Abstract: An apparatus in which developer material is transported to a latent image so as to be deposited thereon to form a powder image thereof. The apparatus includes a mixer disposed interiorly of the transport, for mixing the developer material.

Abstract: A specular reflectance microdensitometer including an illuminating microscope and a collecting microscope, disposed on optical axes at equal and opposite angles relative to a reflecting test surface. The illuminating microscope illuminates a known area on the test surface from which light is reflected into the collecting microscope. The objective lens of the collecting microscope images the illuminated test surface on a field lens which in turn images the objective lens on the face of a fiber optic bundle. The light incident on the fiber bundle is transmitted to a photomultiplier tube for quantitative determination of light level.The amount of light specularly reflected by the test surface is correlated to the density of particle coverage on the surface, and plotted on an X-Y record.