JPH0858089A - Ink jet recording device - Google Patents

Abstract

PURPOSE: To provide a highly reliable ink jet head which ensures an easy removal of air bubbles from its flow passage. CONSTITUTION: An ink feed restriction hole 4 is disposed on the outer side of a pressure chamber 5 when seen from the laminate direction of a base plate and is formed near the one end of a feed communication passage 38 and the other end thereof is laid on and connected to the end of the pressure chamber 5 when seen from the laminate direction of the base plate, whereby the ink feed restriction hole 4 is so arranged as to avoid its directly opposite position with respect to the pressure chamber 5 by the feed communication passage 38.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-demand type ink jet recording apparatus for ejecting ink droplets when receiving print data and forming dots on recording paper by the ink droplets.

[0002]

2. Description of the Related Art An on-demand type ink jet recording apparatus which ejects ink droplets from a plurality of nozzles in accordance with input information and outputs characters and figures has a low noise, a low running cost and a high print quality on plain paper or recycled paper. It is superior to other systems in that it allows recording and writing.

As this ink jet recording apparatus, FIG.
The prior art shown in No. 3 is disclosed in Japanese Patent Application Laid-Open No. 6-40030. As shown below, this inkjet head is configured by laminating a plurality of plates each having a different function. That is, the pressure chamber forming substrate 32 that defines the elongated pressure chambers 5 arranged in a plane is sealed on one surface thereof with the vibration plate 33 having the piezoelectric elements 34 arranged corresponding to the pressure chambers 5. , The other surface is a communication channel 38, 3
The pressure chamber 5 is covered with a sealing substrate 43 having 9 to form pressure chambers 5 that are individually partitioned to generate a pressure necessary for ejecting ink droplets. Further, an ink supply diaphragm forming substrate 43 having the ink supply diaphragm 4 is laminated on the sealing substrate 31, and the ink reservoir chamber 6 and the communication passage 38 formed by perforating the ink reservoir chamber forming substrate 42 laminated on this substrate. Restricts ink flow to and from.

Since this conventional ink jet recording apparatus has a structure in which the substrates are laminated, it can be easily manufactured. In particular, even when the actuator portion is formed by integrally firing the ceramics, the sealing property of the ink flow path between the joining members is improved. Since it can be secured easily and stably, it is possible to provide an inkjet recording apparatus having high mass productivity and high reliability.

In such an ink jet head, when air bubbles stay in the ink flow path, the air bubbles hinder the ink supply or absorb the pressure for ejecting the ink, causing defective ink ejection. Such bubbles may remain in the ink flow path when the ink is first filled from the ink tank that supplies ink, or may enter from the connection part with the ink tank when the ink tank is replaced due to ink consumption, Since the ink meniscus of the nozzle is destroyed by vibration or the like and enters from the nozzle, the ink jet recording apparatus must be provided with a means for discharging the bubbles. Generally, a method of installing a pump in an ink jet recording apparatus and driving the pump to forcibly discharge ink from the nozzle when replacing an ink tank or when an ink ejection failure occurs, and removing bubbles in the flow at that time To be taken.

However, in the conventional ink jet recording apparatus, at the portion where the ink is ejected from the narrow opening of the ink supply diaphragm to the communication flow path portion, the stagnation of the ink flow occurs at the corner of the communication flow path portion, and the ink discharging force of the pump The air bubbles cannot be discharged even if the value is raised. Such a stagnation part may become very large due to an assembly error when stacking and joining the substrates. For example, in the flow path structure shown in FIG.
In the flow channel structure shown in FIG. 15, stagnation occurs in the D section and the E section, which significantly reduces the manufacturing yield of the inkjet head.

In an ink jet head having a low bubble discharging property, a pump must be used to strongly discharge the ink for a long time, and the ink is wasted and the printing cost becomes high.

