Ink unit in a printing press for printing on hollow bodies

Abstract

The invention relates to an inking unit in a printing press for printing hollow bodies, comprising an ink application roller mounted on a plate cylinder, an anilox roller mounted on the ink application roller, and an ink distribution system extending in the axial direction of the anilox roller, wherein printing ink is supplied to the ink distribution system from at least one ink reservoir, wherein the ink distribution system is configured to distribute the printing ink supplied from the respective ink reservoir to ink zones arranged in a row in the axial direction of the anilox roller, wherein the ink distribution system comprises several ink metering pumps arranged side by side in the axial direction of the anilox roller, each of which conveys printing ink, wherein each of the ink metering pumps is configured to feed a quantity of the printing ink supplied to the ink distribution system into at least one of the ink zones, and wherein each ink metering pump comprises an ink conveying device.wherein the respective conveying device of the respective ink metering pump is rotaryally driven by an electric motor, wherein a speed of the respective conveying device of the respective ink metering pump, determined by the motor, and thus the quantity of printing ink to be fed into a specific ink zone by the respective ink metering pump, is set by a control unit controlling the respective motor, wherein the control unit is designed such that it sets an individual, time-dependent speed profile for each conveying device of the respective ink metering pumps, depending on a specific production selected or set on the control unit.

Description

[0001] The invention relates to an inking unit in a printing machine for printing on hollow bodies according to the preamble of claim 1.

[0002] As is known, for example, from WO 2012 / 148576 A1, in the packaging industry, several printing units are usually used in a printing press to decorate hollow bodies, each having a cylindrical surface. Each of these printing units transfers one printing ink to a printing blanket used by all of them. The surface of the hollow body is then decorated with a printed motif, for example, in multiple colors, by a relative movement between the surface of the hollow body and the previously inked printing blanket, particularly by rolling the surface of the hollow body across the printing blanket.

[0003] Such a printing machine for printing, i.e., for decorating, hollow bodies, particularly those with a preferably cylindrical outer surface, is used, for example, in conjunction with a production plant, typically comprising several workstations, for the manufacture and further processing of such hollow bodies. Since the printing or decoration of the hollow bodies is carried out by a printing process, these hollow bodies can generally also be referred to as printed products. In such a production plant, the hollow bodies to be printed are manufactured in mass production at, for example, several hundred or even several thousand pieces per minute, e.g., at a rate between 1,500 and 2,500 pieces per minute, particularly preferably at a rate between 1,800 and 2,200 pieces per minute. Such hollow bodies are manufactured, for example, from metal, particularly steel or aluminum, or from a plastic. Such hollow bodies made of metal are, for example,These hollow plastic bodies are used as beverage cans or aerosol cans. Such hollow bodies are manufactured, for example, as thermoplastic molded parts and used, for example, as cups for packaging liquid or pasty foods, especially dairy products or beverages. The hollow body can also be a round tube made of either plastic or aluminum, where a tube is understood to be an elongated, rigid, but malleable container intended for filling with a substance, particularly a paste-like substance. Aluminum tubes are manufactured, for example, using a reverse extrusion process. Plastic tubes are manufactured, for example, by extrusion, always as seamless tubes. Another type of hollow body to be printed on the aforementioned printing press can be preferably cylindrical containers or vessels made of glass, such as bottles or vials.

[0004] The aforementioned WO 2012 / 148576 A1 describes a printing machine, also referred to as a decorator, for decorating cans, wherein an arrangement of several printing units, each with an inking unit, is provided for the multi-color decoration of a large number of cans. Each inking unit belonging to one of the printing units has an ink box for supplying printing ink, wherein each ink box contains an ink roller, also referred to as an ink driver, for receiving the printing ink from the respective ink box. Each inking unit has an ink lifter, wherein the ink lifter receives printing ink from the respective ink roller. In a roller train following the respective ink lifter in the respective inking unit, several color-changing ink-grinder rollers and several ink-transfer rollers, each interacting with at least one of the ink-grinder rollers, are provided.Each inking unit has a plate cylinder with at least one printing plate, with only one inking roller working together with the respective plate cylinder to apply the printing ink.

