JPS61120762A - On-demand type ink jet head - Google Patents

Abstract

PURPOSE:To reduce the area of a flexible wall of an ink pressurizing liquid chamber and facilitate integration and reduction in size of the title head, by a construction wherein the distance from an engaging point of a vibrating plate and an elastic body to a point of support of the vibrating plate by a support is set to be longer than the distance from an engaging point of the vibrating plate and a vibrator to the point of support. CONSTITUTION:When a driving pulse is impressed on an electrostrictive vibrator 19 to contract the vibrator 19 in vertical direction, the vibrating plate 18 is displaced downward with the support 17 as a fulcrum. The downward displacement of the plate 18 displaces the vibrating plate 15 downward through a vibrating rod 16, whereby the volume of the ink pressurizing liquid chamber 13 is reduced. As a result, the pressure inside the chamber 13 is raised, and an ink droplet is jetted through a nozzle 11. The vibrating plate 15 is displaced by an amount obtained by amplifying the contraction of the vibrator 19 at a ratio of the distance between the support point of the support 17 and the rod 16 to the distance between the support point to the vibrator 19, and accordingly, the strain of the vibrator 19 is amplified.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vibration unit for an ink-on-demand type inkjet head.

Previously, an ink-on-demand type inkjet head has been proposed in which an electrostrictive vibrator is attached directly to the flexible wall of the ink pressurized liquid chamber of the head (Japanese Patent Publication No. 53-45698 Publication No.

(Japanese Unexamined Patent Publication No. 57-24262).

FIG. 9 is a diagram showing such a conventional ink-on-demand type head, and FIG. 10 is a diagram showing an example in which the head shown in FIG. 9 is multi-formed. In FIG. 9 and FIG. 1θ, 1 is a nozzle, 2 is an ink channel on the nozzle side, 3 is an ink pressurizing liquid chamber, 4 is an ink supply channel, 5 is a substrate, and 6 is an upper plate. forms a flexible wall of the ink pressurized liquid chamber, to which the electrostrictive vibrator 7 is directly attached. 8 is an ink supply pipe, 9 is an ink supply common liquid chamber, and 10 is an ink supply hole.

To explain the ink ejecting operation of the above conventional head, the ink supplied to the ink pressurized liquid chamber 3 through the ink supply pipe 8 is distorted by the electrostrictive vibrator 7 according to the print signal.
As a result, the upper plate 6 is bent, the volume of the ink pressurized liquid chamber 3 is reduced, the pressure is increased, and ink is ejected from the nozzle l.

However, in this type of head, since the electrostrictive vibrator is directly attached to the flexible wall, the vibrator is difficult to displace, and the vibrator cannot be made small.

As a result, the area of the flexible wall of the ink pressurized liquid chamber cannot be made small, which poses a problem in terms of miniaturization and integration of the head.

The present invention has been made in view of the above circumstances, and has the purpose of making it possible to reduce the area of the flexible wall of the ink pressurizing liquid chamber, thereby facilitating the integration and miniaturization of the head. It has been done.

In order to achieve the above-mentioned object, the present invention forms at least a part of the wall of the ink pressurized liquid chamber with an elastic material, and has vibrations that are supported by a support and excited by engaging with a vibrator. In an on-demand inkjet nozzle that ejects ink droplets by changing the volume of the pressurized ink chamber by engaging one end of the plate with the elastic body, the engagement point between the diaphragm and the elastic body is , the length between the supporting body and the support point of the diaphragm is longer than the length between the engagement point of the diaphragm and the vibrator and the support point. Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a diagram showing an embodiment of an on-demand inkjet head according to the present invention, and FIG. 2 is a diagram showing an example in which the head in FIG. An ink flow path, 13 is an ink pressurizing liquid chamber, 14 is an ink supply side flow path, 15 is a diaphragm made of an elastic body forming a part of the wall of the ink pressurizing liquid chamber, and a rigid vibrating rod 16
It engages with the diaphragm 18 via. The vibration rod 16 does not necessarily have to be rod-shaped, and may be a convex body provided on the vibration plate 15 or 18. The diaphragm 18 is formed of an elastic body (a rigid body may be elastic in shape) made of stainless steel, phosphor bronze, glass, plastic, etc.; It is supported by a support 17 (which may be an elastic body as long as it is rigid), and an electrostrictive vibrator 19 is attached thereto.

