EP0363932B1 - Printing forme - Google Patents

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Publication number
EP0363932B1
EP0363932B1 EP89118900A EP89118900A EP0363932B1 EP 0363932 B1 EP0363932 B1 EP 0363932B1 EP 89118900 A EP89118900 A EP 89118900A EP 89118900 A EP89118900 A EP 89118900A EP 0363932 B1 EP0363932 B1 EP 0363932B1
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EP
European Patent Office
Prior art keywords
printing
ferro
printing forme
toner
electric material
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EP89118900A
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German (de)
French (fr)
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EP0363932A3 (en
EP0363932A2 (en
Inventor
Hartmut Fuhrmann
Alfred Dr. Hirt
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Manroland AG
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MAN Roland Druckmaschinen AG
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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 method according to claim 1.
  • a method is already known from JP 63-220177 in which a ferroelectric printing form is used for printing.
  • the printing form has a flat surface, which is coated with a dry, powdery toner for printing.
  • the printing form is illustrated before the printing process. For this purpose, it is polarized positively and negatively according to the image to be printed. In a subsequent development step, positively charged areas of the printing form attract negatively charged toner particles. These are then printed on paper.
  • pyroelectric materials such as e.g. PLZT
  • a pyroelectric film is imaged by applying an electric field to it while at the same time maintaining it at a temperature above a dipole orientation temperature specific to the material. After the film has cooled to ambient temperature, it is immersed in a warm toner bath, whereby it is reheated so that it then has electrical charges on its surface which are capable of attracting charged toner particles and depositing them on the surface of the pyroelectric film . Finally, the toner particles are transferred to the paper.
  • the pyroelectric effect is used both in the production of the latent image and in its development, i. H. that a pyroelectric material is permanently polarized when heated and with the application of an electric field and that it is introduced for imaging in a warm or cold toner bath which contains charged toner particles.
  • a printing form with a dielectric or photoconductive layer is known from DE 19 57 403 B2. Electrodes are assigned to this layer for imagewise charging. 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.e. the charge image can be generated again.
  • GB 1 311 673 discloses a method for controlling toning or coloring in printing or copying processes, in which a printing form is used which has a multiplicity of small cups on its surface which receive the printing ink. These cells are similar to gravure cells.
  • the toner particles in the cells are electrically charged in accordance with the electrical field generated by a first electrode in the vicinity of the surface of the forme cylinder and, depending on the state of charge, are moved to the surface or to the bottom of the cells.
  • the electrically conductive surface of the printing cylinder which presses a printing material web against the forme cylinder, serves as the second electrode.
  • the charged particles are transferred to the printing material web or remain in the cells.
  • the loading process must be repeated after each printing or copying step.
  • the invention has for its object to provide a new printing method, which is characterized by the simplicity in its execution as well as by high print quality.
  • the present invention is a printing process 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 using two colors with differently charged particles, ie that 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 for a toner contained in a fountain solution as a carrier.
  • Another advantage of the invention results from the fact that the method according to the invention is also suitable for gravure printing.
  • the printing form to be used can 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 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 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 electrical 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 results in control of the amount of color or toner in the well.
  • the image-filled cup is then transferred to the printing material in accordance with conventional gravure printing technology.
  • 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, with which the printing form surface is controlled in a matrix-like manner in accordance with an image template, each pixel being polarized to a greater or lesser extent in accordance with the associated gray tone.
  • the charge image thus generated can be combined with a color application brush for a toner, with more or less color being applied to the printing form surface at points.
  • a toner (liquid toner) suspended in a carrier liquid is used.
  • 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 orientation of the ferroelectric domains 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 ferroelectric 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 side by side on the printing form 10 in turn offers the possibility of recording two different colors by one color being charged positively and the other color negatively.
  • FIG. 2 shows the assignment of two toner containers 17 and 18, the one container 17 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 rotogravure form consists of a substrate 30 made of a wear-resistant metal or ceramic.
  • the printing form contains pressure cups 31 arranged in a grid-like manner on the surface, the bottom of each of which has a ferroelectric layer 32.
  • the individual ferroelectric layers 32 within the well 31 are controlled imagewise.
  • 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 negative 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.

