Printing system for printing components

Abstract

The invention relates to a printing system (2) for a component (4) with a printing device (8) for applying a marking (6) to the component (4). The printing device (8) has pad printing means (10) for applying an ink mass (11) to a marking surface (24) of the component (4) for the marking (6) and is equipped with a feed device (12) which has conveyor means (14) and feeds the component (4) to the printing device (8) by means of the conveyor means (14), and with an irradiation device (16) arranged downstream of the printing device (8), wherein the irradiation device (16) has a radiation source (18) for generating NIR radiation (20) for drying the ink mass (11) applied to the component (4).The irradiation device (16) is set up and designed such that the radiation source (18) generates at least one radiation field (22) for irradiating the component (4), wherein the NIR radiation (20) acts directly on the component (4), in particular on the marking surface (24), preferably on the ink mass (11) applied to the marking surface (24). Furthermore, the invention also comprises a respective pad printing method for applying a marking to a marking surface (24) of a component (4) using a printing system (2) of the aforementioned type.

Description

The invention relates to a printing system for printing a component with a coloring composition.In the industrial printing of components, printing systems of different designs are known which are integrated in a production process or are part of the production of a component.Printing systems of the relevant type thus serve, for example and in particular, for applying an identification to a component for its labeling or identification. Increased requirements are placed on this, since the marking is not only via a flat application of ink, but in particular by applying characters, such as letters, numbers, symbols, bar / bar codes, as well as QR codes and the like. The characters can also be used for inscription of a component with information of any desired type.There is, for example and in particular, the requirement for a printing system of the relevant type to apply such characters with sharp contours to a component and thus to ensure reliable sensoric or machine recognition or detection of such a characteristic. This is intended to avoid misrecognition of a character which has different consequences depending on the use. In particular in sensitive areas in which electrical or electronic components are used, labels incorrectly applied to a component are undesirable and therefore to be avoided. Accordingly, misprinted components ensure that these components are rejected.The demand for the application of a label is increasing with the purpose and field of application for which a label is intended. For example, increased requirements are placed on identifiers of electrical and electronic components, since the identifiers can comprise, for example, type specifications and also further specification specifications which are important and decisive for their safe use.Furthermore, a further requirement for application is that the marking has appropriate durability and is adapted for the respective field of application in order to be able to prevent damage to the marking even in adverse environmental conditions.In the context of industrial printing of components, there are various methods and devices or printing systems. The screen printing method and the pad printing method have proven to be particularly suitable. In particular for printing small-area or uneven surfaces, the pad printing method has proven to be particularly suitable, so that it is widely used, among other things, in the printing of housings of electrical or electronic devices.The pad printing method is an indirect gravure printing method in which an ink composition is transferred by means of an elastic stamp, the so-called pad, from a print image carrier, the so-called plate, to the component for its identification.For this printing process, the print image carrier has a surface which is provided with a print image for representing the marking. The printed image can be produced, for example, in the case of a cliché made of a metal material by a etching method, so that the surface has depressions for a contour which represents the marking. The cliché can also be formed by other materials, so that the contour is also created using other already known methods.An ink composition is applied to the printing plate by means of a so-called doctor blade in such a way that it remains in the depressions of the surface. The indicia is applied to the component by the pad receiving at least a portion of the ink composition in the recesses and transferring it to the component by pressing the pad onto one surface thereof.Accordingly, printing systems of the relevant type have a printing device for applying a marking to a marking surface of the component provided for this purpose, wherein the printing device has pad printing means which are designed and designed for applying a coloring compound to the component for marking it.The application takes place according to the pad printing method described above, so that the pad printing means comprise the further components, such as, for example and in particular, a plate, an ink mass supply, means for applying ink mass to the plate, a pad for removing the printed image from the plate and applying the printed image as a marking to the component, a doctor blade and the like, and which are correspondingly configured and formed.The components of the pad printing means are already known from the prior art in different designs, designs and configurations. These can therefore be derived from the already known prior art.For automated or at least partially automated printing, printing systems of the relevant type have a feed device with conveying means which are designed and designed to feed the component to the printing device in order to print it by the printing device.The supply device can moreover be configured and configured in such a way that the component is removed from the printing device after it has been printed and transported further.The conveying means of the feed device can be formed, for example, by a handling device or a robot, a continuous as well as an discontinuous conveyor, in particular a belt or chain conveyor, and the like. For this purpose, various possible implementations are already known from the prior art and are also widely used and proven, so that a further detail can be derived from the prior art.The feed device serves the purpose of feeding the component to be printed to the printing device in such a way that the latter can be provided with a marking. The label is applied by the pad printing means in the aforementioned manner. For this purpose, the component is to be oriented accordingly. This is preferably done by means of the supply device, which supplies the component to the printing device in a predetermined orientation. This can be effected in particular by carriers for the component which are set up for this purpose, and also by controlling the feed device, for example a manipulator or a robot.Printing systems of the relevant type are moreover also equipped with an irradiation device downstream of the printing device in a process, wherein the irradiation device has a radiation source for generating a near-infrared radiation, also referred to below as NIR radiation, for drying the ink composition applied to the component.The term "process" in this context relates to the time sequence determined by the application of a marking to the component, so that in particular the ink composition is to be applied to the component first before it is dried. In this respect, the actions in question take place in a corresponding sequence.For drying the ink composition, it is known from the prior art to use NIR radiation in order to dry the component with the ink composition applied thereto by heated ambient air. Therefore, the NIR radiation is used to correspondingly heat the ambient air and bring it to a temperature level in order to achieve the fastest possible drying of the ink composition and to prevent the ink composition from running out. For this purpose, measures are known accordingly from the prior art in order to keep the ambient air available accordingly. This is effected, for example and in particular, by means of a drying or heating channel into which the component is introduced or passed through it, so that the ink composition dries in the drying channel.Known printing systems of the relevant type provide for the irradiation