Patent ID: 9329524
Filing Date: 2016-05-03
CPC Classification: G01N,G03G

Claim Text:
1. An apparatus for detecting a toner density of a liquid developer, comprising: a liquid developer circulating path for circulating therethrough the liquid developer for an electrophotographic printer stored in a main tank, a liquid developer feeding path for feeding the liquid developer stored in the main tank to a developing machine provided outside the liquid developer circulating path, a deaerator provided in the liquid developer circulating path and a density detector provided downstream of the deaerator in the liquid developer circulating path, wherein said deaerator has one bundle or a plurality of bundles of hollow fibers, each of the hollow fibers being formed of a bundle of hollow fiber membranes, wherein the inside of the hollow fiber membrane is depressurized and the liquid developer is configured to flow under pressure over the outer peripheral surface of the hollow fiber membrane, whereby air dissolved in the liquid developer is forced to permeate the hollow fiber membrane into said inside of the hollow fiber membrane, and said density detector comprises the density detector detects the toner density of the liquid developer flowing in the flow passage due to the propagation velocity of ultrasonic waves that propagate through the liquid developer changing with a change in toner density of the liquid developer.