JPH03216338A - inkjet recording device - Google Patents

Abstract

PURPOSE:To obtain optimum particles, improve a response frequency, and realize a halftone expression in an easy manner by a method wherein a piezoelectric element provided in the longitudinal direction of a parallel flow path is divided into a plurality of parts, and a circuit for independently driving each of the piezoelectric element parts is provided. CONSTITUTION:A piezoelectric element 22 extending in the longitudinal direction of a flow path is bonded on a substrate 21 in a divided state. One piezoelectric element is provided with an A part creeped through the end part thereof as a GND electrode and a B part similarly creeped through the end part thereof as a signal line. The other piezoelectric element is provided with a C part as a GND electrode and a D part as a signal line. A time lag is provided between an actuator consisting of the A - B part near a nozzle and an actuator consisting of the C - D part. A transmitting time lag between a pressure wave generated in the C - D part and a pressure wave generated in the A - B part is eliminated. For realizing a halftone expression, a delivery volume is changed by changing the number of actuators to be driven.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an inkjet recording device, and more particularly to an eight-note section of an inkjet recording device.

Publicly known documents related to the present invention include the following. JP-A No. 60-90770 discloses that a piezoelectric element is provided on a diaphragm and held rigidly. A head made of a rigid member is disclosed, and by using deformation due to the piezoelectric strain constant perpendicular to the polarization direction instead of deformation due to the piezoelectric strain constant perpendicular to the polarization direction, pressurizing chambers can be arranged in high density, and electrical This facilitates physical connection.

However, in the above system, when one actuator moves, it affects the adjacent actuators, and the adjacent actuators are connected through the diaphragm, and the flow path is also connected to the diaphragm. Because of this, there was a drawback that the influence on adjacent actuators was unavoidable.

In addition, in the previously proposed patent application No. 1-138503, there is a filler between the slits, so when one is folded through this, the filler moves along with it, and the flow name plate that is joined also moves. There was the inconvenience of moving together.

In this way, in the conventional example, in response to a long flow path,
There was one piezoelectric (PZT) actuator section, and a corresponding nozzle was provided.

In order to increase the discharge volume and increase the degree of accumulation with such a long flow path. The longer it is, the smaller the displacement of the actuator will be.
It becomes possible to drive at low voltage and reduce costs. However, a drawback of a long flow path is that there is a delay in vibration propagation through the fluid, so it is not possible to make the flow path as long as you want and reduce the amount of actuator displacement. As a phenomenon caused by the delay in propagation, when particles are formed, cutting during droplet formation is not performed optimally, resulting in the formation of many satellites and trailing. The liquid that adheres to the recording paper due to this phenomenon is
The image appears as an ellipse or as a horizontally long line. Image quality will be degraded. This becomes even more noticeable when the printing speed increases (that is, in the case of a serial printer that is mounted on a carriage and scans heads).

Furthermore, displacement occurs in the actuator in response to high frequencies.

However, since the acting fluid causes a response delay in propagation, there is a limit to increasing the speed. Furthermore, when changing the ejection amount and modulating the pixel diameter, the conventional method is to set the activation voltage in stages and change the displacement amount, which makes the circuit complicated and increases the cost. was.

FIG. 5 shows a side sectional view of a head section of a conventional inkjet printing apparatus. In the figure, 31 is a substrate, 32 is a piezoelectric element (PZT). 33 is a channel plate, 34 is a liquid chamber, 35 is an ink supply pipe, 36 is a nozzle plate, 37 is a bonding wire, 38 is a lead wire, 39 is an electrode, 40 is a common liquid chamber, and 41 is a wiring plate. Conventionally, the signal line was connected to the wiring plate 41 from the rear end using a welding bonder, etc.
Connect and take out. Further, the common GND line is commonly connected to the substrate 31 from the bottom surface of the piezoelectric element 32.

Stop 4 The present invention was made in view of the above-mentioned circumstances, and
The purpose of this invention is to provide an inkjet recording device that optimizes particle formation caused by a delay in the propagation speed of liquid, improves response frequency, and facilitates halftone reproduction.

In order to achieve the above object, the present invention provides a piezoelectric body with slits, a protrusion formed between the slits as an actuator, a parallel flow path corresponding to the protrusion, By causing a thickness displacement in a direction perpendicular to the plane of the parallel flow path,
In an inkjet recording device that ejects droplets, the piezoelectric body provided in the longitudinal direction of the parallel flow path is divided into a plurality of parts, each piezoelectric body is moved independently, and the piezoelectric body is moved independently. It is characterized by having a circuit that performs the following steps. Hereinafter, the present invention will be explained based on examples.

FIG. 3 is a diagram schematically showing a head section of an inkjet recording apparatus according to the present invention. In the figure, 1 is a substrate, 2 is a piezoelectric element (PZT). 3 is a channel plate, 4 is a liquid chamber, 5 is an ink supply pipe, 6 is a nozzle plate 1, 7 is a copper wire, 8 is a lead wire, 9 is an electrode, 10 is a ground wire, and 11 is a wiring plate. be.

