DE102018125960A1 - Method and device for inspecting containers - Google Patents

Abstract

Method for printing objects and in particular containers (10), the containers (10) being transported along a predetermined transport path (P) and at least temporarily being printed on their outer surface by means of at least one printing unit (4, 6, 7), the printed ones Containers (10) are inspected by an inspection device (8), the printing units (4, 6, 7) receiving modified printing commands at least temporarily in a test mode and containers (10) being printed at least temporarily by these modified printing commands in such a way that at least one distinguishes the containers printed in the test mode from the containers (10) printed in a production mode in at least one feature of the printed image, and the containers (10) printed in the test mode are subsequently inspected by the inspection device (8).

Description

The present invention relates to an apparatus and a method for printing on containers. Devices and methods for labeling containers have long been known from the prior art. In recent times, however, it has started to provide containers with direct printing or with multi-color printing. Devices and methods of this type for printing on containers are also known from the prior art. The direct printing of containers is particularly advantageous when small batches are to be produced, since the printed images can be changed quickly.

However, this raises the question of how the print image can be inspected. According to the prior art, a print image control monitors the print for possible errors, such as. B. register errors, nozzle failure, colorimetric deviation, which are mentioned here as examples. The control is preferably carried out using a line or matrix camera. The print image is scanned and checked for errors. A so-called master print, a template from prepress or an image calculated backwards from the RIP files of the printing unit serves as a template. The masterprint is a reference image of one or more good samples. If the inline control system is set to the print image, in the state of the art one or more samples must still occasionally be taken from production and subsequently checked manually to ensure adequate quality control. Without this manual control, it cannot be ensured in the prior art that the automatic print image control works satisfactorily.

The following inspection system is known from the filling area of reusable containers: The performance and functionality of an inspection system in inline operation can be checked cyclically. The systematic implementation takes place as part of a test container program. The test container program in the empty bottle inspector, also called EBI (Empty Bottle Inspection), is standardized and relevant for liability-relevant processes. Here, at certain time intervals or after a certain number of containers produced, one or more containers identified as test containers and provided with certain errors (types) are set during production. The containers identified as test containers are automatically or manually removed from the production flow after the machine. During the test container program run, the inspection results of the test containers are collected in the machine and compared with the specifications of the program. In the best case, all requirements are met. If not, the program can either be repeated or the cause remedied. The execution of the test container program is recorded in each case and serves as proof of the perfect functioning of the inspection in the empty bottle inspection machine. If a type change is made to another container or the machine is restarted, the test container program is carried out before the start of production or after changing to a new type. The functionality is (again) checked and documented. The identification of the test containers can contain a coding that is included in the comparison of the results obtained. So z. B. the test container A has one or more faults or error categories, the test container B in turn others. In this way, only the error results of the control stations that are applied to container A can be taken into account.

• Nachteilig wäre zum einen, dass beim Einstellen von vorgefertigten Testbehältern der Druckprozess für diesen Behälter unterbrochen werden muss. Andernfalls würde der Testbehälter mit dem aktuellen Design überdruckt werden.

According to the current state of the art, it is disadvantageous that there is currently no inline test program during production in a printing press for containers. If a test container program were set up in analogy to the EBI, there would be further disadvantages:

• On the one hand, it would be disadvantageous that the setting process for prefabricated test containers would have to interrupt the printing process for this container. Otherwise the test container would be overprinted with the current design.

It would also be disadvantageous that a print image change in the direct printing process is usually carried out several times per hour. This possibility of frequent changes is an advantage in the direct printing process. This change of print image would correspond to a change of type in the EBI. With the EBI, a new test run is required each time a variety is changed. If test containers had to be set up again each time the printed image was changed in the direct printing process, this would have a major impact on the efficiency of the system.

