Abstract: A charge controller for a toner, containing a polymer of an ethylenically unsaturated monomer, where the polymer has a dielectric loss tangent (tan .delta.) at 100 kHz of 0.008 to 0.3 and a water absorbency of at most 10% by weight, and selected from the group consisting of:(1) a polymer (A1) having units resulting from a monomer (1) having an aromatic ring substituted with at least one electron-attracting group (X) selected from the group consisting of halogen, a nitro group and a cyano group; and(2) a copolymer (A2) of a monomer (2) having an organic acid group or salt thereof, with one or more copolymerizable monomers,a toner binder and toner containing the same are provided which give excellent properties with respect to electrostatic charge amount, charging rate and environmental stability, as well as providing an essentially colorless charge controller containing no metal and improved dispersing properties and transparency.

Abstract: A charge controller for an electrophotographic toner is disclosed which comprises a graft or block copolymer comprising:(a) a polymer moiety having an alkyl group containing 6-50 carbon atoms and a carboxyl group, said moiety being selected from the group consisting of: a moiety of a polymer or a copolymer containing at least 5 mol. % of monomer units of a monoalkyl ester of an .alpha.,.beta.-ethylenically unsaturated dicarboxylic acid, containing 6-50 carbon atoms in the alkyl group; and a moiety of a copolymer containing 5-75 mol. % of monomer units of a carboxylic group-containing .alpha.,.beta.-ethylenically unsaturated monomer, and 6-80 mol. % of monomer units of an ethylenically unsaturated monomer having an alkyl group containing 6-50 carbon atoms; and(b) a polymer moiety, bound graft-wise or block-wise thereto, said moiety (b) being selected from the group consisting of a styrenic polymer moiety, and a polyester moiety.