DE4228128A1 - Printing mechanism for hollow cylindrical bodies - has feed mechanism and rubber-blanket cylinder spaced apart for more than right angle around mandrel wheel - Google Patents

Abstract

Printing is by a rubber-blanket wheel (6) in segments, on an axis parallel to that of the mandrel wheel. The feed mechanism and the blanket wheel are spaced apart around the mandrel wheel periphery for at least 110 deg. The mandrels can be arranged to deflect outwards against the blanket wheel, which can be followed by a painting roller (8), also on an axis parallel to that of the mandrel wheel. The mandrels and the mandrel wheel can rotate in opposite directions. USE/ADVANTAGE - Esp. for cans. Prints bodies all round and at fast rate.

Description

The invention relates to a device and a method for printing of cylindrical hollow bodies, in particular cans, on a rotatable drivable mandrel wheel on rotatable about its longitudinal axis stored almond are attached and the via a feeder Mandrels are fed, the hollow body with an axially parallel rubber blanket segment wheel arranged to the mandrel wheel. Additional Lich can then on the thus printed cylindrical hollow body Apply varnish with clear varnish using a varnishing roller.

It is a device for all-round painting of hollow cylindrical bodies pern, such as B. cans known from DE-A-30 39 812. Likewise are Vorrich lines for printing on cylindrical hollow bodies known, for. B. from the EP-A-0 085 439. These devices have a rotatably mounted, drivable mandrel wheel that rotates axially parallel on its circumference contains stored almond. The hollow body becomes through this mandrel a feed device supplied, the hollow body by means of negative pressure be raised on the mandrels. At a distance of about 100 degrees (Angular degrees) to the feed device is a coating unit or Printing device provided. This consists of an axially parallel to the mandrel wheel arranged rubber blanket segment wheel or a painting roller. This blanket segment wheel is applied by means of applicators such as Inks of the color film as a printed image, possibly also in several Colors, applied. In the area of paint and / or varnish transfer is one so-called mandrel cart control provided for the mandrels, so that the tonsils during the color image or paint contact of the rubber blanket mentrades or the paint roller so that the hollow body in the Roll the color film over the single or double can size.  

The hollow bodies are deflected towards the center of the mandrel wheel. Likewise, a trip mechanism ensures that Mandrels from the color or Paint contact should be stripped off if there is no can on the mandrel.

In order to increase the speed of the printing device, the Diameter of the blanket segment wheel set up so that several Hollow bodies can be printed at the same time.

The hollow body, e.g. B. cans are generally so on the mandrel upset that the can was in the ten-thirty position (if you did that Mandrel wheel as seen on the dial of a watch) in front of the empty one Mandrels transported, then guided parallel to the mandrel and thereby is drawn onto the mandrel by means of negative pressure. This loading process is between the twelve-thirty position and the one-thirty Position closed depending on the speed of rotation of the mandrel wheel. The rubber blanket segment wheel is usually in the three o'clock position positioned. After printing, the can can also be roughly in Five o'clock position to be covered with a clear coat, the paintwork roller rotates counterclockwise.

A disadvantage of the device described above is that at high speeds, some cans are not completely on the Mandrel be raised. This can be caused by defective can geometry be gentle, or it takes place by tilting the can and simultaneously Exposure to negative pressure implodes the thin can wall instead. There the mandrels are already rotating in the production run, usually one will open the mandrel incompletely opened can on the stationary loading pockets torn. Sensors are arranged around the two o'clock position the presence or absence of a can on the mandrel the trip mechanism report, which then ensures that an empty mandrel does not match the Blanket segment wheel comes into contact. Still, ripped open Can bodies that rotate at high speed, the rubber blankets or Damage the coating roller, even when the mandrel is in the removed position Distance of about 4 mm. Even if a damaged can from the sensors is determined, it is very difficult to find this damaged or torn  Can by compressed air in the short time available from that Unload mandrel.

In addition, there is a sensor in the nine o'clock position, the the machine stops when a damaged can is not unloaded could.

To remove a damaged can from the mandrel as well to replace the damaged rubber blanket or the painting roller a machine stop is required. Experience has shown that such a Vorrich device for printing or painting cylindrical hollow bodies several times be stopped for up to 10 minutes every 24 hours.

Since the trip mechanism takes a reaction time, the neighboring ones are Cans for an empty mandrel are not properly printed or varnished. Therefore, 2 to 4 doses must be taken before and after a damaged can be removed. So the damage of a single defective can causes a multiple of rejects. These losses continue to increase the higher the throughput rate and thus the speed of rotation of the bedruk Kungsvorrichtung is.

