EP0363932A2 - Printing forme - Google Patents

Printing forme Download PDF

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Publication number
EP0363932A2
EP0363932A2 EP89118900A EP89118900A EP0363932A2 EP 0363932 A2 EP0363932 A2 EP 0363932A2 EP 89118900 A EP89118900 A EP 89118900A EP 89118900 A EP89118900 A EP 89118900A EP 0363932 A2 EP0363932 A2 EP 0363932A2
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EP
European Patent Office
Prior art keywords
printing
printing form
toner
ferroelectric
color
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP89118900A
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German (de)
French (fr)
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EP0363932A3 (en
EP0363932B1 (en
Inventor
Hartmut Fuhrmann
Alfred Dr. Hirt
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Manroland AG
Original Assignee
MAN Roland Druckmaschinen AG
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Publication of EP0363932A2 publication Critical patent/EP0363932A2/en
Publication of EP0363932A3 publication Critical patent/EP0363932A3/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
    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41N—PRINTING PLATES OR FOILS; MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
    • B41N1/00—Printing plates or foils; Materials therefor
    • B41N1/006—Printing plates or foils; Materials therefor made entirely of inorganic materials other than natural stone or metals, e.g. ceramics, carbide materials, ferroelectric materials

Definitions

  • the invention relates to a printing form for duplicating an image template with which electrically charged color elements can be transferred to a printing material using an electrostatic field.
  • a printing form of this type is known from DE-AS 19 57 403, in which the printing form essentially consists of a dielectric to which electrodes are assigned.
  • a charge image is generated on the surface of the printing form by means of an ion source and an optically controllable optic, on which charged toner particles are recorded in accordance with the charge image.
  • the toner In contact with a printing material, the toner is transferred from the printing form to the printing material. Since the charge of the printing form is neutralized when the toner is absorbed, the printing form must be activated again before each printing, i. H. the charge image can be generated again.
  • the invention has for its object to improve a printing form of the type mentioned in relation to the prior art in such a way that control of the printing form is required at least between individual printing processes of the same image.
  • the present invention is a printing method using electrically charged toner particles. It has surprisingly been found that multi-color printing is possible in one operation.
  • the ferroelectric material can be polarized differently in very narrow areas, so that when two colors with differently charged particles are used, ie one color is positively charged and the other color is negatively charged, two colors can be applied simultaneously with one print that fewer runs are required for colored prints.
  • the printing form is suitable both for the use of dry toners and for toners contained in a fountain solution as a carrier.
  • Another advantage of the invention results from the fact that the printing form according to the invention is also suitable for gravure printing.
  • the printing form can, according to one embodiment of the invention, consist of a wear-resistant substrate, the surface of which is intended for printing contains gravure cells, the bottoms of which are made of a ferroelectric material.
  • Such a printing form is advantageously connected to a control device with which the ferroelectric bottoms of the cells can be polarized to different extents according to the gray tone of the associated image point.
  • the number of polarized cells is varied in the case of gray tone formation in accordance with autotypical screening; only a binary polarization is necessary for this.
  • the cells that are supposed to take up color are polarized opposite to the color-free areas.
  • the cells are filled with a liquid toner or with a carrier liquid with charged toner particles.
  • the doctor blade or roller that then grazes over the wells acts on the electric field acting on the polarized well base like a counterelectrode, so that a strong electric field arises in the space between the well bottom and the doctor blade, which, depending on the polarization, deposits toner particles on the well bottom or on the doctor blade .
  • the doctoring thus creates a control of the amount of ink or toner in the well.
  • the color the image-filled cell is then transferred to the printing material in accordance with conventional gravure printing.
  • An improvement in the color control by doctoring can be achieved if the doctor is electrically charged or brought to a correspondingly high electrical potential.
  • the printing form is provided with a ferroelectric layer on the surface that comes into contact with the printing material.
  • This printing form is assigned a control which is customary in electrostatic processes and with which the printing form surface is controlled in a matrix-like manner in accordance with an image template, with each pixel being polarized to a greater or lesser extent in accordance with the associated shade of gray or polarized in autotypical screening.
  • the charge image generated in this way can be combined with an ink application brush for a dry toner, with more or less ink being applied to the printing form surface at points.
  • a dry toner a toner (liquid toner) suspended in a carrier liquid can also be used.
  • the printing form according to the invention can also be used in such a way that the toner applied to the charge image using heat, pressure or chemical equipment reaction is fixed on the printing form.
  • the fixed toner serves as an imagewise hydrophobic area for the absorption of oil colors.
