JPH1134324A - Ink jet recorder and ink jet head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance reliability of a diaphragm of an ink jet head for discharging an ink droplet from a nozzle by electrically grounding the diaphragm, thereby preventing flow-out of metal ion in the diaphragm into the ink to open a hole. SOLUTION: When a nozzle cover 3 is mounted at an end of a diaphragm 42 of the ink jet head, a protruding part 42a brought into pressure contact with an inner surface of the cover 3 by elasticity is integrally formed. And, the cover 3 is electrically connected to a ground (GND) of an ink jet recorder body (printer body). That is, the diaphragm 42 is electrically connected to the cover 3 via the part 42a, and electrically connected to the GND of the body via the cover 3. Thus, an induced voltage of the diaphragm 42 is fed to the ground thereby to prevent elution of metal ion of the diaphragm 42 into the ink, and hence dissolution of the diaphragm 42 to hole a hole is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus and an ink jet head, and more particularly to an ink jet head using a diaphragm and an ink jet recording apparatus provided with the head.

[0002]

2. Description of the Related Art In general, an ink jet head constituting a recording head of an ink jet recording apparatus used for a printer, a facsimile, a copying machine, etc. has a plurality of nozzle holes for discharging ink droplets, and an ink liquid chamber corresponding to each nozzle hole. (Also referred to as a “pressurized liquid chamber”), and energy generating means such as an electromechanical conversion element such as a piezoelectric element or an electrothermal conversion element such as a heater for pressurizing the ink in the ink liquid chamber. By driving in accordance with the recording signal, the ink in the required ink liquid chamber is pressurized to eject ink droplets from the nozzle holes.

[0003] As such an ink jet head,
Conventionally, as described in, for example, JP-A-9-76534, a laminated piezoelectric element is arranged on an insulating substrate,
A diaphragm having a diaphragm is laminated on the piezoelectric element, and an ink liquid chamber pressurized by the piezoelectric element via the diaphragm and an ink supply path for supplying ink to the ink liquid chamber are formed on the diaphragm. It is known that a liquid chamber partition member to be formed is laminated, and a nozzle forming member having a nozzle formed thereon is further laminated on the liquid chamber partition member.

[0004]

Incidentally, the laminated piezoelectric element is laminated as an electrode layer on the lamination interface of the piezoelectric body through an alloy such as silver-palladium, and these metals have a role of bonding the piezoelectric body between the layers. have. The same can be said for the uppermost layer of a laminated piezoelectric element in which a vibration plate made of a metal plate is joined, and the vibration plate becomes one electrode layer and electric ions are accumulated by capacitive coupling.

In this case, if the vibration plate is joined to a place having an electrically low potential difference via the ink, a current flows. Specifically, the diaphragm and the nozzle forming member are in an insulated state, and the nozzle forming member is grounded (dropped to ground) through a nozzle cover or the like. At this time, with the voltage induced on the diaphragm by the capacitive coupling, a current flows from the diaphragm to the ground via the nozzle plate via the nozzle plate via the ink.
As a result, metal ions of the diaphragm, for example, Ni ions flow out when the diaphragm is formed of nickel.

However, since a diaphragm having a thin layer of about several μm is formed on the diaphragm in order to efficiently transmit the displacement of the piezoelectric element to the ink liquid chamber, when ion outflow occurs, the diaphragm is placed on the diaphragm. A hole will be easily drilled. When the vibration plate has such a hole, the ink in the ink liquid chamber penetrates the periphery of the piezoelectric element to reduce the piezoelectric function, and as a result, ejection failure occurs.

The present invention has been made in view of the above points, and an object of the present invention is to provide an ink jet recording apparatus and an ink jet head capable of preventing long-term stable printing by preventing a metal diaphragm from melting. And

[0008]

According to a first aspect of the present invention, there is provided an ink jet recording apparatus which pressurizes ink in an ink liquid chamber via a vibration plate by a displacement of an electromechanical transducer and causes the ink to flow from a nozzle. In an ink jet recording apparatus provided with an ink jet head for discharging droplets, a configuration was adopted in which the diaphragm of the ink jet head was electrically grounded.

