Alignment Failure
Print alignment failure denotes the incorrect positioning of consecutive ink colors on a moving substrate during a multi-unit printing run. An offset press misregister occurs when the cyan, magenta, yellow, and black ink stations fail to deposit their images on the exact same spatial coordinates of the paperboard sheet. This deviation results in a blurry or double image, making text unreadable and altering the intended color balance of graphics.
Modern packaging demands high-precision registration to ensure barcodes and fine text are crisp and scannable.
Substrate Behavior
Paperboard absorbs water from the dampening solution in each offset printing unit, which can cause the fibers to swell between printing stations. This dimensional change occurs rapidly and is more pronounced in the cross-machine direction of the paperboard. When the sheet expands as it travels through the press, the images applied by the downstream printing units do not align with those applied by the upstream units.
Standardizing the moisture content of the board and controlling the pressroom temperature reduces this substrate behavior.
Register Control
Press operators utilize automatic camera systems that scan register marks printed on the waste area of the sheet. These sensors detect deviations as small as a fraction of a millimeter and send correction signals to the cylinder drives. Quick adjustments to the plate cylinders or sheet transport timing bring the colors back into alignment.
