JP2007276466A - Image transfer printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a normal temperature film transferring method so that transferring of a thicker layer may be attained. <P>SOLUTION: This invention describes various transfer printing methods in which an image motif of a transfer film is transferred to a printing sheet transferred by an offset printing press. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image transfer printing method used in a sheet-fed rotary printing press.

  So-called thermal film embossing is widely used as a transfer method in the printing industry. In thermal film embossing, a transfer film having a wax layer as a separation layer is usually used. Next, an imaging layer, usually a metal layer, is spread on such a separating layer. The metal layer is partially transferred from the support material to the printing material by the heated press die.

  Since the resolution of the image structure is relatively low and the processing speed is high, the room temperature transfer method is widely practiced on the first line in the printing industry. Thus, EP 0 695 520 describes a printing material and a printing method using this material. There is shown a sheet processing machine including a paper feeding device and a paper discharging device, and a printing mechanism and a coating mechanism arranged between these units. In at least one printing mechanism, an adhesive pattern is applied by a lithographic printing method. This adhesive pattern is spread by a room temperature printing method and has a specific imaging theme. A film guide is provided in a coating mechanism including an impression cylinder and a press roll after the printing mechanism. This is configured in the art such that a film strip or transfer film is guided from a film storage roller through a printing slit between an impression cylinder and a press roll. As the sheets are transported through the printing mechanism, an adhesive pattern is formed on each sheet. Thereafter, the printing sheet is guided through a coating mechanism, and the printing sheet placed on the impression cylinder is combined with the film material by a press roller. In doing so, the mostly metal layer below is in close contact with the area with the adhesive. After further transfer of the printed sheet, the transferred layer sticks only in the areas with the pattern adhesive. Thus, the carrier film only removes the transfer layer in the area of the adhesive pattern. The transfer film used in this way is wound again. It is known to use such a coating mechanism in, for example, a printing mechanism of a printing press. Furthermore, it is also known to use, for example, a rubber cylinder or impression cylinder of a printing mechanism as a press roller.

  The disadvantage of such a device is that it operates with two printing mechanisms. Accordingly, the pamphlet of International Publication No. 2005/10028 describes a development of a room temperature transfer method that is performed using individual elements in the printing mechanism. In the first embodiment, the adhesive pattern is transferred directly to the printing material. The desired subject imaging layer is then transferred directly to the printing material by a press slit. In the patent specification, it is also proposed to control the film feed so that the transfer film is stopped when the image forming layer or the metallized layer is not transferred. Both European Patent Application Nos. 0 695 520 B1 and WO 2005/100028 have positions where the image is structured by application of an adhesive and the transfer film is in contact with the imaged adhesive application part. Thus, it is common that the transfer layer is peeled off from the transfer film support film.

  However, it is obvious to anyone that the room temperature film transfer method can transfer only a relatively thin transfer layer because the adhesive force to peel away the layer that would otherwise be transferred is insufficient. Furthermore, a thicker layer means a stronger bonding relationship inside the transfer layer. Therefore, sharp edge delamination as required in the print area is not obtainable with most materials. In addition, a greater range of delamination is expected if the adhesive strength of the adhesive is generally sufficient to delaminate the transfer layer. This results in particles that not only lack the edge sharpness but also do not stick to the printed circuit board outside the adhesive application area. This can cause printed image failure and machine smearing.

  However, many applications are known that require thicker layers. An example is a tactile surface transfer, a transfer of a rubbing field to cover the lottery field, or a conductive layer in low cost electronic component applications.

The room temperature transfer method as disclosed in European Patent Application No. 0659520 and International Publication No. 2005/100028 requires a high-cost manufacturing method that cannot be expressed by simple elements of a known room temperature transfer method. Therefore, it is only suitable for the transfer of expensive safety elements under certain conditions. However, the hologram can be transferred by a transfer method to a substrate, as seen in many applications. Typically, a heated film embossing method is employed for the transfer of such holograms and other expensive safety elements. The known heated film embossing method is a static printing method, ie transfer of variable image data is not possible. Variable image data is, for example, numbering or even personalized text or changing images.
European Patent Application No. 0659520 International Publication No. 2005/100028 Pamphlet

  An object of the present invention is to improve a known room temperature film transfer method so that a thicker layer can be transferred by such a method. In one development, a method is developed that can also transfer safety elements such as holograms.

