Full-length applicators in addition to / instead of dovetail applicators
Full-length applicators, as an alternative to standard dovetail applicators, are advisable when printing at high speed with great repeats (> 600 mm) or when using easily-drying inks with the tendency to fill the etching’s cell and retarders can’t be used.
Under such conditions, the full-length applicator wets the cylinder’s surface immediately after the print, i.e. after the cell has been emptied by the material pressed on it with the impression roller. After print, the cell still holds little ink quantities which may dry up if exposed to air for a long time. The full-length applicator, by wetting the printing cylinder’s surface, shortens the cell’s exposure time to the air, thus reducing the drying effect on the ink held by the cell. Furthermore, the immediate wetting of the cylinder with new ink softens the remaining, and drying, ink in the cell, if any. The ink layer distributed by the applicator must be uniform and really “sticking” to the printing cylinder’s etched surface. Under this condition it will be possible to print for a long time without dry ink inside the cell (and, as a consequence, without quality degradation in the printing point).
Full-length applicators, as an alternative to standard dovetail applicators, are advisable when printing at high speed with great repeats
With the dovetail applicator instead of the full-length one, the cell’s exposure time to the air is three times as much, since the applicator is located under the ink level inside the pan, causing a higher evaporation of the ink still held in the cell, if any, and the subsequent dry ink sedimentation.
The installation of the full-length applicator on the printing trolley is possible on all press models, including the R940. On the latter, the installation aboard the trolley is possible only from job numbers 2975 and 2993 onwards, because their side frames on operator side have a wider passage allowing the trolley, housing the applicator, to pass through them. On older R940 presses the full-length applicator is installed on the side frame itself, and not on the trolley.
- Job n. 3512 – Modification on job n. 1948, Model R138
- Intervention: january 2005
- Job n. 3631k – Modification on job n. 3631, Model R962
- Intervention: may 2007
- Job n. 3804 – Modification on job n. 3747, Model R980
- Intervention: april 2009
The intervention consists in supplying the full-length applicators and the assembly drawing for the installation aboard the trolley.
1) great reduction of dry ink sedimentation
2) better printing quality, halftones included
3) better printing quality also when using metallic inks