrared absorber material has little or no absorption in the visible region of the wavelength because it has little or no effect on the color impression of the printing ink. It is preferable that it has the characteristic that there is no.

  In particular, there is the advantage that relatively high energy injection can be performed directly on the printing ink while being assisted by the infrared absorber material, in which case there is no undesirable energy injection on the substrate. . This is explained, on the one hand, by the reason that light is not directly absorbed by the substrate, and on the other hand, the energy absorbed by the ink layer is not absorbed by the ink within a fraction of a second. This is explained because it is distributed to the printed body. At this time, the heat capacity and the amount ratio are distributed so that the ink layer can be heated in a short time before the temperature of the entire printed sheet increases uniformly and gently. This reduces the overall energy supply required. The selective energy supply is in particular a wavelength that resonates or quasi-resonates with the absorption lines of the components of the printing ink, or a wavelength that resonates or quasi-resonates with the absorption line or absorption maximum of the infrared absorber material in the printing ink. It can be assisted by irradiating. The absorption rate of radiant energy in printing inks is 30% or more, preferably 50%, in particular 75%, even 90% or more.

  Furthermore, preventing energy absorption into water reduces the dryness of the substrate. The reason why this is preferable is that drying of the printing material leads to a change in its format. The substrate to be printed has a different format depending on the dry state or moisture content based on a so-called swelling process. The swelling process between the individual printing units leads to the need for different format plates in the individual printing units. Changes in moisture content between printing units based on the effects of drying caused by radiation will result in errors that cannot be determined and corrected in advance without significant costs. Avoided by ink drying.

  In other words, the apparatus of the present invention makes it possible to dry the solvent-containing printing ink on the substrate without affecting the drying too strongly.

  In order to achieve as narrow a band emission as possible with a high spectral power density at the same time, the radiant energy source is preferably a laser. Alternatively, a broadband light source, such as an IR carbon radiator (IR-Carbonstrahler), with an appropriate filter mechanism so that narrow band radiant energy sources can be obtained in combination can also be used. The filter may in particular be an interference filter. For spatial integration within the lithographic printing machine, the laser is preferably a semiconductor laser (diode laser) or a solid state laser (titanium sapphire, erbium glass, NdYAG, Nd glass, etc.). The solid state laser is preferably optically pumped by a diode laser. The solid state laser may be a fiber laser or an optical waveguide laser, preferably an ytterbium fiber laser capable of providing a light output of 300 to 700 W at 1070 nm to 1100 nm in the workplace. These types of lasers are preferably adjustable within a limited range. In other words, the output wavelength of the laser is variable. Thereby, for example, it is possible to realize adjustment according to a desired wavelength so as to resonate or quasi-resonate with the absorption wavelength of the components in the printing ink, in particular the infrared absorber material in the printing ink.

  A diode laser or a semiconductor laser can be used for the purpose of supplying radiant energy to a printing medium without a separate beam forming optical system, and thus is particularly preferable in connection with the apparatus of the present invention. Since the light emitted from the resonator of the semiconductor laser is extremely divergent, a light beam that spreads as the distance from the exit mirror becomes longer is generated.

In an advantageous development, the device for supplying radiant energy is arranged in a one-dimensional or two-dimensional field (locally curved, totally curved or flat), or a three-dimensional field, and the light is located in multiple positions. And having a plurality of radiant energy sources that hit the substrate. By using a plurality of individual radiant energy sources for individual areas of the substrate, the maximum required radiant energy source output can be kept low. Light sources with low output are usually lower cost and have a longer service life. In addition, generation of unnecessarily high heat loss is prevented. Radiant energy per unit area injected by the supply of energy is 10,000 / cm ² to 100, preferably 500 mJ / cm ² from 1000 mJ / cm ^2, in particular 200 to 100. Irradiation of the printing material is performed for a time of 0.5 ms to 1 s, preferably 1 ms to 50 ms, particularly 5 ms to 25 ms.