  • the toner-free areas are hydrophilic.
  • the printing form according to the invention has the further advantage over the known printing forms that the fixed color areas can be regenerated without renewed activation of the printing form. If the printing time is longer, it is possible that the fixed toner partly comes off, ie the hydrophobic areas have to be regenerated from time to time.
  • the printing form must be activated again in order to regenerate the color areas.
  • the printing form according to the invention is distinguished from the known devices in that a renewed activation for regeneration of the toner areas on the printing form is not necessary here either.
  • FIG. 1 shows a cylindrical printing form 10 with a hollow cylindrical carrier 11 made of electrically conductive material, the surface of which contains a layer 12 made of a ferroelectric material.
  • the ferroelectric layer 12 is controlled accordingly to generate a charge image 15. This can be done using the methods used to control dielectric layers.
  • the charge image consists of the sum of the negatively polarized, the positively polarized and the neutral halftone dots of the ferroelectric material 12.
  • the charges applied to the surface are firmly bound by the alignment of the ferroelectric domains of the material during polarization and form a double layer of charge and counter-charge that can only be separated by strong external fields or high temperature. If the surface comes into contact with electrically charged toner particles, the charge image is not neutralized or the charge flows away. The polarization of the ferroelectrical material remains until the control unit 13 changes it to a different charge pattern.
  • the neutral areas 16 remain free of color toners, while the positive points can attract negatively charged toner particles and the negative points can attract positively charged particles.
  • the possibility of polarities of opposite characters standing closely next to one another on the printing form 10 in turn offers the possibility of recording two different colors by charging one color positively and the other color negatively.
  • FIG. 2 shows the assignment of two toner containers 17 and 18, the one container 10 containing, for example, positively charged yellow toner, while the second container 18 is filled with negatively charged red toner.
  • the toner When passing through the container areas, the toner is brought to the surface of the ferroelectric layer 12 with the aid of brushes 19 and 20, where the color particles adhere to the printing form 10 in accordance with the charge image 15 generated.
  • the absorbed color toner is transferred to a printing material 21 when it comes into contact with it and is fixed thereon by means of a heating source 22.
  • Two colors are applied simultaneously in a printing process, which means that in multi-color printing only half as many printing processes are required for an image than with the conventional methods.
  • the polarization of the ferroelectric layer can be done continuously with plus and minus, ie without neutral positions 16. Different shades of gray are either generated by different field strengths, with which the amount of color to be attracted can be varied, or by autotypical ones Screening with screen spots of different sizes, but polarized to saturation. Instead of a dry toner, charged toner particles suspended in a carrier liquid can also be used.
  • the rotogravure form consists of a substrate 30 made of a wear-resistant metal or ceramic.
  • the printing form contains pressure cups 31 arranged on the surface in a grid-like manner, the bottom of which each has a ferroelectric layer 32.
  • the individual ferroelectric layers 32 within the well 31 are actuated in an imagewise manner.
  • the cups 31 are then filled with a liquid toner 33.
  • the toner particles therein are positively charged, for example, while the surface of the ferroelectric material 32 is more or less negatively polarized.
  • the excess liquid 33 is wiped off by means of a doctor blade 34.
  • the doctor blade 34 receives a nagative charge, which makes it possible, depending on the intensity of the polarity of the ferroelectric material 32, to simultaneously pull corresponding amounts of particles out of the cells when crossing the cells 31. Thereafter, a quantity of color pigments remains in the cells, which correspond to the respective field strength of the assigned ferroelectric material 32. The remaining amount of color particles finally corresponds to the desired shade of gray. Finally, the amount of ink metered in this way is transferred to the printing material 35. Without renewed activation, the wells 31 are filled with colored liquid again.
  • the printing form according to the invention is suitable both for printing presses and for other duplicating devices, such as copiers.

Abstract

For the formation of an electrostatically operating printing forme having a permanent loading image, it is proposed to provide the printing forme (10) with a ferroelectric coating 12 which can be activated by means of conventional methods (13, 14) to generate a loading image (15). A loading image of this type is not only permanent, but it can also be generated in such a way that two colours, loaded with different characters, can be transferred simultaneously in one printing process. The ferroelectric material is also suitable for the formation of intaglio printing formes in that it forms the base of the respective intaglio printing cup. <IMAGE>

Description

Die Erfindung bezieht sich auf eine Druckform zum Verviel­fältigen einer Bildvorlage, mit der elektrisch geladene Farbelemente unter Nutzung eines elektrostatischen Feldes auf einen Bedruckstoff übertragbar sind.The invention relates to a printing form for duplicating an image template with which electrically charged color elements can be transferred to a printing material using an electrostatic field.

