TONER FOR ELECTROPHOTOGRAPHY

PURPOSE:To shift the fixable temp. region of the toner for electrophotography to a high temp. side without changing the min. temp. by incorporating specific polyalkylene having a specific average particle volume and specific weight average mol. wt. into a binder resin and coloring agent. CONSTITUTION:The average particle volume of the polyalkylene to be incorporated is >=0.05mum and polyethylene having the weight average mol. wt. ranging 1500-6000 or polypropylene having the weight average mol. wt. ranging 3000-6000 is preferable as the polyalkylene. The average particle volume is obtd. by embedding the toner 1 into a suitable binder, slicing the same to about 0.1mum thickness by a diamond cutter, photographing the same with a transmission type electronmicroscope and determining the average max. horizontal length of 10 particles which are large among the polyalkylene particles 4 by an image analysis. This length is assumed to be the diameter of the spherical particle and the volume thereof is determined; further, this volume is averaged with 10 particles of the toner, by which the average particle volume is calculated.