  It is particularly preferable that the light hitting the printing medium at one position can be controlled for each radiant energy source independently of the other radiant energy sources with respect to its intensity and exposure time. For this purpose, a control unit may be provided which is independent of or integrated with the machine control of the lithographic printing press. By controlling the radiant energy source parameters, it is possible to adjust the energy supply at different positions of the substrate. In this case, the energy supply can be adjusted according to the covering state of the printing medium at a corresponding position on the printing medium. Furthermore, it is also preferable to set up the device of the invention comprising a plurality of radiant energy sources so that the light of at least two radiant energy sources strikes at one position of the substrate. This may on the one hand be a partially superposed beam bundle and on the other hand a fully superposed beam bundle. In this way, the maximum required output of the individual radiant energy sources is reduced, and there is redundancy when one radiant energy source fails.

  A lithographic printing press according to the invention comprising at least one printing unit is characterized by having the device according to the invention for supplying radiant energy. The lithographic printing machine of the present invention may be a direct or indirect offset printing machine, flexographic printing machine, or the like. On the other hand, the position where the light hits the substrate in the path through the lithographic printing machine may be arranged after the last printing gap of the last printing unit of the plurality of printing units, that is, after all the printing gaps. On the other hand, this position may be arranged after the first printing gap and before the second printing gap, i.e. between at least two printing units.

  A method of supplying radiant energy of near-infrared wavelength to a printing medium with a lithographic printing machine, more precisely, a method of supplying printing ink on the printing medium is also related to the idea of the present invention. In the method of the invention, light from at least one radiant energy source is illuminated onto the substrate, which light is passed through the printing press at a position disposed after at least one printing gap in the printing unit. It hits the substrate to be printed on the path. To assist or enable the printing ink to absorb radiant energy, at least one infrared absorber material is added to the printing ink. In other words, the absorption of radiant energy in the printing ink is assisted by the infrared absorber material added to the printing ink. The infrared absorber material may be synthesized for absorption at a particular wavelength appropriate for the wavelength of the light source, particularly a laser. For the inventive infrared absorber material that absorbs at a specific wavelength, special light sources, in particular lasers, that emit at this specific wavelength can be developed.

  The method of the present invention for supplying radiant energy can, in a preferred manner, be carried out with the apparatus for supplying radiant energy described herein. In particular, as an inventive measure, the emission of the radiant energy source and the absorption of the infrared absorber material are defined, adjusted or set to be compatible with each other. In other words, it is desirable for the radiant energy source to emit a wavelength corresponding to the absorption of the infrared absorber material. That is, it is particularly preferred that the light emitted from the radiation source quasi-resonates with the absorption maximum value of the infrared absorber material, substantially resonates, and particularly resonates. As a result, the absorption of the infrared absorber material The maximum and the emission maximum of the radiation source can be matched as well as possible. The absorption spectrum of the infrared absorber material used has at least 50% of the absorption maximum of the infrared absorber material in the region of emission of the radiation source, preferably at least 75%, in particular at least 90%. Have. The infrared absorber material may have one or more local absorption maxima.

  The method of the present invention for supplying radiant energy can also be referred to as a method of drying the printing ink, a method of assisting the drying of the printing ink, or a method of promoting the drying of the printing ink. Utilizing absorption of infrared absorber material, avoiding the absorption wavelength of water, and at the same time, with less energy absorption to the printing material, especially strong energy absorption to printing ink is realized with very little energy absorption Because. In other words, the method according to the invention makes it possible to dry the solvent-containing printing ink on the substrate without too much influence on the drying.

  The method according to the invention for supplying radiant energy can be implemented particularly advantageously on a lithographic printing press comprising a plurality of printing units on which a plurality of printing inks are printed. At least one of the plurality of printing inks is prepared with an infrared absorber material prior to printing. This preparation can be done before putting the printing ink into the printing unit or inside the printing unit, for example, adding or mixing a certain amount of infrared absorber material to at least one of the plurality of printing inks. be able to. The weight proportion of the infrared absorber material may be less than 10%, preferably less than 3%, in particular less than 1% of the total weight of the printing ink (including the infrared absorber material). When preparing at least two of the plurality of printing inks, use the same infrared absorber material for both printing inks, or use the first infrared absorption for the first printing ink of both printing inks Using a body material, a second infrared absorber material can be used for the second printing ink of both printing inks. The first and second infrared absorber materials can have at least one same or similar absorption maximum, or can have different absorption maximums. The same is true for more than two infrared absorber materials. When the infrared absorber material used has a plurality of different absorption maxima, radiation energy of a plurality of wavelengths can be supplied.

