Abstract: An apparatus for optimizing vibration attenuation of a printed circuit board (PCB) by means of a tunable control for adjusting the volumetric storage capacity, effective mass and travel displacement of a particle impact damper (PID). The apparatus is comprised of a housing with a single or plurality of sealed storage tank(s) containing a payload of tungsten balls (or other materials) with a single or plurality of adjustment screw(s). The volumetric capacity of the storage tank is at maximum when the screw is fully withdrawn from apparatus. The volumetric capacity of the apparatus is reduced when the screw is inserted into the storage tank. The tunable adjustment screw controls the performance of the PID to dampen and attenuate (reduce) the vibration in a printed circuit board without the need to add or remove the payload of tungsten balls inside the particle impact damper.

Abstract: A magnetorheological fluid-based device and method may include the use of magnetorheological (MR) fluid, a primary magnetic field to control the viscosity of the fluid, and a secondary magnetic field to reduce clumping of ferromagnetic particles.

Abstract: A valve for a magnetorheological fluid is formed with a duct through which the magnetorheological fluid can flow and which can be exposed to a variable magnetic field such that the flow resistance of the duct can be set using the magnetic field in the duct. The magnetic field can be lastingly generated using a magnet device that is made at least in part of magnetically hard material. The magnetization of the magnet device can be lastingly modified by a magnetic pulse of a magnetic field generation device in order to lastingly change the magnetic field in the duct and thus the flow resistance of the duct. A valve of the invention requires energy only to change settings while a specific setting can be lastingly maintained without supplying energy.

Abstract: A valve device is formed with a through-channel and a field generating device. A fluid which can be influenced by a field is provided in the through-channel and the field generating device is configured to act on the field-influenced fluid in the through-channel by way of a field. At least one adjustment device is provided with which the field that is active in the through-channel can be adjusted. A portion of the cross-sectional area of the through-channel can be adjusted, the portion being exposed to a field of a specific intensity so that the through-channel can also only partly be exposed to a field of a specific intensity. Thus, the through-channel, as seen in the direction of the flow, can be divided into regions of different flow resistance, whereby characteristic curves, which were previously attained only with difficulty, are easily obtained when using the valve device in a damper, for example.

Abstract: An ER fluid valve includes a housing and a plurality of parallel flow passages through the housing each defined by spaced electrodes at least one of which is controllable independently of other flow passages electrodes. A controller is configured to selectively establish electrical fields for all of the independently controllable electrodes to close all of the flow passages to ER fluid flowing through the housing. By removing the fields from all of the independently controllable electrodes, all the flow passages are open to the ER fluid flowing through the housing. By establishing fields for select independently controllable electrodes to close their associated flow passages and by leaving other flow passages open, restricted flow of the ER fluid through the housing is accomplished to vary the flow rate through the housing.

Abstract: Methods and devices for using one or more fluidic channels for generating binary states are described. In particular, the present teachings relate to incorporating such fluidic channels into devices that use the generated binary states in various applications.

Abstract: An air to liquid regulator valve for use with a vapor recovery system that recovers vapors expelled from a vehicle receiving fuel through a fuel supply passage and returns the vapors to an underground storage tank through a vapor return passage in a service station environment. The regulator valve includes a housing defining a fuel flow path in fluid communication with the fuel supply passage and a vapor return path in fluid communication with the vapor return passage, a vapor return orifice defined by the housing and disposed between a first portion and a second portion of the vapor return path, and a vapor flow bypass in fluid communication with the first portion and the second portion of the vapor return path such that the flow of vapors through both the vapor flow bypass and the vapor return orifice is possible.

Abstract: Disclosed embodiments include electromagnetic flow regulators for regulating flow of an electrically conductive fluid, systems for regulating flow of an electrically conductive fluid, methods of regulating flow of an electrically conductive fluid, nuclear fission reactors, systems for regulating flow of an electrically conductive reactor coolant, and methods of regulating flow of an electrically conductive reactor coolant in a nuclear fission reactor.

Abstract: A fuel pressure regulation system for a motor vehicle includes a fuel pressure regulator in communication with an electronic control device (ECU). The regulated pressure of the fuel pressure regulator can be varied by applying electrical signals from the ECU. According to one embodiment, a length of a spring is adjusted to vary the regulated fuel pressure. According to another embodiment, a viscosity of a fluid is adjusted to vary the pressure.