The variety of necessary test containers would also be disadvantageous if they had to be adapted to the respective printed image. This variety of test containers could be abolished by neutral and standardized test containers. A disadvantage of standardized test containers are, for. B. anonymized errors (types). These errors would be checked and recognized in the control unit. An anonymized error can be a registration mark, a color palette, a standardized text, etc. In addition to checking the actual print image, the control unit would also have to contain specialized controls for the anonymized errors. However, because these do not directly relate to the current print image, it would be possible that the actual print image control is so insensitive that it hardly makes a real mistake recognizes that the special controls for anonymized errors, on the other hand, could be very sensitive. As a result, practically no or hardly any faults would be recognized in real production, while all faults were recognized during the test container run. There is therefore a risk of a large discrepancy between the production and the test.

The invention is therefore based on the object of providing a method and a device which enable sufficiently good control without having the disadvantages mentioned.

In a method according to the invention for printing objects and in particular containers, the containers are transported along a predetermined transport path and at least temporarily printed on their outer surface by means of at least one printing unit. The printed containers are inspected by an inspection device.

According to the invention, the printing units in a test mode receive at least temporarily modified printing commands and containers are at least temporarily printed by these modified printing commands in such a way that at least one of the containers printed in the test mode differs from the containers printed in a production mode in at least one characteristic of the actual print image. According to the invention, the containers printed in the test mode are inspected by the inspection device.

The “actual print image” is to be understood in particular as the elements of the print image that are also printed in principle in a production mode. In particular, the term "actual print image" does not include additional elements such as codes, etc., which are not printed on containers in a production mode. The "actual print image" is therefore particularly free of test codes.

The printing units can thus advantageously be operated either in a production mode or in a test mode. In the so-called production mode, containers are printed which are to remain in production, i.e. it is normal operation. In the test mode, however, the containers are deliberately printed in such a way that they differ from the containers printed in the production mode in at least one characteristic of the printed image. In the test mode, test containers with their test properties are thus advantageously produced in the printing press.

The modified print commands preferably generate a print image that corresponds to the print image as it is generated due to typically occurring errors in printing processes. "Errors" are therefore deliberately built into the print image on the test containers. These typically occurring errors can be, for example, missing color, a nozzle failure, register errors, a disturbed, missing or incorrectly continuous printing, deviations from the printed image, mistake, smear, spray, etc.

The print image can contain one or more types of errors. It is advantageously a type of error which is selected from a group of types of error which contains missing color, nozzle failure, register errors, disturbed, missing or incorrectly continuous printing, deviations from the printed image, mistake, smear, spray.

These selected errors are preferably used to simulate what a corresponding print image would look like if this or these errors occurred. It is therefore advantageously also possible to simulate several types of error per container. The types and sizes of faults are preferably known and a print image is simulated from this information. This simulated print image is advantageously applied to a test container using at least one printing unit.

This simulation can advantageously be designed as a function of the printing press, the print head and / or the print control. However, it would also be conceivable to realize the “faulty” print image in advance when creating it or print files (RIPs) as an independent print image. In any case, however, there is advantageously no predictive management of test containers that have been printed in advance and that have to be inserted into the production stream in good time. The printing machine advantageously has modified print commands / print sequences and / or generates them in order to generate special errors in the test container in the current print job.

In a preferred method, containers with a printed image are generated without the typically occurring errors in the test mode. “Without errors” can mean, in particular, that the print image corresponds to the image as it should be printed in production mode. It is not excluded, however, that an additional marking is applied in addition to the printed image, as in the production mode.

These containers can advantageously serve as a reference. It can thus be advantageously checked whether the inspection device behaves in the same way in the case of test containers as without Test containers, i.e. with production containers. It can thus be excluded, for example, that the inspection device erroneously ejects all test containers. By supplying “incorrectly” printed and “correctly” printed test containers to the inspection device, it can be verified particularly easily whether the inspection device also identifies the incorrectly printed containers in the production plant, but does not object to the correctly printed containers.

