In the printing industry, electrophotography (EP) is a commonly used technology in laser printers and copiers. In
the EP printing process, there are many rotating components involved in the six major steps: charging, exposure,
development, transfer, fusing, and cleaning. If there is any irregularity in one of the rotating components, repetitive defects, such as isolated bands or spots, will occur on the output of the printer or copier. To troubleshoot
these types of repetitive defect issues, the repeating interval of these isolated bands or spots is an important clue
to locate the irregular rotating component. In our previous work, we have effectively identified the presence of
isolated large pitch bands in the output from EP printers. In this paper, we describe an algorithm to estimate
the repetitive interval of periodic bands, when the data is corrupted by the presence of aperiodic bands, missing
periodic bands, and noise. We will also illustrate the effectiveness and robustness of our method with example
Laser electrophotographic printers are complex systems with many rotating components that are used to advance
the media, and facilitate the charging, exposure, development, transfer, fusing, and cleaning steps. Irregularities
that are constant along the axial direction of a roller or drum, but which are localized in circumference can give
rise to distinct isolated bands in the output print that are constant in the scan direction, and which may or may
not be observed to repeat at an interval in the process direction that corresponds to the circumference of the
roller or drum that is responsible for the artifact.
In this paper, we describe an image processing and analysis pipeline that can effectively assess the presence
of isolated periodic and aperiodic bands in the output from laser electrophotographic printers. In our paper, we
will discuss in detail the algorithms that comprise the image processing and analysis pipeline, and will illustrate
the efficacy of the pipeline with an example.
Observing and evaluating print defects represents a major challenge in the area of print quality research. Visual
identification and quantification of these print defects becomes a key issue for improving print quality. However,
the page content may confound the visual evaluation of print defects in actual printouts. Our research is focused
on banding in the presence of print content in the context of commercial printing. In this paper, a psychophysical
experiment is described to evaluate the perception of bands in the presence of print content. A number of banding
defects are added by way of simulation to a selected set of commercial print contents to form our set of stimuli.
The participants in the experiment mark these stimuli based on their observations via a graphical user interface
(GUI). Based on the collection of the marked stimuli, we were able to see general consistency among different
participants. Moreover, the results showed that the likelihood of an observer perceiving the banding defect in
a smooth area is much higher than in a high frequency area. Furthermore, our results also indicate that the
luminance of the image may locally affect the visibility of the print defects to some degree.