device to have a radiation source for generating an NIR radiation for drying the ink composition applied to the component.The energy consumption for operating a relevant printing system of the known type is high, since, for example, the systems must first be brought into a corresponding operating state to form a sufficient heat environment for drying the ink composition. Furthermore, heat escapes to a relevant printing system during its operation, which heat must be correspondingly supplied again in order to be able to carry out the necessary drying.Therefore, the object of the invention is to optimize the energy requirement of a relevant printing system.The invention is based on the idea of changing the radiation source and using an alternative radiation. The invention further moves away from the approach of achieving an improvement in the energy requirement by means of improved thermal insulation.The invention achieves the object in a surprising manner while eliminating an increase in the equipment requirement, in that the NIR radiation of the radiation source is directed according to the invention onto the component in such a way that the radiation acts directly on the ink composition applied to the component by a radiation input of the NIR radiation.For this purpose, the invention provides that the irradiation device is configured and designed in such a way that the radiation source generates at least one radiation field for irradiating the component, wherein the NIR radiation acts directly on the component, in particular on the identification surface, preferably on the color mass applied on the identification surface.This alignment according to the invention advantageously results in an efficient use of the NIR radiation for drying the ink composition.In the context of the invention, a wavelength of the NIR radiation in a value spectrum between 0.75-1.2 micrometers can be used.The invention thus achieves the advantage that the NIR radiation is not used indirectly for drying via the heating of the ambient air, but rather the radiation acts directly on the color composition.The invention makes it possible to introduce the NIR radiation directly into the ink composition and to use the radiation energy in such a way that the ink composition brings about dehumidifying or drying of the ink composition from a layer close to the component to a layer remote from the component.The ink composition is thus dried from an inner layer in the direction of an outer layer of the ink composition by the NIR radiation passing through a liquid layer and first drying a layer close to the component.The ink composition is therefore gradually dried from the inside to the outside according to the invention, so that drying-related surface cracks on the ink composition are avoided. The invention is thereby dependent on the approach of first heating the ambient air by means of NIR radiation or of producing a temperature level of the ambient air surrounding the component for drying the ink composition applied thereto. Thus, according to the invention, the effect of the NIR radiation is generated directly on the ink composition, whereby the drying sequence of the ink composition advantageously reverses compared to the prior art and advantages in the identification quality arise with the aid of the invention.In this context, a direct action in the context of the invention means that the NIR radiation does not indirectly heat the ambient air and use it to dry the ink composition, but rather the radiation itself acts on the ink composition and, by introducing the NIR radiation into the ink composition, brings about a drying of the ink composition from an inner layer of the ink composition toward an outer layer of the ink composition. An inner layer of the ink composition is therefore adjacent to the marking surface opposite an outer layer.According to the invention, the drying of the ink composition is achieved by the moisture being conducted outwards from the interior of the ink composition via still liquid layers, since these dry successively and thus subsequently to one another in time. As a result, the invention advantageously realizes a high printing and identification quality, which is decisive for an industrial printing of a component. The process can thus advantageously be partially automated as well as fully automated.Furthermore, heat-insulating measures and devices are not required by the invention. In contrast to the known drying devices and methods, the invention makes it unnecessary to use a heat channel through which the component is carried out and in the process the ink composition is dehumidified or dried by means of the ambient air heated by the NIR radiation.The drying time is significantly reduced with the aid of the invention compared to known printing systems, whereby printing is fixed more quickly and imaging errors are thus avoided, which can be caused, for example, by air currents for generating a thermal environment for drying the ink composition. This in turn results in manufacturing and handling advantages, so that, in addition to cost savings, the products can be used more quickly.Furthermore, the temperature in a heat channel does not have to be monitored and the heat supply for a temperature profile does not have to be regulated. This results in further cost advantages due to the possible saving of temperature monitoring. Furthermore, this entails simplified process control for the drying, which contribute to lower waste due to components that are incorrectly marked.In addition, the invention makes it possible to minimize the waste of incorrectly printed components caused by a lack of print quality.For this purpose, the invention provides that the irradiation device is configured and designed in such a way that the radiation source generates a radiation field which is directed directly onto the component supplied to the printing device by the supply device, in particular onto the ink mass applied to the component.In a further advantageous development of the invention, it is determined that the radiation field is directed directly onto the component, in particular onto the identification surface.The efficiency of a printing system according to the invention is thus increased in that the NIR radiation is directed directly onto the component or the marking surface and therefore losses of action are avoided, which can be caused, for example, by measures for deflecting the NIR radiation. Therefore, the NIR radiation can pass from the radiation source directly onto the component or the marking surface, so that efficient drying of the ink composition is achieved.In order to further reduce the energy requirement, it is determined in a further advantageous development of the invention that the irradiation device has a control element which is designed and designed in such a way that it cycles the irradiation of the component, in particular of the color mass applied to the marking surface, with NIR radiation by means of an adjustable or preset irradiation duration.The invention thus achieves the advantage that the amount of radiation for the component or the marking surface can be matched to the respective ink composition and therefore the NIR radiation can now be adjusted or metered in this way with respect to the radiation energy required for drying. For this purpose, the irradiation duration is adjusted accordingly and the irradiation is controlled or regulated accordingly.Within the scope of the invention, the term "control" also encompasses the features of "regulation". Accordingly, a controller also includes a feedback control.According to the invention, this can be achieved in various ways, for example by means of a mechanical shield, for example via a radiation barrier which is correspondingly temporarily introduced between the radiation source and the component.It has been found within the scope of the invention that the irradiation time can be kept within very narrow time windows which are sufficient for drying the ink composition. Accordingly, it is taken into account according to the invention that the irradiation means are configured and configured such that the radiation source performs irradiation of the component with a variably adjustable or predetermined irradiation duration which lies in a small second duration range. This achieves a further energy saving in that the radiation means generate NIR radiation discontinuously.For this purpose, the further development of the invention provides that the control element cycles the irradiation duration with a time value between 0.4 and 1.2 seconds, preferably between 