Patent Application
20090068340
This application claims the priority, under 35 U.S.C. § 119, of German application DE 10 2007 042 355.3, filed Sep. 6, 2007; the prior application is herewith incorporated by reference in its entirety.
The invention relates to a machine for processing printing material having at least one processing unit in which the printing material is modified in terms of shape or by applying a printing ink onto its surface. The printing material includes a surface area on which either an electrically conductive substance is present or onto which an electrically conductive substance is applied by an application unit of the machine for processing printing material. The invention furthermore relates to a method for operating the machine for processing printing material for structuring a surface area of the printing material on which either an electrically conductive substance is present or onto which an electrically conductive substance is applied by an application unit of the machine processing printing material. At least one processing unit of the machine for processing printing material modifies the printing material in terms of shape or by applying a printing ink onto its surface in the method.
Today, many printed products, in particular packaging or labels, are provided with data carriers such as electric circuits, for example radio frequency identification (RFID) tags, transponders, smart labels, memory elements, or chips as touch-free identifiers, for example to simplify logistics or to prevent crimes. In this context, efforts have been made to modify an electrically conductive substance on the printed product or printing material in a printing process in order to apply at least the antennae structures that are necessary for touch-free communication of the electric circuits with a read/readout device.
Ways to produce RFID labels in a printing process, in particular in a printing process using a printing plate (also referred to as a printing master) are described, for example, in international patent disclosure WO 2005/013189A2, corresponding to U.S. Patent Application Publication No. 2007/0039694 A1. Furthermore, published, non-prosecuted German patent application DE 10 2005 026 127 A1 discloses a sheet-fed printing press in which RFID transponders, in particular the antennae thereof, are applied to a printing material. In particular, the antennae are printed. One feature or characteristic of the RFID transponder, for example the shape of the electrically conductive paths, is examined in the machine, i.e. in line, just like the optical features of the entire printed product.
For certain applications, individualized electrical circuits are desirable, whereas multiplication processes such as a printing process using a printing master ideally produces identical copies. In accordance with one aspect of published, non-prosecuted German patent application DE 10 2005 002 150 A1, which describes the creation of memory elements in the form of printed sequences of conductive lines, create disruptions in the lines are created by mechanical, thermal, or preferably electrical devices. To simplify the disruption process, which is carried out by a read/write device applying a current, the individual lines have narrow points.
In typical printing processes, only structures of about 30 to 100 micrometers can be created in a reproducible way. The minimum structural size in offset printing, for example, is 20 micrometers. Consequently, only low frequencies of directly printed oscillating circuits can be achieved. Yet typical RFID applications require higher frequencies.
It is accordingly an object of the invention to provide a machine for processing printing material and a method for structuring the printing material which overcome the above-mentioned disadvantages of the prior art methods and devices of this general type, which enhances and/or broadens the options in terms of printing technology for printing material provided with a surface area with an electrically conductive substance.
In accordance with the invention, a machine for processing printing material contains at least one processing unit in which a printing material is modified in terms of shape or by applying a printing ink to its surface. The printing material includes at least one surface area on which either an electrically conductive substance is present or onto which an electrically conductive substance is applied by an application unit of the machine processing printing material. The machine according to the invention also contains a laser treatment unit for structuring the electrically conductive substance on the printing material by at least partially modifying or removing the electrically conductive substance by use of at least one focused laser beam of a laser.
The invention allows to structure printable electrical circuits or electronics, in particular polymeric electronics, or to structure printed blanks (or precursors) of electronic circuits or electronics by a laser in the machine for processing printing material, i.e. in line, in particular by post-treatment by a laser. Printed electric circuits, electronics, in particular polymeric electronics, or the blanks thereof are post-treated by a laser which partially modifies or removes the printed electrically conductive substance to obtain a fine-structuring or individualization, for example for RFID applications.
The surface area may have an unstructured geometric shape with straight or curved edges, or it may already have a structure, for example recesses, separations into sections, or inclusions, which do not bear any electrically conductive substance. The surface area may be simply connected. The electrically conductive substance may already represent an electric circuit.
In specific embodiments, in particular in inkjet printing, the printing ink may be inkjet ink. The electrically conductive substance may be an electrically conductive printing ink. The electrically conductive substance may be an individual substance or a compound of several different substances. The electrically conductive substance may be present on the printing material in particular after the action of the processing unit. The partial modification or removal may occur in a location-dependent or position-dependent way within the surface area. The printing material may in particular be paper, cardboard, paperboard, or organic polymer foil. The machine processing printing material may be a print shop machine. The laser light may in particular have a wavelength in the infrared spectral range, preferably between 800 nm and 1600 nm.
The surface area(s) with the electrically conductive substance may in particular be only surface parts of a printed packaging or of a label.
In a particularly advantageous way, in accordance with the invention, a laser can achieve structural sizes of less than 10 micrometers, in particular less than 5 micrometers, more particularly between 5 micrometers and 1 micrometer. Thus it is possible to create much finer structures than using conventional printing technology.