[0005] When printing or decorating hollow bodies, especially cans, which preferably have a cylindrical outer surface, the trend has recently shifted increasingly towards small production runs. In can printing, this means producing a series of fewer than 100,000 cans, preferably only 50,000 cans or even fewer. Customers expect and demand increasingly customized designs for the printed image, particularly on the outer surface of the hollow body. This necessitates several ink changes at the printing press, i.e., at the decorator's station, per shift. Sometimes, this customer demand results in the inks having to be changed practically hourly at a production speed of between 1,500 and 2,500 cans per minute, preferably between 1,800 and 2,200 cans per minute, because the inks typically require more frequent changes.These are designed as order-specific special colors and therefore differ from one another in color, depending on the production run. A decorator is just one of several workstations in the production line for manufacturing such hollow bodies. Typically, such a production line has a large number of functionally linked workstations, meaning they are coordinated within the production process. It is undesirable for the entire production line, with all its workstations, to come to a standstill to perform a changeover on a decorator due to a production change.Rather, intermediate storage units are provided at various points in the production plant. These units allow the other workstations to temporarily store the workpieces they have processed and which are required for the production of decorated hollow bodies, until the entire production plant is ready for continuous production again after the retooling of a single workstation, such as a decorator. Therefore, the maximum time available for retooling the decorator is practically limited to the period until an intermediate storage unit upstream of the decorator is filled by the continued production of the preceding workstations. This period is, for example, a maximum of 15 to 20 minutes. To enable rapid production changeovers in a production plant of this type, short setup times are therefore essential at the decorator as well.This applies particularly to a printing unit and / or inking unit located in a decorator, whereby it should be noted that such a decorator may have, for example, eight to ten printing units and / or inking units, so that a corresponding number of printing inks may also need to be replaced when changing production. The implementation of a rapid changeover is further complicated by the fact that highly viscous printing inks are used, especially when decorating hollow objects such as cans, i.e., when printing on their respective outer surfaces. Therefore, a printing unit and / or inking unit using these inks is difficult to clean, i.e., requires considerable effort. This is because, due to their viscosity and high pigmentation—i.e., their low flowability and adhesive properties—these printing inks are not easily removed from ink-carrying components.Moreover, the printing inks most commonly used in a decorator, especially the job-specific special colors, are more expensive compared to other printing inks, i.e., standard printing inks or printing inks for other printing processes such as offset printing or gravure printing, so that these highly viscous, especially job-specific, printing inks must be used sparingly for economic reasons alone.

[0006] Printing, in particular on the outer surface of a hollow body, with a multi-colored print motif, i.e., at least one printed image, is preferably carried out using a relief printing process in which printing ink is first applied to a printing blanket and only from there to the outer surface of the hollow body. To carry out this specific relief printing process, a printing plate is arranged on the outer surface of a plate cylinder, which is why this cylinder is sometimes also referred to as a plate cylinder. The printing plate, ready for use in the printing process, is a printing plate with a printed relief, whereby this printed relief represents the printed image intended for the printing process of the indirect relief printing process, in contrast to the classic, i.e.,The direct high-pressure printing process reproduces the image without reflection, whereby, in a trouble-free printing operation, only the printed relief is involved in the transfer of the printing ink supplied to the plate cylinder by the inking unit onto at least one printing blanket interacting with this plate cylinder. The printing plate or printing cliché to be mounted on a plate cylinder has a plate-shaped, preferably flexible, support of finite length, e.g., made of a sheet of steel, on which a particularly flexible printing element is arranged. At least the ends of the support opposite each other in the circumferential direction of the plate cylinder can, for example, be pre-bent or angled according to the curvature of the plate cylinder's outer surface to facilitate easier mounting of the printing plate, i.e., in particular, the printing cliché, on the plate cylinder. The support of the printing plate or printing cliché has a thickness in the range of, for example, 0.2 mm to 0.3 mm.The printing plate, including its substrate, has a total thickness of, for example, 0.7 mm to 1.0 mm, preferably about 0.8 mm. The printing plate is made, for example, of a plastic. To produce the printing plate ready for the printing process, the printing plate is exposed, for example, with a negative film reproducing the print image. The printing areas are then hardened, for example, by means of a laser, and the unexposed areas are subsequently removed from the printing plate, for example, by washing.

[0007] A printing machine, also known as a decorator, for printing or decorating hollow bodies, particularly those with a preferably cylindrical surface, preferably has several, e.g., eight, ten, or even more printing units—also called printing stations—where at least one of these printing units, and in a preferred embodiment all of them, each has a rotatable plate cylinder and an inking unit. The printing units or printing stations, and optionally also the plate cylinders, are each mounted in a frame within this printing machine and can be used in the same printing process to create a multi-colored print motif on the same hollow body, corresponding to the number of printing units or plate cylinders involved. The surface of each plate cylinder typically has aOnly a single printing plate is arranged in each case, the carrier of the printing plate spanning the circumference of the respective plate cylinder completely or at least largely, in particular to more than 80%. The length of the printing plate's printing body in the circumferential direction of the respective plate cylinder is preferably shorter than the circumferential length of the respective plate cylinder. The printing plate or printing plate is, or at least can be, arranged on the lateral surface of each plate cylinder by means of its carrier, preferably magnetically, i.e., the printing plate or printing plate is preferably held there magnetically, i.e., by means of a magnetic holding force.

[0008] In a preferred embodiment, each plate cylinder has a diameter in the range of 100 mm to 150 mm, particularly between 120 mm and 130 mm, wherein the axial length of the respective plate cylinder is, for example, between 200 mm and 250 mm, particularly between 200 mm and 220 mm. The printing plate to be arranged on the outer surface of the respective plate cylinder has a width in the axial direction of the respective plate cylinder in the range of 150 mm to 200 mm, preferably about 175 mm.