Abstract: Embodiments include electromagnetic flow regulators for regulating flow of an electrically conductive fluid, systems for regulating flow of an electrically conductive fluid, methods of regulating flow of an electrically conductive fluid, nuclear fission reactors, systems for regulating flow of an electrically conductive reactor coolant, methods of regulating flow of an electrically conductive reactor coolant in a nuclear fission reactor, and methods of fabricating an electromagnetic flow regulator for regulating flow of an electrically conductive fluid.

Abstract: Disclosed embodiments include electromagnetic flow regulators for regulating flow of an electrically conductive fluid, systems for regulating flow of an electrically conductive fluid, methods of regulating flow of an electrically conductive fluid, nuclear fission reactors, systems for regulating flow of an electrically conductive reactor coolant, and methods of regulating flow of an electrically conductive reactor coolant in a nuclear fission reactor.

Abstract: A movement damping apparatus has a flow path through which a magnetorheological fluid is pressed. A device that generates a variable magnetic field has a core around which a coil is wound as well as pole surfaces in the flow path. The magnetic field acts on the magnetorheological fluid by way of the pole surfaces. The coil is arranged within the flow path along with the core, the axis of the coil extending perpendicular to the direction of flow of the magnetorheological fluid. The flow path has a jacket made of a magnetically conducting material.

Abstract: Disclosed embodiments include electromagnetic flow regulators for regulating flow of an electrically conductive fluid, systems for regulating flow of an electrically conductive fluid, methods of regulating flow of an electrically conductive fluid, nuclear fission reactors, systems for regulating flow of an electrically conductive reactor coolant, and methods of regulating flow of an electrically conductive reactor coolant in a nuclear fission reactor.

Abstract: A valve for magnetorheological fluids is formed with a control duct in which the magnetic field of a magnetic device, consisting of a permanent magnet and coil, acts on the fluid. The viscosity of the fluid is directly proportional to the magnetic field strength, with the result that the flow resistance of the valve can be varied via the coil current. The respective control duct is arranged in the end-face region of the coil and runs radially with respect to the center line of the valve, with the result that high flux densities can be achieved in the control duct. A permanent magnet is arranged in the inner space of the coil and, even under currentless operating conditions, can close the valve up to a certain blocking pressure.

Abstract: A fluid control device for a fluid supply includes a housing (31) defining a fluid supply channel (34) with a fluid inlet (35) for coupling to a fluid supply and a fluid outlet (36) for coupling to an appliance. The housing additionally defines a chamber (44) with an inlet (40) for coupling to an overflow and an outlet (41) for coupling to a drain. A valve (55) is located in the fluid supply channel (34) and is moveable from a first open position to a second closed position where fluid flow through the channel (34) is substantially restricted. An actuator (52) is provided in the chamber (44) and is moveable from a first position to a second position. The valve (55) and actuator (44) are magnetically coupled to one another such that movement of the actuator (44) from the first position to the second position causes the valve (55) to move from the open position to the closed position.

Abstract: A teeter-totter valve device for metering magnetic particles from a hopper includes (i) a tube connected to the hopper for flow of magnetic particles out of the hopper; (ii) a teeter-totter member having a first arm including a first distal end, and a second adjustable arm including a second distal end; (iii) a support assembly supporting the teeter-totter member on and spaced from the tube; (iv) a first magnet located at the first distal end; (v) a second magnet located at the second distal; and (vi) a moving assembly for moving each of the first magnet and the second magnet towards and away from a first near point and a second near point on the tube to create or remove a point magnetic field and magnetic particles dam within the tube, thereby stopping or allowing flow of a desired quantity of magnetic particles past the first near point and past the second near point.

Abstract: A control lever (10) is provided with a grip (12), which in a joint (14) having two degrees of freedom is supported in a housing (11) and can be switched from an initial position in various directions for activating shift elements (18, 19), whereby spring elements (41, 42) are provided for returning the grip (12) to its initial position, and with a functional device for overcoming a pressure point during the activation and/or for retaining a desired shift position. In order to provide functional devices in greater numbers in a gearshift lever of this type without requiring substantially more installation space or substantially higher costs, provision is made that the functional device is constituted by an electrically controllable hydraulic arrangement (35), which connects to diametrically opposing shift elements (18, 19), which can be activated by the grip (12) in two opposing directions of motion.

