DE102022114616A1 - Inking unit of a device for printing hollow bodies - Google Patents

Abstract

The invention relates to an inking unit of a device for printing hollow bodies, comprising an anilox roller and a squeegee chamber which interacts with the anilox roller, an ink pump conveying printing ink from an ink tray through the squeegee chamber being provided, the ink pump being rotatably driven by a drive, from which Printing ink not picked up by the anilox roller is returned to the ink tray, wherein in the ink tray a printing ink is arranged from a return of the squeegee chamber to a suction point of the ink pump conveying transport screw, the ink pump being arranged at a first end of the transport screw on a first end face of the ink tray and wherein the The drive rotating the paint pump is arranged at a second end of the transport screw on a second end face of the paint tray.

Description

The invention relates to an inking unit of a device for printing hollow bodies according to the preamble of claim 1.

Such as B. from the WO 2012/148576 A1 As is known, several printing units are usually used in the packaging industry in a device for decorating hollow bodies each having a cylindrical lateral surface. Each of these printing units transfers one printing ink to a printing blanket used jointly by these printing units. The lateral surface of the hollow body in question is then formed by a relative movement between the lateral surface of the hollow body in question and the printing blanket, which has previously been colored in particular in multiple colors, in particular by rolling the lateral surface of the hollow body in question on this printing blanket, with a z. B. decorated with a multi-colored print motif.

Such a device for printing or decorating hollow bodies, in particular each having a preferably cylindrical lateral surface, is used, for example. B. used in conjunction with a production system that usually has several work stations for the production and further processing of such hollow bodies, the printing or decoration of the hollow bodies being carried out by a printing process, which is why these hollow bodies can also generally be referred to as printed products. In such a production system, the hollow bodies to be printed are mass-produced with e.g. B. several hundred or even a few thousand pieces per minute, e.g. B. between 1,500 and 2,500 pieces per minute, particularly preferably between 1,800 and 2,200 pieces per minute. Such hollow bodies are z. B. made of metal, especially steel or aluminum, or made of a plastic. Such hollow bodies made of metal are z. B. used as beverage cans or as aerosol cans.

Such hollow bodies made of plastic are z. B. produced in the form of thermoplastic moldings and z. B. as a cup for packaging e.g. B. used by liquid or pasty foods, especially dairy products or drinks. The respective hollow body can also be a round tube body made of either plastic or aluminum, a tube being understood to mean an elongated, solid but malleable container which is intended to be filled with a particularly pasty substance. Tubes made of aluminum are used e.g. B. produced in a reverse extrusion process. Plastic tubes are used e.g. B. produced as seamless tubes by extrusion. Another type of hollow bodies to be printed in an aforementioned device can be containers or vessels made of glass, preferably cylindrical, e.g. B. bottles or flacons.

Beverage cans are preferably made of aluminum and are usually so-called two-part cans, in which a circular base together with a preferably straight cylinder jacket are each made from a single workpiece, i.e. H. from a so-called slug or from a blank, i.e. H. a circular disc, in a forming process, e.g. B. in a cold extrusion process or in a tensile pressure forming process, preferably by deep drawing, in particular by deep drawing, to form a hollow body open on one side, i.e. H. are manufactured into a so-called raw can and in a manufacturing step carried out at the end of production, a circular lid is placed on the cylinder jacket and connected to the cylinder jacket in an airtight manner by flanging.

Another type of can are tin cans. Tinplate is a tinned sheet of steel. For the production of tinplate cans, the thickness of the steel sheet is e.g. B. 0.15 mm to 0.49 mm, the thickness of the tin layer z. B. 0.2 µm to 0.8 µm, with the tin coating serving as corrosion protection. Tinplate cans are so-called three-part cans. To produce the jacket of a tinplate can, a rectangular strip of sheet steel is bent into a preferably straight cylindrical jacket, the ends of this strip, which is bent into a cylindrical jacket, being welded in a butt joint. A circular base and a circular lid are then placed on the cylinder jacket and the edges are flanged. In order to obtain greater resistance to indentation for the tinplate can in question, e.g. B. all three parts, i.e. H. the cylinder jacket, the base and the lid preferably have a wave profile.

An aerosol can, also known as a spray can or aerosol can, is a metal can used to spray liquids. In an aerosol can, the filled liquid is under pressure, with z. B. propane, butane, dimethyl ether or mixtures thereof or compressed air or nitrogen is used.

