| 摘要 |
PURPOSE:To uniform image density, specially, right-left density difference by adjusting independently potentials applied to electrodes at both ends of a sleeve so that optional potential difference is generated between both ends of a conductive developing roller. CONSTITUTION:When a changeover switch 20 is as shown in a figure, a circuit is formed extending from a high voltage variable power source 19 to an electrode 8E, a sleeve end 15, a resistance 17 (sleeve), a sleeve end 16, and electrode 8A, a variable resistance 18, and then an earth point successively. Therefore, when a voltage V1 is outputted from the power source 19, a voltage drop is caused at one sleeve end 16 by a current flowing through the sleeve and the voltage at the end part 16 becomes V1R2/(R1+R2). Thus, a potential with an optional level and an optional gradient, i.e. optional developing bias is obtained by varying the output V1 of the variable power source 19 and variable resistance R2 or reversing the right and left potentials of the resistance 17 (sleeve) through the operation of the switch 20, so the density of the whole image and the right- left density difference are adjustable. |
