EP0746470B1 - Thermotransfer printing device for transferring an image to a substrate - Google Patents

Thermotransfer printing device for transferring an image to a substrate Download PDF

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Publication number
EP0746470B1
EP0746470B1 EP95901344A EP95901344A EP0746470B1 EP 0746470 B1 EP0746470 B1 EP 0746470B1 EP 95901344 A EP95901344 A EP 95901344A EP 95901344 A EP95901344 A EP 95901344A EP 0746470 B1 EP0746470 B1 EP 0746470B1
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EP
European Patent Office
Prior art keywords
fabric
fabric tape
transfer printing
thermal transfer
printing device
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EP95901344A
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German (de)
French (fr)
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EP0746470A1 (en
Inventor
Manfred Wiedemer
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Canon Production Printing Germany GmbH and Co KG
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Oce Printing Systems GmbH and Co KG
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Publication of EP0746470A1 publication Critical patent/EP0746470A1/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/0057—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material where an intermediate transfer member receives the ink before transferring it on the printing material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material

Definitions

  • the invention relates to a thermal transfer printing device for transferring a print image to a recording medium in a printing or copying machine.
  • the heating elements are activated by a control unit in accordance with the print image to be reproduced. Rapid heating of the ink causes bubbles to form in the openings of the ink film, as a result of which the ink is immediately expelled from the openings in the direction of the recording medium.
  • the printing ink In the known thermal transfer printing device, however, considerable demands are placed on the printing ink.
  • the printing ink must be thermally stable up to approximately 400 ° C.
  • the load on the surface of the recording medium also increases in accordance with the temperature of the printing ink. It is therefore only possible to use record carriers that meet these high requirements. Since the heating process is limited to the relatively small area of the print head, the achievable printing speed is also limited accordingly.
  • thermal transfer printing device with several thermal printheads is known. Each thermal print head is used to transfer an ink to a recording medium. Each thermal print head is assigned a cassette which has an ink reservoir in which the openings of an ink film are filled with ink. The ink film is passed over the thermal print head, where the ink is heated and transferred to a recording medium by bubbling. With multi-color printing, several transfer points are required depending on the number of colors.
  • the present invention has for its object to show a thermal transfer printing device for transferring a print image to a record carrier in a printing or copying machine, which allows the use of conventional, large thermal stresses insufficient inks, ensures a low load on the record carrier and allows a high printing speed .
  • the thermal transfer printing device makes it possible to use conventional dyes in thermal transfer printing.
  • the heat effect of the heating device provided at the transfer printing point is limited to the liquid located in the first fabric band. This liquid is evaporated and thereby partially drives the printing ink out of the second fabric tape in the direction of the recording medium.
  • the ink striking the recording medium is only slightly warmed, which means that the recording medium is only slightly thermally stressed. Since the print image is generated by evaporation of the liquid in the first fabric belt at two different locations and thus the total energy for generating the print image is given off at two spaced-apart locations, the thermal load on the heating device located at the transfer location is comparatively low.
  • the division of the printing energy can also be used to increase the printing speed.
  • the fabric tapes have the property of absorbing liquid or printing ink and partially releasing it again.
  • the term fabric tape therefore also refers to tapes with a non-regular structure, such as a flow, and all other materials that have the functionality mentioned.
  • the thermal transfer printing device contains a dyeing station in which an ink-carrying roller can be brought into contact by selectively moving a counter-pressure roller toward the ink-carrying roller with the second fabric tape located between the roller and the counter-pressure roller. This ensures that printing ink is only applied at the points on the second fabric band where this is necessary. For example, only the locations of a second web of fabric in endless form need to be re-applied with printing ink from which ink had been taken in a previous transfer printing operation.
  • At least two ink-bearing rollers are arranged one behind the other in the running direction of the second fabric belt.
  • different colors can be applied to the second fabric tape in sections at the desired locations. Multi-color printing is therefore possible with only one color-bearing fabric tape. Sections which are not wetted with printing ink are preferably left free between the individual sections of different coloring on the second fabric band. In the event of a print pause, these color-free areas are then positioned over the heating device of the transfer printing point.
  • the print image transfer point contains a thermal comb with heating elements which can be activated independently of one another, a heating element corresponding to a pixel.
  • the liquid from the first fabric band can be partially evaporated according to the available pressure information.
  • the dot size and color density, which is to be achieved in the subsequent transfer printing in the transfer printing station, can be determined both by varying the heating energy on the heating device of the transfer printing station and by varying the heating energy of the heating elements of the thermal comb.
  • Water is suitable as the non-toxic liquid with which the first fabric band can be wetted. When water evaporates, there are no toxic vapors that could affect the ambient air of the printer or the functional elements inside the printer. The water vapor can be removed by a suction device. However, other non-toxic liquids that have a corresponding evaporation point and do not cause any harmful environmental influences are also suitable.
  • the figure shows a thermal transfer printing device with a first and a second fabric ribbon.
  • the first fabric belt 1 is designed as an endless belt. It is clamped between two rollers 10, 16, the axes of which run parallel. One of the rollers 10 is assigned to the transfer printing point 12, and the other roller 16 is assigned to a dampening unit 2.
  • the first fabric tape 1 is at least as wide as the widest record carrier 9 to be processed. The length of the first fabric tape 1 is selected so that the distance between the two rollers 10, 16, on which the first fabric tape 1 is stretched, is so great that a print image transfer point 3 can be arranged in this distance range.
  • the print image transfer point 3 contains a heating device 13 with which, according to the available print information, a non-toxic liquid 19 contained in the first fabric band 1 can be partially evaporated.
  • a thermal comb 13 serves as the heating device 13.
  • the thermal comb 13 contains a plurality of heating elements, each of which can be assigned a pixel of the printing information.
  • a laser or an infrared light source, which can be controlled accordingly, could also be used as the heating device 13.
  • the thermal comb 13 extends over the entire width of the first fabric band 1.
  • the first fabric band 1 is guided directly over the thermal comb 13.
  • a suction device 18 is provided which sucks off the vaporized liquid 19.
  • the liquid 19, for example water, can be condensed in a condensation device (not shown) arranged downstream of the suction device 18 and can be fed back to the dampening unit 2.
  • the second fabric belt 4 like the first fabric belt 1, is designed as an endless belt.
  • the second fabric tape 4 consists of polyester or metallized polyester with a fabric thickness of ⁇ 100 microns.
  • the second fabric tape 4 has at least a width which corresponds to the width of the widest record carrier 9 to be printed.
  • the second fabric belt 4 is guided over three rollers 10, 20, 21, the axes of which are parallel to one another. In the area of the heating roller 10, the first fabric belt 1 is located between the heating roller 10 and the second fabric belt 4.
  • the direction of movement and speed of the belts 1, 4 are identical.
  • the second fabric tape 4 passes through a dyeing station 5.
  • four different printing inks 11 are optionally applied to the second fabric tape 4.
  • the inking station 5 can be constructed in a modular manner, as a result of which any number of printing inks 11 can be applied to the second fabric tape 4.
  • the ink is applied in each case by an ink-bearing roller 7, which is arranged on one side of the second fabric belt 4.
  • the ink-bearing roller 7 is assigned a counter-pressure roller 6. This counter pressure roller 6 is movable perpendicular to the surface of the second fabric belt 4. If ink is to be applied, the counter-pressure roller 6 is moved to the ink-bearing roller 7.
  • the counter-pressure roller 6 hits the second fabric belt 4 and moves it to the ink-bearing roller 7. This brings the second fabric belt 4 and the ink-bearing roller 7 into contact, as a result of which ink 11 is transferred from the ink-bearing roller 7 to the second fabric belt 4 .
  • the ink-bearing roller 7 is always wetted with printing ink 11 by a rolling movement on a supply roller 22, which is immersed in an ink supply 11.