[0009] Each of the plate cylinders used in the printing process transfers a specific printing ink to a printing blanket via its printing plate or cliché. The printing inks used are typically premixed, often job-specific, special colors that are specifically tailored to the material of the hollow body being printed, for example, with regard to their printability. This applies whether the surface is made of aluminum, tinplate, or plastic. These job-specific special colors also usually differ in their respective hues. In a preferred embodiment of a printing machine for printing or decorating hollow bodies, each with, for example, a cylindrical surface, a device is provided for transferring the printing ink from the printing plate or cliché to the surface of the hollow body.This ink-transferring device is preferably designed as a segment wheel rotating about a particularly horizontal axis, wherein several printing blankets, e.g., eight, ten, twelve, or even more, are arranged or at least can be arranged one after the other at the periphery of this segment wheel, i.e., along its circumference. The arrangement of the printing blankets on the circumference of the segment wheel is achieved, for example, by attaching the printing blankets to the circumference of the segment wheel, e.g., by a material-bonded connection, preferably by adhesive bonding. The preferably multiple plate cylinders are each radially aligned with, or at least can be aligned with, the printing blankets arranged on the circumference of the respective segment wheel. In a particularly preferred embodiment of a printing machine for printing or decorating hollow bodies, each having, for example, a cylindrical surface – i.e.,of a decorator - a larger number of printing blankets are arranged one after the other along the circumference of the segment wheel than there are plate cylinders radially attached to the segment wheel or at least adjustable to it.

[0010] The preferably carousel-shaped ink transfer device, in particular the segment wheel, has a diameter of, for example, 1,400 mm to 1,600 mm, preferably about 1,520 mm to 1,525 mm, and, with, for example, eight associated plate cylinders, has, for example, twelve printing blankets arranged one behind the other around its circumference. The surface of each printing plate is preferably designed with a greater hardness than the respective surface of the printing blankets. The surface of the printing blankets is preferably flat, i.e., without any profiling. In an operating state in which the plate cylinders involved in the printing process are each radially positioned against the printing blankets of the rotaryally driven segment wheel, the respective printing plates of these plate cylinders, or their respective printing plates, roll on the printing blankets moved by the segment wheel, with the printing plates at least imprinting their print relief into the respective printing blanket.The intensity of the indentation can be adjusted, for example, before or at the beginning of a printing process, e.g. by remote control, by setting a contact force exerted by the relevant plate cylinder on the relevant printing blanket of the segment wheel.

[0011] The printing process for printing, in particular on the outer surface of hollow bodies held, for example, on a mandrel wheel and fed to the segment wheel by means of the mandrel wheel, begins with the application of all printing inks required for the image to be printed on the outer surface of the hollow body, for example, from the respective printing cliché of the plate cylinders attached to the segment wheel, to the same surface by one of the printing blankets arranged on the circumference of the segment wheel. The printing blanket, thus inked with all the necessary printing inks, then transfers these inks simultaneously to the outer surface of the hollow body to be printed during a single rotation of the hollow body around its longitudinal axis while it is held on the mandrel wheel.During the transfer of the printing inks from the printing blanket to the surface of the hollow body, the hollow body to be printed, held, for example, by the mandrel wheel, rotates at a circumferential speed equal to that of the printing blanket, which is arranged, for example, on the circumference of the segment wheel. The respective circumferential speeds of the hollow body and the printing blanket or segment wheel are therefore synchronized, with the hollow body to be printed, held, for example, on the mandrel wheel, being accelerated, in particular, by a drive means, from a standstill, especially until it reaches the circumferential speed of, for example, the segment wheel. In the preferred embodiment, the segment wheel carrying the printing blanket determines the circumferential speed to be set, for example, on the mandrel wheel. The circumferential speed of the plate cylinder carrying the printing plate or printing cliché is also preferably dependent on the circumferential speed, for example, of the segment wheel.of the segment wheel. In the preferred embodiment, the mandrel wheel and the segment wheel are each driven individually by their own drive and their respective rotational behavior is controlled or regulated by a control unit.

[0012] As previously mentioned, hollow bodies such as cans are printed with highly viscous inks. This means that the inks used in a decorator have a dynamic viscosity between 2 Pa*s and 40 Pa*s at 20°C, making them quite viscous and significantly less fluid compared to inks used in other printing processes, such as offset printing. A preferred range for the dynamic viscosity of inks used in a decorator at 20°C is between 6 Pa*s and 10 Pa*s. Inks with lower dynamic viscosity are less viscous but tend to splash during application to the hollow bodies, creating overspray. This overspray unacceptably contaminates at least the decorator's inking unit and its immediate surroundings.This contamination impairs subsequent production processes carried out by the decorator, for example, by allowing printing ink from a previous printing process to be carried over. Such highly viscous printing ink is heavier than water and has a density, for example, in the range of 1.1 kg / dm³. 3 and 1.2 kg / dm³ 3 and is formed as a wet layer in hollow aluminum bodies, e.g. with up to 1.2 g / m² 2 and for hollow bodies made of steel, e.g., up to 1.8 g / m³ 2 applied to their respective lateral surface.

