JPH08258258A - Inkjet head - Google Patents

Abstract

PURPOSE: To enable the good emission of ink without allowing an adhesive to protrude even when the coating amt. of the adhesive is much by providing a stepped part to the bonded part with a common ink chamber forming member of an ink supply member in an ink jet head. CONSTITUTION: In order to obtain an ink jet head, a common ink chamber forming member 12B, a nozzle forming member 11, a common ink chamber forming member 12A, a pressure chamber forming member 3, a vibration member 14 and piezoelectric elements 15 are laminated. The members 11, 12A are formed using SUS 316L and nozzles 17, a common ink chamber 18 and communication holes 21A are formed by pressing or electroforming. An ink supply member 16 coated with an adhesive is aligned with the member 12B to be laminated to the member 12B under pressure and heating. In this case, since a stepped part 25A is provided to the ink supply member 16, even when the coating amt. of the adhesive is much, the gap between the members on the side of the stepped part 25A is narrow and flow resistance becomes large. As a result, the excessive adhesive flows to the opposite side of the stepped part 25A and the adhesive 24 becomes hard to protrude toward ink passages.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet head used in an apparatus such as a printer which ejects ink drops to form an ink image on a medium such as recording paper.

[0002]

2. Description of the Related Art Many examples of known ink jet heads have been disclosed as known techniques for use in an apparatus such as a printer that ejects ink droplets to form an ink image on a medium such as recording paper.

FIG. 4 is a schematic cross-sectional view of a conventional ink jet head. The common ink chamber forming members 12A and 12B are joined to the nozzle forming member 11 provided with the plurality of nozzles 17, and the nozzle forming member 1
1. The common ink chamber 18 is formed by the space formed by the common ink chamber forming members 12A and 12B. Further, the pressure chamber forming member 13 is joined to the common ink chamber forming member 12B, and further the vibrating member 14 and the piezoelectric element 15 as the pressure generating means are joined to the vibrating member 14, the pressure chamber forming member 13, and the common ink. The pressure chamber 20 is formed by the space formed by the chamber forming member 12B. The pressure chamber 20 and the common ink chamber 18 communicate with each other through an ink inflow hole 19 provided in the common ink chamber forming member 12B. Further, the pressure chamber 20 and the nozzle 17 have the common ink chamber forming members 12A and 1A.
The communication holes 21A and 21B provided in 2B communicate with each other.

In FIG. 4, the nozzles 17 are arranged in a direction perpendicular to the plane of the drawing, and the communication holes 21 corresponding to the nozzles 17 are formed.
The common ink chamber forming members 12A and 12B, the pressure chamber forming member 13, and the vibrating member 14 are formed so that A, 21B, the pressure chamber 20, and the ink inflow hole 19 are arranged.

The ink supply member 16 is joined to the common ink chamber forming member 12B, and the ink supply path 23 is formed.
The common ink chamber 18 and the common ink chamber 18 communicate with each other through an ink supply hole 22 provided in the common ink chamber forming member 12B.

In the ink jet head thus constructed, the piezoelectric element 15 is deformed by charging and discharging to bend the vibrating member 14 to pressurize the ink in the pressure chamber 20 and eject the ink from the nozzle 17.

[0007]

Here, the ink supply member 16 is bonded to the common ink chamber forming member 12B after the adhesive is applied to the adherend surface. At this time, if the application amount of the adhesive is large, the adhesive protrudes into the ink supply path 23 and the ink supply hole 22 and is cured.

FIG. 5 is an enlarged view of portion A of FIG.
When the adhesive 24 sticks out to the ink supply path 23 and the ink supply hole 22 and is hardened, the air bubbles 26 are likely to stay at that portion.

The ink supply member 16 is connected to an ink container (not shown), from which ink is supplied. When the ink in the ink container is used up, it is replaced with a new ink container. At this time, air enters, which causes bubbles. Therefore, a suction pump is used to suck bubbles together with the ink from the nozzle 17. Here, when the flow rate of ink is the same, the flow velocity decreases when the ink flow path is thick, and the flow velocity increases when the ink flow path is thin. Therefore, the flow velocity of the common ink chamber 18 and the ink supply passage 23, which have a larger volume than the pressure chamber 20, becomes smaller. Therefore, bubbles in the ink do not easily flow, and if there is a protruding portion of the adhesive between the ink supply member 16 and the common ink chamber forming member 12B, the bubbles are likely to stay in that portion.

The accumulated air bubbles flow into the pressure chamber 20 due to the vibration of the movement of the ink jet head due to the printing operation. When the air bubbles enter the pressure chamber 20, the pressure at the time of pressurizing the ink is absorbed by the air bubbles, and the ink ejection amount is lowered. The print may be blurred or the print may be misaligned due to a decrease in the ink ejection speed.
The problem arises. Further, when the bubbles further flow and the bubbles come out from the nozzle 17 during printing, there is a problem that the printing at that portion is omitted.

