Back side Ghosting (Migration)
The phenomenon when ink transfers irregularly in various locations when printing on the rear side of a double-sided print sheet or ink drying times increase is called back side ghosting. This happens because a gas that is produced by the first-printed inks drying changes the properties of the rear printing surface of the YUPO when it comes in contact.
There are no perfect remedies when this problem occurs, so be sure to implement the following preventive measures in advance.
Preventive measures
- Be sure to use the specified YUPO ink.
- Be sure that the side having sparser image content is printed first.
- Do not add drier to the inks to be used for the first-side printing.
- Once the first-side inks have set, be sure to ventilate the YUPO sheets as soon as possible and as frequently as possible.
- Once the first-side inks have dried, be sure to print the rear side as soon as possible (within 24 hours at the latest).
- It is effective to add an EX drier (T&K TOKA) or an X + Y = DRY drier (LOHAS PRINT) to enhance drying of the ink on the rear surface. Also, once the inks have set, ventilate the sheets immediately and as frequently as possible.