  Next, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic diagram for explaining the arrangement of the apparatus of the present invention in a lithographic printing machine. A radiant energy source 10, in particular a laser, preferably a diode laser or a solid state laser, passes through the lithographic printing machine at a position 116 where the light 12 emitted thereby is located after the printing gap 18. It arrange | positions so that it may contact to the to-be-printed body 14 by the path | route 16 of the to-be-printed body 14. FIG. In FIG. 1, the printing medium 14 is illustrated as a sheet as an example, but the printing medium may be guided to a lithographic printing machine in a web form. The direction of the path 16 of the substrate 14 is indicated by an arrow. This path is shown in a straight line here, without limiting the shape that is generally curved or non-linear, in particular the shape on an arc. The printing gap 18 is defined by the cooperation of the printing cylinder 110 and the impression cylinder 112 in the embodiment shown in FIG. Depending on the specific printing method on the lithographic printing press, the printing cylinder 110 can be a plate cylinder or a blanket cylinder. A printing ink 114 is shown on the non-printing body 14. The light 12 emitted from the radiation source 10 strikes the printing medium 14 at a position 116 in the form of a beam or carpet. The printing ink 114 inside this location 116 can absorb energy from the light 12. By selecting an advantageous wavelength according to the present invention that does not resonate with the absorption wavelength of water, absorption into the substrate 14 is reduced.

  FIG. 2 shows a schematic view of an embodiment of an advantageous development of the device according to the invention in a lithographic printing press. As an example, a field 20 of a radiant energy source 10 is illustrated, in which 3 × 4, i.e. twelve radiation sources 10 are illustrated. In addition to the two-dimensional field 20 shown here, it is also possible to provide a one-dimensional field or a one-dimensional line directed over the entire width of the substrate 14. A two-dimensional field where light strikes the substrate 14 in a two-dimensional distribution is similar to a three-dimensional field, in particular by illuminating a group of positions in parallel in one column of field 20 or simultaneously. There is an advantage that rapid drying is realized. Therefore, the speed at which the printing medium passes by the radiant energy source 10 may be faster than in a one-dimensional field. The field 20 may have other numbers of radiant energy sources 10. Light 12 is supplied to the substrate 14 from each of the plurality of radiant energy sources 10. A position 116 where the light 12 strikes the substrate 14 traveling along the path 16 through the lithographic printing press is located after the printing gap 118 defined by the printing cylinder 110 and the impression cylinder 112. At this time, the individual locations 116 may partially overlap as illustrated for the front row of the radiant energy source 10 in FIG. 2 or may overlap substantially completely. Associated with the field 20 of the radiant energy source 10 is a controller 24 that allows the radiant energy source to exchange control signals via a connection 22. The control device 24 can control the field 20 so that energy is supplied according to the amount of printing ink on the substrate 14 at the position 116.

  FIG. 3 shows a planographic printing machine in which the apparatus of the present invention is arranged in various ways, such as placement in a plurality of printing units, placement after the last printing unit, etc., processing sheets in this embodiment 1 schematically shows a printing press. As an example, this lithographic printing machine includes four printing units 30, a paper feeding device 32, and a paper discharging device 34. Inside the lithographic printing machine 34 are various cylinders which serve on the one hand to guide the sheet through the machine and on the other hand provide a lithographic printing surface, either directly as a plate cylinder or as a blanket cylinder. It is shown. Although not shown in detail, a typical printing unit 30 of a lithographic printing machine further comprises an inking device and optionally a dampening device. Each printing unit 30 includes a printing cylinder 110 and an impression cylinder 112 that define a printing gap 18. A central radiant energy source 36 is shown in the first and second printing units 30, and light emitted from the radiant energy source is transmitted by a light guide member 38 such as an optical waveguide, a mirror, or an imaging optical system. And guided to the projection member 310 attached to the printing unit 30. The projection member 310 emits light 12 at a position 116 disposed after each printing gap 18 of the attached printing unit 30 with respect to the path 16 of the substrate 14 through the planographic printing machine. By using the light guide member 38, the radiant energy source 36 can be arranged at an appropriate position inside the lithographic printing machine where the design space is available. The radiant energy sources 10 are illustrated in the third and fourth printing units 30, and the light 12 emitted from these radiant energy sources is positioned 116 after the printing gap 18 of each printing unit 30. Then, it is directly supplied to the path 16 of the printing medium 14. Further, in the paper discharge device 34, another radiant energy source 312 and a different radiant energy source 314 are illustrated.

