JPH11129465A - Ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure reliability of an adhesive sealability by increasing a thickness of a directly near part of a periphery of an ink channel thicker than an outer periphery of its outside at a displacement transfer part fixed with a piezoelectric element member and a part to be adhered with a liquid chamber for adhesively fixing the member. SOLUTION: A nozzle hole for discharging an ink droplet toward a recording medium is provided at a nozzle plate. A piezoelectric element member is constituted by a piezoelectric element for discharging an ink, a piezoelectric element base plate for holding the element, and an FPC for supplying an electric energy. A liquid chamber member is formed of an ink supply port, a common liquid chamber, a pressure chamber, a diaphragm adhering surface and a nozzle plate adhering surface. To form the channel, a part 55 to be adhered with a liquid chamber for adhesively fixing to the member, and a flexible part 53 for facilitating a displacement of a transfer part 57 disposed at an intermediate part between the part 57 and the part 55 are provided. At the part 55, a first thickness of a directly near part 59 of a periphery of the channel is formed thicker than a second thickness of the outer periphery 61 of an outside of the part 59.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a print head for a sequential printing type ink jet printer, and more particularly to an improvement of a diaphragm.

[0002]

2. Description of the Related Art As an example of a conventional diaphragm, there is International Publication No. WO93 / 25390. FIG. 4 is a perspective view showing the configuration of a conventional inkjet head. FIG. 5 is a perspective view of a main part of a conventional ink jet head viewed from below. FIG. 6 is a manufacturing process diagram of a conventional diaphragm. FIG.
In the above, 120 is a diaphragm. In FIG. 5, 120
a is a flexible portion, 120b is a displacement transmission portion, and 12
Reference numeral 4 denotes a liquid chamber bonded portion. As shown in FIG. 6, in this conventional example, a thin film 120a of 1 to 25 μm polyimide resin is formed on a metal or ceramic substrate 150 having a thickness of 0.01 to 1 mm by a casting method or the like (FIG. 6B). A photoresist 151 is formed (FIG. 6C), and a photomask 15 is formed.
The photoresist 151 is selectively exposed by irradiating ultraviolet rays 153 with the use of FIG. 2 (FIG. 6de). Next, the substrate 150 is chemically etched to form the displacement transmitting section 120b.

[0003]

The adhesive applied for adhering the liquid chamber member and the diaphragm has delicate irregularities in its thickness. If the adhesive is hardened while the fine irregularities remain, poor sealing of the ink flow path occurs. In order to cope with this, it is necessary to press the diaphragm against the liquid chamber member to fill in the unevenness of the adhesive. In a conventional example, an island-shaped protrusion or the like is formed by etching a metal or ceramic substrate having a thickness of 0.01 to 1 mm. For this reason,
The thickness of the liquid chamber adhered portion 124 is uniform in any portion, and it is not possible to positively press the portion immediately around the ink flow path. In the conventional example, since the adhesive is cured in a state where the pressing thickness is insufficient and the unevenness of the adhesive is likely to remain, there is a high probability that an adhesive seal failure occurs. In the state of poor sealing, air is mixed in when ink is sucked into the ink jet head, so that there is a disadvantage that stable ink discharge cannot be performed.

Accordingly, an object of the present invention is to secure a highly reliable adhesive seal in bonding a liquid chamber member and a diaphragm in order to reliably inject ink into an ink jet head.

[0005]

SUMMARY OF THE INVENTION A nozzle plate having a plurality of nozzle holes for discharging ink, a piezoelectric element member for generating displacement for discharging ink, and a liquid forming a part of an ink flow path An ink jet head comprising: a chamber member; and a vibration plate that forms an ink flow path in cooperation with the liquid chamber member and transmits displacement of the piezoelectric element member to the liquid chamber. A displacement transmitting portion that is fixed to the piezoelectric element member for transmission to the liquid chamber member; a liquid chamber adhered portion that is adhered and fixed to the liquid chamber member to form an ink flow path; and a position intermediate the displacement transmitting portion and the liquid chamber adhered portion. And a flexible portion for facilitating the displacement of the displacement transmitting portion.
Two thicknesses are provided, a portion near the periphery of the ink flow path is defined as a first thickness, an outer peripheral portion outside the vicinity immediately around the ink flow path is defined as a second thickness, and a first thickness near the periphery is defined as a second thickness. Is thicker than the second thickness of the outer peripheral portion.