In a further preferred method, the inspection device inspects the printed containers in a test mode in the same way as in a production mode. The test containers are therefore advantageously inspected like any other container. The advantage here is that the inspection in test mode goes through the same routines as in production mode. This ensures that no separate control routine is run in the test mode and that the sensitivity does not deviate from the production mode. The test run therefore preferably monitors the result of the check. In the orderly sequence, the intentionally incorrectly printed container should be recognized by the recognition.

In a preferred method, the test containers are created directly from the containers produced.

However, it is advantageously possible that the inspection runs through different test tasks depending on the batch. This is particularly advantageous because test specifications can be individually adapted to the batch. It may be that a color deviation is very important to the client in one batch, but this is not necessary in the next batch, because the basic color is printed in one color. It is also possible that an OCR should be carried out in another batch, but no text was printed in the previous batch.

In a preferred method, the containers printed in a test mode are provided with a code which identifies them as test containers. On the one hand, it would be possible for an external coding to be applied before the test containers are inserted into the printing press. However, it is also possible for the test containers to be coded as test containers only by the printing press. In particular, it is possible for the coding to be applied by the printing units together with the actual print image. If the actual printed image corresponds to the printed image, as it should also be applied in production mode, the container is referred to in the present case as a “without error” container.

It is therefore necessary to differentiate between containers in production mode and containers in test mode (so-called test containers) with coding. In both cases, defective containers can occur - in production mode unintentionally and without coding, in test mode intentionally and with additional coding. Containers in which the actual printed image corresponds to the target specifications are to be regarded as containers “without errors”. Only this actual print image is applied in production mode, and the actual print image is applied with an additional coding in test mode.

Advantageously, the at least one feature by which a container printed in the test mode differs from the containers printed in a production mode does not differ from the additionally applied coding. Instead, this feature is advantageously based on the simulated error.

It is preferably an easily readable coding. The coding is advantageously legible for a person, such as an operator. This coding can be, for example, the printing of a term such as “sample” or “test pattern” or another special symbol in order to be easily identified by an operator.

The coding is particularly preferably legible for a machine. It is conceivable that the coding is easy to read either only for the machine or for one person and one machine. This coding is advantageously a suitable feature that can be easily identified by sensors or systems, such as, for. B. a banderole with a machine-readable 1D or 2D code, or a color dot or ring. This coding is advantageous by suitable sensors, such as. B. a code reader or color sensor, can be identified with an additional test pattern container detection.

In a further preferred method, in addition to the coding, data can be printed which identify the container, in particular for later logging. In this case, for example, data could be printed on, such as a date, a time, a description of the container, a manufacturer, data which characterize the printing unit and the like.

If the containers already have a test code before they are introduced into the printing press, the printing press is prompted for a test run in an advantageous method when the test containers are inserted into them, that is to say put into test mode. In the alternative advantageous method, in which the coding in the machine is applied, the test mode is called by a test container program call.

In an advantageous method, the containers coded as test containers are sorted out regardless of the result of the inspection device after the inspection. The test containers are therefore advantageously removed from the production stream downstream of the check because of their coding. This can be done automatically or manually. The test containers are thus advantageously separated from the actual production. It is also possible that the sorting only after a post-treatment unit, for. B. an independent curing unit. The test containers can preferably be rejected in the same way as the printing errors are rejected. The containers do not have to be reused.

In a further advantageous method, the objects, in particular containers, are transported individually. The containers thus preferably have a predetermined division between them. The containers are advantageously guided along an at least sectionally circular transport path. For example, containers can be fed to a printing unit and transported with these individual printing units and, in a printed state, can be returned to a discharge device.

In particular, as mentioned above, the objects are containers and particularly preferably plastic containers and particularly preferably plastic bottles. However, it would also be conceivable to apply the invention to other containers, for example glass containers and metal containers (for example made of tinplate or aluminum).

The applied print is advantageously a multi-color print.

Preferably, at least two printing units apply prints to at least partially identical areas of the container. These printing units can, for example, apply different color components. However, it would also be possible for the printing assemblies to apply complementary prints approximately along a longitudinal direction of the container, an overlap region of the container which is printed by both printing assemblies preferably being provided.

