Patent ID: 9665030
Date: 2017-05-30
CPC Classifications: G03G

Claim:
1. An image forming apparatus capable of forming an image on a print medium while feeding the print medium, the image forming apparatus comprising: an image supporting member; a charger provided in proximity to the image supporting member; a power source configured to apply a plurality of charging voltages to the charger sequentially while no print medium is fed, the plurality of alternating voltages having different peak-to-peak voltages for a forward discharge range, in which charge transfer from the charger to the image supporting member occurs, and different peak-to-peak voltages for a reverse discharge range, in which charge transfer from the image supporting member to the charger occurs, respectively; an amperometric detector configured to detect values of alternating current flowing in the charger during application of the plurality of charging voltages; and a processor configured to derive a characteristic line of alternating current value with respect to alternating voltage for the forward discharge range and a characteristic line of alternating current value with respect to alternating voltage for the reverse discharge range from the values of alternating current detected by the amperometric detector, wherein the processor derives a peak-to-peak voltage to be used in an image forming process depending on different ranges of a difference in slope between the characteristic line for the forward discharge range and the characteristic line for the reverse discharge range, and wherein the processor derives the peak-to-peak voltage to be used in the image forming process based on a point of intersection between the characteristic line for the forward discharge range and the characteristic line for the reverse discharge range in a case in which the difference is in a first value range.