[0008]

SUMMARY OF THE INVENTION The present invention is intended to solve such problems, and its object is to provide a pressure chamber, a supply communication passage, an ink supply throttle, and an ink reservoir chamber in this order. By providing a flow channel structure that can easily discharge bubbles in the ink channels arranged in a stack, defective ink ejection due to retention of bubbles does not occur, and unnecessary ink consumption is unnecessary, highly reliable inkjet recording It is to provide a device.

It is another object of the present invention to provide an ink jet recording apparatus having a high yield which does not deteriorate the bubble discharge property even if there is an assembly error.

[0010]

In order to solve the above problems, an ink jet recording apparatus according to the present invention comprises a pressure chamber having pressure generating means for pressurizing ink, a supply communication passage, an ink supply throttle, and an ink reservoir chamber. And are stacked in order,
In an ink jet recording apparatus having ink channels connected to each other, an ink supply diaphragm is arranged outside the pressure chamber when viewed from the stacking direction and connected near one end of the supply communication passage, and the other end of the supply communication passage is connected. When viewed from the stacking direction, the portion is overlapped with the end of the pressure chamber and connected to the pressure chamber, and the ink supply throttle is arranged so as not to face the pressure chamber across the supply communication passage.

[0011]

When the ink is discharged from the nozzle, the jet flow ejected from the ink supply throttle to the supply communication passage generates a vortex between the jet surface and the opposing wall surface. This vortex becomes larger as the distance from the ink supply diaphragm to the opposite wall surface becomes longer. Also,
If there is a structural step at the portion where this vortex is generated, bubbles will remain and cannot be ejected even if the ink flow rate is increased.
By making the supply communication path long and connecting the flow paths to both ends of the supply communication path so that the opening of the ink supply throttle and the pressure chamber do not face each other, it is possible to reduce the vortex and eliminate the structural step. it can. Therefore, a smooth flow is created from the ink supply throttle to the pressure chamber, and the flow path allows bubbles to be easily discharged.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings by embodiments.

FIG. 1 shows an ink jet recording apparatus 1 according to the present invention.
It is a perspective view showing an example of. In FIG. 1, the inkjet head cartridge 2 is positioned and fixed on a carriage 80, and the carriage 80 can be moved by a carriage motor 81 in the direction of arrow A, which is the main scanning direction. A recording medium 82 such as printing paper is wound around a platen 83 and can be moved by a paper feed motor 84 in the direction of arrow B, which is the sub-scanning direction. The inkjet head cartridge 2 mounted on the carriage 80 moves in the main scanning direction, ejects ink droplets according to a print signal, and combines with the movement of the recording medium in the sub scanning direction to form an image in a two-dimensional plane. To form. Also,
If printing is not performed for a certain period of time or more, the printer moves to the standby position 86 where the ink suction means 85 is located. The ink suction unit 85 has a cap 87 and a cap advancing / retreating mechanism (not shown), and can realize a state in which the cap 87 is in contact with the ink ejection surface of the inkjet head cartridge 2 and a state in which the cap 87 is not in contact. it can. If new ink is introduced into the inkjet head due to the replacement of the ink cartridge, or if defective ink ejection occurs,
The ink in the inkjet head is sucked by using this ink suction means, and the air bubbles in the inkjet and the deteriorated ink that cause ejection failure are discharged from the nozzle.

FIG. 2 is a sectional view of the ink jet head cartridge 2. In FIG. 2, the inkjet head cartridge 2 includes a head unit 10 and a fixing member 20.
And an ink storage unit 70. The head unit 10 is positioned on the fixing member 20 and joined by an adhesive. The ink storage portion 70 is fixed to the fixing member 20 by inserting the ink introduction passage 21 of the fixing member 20 into the ink discharging portion 72. Ink introduction path 21
The fitting of the ink discharge part 72 and the ink discharge part 72 is sealed by an O-ring 71. The ink stored in the ink storage portion 70 is supplied to the head unit 10 through the ink introduction passage 21 of the fixing member 20. The ink containing portion 70 contains a porous body 74 therein, and the porous body 74 is impregnated with ink. The porous body 74 is preferably a foam material made of a material that is not attacked by the ink and does not deteriorate the ink. In addition, a communication hole 76 covered with a breathable film 77 is provided on the surface of the ink storage portion 70 facing the ink discharge portion 72, so that the internal pressure is reduced to the ink consumption amount while suppressing the evaporation of the ink. Regardless of the atmospheric pressure.

