IMAGE FORMING APPARATUS

PROBLEM TO BE SOLVED: To prevent a trace of transfer discharge abnormality, which possibly occurs in constant-current control, especially, in low-temperature and low-humidity environment, from causing an image to have unevenness, white spots, etc., while suppressing the cost. SOLUTION: A specified value of one standard which does not depend upon imaging conditions is so set that a maximum value of a transfer voltage is controlled to the specified value in a state wherein resistance variation of the whole system of an image forming apparatus becomes maximum, for example, only in low-temperature and low-humidity environment (S1), and the constant-current control is performed by controlling the maximum value of the transfer voltage by using the specified value so that the specified value is not exceeded (Y at S7). Consequently, a transfer deficiency can be prevented in a high-temperature and high-humidity state and an abnormal image can be prevented from being formed owing to excessive transfer voltage application in a low-temperature and low-humidity environment state without increasing the cost. COPYRIGHT: (C)2005,JPO&NCIPI