Abstract: A double coated pressure sensitive adhesive sheet used for fixing a part of an electronic device including an adhesive layer. At least one of the adhesive layers of the double coated pressure sensitive adhesive sheet has a maximum of loss tangent in a frequency region equal to or larger than a maximum characteristic frequency generated by a shock when the electronic device falls. The maximum of the loss tangent is equal to or greater than 1.

Abstract: On the surface of a developing roller disposed closely to a photosensitive drum, a toner supplied from a toner container to the surface is spread into a thin layer by a toner distribution and charging blade. The triboelectric charge, q.sub.1, of the toner and the triboelectric charge, q.sub.2, of the surface of the toner distribution and charging blade are equalized in polarity and made to satisfy a relation, .vertline.q.sub.2 .vertline.<.vertline.q.sub.1 .vertline.. The triboelectric charge, q.sub.3, of the surface of the developing roller is made to satisfy a relation, -4.0.ltoreq.q.sub.1 /q.sub.3 .ltoreq.-1.2. The triboelectric charge of the toner, q.sub.1, and the triboelectric charge, q.sub.4, of the surface of a recovery blade for recovering the residue of toner adhering to the developing roller are equalized in polarity and, at the same time, made to satisfy a relation, .vertline.q.sub.4 .vertline.<.vertline.q.sub.1 .vertline..