JPH03187754A - inkjet head - Google Patents

Abstract

PURPOSE:To make decrease of an ink quantity caused by feed resistance not caused without necessity for controlling a relative position in an ink discharge opening direction by a method wherein an ink discharge opening is almost slit-like, and one ink discharge opening faces a plurality of vibrators. CONSTITUTION:A platy substrate 22 having a base material 25, a vibrator 21, a spacer 23, and an ink discharge opening 24 constructs a transducer unit by being unified, and a wiring 27 is provided thereto. An ink discharge opening 24 provided on the platy substrate 22 is of a slit like form extending in a direction conforming to an arranging direction of a vibrator 21. When voltage is impressed between an electrode layer 33 and a metallic layer 34 via the wiring 27, a piezoelectric material layer 35 is contracted and besides, the metallic layer 34 is not contracted. Therefore, a bending moment is generated, and a free end tip of the vibrator 21 is displaced in a direction going far from the platy substrate 22. When voltage is released, it displaces by restoring force of the vibrator 12, and ink is discharged from the ink discharge opening 24 by pressure to be generated. Since the ink discharge opening is of a slit like form, manufacture becomes easy without necessity for controlling a relative position, and decrease of an ink quantity is not generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inkjet recording device such as a printer that flies ink droplets to form an ink image on a medium such as recording paper, and more specifically relates to an inkjet recording device such as a printer that forms an ink image on a medium such as a recording paper. The present invention relates to an inkjet head used.

[Conventional technology]

A known structure of a conventional inkjet head is that a plate-like member having a plurality of ink discharge openings is provided with a beam-like vibrator made of a piezoelectric transducer in one-to-one correspondence with the ink discharge openings. 6O-8953).

[Problem to be solved by the invention]

In the structure of the conventional inkjet head described above, the relative positional accuracy of the vibrator and the ink ejection opening affects the ejection characteristics, so it is necessary to control this with precision. It was difficult to arrange the density. Furthermore, since the gap between the member forming the nozzle and the vibrator affects the generated pressure, it has to be controlled with high precision to a minute value of about several tens of microns. Since the ejected ink passes through this gap and reaches the nozzle, the amount of ejected ink decreases when driven at a high frequency due to fluid resistance in this part. For this reason, there have been problems in that print quality deteriorates and high viscosity ink cannot be used.

An object of the present invention is to solve these problems and realize an inkjet head that is easy to manufacture and has high print quality.

[Means to solve the problem]

The inkjet head of the present invention has a plurality of vibrators that face a plate-like substrate having ink ejection openings and can be driven and controlled independently, and ejects the ink interposed between the vibrators and the plate-like substrate. In an inkjet head that discharges ink from an opening, the ink discharge opening is generally slit-shaped, and one ink discharge opening is configured to face a plurality of vibrators.

[Effect]

In the above configuration of the present invention, since the ink ejection opening is in the shape of a long slit in the direction in which the vibrators are arranged, there is no need to manage the relative position in this direction, and ink that is held by capillary force is ejected into the slit portion. Therefore, the amount of ink does not decrease due to supply resistance.

〔Example〕

Next, the present invention will be explained based on examples.

FIG. 1 is a perspective view of a printer showing an embodiment of the present invention. In the figure, recording paper 10 is wound around a platen 11 and is pressed by feed rollers 12 and 13. The inkjet head 16 is mounted on a carriage 15 that is guided by guide shafts 14 and 17 and movable in a direction parallel to the platen axis. The inkjet head 16 has a plurality of electromechanical transducers that can independently control the ejection of ink droplets, and selectively ejects ink droplets from the ink ejection openings by scanning in the platen axis direction to form an ink image on the recording paper 10. . The recording paper 10 is conveyed in the sub-scanning direction perpendicular to the scanning direction by rotation of the platen 11 and feed rollers 12 and 13, and printing is performed on the recording paper surface.

FIG. 2 shows a cross section of an inkjet head showing an embodiment of the present invention. Base material 25, vibrator 21, spacer 2
3. The plate-shaped substrate 22 having the ink ejection openings 24 is fixed in advance and formed into a unit to constitute the converter unit 31, and the wiring 27 is further provided. The plate-like substrate 22 and spacer 23 of the converter unit 31 are attached using pins 46 and 47. Since one of the holes on the plate-like substrate 22 corresponding to the bins 46 and 47 is an oblong hole 48, it is positioned at one end with reference to the hole 49. Furthermore, ink 26 is supplied into the head and fills the space 28 between the plate-shaped base plate 22 and the vibrator 210.