[0013] Printing inks are generally very complex mixtures. It has been observed that highly viscous printing inks, for example, tend to block in an inking unit due to their high proportion of color pigments and / or their high proportion of long-chain polymers, as a result of their polymerization, i.e., a progressive curing process. To keep these printing inks flowable despite their tendency to polymerize, attempts have been made in practice to keep such inks constantly agitated. This agitation can be done manually by an operator at the decorator or mechanically by an agitator located in or at least in conjunction with the inking unit.While stirring improves the flowability of the printing ink, the resistance of the stirred ink to the shear stress exerted by the stirring generates frictional heat. This can cause the ink to heat up locally to temperatures of up to 80°C, particularly during a multi-hour printing process. Such a high temperature, however, undesirably promotes and accelerates the polymerization of the ink. Furthermore, this high temperature not only alters the rheological properties of the ink but can also cause it to change in color, no longer accurately reproducing the intended hue. This is completely unacceptable, as printing inks must be consistently color-accurate and as stable as possible throughout the entire printing process.For example, white printing ink can turn gray after heating and become unusable because no customer would accept this color change for their commissioned printed product. Blocked and / or color-altered inks, such as those affected by unwanted heating, are therefore no longer usable and certainly cannot be reused in a subsequent printing process. Given the generally high procurement costs of these high-viscosity printing inks, this has an extremely negative impact on the profitability of the printing process carried out by a decorator and can even preclude their use altogether.

[0014] German patent DE 10 2019 123 631 A1 discloses an inking unit of a printing press, particularly one designed as a decorator, comprising at least one ink reservoir, an anilox roller, a doctor blade chamber, and an ink pump with a pump housing. A motor rotating to drive the ink pump is located outside the pump housing. The pump housing is designed as an interchangeable unit within the inking unit, independently of the motor. This interchangeable unit is detachable from both the inking unit and the ink pump motor, and thus preferably replaceable without tools. The ink to be pumped by the ink pump has a dynamic viscosity at 25°C, preferably in the range of 5 Pa*s to 75 Pa*s.

[0015] DE 10 2019 123 634 A1 discloses an ink agitator for circulating printing ink in an ink tray arranged in an inking unit of a printing press, comprising an agitator, wherein the agitator is moved or at least movable bidirectionally by a drive along the longitudinal extent of the ink tray, wherein a frequency of the working cycles performed by the agitator is set depending on the viscosity of the printing ink arranged in the ink tray and / or wherein the frequency of the working cycles performed by the agitator is set differently for different printing inks.

[0016] German patent DE 298 20 075 U1 discloses an inking unit with an ink tray, wherein the ink tray is equipped with a screw conveyor and an ink pump. This ink pump preferably has its own drive, for example an electric motor; however, it can also be connected via coupling means to the drive of the printing press or the inking unit, provided the latter has its own drive. Within the ink tray, the printing ink is transported by a screw conveyor, which in turn is driven by a motor. The screw conveyor transports the printing ink towards the ink pump.

[0017] US Patent 5,280,750 A also discloses a paint plant with a paint tray, the paint tray being equipped with a screw conveyor and a paint pump.

[0018] DE 691 17 645 T3 discloses a dye works with a dye reservoir, wherein a screw conveyor is arranged in the dye reservoir.

[0019] DE 196 24 440 A1 discloses an inking unit with an anilox roller and a doctor blade device.

[0020] DE 110 081 T1 discloses an inking unit for a rotary printing press with printing rollers, printing cylinders and inking rollers, comprising: a) a feed roller, b) an ink supply rail adjacent to the feed roller, which is movable between an operating position in which ink can be applied to the feed roller and a rest position in which this is not the case, wherein the ink supply rail is provided with spring-loaded means projecting from it, which smooth the surface of the ink applied to the surface of the feed roller without affecting the metering, and c) an ink metering pump, which is connected to an ink source and to the ink supply rail and dispenses metered quantities of ink to the ink supply rail for subsequent uniform application to the feed roller.

[0021] The invention is based on the objective of creating an inking unit in a printing press for printing hollow bodies. This inking unit should be able to print a highly viscous printing ink with a dynamic viscosity, particularly in the range between 2 Pa*s and 40 Pa*s, wherein this printing ink is kept permanently flowable by a suitable design of the inking unit, and the rheological properties of this printing ink remain at least virtually unchanged during the printing process, and wherein the color of the printing ink in question also remains stable during an ongoing printing process.

[0022] The problem is solved according to the invention by the features of claim 1. The dependent claims relate to advantageous embodiments and / or further developments of the solution found.

[0023] The advantages achievable with the invention lie particularly in the fact that the inking unit is designed in such a way that the printing ink is kept permanently fluid within it, and the rheological properties of this printing ink remain at least virtually unchanged during the printing process, and the color tone of the respective printing ink also remains stable during the printing process. This allows any residual printing ink to be reused in a subsequent printing process. Ideally, no residual ink remains at all, since all the ink introduced into the inking unit is also printed. Furthermore, keeping the printing ink fluid within the inking unit facilitates cleaning of this unit, for example, when changing production processes. The proposed inking unit is designed in such a way that the application of shear forces to the printing ink is minimized and unavoidable shear forces do not act on the printing ink for extended periods.

[0024] The proposed inking unit is designed to allow for zonal, very finely metered ink supply. The ink metering pumps used for this purpose are controlled, or at least controllable, according to the specific print image being produced. The amount of ink supplied to the respective ink zones by the metering pumps is largely consumed, i.e., absorbed by the anilox roller and not circulated in a closed loop.

[0025] Further advantages will become apparent from the following description.

[0026] An embodiment of the invention is shown in the drawing and is described in more detail below.