The object of the present invention is therefore to provide a device for To provide all-round printing of cylindrical hollow bodies, the one higher production speed allowed and by the downtime can be reduced by defective cans.

This object is achieved by means of a device and a Process for printing cylindrical hollow bodies solved. Here the hollow bodies are rotating by means of a feed device Mandrel fed on the circumference of a rotating mandrel wheel to sit. With the mandrel wheel, the hollow body of a device for Printing in the form of an axis parallel to the mandrel wheel Blanket segment wheel supplied. Here are the feeder and Blanket segment wheel arranged on the circumference of the mandrel wheel that you Angular distance is at least 110 °. The angular distance is the  understood the resulting distance on the circumference of the mandrel wheel as the center angle between the connecting line center point of the Mandrel wheel / the can feed and the line center of the Mandrelra of the blanket segment wheel results. Furthermore, the direction of rotation is Mandrel to Mandrelrad in opposite directions and the direction of rotation of the rubber blanket mentrads in the same direction as the mandrel wheel, so that there is a parallel movement supply device between the cylindrical hollow body and the blanket segment rad at the point of contact.

It is preferred if the angular distance is 140 to 300 degrees. An arrangement is particularly preferred so that the feed device and the printing roller is arranged at a distance of approximately 180 degrees.

The preferred arrangement according to the invention of the feed device in eleven Clock position and the rubber blanket segment wheel in five o'clock position has to Consequence that an extended, z. B. doubles pelte, loading and test track to identify and eliminate defective Cans is available. Due to the extended distance between loading the cans on mandrel and contact with the blanket segment It is still possible to open the cans towards the mandrel slow down so that a lower vacuum is used can. This has the advantage that the cans are gentler on the mandrels be raised, so that overall fewer cans when mounting on the Mandrels, e.g. B. be damaged by implosion. The extended one Test section for the detection and elimination of damaged cans allowed it, cans recognized as defective if necessary by compressed air or other Remove aids from the tonsils.

Furthermore, the direction of rotation when working according to the invention Mandrel and blanket segment wheel changed. While working after the State of the art the direction of rotation of the mandrel in the same direction as the The direction of rotation of the mandrel wheel is, i.e. the peripheral speed the can is the sum of the individual circumferential speeds, and the blanket segment wheel in an axially parallel position an opposite Direction of rotation to the mandrel, so that the hollow body to be decorated  should have a parallel direction of movement in the case of the invention The direction of rotation from Mandrel to Mandrelrad work in opposite directions and likewise the direction of rotation of the blanket segment wheel in opposite directions on the direction of rotation of the mandrel. So that the peripheral speed the hollow body to be printed and the blanket segment wheel redu graces. Due to the slower peripheral speed, the speed is lower Color mist guaranteed.

When working according to the state of the art, it is necessary to have a to obtain the highest possible throughput rate of the device that several e.g. B. three, roll cans simultaneously on the blanket segment wheel or be printed. This requires a large diameter of the rubber blanket mentrades. Furthermore, it is necessary to take several doses at the same time To be able to bring contact with the rubber blanket segment wheel that the mandrel on its circular path on the mandrel wheel according to the circumference of the Blanket segment wheel are deflected. When working according to the invention is at the same peripheral speed of the mandrel wheel, that is at same throughput, a slower peripheral speed of the rubber blanket segment wheel and the color flow possible. This makes it an execution Form possible that only one can is printed at a time. This can the dimension of the printing wheel can be reduced and it is a Simplification of auxiliary units such as paint chairs possible without the through to reduce the rate of the device.

Another object of the present invention is in the changes The mandrel control mechanism for printing. While at State of the art it is necessary to print simultaneously from several cans to allow this to the circular path on the circumference of the Leave Mandrelrades, and at the printing device on one Circular path in the scope of the blanket segment wheel is deflected, it is possible when working according to the invention, only a single can print. This makes it possible for this single can not to inside (to the center of the Mandrel wheel) from the circular path of the Mandrelra which is steered away. According to the invention, it is also possible that Mandrel on the mandrel wheel through a mechanism to the outside  Paint roller too, is deflected. The advantage of the invention The procedure is that when the mandrel is deflected outwards the existing through the high peripheral speed of the mandrel wheel Forces (centrifugal force) can be used. For this reason, the necessary mechanical device for this process easier and be made easier. Furthermore, the method according to the invention offers Ren the deflection of the mandrel the advantage that with an empty mandrel no longer have to blow off the 2 to 4 doses before and after this.