Description

Die Erfindung bezieht sich auf ein Verfahren nach Anspruch 1.The invention relates to a method according to claim 1.

Aus der JP 63-220177 ist bereits ein Verfahren bekannt, bei dem eine ferroelektrische Druckform zum Drucken verwendet wird. Die Druckform hat eine ebene Oberfläche, die zum Drucken mit einem trockenen, pulverförmigen Toner betonert wird. Vor dem Druckprozeß wird die Druckform bebildert. Hierzu wird sie entsprechend dem zu druckenden Bild bildmäßig positiv und negativ polarisiert. In einem darauffolgenden Entwicklungsschritt ziehen positiv geladene Flächenanteile der Druckform negativ geladene Tonerpartikel an. Diese werden dann auf Papier gedruckt.A method is already known from JP 63-220177 in which a ferroelectric printing form is used for printing. The printing form has a flat surface, which is coated with a dry, powdery toner for printing. The printing form is illustrated before the printing process. For this purpose, it is polarized positively and negatively according to the image to be printed. In a subsequent development step, positively charged areas of the printing form attract negatively charged toner particles. These are then printed on paper.

Aus der US 3 899 969 ist ein Verfahren bekannt, bei dem mit pyroelektrischen Materialien, wie z.B. PLZT, gedruckt wird. Ein pyroelektrischer Film wird dadurch bebildert, daß an ihn ein elektrisches Feld angelegt wird, wahrend er gleichzeitig bei einer Temperatur gehalten wird, die oberhalb einer für das Material spezifischen Dipol-Orientierungstemperatur gehalten wird. Nachdem der Film auf Umgebungstemperatur abgekühlt ist, wird er in ein warmes Tonerbad getaucht, wodurch er erneut erwärmt wird, so daß er dann auf seiner Oberfläche elektrische Ladungen aufweist, die in der Lage sind, geladene Tonerpartikel anzuziehen und auf der Oberfläche des pyroelektrischen Films abzulagern. Abschließend werden die Tonerpartikel auf das Papier übertragen. Bei dem bekannten Verfahren wird der pyroelektrische Effekt sowohl bei der Herstellung des latenten Bildes als auch bei dessen Entwicklung ausgenutzt, d. h. daß ein pyroelektrisches Material bei Erwärmung und unter Anlegung eines elektrischen Feldes permanent gepolt wird und daß es zur Bebilderung in ein warmes oder kaltes Tonerbad eingebracht wird, das geladene Tonerpartikel enthält.From US 3 899 969 a method is known in which pyroelectric materials such as e.g. PLZT, is printed. A pyroelectric film is imaged by applying an electric field to it while at the same time maintaining it at a temperature above a dipole orientation temperature specific to the material. After the film has cooled to ambient temperature, it is immersed in a warm toner bath, whereby it is reheated so that it then has electrical charges on its surface which are capable of attracting charged toner particles and depositing them on the surface of the pyroelectric film . Finally, the toner particles are transferred to the paper. In the known method, the pyroelectric effect is used both in the production of the latent image and in its development, i. H. that a pyroelectric material is permanently polarized when heated and with the application of an electric field and that it is introduced for imaging in a warm or cold toner bath which contains charged toner particles.