The thickness of the adhesive applied for bonding the diaphragm to the liquid chamber member has slight irregularities, but the portion immediately adjacent to the ink flow path of the portion to be bonded to the liquid chamber is thicker than the outer peripheral portion. With this configuration, the area immediately around the periphery can be positively pressed, so that the unevenness of the adhesive can be compensated for, and the adhesive is cured in this state, so that the adhesive sealing property is ensured.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1, FIG. 2 and FIG. 3 are views showing one embodiment of the present invention. FIG. 1 is an external view of the inkjet head. The main configuration of this embodiment will be described with reference to FIG.

Reference numeral 11 denotes a nozzle plate, which has a plurality of nozzle holes for discharging ink droplets toward a recording medium.

Reference numeral 21 denotes a piezoelectric element member, which converts an electric energy into a mechanical energy to eject ink toward a recording medium;
And a FPC 27 that supplies electric energy to the piezoelectric element 23.

Reference numeral 31 denotes a liquid chamber member, and the ink supply port 3
3, common liquid chamber 35, pressure chamber 37, diaphragm bonding surface 3
9. It has a nozzle plate bonding surface 41.

Reference numeral 51 denotes a diaphragm. This will be described in detail with reference to FIG. FIG. 3A is a plan view of the diaphragm, and FIG.
(B) is a sectional view of the diaphragm viewed from below, FIG.
(D) is an enlarged view of (a) part and (b) part of FIG. 3 (b), respectively. FIG. 3E is a cross-sectional view of the diaphragm viewed from the side, and FIG. 3F is an enlarged view of a portion (C) of FIG. 3E. The vibration plate 51 has a displacement transmitting portion 57 that is fixed to the piezoelectric element member 21 of the piezoelectric element member 21 to transmit the displacement of the piezoelectric element 23 to the liquid chamber, and is adhesively fixed to the liquid chamber member 31 to form an ink flow path. And a flexible portion 53 located at an intermediate portion between the displacement transmitting portion 57 and the liquid chamber adhered portion 55 for facilitating the displacement of the displacement transmitting portion 57. The liquid chamber adhered portion 55 is provided with two types of thicknesses, the first portion near the periphery of the ink flow path 59 has a first thickness, and the outer peripheral portion 61 outside the vicinity immediately around the ink flow path 59 has a second thickness. The first thickness of the peripheral immediate vicinity portion 59 is set to be larger than the second thickness of the outer peripheral portion 61.

In order to make the thickness of the portion immediately adjacent to the periphery 59 thicker than the thickness of the outer peripheral portion 61, the width of the portion immediately adjacent to the periphery 59 is set smaller than the width of the outer peripheral portion 61, and the liquid chamber adhered portion 55 Is formed by electroforming. In the electroforming method, the current density is higher in the narrow part than in the wide part, so that the growth rate of the thickness in the narrow part becomes large, and the narrow part is formed thick in the same electroforming time, The difference A (see FIG. 3) is obtained.

Reference numeral 71 denotes a piezoelectric element holding member, and a piezoelectric element member fixing portion 73 for positioning and fixing the piezoelectric element member 51.
And a vibration plate bonding surface 75 for bonding and holding the vibration plate 51 from both sides in cooperation with the liquid chamber member 31, and a nozzle plate bonding surface 77 for bonding the nozzle plate 11.

Next, an assembling procedure will be described. First, an adhesive is applied to the entire surface of the liquid chamber member 31 bonding surface 39 of the liquid chamber member 31. The letterpress printing method is used as a coating method. As the adhesive, an epoxy one-component heat-curable adhesive is used. The vibration plate 51 is pressed against the liquid chamber member vibration plate bonding surface 39 after the adhesive application while being positioned. Heat under pressure to cure the adhesive.

In the step of bonding the liquid chamber member 31 and the diaphragm 51, a small amount of the adhesive is applied as uniformly as possible, but fine irregularities remain after the application. In the embodiment, the thickness of the adhesive applied is 3 to 5 μm, and the unevenness of the adhesive is 2 to 3 μm.
m occurs. The liquid chamber bonded portion 55 of the vibration plate 51 is bonded to the liquid chamber member 31, and a portion immediately adjacent to the periphery for bonding and sealing to secure an ink flow path has a narrow width and a large thickness.
The outer peripheral portion 61 for adhering to the first portion 1 and securing the adhesive strength is wide and slightly thinner than the immediate surrounding portion 59, and has a dimensional difference A.