The usual printing and additional devices are on the blanket segment wheel arranged. These are used, for example, to apply the printing ink on the surface of the plate cylinder and from there on the rubber blanket. There are also several parallel devices for several colors possible. The usual control devices are also present.

The device according to the invention can also be a device for Include application of a varnish on the printed can. Because of the cheap small dimensions with which the printing device according to the invention device can be formed, it is possible between the printing process direction and the device for removing the finished printed cans from to use a painting device on the mandrel wheel. This consists of at least one axially parallel to the mandrel wheel and the printing device device arranged painting roller, onto which by means of suitable applicators te, e.g. B. an application roller, the coating agent in the necessary Layer thickness is applied. From this painting roller the over traction agent applied to the hollow body to be painted. An advantage The design of the metering roller is a rotogravure cylinder with or without squeegee. Such rotogravure cylinders are, for example, a steel or ceramic roller with cup-shaped depressions that absorb the paint can, excess paint is wiped off with a squeegee or by a second roller is squeezed.

According to the invention, the size of the coating roller should be small. It is Particularly advantageous if the diameter is less than 600 mm. In in this case it is namely possible between the blanket segment wheel and the  Unloading the cans from the mandrels to the coating device on the Position mandrel wheel. It is particularly advantageous if the Painting roller and the metering device combined in a cassette are. In this case, it is possible in the event of malfunctions, with Abnut or if the coating agent is changed, the standstill times of the printing and coating device as short as possible hold. This is possible because the coating unit with application roller and metering roller as well as the parts that come into contact with paint in one Stuck can be removed from the machine. Necessary cleaning and maintenance work can then be carried out regardless of the printing and painting device are carried out. In this one more existing new cassette installed in a shorter time than the Work according to the state of the art.

Particularly suitable devices for a device according to the invention Varnishing cassettes are in the older German patent application P 42 06 938 described by the same applicant.

The device according to the invention will be described with reference to a schematic drawing ( Fig. 1) and a preferred embodiment. The drawings represent a schematic sectional view of the device for printing on cylindrical hollow bodies.

In the drawing, part of the mandrel wheel ( 1 ) is shown schematically. The cylindrical hollow body ( 3 ) to be printed is inserted into this at the ten o'clock position. These move on a circular path ( 2 ) on the mandrel wheel. They are pulled onto the mandrels in stationary loading pockets ( 4 ). The mandrel wheel ( 1 ) can be driven about its central axis in the rotation of the arrow (a) and is equipped on its circumference with mandrels ( 5 ) which are distributed at a uniform distance on the circumference of the mandrel wheel. The mandrels are rotatably mounted and have a direction of rotation (b) opposite to the direction of rotation of the mandrel wheel. The hollow bodies ( 3 ) to be printed or painted are fed onto the mandrels and, in the example, are drawn onto the mandrels ( 5 ) with negative pressure from about eleven o'clock position. This process is completed depending on the throughput speed up to the one-thirty position.

The device for printing cans, a rubber blanket segment wheel ( 6 ), is approximately in the five o'clock position. The direction of rotation (c) is opposite to the direction of rotation of the mandrel wheel. On the circumference of the rubber blanket wheel ( 6 ) there are one or more application devices ( 7 ) for up to six different printing inks.

In the embodiment of the device according to the invention shown in FIG. 1, a painting roller ( 8 ) with application device for paint connects to the rubber segment wheel ( 6 ). A clear varnish can then be applied to the printed cans. The number ( 9 ) denotes the device for removing the painted cans from the mandrels and for continuing the painted cans, for example to a drying device, such as a drying oven.

Along the circumference ( 2 ) of the mandrel wheel, between the one o'clock thirty position and the five o'clock position, sensors are arranged according to the invention which detect the presence and absence of cans on the mandrel and the presence of defective cans on the Find Mandrels. A sufficiently long distance is available for the test process by the sensors. Furthermore, devices for removing defective cans can be located on the sensors before they are fed to the printing or coating device. It can be, for example, a trip mechanism that strips away defective cans before printing or painting.

The device according to the invention also contains control mechanisms, not shown in the drawing, in order to deflect the mandrel according to a mandrel control curve to adapt to the circular path or the radius of the rubber cloth segment ( 6 ), which has an opposite direction of rotation to the mandrel wheel. The mandrels are displaced transversely to their longitudinal axis in the direction of the center of the mandrel wheel ( 1 ), so that the mandrels are deflected from the circular path ( 2 ) of their central axes onto a circular path along the rubber segment wheel ( 6 ). It is necessary that a certain contact pressure on the blanket segment rad or the painting roller is provided so that printing ink or varnish is transferred to the can.

Another advantageous embodiment of the invention ( FIG. 2) contains, on the mandrel wheel, a device (not shown) for a mandrel control curve, in which the mandrels are deflected outwards. The cans to be printed are individually deflected outwards and pressed against the rubber blanket segment wheel. Since only one can runs on the rubber blanket segment wheel ( 6 ) with application devices ( 7 ), this can have a smaller diameter.

A varnishing device ( 8 ) can be provided at a distance after the rubber blanket segment wheel ( 6 ). This consists of a painting roller arranged axially parallel and an associated application device, preferably a rotogravure roller, with or without a doctor blade. A particularly suitable embodiment is the painting device in the form of a closed and easily replaceable cassette. The cans are deflected to the coating roller using the same method as described for the rubber blanket segment wheel. It is therefore possible that the cans on the mandrels are deflected inwards towards the center of the mandrel wheel and roll on the painting roller ( FIG. 1), or they are deflected outwards ( FIG. 2) and then take on the painting roller the paint application. After the painting device, a known removal device ( 9 ) is provided for the cans from the mandrels. Devices for this are known. The printed and possibly overpainted cans are further known process steps, eg. B. drying ovens supplied.

The device according to the invention makes it possible to increase the throughput increase the speed of the device. There are longer distances to Checking and removing damaged cans are available so that Still downtimes avoided due to damage to the printing device become. Furthermore, it is possible through the changed arrangement and Direction of rotation of the printing device a printing with less To allow rejects and paint mist. The dimensions of the  Printing device can be downsized. Due to the reduced Dimensions of the printing and coating device is a simpler Repair and maintenance possible.

Claims (14)

1. Device for printing on cylindrical hollow bodies ( 3 ), with a rotatably mounted, drivable mandrel wheel ( 1 ), with a mandrel ( 5 ) rotatably mounted about its longitudinal axis, with a feed device which feeds the hollow bodies to the mandrel, with a device for printing in the form of a rubber blanket segment wheel ( 6 ) arranged axially parallel to the mandrel wheel, characterized in that the feed device and the rubber blanket segment wheel ( 6 ) are arranged on the circumference of the mandrel wheel ( 1 ) in such a way that their angular distance is at least 110 degrees. 2. Device according to claim 1, characterized in that the angle distance is 140-300 degrees. 3. Device according to claim 1, characterized in that the angle distance is up to 180 degrees and preferably 180 degrees. 4. Device according to one of claims 1 to 3, characterized in that the mandrels are designed to be deflectable to the outside of the rubber segment wheel ( 6 ). 5. Device according to one of claims 1 to 3, characterized in that the mandrels ( 5 ) on the inside of the blanket segment wheel ( 6 ) are designed to be deflectable. 6. Device according to one of the preceding claims, characterized in that after the blanket segment wheel ( 6 ) a painting roller ( 8 ) is arranged axially parallel to the mandrel wheel ( 1 ). 7. Device according to one of claims 1 to 6, characterized in that the direction of rotation (b) of the mandrel ( 5 ) is opposite to the direction of rotation (a) of the mandrel wheel ( 1 ). 8. Device according to one of claims 1 to 7, characterized in that the direction of rotation (c) of the rubber blanket segment wheel ( 6 ) is parallel to the direction of rotation (a) of the almond wheel ( 1 ). 9. The device according to claim 6, characterized in that the Lak kierwalze ( 8 ) is present in a cassette. 10. Device according to one of the preceding claims, characterized in that between the feed device for the cylindri's hollow body ( 3 ) to the mandrel ( 5 ) and the rubber blanket segment wheel ( 6 ) devices for detecting improperly loaded mandrel and defective cans and, if necessary, facilities for removing defective cans. 11. A method for printing on cylindrical hollow bodies, in which the cylindrical hollow body on the tonsils of a rotating mandrel Rades are raised on a device for recognizing not properly loaded almond and defective cans be guided and then a device for printing in the form be fed a blanket segment wheel, characterized net that one with a distance between the feeder and the device for printing at least 110 angular degrees is working. 12. The method according to claim 11, characterized in that according to the Detect defective cans in front of the device for printing be removed from the mandrels. 13. The method according to claim 11 or 12, characterized in that one works with a direction of rotation of the mandrel that is opposite to the direction of rotation of the mandrel wheel.   14. The method according to any one of claims 11 to 13, characterized in net that the printed cans on the mandrels by means of a lac can be painted and after removal of the mandrel one Oven drying can be supplied.