Eine Druckform dieser Art ist aus der DE-AS 19 57 403 be­kannt, bei der die Druckform im wesentlichen aus einem Dielektrikum besteht, dem Elektroden zugeordnet sind. Mittels einer Ionenquelle und einer bildmäßig ansteuerbaren Optik wird auf der Oberfläche der Druckform ein Ladungsbild erzeugt, worauf geladene Tonerpartikel entsprechend dem Ladungsbild aufgenommen werden. Im Kontakt mit einem Bedruckstoff wird der Toner von der Druckform auf den Bedruckstoff übertragen. Da die Ladung der Druckform bei Aufnahme des Toners neutralisiert wird, muß vor jedem Druck die Druckform erneut angesteuert, d. h. das Ladungsbild erneut erzeugt werden.A printing form of this type is known from DE-AS 19 57 403, in which the printing form essentially consists of a dielectric to which electrodes are assigned. A charge image is generated on the surface of the printing form by means of an ion source and an optically controllable optic, on which charged toner particles are recorded in accordance with the charge image. In contact with a printing material, the toner is transferred from the printing form to the printing material. Since the charge of the printing form is neutralized when the toner is absorbed, the printing form must be activated again before each printing, i. H. the charge image can be generated again.

Der Erfindung liegt die Aufgabe zugrunde, eine Druckform der eingangs genannten Art gegenüber dem Stand der Technik dahingehend zu verbessern, daß eine Ansteuerung der Druck­form zumindest zwischen einzelnen Druckprozessen desselben Bildes erforderlich ist.The invention has for its object to improve a printing form of the type mentioned in relation to the prior art in such a way that control of the printing form is required at least between individual printing processes of the same image.

Die Aufgabe wird erfindungsgemäß durch die Merkmale des Anspruchs 1 gelöst.The object is achieved by the features of claim 1.

Durch die Verwendung eines ferroelektrischen Materials für den Aufbau eines Ladungsbildes ist es gelungen, das einmal erzeugte Ladungsbild für die gesamte Auflage einer Bildvorlage aufrechtzuerhalten, ohne Zwischenansteuerungs­vorgänge durchführen zu müssen. Die einmal angesteuerte Druckform nimmt beim Durchgang des Farbwerkes den Toner auf und gibt diesen an einen Bedruckstoff ab, wobei das Ladungs­bild aufrechterhalten bleibt.Through the use of a ferroelectric material for the construction of a charge pattern, it has been possible to generate the charge pattern once it has been produced for the entire edition Maintain image template without having to perform intermediate control operations. The printing form, once actuated, picks up the toner as it passes through the inking unit and releases it to a printing material, the charge image being maintained.

Aus der DE-36 33 758 A1 ist zwar die Einführung von ferro­elektrischen Materialien in Druckmaschinen bekannt geworden, bei der darin beschriebenen Anwendung erfolgt jedoch keine Nutzung des elektrischen Feldes. Die bekannte Anlage bezieht sich vielmehr auf den konventionellen Offsetdruck mit Öl­farben und Feuchtmitteln. Bei diesem bekannten Verfahren wird die Eigenschaft genutzt, oaß unterschiedlich polari­sierte Stellen des ferroelektrischen Materials unterschied­liche Affinitäten für Öl und Wasser haben.From DE-36 33 758 A1 the introduction of ferroelectric materials in printing presses has become known, but in the application described therein there is no use of the electric field. The well-known system rather refers to conventional offset printing with oil colors and dampening solutions. This known method uses the property that differently polarized points of the ferroelectric material have different affinities for oil and water.

Bei der vorliegenden Erfindung dagegen geht es um ein Druck­verfahren, bei dem elektrisch geladene Tonerpartikel ver­wendet werden. Es hat sich hierbei überraschenderweise herausgestellt, daß in einem Arbeitsgang ein Mehrfarben­druck möglich ist. Das ferroelektrische Material läßt sich in sehr engen Bereichen unterschiedlich polarisieren, so daß bei Anwendung von zwei Farben mit unterschiedlich geladenen Partikeln, d. h., daß die eine Farbe positiv und die andere Farbe negativ geladen ist, mit einem Druck gleichzeitig zwei Farben aufgebracht werden können, so daß bei farbigen Drucken geringere Durchlaufzahlen notwendig sind.The present invention, on the other hand, is a printing method using electrically charged toner particles. It has surprisingly been found that multi-color printing is possible in one operation. The ferroelectric material can be polarized differently in very narrow areas, so that when two colors with differently charged particles are used, ie one color is positively charged and the other color is negatively charged, two colors can be applied simultaneously with one print that fewer runs are required for colored prints.

