Machine and method for applying at least one graphic to a wooden rod

Abstract

The machine (2) and the method for applying at least one graphic to a wooden rod (1) has a printing unit with at least one print head for print medium, such as ink. In order to design the machine (2) and the method in such a way that the production of printed wooden rods (1) is simple and cost-effective, at least one pre-treatment unit is connected upstream of the printing unit inside the machine (2) and / or at least one post-treatment unit is connected downstream. Inside the machine (2), the wooden rod (1) is pre-treated and / or post-treated before and / or after the printing process.

Description

[0001] Machine and method for applying at least one graphic to a wooden stick

[0002] The invention relates to a machine for applying at least one graphic to a wooden stick according to the preamble of claim 1 and to a method for applying at least one graphic to a wooden stick according to the preamble of claim 10.

[0003] To apply a graphic to wooden sticks, the graphic is printed onto a wrapping material, which is then wrapped around the wooden sticks. A protective layer, such as a clear varnish, is then applied to the wrapping material to protect the graphic from external influences.

[0004] Different machines are required for the printing process, the wrapping and the application of the protective layer, which not only makes the production of printed wooden sticks considerably more expensive but is also very complex.

[0005] The invention is based on the object of designing the generic machine and the generic method in such a way that the production of printed wooden bars is possible in a simple and cost-effective manner.

[0006] This object is achieved in the generic machine according to the invention with the characterizing features of claim 1 and in the generic method according to the invention with the characterizing features of claim 10.

[0007] With the machine according to the invention, not only is the printing of the wooden stick carried out within the machine, but the wooden stick is also subjected to pre-treatment and / or post-treatment as required. For this purpose, the machine is equipped with at least one pre-treatment unit and / or at least one post-treatment unit in addition to the printing unit. Thus, with the machine according to the invention, the wooden stick can be printed very easily in such a way that it no longer requires any further post-treatment after leaving the machine, but can be used immediately for its intended purpose.

[0008] The pretreatment unit advantageously has at least one print head for applying a coating to the wooden stick. This makes it possible to prepare the upper surface of the wooden stick to be printed before the printing process so that the graphic can be applied perfectly to the wooden stick.

[0009] The pretreatment unit is advantageously equipped with at least one drying device. This makes it possible to dry the surface to be printed sufficiently before the printing process to ensure a flawless print job.

[0010] The post-treatment unit is preferably equipped with at least one device for applying a cover layer to the printed graphic. The cover layer forms a protective layer to protect the graphic on the wooden stick.

[0011] It is advantageous if the post-treatment unit has at least one drying device. This makes it possible to dry the wooden stick sufficiently before leaving the machine so that it can be easily handled immediately upon leaving the machine.

[0012] The printing unit is advantageously designed to apply multi-color printing to the wooden bar. For this purpose, appropriate print heads are provided for different colored inks. To achieve optimal print quality, the print heads are advantageously adjustable relative to the wooden bar. This makes it possible to optimally adjust the distance of the print heads from the surface to be printed, ensuring a precise, sharp, and clean print image.

[0013] The adjustability of the print heads also allows them to be adapted to different angles on the wooden stick, for example, to print on the top surfaces of the stick. For example, the wooden stick may have slanted surfaces that can be printed on perfectly thanks to the adjustability of the print heads. The adjustability of the print heads also makes it possible to print on all long sides of a wooden stick, for example.

[0014] Finally, the advantageous adjustability of the print heads allows two differently angled top surfaces of the wooden stick to be printed simultaneously. This keeps the number of print heads within a reasonable range.

[0015] The print heads are preferably adjustable in a controlled manner. This allows the print heads to be aligned with the top surface of the wooden stick being treated / printed during the printing and / or treatment process. For example, it is possible to print perfectly on top surfaces that are curved or slanted in the direction of transport of the wooden stick, because the control allows the print heads to be precisely adjusted.

[0016] For this measure, it is advantageous if the position and orientation of the upper side of the wooden stick to be printed are previously detected using sensors, camera systems, and the like, and the corresponding signals are fed to a controller, which, based on these signals, controls the print heads so that they reach their respective printing / treatment positions. In an advantageous embodiment, the machine is equipped with at least one transport device for transporting the wooden stick through the machine. The transport device allows the wooden stick to be reliably guided through the machine in order to perform the required processes on the wooden stick.