[0027] They show: Fig. 1 a printing machine for printing or decorating hollow bodies, each having a surface; Fig. 2 a dye works in the Fig. 1 printing press shown; Fig. 3 a part of a color distribution system of the in the Fig. 2 depicted dye works; Fig. 4 a micro gear pump.

[0028] Fig. Figure 1 shows a simplified and exemplary schematic representation of a printing machine for printing or decorating hollow bodies 01, e.g., two-part cans, each having a preferably cylindrical outer surface. These hollow bodies 01 are sequentially fed by a conveying device to a transport device designed as a mandrel wheel 02 and are individually held by a holder on this transport device. The conveying direction is shown in the Fig. 1 indicated by a directional arrow. The mandrel wheel 02 interacts with a printing ink transfer device designed as a rotating or at least rotatable segment wheel 03, wherein several printing blankets 07 are arranged one behind the other along the circumference of this segment wheel 03. The respective direction of rotation of the mandrel wheel 02 and the segment wheel 03 are shown in the Fig. 1, each indicated by a direction-of-rotation arrow. Along the circumference of the segment wheel 03, several plate cylinders 04 are arranged radially to, or at least adjustable to, this segment wheel 03. A printing plate, in particular a printing cliché, is arranged on the respective surface of each of these plate cylinders 04, and this printing cliché is designed, in particular, for carrying out a relief printing process. A specific printing ink is supplied to each of the plate cylinders 04 by means of an inking unit 06 for the purpose of inking its printing plate or printing cliché.

[0029] An inking unit 06 involved in the printing process receives the printing ink to be printed via an ink-carrying line system 34 from an ink reservoir 33. This ink reservoir 33 can be, for example, a commercially available ink container provided at the printing press, or a central ink supply tank provided in the printing plant, i.e., assigned to the printing press, or an ink tray located in the printing press and filled with printing ink, e.g., manually. Each of the inking units 06, arranged on the circumference of the segment wheel 03 and each connected to or at least connectable to one of the plate cylinders 04, prints, for example, a different printing ink, these printing inks differing from one another, particularly in their respective hues.The printing ink used in a high-pressure printing process is highly viscous, meaning that the respective printing ink has a dynamic viscosity at 20°C, particularly in the range between 2 Pa*s and 40 Pa*s, and sometimes even up to 60 Pa*s. This highly viscous, and therefore only viscous, printing ink is supplied to the relevant inking unit 06 from the relevant ink reservoir 33 via the piping system 34 at a pre-pressure in the range between 2 bar and 10 bar, preferably between 6 bar and 8 bar. The ink-carrying piping system 34 is, for example, formed by a rigid pipe and / or by a flexible hose connection.

[0030] Each of the 06 color works is - as in a longitudinal section view of the Fig. 2. This is shown in an exemplary and simplified manner – preferably each unit is designed as a short inking unit, meaning that its roller assembly, which transports the printing ink to the plate cylinder 04, consists only of an anilox roller 08 and a single inking roller 09. The anilox roller 08, with depressions on its outer surface, e.g., in the form of cells, receives printing ink supplied to the respective inking unit 06 from the ink reservoir 33 and transfers this printing ink to the inking roller 09, which interacts directly with the anilox roller 08. The inking roller 09 is positioned against the plate cylinder 04 to be inked during an ongoing printing process. In the preferred embodiment, the plate cylinder 04 and the inking roller 09 have the same diameter D.The plate cylinder 04, the inking roller 09, and the anilox roller 08 each have their own electric drive, i.e., a motor M, for their respective rotational movement, each controlled or regulated by a control unit 28, which is primarily digital. This control unit 28 can, for example, be located in a control room belonging to the printing press.

[0031] Advantageously, a color-changing overprinting roller 11 and, for example, a similarly color-changing rider roller 12 are attached to the anilox roller 08 to ensure uniform ink uptake. The overprinting roller 11 preferably has a rubberized surface. A color-changing overprinting roller 13 is also preferably attached to the ink application roller 09 to further ensure uniform ink application. The respective stroke frequency of the color-changing rollers 11, 12, and 13 is preferably variably set or at least adjustable on the control unit 28, which advantageously controls various functions of the inking unit 06, up to a maximum stroke frequency of, for example, 2 Hz. The axial stroke resulting from the color-changing movement of the aforementioned rollers 11, 12, and 13 extends, for example, over a range between 10 mm and 50 mm. The direction of rotation of the roller 11 is determined by the control unit 28, which advantageously controls various functions of the inking unit 06. Fig. The segment wheel 03, only partially shown, and the respective direction of rotation of the plate cylinder 04, the anilox roller 08, the ink application roller 09, the ink overprinting rollers 11; 13 and the rider roller 12 are shown in the Fig. 2 each indicated by a direction arrow.

[0032] Advantageously, a washing device 14 with a doctor blade is also arranged in the periphery of the anilox roller 08, wherein the doctor blade can be positioned against the respective anilox roller 08, for example, during a production change involving a color change. The anilox roller 08 also has, for example, a temperature control device 31 whose outer surface is provided with a specific temperature, wherein this temperature control device 31 has channels 23 arranged inside the anilox roller 08 extending in its axial direction, and wherein these channels 23 are supplied with a temperature control fluid. This temperature control fluid is, for example, water, preferably with a temperature in the range between 15°C and 25°C, in particular between 17°C and 22°C, wherein the temperature control device 31 is designed such that it adjusts the temperature of the water starting from, for example, a specific temperature.The control unit 28 maintains a constant setpoint temperature within the range of 15°C to 25°C, with a tolerance of ±1°C. By controlling the temperature of the outer surface of the anilox roller 08, the viscosity of the printing ink transported by this roller 08 is influenced. The aim is to keep the ink flowable while simultaneously preventing both clogging of the inking unit 06 and ink spatter.

