JPS6223668B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a recording apparatus using an inkjet, and more particularly to an improvement in a recording head for an inkjet having a multi-nozzle structure.

Many ink-on-demand type inkjet printers use recording heads having a multi-nozzle structure to facilitate the recording of characters in a dot matrix format. However, in such a recording head with a multi-nozzle structure, each nozzle is connected to a common ink chamber via a pressure chamber, so when a certain nozzle is selected to eject ink, the pressure chamber for the selected nozzle is The pressure increase spreads to other nozzles through the common ink chamber on the opposite side of the nozzle, and not only changes the ejection timing and amount of ejected particles of other nozzles, but also changes the ejection time of one nozzle and the simultaneous ejection of all nozzles, for example. Due to the large pressure fluctuations over time, the required ink ejection speed cannot be achieved, and the timing for recording characters is therefore delayed. Therefore, it has been a problem in the past to quickly attenuate the pressure fluctuations generated in the residual ink immediately after the ink is ejected, and various countermeasures have been used. As a specific example, a method has been adopted in which a flexible member, that is, an elastic member is used inside the common ink chamber or outside the common ink chamber to absorb this pressure fluctuation. However, it must be said that the effects are only a step forward.

SUMMARY OF THE INVENTION In view of the above points, it is an object of the present invention to provide an improved inkjet recording head that quickly attenuates fluctuations in ink pressure within the inkjet recording head.

This purpose includes a plurality of nozzles that eject ink, a plurality of conduction paths that introduce the ink into each of the nozzles, and a plurality of nozzles that eject the ink from each nozzle through the respective conduction paths. A pressure chamber, and a plurality of supply channels for supplying the ink from the common ink chamber to the pressure chamber are formed by grooves bored in the plate-like body, and are further arranged on the outer periphery of the pressure chamber. This is achieved by an inkjet recording head equipped with a piezoelectric element, wherein at least a portion of the supply path is made of a flexible member.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The most preferred specific embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing the structure of an inkjet recording head equipped with seven nozzles according to the present invention. The operating principle will be outlined using FIG.
A pulse voltage generated by a drive device 3 according to an input signal 2 is applied to a piezoelectric element 1 (representatively designated by a symbol), and at that time, the piezoelectric element 1 is When pressure is applied to the pressure chamber 4 covered by the pressure chamber 4, the pressure of the ink within the pressure chamber 4 increases, and the ink is ejected from the nozzle 6 through the ink guide path 5. This is a case where a pulse is applied to the piezoelectric element 1 and the pressure increases, but conversely, a moment when the pulse disappears immediately occurs. In this case, ink is sucked into the pressure chamber 4, and the state thereof will be explained. When ink is ejected from the nozzle 6, the pulse application to the piezoelectric element 1 is stopped and the pressure inside the pressure chamber 4 decreases, and the ink inside the nozzle 6 and the ink conduction path 5 flows in the opposite direction to the ejection direction, that is, the pressure chamber. Try to move to the 4th side. However, the adhesive force generated between the ink and the inner wall of the nozzle 6, the inertia of the ink itself, and the surface tension of the ink at the tip of the nozzle prevent the ink from moving toward the pressure chamber 4, that is, prevent the valve from working. Eggplant. Therefore, as the pressure in the pressure chamber 4 decreases, ink in the common ink chamber 7 flows into the pressure chamber 4 via the ink supply path 8. Ink is ejected in accordance with the pulse application by repeating the process of ejecting ink with the next pulse and inhaling it again. It goes without saying that the increase in pressure in the pressure chamber 4 immediately before ink jetting also occurs in the opposite direction to the ink jetting direction, that is, the pressure in the common ink chamber 7 also increases via the ink supply path 8. In order to prevent pressure fluctuations in the common ink chamber 7 and to reduce the influence of the injecting nozzle on other nozzles, in the present invention, at least a portion of the ink supply path 8 near the pressure generation source is connected to A-A' in FIG. It is constructed of a flexible material 9 as shown in the cross-sectional view of FIG. 2 along a line. The flexible material 9 is made of vinylidene chloride or butyl rubber, for example, and the outside of the flexible material 9 is pressed by a press plate 10. The holding plate 10 is the supply path 8
A hole 11 for allowing the flexible sheet 9 to deform is provided at a position corresponding to .

By using the inkjet recording head according to the present invention, the pressure fluctuations generated by the piezoelectric element are attenuated faster by the flexible material, the pressure fluctuations exerted on the ink chamber are reduced, and the ejection period, that is, the frequency characteristics are improved. At the same time, it is possible to reduce the variation in the jetting speed and improve the printing quality, which is a great practical effect.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an inkjet recording head according to the present invention, and FIG. 2 is a cross-sectional view taken along the line A--A' in FIG. 1; piezoelectric element; 4; pressure chamber; 5; ink conduction path; 6; nozzle; 7; common ink chamber; 8; ink supply path; 9; flexible material.

Claims (1)

[Claims] 1. A plurality of nozzles that eject ink, and a plurality of conductive paths that introduce the ink into each nozzle, respectively.
A plurality of pressure chambers through which the ink is ejected from the respective nozzles via the respective conduction paths, and a plurality of supply paths that supply the ink from the common ink chamber to the pressure chambers are arranged in one plate-like body. An inkjet recording head formed by a bored groove and further comprising a piezoelectric element disposed on the outer periphery of the pressure chamber, wherein at least a part of the supply path is a flexible member in the form of a plate. An inkjet recording head characterized in that it is constructed by covering the groove with a flexible member and pressing the flexible member against the plate member with a pressing member having a hole in a portion facing the groove.