Abstract: An ink jet recording head wherein a nozzle jetting ink droplets is structured of a plurality of ink jet ports 11, and the length ln [m] of an ink jet port and pitch Pn [m] are set to satisfy the conditions ln>1.2 Vd/An and Pn>1.4 dd (where Vd is the volume of ink droplets that are jetted from one individual ink jet port [m3], dd is diameter of an ink droplet [m] and An is the area of a nozzle opening [m2]); wherein the fusion phenomena of a meniscus at the rear surface of a nozzle after ink is jetted can be suppressed; and wherein the effect of a multi-port nozzle enabling re-fill time to be reduced is utilized. Further the fusion phenomena of ink jet droplets in flight after being jet expelled from a multi-port nozzle can be suppressed enabling superior quality images to be recorded.

Abstract: A driving method for an ink jet printing head includes a vibration application step and an ink refresh operation step. In the vibration application step, small vibrations, which do not cause ink drop discharge from nozzles of the ink jet printing head, are applied to pressure-generation chambers of the ink jet printing head corresponding to nozzles which are not executing ink drop discharge. In the ink refresh operation step, ink refresh operation, for removing the ink in the nozzles and replacing the ink with fresh ink, is periodically executed according to a refresh operation cycle which is appropriately set based on the temperature and/or humidity measured around the ink jet printing head. The ink refresh operation is executed by means of forcible ink drop discharge from the nozzles, ink suction by a pump, etc. For example, the refresh operation cycle is set shorter as the temperature around the ink jet printing head gets lower and as the humidity around the ink jet printing head gets lower.

Abstract: An ink jet recording head and an ink jet recording apparatus used this head, in which ejectors are arrayed in a two-dimensional matrix, and the necessary width of each of plural common ink branch paths is reduced, and the density arraying the ejectors is made to be high, are provided. The ink jet recording head is formed by layering and adhering a nozzle plate, a common ink path plate, an ink supplying plate, a connecting path plate, a pressure chamber plate, a vibration plate, and piezoelectric actuators. The ink supplying plate is made of a resin film whose stiffness is low. Since the ink supplying plate also works as air dampers for the plural common ink branch paths, even when the width of each of the plural common ink branch paths is made to narrow, necessary and sufficient acoustic capacitance to prevent crosstalk from generating between adjacent two ejectors can be obtained. With this structure, the density arraying the ejectors is able to be high.

Abstract: In an ink jet recording head, an ink pool has a main flow path communicating with an ink supply port and a plurality of branch flow paths branching from the main flow path. Each ejector has a pressure chamber, a pressure generating unit and a nozzle. The pressure chamber communicates with the corresponding one of the branch flow paths. The pressure generating unit generates a pressure wave in ink charged into the pressure chamber. The nozzle ejects the ink from the pressure chamber compressed by the pressure wave. At least one wall surface forming each of the branch flow paths is formed of a damper member elastically deformable in accordance with the change of pressure in the branch flow path.

Abstract: The present invention provides an ink jet recording head drive method for applying a drive voltage to an electro-mechanical converter which changes a pressure within a pressure generation chamber filled with ink, so that an ink droplet is ejected from a nozzle communicating with the pressure generation chamber, wherein the drive voltage has a voltage waveform including: a first voltage change process for increasing a volume of the pressure generation chamber so as to pull the ink meniscus at the nozzle opening toward the pressure generation chamber; and a second voltage change process for decreasing the volume of the pressure generation chamber, so as to eject an ink droplet, and wherein the first voltage change process is preceded by a preparatory voltage change process for slightly pulling an ink meniscus from the nozzle opening toward the pressure generation chamber.

Abstract: To enable fine droplets each having a diameter of 15 &mgr;m or less to be ejected without causing increase of device cost and a device size, and decrease reliability and a manufacturing yield.