According to a second aspect of the present invention, in the inkjet recording apparatus of the first aspect, the inkjet head includes an electrically grounded nozzle cover, and the diaphragm is electrically connected to the nozzle cover. Configuration.

According to a third aspect of the present invention, there is provided the ink jet recording apparatus according to the first aspect, wherein an electrically grounded conductive pattern is formed on the insulating substrate on which the electromechanical transducer is provided. And the diaphragm is electrically connected to the diaphragm.

According to a fourth aspect of the present invention, there is provided an ink jet head for discharging ink droplets from nozzles by pressurizing ink in an ink liquid chamber via a vibration plate by displacement of an electromechanical transducer. The member and the diaphragm are electrically connected to each other.

According to a fifth aspect of the present invention, there is provided the ink jet head according to the fourth aspect, further comprising an electrically grounded nozzle cover, wherein the nozzle cover is electrically connected to the nozzle forming member. did.

According to a sixth aspect of the present invention, in the inkjet head of the fourth aspect, a conductive pattern that is electrically grounded is formed on an insulating substrate on which the electromechanical transducer is provided. The diaphragm was electrically connected.

According to a seventh aspect of the present invention, in the ink jet head of the fourth aspect, the nozzle forming member and the vibration plate are in a state of being electrically floating while being in a conductive state.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an exploded perspective view showing an example of an ink jet head to which the present invention is applied, FIG. 2 is an enlarged cross-sectional view of a main part in a direction orthogonal to a channel direction (nozzle arrangement direction) of the head, and FIG. 3 is an enlarged sectional view of a main part of FIG.

This ink jet head includes a drive unit 1, a liquid chamber unit 2, and a head cover 3. The drive unit 1 is configured such that a plurality of laminated piezoelectric elements 12 as energy generating means are arranged in two rows and joined on a ceramic substrate, for example, an insulating substrate 11 such as barium titanate, alumina, or forsterite. A frame member 13 made of resin, ceramic, or the like surrounding the periphery of each of the two rows of piezoelectric elements 12 is joined by an adhesive 14.

The plurality of piezoelectric elements 12 are provided between piezoelectric elements 17 (to be referred to as “driving units”) to which a driving pulse for applying ink to droplets and flying is provided, and driving units 17. A piezoelectric element (hereinafter, referred to as a “non-driving unit”) serving as a liquid chamber support member that is located and receives a driving pulse and simply fixes the liquid chamber unit 2 to the substrate 11.
... are alternately configured.

Here, as the piezoelectric element 12, a laminated piezoelectric element having ten or more layers is used. This laminated piezoelectric element has a thickness of 10 to 50 μm / 1, for example, as shown in FIG.
Layer of lead zirconate titanate (PZT) 20 and a thickness of several μ
An internal electrode 21 made of silver / paradium (AgPd) of m / 1 layer is alternately laminated, but the material used for the piezoelectric element is not limited to the above, and other electromechanical conversion elements may be used. Can also.

The internal electrodes 21 of each piezoelectric element 12 are left and right end electrodes 22 and 23 made of AgPd every other layer (the opposing surfaces of the two rows of piezoelectric elements are end electrodes 22 and the non-opposing surfaces are end electrodes. 23). On the other hand, as shown in FIG.
Each pattern of the common electrode 24 and the individual electrode 25 is provided by Au plating, AgPt paste printing, AgPd paste printing, or the like.

Then, the opposite end electrodes 22 of each row of the piezoelectric elements 12 are connected to the common electrode 24 via a conductive adhesive 26.
On the other hand, the non-opposing end surface electrodes 23 of the piezoelectric elements 12 in each row are connected to the individual electrodes 25 via the conductive adhesive 26 in the same manner. Thereby, the driving unit 17
When a drive voltage is applied to the drive unit 17, an electric field is generated in the stacking direction, and the driving unit 17 is displaced in the stacking direction (d 33).
Direction displacement) occurs. As shown in FIG. 2, the common electrode 24 has a hole 13a formed in the frame member 13.
By filling the inside with the conductive adhesive 26, the pattern connected to each piezoelectric element is conducted.

