Printing device for printing a web-shaped substrate

Abstract

The invention relates to a printing device (200) for printing on a web-shaped substrate (300), in particular for printing portrait images on the substrate for identification, security, or other documents, comprising a supply unit (202) for supplying the web-shaped substrate (300) from a roll (302), a substrate guide (204) consisting of one or more deflection rollers (206) to guide the web-shaped substrate (300) to a printing area (206), wherein a slidably mounted printing table (210) with a vacuum unit is provided in the printing area (206) to fix the web-shaped substrate (300) section by section with a vacuum, and wherein a printhead (212) is provided in the printing area (208) that is held stationary during the printing process and is configured to apply a printed image to the substrate (300) by means of a displacement of the printing table (210) together with the substrate fixed thereto. (300).

Description

[0001] The invention relates to a printing device for printing on a web-shaped substrate, in particular for printing the substrate with portrait images for identification, value or security documents.

[0002] Identification, security, or other identification documents typically include personalized imprints, such as a portrait of the owner. Production facilities such as the one described in DE 10 2018 119 178 A1 are suitable for manufacturing such identification, security, or other identification documents. This production facility for manufacturing data cards for security documents from a laminate composite comprises two decoupled processing lines: a production line and a personalization line. In The personalization line is used, for example, to attach the portrait image, which was previously printed onto a substrate, especially a foil.

[0003] JP 2008 012 812 A describes a printing device in which the printhead is stationary and a sliding print table is used to apply the printed image. The print table is a suction plate used to flatten the substrate to be printed (roll-to-roll).

[0004] EP 3 693 178 A1 describes a printing device in which the substrate is guided by means of a vacuum suction plate of a movable printing table.

[0005] JP 2014 028440 A refers to a printing device that uses a continuous printing process (one web). It describes, in connection with its Figure 1 and 4 a splice unit, which may be provided together with a buffer unit in the printing device.

[0006] JP 2016 159999 A discloses a web position change device. This device is used to change the reference position in the width direction of a long, strip-shaped substrate. Furthermore, a processing system incorporating the web position change device for changing the reference position in the width direction of the long, strip-shaped substrate is described, as well as a method for changing the web position.

[0007] US 2015 / 158313 A1 describes a printing device that includes a pretreatment station to pretreat the paper provided on a roll before it is subsequently printed with a UV ink.

[0008] The object of the present invention is to provide a printing device which has more compact dimensions compared to printing devices known from the prior art.

[0009] This problem is solved by a printing device with the features of claim 1. Advantageous embodiments with expedient further developments of the invention are specified in the dependent claims.

[0010] The printing device according to the invention for printing on a web-shaped substrate, in particular for printing portrait images on the substrate for identification, security, or other documents, comprises a supply unit for feeding the web-shaped substrate from a roll. The printing device further comprises a substrate guide consisting of one or more deflection rollers to guide the web-shaped substrate to a printing area. Within the printing area, a slidably mounted or slidably adjustable printing table with a vacuum unit is provided to fix the web-shaped substrate to the printing table section by section using a vacuum. Also located within the printing area is a printhead, which is held stationary during the printing process and is configured to apply a printed image to the substrate by moving the printing table together with the substrate fixed to it.

[0011] This design of the stationary printhead and the movable print table results in a reduction of the print area length.

[0012] It has proven advantageous to have a splicing unit located downstream of the feed unit in one web transport direction, but upstream of the printing area. This splicing unit joins the layer of the transport web to be printed with a new roll, allowing printing or production to continue without downtime. Further space savings are achieved by appropriately positioning the splicing unit within the printing unit, particularly by placing it directly downstream of the feed unit.

[0013] In other words, a splice unit is a unit that is set up to attach a roll end of a substrate web of a (nearly empty) first roll to a roll beginning of a substrate web of a new (full) roll.

[0014] In this context, it is also advantageous to have a buffer unit for the temporary storage of the unwound web-like substrate, located downstream of the supply unit in one web transport direction but upstream of the printing area. This allows the buffer to compensate for the movements of the transport web or the web-like substrate caused by the movement of the printing table, ensuring a sufficient supply of substrate for printing.

[0015] It is advantageous if the buffer unit has at least one movable guide roller, and if the buffer unit is designed, thanks to its movable guide roller, to compensate for changes in the length of the web-shaped substrate that occur during the printing process due to the movement of the printing table. Thus, the movable guide roller acts like a kind of "dancer" to compensate for these changes in length. This ensures that the transport web remains taut and no defective print images occur when printing on the substrate.

[0016] To achieve the best possible print quality even after further processing of the substrate, it has proven advantageous to dry the ink applied to the substrate after printing. For this purpose, it is advantageous that, according to the invention, a drying oven is provided which is located downstream of the printing area in a web transport direction.

[0017] It has also proven advantageous to detect rejects early. For this reason, the invention provides for at least one inspection unit for the web-shaped substrate, which is located downstream of the printing area in the web transport direction but upstream of the drying oven. This allows the printing unit to be designed particularly compactly, and rejects are detected close to the printing area. Furthermore, in the event of a printing error, this significantly reduces the handling effort required in the subsequent process to reposition the necessary substrate strip for printing to the correct location in the production plant.