Abstract: An ink jet recording head includes an ink supply system, and a plurality of pressure chambers each including a nozzle for ejecting an ink droplet. The ink supply system has a flow resistance r satisfying the following relationship: r<800/(q·N·f) wherein q, N and f represent the droplet volume ejected from each nozzle, number of pressure chambers, and the ejection frequency, respectively. The ink jet recording head achieves a stable simultaneous ejection from all the nozzles at a higher frequency and for an ink having a higher viscosity.

Abstract: A nozzle for ejecting a droplet has a straight portion having a substantially straight shape. A driving waveform to be applied to a piezoelectric actuator includes a first voltage change process for expanding volume of a pressure generating chamber to retract a meniscus of the nozzle portion toward the pressure generating chamber and a second voltage change process for compressing the volume of the pressure generating chamber to eject a droplet. Voltage change quantity and voltage change time of the first voltage change process are set so that meniscus retraction quantity D when the second voltage change process is applied satisfies 0.8·ln≦D≦1.5·ln (ln designates length of the straight portion of the nozzle). Consequently, when the second voltage change process is applied, strong liquid surface interference can be produced in the nozzle central portion. Therefore, a droplet having an extremely small droplet volume can be ejected.

Abstract: An ink jet printing head includes a common ink channel and a plurality of ejectors (each of which includes a nozzle and a pressure generation chamber which is filled with ink supplied from the common ink channel) which are connected to the common ink channel for ejecting ink drops. The common ink channel is provided with an air damper, and acoustic capacitance Cp of the common ink channel per ejector is set based on acoustic capacitance Cn of the nozzle and acoustic capacitance Cc of the pressure generation chamber. For example, the acoustic capacitance Cp of the common ink channel per ejector is set so as to satisfy two conditions: Cp>Cn and Cp>20 Cc.

Abstract: To provide a driving method of an ink jet recording head and an ink jet recording apparatus capable of maintaining a satellite at the time of ejecting a big droplet always in a good flying condition without regard to a change in environment temperature, and also speeding up refill operation after ejecting the big droplet.

Abstract: An ink jet recording head has a plurality of ejectors and an ink supply system. Each of the plurality of ejectors has a pressure generating chamber, a nozzle communicating with the pressure generating chamber, and a pressure generating portion. The ejectors are arrayed two-dimensionally. The ink supply system has a common flow path with which a plurality of the ejectors are interconnected. The pressure generating chambers are filled with ink through the common flow path. A change of pressure is generated in the ink in the pressure generating chambers by the pressure generating portions. Thus, ink droplets are ejected from the nozzles. The common flow path is disposed to overlap the pressure generating chambers two-dimensionally. The common flow path has a constricted shape having wide portions and narrow portions.

Abstract: A fluid jetting device is comprised of: a plurality of chambers arranged in a matrix form; nozzles formed in the plural chambers, respectively; a fluid pressure applying portion arranged on at least one planes of the plural chambers; a plurality of fluid pool sub-streams for supplying fluids to the plural chambers; a fluid pool main stream connected to one edges of the plural fluid pool sub-streams; and a fluid supplying portion for supplying a predetermined fluid to the fluid pool main stream. The fluid supplying portion is connected to a portion of the fluid pool main stream in the vicinity of this fluid pool main stream along a longitudinal direction thereof.

Abstract: An inkjet recording head allowing a high driving efficiency and preventing a variation in the driving efficiency is disclosed. An piezoelectric actuator is provided for each ink nozzle and has a driving section disposed in an area of an ink pressure chamber, an electrode pad section, and at least one bridge section connecting the driving section and the electrode pad section. The pressure chamber has a plane shape having an aspect ratio approximately equal to 1, and the bridge section has a width of a connection area to the driving section set smaller than a width of a connection side of the driving section.

