| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize that an air flow from the outdoor air is controlled and a pressure in a developing device body is properly maintained by detecting a pressure in the developing device during printing. <P>SOLUTION: The pressure in a device body 5a of a developing device 5 is controlled so as to be between the two reference values by always grasping a pressure condition in the device body 5a by a sensor 25 for detecting the pressure in the device body 5a of the developing device 5 and changing a casing 21 by a stepping motor 26 according to a predetermined changing mode. When the pressure in the developing device 5 is high, the space between the casing caps 22 is widened, and when the pressure in the developing device 5 is sufficiently low, an air flow from the outdoor air is controlled and the pressure in the developing device is properly maintained by narrowing the space between the casing caps 22, thereby preventing scattering of toner. <P>COPYRIGHT: (C)2013,JPO&INPIT |
