Anilox inking unit for a rotary offset printing machine

#1. Field of the Invention

#The invention relates to printing machines, and more particularly to an anilox inking unit for a rotary offset printing machine.

#2. Description of the Related Art

#In the drawings wherein like reference numerals denote similar elements throughout the views:

#FIG. 1 is a side view of an anilox inking unit;

#FIG. 2 is a partial perspective view of a first modified embodiment of the anilox printing unit of FIG. 1;

#FIG. 1 shows a side view of an anilox inking unit which is arranged on a printing unit. The plate cylinder 1 and the transfer cylinder 2 of the printing unit are illustrated. An applicator roll 3 is in contact with the plate cylinder 1 and is also in contact with an anilox roll 4. It is also possible for a number of applicator rolls to be arranged between the plate cylinder 1 and anilox roll 4. Furthermore, an indirect connection between the applicator roll 3 and the anilox roll 4 via an intermediate roll is possible. The term screen roll is also commonly used for the anilox roll 4, since dimples which can be filled with ink are arranged on its surface in the manner of a screen grid. A chamber-type doctor 5 is brought into contact with the anilox roll 4 and is connected to an ink trough 6. A nozzle bar 7 with nozzles 8 arranged alongside of one another in the longitudinal direction of the anilox roll 4 is installed along the anilox roll 4, downstream of the chamber-type doctor 5 in the direction of rotation. The nozzles 8 are designed as holes in the wall of the hollow nozzle bar 7. And may also be designed as slots. A damping unit 9 is arranged on the plate cylinder 1.

#The printing unit prints a web 10 by means of the transfer cylinder 2, which interacts with an impression cylinder (not illustrated), for example with the transfer cylinder of a further printing unit. The transfer cylinder 2 receives the printing image to be applied to the web 10 from the printing plate of the plate cylinder 1. Plate cylinder 1 is dampened by means of the damping unit 9 and inked by means of the applicator roll 3. Printing ink is fed to the applicator roll 3 by means of the anilox roll 4, whose screen dimples are flushed and filled by the chamber-type doctor 5. The printing ink is pumped to the chamber-type doctor 5 from the ink trough 6 by means of an ink pump (not illustrated). As viewed in the direction of rotation of the anilox roll 4, the chamber-type doctor 5 terminates with a working doctor 11, which wipes excess ink cleanly off the filled anilox roll 4. Subsequently, the surface of the anilox roll 4, including the surface of its ink filling, has a fluid applied to it by means of the nozzle bar 7, any surface water which is present is removed by evaporation. In this and the following exemplary embodiments, the fluid is room or ambient air, with it also being possible to use specifically dried air or other fluids. The transfer of ink to the applicator roll 3 subsequently takes place at the point of contact 12 between the anilox roll 4 and the applicator roll 3. Optionally arranged upstream of the chamber-type doctor 5, in the direction of rotation of the anilox roll 4, is a further blowing device 13, with which residual ink on the anilox roll 4 can be dried on the surface before it runs into the chamber-type doctor 5. It is also unnecessary for the working doctor to be integrated in a closed ink feed system, as a subsequent exemplary embodiment will show.

#For reasons of simplicity in the following exemplary embodiments, the previous item numbers will largely be maintained in the case of repeating components. FIG. 2 shows only part of an anilox inking unit for a rotary offset printing machine. The plate cylinder 1, the applicator roll 3 and the anilox roll 4 are shown. The plate cylinder 1 or the printing unit is four pages wide. Four pipes 14 to 17 are arranged on the anilox roll 4, downstream, in its direction of rotation, of the working doctor blade (not illustrated), each pipe covering the area of one page. Each pipe 14 to 17 has a slot nozzle which extends over its length and is directed towards the anilox roll 4, or a number of shorter slot nozzles. Furthermore, each pipe 14 to 17 is supplied via a line 18 with compressed air produced by a blower 19. A valve or throttling member 20 to 23 is provided in each of the feed lines to the respective pipes 14 to 17. The adjusting members of the valves 20 to 23 are each connected to an output of a control device 24. The inputs of control device 24 are in each case connected a sensor 25 to 28 which is respectively assigned to the area of one page of the plate cylinder 1 and senses the inking, for example the ink layer thickness. The sensors 25 to 28 may also be arranged on the transfer cylinder 2. On the anilox roll 4, there is also an inking device (not illustrated), for example a chamber-type doctor.