EP1837175B1 - Printing plate and printing unit of a printing press - Google Patents

Printing plate and printing unit of a printing press Download PDF

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Publication number
EP1837175B1
EP1837175B1 EP07005580A EP07005580A EP1837175B1 EP 1837175 B1 EP1837175 B1 EP 1837175B1 EP 07005580 A EP07005580 A EP 07005580A EP 07005580 A EP07005580 A EP 07005580A EP 1837175 B1 EP1837175 B1 EP 1837175B1
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EP
European Patent Office
Prior art keywords
printing
ink
functional layer
dielectric functional
printing forme
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Not-in-force
Application number
EP07005580A
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German (de)
French (fr)
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EP1837175A1 (en
Inventor
Hartmut Fuhrmann
Ralph Dr. Klarmann
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Manroland AG
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Manroland AG
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Publication of EP1837175A1 publication Critical patent/EP1837175A1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C1/00—Forme preparation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41C—PROCESSES FOR THE MANUFACTURE OR REPRODUCTION OF PRINTING SURFACES
    • B41C1/00—Forme preparation
    • B41C1/10—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme
    • B41C1/1058—Forme preparation for lithographic printing; Master sheets for transferring a lithographic image to the forme by providing a magnetic pattern, a ferroelectric pattern or a semiconductive pattern, e.g. by electrophotography

Definitions

  • the invention relates to a printing form. Furthermore, the invention relates to a printing unit of a printing press.
  • Printing form-based printing processes include screen printing, high-pressure, planographic printing and gravure printing, with offset printing in particular being to be expected for lithographic printing.
  • the present invention relates to the field of printing form-based printing processes, in particular the planographic printing processes, which work with erasable and rewritable printing forms.
  • the EP 1 118 470 B1 Figure 1 relates to a printing method with a reusable printing form in which a coating consisting of a hydrophobic thermoplastic material and a hydrophilic binder is applied to a hydrophilic substrate.
  • This applied coating is irradiated imagewise, whereby in the irradiated areas the thermoplastic material fuses with the hydrophilic surface and forms image areas. The unirradiated areas are removed during the printing process, at which point the hydrophilic substrate is uncovered.
  • a rewritable and erasable printing plate for planographic printing which is designed as a lithographic printing plate.
  • the lithographic printing plate disclosed therein has a photoconductor wherein the entire surface of the photoconductor is charged by a charger, and then the photoconductor is exposed to the information to be printed. In the exposed areas of the photoconductor, the charges flow off. In the non-exposed areas, the charges remain on the surface of the photoconductor. The photoconductor then carries a charge image corresponding to the printing information and is brought into contact with printing ink and fountain solution.
  • the fountain solution wets the surface of the photoconductor and the ink can not accumulate.
  • the ink for the image to be printed is deposited in the charge-free regions of the photoconductor.
  • a charging device which generates a homogeneous charge distribution and an exposure device which generates the charge image are required. This also requires a high process engineering effort.
  • the printing form according to the invention has an inner support layer serving for the mechanical stabilization, an outer dielectric functional layer serving for transferring ink and conductive surface elements arranged between the support layer and the functional layer, in particular as electrodes, electrical voltages being applied to the surface elements for zone-by-layer modification the surface energy or surface tension of the functional layer can be applied in such a way that first, ink-conducting regions and second non-ink-conducting regions can be formed on the dielectric functional layer as a function of the voltages applied to the conductive surface elements.
  • the present invention proposes a printing form in which the imaging takes place by applying different electrical voltages to the conductive surface elements of the printing form.
  • the imaging takes place without any material transport alone by applying the different electrical voltages. Therefore, no material has to be removed from the printing plates for deletion. Furthermore, no special charging devices and exposure units are required, so that ultimately the imaging and de-imprinting of the printing form according to the invention can be carried out with very low process outlay.
  • the dielectric functional layer has a dielectric constant greater than or equal to 2 and a thickness less than or equal to 100 microns, wherein the same is formed in particular of a plastic or a ceramic material or a carbon-based material or coated with such a material.
  • the printing unit of a printing press according to the invention is defined in claim 15.
  • Fig. 1 shows a schematic cross section through a printing form according to the invention for the planographic printing, in particular the offset printing, the printing form is writable or imageable and erasable or entndubar and thus reusable.
  • the printing form 10 according to Fig. 1 has an inner substrate or an inner support layer 11 and an outer functional layer 12.
  • the inner support layer 11 is used for mechanical stabilization of the printing form 10 according to the invention, the outer functional layer 12, however, serves to transfer printing ink and thus the printing process.
  • the functional layer 12 is formed from a dielectric material and accordingly designed as a dielectric functional layer.
  • a plurality of conductive surface elements 13 are arranged, which are preferably designed as electrodes.
  • the surface energy or surface tension of the dielectric functional layer 12 can be changed in such a way that the dielectric functional layer 12 depends on the conductive surface elements 13 applied voltages first, color-leading areas and second, non-ink-bearing areas has or forms.
  • each conductive surface element 13 is assigned a switching element 14, by means of which an electrical voltage can be applied to the respective surface element 13 and / or by means of which the magnitude or the size of the respectively applied electrical voltage can be adjusted.
  • an area of the dielectric functional layer 12 adjacent to the surface element 13 is variable with regard to its surface energy in order to form the first, ink-conducting regions and second non-ink-conducting regions of the dielectric functional layer 12.
  • the area of the dielectric functional layer 12 adjacent to the surface element 13 is ink-conducting, whereas if to the surface element 13, a voltage is applied or the voltage applied to the same voltage is greater than a limit value, the area adjacent to the surface element 13 of the dielectric functional layer 12 is not ink-carrying.
  • a material is chosen for the dielectric functional layer 12, which has a low polarity, so that the same is colorless by changing the surface energy by applying electrical voltages to the surface elements 13.
  • the surface elements 13 can be changed with respect to their surface tension or surface energy in such a way that the polar component of the surface tension increases, so that they become non-ink-bearing.
  • a plastic or a ceramic material can be used as a material for the dielectric functional layer 12.
  • a plastic is particularly suitable polyethylene (PE), polypropylene (PP) or polytetrafluoroethylene (PTFE).
  • the dielectric functional layer 12 can also be made of a carbon-based material with high abrasion resistance such.
  • B. polycrystalline or amorphous Diamond Like Carbon (DLC) may be formed. It is also possible to coat the dielectric functional layer on the outside with such a material.
  • the material for the dielectric functional layer 12 is further selected such that the dielectric functional layer 12 has a high relative dielectric constant that is greater than or equal to 2.
  • the dielectric constant of the functional layer 12 is greater than or equal to 10, preferably greater than or equal to 100.
  • the dielectric functional layer 12 preferably has a small layer thickness, so that even by applying low voltages to the surface elements 13, the surface energy or surface tension of the adjacent regions of the dielectric functional layer 12 and thus the wetting properties thereof can be changed.
  • the dielectric functional layer 12 has a thickness of less than or equal to 100 ⁇ m, in particular over a thickness of less than or equal to 50 ⁇ m.
  • the thickness of the dielectric functional layer 12 is preferably less than or equal to 10 ⁇ m.
  • the preferably designed as electrodes, conductive surface elements 13 of the printing form 10 according to the invention are on the one hand electrically insulated from one another with respect to the carrier layer 11 and on the other hand. About unillustrated electrical leads to each of the surface elements 13 an individual electrical voltage can be applied, in conjunction with the switching elements 14.
  • 3 and 4 form the conductive surface elements 13 while a two-dimensional array, wherein the surface elements 13 in the embodiment of the 3 and 4 has a circular surface or border. There are other forms, such. As oval shapes or triangular or star-shaped shapes, for the conductive surface elements 13 possible.
  • the surface property of the dielectric functional layer 12 can be changed such that specifically ink-conducting regions and non-ink-conducting regions of the functional layer 12 can be formed.
  • counter-electrode 15 may be an applicator roll of an inking unit or dampening unit or a transfer cylinder of a printing unit.
  • an electric field is formed between the surface elements 13 to which a voltage is applied and the counterelectrode 15, the electric fields ultimately being the surface energy or surface tension Adjust the dielectric functional layer 12, so as to form the ink-carrying areas and non-ink-carrying areas.
  • an electrical voltage is applied to two surface elements 13, namely to the third surface element seen from the left and to the fifth surface element seen from the left, in which case in the regions 16 of the dielectric functional layer 12 adjacent to these surface elements 13 the surface energy or surface tension is opposite to that other areas of the functional layer 12 is changed.
  • the areas 16 of the dielectric functional layer 12 non-ink-conducting, so that collects on the same fountain solution 17.
  • the functional layer 12 is ink-carrying, so that ink 18 accumulates in these areas.
  • a two-dimensional array of conductive surface elements 13 is arranged under a relatively thin dielectric functional layer 12, wherein the surface elements 13 are preferably designed as controllable electrodes, to each of which a switching element 14 is assigned.
  • An individual electrical voltage can be applied to each of the surface elements 13, so that an individual electric field is formed between the respective surface element 13 and the counterelectrode 15.
  • the surface property, namely surface energy or surface tension, and thus wetting capability of the region of the dielectric functional layer 12 opposite the surface elements 13 can be influenced via the electric field so as to form the ink-carrying regions and non-ink-conducting regions of the printing form in the sense of imaging the same.
  • the carrier layer 11, the dielectric functional layer 12 and the surface elements 13 arranged between the carrier layer 11 and functional layer 12 and switching elements 14 in the sense of a pressure plate or a pressure sleeve as an integral component, which is then positioned on a forme cylinder of a printing unit.
  • the dielectric functional layer 12 it is also possible to design the dielectric functional layer 12 as a separate component, so that it can be separated from the other components of the printing forme, namely the carrier layer 11, the surface elements 13 and switching elements 14 in order to clean or to optionally clean it replace.
  • the carrier layer 11, the surface elements 13 and switching elements 14 into the surface of a forme cylinder.
  • both printing ink and dampening solution are applied to the printing plate by means of applicator rollers, so that an ink-dampening solution emulsion is formed on the surface of the printing form, namely on the dielectric functional layer 12 thereof.
  • an individual electric field forms between the surface elements 13 and the application rollers serving as the counterelectrode 15 in order to define the areas of the printing form in which the printing ink and in which Moisturizer accumulates.
  • an overrunning of the printing plate 10 by an applicator roller and by the transfer cylinder thereby form the above electrical fields in the corresponding transfer nips between the printing plate 10 and the applicator rollers or the transfer cylinder, so that in each transfer nip the defined ink-carrying areas and non-inking Regions of the dielectric functional layer 12 are formed.
  • the distribution of the ink in the ink-carrying areas of the printing plate is not spontaneous, but requires the support of the pressing forces in the transfer nip between the printing plate and the applicator rollers or the transfer cylinder, at the same time the times in which there is also the electric field, which forms the ink-carrying and the non-ink-carrying areas.
  • the new printed image is formed within a relatively short rewetting phase.
  • the size of the non-ink-conducting or ink-conducting regions of the dielectric functional layer 12 can then be defined in the sense of an amplitude-modulated screening in order to be able to reproduce semitones for greater differentiation of a printed image to be printed.
  • the size of the formed by applying an electrical voltage to the surface elements 13 color-leading and non-ink-carrying areas of the dielectric functional layer 12 is therefore in the embodiment of Fig. 2 depends on the magnitude of the voltage applied to them.
  • surface elements 13 which are in accordance with FIG Fig. 5 a plurality of separate or independently controllable and can be acted upon by an electrical voltage areas 19, 20 and 21, respectively. An individual voltage can then be applied to each of these regions 19, 20 or 21 so as to likewise determine the size of the ink-conducting and non-ink-conducting regions of the dielectric functional layer 12 in the sense of amplitude-modulated screening.
  • the areas 19, 20 and 21 are concentrically nested circular rings.
  • other forms of surface elements 13 can be realized, such. B. triangular, square, oval, star-shaped or chain-shaped surface elements.
  • the surface elements 13 for reproducing halftones can also be used in the sense of a so-called dither matrix in conjunction with a corresponding control thereof by covering them with an electrical voltage. Then, if one uses the surface elements 13 in a so-called dither matrix, the number of surface elements depends on the number of distinguishable surface coverages per pixel. Then, when the area elements are combined into a dither matrix, the size of the area of a pixel belonging to a dither matrix is controlled via the electrical voltage at the individual area elements.
  • the surface elements 13 designed as electrodes are arranged in the form of a two-dimensional array on the carrier layer 11 of the printing form 10.
  • the distances between the centers of adjacent surface elements 13 is fixed and not changeable. Since there is a risk of the formation of so-called moiré effects in multicolor, autotypical se-tenant printing, such as a comparison of 3 and 4 can be removed, the arrays of the surface elements 13 have a different angle.
  • the distance between the centers of adjacent surface elements 13 is preferably less than or equal to 1 mm, in particular less than or equal to 200 microns.
  • the printing form 10 according to the invention is preferably used in planographic printing, namely in offset printing, in which case application rollers of an inking unit, application rollers of a dampening unit and the transfer cylinder form counterelectrodes for the surface elements 13 of the printing form 10.
  • a printing press on whose printing units the printing form according to the invention is to be used must have a control device in order to control the individual surface elements 13 of the printing form 10 with corresponding electrical voltages. Then, when a printing press uses the printing form according to the invention, no printing form needs to be changed to change a printed image. To change a print image or to delete and re-imaging of the printing form, only the control of the surface elements must be changed with electrical voltages.
  • the switching elements 14, which serve to control the surface elements 13 designed as electrodes are integrated in the printing form 10.
  • the switching elements 14 for controlling the surface elements 13 are located outside the printing form.