In a further preferred method, the inspection device records at least one image of the container to be inspected. It is also possible for the inspection device to take several images of a print. In addition, it is also possible that the inspection device scans or scans the containers (in particular optically and contactlessly) and, for example, moves the container relative to the inspection device during this scanning, e.g. B. is rotated and or the inspection device is moved during this scanning in a longitudinal direction of the container.

The inspection device advantageously compares the printed containers with a stored reference image. These reference images are preferably master prints, templates from prepress and / or images calculated backwards from the RIP files of the printing unit.

In a further preferred method, the objects are examined, in particular inspected, during a standstill. This means that the containers are first printed and then preferably stopped in the area of the inspection device and can thus be examined.

In a further preferred method, the inspection device evaluates at least one color property. A color management system (CMS) is preferably used for evaluating the inspection result in order to bring the color spaces of an image recording device, such as a camera (this is an additive color space) and the CMYK printing system (subtractive color space) into corresponding harmony.

Methods can be used which use matrix profiles and / or LUT profiles. LUT profiles are preferred. In a color management or color management system, a LUT (Look Up Table) can use completely different types of color profiles, such as the color space of the camera and that of the CMYK printing system. The matrix profiles mentioned above are simpler, smaller and are often used for monitors. In the case of a matrix ICC profile, the input RGB values are transformed into profile connection space values by means of a mathematical operation (a 3x3 matrix). In the case of a LUT profile, tables are required which contain entries for each combination of an entered RGB value and a corresponding CIELAB value.

The inspection device preferably differentiates between different types of defects in the printed image when inspecting printed containers. The inspection device particularly preferably distinguishes which of the typically occurring types of error are concerned. In particular, the inspection device differentiates between Types of errors such as missing color, a nozzle failure, register errors, a disturbed, missing or incorrectly continuous printing, deviations from the printed image, mistake, smear, spray, etc. A preferred method can therefore also check whether and depending on and with a suitable test coding the inspection device has recognized the corresponding type of error.

The test run can advantageously be logged and documented. The documentation can preferably be done as a simple NOK or OK. Documentation with a detailed error size is also advantageous.

In a preferred method, the error size, e.g. B. how large a register error may be, adjustable from print job to print job without much additional effort. So z. For example, for the brand label "A" the size of the error can be chosen smaller than for the brand label "B". The "errors" in test mode are therefore advantageously printed more narrowly or further. The error limit of the control is preferably set to the specification of the print job.

Particularly advantageously, the test container run can be fully automated without any special effort. Operator intervention to inject test containers into the production stream is eliminated. Instead of the operator intervention, there is advantageously an automatic test container feed when, for. B. neutral containers with test coding should be introduced. This also does not apply if no test container coding is required because it is generated in the printing press itself.

A further advantage of the present invention is that the careful storage of test containers, especially with regard to soiling, against bleaching, against fingerprints, etc., is eliminated.

The present invention is further directed to a device for printing objects and in particular containers. This device has a transport device which transports the containers along a predetermined transport path, at least one first pressure unit, which is suitable and designed to apply pressure to an outer wall of the container, and at least one inspection device.

According to the invention, the containers in a test mode can be printed at least temporarily by modified print commands such that at least one of the containers printed in the test mode differs from the containers printed in a production mode in at least one feature in the printed image, and according to the invention the containers printed in the test mode are from the inspection device inspectable.

The device described is in particular set up and intended to carry out the method described above, i.e. that all features carried out for the method described above are also disclosed for the device described here and vice versa.

In a preferred embodiment, the device also has a control device. The control device advantageously controls the printing of the containers by the at least one printing unit.

In a further preferred embodiment, the inspection device has a color camera or generally an image recording device which is suitable for recording spatially resolved images. The camera is advantageously a matrix or line camera.

