Patent ID: 7444093

Claim:
A liquid toner concentration detecting device comprising: a first container, operable to accommodate a liquid toner, and provided with a window; a reflector, disposed in the first container; a light emitter, operable to emit light to the reflector through the window and the liquid toner; a light receiver, operable to receive the light reflected by the reflector through the liquid and the window; and a detector, operable to detect a concentration of the liquid toner based on the light received by the light receiver, wherein the first container is communicated with a development device, which has a second container adapted to accommodate the liquid toner and a developer causing the liquid toner to adhere onto an image carrier to develop an electrostatic latent image formed on the image carrier as a toner image, the first container is identical with the second container, a supply roller is formed with a groove adapted to accommodate the liquid toner and is operable to supply the liquid toner to the developer, and a part of the supply roller, not having the groove, serves as the reflector.