Abstract

The invention calls for an image to be produced, at an image-transfer station (3), by partial evaporation of liquid (19) embedded in a first continuous strip of fabric (1) capable of being wetted by the liquid (19). At a subsequent transfer station (12), the first continuous strip of fabric passes between a heater (10) and a second continuous strip of fabric (4). Embedded in the second strip of fabric (4) is printing ink (11). The ink (11) is forced out of the second strip of fabric (4) and on to a substrate (9) by the liquid (19) remaining in the first strip of fabric, this liquid representing the image to be printed and being evaporated at the transfer station.

Description

Die Erfindung betrifft eine Thermotransferdruckvorrichtung zur Übertragung eines Druckbildes auf einen Aufzeichnungsträger in einem Druck- oder Kopiergerät.The invention relates to a thermal transfer printing device for transferring a print image to a recording medium in a printing or copying machine.

Aus US-A-4 731 619 ist ein Thermodruckkopf einer Thermotransferdruckvorrichtung bekannt. Der Thermodruckkopf ist an einer Umdruckstelle angeordnet. An dieser Umdruckstelle wird ein Druckbild auf einen Aufzeichnungsträger übertragen. Zwischen dem Thermodruckkopf und dem Aufzeichnungsträger wird in einer Aufzeichnungsträgertransportrichtung ein Druckfarbfilm transportiert. Dieser Druckfarbfilm weist eine Mehrzahl kleiner Öffnungen auf, in denen Druckfarbe enthalten ist. Diese Druckfarbe wird in einer Einfärbestation in die Öffnungen des Druckfarbfilms eingebracht. An der Umdruckstelle gleitet der Druckfarbfilm über den Thermodruckkopf und wird dabei vorgewärmt. Der Thermodruckkopf weist eine Mehrzahl von einzeln ansteuerbaren Heizelementen auf, die dem schnellen Erwärmen der Druckfarbe in den Öffnungen des Druckfarbfilms dienen. Entsprechend dem wiederzugebenden Druckbild werden die Heizelemente von einer Steuereinheit aktiviert. Durch schnelles Erwärmen der Druckfarbe wird eine Blasenbildung in den Öffnungen des Druckfarbfilms hervorgerufen, wodurch die Druckfarbe augenblicklich in Richtung des Aufzeichnungsträgers aus den Öffnungen ausgetrieben wird.From US-A-4 731 619 a thermal print head of a thermal transfer printing device is known. The thermal print head is arranged at a transfer printing point. At this transfer location, a print image is transferred to a recording medium. An ink film is transported in a recording medium transport direction between the thermal print head and the recording medium. This ink film has a plurality of small openings in which ink is contained. This printing ink is introduced into the openings of the printing ink film in a coloring station. At the transfer location, the ink film slides over the thermal print head and is preheated. The thermal print head has a plurality of individually controllable heating elements which are used for the rapid heating of the printing ink in the openings of the printing ink film. The heating elements are activated by a control unit in accordance with the print image to be reproduced. Rapid heating of the ink causes bubbles to form in the openings of the ink film, as a result of which the ink is immediately expelled from the openings in the direction of the recording medium.