Die Druckform eignet sich sowohl zur Anwendung von trocke­nen Tonern als auch für in einem Feuchtmittel als Träger enthaltenen Toner. Ein weiterer Vorteil der Erfindung ergibt sich dadurch, daß die erfindungsgemäße Druckform ebenfalls für den Tiefdruck geeignet ist. Hierzu kann die Druckform gemäß einer Ausgestaltung der Erfindung aus einem ver­schleißfesten Substrat bestehen, dessen für den Druck vorgesehene Oberfläche Tiefdrucknäpfchen enthält, deren Böden aus einem ferroelektrischen Material bestehen.The printing form is suitable both for the use of dry toners and for toners contained in a fountain solution as a carrier. Another advantage of the invention results from the fact that the printing form according to the invention is also suitable for gravure printing. For this purpose, the printing form can, according to one embodiment of the invention, consist of a wear-resistant substrate, the surface of which is intended for printing contains gravure cells, the bottoms of which are made of a ferroelectric material.

Eine derartige Druckform wird vorteilhaft mit einer Ansteuereinrichtung verbunden, mit der die ferroelektrischen Böden der Näpfchen entsprechend dem Grauton des zuge­hörigen Bildpunktes unterschiedlich stark polarisiert werden können. Bei Grauntonbildung gemäß autotypischer Rasterung wird die Anzahl der polarisierten Näpfchen variiert, hierzu ist nur eine binäre Polarisierung nötig.Such a printing form is advantageously connected to a control device with which the ferroelectric bottoms of the cells can be polarized to different extents according to the gray tone of the associated image point. The number of polarized cells is varied in the case of gray tone formation in accordance with autotypical screening; only a binary polarization is necessary for this.

Vorteilhaft werden die Näpfchen, die Farbe aufnehmen sollen, entgegengesetzt zu den farbfreien Bereichen polarisiert. Nach der Ansteuerung werden die Näpfchen mit einem Flüssig­toner bzw. mit einer Trägerflüssigkeit mit geladenen Tonerpartikeln gefüllt. Die anschließend über die Näpfchen streifende Rakel bzw. Rolle wirkt auf das an den polari­sierten Näpfchenboden wirksame elektrische Feld wie eine Gegenelektrode, so daß im Raum zwischen Näpfchenboden und Rakel ein starkes elektrisches Feld entsteht, das je nach Polarisierung Tonerpartikel am Näpfchenboden oder an der Rakel ablagert. Durch das Abrakeln entsteht somit eine Steuerung der Farb- bzw. Tonermenge im Näpfchen. Die Farbe der bildmäßig gefüllten Näpfchen wird dann entsprechend der konventionellen Tiefdrucktechnik auf den Bedruckstoff übertragen.Advantageously, the cells that are supposed to take up color are polarized opposite to the color-free areas. After activation, the cells are filled with a liquid toner or with a carrier liquid with charged toner particles. The doctor blade or roller that then grazes over the wells acts on the electric field acting on the polarized well base like a counterelectrode, so that a strong electric field arises in the space between the well bottom and the doctor blade, which, depending on the polarization, deposits toner particles on the well bottom or on the doctor blade . The doctoring thus creates a control of the amount of ink or toner in the well. The color the image-filled cell is then transferred to the printing material in accordance with conventional gravure printing.

Eine Verbesserung der Farbsteuerung durch Abrakeln ist erreichbar, falls die Rakel elektrisch aufgeladen bzw. auf entsprechend hohes elektrisches Potential gebracht wird.An improvement in the color control by doctoring can be achieved if the doctor is electrically charged or brought to a correspondingly high electrical potential.

Für übrige, insbesondere elektrostatische Flachdruckver­fahren wird die Druckform an der mit dem Bedruckstoff in Kontakt kommenden Oberfläche mit einer ferroelektrischen Schicht versehen. Dieser Druckform wird eine in elektro­statischen Verfahren übliche Ansteuerung zugeordnet, mit der die Druckformoberfläche matrixartig entsprechend einer Bildvorlage angesteuert wird, wobei jeder Bildpunkt ent­sprechend dem zugehörigen Grauton entweder stärker oder weniger stark polarisiert oder in autotypischer Rasterung polarisiert wird. Das so erzeugte Ladungsbild kann mit einer Farbauftragbürste für einen Trockentoner in Verbindung gesetzt werden, wobei punktweise mehr oder weniger Farbe auf die Druckformoberfläche aufgetragen wird. Beim Kontakt der mit Farbton beladenen Oberfläche der Druckform mit einem Bedruckstoff und einer Gegenelektrode wird die Farbe auf den Bedruckstoff übertragen. Anstelle eines trockenen Toners kann gleichfalls ein in einer Trägerflüssigkeit suspendier­ter Toner (Flüssigtoner) verwendet werden.For other, in particular electrostatic, planographic printing processes, the printing form is provided with a ferroelectric layer on the surface that comes into contact with the printing material. This printing form is assigned a control which is customary in electrostatic processes and with which the printing form surface is controlled in a matrix-like manner in accordance with an image template, with each pixel being polarized to a greater or lesser extent in accordance with the associated shade of gray or polarized in autotypical screening. The charge image generated in this way can be combined with an ink application brush for a dry toner, with more or less ink being applied to the printing form surface at points. When the surface of the printing form loaded with color comes into contact with a printing material and a counter electrode, the color is transferred to the printing material. Instead of a dry toner, a toner (liquid toner) suspended in a carrier liquid can also be used.

