发明名称 |
Image forming apparatus |
摘要 |
An image forming apparatus includes a power source and a controller. A time-averaged value (Vave) of a voltage output from the power source has a polarity in a transfer direction, and an absolute value of Vave is greater than a midpoint value (Voff) of the voltage intermediate between a maximum value and a minimum value of the voltage. With an increase in a difference (Vpp) between the maximum value and the minimum value of the voltage, the controller controls the power source to increase a duty ratio (Duty) expressed by A/(A+B), where A is an application time in one cycle at a return direction side opposite a transfer direction side relative to Voff and B is an application time at the transfer direction side relative to Voff, and with a decrease in (Vpp), the controller controls the power source to reduce Duty. |
申请公布号 |
US9256168(B2) |
申请公布日期 |
2016.02.09 |
申请号 |
US201514594531 |
申请日期 |
2015.01.12 |
申请人 |
Ricoh Company, Ltd. |
发明人 |
Tanaka Shinya |
分类号 |
G03G15/16;G03G21/20 |
主分类号 |
G03G15/16 |
代理机构 |
Oblon, McClelland, Maier & Neustadt, L.L.P |
代理人 |
Oblon, McClelland, Maier & Neustadt, L.L.P |
主权项 |
1. An image forming apparatus, comprising:
an image bearer to bear a toner image on a surface thereof; a transfer device to contact the image bearer to form a transfer nip; a power source to output a voltage to transfer the toner image from the image bearer onto a recording medium interposed in the transfer nip, the voltage including a first voltage in a transfer direction in which the toner image is transferred from the image bearer to the recording medium and a second voltage having a polarity opposite that of the first voltage, and the first voltage and the second voltage alternating upon transfer of the toner image from the image bearer to the recording medium; and a controller operatively connected to the power source to control the power source; wherein a time-averaged value (Vave) of the voltage has a polarity in the transfer direction, and an absolute value of the time-averaged value (Vave) is greater than a midpoint value (Voff) of the voltage intermediate between a maximum value and a minimum value of the voltage, wherein with an increase in a difference (Vpp) between the maximum value and the minimum value of the voltage, the controller controls the power source to increase a duty ratio (Duty) expressed by B/(A+B), where B is an application time in one cycle at a return direction side opposite a transfer direction side relative to the midpoint value (Voff) and A is an application time at the transfer direction side relative to the midpoint value (Voff), and with a decrease in the difference (Vpp), the controller controls the power source to reduce the duty ratio (Duty). |
地址 |
Tokyo JP |