EP2444248B1 - Tampon printing press and method for at least two-stage printing of an object - Google Patents

Description

The invention relates to a pad printing machine for at least two-stage printing of an object, with a machine frame on which at least one printing pad carrier and at least one plate carrier are mounted for at least two plate areas and with a camera and a computer for evaluating the images generated by the camera.

Such pad printing machines are known in the prior art in numerous designs. They have several clichés and corresponding inking, which allow in particular a multi-color print. It is also possible a multi-step printing of an object with the same printing ink.

In order for accurate printing to be possible, the pad printing machine must be set so that the respective prints are printed correctly relative to one another on the object. This was done manually for a long time by repeatedly printing and shifting the pressure levels. Such a setup is very expensive and requires to set up a specially trained professional.

Pad printing machines have also become known in which this setting is assisted by a camera. For example, the shows DE-A-10 2008 029 299 a tampon printing machine having a plurality of plate carriers, which are arranged on a turntable. The ink absorption and color output is done with printing pads, which are arranged on a carousel-like printing unit carrier. With an image pickup device in the form of a CCD camera images of the respective Cliché area generated. In the comparison device, the generated images are compared in an evaluation device with reference data. As a corrective measure, the clichés are brought into a desired position or the deviations from the desired value are stored, so that the wearer of the object to be printed can drive to its optimum position in each pressure stage.

By the DE-A-10 2008 021 300 a tampon printing machine has become known which has a positionally variable support for the object to be printed. In addition, a Einricht-print image recording is provided, which is arranged immovably to the said carrier in the distance and in the position. With an image pickup device, images of at least a portion of the setup print image pickup device are generated.

The invention has for its object to provide a method and a pad printing machine, which allows an even easier setting.

According to the method, the invention is achieved by printing at least one registration mark on the object to be printed in order to set the printing with the printing pad, recording an image of the printed registration mark with the camera and storing correction values and, on the basis of these correction values, the printing positions of the at least two Cliché areas are corrected. In the case of the pad printing machine according to the invention, provision is accordingly made for the camera to be arranged in such a way that it can produce an image at least of a partial region of an object to be printed. In the method according to the invention, the adjustment thus takes place directly on the printed image or on the object to be printed. It is essential that in the method according to the invention or the pad printing machine according to the invention the printed image correction is independent of where the errors to be corrected come from. It can thus be considered all tolerances. This makes it possible to achieve an even more precise pressure. The setup can be done relatively quickly and without special expertise.

According to a development of the invention, it is provided that the plate carrier is arranged on an adjusting unit, which is adjustable in the X direction and Y direction. This allows printing with only one tampon. This is cleaned after each pressure on a cleaning device.

According to a development of the invention, it is provided that the printing pad carrier for ink pickup and ink delivery in the X direction is movable centrally to a machine axis. When printing a color, the corresponding cliché is moved to the machine axis and positioned there. The tampon transfers color from the cliché to the object to be printed by moving in the Y-axis. Angle of rotation errors, which can hardly be avoided with carousel-like printing units, can not occur here. In addition, a stable storage of the printing pad carrier, in particular on an arm of the machine frame, is possible. By linear movements of the printing pad between the adjustment or the corresponding cliché and the object to be printed and a cleaning device can be moved. The said arm preferably extends over a displacement unit, the cleaning device and a receptacle for the object to be printed.

The adjustment is carried out according to an embodiment of the invention in two adjustment cycles or modes. In the first cycle, the correction values are determined with respect to the Y-axis of the adjustment unit. This is also done by printing registration marks on the object to be printed and an evaluation with the camera. In a second setting cycle, the correction values for the individual cliché areas are determined and stored. During printing, the object is preferably fixed, while the adjustment unit, taking into account the corresponding correction values, positions the corresponding cliché for color pickup. A firmly positioned object can then be printed several times with a single tampon.

Further advantageous features emerge from the dependent claims, the following description and the drawings.

Fig. 1

eine räumliche Teilansicht einer erfindungsgemässen Tampondruckmaschine,

Fig. 2

schematisch eine Draufsicht auf die erfindungsgemässe Tampondruckmaschine,

Fig. 3

schematisch das Bedrucken eines Objektes mit zwei Passermarken und

Fig. 4

schematisch eine Seitenansicht der erfindungsgemässen Tampondruckmaschine.

An embodiment of the invention will be explained in more detail with reference to the drawing. Show it:

Fig. 1

a partial view of a part of a tampon printing machine according to the invention,

Fig. 2

schematically a top view of the pad printing machine according to the invention,

Fig. 3

schematically the printing of an object with two registration marks and

Fig. 4

schematically a side view of the novel pad printing machine.

