Patent ID: 7643766
Filing Date: 2010-01-05
Classification: G01N,G03G

Abstract:
1. A toner concentration measuring device for a liquid developer, comprising: a light-emitting portion having a light-emitting member and a light emergence surface from which light from the light-emitting member emerges; and a light-receiving portion having a light incidence surface through which the light from the light-emitting member enters and a light-receiving member that detects the light entering through the light incidence surface, wherein the light emergence surface and the light incidence surface can make relative movement between a measurement position in which the light emergence surface and the light incidence surface make contact with each other and a waiting position in which the light emergence surface and the light incidence surface are away from each other, the light emergence surface and the light incidence surface make contact with each other at a contact point or along a contact line in the measurement position.