The aforementioned WO 2012/148576 A1 describes a device for decorating cans, wherein an arrangement of several printing units, each with an inking unit, is provided for multi-colored decoration of a large number of cans. Each of the inking units belonging to one of the printing units each has an ink fountain for providing printing ink, with in Each ink fountain is provided with an ink fountain roller for receiving the printing ink from the relevant ink fountain. An ink ductor is provided in each inking unit, the ink ductor each receiving printing ink from the relevant ink fountain roller, with a plurality of iridescent ink rollers and several ink transfer rollers each interacting with at least one of the ink ductor rollers being provided in a roller train following the respective ink ductor in the relevant inking unit. For each inking unit there is a plate cylinder with at least one printing plate, with only a single inking roller working together with the respective plate cylinder to apply the printing ink.

Furthermore, through the WO 2011/051072 A1 a printing unit of a printing machine, in particular an offset printing machine, having an ink supply with a highly viscous printing ink with a viscosity in the range z. B. between 10 Pa*s and 150 Pa*s, an anilox roller, a chamber doctor blade, an ink pump and a z. B. arranged in a collecting container stirring device, this stirring device z. B. is designed as a rod that can be rotated about its longitudinal axis or alternatively spiral, helical or propeller-like. It is not necessarily the task of the stirring device to take part in the actual transport process of the printing ink, but rather the stirring device serves to bring the printing ink into an advantageous state, particularly with regard to its viscosity, and/or to keep it in this state.

Through the DE 10 2019 123 631 A1 an inking unit of a printing press designed in particular as a decorator is known, having at least one container for providing printing ink, an anilox roller, a doctor chamber and an ink pump with a pump housing, with a motor rotating the ink pump being arranged outside the pump housing, the pump housing as a changing unit that can be replaced in the inking unit independently of the motor is formed, this changing unit being detachable from the inking unit and the motor of the ink pump and therefore preferably interchangeable without tools. The printing ink to be conveyed by the ink pump has a dynamic viscosity at 25° C., preferably in the range from 5 Pa*s to 75 Pa*s.

Through the DE 10 2019 123 634 A1 an ink agitator for circulating printing ink in an ink tray arranged in an inking unit of a printing press is known, with an agitator element, the agitator element being moved or at least movable bidirectionally by a drive along the longitudinal extent of the ink tray, with a frequency of the work cycles carried out by the agitator element being dependent is set by the viscosity of the printing ink arranged in the ink tray and/or the frequency of the work cycles carried out by the stirring element is set differently for different printing inks.

When printing or decorating hollow bodies, in particular cans, which each have a preferably cylindrical outer surface, the trend is increasingly towards small production, which in can printing means the production of a series of fewer than 100,000 cans, preferably even just 50,000 cans or even fewer Number of doses means. Customers expect and demand an increasingly individual design of the printed image to be applied, particularly on the lateral surface of the hollow body in question. This requires several changes of printing colors on the printing press, ie on the decorator, per work shift. Sometimes this customer request means that at a production speed of between 1,500 and 2,500 pieces (cans) per minute, preferably between 1,800 and 2,200 pieces (cans) per minute on the printing machine, the printing colors have to be changed practically every hour because the printing colors are usually order-specific Special colors are designed and are therefore e.g. B. differ in color depending on production. Now a decorator is just one of several work stations in the production facility for producing such hollow bodies. Such a production system usually has a large number of work stations that are functionally linked to one another, that is to say that they are coordinated with one another in the production process. It is not desirable for the entire production system with all its work stations to come to a standstill in order to carry out a conversion on a decorator due to a production change. Rather, a buffer store is provided at various points in the production system, in which the remaining work stations can temporarily store the workpieces they have processed and required for the production of decorated hollow bodies until the entire production system is ready for production again after an individual work station such as a decorator has been converted . In practice, the only time available for converting the decorator is until a buffer located upstream of this decorator is filled by the continued production of upstream work stations. This period is e.g. B. at most 15 to 20 minutes. In order to be able to realize rapid production changes in a production system of this type, short set-up times are also essential for a decorator. This also applies in particular to a printing unit arranged in a decorator and/or Inking, whereby it should be noted that such a decorator e.g. B. has eight to twelve printing units and / or inking units, so that when there is a change in production, a corresponding number of printing inks may also have to be replaced. The realization of a quick conversion is made even more difficult by the fact that, especially when decorating hollow bodies, such as. B. cans, ie particularly when printing their respective lateral surface, highly viscous printing inks are used, so that an inking unit and/or printing unit using these printing inks is difficult to clean, ie with increased effort. Because of their toughness, i.e. low flowability and adhesive properties, these printing inks cannot be easily removed from ink-carrying components. In addition, the most commonly used printing colors, ie the order-specific special colors, compared to other printing colors, ie standard printing colors or printing colors for other printing processes such as. B. offset printing is quite expensive, so that these order-specific printing inks have to be used sparingly for economic reasons and it is forbidden to simply dispose of remaining stocks in the inking unit instead of collecting them and reusing them in later production.