Aus der DE 25 30 290 A1 sind bereits ein Verfahren und eine Vorrichtung zum Drucken und Kopieren bekannt, bei denen Ferroelektrika verwendet werden. Einem Ferroelektrikum wird in einem ersten Schritt bildmäßig ein äußeres elektrisches Feld oder eine mechanische Kraft aufgeprägt, wodurch auf der Oberfläche des Materials ein bildmäßiges ferroelektrisches Polarisationsmuster erzeugt wird. In einem zweiten Schritt wird in dem ferroelektrischen Material eine Veränderung eines äußeren elektrischen Feldes, einer mechanischen Kraft oder einer Wärme zur vorübergehenden Änderung der Stärke der ferroelektrischen Polarisation erzeugt, um so auf der Materialoberfläche des Ferroelektrikums ein dem Muster der ferroelektrischen Polarisation entsprechendes bildmäßiges Ladungsmuster zu erzeugen.DE 25 30 290 A1 already discloses a method and a device for printing and copying in which ferroelectrics are used. In a first step, an external electric field or a mechanical force is impressively impressed on a ferroelectric, as a result of which an imagewise ferroelectric polarization pattern is generated on the surface of the material. In a second step, a change in an external electric field, a mechanical force or a heat for temporarily changing the strength of the ferroelectric polarization is generated in the ferroelectric material, so as to produce an image-like charge pattern corresponding to the pattern of the ferroelectric polarization on the material surface of the ferroelectric .

Eine Druckform mit einer dielektrischen oder photoleitfähigen Schicht ist aus der DE 19 57 403 B2 bekannt. Dieser Schicht sind zur bildmäßigen Aufladung Elektroden zugeordnet. 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 with a dielectric or photoconductive layer is known from DE 19 57 403 B2. Electrodes are assigned to this layer for imagewise charging. 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.e. the charge image can be generated again.

Darüber hinaus ist aus der GB 1 311 673 ein Verfahren zum Steuern des Tonens oder der Farbgebung bei Druck- oder Kopiervorgängen bekannt, bei dem eine Druckform verwendet wird, die eine Vielzahl von kleinen Näpfchen auf ihrer Oberfläche aufweist, die die Druckfarbe aufnehmen. Diese Näpfchen ähneln Tiefdrucknäpfchen. Während des Druckprozesses werden die Tonerpartikel in den Näpfchen entsprechend dem von einer ersten Elektrode in der Nähe der Oberfläche des Formzylinders erzeugten elektrischen Feld elektrisch geladen und werden je nach Ladungszustand zur Oberfläche oder zum Boden der Näpfchen bewegt. Als zweite Elektrode dient die elektrisch leitende Oberfläche des Druckzylinders, der eine Bedruckstoffbahn gegen den Formzylinder drückt. Entsprechend ihrem Ladungszustand und der Ladung der Oberfläche des Druckzylinders werden die geladenen Partikel auf die Bedruckstoffbahn übertragen oder verbleiben in den Näpfchen. Nach jedem Druck- oder Kopierschritt muß der Ladungsvorgang wiederholt weden.In addition, GB 1 311 673 discloses a method for controlling toning or coloring in printing or copying processes, in which a printing form is used which has a multiplicity of small cups on its surface which receive the printing ink. These cells are similar to gravure cells. During the printing process, the toner particles in the cells are electrically charged in accordance with the electrical field generated by a first electrode in the vicinity of the surface of the forme cylinder and, depending on the state of charge, are moved to the surface or to the bottom of the cells. The electrically conductive surface of the printing cylinder, which presses a printing material web against the forme cylinder, serves as the second electrode. Depending on their charge state and the charge on the surface of the printing cylinder, the charged particles are transferred to the printing material web or remain in the cells. The loading process must be repeated after each printing or copying step.

Den aus der DE 19 57 403 B2 und der GB 1 311 673 bekannten elektrostatischen Verfahren ist somit gemeinsam, daß die elektrischen Ladungen nach jeder Übertragung der Farbelemente auf den Bedruckstoff wieder verschwinden und erneut aufgebracht werden müssen.The electrostatic processes known from DE 19 57 403 B2 and GB 1 311 673 therefore have in common that the electrical charges disappear again after each transfer of the color elements to the printing material and must be reapplied.

Der Erfindung liegt die Aufgabe zugrunde, ein neues Druckverfahren zu schaffen, das sich gleichermaßen durch die Einfachheit in seiner Ausführung wie durch hohe Druckqualität auszeichnet.The invention has for its object to provide a new printing method, which is characterized by the simplicity in its execution as well as by high print quality.