Mit der bekannten Methode sind hochviskose Druckfarben mit hohem Pigmentanteil auf den Aufzeichnungsträger übertragbar. Auch Halbtöne können damit gedruckt werden, wodurch auch Farbbilder in Fotoqualität erzeugbar sind.With the known method, highly viscous printing inks with a high pigment content can be transferred to the recording medium. Halftones can also be printed with it, which means that color images can also be produced in photo quality.

Bei der bekannten Thermotransferdruckvorrichtung werden jedoch erhebliche Anforderungen an die Druckfarbe gestellt. So muß die Druckfarbe thermisch bis etwa 400°C stabil sein. Entsprechend der Temperatur der Druckfarbe steigt auch die Belastung der Oberfläche des Aufzeichnungsträgers. Es können deshalb nur Aufzeichnungsträger verwendet werden, die diesen hohen Anforderungen gerecht werden. Da der Erwärmungsvorgang auf den relativ kleinen Bereich des Druckkopfs beschränkt ist, ist auch die erreichbare Druckgeschwindigkeit entsprechend begrenzt.In the known thermal transfer printing device, however, considerable demands are placed on the printing ink. The printing ink must be thermally stable up to approximately 400 ° C. The load on the surface of the recording medium also increases in accordance with the temperature of the printing ink. It is therefore only possible to use record carriers that meet these high requirements. Since the heating process is limited to the relatively small area of the print head, the achievable printing speed is also limited accordingly.

Aus EP-A-0 202 370 ist eine Thermotransferdruckvorrichtung mit mehreren Thermodruckköpfen bekannt. Jeder Thermodruckkopf dient zur Übertragung einer Druckfarbe auf einen Aufzeichnungsträger. Jedem Thermodruckkopf ist eine Kassette zugeordnet, die ein Druckfarbenreservoir aufweist, in dem die Öffnungen eines Druckfarbfilms mit Druckfarbe gefüllt werden. Der Druckfarbfilm wird über den Thermodruckkopf geführt, wo die Druckfarbe erhitzt wird und durch Blasenbildung auf einen Aufzeichnungsträger übertragen wird. Beim Mehrfarbdruck werden entsprechend der Farbenanzahl mehrere Umdruckstellen benötigt.From EP-A-0 202 370 a thermal transfer printing device with several thermal printheads is known. Each thermal print head is used to transfer an ink to a recording medium. Each thermal print head is assigned a cassette which has an ink reservoir in which the openings of an ink film are filled with ink. The ink film is passed over the thermal print head, where the ink is heated and transferred to a recording medium by bubbling. With multi-color printing, several transfer points are required depending on the number of colors.

Der vorliegenden Erfindung liegt die Aufgabe zugrunde, eine Thermotransferdruckvorrichtung zur Übertragung eines Druckbildes auf einen Aufzeichßungsträger in einem Druck- oder Kopiergerät aufzuzeigen, die die Verwendung von konventionellen, großen thermischen Beanspruchungen nicht genügenden Druckfarben erlaubt, eine geringe Belastung des Aufzeichnungsträgers gewährleistet und eine hohe Druckgeschwindigkeit gestattet.The present invention has for its object to show a thermal transfer printing device for transferring a print image to a record carrier in a printing or copying machine, which allows the use of conventional, large thermal stresses insufficient inks, ensures a low load on the record carrier and allows a high printing speed .

Diese Aufgabe wird durch die im Patentanspruch 1 angegebenen Merkmale gelöst. Weiterbildungen und Ausgestaltungen der Erfindung sind in Unteransprüchen angegeben.This object is achieved by the features specified in claim 1. Further developments and refinements of the invention are specified in subclaims.