[0017] The transport device extending through the machine is advantageously adjustable so that a desired transport speed of the wooden bar can be reliably set as it passes through the machine, so that the graphic can be applied with high precision.

[0018] In the process according to the invention, the wooden stick is treated or post-treated within the machine before and / or after the printing process. This allows the wooden stick to be printed on easily, so that after leaving the machine, it requires no further post-processing. The wooden stick can be used directly for its intended purpose.

[0019] In an advantageous process, the wooden stick is coated with a filler and / or a primer and / or a base coat before printing. This allows the surface to be printed to be pretreated so that the graphic can then be applied to the wooden stick with high precision.

[0020] Another advantageous approach is to dry or partially dry the wooden stick on its upper side before printing. This allows for easy application of the printing medium, resulting in a clean print image.

[0021] The wooden stick is preferably dried or partially dried after printing and / or provided with a protective layer on the printed side. This protective layer protects the printed surface of the wooden stick during further handling. Drying or partially drying the wooden stick on the printed side ensures that the print job is not compromised during further handling after the printing process.

[0022] The optimal process is to print the wooden stick in a continuous process. This eliminates the need to position the wooden stick between individual processing steps. This not only improves the accuracy of the pre- and post-treatment and the printing process, but also shortens processing times.

[0023] It's advantageous if the wooden stick is transported at a constant speed. This allows the feed rate of the wooden stick to be optimally adjusted.

[0024] It is advantageous if the outline of the wooden stick is captured by sensors and / or camera systems. This allows the position and orientation of the top surface of the wooden stick to be printed to be precisely determined.

[0025] The signals from the sensors and / or camera systems are advantageously fed to a controller which, depending on the signals, adjusts the print heads relative to the printing surfaces of the wooden bar.

[0026] The subject matter of the application arises not only from the subject matter of the individual patent claims, but also from all information and features disclosed in the drawings and the description. Even if they are not the subject matter of the claims, they are claimed as essential to the invention insofar as they are novel, individually or in combination, over the prior art.

[0027] Further features of the invention emerge from the further claims, the description and the drawings. The invention is explained in more detail with reference to an embodiment shown in the drawings.

[0028] Fig. 1.1 shows a schematic representation of three process steps when applying a graphic to a wooden stick,

[0029] Fig. 1.2 in a schematic representation similar to Fig. 1.1 other process steps when applying a graphic to a wooden stick,

[0030] Fig. 1.3 in a representation corresponding to Fig. 1.1 another sequence of process steps when applying a graphic to a wooden stick,

[0031] Fig. 2 shows a schematic representation and a front view of two print heads used to print on a wooden stick,

[0032] Fig. 3 shows a schematic representation of a machine according to the invention for applying a graphic to a continuous wooden stick.

[0033] Using the procedure described below, it is possible to directly print on the top of a wooden stick. This can be done by applying a graphic, which could be a sketch, a photo, or the like. The printed wooden sticks can then be assembled into a final product, such as a board, a frame, and the like. In this case, the wooden sticks are printed in such a way that the desired graphic is created on the final product. The wooden sticks are advantageously printed using a digital printing machine, which is known per se and will therefore not be explained in more detail. The printing machine is designed to print the wooden sticks in the required manner as they are transported past one or more print heads of the printing machine. Digital printing refers to inkjet printing processes.

[0034] Preferably, the wooden bars are transported through the printing press during the printing process. However, it is also possible for the wooden bars to remain stationary while the printing press's print heads move relative to the wooden bars, i.e., move past them. The relative movement between the wooden bars and the print heads can also be achieved by moving them relative to each other during the process, so that the wooden bars are printed to the desired extent.

[0035] The wooden bars can be made of solid wood or wood-based materials, such as MDF.

[0036] The wooden sticks are printed one after the other so that the final product, after the wooden sticks are assembled or arranged, has the desired graphic.

[0037] On the other hand, printing on the wooden sticks is not dependent on them being used to create a graphic on a final product. In principle, the process is also suitable if, for example, each wooden stick has its own graphic that is not part of an overall graphic on the final product.