Die Aufgabe wird durch die Merkmale des Patentanspruchs 1 gelöst.The object is achieved by the features of patent 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 print run 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 delivers it to a printing material, the charge image being maintained.

Aus der EP 0 262 475 A2 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, daß unterschiedlich polarisierte Stellen des ferroelektrischen Materials unterschiedliche Affinitäten für Öl und Wasser haben.Although the introduction of ferroelectric materials into printing machines has become known from EP 0 262 475 A2, the electrical field is not used in the application described therein. The known system rather refers to conventional offset printing with oil colors and dampening solutions. In this known method the property is used 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 process 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 using two colors with differently charged particles, ie that 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 für einen in einem Feuchtmittel als Träger enthaltenen Toner. Ein weiterer Vorteil der Erfindung ergibt sich dadurch, daß das erfindungsgemäße Verfahren ebenfalls für den Tiefdruck geeignet ist. Hierzu kann die einzusetzende Druckform 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 for a toner contained in a fountain solution as a carrier. Another advantage of the invention results from the fact that the method according to the invention is also suitable for gravure printing. For this purpose, the printing form to be used can 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 mit einer Ansteuereinrichtung verbunden, mit der die ferroelektrischen Böden der Näpfchen entsprechend dem Grauton des zugehörigen Bildpunktes unterschiedlich stark polarisiert werden können.Such a printing form is 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.

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.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 electrical 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 results in control of the amount of color or toner in the well. The color The image-filled cup is then transferred to the printing material in accordance with conventional gravure printing technology.

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 stärker oder weniger stark polarisiert wird. Das so erzeugte Ladungsbild kann mit einer Farbauftragbürste für einen Toner in Verbindung gesetzt werden, wobei punktweise mehr oder weniger Farbe auf die Druckformoberfläche aufgetragen wird. Bein Kontakt der mit Farbton beladenen Oberfläche der Druckform mit einem Bedruckstoff und einer Gegenelektrode wird die Farbe auf den Bedruckstoff übertragen. Es wird ein in einer Trägerflüssigkeit suspendierter Toner (Flüssigtoner) verwendet.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, with which the printing form surface is controlled in a matrix-like manner in accordance with an image template, each pixel being polarized to a greater or lesser extent in accordance with the associated gray tone. The charge image thus generated can be combined with a color application brush for a toner, with more or less color being applied to the printing form surface at points. When the surface of the printing plate loaded with color tone comes into contact with a printing material and a counterelectrode, the color is transferred to the printing material. A toner (liquid toner) suspended in a carrier liquid is used.

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 method sequence according to a first embodiment and
4 to 6
a consequence 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 dar Summe der negativ polarisierten, der positiv polarisierten und der neutralen Rasterpunkte des ferroelektrischan Materials 12. Die auf die Oberfläche aufgebrachten Ladungen sind durch die Ausrichtung der ferroelektrischen Domänen das 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 elektisch geladenen Tonerpartikeln kommt, findet keine Neutralisierung das Ladungsbildes bzw. ein Abfließen der Ladung statt. Die Polarisierung des ferroelektrischen 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 designed 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 orientation of the ferroelectric domains 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 ferroelectric 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 side by side on the printing form 10 in turn offers the possibility of recording two different colors by one color being charged positively and the other color negatively.