Die erfindungsgemäße Druckform kann auch derart verwendet werden, daß der auf das Ladungsbild aufgebrachte Toner unter Anwendung von Wärme, Druck oder chemischen Anlage­ rungsreaktionen auf der Druckform fixiert wird. Hier dient der fixierte Toner als bildmäßiger hydrophober Bereich zur Aufnahme von Ölfarben. Die tonerfreien Bereiche sind hydro­phil. In diesem Verfahren hat die erfindungsgemäße Druckform gegenüber den bekannten Druckformen den weiteren Vorteil, daß die fixierten Farbbereiche ohne erneute Ansteuerung der Druckform regeneriert werden können. Bei längerer Druckzeit ist es möglich, daß der fixierte Toner sich zum Teil löst, d. h. die hydrophoben Bereiche müssen von Zeit zu Zeit regeneriert werden. Bei den bekannten Druckformen mit di­elektrischen Schichten muß zur Regenerierung der Farb­bereiche die Druckform erneut angesteuert werden. Hier zeichnet sich die erfindungsgemäße Druckform gegenüber den bekannten Einrichtungen dadurch aus, daß auch hierbei eine erneute Ansteuerung für eine Regenerierung der Tonerbe­reiche auf der Druckform nicht notwendig ist.The printing form according to the invention can also be used in such a way that the toner applied to the charge image using heat, pressure or chemical equipment reaction is fixed on the printing form. Here the fixed toner serves as an imagewise hydrophobic area for the absorption of oil colors. The toner-free areas are hydrophilic. In this process, the printing form according to the invention has the further advantage over the known printing forms that the fixed color areas can be regenerated without renewed activation of the printing form. If the printing time is longer, it is possible that the fixed toner partly comes off, ie the hydrophobic areas have to be regenerated from time to time. In the known printing forms with dielectric layers, the printing form must be activated again in order to regenerate the color areas. Here, the printing form according to the invention is distinguished from the known devices in that a renewed activation for regeneration of the toner areas on the printing form is not necessary here either.

Die Erfindung wird anhand der Zeichnung näher beschrieben. Es zeigen:

  • Fig. 1 bis 3 ein Verfahrensfolge gemäß einem ersten Aus­führungsbeispiel und
  • Fig. 4 bis 6 eine Folge eines zweiten Ausführungs­beispieles.
The invention is described in more detail with reference to the drawing. Show it:
  • 1 to 3 a process sequence according to a first embodiment and
  • 4 to 6 a sequence of a second embodiment.

In Fig. 1 ist eine zylinderförmige Druckform 10 mit einem hohlzylindrischen Träger 11 aus elektrisch leitendem Mate­rial gezeigt, dessen Oberfläche eine Schicht 12 aus einem ferroelektrischen Material enthält. Mittels eines an eine konventionelle Steuereinheit 13 gekoppelten Druckkopfes 14 und den als Elektrode ausgebildeten Träger 11 wird die ferroelektrische Schicht 12 zur Erzeugung eines Ladungsbil­des 15 entsprechend angesteuert. Dieses kann mit den Methoden erfolgen, wie sie zur Ansteuerung von dielekt­rischen Schichten verwendet werden. Das Ladungsbild besteht aus der Summe der negativ polarisierten, der positiv polari­sierten und der neutralen Rasterpunkte des ferroelektrischen Materials 12. Die auf die Oberfläche aufgebrachten Ladungen sind durch die Ausrichtung der ferroelektrischen Domänen des Materials bei der Polarisierung fest gebunden und bilden eine Doppelschicht von Ladung und Gegenladung, die nur durch starke äußere Felder oder hohe Temperatur getrennt werden kann. Wenn die Oberfläche in Kontakt mit elektrisch gelade­nen Tonerpartikeln kommt, findet keine Neutralisierung des Ladungsbildes bzw. ein Abfließen der Ladung statt. Die Polarisierung des ferroeletrischen Materials bleibt bestehen, und zwar solange, bis sie mit der Steuereinheit 13 in ein anderes Ladungsbild abgeändert wird.1 shows a cylindrical printing form 10 with a hollow cylindrical carrier 11 made of electrically conductive material, the surface of which contains a layer 12 made of a ferroelectric material. By one to one Conventional control unit 13 coupled printhead 14 and the support 11 formed as an electrode, the ferroelectric layer 12 is controlled accordingly to generate a charge image 15. This can be done using the methods used to control dielectric layers. The charge image consists of the sum of the negatively polarized, the positively polarized and the neutral halftone dots of the ferroelectric material 12. The charges applied to the surface are firmly bound by the alignment of the ferroelectric domains of the material during polarization and form a double layer of charge and counter-charge that can only be separated by strong external fields or high temperature. If the surface comes into contact with electrically charged toner particles, the charge image is not neutralized or the charge flows away. The polarization of the ferroelectrical material remains until the control unit 13 changes it to a different charge pattern.