Durch die erfindungsgemäße Thermotransferdruckvorrichtung wird es möglich, konventionelle Farbstoffe beim Thermotransferdruck einzusetzen. Die Wärmeeinwirkung der an der Umdruckstelle vorgesehenen Heizvorrichtung ist auf die im ersten Gewebeband befindliche Flüssigkeit beschränkt. Diese Flüssigkeit wird verdampft und treibt dadurch die Druckfarbe partiell aus dem zweiten Gewebeband in Richtung des Aufzeichnungsträgers aus. Die auf dem Aufzeichnungsträger auftreffende Druckfarbe ist nur geringfügig erwärmt, wodurch der Aufzeichnungsträger thermisch nur geringfügig belastet wird. Da das Druckbild durch Verdampfen der Flüssigkeit im ersten Gewebeband an zwei unterschiedlichen Stellen erzeugt wird und damit die Gesamtenergie zur Erzeugung des Druckbildes an zwei voneinander beabstandeten Orten abgegeben wird, ist die thermische Belastung der an der Umdruckstelle befindlichen Heizvorrichtung vergleichsweise gering. Die Aufteilung der Druckenergie kann aber auch zur Steigerung der Druckgeschwindigkeit eingesetzt werden.The thermal transfer printing device according to the invention makes it possible to use conventional dyes in thermal transfer printing. The heat effect of the heating device provided at the transfer printing point is limited to the liquid located in the first fabric band. This liquid is evaporated and thereby partially drives the printing ink out of the second fabric tape in the direction of the recording medium. The ink striking the recording medium is only slightly warmed, which means that the recording medium is only slightly thermally stressed. Since the print image is generated by evaporation of the liquid in the first fabric belt at two different locations and thus the total energy for generating the print image is given off at two spaced-apart locations, the thermal load on the heating device located at the transfer location is comparatively low. The division of the printing energy can also be used to increase the printing speed.

Die Gewebebänder haben die Eigenschaft, Flüssigkeit bzw. Druckfarbe aufzunehmen und diese partiell wieder abzugeben. Der Begriff Gewebeband bezieht sich deshalb auch auf Bänder mit nicht regelmäßiger Struktur, wie z.B. ein Fließ, und alle sonstigen Materialien, die die genannte Funktionalität aufweisen.The fabric tapes have the property of absorbing liquid or printing ink and partially releasing it again. The term fabric tape therefore also refers to tapes with a non-regular structure, such as a flow, and all other materials that have the functionality mentioned.

Gemäß einer Ausgestaltung und Weiterbildung der Erfindung enthält die Thermotransferdruckvorrichtung eine Einfärbestation, bei der eine farbtragende Walze durch wahlweises Hinbewegen einer Gegendruckrolle zur farbtragenden Walze mit dem zwischen der Walze und der Gegendruckrolle befindlichen zweiten Gewebeband in Berührungskontakt bringbar ist. Dadurch ist gewährleistet, daß nur an den Stellen des zweiten Gewebebandes Druckfarbe aufgebracht wird, wo dies erforderlich ist. Beispielsweise brauchen nur die Stellen eines in Endlosform vorliegenden zweiten Gewebebandes neu mit Druckfarbe beaufschlagt werden, aus denen in einem vorhergehenden Umdruckvorgang Farbe entnommen worden war.According to an embodiment and development of the invention, the thermal transfer printing device contains a dyeing station in which an ink-carrying roller can be brought into contact by selectively moving a counter-pressure roller toward the ink-carrying roller with the second fabric tape located between the roller and the counter-pressure roller. This ensures that printing ink is only applied at the points on the second fabric band where this is necessary. For example, only the locations of a second web of fabric in endless form need to be re-applied with printing ink from which ink had been taken in a previous transfer printing operation.

Gemäß einer weiteren Ausgestaltung der Erfindung sind mindestens zwei farbtragende Walzen in Laufrichtung des zweiten Gewebebandes hintereinander angeordnet. Damit sind an den gewünschten Stellen abschnittsweise hintereinander unterschiedliche Farben auf das zweite Gewebeband aufbringbar. Ein Mehrfarbdruck ist damit mit nur einem farbtragenden Gewebeband möglich. Vorzugsweise werden zwischen den einzelnen Abschnitten unterschiedlicher Einfärbung auf dem zweiten Gewebeband nicht mit Druckfarbe benetzte Abschnitte freigelassen. Im Falle einer Druckpause werden diese farbfreien Bereiche dann über der Heizvorrichtung der Umdruckstelle positioniert.According to a further embodiment of the invention, at least two ink-bearing rollers are arranged one behind the other in the running direction of the second fabric belt. In this way, different colors can be applied to the second fabric tape in sections at the desired locations. Multi-color printing is therefore possible with only one color-bearing fabric tape. Sections which are not wetted with printing ink are preferably left free between the individual sections of different coloring on the second fabric band. In the event of a print pause, these color-free areas are then positioned over the heating device of the transfer printing point.

Gemäß einer weiteren Weiterbildung und Ausgestaltung der Erfindung enthält die Druckbildübertragungsstelle einen Thermokamm mit unabhängig voneinander aktivierbaren Heizelementen, wobei ein Heizelement einem Pixel entspricht. Mit Hilfe des Thermokamms ist die Flüssigkeit aus dem ersten Gewebeband gemäß der vorliegenden Druckinformation partiell verdampfbar. Die Punktgröße und Farbdichte, die beim nachfolgenden Umdruck in der Umdruckstation erzielt werden soll, kann sowohl durch Variation der Heizenergie an der Heizvorrichtung der Umdruckstation, als auch durch die Variation der Heizenergie der Heizelemente des Thermokamms bestimmt werden. Als nichttoxische Flüssigkeit, mit der das erste Gewebeband benetzbar ist, eignet sich Wasser. Beim Verdampfen von Wasser treten keine toxischen Dämpfe auf, die die Umgebungsluft des Druckers oder die Funktionselemente im Inneren des Druckers beeinträchtigen könnten. Der Wasserdampf kann durch eine Absaugvorrichtung beseitigt werden. Es eignen sich aber auch andere, nichttoxische Flüssigkeiten, die einen entsprechenden Verdampfungspunkt haben und keine schädlichen Umwelteinflüsse hervorrufen.According to a further development and refinement of the invention, the print image transfer point contains a thermal comb with heating elements which can be activated independently of one another, a heating element corresponding to a pixel. With the help of the thermal comb, the liquid from the first fabric band can be partially evaporated according to the available pressure information. The dot size and color density, which is to be achieved in the subsequent transfer printing in the transfer printing station, can be determined both by varying the heating energy on the heating device of the transfer printing station and by varying the heating energy of the heating elements of the thermal comb. Water is suitable as the non-toxic liquid with which the first fabric band can be wetted. When water evaporates, there are no toxic vapors that could affect the ambient air of the printer or the functional elements inside the printer. The water vapor can be removed by a suction device. However, other non-toxic liquids that have a corresponding evaporation point and do not cause any harmful environmental influences are also suitable.