Fig. 2 zeigt die Zuordnung von zwei Tonerbehältern 17 und 18, wobei der eine Behälter 17 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 17 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 werden verschiedene Grautöne durch unterschiedliche Feldstärken erzeugt, womit die anzuziehende Farbe in ihrer Menge variiert werden kann. Es werden in einer Trägerflüssigkeit suspendierte geladene Tonerpartikel verwendet.If only one color is to be used, then different shades of gray are generated by different field strengths, with which the amount of the color to be drawn can be varied. Charged toner particles suspended in a carrier liquid are 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 negative 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 exemplary 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 in a grid-like manner on the surface, the bottom of each of which has a ferroelectric layer 32. In a manner similar to that described above, the individual ferroelectric layers 32 within the well 31 are controlled imagewise. 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 negative 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. Process for the reproduction of an image original by means of a printing forme (10), wherein
    - the printing forme contains a ferro-electric material (12, 32);
    - the ferro-electric material is polarised image-wise and the polarisation is maintained until said polarisation is altered by a control unit (13, 13', 14, 14');
    - electrically-charged toner particles of a toner liquid are brought into contact with the ferro-electric material, the toner particles being deposited at differently polarised points in the ferro-electric material; and
    - a print material (21, 35) is printed in a continuous printing process by means of revolutions of a cylindrical carrier (11) provided with the printing forme.
  2. Process according to claim 1, characterised in that the surface of the printing forme (10) contains a layer of the ferro-electric material (12).
  3. Process according to claim 1, characterised in that the printing forme comprises a substrate (30) which is made of a wear-resistant mateerial and is provided on one side with gravure cells (31), the bottom of which contain the ferro-electric material (32).
  4. Process according to one of the preceding claims, characterised in that the control unit (13, 13', 14, 14') polarises the ferro-electric layer to different degrees.
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 EP0363932A2 (en) 1990-04-18
EP0363932A3 EP0363932A3 (en) 1990-11-22
EP0363932B1 true EP0363932B1 (en) 1996-12-11

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JP (1) JP2708066B2 (en)
CA (1) CA2000343C (en)
DE (2) DE3835091A1 (en)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5213931A (en) * 1990-05-24 1993-05-25 Man Roland Druckmaschinen Ag Method and means for hydraulic meniscus toning of ferro electric materials
AU7970591A (en) * 1990-05-31 1991-12-31 Ludwig Bartl Process and device for printing variable information
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
US6146798A (en) * 1998-12-30 2000-11-14 Xerox Corporation Printing plate with reversible charge-controlled wetting
DE10052853A1 (en) * 2000-10-25 2002-05-08 Anton Rodi Relief pattern of pixel elements are produced on the surface of a polycrystalline ceramic
DE10125545A1 (en) * 2001-05-23 2002-11-28 Heidelberger Druckmasch Ag Printing method and device
WO2007099848A1 (en) * 2006-03-02 2007-09-07 Kabushiki 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
EP3900934B1 (en) * 2020-04-21 2022-05-18 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 raster

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1127830A (en) * 1965-10-24 1968-09-18 Continental Can Co Apparatus for intaglio electrostatic printing
CA1001704A (en) * 1968-11-15 1976-12-14 Thomas D. Kittredge Apparatus for aperture controlled electrostatic image reproduction or constitution
GB1311673A (en) * 1969-03-12 1973-03-28 Masson Scott Thrissell Eng Ltd Methods and apparatus for electrostatic printing or copying
US3765330A (en) * 1971-01-06 1973-10-16 Xerox Corp Xeroprinting employing letterpress surface covered with a layer of resistive material
US3801315A (en) * 1971-12-27 1974-04-02 Xerox Corp Gravure imaging system
US3951533A (en) * 1974-09-20 1976-04-20 Xerox Corporation Color image reproduction system
DE3633758A1 (en) * 1986-10-03 1988-04-07 Man Technologie Gmbh PRINTING MACHINE
GB2198085B (en) * 1986-11-29 1991-02-13 Stc Plc Printing apparatus and process
JP2581059B2 (en) * 1987-03-09 1997-02-12 ミノルタ株式会社 Latent image writing method and image forming method using the same
JPS63220259A (en) * 1987-03-10 1988-09-13 Ricoh Co Ltd Image forming method

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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
JP2708066B2 (en) 1998-02-04
DE3835091C2 (en) 1991-06-06
EP0363932A2 (en) 1990-04-18

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