On the other hand, the liquid chamber unit 2 includes a diaphragm 31 made of a metal material, a liquid chamber partition member 32 having a two-layer structure formed of a photosensitive resin layer made of a dry film resist (DFR), and a metal material. The nozzle plate 33 and the nozzle plate 33 are sequentially laminated and formed by heat fusion. By each of these members, one piezoelectric element 12 (driving unit 17)
Diaphragm portions 34 corresponding to the two piezoelectric elements 12 and a pressurized liquid chamber 35 pressurized through each diaphragm portion 34
The common liquid chambers 36, 36 located on both sides of the pressurized liquid chamber 35 for introducing ink to be supplied to the pressurized liquid chamber 35, and the pressurized liquid chamber 35 and the common liquid chambers 36, 36 communicate with each other. One channel is formed by the ink supply paths 37, 37 and the nozzle 38 communicating with the pressurized liquid chamber 35, and a plurality of channels are provided in two rows.

The diaphragm 31 is formed of a metal material, for example, a Ni plating film by an electroforming method. The diaphragm 34 corresponding to the drive unit 17, the beam 41 and the frame member joined to the non-drive unit 18 are provided. Base 4 bonded to 13
2 are formed. The diaphragm section 34 includes the driving section 1
7 and an outermost thin film portion (diaphragm region) 44 having a thickness of about 3 to 10 μm formed around the convex portion 43.

The liquid chamber partition member 32 is formed by laminating a dry film resist in advance on the diaphragm 31 side, exposing it using a required mask, and developing it to form a first photosensitive resin layer 45 having a predetermined liquid chamber pattern. And a second photosensitive resin layer 46 having a predetermined liquid chamber pattern formed by laminating a dry film resist in advance on the nozzle plate 33 side, exposing using a required mask, and developing the predetermined liquid chamber pattern. Become.

The nozzle plate 33 is formed of a metal material, for example, a Ni plating film by an electroforming method, and has a large number of nozzles 38 which are fine discharge ports for ejecting ink droplets. The inner shape (inner shape) of the nozzle 38 is formed in a horn shape (may be a substantially columnar shape or a substantially truncated cone shape). The diameter of the nozzle 38 is about 25 to 35 μm on the ink droplet outlet side.

The ink ejection surface (nozzle surface side) of the nozzle plate 33 is a water-repellent surface 47 which has been subjected to a water-repellent surface treatment as shown in FIG. For example, PTF
Ink physical properties such as E-Ni eutectoid plating, electrodeposition coating of fluororesin, vapor-deposited evaporative fluororesin (for example, pitch fluoride), baking after solvent application of silicon resin or fluorine resin The water-repellent treatment film selected according to the above is provided to stabilize the ink droplet shape and the flying characteristics so that high-quality image quality can be obtained. The periphery of the nozzle plate 33 is a non-water-repellent surface 48 on which no water-repellent film is formed.

The substrate 11 of the drive unit 1 and the piezoelectric element 12 and the frame member 13 are assembled by bonding with an adhesive 49, and the liquid chamber unit 2 is processed and assembled separately from the drive unit 1. After that, the vibration plate 31 of the liquid chamber unit 2 and the piezoelectric element 12 and the frame member 13 of the drive unit 1 are joined with an adhesive 50 to form an ink jet head.

The substrate 11 is supported and held on a spacer member (head holder) 51 serving as a head support member.
C and the electrodes 24 and 25 connected to the piezoelectric elements 12 (drive unit 17) of the drive unit 1
They are connected via PC cables 53,53.

A nozzle cover (head cover) 3
Is made of a metal material formed in a box shape to cover the periphery of the nozzle plate 33 and the side surface of the head.
An opening is formed corresponding to the water-repellent surface 47 of the nozzle plate 33, and is bonded to the non-water-repellent surface 48 remaining on the peripheral portion of the nozzle plate 33 with an adhesive. Further, in order to supply ink from an ink cartridge (not shown) to the liquid chamber, a spacer member 51, a substrate 11,
The frame member 13 and the diaphragm 31 are provided with ink supply holes 54 to 57, respectively.

