| 摘要 |
PURPOSE:To form a positively chargeable toner which is almost independent of the ratio between the toner and a carrier and a change in the total amount of a developer by using a positively chargeable resin and a positive charge controller. CONSTITUTION:Any known resin contg. groups such as amino, glycidoxy or mercapto can be used as a positively chargeable resin, yet when the easy control of fixability and thermal blocking resistance is taken into consideration, a styrene-acrylic-aminoacrylic copolymer is preferably used. A compound represented by formula I (where each of R1-R4 is 1-8C satd. or unsatd. hydrocarbon, and each of R2-R4 may be H or aromatic hydrocarbon) is used as the aminoacrylic component. The positive chargeability of the copolymer is hardly affected by the ratio of styrene/acrylic monomer, yet when durability and fixability necessary for a toner are taken into consideration, the desired ratio is 50/50- 99/1. The extent of positive charge depends essentially on the ratio of styrene- acrylic monomer/aminoacrylic monomer, so the ratio is required to be decided while taking conditions during development, the composition of the toner and the kind of a magnetic carrier into consideration. The desired ratio is 80/20- 99.5/0.5 in general. |
