GENZOZAISOSEIBUTSU

摘要

PURPOSE:To improve a black solid development characteristic and to extend the life of the titled compsn. by using ferrite particles having the characteristics of >=10<9>OMEGAcm electric resistivity in 1kV/cm electric field and <=40emu/g satd. magnetization rate as a carrier and a microtoner having substantially 1-10mum grain size as a toner. CONSTITUTION:The ferrite particles having the characteristics of >=10<9>OMEGAcm electric resistivity in 1kV/cm electric field and <=40emu/g satd. magnetization value and <=30mum average grain size are used as the carrier and the grain size of the toner is made substantially 1-10mum. The reason for specifying the electric resistivity of the ferrite core to >=10<9>OMEGAcm at 1kV/cm electric field intensity is to avert the image change by toner filming which is of a problem when the resistance is low. The grain size of the carrier is the significant factor to determine the density of a magnetic brush and is important as the grain size thereof relates also to the toner replenishing power to embed an electrostatic latent image with the toner. The adequate grain size is substantially 1-10mum in order to exhibit the excellent black solid printing characteristic and to extend the life of an imaging characteristic in particular.