Im folgenden wird ein Beispiel der Erfindung anhand der Zeichnung näher erläutert.An example of the invention is explained in more detail below with reference to the drawing.

Die Figur zeigt eine Thermotransferdruckvorrichtung mit einem ersten und einem zweiten Gewebeband.The figure shows a thermal transfer printing device with a first and a second fabric ribbon.

Die Figur zeigt eine Thermotransferdruckvorrichtung zur Übertragung eines Druckbildes auf einen Aufzeichnungsträger 9 in einem Druck- oder Kopiergerät. Der Aufzeichnungsträger 9 wird in Aufzeichnungsträgertransportrichtung 14 einer Umdruckstelle 12 zugeführt. An der Umdruckstelle 12 wird eine auf einem zweiten Gewebeband 4 befindliche Druckfarbe 11 gemäß einer auf einem ersten Gewebeband 1 befindlichen Druckinformation auf den Aufzeichnungsträger 9 übertragen.The figure shows a thermal transfer printing device for transferring a print image to a recording medium 9 in a printing or copying machine. The record carrier 9 is fed to a transfer point 12 in the record carrier transport direction 14. At the transfer printing location 12, an ink 11 located on a second fabric tape 4 is transferred to the recording medium 9 in accordance with print information located on a first fabric tape 1.

Das erste Gewebeband 1 ist als Endlosband ausgeführt. Es ist zwischen zwei Walzen 10,16, deren Achsen parallel verlaufen, eingespannt. Eine der Walzen 10 ist der Umdruckstelle 12 zugeordnet, und die andere Walze 16 ist einem Feuchtwerk 2 zugeordnet. Das erste Gewebeband 1 ist mindestens so breit wie der breiteste, zu verarbeitende Aufzeichnungsträger 9. Die Länge des ersten Gewebebandes 1 ist so gewählt, daß der Abstand zwischen den beiden Walzen 10, 16, auf die das erste Gewebeband 1 gespannt ist, so groß ist, daß in diesem Abstandsbereich eine Druckbildübertragungsstelle 3 anordenbar ist.The first fabric belt 1 is designed as an endless belt. It is clamped between two rollers 10, 16, the axes of which run parallel. One of the rollers 10 is assigned to the transfer printing point 12, and the other roller 16 is assigned to a dampening unit 2. The first fabric tape 1 is at least as wide as the widest record carrier 9 to be processed. The length of the first fabric tape 1 is selected so that the distance between the two rollers 10, 16, on which the first fabric tape 1 is stretched, is so great that a print image transfer point 3 can be arranged in this distance range.

Die Druckbildübertragungsstelle 3 enthält eine Heizvorrichtung 13, mit der gemäß der vorliegenden Druckinformation eine im ersten Gewebeband 1 enthaltende nichttoxische Flüssigkeit 19 partiell verdampfbar ist. Als Heizvorrichtung 13 dient ein Thermokamm 13, wie er beispielsweise aus der eingangs zitierten US-A-4 731 619 bekannt ist. Der Thermokamm 13 enthält eine Mehrzahl von Heizelementen, denen jeweils ein Pixel der Druckinformation zuordenbar ist. Als Heizvorrichtung 13 könnte aber auch ein Laser oder eine Infrarotlichtquelle, die entsprechend steuerbar sind, eingesetzt werden.The print image transfer point 3 contains a heating device 13 with which, according to the available print information, a non-toxic liquid 19 contained in the first fabric band 1 can be partially evaporated. A thermal comb 13, as is known, for example, from US Pat. No. 4,731,619 cited at the beginning, serves as the heating device 13. The thermal comb 13 contains a plurality of heating elements, each of which can be assigned a pixel of the printing information. A laser or an infrared light source, which can be controlled accordingly, could also be used as the heating device 13.

