Method and apparatus for image forming capable of effectively preventing resonance of frequencies

An image forming apparatus, comprising:

• an image bearing member configured to bear an image;
• means for charging a surface of the image bearing member when a direct current bias voltage added to at least an alternating bias voltage is applied to the means for charging, the means for charging having a frequency fc of the alternating bias voltage;
• and
• means for measuring a potential of the surface of the image bearing member, the means for measuring having a drive frequency fvsen,
• wherein a relationship of the frequency fc and the drive frequency fvsen is expressed as fc≠fvsen×n and fc×n≠fvsen.

A method of image forming, comprising the steps of:

• charging a surface of an image bearing member with a charging member charged with a direct current bias voltage added to at least an alternating bias voltage having a frequency fc;
• and
• measuring a potential of the surface of the image bearing member using a sensor having a drive frequency fvsen,
• wherein a relationship of the frequency fc and the drive frequency fvsen is expressed as fc≠fvsen×n and fc×n≠fvsen.

A process cartridge, comprising:

• an image bearing member configured to bear an image;
• at least one of (a) a charging member configured to charge a surface of the image bearing member when a direct current bias voltage added to at least an alternating bias voltage is applied to the charging member, the charging member having a frequency fc of the alternating bias voltage, (b) a developing member configured to develop the image, and (c) a cleaning member configured to remove toner remaining on the image bearing member;
• and
• a measuring member configured to measure a potential of the surface of the image bearing member, the measuring member having a drive frequency fvsen,
• wherein a relationship of the frequency fc and the drive frequency fvsen is expressed as fc≠fvsen×n and fc×n≠fvsen.

A process cartridge, comprising:

• an image bearing member configured to bear an image;
• at least one of (a) means for charging a surface of the image bearing member when a direct current bias voltage added to at least an alternating bias voltage is applied to the means for charging, the means for charging having a frequency fc of the alternating bias voltage, (b) means for developing the image, and (c) means for removing toner remaining on the image bearing member;
• and
• means for measuring a potential of the surface of the image bearing member, the means for measuring having a drive frequency fvsen,
• wherein a relationship of the frequency fc and the drive frequency fvsen is expressed as fc≠fvsen×n and fc×n≠fvsen.