[0018] It is advantageous if the printhead can be moved vertically relative to the adjustment movement of the print bed, between a maintenance position, in which it faces a cap and can be closed or is closed by it, and a printing position, in which it faces the print bed and the web-shaped substrate fixed to it for printing. Thus, the movement of the printhead is not used for the printing process itself, but only to move it into a maintenance position, where the print nozzles are covered by the cap or undergo active cleaning.

[0019] In order to achieve the most accurate print image possible, it has proven advantageous to have an alignment unit immediately in front of the printing area, which is set up to align the edges of the substrate with respect to the printing table.

[0020] The printing device can be designed to be particularly compact if the delivery unit is located on a top floor that lies above the printing area in the direction of fall, if, furthermore, the substrate guide first guides the web-shaped substrate over the printing area on the top floor before guiding the web-shaped substrate downwards in the direction of fall to a middle floor in which the printing area is located, and if the printed substrate is dispensed on a lower floor below the printing area in the direction of fall.

[0021] The machine can be made even more compact if the printed substrate is dispensed on the side where the supply unit is located, so that the printing device can be directly connected to a production plant; even without having to wind the printed substrate onto a roll again first.

[0022] Further features, properties, and advantages of the present invention are described in more detail below with reference to embodiments and the accompanying figure. All features described so far and below are advantageous both individually and in any combination. The embodiments described below are merely examples and do not limit the scope of the invention. The figure shows: Figure 1 is a perspective and schematic view of a printing device that is set up to be directly connected to a production plant for the manufacture of an identification, value or security document.

[0023] In the Figure 1 A printing device 200 for printing on a web-shaped substrate 300, in particular for printing the substrate with portrait images for identification, value or security documents, is shown.

[0024] The printing device 200 comprises a supply unit 202 for supplying the web-shaped substrate 300 from a roll 302. The unwound roll 302, in particular the web-shaped substrate 300, is guided through the printing device 200 by a substrate guide 204 with several deflection rollers 206.

[0025] A splice unit 214 is immediately connected to the supply unit 202 in order to join at least one layer of the substrate 300 supplied on the roll 302 with the substrate 300 of the preceding roll. The cutting unit 214, the supply unit 202 and a buffer unit 216, which will be explained later, are arranged in a top level 228 of the printing unit 200.

[0026] The splice unit 214 is located downstream of the supply unit 202 along a web transport direction 304, but upstream of a printing area 208, which will be explained in more detail later. The optional buffer unit 216 serves for the temporary intermediate storage of the unwound web-shaped substrate 300. The buffer unit 216, which is also located downstream of the supply unit 202 in the web transport direction 304, but upstream of the printing area 208, is also downstream of the splice unit 214. The buffer unit 216 includes, by way of example, a movable deflection roller 218. Due to this movable deflection roller 218, the buffer unit 216 is designed to compensate for changes in the length of the web-shaped substrate 300 that occur during the printing process due to the movement of a printing table 210. The movable deflection roller 218 is mounted so that it can be adjusted perpendicular to the direction of travel.

[0027] Starting from the buffer unit 216, an optional alignment unit 226 is located downstream. This alignment unit 226 is positioned directly upstream of the printing area 208 and is thus configured to align the edges of the substrate 200 with respect to the printing table 210. The substrate guide 204 guides the web-shaped substrate to the printing table 210 and thus to the printing area 208.

[0028] In the printing area 208, the movable and adjustable printing table 210 is located, which has a vacuum unit to fix the web-shaped substrate 300 section by section using a vacuum. For this purpose, the printing table 210 has, for example, a plate provided with several suction holes to draw the web-shaped substrate 300 onto the plate. The adjustment of the printing table 210 is also perpendicular to the direction of fall.

[0029] In the printing area 208, a printhead 212 is also present, which is held stationary during the printing process and is configured to apply a printed image to the substrate 300 by means of a displacement of the printing table 210 together with the substrate 300 fixed to it. In other words, the printhead 212 or printheads 212 with their print nozzles are stationary, with the printed image being created by the displacement of the printing table 210 relative to the printhead 212. To keep the web-shaped substrate 300 taut, one or more deflection rollers or one or more movable deflection rollers can optionally be provided to maintain tension in the web-shaped material during the printing process. In particular, the movable deflection rollers are designed like a "dancer" that is adjusted perpendicular to the direction of fall.

[0030] Once the substrate 300 in the printing area 208 has been printed with the image, the printed substrate is transported further in the transport direction 304, in this case downwards. Thus, the printing area 208 is located on a middle level 230, which is situated below the top level 228 of the printing device 200 in the downward direction.

[0031] On the lower level 232, a number of optional inspection units 222, 224 are located for inspecting the web-shaped substrate 300, particularly optically. In other words, the inspection units 222, 224 are located downstream of the printing area 208 in the web transport direction 304, but upstream of a drying oven 220. This allows rejects to be detected before drying, thus requiring the replacement of a smaller section of the web-shaped substrate 300 should any defects be found.

