Patent ID: 11874611
Assignee: KONICA MINOLTA, INC.
Field: Optics (Instruments)
Classification: CPC G | IPC G

Claim 7:
8. A fogging margin determination method used in an image forming device that forms a fogging image prior to forming a print image, comprising an image carrier, a charge device that electrically charges a surface of the image carrier, a developer device that supplies developer to the image carrier, and power supply circuitry that applies a charge bias to the charge device and applies a developer bias to the developer device, the fogging margin determination method comprising:
detecting the fogging image formed on the image carrier;
changing a fogging margin, which is a difference between charge bias and developer bias, in steps, controlling the power supply circuitry so that the charge bias and developer bias are set according to the steps, and controlling the detector to detect for each step;
calculating, for each step, an amount of change between a detection value detected and a detection value detected for a next step in sequence;
obtaining, for each step, a difference between an amount of change calculated and an amount of change calculated for a subsequent step in the sequence, determining whether or not each obtained difference is greater than or equal to a defined value, and upon obtaining a first fogging margin range of at least one difference greater than or equal to the defined value and a second fogging margin range of at least one difference less than the defined value, determining a position of a boundary between the first range and the second range as a fogging margin to be used in forming the print image.