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Printing Methods (AREA)
  • Manufacture Or Reproduction Of Printing Formes (AREA)
  • Printing Plates And Materials Therefor (AREA)
  • Rotary Presses (AREA)

Description

Die Erfindung betrifft eine Druckform. Des Weiteren betrifft die Erfindung ein Druckwerk einer Druckmaschine.The invention relates to a printing form. Furthermore, the invention relates to a printing unit of a printing press.

In der Drucktechnologie unterscheidet man prinzipiell zwischen druckformbasierten Druckverfahren sowie druckformlosen Druckverfahren, wobei die druckformlosen Druckverfahren auch als Non-Impact-Druckverfahren bezeichnet werden. Zu den druckformbasierten Druckverfahren gehören der Siebdruck, Hochdruck, Flachdruck sowie Tiefdruck, wobei zum Flachdruck insbesondere der Offsetdruck zu rechnen ist.In printing technology, a distinction is made in principle between printing form-based printing methods and printing formless printing methods, whereby the printing formless printing methods are also referred to as non-impact printing methods. Printing form-based printing processes include screen printing, high-pressure, planographic printing and gravure printing, with offset printing in particular being to be expected for lithographic printing.

Bei den druckformbasierten Druckverfahren kann zwischen Druckverfahren unterschieden werden, die entweder mit einmal beschreibbaren Druckformen oder mit wiederbeschreibbaren und löschbaren Druckformen arbeiten. Die hier vorliegende Erfindung betrifft das Gebiet der druckformbasierten Druckverfahren, insbesondere der Flachdruckverfahren, die mit löschbaren und wiederbeschreibbaren Druckformen arbeiten.In the case of the printing form-based printing methods, a distinction can be made between printing methods which work either with write-once forms or with rewritable and erasable printing forms. The present invention relates to the field of printing form-based printing processes, in particular the planographic printing processes, which work with erasable and rewritable printing forms.

Aus dem Stand der Technik sind unterschiedliche Ansätze zur Realisierung von löschbaren und wiederbeschreibbaren Druckformen bekannt. So offenbart der Stand der Technik gemäß EP 1 155 871 B1 ein Verfahren zum Behandeln einer löschbaren und wiederbeschreibbaren Druckform, bei welchem mittels eines Inkjets ein farbfreundliches Material auf eine feuchtmittelfreundliche Oberfläche eines Druckformzylinders aufgebracht wird, wobei das aufgebrachte Material getrocknet oder gehärtet und mit einer Bebilderungsvorrichtung, z. B. mit einem Laser, entfernt wird.From the prior art, different approaches to the realization of erasable and rewritable printing forms are known. Thus, the prior art discloses according to EP 1 155 871 B1 a method for treating an erasable and rewritable printing form, wherein by means of an inkjet ink-friendly material is applied to a wettable surface of a printing forme cylinder, wherein the applied material is dried or cured and with an imaging device, for. B. with a laser is removed.