Die neutralen Stellen 16 bleiben frei von Farbtonern, während die positiven Punkte negativ geladene Tonerpartikel und die negativen Punkte positiv geladene Partikel anziehen können. Die Möglichkeit von dicht nebeneinander stehenden Polaritäten gegensätzlichen Zeichens auf der Druckform 10 bietet wiederum die Möglichkeit, zwei verschiedene Farben aufzunehmen, indem die eine Farbe positiv und die andere Farbe negativ geladen wird.The neutral areas 16 remain free of color toners, while the positive points can attract negatively charged toner particles and the negative points can attract positively charged particles. The possibility of polarities of opposite characters standing closely next to one another on the printing form 10 in turn offers the possibility of recording two different colors by charging one color positively and the other color negatively.

Fig. 2 zeigt die Zuordnung von zwei Tonerbehältern 17 und 18, wobei der eine Behälter 10 beispielsweise positiv geladenen gelben Toner enthält, während der zweite Behälter 18 mit negativ geladenem roten Toner gefüllt ist. Beim Durchfahren der Behälterbereiche wird mit Hilfe von Bürsten 19 bzw. 20 der Toner an die Oberfläche der ferroelektrischen Schicht 12 herangebracht, wo die Farbpartikel entsprechend dem erzeug­ten Ladungsbild 15 an der Druckform 10 haften bleiben. Schließlich wird, wie in Fig. 3 dargestellt, der aufgenom­mende Farbtoner beim Kontakt mit einem Bedruckstoff 21 auf diesen übertragen und mittels einer Heizquelle 22 darauf fxiert. In einem Druckprozeß werden dabei gleichzeitig zwei Farben aufgetragen, wodurch bei einem Mehrfarbendruck nur halb so viele Druckprozesse für ein Bild erforderlich sind, als mit den konventionellen Methoden.2 shows the assignment of two toner containers 17 and 18, the one container 10 containing, for example, positively charged yellow toner, while the second container 18 is filled with negatively charged red toner. When passing through the container areas, the toner is brought to the surface of the ferroelectric layer 12 with the aid of brushes 19 and 20, where the color particles adhere to the printing form 10 in accordance with the charge image 15 generated. Finally, as shown in FIG. 3, the absorbed color toner is transferred to a printing material 21 when it comes into contact with it and is fixed thereon by means of a heating source 22. Two colors are applied simultaneously in a printing process, which means that in multi-color printing only half as many printing processes are required for an image than with the conventional methods.

Ist nur eine Farbe zu verwenden, dann kann die Polarisation der ferroelektrischen Schicht durchgehend mit Plus und Minus geschehen, d. h. ohne neutrale Stellen 16. Ver­schiedene Grautöne werden entweder durch unterschiedliche Feldstärken erzeugt, womit die anzuziehende Farbe in ihrer Menge variiert werden kann, oder durch autotypische Rasterung mit verschieden großen, aber bis zur Sättigung polarisierten Rasterpunkten. Anstelle eines trockenen Toners können auch in einer Trägerflüssigkeit suspendierte geladene Toner­partikel verwendet werden.If only one color is to be used, the polarization of the ferroelectric layer can be done continuously with plus and minus, ie without neutral positions 16. Different shades of gray are either generated by different field strengths, with which the amount of color to be attracted can be varied, or by autotypical ones Screening with screen spots of different sizes, but polarized to saturation. Instead of a dry toner, charged toner particles suspended in a carrier liquid can also be used.