  The apparatus of the present invention for supplying radiant energy is similar to that shown in FIG. 3 in a printing machine for processing webs, in particular a so-called web rotary printing machine, according to the configuration shown by the printing machine for processing sheets. Regardless of whether it is for product printing or newspaper printing, it can be advantageously used.

  In one embodiment of the method of the present invention for supplying near-infrared wavelength radiant energy to a substrate, one or more absorption maxima are located in a so-called window of the paper absorption spectrum, in particular water. Infrared absorber materials are used which are suitable by being in the so-called window of the absorption spectrum. The required amount of infrared absorber material is added to the printing ink as an additive or additive. This can be done, for example, by mixing printing ink and infrared absorber material outside or inside the lithographic printing press. Addition is usually meaningful only for so-called chromatic colors, and particularly only for four-color offset printing of yellow, magenta, and cyan (Y, M, and G) colors. In four-color offset printing, the addition for the contrast color, which is a black (K) color, is usually unnecessary. This is because the black printing ink usually absorbs sufficiently well in the important wavelength range from 700 nm to 2500 nm as described in the claims. Nevertheless, additions can be made. The required amount of infrared absorber material is calculated based on the Lambert-Beer extinction law, the layer thickness of the printing ink on the substrate, and the extinction coefficient. The Lambert-Beer extinction law calculation is based on direct resonance in the description herein, ie, the emission wavelength is in the immediate vicinity of the absorption maximum. If the laser wavelengths are slightly different, slightly different absorptions are obtained, and correspondingly more infrared absorber materials are required, especially proportionally more infrared absorber materials. In order to illuminate the substrate, a radiant energy source is used in which the light is substantially resonant with the absorption maximum of the infrared absorber material. In this embodiment, the printing process in the lithographic printing machine can be performed without any other measures and without any difference from the conventional printing method.

In a first example of an embodiment of the method according to the invention, the infrared absorber material is 3-butyl-, whose empirical formula is C ₄₆ H ₅₂ Cl ₂ N ₂ O ₄ and whose molecular weight is 767.84 gmol ^−1. 2 (2-[-2- (3-Butyl-1.1-dimethyl-1,3-dihydro-benzoindole-2-y-lidene) ethylidene] -2-chloro-cyclohex-1-enyl) -ethenyl) -1,1-dimethyl-1H-benzoindolinium perchlorate is used. The structural formula of this infrared absorber material has the following chemical formula:

Represented by This infrared absorber material has an absorption maximum at 819 nm and a maximum extinction of 615276 (mol ^* cm) ⁻¹ . 1.4 weight percent of this infrared absorber material is required for about 90% laser light absorption as an additive in the C, M and Y colors for a layer thickness of 2 μm (Lambert Bale) (Comparison: 0.9 weight percent for about 75% laser absorption, 0.4 weight percent for about 50%, 0.2 weight for about 30%) percent). The apparatus for supplying radiant energy includes a laser that emits at 808 nm as a radiant energy source. For example, a DILAS MB series InGa (Al) As Quantum Well laser can be used. The laser from DILAS has a maximum light output of 24W. The beam geometry after passing through the collimator is 4 mm × 12 mm. Therefore, the emission wavelength is sufficiently resonant with the absorption maximum of 819 ± 15 nm. This infrared absorber material exhibits an absorptance greater than 50%. In this example, at a printing speed of 2 m / s (corresponding to printing of 14400 sheets per hour when the length of the sheet is 50 cm), the energy per unit area of 100 mJ / cm ² and the beam profile of 2 ms. The irradiation time is selected. The absorption rate of radiation by water vapor in the air is 0.5% or less.

