Patent ID: 9042751
Filing Date: 2015-05-26
Classification: G03G

Abstract:
1. A high voltage power supply, comprising: a developer carrier for carrying a developer on a peripheral surface thereof; an image carrier for carrying an electrostatic latent image on a peripheral surface thereof; a temperature detection unit for detecting a temperature near the developer carrier; a humidity detection unit for detecting a humidity near the developer carrier; a DC power supply part for outputting a direct voltage of a voltage value indicated by a first control signal inputted; an AC power supply part for outputting an alternating voltage of a setting value indicated by a second control signal inputted; a developing control unit for applying a developing bias voltage, which is obtained by superimposing the direct voltage that is outputted from the DC power supply part by outputting the first voltage control signal to the DC power supply part and the alternating voltage that is outputted from the AC power supply part by outputting the second control signal to the AC power supply part, to the developer carrier and generating a potential difference between the developer carrier and the image carrier, and thereby supplying the developer to the image carrier and developing the electrostatic latent image; an initial voltage setting unit for setting initial values of the voltage value and the setting value based on charging characteristics of the developer according to the temperature detected by the temperature detection unit and the humidity detected by the humidity detection unit; a load detection unit for detecting capacitance between the developer carrier and the image carrier; a variation detection unit for setting the capacitance detected by the load detection unit when the initial values were set by the initial voltage setting unit as a reference capacitance, and detecting a variation indicating to what extent the capacitance detected by the load detection unit has changed from the reference capacitance whenever the capacitance is detected by the load detection unit; and a voltage correction unit for executing correction processing of correcting the developing bias voltage by decreasing the voltage value as the variation increases, and increasing the voltage value as the variation decreases whenever the variation is detected by the variation detection unit during a period from the start to the end of an operation of developing the electrostatic latent image by the developing control unit after the initial values were set by the initial voltage setting unit.