[0038] Fig. 1.1 schematically shows a wooden bar 1, which has an elongated extension and is transported in its longitudinal direction through a machine 2, in which different process steps are carried out for printing the wooden bar 1. Therefore, different machines are not necessary for the various process steps, which would also have to be linked together with appropriate transport devices.

[0039] In a first process step I, the wooden stick 1 is pretreated in the machine 2. In a subsequent process step II, the digital printing is carried out on the wooden stick 1. In the final process step III, the wooden stick 1 is subjected to a post-treatment.

[0040] In process step I, a filler 3 can be applied to the wooden stick 1. This filler can be used to provide a highly absorbent surface of the wooden stick 1 with a liquid base coating that is printable and imparts the wooden stick 1 with a desired surface structure and property. This property can, for example, consist of forming a closed, non-absorbent or only slightly absorbent surface on a highly absorbent surface, such as that typically found on a wooden stick, so that the subsequent printing is successful.

[0041] In process step I, a primer 4 can then be applied, which can be used as an adhesion promoter between the different materials of the wooden rod 1 and the subsequent coating.

[0042] Two separate print heads can be provided for the application of filler 3 and primer 4. However, it is also possible to use a combined print head for the application of filler 3 and primer 4. The use of a combined print head is possible because filler 3 and primer 4 are chemically combined as a single substance. With the print heads, an appropriate amount of the corresponding liquid can be applied to the printable side of wooden stick 1 using the digital printing process. Depending on the nature of the top side of wooden stick 1 to be printed, filler 3 and primer 4 can be applied one after the other. Depending on the surface condition, it is also sufficient to apply only filler 3 or only primer 4.

[0043] Ideally, it is not necessary to subject the printed surface of the wooden stick 1 to an abrasive process step, such as sanding. If necessary, the printed side of the wooden stick 1, which has been pretreated with filler 3 and / or primer 4, can be provided with a base coat 21. A white base coat can be applied, for example, using an inkjet process. This process step is optional and not mandatory.

[0044] A combined print head can be used for the application of Filler 3 and Base Coat 21 or for the application of Primer 4 and Base Coat 21 if - as with Filler 3 and Primer 4 - Filler 3 and Base Coat 21 or Primer 4 and Base Coat 21 are chemically combined as one substance.

[0045] In process step I, a pinning process 5 can be performed following the application of the filler 3 and / or the primer 4 and / or the base coating 21. This pinning process 5 serves to dry the upper side of the wooden bar, which has been coated with the filler 3 and / or the primer 4 and / or the base coating 21, to such an extent that the printing process can take place immediately thereafter in process step II.

[0046] In the exemplary embodiment, one print head is provided for each of the filler 3, the primer 4, and the base coating 21. In principle, more than one print head can be provided for the filler 3 and / or the primer 4 and / or the base coating 21, for example, to apply multiple layers or achieve better coverage.

[0047] For the pinning process, a corresponding unit is provided, which is installed analogously to the print heads in the printing machine 2 and has at least one drying unit, such as a UV or LED unit. Such units are known and therefore will not be explained in detail.

[0048] Pinning process 5 can be advantageously carried out using UV lamps. Other suitable energy sources for the drying process are also conceivable. Pinning process 5 is tailored to the overall printing process and the printing medium used, such as ink.

[0049] The pinning process 5 can be carried out after the application of the filler 3 or the primer 4 or the base coat 21, as required.

[0050] As the wooden stick 1 is further transported through the printing press 2, it enters the digital printing area II, where the desired decoration is applied to the wooden stick 1, preferably using a four-color print. The decoration can be, for example, a graphic, an image, or a pattern.

[0051] As an example, Fig. 1.1 shows that the decoration is printed with four print heads / colors 6 to 9, of which, for example, color 6 is black, color 7 is yellow, color 8 is magenta, and color 9 is cyan. With these four colors 6 to 9, a very high image quality can be produced in four-color printing.

[0052] Depending on requirements, special colors, such as neon colors, can also be used for printing. The printing press 2 can also have at least one additional color, which can expand the color space. In this case, the decoration is applied to the wooden bar 1 using a multi-color print rather than a four-color print.

[0053] Additional print heads are used for the special color and / or the additional color.

[0054] More than one print head may be provided for each color to allow multiple printing and / or better coverage.