The vibrator 21 has a piezoelectric material layer 35 made of PZT with Au on one side.
It has a multilayer structure including an electrode layer 33 made of a thin layer and a metal layer 34 made of a thin Ni layer on the opposite side.

FIGS. 3(a) and 3(b) show the configuration of the converter unit 31 and its peripheral parts. The same members as in FIG. 2 are given the same numbers. FIG. 3(a) shows the manufacturing process. The multilayer plate 40, base material 25, and spacer 23 constituting the above-mentioned vibrator 21 are joined together with an adhesive or the like. Then Figure 3(b)
As shown in FIG. 3, a plurality of grooves 41 are formed by dicing to form each vibrator 42, thereby forming a plurality of vibrators that can be driven independently. By making the groove 41 deep enough to reach the base material 25, a plurality of cantilever-shaped vibrators without mutual interference can be formed. The base material 25 is an insulator (glass, ceramic, etc.) having an electrode pattern 43 on its upper surface for electrical connection.

Further, wiring 2 of the flexible substrate has a wiring pattern corresponding to a position facing the electrode pattern 43 on the base material as shown in FIG. 2 for connection with an external drive circuit.
7 is joined. Electrodes for keeping each vibrator 21 at a common potential are electrically connected and wired when bonding the spacer 23 to the surface of the metal layer 34 opposite to the above-mentioned surface. The ink discharge opening 24 provided on the plate-like substrate 22 is connected to the vibrator 21.
It has a slit-like shape extending in a direction that coincides with the arrangement direction.

Next, a structure for incorporating the transducer unit 31 and its peripheral members into the head body will be explained using FIG. 3 and FIG. 2. The converter unit 31 is positioned with respect to the head frame 20 by one positioning pin (not shown) set up on the head frame 20 and a hole 44, and is fixed by being screwed with a screw 32 using another hole 45.

Next, the operation will be explained. By applying a voltage between the electrode layer 33 and the metal layer 34 formed on both sides of the vibrator 21 via the wiring 27, the piezoelectric material layer 35 between them contracts, while the metal layer 34 does not contract, so a bending moment is generated. This occurs, and the tip of the free end of the vibrator 21 is displaced in the direction away from the plate-shaped substrate 22. Next, when this voltage is released, the vibrator 21 is displaced by the elastic restoring force, and ink is ejected from the ink ejection opening 24 due to the generated pressure.

〔Effect of the invention〕

As described above, according to the above structure of the present invention, since the ink ejection opening is in the form of a long slit in the direction in which the mechanical and electrical transducers are arranged, there is no need to manage the relative position in this direction, which facilitates manufacturing. have Further, since the ink held in the slit portion is ejected, a decrease in the amount of ink due to supply resistance does not occur. This has the effect of enabling high frequency driving. In addition, since multiple circular nozzles with minute diameters are not used, it is easy to manufacture the components that form the nozzles, and it is also possible to measure the dimensions between this component and the vibrator using, for example, an optical method. This also makes manufacturing easier.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a printer equipped with an inkjet head showing one embodiment of the present invention. FIG. 2 is a sectional view of an inkjet head showing an embodiment of the present invention. FIG. 3(a) is a perspective view showing the manufacturing process of the peripheral part of the piezoelectric transducer of an inkjet head showing one embodiment of the present invention, and FIG. 3(b) is a perspective view of the transducer unit. 16 Inkjet head 21.42 Vibrator 22 Plate substrate 24 Ink discharge opening 25 Paste material 26 Ink 31 Converter unit or above

Claims (1)

[Claims] An inkjet head that has a plurality of vibrators that face a plate-like substrate having an ink discharge opening and that can be independently driven and controlled, and that discharges ink interposed between the vibrators and the plate-like substrate from the ink discharge opening. An ink jet head characterized in that the ink discharge opening is generally slit-shaped and configured such that one ink discharge opening faces a plurality of vibrators.