[0033] Fig. Figure 2 shows a cross-section of a holder 16 extending axially along the anilox roller 08, for example in the form of a crosshead, to which a doctor blade 17 is attached. The doctor blade 17 is positioned against the outer surface of the anilox roller 08, particularly with a slight mechanical preload, or at least adjustable. It is arranged tangentially to the outer surface of the anilox roller 08 and applies printing ink to the outer surface of the anilox roller 08 in at least one of the ink zones. The doctor blade 17 is positioned against the outer surface of the anilox roller 08 with an adjustable, particularly low, contact pressure and is located, for example, between the holder 16 and a cover plate 18 attached to the side of the holder 16 facing the anilox roller 08.At least one ink metering pump 21 is arranged on the side of the holder 16 facing away from the anilox roller 08. The ink-conveying conveying unit of this pump is rotaryally driven by an electric motor 19. The motor 19, preferably a stepper motor, rotates the ink-conveying conveying unit of the ink metering pump 21 within a speed range from standstill to, for example, 200 rpm. This speed is preferably variably adjustable and set at the control unit 28. A preferred speed range is between 70 rpm and 100 rpm. For conveying very small quantities of ink, a stop-and-go operation of the ink-conveying conveying unit of the ink metering pump 21 is also possible, with the operating sequences being flexibly definable in this mode.The control unit 28 is designed to set an individual, time-dependent speed profile for the respective conveying unit of the ink metering pump 21, depending on a specific production process selected or set on the control unit 28. This means that the speed of the ink conveying unit of the respective ink metering pump 21 is adjusted as needed over time, according to the quantity of ink to be supplied by the ink metering pump 21 to the doctor blade 17. The quantity of ink to be supplied to the doctor blade 17 is determined, for example, densitometrically from a printing template before a specific printing process is carried out, with the data thus determined being transmitted to the control unit 28 and converted there into a specific quantity of ink.This prevents over-inking of the hollow bodies 01 to be printed. The control unit 28 is also designed such that the respective, i.e., previously set, speeds of all ink metering pumps 21 of the respective inking unit 06 can be changed simultaneously and in equal increments. Therefore, the control unit 28 allows all ink metering pumps 21 of a specific inking unit 06 to be individually adjusted in their respective speed profiles, thus according to the ink requirements in the individual color zones. Furthermore, adjustments to the speed behavior of all ink metering pumps 21 can also be made simultaneously and in the same manner.

[0034] The quantity of printing ink to be fed into the respective ink zone by the ink metering pumps 21 is preferably guided orthogonally to the doctor blade 17. The conveying device of the respective ink metering pump 21 has an inlet 22, arranged, for example, at the upper end of the holder 16, for printing ink supplied to the inking unit 06 from an ink reservoir 33, wherein this inlet 22 is connected or at least connectable to the ink-carrying piping system 34. A barrier filter is preferably arranged in the ink-carrying piping system 34 and / or in the inlet 22, which prevents solid particles with a size greater than 10 µm, transported in or with the printing ink, from entering the conveying device of the respective ink metering pump 21. This prevents malfunctions in a very finely metering ink distribution system. The holder 16 with the doctor blade 17 and, as a rule,The cover plate 18 and the at least one ink metering pump 21 flanged to the holder 16 and driven by the motor 19 form, with reference to the respective inking unit 06, the respective ink distribution system arranged or at least arrangable on the respective anilox roller 08.

[0035] Fig. Figure 3 shows a part of the structure in a perspective view. Fig. 2. The ink distribution system comprises a doctor blade 17, which is held by a holder 16 on its side facing the anilox roller 08 and extends longitudinally to the anilox roller 08 over at least one ink zone, preferably over several, e.g., over three ink zones, and an ink distribution bar 24, preferably arranged at the upper end of the holder 16, wherein at least one ink metering pump 21, preferably several, e.g., three ink metering pumps 21, are arranged side by side, each with its motor 19, on the rear side, i.e., on the side of the holder 16 facing away from the anilox roller 08. In a preferred embodiment, a single ink zone extends longitudinally to the anilox roller 08, e.g., over a width in a range between 20 mm and 60 mm, preferably 40 mm or 50 mm. In an advantageous embodiment of the inking unit 06, several, e.g.,Three to six ink zones are arranged side by side along the anilox roller 08, these ink zones preferably being of the same width. However, if several ink zones are arranged side by side along the anilox roller 08, they can also be of different widths if required. Furthermore, it can be provided that several holders 16 are arranged side by side along the anilox roller 08. A cover plate 18 is typically arranged on the front of the respective holder 16, i.e., on its side facing the anilox roller 08. Fig. 2), which in the Fig. Figure 3 is not shown for a better understanding of the ink distribution system. The printing ink supplied from the ink reservoir 33 via the inlet 22 of the ink distribution bar 24 is guided inside this ink distribution bar 24 in channels and / or grooves and first fed to the respective delivery unit of at least one of the ink metering pumps 21. The delivery unit of the respective ink metering pump 21 is controlled by the control unit 28 such that a precisely determined quantity of printing ink is fed into a specific ink zone. The ink distribution system is therefore designed such that it feeds the printing ink supplied to it from the respective ink reservoir 33 in a quantity determined by the control unit 28 into at least one ink zone or distributes it among several ink zones arranged in the axial direction of the anilox roller 08.It can also be provided that different printing inks from different ink reservoirs 33 are supplied to the ink distribution system for the execution of a specific printing process, with the ink distribution system being designed to feed these different printing inks into separate color zones. An advantage of this ink distribution system design is that only the color zones required for the respective printing process are actually supplied with printing ink, thus ensuring that the inking unit 06 is supplied with the precise amount of printing ink in the required dosage and at the exact position required.

