Multiple roll developing apparatus

Claim 1

An improved developing apparatus for applying one-part toner particles to a photoconductive surface in a copy machine, said apparatus comprising A. a plurality of magnetic brushes arranged in a parallel spaced relationship so as to form an elongate nip area at their proximate surface, each of said brushes comprises 1. a magnetic shaft having poles arranged in a spaced relationship so as to form a circular array about said shaft, 2. a thin walled annular-shaped sleeve formed of nonmagnetizable material positioned around and proximate said magnetic shaft, and 3. means for mounting said magnetic shaft and said sleeve of said brush for relative rotational movement, B. means for supplying toner particles to said brushes including means defining a reservior for said toner particles and an adjustably-mounted doctor blade disposed between said reservoir and one of said brushes to control the amount of powder carried by said one of said brushes, and C. drive means affording relative rotation of said magnetic shafts and said sleeves to advance said toner particles from said doctor blade toward said nip area between said brushes so as to divide said toner particles at said nip area and transfer a portion of said toner particles to an adjacent brush and direct said toner particles on said brushes toward said photoconductor.