0.5 and 0.7 seconds, most preferably with 0.6 seconds.The invention thus achieves the effect that the irradiation can be adjusted to the marking applied to the component and the amount of radiation or the introduction of radiation energy into the ink composition can likewise be determined or is determined over the irradiation duration. Furthermore, the necessary energy can thus be reduced to a minimum, so that the energy requirement can thus be correspondingly reduced.In addition, a short irradiation duration ensures that no burning of the components or of the paint mass applied thereon occurs due to the NIR radiation and waste heat arising therewithThe means required for this can be reduced to a minimum, so that the invention provides for the radiation source to be switched on or off accordingly in order to be able to dose the NIR radiation accordingly.In a further advantageous development of the invention, it is intended for the control element to actuate the irradiation device in a control-related operative connection with the irradiation device in such a way that the irradiation device changes between an active state, in which it generates the NIR radiation for the radiation field, and an inactive state, in which the radiation source is deactivated.The operatively connected control connection serves to switch the irradiation device, in particular the radiation source, in such a way that NIR radiation reaches the component or the identification surface and thereby irradiation of the component or the identification takes place and furthermore switches the radiation source in such a way that an aforementioned irradiation of the component or the identification surface with NIR radiation is omitted. This reaches the control member by controlling the irradiation device to switch the radiation source on or off. For this purpose, the radiation element sets the irradiation device into an active state in which the NIR radiation is available for irradiating the component or the identification surface. Furthermore, the radiation element sets the irradiation device into an inactive state in which no NIR radiation is available for irradiating the component or the identification surface.For this purpose, the radiation element can be realized by an electrical or electronic control device which is connected to the radiation device by signal technology for a corresponding switching and controls or regulates the radiation device accordingly.As already mentioned above, within the scope of the invention, a control also comprises a regulation for assuming the aforementioned states by the irradiation device. In a simple manner, a change between an active state and an inactive state of the irradiation device can be achieved in such a way that the radiation source is switched on or off. For this purpose, the current supply for the radiation source can be switched accordingly.Furthermore, a further increase in the energy saving is advantageously achieved within the scope of the invention in that the radiation source is configured and configured such that the irradiation of the color mass is synchronized with the feeding of the component by the feeding device and, when the component is fed, enters an active region of the radiation source and begins the irradiation for the component in that the radiation source generates the radiation field.Accordingly, in a corresponding development of the invention, it is determined that the control element tunes the irradiation duration with the feeding of the component by the feeding device and synchronizes irradiation by the radiation source with an entry of the component into an effective range determined by the radiation field.Within the scope of the invention, the range of action is determined by the radiation field in which the radiation realizes its drying or liquid-withdrawing action on the ink composition. The effective range therefore determines according to the invention the region in which the component enters and in an active state of the irradiation device the NIR radiation acts on the component for drying the ink composition. According to the invention, the active region can be congruent with the radiation field, for example and in particular. According to the invention, the radiation field can also be larger than the effective range, wherein the difference is a range of the larger field which shows no or only a negligible drying effect on the applied ink composition.In this way, in addition to saving energy for operating the irradiation device for drying the ink composition, targeted drying of the ink composition applied to the respective component can also be achieved. Furthermore, it is thereby possible to keep the energy input for drying the ink composition low. In addition, this ensures that the drying takes place very precisely.Furthermore, it is achieved that the NIR radiation acts on the components only when it reaches the active region or the radiation field of the radiation source. This prevents the dye composition from drying too quickly as a result of NIR radiation applied too long in time or from causing damage to the marking. This is achieved according to the invention by introducing energy of the NIR radiation into the ink composition, which energy is matched in time and thus effected efficiently with the supply of the components.This can be achieved in a simple manner, for example and in particular, by the conveying means having a drive for conveying the component, which is controlled via a sensor between an active state, in which the drive for conveying the component is activated, and an inactive state, in which the drive for conveying the component is deactivated.Alternatively as well as additionally, a previously described synchronization of the irradiation duration can be achieved in that the radiation source is switched between an active and an inactive state in a control-related operative connection with the feed device or the conveying means. The states have already been described above, so that repetition is omitted at this point and reference is made to the aforementioned.An aforementioned sensor can be realized, for example, in a simple manner by means of a light barrier or a plurality of light barriers which detect a passage of the light barriers through the component in a contactless manner and are therefore arranged at a distance from one another on the path of the component along which the component is supplied to the printing device and removed therefrom in such a way that, in particular, the irradiation duration can be controlled or regulated therewith.Depending on the configuration of the path, a light barrier or a sensor is sufficient in the simplest case. For this purpose, there are many possibilities for configuring a sensor which is capable of detecting a passing or a movement of the component.According to the invention, sensor means can serve for this purpose, which are set up and designed for synchronizing the irradiation device with the feed device and are connected for this purpose with the irradiation and feed device in terms of regulation or control technology and are consequently brought into an operative connection in terms of control technology.For a precise irradiation of the color mass applied to the component for the desired marking, it is determined in a further advantageous development of the invention that the radiation source for irradiating the component is arranged in a vicinity thereto, in particular at a distance of less than 15 cm, preferably less than 10 cm, most preferably less than 8 cm.Within the scope of the invention, it is included that the distance is adjustable or set in a correlating manner with the color mass or irradiation duration. Advantageously, this ensures that the energy input into the ink composition can be carried out in a targeted manner and that the amount of scattered radiation which does not enter the ink composition is kept low. Furthermore, the power of the radiation source can thus also be selected to be correspondingly adapted, so that the invention thus contributes to a further energy saving.Taking this approach, in a further advantageous refinement of the invention, it is provided that the radiation source is designed and designed such that its electrical energy requirement is less than 2.9 kilowatts, preferably less than 2.5 kilowatts, preferably at 2.1 kilowatts.The invention thus realizes that the necessary electrical energy for the irradiation of the component can be conducted to a reduced energy level. This also makes it possible to achieve the effect that the irradiation intensity can be adjusted