In a further advantageous embodiment, the device has an illumination device which illuminates the containers, in particular during their inspection. In this way, uniform lighting of the containers can be achieved.

The inspection device can be part of the printing press and the printing press can optionally include an independent device for separating the test containers so that the test containers can be automatically rejected after the inspection.

An advantageous embodiment also has a rotary star on which the containers are transported.

The at least one printing unit is preferably arranged in a stationary manner (based on the transport path of the containers) and the containers are guided past this printing unit. However, it would also be conceivable that the printing unit with the container is moved along the transport path.

The device advantageously has at least two printing units. A separate control device is preferably assigned to each printing unit.

The pressure units can be pressure units in the narrower sense. In the context of the invention, however, printing units are also understood to mean units such as film modules, which are used to implement metallic effects. This could be, for example cold foil stamping (or inline foiling). Such assemblies could at least partially replace the printing assemblies described above. In addition, it would also be conceivable for the printing unit to print the glue. The test methods described here can also be used here.

Further advantages and embodiments result from the attached drawings:

• 1 eine schematische Darstellung einer erfindungsgemäßen Vorrichtung;
• 2 eine Darstellung einer erfindungsgemäßen Vorrichtung, insbesondere der Druckmaschine;
• 3 RIP-Dateien bzw. die zugehörigen Masterprints von aufeinanderfolgenden Druck-Aufträgen;
• 4 RIP-Dateien mit exemplarisch definierten Druckfehlern;
• 5 eine Ausgestaltungsform der erfindungsgemäßen Vorrichtung, bei der die Codierung in der Druckmaschine aufgebracht wird;
• 6 eine Ausgestaltungsform der erfindungsgemäßen Vorrichtung, bei der Behältnisse mit Codierung in die Druckmaschine eingebracht werden;
• 7 eine Ausgestaltungsform der erfindungsgemäßen Vorrichtung, bei der die Inspektionseinrichtung in die Druckmaschine integriert ist;
• 8 die Ausleitung der Testbehältnisse;
• 9 eine Ausgestaltungsform der erfindungsgemäßen Vorrichtung, bei der die Inspektionseinrichtung örtlich nach der Druckmaschine angeordnet ist;
• 10 eine schematische Darstellung einer erfindungsgemäßen Vorrichtung mit erforderlichen Sensoren.

In it show:

• 1 a schematic representation of a device according to the invention;
• 2nd a representation of a device according to the invention, in particular the printing press;
• 3rd RIP files or the associated masterprints of successive print jobs;
• 4th RIP files with exemplary defined printing errors;
• 5 an embodiment of the device according to the invention, in which the coding is applied in the printing press;
• 6 an embodiment of the device according to the invention, in which containers with coding are introduced into the printing press;
• 7 an embodiment of the device according to the invention, in which the inspection device is integrated in the printing press;
• 8th the rejection of the test containers;
• 9 an embodiment of the device according to the invention, in which the inspection device is arranged locally after the printing press;
• 10th is a schematic representation of a device according to the invention with necessary sensors.

1 shows a schematic representation of a device according to the invention 1 for printing on containers 10th . The device 1 consists essentially of the printing press 12th . It shows a carrier 24th on that with respect to an axis of rotation D is rotatable and part of a transport device 2nd is. There are holder devices on this support 22 arranged which for holding the containers to be equipped 10th serve (only one shown). Furthermore are on the carrier 24th Printing units 4th , 6 , 7 arranged, but only three of these equipment units are shown. The reference numbers 14 , 16 and 17th each relate to control devices for controlling the printing units 4th , 6 and 7 .

At the in 1 The embodiment shown is a pressure unit which is attached to the containers 10th apply a direct print. These printing units 4th , 6 , 7 can have several printheads, for example three printheads, which are arranged one above the other. Furthermore, the device has rotation devices which allow each individual container 10th with respect to its longitudinal direction (which here is perpendicular to the plane of the figure) is rotated. Each printing unit can advantageously apply a color to the containers, for example cyan, magenta, yellow, black or white.