  The transfer of thick layers in the room temperature transfer method basically involves imprinting an image motif, such as an image, circuit, antenna, alphanumeric text, or tactile structure on the transfer belt, and this imprinted motif on the outside of the press roller. This is done by winding around. The imprinted motif is transferred in a press slit between the press roller and the impression cylinder after an adhesive is applied to the printing substrate. Adhesive and film application to the printed circuit board is performed in front of the press slit between the press roller and impression cylinder by a printing mechanism or other suitable device such as a spray nozzle. It is spread along the surface or motif of the part. In another aspect of the invention, rather than the adhesive being applied to the printed circuit board as in the exemplary embodiment described above, the adhesive is applied directly to the transfer belt before the transfer belt passes through the press slit. The Known devices such as roller mechanisms, flexographic printing mechanisms, spray nozzles, and all suitable devices are used to apply the adhesive to the transfer belt.

  One or more ink jet devices having a flexographic mechanism, in particular a flexographic printing mechanism having a chamber doctor blade and a raster roller, or a flat screen printing mechanism, a rotating screen printing mechanism or an intaglio printing mechanism. Is done by. The press roller may be a separate roller that contacts the impression cylinder of the printing press during the transfer operation, or the press roller is a rubber cylinder of the printing mechanism or a plate cylinder of the varnish coating mechanism.

  In an advantageous refinement of this claim of the invention, the imprinted motif on the transfer belt is dried or cured and transferred from the transfer belt to the printing substrate. This has the advantage that the printed layer is not crushed in the press slit between the press roller and the impression cylinder. A dried printing motif can be realized by using a fast drying ink or coating. Such an ink or coating can be, for example, a waxy printing ink or coating, or a printing ink or coating containing a solvent. Alternatively, the printing motif may be transferred to a transfer belt and then dried or cured by a drying or curing device. Examples of such drying devices would be hot air dryers (convection dryers), infrared dryers, ultraviolet or electron beam dryers or radiation dryers such as microwave dryers.

  In the present invention, the transfer belt is wound again in the press slit between the press roller and the impression cylinder after transferring the printing motif from the transfer belt to the printing substrate. Therefore, the transfer belt is used disposable and discarded after transfer. In the claimed development according to the invention, the transfer belt is also used in a circulating manner. That is, the transfer belt may be washed after transfer to be newly provided with a motif. In any case, it is advantageous to synchronize the transfer belt and the printing machine so that the printed image printed by the printing machine and the transferred image match. Synchronization can be achieved by utilizing one or more measurement marks on the transfer belt with a suitable sensor, for example an optical sensor. The detected error can be adjusted and corrected by a floating roller or an electric drive. A mechanical synchronization is also conceivable in which the transfer belt is provided with a row of holes in the horizontal direction and the pins of the synchronizing roller are fitted there.

  Next, the present invention will be described in detail with reference to the drawings.

  In the present invention, it is important that the transfer printing method described above is basically provided in all the apparatuses shown in FIGS.

  In the exemplary embodiment shown in FIG. 1, embodiments according to the present invention are described in the form of using a disposable transfer belt. On the other hand, although the drawing of the embodiment using the circulation type transfer belt according to the present invention is omitted, in this case, there is no unwinding station 8 and no take-up station 9, and the transfer belt 5 operates in a circulating manner via a guide roller. It will be obvious to any person skilled in the art what can be done. The circulation type transfer belt has an advantage that an expensive printing mechanism such as a flexo or screen printing mechanism can be easily incorporated by omitting the film storage roll 8 and the film collection roll 9. As shown in FIG. 1, the transfer belt 5 is unwound from the film storage roller 8 and subsequently printed by a printing device 27, here shown as an ink jet device. After the printing process by the printing device 27, the printing ink or coating applied to the transfer belt is optionally dried or cured by a drying or curing device 28. The position of the transfer belt relative to the cylinder position of the rubber cylinder 3 is evaluated in this example by one or more sensors 29 that determine the position of the front, back or both sides of the transfer film 5 based on measurement marks or other characteristics. The In some cases, the necessary correction of the transfer belt position is performed by floating roller control, and the floating roller can be introduced at an arbitrary position in the belt running path of the transfer belt. This position can also be synchronized with the roller drive 7. It may be advantageous to use the guide roller 14 as a floating roller so that correction can be performed as close as possible to the transfer slit 6. In the case of mechanical synchronization, the guide roller 14 is provided with a bolt that is fitted in the row of holes in the horizontal direction of the transfer belt 5 in the horizontal direction. Each roller in contact with the transfer belt 5 can be used for synchronization in the present invention.