Der Thermokamm 13 erstreckt sich über die gesamte Breite des ersten Gewebebandes 1. Das erste Gewebeband 1 wird unmittelbar über den Thermokamm 13 geführt. An der vom Thermokamm 13 abgewandten Seite des ersten Gewebebandes 1 ist eine Absaugvorrichtung 18 vorgesehen, die die verdampfte Flüssigkeit 19 absaugt. Die Flüssigkeit 19, beispielsweise Wasser, kann in einer der Absaugvorrichtung 18 nachgeordneten Kondensationseinrichtung (nicht dargestellt), kondensiert und dem Feuchtwerk 2 wieder zugeführt werden.The thermal comb 13 extends over the entire width of the first fabric band 1. The first fabric band 1 is guided directly over the thermal comb 13. On the side of the first fabric belt 1 facing away from the thermal comb 13, a suction device 18 is provided which sucks off the vaporized liquid 19. The liquid 19, for example water, can be condensed in a condensation device (not shown) arranged downstream of the suction device 18 and can be fed back to the dampening unit 2.

An der Druckbildübertragungsstelle 3 werden aus dem als Edelstahldrahtgewebe mit einer Gewebefeinheit > 200 mesh ausgebildeten ersten Gewebeband 1 an den Stellen Flüssigkeit 19 verdampft, an denen kein Farbauftrag auf dem Aufzeichnungsträger 9 erfolgen soll. Nach Durchlauf des ersten Gewebebandes 1 durch die Druckbildübertragungsstelle 3 befindet sich also nur noch an den Stellen Flüssigkeit 19 im ersten Gewebeband 1, an denen ein Farbauftrag auf den Aufzeichnungsträger 9 erfolgen soll.At the print image transfer point 3, liquid 19 is evaporated from the first fabric band 1, which is designed as a stainless steel wire mesh with a mesh fineness> 200 mesh, at those points at which no ink is to be applied to the recording medium 9. After the first fabric tape 1 has passed through the print image transfer point 3, there is therefore only liquid 19 in the first fabric tape 1 at those locations where ink is to be applied to the recording medium 9.

Diese im ersten Gewebeband 1 verbleibende Flüssigkeit 19 wird an der Umdruckstelle 12 durch die als Heizvorrichtung dienende Heizwalze 10 verdampft, wodurch das Druckbild auf den Aufzeichnungsträger 9 gelangt. Im ersten Gewebeband 1 befindet sich demzufolge nach Durchlauf der Umdruckstelle 12 keine Flüssigkeit 19 mehr. Neue Flüssigkeit 19 wird im Feuchtwerk 2 wieder in das erste Gewebeband 1 übertragen. Das Feuchtwerk 2 weist zwei aufeinander abrollende Walzen 16,17 auf, zwischen denen das erste Gewebeband 1 hindurchtransportierbar ist. Eine der beiden Walzen 17 taucht in die in der Wanne des Feuchtwerks 2 befindliche Flüssigkeit 19 ein. Dabei wird die Walze 17 mit Flüssigkeit 19 benetzt. Die Flüssigkeit 19 wird durch das Abrollen der Walze 17 auf dem ersten Gewebeband 1 auf das erste Gewebeband 1 übertragen. Beim Verlassen des Feuchtwerks 2 ist das erste Gewebeband 1 vollständig mit Flüssigkeit 19 benetzt.This liquid 19 remaining in the first fabric tape 1 is evaporated at the transfer location 12 by the heating roller 10 serving as a heating device, as a result of which the printed image reaches the recording medium 9. Accordingly, there is no longer any liquid 19 in the first fabric belt 1 after passing through the transfer printing point 12. New liquid 19 is transferred back into the first fabric belt 1 in the dampening unit 2. The dampening unit 2 has two rollers 16, 17 rolling on top of one another, between which the first fabric belt 1 can be transported. One of the two rollers 17 is immersed in the liquid 19 located in the tub of the dampening unit 2. The roller 17 is wetted with liquid 19. The liquid 19 is transferred to the first fabric belt 1 by rolling the roller 17 on the first fabric belt 1. When leaving the dampening unit 2, the first fabric band 1 is completely wetted with liquid 19.

Das zweite Gewebeband 4 ist ebenso wie das erste Gewebeband 1 als Endlosband ausgeführt. Das zweite Gewebeband 4 besteht aus Polyester oder metallisiertem Polyester mit einer Gewebedicke von < 100µm. Das zweite Gewebeband 4 weist mindestens eine Breite auf, die der Breite des breitesten zu bedruckenden Aufzeichnungsträgers 9 entspricht. Das zweite Gewebeband 4 ist über drei Walzen 10, 20, 21, deren Achsen parallel zueinander sind, geführt. Im Bereich der Heizwalze 10 befindet sich das erste Gewebeband 1 zwischen der Heizwalze 10 und dem zweiten Gewebeband 4. Bewegungsrichtung und Geschwindigkeit der Bänder 1,4 sind identisch.The second fabric belt 4, like the first fabric belt 1, is designed as an endless belt. The second fabric tape 4 consists of polyester or metallized polyester with a fabric thickness of <100 microns. The second fabric tape 4 has at least a width which corresponds to the width of the widest record carrier 9 to be printed. The second fabric belt 4 is guided over three rollers 10, 20, 21, the axes of which are parallel to one another. In the area of the heating roller 10, the first fabric belt 1 is located between the heating roller 10 and the second fabric belt 4. The direction of movement and speed of the belts 1, 4 are identical.

