functionality back

 

Function:

By switching on the flexographic printer, a diaphragm pump (A) transfers the ink from a container (B) to the ink unit. The ink will be carried over from the steel roller (D) and transferred to the ink roller via the rubber roller (E). The printing cycle is released by the paper advance of the packaging machine. Starting from approx. 70 mm film advance the sensor of the roller starts the dyeing of the ink roller. (The printing can also be triggered via a external contact) The ink roller will move forward and roll backwards over the cliche thereby applying an thin layer of ink. By means of a pneumatic cylinder the print plate will be pressed against the top web, thereby transferring the ink to the top web. In the meantime the print roller has been reinked.

 

The ink unit:  
The ink unit with diaphragm pump (A) and a sensor for maximum filling level is fixed at the backside of the printer. The reservoir (B) for the ink is fixed at the side wall of the packaging machine, as near as possible to the below side of the ink unit. The diaphragm pump supplies the ink via the hose (C) from the reservoir into the ink tub. When the steel roller (D) is turning, ink flows onto the rubber roller (E) where the surplus of ink is squeezed off. The result is a thin and even film of ink which is transferred on to the ink roller (F). The remaining ink flows back in to the reservoir via the return hose (G). For reasons of security there is a sensor for the surveillance of the ink level. If the return hose is blocked, the diaphragm pump stops automatically. At the front side of the printer flashes a red light; the LED at the sensor is on. The printer goes on working but does not give any "READY" signal impulse back to the packing machine. Press ON after removing the blockage to re-activate the diaphragm pump. At first the operation reservoir has to be filled with ink and a little thinner. Choose the mixture by the required contrast. The more thinner you add, the lower the contrast will be. Always check that enough ink is in the supply container. If ink and thinner are not refilled for a long period of time then the solvent evaporates and the ink becomes stringy. This condition becomes first apparent when large imprints are produced on the paper. The printed letters, numbers, and images will have darker edges than usual and certain characters may become illegible. In the before mentioned condition the drying time of the ink is substantially prolonged and thinner or ready-mix ink should be added. Ink which has become thick and stringy may cause interruption in service and should be avoided (i.e. longer drying time, smearing of images, ink contamination on all guide rollers in the system, bleeding of ink through the printed film). Cleaning of the print plate and guide rolls may be necessary to restore a proper print image on the film.

 

Shut-down

At a normal stoppage time of a maximum of one week, no further actions are necessary. With stoppages of more than a week (e.g. holidays), hoses have to rinsed through with thinner. Otherwise the ink will dry out in the hoses and can cause a blockage. This can be done with the secondary reservoir (filled with some thinner). Rinsing should not take less than 5 minutes. It is possible to add thinner to the ink during production. Now the printer can be turned off. Before holidays we recommend to clean the ink unit and to reinsert it before re-start to avoid tender spots on the rubber roller.

 

Start-up after prolonged Shut-down

Unless the ink unit has been thoroughly cleaned prior to a prolonged shut-down (more than a week) the ink will dry out and cake up the various rollers. To avoid damage to the gears the following steps are recommended. - remove inking unit - rotate rubber roller several times by turning gear by hand. - reinsert inking unit - turn printer ON for several minutes until all hardened ink starts to circulate normally. Ensure that the ink unit is completely seated and snapped into the proper position or printer will not start.

 

The diaphragm pump:  

The diaphragm pump is installed directly on top of the ink unit. The controler is integrated in the PLC of the printer and the pump is in operation as long the printer is ON except for a interruption produced by a blockage. The air regulator and the flow control valve are adjusted at the factory. Do not change the adjustment.

A
 pump cover
B
 rubber diaphragm
C
 air inlet
D
 ink inlet
E
 valve balls
F
 pump body
G
 ink outlet

 

 

Combined print plate  
1
 print plate
2
 sponge
3
 magnetic layer
4
 metal paper
5
 photopolymer cliche
6
 ribbed rubber base plate
7
 ribbed rubber cliche
8
 magnetic holder of print plate

 

 

Recommended Ink

To print on medical paper or TYVEK™, we recommend to use our standard ink R9 blue Art. No.: DV100 583 R9 black Art. No.: DV100 585 R9 red Art. No.: DV100 586 R9 green Art. No.: DV100 587 Thinner for R9 Art. No.: DV100 584 (standard unit: 5 liter container) It is an alcohol-based ink and is qualified to be used where gas or gamma sterilization is needed. For steam sterilization we recommend to use our ink type 8080 in series.