The present invention is intended to solve these problems. An object of the present invention is to provide an ink jet head capable of excellent ink ejection without sticking out of the adhesive even when the amount of the adhesive applied is large. It is to be.

[0012]

An ink jet head according to the present invention includes a nozzle forming member having a plurality of nozzle openings, a pressure chamber forming member forming a pressure chamber corresponding to each nozzle opening, and the pressure. A vibrating member having pressure generating means corresponding to the chamber, and a common ink chamber forming member for forming a common ink chamber for supplying ink to the pressure chamber,
An ink jet head having an ink supply member that supplies ink to the common ink chamber, characterized in that a step portion is provided at a joint portion of the ink supply member and the common ink chamber forming member.

Further, the ink supply member and the common ink chamber forming member are joined by an adhesive having a viscosity of 100,000 mPa · s or more and 1,000,000 mPa · s or less.

[0014]

According to the present invention, by adopting the above-mentioned structure, when the adhesive is applied to the adhered surface of the ink supply member and the same is adhered to the common ink chamber forming member, even when the adhesive is applied in a large amount, Due to the difference in flow resistance and the formation of an escape space for the adhesive, the adhesive is less likely to flow forward than the step. As a result, the adhesive does not overflow, and a smooth ink flow path can be obtained.

[0015]

EXAMPLES The present invention will be described below with reference to specific examples, but it goes without saying that the present invention is not limited to this and can be modified within the scope of the invention.

[Embodiment 1] FIG. 1 is a schematic sectional view of an embodiment of an ink jet head according to the present invention, and FIG. 2 is a partially enlarged view of FIG.

The material of the ink supply member 16 is not particularly limited as long as it is a material that is durable against ink, but in order to easily form the step 25A, a known material for metal casting or plastic molding. And methods are used. Polysulfone was used as the ink supply member in this example.

The material of the common ink chamber forming member 12B is not particularly limited as long as it has durability against ink and has good workability. SUS316L was used as the common ink chamber forming member 12B in this embodiment. The ink supply hole 22, the ink inflow hole 19, and the communication hole 21B are pressed,
It is formed by a known method such as electroforming.

The ink supply member 16 and the common ink chamber forming member 12B are bonded together after applying a small amount of the adhesive 24. The type of adhesive is suitable for bonding metal and plastic, and is not particularly limited as long as the viscosity is 100,000 mPa · s or more and 1,000,000 mPa · s or less. In this example, a known epoxy adhesive was used. Application of the adhesive to the ink supply member 16 is performed by a known method such as a constant-volume ejector or pad transfer.

The ink supply member 16 coated with the adhesive is
The common ink chamber forming member 12B is aligned by a known method, and pressure and heat are applied to bond the members. In this case, in this embodiment, since the ink supply member 16 is provided with the step 25A, the gap between the members is narrower on the step 25A side even when the adhesive application amount is large.
Flow resistance increases. Therefore, the extra adhesive is 25
It flows to the side opposite to A, and it becomes difficult for the adhesive 24 to protrude to the ink flow path side.

In order to obtain the ink jet head as shown in FIG. 1, the common ink chamber forming member 12B, the nozzle forming member 11, the common ink chamber forming member 12A, the pressure chamber forming member 13, the vibrating member 14, and the piezoelectric element 15 are attached. To match.
The materials of the nozzle forming member 11, the common ink chamber forming member 12A, the pressure chamber forming member 13, and the vibrating member 14 are not particularly limited as long as they are durable to ink and have good workability. Nozzle forming member 1 of this embodiment
1. SUS316L was used for the common ink chamber forming member 12A. The nozzle 17, the common ink chamber 18, and the communication hole 21A are formed by a known method such as pressing or electroforming. The pressure chamber forming member 13 and the vibrating member 14 of this embodiment are made of known ceramic materials.

Nozzle forming member 11, common ink chamber forming members 12A and 12B, pressure chamber forming member 13, vibrating member 14
Is aligned by a known method, and is bonded using a known adhesive. Nozzle forming member 1
1. The common ink chamber forming members 12A and 12B, the pressure chamber forming member 13, and the vibrating member 14 may be pasted together and then the ink supply member 16 may be pasted, or the ink supply member 16 and the common ink chamber forming member 12B may be pasted. After combining, the nozzle forming member 11, the common ink chamber forming member 12A,
The pressure chamber forming member 13 and the vibration member 14 may be bonded together.

An ink jet head having a 12-nozzle array is produced by the above method.

[Embodiment 2] FIG. 3 is a partially enlarged view of a schematic sectional view of another embodiment of the ink jet head according to the present invention. The ink supply member 16 is formed in the direction in which the step 25B is raised, contrary to the first embodiment. Step 25B
The known material and method for metal casting or plastic molding can be used for forming
As in Example 1, the ink supply member 16 uses polysulfone. The ink supply member 16 formed in this manner is the same as that of the first embodiment in the nozzle forming member 11,
The common ink chamber forming members 12A and 12B, the pressure chamber forming member 13, the vibrating member 14, and the piezoelectric element 15 are bonded together and
An inkjet head having a two-nozzle array is created. In this case, in this embodiment, since the ink supply member 16 is provided with the step 25B, the gap between the members is widened by the step 25B even when the adhesive application amount is large, and the adhesive escape space is provided. Is formed. Therefore, the excess adhesive flows so as to fill the escape space. Therefore, the adhesive 24 is less likely to stick out.