In accordance with a particularly preferred embodiment, the laser of the laser treatment unit in the machine processing printing material can be positioned relative to the printing material. In particular, the position of the laser and/or the position of the surface area of the electrically conductive substance may be detectable by a position detection unit and may be controllable by a control unit. In other words, the machine of the invention for processing printing material contains a register control for the laser treatment unit so that in-register, in-line treatment of the printed electrically conductive substance, in particular of the printed electronics, can be carried out by the laser(s).
The printing material may be transported along a transport path through the machine of the invention processing printing material by at least one transport device, for example transport drums in the case of sheet-shaped printing material or transport rollers in the case of web-shaped printing material. The laser treatment unit may be provided downstream of the processing unit along a path through the machine processing printing material.
In a first group of embodiments of the invention, the laser treatment unit of the machine processing printing material may contain a plurality of laser modules that are movable in the lateral direction relative to the transport direction of the printing material through the machine processing printing material.
In a second group of embodiments, the laser treatment unit of the machine for processing printing material may include a plurality of lasers whose light beams impinge on the printing material over the full used width in the lateral direction. In accordance with a slight modification, a laser treatment unit may include an arrangement that allows the use of a maximum width for electrical circuits, this maximum width being different than the maximum width of the color print. A further element of this group of embodiments is an arrangement in which further lasers are available to the left and right of the default or nominal position for the treatment so that the position can be changed by selecting the lasers to be used.
In accordance with advantageously refined embodiments, the laser treatment unit of the invention may include an autofocus for adjusting the focus position of the at least one laser beam. In this way, it is possible to specifically achieve a modification or removal in the depth of the electrically conductive substance present on the printing material. In particular, this provision allows targeted structuring of multilayer systems of electrically conductive substances.
Moreover, the machine of the invention for processing printing material may have the following features: the laser treatment unit may contain a plurality of individually controllable lasers. The laser(s) may be diode lasers, diode laser bars, solid-state lasers, or fiber lasers. The at least one laser may be a single-mode laser or a multimode laser.
The application unit for the electrically conductive substance may be a printing unit or a varnishing unit so that in particular the electrically conductive substance may be applied directly to the printing material. Alternatively, the application unit may be a dispenser or a labeling device, in particular if the electrically conductive substance is on a carrier that is attached to the printing material. In other words, the electric circuits or electronics, in particular polymer electronics, may be printed within the machine processing printing material in which the laser treatment is carried out, or they may be printed in a different machine prior to the production process so that the blanks are introduced into the machine processing printing material in which the laser treatment is carried out.
The electrically conductive substance may be a thermally sensitive (conductive) polymer. The polymer may be an organic polymer. The electrically conductive substance may be printable. To put it differently, before the application, the substance may be paste-like, fluid, or liquid. Alternatively, the electrically conductive substance may be on a carrier substrate, for example a polyester foil, or on an electronic chip. The electronic chip may be produced conventionally.
A first class of machines for processing printing material is formed by printing presses. In other words, the machine for processing printing material may be a printing press. In particular, the printing press may be a sheet-fed printing press, a rotary printing press, a multicolor printing press, an offset printing press, a flexographic printing press, a gravure press, or a combination printing press. In specific embodiments, the printing press may include at least one printing unit which can be converted between different printing processes from the group including offset printing, flexographic printing, gravure, serigraphy, xerography, ink drop printing (drop-on-demand inkjet printing), and letterpress printing. The printing press may be suitable or optimized for printing packaging. The machine processing printing material, in particular the printing press, may be a label printing machine. The label printing machine may be a web-fed printing machine for processing narrow webs.
A second class of machines of the invention for processing printing material is formed of machines for further processing (post press machines, machines for the further processing of prints, bookbindery machines). In other words, the machine for processing printing material may be a machine for further processing. In particular, the machine for further processing may be a folding machine, a saddle stitcher, a perfect binder, a thread sealing machine, a die-cutting machine, a piling machine, or a folder-gluer.
The inventive idea also encompasses a method carried out in a machine for processing printing material. The method of the invention in a machine for processing printing material is used or suitable for structuring a surface area of a printing material on which either an electrically conductive substance is present or onto which an electrically conductive substance is applied by an application unit of the machine for processing printing material. In accordance with the method of the invention, a printing material is modified by at least one processing unit of the machine for processing printing material in terms of its shape or by application of a printing ink onto the surface of the printing material. At least one focused laser beam of a laser of a laser treatment unit of the machine for processing printing material structures the electrically conductive substance by at least partial modification or removal of the electrically conductive substance.
The method of the invention in the machine for processing printing material can be used to produce a fine structure with dimensions of less than 6 micrometers. By the method of the invention, an antenna for a RFID transponder can be created as a result of the structuring. In an analogous way, it is possible to create structures that represent capacitances, inductances, transistors, or other electronic circuit elements.