The reference number P indicates the circular transport path of the containers to be equipped 10th .

An inspection device is located downstream with respect to the holding elements and the equipment units 8th arranged, which checks the containers. For this purpose, the inspection device can be a storage device 32 in which reference images are stored. Furthermore, the device has a comparison device 34 which compares the recorded images of the test markings with the reference images.

2nd shows a representation of an embodiment of a device according to the invention 1 with a printing press 12th for printing successive, from a transport device 2nd , for example via a feed device 28 , supplied and removed containers 10th . The printing press 12th has various printing units 3rd , 4th , 5 , 6 and 7 on what ink of different colors on the container to be printed 10th apply. So brings the printing unit 3rd white color on the printing unit 4th yellow color, the printing unit 5 magenta-colored ink, the printing unit 6 cyan ink and the printing unit 7 black-colored ink on the container to be treated 10th on. One (or each) printing unit 4th , 5 preferably has a printhead 19th , a control device 14 (Pressure control) and an ink tank 20th on.

3rd shows a schematic representation of a printing press with several RIP files 40 . From the set of RIP files shown 40 (Image elements), several different image elements can be produced by combining or combining these, or several image elements can also be printed on a container. Here is the set of (to be printed) picture elements, preferably as a RIP file 40 are present in the storage device 44 a printing unit 4th and/ or a printing press 12th filed. Reference numerals 19th identifies a print head of the printing unit 4th who is in the works and drops of ink 42 whose size is also preferably from the printing unit 4th can be varied on the container to be printed 10th (not shown).

It can be seen that the RIP files are already from successive print jobs. The print jobs are loaded into the printing machine's print heads in good time. So a quick job change is possible.

The RIP files 40 are also sent to a storage device 32 the inspection facility 8th to hand over. During an inspection of the container 10th can do that on the container 10th located print image from a comparison device 34 (not shown) with those in the storage device 32 stored RIP files can be compared. Here too, the corresponding detections must be loaded in good time for a job change.

4th shows a container 10th by a printing unit 4th is printed. Here too are the storage devices 44 , the printhead 19th and the ink drops 42 to recognize. In the storage device 44 of the printing unit 4th various RIP files 40 loaded. While the reference number 40 The RIP files show the actually correct print image 40a-40f one print image each with a specific (exemplary) error. So shows 40a a printed image shifted in the y direction, 40b shows a print image that is too weak, 40c shows an incorrect resolution of the print, 40d a bad color, 40e an incomplete print image (as occurs, for example, in the event of a nozzle failure) and 40f a blurred printed image.

5 shows in front of the printing press 12th neutral containers 10th without test coding. In the printing press 12th the print job is processed and additional test containers 100 with specific errors and test codes 18th generated. It would also be possible (not shown) that some test containers 100 with the test coding 18th be provided, but a correct print image is printed without errors.

6 shows a setup similar to 5 . The difference, however, is that some of the containers 10th even before entering the printing press 12th with a coding 18th are provided. This coding 18th initiates the test run, i.e. the printing press 12th processed these containers in test mode, in particular attaching specific errors to the containers.

7 shows a printing press 12th with an integrated inspection device 8th . The test containers are located downstream 100 also by a diversion device 26 separated from the production stream. It is also possible that the diversion device 26 only after a post-treatment unit, such as B. an independent curing unit is arranged.

8th shows two possible alternative locations where the diversion device 26 can be arranged. So it would be possible, on the one hand, the diversion device 26 after the press 12th to arrange. As an alternative, however, it is also conceivable for the diversion device 26 into the press 12th integrate so that the separation of the test containers 100 from the production flow through the printing press 12th is made.

9 shows the arrangement of the inspection device 8th after the press 12th . In this variant, container handling is carried out independently of the printing press. The test containers are shown in the illustration 100 from a downstream of the inspection facility 8th downstream diversion device 26 diverted. However, the diversion device would also be conceivable 26 into the inspection facility 8th to integrate (drawn in dashed lines). In this case, the inspection facility would be located immediately 8th no test containers 100 more in the production stream.