Die EP 1 118 470 B1 1 betrifft ein Druckverfahren mit einer wiederverwendbaren Druckform, bei welchem auf ein hydrophiles Substrat eine Beschichtung aufgebracht wird, die aus einem hydrophoben, thermoplastischen Material und einem hydrophilen Binder besteht. Diese aufgebrachte Beschichtung wird bildweise bestrahlt, wobei in den bestrahlten Bereichen das thermoplastische Material mit der hydrophilen Oberfläche verschmilzt und Bildbereiche ausbildet. Die unbestrahlten Bereiche werden beim Druckvorgang entfernt, wobei an diesen Stellen das hydrophile Substrat freigelegt wird.The EP 1 118 470 B1 Figure 1 relates to a printing method with a reusable printing form in which a coating consisting of a hydrophobic thermoplastic material and a hydrophilic binder is applied to a hydrophilic substrate. This applied coating is irradiated imagewise, whereby in the irradiated areas the thermoplastic material fuses with the hydrophilic surface and forms image areas. The unirradiated areas are removed during the printing process, at which point the hydrophilic substrate is uncovered.

Bei den obigen, aus dem Stand der Technik bekannten Verfahren muss zum Bebildern der Druckformen ein Bebilderungsmaterial auf dieselben aufgetragen werden, welches nach dem Drucken beim Löschen der Druckformen von denselben entfernt werden muss. Dies erfordert einen hohen prozesstechnischen Aufwand.In the above methods known in the art, to image the printing forms, an image-forming material must be applied to them which, after printing, must be removed therefrom upon erasing the printing forms. This requires a high procedural effort.

Aus der EP 1 016 519 B1 ist eine wiederbeschreibbare sowie löschbare Druckplatte für den Flachdruck bekannt, die als Lithographie-Druckplatte ausgeführt ist. Die dort offenbarte Lithographie-Druckplatte verfügt über einen Fotoleiter, wobei die gesamte Oberfläche des Fotoleiters durch eine Aufladungsvorrichtung aufgeladen wird, und wobei anschließend der Fotoleiter mit den zu druckenden Informationen belichtet wird. In den belichteten Bereichen des Fotoleiters fließen die Ladungen ab. In den nicht-belichteten Bereichen bleiben die Ladungen auf der Oberfläche des Fotoleiters bestehen. Der Fotoleiter trägt dann ein der Druckinformation entsprechendes Ladungsbild und wird mit Druckfarbe und Feuchtmittel in Kontakt gebracht. Dort, wo die Ladungen auf dem Fotoleiter verblieben sind, benetzt das Feuchtmittel die Oberfläche des Fotoleiters und die Druckfarbe kann sich nicht anlagern. In den ladungsfreien Bereichen des Fotoleiters lagert sich hingegen die Druckfarbe für das zu druckende Bild an. Für die Funktion dieser Druckplatte sind eine Aufladevorrichtung, die eine homogene Ladungsverteilung erzeugt, und eine Belichtungseinrichtung, die das Ladungsbild erzeugt, erforderlich. Auch dies erfordert einen hohen prozesstechnischen Aufwand.From the EP 1 016 519 B1 is known a rewritable and erasable printing plate for planographic printing, which is designed as a lithographic printing plate. The lithographic printing plate disclosed therein has a photoconductor wherein the entire surface of the photoconductor is charged by a charger, and then the photoconductor is exposed to the information to be printed. In the exposed areas of the photoconductor, the charges flow off. In the non-exposed areas, the charges remain on the surface of the photoconductor. The photoconductor then carries a charge image corresponding to the printing information and is brought into contact with printing ink and fountain solution. Where the charges remain on the photoconductor, the fountain solution wets the surface of the photoconductor and the ink can not accumulate. In contrast, the ink for the image to be printed is deposited in the charge-free regions of the photoconductor. For the function of this printing plate, a charging device which generates a homogeneous charge distribution and an exposure device which generates the charge image are required. This also requires a high process engineering effort.

Hiervon ausgehend liegt der vorliegenden Erfindung das Problem zugrunde, eine neuartige Druckform sowie ein neuartiges Druckwerk einer Druckmaschine zu schaffen. Dieses Problem wird durch eine Druckform gemäß Anspruch 1 gelöst. Die erfindungsgemäße Druckform weist eine innere, der mechanischen Stabilisierung dienende Trägerschicht, eine äußere, dem Übertragen von Druckfarbe dienende dielektrische Funktionsschicht und zwischen der Trägerschicht und der Funktionsschicht angeordnete, insbesondere als Elektroden ausgebildete, leitfähige Flächenelemente auf, wobei an die Flächenelemente elektrische Spannungen zur bereichsweisen Veränderung der Oberflächenenergie bzw. Oberflächenspannung der Funktionsschicht derart anlegbar sind, dass an der dielektrischen Funktionsschicht abhängig von den an die leitfähigen Flächenelemente angelegten Spannungen erste, farbführende Bereiche und zweite, nicht-farbführende Bereiche ausbildbar sind.On this basis, the present invention is based on the problem to provide a novel printing form and a novel printing unit of a printing press. This problem is solved by a printing plate according to claim 1. The printing form according to the invention has an inner support layer serving for the mechanical stabilization, an outer dielectric functional layer serving for transferring ink and conductive surface elements arranged between the support layer and the functional layer, in particular as electrodes, electrical voltages being applied to the surface elements for zone-by-layer modification the surface energy or surface tension of the functional layer can be applied in such a way that first, ink-conducting regions and second non-ink-conducting regions can be formed on the dielectric functional layer as a function of the voltages applied to the conductive surface elements.

Die hier vorliegende Erfindung schlägt eine Druckform vor, bei welcher die Bebilderung durch Anlegen unterschiedlicher elektrischer Spannungen an die leitfähigen Flächenelemente der Druckform erfolgt. Die Bebilderung erfolgt dabei ohne jeglichen Materialtransport alleine durch das Anlegen der unterschiedlichen elektrischen Spannungen. Daher muss auch zum Löschen kein Material von den Druckformen entfernt werden. Weiterhin sind keine speziellen Aufladevorrichtungen sowie Belichtungseinheiten erforderlich, so dass letztendlich mit sehr geringem prozesstechnischen Aufwand die Bebilderung sowie Entbilderung der erfindungsgemäßen Druckform durchgeführt werden kann.The present invention proposes a printing form in which the imaging takes place by applying different electrical voltages to the conductive surface elements of the printing form. The imaging takes place without any material transport alone by applying the different electrical voltages. Therefore, no material has to be removed from the printing plates for deletion. Furthermore, no special charging devices and exposure units are required, so that ultimately the imaging and de-imprinting of the printing form according to the invention can be carried out with very low process outlay.

Vorzugsweise weist die dielektrische Funktionsschicht eine Dielektrizitätskonstante größer oder gleich 2 und eine Dicke kleiner oder gleich 100 µm auf, wobei dieselbe insbesondere aus einem Kunststoff oder einem keramischen Werkstoff oder einem kohlenstoffbasierten Werkstoff gebildet oder mit einem solchen Werkstoff beschichtet ist.Preferably, the dielectric functional layer has a dielectric constant greater than or equal to 2 and a thickness less than or equal to 100 microns, wherein the same is formed in particular of a plastic or a ceramic material or a carbon-based material or coated with such a material.

Das erfindungsgemäße Druckwerk einer Druckmaschine ist in Anspruch 15 definiert.The printing unit of a printing press according to the invention is defined in claim 15.

Bevorzugte Weiterbildungen der Erfindung ergeben sich aus den Unteransprüchen und der nachfolgenden Beschreibung. Ausführungsbeispiele der Erfindung werden, ohne hierauf beschränkt zu sein, an Hand der Zeichnung näher erläutert. Dabei zeigt:

Fig. 1:
einen schematisierten Querschnitt durch eine erfindungsgemäße Druckform,
Fig. 2:
die erfindungsgemäße Druckform der Fig. 1 zusammen mit einer Gegenelektrode,
Fig. 3:
eine Draufsicht auf leitfähige Flächenelemente der erfindungsgemäßen Druckform,
Fig. 4:
eine weitere Draufsicht auf leitfähige Flächenelemente der erfindungsgemäßen Druckform, und
Fig. 5:
eine Draufsicht auf eines der leitfähigen Flächenelemente der erfindungsgemäßen Druckform.
Preferred embodiments of the invention will become apparent from the dependent claims and the description below. Embodiments of the invention will be described, without being limited thereto, with reference to the drawings. Showing:
Fig. 1:
a schematic cross section through a printing form according to the invention,
Fig. 2:
the printing form of the invention Fig. 1 together with a counter electrode,
3:
a top view of conductive surface elements of the printing form according to the invention,
4:
a further plan view of conductive surface elements of the printing form according to the invention, and
Fig. 5:
a plan view of one of the conductive surface elements of the printing form according to the invention.

