| 摘要 |
PURPOSE:To enable a toner image to be transferred to a plain paper without weakening toner charge, by using a one-component type magnetic toner of particle diameter in a specified range, forming conductive paths between a developing sleeve and a photoreceptor, and injecting charge reverse in polarity to an electrostatic latent image to the toner. CONSTITUTION:A magnetic material having 0.5-5mum average particle diameter amounting to 30-70wt% of the total raw material of a toner containing a binder resin is heat-melted and cooled, then pulverized to give a one-component type toner having 8-18mum average particle diameter and 1.8-2.2 true specific density. Obtained toner particle T have magnetic grains larger than conventional ones, and forms a conductive path in the direction X-X, but toner particle T functions as an insulating material in the direction Y-Y due to larger spaces between magnetic grains 11. As a result, a few toner particles form a conductive path between photoreceptor 2 and grounded developing sleeve 6 surrounding fixed magnets 9, and toner T1 is given positive charge reverse to electrostatic negative charge on photoreceptor 2, thus permitting toner T1 to form a visible image by toner T2 and then, toner T2 to form a transferred toner image of toner T3 by applying an electric field to transfer paper S from the backside. |
