Abstract: According to the present invention, a liquid jet recording head assembly method comprises the steps of assembling a pressing member with a reference member to which an element substrate is fixed, charging a forcing spring provided for the pressing member to obtain a gap through which a grooved top plate can be inserted, assembling, by means of the gap, the grooved top plate with the element, and releasing the charging of the forcing spring and using the force exerted by the forcing spring to press the grooved top plate against the element substrate, so as to secure the grooved top plate to the element substrate.

Abstract: An ink jet recording head comprises a discharge port for discharging ink, two electrothermal converting elements for generating thermal energy utilized for discharging the ink, and an ink flow path provided with the two electrothermal converting elements, at the same time, being conductively connected with the discharge port, and this head has a first discharge mode for discharging liquid droplets from the discharge port when the electrothermal converting element on the side nearer to the discharge port, of the two electrothermal converting elements, receives driving signals to generate the thermal energy, and also, a second discharge mode for discharging liquid droplets from the discharge port in the larger discharge amount than that of the first mode when both of the two electrothermal converting elements receive driving signals to generate the thermal energy.

Abstract: An ink-jet recording head comprises a plurality of liquid flow paths having discharge openings for discharging an ink, and a plurality of thermoelectric transducers provided for each liquid flow path in order to discharge the ink, wherein, a frontward thermoelectric transducer located on the discharge opening side is so provided that, when the ink is discharged by the frontward thermoelectric transducer alone, a value of (discharge velocity v/discharge quantity Vd) with respect to a distance OH extending from an end of its discharge opening side to the discharge opening is at a distance OH of the first region in a regional classification into a first region in which the value of v/Vd increases with a decrease in the distance OH and a second region in which it comes to be substantially constant with an increase in the distance OH.

Abstract: A high-toughness ZrO.sub.2 sintered body having a stress-induced transformation ratio of 25% or more, which consists essentially of 40-90 volume % of ZrO.sub.2 containing 0.1-3 mol % of Nd.sub.2 O.sub.3 and 0.5-3.5 mol % of Y.sub.2 O.sub.3 as stabilizers of the crystal structure of ZrO.sub.2, and 10-60 volume % of at least one of Al.sub.2 O.sub.3, SiC, TiC, B.sub.4 C and TiB.sub.2.

Abstract: A superfinishing machine using lapping film applied in superfinishing of the surface to be polished of the work which is rotated or turned reciprocally. The rotating direction of a pair of take-up reels for lapping film is changed over and controlled by the driving changeover means, and in cooperation with this changeover control, the follower friction wheels becoming the driven side are controlled by braking means. As a result, the whole grain surface of the lapping film can be used effectively. Besides, excessive withdrawal of the lapping film can be effectively prevented. There is also pressing means for pressing the lapping film against the surface to be polished of the work, so that high-precision polishing along the contour of the surface is realized.

Abstract: A connection apparatus mainly comprises a gas-tight container one surface of which is made of a film, a gas supply source for filling the container with a gas at a predetermined pressure, and a heat source. Two substrates, at least one of which is flexible, are tightly supported on the film surface of the container in such a manner that electrodes or terminals formed on the both substrates confront with each other. The gas pressure in the container is increased to the predetermined value, thereby to tightly contact the electrodes formed on the both substrates with each other. Thereafter, the heat source is enabled to melt the electrodes and to electrically connect the two substrates with each other.