[0032] The web-shaped substrate 300 first passes through the inspection unit 222, which optically examines the underside of the substrate. Only then does the substrate 300 enter the inspection unit 224, which checks the printed image and the printed side. Downstream in the web transport direction 304 is the drying oven 220, which completely dries the still-wet ink. Finally, the substrate guide 204 delivers the printed substrate 300 laterally out of the printing unit 200.

[0033] The printed substrate 300 is carried out on the side of the printing device 200 where the supply unit 202 with its roll 302 of the substrate 300 is also located.

[0034] It can be seen that the provisioning unit 202 is located in the top floor 228, which is above the printing area 208 in the direction of fall, wherein the substrate guide 206 first guides the web-shaped substrate 300 over the printing area 218 in the top floor before guiding the web-shaped substrate 300 downwards in the direction of fall to the middle floor 230, in which the printing area is located, wherein the printed substrate 300 is output in a lower floor 232 below the printing area 208 in the direction of fall.

[0035] This design results in a particularly compact printing unit 200. In particular, its longest side is shorter compared to known printing units 200 of this type. To further limit the length of the printing unit 200 and thus save installation space, it is optionally provided that the printhead 212 is movable vertically with respect to the adjustment movement of the printing table 210 between a maintenance position, in which it is opposite a cap (or a "capping station") or can be closed or is closed by it, and a printing position, in which it is opposite the printing table 210 and the web-shaped substrate 300 fixed to it for printing.

[0036] The printing device 200 according to the invention has also proven successful because the printed web-shaped substrate 300 is no longer wound onto a roll, so that the printed web-shaped substrate 300 can be directly connected to the downstream production system. The chosen design results in a particularly compact printing device 200. LIST OF REFERENCE SYMBOLS

[0037] 200 Printing unit 202 Feed unit 204 Substrate guide 206 Deflection roller 208 Printing area 210 Printing table 212 Printhead 214 Cutting unit (splicing table) 216 Buffer unit 218 Adjustable deflection roller (dancer) 220 Drying oven 222 Inspection unit (bottom) 224 Inspection unit (top) 226 Alignment unit 228 Top level 230 Middle level 232 Bottom level 300 Substrate 302 Roller

Claims

1. A printing device (200) for printing on a web-shaped substrate (300), in particular for printing the substrate with portrait images for identity, value or security documents, with a supply unit (202) for supplying the web-shaped substrate (300) from a roll (302), with a substrate guidance (204) consisting of one or more pulleys (206) to guide the web-shaped substrate (300) to a printing area (206), wherein a displaceably mounted printing table (210) with a negative pressure unit is present in the printing area (206) in order to fix the web-shaped substrate (300) in sections with a negative pressure, and wherein a print head (212), which is held stationary during the printing process and is configured to apply a printed image to the substrate (300) by means of a displacement of the printing table (210) together with the substrate (300) fixed thereto, is present in the printing area (208), characterized in that a drying oven (220) is present which is downstream of the printing area (208) in a web transport direction (304), and in that at least one test unit (222, 224) for testing the web-shaped substrate (300) is present, which is downstream of the printing area (208) in the web transport direction (304) but upstream of the drying oven (220).

2. The printing device (200) according to claim 1, characterized in that a splice unit (214) is present which is downstream of the supply unit (102) in a web transport direction (304), but upstream of the printing area (208).

3. The printing device (200) according to claim 1 or 2, characterized in that there is a buffer unit (216) for temporary intermediate storage of the unwound web-shaped substrate (300), which is downstream of the supply unit (202) in a web transport direction (304), but upstream of the printing area (208).

4. The printing device (200) according to claim 3, characterized in that the buffer unit (216) has at least one displaceable pulley (218), and in that the buffer unit (216), by virtue of its displaceable pulley (218), is configured to compensate for a change in length of the web-shaped substrate (300) occurring during the printing process due to the movement of the printing table (210).

5. The printing device (200) according to any one of claims 1 to 4, characterized in that the print head (212) is displaceable perpendicularly with respect to the adjustment movement of the printing table (210) between a maintenance position, in which it lies opposite a cap and can be closed or sealed by the latter, and a printing position, in which it lies opposite the printing table (210) and the web-shaped substrate (300) fixed thereto for printing.

6. The printing device (200) according to any one of claims 1 to 5, characterized in that an alignment unit (226) is arranged directly upstream of the printing area (208), which is configured to align the edges of the substrate (300) with respect to the printing table (210).

7. The printing device (200) according to any one of claims 1 to 6, characterized in that the supply unit (202) is located in a top floor (228), which is located above the printing area (208) in the direction of fall, in that the substrate guidance (206) first guides the web-shaped substrate (300) in the top floor (228) over the printing area (208) before it guides the web-shaped substrate (300) downwards in the falling direction to a middle floor (230), in which the printing area (208) is located, and in that the printed substrate (300) is output in a lower floor in the falling direction below the printing area (208).

8. The printing device (200) according to claim 7, characterized in that the substrate (300) is output on the side on which the supply unit (202) is also located.

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