In a second example of an embodiment of the method according to the invention, the infrared absorber material is 2 [2- (2) with an empirical formula of C ₄₂ H ₄₄ BClF ₄ N ₂ and a molecular weight of 699.084 gmol ^−1. -[2chloro-3 [2- (3-ethyl-1,3-dihydro-1,1-dimethyl-2H-benzoindole-2-ylidene) -ethylidene] -1cyclohexen-1-yl] -ethenyl) 3- Ethyl-1,1dimethyl-1H-benzoindolinium tetrafluoroborate is used. This infrared absorber material has the following chemical formula:

Represented by This infrared absorber material has an absorption maximum at 816 nm and a maximum quenching of 898704 (mol ^* cm) ⁻¹ . 0.9 weight percent of this infrared absorber material is required for laser light absorption of about 90% as an additive in the C, M and Y colors for a layer thickness of 2 μm (Lambert Bale) (Comparison: 0.5 weight percent for about 75% laser absorption, 0.3 weight percent for about 50%, 0.1 weight for about 30%) percent). The apparatus for supplying radiant energy includes a laser that emits at 808 nm as the radiant energy source, for example, a diode laser HLU 100c 10x12 from LIMO can be used. The LIMO laser has a maximum light output of 100W. The beam geometry after passing through the collimator is 10 mm × 12 mm. Therefore, the emission wavelength is sufficiently resonant with the absorption maximum of 816 ± 15 nm. This infrared absorber material exhibits an absorptance greater than 50%. In this example, the beam profile for energy per unit area of 833 mJ / cm ² at a printing speed of 0.5 m / s (corresponding to printing of 3600 sheets per hour when the length of the sheet is 50 cm) An irradiation time of 40 ms is selected. The absorption rate of radiation by water vapor in the air is 0.5% or less.

In the third example of the embodiment of the method according to the invention, as the infrared absorber material, benzeneaminium- with empirical formula C ₆₂ H ₉₂ Cl ₂ N ₆ O ₈ and molecular weight 1120.37 gmol ⁻¹ N, N′-2,5-cyclohexadiene-1,4-diylidenebis [4- (dibutylamino) -N- [4- (dibutylamino) phenyl] diperchlorate is used. This infrared absorber material has the following chemical formula:

Represented by This infrared absorber material has an absorption maximum at 1064 nm and a maximum extinction of 81300 (mol ^* cm) ⁻¹ . 4.8 weight percent of this infrared absorber material is required for about 50% laser light absorption as an additive in the C, M and Y colors for a layer thickness of 2 μm (Lambert Bale) (Comparison: 15.9 weight percent for about 90% laser absorption, 9.6 weight percent for about 75%, 2.5 weight for about 30%) percent). The apparatus for supplying radiant energy includes a laser emitting at 1075 nm as a radiant energy source. For example, an ytterbium fiber laser YLR-100 manufactured by IPG Photonics can be used. The IPG Photonics laser has a maximum light output of 100W. The beam geometry at the focal point can be 3 mm x 3 mm. Therefore, the emission wavelength is sufficiently resonant with the absorption maximum of 1064 ± 15 nm. This infrared absorber material exhibits an absorptance greater than 50%. In this example, the beam profile and 5 ms of energy per unit area of 417 mJ / cm ² at a printing speed of 2 m / s (corresponding to printing of 14400 sheets per hour when the sheet length is 50 cm). The irradiation time is selected. The absorption rate of radiation by water vapor in the air is 0.1% or less.