to a level which keeps unnecessary irradiation of regions adjacent to the marking of the component low.In order to further specifically dry the coloring material and to concentrate the NIR radiation accordingly on the coloring material, it is provided in a further advantageous development of the invention that the irradiation device have a limiting element which is configured and designed to limit a radiation field of the NIR radiation.According to the invention, it is thus achieved that the radiation field of the radiation means is limited and that the radiation is thus prevented from reaching, in an undesired manner, surrounding regions or further components, the color mass of which is initially intended to remain unexposed by the radiation means. This effectively prevents a coloring compound applied to the component from being irradiated in an uncontrolled manner and thus damage or destroy the marking produced on the component by an unnecessary input of energy.For this purpose, in a further advantageous development of the invention, it is provided that the delimiting element has at least one delimiting body which is configured and designed for delimiting the radiation field in a first spatial direction and a second spatial direction, in particular is designed in the manner of a pinhole diaphragm and / or slit diaphragm and / or a radiation screen.This makes it possible to easily avoid undesired damage to a component. Furthermore, this ensures that the marking is formed by the ink composition with the required quality.For this purpose, the invention provides that the delimiting element is introduced between the radiation source and the component at least during the irradiation of the component or the identification surface by the NIR radiation. In this respect, the delimiting element is arranged downstream of the radiation source in particular in a radiation direction of the NIR radiation and can thus bring about a corresponding planar delimitation of the NIR radiation. In this case, it is provided, for example and in particular, that the first and second spatial directions are each aligned transversely to the radiation direction and in particular also transversely or orthogonally to one another.Within the scope of the invention, the radiation limiting element can achieve a limitation of the radiation field in a mechanical manner by providing, for example, a limiting body configured as a diaphragm, which is introduced in a radiation direction of the NIR radiation source, in which the NIR radiation source emits the NIR radiation for irradiation of the component. For this purpose, the diaphragm body can be designed, for example and in particular, as a perforated or slotted diaphragm. Furthermore, it is possible to form the aperture body by means of a plate which is designed to delimit the radiation field, for example has bent sections, by the arrangement and design of which a delimitation of the radiation field can be realized or is realized.Accordingly, in an advantageous development of the invention which is linked thereto, it is provided that the radiation limiting element has at least one pinhole stop and / or slit stop and / or a radiation screen which is / are arranged downstream of the radiation source in the radiation direction of the NIR radiation.Advantageously, the radiation field of the NIR radiation can thus be limited in a simple and cost-effective manner. Furthermore, it is thus possible for the radiation field to be correspondingly easily adjustable. Moreover, it is achieved that the parts surrounding the radiation source are not inadvertently exposed to NIR radiation. In addition, a safety measure for the work protection can thus be realized in a simple manner.Within the scope of the invention, different coloring masses can be used for applying a marking to the component.In the context of the invention, a dye composition can comprise, or be formed from, an ink carrier, a dye, optionally a hardener, a diluent, optionally a retardant, and also optionally further additives.For application of a marking to a component or printing of the component, the adhesion properties, the consistency and the curing features of the ink composition are embossing.A curing agent influences the processing and curing of the ink composition and also the resulting properties of the coating, such as the covering quality and the mechanical strength or the hardness of the ink composition or marking applied to the component by pad printing.The composition of hardeners frequently uses diisocyanate, which is a highly reactive compound. The hardener helps conventional paint compositions dry in a shorter period of time and form a sufficiently durable outer layer.A conventional ink composition is often processable for a limited number of hours with a sufficient viscosity and usable for pad printing. This processing time is also known as the drip time.However, this pot life is reduced when hardeners are used and leads to the ink composition being usable only for a few hours. Often the pot life is less than 8 hours. The ink containers in which the ink composition is available for use must thus be cleaned, wherein the ink composition remaining in the ink container must also be disposed of. This is associated with corresponding time and energy costs for the cleaning.In pad printing, there are high requirements for the ink composition so that it can be transferred from the printing plate to the pad and from the pad (almost) completely to the target surface. This presents particular challenges regarding the printing process on the adhesion / drying properties, so that unfavourable constellations ensure unsuitable ink transfer. Therefore, the abovementioned ink compositions without curing agents have not been used, or have scarcely been used, since they are not "adjustable" or are more difficult to adjust accordingly to the pad print in order to achieve the required quality of display of the marking.In a further advantageous development of the invention, it is therefore provided to dispense with the use of a hardener in the ink composition. This leads to a prolonged processing capacity and usability of the ink composition for pad printing.The invention also provides an advantage of protecting health and environment, since the active ingredients of the hardener are suspected of causing cancer in the human body. In addition, the absence of the hardener can leave the action of a retarder unaffected.Furthermore, it is also provided within the scope of the invention to use a coloring compound that is free of silicone. This advantageously ensures that the ink can be applied to the component in a production-safe manner. In addition, the ink composition is also flexible after it has dried, and so-called silicone transfer is prevented, which undesirably adversely affects the identification and, if appropriate, the component.Therefore, in a further advantageous development of the invention, it is provided that the coloring compound is free of curing agent and / or free of silicone.In order to improve the processability according to the invention, it is provided in a further advantageous development of the invention that the ink composition has a retardant.A retardant serves as an additive to an ink composition to adjust the desired viscosity of the ink composition and also to extend the time until the ink composition cures. This increases the processability for pad printing, so that the invention thus likewise leads to the advantages already mentioned.The use of a retarder advantageously helps to increase the display quality of the marking after application of the ink composition to the component, so that the marking can be applied to the component in a sharply contoured manner according to the invention. The composition of the retarder makes it possible to set the quality of the display in accordance with the requirements placed in each case.Retarders are volatile, among other things, whereby the ink composition cures with increasing escape of the retarder from the ink composition. For this purpose, the invention achieves the advantage that the retarder can escape by the NIR radiation by a directed drying / dehumidifying of the ink composition without damaging the marking surface.This is achieved by drying the coloring composition by means of irradiation according to the invention from the inside to the outside. The invention thus achieves a corresponding surface quality of the marking, which enables reliable sensory or machine recognizability.As described above, a printing system according to the invention is designed and configured to print a surface of components and thus to apply an identification to the component. The invention also makes it possible to print unfavorable surfaces for printing.For this purpose, in an advantageous development of the invention, it is determined that a printing system according to the invention comprises at least one component to be marked, wherein at least the marking surface, in particular a housing of the component on which the marking surface is arranged, is formed at least in sections from a plastic, in particular from a polyamide, or has a plastic, in particular a polyamide, and wherein in particular the marking surface is formed at least in sections• a roughness having a mean roughness value Ra {according to DIN EN ISO 4287:2010 in the current version of the guideline} low VDI 21 or (as well as and / or)• a surface energy of less than / equal to 42 mN / m or.