[Comparative Example] FIG. 4 is a schematic sectional view of an ink jet head according to the prior art, and FIG. 5 is a partially enlarged view of FIG.

The ink supply member 16 has no step. The ink supply member 16 having no step is formed by the nozzle forming member 11 in the same manner as in the first embodiment.
The common ink chamber forming members 12A and 12B, the pressure chamber forming member 13, and the vibrating member 14 are bonded together to form an inkjet head having a 12-nozzle arrangement.

The inkjet heads produced based on Examples 1 and 2 and Comparative Example were subjected to the following preparatory operations and then each evaluation.

<Preparation Operation> After the ink jet head is connected to the ink container to fill the ink, the ink container is repeatedly attached and detached 5 times to mix air. Then, as a bubble discharging operation, ink is sucked from the nozzle using a suction pump.

<Evaluation 1> Evaluation of ink ejection. The inkjet ink disclosed by the present applicant is used to eject ink, and the ink ejection speed and the ink ejection weight per dot are measured.

<Evaluation 2> Evaluation of printing. Each inkjet head is attached to a known inkjet recording device, printing is performed on the recording paper, and the print fading, misalignment, and omission are evaluated. ⊚: No print fading, misalignment, or omission (suitable). X: Print is faint, misaligned, or missing (unsuitable).

<Evaluation 3> Adhesive surface inspection. After the ink jet head after the printing evaluation is washed to remove the ink, the ink supply member and the common ink chamber forming member are peeled off. Then, the adhesive surface is observed with a microscope having a magnification of 20 to 40, and it is checked whether or not the adhesive has overflowed into the ink flow path. ⊚: Adhesive does not protrude into the flow path (optimum). ◯: The adhesive is protruding into the flow channel, but is not wrapping around the side wall of the bonding surface (suitable). X: The adhesive is protruding into the flow path (unsuitable).

Table 1 shows the results of these evaluations.

[0033]

[Table 1]

In each of the first and second embodiments, the evaluation 1 gives a good result that the ink ejection speed is high, the amount of ejected ink is large, and the difference between the maximum value and the minimum value between the nozzles is small. The results of 2 and Evaluation 3 were all optimum or suitable. On the other hand, in the comparative example, the evaluation 1 was not suitable because the difference between the maximum value and the minimum value between the nozzles was large, and the value of the minimum value was far below the numerical value of the example. Further, in Evaluation 2, nozzles with faint print, misalignment, and omission were found scattered, which was not suitable. Further, in Evaluation 3, the adhesive was squeezed out into the ink flow path, which was not suitable.

[0035]

As described above, the ink jet head of the present invention has a structure in which a step is provided at the portion of the ink supply member that is joined to the common ink chamber forming member. Therefore, even if the amount of adhesive applied is large, the adhesive does not overflow into the ink flow path due to the difference in flow resistance and the formation of escape space for the adhesive. Therefore, it becomes difficult for bubbles to stay. Therefore, the decrease in the ink discharge speed and the decrease in the discharged ink amount due to the bubbles flowing into the pressure chamber during printing are eliminated, and stable printing can be continuously performed. Further, since the operation for discharging bubbles is minimized, the ink consumption can be reduced, the suction pump can be downsized, and the power consumption can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of an inkjet head of the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a partially enlarged view of a cross-sectional view of another embodiment of the inkjet head of the present invention.

FIG. 4 is a cross-sectional view of an inkjet head according to the related art.

FIG. 5 is a partially enlarged view of FIG.

[Explanation of symbols]

 11 Nozzle Forming Member 12 Common Ink Chamber Forming Member 13 Pressure Chamber Forming Member 14 Vibration Member 15 Piezoelectric Element 16 Ink Supply Member 17 Nozzle 18 Common Ink Chamber 19 Ink Inlet Hole 20 Pressure Chamber 21 Communication Hole 22 Ink Supply Hole 23 Ink Supply Channel 24 Adhesive 25 Step 26 Bubble

Claims (2)

[Claims] 1. A nozzle forming member having a plurality of nozzle openings, a pressure chamber forming member forming a pressure chamber corresponding to each nozzle opening, and a pressure generating means corresponding to the pressure chamber are provided. An ink jet head comprising a vibrating member, a common ink chamber forming member for forming a common ink chamber for supplying ink to the pressure chamber, and an ink supply member for supplying ink to the common ink chamber, An ink jet head having a step portion at a joint portion of an ink supply member and the common ink chamber forming member. 2. The ink supply member and the common ink chamber forming member have a viscosity of 100,000 mPa · s or more 1,0.
The ink jet head according to claim 1, wherein the ink jet head is joined by an adhesive having a viscosity of not more than 0,000 mPa · s.