[0055] Following the four- or multi-color printing, a pinning process 5 can be used to dry the ink applied to the wooden stick 1. This makes it possible to subject the wooden stick 1 to post-treatment according to process step III immediately after the printing process in process step II.

[0056] In process step III, a protective layer is first applied to the printed side of the wooden stick 1 using a coating process 10. In this coating process, the coating is advantageously applied using an inkjet process. The coating process 10 can be used to modify the surface properties of the printed wooden stick 1. For example, the top layer can be used to mattify the printed surface or achieve a specific degree of gloss. Another coating option is to design it so that the printed side of the wooden stick 1 feels more valuable, for example, which can be achieved by a corresponding haptic design of the coating.

[0057] In particular, the coating serves to protect the printed upper side of the wooden stick 1 against external influences. In this case, the coating serves as mechanical protection for the printed side.

[0058] Furthermore, the coating can also be designed in such a way that it achieves a lotus effect, i.e. a water-repellent effect.

[0059] The coating can also be used to protect the printed side against chemicals such as cleaning agents or against UV radiation.

[0060] At this stage of the process, further protection mechanisms can be set using the corresponding print head and color management.

[0061] In process step III, a drying process 11 can be added to the coating process if the printing medium applied to the wooden bar 1 is not completely dry upon exiting the machine 2. A corresponding unit is used for the drying process, which, like the print heads, is inserted into the printing machine 2.

[0062] Fig. 1.2 shows that not all process steps are necessary to print the wooden bar 1 as it passes through the printing press 2. In the process according to Fig. 1.2, process step III for the post-treatment of the printed wooden bar 1 is not provided. In this case, it is sufficient to pretreat the wooden bar 1 in the manner described in process step I and to print it in the manner described in process step II.

[0063] Fig. 1.3 shows that process step I can be omitted if the process is implemented differently. In this case, the wooden bar 1, which passes through the printing machine 2 in its longitudinal direction, is printed in process step II and post-treated in process step III. Process steps III have been described with reference to Fig. 1.1, so reference can be made there.

[0064] Fig. 2 schematically shows, in a front view or in a section transverse to the transport direction 20 of the wooden bar 1 through the printing press 2, the possibility of providing the print heads of the printing press 2 so that they can also be used to treat or print inclined upper sides 13, 14 of the wooden bar 1. One print head 12 is shown in Fig. 2 as representative of the described print heads 3 to 11, 21.

[0065] The upper sides 13, 14 of the wooden rod 1 can also be inclined differently in the example shown.

[0066] Each upper side 13, 14 is assigned the corresponding print heads, which have been described with reference to Figs. 1.1 to 1.3. The double arrows in Fig. 2 indicate the various adjustment directions of the print heads 12. They can then be adjusted both vertically and horizontally, transversely to the transport direction 20 of the wooden bar 1 through the printing press 2. In addition, the print heads can be pivoted about an axis 15 parallel to the transport direction 20 of the wooden bar 1. Thanks to the various options, the respective print head 12 can be optimally adjusted to the position of the upper side of the wooden bar 1 to be printed or treated.

[0067] The print heads 12 can be adjusted to a vertical position so that it is possible, for example, if necessary, to also treat or print the vertical longitudinal sides 16, 17 of the wooden bar 1, which in the exemplary embodiment run parallel to one another in the transport direction 20 of the wooden bar 1.

[0068] Thanks to the vertical adjustment capability, the distance between the print heads 12 and the wooden bars 1 to be printed can be adjusted. The position of the print heads 12 relative to the wooden bar 1 can be adjusted automatically. For example, it is possible to install two sensors as the wooden bar 1 enters the printing machine, which detect the outline of the wooden bar 1. The sensors send corresponding signals to a control system, which can be used to adjust the print heads to the position required for printing on the wooden bar. Instead of individual sensors, the cross-sectional shape of the wooden bar 1 can also be detected by camera systems.

[0069] The print heads 12 can also be manually adjusted to the required printing position.

[0070] To adjust the print heads 12, an electric motor is advantageously provided, which can position the individual print heads precisely into the position required for printing or treating the wooden stick 1.

