Offset Printing: Drying Time (Typical Example)
It takes time for ink to set on YUPO and consequently drying will take longer than with coated paper. Average drying times for single-sided printing will vary according to pattern, printing conditions, climate and a variety of other factors, however the following is a list of approximate drying times.
| FEB | FGS | FRB | FRR | ||
|---|---|---|---|---|---|
| Printing surface | Double-sided | Double-sided | Single-sided | Single-sided | |
| Ink used | Synthetic Paper Ink YUPO Ink UV Ink |
YUPO Ink UV Ink |
Standard Ink Synthetic Paper Ink YUPO Ink |
Standard Ink (Color Weight 200%) Synthetic Paper Ink YUPO Ink |
|
| Drying time (using YUPO Ink) |
100% | 1 to 2 hours | 4 to 6 hours | 1 to 2 hours | 1 to 2 hours |
| 200% | 2 to 3 hours | 5 to 8 hours | 1 to 3 hours | 2 to 3 hours | |
| 300% | 3 to 5 hours | 8 to 12 hours | 2 to 4 hours | 3 to 5 hours | |
| 400% | 5 to 7 hours | 10 to 16 hours | 3 to 5 hours | 5 to 7 hours | |
| Finish | Front | Semi-gloss | Matte | Semi-gloss | Semi-gloss |
| Back | Semi-gloss | Matte | Matte | Matte | |
In order to maintain the above-listed drying times, use fresh inks, do not allow ink to over-emulsify, and strictly follow the instructions about the dampening water. If the ink has still not set 24 hours after printing, it is likely that the ink has over-emulsified.
- The above average times are for relatively balanced designs in situations where no problems such as over-emulsification of ink have occurred.
- There is not a large difference in drying time for single-color printing and multi-color printing drying times for YUPO, so a multi-color press should be used whenever possible.
- If ink becomes over-emulsified, drying times will be significantly longer than the above-listed drying times, dependent upon the degree to which the ink has over-emulsified. Most problems with poor drying of YUPO are not caused by YUPO but by over-emulsification of ink.
- Low temperatures will cause longer drying times. Drying times will be significantly longer at temperatures less than 15℃.
- Drying time for the second printing surface (back side) in double-sided printing may be longer than that for front side printing. They will vary according to pattern and conditions. This is because the gas created when the ink on the first surface dries changes the quality of the back surface.
The following items are effective for shortening ink drying times.
- (1) Dry printed materials in a high-temperature (25 to 30℃) environment.
- (2) Frequently ventilate the drying area after the ink sets.
Carry out additional or rear-surface printing after the surface temperature of the paper returned as close as possible to the surface temperature at the time of the first printing. This is in order to avoid any registration errors.