The invention is based on the object of creating an inking unit of a device for printing hollow bodies, in particular an ink supply of this inking unit meeting the requirement for short changeover times.

The object is achieved according to the invention by the features of claim 1. The dependent claims relate to advantageous refinements and/or further developments of the solution found.

The advantages that can be achieved with the invention are, in particular, that the ink supply of the inking unit meets the requirement for short changeover times, also in view of the fact that the printing inks used are expensive and such an inking unit, which is usually colored with high-viscosity printing inks, is difficult to clean is.

An exemplary embodiment of the invention is shown in the drawings and is described in more detail below.

• 1 eine Vorrichtung zum Bedrucken bzw. zur Dekoration von jeweils eine Mantelfläche aufweisenden Hohlkörpern;
• 2 ein Farbwerk für die in 1 dargestellte Vorrichtung in einer ersten Betriebsstellung;
• 3 das Farbwerk für die in 1 dargestellte Vorrichtung in einer zweiten Betriebsstellung;
• 4 eine perspektivische Darstellung eines zum Farbwerk der 1 und 2 gehörenden Farbreservoirs;
• 5 eine Längsdarstellung des Farbreservoirs der 4;
• 6 eine Querschnittsdarstellung des Farbreservoirs der 4 und 5;
• 7 eine perspektivische Darstellung einer Farbwanne des Farbreservoirs der 4 bis 6 mit einer darin angeordneten Transportschnecke;
• 8 eine Längsschnittdarstellung der in der Farbwanne angeordneten Transportschnecke;
• 9 eine Einzelteildarstellung der Transportschnecke mit einem Rotor einer Farbpumpe und einem Rotor eines antriebsseitigen Kupplungsstücks;
• 10 eine Schnittdarstellung der Farbwanne mit Blick auf eine ihrer Stirnseiten.

Show it:

• 1 a device for printing or decorating hollow bodies each having a lateral surface;
• 2 an inking work for the in 1 Device shown in a first operating position;
• 3 the inking system for the in 1 Device shown in a second operating position;
• 4 a perspective view of one of the inking works 1 and 2 associated color reservoirs;
• 5 a longitudinal view of the paint reservoir 4 ;
• 6 a cross-sectional view of the paint reservoir 4 and 5 ;
• 7 a perspective view of a paint tray of the paint reservoir 4 until 6 with a transport screw arranged therein;
• 8th a longitudinal sectional view of the transport screw arranged in the paint tray;
• 9 an individual part representation of the transport screw with a rotor of a paint pump and a rotor of a drive-side coupling piece;
• 10 a sectional view of the paint tray with a view of one of its front sides.

The printing in particular of the lateral surface of a hollow body with a z. B. multi-colored print motif, ie at least one printed image, is preferably carried out in a letterpress process in which printing ink is first applied to a printing blanket and only from there to the lateral surface of a hollow body. To carry out this special letterpress process, a printing plate is arranged as a printing plate on a lateral surface of a printing form cylinder, which is why this cylinder is sometimes also referred to as a plate cylinder. The printing cliché that is ready for use in the printing process is a printing form with a printing relief, whereby this printing relief reproduces the printed image intended for the printing process of the indirect letterpress process in an unmirrored manner, in contrast to the classic, ie direct letterpress process, whereby in a trouble-free printing operation only the printing relief is on the transfer of the printing forme cylinder printing ink supplied by the inking unit is involved on at least one printing blanket interacting with this printing forme cylinder. The printing form or printing plate to be mounted on a printing form cylinder has a plate-shaped, preferably flexible support of finite length, for. B. made of a steel sheet, with a particularly flexible pressure body being arranged on this carrier. At least the ends of the carrier opposite in the circumferential direction of the printing forme cylinder can z. B. be pre-bent or angled according to the curvature of the lateral surface of the printing form cylinder in order to enable easier assembly of the printing form, ie here in particular the printing plate on the printing form cylinder. The carrier of the printing form or the Printing clichés have a thickness in the range of z. B. 0.2 mm to 0.3 mm. The printing plate, including its carrier, has a total thickness in the range of z. B. 0.7 mm to 1.0 mm, preferably about 0.8 mm. The pressure body is z. B. formed from a plastic. The pressure body is used to produce the printing plate that can be used for the printing process, for example. B. exposed with a negative film that reproduces the printed image, with unexposed areas then being removed from the printing body, for example. B. can be removed by washing or using a laser.