The pad printing machine 1 has according Fig. 1 a machine frame 10 having a horizontally extending arm 9. This arm extends towards the in Fig. 2 Below the arm 9, a displacement unit 6, a cleaning device 8 and a receptacle 2 are arranged. On the arm 9, a pressure pad carrier 3 is mounted on the underside, according to the double arrow 18 in Fig. 2 is mounted in the directions of the machine axis A centric to this displaceable. The shift takes place with a drive, not shown here, which is housed for example in the arm 9. At the printing pad carrier 3, a printing pad 4 is fixed, with which a fixed object 2 on the receptacle 17 can be printed. To set up the receptacle 2, an adjusting device 14 is provided. When printing the recording 2 and accordingly also the object 17 is not moved. The object 17 is thus preferably immobile during printing. The receptacle 2 is formed according to the object 17 to be printed. Such recordings are known per se to those skilled in the art.

The displacement unit 6 has a plate 15 which is arranged on a high-precision bearing 13 and according to Fig. 2 is displaceable in the directions of the double arrow 19. With two mutually spaced knurled screws 24 ( Fig. 2 ), the plate 15 can also be adjusted when setting in the directions of the double arrow 18. This setting is done by hand. The directions of the double arrow 19 are perpendicular to the directions of the double arrow 18. The drive 16 is also highly precise and is controlled by a computer 23 connected to an operator panel 11 in which data can be entered. On an upper side 7 of the plate 15 are several, for example, as shown, four plate carrier 5 is mounted. On each of these plate carriers 5 is a cliché 20, which can be colored in a conventional manner in each case with a paint pot 12. The coloring takes place by movements in the directions of the double arrow 18.

The bearing 13 is formed so that the plate 15 with the plate carriers 5 and the ink pots 12 together in the directions of the double arrow 19 is controlled displaced is to position the clichés 20 respectively for the printing and the color recording. The clichés 20 are each arranged centrically to the machine axis A. The tampon 4 can then be picked up by the correspondingly positioned cliché 20 and transferred to the object 17. After printing on the object 17, the printing pad 4 is raised and moved to the cleaning device 8 and cleaned by a corresponding stroke. The cleaning device 8 may, for example, have a roller 21, from which a cleaning paper (not shown here) can be pulled off. Such cleaning devices 8 are known per se to those skilled in the art. If the printing pad 4 is cleaned, it is raised again and moved centrically to the machine axis A to the displacement unit 6. By lowering the pressure pad 4 color is now picked up by another cliché 20 and in turn transferred to the object 17. After each color pickup, the plate 15 is shifted so that a cliché 20 is positioned on the machine axis A for the next color pickup. The clichés 20 are thus successively positioned centrically on the machine axis A for color pickup.

If the object 17 is printed with all, in this case with four colors, the object 17 is removed from the receptacle 2 and optionally replaced by another object to be printed. When printing the object remains 17, as already mentioned, preferably fixed and will not move. When printing thus only the printing pad 4 and the plate 15 are moved. After each printing, the plates 20 are colored again by the above-mentioned movements of the paint pots 12. With a single pad 4 can thus be printed several times with the pad printing machine 1 according to the invention. The linear movements of the tampon 4 and the printing pad carrier 3 centric to the machine axis A allow a particularly precise pressure.

On the machine frame 10, a camera 22 is attached, which according to the Fig. 2 for a signal transmission to the computer 23 and to the drive 16 is connected. The camera 22 is directed so that it can take 17 pictures at least of a partial area of the object to be printed. The camera 22 is thus directed against the receptacle 2 out. Of course, the camera 22 can be mobile, so they can be set up accordingly. The camera 22 is, for example, a CCD camera or other suitable recording device.

The camera 22 is used to set the pad printing machine 1. When setting 4 register marks PA, PB, PC or PN are printed on the object 17 with the pad. Each register mark PA, PB, PC or PN is assigned to a cliché 20. Such registration marks, which are formed for example as crosses, are known per se to those skilled in the art. With the camera 22, the register marks printed on the object 17 PA, PB, PC or PN can be recorded. On the basis of these recordings, corresponding correction values are calculated and stored in the computer 23. The adjustment preferably takes place in a first setting cycle and in a second setting cycle. In the first setting cycle, only two registration marks, such as the registration mark PA and the registration mark PN, are printed on the object 17, and based on the determined Y-axis correction values, the plate 15 is adjusted on the thumbscrews 24 or other suitable adjustment means. In the second cycle, each individual cliché 20 is measured with respect to the necessary corrections and stored in the computer 23 with corresponding individual corrections. A manual adjustment is not provided here. These two cycles are explained in more detail below.

1st setting cycle

First, the pad printing machine 1 is brought into the setting mode and the corresponding program is started on the operator panel 11. The actuator 16 positions the cliché A by shifting in the X-axis and Y-axis to a position A (X) / A (Y). The cliché 20a is thus positioned here on the machine axis A. The cliché 20a is now flooded with paint and the pad 4 picks up the register PA. By moving the tampon 4 in the Y direction, the register is printed on the object 17. The camera 22 now captures an image of the print and, in particular, the printed register PA and calculates the necessary corrections in the X direction and Y direction. The corresponding corrections A (X) / A (Y) are stored in the computer 23.

