Patent ID: 8445651

Claim:
A method for producing charge control agent, the method comprising (a) mixing an azo compound with a salicylic acid chromium complex in an aqueous medium, and adding to said medium an inorganic base and a compound selected from the group consisting of a long-chain alkyl ammonium salt, an aryl ammonium salt, a crown ether and a strong polar solvent to form a mixture, wherein an amount of said long-chain alkyl ammonium salt, said aryl ammonium salt, or said crown ether is between 1 and 30 wt. % based on the amount of said salicylic acid chromium complex, and an amount of said strong polar solvent is between 0.5 and 30 wt. % based on the amount of said salicylic acid chromium complex; and (b) heating the obtained mixture in (a) to obtain an azo chromium complex indicated in formula (1), wherein, R 1 to R 4 are independently selected from the group consisting of hydrogen, substituted or unsubstituted alkyl having 1-18 carbon atoms, alkenyl with 1-18 carbon atoms, alkoxy with 1-18 carbon atoms, sulfonic acid group, methyl sulfonyl, sulfoacid amino, alkyl amino sulfonyl of the alkyl with 1-18 carbon atoms, hydroxyl, carboxyl, —COOR 5 , in which, R 5 is alkyl with 1-18 carbon atoms, acetylamino, bromine, chlorine, iodine, fluorine and nitryl; Z 1 and Z 2 are independently selected from the group consisting of hydrogen, carboxyl, hydroxyl, —COOR 6 , —CONHR 7 , and —NHCOR 8 , in which, R 6 -R 8 are independently substituted or unsubstituted phenyl, substituted or unsubstituted alkyl having 1-18 carbon atoms, or substituted or unsubstituted cycloalkyl having 3-12 carbon atoms; additionally, A m+ is a cation having an oxidation state of +1 to +6; m is an integer between 1 and 6, and n 1 −n 4 are integers between 0 and 4 and are required to meet the condition of n 1 +n 2 =4 and n 3 +n 4 =4.