A liquid ejection head includes a support member extending in a first direction, a print element board having an ejection port through which liquid is ejected, and first and second members arranged in the support member adjacent to each other along the first direction, each having a supply path extending in the first direction. The print element board element generates energy used for ejection of the supply paths supplied liquid. The first member includes an outlet port through which the supplied liquid flows out. The second member includes an inlet port through which the liquid from the outlet port flows. The outlet port is provided near a first member supply path end portion on the support member side on which the second member is provided. The inlet port is provided near a second member supply path end portion on the support member side on which the first member is provided.

A liquid ejection head includes a support member extending in a first direction, a print element board having an ejection port through which liquid is ejected, and first and second members arranged in the support member adjacent to each other along the first direction, each having a supply path extending in the first direction. The print element board element generates energy used for ejection of the supply paths supplied liquid. The first member includes an outlet port through which the supplied liquid flows out. The second member includes an inlet port through which the liquid from the outlet port flows. The outlet port is provided near a first member supply path end portion on the support member side on which the second member is provided. The inlet port is provided near a second member supply path end portion on the support member side on which the first member is provided.

A modular inkjet printhead assembly including a plurality of printhead modules mounted on alternating sides of a central rail assembly. The rail assembly includes a beam and a rod attached to a side of the beam. The printhead modules include a jetting module having an array of nozzles, a first alignment tab having a first alignment datum and a second alignment datum, a second alignment tab having a third alignment datum and a fourth alignment datum, a rotational alignment feature including a fifth alignment datum, and a cross-track alignment feature including a sixth alignment datum. Portions of the alignment tabs of the jetting module are adapted to fit within corresponding notches in the beam. Each alignment datum on the printhead modules engage with corresponding alignment features on the rail assembly to position the printhead modules such that the jetting modules are tilted away from the beam.

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 (Pin−PHead) between the 1.sup.st pressure sensor (26) and the 2.sup.nd pressure sensor (56).

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 (Pin−PHead) between the 1.sup.st pressure sensor (26) and the 2.sup.nd pressure sensor (56).

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.in−P.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 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.in−P.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 droplet generator for a continuous stream ink jet printhead includes an elongate cavity for containing ink and nozzle orifices in fluid communication with the cavity for passing the ink from the cavity to form jets. The nozzle orifices extend along a length of the cavity. A mounting plate provides a wall of the cavity opposite the nozzle orifices. A plurality of actuators is disposed in the cavity to vibrate the ink in the cavity such that each jet breaks up into ink droplets at substantially a same predetermined distance from the wall. Each of the plurality of actuators is integrally connected to the mounting plate by a membrane.

A droplet generator for a continuous stream ink jet printhead includes an elongate cavity for containing ink and nozzle orifices in fluid communication with the cavity for passing the ink from the cavity to form jets. The nozzle orifices extend along a length of the cavity. A mounting plate provides a wall of the cavity opposite the nozzle orifices. A plurality of actuators is disposed in the cavity to vibrate the ink in the cavity such that each jet breaks up into ink droplets at substantially a same predetermined distance from the wall. Each of the plurality of actuators is integrally connected to the mounting plate by a membrane.

A liquid discharge head may reduce possibility that pressure from a discharge unit reaches a third channel and a fourth channel. The liquid discharge head includes a plurality of discharge units each including a discharge hole, a pressurization chamber communicating with the discharge hole, a first channel for liquid supply to the pressurization chamber, and a second channel for liquid collection from the pressurization chamber, a pressurizing part configured to pressurize the pressurization chamber, a third channel connected commonly to the first channels of the plurality of discharge units, the third channel for liquid supply to the discharge units, a fourth channel connected commonly to the second channels of the plurality of discharge units, the fourth channel for liquid collection from the discharge units, and a fifth channel connecting the discharge units and having channel resistance larger than channel resistance of the first channel and the second channel.