Patents Examined by Maria Nuzzollo
  • Patent number: 5952138
    Abstract: The invention relates to a magnetic developer comprising a magnetic toner containing at least a binder resin, a magnetic material and a hydrocarbon wax,wherein said magnetic toner has such properties that:a DSC curve of the toner measured by the use of a differential scanning calorimeter is characterized in that with an endothermic peak in raising temperature, its onset temperature is 105.degree. C. or below and its peak temperature is in the range of from 100.degree. C. to 120.degree. C., and that with an exothermic peak in dropping temperature its peak temperature is in the range of from 62.degree. C. to 75.degree. C. and its peak intensity ratio is 5.times.10.sup.-3 or more; andsaid magnetic material has such properties that:a residual magnetization 6r is in the range of from 12 emu/g to 30 emu/g and a coercive force Hc is in the range of from 130 oersteds to 300 oersteds in a magnetic field of 10,000 oersteds.
    Type: Grant
    Filed: March 30, 1995
    Date of Patent: September 14, 1999
    Assignee: Canon Kabushiki Kaisha
    Inventors: Tetsuhito Kuwashima, Satoshi Matsunaga, Yukari Ishibashi