• A surface humidity of greater than or equal to 2 mass percent has. The aforementioned values apply in particular before printing or application of a coloring composition to the marking surface.The acronym VDI stands for the German Engineer Verein e.V. (VDI Verein Deutscher Engineer e.V.), the services of which include, inter alia, the creation and publication of guidelines for various technical areas.The invention makes it possible to reduce the surface roughness class, so that comparatively smooth surfaces can now also be printed, which previously provided imaging errors that are unacceptable for the identification of electrical / electronic devices and therefore cause waste. Accordingly, the invention also contributes to sustainability in that waste caused by printing is avoided or reduced. According to the invention, the requirements for the roughness are significantly reduced.Surface energy is important for wettability of surfaces. This energy is decisive for a sharp-contour printing or marking of the component. By virtue of the invention, secondary effects of the labeling adhesion can likewise lead to a more contour-enhanced labeling, since the color does not run "over time" (this effect is also referred to as dewetting), but rather, by virtue of rapid drying according to the invention, leads to a labeling stability, as is desired for application of the color by the tampon.Moist components and associated wet surfaces or labeling surfaces are pre-treated according to the prior art for printing or applying a coloring compound. This is conventionally achieved by drying and plasma treatment, so that the moisture value for the printing is reduced to a corresponding extent and the surface energy is increased in order to make the surface more hydrophilic. According to the invention, such a pretreatment can likewise be dispensed with, so that the time, effort, cost and energy requirement can thus be correspondingly advantageously reduced.As already mentioned, the invention contributes to the omission of a further heat after-treatment of the components to which a marking is applied by means of pad printing. Conventionally, relevant components are post-treated, for example, in a tempering furnace by tempering in a separate process or in concatenation by a heat tunnel, which can now be dispensed with according to the invention.The invention advantageously also achieves a high-quality printing or marking of the component under adverse conditions which are determined by the component. This makes it possible to dispense with special measures for conditioning the component for printing it. The invention thus achieves further energy, effort and cost savings.Within the scope of the invention, the invention comprises in particular a printing of components in a series process, so that a correspondingly economic application of a marking to components by means of the printing system according to the invention is achieved therewith.According to the invention, the component is, for example and in particular, an electronics housing which serves for the housing of at least one electrical and or electronic component. The relevant electronics housing can be printed by a printing system according to the invention in a partially or unequipped state as well as in a populated state.The invention also includes a pad printing method for applying a marking to a marking surface of a component with a printing system, which is formed in particular as described above,• in which, in a first step, the component is supplied to a printing device by means of a supply device, and• wherein, in a second step, the marking is produced by applying a coloring composition to a marking surface of the component by pad printing means of the printing device,• Wherein, in a third step downstream of the second step, the identification surface of the component to which the ink composition is applied is irradiated with an NIR radiation by an irradiation device.A pad printing method according to the invention is characterized in that the irradiation device is configured and designed such that the identification surface of the component supplied to the printing device by the supply device is irradiated directly by means of the NIR radiation generated by the radiation source.A pad printing method according to the invention thus leads to the advantages as already explained with reference to a printing system according to the invention. For this purpose, the aforementioned characteristics and features of a printing system according to the invention can also be used for a pad printing method according to the invention and can be transferred accordingly. Therefore, the relevant explanations also apply accordingly to a pad printing method according to the invention, so that instead of a repetition reference is made to the previously described explanations.In this respect, a pad printing method according to the invention can use the following options, which advantageously develop such a pad printing method in an isolated manner or in any combination, such that optionally in particular the irradiation of the component, in particular of the color mass applied to the marking surface, is clocked with NIR radiation by a preset irradiation duration, or optionally in particular the irradiation duration is preset with a time value between 0.4 to 1.2 seconds, preferably between 0.5 to 0.7 seconds, most preferably with 0.6 seconds, or optionally in particular the irradiation duration is synchronized with an entry of the component into an active region determined by the radiation field or optionally in particular a radiation source for irradiating the component is provided, which is arranged in a close range to the component, in particular to the marking surface, in particular at a distance from the component, in particular to the marking surface, less than 15 cm, preferably less than 10 cm, most preferably less than 8 cm, or optionally in particular the radiation source is configured and configured such that its electrical energy requirement is less than 2.9 kilowatts, preferably less than 2.5 kilowatts, preferably at 2.1 kilowatts, or optionally in particular the NIR radiation is limited by at least one limiting element, or optionally a component is printed in which at least the identification surface, in particular a housing of the component on which the identification surface is arranged, is formed at least in sections from a plastic, in particular from a polyamide, or comprises a plastic, in particular a polyamide, or optionally in particular wherein the identification surface is printed at least in sections• optionally a roughness with a mean roughness value Ra according to Guideline VDI 3400 in the current version} of low VDI 21 or (as well as and / or)• optionally a surface energy of less than or equal to 42 mN / m or (as well as and / or)• optionally a surface humidity of greater than or equal to 2 mass percent wherein the aforementioned values apply in particular before printing or applying the coloring composition.A printing system or pad printing method designed according to the invention results, among other things, in the fact that different pre- and post-treatment steps can be dispensed with. Furthermore, the invention ensures that the ink composition applied to the component or the identification surface is cured within a significantly small time window and, for example and in particular, within about 30 seconds and can thus be used accordingly.According to the invention, it is furthermore possible for the ink composition to have an excellent service life / pot life and therefore to be usable over a long period of time, in particular 72 hours or up to 96 hours.This means that the ink composition can be used for an extremely