Abstract: An ink jet recording head is used which has: a pressure chamber which is communicated with a nozzle opening of a nozzle plate and with a reservoir through an ink supply port; and a piezoelectric vibrator for, in response to a driving signal, producing volume displacement in the pressure chamber, the inertance Mn of the nozzle opening and the inertance Ms of the ink supply port having the relationship of 0.5<Mn/(Mn+Ms) is used. The meniscus is rapidly returned to the nozzle opening by an inertial energy which is due to the ink suction to the pressure chamber, so that the ink ejection is conducted in the vicinity of the nozzle opening, thereby enabling an ink drop which is substantially spherical to be ejected.

Abstract: A recording head having a nozzle plate which has a sufficient thickness not to be deformed by a pressure vibration, and which is provided with concave portions on the back side of the plate with remaining a thickness corresponding to the longitudinal length of a nozzle in which concave portions of the nozzle are disposed. The concave portions formed on the back of the nozzle plate are arranged independently for each nozzle to suppress the influence of the pressure applied to the other nozzles as much as possible by utilizing the buffer function of each of the concave portions.

Abstract: A method of driving an ink jet recording head comprising the steps of: retreating a vibrating plate to a predetermined position from a nozzle opening at such a speed as to allow a meniscus at the nozzle opening to be jetted from the nozzle opening while applying a drive voltage to a piezoelectric vibrating element; holding the vibrating plate at the position; and advancing the vibrating plate toward the nozzle opening when the meniscus has returned to a position 1/3 or more of the farthest retreat position thereof. As a result, a pressure chamber contracted to thereby apply pressure to ink when inertial stream of the ink become stable and heads toward the nozzle opening, producing an ink droplet to be jetted at a predetermined speed irrespective of the position of the meniscus.

Abstract: A printer using a line-type ink jet recording head. The line-type head has pressure producing chambers formed by dividing nozzle openings extending in a recording paper width direction with vertical side walls and upper and lower ink flow paths which communicate with each other through the pressure producing chambers and extend in a horizontal direction. Each ink flow path has an inlet for replenishing ink and an outlet for discharging the ink. A plurality of pressure producing elements are provided for applying varied pressures to the pressure producing chambers for jetting ink droplets. A sealing member selectively seals the nozzle openings by abutting on the nozzle openings when the recording head has been evacuated to a predetermined position.

Abstract: An ink jet recording apparatus and method having an ink jet head. The ink jet head includes a housing made of a material having a high coefficient of thermal conductivity, including at least one heat source, and arranged so as to confront a recording medium; an ink holding member arranged inside the housing, the ink holding member transmitting heat generated by the heat source to melt a solid-phase ink put into the housing for holding the molten ink by capillary action; a nozzle formed member being part of the ink holding member and having at least one nozzle orifice arranged so as to confront the recording medium; and a pressure generating member arranged within the ink holding member for generating a pressure which causes ink near the nozzle orifice to jet in the form of ink drops. The ink jet recording method is achieved by the apparatus thus constructed.

Abstract: An ink jet print head in which a portion along which both piezoelectric conversion elements and a nozzle forming member are adhesively fixed is positioned at least a distance exceeding that of a stress concentration region toward a base portion of the piezoelectric conversion elements from a vibrating fulcrum of the piezoelectric conversion elements. As a result, any thermally induced stress concentration in the piezoelectric conversion elements is diffused over the adhesively fixed stress that acts backward of such stress concentration region. This prevents each piezoelectric conversion element from being deformed, thereby contributing to eliminating variations in the nozzle gap.

Abstract: An on-demand type ink jet print head having a nozzle plate which is arranged horizontally so that its nozzle openings face upward and cantilevered vibrating members the free ends of which confront the nozzle openings. Ink is held by a capillary force in a gap between the vibrating members and the nozzle plate and is supplied by surface tension in a gap formed between a plurality of members from an ink tank up to the vicinity of the vibrating members. Since the ink is supplied by a capillary force between the ink level in the tank and the vibrating members, the ink supply is stable irrespective of the ink level in the tank. Further, since the ink is ejected in the form of ink droplets produced by a dynamic pressure associated with vibration of the vibrating members within the ink, it is possible to produce fine ink droplets.

Abstract: An ink jet recording apparatus and method having an ink jet head. The ink jet head includes a housing made of a material having a high coefficient of thermal conductivity, including at least one heat source, and arranged so as to confront a recording medium; an ink holding member arranged inside the housing, the ink holding member transmitting heat generated by the heat source to melt a solid-phase ink put into the housing for holding the molten ink by capillary action; a nozzle formed member being part of the ink holding member and having at least one nozzle orifice arranged so as to confront the recording medium; and a pressure generating member arranged within the ink holding member for generating a pressure which causes ink near the nozzle orifice to jet in the form of ink drops. The ink jet recording method is achieved by the apparatus thus constructed.

Abstract: An ink jet print head is provided having a nozzle forming substrate with a plurality of nozzles formed therein. Vibrators formed on a piezoelectric transducer disposed within the ink jet print head opposite the nozzles are independently drivable. A first gap is formed between the nozzle forming substrate and a vibrator in a region adjacent the nozzles. A second gap is formed between the nozzle forming substrate and a vibrator at a region away from the nozzles having a different dimension than the first gap.

Abstract: A device detects an air-fuel ratio of a fuel mixture by causing an electric current to flow through an oxygen ion-conductive solid electrolyte to cause migration of oxygen ions between an atmospheric air and a gas receiving portion into which the exhaust gases resulting from combustion of the fuel mixture are diffused via gas diffusion restricting means. The device includes means for detecting the electric current.

Abstract: In order for increased precision control of air/fuel ratio, a pump electric current indicative voltage and a pump electric voltage are selectively used as an air/fuel ratio indicative signal in such a manner that the pump electric voltage is used at the stoichiometry, while the pump electric current indicative voltage is used as the air/fuel ratio indicative signal at an air/fuel ratio other than the stoichiometry. According to another aspect of the invention, the pump electric current indicative voltage is offset in response to step change in the pump electric voltage to generate an air/fuel ratio indicative signal which changes rapidly at the stoichiometry.

Abstract: An air/fuel ratio monitoring system in an IC engine, using an oxygen sensor of the concentration cell type which has an inner electrode layer, a microscopically porous layer of oxygen ion conductive solid electrolyte, and an outer electrode layer to be exposed to the exhaust gas and exhibits a sharp change in the level of output voltage in response to a change in the air/fuel ratio in the engine across the stoichiometric ratio. To ensure accurate monitoring of the air/fuel ratio even though an average level of the sensor output changes for various reasons such as aging of the sensor, the monitoring system produces a variable reference voltage. The output of the oxygen sensor is compared with this reference voltage by first adding or subtracting a fixed voltage to the output voltage of the sensor, depending on the result of comparison between the sensor output. The resultant reference voltage and voltage is then smoothed in an RC circuit.

Abstract: A system for detecting the concentration of oxygen in a gas which comprises an oxygen sensor having a first solid electrolyte cell, which produces an electrical output representing a difference between oxygen partial pressures on the opposite two sides of a solid electrolyte layer, and a second solid electrolyte cell which acts as an oxygen ion pump by application of a current thereto and is used to control the oxygen partial pressure in a fraction of the gas admitted into the sensor. The current is controlled so as to render the output of the oxygen sensor equal to a target value. The system includes means for continuously making a judgement whether the gas under inspection is equivalent to the air or not. When the atmospheric condition of the gas is established the target value is varied so as to avoid undesirable increase in the current intensity. This is favorable for durability of the oxygen sensor.

Abstract: A feedback control is effected during warming-up operation so as to adjust an actual air-fuel ratio to a target value. A sensing element is used to probe exhaust gases to detect an air-fuel ratio of a fuel-rich mixture that is required for warming up the engine. The amount of fuel injection is corrected so that the actual air-fuel ratio is adjusted to a target value displaced to the rich side from the stoichiometric ratio.

Abstract: A control system for a motor vehicle is disclosed wherein the parameters for optimum operation for an engine are determined based upon an acceleration position and a vehicle speed, and a continuously variable transmission is operated to vary a drive ratio in such a manner as to cause the engine to operate according to those parameters.

Abstract: An air/fuel ratio monitoring system in an IC engine, using an oxygen sensor of the concentration cell type which has a laminate comprising an inner electrode layer, a microscopically porous layer of oxygen ion conductive solid electrolyte and an outer electrode layer exposable to exhaust gas and which exhibits a sharp change in output voltage level in response to a change in the air/fuel ratio in the engine across a stoichiometric ratio.

Abstract: An air/fuel ratio detection system for an IC engine, using an oxygen sensor element of the concentration cell type which has a laminate of a measurement electrode layer exposed to the exhaust gas, a porous layer of oxygen ion conductive solid electrolyte and a reference electrode layer and requires the supply of a small DC current thereto to produce a reference oxygen partial pressure at the reference electrode by a balance between migration of oxygen ions to the reference electrode and diffusion of oxygen molecules therefrom.