2016 Volume 24 Issue 4 Pages 43-51
Virtual design has often been employed in past usability evaluations; results obtained by applying virtual design to a mechanical design are reported here. Virtual design was applied to the conceptual design of a dust shutter provided in a multifunction electrophotographic printer to improve the immunity of its image density sensor to fouling. Four evaluators, of whom three were well acquainted with the subject and one was not, made a sensory evaluation of the fouling of the sensor surface on a seven-grade scale in which fouling was treated as a smaller-is-better characteristic, and the proposed conceptual design was evaluated with respect to two types of fouling having different causes, derived from field reports of existing printers. The factor effects obtained as a result differed from one evaluator to another, but reproducibility was obtained for substantially all of them. On the basis of this all four evaluators conducted a design review, and were able to select the best proposed design on the basis of concrete, quantitative information, specifically, a factor effect diagram. An improvement effect was also obtained in a confirmation test carried out on an actual printer. During the process, information and findings that appear useful for the future development of virtual design were obtained, such as the zoned grading method, selection of a proposed design through consultation, and the treatment of knowledge.
