In Liquid electro photography (LEP), deformable blades are used to remove ink residuals and liquid from the Organic Photoconductor (OPC) drum. The thin layer remaining after the blade can produce undesirable chemical residuals on its surface. When bombarded by ions at the charging station, this layer can oxidize and affect the OPC's electrical properties. In this work we investigate the blade-OPC drum conjunction under fully flooded inlet and outlet conditions; a theoretical model incorporating elastohydrodynamic (EHD) considerations was developed where a deformable blade is deflected by a moving surface (OPC). Unlike typical EHD problems which are widely discussed in the literature, our case consists of a contact line which causes singularity problem in the analysis. This singularity is due to the blade's sharp corner edge prior to its deformation. In order to overcome this singularity, we first solved the elastic-static deformation of the tip using finite element simulation (COMSOL) and combined hydrodynamics considerations afterwards. Experimental results were found with good agreement to our calculations. We found that for a 2 [mm] width blade (1.2 [mm] deflection), the film thickness remaining after the OPC surface wiping is about 25 [nm]. The contact nip length is 12 [μm], where the maximum conjunction pressure was found to be 4 [MPa] and 1.8 [MPa] under static and elastohydrodynamic conditions, respectively.
Wael Salalha, Doron Avramov, "Elastohydrodynamic Study of Deformable Blade-Organic Photoconductor Conjunction" in Proc. IS&T Int'l Conf. on Digital Printing Technologies and Digital Fabrication (NIP25), 2009, pp 220 - 224, https://doi.org/10.2352/ISSN.2169-4451.2009.25.1.art00062_1