long time compared with conventional ink compositions without having to be post-thinned, with at the same time significantly accelerated curing by the NIR radiation used according to the invention.In addition, the invention makes it possible to use a coloring composition with high hiding power due to a high pigment content (so-called highly pigmented color) for applying a marking to a component.The invention is explained in more detail below with reference to the attached drawing, in which an exemplary embodiment is shown as representative of a plurality of variants of a printing system according to the invention or of a pad printing method according to the invention, with reference to which an embodiment is made clear which concerns the invention with respect to a printing system as well as a pad printing method.In this case, the corresponding steps or features can be derived from the figures to clarify tampon printing methods according to the invention.All the features claimed, described and shown in the drawing form the subject matter of the invention on their own and in any combination with one another, independently of their references and independently of their description or representation in the drawing.Therefore, the features are not tied to the constellation explained below, but rather can also form a printing system according to the invention or a relevant pad printing method in an isolated manner from one another and also in a different compilation or constellations.The figures of the drawing show the aforementioned embodiment of a printing system according to the invention in schematic representations in each case.The representations in the figures are therefore not necessarily true to scale, so that, among other things, the scales selected in each case in the figures can also be different from one another.For better clarity, the representations are reduced to the elements / components / components supporting understanding.In the figures, identical or corresponding components / components or elements are provided with the same reference numerals.For the sake of better clarity, not all elements / components / components are always provided with reference symbols in the figures, wherein the assignment is obtained by the same illustration or an illustration adapted to the view.It shows: FIG. 1 shows a first exemplary embodiment of a printing system according to the invention for a component of a side view in a schematic representation, in a first printing state, in which components are provided with a marking; FIG. 2 shows the first exemplary embodiment of a printing system according to the invention from FIG. 1 in the same side view and in a schematic representation, in a second printing state, in which components are irradiated with NIR radiation; FIG. 3 shows a second exemplary embodiment of a printing system according to the invention in a side view which is analogous to FIG. 1 but has a reduced detail, and also in a schematic illustration, in a second printing state in which components are irradiated with NIR radiation; FIG. 4 shows a third exemplary embodiment of a printing system according to the invention in a side view and manner of illustration analogous to FIG. 3, in a second printing state, in which components are irradiated with NIR radiation.FIG. 1 shows the first exemplary embodiment of a printing system 2 according to the invention for a component 4, which is illustrated in a side view in a schematic representation. The components 4 are each shown symbolically in the figures with a diamond and, for better clarity, are provided once with the reference symbol 4 on one of these diamonds. The components 4 need not be of uniform design according to the invention, but rather can be designed differently from one another in particular in the form of the respective housing 5 (excellent once in FIG. 1 ).The first exemplary embodiment of a printing system 2 according to the invention is also referred to below for short as a printing system 2.In FIG. 1, the printing system 2 is shown in a first printing state, in which a first set 4' of components 4 is provided with a respective marking 6. The respective markings 6 are uniformly provided with the reference sign 6 in the figures.The respective marking 6 is applied according to the invention to the respective component 4 by means of printing.For this purpose, a printing device 8 is provided, which has pad printing means 10 for applying a coloring compound 11 to an identification surface 24 of the component 4 for the identification 6.The printing device 8 can be configured and designed independently of the respective constellation according to the invention of an exemplary embodiment according to the invention in such a way as to apply different markings 6 to the components 4. Therefore, the markings 6 do not necessarily have to be of uniform design according to the invention. Furthermore, the printing device 8 can be configured and designed independently of the respective constellation according to the invention of an exemplary embodiment according to the invention of a printing system 2 in such a way that a plurality of markings 6 are applied to one or different components 4 in one process.The printing system 2 is equipped with a feed device 12 which has conveying means 14 for feeding the respective component 4 to the printing device 8. The conveying means 14 can be realized in different ways, wherein in this example conveyor belts 14' are symbolically represented as one of many possible realizations, which are driven by a drive (not shown). The drive (not shown) is controlled via a controller. Furthermore, an irradiation device 16 is provided which is arranged downstream of the printing device 8 in a process, wherein the irradiation device 16 has a radiation source 18 for generating an NIR radiation 20 (illustrated in FIG. 2 ) for drying the ink mass 11' applied to the component 4 (marked once in FIG. 1 ).The irradiation device 16 is configured and configured in such a way that the radiation source 18 generates at least one radiation field 22 for irradiating the component 4, wherein the NIR radiation 20 (visible in FIG. 2 ) acts directly on the component 4 and, in this example, directly on the provided identification surface 24 provided for the identification 6 (marked once in FIG. 1 ).In this exemplary embodiment, the NIR radiation 20 (see FIG. 2 ) acts directly on the color mass 11' applied to the marking surface 24, since this is not covered by an element such as a transparent cover.It can be seen from FIG. 1 that in the printing system 2 shown, the irradiation device 16 is configured and designed such that the radiation field 22 is directed directly onto the relevant component 4 or its identification surface 24.In order to be able to apply the irradiation reliably to the marking surface 24, the irradiation device 16 has a control element 26 which is designed and designed in such a way that it cycles the above-described irradiation of the relevant component 4 with NIR radiation 20 by means of a preset irradiation duration. For this purpose, it is provided that the control element 26 cycles the irradiation duration with a time value between 0.4 and 1.2 seconds, wherein the control element 26 allows the time value to be set and varied according to the respective conditions. This may be done automatically by sensing and evaluating various parameters by sensors 28 to determine the timing values accordingly. This can preferably take place in the process context, so that no process interruption is necessary for such a setting.In FIG. 1, representative of a plurality of different types of sensors 28, which can be used individually, multiple times as well as in combination with further sensors 28 in a printing system 2 according to the invention, a proximity sensor 28' is shown, which serves to detect the approximation of a component 4 or of a plurality of components 4 or a set of components 4' and signal the control element 26 for the initiation of further operations.For this purpose, the proximity sensor 28' is connected to the control element 26 by signal technology, which can be effected for example and in particular via a control line 30. Thus, the proximity sensor 28' and the control member 26 are operatively connected to each other in terms of control technology.Furthermore, it is provided that the control element 26 controls the irradiation device 16 in a control-related operative connection with the irradiation device 16 in such a way that the irradiation device 16 changes between an active state (shown in FIG. 2 ) in which it generates the NIR