A device for printing or decorating hollow bodies, in particular each having a preferably cylindrical lateral surface, is also referred to as a decorator and preferably has several, e.g. B. eight or ten or even more printing units - also called printing stations -, with at least one of these printing units, in the preferred embodiment all of these printing units, each having a rotatable printing forme cylinder, in particular a printing forme cylinder designed as a plate cylinder, and an inking unit. The printing units or printing stations and possibly also the printing forme cylinders in this device are each stored in a frame and can be used in the same printing process in order to form a multi-colored printing motif on the same hollow body in accordance with the number of printing units or printing forme cylinders involved. As a rule, only a single printing plate is arranged on the lateral surface of each printing form cylinder, with the carrier of the printing plate spanning the circumference of the printing form cylinder in question completely or at least largely, in particular more than 80%. A length of the printing body of the printing plate directed in the circumferential direction of the printing forme cylinder in question is preferably shorter than the circumferential length of the printing forme cylinder in question. The printing form or the printing plate is arranged or at least can be arranged, in particular magnetically, on the lateral surface of each printing form cylinder by means of its carrier, i.e. H. The printing form or the printing plate is preferably magnetic there, i.e. H. held by a magnetic holding force.

In a preferred embodiment, each printing form cylinder has a diameter in the range between 100 mm and 150 mm, in particular between 120 mm and 130 mm, with an axial length of the printing form cylinder in question being z. B. between 200 mm and 250 mm, in particular between 200 mm and 220 mm. The printing plate to be arranged on the lateral surface of the relevant printing forme cylinder has a width in the axial direction of the relevant printing forme cylinder in the range of 150 mm to 200 mm, preferably approximately 175 mm.

Each of the printing form cylinders used in the printing process transfers a specific printing color to a printing blanket with its printing form or printing plate. The printing inks used are usually pre-mixed, especially order-specific special colors, e.g. B. in terms of their respective printability are tailored in a special way to the material of the hollow body to be printed, depending on whether a surface z. B. is printed from aluminum, tinplate or plastic. These order-specific special colors also usually differ in their respective color. In a preferred embodiment of a device for printing or decorating z. B. hollow bodies having a cylindrical lateral surface, a device is provided which transfers printing ink from the printing form or the printing plate to the lateral surface of the hollow body in question. This device that transfers printing ink is preferably designed as a segment wheel rotating about a particularly horizontal axis, with the periphery of this segment wheel, i.e. H. along its circumference, preferably several, e.g. B. eight, ten, twelve or even more printing blankets are arranged or at least can be arranged. The printing blankets are arranged on the circumference of the segment wheel, for example. B. in that the printing blankets on the circumference of the segment wheel are z. B. are attached by a cohesive connection, preferably by gluing. The preferably several printing forme cylinders are each positioned or at least adjustable radially to the printing blankets arranged on the circumference of the segment wheel in question. In a particularly preferred embodiment of a device for printing or decorating one z. B. hollow bodies having a cylindrical lateral surface - d. H. a decorator - a larger number of printing blankets are arranged one behind the other along the circumference of the segment wheel than are provided in each case on the segment wheel radially adjusted or at least adjustable printing forme cylinders.

The preferably carousel-like printing ink transferring device, in particular the segment wheel, has a diameter of z. B. 1,400 mm to 1,600 mm, preferably about 1,520 mm to 1,525 mm, and has at z. B. eight assigned printing forme cylinders on its circumference one behind the other z. B. twelve printing blankets. The surface of each printing plate is preferably designed with a greater hardness than the hardness of the respective surface of the printing blankets. The surface of the printing blankets is preferably flat, ie designed without profiling. In In an operating state in which the printing forme cylinders involved in the printing process are each positioned radially on the printing blankets of the rotary driven segment wheel, the respective printing forms of these printing forme cylinders or the respective printing plates of these printing forme cylinders roll on the printing blankets moved with the segment wheel, the printing plates being at least theirs Press the print relief into the respective printing blanket. An intensity of the impression is e.g. B. before or at the beginning of a printing process e.g. B. can be adjusted or is set in this way by means of a remote control by adjusting a contact pressure exerted by the relevant printing forme cylinder on the relevant printing blanket of the segment wheel.

The printing process for printing in particular the respective lateral surface of z. B. held on a mandrel wheel hollow bodies begins with all the printing colors required for the print image to be printed on the respective lateral surface of the hollow body. B. from the respective printing cliché of z. B. printing forme cylinders placed on the segment wheel can be applied to the same by one of the printing blankets arranged on the circumference of the segment wheel. The printing blanket in question, colored in this way with all the required printing inks, then simultaneously transfers these printing inks in a contact between the printing blanket and the lateral surface of the hollow body to be printed during a single revolution of the hollow body to be printed held on the mandrel wheel about its longitudinal axis onto the lateral surface of this hollow body. During the transfer of the printing inks from the printing blanket to the outer surface of the hollow body, the z. B. hollow bodies to be printed held by the mandrel wheel with a circumferential speed of the same amount as the relevant z. B. printing blanket arranged on the circumference of the segment wheel. The respective circumferential speeds of the hollow body and printing blanket or segment wheel are therefore synchronized with one another, with the z. B. hollow bodies to be printed held on the mandrel wheel, in particular by a drive means z. B. from its standstill, in particular until the peripheral speed is reached, for example. B. the segment wheel is accelerated accordingly. In the preferred embodiment, the segment wheel carrying the printing blanket in question gives the z. B. circumferential speed to be set on the mandrel wheel. The peripheral speed of the printing forme cylinder carrying the printing form or the printing plate is preferably dependent on the peripheral speed, for example. B. the segment wheel is set. 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.