Abstract: One embodiment of the invention provides a fluid control device for a fluid supply, the device comprising: a housing (31) defining a fluid supply channel (34) with a fluid inlet (35) for coupling to a fluid supply and a fluid outlet (36) for coupling to an appliance, the housing additionally defining a chamber (44) with an inlet (40) for coupling to an overflow and an outlet (41) for coupling to a drain; a valve (55) located in said fluid supply channel (34) and moveable from a first open position to a second closed position where fluid flow through the channel (34) is substantially restricted; an actuator (52) provided in said chamber (44) and moveable from a first position to a second position, wherein the valve (55) and actuator (44) are magnetically coupled to one another such that movement of the actuator (44) from said first position to said second position causes the valve (55) to move from said open position to said closed position.

Abstract: A magnetostatic actuator uses a ferrofluid slug confined in a cylindrical tube which is wrapped in a conducting coil. By applying a current to the coil, a magnetic field is generated inside the coil. The ferrofluid slug may be attracted to the interior of the coil by the interaction of its magnetic moment with the field generated inside the coil. Movement of the ferrofluid slug in response to the magnetic field may be used to actuate various devices, such as a droplet dispenser.

Abstract: The additional control valve device has a valve element which is guided between a gantry magnet and a trapping magnet in a reversibly movable manner in the direction of the longitudinal axis. An encircling seal is arranged on that side of the housing, in which the gantry magnet is arranged, which faces the valve element.

Abstract: An airbag inflation apparatus includes a chamber for generating a gas to inflate an airbag. A valve, including a magnetic fluid and a source of magnetic field, preferably an electromagnet, is associated with the chamber for regulating the flow of the gas into the airbag. A sensor determines and feeds occupant information to the sensor.

Abstract: A magnetorheological fluid delivery system includes a mixing and tempering vessel. Fluid is admitted to the vessel via a plurality of tangential ports, creating a mixing of the fluid in the vessel and promoting homogeneity. Fluid may be reconstituted in the vessel by metered addition of carrier fluid. A fixed-speed centrifugal pump disposed in the vessel pressurizes the system. Fluid is pumped through a magnetic-induction flowmeter and a magnetic flow control valve having solenoid windings whereby MR fluid is magnetically stiffened to restrict flow. A closed-loop feedback control system connects the output of the flowmeter to performance of the valve. A nozzle having a slot-shaped bore dispenses MR fluid for re-use in the work zone.

Abstract: Downhole wellbore tools are actuated by electrically controllable fluids energized by a magnetic field, for example. When energized, the viscosity state of the fluid may be increased by a degree depending on the fluid formulation. Reduction of the controllable fluid viscosity by terminating a magnetic field acting upon the fluid may permit in situ wellbore pressure to actuate a downhole device, such as a wellbore packer.

Abstract: A system for dispensing magnetorheological fluid to an MR finishing machine includes a pump for pressurizing the system; a first magnetic valve for regulating MR fluid flow by magnetically varying the structure and apparent viscosity of the fluid through a first flow passage; a similar second magnetic valve magnetically controlling a second flow passage in line with the first valve and flow passage; a pressure sensor disposed between the first and second valves; and an electronic control means. MR fluid flow through the system is controlled to a predetermined flow rate solely by the first valve. When the second valve is deactivated, a reference pressure is determined and saved. When the second valve is activated, a second pressure is determined and saved. From the pressure difference, the solids concentration of the fluid is determined, and a computer algorithm adds a calculated amount of water to the fluid reservoir as needed.

Abstract: The disclosure describes a magnetorheological fluid control valve. The magnetorheological fluid control valve comprises an electromagnetic coil having a first end and a second end. A first arm is magnetically coupled to the first end of the electromagnetic coil. A second arm is magnetically coupled to the second end of the electromagnetic coil. The second arm has a passage. A ferromagnetic rod having a diameter less than that of the passage is disposed in the passage and magnetically coupled to the first and second arms. A first manifold is coupled to the second arm at one end of the passage. A second manifold is coupled between the second arm and the first arm at an end of the passage opposite the first manifold. A magnetorheological fluid is disposed in the passage.