In the ink jet head configured as described above, by applying a drive waveform (pulse voltage of 10 to 50 V) to the drive unit 17 in accordance with the recording signal, a displacement in the stacking direction occurs in the drive unit 17, and Diaphragm 31
The pressurized liquid chamber 35 is pressurized through the diaphragm section 34 of the above, and the pressure rises, and ink droplets are ejected from the nozzle 38. At this time, ink flows also in the direction of the ink supply passages 37, 37 leading from the pressurized liquid chamber 35 to the common liquid chamber 36. However, by reducing the cross-sectional area of the ink supply passages 37, 37, the fluid resistance portion is reduced. Function to reduce the flow of ink toward the common liquid chambers 36, 36, thereby preventing a drop in ink ejection efficiency.

Then, with the end of the ink droplet ejection, the ink pressure in the pressurized liquid chamber 35 decreases, and a negative pressure is generated in the pressurized liquid chamber 34 due to the inertia of the ink flow and the discharge process of the drive pulse. To the ink filling process. At this time, the ink supplied from the ink tank flows into the common liquid chambers 36, 36, and from the common liquid chambers 36, 36 to the ink supply paths 37, 3.
After that, it is filled into the pressurized liquid chamber 35. Then, the vibration of the ink meniscus surface near the outlet of the nozzle 38 is attenuated,
When the ink is returned to the vicinity of the outlet of the nozzle 38 due to surface tension (refill) and reaches a stable state, the operation shifts to the next ink droplet ejection operation.

Next, a first embodiment in which the present invention is applied to this ink jet head will be described with reference to FIGS. In the first embodiment, as shown in FIG. 4, the nozzle cover 3 is attached to the end of the diaphragm 42 of the ink jet head.
Is integrally formed with a protruding portion 42a which is pressed by elasticity on the inner surface when is mounted. The nozzle cover 3 is electrically connected to a ground (hereinafter, also referred to as "GND") of an ink jet recording apparatus main body (hereinafter, referred to as "printer main body").

That is, as shown in FIG. 5, nozzle positions of a plurality of colors, for example, heads H... Of yellow (Y), magenta (M), cyan (C), black (Bk), etc. are aligned for each color. Each head H
G provided with the nozzle cover 3 of...
By connecting to the ND line 62 with the connection terminal 63, the nozzle cover 3 of each head H is collectively connected to the GN of the printer main body.
Connect to D.

With such a configuration, the diaphragm 42 is electrically connected to the nozzle cover 3 via the protruding portion 42a.
ND is electrically connected to ground.

The operation of this embodiment will be described with reference to FIG. 6 as well. As described above, the driving waveform of the piezoelectric element 12 has a sharp rise and a gentle fall as shown in FIG. (Drive voltage)
Since the diaphragm 42 joined to the uppermost layer of the piezoelectric element 12 is formed of a metal material, the diaphragm 42 becomes a kind of electrode material, and a voltage is induced by capacitive coupling with the piezoelectric element 12. The induced voltage induced in the diaphragm 42 also has a steep rise and a gentle fall waveform as shown in FIG. However, when the driving voltage is about 25 V, the induced voltage is about 15 V, which is about 60%.

Here, even if the diaphragm 42 is not electrically grounded as described above, no charge flows if the diaphragm 42 is electrically floating, but the diaphragm 42 is provided to face the diaphragm 42. Due to the nozzle plate 33 made of a metal material, metal ions in the vibration plate 42 are eluted through the conductive ink, whereby a hole is made in the thinnest diaphragm portion 44 of the vibration plate 42 and the ink is moved to the piezoelectric element 12 side. May spill.

On the other hand, as in this embodiment, a projection 42a is provided on the diaphragm 42, and the projection 42a is pressed against the electrically grounded nozzle cover 3, and By electrically grounding, the induced voltage of the vibrating plate 42 flows to the ground, so that the induced voltage prevents the metal ions of the vibrating plate 42 from being eluted into the ink, and the vibrating plate 42 is dissolved. Drilling is prevented.

