| 摘要 |
PROBLEM TO BE SOLVED: To provide a device and a method for image formation which can stabilize image density in a short time with high precision. SOLUTION: While patch formation conditions (electrostatic charging bias and developing bias) are varied, line patch images are formed one after another and at the same time, the optimum electrostatic charging bias and the optimum developing bias needed to form a toner image of low target density are determined according to the density values of the respective patch images. Here, a developing bias satisfying an equation (|Vb|=|Von|+Vcon) is set so as to form line patch images with respective electrostatic charging biases. Consequently, a toner image of high target density can be formed under any of patch generation conditions (combination of electrostatic charging bias and developing bias) and the image density of a toner image of a high density side can be controlled with high precision. |