The register PA on the object 17 is now removed manually. The cliché N now moves accordingly to a position N (X) / N (Y). The cliché 20n is now also with Color flooded and the pad 4 takes the passer PN from the cliche N. The pad 4 now moves to the object 17 and prints on this the passer PN. The camera 22 now takes an image of the print and stores the determined correction values N (X) / N (Y) in the computer 23. The object 17 is cleaned again and thus the printed register PN is removed. The calculator 23 now calculates the difference of the Y-axis between A (Y-correction) and N (Y-correction). The calculated Y value is displayed on the operator panel 11. The knurled screws 24 are now readjusted manually by this value. As a check, the mentioned cycle can be carried out again.

2nd setting cycle

At the operator panel 11, the corresponding subroutine for this cycle is started. The cliché 20a is then moved to position A (X) and A (Y). The cliché 20a is now flooded with ink and the printing pad 4 picks up the register PA and transfers it to the object 17. The camera 22 now takes a picture of the print and stores the calculated correction values A (X) and A (Y). The pad printing machine 1 is now stopped and the register PA is removed from the object 17. The pad printing machine 1 is then restarted manually and the above-mentioned process is performed for each cliché 20. The corresponding correction values are again stored in the computer 23.

After setting up can be printed as usual. The clichés 20a, 20b, 20c and 20n are respectively positioned for color pickup according to these correction values. The clichés are thus traversed here in the X-axis or the Y-axis. The movement in the Y direction can be comparatively small accordingly.

LIST OF REFERENCE NUMBERS

1

Pad Printing Machine

2

admission

3

Pressure pad carrier

4

printing pad

5

plate holder

6

displacement unit

7

top

8th

cleaning device

9

poor

10

machine frame

11

control panel

12

paint pot

13

camp

14

adjustment

15

plate

16

drive

17

object

18

double arrow

19

double arrow

20

cliche

21

role

22

camera

23

computer

24

Screws

A

machine axis

P _A

first registration mark

P _B

second registration mark

P _C

third registration mark

P _D

fourth registration mark

Claims (12)

1. A pad printing machine for the at least two-stage printing of an object (17), with a machine frame (10), on which at least one printing pad carrier (3) and a printing plate carrier (5) for at least two printing plate regions (20) are mounted, and with a camera (22) as well as a computer (23) for evaluating the images generated by the camera (22) wherein the camera (22) is arranged so that it can generate an image at least of a part region of a printed object (17), and wherein the printing plate carrier (5) is arranged on a displacement unit (6), which is adjustable in X-direction and Y-direction, characterized in that the displacement unit (6) comprises means (24) on which the displacement unit (6) is manually re-adjustable with respect to the Y-axis.
2. The pad printing machine according to Claim 1, characterized in that the printing pad carrier (3) can be moved for ink absorption and for ink discharge centrically to a machine axis (A).
3. The pad printing machine according to Claim 1 or 2, characterized in that the printing plate regions (20) each have a register mark (P_A, P_B, P_C, P_N) .
4. The pad printing machine according to any one of the Claims 1 to 3, characterized in that the object (17) can be printed multiple times with merely one printing pad (4).
5. The pad printing machine according to any one of the Claims 1 to 4, characterized in that the printing pad carrier (3) is movably mounted on an arm (9) of the machine frame (10) which extends horizontally.
6. The pad printing machine according to Claim 5, characterized in that the arm (9) extends over the displacement unit (6) and the mounting (2) for fixing the object (17) to be printed.
7. The pad printing machine according to Claim 5 or 6, characterized in that it comprises a cleaning device (8) with which the printing pad (4) can be cleaned after each printing.
8. A method for the at least two-stage printing of an object with a pad printing machine according to any one of the Claims 1 to 7, characterise in that for adjusting the print with the printing pad (4) at least one register mark (P_A, P_B, P_C, P_N) is printed onto the object (17) to be printed, in that with the camera (22) the printed register mark (P_A, P_B, P_C, P_N) is recorded and correction values are stored and in that based on these correction values the print positions of the at least two printing plate regions (20) are corrected.
9. The method according to Claim 8, characterized in that the printing plate regions (20) are arranged on a displacement unit (6) which is adjustable in Y-direction and X-direction and which extends at a right angle to a machine axis (A).
10. The method according to Claim 9, characterized in that in a first adjusting cycle correction values with respect to the Y-axis of the displacement unit (6) are determined and in a second adjusting cycle correction values for the individual printing plate regions (20) are determined and stored.
11. The method according to Claim 9 or 10, characterized in that in the first adjusting cycle the displacement unit in (6) is readjusted manually with respect to the Y-axis.
12. The method according to any one of the Claims 9 to 11, characterized in that for readjusting the Y-axis, correction values of two outer printing plate regions (20a, 20n) each are determined.

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