A channel plate 3 and a substrate 1 are disposed to sandwich a piezoelectric element 2, and a nozzle plate 6 and a liquid chamber 4 are provided in the longitudinal direction.

Figure 4 is an enlarged view of part ■ in Figure 3. In the figure, 3a is an ink flow path, 12 is a filler, 13 is ink, 14 is an electrode, and other parts that have the same function as in Figure 3 are the same. Reference numbers are given. The piezoelectric element (PzT) 2 is grooved so that it can sleep independently, and the convex portion formed by the groove changes in thickness to create a corresponding channel 3 in the channel plate 3.
The volume of a changes, and ink 13 is ejected from the nozzle. Also. The groove portion is filled with a filler 12 so as not to be influenced by adjacent actuators. Figures 3 and 4
In the example shown in the figure, a laminated type piezoelectric element is presented, but a single layer structure is also applicable.

FIG. 1 is a configuration diagram for explaining one embodiment of an inkjet recording apparatus according to the present invention, in which 15 is an ink supply vibrator, 16 is a nozzle plate, 17 is a copper wire, 18 is a lead wire,]9 is an electrode, 20 is an insulating material, 21 is a substrate, 2
2 is a piezoelectric element (pzT), 23 is a channel plate, 24 is a liquid chamber,
25 is a wiring plate.

A piezoelectric element 22 extending in the longitudinal direction of the flow path is divided and bonded on the substrate 21. In the embodiment of the present invention, a case in which the device is divided into two is shown, but the same applies to cases in which the device is divided into two. First, it has a part A where the end of the piezoelectric element is passed around as one GND electrode, and a part B where the end part of the piezoelectric element is passed around as a signal line. Next, the other piezoelectric element uses the C part as a GND electrode and the D part as a signal line, like the piezoelectric element described above.

FIG. 2 shows a signal extraction pattern using electrodes arranged on the substrate 21. The parts A to C correspond to those in FIG. The A section is connected to the GND electrode from the C section, and the outside is wired all together to take out a common GND line. Portion B is connected as a signal line from the substrate to the wiring plate 25 by bonding. Further, in the D section, the piezoelectric element is directly bonded to the wiring plate.

One method for manufacturing these devices is to bond a single piezoelectric element patterned in advance onto a substrate, and then use dicing to create grooves along the width of the actuator so that it can be moved independently. After that, it can be easily manufactured by dicing in the longitudinal direction. Moreover, patterning and wiring can be easily carried out on silicon, ceramic, or glass as a substrate, and rigidity as a substrate can be obtained.

The longitudinally divided portions described above are filled with an insulating material to suppress electrical discharge between the electrodes. However, in this case, it is preferable to use a rigid actuator with some degree of elasticity so as not to interfere with other actuators when the actuator moves independently.

Next, there are the following methods of rotation.

1゛・Delayed rotation: A time difference is set between the actuator formed by parts A and B near the nozzle and the actuator formed by parts C and D, so that the pressure waves generated in part C and D are Eliminate the propagation time difference of pressure waves generated in part 1B.

3.Individual adjustment: The effect of changing the discharge volume by changing the number of sliding actuators to express halftones.As is clear from the above explanation, according to the present invention, the actuators are divided By making a structure and moving each part independently, droplet formation is stabilized, image quality is improved, high-frequency response is achieved, and high speed is possible.■ Discharge volume can be controlled, and intermediate This has the effect of making tonal expression possible.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram for explaining one embodiment of an inkjet recording device according to the present invention, FIG. 2 is a diagram showing an electrode pattern arranged on a substrate, and FIG. 3 is a diagram showing an example of an inkjet recording device. A diagram schematically showing the head section, FIG.
FIG. 5, which is an enlarged view of part (■) in the figure, is a side sectional view of the hent part of a conventional inkjet recording apparatus. 15-・Ink supply vibrator, 16・Nozzle plate, l
7. Copper wire, 18. Riet wire, 19. Electrode, 20. Insulating material, 21. Substrate. 22-pzr, 23 channel plate, 2,1
Liquid chamber, 25 Wiring plate, Fig. 1 Convex Fig. 2 A

Claims (1)

[Claims] 1. A slit is provided in the piezoelectric body, a convex portion formed between the slits is used as an actuator, a parallel flow path is provided corresponding to the convex portion, and a thickness displacement is caused in a direction perpendicular to the plane of the parallel flow path. Accordingly, in an inkjet recording device that ejects droplets, the piezoelectric body provided in the longitudinal direction of the parallel flow path is divided into a plurality of parts, each piezoelectric body is driven independently, and the piezoelectric body is independently driven. An inkjet recording device characterized by having a circuit driven by an inkjet recording device.