radiation 20 for the radiation field 22 and an inactive state in which the radiation source 18 is deactivated and in this state does not irradiate the component 4 with NIR radiation 20.According to the invention, it is also provided in this printing system 2 that the control element 26 tunes the irradiation duration with the feeding of the component 4 by the feeding device 12 and synchronizes irradiation by the radiation source 18 with an entry of the component 4 into an effective area 32 determined by the radiation field 22. In this printing system 2, components 4 are fed to the irradiation device 16 in a bundled manner, so that the temporally first and the temporally last component 4 of a set of components 4', which is fed to the irradiation device 16, determine the aforementioned change between the active and passive states.For a good drying of the ink composition 11' applied for the marking 6 of the component 4, it is provided according to the invention that the radiation source 18 for irradiating the component 4 is arranged in a vicinity to the component 4, in particular to the marking surface 24, in particular at a distance from the component 4, in particular to the marking surface 24, less than 15 cm, preferably less than 10 cm, most preferably less than 8 cm.In this exemplary embodiment of a printing system 2, the distance from the component 4 has been determined to be 10 cm.The invention furthermore provides that the radiation source 18 is configured and designed in such a way that its electrical energy requirement is less than 2.9 kilowatts, preferably less than 2.5 kilowatts, preferably at 2.1 kilowatts, wherein in this exemplary embodiment of a printing system 2 the radiation source 18 has an energy requirement of 2.1 kilowatts for its operation.The coloring compound 11 used for the marking 6 of the component 4 is free of curing agent and free of silicone in this exemplary embodiment and also has a retardant.The printing system 2 shown in FIG. 1 is designed and designed to print components 4, the housings 5 of which consist of a plastic, in order to provide these with the desired marking 6. The plastic of the respective housing 5 of the components 4 shown in FIG. 1 is formed from a polyamide, wherein the respective identification surface 24 before the printing has a roughness with a mean roughness Ra of a low VDI class 21 according to Guideline VDI 3400 in the present version as well as a surface energy of less than 42 mN / m as well as a surface moisture of greater than or equal to 2 mass percent.According to the invention, the printing system 2 uses a pad printing method and therefore comprises the pad printing means 10 already mentioned. In this case, the ink mass 11 is transferred by means of an elastic stamp 34, the so-called tampon, from a printed image carrier 36, the so-called cliché, to the component 4 for its identification.For this printing process, the print image carrier 36 has a surface 38 which is provided with a print image for representing the marking 6. In the case of the printing system 2 shown in FIG. 1, the printed image is produced by a etching method in the case of the printed image carrier 36 which consists of a metal material, with the result that the surface 38 has depressions for a contour which represents the designation 6.The ink composition 11 is applied to the printed image carrier 36 by means of a doctor blade 40 in such a way that it remains in the depressions of the surface 38. The ink mass 11 is fed beforehand to the printed image carrier 36, which is here clear by means of a symbolized pivotable casting trowel 41. The marking 6 is applied to the component 4 by the stamp 34 receiving the ink mass 11 located in the depressions and transferring it to the component 4 by pressing the stamp 34 onto the marking surface 24 of the respective component 4.FIG. 2 shows the printing system 2 from FIG. 1 in an active state by the components 4 being irradiated with NIR radiation 20. For this purpose, the radiation source 18 is activated, so that the NIR radiation 20 is directed onto the respective identification surface 24 of the component 4 to be irradiated.FIG. 3 shows a second exemplary embodiment of a printing system 2 according to the invention, which is again referred to below as printing system 2 for short. The printing system 2 shown in FIG. 3 differs from the printing system 2 shown in FIGS. 1 and 2 in particular in that the irradiation device 16 has at least one limiting element 42 which is configured and designed to limit the radiation field 22. The limiting element 42 is arranged between the radiation source 18 and the component 4 during the irradiation of the component 4 in question.For this purpose, the delimiting element 42 has a delimiting body 44, which is configured and designed to delimit the radiation field 22 in a first spatial direction 46 and a second spatial direction 48 and for this purpose is designed in the manner of a radiation screen 52 in this exemplary embodiment. This is formed by a formed plate 54 which has an opening 56 as a passage for the NIR radiation 20.The second spatial direction is symbolized in FIG. 3 or FIG. 4 by a circle symbol with inserted center point and cross and directed out of or into the representation plane.The first and second spatial directions 46, 48 are arranged transversely to the radiation direction 50, in which the radiation source 18 emits the NIR radiation 20 or emits it onto the component 4 to be irradiated. Furthermore, the spatial directions 46, 48 are oriented transversely or orthogonally to one another.In contrast to the printing system 2 shown in FIG. 1 or FIG. 2, in the printing system 2 shown in FIG. 3, the delimiting body 44 is configured and designed such that the NIR radiation 20 is directed onto a single component 4 for drying the ink mass 11' applied thereto.A printing system 2 according to the invention can have further differences from the first and also second exemplary embodiments.Thus, for example, the third exemplary embodiment of a printing system 2 according to the invention, which is illustrated in FIG. 4, shows a delimiting element 42 which is configured and formed as a radiation screen 52 and is formed here from a curved plate 54 which in turn has an opening 56 as a passage for the NIR radiation 20. It is thus possible to dry the individual components 4 in a very targeted manner and to adapt the drying or irradiation process thereto.On the basis of the figures, in particular FIGS. 1 and 2, a pad printing method according to the invention for applying a marking 6 to a marking surface 24 of a component 4 with a printing system 2 according to the invention is also evident, in which, in a first step, the component 4 is supplied to the printing device 8 by means of the supply device 12, and wherein, in a second step, the marking 6 is produced by applying the ink composition 11 to the marking surface 24 of the component 4 by pad printing means 10 of the printing device 8, wherein, in a third step, which is downstream of the second step in a process series, the marking surface 24 of the component 4 with the ink composition 11' applied thereto is irradiated with an NIR radiation 20 by means of an irradiation device 16. The irradiation device 16 is configured and configured such that the identification surface 24 of the component 4 supplied to the printing device 8 by the supply device 12 is irradiated directly by means of the NIR radiation 20 generated by the radiation source 18. The further possible embodiments of a pad printing method according to the invention result analogously to the printing systems 2 according to the invention or pad printing method according to the invention illustrated with reference to the figures.A printing system 2 according to the invention as well as analogously a pad printing method according to the invention can be formed in various ways, so that the aforementioned exemplary embodiments are only a small selection of possible embodiments according to the invention of a printing system 2. The features explained with reference to the figures are not tied to the corresponding constellations, so that they can also form printing systems 2 according to the invention or a pad printing method according to the invention independently of these in other constellations.List of reference characters2 Printing system 4 Component 4' Set of components 5 Housing of the component 6 Marking 8 Printing device 10 Pad printing means 11 Ink mass 11' Ink mass (applied) 12 Feed device 14 Conveying means 14' Conveyor belts 16 Irradiation device 18 Radiation source 20 NIR radiation 22 Radiation field 24 Marking surface 26 Control element 28 Sensor 28' Proximity sensor 30 Control line 32 Active region of the radiation source 34 Stamp 36 Print image carrier 38 Surface of the print image carrier 40 Squeegee 41 Casting trowel 42 Delimiting element 44 Delimiting body 46 First spatial direction 48 Second spatial direction 50 Radiation direction 52 Radiation screen 54 Plate 56 OpeningReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Cited Non-Patent LiteratureDIN EN ISO 4287:2010