Fig. 1 zeigt einen schematisierten Querschnitt durch eine erfindungsgemäße Druckform für den Flachdruck, insbesondere den Offsetdruck, wobei die Druckform beschreibbar bzw. bebilderbar sowie löschbar bzw. entbilderbar und damit mehrfach verwendbar ist. Fig. 1 shows a schematic cross section through a printing form according to the invention for the planographic printing, in particular the offset printing, the printing form is writable or imageable and erasable or entbildbar and thus reusable.

Die Druckform 10 gemäß Fig. 1 verfügt über ein inneres Substrat bzw. eine innere Trägerschicht 11 sowie eine äußere Funktionsschicht 12. Die innere Trägerschicht 11 dient der mechanischen Stabilisierung der erfindungsgemäßen Druckform 10, die äußere Funktionsschicht 12 hingegen dient dem Übertragen von Druckfarbe und damit dem Druckverfahren.The printing form 10 according to Fig. 1 has an inner substrate or an inner support layer 11 and an outer functional layer 12. The inner support layer 11 is used for mechanical stabilization of the printing form 10 according to the invention, the outer functional layer 12, however, serves to transfer printing ink and thus the printing process.

Die Funktionsschicht 12 ist aus einem dielektrischen Werkstoff gebildet und demnach als dielektrische Funktionsschicht ausgeführt.The functional layer 12 is formed from a dielectric material and accordingly designed as a dielectric functional layer.

Zwischen der inneren Trägerschicht 11 und der äußeren, dielektrischen Funktionsschicht 12 sind mehrere leitfähige Flächenelemente 13 angeordnet, die vorzugsweise als Elektroden ausgeführt sind. An die leitfähigen Flächenelemente 13 sind elektrische Spannungen anlegbar, über welche bereichsweise bzw. abschnittsweise, angepasst an ein zu druckendes Bild, die Oberflächenenergie bzw. Oberflächenspannung der dielektrischen Funktionsschicht 12 derart verändert werden kann, dass die dielektrische Funktionsschicht 12 abhängig von den an die leitfähigen Flächenelemente 13 angelegten Spannungen erste, farbführende Bereiche sowie zweite, nicht-farbführende Bereiche aufweist bzw. ausbildet.Between the inner carrier layer 11 and the outer, dielectric functional layer 12, a plurality of conductive surface elements 13 are arranged, which are preferably designed as electrodes. The surface energy or surface tension of the dielectric functional layer 12 can be changed in such a way that the dielectric functional layer 12 depends on the conductive surface elements 13 applied voltages first, color-leading areas and second, non-ink-bearing areas has or forms.

Gemäß Fig. 1 ist dabei jedem leitfähigen Flächenelement 13 ein Schaltelement 14 zugeordnet, über welches an das jeweilige Flächenelement 13 eine elektrische Spannung angelegt werden kann und/oder über welches der Betrag bzw. die Grö-ße der jeweils angelegten elektrischen Spannung einstellbar ist.According to Fig. 1 In this case, each conductive surface element 13 is assigned a switching element 14, by means of which an electrical voltage can be applied to the respective surface element 13 and / or by means of which the magnitude or the size of the respectively applied electrical voltage can be adjusted.

Über die an ein leitfähiges Flächenelement 13 angelegte elektrische Spannung ist ein dem Flächenelement 13 benachbarter Bereich der dielektrischen Funktionsschicht 12 hinsichtlich seiner Oberflächenenergie veränderbar, um die ersten, farbführenden Bereiche und zweiten, nicht-farbführenden Bereiche der dielektrischen Funktionsschicht 12 auszubilden. Dabei ist es nach einer ersten Alternative möglich, dass dann, wenn an ein Flächenelement 13 keine Spannung angelegt ist oder die an dasselbe angelegte Spannung kleiner als ein Grenzwert ist, der dem Flächenelement 13 benachbarte Bereich der dielektrischen Funktionsschicht 12 farbführend ist, wohingegen dann, wenn an das Flächenelement 13 eine Spannung angelegt ist oder die an dasselbe angelegte Spannung größer als ein Grenzwert ist, der zum Flächenelement 13 benachbarte Bereich der dielektrischen Funktionsschicht 12 nicht-farbführend ist.By means of the electrical voltage applied to a conductive surface element 13, an area of the dielectric functional layer 12 adjacent to the surface element 13 is variable with regard to its surface energy in order to form the first, ink-conducting regions and second non-ink-conducting regions of the dielectric functional layer 12. In this case, according to a first alternative, it is possible that when no voltage is applied to a surface element 13 or the voltage applied to it is less than a limit value, the area of the dielectric functional layer 12 adjacent to the surface element 13 is ink-conducting, whereas if to the surface element 13, a voltage is applied or the voltage applied to the same voltage is greater than a limit value, the area adjacent to the surface element 13 of the dielectric functional layer 12 is not ink-carrying.

Nach einer zweiten Alternative ist es jedoch auch möglich, dass dann, wenn an das Flächenelement 13 keine Spannung angelegt ist oder die an dasselbe angelegte Spannung kleiner als ein Grenzwert ist, der zum Flächenelement 13 benachbarte Bereich der dielektrischen Funktionsschicht 12 nicht-farbführend ist, wohingegen dann, wenn an das Flächenelement 13 eine Spannung angelegt ist oder die an dasselbe angelegte elektrische Spannung größer als ein Grenzwert ist, der dem Flächenelement 13 benachbarte Bereich der dielektrischen Funktionsschicht 12 farbführend ist. Welche der obigen Altnernativen zum Einsatz kommt, hängt unter anderem von den verwendeten Druckfarben ab.However, according to a second alternative, it is also possible that when no voltage is applied to the sheet 13 or the voltage applied thereto is smaller than a threshold, the portion of the dielectric functional layer 12 adjacent to the sheet 13 is non-ink-bearing, whereas when a voltage is applied to the area element 13 or the voltage applied thereto is greater than a limit value, the region of the dielectric function layer 12 adjacent to the area element 13 is color-carrying. Which of the above alternatives is used depends inter alia on the printing inks used.

Vorzugsweise wird für die dielektrische Funktionsschicht 12 ein Werkstoff gewählt, der eine geringe Polarität aufweist, so dass dieselbe ohne Veränderung der Oberflächenenergie durch Anlegen elektrischer Spannungen an die Flächenelemente 13 farbführend ist. Durch Anlegen einer elektrischen Spannung an Flächenelemente 13 sind den Flächenelementen 13 benachbarte Bereiche hinsichtlich ihrer Oberflächenspannung bzw. Oberflächenenergie derart veränderbar, dass der polare Anteil der Oberflächenspannung steigt, so dass dieselben nicht-farbführend werden.Preferably, a material is chosen for the dielectric functional layer 12, which has a low polarity, so that the same is colorless by changing the surface energy by applying electrical voltages to the surface elements 13. By applying an electrical voltage to surface elements 13, the surface elements 13 can be changed with respect to their surface tension or surface energy in such a way that the polar component of the surface tension increases, so that they become non-ink-bearing.

Als Werkstoff für die dielektrische Funktionsschicht 12 kann dabei ein Kunststoff oder ein keramischer Werkstoff verwendet werden. Als Kunststoff eignet sich insbesondere Polyethylen (PE), Polypropylen (PP) oder Polytetrafluorethylen (PTFE).As a material for the dielectric functional layer 12, a plastic or a ceramic material can be used. As a plastic is particularly suitable polyethylene (PE), polypropylene (PP) or polytetrafluoroethylene (PTFE).

Alternativ kann die dielektrische Funktionsschicht 12 auch aus einem kohlenstoffbasierten Werkstoff mit hoher Abriebbeständigkeit wie z. B. aus polykristallinem oder amorphen Diamond Like Carbon (DLC) gebildet sein. Ebenso ist es möglich, die dielektrische Funktionsschicht außen mit einem solchen Werkstoff zu beschichten.Alternatively, the dielectric functional layer 12 can also be made of a carbon-based material with high abrasion resistance such. B. polycrystalline or amorphous Diamond Like Carbon (DLC) may be formed. It is also possible to coat the dielectric functional layer on the outside with such a material.