Im zweiten Ausführungsbeispiel nach Fig. 4 bis 6 ist eine plattenförmige Tiefdruckform dargestellt. Die Tiefdruck­form besteht aus einem Substrat 30 aus einem verschleiß­festen Metall oder aus Keramik. Die Druckform enthält an der Oberfläche rasterartig angeordnete Drucknäpfchen 31, deren Boden jeweils eine ferroelektrische Schicht 32 auf­weist. In ähnlicher Weise wie oben beschrieben, werden die einzelnen ferroelektrischen Schichten 32 innerhalb der Näpfchen 31 bildmäßig angesteuert. Anschließend werden die Näpfchen 31 mit einem flüssigen Toner 33 gefüllt. Wie in Fig. 5 gezeigt, sind die Tonerpartikel darin beispielsweise positiv geladen, während die Oberfläche des ferroelek­rischen Materials 32 mehr oder weniger stark negativ polari­siert ist. Die überschüssige Flüssigkeit 33 wird mittels einer Rakel 34 abgestreift. Gleichzeitig erhält die Rakel 34 eine nagative Ladung, die es ermöglicht, je nach Intensität der Polarität des ferroelektrischen Materials 32, beim Überqueren der Näpfchen 31 gleichzeitig entsprechende Mengen Partikel aus den Näpfchen herauszuziehen. Danach verbleibt in den Näpfchen jeweils eine Menge an Farbpigmenten, die der jeweiligen Feldstärke des zugeordneten ferroelektrischen Materials 32 entsprechen. Die verbliebene Menge der Farb­partikel entspricht schließlich dem gewünschten Grauton. Schließlich wird die auf diese Weise dosierte Farbmenge auf den Bedruckstoff 35 übertragen. Ohne erneute Ansteuerung werden die Näpfchen 31 wieder mit Farbflüssigkeit gefüllt.In the second embodiment according to FIGS. 4 to 6, a plate-shaped gravure form is shown. The rotogravure form consists of a substrate 30 made of a wear-resistant metal or ceramic. The printing form contains pressure cups 31 arranged on the surface in a grid-like manner, the bottom of which each has a ferroelectric layer 32. In a manner similar to that described above, the individual ferroelectric layers 32 within the well 31 are actuated in an imagewise manner. The cups 31 are then filled with a liquid toner 33. As shown in FIG. 5, the toner particles therein are positively charged, for example, while the surface of the ferroelectric material 32 is more or less negatively polarized. The excess liquid 33 is wiped off by means of a doctor blade 34. At the same time, the doctor blade 34 receives a nagative charge, which makes it possible, depending on the intensity of the polarity of the ferroelectric material 32, to simultaneously pull corresponding amounts of particles out of the cells when crossing the cells 31. Thereafter, a quantity of color pigments remains in the cells, which correspond to the respective field strength of the assigned ferroelectric material 32. The remaining amount of color particles finally corresponds to the desired shade of gray. Finally, the amount of ink metered in this way is transferred to the printing material 35. Without renewed activation, the wells 31 are filled with colored liquid again.

Die erfindungsgemäße Druckform eignet sich sowohl für Druckmaschinen als auch für andere Vervielfältigungsgeräte, wie Kopiergeräte.The printing form according to the invention is suitable both for printing presses and for other duplicating devices, such as copiers.

Claims (4)

1. Druckform zum Vervielfältigen einer Bildvorlage, mit der elektrisch geladene Farbelemente unter Nutzung eines elektrostatischen Feldes auf einen Bedruckstoff übertragbar sind,
dadurch gekennzeichnet,
daß die die Farbelemente übertragende Schicht (12) der Druckform (10) aus einem ferroelektrischen Material besteht.1. printing form for duplicating an image with which electrically charged color elements can be transferred to a printing material using an electrostatic field,
characterized,
that the layer (12) of the printing form (10) which transmits the color elements consists of a ferroelectric material. 2. Druckform nach Anspruch 1, dadurch gekennzeichnet, daß die Druckform (10) aus einem Träger (11) besteht, dessen mindestens eine Oberfläche (12) mit einem ferroelektrischen Material beschichtet ist.2. Printing form according to claim 1, characterized in that the printing form (10) consists of a carrier (11) whose at least one surface (12) is coated with a ferroelectric material. 3. Druckform nach Anspruch 1, dadurch gekennzeichnet, daß die Druckform ein Substrat (30) aus einem verschleiß­festen Material besteht, das einseitig Tiefdrucknäpf­chen enthält, und daß der Boden der Näpfchen aus ferro­elektrischem Material (32) besteht.3. Printing form according to claim 1, characterized in that the printing form comprises a substrate (30) made of a wear-resistant material which contains gravure cells on one side, and that the bottom of the cells consists of ferroelectric material (32). 4. Druckform nach Anspruch 3, dadurch gekennzeichnet, daß der Druckform eine Ansteuereinheit (13′, 14′) zugeordnet ist, mit der die ferroelektrischen Schichten (32) der Näpfchen (31) jeweils unterschie­lich stark polarisiert werden können.4. Printing form according to claim 3, characterized in that the printing form is assigned a control unit (13 ', 14') with which the ferroelectric layers (32) of the wells (31) can each be polarized to a different degree.
EP89118900A 1988-10-14 1989-10-11 Printing forme Expired - Lifetime EP0363932B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3835091 1988-10-14
DE3835091A DE3835091A1 (en) 1988-10-14 1988-10-14 PRINTING FORM

