| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a magnetic toner having high environmental stability and degradation resistance, in particular, to suppress a ghost image that generates in a first print out process after the toner is left to stand under high temperature and high humidity conditions and then used for a long period of time, and to stabilize density in long-term use and fog. <P>SOLUTION: The magnetic toner comprises magnetic toner particles containing a binder resin and a magnetic material, and an inorganic fine powder. In an observation on a cross section of the magnetic toner by use of a transmission electron microscope (TEM), 75% by number or more of magnetic materials included in each magnetic toner are present from the surface of the magnetic toner to a depth corresponding to 0.15 time of a circle equivalent diameter C of the projected area. The relation between an absorbance A1 at a wavelength of 338 nm of a supernatant when the magnetic toner is immersed in hydrochloric acid, and an absorbance A2 at a wavelength of 338 nm of a supernatant when a sample prepared by press-forming the magnetic toner into a pellet is immersed in hydrochloric acid, satisfy the following formula (1): A2/A1≤2.5×10<SP POS="POST">-2</SP>. <P>COPYRIGHT: (C)2012,JPO&INPIT |
