Abstract: Powdery dry lubricant is applied to the surface of a sliding member to be used with a copying machine, a printer or a facsimile machine operating on the basis of electrophotography, in place of toner particles in order to conduct various tests during the assembling process of those machines. Such dry lubricant is applied to a sliding member such as developing sleeve, developing blade, photosensitive drum or developing agent recovering blade, by 1) charging the dry lubricant contained in a container having an opening with electricity, 2) supplying air to the container to eject the electrically charged dry lubricant from the opening toward the sliding member that is grounded and secured as separate from the opening, and 3) causing the dry lubricant ejected from the opening to be adsorbed by the sliding member by means of electrostatic force.