Next, the operation of the head will be explained. First, the electrostrictive vibrator 19
When a driving pulse is applied to the diaphragm 18 to cause the diaphragm 18 to contract in the vertical direction, the diaphragm 18 is displaced downward using the support 17 as a fulcrum. The downward displacement of the diaphragm 18 is caused by the diaphragm 15 via the diaphragm 16.
is displaced downward to reduce the volume of the ink pressurized liquid chamber 13. This increases the internal pressure of the ink pressurized liquid chamber 13, and ink droplets are ejected from the nozzle 11. Incidentally, the displacement of the diaphragm 15 is determined by the ratio of the length between the support point of the support body 17 and the vibration rod 16 and the length between the support point and the electrostrictive vibrator 19. The amount of shrinkage is amplified. That is, the amount of strain in the electrostrictive vibrator is amplified by the principle of leverage.

FIG. 3 is a perspective view of the vibration unit section of the head shown in FIG. 1.

FIG. 4 shows another embodiment of the diaphragm of the vibration unit section of FIG. When attaching the electrostrictive vibrator 19, this is an escape hole for absorbing variations in the length direction, and the vibrating rod and the electrostrictive vibrator are bonded at this hole by adhesive or the like.

FIG. 5 shows an example of a lead pattern 32 for feeding power to the electrostrictive vibrator 19 attached to the substrate 21 of the vibrating unit-nod of the present invention, and the other end of the electrostrictive vibrator 19 is connected to an integral part (not shown). Since it is connected to a comb-teeth shaped diaphragm, a current flows through the diaphragm.

FIG. 6 shows an example of an integrated diaphragm, and 17 is a support.

FIG. 7 shows another embodiment of the vibration unit of the present invention, (
A) is a side view, and (B) is a perspective view.

In this example, the electrostrictive vibrator 19 is provided on the opposite side of the support body 17 from the vibrating rod 16, and the direction of displacement of the vibrator 19 and the direction of displacement of the vibrating rod 16 are opposite to each other. Similar to the vibration unit shown in FIG. It is determined by the ratio. Note that the support body 17 is made of an elastic member that can easily bend around the joint with the substrate 11, and is
is a rigid body.

Figure 8 shows an electrostrictive vibrator used in the invention. (A) is a round rod shape, (B) and (C) are prismatic shapes, but they are not limited to these, and can be any type that is displaced by the application of voltage. Moreover, the electrode 40 to which voltage is applied does not necessarily have to coincide with the displacement direction. For example, if a voltage is applied in the thickness direction in the same figure (C), it will expand and contract in the thickness direction, but it will also expand and contract in the longitudinal direction perpendicular to the thickness direction, opposite to the thickness direction, and this can be utilized.

Also, not only electrostrictive vibrators, but also magnetostrictive vibrators? An S element bimetal or the like may be used as the displacement source.

As described above, according to the present invention, the amount of displacement of the vibrator is amplified by the principle of leverage, so in order to obtain a predetermined volume change (reduction) of the ink pressurized liquid chamber of the head, the amount of displacement of the vibrator and the ink can be increased. The pressurized liquid chamber can be made smaller, and the head can be made smaller and more integrated.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the on-demand inkjet nozzle according to the present invention, FIG. 2 is a diagram showing an example in which the head shown in FIG. 1 is multi-layered, and FIG. 3 is a diagram showing the head shown in FIG. FIG. 4 is a diagram showing another embodiment of the vibration plate of the vibration unit part of FIG. 3, and FIG. 5 is a diagram showing an example of the lead pattern of the substrate of the vibration unit of the present invention. ,
FIG. 6 is a diagram showing an example of an integrated diaphragm, FIG. 7 is a diagram showing another embodiment of the vibration unit of the present invention, FIG. 8 is a diagram showing an electrostrictive vibrator used in the present invention, and FIG. FIG. 9 is a diagram showing a conventional ink-on-demand type head, and FIG. 10 is a diagram showing an example in which the head of the type shown in FIG. 9 is multi-layered. 11... Nozzle, 12... Ink channel, 13...
Ink pressurized liquid chamber, 14... channel, 15... imaging plate,
16... Vibration rod, 17... Support plate, 18... Vibration plate, 19... Electrostrictive vibrator, 20... Ink supply tube. Figure 111\&2 Figure M3 Figure 6 Figure 7 (A) (B) Figure 8 (A) Figure 9 Figure 10

Claims (1)

[Claims] By forming at least a part of the wall of the ink pressurized liquid chamber with an elastic body, and engaging one end of a diaphragm supported by a support body and excited by engaging with a vibrator with the elastic body, In an on-demand inkjet head that ejects ink droplets by changing the volume of an ink pressurized liquid chamber, the length between the engagement point of the diaphragm and the elastic body and the support point of the diaphragm by the support body, An on-demand inkjet head characterized in that the length is longer than the length between the engagement point of the diaphragm and the vibrator and the support point.