Abstract: The invention provides a magnetorheological damper assembly and piston. The assembly includes a housing with a fluid carried therein, a piston slidably carried in the housing, a rod and a valve both operably attached to the piston. The piston includes at least one passageway formed therein. The valve includes at least one bypass opening formed therein and at least one variable opening formed between a piston surface and the valve. The valve provides asymmetric fluid flow through the passageway. During operation, the variable opening selectively restricts fluid flow and the bypass opening maintains fluid flow through the passageway.

Abstract: Downhole wellbore tools are actuated by electrically controllable fluids that are energized by a magnetic field. When energized, the viscosity state of the fluid may be increased by a degree depending on the fluid formulation. Reduction of the controllable fluid viscosity by terminating a magnetic field acting upon the fluid may permit in situ wellbore pressure to displace a tool actuating piston. When the field is de-energized, the controllable fluid viscosity quickly falls thereby permitting the fluid to flow through an open orifice into a low pressure receiving volume. In an alternative embodiment of the invention, an expandable volume fluid may be used against a slip actuating element in the same manner as a fluid pressure motor.

Abstract: A magnetic control valve is provided in a suction powered pool cleaner of the type for vacuuming dirt and debris from submerged floor and side wall surfaces of a swimming pool. The pool cleaner comprises a head defining a suction inlet for vacuum inflow of water and debris into a plenum chamber, and further through a suction tube adapted for connection via a vacuum hose to a conventional pool water filtration system. The control valve includes an oscillatory valve member movable between open and substantially closed positions relative to an upstream end of the suction tube to produce pressure fluctuations causing the cleaner to advance in steps over submerged pool surfaces. Oscillatory driving of the valve head is assisted by permanent magnets mounted on the valve member and cleaner head to generate repulsion forces as the valve head respectively approaches the open and closed positions.

Abstract: A magneto-rheological damping device comprises a core element for carrying a magnetic flux and a magnetic flux generator positioned adjacent to a portion of the core element and operable to generate a magnetic flux in the core element. A sleeve is positioned over the core element and magnetic flux generator and includes a plurality of protrusions extending generally radially outwardly from a center of the core element. A flux ring surrounds the core element and sleeve and defining a passage between flux ring and core element for the flow of a magneto-rheological fluid. The sleeve protrusions are configured to engage the flux ring and secure the flux ring in a concentric position around the core element and sleeve.

Abstract: A flow control valve assembly for an electro-rheological (ER) fluid has an inlet port, an outlet port and a flow path for ER fluid extending between the inlet and outlet ports. A flow control valve is disposed in the flow path and includes a resilient diaphragm, which is acted upon by pressure in the flow path and which is moveable towards and away from the free end of a hollow boss. A flow restrictor in the form of an annular passage defined by electrodes is disposed in the flow path upstream of the flow control valve. An electric field is applied to the ER fluid as it passes between the electrodes to enable control of the resistance to flow of the ER fluid therethrough, thereby enabling control of the pressure drop across the diaphragm. A bypass passage defining a pressure relief valve is disposed downstream of the flow restrictor and permits flow between the inlet and outlet ports when the flow control valve is closed.

Abstract: A gap part is formed between a magnetic plate and a moving core in a solenoid part, a magnetic fluid whose viscosity is increased by the influence of the magnetic force is filled in the gap part, the viscosity of the magnetic fluid is increased by the influence of the magnetic force when the solenoid is energized, and the speed of a moving core to be attracted by a fixed core is reduced.

Abstract: A method and system for controlling the flow of a gaseous medium through a fluid are described. The method includes providing a rheologic fluid through which a gaseous medium can be conducted, and controlling the viscosity of the rheologic fluid to control the flow of the gaseous medium. The system has a rheologic fluid, which is located in particular in a device to be controlled, a guide guiding the gaseous medium through the fluid, and a field applier for applying a field at least partially in the area of the rheologic fluid.

Abstract: A controllable valve assembly (18) applicable in Magnetorheological (MR) fluid devices (20), such as MR mounts and MR dampers. The valve assembly (18) includes a valve body (32) having a magnetic circuit (40) contained therein which carries magnetic flux .phi., a controllable passageway (42) within the magnetic circuit (40), a MR (magnetically controlled) fluid (44) including soft-magnetic particles in a liquid carrier contained in the controllable passageway (42), a magnetic flux generator, such as a wound wire coil (46), generating magnetic flux .phi. which is directed through the MR fluid (44) in the controllable passageway (42) thereby generating "rheology" changes causing restriction in flow of MR fluid (44) therethrough.

