As the mechanical inaccuracies of the inkjet printers are an order of magnitude worse than the inaccuracies of imagesetters and CTPs, there are several quality problems on inkjet printers.

The most offensive problem is banding, caused by two mechanical problems:

· nozzle inaccuracy: each nozzle places the droplet consistently with approximately the same error (i.e. the same distance in the same direction from the required position of the droplet).
· feed inaccuracy: the paper isn't fed by exactly the required amount.

The banding is caused by the fact that compact bands on the media (typically one or more neighboring rows of pixels) contain droplets with the same placement error (e.g. 5 microns above their required position), and beside it is another narrow band of pixels containing droplets with another, different placement error (e.g. 3 microns under their required position), as shown on the first picture. The human eye will perceive this as an offensive banding.

To suppress this banding, a special interlacing technique is used. The idea is to break up the bands in as many ways as possible: ideally each pixel should have its own placement inaccuracy, independently from its neighbors, as shown on the second picture. The human eye will perceive this as a uniform visual noise rather than banding, and on good quality printers, using light inks, the noise is practically unperceivable.

Breaking up the bands is done by printing neighboring pixel rows with different nozzles, or even the same row with several different nozzles. At the same time, mechanical inaccuracies are minimized by feeding the paper by exactly the same amount each time.

Printing the same pixel row with more than one nozzle is particularly interesting, because it can improve the quality at the expense of the printing speed (usually printing at about half the maximum speed but giving dramatically improved results). On the other hand, as some RIPs use their own algorithms for selecting the different nozzles for the same row, there are quality differences between different RIPs with respect to banding. (StudioRIP claims better results than other RIPs when using Epson printers.)