A-B DIBLOCK COPOLYMER AS ELECTRIC CHARGE CONTROL AGENT FOR NEGATIVE ELECTROSTATIC LIQUID DEVELOPER

摘要

PURPOSE: To obtain a negative working electrostatic liq. developer improving resolution and solid area covering property and capable of preventing the smearing of an image by incorporating a nonpolar liq. dispersive medium, thermoplastic resin particles and an A-B diblock copolymer as an electric charge controlling agent. CONSTITUTION: This liq. developer consists of a nonpolar liq. having a kauri- butanol value of =30, thermoplastic resin particles having =10m area average particle size and an A-B diblock copolymer as an electric charge controlling agent. The blocks B of the copolymer are made of a polymer having a number average mol.wt. of about 2,000-50,000 and practically soluble in the nonpolar liq. The blocks A are made of a quaternized trialkylamino polymer having a number average mol.wt. of about 200-10, 000. The ratio between the number average degree of polymn. of the blocks B and that of the blocks A is 10:2 to 100:20.