[0071] A protective device (not shown) in the inlet area 19 (Fig. 1.1 ) of the printing machine 2 prevents the wooden bar 1 from being transported into the printing machine 2 when the print heads are not yet in their correct position.

[0072] Fig. 3 shows the digital printing machine 2 in a schematic and perspective view. The wooden bar 1 passes through the machine 2 in its longitudinal direction in the transport direction 20. The described print heads for the various process steps 3 to 11, 21 are arranged in two rows. The lower or front row of print heads 3 to 11, 21 in Fig. 3 is assigned to the sloping top side 14, and the upper or rear row of print heads 3 to 11, 11, 21 is assigned to the horizontal top side 18 of the wooden bar 1.

[0073] Advantageously, the two rows of print heads are adjustable, as described with reference to Fig. 2. For this purpose, the print heads of each row can be arranged on a common support. The two supports can be adjusted independently of each other. It is also possible to provide at least one, preferably all, print heads in at least one of the two rows with adjustable capabilities.

[0074] Deviating from Fig. 3, the two rows of print heads can be arranged in the printing machine 2 according to the embodiment according to Fig. 2 in such a way that, for example, two oblique longitudinal sides 13, 14 located on different sides of the wooden bar 1 can be treated, as has been explained with reference to Fig. 2.

[0075] In principle, only one row of print heads can be provided for each of the various process steps 3 to 11, 21. This is particularly the case when the wooden bars 1 passing through the machine 2 are to be treated and printed on one side only. In this case too, it is advantageous if these print heads are adjustable relative to the wooden bar 1 so that different positions on the wooden bar 1 transported one after the other through the machine 2 can be treated and printed. It is also possible to use not just one, but two or more print heads for a single process step 3 to 11, 21. This is advantageous, for example, to achieve high coverage or to apply multiple layers.

[0076] To ensure that the decoration can be precisely applied to the wooden bar 1, it is ensured that the wooden bar 1 is always positioned relative to the print heads in such a way that the print image is not negatively affected. In particular, the wooden bar 1 is precisely positioned or guided transversely to the transport direction 20.

[0077] As it passes through the machine 2, the wooden stick 1 is guided on a guide (not shown). This guide can consist of one or more rails that run through the machine 2 in the transport direction 20 and on which one or more slides can be moved, on which the wooden stick 1 is fixed. To ensure precise positioning of the wooden stick 1 on the slide, the wooden stick is first aligned transversely to its longitudinal direction, for example with the aid of a lateral stop or lateral guide extending in the transport direction 20. Once the wooden stick 1 is aligned on the slide in this way, it is clamped in a known manner so that it reliably maintains its position on the slide as it passes through the machine 2.

[0078] After the last process step 1 1 in the machine 2, the fixation of the wooden bar 1 on the carriage is released and the wooden bar 1 is ejected from the printing machine 2 either manually or automatically.

[0079] The carriage(s) can be motor-driven. Other drive means, such as a conveyor belt, a pushing device, and the like, can also be used to transport the wooden stick 1 through the machine 2. Exact positioning of the wooden stick 1 as it passes through the machine 2 can be dispensed with if the print heads can be adjusted to their respective printing positions in a controlled manner. If the position of the top sides to be printed on the wooden stick 1 is detected by sensors or camera systems before entering the machine 2, the position and orientation of the top side of the wooden stick 1 to be printed is known, at least upon entering the machine 2. The signals sent by the sensors or camera systems to the control system are then used to position the print heads according to the orientation of the top side.

[0080] With such a particularly advantageous design, it is even possible to adjust the print heads transversely to the transport direction 20 while the wooden bar 1 is passing through the machine 2 so that the desired print image can be generated on the respective upper side. This makes it possible to precisely apply a decoration to upper sides that are curved in the transport direction 20. The respective print head is adjusted according to the curvature running in the transport direction 20.

[0081] Similarly, by controlling the print heads, it is possible to precisely process and print height differences in the upper side of the wooden bar 1 to be printed. The sensors or camera systems are designed to detect height differences in the upper side of the wooden bar 1 to be printed, allowing the respective print heads to be adjusted accordingly in the height direction.

