JPH02208050A - Recording head for ink jet recorder and applying method for vibrator voltage - Google Patents

Abstract

PURPOSE:To minimize the deformation of a wall due to a rise in the inner pressure of a liquid chamber and to improve jetting efficiency by overlapping comb teeth of a vibrator by means of shifting them by every half pitch so as to form an ink channel, deforming the channel by the piezoelectric effect of the vibrator and jetting ink. CONSTITUTION:The piezoelectric vibrator 9 is bonded with a substrate A, on which grooves are made by a diamond saw. To produce a head of 8 grooves/mm, four grooves/mm are made on one side, for instance, a groove width of 90mum and a wall width of 160mum. Groove depth allows alpha (alpha is a cutting allowance of an electrode). To prevent ink from invading into the vibrator, an insulating film 7 is coated to insulate the electrode. Two substrates processed in such a way are prepared; one is turned the bottom up and both of them are joined at a wall overlapping part by shifting the difference by every half pitch. A nozzle plate 10 is bonded on the end of the substrates 3 and 8. The other end is obliquely cut to expose the electrode, and the substrates 3 and 8 are wired 12 by wire bonding or patterning to join with a driver 13.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording apparatus, and more particularly to a recording head and a vibrator voltage application method.

Japanese Patent Application Laid-Open No. 63-252750, published by Joumi Gikan, relates to a high-density multi-channel array pulsed droplet deposition device and a method for manufacturing the device. The grooves were deep compared to the previous model, making machining difficult.

■--Failure The present invention has been made to solve the above-mentioned drawbacks, and operates at a low energy level and has a large number of flow paths per unit length perpendicular to, parallel to, or both of the direction of movement of the printing paper. The purpose of this invention is to provide a recording head and a vibrator voltage application method for a multi-channel pulse droplet deposition apparatus.

In order to achieve the above object, the present invention forms an ink flow path by overlapping the comb teeth of a comb-like vibrator with a half-pitch shift, and the flow path is formed by the piezoelectric effect of the vibrator. or ejecting ink by forming a flow path with a plurality of vibrators and driving at least one vibrator, and changing the amount of flow path deformation of the plurality of vibrators. This method is characterized by selecting not to eject ink by offsetting the ink. Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a configuration diagram for explaining one embodiment of a recording head of an inkjet recording apparatus according to the present invention, and in the figure, 1
is an ink flow path, 2 is a nozzle, 3 is a substrate A, 4 and 6 are electrodes, 5 is a polarization direction of a vibrator, 7 is an insulating protective film, and 8 is a substrate B
, 9 are piezoelectric vibrators.

A piezoelectric vibrator 9 is bonded onto the substrate A. Although an adhesive or the like may be used for bonding, the method of integrally molding the substrate A and the electrode 4.6° piezoelectric vibrator 9 is known as a method of processing a laminated vibrator. Grooving is performed on this using a diamond saw as shown in Figure 1.

When making a head with 8 grooves/■, one side is machined with 4 grooves/■, so for example, the groove width is 90μ and the wall width is 160μ. The groove depth may be (groove width + α) (α is the cutting distance of the electrode), and an insulating film 7 is coated to insulate the electrode and prevent ink from seeping into the vibrator. Prepare two of the above, turn one upside down, shift the grooves by half a pitch, and join them at the overlapped part of the wall.

Figure 2 is a cross-sectional view of the recording head in Figure 1 viewed from the side.
In the figure, 10 is a nozzle plate, 11 is an ink inlet, 1
2 is a wiring, and 13 is a driver. The nozzle plate 10 is bonded to the tip of the substrate 3.8. The back side is diagonally cut to expose the electrodes, and the wiring 12 is processed by wire bonding or patterning, and connected to the driver 13.

FIGS. 3(a) to (c) are diagrams for explaining the vibrator voltage application method of the inkjet recording apparatus according to the present invention,
In the figure, a, b, and c are oscillators, and α, β, and γ are flow paths.

An electric field is applied to vibrator A and vibrator S in the same direction as the polarization direction, and an electric field is applied to vibrator C in the opposite direction to the polarization direction. That is,
In the case of polarization direction as shown in Figure 3 (,), aL-bLs
When cZ is +Ev, a, , b2 and cl are multiplied by Ov, as shown in Fig. 3(b), oscillator a and oscillator 2 are shrunk in the Y direction and extended in the X direction, and oscillator C is in the Y direction. It stretches and shrinks in the X direction.

As a result, the wall surfaces of the flow path α in three directions are narrowed, and ink is ejected. At this time, the walls of the channels β and γ on both sides of the vibrator C are expanded to suck in air, but the flow chambers are filled with ink again by slowly lowering the voltage after ink is ejected.

When the ink is not ejected from the flow path α, vibrators a and b
, c apply an electric field in the same direction as the polarization direction. That is, a,
, b, , When QL is +Ev and a, , b2, c2 is multiplied by Ov, the flow path α is narrowed by the oscillators a and b, and the flow path α is widened by the oscillator C, and the internal volumes are canceled out. Ru. In particular, if the thickness and groove width of the vibrator are approximately the same, the ratio of the X-direction displacement to the Y-direction displacement will be 1:2, and since there are two Y-direction displacements, the volume change will be approximately 0. This situation is shown in FIG. 3(c). In other words, when printing from the nozzles in the upper stage, voltage is applied to all the vibrators in the upper stage, and by changing the direction of the electric field of the vibrator just below the flow path, the ejection or pre-discharging control is controlled. The same goes for the printing of the nozzles in the lower row.

FIG. 4 is a diagram showing another embodiment of the present invention, in which 21
is a nozzle, 22.23 is an electrode, and 24 is an RTV rubber. The upper and lower walls are shaped to fit into the groove, and the space between the upper and lower channels 1 is sealed with RTV rubber 24 or the like. As a result, when the vibrator 9 is driven and shifted so as to narrow the flow path 1 from three directions, ink is ejected.

As is clear from the above explanation, according to the present invention, since the wall is thick, there is less deformation of the wall due to an increase in the internal pressure of the liquid chamber.
Discharge efficiency improves. Furthermore, since the depth of the groove is shallow, processing becomes easier and the yield is improved.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram for explaining one embodiment of a recording head of an inkjet recording apparatus according to the present invention, and FIG.
Cross-sectional view of the recording head shown in Fig. 1 viewed from the side, Fig. 3(a)
-(c) are diagrams for explaining the vibrator voltage application method of the inkjet recording apparatus according to the present invention, and FIG. 4 is a diagram showing another embodiment of the present invention. 1... Ink channel, 2... Nozzle, 3... Substrate A
. 6... Electrode, 7... Insulating protective film, 8... Substrate B,
9 electric vibrator. ４、・・・Pressure

Claims (1)

[Claims] 1. An ink flow path is formed by overlapping the comb teeth of a comb-like vibrator with a half-pitch shift, and the flow path is deformed by the piezoelectric effect of the vibrator to eject ink. A recording head for a drop-on-demand inkjet recording device featuring: 2. A flow path is formed by a plurality of vibrators, ink is ejected by driving at least one vibrator, and ink is not ejected by canceling out the amount of flow path deformation of the plurality of vibrators. A method for applying voltage to a vibrator of a drop-on-demand inkjet recording device, characterized in that: