DK3251848T3

DK3251848T3 - DEVICE FOR INDIRECT PRINTING ON CYLINDRICAL PART

Info

Publication number: DK3251848T3
Application number: DK17176477.2T
Authority: DK
Inventors: Wilfried Philipp
Original assignee: Tampoprint Ag
Priority date: 2015-01-27
Filing date: 2015-10-28
Publication date: 2019-02-18
Also published as: DE102015201341A1; EP3251848B1; EP3065950A1; EP3251848A1; ES2704029T3; WO2016119924A1; EP3065950B1

Description

The invention relates to an apparatus for indirect printing on cylindrical parts, comprising an intermediate printing substrate and a means for transferring a printed image to the intermediate printing substrate or for generating a printed image on the intermediate printing substrate.

Cylindrical parts have been printed for centuries using screen printing, the offset method and the flexographic method, and also for some time using the inkjet method. The printed image is usually imprinted on the cylindrical part to be printed by means of a cylindrical roll. The parts to be printed have to be fed to the printing unit and then rotatably held against the outer circumferential surface of the printing cylinder in a complex manner such that the printed image can be transferred to the parts to be printed. The parts then have to be removed. This involves steering movements including accelerations and decelerations which are complex at high process speeds and, in any case, limit the number of printing processes that can be carried out at a time. Furthermore, apparatuses are known in which the intermediate printing substrate is formed by an endless belt which is endlessly guided as a closed belt loop over at least two rollers and receives the printed image on the outer side thereof facing away from each of the rollers, as in US 4,116,126, DE 2435251 Al and DE 199 38 447 Al; these are not for printing cylindrical parts, however. An apparatus having the features of the preamble of claim 1 is known from GB 2512678 Al, but this document does not specify whether the transfer portion of the endless belt extends in a plane or whether the translational feeding of the parts to be printed in the region of the endless belt is carried out in one direction and in one plane.

The problem addressed by the present invention is that of providing an apparatus of the type mentioned at the outset and a method for indirect printing on cylindrical parts, which can be operated or carried out using a design that is less demanding and less complex with regard to feeding, supporting and removing the parts to be printed.

This problem is solved by an apparatus having the features of claim 1. According to the invention, it is proposed that, for the feed means, a positively controlled rotary drive means be provided for the rotatably mounted parts in such a way that an outer circumferential speed of the parts corresponds to a relative speed between the endless belt and the translational feeding of the parts when said parts reach the transfer portion.

According to the invention, an endless belt guided in a closed belt loop is therefore used instead of cylindrical rolls for ultimately transferring the printed image to the part to be printed. This makes it possible for the region in which the printed image is transferred to the particular cylindrical part to be printed to be planar, rather than curved as in the case of a roll. Said planar transfer portion, i.e. a transfer portion extending in a non-curved surface, is formed by the endless belt in a region that is between the rollers of the endless belt in the drive direction. The cylindrical parts to be printed can roll against said planar transfer portion, the printed image being transferred from the endless belt to the particular part to be printed by means of said rolling. Meanwhile, the parts to be printed are fed translationally in said plane and guided along the transfer portion.

In the printing apparatus according to the invention and in the course of carrying out the printing method, the parts to be printed do not need to be brought to a halt in a printing station, pressed against a printing roll and then accelerated again and translationally removed after being printed; instead, this can take place more or less in a single continuous process. Since the parts to be printed are printed by means of rolling relative to the transfer portion that extends in a plane, this can also be carried out in a continuous translational movement of the parts to be printed, as long as said parts are rotatably mounted in the region of the planar transfer portion such that they can roll against the transfer portion. The feed means therefore has a simple design, since it is not necessary to carry out cyclic translational accelerations and decelerations of the parts to be printed and the tool holders thereof. Another advantage of the apparatus according to the invention and the method according to the invention is that transferring a printed image to the intermediate printing substrate or generating a printed image on the intermediate printing substrate is easier because it is possible, again, to transfer or generate the printed image in a planar portion of the endless belt.

It is also proposed for a support means to be provided inside the endless belt by means of which the endless belt can be supported orthogonally with respect to its belt plane in the transfer portion. In this way, it is possible for the endless belt not to be pushed inwards by the rolling movement of the cylindrical parts to be printed, and to therefore maintain the planar extension thereof in a plane. The printed image is therefore not distorted. In the simplest case, said support means can be a sliding block or support block that slides against the endless belt from the inside.

In an even more developed design of this concept of the invention, it is proposed for a positioning means to be provided inside the endless belt by means of which the endless belt can be deflected outwards orthogonally with respect to its belt plane in the transfer portion, i.e. in a direction towards the parts to be printed. This further measure makes it possible to move the transfer portion a little towards a feed plane of the parts to be printed. This movement, deflection or adjustment of the transfer portion can be, for example, in the range of a few millimeters, in particular between 1 and 20 mm with respect to the undeflected course of the endless belt between the two rollers. This makes it possible to specify a position, while the parts to be printed are being fed, at which the cylindrical outer circumference of the parts comes into contact with the endless belt and at which the parts are thus set into rotation. Said rotation is slack-free with respect to the endless belt when the parts to be printed have reached the region of the planar transfer portion at the latest. The parts are rotatably mounted in the feed means for this reason. Meanwhile, said parts are preferably transported translationally at a constant speed.

With regard to different measurements and sizes of the parts to be printed, it is advantageous for the support means or the positioning means to be designed such that the length of the outwardly deflectable portion of the endless belt can be varied in the drive direction of the endless belt. For this reason, the support means or the positioning means advantageously comprises a plurality of optionally adjustable support blocks or sliding blocks that have a different length in the drive direction of the endless belt. It would also be conceivable, however, for rollers, rolls or length-adjustable support elements for the endless belt to be provided inside the closed belt loop of the endless belt. However, it is preferable for a support surface that is continuous, i.e. smooth and joint-free, in the drive direction of the endless belt to be produced on the support means or positioning means.

According to another concept of the invention, it can be advantageous if the positioning means is designed for cyclic operation. This makes it possible for the use capacity, i.e. the number of parts to be printed at a time, to be increased in the case of parts to be printed which have a relatively large diameter, and therefore also have a relatively large peripheral length when rolling but should only be printed with a printed image that is relatively short in the rolling direction. According to the invention, this can be achieved by the positioning means being moved back from a printing position by the part to be printed after a printed image has been transferred to a cylindrical part that rolls against the transfer portion, and then brought back into the printing position towards the next part to be printed. In this way, the parts to be printed can follow one another more closely, i.e. be fed at a higher use capacity, and the printed images can be provided in a comparatively closer succession on the endless belt that acts as an intermediate printing substrate.

As already briefly mentioned above, it is advantageous for the support means or the positioning means to comprise a sliding block against which the endless belt slides. Said sliding block is positioned from the inside, i.e. against the surface of the closed belt loop that faces inwards. Said block preferably comprises a support surface positioned precisely in a plane. However, it can also be advantageous for the sliding block to comprise a plurality of support ridges which extend in the transport direction of the endless belt and of which the ridge surface extends precisely in a support plane. This is advantageous because interlocking coupling elements can be guided between the ridges and act between the endless belt and the at least two rollers. Nevertheless, the sliding behavior in the case that strip-shaped support surfaces of the sliding block are delimited by intermediate spaces is more advantageous.

As already mentioned, it is advantageous that it is not necessary to carry out cyclic translational accelerations and decelerations of the parts to be printed and the tool holders thereof in the feed means. It can, however, also be expedient in some cases for the feed means to have, in addition to translational feeding, an adjusting and resetting movement towards the endless belt or away from the endless belt that superposes said feeding. This also appears to be useful for operational reasons.

It is also proposed for the feed means for the cylindrical parts to be printed to be designed such that it feeds said parts counter to the drive direction of the endless belt in the transfer portion. In this way, a higher relative speed can be achieved between the endless belt and the parts to be printed at the lowest possible inherent speed of the endless belt and the parts to be printed.

According to the invention, as mentioned above, it is proposed that, for the feed means, a positively controlled rotary drive means be provided for the rotatably mounted parts in such a way that an outer circumferential speed of the parts corresponds to a relative speed between the endless belt and the translational feeding of the parts when said parts reach the transfer portion. This is particularly advantageous because the desired outer circumferential speed of the rotating parts can therefore be precisely specified and is not dependent on slack between the rotatably mounted part and the endless belt during the acceleration stage. Higher precision can be achieved in this way. This is particularly advantageous when a plurality of intermediate printing substrates, arranged one behind the other, for transferring and applying a plurality of in particular multicolor printed images are provided instead of a single intermediate printing substrate for transferring one printed image. The problem that arises in this case is that the multicolor printed images have to be applied precisely one on top of the other, i.e. in exactly the same position, on the cylindrical parts to be printed. Precise positively controlled rotary driving of the rotatably mounted parts along the printing distance, i.e. also between the intermediate printing substrates of which there is in particular a plurality, is therefore advantageous and can be readily achieved by means of a positively controlled rotary drive means.

In a development of this concept of the invention, it is proposed for the positively controlled rotary drive means to comprise a rack-and-pinion mechanism. A rack-and-pinion mechanism of this type can comprise a stationary rack which is connected in a rotatably driven manner by means of various pinions to a relevant bearing means in the workpiece supports for each of the parts when or before the parts reach the transfer portion.

As has just been mentioned, it is advantageous for the printing apparatus to be characterized by a plurality of intermediate printing substrates that are arranged one behind the other, and in that the positively controlled rotary drive means extends along the plurality of intermediate printing substrates such that the parts are free of interruptions from the first transfer portion of the first intermediate printing substrate to the last transfer portion of the last intermediate printing substrate, and are rotationally driven, in a synchronized manner, in order to translationally feed the feed apparatus.

It is also advantageous for the means to comprise a gravure printing applicator such that the printed image is transferred to the endless belt by means of gravure printing, i.e. by means of intaglio engraving. It can also be advantageous for the means to comprise a relief printing applicator such that the printed image is transferred to the endless belt by means of relief printing. It can also be advantageous for the means to comprise an inkjet applicator such that the printed image is transferred to the endless belt by means of inkjet application. All the above-mentioned printing techniques and corresponding applicators can be advantageously used in order to form a printed image on the intermediate printing substrate, i.e. the endless belt. When using an inkjet applicator, it is advantageous for said applicator to be arranged such that the printed image is formed in a planar portion of the endless belt.

The endless belt can be produced in different ways. Said belt typically comprises a first supporting planar material. If only a single printed image is generated in the course of a printing process, for example in monochrome printing, it can be sufficient for the endless belt to be guided and driven in a clamped manner, i.e. by means of a friction drive, with respect to the rollers. If a completely slack-free and clearance-free drive is required for the endless belt, for example because a plurality of printed images have to be generated one on top of the other on the parts to be printed during the printing process, e.g. in multicolor printing, it can be advantageous for the endless belt to comprise a first supporting planar material and for the endless belt, in particular the first supporting planar material of the endless belt, to include projections which protrude towards the rollers and interlockingly engage in complementary recesses in the rollers.

It would nevertheless be conceivable for the endless belt to be formed entirely by the first supporting planar material. In contrast, it is also advantageous, however, for the endless belt to comprise a first supporting planar material and for there to be, on the outer side of said belt, an elastically resilient coating of the supporting planar material that is continuous or uninterrupted in the peripheral direction and intended for receiving the printed image.

According to another concept of the invention of particular importance, it is proposed for the elastically resilient coating to be formed by a second planar material that is designed as a preferably endless and closed belt loop and is detachably connectable to the first supporting planar material by being pulled onto the outer side of the first supporting planar material and being brought into a slack-free and clearance-free entraining connection with the first supporting planar material. This makes it possible to replace the second planar material that forms the elastically resilient coating and is subject to wear with another material or a new material, the first supporting planar material being retained or reused.

In a development of this concept of the invention, it is advantageous for the second planar material to be brought into the slack-free entraining connection with the first supporting planar material via means that act in an interlocking manner between the second planar material and the first supporting planar material. A slack-free, high-precision coupling can be achieved by using means that act in an interlocking manner between the planar materials.

In a development of this concept of the invention, it is proposed for the means that act in an interlocking manner to form a rear engagement both in the drive direction of the endless belt as well as perpendicularly thereto.

The means that act in an interlocking manner could be implemented in any desired manner, in particular as additional coupling means. In contrast, it is advantageous for the means that act in an interlocking manner to be formed by projections that are integral with the material of the first or second planar material and complementary recesses in the other planar material.

It is also advantageous for the projections and recesses to be linear or curved in a plan view of the belt plane and, when viewed in a cross section, orthogonal to the belt plane, to be delimited by sides which converge such that they have a continuously tapering design. This embodiment is particularly advantageous because it results in self-centering, in particular in the region of the rollers.

It is also advantageous for the projections and recesses to be arranged in a herringbone pattern with respect to one another in a plan view of the belt plane.

The fact that the endless belt is designed having an elastically resilient coating makes it possible to optimally adjust the physical properties of the particular endless belt that acts as an intermediate printing substrate to the specific printing method, the printing ink and the surface of the parts to be printed. Depending on the application, it is advantageous for the resilient coating to have a Shore A hardness of at least 5, in particular of at least 10, in particular of at least 15 and of at most 80, in particular of at most 70, in particular of at most 60, in particular of at most 50 and more particularly of 30-50.

It is also advantageous for the resilient coating to have a thickness of at least 1 mm, in particular of at least 3 mm, in particular of at least 5 mm and of at most 30 mm, in particular of at most 20 mm, in particular of at most 10 mm.

Depending on the application, the above-mentioned coating of the endless belt is advantageously a silicone-based coating, a polyurethane-based coating, a polyolefin-based coating, a coating based on vulcanized or unvulcanized rubber or a gelatinbased coating. The particular coating of the endless belt is advantageously adapted to the selected printing ink in this case, a distinction typically being made between solvent inks, UV-curable inks and water-based inks.

With regard to mounting the endless belt and adjusting to a desired belt tension, it is advantageous for a tension means for the endless belt to be provided that can in particular be controlled in an open and/or a closed loop. In a development of this concept of the invention, it can be advantageous for the tension means for the endless belt to be operationally coupled to the positioning means for deflecting the endless belt in the transfer portion. In this way, a precise belt tension can be maintained even when the positioning means is operated in a cyclic manner. Distortions of the printed image can thus be prevented.

Furthermore, protection is also claimed for a printing method having the features of each of claims 13 to 15. It should be pointed out that protection is also claimed for all method-related measures that have previously been described in connection with the design of the printing apparatus.

It should also be pointed out that the apparatus according to the invention and the method according to the invention are equally suitable for printing parts that are not formed having lateral faces that are precisely in the shape of a circular cylinder, but instead have a surface or surface portion that is curved such that it can be rolled against a planar surface at least in portions, i.e. can also be rolled against the transfer portion of the endless belt that extends in a plane, and therefore forms a linearly extending geometric contact line or a linearly extending contact strip relative to the endless belt when rolling. Parts of this type have a lateral surface that is only curved with respect to one spatial direction. This therefore includes, for example, circular cylinders or oval cylinders, but not cuboids or bodies having surfaces that are curved with respect to two spatial directions such as spheres or hyperboloids.

Further features, details and advantages of the invention can be found in the enclosed claims, and in the drawings and following description of a preferred embodiment of the apparatus according to the invention. In the drawings:

Fig. 1 is a schematic view of a printing apparatus according to the invention comprising a feed means for parts to be printed;

Fig. 2 is a schematic perspective representation of a sliding block of a positioning means of the apparatus according to claim 1;

Fig. 3 is a schematic view of a printing apparatus according to the invention comprising a plurality of intermediate printing substrates that are arranged one behind the other; and

Fig. 4a)-d) are different views of the first and second planar materials for forming a closed belt loop.

Fig. 1 shows an apparatus, denoted overall by reference sign 2, for indirect printing on cylindrical parts 4. Said cylindrical parts are fed into a printing region of the apparatus and removed therefrom by means of a feed means 6. The apparatus 2 is an apparatus for indirect printing, i.e. a printed image to be transferred to a part 4 to be printed is transferred to an intermediate printing substrate 8 or generated on an intermediate printing substrate 8, and delivered from there to the part to be printed. According to the present invention, said intermediate printing substrate 8 is formed by an endless belt 10 which is endlessly guided as a closed belt loop over, by way of example, two rollers 12. In the case shown by way of example, a means 14, in the form of a plate roller 16 of a gravure or relief printing applicator, for transferring the printed image to the intermediate printing substrate 8 is provided. It would also be possible, however, for an inkjet applicator to be provided as the means for transferring or generating a printed image. In particular an inkjet applicator would then be advantageously arranged so as to come into contact with the intermediate printing substrate 8, i.e. the endless belt 10, between the rollers 12 in an upper planar region 18 of the endless belt 10. This is shown by way of example by indicating the standard colors CMYK of a four-color printing unit above the planar region 18 of the endless belt. In the case shown by way of example, a printed image is transferred from the plate roller 16 to an outer side 20 of the endless belt 10 in the region of the roller 12, and then transported to a transfer station by means of the endless belt 10. A support means 22, designed as positioning means 24 in the present case, is provided inside the endless belt 10, i.e. within the closed belt loop formed by the endless belt 10, in the region of the transfer station. The positioning means 24 comprises a sliding block 26, shown schematically in Fig. 2. The positioning means 24 and the sliding block 26 are arranged in a transfer portion 30 orthogonally with respect to the plane of the endless belt 10 so as to be adjustable. As a result, the endless belt 10 can be deflected in the transfer portion 30 in a direction 28 towards the parts 4 to be printed. The transfer portion 30 can therefore be adjusted back and forth in the direction 28. It is conceivable for this adjustment movement of the sliding block 26 of the positioning means 24 to be carried out once for printing a row of parts 4 of the same type, or for the positioning means 24 to be operated in a cyclic manner, as mentioned in the introduction of the description.

With reference to the schematic representation of the sliding block 26 in Fig. 2, it is possible to see fins or ridges 34 that extend in the drive direction 32 of the endless belt 10 and form an exactly planar surface 36 by means of which surface 36 they slidingly rest, from the inside, on the side of the endless belt 10 that faces inwards. They advantageously comprise a sliding coating, in particular based on a fluoropolymer.

In the case shown by way of example, the feed means 6 comprises an endless, beltconveyor type drive means 38 which is likewise guided as a closed belt loop over rollers 40 and comprises a plurality of workpiece supports 42 for a cylindrical part 4 to be printed in each case. The cylindrical parts 4 are placed on the workpiece supports 42 in a loading station 44, and rotatably retained there. Said parts are successively translationally fed at a constant speed, counter to the drive direction 32 of the endless belt 10, in a direction towards the transfer portion 30 of the printing apparatus 2. In the case shown schematically in Fig. 1, it can be seen that the transfer portion 30 is deflected by means of the positioning means 24 in a direction towards the parts 4 to be printed such that the parts 4 to be printed are in contact with the outer side of the endless belt 10 in the transfer portion 30 and roll against said belt. While the cylindrical parts 4 roll in this way in a slack-free manner against the endless belt 10 as a result of friction, a suitable printed image is transferred from the endless belt 10 to the outer side of the rolling body 4 in the transfer portion 30. When the parts 4 to be printed are first fed to the transfer portion 30 in the direction of the arrow 48, said parts come into contact with the endless belt 10 shortly before reaching the transfer portion 30, owing to the deflection of the endless belt 10 by means of the positioning means 24. As soon as a particular part 4 comes into contact with the endless belt 10, said part is set into rotation virtually immediately and then rolls in a slack-free manner against the outer side 20 of the endless belt 10 that is facing said part. As has already been mentioned, the printed image is transferred from the endless belt 10 to the outer side of the particular part 4.

After a particular part 4 has left the transfer portion 30 and bears the printed image, the printing ink dries until a particular part has been removed from the workpiece support 42 thereof in a removal station 50.

Furthermore, a tension means 52 for the endless belt 10 by means of which the belt tension can be adjusted is schematically indicated. The tension means can be designed so as to be controllable in an open or a closed loop, and in particular to be involved in the operation of the positioning means 24.

The fact that the feed direction 48 of the feed means 6 is counter to the drive direction 32 of the endless belt 10 allows high relative speeds and thus high rates of use to be achieved, the two components being driven at an absolute speed that is lower in comparison.

The fact that a resilient endless belt 10 is used as an intermediate printing substrate 8 allows the printed image to be transferred from a transfer portion 30 that extends in a plane to cylindrical parts 4 that roll against said transfer portion. An arrangement of this type can be compactly constructed since it is not necessary to use large printing cylinders that have large diameters or to carry out major decelerations and accelerations when pressing the parts to be printed, together with the workpiece supports, against cylinder rolls and retracting them from said rolls. Using an endless belt as an intermediate printing substrate and for ultimately transferring the printed image to the parts to be printed allows a plurality of advantageous printing methods and image-generating methods, in particular the inkjet printing technique, to be implemented. It is also conceivable and advantageous for a plurality of the printing apparatuses described above to be operated virtually in a row one behind the other.

This is shown by way of example in Fig. 3, in which two endless belts 10 arranged one behind the other are guided as closed belt loops over two rollers 12 in each case. A means 58 for transferring a printed image in the form of a plate cylinder 16 is also indicated. A printed image is applied by means of the two belt loops as intermediate printing substrates at the same point on the particular cylindrical part 4 to be printed in each case.

In order to ensure that the printed images that are applied virtually one on top of the other by means of the two intermediate printing substrates 8 are applied at exactly the same point on the particular part 4 to be printed in each case, a positively controlled rotary drive means 60 for the rotatably mounted parts 4 is provided for driving the parts on the path thereof from the first intermediate printing substrate 8 to the second intermediate printing substrate 8, or to another intermediate printing substrate, at a precisely specified positively controlled circumferential speed. In the case indicated by way of example, the rotary drive means 60 comprises a rack-and-pinion mechanism 62 that, according to one embodiment, comprises a stationary rack 64 which is connected in a rotatably driven manner by means of various pinions 66 in the workpiece supports 42.

The parts 4 are therefore free of interruptions from the first transfer portion 30 of the first intermediate printing substrate 8 to the final transfer portion 30 of the final intermediate printing substrate 8, and are rotationally driven, in a synchronized manner, in order to translationally feed the feed apparatus. Precise positioning of the printed images can be achieved in this way.

Fig. 4a) to d) are different views of two components that form the endless belt 10. The endless belt 10 comprises a first supporting planar material 70 and an elastically resilient coating 72 in the form of a second planar material 74. The two planar materials 70 and 74 can be designed in the form of an endless closed belt loop by joining strip-shaped portions to one another at the ends thereof. In this state, the second elastically resilient planar material 74, in the closed-belt shape thereof, can be pulled onto an outer side of the first planar material 70, the first and second planar material 70 and 74 being entrainingly connected in a slack-free and clearance-free manner as a result. For this purpose, means 76 that act in an interlocking manner are provided between the first and second planar material 70, 74, more specifically, in the case shown preferably and by way of example, in the form of projections 78 on one material and complementary recesses 80 in the other material. In the case shown by way of example in Fig. 4a) to d), fin-shaped projections 78 are formed on the first supporting planar material 70 that extend in an approximately linear manner, extend in a herringbone pattern (i.e. at an angle to one another and, by way of example, in a linear manner) and are delimited by sides 82 which converge with one another. Recesses 80 that are designed to be complementary to said projections are accordingly formed on the second resilient planar material 74. The planar materials 70 and 74 can thus interlockingly connect to one another in the drive direction 32 and perpendicularly thereto. The shape of the projections 78 that tapers from the belt plane and the complementary design of the recesses 80 allow the two planar materials 70 and 74 to be centered, an unproblematic, mechanically releasable joint between the planar materials that act as endless belts being possible as a result. In this way, when the outer endless belt made of the elastically resilient second planar material 74 becomes worn, it can be unproblematically removed from the first supporting planar material 70 and replaced by a new belt. Projections that protrude towards the rollers 12 and likewise interlockingly engage in complementary recesses in the rollers 12 are preferably provided on the underside (not shown in the drawings) of the first supporting planar material 70 that faces away from the projections 78. Said projections are therefore provided successively in the drive direction 32 so as to be mutually spaced transversely to the drive direction such that, as mentioned above, they can be guided between the fins or ridges 34 of the sliding block 26 (see Fig. 2), for example.

Claims

An apparatus (2) for indirect printing on cylindrical portions (4), comprising at least one print intermediate (8), and comprising a means for transmitting a printed image to the print intermediary (8) or to generate a printed image on the print intermediary (8) ), it is possible for the means to comprise a gravure print applicator, a relief print applicator or an inkjet applicator, the pressure intermediate carrier (8) being an endless belt (10) endlessly guided as a closed belt loop over at least two rollers (12). ) and receives the printed image on the outer side thereof away from each of the rollers (12), the endless belt (10) forming a transfer member (30) extending in a plane between the rollers (12) in the driving direction, and a feeding device (6) is provided for the cylindrical parts (4) to be printed on and the feeding device (6) is designed to translate the parts (4) to be printed on in one direction and in one plane at least in the region of the end hole see belt (10), the parts (4) are rotatably mounted in workpiece carriers (42) of the supply device (6) so that the printed image previously received on the endless belt (10) can be transferred from the endless belt (10) to the cylindrical part (4) to be printed on by rolling the cylindrical part (4) against the flat transmission part (30) of the endless belt (10), characterized in that, for the supply device (6), a forced controlled rotary drive device (60) is provided for rotatable mounting the parts (4) in such a way that an outer circumferential speed of the parts (4) corresponds to a relative speed between the endless belt (10) and the translational supply of the parts (4) when these parts reach the transfer part (30).

Apparatus (2) according to claim 1, characterized in that a positioning means (24) is provided inside the endless belt (10), by means of which positioning means the endless belt (10), in the transfer part (30), can be extended outwards orthogonal to its belt plane in the transfer member (30), where the positioning means (24) is particularly shaped thus at the length of the outwardly deflecting portion of the endless belt (10) can be varied in the direction of travel of the endless belt (10).

Apparatus according to claim 1 or claim 2, characterized in that a support member (22) or the positioning means (24) comprises a sliding shoe (26) against which the endless belt (10) slides.

Apparatus according to one or more of the preceding claims, characterized in that the supply device (6) for the cylindrical parts (4) to be printed is designed to supply these parts against the drive direction (32) of the endless belt (10). in the transfer part (30).

Apparatus according to one or more of the preceding claims, characterized in that the forcibly controlled rotary drive device (60) comprises a racking mechanism (62).

Apparatus according to claim 5, characterized in that the gear exchange mechanism (62) comprises a stationary gear (64) connected in a rotatably driven manner by means of different gears (64) to a relevant bearing member in the workpiece carrier (42) for each of the parts (4) when or before the parts reach the transfer part (30).

Apparatus according to one or more of the preceding claims, characterized by a plurality of pressure intermediate carriers (8) arranged one behind the other and in that the forced controlled rotary drive device (60) extends along the plurality of pressure intermediate carriers (8) so that the parts (4) ) is free from interruptions from the first transfer part (30) of the pressure intermediate (8) to the last transfer part (30) of the last pressure intermediate (8), and is rotatably driven, in a synchronized manner, for translational delivery to the supply device (6).

Apparatus according to one or more of the preceding claims, characterized in that the endless belt (10) comprises a first bearing surface material and in that the endless belt (10), in particular the first bearing surface material of the endless belt, comprises projections which protrudes against the rollers, and formally engages in complementary recesses in the rollers (12).

Apparatus according to one or more of the preceding claims, characterized in that the endless belt (10) comprises a first bearing surface material (70) and in that an elastic resilient coating of the supporting surface material (70), which coating is continuous or interrupted in the peripheral direction, is formed on an outside of the belt to receive the printed image.

Apparatus according to claim 9, characterized in that the resilient resilient coating is formed of a second sheet material (74) which is preferably formed as an endless and closed belt loop and is removably connected to the first supporting sheet material (70) by being drawn on the outer surface of the first supporting sheet material (70) and is provided in a slack-free and veil-free carrier connection with the first supporting sheet material (70).

Apparatus according to claim 10, characterized in that the second surface material (74) is brought into slack-free carrier communication with the first supporting surface material (70) via means (76) which act in a form-closing manner between the second surface material (74) and advantageously, the first bearing surface material (70), the member (76) acting in a form-fitting manner forms a back grip both in the driving direction (32) of the endless belt as well as perpendicular thereto, and is preferably formed by projections (78) integral with the material of the first or second surface material (70, 74) and complementary recesses (80) of the second surface material (70, 74).

Apparatus according to claim 11, characterized in that the projections (78) and recesses (80) are linear or curved in a plane view of the belt plane and, when viewed in cross-section, orthogonal to the belt plane, are limited by sides (82) which converge thus that they have a continuous tapered design.

A method of indirect printing on cylindrical parts (4) using a print intermediate (8), wherein a printed image is transmitted to the print intermediary (8) or generated on the print intermediary (8) via a means for transmitting or generating a printed image, an endless belt (10) which is endlessly passed as a closed belt loop over at least two rollers (12) is used as the pressure intermediate carrier (8), the printed image is received on an outer side (20) of the endless belt (10) facing away from each of the rollers (12), a transfer part (30) is formed which extends in a plane between the rollers (12) in the driving direction and the parts (4) to be printed are successively translationally supplied to the transfer part (30) via a feeding means (6), the parts (4) are rotatably mounted in workpiece carriers (42) of the supply device (6) so that the printed image previously received on the endless belt (10) can be transferred from the endless belt (10) to a cyl Ndisk portion (4) to be printed by rolling the cylindrical portion (4) against the flat transmission portion (30) of the endless belt (10), characterized in that the parts to be printed on are rotatably driven in the feed device (6) by a forced-controlled rotary drive device (60) for rotatably mounted parts (4) in such a way that an outer circumferential speed of the parts corresponds to a relative speed between the endless belt (60) and the translational supply of the parts (4) when these parts reach the transfer part ( 30).

Method according to claim 13, characterized in that, when the printed image is transferred from the transfer part (30) of the endless belt (10), the endless belt (10) is bent outwards orthogonally with respect to the driving direction (32) thereof and the belt plane, in the direction (28) of the part (4) to be printed by a positioning means (24), the positioning means (24) is preferably driven in a cyclic manner for each part to be printed.

Method according to claim 14, characterized in that the endless belt (10) is slidably passed along the positioning means (24).