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If you could single out the most common cause of water balance problems it would be deteriorated dampening rollers. Press owners and operators sometimes have false expectations regarding the useful life of these critical press components.
While most of the parts which make up an offset press are subject only to physical wear, rollers must sustain the added threat of oil, grease, ink, press wash, and several other chemicals and compounds. Even the best quality rollers will succumb to the punishing effects of normal use.
Even if the roller surface looks to be in good condition you need to pay close attention to the ends. End swelling is the most common form of roller problems. Over time both ink and chemicals are able to penetrate this most vulnerable portion of the roller. They cause the rubber to swell, making the roller ends expand to a larger diameter. This has the effect of lifting the center area of the roller up and off the plate, reducing the flow of fountain solution. (The situation is just as bad with ink rollers, with reduced ink reaching the plate).
You can quickly and easily determine if your rollers are swollen. Remove the dampening cover and place the roller on a flat clean surface. Place an metal ruler edge upright along the length of the roller surface and peer between the ruler and the roller. If you can see daylight through a gap, the ends are swollen. It's time to replace the roller.
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