JPS61173948A - Cantilevered beam vibration unit type ink jet head - Google Patents

Abstract

PURPOSE:To reduce and obstruct the residual vibration of a vibration unit, by providing a vibration unit part acting on an ink pressurizing liquid chamber and a vibration unit part protruded to the opposite side from a support point. CONSTITUTION:When a signal pulse P0 is inputted to a monomultivibrator 21 and a high voltage amplifier 26, the pulse P1 amplified by the high voltage amplifier 26 is applied to the electrode 1001 of a cantilevered beam vibration unit formed of electrodes 1001, 101, an electrostriction vibrator 102, a common electrode 103 and a vibration plate 104. This pulse P1 is applied between the common electrode 103 and the electrode 1001 and the vibration unit is bent downwardly from a support stand 9 being a fulcrum and ink is pressurized by a connection rod 10 and a diaphragm 11 to emit ink droplets. The pulse P0 operates monomultivibrators 21, 22 to generate output MM2S. The output MM2S is amplified by a high voltage amplifier 27 to be converted to a pulse P2 which is, in turn, applied between the electrode 101 and the common electrode 103 and acts so as to reduce and obstruct the residual vibration of the vibration unit.

Description

[Detailed Description of the Invention] Kokemame! The present invention relates to a cantilever vibrating unit type inkjet head, and more particularly to a technique for reducing and preventing residual vibration of a cantilever vibrating unit in an on-demand inkjet recording device.

Prior art Fig. 5 is a sectional view showing an example of a conventional on-demand inkjet head, in which 1 is a nozzle, 2 is an ink flow path, 3 is an electrostrictive vibrator unit, and 4 is an ink pressurizing liquid chamber. ,
5 is a head upper plate, 6 is a head substrate, 7 is an ink channel, 8
is an ink supply pipe, and as shown in the figure, an electrostrictive vibrator unit 3 is tightly joined to the flexible wall of the pressurized ink liquid chamber 4, and this vibration unit 3 is distorted in accordance with a signal pulse to supply the pressurized ink liquid. Ink droplets are ejected from the nozzle 1 by reducing the volume of the chamber 4, but a head with such a configuration has the disadvantage that residual vibration occurs in the vibration unit even after the signal pulse disappears, resulting in a decrease in the response frequency. was there.

FIG. 6 is a sectional view showing another example of a conventional inkjet head, in which 9 is a vibrator unit support, 10 is a connecting rod, 11 is a flexible wall (diaphragm), and 5
Parts which act in the same way as in the figure are given the same reference numerals as in FIG. 5.

As shown in the figure, this inkjet head has
The vibration unit 3 is of a cantilever type, and one end is fixed to the support stand 9, and the other end is connected to the flexible wall 11 of the ink pressurized liquid chamber 4 via the connecting rod 10. In this case as well, the vibration unit vibrates at its natural frequency, and even if the drive pulse disappears, residual vibration will occur in the vibration unit, and this residual vibration may cause the satellite droplet to be ejected or be generated by the next pulse. This has the disadvantage of affecting pressure waves and causing deterioration of droplet ejection frequency characteristics.

FIG. 7 is a diagram for explaining an example of an inkjet head drive circuit designed to prevent residual vibrations as described above, and FIG. 8 is a time chart for explaining its operation. 23 is a mono multivibrator,
When the signal pulse P enters the mono multivibrator 21.22, the output MM from each mono multivibrator
1s, MM2. s, MMls turns on the transistor 24 and drives the vibrator unit 3. The output MM1s of this mono-multivibrator 21 is a main pulse (or first pulse), and the pulse width of this main pulse MM1s is set to an arbitrary predetermined value. On the other hand, after the output MMzs of the mono multivibrator 22 is generated for a predetermined time, the mono multivibrator 23 is operated to generate its output MM3s. This output M M 3 s turns on the transistor 25 and applies a voltage to the vibrator unit 3 . This output M M 3 S is the slave pulse (
(second pulse), and acts to reduce residual vibration of the vibrating uni-throat caused by the main pulse (first pulse).

When the residual vibration of the vibration unit is canceled out by applying the second pulse as described above, when the head is configured with multiple nozzles, the second pulse is applied to each of the vibration units corresponding to each nozzle. It is necessary to configure a drive circuit so as to apply , which has the disadvantage of increasing costs.

The present invention was made in view of the above-mentioned circumstances.
In particular, in view of the fact that the residual vibration of the vibration unit for ejecting ink droplets in ink-on-demand inkjet heads has a negative effect on droplet ejection, this was developed with the aim of reducing or preventing the residual vibration of the vibration unit. be.

