METHOD AND INSTRUMENT FOR MEASURING QUANTITY OF ELECTROSTATIC CHARGING OF TONER PARTICLE

摘要

PURPOSE:To speedily measure the quantity of electrostatic charging of individual toner particles with high accuracy by moving up and down toner particles and then holding them stationary by varying an electric field. CONSTITUTION:Compressed air is sent in a toner reservoir 24 from an air pump intermittently and then toner particles T are blown up and electrified by friction. The toner particles are light, so when valves 25 and 26 are open, they are guided into a container 12 in a cloud. When the toner particles strike on the internal wall surface 12a, which is positively electrified because the internal wall surface 12a is made of glass and the toner particles are made of polystyrene. The toner particles T- which are electrified negatively are therefore attracted to and held on the internal wall surface 12a and the toner particles T+ which are electrified positively fall individually and are sent in an electric field measurement chamber 10. Then a voltage while measured by a voltmeter 16 is adjusted through a variable power source 11 to move up and down and hold the charged toner particles stationary in the electric field measurement chamber 10, and an image analyzing device measures the speed of the toner particles. The radius (r) of the particles and the quantity Q of electrostatic charging are calculated from specific expressions based on the data.