| 摘要 |
<p>An improved liquid developing machine is provided with a controller for controlling concentration of a liquid developer. The machine includes a developing container (12), a tank (14) connected to the developing container through a liquid developer circulating pipe (17,24) and serving to store the liquid developer (14a), a vacuum pump (13) disposed at the outlet side of the developing container (12) for circulating the liquid developer between the developing container and the tank, a concentrated toner container (15), a toner supply pipe (22) for supplying a concentrated toner liquid to the tank (14), and a valve device (16) for opening and closing the toner supply pipe (22) which has one end connected to the developer circulating pipe (24) between the developing container (12) and the vacuum pump (13) so that the concentrated toner liquid is supplementarily supplied to the tank (14) containing the liquid developer under the action of negative pressure produced by the vacuum pump. The valve device (16) cooperates with a concentration detector (18) for detecting concentration of the liquid developer and a concentration control circuit (26b) to constitute the concentration controller which responds to the output signal of the concentration detector (18) for opening or closing the valve (16). The output signal of the concentration detector (18) is periodically sampled at a predetermined time interval to actuate correspondingly the valve. A liquid developer stagnating portion is formed in the pipe (17) so as to maintain the sensor portion of the concentration detector (18) in a wetted state.</p> |