Abstract: An adjustable valve including a passageway, a field responsive fluid within the passageway, and flow adjustment of the fluid through the passageway. In another aspect, the valve is in a vibration damper. In yet another aspect, the damper includes a body, a piston, first and second chambers, a damping valve, a piston rod, an auxiliary chamber, a passageway interconnecting to the auxiliary chamber, a field responsive fluid, a field responsive fluid valve for controlling flow to the auxiliary chamber, and pressurization means. Preferably included is a cavity partition having field responsive fluid disposed on one side and non-field responsive fluid disposed on the other. This allows a reduction of MR fluid allowing use of lighter-weight, less-expensive, hydraulic fluids for flow through the piston's damping valve. In another aspect, the damper includes mechanical adjustment device for manually adjusting a damping level.

Abstract: The present invention provides a use of an electro-sensitive movable fluid, that is, a micromotor, a linear motor, a micropump and a method of using the micropump, a microactuator, and an apparatus which these devices are applied to, and a method and an apparatus of controlling flow properties of a fluid.

Abstract: A controllable valve assembly (18) applicable in Magnetorheological (MR) fluid devices (20), such as MR mounts and MR dampers. The valve assembly (18) includes a valve body (32) having a magnetic circuit (40) contained therein which carries magnetic flux .PHI., a controllable passageway (42) within the magnetic circuit (40), a MR (magnetically controlled) fluid (44) including soft-magnetic particles in a liquid carrier contained in the controllable passageway (42), a magnetic flux generator, such as a wound wire coil (46), generating magnetic flux .PHI. which is directed through the MR fluid (44) in the controllable passageway (42) thereby generating "rheology" changes causing restriction in flow of MR fluid (44) therethrough.

Abstract: A gas flow valve comprises at least one gas inlet, at least one gas outlet, a flow path between said gas inlet and said gas outlet, a magnetic fluid in the valve arranged in the flow path and means for application of a magnetic field to the magnetic fluid. The magnetic fluid solidifies upon application of the magnetic field, interrupts the flow path from at least one gas inlet to at least one gas outlet gas-tight and permits gas flow when no magnetic field is applied.

Abstract: A method and apparatus for filling a container with toner using a series of traveling magnetic fields to control the flow of toner from a supply of toner to the container. Initially, an empty container is placed under a fill tube through which the toner will be supplied to the container. In the filling process the traveling magnetic fields, which are supplied by turning on and off a series of solenoids, and gravity cause toner from the toner supply to move through the fill tube. When a solenoid is turned on toner particles are attracted to its magnetic field where a plug of toner is formed. The solenoids are controlled so that a discrete amount of toner is supplied in each on/off cycle of the solenoids. The solenoid on/off cycle is repeated until the container is filled with toner. When the container is filled, the appropriate solenoid is activated so that a plug of toner stops the flow of toner in the fill tube.

Abstract: A device is described for generating operating states characterized by dirences in height in actuators arranged in a matrix. In order to enable operating states which are characterized by differences in height to be produced in mechanical actuators in close matrix-type arrangement which are controllable selectively and independently from one another in a simple manner in a suitable device a reservoir filled with electroviscous liquid has an over-pressure chamber and a negative-pressure chamber and these chambers are connected via separate control ducts with hydraulic cylinders of the actuators, the connection to the two chambers of the reservoir being opened or blocked alternatively by the two control ducts of an actuator via a first electrode and a second electrode and a controllable center electrode common to both. The pressure variation formed in this way changes the vertical adjustment of a mechanical pin via an elastomer diaphragm.

Abstract: An electrorheological device capable of containing an electrorheological fluid between two electrodes and having members for applying an electrical potential between the electrodes, characterised in that the device has members for subjecting the fluid to varying compressive or tensile stress in operation.

Abstract: A variable discharge pump (3) comprises a piston (4) reciprocable within a cylinder (2), a displaceable inlet valve (5) adapted to control admission of lower pressure hydraulic fluid (9) to the swept volume areal (10) of the piston (4) and cylinder (2), a displaceable outlet valve (7) adapted to control delivery of higher pressure fluid (9) from the swept volume area (10), and means (13, 13A, 26-28, 29-44) to control the position of the inlet valve (5) so as to control the volume of fluid (9) delivered by the pump (3) in accordance with demand.