Der Werkstoff für die dielektrische Funktionsschicht 12 wird des Weiteren derart gewählt, dass die dielektrische Funktionsschicht 12 eine hohe relative Dielektrizitätskonstante aufweist, die größer oder gleich 2 ist. Insbesondere ist die Dielektrizitätskonstante der Funktionsschicht 12 größer oder gleich 10, vorzugsweise größer oder gleich 100.The material for the dielectric functional layer 12 is further selected such that the dielectric functional layer 12 has a high relative dielectric constant that is greater than or equal to 2. In particular, the dielectric constant of the functional layer 12 is greater than or equal to 10, preferably greater than or equal to 100.

Weiterhin verfügt die dielektrische Funktionsschicht 12 vorzugsweise über eine geringe Schichtdicke, so dass bereits durch Anlegen geringer Spannungen an die Flächenelemente 13 die Oberflächenenergie bzw. Oberflächenspannung der benachbarten Bereiche der dielektrischen Funktionsschicht 12 und damit die Benetzungseigenschaften derselben verändert werden können. Die dielektrische Funktionsschicht 12 verfügt über eine Dicke von kleiner oder gleich 100 µm, insbesondere über eine Dicke von kleiner oder gleich 50 µm. Bevorzugt ist die Dicke der dielektrischen Funktionsschicht 12 kleiner oder gleich 10 µm.Furthermore, the dielectric functional layer 12 preferably has a small layer thickness, so that even by applying low voltages to the surface elements 13, the surface energy or surface tension of the adjacent regions of the dielectric functional layer 12 and thus the wetting properties thereof can be changed. The dielectric functional layer 12 has a thickness of less than or equal to 100 μm, in particular over a thickness of less than or equal to 50 μm. The thickness of the dielectric functional layer 12 is preferably less than or equal to 10 μm.

Die vorzugsweise als Elektroden ausgebildeten, leitfähigen Flächenelemente 13 der erfindungsgemäßen Druckform 10 sind einerseits gegenüber der Trägerschicht 11 und andererseits untereinander elektrisch isoliert. Über nichtdargestellte elektrische Leitungen ist an jedes der Flächenelemente 13 eine individuelle elektrische Spannung anlegbar, und zwar in Verbindung mit den Schaltelementen 14. Gemäß Fig. 3 und 4 bilden die leitfähigen Flächenelemente 13 dabei ein zweidimensionales Array, wobei die Flächenelemente 13 im Ausführungsbeispiel der Fig. 3 und 4 eine kreisrunde Fläche bzw. Umrandung aufweist. Es sind auch andere Formen, so z. B. ovale Formen oder dreieckige oder sternförmige Formen, für die leitfähigen Flächenelemente 13 möglich.The preferably designed as electrodes, conductive surface elements 13 of the printing form 10 according to the invention are on the one hand electrically insulated from one another with respect to the carrier layer 11 and on the other hand. About unillustrated electrical leads to each of the surface elements 13 an individual electrical voltage can be applied, in conjunction with the switching elements 14. According to 3 and 4 form the conductive surface elements 13 while a two-dimensional array, wherein the surface elements 13 in the embodiment of the 3 and 4 has a circular surface or border. There are other forms, such. As oval shapes or triangular or star-shaped shapes, for the conductive surface elements 13 possible.

Wie bereits mehrfach erwähnt, ist über das definierte Anlegen elektrischer Spannungen an die leitfähigen Flächenelemente 13 die Oberflächeneigenschaft der dielektrischen Funktionsschicht 12 derart veränderbar, dass gezielt farbführende Bereiche und nicht-farbführende Bereiche der Funktionsschicht 12 ausgebildet werden können.As already mentioned several times, via the defined application of electrical voltages to the conductive surface elements 13, the surface property of the dielectric functional layer 12 can be changed such that specifically ink-conducting regions and non-ink-conducting regions of the functional layer 12 can be formed.

Dabei wirkt mit den Flächenelementen 13, die als Elektroden ausgebildet sind, eine Gegenelektrode 15 zusammen, wobei die Gegenelektrode 15 von einer auf der Druckform 10 beim Drucken abrollenden Walze bzw. von einem auf der Druckform 10 beim Drucken abrollenden Zylinder gebildet wird. So kann es sich bei der Gegenelektrode 15 um eine Auftragwalze eines Farbwerks bzw. Feuchtwerks oder um einen Übertragungszylinder eines Druckwerks handeln.In this case, interacts with the surface elements 13, which are formed as electrodes, a counter electrode 15, wherein the counter electrode 15 is formed by a rolling on the printing plate 10 during the printing of a roll on the printing plate 10 during printing cylinder. Thus, counter-electrode 15 may be an applicator roll of an inking unit or dampening unit or a transfer cylinder of a printing unit.

Durch das Anlegen definierter elektrischer Spannungen an die als Elektroden ausgebildeten Flächenelemente 13 der Druckform 10 bildet sich zwischen den Flächenelementen 13, an welche eine Spannung angelegt ist, und der Gegenelektrode 15 jeweils ein elektrisches Feld aus, wobei die elektrischen Felder letztendlich die Oberflächenenergie bzw. Oberflächenspannung der dielektrischen Funktionsschicht 12 einstellen bzw. verändern, um so die farbführenden Bereiche und nicht-farbführenden Bereiche auszubilden.By applying defined electrical voltages to the surface elements 13 of the printing forme 10 formed as electrodes, an electric field is formed between the surface elements 13 to which a voltage is applied and the counterelectrode 15, the electric fields ultimately being the surface energy or surface tension Adjust the dielectric functional layer 12, so as to form the ink-carrying areas and non-ink-carrying areas.

In der Darstellung der Fig. 2 ist an zwei Flächenelemente 13, nämlich an das von links gesehen dritte Flächenelement sowie an das von links gesehen fünfte Flächenelement, eine elektrische Spannung angelegt, wobei dann in den zu diesen Flächenelementen 13 benachbarten Bereichen 16 der dielektrischen Funktionsschicht 12 die Oberflächenenergie bzw. Oberflächenspannung gegenüber den anderen Bereichen der Funktionsschicht 12 geändert wird.In the presentation of the Fig. 2 an electrical voltage is applied to two surface elements 13, namely to the third surface element seen from the left and to the fifth surface element seen from the left, in which case in the regions 16 of the dielectric functional layer 12 adjacent to these surface elements 13 the surface energy or surface tension is opposite to that other areas of the functional layer 12 is changed.

So sind im Ausführungsbeispiel der Fig. 2 die Bereiche 16 der dielektrischen Funktionsschicht 12 nicht-farbführend, so dass sich an denselben Feuchtmittel 17 sammelt. In den Bereichen der Funktionsschicht 12, die den Flächenelementen 13 benachbart sind, an welche in Fig. 2 keine elektrische Spannung angelegt ist, ist die Funktionsschicht 12 hingegen farbführend, so dass sich in diesen Bereichen Druckfarbe 18 ansammelt.Thus, in the embodiment of the Fig. 2 the areas 16 of the dielectric functional layer 12 non-ink-conducting, so that collects on the same fountain solution 17. In the areas of the functional layer 12, which are adjacent to the surface elements 13, to which in Fig. 2 no electrical voltage is applied, however, the functional layer 12 is ink-carrying, so that ink 18 accumulates in these areas.

Bei der erfindungsgemäßen Druckform 10 ist demnach unter einer relativ dünnen dielektrischen Funktionsschicht 12 ein zweidimensionales Array aus leitfähigen Flächenelementen 13 angeordnet, wobei die Flächenelemente 13 vorzugsweise als ansteuerbare Elektroden ausgeführt sind, denen jeweils ein Schaltelement 14 zugeordnet ist. An jedes der Flächenelemente 13 ist eine individuelle elektrische Spannung anlegbar, so dass sich zwischen dem jeweiligen Flächenelement 13 und der Gegenelektrode 15 ein individuelles elektrisches Feld ausbildet. Über das elektrische Feld kann letztendlich die Oberflächeneigenschaft, nämlich Oberflächenenergie bzw. Oberflächenspannung, und damit Benetzungsfähigkeit der den Flächenelementen 13 gegenüberliegenden Bereich der dielektrischen Funktionsschicht 12 beeinflusst werden, um so die farbführenden Bereiche und nicht-farbführenden Bereiche der Druckform im Sinne einer Bebilderung derselben auszubilden.Accordingly, in the case of the printing form 10 according to the invention, a two-dimensional array of conductive surface elements 13 is arranged under a relatively thin dielectric functional layer 12, wherein the surface elements 13 are preferably designed as controllable electrodes, to each of which a switching element 14 is assigned. An individual electrical voltage can be applied to each of the surface elements 13, so that an individual electric field is formed between the respective surface element 13 and the counterelectrode 15. Finally, the surface property, namely surface energy or surface tension, and thus wetting capability of the region of the dielectric functional layer 12 opposite the surface elements 13 can be influenced via the electric field so as to form the ink-carrying regions and non-ink-conducting regions of the printing form in the sense of imaging the same.