[0095]

Claims

Printing system (2) for a component (4) having a printing device (8) for applying an identification (6) to the component (4), wherein the printing device (8) has pad printing means (10) for applying a colour mass (11) to an identification surface (24) of the component (4) for the identification (6), having a feed device (12) which has conveying means (14) and feeds the component (4) to the printing device (8) by means of the conveying means (14), having an irradiation device (16) which is arranged downstream of the printing device (8) in a process, wherein the irradiation device (16) has a radiation source (18) for generating an NIR radiation (20) for drying the colour mass (11) applied to the component (4), characterized in that the irradiation device (16) is designed and configured in such a way that, the radiation source (18) generating at least one radiation field (22) for irradiating the component (4), wherein the NIR radiation (20) acts directly on the component (4), in particular on the identification surface (24), preferably on the coloring composition (11) applied on the identification surface (24).Printing system (2) according to Claim 1, characterized in that the irradiation device (16) is configured and designed in such a way that the radiation field (22) is directed directly onto the component (4), in particular onto the identification surface (24).Printing system (2) according to Claim 1 or 2, characterized in that the irradiation device (16) has a control element (26) which is designed and designed in such a way that it pulses the irradiation of the component (4), in particular of the colour mass (11) applied to the marking surface (24), with NIR radiation (20) by means of an adjustable or preset irradiation duration.Printing system (2) according to Claim 3, characterized in that the control element (26) cycles the irradiation duration with a time value of between 0.4 and 1.2 seconds, preferably between 0.5 and 0.7 seconds, most preferably 0.6 seconds.Printing system (2) according to Claim 3 or 4, characterized in that the control element (26), in an operatively connected control connection to the irradiation device (16), actuates the irradiation device (16) in such a way that the irradiation device (16) changes between an active state, in which it generates the NIR radiation (20) for the radiation field (22), and an inactive state, in which the radiation source (18) is deactivated.Printing system (2) according to one of Claims 3 to 5, characterized in that the control element (26) tunes the irradiation duration to the feeding of the component (4) by the feeding device (12) and synchronizes irradiation by the radiation source (18) with entry of the component (4) into an active region (32) determined by the radiation field (22).Printing system (2) according to one of the preceding claims, characterized in that the radiation source (18) for irradiating the component (4) is arranged in a vicinity to the component (4), in particular to the identification surface (24), in particular at a distance from the component (4), in particular to the identification surface (24), equal to or less than 15 cm, preferably equal to or less than 10 cm, most preferably equal to or less than 8 cm.Printing system (2) according to one of the preceding claims, characterized in that the radiation source (18) is configured and designed in such a way that its electrical energy requirement for providing the NIR radiation (20) is equal to or less than 2.9 kilowatts, preferably equal to or less than 2.5 kilowatts, preferably equal to or less than 2.1 kilowatts.Printing system (2) according to one of the preceding claims, characterized in that the irradiation device (16) has at least one limiting element (42) which is set up and designed to limit the radiation field (22).Printing system (2) according to Claim 9, characterized in that the delimiting element (42) has at least one delimiting body (44) which is designed and designed to delimit the radiation field (22) in a first spatial direction (46) and a second spatial direction (48), in particular is designed in the manner of a pinhole diaphragm and / or slit diaphragm and / or a radiation screen (52).Printing system (2) according to one of the preceding claims, characterized in that the ink composition (11) is free from curing agent and / or free from silicone.Printing system (2) according to one of the preceding claims, characterized in that the ink composition (11) has a retardant.Printing system (2) according to one of the preceding claims, comprising at least one component (4) to be marked, wherein at least the marking surface (24), in particular a housing (5) of the component (4) on which the marking surface (24) is arranged, is formed at least in sections from a plastic, in particular from a polyamide, or has a plastic, in particular a polyamide, and wherein in particular the marking surface (24) has at least in sections • a roughness with a mean roughness value Ra {according to Directive VDI 3400 in the current mount} of low VDI class 21 or • a surface energy of less than or equal to 42 mN / m or • a surface humidity of greater than or equal to 2 percent by mass.Pad printing method for applying a marking to a marking surface (24) of a component (4) with a printing system (2) which is formed in particular according to one of Claims 1 to 14, in which, in a first step, the component (4) is supplied to a marking device by means of a supply device (12), and wherein, in a second step, the marking (6) is produced by applying a colour mass (11) to a marking surface (24) of the component (4) by pad printing means (10) of the marking device, wherein, in a third step, which is arranged downstream of the second step in a process series, the marking surface (24) of the component (4) to which the colour mass (11) is applied is irradiated with an NIR radiation (20) by means of an irradiation device (16), characterized in that the irradiation device (16) is designed and configured in such a way, the identification surface (24) of the component (4) supplied to the identification device by the supply device (12) is irradiated directly by means of the NIR radiation (20) generated by the radiation source (18).Pad printing method according to claim 14, characterised in that in this case in particular the irradiation of the component (4), in particular of the colour mass (11) applied to the identification surface (24), with NIR radiation (20) is clocked by a preset irradiation duration, or in particular the irradiation duration is preset with a time value between 0.4 to 1.2 seconds, preferably between 0.5 to 0.7 seconds, most preferably 0.6 seconds, or in particular the irradiation duration is synchronised with an entry of the component (4) into an active region (32) determined by the radiation field (22), or in particular a radiation source (18) for irradiating the component (4) is provided, which is arranged in a close range to the component (4), in particular to the identification surface (24), in particular at a distance from the component (4), in particular to the identification surface (24), of less than 15 cm, The device according to the invention is preferably configured and configured such that its electrical energy requirement is less than 2.9 kilowatts, preferably less than 2.5 kilowatts, preferably at 2.1 kilowatts, or in particular the NIR radiation (20) is limited by at least one limiting element (42), or a component (4) is printed in which at least the identification surface (24), in particular a housing (5) of the component (4) on which the identification surface (24) is arranged is formed at least in sections from a plastic, in particular from a polyamide, or a plastic, in particular a polyamide, or a plastic, in particular a polyamide, having in particular the marking surface (24) at least in sections • a roughness with a mean roughness Ra of less than VDI 21 {according to Guideline VDI 3400 in the present version} or • a surface energy of less than or equal to 42 mN / m or • a surface moisture of greater than or equal to 2 mass percent.

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