1 shows in a schematic representation, in a simplified and exemplary manner, a device for printing or decorating hollow bodies 01, in particular each having a preferably cylindrical lateral surface, e.g. B. two-part cans, these hollow bodies 01 being fed sequentially with a conveyor device to a transport device designed as a mandrel wheel 02 and held there individually on a holder on this transport device. A device that transfers printing ink, in particular a rotating or at least rotatable segment wheel 03, works together with the mandrel wheel 02, along the circumference of which several printing blankets 13 are arranged one behind the other. In association with the segment wheel 03 mentioned as an example, a plurality of printing forme cylinders 04 are provided along its circumference, which are positioned or at least adjustable to this segment wheel 03, with a printing forme 18, in particular a printing plate 18, being arranged on the respective lateral surface of this printing forme cylinder 04, this printing plate being used in particular for Execution of a high pressure process is designed. Each of the printing form cylinders 04 is supplied with a specific printing ink by means of an inking unit 06 in order to color its printing form or its printing plate. In the 2 and 3 an automated feeding of one printing forme 18 or one printing plate 18 for mounting on the lateral surface of the respective printing forme cylinder 04 is indicated.

2 and 3 show in a simplified schematic representation some details of the inking unit 06, which interacts with a printing forme cylinder 04, which z. B. for use in the in 1 The device shown is provided for printing or decoration, in particular of hollow bodies 01, each of which has a preferably cylindrical lateral surface. The inking unit 06 proposed here advantageously has a very short roller train, ie consisting of only a few, preferably a maximum of five rollers, in particular two-roller rollers, for the ink transport from an ink reservoir to the relevant printing forme cylinder 04. In the case of the two-roller roller train, this roller train only consists of a single inking roller 07 and an anilox roller 08. An inking unit 06 with a roller train consisting of a maximum of five rollers belongs to the type of short inking units.

2 shows an example of an inking unit 06, preferably designed as a short inking unit, with a two-roll roller train in a first operating position in which the inking roller 07 and the anilox roller 08 is placed against one another, the inking roller 07 is placed on the printing forme cylinder 04 and the printing forme cylinder 04 is also placed radially on the device which transfers the printing ink from the printing forme cylinder 04 to the outer surface of the respective hollow body 01, in particular on the segment wheel 03. In the preferred embodiment, in the first operating position of the inking unit 06 cooperating with the printing forme cylinder 04, in which the inking roller 07 and the anilox roller 08 are positioned against one another, the inking roller 07 is engaged against the printing forme cylinder 04 and the printing forme cylinder 04 is also engaged against the segment wheel 03, at least the respective centers of the printing forme cylinder 04, the inking roller 07 and the anilox roller 08 are arranged along the same straight line G. 3 shows, however, for that in the 2 Inking unit 06 shown has a second operating position in which the inking roller 07 and the anilox roller 08 are switched off from each other, the inking roller 07 is switched off from the printing forme cylinder 04 and the printing forme cylinder 04 is also switched off from the device transferring printing ink, in particular from the segment wheel 03.

The printing forme cylinder 04 and the anilox roller 08 are z. B. each independently from a motor 11; 12 rotatably driven, especially in the one preferably used in the 2 and 3 shown inking unit 06, the relevant motor 11; 12 e.g. B. in its respective angular position and / or speed of one z. B. electronic control unit is regulated or at least regulated. The inking roller 07 is or is from the anilox roller 08 z. B. driven rotationally by friction. In the preferred embodiment, an outer diameter d07 of the inking roller 07 and an outer diameter d04 of the printing form cylinder 04 carrying at least one printing form, in particular at least one printing plate, are the same in amount. At least one printing plate is arranged or at least can be arranged on the lateral surface of the printing forme cylinder 04, so that in the embodiment with the same outer diameters d04; d07 the printing form cylinder 04 carrying the printing plate and the inking roller 07 each have an identical circumferential length.