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EP0363932A2 true EP0363932A2 (en) 1990-04-18
EP0363932A3 EP0363932A3 (en) 1990-11-22
EP0363932B1 EP0363932B1 (en) 1996-12-11

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0458230A2 (en) * 1990-05-24 1991-11-27 MAN Roland Druckmaschinen AG Method and device for toning a printing forme of ferroelectric material
WO1991018743A1 (en) * 1990-05-31 1991-12-12 Ludwig Bartl Process and device for printing variable information
EP1016519A2 (en) * 1998-12-30 2000-07-05 Xerox Corporation Printing plate with reversible electrical charge-controlled wettability
EP1260360A3 (en) * 2001-05-23 2004-01-07 Heidelberger Druckmaschinen Aktiengesellschaft Printing process and device
EP1990693A1 (en) * 2006-03-02 2008-11-12 Kabushi Kaisha Toshiba Cleaning apparatus, cleaning method, pattern forming apparatus and pattern forming method
EP1995060A1 (en) * 2007-05-22 2008-11-26 Ernst-Rudolf Dr. Weidlich Method for influencing the colour content and/or colour dispensing ability of printing plates and printing device
EP3900934A1 (en) * 2020-04-21 2021-10-27 Flooring Technologies Ltd. Device for generating a print on a printing material and method for producing a plurality of cavities on a printing form with a magnetic grid

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DE4140996C2 (en) * 1991-12-12 2001-10-11 Fogra Forschungsgesellschaft D Electrophotographic printing process, printing form and process for producing this printing form
DE4328037A1 (en) * 1993-08-20 1995-03-02 Roland Man Druckmasch Printing process with ferroelectrics
DE19521187C2 (en) * 1995-06-10 1997-08-07 Fraunhofer Ges Forschung Use of a ferroelectric ceramic material for information storage in electrostatic printing processes
DE19601586C1 (en) * 1996-01-18 1997-07-10 Roland Man Druckmasch Ferroelectric printing form production method
DE10052853A1 (en) * 2000-10-25 2002-05-08 Anton Rodi Relief pattern of pixel elements are produced on the surface of a polycrystalline ceramic

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Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0458230A2 (en) * 1990-05-24 1991-11-27 MAN Roland Druckmaschinen AG Method and device for toning a printing forme of ferroelectric material
EP0458230A3 (en) * 1990-05-24 1993-08-25 Man Roland Druckmaschinen Ag Method and device for toning a ferroelectric material with a liquid film
WO1991018743A1 (en) * 1990-05-31 1991-12-12 Ludwig Bartl Process and device for printing variable information
EP1016519A2 (en) * 1998-12-30 2000-07-05 Xerox Corporation Printing plate with reversible electrical charge-controlled wettability
EP1016519A3 (en) * 1998-12-30 2001-03-14 Xerox Corporation Printing plate with reversible electrical charge-controlled wettability
EP1260360A3 (en) * 2001-05-23 2004-01-07 Heidelberger Druckmaschinen Aktiengesellschaft Printing process and device
US6935235B2 (en) 2001-05-23 2005-08-30 Heidelberger Druckmaschinen Ag Printing method and device
EP1990693A1 (en) * 2006-03-02 2008-11-12 Kabushi Kaisha Toshiba Cleaning apparatus, cleaning method, pattern forming apparatus and pattern forming method
EP1990693A4 (en) * 2006-03-02 2010-03-17 Toshiba Kk Cleaning apparatus, cleaning method, pattern forming apparatus and pattern forming method
EP1995060A1 (en) * 2007-05-22 2008-11-26 Ernst-Rudolf Dr. Weidlich Method for influencing the colour content and/or colour dispensing ability of printing plates and printing device
EP3900934A1 (en) * 2020-04-21 2021-10-27 Flooring Technologies Ltd. Device for generating a print on a printing material and method for producing a plurality of cavities on a printing form with a magnetic grid

Also Published As

Publication number Publication date
EP0363932A3 (en) 1990-11-22
DE58909754D1 (en) 1997-01-23
DE3835091A1 (en) 1990-04-19
CA2000343C (en) 1996-10-29
CA2000343A1 (en) 1990-04-14
JPH02217871A (en) 1990-08-30
EP0363932B1 (en) 1996-12-11
JP2708066B2 (en) 1998-02-04
DE3835091C2 (en) 1991-06-06

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