HW is a high grade dampening roller designed for Environmentally-friendly inks such as
Non-aromatic inks and Vegetable-oil based inks as well as Conventional oil-based inks.
Environmentally-friendly inks often have negative effects on rubber rollers such as
insufficient water supply, diameter shrinkage, need of frequent nip-adjustment and
shorter lifetime. HW has overcome such problems.
Features (Comparison with our existing grade, New W4 series)
1. Highly resistant to Eco-friendly inks, which offers minimal diameter shrinkage, nip-width change and hardness changes. Therefore, the life time will be longer.
2. No need of water dial adjustment from morning to afternoon because it can maintain its stable water supply property for a long time. Also, HW can absorb the bouncing against the plate cylinder when used as water form rollers.
3. Having excellent Tensile Strength, HW has a great durability.
4. Hydrophilicity is the same as New W4.
Hardness: 20, 25, 30 (Shore A)
Color: Violet
Performance
◆ Resistance to Vegetable Oil-based inks
Each rubber samples in 5 gram block are immersed in Soy-based inks. The weight of each is measured after certain period of time.
◆ Physical properties
| Material | ||
|---|---|---|
| HW-25 | New W4-25 | |
| Hardness (ShoreA) | 25 | 26 |
| 100% Modulus (Mpa) | 0.29 | 0.39 |
| Tensile strength (Mpa) | 6.47 | 5.73 |
| Elongation (%) | 900 | 800 |
| Tearing strength (N/mm) | 12.7 | 13.9 |
* These values are the representative values, not standard values.
* Tested under JIS K 6251 to 6253.
◆ Measurement of current of electricity (Load against dampening rollers)
We measured the current of electricity while running the press. Nip-width between Metering roller and Fountain roller is 4 mm. Printing press is Komori Lithrone 426.
| Material | HW-25 | New W4-25 |
|---|---|---|
| Before printing | 0.15 | 0.20 |
| During printing | 0.32 | 0.42 |
* Measured with Cramp type ammeter (20A) Unit: A
* Before printing means that only water fountain roller and water metering rollers are running.
◆ Hydrophilicity
After cleaning and drying rubber block surface by alcohol, we dropped 0.01 cc water on the surface. The water contact angles were measured immediately after drop, in 10 seconds and 30 seconds.
| Material | ||
|---|---|---|
| Contact angle | HW-25 | New W4-25 |
| Immediately after drop | 102 | 110 |
| After 10 seconds | 96 | 96 |
| After 30 seconds | 72 | 74 |
* Measured with Contact angle finder, CA-D type Unit: deg.