A device for measuring the flow rate and viscosity of ink sent to a print head of an ink jet printer comprises: a restriction of the diameter of a conduit for the flow of ink arranged in the path thereof defined by the conduit; a sensor for measuring the pressure difference (P.sub.in-P.sub.out) between the pressure of fluid upstream of the restriction and the pressure of ink downstream of the restriction; a viscous leak, creating a pressure drop by friction loss, the viscous leak being in series with the restriction, in the path of the ink defined by the conduit; a sensor for measuring the pressure difference (P.sub.inV-P.sub.outV) between the pressure of fluid upstream of the viscous leak and the pressure of ink downstream of the viscous leak; and a circuit for calculating the flow rate and viscosity of ink as a function of: (P.sub.in-P.sub.out and (P.sub.inV-P.sub.outV).

A recording element substrate includes a substrate, a plurality of energy generating elements arranged on the substrate to form an element row, a plurality of supply ports arranged along the element row to form a supply port row, and a plurality of supply paths extending from the plurality of supply ports along the thickness direction of the substrate, wherein a plurality of beam portions disposed between adjacent supply ports in the direction of the supply port row has a plurality of conductor layers in which a conductor layer including a power supply conductor connected to the energy generating elements and a conductor layer including a ground conductor connected to the energy generating elements, are stacked along the thickness direction of the substrate, and wherein at least one of the plurality of conductor layers is occupied by one power supply conductor or one ground conductor.

In order to make it possible to inform as apparatus handler through a simple, means of precautions to take in handling ink of the correct ID number when an inputted ink ID number is correct, this inkjet recording apparatus is provided with a print head having; a nozzle part, an ink container that houses ink supplied to the nozzle part, information reading unit for reading information that distinguishes the type of ink accompanying an ink supply container that supplies ink to the ink container, a determination unit for determining from the read information whether the ink housed in the ink supply container is the correct ink, a storage unit for storing ink-related information in correlation with the ink-type-distinguishing information, a stored-information extraction unit for extracting from the storage unit the ink-related information corresponding to the ink-type-distinguishing information read by the information reading unit when the ink is determined to be correct by the determination unit, and a display unit for displaying the ink-related information extracted toy the stored-information extraction unit on a screen.

A device (20) for measuring the flow rate of ink sent to a print head of an ink jet printer, comprising: a restriction (22) of the diameter of the flow of ink, arranged in the path thereof, sensors (26, 28) for measuring the pressure difference (P.sub.inP.sub.out), between the pressure of fluid upstream of the restriction (P.sub.in) and the pressure of ink downstream of the restriction (P.sub.out).

A device (20) for measuring the flow rate and the viscosity of ink sent to a print head (50) of an ink jet printer, comprising: a conduit (200), for supplying the print head (50), this conduit being provided with a 1.sup.st pressure (Pin) sensor (26) at a first end and a 2.sup.nd pressure (PHead) sensor (56) at a 2.sup.nd end, circuit or controller (26, 56) for measuring at least the pressure (PHead) of the 2.sup.nd pressure sensor (56) and the pressure difference (PinPHead) between the 1.sup.st pressure sensor (26) and the 2.sup.nd pressure sensor (56).

A method for testing at least one nozzle of a multi-jet print head of an inkjet printer including a plurality of nozzles (4), at least one 1.sup.st and one 2.sup.nd deviation electrode (14a, 14b) for each jet, method in which: at least one jet is formed using the nozzle (9), at a drop formation frequency, an estimate is made of:

a cutoff frequency (Fc) of at least this jet, by variation of the jet formation frequency, at a constant jet velocity, or, at constant formation frequency of the drops from at least this jet, by variation of the jet velocity, the velocity at which the cutoff frequency (Fc) is equal to the formation frequency; this cutoff frequency (Fc) or this velocity is compared with a reference value and the functional or non-functional state of at least the nozzle is deduced.

The invention relates to a method for detecting the presence of a jet from a multi-jet print head of an inkjet printer comprising a plurality of nozzles (4), at least one 1.sup.st and one 2nd deviation electrode (14a, 14b) for each jet, in which: the inkjet is produced by one of the nozzles, at a frequency and is then charged by a voltage V.sub.THT at a frequency f.sub.THT, f.sub.THT not being an integer multiple or sub-multiple of f.sub.stim1; a jet charge signal is detected, derived from sampling, at frequency f.sub.stim1, of the voltage at frequency f.sub.THT, at least one spectral component of this signal being used to detect the presence of the jet.

A liquid discharge apparatus includes: a head unit that has a plurality of nozzles that discharge a column-shaped liquid; a liquid droplet generating unit that applies cyclically changing energy to positions of the column-shaped liquids discharged from the plurality of nozzles, respectively, which are separated from the plurality of nozzles, respectively, and that generates liquid droplets; and a direction changing unit that changes a flying direction of at least some liquid droplets of the generated liquid droplets.

A liquid discharge apparatus includes: a head unit that has a plurality of nozzles that discharge a column-shaped liquid; a liquid droplet generating unit that applies cyclically changing energy to positions of the column-shaped liquids discharged from the plurality of nozzles, respectively, which are separated from the plurality of nozzles, respectively, and that generates liquid droplets; and a direction changing unit that changes a flying direction of at least some liquid droplets of the generated liquid droplets.

A liquid discharge apparatus includes: a head unit that has nozzles that discharge a column-shaped liquid; a liquid droplet generating unit that applies cyclically changing energy to positions of the column-shaped liquids discharged from the nozzles, which are separated from the nozzles, and that generates liquid droplets; and a direction changing unit that changes a flying direction of at least some liquid droplets of the generated liquid droplets.