Multiple channel writing devices are important to the graphics arts industry for applications like imagesetting, color proofing, and direct-to-plate writing. Eastman Kodak Company has developed a novel approach to the design of these devices. The laser array consists of 10 groups of 16 laser diodes, which are combined with diffractive optics into 10 individually addressable writing channels. This design gives us the ability to achieve higher printing power levels, as well as a level of redundancy for commercial use. This paper covers aspects of the structure of the array devices, as well as how they are integrated into working printheads. The major part of the discussion is on the characterization of the arrays and the printheads for spot quality and power levels. It touches on the metrics used to predict print quality by looking at spot quality, and on the equipment used to make these measurements in a timely fashion over many focus positions. Finally, there is a brief discussion of the technology transfer that resulted in a successful transition of this project from R&D into manufacturing.
Suzanne K. Wyatt,
"Integration and characterization of multiple spot laser printheads", Proc. SPIE 3000, Laser Diode and LED Applications III, (10 January 1997); doi: 10.1117/12.263489; https://doi.org/10.1117/12.263489