DMD and laser exposure modules are compared with respect to the formation of a single pixel on the photoconductor. Toner development is assumed to neutralize the normal component of the electric field above the photoconductor at the location of the toner about to be developed. This field is produced by bias voltages, the single pixel latent image, and toner already developed. Care is taken in predicting development of the second layer of toner to assume that the latent image is on the surface of the photoconductor and the first layer of toner is above the surface of the photoconductor. The predicted toner development is in accord with the experimental data. The analysis shows that the normal component of the electric field for single pixel development produced by a 600 dpi DMD exposure module is stronger than the corresponding field of an 85 μm wide Gaussian pixel produced by a laser exposure module. Therefore, toner development resulting from the DMD exposure module is more stable, smaller, and more compact on the photoconductor than the toner developed image produced by the corresponding laser exposure module. Comparing theory with experimental data where the exposure of the photoconductor by the DMD exposure module is varied, suggests that toner development only begins after a threshold electric field is reached. Justification for a threshold behavior is given.
John B. Allen, Albert B. S. Coit, "Comparison of the Single Pixel Development of DMD (Digital Micromirror Device) and Laser Exposure Modules in Electrophotographic Printing" in Journal of Imaging Science and Technology, 1999, pp 309 - 319, https://doi.org/10.2352/J.ImagingSci.Technol.1999.43.4.art00001