  In a further development of the invention, the transfer belt is disposable by winding and unwinding or the transfer belt operating in a circulating manner is printed with waxy printing ink from a heated printing device. This waxy printing ink has the advantage that it cures relatively quickly and therefore does not bleed. Thereafter, the feed roller acting on the impression cylinder is heated to dissolve the ink, whereby the image imprinted on the transfer belt can be transferred. Alternatively or additionally, the print motif on the transfer belt can be heated by a heating device. Thereby, the print image can be easily transferred to the printing material. This solution also makes it possible to print variable data in an excellent manner. When printing a printing sheet directly on a variable data printing machine, such as a sheet-fed rotary printing machine having an ink jet printer, the printing device, There is a problem that the distance between the print head of the printer and the print substrate is not always kept constant. This problem can be avoided because the distance between the transfer belt and the printing device can be kept constant with a simple device by the selected device having the transfer belt and the pressure roll that also serves as a sheet guide. Residues from the waxy printing ink of the printing motif are also heated by the printing ink residue immediately before the washing station by one or more heating devices or by contact with one or more heated rollers, It can be easily removed from the transfer belt by a suction sponge roller or scraper.

  In another development, the transfer belt is printed with one or more sublimation inks. The sublimation printing method involves the transition of a printing ink containing one or more pigments from a solid to a gaseous state without liquefaction using heat and, in some cases, pressure, and this gaseous pigment is applied to the product to be decorated. To penetrate. The gaseous one or more dyes are transferred again to a product or printed substrate that is decorated in a solid state and is fixed in the product. This method is known as sublimation printing or sublimation method. Similar methods are also used in thermal sublimation printing methods. In this case according to the invention, the press roller 3 is brought into contact with the printing substrate and heated so that the dye can be sublimated onto the printing material. The transfer belt 5 can be preheated to a temperature slightly below the temperature at which the sublimation process begins by a suitable heating device or drying device 28 before passing through the transfer slit 6.

  In another aspect of the invention, a so-called transfer image method is used. In this case, the motif is printed on the transfer belt using a printing ink that can be activated by water or water vapor. In this case, the printed image is moistened in the transfer slit 6 by an appropriate device before passing through the transfer belt 5. This can be done by a steam device, a spray device or a roller mechanism.

  However, in many applications, the image motif on the transfer belt in the printing press cannot be produced economically and technically meaningful in terms of finishing technology. This is the case, for example, with holograms used for manufacturing security. Such a hologram passes through a complicated multi-stage manufacturing process that is difficult to use in a printing machine manufacturing environment. Another example is an antenna that can be used in RFID (Radio Frequency Identification System) applications. Such antennas are now most often etched, but this is a process that proceeds slowly and therefore is not compatible with the high speed production rates of current printing presses. Wet chemical plants are also unthinkable for reasons of work safety around the printing press. For example, if the label has extended functionality, it would not make any sense to transfer the label completely. Another application would be the transfer of printed very invisible layers, such as those used in scraping lotteries. The printing inks used for this purpose usually contain a large proportion of solvent, so printing of such a layer is expensive for removal of the solvent, for example for suction with post-combustion. In such a case, it is effective to pre-print such a layer with a specialized printing machine.

  In the exemplary embodiment according to the invention, the film storage roller 8 on the transfer belt is a preprinted or prefinished motif, hologram or label. The various applications, pre-printed motifs, pre-finished motifs, the possibility of holograms or labels are briefly summarized below by the concept of transcription motifs. This transfer motif is transferred to the printing material in the transfer slit 6 by the press roller 3 or the feed roller 21. The transfer motif on the transfer belt can comprise an adhesive that is activated by pressure and / or heat. The transfer motif can comprise an adhesive (Leim) that is activated by applying moisture before passing through the transfer slit 6. The application of moisture can be performed using a device that directs water vapor onto the transfer belt or directly applies water by a suitable device such as a roller mechanism or a spray nozzle. Alternatively, an arbitrary adhesive can be spread on the transfer belt 5 using such an apparatus before passing through the transfer slit 6. Of course, the adhesive can be spread by an offset printing mechanism or a flexographic printing mechanism disposed in front of the transfer belt 6 in the sheet running direction of the printing press. In either case, in order to transfer the transfer motif to the correct position on the printing substrate, priority is given to the solvent in which the transfer belt operates in a contact manner. This is ideally one or more transfer belts which are juxtaposed in the axial direction of the impression cylinder 4 and each cover only a partial area of the printing width and can be driven independently of each other.

1 is a basic view of a sheet processing machine having an apparatus for carrying out a transfer printing method. It is a figure which shows the apparatus for implementing the transfer printing method in a work unit. It is a figure which shows the apparatus for implementing the transfer printing method which has a circulation type transfer belt.