In this embodiment, the ink jet head cartridge 2 is integrally joined, and only the ink containing portion cannot be replaced. However, the ink introducing passage 2
Filter 75 to prevent foreign matter from entering 1
Alternatively, the ink storage unit 70 can be replaced by providing a structure that prevents ink from leaking from the ink discharge unit to the outside.

Further, the ink storage portion is not mounted on the carriage, but the ink storage portion is provided at a fixed position in the ink jet recording apparatus, and a flexible tube is connected between the ink storage portion and the ink jet head which reciprocates together with the carriage. Is also possible.

FIG. 3 shows an ink jet head 1 of the present invention.
FIG. 3 is an external perspective view of 0 viewed from the nozzle plate side. Further, FIG. 4 is an external perspective view of the head unit 10 as viewed from the fixing member side. The head unit 10 is configured by laminating a plate-shaped actuator unit 30 and a plate-shaped flow path unit 40 having a sufficient area for mounting the actuator unit 30 on the surface. Wiring means 26 for applying a drive signal to the pressure generating element is connected to one surface of the actuator unit 30.

A more detailed structure of the head unit of the present invention will be described with reference to FIG. For the sake of explanation, FIG. 5 is shown by disassembling each component and changing relative dimensions.

The actuator unit 30 and the flow path unit 40 are each formed by laminating a plurality of plates.

First, the actuator unit 30 will be described. The actuator unit 30 is configured by sequentially stacking a sealing substrate 31, a pressure chamber forming substrate 32, and a vibrating plate 33. In addition, on the vibrating plate 33, each pressure chamber 5
Is formed on the lower electrode 35, and pressure generating means corresponding to each pressure chamber 5 is formed on the lower electrode 35. The pressure generating means of the present embodiment comprises a piezoelectric element 34, and the upper electrode 36 is sandwiched between the plurality of piezoelectric elements 34 so as to sandwich the piezoelectric element 34 with the lower electrode 35 in order to supply a driving voltage to the piezoelectric element 34. Is formed. That is, an individual drive signal for selectively driving the individual piezoelectric element 34 is applied to the lower electrode 35. Upper electrode 36 which is a common electrode and lower electrode 35 which is an individual electrode
Is connected to the external drive circuit by connecting the connection terminal 37 formed on the vibration plate 33 and the flexible printed circuit (FPC) 26. The pressure chambers 5 for generating the ink pressure necessary for ejecting ink droplets are arranged in a plane by the through holes formed in the pressure chamber forming substrate 32, and the peripheries of the through holes serve as side walls to be divided into a plurality of pressure chambers. Has been done. The sealing substrate 31 is hermetically bonded to the side wall to form a pressure chamber bottom wall so as to seal the pressure chamber 5. In this sealing substrate 31, a long and narrow supply communication passage 38 for supplying ink from the outside of the actuator unit for each pressure chamber and a nozzle communication passage 39 for connecting to the nozzle 3 for ejecting ink droplets are bored. Each pressure chamber 5 is connected to the nozzle communication passage 39 near one end, and is connected to one end of the supply communication passage 38 at the other end.