[0082] Since the print heads can be adjusted both vertically and horizontally, as well as around the pivot axis 5 (Fig. 2), the print heads can always be precisely aligned with the upper side of the wooden bar 1 to be printed. With machine 2, relatively high feed speeds can be achieved, for example, approximately 40 m / min. A throughput of at least 15 linear meters per minute can be achieved over the entire production time.

[0083] With machine 2 it is possible to print the wooden stick 1 on only one side or on several sides.

[0084] As can be seen from Fig. 2, with the two rows of print heads 12 shown there, not only the inclined upper sides 13, 14 can be printed, but also the horizontal upper side 18. With appropriate positioning of the print heads 12, in addition to the inclined upper sides 13, 14, the vertical longitudinal sides 16, 17 of the wooden bar 1 can also be printed.

[0085] In principle, it is also possible to use, for example, three rows of print heads for each process step 3 to 11, 21. Then, three sides of the wooden bar 1 can be printed, which are at an angle to each other.

[0086] In the illustrated and described embodiment, two or more sides of the wooden bar 1 are printed simultaneously. For this purpose, the corresponding print heads are located at the same height in relation to the transport direction 20, i.e., essentially next to each other. However, it is also possible to arrange the print heads for the individual workpiece sides one behind the other in the transport direction 20, so that the different sides of the wooden bar 1 are printed sequentially.

[0087] In an advantageous further development, the print heads 3 to 11, 21 can be adjustable transversely to the transport direction 20 during the passage of the wooden bar 1. This allows for printing or processing on sides of the wooden bar 1 that are wider than the working area of ​​the print heads 3 to 11, 21. Generally, however, the individual print heads are designed to print across the entire width of the respective surface.

[0088] Depending on the profile design of the wooden stick 1, it is also possible to print on two different sides of the wooden stick 1 simultaneously with one print head. This is possible, for example, if the two sides are only slightly inclined towards each other.

Claims

Claims 1 . Machine for applying at least one graphic to a wooden stick (1 ) with a printing unit with at least one print head (12) for printing medium, such as ink, characterized in that the printing unit within the machine (2) at least one pretreatment unit is connected upstream and / or at least one post-treatment unit is connected downstream.

2. Machine according to claim 1, characterized in that the pretreatment unit has at least one print head (21) for applying a coating to the wooden bar (1).

3. Machine according to claim 1 or 2, characterized in that the pretreatment unit has at least one drying device (5).

4. Machine according to one of claims 1 to 3, characterized in that the post-treatment unit has at least one device (10) for applying a cover layer to the printed graphic.

5. Machine according to one of claims 1 to 4, characterized in that the post-treatment unit has at least one drying device (11).

6. Machine according to one of claims 1 to 5, characterized in that the printing unit for multi-color printing has several print heads (12) for different colored printing inks.

7. Machine according to one of claims 1 to 6, characterized in that the printing heads (12) are arranged relative to the wooden bar (1 ) are adjustable.

8. Machine according to claim 7, characterized in that the print heads (12) are adjustable in a controlled manner.

9. Machine according to one of claims 1 to 8, characterized in that the machine (2) has at least one transport device with which the wooden stick (1) is transported through the machine (2) is transportable.

10. Method for applying at least one graphic to a wooden stick (1), in particular with a machine according to one of claims 1 to 9, characterized in that the wooden stick (1) is pretreated or post-treated within the machine before and / or after the printing process.

11. Method according to claim 10, characterized in that the wooden stick (1) is provided with a filler (3) and / or a primer (4) and / or a base coating (21) before printing.

12. Method according to claim 1 or 11, characterized in that the wooden stick (1) is attached to its upper side (13, 14; 16 to 18) to be printed is dried.

13. Method according to one of claims 10 to 12, characterized in that the wooden stick (1) is dried after printing and / or provided with a protective layer on the printed side.

14. Method according to one of claims 10 to 13, characterized in that the wooden stick (1) is printed in a continuous process.

15. Method according to one of claims 10 to 14, characterized in that the wooden stick (1) is transported at a constant speed.

16. Method according to one of claims 10 to 15, characterized in that the outline shape of the wooden stick (1) is detected by sensors and / or camera systems.

17. Method according to claim 16, characterized in that the signals of the sensors and / or camera systems are fed to a control which, depending on the signals, adjusts the print heads (12) relative to the upper sides (13, 14); 16 to 18) to be printed.

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