Abstract: A valve for regulating the flow of materials which are made up substantially of magnetic particles. The valve includes an outer housing and a core assembly secured within the housing to define an annular flow passage therebetween. The core assembly supports an improved magnet/coil assembly. The magnet/coil assembly includes a permanent magnet positioned between a pair of pole pieces and has an electromagnetic coil surrounding the permanent magnet. When energized, the coil establishes a counteracting magnetic field to cancel the magnetic field of the permanent magnet, which allows an open flow condition in the valve. An annular cavity is defined between the permanent magnet and the coil, which provides for a flux leakage path for the permanent magnet. During an open condition, the flux from the permanent magnet is shunted across the cavity to reduce the flux to be counteracted by the coil's magnetic field and therefore reduce the power consumed by the valve.

Abstract: A variable displacement pump (3) comprises a piston (4) reciprocable within a cylinder (2), a displaceable inlet valve (5) adapted to control admission of lower pressure hydraulic fluid (9) to the swept volume area (10) of the piston (4) and cylinder (2), a displaceable outlet valve (7) adapted to control delivery of higher pressure fluid (9) from the swept volume area (10), and means (13, 13A, 26-28, 29-44) to control the position of the inlet valve (5) so as to control the volume of fluid (9) delivered by the pump (3) in accordance with demand.

Abstract: A hydraulic valve tappet for an internal-combustion engine has a high-pressure valve through which an electroviscous fluid flows as a function of an electric voltage. In this case, a piston is displaced which is connected with a charge cycle valve so that the valve stroke is continuously variable. Using an electronic control device, the valve stroke is influenced as a function of parameters of the internal-combustion engine.

Abstract: An E-R hydraulic control valve that has two or more surfaces that can be moved relatively to one another to adjust a flow orifice size while maintaining a control voltage gradient across the E-R fluid and to seat one surface against the other to shut off fluid flow. Combining movable mechanical fluid flow elements with E-R fluid control allows initial tuning of the valve to a particular application by mechanical restriction of an orifice, and E-R operating control of the fluid. Seating the mechanical surfaces provides a fail-safe shut-down mode.

Abstract: An apparatus and method for controlling the amount and concentration of make-up water and chemicals introduce into the recirculating water of a cooling tower system. A float operated make-up valve controls the addition of make-up water to the tower. As make-up water is added to the tower a vacuum is produced at an injector valve which draws chemicals from a chemical holding tank into the make-up water, thereby allowing precise control of the chemical concentration in the make-up liquid. Further, a bleed valve is provided which is responsive to the vacuum produced at the injector valve and bleeds a portion of the recirculating water to waste.

Abstract: A pressure regulating inlet-and-outlet valve for a sealed space enclosed by a housing wall (10). The wall is penetrated by at least one gap (6) that is spanned by a magnetic field and completely occupied by a ferrofluidic liquid (7) confined inside the gap by the field.

Abstract: A general electro-rheological valve is disclosed used in controlling the flow of fluids in a variety of applications. The valve comprises an inlet in communication with a fluid source, an outlet for transporting the fluid out of said valve, and an oscillating valve member for opening and closing off said inlet. The valve member has a cavity containing an electro-rheological fluid, a perforated electrode member emersed in the electro-rheological fluid within the cavity, and means for electrifying the perforated electrode member such that the electro-rheological fluid within the electrode solidifies, thereby locking the position of the valve member relative to the electrode. In this manner, the valve member, which oscillates with respect to the perforated electrode member, can be frozen in an open, closed, or intermediate position with respect to the inlet. The valve member thereby controls the level of fluid flow through the valve.

Abstract: Magnetic valve and methods related thereto for regulating the physically unobstructed flow of ferromagnetic particulate solid materials through a conduit by means of an electromagnetic and/or permanent magnetic device for establishing and controlling a magnetic field, which is caused to selectively pass along a magnetic circuit which comprises said particulate materials in said conduit to be regulated and wherein said magnetic field is deviated from said conduit or deactivated to allow the flow of said material.

Abstract: An ink jet recording head is provided with a discharge port for discharging liquid therethrough, a liquid path communicating with the discharge port, an energy generating member provided in the liquid path and generating energy for discharging the liquid, and a discharge amount control disposed on the liquid path on the side opposite to the discharge port with respect to the energy generating member and having a magnetic force generating member and magnetic fluid.