In specific embodiments of the method of the invention, a three-dimensional structuring is carried out in superposed layers of electrically conductive substances by adjusting the focus position of the laser beam. In an advantageous embodiment of the method of the invention, the position of the laser and/or the location of the surface area with the electrically conductive substance may be detected by a position detection unit and controlled by a control unit.
A specific embodiment of the method of the invention refers to an individualization of printed electronics, electrical circuits, or the blanks thereof. A control unit controls the laser treatment unit in such a way that mutually different structures are created on individual surface areas of a plurality of surface areas carrying the electrically conductive substance on the printing material. Thus individual surface areas on the printing material are individualized for individual printed products in an irreversible and/or no longer manipulable way. Laser light causes an irreversible and/or no longer manipulable individualization of electronic circuits on printed products. Thus for example individualized RFID transponders or labels can be produced. Electronic circuits can be personalized. It is possible to introduce information on the date, a parts number, a serial number, a lot number, or the like.
The features of the machine of the invention for processing printing material and of the method of the invention in a machine for processing printing material which have been described herein may be implemented individually and independently of each other or in combination.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a machine for processing printing material and a method for structuring the printing material, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
Referring now to the figures of the drawing in detail and first, particularly, to
The four subsequent printing units 14 are used as application units 20. Each of these printing units 14 can apply a layer of an electrically conductive substance. The application may be based on a printing master or printing plate which is received on a plate cylinder 28 and is wetted with an electrically conductive substance. In a nip formed between a transfer cylinder 26 and an impression cylinder 24, the printed image of the electrically conductive substance is transferred to the printing material, which is transported on the impression cylinder 24. If the printing press 10 prints multiple copies (printed products per sheet) of packaging products onto one sheet, each copy is assigned at least one surface area carrying the electrically conductive substance. A laser treatment unit 22 whose laser light impinges on a sheet of printing material which is transported past the laser treatment unit 22 on the impression cylinder 24 is located downstream of each printing nip in the printing units 14 acting as an application unit 20. Once a layer of the electrically conductive substance has been applied, partial modification or removal may be carried out by the laser light that is focused on positions within the surface area. The partial modification or removal of the substance may be implemented by evaporation in surface parts of the surface area. In specific electrically conductive substances in the form of thermally sensitive polymers, the result of the thermal effect of the laser light may be that the electric properties of the polymer changes. In particular, the exposed areas of the polymer may become non-conductive, i.e. they may be turned into isolating areas. In a further application unit 20 following a first application unit 20, another layer of an electrically conductive substance may be applied onto the same surface area. The laser treatment unit 22 located downstream of the printing nip may then at least partly modify or remove this layer of the electrically conductive substance. Thus a multilayer, three-dimensional structure of an electrically conductive substance may be created on the printed product. In the example illustrated in
In typical applications of packaging or labels, printed electrical circuits generally only cover part of the surface that is to be printed with colored printing ink in a conventional process. For this reason, the laser treatment unit 22 may include a plurality of lasers, and the individual laser beams may be capable of being positioned in accordance with the arrangement of the printed electrical circuits, in accordance with the surface areas carrying an electrically conductive substance, in particular in accordance with the arrangement of the copies.
A position detection unit 30 is associated with each laser treatment unit 22. The position of the layers that have already been printed and/or the position of the treatment result of the laser exposure are detected. The position detection unit 30 may, for example, include a CCD array or a CMOS array as a sensor or detector. A control path is provided which can at least compensate for slow positional changes (slow as compared to the machine speed). The measured data are fed to a control unit 32. The control unit 32 activates the laser treatment units 22, in particular the positioning device of the laser treatment units 22, to provide a sufficient degree of register accuracy between the different layers of the electrically conductive substance and/or of the treatment patterns of the laser treatment unit 22. Furthermore, the process steps that have been carried out can be inspected. The register of the preceding color prints that have been carried out in the first four printing units 14 of the printing press 10 is likewise inspected and corrected if necessary.
As an alternative to the situation illustrated in
It is also possible to adjust a capacitance, in particular of an oscillating circuit, for accurate individual adaptation by a laser treatment. On the one hand, the area of the electrodes of the capacitance can be adjusted more accurately by the method of the invention than by direct printing. On the other hand, it is also possible to create the electrodes of a capacitor with multiple subareas and to adjust the capacitance to an accurate value by cutting off subareas.
In the case of transistors or similar electronic components, the process may be analogous. An additional aspect in this context is the three-dimensional character resulting from superposed layers. The circuit can be versioned or personalized by selective severing of connections or selective destruction of individual cells.
In accordance with the invention, the belt transport section of the saddle stitcher 52 contains the laser treatment unit 22 between the stitching station 52 and the trimmer 58, which in the embodiment of
| Number | Date | Country | Kind |
|---|---|---|---|
| 102007042355.3 | Sep 2007 | DE | national |
