Method of forming monochromatic or dichromatic copy images

DETAILED DESCRIPTION The main object of the present invention is to provide a method of forming monochromatic or dichromatic copy images with ease.
Another object of the invention is to provide an image forming method adapted to produce satisfactory monochromatic or dichromatic copies with use of a simple arrangement under conditions which are settable very easily.
Another object of the invention is to provide an image forming method by which a composite latent electrostatic image formed by two exposures can be satisfactorily developed by a single developing unit to give a distinct copy image free of fog.
Still another object of the invention is to provide an image forming method in which a latent electrostatic image formed from a dichromatic original can be satisfactorily developed in two colors by a single developing unit to give a distinct copy free of fog.
These and other objects of the present invention can be fulfilled by an image forming method comprising the steps of forming a latent electrostatic image having at least three different potential levels on a photosensitive member, and developing the latent electrostatic image with a developer to obtain a monochromatic or dichromatic copy image, the developer being composed of at least two components of a nonmagnetic insulating toner and a high-resistivity magnetic carrier triboelectrically chargeable with the toner and having a high resistivity of at least 10.
sup.
12 ohm-cm, the carrier being in the form of particles about 5 to about 40 microns in size, prepared by dispersing a magnetic fine powder in an insulating resin and containing the magnetic fine powder in a proportion of 50 to 75% by weight.