Vor Erreichen der Umdruckstelle 12 durchläuft das zweite Gewebeband 4 eine Einfärbestation 5. In der Einfärbestation 5 werden wahlweise vier unterschiedliche Druckfarben 11 auf das zweite Gewebeband 4 aufgebracht. Die Einfärbestation 5 kann dabei modulartig aufgebaut sein, wodurch jede beliebige Anzahl von Druckfarben 11 auf das zweite Gewebeband 4 auftragbar sind. Der Farbauftrag erfolgt jeweils durch eine farbtragende Walze 7, die auf einer Seite des zweiten Gewebebandes 4 angeordnet ist. Auf der gegenüberliegenden Seite des zweiten Gewebebandes 4 ist der farbtragenden Walze 7 eine Gegendruckrolle 6 zugeordnet. Diese Gegendruckrolle 6 ist senkrecht zur Oberfläche des zweiten Gewebebandes 4 bewegbar. Soll ein Farbauftrag erfolgen, wird die Gegendruckrolle 6 zur farbtragenden Walze 7 bewegt. Bei dieser Bewegung trifft die Gegendruckrolle 6 auf dem zweiten Gewebeband 4 auf und bewegt dieses zur farbtragenden Walze 7. Dadurch gelangen das zweite Gewebeband 4 und die farbtragende Walze 7 in Berührungskontakt, wodurch Druckfarbe 11 von der farbtragenden Walze 7 auf das zweite Gewebeband 4 übertragen wird. Die farbtragende Walze 7 wird durch eine Abrollbewegung auf einer Versorgungswalze 22, die in einen Farbvorrat 11 eintaucht, stets mit Druckfarbe 11 benetzt.Before the transfer point 12 is reached, the second fabric tape 4 passes through a dyeing station 5. In the inking station 5, four different printing inks 11 are optionally applied to the second fabric tape 4. The inking station 5 can be constructed in a modular manner, as a result of which any number of printing inks 11 can be applied to the second fabric tape 4. The ink is applied in each case by an ink-bearing roller 7, which is arranged on one side of the second fabric belt 4. On the opposite side of the second fabric belt 4, the ink-bearing roller 7 is assigned a counter-pressure roller 6. This counter pressure roller 6 is movable perpendicular to the surface of the second fabric belt 4. If ink is to be applied, the counter-pressure roller 6 is moved to the ink-bearing roller 7. During this movement, the counter-pressure roller 6 hits the second fabric belt 4 and moves it to the ink-bearing roller 7. This brings the second fabric belt 4 and the ink-bearing roller 7 into contact, as a result of which ink 11 is transferred from the ink-bearing roller 7 to the second fabric belt 4 . The ink-bearing roller 7 is always wetted with printing ink 11 by a rolling movement on a supply roller 22, which is immersed in an ink supply 11.

Durch eine nicht dargestellte Steuereinrichtung wird sichergestellt, daß jeweils nur eine Gegendruckrolle 6 zu einer farbtragenden Walze 7 gedrückt wird. Dadurch sind auf dem zweiten Gewebeband 4 Abschnitte unterschiedlicher Einfärbung erzeugbar. Zwischen den einzelnen Abschnitten werden Bereiche ohne Druckfarbe 11 vorgesehen, so daß bei einer Umdruckpause einer dieser freien Bereiche an der Umdruckstelle 12 in den Einflußbereich der Heizvorrichtung 10 gesteuert werden kann.A control device (not shown) ensures that only one counter-pressure roller 6 is pressed to an ink-bearing roller 7. As a result, 4 sections of different colors can be produced on the second fabric tape. Areas without printing ink 11 are provided between the individual sections, so that during a transfer printing break one of these free areas at the transfer printing location 12 can be controlled into the area of influence of the heating device 10.

Die Übertragung des Druckbildes auf den Aufzeichnungsträger 9 erfolgt in der Umdruckstelle 12. An den Stellen, an denen sich Flüssigkeit 19 im ersten Gewebeband 1 befindet, findet ein Verdampfungsprozeß in der Umdruckstelle 12 statt. Der Aufzeichnungsträger 9 wird durch ein als Gegendruckrolle 8 ausgebildetes Andruckelement, das in Richtung 15 senkrecht zum Aufzeichnungsträger 9 zur Heizwalze 10 bewegbar ist, in Berührungskontakt mit dem zweiten Gewebeband 4 gebracht. Eine an dieser Berührungsstelle im zwischen zweitem Gewebeband 4 und Heizwalze 10 befindlichen ersten Gewebeband 1 vorliegende Flüssigkeit 19, wird verdampft. Die verdampfende Flüssigkeit 19 treibt die Druckfarbe 11 aus dem zweiten Gewebeband 4 aus, wodurch sich diese auf dem Aufzeichnungsträger 9 niederschlägt.The transfer of the print image to the recording medium 9 takes place in the transfer printing point 12. At the points where liquid 19 is in the first fabric belt 1, an evaporation process takes place in the transfer printing point 12. The recording medium 9 is brought into contact with the second fabric belt 4 by a pressure element 8 designed as a counter pressure roller 8, which can be moved in the direction 15 perpendicular to the recording medium 9 to the heating roller 10. A liquid 19 present at this point of contact in the first fabric belt 1 located between the second fabric belt 4 and the heating roller 10 is evaporated. The evaporating liquid 19 drives the printing ink 11 out of the second fabric tape 4, as a result of which this is deposited on the recording medium 9.

