Abstract: Determining the quantity of an electrically conductive product contained in a reservoir made of electrically insulating material having at least one storage cavity. A resonant circuit is formed, including a capacitive arrangement formed at least part from the reservoir. A measurement procedure is defined according to which a plurality of excitation signals are applied to the resonant circuit having different frequencies, and a plurality of measurement signals are made. A processing procedure is defined which identifies the instantaneous resonant frequency of the resonant circuit, measures the width, for a given amplitude level, of the resonance peak, and derives therefrom an item of information representing the quantity of product contained in the storage cavity. At least one determination cycle is effected, consisting of triggering the measurement procedure and the processing procedure, and capturing the instantaneous value of the item of information.

Abstract: For determining the quantity of an electrically conductive product contained in a reservoir made of electrically insulating material, having at least one storage cavity: a resonant circuit is formed, including a capacitive arrangement comprising at least part of this reservoir; a processing procedure is defined, consisting of identifying, from a plurality of signals corresponding to different frequencies, the value of a characteristic of this resonant circuit, deriving from this value of the characteristic a measurement of the resistance constituted by the product contained in the reservoir in the said capacitive arrangement and deriving therefrom the instantaneous value of an item of information representing the quantity of product contained in the reservoir from a pre-established correlation law; and a least one determination cycle is effected, consisting of triggering the measurement procedure and the processing procedure, and capturing the instantaneous value of the said item of information.

Abstract: Determination of the quantity of consumable product, notably of ink, remaining in a reservoir. A capacitor (36) is formed on each side of the reservoir (24) and a resonant circuit including this capacitor is formed with a circuit forming a notional inductor (74), such as a gyrator, and another capacitor (68), the capacitor (36) being integrated into the circuit forming a notional inductor.

Abstract: In order to monitor the consumption of a normally electrically conductive product contained in a storage chamber of a reservoir made of electrically non-conductive material, the storage chamber is disposed in a capacitive arrangement and a measurement procedure is defined, according to which, in response to an excitation signal applied to the capacitive arrangement, a measurement signal is obtained (at 122), one characteristic of which has an amplitude which varies substantially with the quantity of product contained in the storage chamber. Before deducing the value of information representing the quantity of product available in the reservoir from this amplitude, the measurement signal has filtering applied to it, according to which it is multiplied by a reference signal of frequency at least approximately equal to that of the excitation signal (at 121) and the multiplied signal is applied to a low-pass filter.

Abstract: The object of the invention is the detection of a given threshold (optionally zero) for filling, with an electrically conductive product, a reservoir made of electrically insulating material having a storage cavity connected to an outlet channel. An excitation signal is applied to the cavity, in periodic square waves, and a measurement signal is taken off, one characteristic of which varies substantially with the quantity of product contained in the cavity reaches the filling threshold. From this characteristic, by comparison with a reference threshold, a binary signal C,C′ is derived, which is filtered digitally whilst multiplying it (convolution product) by a signal which is identical to it, but with a delay equal to a multiple, at least equal to one, of the period of the square waves.

Abstract: In order to monitor the state of a reservoir made of electrically insulating material containing a normally electrically conductive product, ink for example, the free end of the outlet channel of the reservoir is connected to a predetermined potential and two measurement procedures are defined, the first of which results in a first measurement signal, a characteristic of which varies mainly with the quantity of product contained in the storage cavity of the reservoir, and the second of which results in a second measurement signal, a characteristic of which varies mainly with the electrical conductivity of the channel between its ends.During the measurements, an abnormality correction procedure (or a simple alarm procedure) is triggered when the characteristic of the second measurement signal indicates a low electrical conductivity of the channel (absence of product) whilst the characteristic of the first signal indicates that there is still product in the storage cavity.