Next, the flow channel unit 40 will be described. The flow path unit 40 is configured by sequentially stacking a nozzle plate 41, a reservoir chamber forming substrate 42, and an ink supply diaphragm forming substrate 43. A through hole that defines the reservoir chamber 6 is formed in the reservoir chamber forming substrate 42. One of the through holes is the nozzle plate 41 and the other is the ink supply diaphragm forming substrate 4.
By sealing with 3, the reservoir chamber 6 is configured. The reservoir chamber 6 has a function as a manifold for branching the ink from the ink storage portion into the pressure chambers, and is planarly overlapped with the actuator unit 30 from a portion that planarly overlaps with the supply communication passages 38 when viewed from the substrate surface. It is formed over the part that does not overlap. In the reservoir chamber 6, the ink supply aperture forming substrate 43 is provided with an ink supply aperture 4 which connects the reservoir chamber 6 and one end of each of the elongated supply communication passages 38.
A reservoir port 8 for guiding the ink from the ink storage portion to the reservoir chamber 6 is formed in the ink supply aperture forming substrate 43 in a portion that does not overlap with 0 in a plane. In addition, the nozzle 3 that ejects ink droplets is attached to the nozzle plate 41 by the pressure chamber 5.
Has been perforated. In order to connect the nozzle 3 and the corresponding pressure chamber 5, the ink supply aperture forming substrate 43
On the reservoir chamber forming substrate 42, nozzle communication passages 44 and 45 are formed corresponding to the nozzles 3.

In this embodiment, two rows of pressure chambers 5 facing one actuator unit 30 are formed,
They are arranged so as to be offset from each other by ½ of the pressure chamber arrangement interval in the arrangement direction. Corresponding nozzles 3 are also arranged in two rows, offset from each other by one half of the nozzle arrangement interval. Therefore, the nozzle arrangement interval seen from the main scanning direction A is one half of the pressure chamber interval, doubling the substantial nozzle density.

The ink supply apertures 4 and the nozzle communication passages 44, which are opened on one surface of the flow passage unit 40, have a one-to-one correspondence with the supply communication passages 3 of the actuator unit 30.
8 is formed at a position overlapping the nozzle communication path 39,
The actuator unit 30 on the flow path unit 40,
By overlapping and joining the corresponding openings, the flow paths between both units are connected.

Next, a more detailed structure of the flow path unit 40 will be described below. The nozzle plate 41 made of a stainless steel plate having a thickness of 50 to 150 μm has an opening diameter of 30 to 5
The taper nozzle 3 of 0 μm has an interval of 564 μm in the row.
So, it is formed in two rows. The reservoir forming substrate 42 is formed by punching out a stainless steel plate having a thickness of 150 μm.
And the nozzle communication passage 45 are formed. The diameter of the nozzle communication passage 45 is preferably about 150 μm, which is the same as the plate material. The ink supply aperture forming substrate 43 is 50 to 150 μm.
The ink supply diaphragm 4 and the nozzle communication passage 44 are punched in a stainless steel plate. In the ink supply throttle 4, the ink flow generated by the pressure in the pressure chamber is restricted from escaping to the reservoir chamber 6 side and efficiently directed to the nozzle 3 side.
It is preferable to set the impedance equal to or larger than the fluid impedance of the nozzle. In this embodiment, the nozzle 3 has the same size as the nozzle 3 and is bored so that the cross section has a taper portion that expands in the thickness direction. Since the taper is used, the diameter of the narrowest part can be made smaller than the plate thickness, and it is possible to form the part with high accuracy. The diameter of the nozzle communication passage 44 is set to be equal to or slightly larger than the nozzle communication passage 45 of the reservoir chamber forming substrate 42 and smaller than the width of the pressure chamber 5, and in this embodiment, it is set to 150 to 300 μm. By setting in this way, it is possible to prevent bubbles from staying in the flow path from the pressure chamber 5 to the nozzle 3. These three plates are stacked so that the through holes associated with each other communicate with each other. For the joining between the plates, brazing, diffusion joining, an adhesive, a die-cut adhesive sheet, or the like can be used. Here, an adhesive made of an epoxy resin that is not corroded by ink is used. For each plate, all stainless steel plates were used in this example, but if the material is not corroded by ink, ceramics, inorganic materials such as glass, silicon, metal materials such as nickel, polyimide, polycarbonate, polysulfone, etc. It is also possible to appropriately select and combine the above plastic materials. Further, as a processing method suitable for each material, in addition to etching and removal processing methods such as laser processing using a YAG laser, a carbon dioxide gas laser, an excimer laser, etc.,
A method of directly forming a shape such as an electroforming method or resin molding can also be adopted.

