CARBON BLACK MASTERBATCH FOR TONER, TONER FOR DEVELOPING ELECTROSTATIC CHARGE IMAGE USING THE SAME AND PRODUCTION OF THE TONER

摘要

PROBLEM TO BE SOLVED: To allow carbon black in a toner to exist stably in a finely and uniformly dispersed state by using a carbon black masterbatch contg. a specified polyester resin as a base and having specified spectral characteristics at the time of producing the toner. SOLUTION: A dispersible resin based on a polyester resin contg. ethoxylated etherified diphenol as an alcohol component and a polycarboxylic acid having >=3 COOH groups as an acid component is premixed with carbon black, melted and kneaded. The resultant carbon black masterbatch is dissolved in xylene and the spectrum of transmitted light is measured. When absorbance at 450 nm wavelength in the spectrum and absorbance at 800 nm wavelength are represented by (a) and (b), respectively, in the case where the concn. of the carbon black in the xylene is expressed by 1 g/l, the masterbatch has spectral characteristics satisfying the condition of 3