In its preferred embodiment, the inking roller 07 has a closed, preferably rubberized outer surface. The anilox roller 08 has a z. B. coated with a ceramic surface, with a hashur of z. B. 60, 80 or 100 lines per centimeter of axial length of the anilox roller 08 or a cell structure is formed. In order to enable the anilox roller 08 to feed the largest possible amount of printing ink into the roller train of the inking unit 06 with each of its revolutions, an outer diameter d08 of the anilox roller 08 is preferably larger than the outer diameter d07 of the inking roller 07. The anilox roller 08 should therefore have the largest possible delivery volume. In the 2 the respective direction of rotation of the segment wheel 03, the printing forme cylinder 04, the inking roller 07 and the anilox roller 08 is each indicated by a direction of rotation arrow.

The delivery volume of the anilox roller 08 and the viscosity of the printing ink to be transported by the inking unit 06 in turn influence a color density of the printing ink to be applied to the cylindrical lateral surface of the hollow body 01 to be printed. A thickness of an ink film formed by the printing ink to be applied to the cylindrical lateral surface of the hollow body 01 to be printed is z. B. at less than 10 µm, in particular in a range of about 2 µm to 3 µm. When printing hollow bodies 01, in particular when printing cans preferably made of a metallic material, printing inks are used whose respective dynamic viscosity at 25 ° C is usually in the range of 5 Pa s to 30 Pa * s or even higher. These printing inks are therefore rather viscous and therefore not very flowable. These printing inks are considered high-viscosity printing inks.

The ink reservoir of the inking unit 06 is designed as a doctor chamber 09 acting in conjunction with the anilox roller 08. In connection with the doctor chamber 09 there is at least one container 14 for providing printing ink e.g. B. in the form of a paint tray 14 ( 4 until 6 ), at least one squeegee bar 16 that is positioned or at least adjustable axially parallel to the anilox roller 08 ( 6 ) and a pump for conveying the printing ink, ie a so-called ink pump 17 is provided. The ink pump 17 serves the purpose of continuously conveying printing ink provided in the ink tray 14 through the doctor chamber 09 and thereby metering this ink flow. The anilox roller 08 only absorbs a small portion of the amount of printing ink conveyed by the ink pump 17. The vast majority of the amount of printing ink conveyed by the ink pump 17 is conveyed back to the ink tray 14, so that a continuous ink cycle is formed. Printing ink picked up by the anilox roller 08 from the ink reservoir, ie from the doctor chamber 09, transports this anilox roller 08 directly and directly or alternatively via at least one further roller of the roller train belonging to the inking unit 06 to the preferably only one inking roller 07.

Like from the 7 As can be seen, according to the invention the ink cycle in the ink reservoir of the inking unit 06 is carried out by means of an ink tray 14 arranged transport screw 19 is maintained, this transport screw 19 extending in the longitudinal direction of the paint tray 14. During its rotation, the transport screw 19, on the one hand, acts with shearing forces on the printing ink located in the ink tray 14 and thereby overcomes its minimum flow resistance, especially with a non-Newtonian printing ink, and on the other hand, it conveys the printing ink located in the ink tray 14 from a return of the doctor blade chamber 09 to a suction point of the paint pump 17. The return of the doctor chamber 09 and the suction point of the paint pump 17 are on the opposite end faces 21; 22 of the paint tray 14 arranged. The ink pump 17 conveys printing ink from the ink tray 14, for example. B. via a preferably short hose connection 36 to the doctor chamber 09.

The end faces 21; 22 of the paint tray 14 are preferably each formed essentially in a V-shaped profile, with the transport screw 19 being arranged as low as possible at the bottom of the V-profile ( 10 ). The two bottom flanks 41 starting from the base of the V-profile; 42 of the paint tray 14 preferably only have a slight gradient compared to the horizontal H, so that the paint tray 14 has the widest possible opening in relation to its overall height. This design of the paint tray 14 optimizes the arrangement of the transport screw 19 and also makes it easier to clean this paint tray 14, for example. B. with a spatula. It is also advantageous to equip the bottom of the paint tray 14 with feet 38 ( 8th , 10 ), so that this paint tray 14 can be used if necessary, e.g. B. is designed to be self-standing after it has been removed from the inking unit 06. In a very advantageous design of the end faces 21; 22 of the ink tray 14, these each have at least one groove 39, into which corresponding holding elements formed on the doctor blade chamber 09 are placed on the end faces 21 when this doctor blade chamber 09 is removed from the inking unit 06; 22 of the paint tray 14 and so that the doctor chamber 09 can be safely placed on the paint tray 14.