Explanation of symbols

1 Spreading mechanism 2 Coating module 3 Press roller (rubber cylinder)
4 Impression cylinder 5 Transfer belt (transfer film) / film continuous sheet 6 Transfer slit 7 Roller drive device 8 Film storage roll (unwinding station)
9 Film collection roll (winding station)
DESCRIPTION OF SYMBOLS 10 Press cover 11 Ink / moisture mechanism 12 Plate cylinder 13 Rubber / impression cylinder 14 Guide device 15 Dirt 16 Ultraviolet dryer 17 Monitoring system 18 Floating roller 19 Cylinder groove 21 Feed roller 22 Guide roller 23 Guide roller 24 Plate cylinder 25 Spreading system 26 Dispensing system 27 Printing system 28 Drying system 29 Sensor for detecting register marks

Claims (38)

A transfer film used in a transfer printing method of an offset printer, preferably a sheet offset printer,
Said printing machine comprises a coating module (2) comprising at least one impression cylinder (4) forming a common transfer slit (6) and a pressing device,
The transfer film (5) is pressed together with the printing sheet in a state where the coated surface is placed on the printing sheet guided on the impression cylinder (4), and the pressing device and the impression cylinder (4). After being guided around the press device or substantially in contact with the press device so as to be guided through the transfer slit (6) between the print sheet and the print sheet after exiting the transfer slit (6) A transfer film on which the coating on the transfer film or a component of the coating remains on the printed sheet,
Transfer characterized in that the transfer film comprises an image motif, such as alphanumeric characters, patterns, image motifs, holograms, metal patterns or specially partially spread coatings, and is not coated on the entire surface the film.   The transfer film is imprinted with a motif by at least a suitable printing device (27) before passing through the transfer slit (6), and the motif is at least partially within the transfer slit (6). The transfer printing method using the transfer film according to claim 1, wherein the transfer printing method is performed.   The printing device (27) may be one or more flat screen printing devices, one or more rotary screen printing devices, one or more intaglio printing devices, or one or more ink jet printing devices, or an individual of the printing devices. The transfer printing method according to claim 2, which is a combination of or all of the above.   The motif spread on the transfer film (5) by the printing device (27) is cured and / or dried by an appropriate curing or drying device (28) before passing through the transfer slit (6). The transfer printing method according to claim 2 or 3, characterized by the above.   The curing or drying device (28) is formed by a convection drying device, an infrared drying device, an ultraviolet drying device, a microwave drying device, an electron beam drying device, or any combination of the drying or curing devices. The transfer printing method according to claim 4.   The film storage roll (8) is a separate transfer station wound around a whole roll or a plurality of partial rolls juxtaposed in the axial direction of the impression cylinder (4). 5), the transfer film (5) is then unwound from the film storage roll (8) during the printing operation and sent to the transfer slit (6), in which the one or more The transfer printing method according to claim 1, wherein the transfer motif in the transfer film is subsequently transferred to a print sheet.   The transfer printing method according to claim 6, wherein the transfer motif is an alphanumeric symbol and / or an image motif.   The transfer printing method according to claim 6, wherein the transfer motif is a hologram.   The transfer printing method according to claim 6, wherein the transfer motif relates to an antenna, a conductive layer, or a semiconductor layer.   The transfer printing method according to claim 6, wherein the transfer motif relates to an antenna or a single layer or multilayer label.   The transfer motif is the outermost layer facing the impression cylinder (4) in the transfer slit (6) and activated by a suitable device before the transfer film (5) passes through the transfer slit (6). The transfer printing method according to claim 6, further comprising an adhesive layer to be formed.   The adhesive layer on the transfer motif has a roller mechanism in which water vapor is introduced into the transfer film before the transfer film passes through the transfer slit (6), or water is sprayed onto the transfer film by a jetting device. 12. The transfer printing method according to claim 6, wherein the transfer printing method is activated when water is introduced into the transfer film by contact with the transfer film.   The adhesive layer on the transfer motif is activated by one or more suitable heating devices, such as infrared heaters, and / or by introducing heated air before the transfer film passes through the transfer slit (6) The transfer printing method according to claim 6, wherein the transfer printing method is a heat-activated adhesive layer.   On the side of the transfer film (5) facing the impression cylinder (4) in the transfer slit (6), the transfer film is partly or partially coated with adhesive by a suitable device before passing through the transfer slit. 11. Combined with at least one of claims 7 to 10, characterized in that the adhesive / glue is applied to the entire surface and serves to fix the transfer motif to the printed sheet. Or the transfer printing method according to any one of 6;   15. The transfer printing method according to claim 14, wherein the glue / adhesive application device is a roller coating device in contact with the transfer foil.   15. The transfer printing method according to claim 14, wherein the device for applying glue / adhesive is a contactless spraying device.   