Since the diaphragm is electrically grounded in this way, the diaphragm is prevented from being melted by the induced voltage, so that the reliability of the diaphragm is improved and stable long-term ink droplet ejection can be performed. As a result, the printing quality can be ensured. In this case, by grounding the diaphragm via the nozzle cover as in this embodiment, when a plurality of heads are provided as in a color ink jet recording apparatus, the diaphragms of the plurality of heads are collectively the same. The potential can be lowered to improve the productivity.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, a groove 66 for applying a conductive adhesive is formed on the outer wall of the frame member 13 corresponding to the GND line 65 which is a grounded conductive pattern formed on the substrate 11, and the groove 66 is formed. A conductive adhesive 68 that electrically connects the vibration plate 42 bonded on the frame member 13 and the GND line 65 on the substrate 11 is applied inside 66. The GND line 65 of the board 11 is connected to the PCB board 52 through the GND line 53a of the FPC cable 53, and is connected to the G
Grounded to ND.

As a result, the vibration plate 42 is connected to the GND line 65 on the substrate 11 via the conductive adhesive 68, and the G line of the FPC cable 53 is further connected from the GND line 65.
Since the printer body is grounded via the ND line 53a and the PCB board 52, the induced voltage of the diaphragm 42 can be reduced to ground as in the first embodiment. Is prevented from being eluted into the ink.

As described above, the diaphragm can be electrically grounded within the head alone by electrically connecting the grounded conductive pattern formed on the substrate to the diaphragm. Even when a plurality of heads are used as described above, it is possible to ensure the reliability of the dissolution preventing process for each head before mounting the head in the inkjet recording apparatus.

Next, a third embodiment of the present invention will be described with reference to FIG. Also in this embodiment, a through hole 67 for filling the frame member 13 with a conductive adhesive is formed corresponding to the GND line 65 which is a conductive pattern formed on the substrate 11, and a vibration is formed in the hole 67. Plate 42 and substrate 1
A conductive adhesive 68 for electrically connecting to the GND line 65 on the upper surface 1 is applied.

Therefore, as in the second embodiment, the diaphragm 42 is connected to the GN on the substrate 11 via the conductive adhesive 68.
D line 65 and GND line 65 to F
GND line 53a of PC cable 53, PCB board 5
2 is grounded to the printer body via
2, the induced voltage can be dropped to the ground, and the induced voltage prevents metal ions of the diaphragm 42 from being eluted into the ink.

As described above, by electrically connecting the diaphragm to the conductive pattern formed on the substrate and the diaphragm, the diaphragm can be electrically grounded within the head alone. Even when a plurality of heads are used as described above, it is possible to ensure the reliability of the dissolution preventing process for each head before mounting the head in the inkjet recording apparatus. Then, when forming a through hole for filling the conductive adhesive as in this embodiment,
By applying a conductive adhesive in the through hole before the diaphragm is joined, the diaphragm can be joined to the frame member and the piezoelectric element with an epoxy adhesive, etc., and at the same time, electrical connection can be made. Can be shortened.

Next, a fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, the nozzle plate 3
3 and the liquid chamber partition member 32 are formed with through holes 71 and 72, and the through holes 71 and 72 are filled with a conductive adhesive 73 to electrically connect the vibration plate 42 and the nozzle plate 33. ing. For example, a hole (about 0.8φ) is formed in the nozzle plate 33 so that a needle of the dispenser can be inserted, and a similar hole is formed in the liquid chamber partition member 32.

Accordingly, in order to prevent a potential difference between the vibration plate 42 and the nozzle plate 33, even when a potential difference occurs between the nozzle plate 33 and the vibration plate 42, the metal ions on the vibration plate 42 Elution into the inside is prevented, the reliability of the diaphragm is improved, ink droplets can be stably ejected over a long period of time, and printing quality can be ensured.

By simply bringing the diaphragm 42 and the nozzle plate 33 into a conductive state and electrically floating, the electric charge induced in the diaphragm 42 does not flow out, so that it is inexpensive and easy. Vibrating plate 42 by induced voltage
Can be prevented from dissolving. In order to electrically connect the vibration plate 42 and the nozzle plate 33 so that the nozzle plate 33 is electrically floated, the head mounting base may be formed of an insulating material and the nozzle cover 3 may be grounded.