For example, since the nozzle plate 41 and the ink supply diaphragm forming substrate 43 are relatively thin and the holes to be formed must be small in diameter and must be formed with high accuracy, a method of processing a plastic plate with an excimer laser is used. Alternatively, a method of electroforming nickel is also suitable.

Next, a more detailed structure of the actuator unit 30 will be described below. The pressure chamber forming substrate 32 is a fired body of zirconia having a thickness of 150 μm, and includes a plurality of pressure chambers 5.
Are formed in two rows with an in-row spacing of 564 μm as in the nozzle 3. The width of the pressure chamber 5 is 350 to 450 μm
And the length is 1 to 3 mm. These dimensions are optimally designed according to the required ink drop weight, nozzle array density, and the like. The sealing substrate 31 is a fired body of zirconia having a thickness of 150 μm, and one side wall of the pressure chamber 5 is sealed and bonded. The nozzle communication path 39 of the sealing substrate 31 was formed with a diameter of 300 μm. The supply passage has a width of 200 μm and a length of 3
It was formed in a long hole of 00 μm to 1 mm. The vibrating plate 33 is a sintered body of zirconia having a thickness of 10 to 20 μm,
The other side wall is sealed and joined. On the lower electrode 35 formed on the vibration plate 33 corresponding to the pressure chamber 5, the width is 80 to 90% of the width of the pressure chamber 5, and the thickness is 20 to 40 μm.
m of piezoelectric zirconate titanate is laminated. Further, instead of zirconia, alumina, aluminum nitride, lead zirconate titanate, or the like can be used.

In this embodiment, these are integrally formed by firing as follows. That is, FIG. 12 (A)
In the state of a green sheet, which is a ceramic material, a vibration plate 33, a pressure chamber forming substrate 32 formed by punching a through hole that determines the pressure chamber 5 in advance, and a sealing substrate 31 formed by punching a communication passage in advance. Pressurized, then 800
Baking together at a temperature of ℃ to 1000 ℃. Next, FIG.
In (B), as the lower electrode 35, a material containing at least one of platinum, palladium, silver-palladium, silver-platinum, and platinum-palladium as a main component is formed in a portion corresponding to the pressure chamber 5 by printing. And bake. Further, in FIG. 12 (C), the piezoelectric material 34 is similarly formed by printing and is fired to finish the actuator unit integrally,
Finally, a common electrode made of chromium, gold, nickel, copper or the like is formed on the plurality of piezoelectric elements by sputtering to form a common electrode. In the actuator thus formed by integral firing, the pressure chamber forming substrate 32 having a very fine structure and the thin vibration plate 33 are firmly joined by firing, so that the ink sealing property and the ink corrosion resistance are excellent. In addition, there is an advantage that the manufacturing process thereof is extremely simple because it is sufficient to apply a paste electrode or a piezoelectric element by a printing technique and to bake it. The sealing substrate 31 has a feature that the joint area with the flow path unit can be increased, and thus the ink can be easily sealed at the connection portion of both units. In particular, when the actuator unit 30 is formed by integrally firing ceramics, it has a feature that the airtightness of the pressure chamber 5 can be sufficiently ensured as described above.

The above-mentioned method of integrally forming by firing is very excellent, but as in the conventional method, a method of joining substrates made of metal or resin by adhesion, welding or fusion,
The actuator unit can be formed by combining a method of processing glass or a silicon substrate by etching, a method of forming by plastic molding, a method of mounting a chip-shaped piezoelectric element on a diaphragm, and the like.