Claims (10)

  1. A thermal transfer printing device for transferring a printing image onto a recording medium (9) in a printer or copier, with
    - a first fabric tape (1) which can be wetted with a liquid (19),
    - a printing image transfer point (3) at which the liquid (19) can be partially evaporated out of the first fabric tape (1) according to the existing printing information,
    - a second fabric tape (4), onto which printing ink (11) can be transferred in an inking station (5), and
    - a transfer printing point (12), at which
    - the first fabric tape (1) and the second fabric tape (4) are jointly guided, one on top of the other, over a heating device (10), the first fabric tape (1) being in touch contact with the heating device (10), with the result that the liquid (19) contained in the first fabric tape (1) evaporates, and
    - the recording medium (9) can be pressed relative to the second fabric tape (4) in the direction of the heating device (10) by a pressure element (8).
  2. The thermal transfer printing device as claimed in claim 1, with a first fabric tape (1) composed of a high-grade steel wire fabric.
  3. The thermal transfer printing device as claimed in one of claims 1 or 2, with a polyester fabric serving as a second fabric tape (4) and having a fabric thickness of < 100 µm.
  4. The thermal transfer printing device as claimed in one of the preceding claims, with a heating device extending transversely relative to the direction of transport (14) of the recording medium (9) and designed as a heatable roller (10).
  5. The thermal transfer printing device as claimed in one of the preceding claims, with an inking station (5), at which, by the selective movement of a backing roll (6), an ink-carrying roller (7) can be brought into touch contact with the second fabric tape (4).
  6. The thermal transfer printing device as claimed in claim 5, in the inking station (5) of which at least two ink-carrying rollers (7) are arranged in succession in the direction of run of the second fabric tape (4).
  7. The thermal transfer printing device as claimed in one of the preceding claims, with a printing image transfer point (3) which has a thermal comb (13) having heating elements activatable independently of one another, one heating element corresponding to one pixel.
  8. The thermal transfer printing device as claimed in one of the preceding claims, with a dampening unit (2) which is arranged at the first fabric tape (1) and in which the first fabric tape (1) can be wetted with nontoxic liquid (19).
  9. The thermal transfer printing device as claimed in claim 8, in which the dampening unit (2) contains two rollers (16, 17) rolling one on the other, between which the first fabric tape (1) can be transported through and one of which transfers the liquid (19) onto the first fabric tape (1).
  10. The thermal transfer printing device as claimed in one of the preceding claims, with fabric tapes (1, 4) designed as endless tapes.
EP95901344A 1994-02-23 1994-11-29 Thermotransfer printing device for transferring an image to a substrate Expired - Lifetime EP0746470B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE4405840 1994-02-23
DE4405840 1994-02-23
PCT/DE1994/001418 WO1995023065A1 (en) 1994-02-23 1994-11-29 Thermotransfer printing device for transferring an image to a substrate

Publications (2)

Publication Number Publication Date
EP0746470A1 EP0746470A1 (en) 1996-12-11
EP0746470B1 true EP0746470B1 (en) 1997-10-22

Family

ID=6511004

Family Applications (1)

Application Number Title Priority Date Filing Date
EP95901344A Expired - Lifetime EP0746470B1 (en) 1994-02-23 1994-11-29 Thermotransfer printing device for transferring an image to a substrate

Country Status (5)

Country Link
US (1) US5801742A (en)
EP (1) EP0746470B1 (en)
JP (1) JPH09509112A (en)
DE (1) DE59404446D1 (en)
WO (1) WO1995023065A1 (en)

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH548866A (en) * 1971-11-17 1974-05-15 Battelle Memorial Institute PRINTING DEVICE WITH LIQUID INK, CONDUCTING ELECTRICITY.
JPS61197246A (en) * 1985-02-28 1986-09-01 Toshiba Corp Recording device
DE3573753D1 (en) * 1985-03-27 1989-11-23 Elm Corp Thermal ink jet printer
DE3577674D1 (en) * 1985-05-20 1990-06-21 Elm Corp PRINT HEAD.
US4731619A (en) * 1985-07-18 1988-03-15 Kabushiki Kaisha Toshiba Thermal printing head
JP2777900B2 (en) * 1989-03-15 1998-07-23 富士通株式会社 Recording device
JPH03254948A (en) * 1990-03-06 1991-11-13 Nec Corp Thermal ink jet image forming apparatus
US5159357A (en) * 1990-06-26 1992-10-27 Eastman Kodak Company Non-impact printer for recording in color
US5175568A (en) * 1990-10-24 1992-12-29 Ricoh Company, Ltd. Process and apparatus for forming image on novel recording medium
JPH0664289A (en) * 1992-08-24 1994-03-08 Oki Electric Ind Co Ltd Ink sheet regenerating method and ink sheet regenerating type thermal transfer recording apparatus

Also Published As

Publication number Publication date
EP0746470A1 (en) 1996-12-11
DE59404446D1 (en) 1997-11-27
US5801742A (en) 1998-09-01
WO1995023065A1 (en) 1995-08-31
JPH09509112A (en) 1997-09-16

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