Next, a fifth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In this embodiment, the nozzle cover 3 is pressed against the nozzle plate 33 of the fourth embodiment to be electrically connected. And the nozzle cover 3 is the first
As in the embodiment (see FIG. 5), the GND of the printer body
Connected to

Therefore, diaphragm 42 is made of conductive adhesive 7
The diaphragm 4 is grounded via the nozzle cover 3 and the nozzle cover 3 and the like.
Since the voltage induced in 2 will flow to the ground,
The metal ions of the vibration plate 42 are prevented from being eluted into the ink by the induced voltage, the reliability of the vibration plate is improved, the ink droplets can be stably ejected for a long time, and the printing quality is secured. Can be. In this case, the liquid chamber components that come into contact with the inks of the plurality of heads can be made to have the same potential difference, and are in an electrically stable state, so that elution from not only the diaphragm but also the nozzle plate can be prevented. The performance is improved.

Next, a sixth embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In this embodiment, the frame member 1
3, a through hole 75 is formed at a position corresponding to the GND pattern 65 on the substrate 11 similarly to the third embodiment, and a through hole is formed at a position corresponding to the through hole 75 in the vibration plate 42 and the liquid chamber partition member 32. Holes 76 and 77 are formed, a conductive adhesive 78 is filled in these through holes 75 to 77, and the nozzle plate 33 and the vibration plate 42 are connected to the GND on the substrate 11 via the conductive adhesive 78. It is connected to the pattern 65, and is connected to GND of the printer main body via the GND pattern 65, the FPC cable 53, and the PCB board 52.

As a result, the diaphragm 42 is electrically connected to the nozzle plate 33 and grounded via the conductive adhesive 78, the GND pattern 65, etc., so that the voltage induced on the diaphragm 42 flows to the ground, and the induced voltage Diaphragm 4
2 is prevented from flowing out into the ink,
The reliability of the diaphragm is improved, and stable printing quality can be secured. In addition, since the nozzle plate 33 is also grounded, elution of metal ions from the nozzle plate 33 is prevented.

In this manner, the diaphragm and the nozzle plate are brought into conduction, and each head is dropped to GND in its own PCB substrate, so that the diaphragm can be reliably dropped to the ground in a single head state. Thus, elution of metal ions from the diaphragm and the nozzle plate can be prevented.

[0052]

As described above, according to the ink jet recording apparatus of the first aspect, the ink in the ink liquid chamber is pressurized through the vibration plate by the displacement of the electromechanical transducer to eject the ink droplet from the nozzle. Equipped with an ink-jet head, and the diaphragm of this head is electrically grounded, so that metal ions in the diaphragm are prevented from flowing out into the ink to make holes, and the reliability of the diaphragm is improved. And the image quality is improved.

According to the ink jet recording apparatus of claim 2, in the ink jet recording apparatus of claim 1,
The inkjet head has an electrically grounded nozzle cover, and the diaphragm is electrically connected to the nozzle cover, so that the diaphragms of a plurality of heads can be collectively grounded, thereby improving productivity. .

According to the ink jet recording apparatus of claim 3, in the ink jet recording apparatus of claim 1,
A conductive pattern that is electrically grounded is formed on the insulating substrate on which the electromechanical transducer is disposed, and the diaphragm is electrically connected to the conductive pattern. Reliability can be ensured for each head.

According to a fourth aspect of the present invention, there is provided an ink jet head which presses ink in an ink liquid chamber through a vibration plate by a displacement of an electromechanical transducer to discharge ink droplets from the nozzles. Since the forming member and the diaphragm are electrically connected, the elution of the diaphragm is prevented even if a metal piece contacts the nozzle forming member and a potential difference is generated between the diaphragm and the nozzle forming member. it can.

According to the ink jet head of the fifth aspect, the ink jet head of the fourth aspect is provided with the nozzle cover which is electrically grounded, and the nozzle cover and the nozzle forming member are electrically connected. In addition, the liquid chamber components that come into contact with the inks of the plurality of heads can be made to have the same potential difference, and are in an electrically stable state, so that elution of the diaphragm and the nozzle forming member can be prevented, and reliability is improved.

