Apparatus and method for determining a measure for the solid content of a liquid toner, and printing system including such an apparatus

A measurement apparatus for determining a measure for the solid content of a liquid toner, said liquid toner comprising a carrier liquid with marking particles, and said solid content being the ratio of the mass of the marking particles divided by the mass of the liquid toner, said measurement apparatus comprising: a measurement space for receiving liquid toner, said measurement space comprising at least one hydrostatic pressure sensor configured and arranged for measuring data representative for the hydrostatic pressure caused by the liquid toner at at least one predetermined position in the measurement space; a controller configured for receiving the measured data and for determining a measure for the solid content of the liquid toner based on the received data.