8th shows again the transport screw 19 arranged in the paint tray 14 in a longitudinal sectional view. It can be seen from this that the transport screw 19 is preferably arranged close to the ground in the lower half of the paint tray 14. The paint pump 17 is z. B. designed as an eccentric screw pump executing an eccentric rotational movement ( 9 ). A rotor 23 of z. B. designed as an eccentric screw pump paint pump 17 is connected in a rotationally fixed manner to the transport screw 19 arranged in the paint tray 14. In an advantageous embodiment, the transport screw 19 is arranged in a rotationally fixed manner on a bending rod 24, this bending rod 24 being arranged in a bore of this transport screw 19 which extends along the axis of rotation of the transport screw 19. In this embodiment, a first end of the bending rod 24 is connected in a rotationally fixed manner to the rotor 23 of the paint pump 17 at a first connection point 28, this connection being z. B. is designed as a screw and / or plug connection. The design of a transport screw 19 arranged in a rotationally fixed manner on a bending rod 24 has the advantage that differently shaped transport screws can be easily inserted onto the respective bending rod 24 as required.

The rotor 23 of the paint pump 17 and the transport screw 19 are rotationally driven by a drive 26, which is preferably designed as an electric motor, with a second end of the bending rod 24 z. B. is connected or at least connectable to this drive 26 via a coupling piece 27 ( 4 and 5 ). The second end of the bending rod 24 is at a second connection point 29 by a preferably detachable and z. B. toothed plug connection with a rotor 31 of the coupling piece 27 connected in a rotationally fixed manner. The drive 26 is on the z. B. a flange 33 having stator 32 of the coupling piece 27 mounted or at least mountable.

In particular at the second connection point 29, i.e. H. on the drive side is z. B. a locking bolt 34 for axial positioning of the z. B. with the rotor 31 of the coupling piece 27 rotatably connected transport screw 19 or the bending rod 24 is provided. The rotary drive 26 of the transport screw 19 is thus arranged spatially separated from the rotor 23 of the paint pump 17 because the rotary drive 26 of the transport screw 19 and the rotor 23 of the paint pump 17 are each arranged at the two opposite ends of the bending rod 24. The rotor 23 of the paint pump 17 and/or the rotor 31 of the coupling piece 27 are preferably stored in plastic bearings, e.g. B. each in at least one plastic ball bearing. One advantage of plastic bearings is that they do not require lubrication and/or e.g. B. are detergent resistant. As an alternative to plastic bearings, ceramic bearings or other non-rusting bearings can also be used at this point.

In a particularly advantageous embodiment, the z. B. mechanical first connection point 28 between the rotor 23 of the paint pump 17 and the transport screw 19 or the bending rod 24 and / or the z. B. mechanical second connection point 29 between the rotor 31 of the coupling piece 27 and the transport screw 19 or the bending rod 24 is designed to be detachable without tools, which contributes to a shortening of set-up times.

In summary, this results in an inking unit 06 of a device for printing hollow bodies, having an anilox roller 08 and a doctor chamber 09 which interacts with the anilox roller 08, an ink pump 17 conveying printing ink from an ink tray 14 through the doctor chamber 09 being provided, the ink pump 17 being provided a drive 26 is rotatably driven, with printing ink not picked up by the anilox roller 08 being returned to the ink tray 14. This inking unit is particularly characterized in that a transport screw 19 conveying printing ink from a return of the doctor blade chamber 09 to a suction point of the ink pump 17 is arranged in the ink tray 14, the ink pump 17 being at a first end of the transport screw 19 on a first end face of the ink tray 14 is arranged and wherein the drive 26 which rotationally drives the paint pump 17 is arranged at a second end of the transport screw 19 on a second end face of the paint tray 14. The paint pump 17 is preferably designed as an eccentric screw pump that carries out an eccentric rotational movement. A rotor 23 of the paint pump 17 is connected, in particular in a rotationally fixed manner, to the transport screw 19 arranged in the paint tray 14. In a particularly advantageous embodiment, a bending rod 24, which is connected in a rotationally fixed manner to the transport screw 19, is arranged in a bore extending along the axis of rotation of the transport screw 19, with differently shaped transport screws being able to be plugged onto the bending rod 24 in an interchangeable manner. Furthermore, a coupling piece 27 connecting the transport screw 19 to the drive 26 is preferably arranged at the second end of the transport screw 19 facing the drive 26. The coupling piece 27 preferably has a rotor 31 and a stator 32, with the transport screw 19 or the bending bar 24 connected to the transport screw 19 each being connected in a rotationally fixed manner, in particular by a detachable plug connection, to the rotor 31 of the coupling piece 27. The drive 26 is then arranged on the coupling piece 27, with a shaft 37 of the drive 26 being connected or at least connectable to the rotor 31 of the coupling piece 27. At a connection point 29 facing the drive 26, for. B. a locking bolt 34 is provided for axial positioning of the transport screw 19 or the bending rod 24 which is connected in a rotationally fixed manner to the rotor 31 of the coupling piece 27. To improve the cleaning capability of the paint supply proposed here, the rotor 23 of the paint pump 17 and/or the rotor 31 of the coupling piece 27 are each stored in plastic bearings or in ceramic bearings or in other stainless bearings. In addition, z. B. provided that a connection point 28 between the rotor 23 of the paint pump 17 and either the transport screw 19 or the bending rod 24 and / or the connection point 29 facing the drive 26 between the rotor 31 of the coupling piece 27 and either the transport screw 19 or the bending rod 24 are each designed to be detachable without tools.