In a fourth example of an embodiment of the method according to the invention, the infrared absorber material is bis (3,3 with an empirical formula of C ₃₂ H ₂₆ Cl ₂ NiO ₄ S ₄ and a molecular weight of 732.4 gmol ⁻¹ . 4-Dimethoxy-2'chlorodithiobenzyl) nickel is used. This infrared absorber material has the following chemical formula:

Represented by This infrared absorber material has an absorption maximum at 885 nm and a maximum extinction of 160000 (mol ^* cm) ⁻¹ . 3.2 weight percent of this infrared absorber material is required for approximately 75% laser light absorption as an additive in the C, M and Y colors for a layer thickness of 2 μm (Lambert Bale) (Comparison: 5.3 weight percent for about 90% laser light absorption, 1.6 weight percent for about 50%, 0.8 weight for about 30%) percent). The apparatus for supplying radiant energy includes a laser emitting at 870 nm as the radiant energy source, for example, a Laser2000 fiber coupled laser diode system DLDFC-50 can be used. The Laser 2000 laser has a maximum optical output of 50 W and can be used in either continuous oscillation or pulsed operation. Therefore, the emission wavelength is sufficiently resonant with the absorption maximum of 885 ± 15 nm. This infrared absorber material exhibits an absorptance greater than 50%. In this example, at a printing speed of 2 m / s (corresponding to printing of 14400 sheets per hour when the length of the sheet is 50 cm), the beam profile and 5 ms of energy per unit area of 152 mJ / cm ² are used. The irradiation time is selected. The absorption rate of radiation by water vapor in the air is 0.1% or less.

DESCRIPTION OF SYMBOLS 10 Radiant energy source 12 Light 14 Printed material 16 Path | route 18 Print gap 20 Field 22 Connection part 24 Control apparatus 30 Printing unit 32 Paper feed apparatus 34 Paper discharge apparatus 36 Radiation energy source 38 Light guide member 110 Printing cylinder 112 Impression cylinder 114 Printing Ink 116 Position 310 Projection member 312 Radiant energy source 314 Radiant energy source

Claims (8)

A substrate comprising at least one radiant energy source (10), the light (12) passing through the printing press at a position (116) located after the at least one printing gap (18) in the printing unit. In an apparatus for supplying radiant energy of a near-infrared wavelength to a printing medium (14) of a flat printing press that hits the printing medium (14) on the path (16) of (14),
The radiant energy source (10) emits substantially only light (12) whose wavelength does not resonate with the absorption wavelength of water (H ₂ O);
An apparatus for supplying radiant energy, wherein the radiant energy source (10) is a semiconductor laser emitting a narrow band light (12) having a wavelength between 700.00 nm and 2500.00 nm. A substrate comprising at least one radiant energy source (10), the light (12) passing through the printing press at a position (116) located after the at least one printing gap (18) in the printing unit. In an apparatus for supplying radiant energy of a near-infrared wavelength to a printing medium (14) of a flat printing press that hits the printing medium (14) on the path (16) of (14),
The radiant energy source (10) emits substantially only light (12) whose wavelength does not resonate with the absorption wavelength of water (H ₂ O);
A device for supplying radiant energy, characterized in that the radiant energy source (10) is a solid state laser emitting a narrow band of light (12) whose wavelength is between 700.00 nm and 2500.00 nm.   A plurality of radiant energy sources (wherein the device is arranged in a one-dimensional field, a two-dimensional field (20) or a three-dimensional field, and the light strikes the substrate (14) at a plurality of positions (116)). 10) A device for supplying radiant energy according to claim 1 or 2.   An additional control device (24) is attached to the device, and the light (12) impinging on the substrate (14) at one position (116) is radiated with respect to its intensity and exposure time. 4. A device for supplying radiant energy according to claim 1, wherein the energy source (10) is controllable independently of other radiant energy sources (10).   Any of claims 1 to 4, wherein the wavelength is 870.00 ± 50.00 nm and / or 1050.00nm ± 50.00nm and / or 1250.00nm ± 50.00nm and / or 1600.00nm ± 50.00nm. A device for supplying radiant energy as described in 1.   The apparatus for supplying radiant energy according to any of claims 1 to 5, wherein the light (12) of at least two radiant energy sources (10) strikes the substrate (14) at one position (116).   The position (116) where the planographic printing press of the apparatus has at least two printing units (30) and the light (14) hits the substrate (14) in the path (16) through the planographic printing press. The apparatus for supplying radiant energy according to any of claims 1 to 6, wherein the device is arranged after the last printing gap (18) of the last printing unit (30) of the plurality of printing units.   A lithographic printing machine comprising at least one printing unit (30), characterized in that it comprises a device for supplying radiant energy according to any of claims 1 to 7.

Images