Method for inspecting quality of core material for electrophotographic ferrite carrier

• US 7,880,483 B2
• Filed: 03/28/2008
• Issued: 02/01/2011
• Est. Priority Date: 03/30/2007
• Status: Expired due to Fees

• Current Assignee: Powdertech Co., Ltd.
• Original Assignee: Powdertech Co., Ltd.
• Inventors: Kobayashi, Hiromichi, Aga, Koji
• Primary Examiner(s): Koval; Melissa J
• Assistant Examiner(s): Baldridge; Benjamin M
• Application Number:
  US12/057,530
• Publication Number:
  US 20080238450A1
• Time in Patent Office: 1,040 Days
• Field of Search: 324/693
• US Class Current: 324/693
• CPC Class Codes: G01N 27/026 Dielectric impedance spectroscopy electrochemical impedance spectroscopy for measuring corrosion G01N17/02

Abstract

An object of the present invention is to provide a quality inspection method for obtaining a specifying factor which can more reliably indicate powder characteristics of a core material for an electrophotographic ferrite carrier. The method includes measuring an impedance of the core material for the electrophotographic ferrite carrier to obtain a Cole-Cole plot in which a real number impedance is arranged in an X-axis and an imaginary number impedance is arranged in a Y-axis, and evaluating characteristics of particles of the core material for the electrophotographic ferrite carrier using the Cole-Cole plot.

Claims

1. A method for inspecting a quality of a core material for an electrophotographic ferrite carrier, comprising:

measuring electrical impedances of the core material for the electrophotographic ferrite carrier in a frequency range to obtain a Cole-Cole plot in which a real part of each measured impedance is arranged in an X-axis and an imaginary part of each measured impedance is arranged in a Y-axis; and

evaluating an average surface shape of particles of the core material for the electrophotographic ferrite carrier using the Cole-Cole plot and an equivalent circuit model to which the measured impedances are applied.

2. The method for inspecting a quality of a core material for the electrophotographic ferrite carrier according to claim 1, wherein the Cole-Cole plot is obtained by changing the frequency of a current applied in the impedance measurement in a frequency range of 0.01 Hz to 1 MHz.

3. The method for inspecting a quality of a core material for the electrophotographic ferrite carrier according to claim 1, wherein a state of the particles of the core material for the electrophotographic ferrite carrier is evaluated by using a parameter obtained from the Cole-Cole plot.

4. The method for inspecting a quality of a core material for the electrophotographic ferrite carrier according to claim 1, wherein the quality of the core material for the electrophotographic ferrite carrier is judged by fitting an equivalent circuit model to the Cole-Cole plot and evaluating the quality of the core material based on parameters of the equivalent circuit model, the parameters including a parameter for evaluating a state of the particles of the core material for the electrophotographic ferrite carrier.

5. The method for inspecting a quality of a core material for the electrophotographic ferrite carrier according to claim 1, wherein the quality of the core material for the electrophotographic ferrite carrier is judged by using a relationship between a time constant T₁ which indicates a state of the particles and a time constant T₂ which indicates a state of a powder comprising the particles, the time constants T₁ and T₂ being obtained from the Cole-Cole plot.

6. A method for inspecting a quality of a core material of an electrophotographic ferrite carrier, comprising:

performing electrical impedance measurements of the core material in a frequency range to obtain measurement data;

determining parameters of an equivalent circuit model by fitting the equivalent circuit model to the measurement data; and

evaluating the quality of the core material based on the determined parameters, wherein one of the parameters of the equivalent circuit model is correlated with a specific surface area of particles of the core material, and at least one of the parameters of the equivalent circuit model is correlated with a volume median diameter of particles of the core material.