JPH03216339A - Ink jet recorder - Google Patents

Abstract

PURPOSE:To improve an image quality and enhance an effective drive frequency by fitting the projected part of an actuator into the recessed part of a parallel flow path out of contact with each other. CONSTITUTION:In the construction wherein flow paths 24 of a flow path plate 23 are nested with actuators 22, 27 out of contact with each other, the actuator 27 can compress and deliver a liquid in the flow paths 24 without interfering with the adjacent actuator when the actuator 27 is driven. A piezoelectric element 2 is grooved to allow the actuator to be independently driven. The projected parts formed by the grooves are displaced in thickness, whereby flow paths 3a provided in a flow path plate 3 correspondingly thereto are changed in volume to deliver ink 13 out of nozzles. The groove parts are filled with a filler 21 to prevent the interference with the adjacent actuator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inkjet recording apparatus, and more particularly to a head section of an inkjet recording apparatus.

Publicly known documents describing the prior art related to the present invention include the following. Japanese Unexamined Patent Publication No. 60-90770 discloses a head made of a rigid member in which a piezoelectric element is provided on a diaphragm and held rigidly, and instead of deformation due to a piezoelectric strain constant perpendicular to the polarization direction, By using deformation due to the same piezoelectric strain constant as , it is possible to arrange the pressurizing chambers in a high density and facilitate electrical connection.

However, in the above system, when one actuator moves, it affects the adjacent actuators, and the adjacent actuators are connected via a diaphragm, and the flow path also has a diaphragm. Since the actuator is connected to the actuator, it has the disadvantage that the influence on the adjacent actuator cannot be avoided.

In addition, in the previously proposed patent application No. 1-138503, there is a filler between the slits, so when one of the slits is driven through this filler, the filler also moves with the slit, causing the bonded flow to flow. There was an inconvenience that the road plates also moved together.

As described above, due to the drawbacks seen in the conventional method, when several adjacent pixels are moved simultaneously, each of them influences each other, making it impossible to obtain uniform ejection, which causes the adjacent pixel diameters to differ, resulting in a decrease in image quality. It became. Moreover, if this is driven at a distance that is not affected in order to improve this, the actual printing frequency will be slowed down, and the printing speed will be reduced.

Purpose The present invention was made in view of the above-mentioned circumstances.
The purpose of this invention is to provide an inkjet recording device that can be moved without affecting adjacent actuators, thereby improving image quality and increasing the effective floating frequency. .

In order to achieve the above-mentioned object, the present invention provides (1) slits in a piezoelectric body, a convex portion formed between the slits as an actuator, and a parallel flow path corresponding to the convex portion. is established,
In an inkjet recording device that ejects droplets from a nozzle by causing a thickness displacement in a direction perpendicular to a surface of the flow path, the convex portion of the actuator and the recessed portion of the parallel flow path fit together without contacting each other. , furthermore, (2
) the actuator is coated with an insulator;
Furthermore, (3) the slit portion of the actuator is filled with an insulating material without contacting each other. Hereinafter, the present invention will be explained based on examples.

FIG. 2 is a diagram schematically showing the head section of the inkjet recording apparatus according to the present invention. In the figure, ■ 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, 7 is a copper wire, 8 is a lead wire,
9 is an electrode, 10 is a grounding lead wire, and 11 is a wiring plate.

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 3 is an enlarged view of part ■ in Figure 2. 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 2 are the same. Reference numbers are given. The piezoelectric element (PZT) 2 is grooved so that it can be moved independently. As the thickness of the convex portion formed by this changes, the volume of the correspondingly provided channel 3a in the channel plate 3 changes, and the ink 13 is ejected from the nozzle.

Further, the groove portion is filled with a filler 12 so as not to affect adjacent actuators. In the examples shown in FIGS. 2 and 3, a laminated type piezoelectric element was presented, but
The same applies to a single layer structure.

FIGS. 4(a) to 4(c) show an example of the deformation of the flow path during driving when a filler is used.

■Explanation of Figure (b) when only piezoelectric element A is driven from Figure (a) which is the initial state.

The partition wall (SE, S3-84) deforms in the direction of decreasing volume, but the partition wall (S2) deforms in the direction of expansion, and the actual discharge amount ΔSA1 becomes as follows.

ΔSA■=(S1+S3+S4)-82■ Explanation of Figure (C) when piezoelectric elements A, B, and C are driven from Figure (A) which is the initial state.

The partition wall (S3. S.) related to piezoelectric element A deforms in the direction of decreasing volume as in the case of single salmon movement, but the partition wall (S7, S8) related to piezoelectric element B is a piezoelectric element? It transforms so that it is attracted to. Each effective discharge amount ΔSA at this time
■, △SB■ are as follows.

ΔSA■=(S■+S3+S4)−S2ΔSB. = (
S,+S,)−(s,+sa), and the magnitude relationship in each case is as follows.

ΔSA1>ΔSA■>ΔSR■ All of these occur as variations in the size of the pixel diameter.

This phenomenon occurs because the actuator (PZT) lifts the channel plate via the filler (the same applies to the diaphragm).

FIG. 1 is a block diagram for explaining an embodiment of an inkjet printing apparatus according to the present invention, in which 21 is a filler;
22 is a piezoelectric element (PZT), 23 is a channel plate, 24 is a channel, 25 is a cavity, 26 is an insulating coating, and 27 is an actuator.

Channel 24 of channel plate 23 and actuator (PZT) 22
．． 27 are configured to fit into each other, and when the actuators 27 are driven without contacting each other, the liquid in the flow path 24 can be compressed and discharged without interfering with adjacent actuators. Since the actual displacement amount of the active actuator 27 is 1 μm or less, it is sufficient to maintain a gap of several μm between the flow path 24 and the actuator 27. With a gap of this size, the fluid resistance is greater than that of the nozzle, so the pressure loss is small, and is not a problem compared to the volume loss due to deformation as in the conventional example. The piezoelectric element 22 is coated with an insulating coating 26 using sputtering or a spinner in advance to prevent short circuits.
In order to reduce the amount of liquid remaining in the slit, it is desirable to provide a gap 25 that does not touch the slit and insert the filler 21 therein.

As is clear from the above description, the present invention has the following effects.

By configuring the piezoelectric body and its corresponding flow path in a non-contact state, (1) Even if adjacent actuators are driven at the same time, each actuator will not affect each other, resulting in a uniform discharge amount and improved image quality. Not inferior.

(2) Since adjacent parts are driven at the same time, there is no need to thin out the housing, and the effective frequency does not decrease.

[Brief explanation of drawings]

FIG. 1 is a block diagram for explaining one embodiment of an inkjet recording apparatus according to the present invention, FIG. 2 is a diagram schematically showing a head section of an inkjet recording apparatus according to the present invention, and FIG. Enlarged view of part ■ in the figure, Figures 4 (.) to (c)
Figures 1 and 2 are diagrams showing the deformation of the flow path during driving using a filler as an example. Figure (a) is the initial state, Figure (b) is A drive, Figure (c
) are diagrams showing A, B, and Clli movements, respectively. 21. Filler, 22. i-electron element (PZT), 23.
...Channel plate, 24...Channel, 25...Gap, 26
...Insulating coating, 27. Actuator.

Claims (1)

[Claims] 1. A piezoelectric body is provided with slits, 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 surface of the flow path. An inkjet recording device that ejects liquid droplets from a nozzle, wherein the convex portion of the actuator and the concave portion of the parallel flow path fit into each other without contacting each other.