10th shows a printing press again 12th , an inspection facility 8th and a diversion device 26 . The rejection device also makes the test containers here 100 from the containers 10th sorted out in production mode. In the printing press 12th is a sensor 36 arranged the coding 18th can read. This is especially necessary when in the printing press 12th already test containers with coding 18th be introduced. Also in the diversion system 26 is a sensor 38 arranged the coding 18th can read. This ensures that all test containers 100 can be diverted. Reference numerals 46 indicates a test run control. This test run control 46 interacts (represented by arrows) with the printing press 12th , the sensors 36 and 38 , the inspection facility 8th and the diversion device 26 .

The applicant reserves the right to claim all of the features disclosed in the application documents as essential to the invention, provided that they are new to the prior art, individually or in combination. It is further pointed out that features that may be advantageous in themselves were also described in the individual figures. The person skilled in the art immediately recognizes that a certain feature described in a figure can be advantageous even without the adoption of further features from this figure. The person skilled in the art also recognizes that advantages can also result from a combination of several features shown in individual or in different figures.

Reference list

1

contraption

2nd

Transport device

3, 4, 5, 6, 7

Printing units

8th

Inspection facility

10th

container

12th

Printing press

14, 16, 17

Control device for printing units

18th

encoding

19th

Printhead

20th

Ink tank

22

Holding device

24th

carrier

26

Diversion device

28

Feeding device

32

Storage device

34

Comparison device

36, 38

Test coding sensors

40 (a-f)

RIP file

42

Ink drops

44

Storage device of a printing unit

46

Test run control

100

Test container

P

Transport path

D

Axis of rotation

Claims (10)

Method for printing objects and in particular containers (10), the containers (10) being transported along a predetermined transport path (P) and at least temporarily being printed on their outer surface by means of at least one printing unit (4, 6, 7), the printed ones Containers (10) are inspected by an inspection device (8), characterized in that the printing units (4, 6, 7) receive modified printing commands at least temporarily in a test mode and containers (10) are printed at least temporarily by these modified printing commands in such a way that at least one of the containers (100) printed in the test mode differs from the containers (10) printed in a production mode in at least one feature of the actual printed image, and the containers (100) printed in the test mode are subsequently inspected by the inspection device (8). Procedure according to Claim 1 characterized in that the modified print commands generate a print image that corresponds to the print image as it is generated due to typically occurring errors in printing processes. Method according to the preceding claim, characterized in that containers (100) with a printed image are also generated in the test mode without typically occurring errors. Method according to at least one of the preceding claims, characterized in that the inspection device (8) inspects the printed containers (100) in a test mode in the same way as in a production mode. Method according to at least one of the preceding claims, characterized in that the containers (10) printed in a test mode are provided with a code (18) which identifies them as test containers (100). Method according to at least one of the preceding claims, characterized in that the containers (100) coded as test containers are sorted out after the inspection, regardless of the result of the inspection device. Method according to at least one of the preceding claims, characterized in that the inspection device (8) compares the printed containers (10) with a stored reference image. Method according to at least one of the preceding claims, characterized in that the inspection device (8) distinguishes different types of errors in the printed image when inspecting printed containers (10). Device (1) for printing on objects and in particular containers (10), with a transport device (2) which transports the containers (10) along a predetermined transport path, with at least one first printing unit (4, 6, 7) which is suitable for this and is designed to apply a pressure on an outer wall of the container (10), and characterized with at least one inspection device (8), characterized, that the containers (10) can be printed at least temporarily by modified print commands in a test mode such that at least one of the containers (100) printed in the test mode differs from the containers (10) printed in a production mode in at least one feature in the actual print image, and wherein the containers (100) printed in the test mode can be inspected by the inspection device (8). Device (1) according to the preceding claim, characterized in that the device (1) has at least two printing units (4, 6, 7).

Images