Es ist möglich, die Trägerschicht 11, die dielektrische Funktionsschicht 12 sowie die zwischen der Trägerschicht 11 und Funktionsschicht 12 angeordneten Flächenelemente 13 sowie Schaltelemente 14 im Sinne einer Druckplatte bzw. eines Drucksleeve als integrales Bauteil auszuführen, welches dann auf einem Formzylinder eines Druckwerks positioniert ist. Im Unterschied hierzu ist es auch möglich, die dielektrische Funktionsschicht 12 als separates Bauteil auszuführen, so dass dieselbe von den übrigen Baugruppen der Druckform, nämlich von der Trägerschicht 11, den Flächenelementen 13 und Schaltelementen 14 getrennt werden kann, um dieselbe gegebenenfalls zu reinigen oder zu ersetzen. Auch ist es möglich, die Trägerschicht 11, die Flächenelemente 13 sowie Schaltelemente 14 in die Oberfläche eines Formzylinders zu integrieren.It is possible to carry out the carrier layer 11, the dielectric functional layer 12 and the surface elements 13 arranged between the carrier layer 11 and functional layer 12 and switching elements 14 in the sense of a pressure plate or a pressure sleeve as an integral component, which is then positioned on a forme cylinder of a printing unit. In contrast to this, it is also possible to design the dielectric functional layer 12 as a separate component, so that it can be separated from the other components of the printing forme, namely the carrier layer 11, the surface elements 13 and switching elements 14 in order to clean or to optionally clean it replace. It is also possible to integrate the carrier layer 11, the surface elements 13 and switching elements 14 into the surface of a forme cylinder.

Beim Drucken mit der erfindungsgemäßen Druckform wird mit Hilfe von Auftragwalzen sowohl Druckfarbe als auch Feuchtmittel auf die Druckform aufgetragen, so dass sich auf die Oberfläche der Druckform, nämlich auf der dielektrischen Funktionsschicht 12 derselben, eine Druckfarbe-Feuchtmittel-Emulsion ausbildet.When printing with the printing form according to the invention, both printing ink and dampening solution are applied to the printing plate by means of applicator rollers, so that an ink-dampening solution emulsion is formed on the surface of the printing form, namely on the dielectric functional layer 12 thereof.

Durch das Anlegen individueller elektrischen Spannungen an die als Elektroden ausgebildeten Flächenelemente 13 der Druckform 10 bildet sich zwischen den Flächenelementen 13 und den als Gegenelektrode 15 dienenden Auftragwalzen jeweils ein individuelles elektrisches Feld aus, um die Bereiche der Druckform festzulegen, in welchen sich Druckfarbe und in welchen sich Feuchtmittel ansammelt. Bei jedem Überrollen der Druckform 10 durch eine Auftragwalze sowie durch den Übertragungszylinder bilden sich dabei in den entsprechenden Übertragungsspalten zwischen der Druckform 10 und den Auftragwalzen bzw. dem Übertragungszylinder die obigen elektrischen Felder aus, so dass in jedem Übertragungsspalt die definierten farbführenden Bereiche und nicht-farbführenden Bereiche der dielektrischen Funktionsschicht 12 ausgebildet sind.By applying individual electrical voltages to the surface elements 13 of the printing forme 10 formed as electrodes, an individual electric field forms between the surface elements 13 and the application rollers serving as the counterelectrode 15 in order to define the areas of the printing form in which the printing ink and in which Moisturizer accumulates. At each overrunning of the printing plate 10 by an applicator roller and by the transfer cylinder thereby form the above electrical fields in the corresponding transfer nips between the printing plate 10 and the applicator rollers or the transfer cylinder, so that in each transfer nip the defined ink-carrying areas and non-inking Regions of the dielectric functional layer 12 are formed.

Da die im Flachdruck zum Einsatz kommende Druckfarbe in der Regel relativ zäh ist, erfolgt die Verteilung der Druckfarbe in die farbführenden Bereiche der Druckplatte nicht spontan, sondern erfordert die Unterstützung der Presskräfte im Übertragungsspalt zwischen der Druckplatte und den Auftragwalzen bzw. dem Übertragungszylinder, gleichzeitig zu den Zeitpunkten, in welchen auch das elektrische Feld besteht, welches die farbführenden und die nicht- farbführenden Bereiche ausbildet. Nach Änderung der elektrischen Ansteuerung der als Elektroden ausgebildeten Flächenelemente 13 bildest sich das neue Druckbild innerhalb einer relativ kurzen Umnetzungsphase aus.Since the ink used in planographic printing is usually relatively tough, the distribution of the ink in the ink-carrying areas of the printing plate is not spontaneous, but requires the support of the pressing forces in the transfer nip between the printing plate and the applicator rollers or the transfer cylinder, at the same time the times in which there is also the electric field, which forms the ink-carrying and the non-ink-carrying areas. After changing the electrical control of the surface elements 13 designed as electrodes, the new printed image is formed within a relatively short rewetting phase.

In der Darstellung der Fig. 2 ist der durch Anlegen einer elektrischen Spannung ausgebildete Bereich 16 der dielektrischen Funktionsschicht 12, der benachbart zum von links gesehen dritten Flächenelement 13 ausgebildet ist, größer als der Bereich 16, der benachbart zum von links gesehen fünften Flächenelement 13 ausgebildet ist. Hierdurch ist dann im Sinne einer amplitudenmodulierten Rasterung die Größe der nicht-farbführenden bzw. farbführenden Bereiche der dielektrischen Funktionsschicht 12 festlegbar, um so zur größeren Differenzierung eines zu druckenden Druckbilds auch Halbtöne wiedergeben zu können.In the presentation of the Fig. 2 is formed by applying an electric voltage formed region 16 of the dielectric functional layer 12, which is adjacent to the third surface element 13 seen from the left, larger than the area 16, which is adjacent to the fifth surface element 13 seen from the left. As a result, the size of the non-ink-conducting or ink-conducting regions of the dielectric functional layer 12 can then be defined in the sense of an amplitude-modulated screening in order to be able to reproduce semitones for greater differentiation of a printed image to be printed.

Die Große der durch Anlegen einer elektrischen Spannung an die Flächenelemente 13 ausgebildeten farbführenden sowie nicht-farbführenden Bereiche der dielektrischen Funktionsschicht 12 ist demnach im Ausführungsbeispiel der Fig. 2 von der Größe der an dieselben angelegten Spannung abhängig.The size of the formed by applying an electrical voltage to the surface elements 13 color-leading and non-ink-carrying areas of the dielectric functional layer 12 is therefore in the embodiment of Fig. 2 depends on the magnitude of the voltage applied to them.

Sollte die hierdurch erzielbare Differenzierung eines Druckbilds nicht ausreichend sein, so können Flächenelemente 13 verwendet werden, die gemäß Fig. 5 mehrere getrennt bzw. unabhängig voneinander ansteuerbare und mit einer elektrischen Spannung beaufschlagbare Bereiche 19, 20 bzw. 21 aufweisen. An jeden dieser Bereiche 19, 20 bzw. 21 kann dann eine individuelle Spannung angelegt werden, um so ebenfalls im Sinne einer amplitudenmodulierten Rasterung die Größe der farbführenden sowie nicht-farbführenden Bereiche der dielektrischen Funktionsschicht 12 festzulegen. Im Ausführungsbeispiel der Fig. 5 handelt es sich bei den Bereichen 19, 20 und 21 um konzentrisch ineinander verschachtelte Kreisringe. Wie bereits oben ausgeführt, sind jedoch auch andere Formen von Flächenelementen 13 realisierbar, so z. B. dreieckige, quadratische, ovale, sternförmige oder kettenförmige Flächenelemente.Should the differentiation of a printed image that can be achieved thereby not be sufficient, it is possible to use surface elements 13 which are in accordance with FIG Fig. 5 a plurality of separate or independently controllable and can be acted upon by an electrical voltage areas 19, 20 and 21, respectively. An individual voltage can then be applied to each of these regions 19, 20 or 21 so as to likewise determine the size of the ink-conducting and non-ink-conducting regions of the dielectric functional layer 12 in the sense of amplitude-modulated screening. In the embodiment of Fig. 5 the areas 19, 20 and 21 are concentrically nested circular rings. As already stated above, however, other forms of surface elements 13 can be realized, such. B. triangular, square, oval, star-shaped or chain-shaped surface elements.

