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

Claim 6:
7. An image forming device that forms a fogging image on a photoconductor as an image carrier using developer prior to forming a print image, the image forming device comprising:
the image carrier;
a charge device that electrically charges a surface of the image carrier;
a developer device that supplies developer to the image carrier;
an intermediate transfer body that carries the fogging image transferred from the image carrier;
power supply circuitry that applies a charge bias to the charge device and applies a developer bias to the developer device;
a detector that detects the fogging image on the intermediate transfer body;
a non-transitory computer-readable recording medium comprising a program; and
a hardware processor that executes the program to operate as:
a control unit that changes a fogging margin, which is a difference between charge bias and developer bias, in steps, controls the power supply circuitry so that the charge bias and developer bias are set according to the steps, and controls the detector to detect for each step;
a calculation unit that calculates, for each step, an amount of change between a detection value detected by the detector and a detection value detected by the detector for a next step in sequence; and
a determination unit that obtains, for each step, a difference between an amount of change calculated by the calculation unit and an amount of change calculated by the calculation unit for a subsequent step in the sequence, determines 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, determines 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.