[0036] Fig. Figure 3 shows by way of example several ink outlet openings 26 formed in connection with the ink distribution bar 24, from each of which a quantity of printing ink measured by the conveying device of one of the respective ink metering pumps 21 exits, wherein this printing ink is supplied to at least a certain ink zone via a shaped piece 27 preferably wedge-shaped in or on the holder 16, wherein the shaped piece 27 widens from the respective ink outlet opening 26 towards the doctor blade 17 parallel to the axial direction of the anilox roller 08.

[0037] The at least one ink metering pump 21 is preferably designed as a micro gear pump. A minimum flow rate delivered by its pumping unit is, for example, 0.004 l / h. A maximum flow rate delivered by its pumping unit is, for example, 2.5 l / h. The ink metering pump 21 is preferably designed such that, even in continuous operation for, for example, 20 hours per working day, at a pre-pressure at the ink distribution bar 24 in a range of, for example, 2 bar to 10 bar, it delivers a quantity of printing ink in the range between its minimum and maximum flow rates, wherein this printing ink has a dynamic viscosity in the range between 2 Pa*s and 40 Pa*s at 20°C.A specific pre-pressure of the printing ink conveyed in the line system 34 must be present at the ink distribution bar 24, which is connected to the respective ink reservoir 33 and extends longitudinally to the anilox roller 08, preferably over several ink zones, in order to ensure precise metering of the printing ink distributed to the respective ink zones by the respective ink metering pumps 21. Advantageously, a pressure sensor 29 is arranged at the inlet 22 or in the ink distribution bar 24 to detect the pre-pressure of the printing ink conveyed in the line system 34. A flow direction of the printing ink conveyed in the line system 34 is specified in the... Fig. 2 indicated by directional arrows. The pressure sensor 29, which detects the pre-printed pressure, transmits its measurement data to the control unit 28. Depending on the measurement data from this pressure sensor 29, the control unit 28 then controls the quantity of printing ink to be drawn from the relevant ink reservoir 33 and supplied to the ink distribution system. The quantity of printing ink to be drawn from the relevant ink reservoir 33 is supplied to the ink distribution system, for example, by at least one pump 32, controlled by the control unit 28, which delivers printing ink in the piping system 34.

[0038] Fig. Figure 4 shows an exemplary cross-sectional view of the construction of a micro annular gear pump. A micro annular gear pump is a rotary positive displacement pump and has an inlet opening 36 on its suction side and an outlet opening 39 on its pressure side for the printing ink to be metered and conveyed. A preferably cylindrical housing contains an internally toothed outer rotor 37 and an externally toothed inner rotor 38. The outer rotor 37 and the inner rotor 38 are mounted eccentrically to each other and each has a cycloidal tooth pattern, with their two tooth patterns meshing. During rotation of the aforementioned rotors 37 and 38, their two tooth patterns form a system of several sealed conveying chambers at all times. The inner rotor 38 has one fewer tooth than the outer rotor 37. With a tooth ratio of, for example, six teeth on the inner rotor 38 to six on the outer rotor 38, the inner rotor 38 has a significantly smaller tooth profile. B. seven teeth on the outer rotor 37 - as in the Fig. Figure 4, shown as an example, results in a chamber count of six. A shaft of the micro annular gear pump is torsionally rigidly connected to the inner rotor 38 and is driven by the electric motor 19 belonging to the respective micro annular gear pump, wherein this motor 19, preferably designed as a stepper motor, is precisely controlled by the control unit 28. The outer rotor 37 is rotatably mounted on its circumference and is driven by the inner rotor 38. Through the rotation of the rotors 37; 38 about their offset axes – in the Fig. As indicated by crosses, the pumping chambers on the suction side enlarge while simultaneously decreasing in size on the pressure side. Between the kidney-shaped inlet opening 36 and outlet opening 39, each connecting several pumping chambers, a uniform and low-pulsation flow is thus created. The pumping direction of the micro annular gear pump is reversible, although a preferred direction of rotation exists. Fig. In figure 4, the direction of rotation chosen here as an example is indicated by a direction arrow. Reference symbol list 01 Hollow body 02 Mandrel wheel 03 Segment wheel 04 Plate cylinders 05 - 06 Dye Works 07 Printing blanket 08 Anilox roller 09 Ink application roller 10 - 11 Paint rubbing roller 12 Rider roller 13 Paint rubbing roller 14 Washing facilities 15 - 16 holders 17 squeegee blades 18 Cover plate 19 engine 20 - 21 Paint dosing pump 22 Inflow Channel 23 24 color distribution strip 25 - 26 Color outlet opening 27 Fitting 28 Control unit 29 Pressure sensor 30 - 31 Temperature control unit 32 Pump 33 Color reservoir 34 Pipeline system 35 - 36 Entrance opening 37 Outer rotor 38 Inner rotor 39 Outlet opening D Diameter M engine QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2012 / 148576 A1 [0002, 0004] DE 10 2019 123 631 A1