Es sei darauf hingewiesen, dass die Flächenelemente 13 zur Wiedergabe von Halbtönen auch im Sinne einer sogenannten Dithermatrix in Verbindung mit einer entsprechenden Ansteuerung derselben durch Belegen derselben mit einer elektrischen Spannung, verwendet werden können. Dann, wenn man die Flächenelemente 13 in einer sogenannten Dithermatrix verwendet, richtet sich die Anzahl der Flächenelemente nach der Anzahl unterscheidbarer Flächendeckungen pro Pixel. Dann, wenn die Flächenelemente zu einer Dithermatrix zusammengefasst sind, wird über die elektrische Spannung an den einzelnen Flächenelementen die Größe der Fläche eines zu einer Dithermatrix gehörenden Bildpunkts gesteuert.It should be noted that the surface elements 13 for reproducing halftones can also be used in the sense of a so-called dither matrix in conjunction with a corresponding control thereof by covering them with an electrical voltage. Then, if one uses the surface elements 13 in a so-called dither matrix, the number of surface elements depends on the number of distinguishable surface coverages per pixel. Then, when the area elements are combined into a dither matrix, the size of the area of a pixel belonging to a dither matrix is controlled via the electrical voltage at the individual area elements.

Wie bereits erwähnt, sind die als Elektroden ausgebildeten Flächenelemente 13 in Form eines zweidimensionalen Arrays auf der Trägerschicht 11 der Druckform 10 angeordnet. Die Abstände zwischen den Mittelpunkten benachbarter Flächenelemente 13 ist dabei fest und nicht veränderbar. Da beim mehrfarbigen, autotypischen Zusammendruck die Gefahr der Ausbildung sogenannter Moiré-Effekte besteht, können, wie einem Vergleich der Fig. 3 und 4 entnommen werden kann, die Arrays der Flächenelemente 13 eine unterschiedliche Winkelung aufweisen.As already mentioned, the surface elements 13 designed as electrodes are arranged in the form of a two-dimensional array on the carrier layer 11 of the printing form 10. The distances between the centers of adjacent surface elements 13 is fixed and not changeable. Since there is a risk of the formation of so-called moiré effects in multicolor, autotypical se-tenant printing, such as a comparison of 3 and 4 can be removed, the arrays of the surface elements 13 have a different angle.

So verlaufen in Fig. 3 Reihen aus Flächenelementen 13 parallel zu einer durch die Gerade 22 definierten Längsrichtung der Druckform. In Fig. 4 hingegen schließen die Reihen der Flächenelemente 13 gegenüber der Geraden 22 einen relativ spitzen Winkel ein. Werden an dem beim autotypischen Zusammendruck beteiligten Druckwerken Druckplatten mit entsprechend unterschiedlicher Winkelung der zweitdimensionalen Arrays aus den Flächenelementen 13 verwendet, so können die Druckqualität beeinträchtigende Moiré-Effekte vermieden werden.So gone in Fig. 3 Series of surface elements 13 parallel to a defined by the straight line 22 longitudinal direction of the printing form. In Fig. 4 In contrast, the rows of surface elements 13 with respect to the straight line 22 enter a relatively acute angle. If printing plates with a correspondingly different angle of the second-dimensional arrays of the area elements 13 are used on the printing units involved in the autotypical compression, moiré effects impairing the print quality can be avoided.

Es sei darauf hingewiesen, dass der Abstand zwischen den Mittelpunkten benachbarter Flächenelemente 13 vorzugsweise kleiner oder gleich 1 mm, insbesondere kleiner oder gleich 200 µm ist.It should be noted that the distance between the centers of adjacent surface elements 13 is preferably less than or equal to 1 mm, in particular less than or equal to 200 microns.

Die erfindungsgemäße Druckform 10 findet vorzugsweise im Flachdruck, nämlich im Offsetdruck Verwendung, wobei dann Auftragwalzen eines Farbwerks, Auftragwalzen eines Feuchtwerks und der Übertragungszylinder Gegenelektroden für die Flächenelemente 13 der Druckform 10 bilden.The printing form 10 according to the invention is preferably used in planographic printing, namely in offset printing, in which case application rollers of an inking unit, application rollers of a dampening unit and the transfer cylinder form counterelectrodes for the surface elements 13 of the printing form 10.

Eine Druckmaschine, an deren Druckwerken die erfindungsgemäße Druckform verwendet werden soll, muss über eine Steuerungseinrichtung verfügen, um die einzelnen Flächenelemente 13 der Druckform 10 mit entsprechenden elektrischen Spannungen anzusteuern. Dann, wenn eine Druckmaschine die erfindungsgemäße Druckform einsetzt, muss zum Wechsel eines Druckbild keine Druckform gewechselt werden. Zum Ändern eines Druckbilds bzw. zur Löschung und Neubebilderung der Druckform muss lediglich die Ansteuerung der Flächenelemente mit elektrischen Spannungen geändert werden.A printing press on whose printing units the printing form according to the invention is to be used must have a control device in order to control the individual surface elements 13 of the printing form 10 with corresponding electrical voltages. Then, when a printing press uses the printing form according to the invention, no printing form needs to be changed to change a printed image. To change a print image or to delete and re-imaging of the printing form, only the control of the surface elements must be changed with electrical voltages.

Hierzu muss keinerlei Bebilderungsmaterial auf die Druckform aufgetragen werden. Weiterhin sind keinerlei Reinigungsmaßnahmen oder andere mechanische oder chemische Eingriffe am Plattenzylinder bzw. der Druckform erforderlich.For this, no imaging material must be applied to the printing form. Furthermore, no cleaning or other mechanical or chemical interference on the plate cylinder or the printing plate are required.

Weiterhin kann während des Druckvorgangs durch entsprechende Ansteuerung der Flächenelemente der Druckform der Farbton innerhalb weniger Exemplare geregelt werden, um so Druckabweichungen zu korrigieren. So lange sich solche Korrekturen innerhalb gewisser Grenzen bewegen und Änderungen im Farbfluss durch die Speicherfähigkeit des Farbwerks aufgefangen werden können, kann hierdurch eine relativ schnelle Regelung der Farbgebung im Druckprodukt erzielt werden.Furthermore, it is possible to regulate the color tone within a few copies during the printing process by appropriately controlling the surface elements of the printing form in order to correct printing deviations. As long as such corrections are within certain limits and changes in the color flow can be absorbed by the storage capacity of the inking, this can be a relatively fast control of color in the printed product can be achieved.

Im gezeigten Ausführungsbeispiel sind die Schaltelemente 14, die der Ansteuerung der als Elektroden ausgebildeten Flächenelemente 13 dienen, in die Druckform 10 integriert. Im Unterschied hierzu ist es auch möglich, dass sich die Schaltelemente 14 zur Ansteuerung der Flächenelemente 13 außerhalb der Druckform befinden.In the embodiment shown, the switching elements 14, which serve to control the surface elements 13 designed as electrodes, are integrated in the printing form 10. In contrast, it is also possible that the switching elements 14 for controlling the surface elements 13 are located outside the printing form.