In order to achieve the above object, the present invention provides an inkjet head that has a cantilever-supported vibration unit and that uses the vibration unit to reduce the volume of the ink pressurized liquid chamber of the inkjet head to eject ink droplets. The vibration unit is characterized in that it has a vibration unit portion that extends from the support point and acts on the ink pressurized liquid chamber, and a vibration unit portion that projects from the support point to the opposite side. Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a block diagram of main parts for explaining one embodiment of the present invention, FIG. 2 is a block diagram of main parts showing an example of applying the present invention to a multi-nozzle head, and FIG. FIG. 4, a time chart for explaining the operation of the present invention, is a detailed circuit diagram of the high voltage amplifiers 26 and 27 shown in FIG. 1, and 28 is an electrostrictive vibrator. Now, when the signal pulse PO is input to the monomulti-by-break 21 and the high voltage amplifier 26, the pulse P1 amplified by the high voltage amplifier 26 is transmitted to the electrode L00.
1.101. Electrostrictive vibrator 102. Electrode 10 of a cantilever vibration unit consisting of a common electrode 103 and a diaphragm 104
01. In this cantilever beam vibration unit, the electrodes of the vibrator are separated between the actuator side for ejecting ink droplets connected to the connecting rod and the overhang side, and the electrode 1001
and 101. Then, the pulse P1 is applied between the common electric rod 103 and the electrode 1001, so that the vibration unit uses the support base 9 as a fulcrum and the electrode 100
The first side bends downward. This operation is performed by connecting rod 10
The pressure is transmitted to the diaphragm 11 via the ink pressurizing liquid chamber of the head, and the ink in the ink pressurizing liquid chamber of the head is pressurized to eject ink droplets.

On the other hand, the pulse Po operates the mono multi-pipe lake 21, and the mono multi-pipe lake 21 outputs M M
1 s to operate the mono multivibrator 22. Monomultipipe rake 22 generates an output MMλS. MMZ3 is amplified by the high voltage amplifier 27 to become a pulse P2, which is applied between the electrode 101 of the vibrating unit and the common electrode 103, and acts to reduce the residual vibration of the vibrating unit caused by the pulse P1.

FIG. 2 shows an example of an integrated (comb-shaped) cantilever vibrating unit of a multi-nozzle head. ~1004 are separated.

As is clear from the above description, the present invention is effective when applied to a cantilever vibrating unit type ink-on-demand head. That is, as shown in FIG. 1, the vibration unit of the cantilever vibration unit type ink-on-demand head is made to project from the side opposite to the side where it is connected to the connecting rod IO, with the support base 9 as a border, and the projecting portion is The electrode of the electrostrictive vibrator is provided separately from the electrode of the electrostrictive vibrator connected to the connecting rod 10, and a second pulse is applied to this electrode at a predetermined timing in response to the pulse for ejecting ink droplets. By applying this, residual vibration of the vibration unit caused by the ink droplet ejection pulse can be reduced. Further, in the integrated cantilever vibrating unit in the same type of multi-nozzle head, the above-mentioned overhanging portion can be provided in common, and if a common second pulse is applied to the electrode of this overhanging portion, The residual vibration of each vibration unit corresponding to each nozzle can be reduced, and the residual vibration of the vibration unit in a multi-nozzle head can be reduced easily and inexpensively.

[Brief explanation of drawings]

FIG. 1 is a block diagram of main parts for explaining one embodiment of the present invention, FIG. 2 is a block diagram of main parts showing an example of the case where the present invention is applied to a multi-nozzle head, and FIG. A time chart for explaining the operation of the present invention, FIG. 4 is a detailed circuit diagram of the high voltage amplifier shown in FIG. 1, and FIGS. 5 and 6 are:
FIG. 7 is a side cross-sectional configuration diagram for explaining an example of a conventional inkjet head, FIG. 7 is a diagram showing an example of a conventional inkjet head drive circuit, and FIG. 8 is a time chart for explaining its operation. . 1... Nozzle, 3... Vibration unit, 9... Support stand. 10.101-104...Connection rod, 11...Flexible wall. 21~23... Mono multivibrator, 26°27
...High voltage amplifier, 10 (h~1004, 101°103... Electrode, 102... Electrostrictive vibrator, 1o4.
...Vibration plate. Figure 3 Figure 5 → b Figure 6 Figure 7

Claims (3)

[Claims] (1) In an inkjet head having a cantilever-supported vibration unit, the vibration unit reduces the volume of an ink pressurized liquid chamber of the inkjet head to eject ink droplets, wherein the vibration unit is supported by a support. a vibration unit portion extending from the point and acting on the ink pressurizing liquid chamber;
A cantilever vibrating unit type inkjet head, characterized in that it has a vibrating unit portion projecting to the opposite side from the support point. (2) The vibration unit has an electrostrictive vibrator and a pair of electrostrictive vibrator electrodes that sandwich the electrostrictive vibrator, and at least one of the electrostrictive vibrator electrodes is connected to the supporting point as a border. The cantilever vibration unit type inkjet head according to claim 1, wherein the inkjet head is separated. (3) The cantilever beam according to claim (2), further comprising pulse generating means for applying a second pulse to the electrostrictive vibrator electrode on the protruding portion of the vibration unit. Vibration unit type inkjet head.