Abstract: In an ink jet recording head, an ink pool has a main flow path communicating with an ink supply port and a plurality of branch flow paths branching from the main flow path. Each ejector has a pressure chamber, a pressure generating unit and a nozzle. The pressure chamber communicates with the corresponding one of the branch flow paths. The pressure generating unit generates a pressure wave in ink charged into the pressure chamber. The nozzle ejects the ink from the pressure chamber compressed by the pressure wave. At least one wall surface forming each of the branch flow paths is formed of a damper member elastically deformable in accordance with the change of pressure in the branch flow path.

Abstract: An inkjet recording head includes a plurality of nozzles, a plurality of pressure chambers in communication with the respective nozzles, a diaphragm forming a part of the walls of the pressure chambers, and a plurality of piezoelectric actuators each coupled with a part of the diaphragm to form a vibrating member. The vibrating member deforms to generate a pressure wave in the ink filled within the pressure chamber, the acoustic capacitance of the vibrating member being set at 2.0×10−20 m5/N or higher.

Abstract: An ink jet recording head wherein a nozzle jetting ink droplets is structured of a plurality of ink jet ports 11, and the length ln [m] of an ink jet port and pitch Pn [m] are set to satisfy the conditions ln>1.2 Vd/An and Pn>1.4 dd (where Vd is the volume of ink droplets that are jetted from one individual ink jet port [m3], dd is diameter of an ink droplet [m] and An is the area of a nozzle opening [m2]); wherein the fusion phenomena of a meniscus at the rear surface of a nozzle after ink is jetted can be suppressed; and wherein the effect of a multi-port nozzle enabling re-fill time to be reduced is utilized. Further the fusion phenomena of ink jet droplets in flight after being jet expelled from a multi-port nozzle can be suppressed enabling superior quality images to be recorded.

Abstract: An ink jet recording head and an ink jet recording apparatus used this head, in which ejectors are arrayed in a two-dimensional matrix, and the necessary width of each of plural common ink branch paths is reduced, and the density arraying the ejectors is made to be high, are provided. The ink jet recording head is formed by layering and adhering a nozzle plate, a common ink path plate, an ink supplying plate, a connecting path plate, a pressure chamber plate, a vibration plate, and piezoelectric actuators. The ink supplying plate is made of a resin film whose stiffness is low. Since the ink supplying plate also works as air dampers for the plural common ink branch paths, even when the width of each of the plural common ink branch paths is made to narrow, necessary and sufficient acoustic capacitance to prevent crosstalk from generating between adjacent two ejectors can be obtained. With this structure, the density arraying the ejectors is able to be high.

Abstract: An ink jet printing head includes a common ink channel and a plurality of ejectors (each of which includes a nozzle and a pressure generation chamber which is filled with ink supplied from the common ink channel) which are connected to the common ink channel for ejecting ink drops. The common ink channel is provided with an air damper, and acoustic capacitance Cp of the common ink channel per ejector is set based on acoustic capacitance Cn of the nozzle and acoustic capacitance Cc of the pressure generation chamber. For example, the acoustic capacitance Cp of the common ink channel per ejector is set so as to satisfy two conditions: Cp>Cn and Cp>20 Cc.

Abstract: Ink stored in an ink tank 11 passes through a supply path 12 and supply port 13 and fills a pressure chamber 14. A piezoelectric actuator 15 vibrates a vibration plate 17 by receiving a voltage from a driving voltage control unit 16. The volume of the pressure chamber 14 is changed by vibrating the vibration plate 17 to eject the ink in the pressure chamber 14 from a nozzle 18 toward to the sheet 2. The diameter of the nozzle 18 is set within the range of 20 to 40 &mgr;m, and an ink viscosity is set within the range of 2 to 6 mPa·s. With these settings, a fine droplet having the total diameter of 25 &mgr;m or less can be stably ejected, thereby obtaining high quality image. In addition, a driving waveform voltage is corrected in accordance with the ambient temperature detected by a temperature detection unit 19, and the ink viscosity is set within the range of 2 to 15 mPa·s, thereby keeping high image quality.

Abstract: An ink jet recording head includes an ink supply system, and a plurality of pressure chambers each including a nozzle for ejecting an ink droplet.