In the present embodiment, two adjacent portions 59 are provided in parallel in the form of a thin line having a width of 40 μm along the pressure chamber 37 of the liquid chamber member 31 and the portion of the outer periphery of the common liquid chamber 35. The thickness is 30 μm, and the width of the outer peripheral portion 61 is 500 μm
As described above, the thickness is 26 μm, and the difference between the peripheral portion 59 and the outer peripheral portion 61 is 4 μm. Two neighboring parts 59
The flexible member 53 is formed of the same thickness and the same material as the flexible part 53 and between the peripheral part 61 and the outer peripheral part 61.

Since the peripheral portion 59 has a difference of 4 μm in thickness, the adhesive can be positively pressed by the pressure of the liquid chamber member 31 and the vibration plate 51, and can compensate for the fine irregularities at the time of applying the adhesive. Since the adhesive is cured in this pressed state, the adhesive sealing property is ensured. By the way, the thickness of the displacement transmitting section 53 is 29μ.
m, and is formed slightly thinner than the surrounding immediate vicinity 59.

Next, an adhesive is applied to the vibration element bonding surface 75 of the piezoelectric element member fixing portion of the piezoelectric element holding member 71 and cooperates with the liquid chamber member 31 so that the vibration plate 51 is bonded and sandwiched from both sides. Press and heat cure. Also in this case, the liquid chamber member 31
The piezoelectric element holding member 71 is pressed while being aligned.

Next, the liquid chamber member nozzle plate bonding surface 41, the piezoelectric element member fixing portion nozzle plate bonding surface 77, and the end surface of the vibration plate 51 are simultaneously lapped, and the liquid chamber member nozzle plate bonding surface 41 and the piezoelectric member are bonded together. The element member fixing portion nozzle plate bonding surface 77 and the end surface of the diaphragm 51 are finished to the same surface.

Next, after cleaning the same surface, an adhesive is applied, the nozzle plate 11 is set at a predetermined position, and bonded and fixed.

Next, the piezoelectric element 23 of the piezoelectric element member 21
After the adhesive is selectively applied to the upper surface, the adhesive is inserted into the piezoelectric element member fixing portion 73 of the piezoelectric element holding member 71, pressed against the vibration plate 51, heat-cured, and bonded and fixed to the vibration plate 51. The adhesive also flows into the gap between the piezoelectric element substrate 25 and the piezoelectric element member fixing portion 73 to reinforce bonding. Thus, the ink jet head is assembled.

[0022]

As described above, according to the present invention, the peripheral portion of the diaphragm to be bonded to the liquid chamber is thicker than the outer peripheral portion. It can compensate for subtle irregularities during application of the agent. For this reason,
A highly reliable adhesive seal can be ensured, ink can be reliably injected without air being mixed in when ink is taken in, and an ink jet head with stable ink discharge can be provided.

[Brief description of the drawings]

FIG. 1 is an external view of an inkjet head according to the present invention.

FIG. 2 is a diagram illustrating a main configuration of the present invention.

FIG. 3 is a diagram showing a diaphragm according to the present invention.

FIG. 4 is a perspective view showing a configuration of a conventional inkjet head.

FIG. 5 is a perspective view of a main part of a conventional inkjet head viewed from below.

FIG. 6 is a manufacturing process diagram of a conventional diaphragm.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Nozzle plate 21 Piezoelectric element member 23 Piezoelectric element 31 Liquid chamber member 51 Vibration plate 57 Displacement transmitting part 59 Peripheral part 61 Outer peripheral part 71 Piezoelectric element holding member

Claims (1)

[Claims] 1. A nozzle plate having a plurality of nozzle holes for discharging ink, a piezoelectric element member for generating displacement for discharging ink, a liquid chamber member forming a part of an ink flow path, A vibration plate that forms an ink flow path in cooperation with the liquid chamber member and transmits the displacement of the piezoelectric element member to the liquid chamber, wherein the vibration plate transmits the displacement of the piezoelectric element to the liquid chamber. A displacement transmitting portion fixed to the piezoelectric element member, a liquid chamber bonded portion bonded and fixed to the liquid chamber member to form an ink flow path, and a displacement transmitting portion located between the displacement transmitting portion and the liquid chamber bonded portion. And a flexible part for facilitating displacement of the ink chamber. The liquid chamber adhered part is provided with two kinds of thicknesses, and a part near the periphery of the ink flow path is set to the first thickness, and the periphery of the ink flow path is The outer peripheral portion on the outer side of the immediate vicinity is set to the second thickness, and Thickness inkjet head is characterized by being configured thicker than the second thickness of the outer peripheral portion.