Reference symbol list

01

Hollow body

02

Mandrel wheel

03

Segment wheel

04

printing forme cylinder

05

-

06

Inking

07

Ink applicator roller

08

anilox roller

09

Squeegee chamber

10

-

11

engine

12

engine

13

Printing blanket

14

containers for providing printing ink; paint tray

15

-

16

Squeegee bar

17

Paint pump

18

printing form; Print cliché

19

Transport screw

20

-

21

front side

22

front side

23

rotor

24

bending bar

25

-

26

drive

27

Coupling piece

28

connection point

29

connection point

30

-

31

rotor

32

stator

33

flange

34

Detent bolts

35

-

36

Hose connection

37

Wave

38

Stand

39

Nut

40

-

41

ground flank

42

ground flank

d04

outer diameter

d07

outer diameter

d08

outer diameter

G

Straight

H

horizontal

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The 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

• WO 2012/148576 A1 [0002, 0008]
• WO 2011/051072 A1 [0009]
• DE 102019123631 A1 [0010]
• DE 102019123634 A1 [0011]

Claims (10)

Inking unit (06) of a device for printing hollow bodies, comprising an anilox roller (08) and a doctor chamber (09) which interacts with the anilox roller (08), an ink pump (17) conveying printing ink from an ink tray (14) through the doctor chamber (09). ) is provided, the ink pump (17) being rotatably driven by a drive (26), printing ink not picked up by the anilox roller (08) being returned to the ink tray (14), characterized in that a printing ink is in the ink tray (14). a transport screw (19) is arranged which conveys the paint from a return of the doctor chamber (09) to a suction point of the paint pump (17), the paint pump (17) being at a first end of the transport screw (19) on a first end face (21) of the paint tray (14 ) is arranged and wherein the drive (26) which rotationally drives the paint pump (17) is arranged at a second end of the transport screw (19) on a second end face (22) of the paint tray (14). Inking unit (06). Claim 1 , characterized in that the paint pump (17) is designed as an eccentric screw pump carrying out an eccentric rotational movement. Inking unit (06). Claim 1 or 2 , characterized in that a rotor (23) of the paint pump (17) is connected in a rotationally fixed manner to the transport screw (19) arranged in the paint tray (14). Inking unit (06). Claim 1 or 2 or 3 , characterized in that a bending rod (24) which is connected in a rotationally fixed manner to the transport screw (19) is arranged in a bore extending longitudinally to the axis of rotation of the transport screw (19), wherein differently shaped transport screws can be plugged onto the bending rod (24) in an interchangeable manner. Inking unit (06). Claim 1 or 2 or 3 or 4 , characterized in that a coupling piece (27) connecting the transport screw (19) to the drive (26) is arranged at the second end of the transport screw (19) facing the drive (26). Inking unit (06). Claim 5 , characterized in that the coupling piece (27) has a rotor (31) and a stator (32), the transport screw (19) or the bending rod (24) connected to the transport screw (19) each having a detachable plug connection to the rotor (31) of the coupling piece (27) is connected in a rotationally fixed manner. Inking unit (06). Claim 5 or 6 , characterized in that the drive (26) is arranged on the coupling piece (27), a shaft (37) of the drive (26) being connected or at least connectable to the rotor (31) of the coupling piece (27). Inking unit (06). Claim 5 or 6 or 7 , characterized in that a locking bolt (34) is provided at a connection point (29) facing the drive (26) for axial positioning of the transport screw (19) or the bending rod (24) which is non-rotatably connected to the rotor (31) of the coupling piece (27). is. Inking unit (06). Claim 3 or 4 or 5 or 6 or 7 or 8th , characterized in that the rotor (23) of the paint pump (17) and / or the rotor (31) of the coupling piece (27) are each mounted in plastic bearings or in ceramic bearings or in other stainless bearings. Inking unit (06). Claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8th or 9 , characterized in that a connection point (28) between the rotor (23) of the paint pump (17) and the transport screw (19) or the bending rod (24) is designed to be detachable without tools and / or that the connection point facing the drive (26) ( 29) between the rotor (31) of the coupling piece (27) and the transport screw (19) or the bending rod (24) is designed to be detachable without tools.

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