Process for producing a charge control agent

A process for producing a charge control agent comprising an azo-based iron complex salt compound as an effective component, comprising:

• (A) obtaining a monoazo compound represented by the following general formula (1) through diazotization coupling:
• wherein,
• p is an integer of 0 to 4 indicative of the number of R1 group(s),
• q and s are each an integer of 0 to 5 indicative of the numbers of R2 group(s) and R3 group(s), respectively, and
• R1 to R3 are each a deuterium atom, halogen atom, nitro group, hydroxyl group, alkyl group, alkenyl group, alkyloxy group, sulfonalkyl group, alkylsulfonate group, sulfonate group, carboxyl group, carboxyester group, sulfonamide group, acetylamino group, benzoylamino group, aromatic hydrocarbon group or aromatic heterocyclic group, with the proviso that when a plurality of R1 groups, R2 groups or R3 groups are existent, said R1 groups, said R2 groups or said R3 groups may be different from one another;
• and
• (B) ironizing the monoazo compound in a solvent while pH is kept at 7.0 to 8.0 and the temperature is maintained at 60±10° C., to produce an azo-based iron complex salt compound represented by the following general formula
• (2):
• wherein, p, q, s and R1 to R3 are as defined in the above general formula (1), and A+ is a cation;
• wherein said azo-based iron complex has an average particle diameter of not more than 4 μm.