Mn FERRITE PARTICLE AND DEVELOPER CARRIER FOR ELECTROPHOTOGRAPHY USING THE SAME, DEVELOPER FOR ELECTROPHOTOGRAPHY

摘要

PROBLEM TO BE SOLVED: To provide a Mn ferrite particle having high chargeability and desired magnetic properties.SOLUTION: The Mn ferrite particle having a spinel crystal structure has 0.385 or more of a parameter u showing the position of an oxygen atom in the spinel crystal structure by the Rietveld analysis of an X diffraction pattern. A crystallite diameter is preferably 500Åor more from the viewpoint of further improving chargeability and suppressing a deterioration in magnetic properties. From the viewpoint of further improving chargeability, a metal element of at least one kind selected from a group consisting of Mg, Ca, Ti, Cu, Zn, Sr and Ni is preferably contained in the total amount of 0.5 wt% or more.