Let’s take a look at the top three things that you need to do regularly to maintain your rollers
Rollers are a critical part of your press. In fact, they are the key to maximizing your print output. Unless your rollers are in good shape, you will not be able to achieve the desired printing results. Yet, most people don’t know how to take care of their rollers properly.
Here are some of the maintenance activities that you should carry out regularly to ensure that your rollers stay in good condition:
Use a roller setting strip for setting rollers
Incorrect roller settings can impact your rollers negatively by putting too much or too little pressure on them. There are a series of inking and dampening rollers which are driven by the roller train. They are driven by friction, which in turn depends on the setting. If you have a higher setting, then your machine has to work harder to drive the complete train, thereby exerting greater pressure on the rollers. This excessive pressure may eat away your rollers faster. If the pressure is too light, the chances of slipping are higher, and you will get streak marks on your prints.
Most printers are under the impression that the greater the roller pressure, the better is the print quality. This is nothing but a myth. It is not mere pressure which is causing the ink to grind. Ink grinds by shear force generated by the different speeds of rollers with different diameters. Surveys show that excessive pressure settings use 25-27% more ink. As a matter of fact, the right pressure setting can help you save on the amount of ink consumed (by 27%), fountain solution (by 15%), wear and tear on plates (by 9%). It also reduces the load on your motor, thereby saving energy. But most importantly, it gives you better quality prints.
There are special roller setting strips available that can tell you how much pressure there should be set between the rollers. Always follow the manufacturer’s instructions, and use a roller setting guide. This not only prevents undue damage to your rollers, but also ensures consistent print quality.
Check surface condition of dull chrome distributor roller in the dampening system
If the surface of the dull chrome distributor in your press’ dampening system cannot hold liquid, it will not be able to transfer ink properly.
Perform this simple test to check the surface condition of your dull chrome distributor roller: apply three or four drops of fountain solution on the surface of the roller, and wait for five seconds. The roller should be able to hold the drops and not let them slide off. If the drops slip off completely, then this means that the roller does not have holding capacity and will not be able to carry out proper ink transfer.
You should also frequently remove the dampening form roller and clean the dull chrome roller thoroughly. Apply a thin film of gum and dry it before putting it back.
Check the shore hardness of your rollers
Rollers are spongy. The harder they get, the lesser will be their grip. When seen under a microscope, the roller surface should show a pattern that resembles hills and valleys. The roller’s grip and hardness have to be proper and as per the manufacturer’s instructions. That is why Heidelberg recommends that you use original rollers. The hardness, the quality of rubber, the hills and valleys, carrying capacity, all these factors are compromised with, when you choose to get rollers from superfluous sources.
To check the shore hardness of your rollers, measure the hardness at three or five points. The average of these values will give you the hardness of the roller.
Just like any other piece of equipment, your rollers also need to be monitored and maintained periodically, with several activities performed at regular intervals. Creating and sticking to a schedule for maintenance activities, which includes such activities as roller cleaning, deglazing, decalcifying, checking settings, etc, can ensure that your rollers stay in the best possible condition and last a long, long time.