Banding Characterization for Inkjet Printing

A significant challenge for developers of inkjet printing technologies is achieving uniformity in areas of solid color. Non-uniformities can generally be classed as either twodimensional, including such phenomena as graininess, coalescence and mottle, or one-dimensional, usually termed banding. Banding is often the most objectionable print quality problem in digital prints. Much research has been done into human perception of banding, but developers of digital printing systems have typically not had access to test equipment that would allow them to capitalize on this work. In the absence of appropriately designed test methodologies, they have lacked the means to quantify banding in their products, either by tracking progress in product development or monitoring banding in production. Enough is now understood about banding measurement for practical steps to be taken to address this widely-recognized problem. This paper will discuss banding measurement from a practical engineering perspective, based on a technique implemented in a commercially available print quality analysis system. The discussion will focus on how this technique can be applied to inkjet printer development, identifying key factors affecting banding and describing “metrics” for quantifying its magnitude. Progress in developing an international standard for banding measurement, and its importance in the context of existing standards, will be discussed.