According to the ink jet head of claim 6, in the ink jet head of claim 4, a conductive pattern that is electrically grounded is formed on the insulating substrate on which the electromechanical transducer is provided, and Since the diaphragm is electrically connected, the diaphragm and the nozzle forming member can be reliably grounded by the head alone, and elution of the diaphragm and the nozzle forming member can be prevented, thereby improving reliability.

According to the ink jet head of the seventh aspect, in the ink jet head of the fourth aspect, the nozzle forming member and the vibrating plate are in a state of being electrically floating while being in a conductive state, so that it is inexpensive and The liquid chamber portion can be easily floated, the elution of the diaphragm and the nozzle forming member can be prevented, and the reliability is improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing an example of an inkjet head to which the present invention is applied.

FIG. 2 is an enlarged sectional view of a main part of the head in a direction orthogonal to a channel direction.

FIG. 3 is an enlarged sectional view of a main part of the head in a channel direction.

FIG. 4 is a sectional view of a main part showing a first embodiment of the present invention.

FIG. 5 is a perspective view of the embodiment.

FIG. 6 is an explanatory diagram illustrating a relationship between a driving waveform and an induced voltage.

FIG. 7 is an essential part perspective view showing a second embodiment of the present invention.

FIG. 8 is an essential part perspective view showing a third embodiment of the present invention.

FIG. 9 is a sectional view of a main part showing a fourth embodiment of the present invention.

FIG. 10 is a sectional view of a main part showing a fifth embodiment of the present invention.

FIG. 11 is a sectional view of a main part showing a sixth embodiment of the present invention.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 drive unit, 2 liquid chamber unit, 3 nozzle cover, 11 substrate, 12 piezoelectric element, 13 frame member, 32 liquid chamber partition member, 33 nozzle plate, 42
... Vibration plate, 53 ... FPC cable, 65 ... GND pattern, 66 parts ... Groove, 67 ... Hole part, 68 ... Conductive adhesive, 7
1, 72, 75 to 77: through holes, 73, 78: conductive adhesive.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Seiji Nagaba 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Inventor Masayuki Iwase 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company, Ltd. (72) Inventor Hideyuki Makita 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company (72) Inventor Tsutomu Sasaki 1-3-6, Nakamagome, Ota-ku, Tokyo Inside Ricoh Company

Claims (7)

[Claims] 1. An ink jet recording apparatus having an ink jet head for discharging ink droplets from nozzles by pressurizing ink in an ink liquid chamber through a vibration plate by displacement of an electromechanical transducer, wherein the vibration plate of the ink jet head is An ink jet recording apparatus, which is electrically grounded. 2. An ink jet recording apparatus according to claim 1, wherein said ink jet head is provided with an electrically grounded nozzle cover, and said diaphragm is electrically connected to said nozzle cover. Recording device. 3. The ink jet recording apparatus according to claim 1, wherein a conductive pattern that is electrically grounded is formed on an insulating substrate on which the electromechanical transducer is provided, and the diaphragm is electrically connected to the conductive pattern. An ink jet recording apparatus, wherein the ink jet recording apparatus is electrically connected. 4. An ink jet head that presses ink in an ink liquid chamber through a vibrating plate by a displacement of an electromechanical transducer to discharge ink droplets from a nozzle, wherein a nozzle forming member having the nozzle and the vibrating plate are provided. An ink-jet head, wherein is electrically connected. 5. The ink jet head according to claim 4, further comprising an electrically grounded nozzle cover, wherein said nozzle cover and said nozzle forming member are electrically connected. 6. The ink jet head according to claim 4, wherein an electrically grounded conductive pattern is formed on the insulating substrate on which the electromechanical transducer is provided, and the diaphragm is electrically connected to the conductive pattern. An inkjet head, characterized in that it is connected to an ink jet head. 7. The ink jet head according to claim 4, wherein said nozzle forming member and said diaphragm are in a state of being electrically floating while being in a conductive state.