BezugszeichenlisteLIST OF REFERENCE NUMBERS

1010
Druckformprinting form
1111
Trägerschichtbacking
1212
Funktionsschichtfunctional layer
1313
Flächenelementsurface element
1414
Schaltelementswitching element
1515
Gegenelektrodecounter electrode
1616
BereichArea
1717
Feuchtmitteldampening solution
1818
Druckfarbeprinting ink
1919
BereichArea
2020
BereichArea
2121
BereichArea
2222
GeradeJust

Claims (15)

  1. A printing forme, namely a printing forme that can be re-imaged and erased, having an inner carrier layer (11) that is used for mechanical stabilization, having an outer dielectric functional layer (12) that is used to transfer printing ink, and having conductive surface elements (13) that are arranged between the carrier layer (11) and the dielectric functional layer (12) and are formed in particular as electrodes and to which electric voltages can be applied to change the surface energy of the dielectric functional layer (12) in regions in such a way that first ink-conveying regions and second non-ink-conveying regions can be formed at the dielectric functional layer (12) as a function of the voltages applied to the conductive surface elements (12).
  2. A printing forme according to claim 1, characterised in that as a function of the voltages applied to the conductive surface elements (12) between the dielectric functional layer and a counter-electrode electric fields are formed as a function of which the first ink-conveying regions and the second non-ink-conveying regions are formed at the dielectric functional layer (12).
  3. A printing forme according to claim 1 or 2, characterised in that associated with each conductive surface element (13) there is at least one respective switching element (14), with the amount or the size of the electric voltage applied to the respective surface element (13) being adjustable by way of the switching element (14).
  4. A printing forme according to one or more of claims 1 to 3, characterised in that by way of the electric voltage that is applied to a conductive surface element (13) a region of the dielectric functional layer (12) that is adjacent to the surface element 13) can be changed with regard to its surface energy in such a way that if no voltage is applied to the surface element (13) or the voltage applied to the same is smaller than a limiting value, the adjacent region of the dielectric functional layer (12) is ink-conveying, whilst if a voltage is applied to the surface element (13) or the voltage applied to the same is greater than a limiting value, the adjacent region of the dielectric functional layer (12) is non-ink-conveying.
  5. A printing forme according to one or more of claims 1 to 3, characterised in that by way of the electric voltage that is applied to a conductive surface element (13) a region of the dielectric functional layer (12) that is adjacent to the surface element 13) can be changed with regard to its surface energy in such a way that if no voltage is applied to the surface element (13) or the voltage applied to the same is smaller than a limiting value, the adjacent region of the dielectric functional layer (12) is non-ink-conveying, whilst if an electric voltage is applied to the surface element (13) or the electric voltage applied to the same is greater than a limiting value, the adjacent region of the dielectric functional layer (12) is ink-conveying.
  6. A printing forme according to one or more of claims 1 to 5, characterised in that the dielectric functional layer (12) has a dielectric constant that is greater than or equal to 2, in particular greater than or equal to 10, preferably greater than or equal to 100.
  7. A printing forme according to one or more of claims 1 to 6, characterised in that the dielectric functional layer (12) has a thickness that is smaller than or equal to 100 µm, in particular is smaller than or equal to 50 µm, preferably is smaller than or equal to 10 µm.
  8. A printing forme according to one or more of claims 1 to 7, characterised in that the dielectric functional layer (12) is formed from a plastics material or from a ceramic material or from a carbon-based material or is coated with such a material.
  9. A printing forme according to one or more of claims 1 to 8, characterised in that the conductive surface elements (13) are electrically insulated on the one hand with respect to the carrier layer (11) and on the other hand with respect to each other, with the conductive surface elements (13) forming a two-dimensional array.
  10. A printing forme according to one or more of claims 1 to 9, characterised in that an interspace between centre points of adjacent conductive surface elements (13) is smaller than or equal to 1 mm, preferably smaller than or equal to 200 µm.
  11. A printing forme according to one or more of claims 1 to 10, characterised in that the conductive surface elements (13) are combined to form a dither matrix.
  12. A printing forme according to one or more of claims 1 to 11, characterised in that an individual electric voltage can act upon each of the conductive surface elements (13) in such a way that the size of the ink-conveying and non-ink-conveying regions of the dielectric functional layer (12) can be determined as a function of the amount or the magnitude of the voltage applied.
  13. A printing forme according to one or more of claims 1 to 12, characterised in that each of the conductive surface elements (13) has a plurality of regions (19, 20, 21), which can be activated separately or independently of each other and upon which an electric voltage can act, in such a way that the size of the non-ink-conveying and ink-conveying regions of the dielectric functional layer (12) can be determined as a function of which of these regions has a voltage acting upon it.
  14. A printing forme according to one or more of claims 1 to 13, characterised in that the dielectric functional layer (12), which is used to transfer printing ink and is in contact with printing ink and dampening agent, is formed in such a way that the same can be separated from the other assemblies of the printing forme, and therefore from the carrier layer (11) and also the surface elements, and thus can be exchanged.
  15. A printing unit of a printing machine, having a forme cylinder on which at least one printing forme is arranged, having an inking unit which by way of at least one application roller applies printing ink to the or each printing forme, having a dampening unit which by way of at least one application roller applies dampening agent to the or each printing forme, and having a transfer cylinder that cooperates with the forme cylinder and transfers the printing ink to a printing material, characterised in that the or each printing forme that is arranged on the forme cylinder is formed in accordance with one or more of claims 1 to 14, with the application rollers and the transfer cylinder forming respective counter-electrodes to the conductive surface elements of the printing forme, in such a way that as a function of the voltages applied to the conductive surface elements electric fields are formed between a counter-electrode formed as an application roller or transfer cylinder and the conductive surface elements which as a function of the rotation of the forme cylinder are located in the region of a transfer gap between the counter-electrode and the forme cylinder, with the dielectric functional layer of the or each printing plate, as a function of these electric fields, having first ink-conveying regions and second non-ink-conveying regions.
EP07005580A 2006-03-22 2007-03-19 Printing plate and printing unit of a printing press Not-in-force EP1837175B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE102006013637A DE102006013637A1 (en) 2006-03-22 2006-03-22 Printing form and printing unit of a printing press

Publications (2)

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EP1837175A1 EP1837175A1 (en) 2007-09-26
EP1837175B1 true EP1837175B1 (en) 2008-10-15

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US (1) US20070221080A1 (en)
EP (1) EP1837175B1 (en)
JP (1) JP2007253621A (en)
CN (1) CN101041309A (en)
DE (2) DE102006013637A1 (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010247407A (en) * 2009-04-15 2010-11-04 Toyo Ink Mfg Co Ltd Printing cylinder, and printing machine using the same
EP2269834A1 (en) 2009-06-30 2011-01-05 WIFAG Maschinenfabrik AG Method and device for modifying the print image of a printing plate
WO2014025164A1 (en) * 2012-08-07 2014-02-13 주식회사 엘지화학 Printed matter and method for manufacturing such printed matter
CN105172325B (en) * 2015-11-05 2017-08-25 武汉大学 It is a kind of to utilize the method for digitizing variable gravure printing roller plate-making
CN107571658B (en) * 2017-09-19 2019-09-20 京东方科技集团股份有限公司 A kind of galley and preparation method thereof
WO2021166114A1 (en) * 2020-02-19 2021-08-26 株式会社秀峰 Printing device and method for manufacturing printed matter

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3730086A (en) * 1970-06-10 1973-05-01 Harris Intertype Corp Printing press film sensor
US4729310A (en) * 1982-08-09 1988-03-08 Milliken Research Corporation Printing method
NL8601376A (en) * 1986-05-29 1987-12-16 Oce Nederland Bv IMAGING ELEMENT FOR AN ELECTROSTATIC PRINTING DEVICE, AND A PRINTING DEVICE APPLYING SUCH AN ELEMENT.
DE3836931C2 (en) * 1988-10-29 1993-11-04 Roland Man Druckmasch PRINT FORM FOR A PRINTING MACHINE WITH REPEATABLE ACTIVATIBLE AND DELETABLE AREAS
US5153618A (en) * 1989-12-29 1992-10-06 Xerox Corporation Ionographic imaging system
US5812170A (en) * 1996-01-29 1998-09-22 Heidelberger Druckmaschinen Ag Electrostatic printing method and apparatus employing a whisker write head
US6078778A (en) * 1997-09-05 2000-06-20 Canon Kabushiki Kaisha Electrifying member comprising an electrically conductive elastomer, and electrophotograph apparatus using said electrifying member
US5927206A (en) * 1997-12-22 1999-07-27 Eastman Kodak Company Ferroelectric imaging member and methods of use
US7121209B2 (en) * 2004-01-16 2006-10-17 Nandakumar Vaidyanathan Digital semiconductor based printing system and method

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DE502007000162D1 (en) 2008-11-27
US20070221080A1 (en) 2007-09-27
EP1837175A1 (en) 2007-09-26
DE102006013637A1 (en) 2007-10-04
CN101041309A (en) 2007-09-26
JP2007253621A (en) 2007-10-04

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