SHEET FEEDER AND IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To provide a high reliability sheet feeder minimizing charge pitch and, in various types of sheets, surely feeding from a bundle of sheets stacked on a sheet stacking member one by one at a high speed, and stably with respect to environmental variation and time variation; and to provide an image forming apparatus with the sheet feeder.SOLUTION: A charging blade 33 includes a front end portion 33a contacting with an endless belt 32 and forming a nip portion together with the endless belt 32; and a microgap G for applying charge onto the surface of a surface layer 32a of the endless belt 32 by performing electric discharge between the charging blade 33 and the endless belt 32. A basic charging width H comprising a nip width N and the microgap G is smaller than a half width of a period (P) of alternating charge applied from the charging blade 33 to the endless belt 32, to be smaller than a charging width W of identical polarity charged in a direction in which the endless belt 32 circulatingly moves.