[0014] DE 10 2019 123 634 A1

[0015] DE 298 20 075 U1

[0016] US 5,280,750 A

[0017] DE 691 17 645 T3

[0018] DE 196 24 440 A1

[0019] DE 110 081 T1

[0020]

Claims

[1] An inking unit (06) in a printing press for printing hollow bodies (01), comprising an ink form roller (09) mounted on a plate cylinder (04) and an anilox roller (08) mounted on the ink form roller (09), and comprising an ink distribution system extending in the axial direction of the anilox roller (08), wherein printing ink is supplied to the ink distribution system from at least one ink reservoir (33), wherein the ink distribution system is designed to distribute the printing ink supplied from the respective ink reservoir (33) to ink zones arranged next to one another in the axial direction of the anilox roller (08), wherein the ink distribution system comprises a plurality of ink metering pumps (21) arranged side by side in the axial direction of the anilox roller (08), each of the ink metering pumps (21) being designed to feed a quantity of the printing ink supplied to the ink distribution system into at least one of the ink zones,wherein each ink metering pump (21) has a conveyor device for conveying printing ink, wherein the respective conveyor device of the respective ink metering pump (21) is rotatably driven by an electric motor (19), wherein a speed of the respective conveyor device of the respective ink metering pump (21) and thus the quantity of printing ink to be fed into a specific ink zone by the respective ink metering pump (21) is determined by the motor (19) and is set by a control unit (28) controlling the respective motor (19), wherein the control unit (28) is designed such that it sets an individual time-dependent speed curve for each conveyor device of the respective ink metering pumps (21) depending on a specific production selected or set on the control unit (28). [2] Inking unit (06) according to claim 1, characterized bythat the motor (19) which rotatably drives the conveyor device conveying the printing ink is designed as a stepper motor and / or that this motor (19) is set to a speed in a speed range starting from standstill up to a speed of 200 rpm and / or that this motor (19) is operated in a stop-and-go mode, wherein the operating sequences can be flexibly defined in this mode of operation [3] Inking unit (06) according to claim 1 or 2, characterized by in that the ink distribution system is designed to cooperate with a doctor blade (17) extending in the axial direction of the anilox roller (08), wherein the doctor blade (17) is designed to apply printing ink to a circumferential surface of the anilox roller (08) in at least one of the inking zones, wherein the doctor blade (17) is arranged tangentially to the circumferential surface of the anilox roller (08). [4] Inking unit (06) according to claim 3, characterized bythat the quantity of printing ink to be fed into the respective ink zone by the ink metering pumps (21) is guided orthogonally against the doctor blade (17). [5] Inking unit (06) according to claim 3 or 4, characterized by that the doctor blade (17) is designed to extend over several ink zones, wherein a single ink zone extends longitudinally to the anilox roller (08) over a width in a range between 20 mm and 60 mm. [6] Inking unit (06) according to claim 3 or 4 or 5, characterized by in that the ink distribution system has an ink distribution bar (24) connected to the relevant ink reservoir (33), said ink distribution bar (24) extending longitudinally to the anilox roller (08) over a plurality of ink zones, wherein a plurality of ink outlet openings (26) are formed in or on the ink distribution bar (24), from each of which an amount of printing ink measured by the conveying device from one of the relevant ink metering pumps (21) emerges. [7] Inking unit (06) according to claim 6, characterized by that at least one wedge-shaped shaped piece (27) is provided, wherein the printing ink emerging from the ink outlet openings (26) is supplied to at least one specific ink zone via at least one of the wedge-shaped shaped pieces (27), wherein the shaped piece (27) in question widens from the ink outlet opening (26) in question to the doctor blade (17) parallel to the axial direction of the anilox roller (08). [8] Inking unit (06) according to claim 6 or 7, characterized by that a pressure sensor (29) detecting the pre-pressure of the printing ink is arranged in the ink distribution bar (24) or on an inlet (22) to the ink distribution system connected to the relevant ink reservoir (33) via a line system (34), said pressure sensor (29) reporting its measurement data to the control unit (28). [9] Inking unit (06) according to claim 8, characterized bythat the control unit (28) is designed to control the amount of printing ink to be taken from the relevant ink reservoir (33) and fed to the ink distribution system as a function of the measurement data of this pressure sensor (29). [10] Inking unit (06) according to claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9, characterized by that the control unit (28) is designed in such a way that the previously set speeds of all ink metering pumps (21) of this inking unit (06) can be changed jointly and in equal steps in addition to the individual setting.

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