NEGATIVELY CHARGEABLE TONER FOR ELECTROSTATIC PHOTOGRAPHY

PURPOSE:To enable a toner to have good negative chargeability even at the time of successively copying of a large amount by using a carbon black having an active hydrogen content of 15.0X10 - 30.0X10mol/g in the surface as a colorant. CONSTITUTION:The toner to be used is prepared by mixing a resin, the carbon black having the active hydrogen content of 15.0X10 - 30.0X10mol/g in the surface as the colorant, a dyestuff, and auxiliary additives when needed, sufficiently kneading the mixture in a kneader with heating rolls, then pulveriz ing it, further, when needed, finely pulverized with a jet mill, and classified to form the toner having a particle diameter distribution of 5 - 25mum, thus permitting the obtained toner to be improved in negative chargeability even at the time of a large amount copying.