Before passing through the transfer slit (6), the print motif is peeled from the transfer film on the entire surface or a part by one or more printing mechanisms, and the transfer motif is fixed to the print sheet. The transfer printing method according to claim 4, wherein the transfer printing method is combined with at least one of claims 7 to 10.   The transfer printing method according to claim 17, wherein the adhesive is applied to the printing sheet by an offset printing mechanism.   The transfer printing method according to claim 17, wherein the adhesive is applied to the printing sheet by a flexo or varnish coating mechanism.   The transfer printing method according to claim 1, wherein the motif imprinted on the transfer film includes one or more sublimation dyes.   The transfer printing method according to claim 6, wherein the motif on the transfer film contains one or more sublimation dyes.   In the press device, for example, the press roller (3) or the feed roller (21), the sublimation dye layer on the side of the transfer film facing the impression cylinder (4) is heated higher than the sublimation temperature, and the sublimation dye The transfer printing method according to any one of claims 20 and 21, characterized in that is transferred to a gaseous state and heated so as to penetrate into the printing sheet on the impression cylinder (4).   23. The transfer printing method according to claim 22, wherein the press device is heated by a through-flow in the heated device.   The transfer printing method according to claim 22, wherein the press device is electrically heated.   The transfer printing method according to claim 22, wherein the press device is indirectly heated through thermal radiation.   The transfer film in front of the transfer slit (6) is heated to a temperature slightly lower than the sublimation temperature by an appropriate heating device, so that only the temperature difference from the sublimation temperature is transmitted to the heated press device. The transfer printing method according to claim 20, 21, or 22.   The motif printed on the transfer film is made of one or more printing inks that can be activated by moisture ("ink for transfer image method"). The transfer printing method described in 1.   The transfer printing method according to claim 6, wherein the motif on the transfer film is composed of one or a plurality of printing inks that can be activated by moisture (“ink for transfer image method”).   29. The transfer printing method according to claim 27, wherein moisture is introduced into the transfer film before passing through the transfer slit (6).   30. The transfer printing method according to claim 29, wherein the introduction of moisture into the transfer film is performed by introduction of water vapor, condensation by cooling of the transfer film, or a spraying device.   30. The transfer printing method according to claim 29, wherein the introduction of moisture is performed by a roller coating device.   The printing sheet on the impression cylinder (4) has a transfer image formed by printing ink that is partially or entirely exposed to moisture before passing through the transfer slit (6) and can be activated by moisture. 29. The transfer printing method according to claim 27, wherein the transfer printing is carried out on the printing sheet in the transfer slit (6).   The said transfer film is unwound from the film storage roll (8), sent to the said transfer slit (6), and is wound again by the film collection | recovery roll after transfer. The transfer printing method according to any one of the above.   The transfer film forms a circulation belt and passes through the printing device (27) and possibly another device via the guide device (14) and / or guide roller (22/23). 3. The method as claimed in claim 1, further comprising the step of feeding to the slit (6) and from there for a new coating by the printing device (27) via the guide device (14). The transfer printing method described in 1.   The transfer film (5) is provided with a row of holes or other openings running laterally outside the printing area, in which pins or journals ensure alignment of the transferred motif on the printing sheet. The pin or journal on one or more guide devices, or on one or more guide rollers (22), or on one or more guide rollers (22) or (23) or 35. The transfer printing system of claim 34, wherein the transfer printing system is on the press roller and the pin or journal fits in a row or opening of lateral holes as the film circulates.   The transfer film belt (5) includes a register mark on the back surface and / or the front surface, and the mark is disposed on one or both surfaces of the continuous film sheet immediately before the transfer slit (6). The signal detected and acquired by is used to control the position of the transfer film continuous sheet (5) in the transfer slit, the transfer slit being adapted to a motor controller and / or a floating roller 35. The transfer printing system having a circulation belt according to claim 34, characterized in that it is adapted to the position of the transfer film (5) in the transfer slit (6) via (18).   The transfer printing method according to claim 1, wherein the transfer film is continuously transferred through the transfer slit (6) during a transfer operation.   7. The one or more transfer films according to claim 1, wherein the one or more transfer films are transferred through the transfer slit (6) with timing adjustment during a transfer operation. Transfer printing method.

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