Next, a cross-sectional view of the flow path configuration of the head unit 10 including the flow path unit 40 and the actuator unit 30 and the ink flow along the elongated pressure chamber, and a plan view showing the overlapping state of the flow path contours. This will be described using 7.
The ink guided from the ink storage unit is supplied to the pressure chamber 5 via the reservoir port 8, the ink reservoir chamber 6, the ink supply throttle 4, and the supply communication passage 38. The ink supply force is forced from the outside of the inkjet head by using the ink suction means 85 when the ink is first filled into the flow path or when air bubbles, dust, or modified ink having an increased viscosity is present in the flow path. Is given to you. Further, when the inkjet head is in operation, it is given by the capillary force of the meniscus formed in the nozzle 3. Piezoelectric element 34 as a pressure generating element
In the present embodiment using the piezoelectric element 34 and the vibration plate 33, a unimorph actuator is configured.
The piezoelectric element 34 contracts in the in-plane direction by applying a voltage to
The vibrating plate 33 bends and deforms in a direction of contracting the pressure chamber 5. The fluid pressure generated at this time generates an ink flow from the pressure chamber 5 through the nozzle communication paths 39, 44, and 45 to the nozzle 3, and an ink droplet is ejected from the nozzle opening.

The ink supply aperture 4 is, as shown in FIG.
It is arranged on the outer side in the longitudinal direction of the pressure chamber 5 and opens to the lower wall of one end of the elongated supply communication passage 38. Therefore, when the ink is discharged using the ink suction means 85, the ink jet flow that has flowed into the supply communication passage from the ink supply throttle 4 is the upper wall of the supply communication passage that faces the ink supply throttle 4, that is, the pressure chamber forming substrate. It collides with the surface, changes its direction toward the other end of the supply communication passage, that is, the connection portion with the pressure chamber end, and flows along the supply communication passage. With the configuration of the present invention, the ink jet flow smoothly changes its direction without generating a large vortex in the supply communication passage, and the stepped portion that creates the stagnation of the flow is structurally eliminated, so that no bubbles are retained. Became. However, depending on the length of the supply communication passage 38, it is predicted that bubbles may stay at the pressure chamber side end portion F of the supply communication passage.
Therefore, as shown in FIG. 8, the dimension L of the supply communication passage 38 is
By changing 1 and L2, it was observed whether bubbles stayed at the end F. A glass diaphragm was used to allow observation. The ink supply aperture has a minimum diameter of 30 μm, a cylindrical length of 20 μm, a taper taper angle of 35 ° in all angles, and an ink supply aperture total length (substrate thickness) of 60 μm. is there. Other dimensions of the supply communication passage are as follows: width 200 μm, height (substrate thickness + adhesive layer thickness) 180 μm
m.

When the bubbles were intentionally retained and it was confirmed by experiments whether the bubbles could be discharged by using the ink suction means, the following results were obtained.

[0032]

[Table 1]

In the above table, x indicates an embodiment in which bubbles could not be discharged, Δ indicates an example in which some bubbles could be discharged,
◯ is an example in which bubbles were completely discharged. From this result, the dimension L1 is important, and by making this dimension equal to or larger than the dimension (180 μm) of the cross section of the flow path, the flow of the supply communication passage is not biased to the pressure chamber forming substrate side, and the ink supply It was confirmed that the flow was evenly distributed on the side of the aperture forming substrate.

Next, another embodiment of the present invention will be described with reference to FIGS.
0, shown in FIG.

As shown in FIG. 9, in this embodiment, the ink supply aperture forming substrate 43 is provided with two ink supply apertures 104 and 105 for each supply communication passage (each pressure chamber). As shown in the cross-sectional view of FIG. 10, the first ink supply throttle 104 is arranged on the outer side in the longitudinal direction of the pressure chamber 5 as in the previous embodiment, and the lower wall of one end of the elongated supply communication passage 38 is formed. It is open to. In addition, the second ink supply diaphragm 105
11, the pressure chamber 5 and the opening of the supply communication passage 38 are arranged so as to overlap with each other and open at the end portion which connects them to each other. Therefore, the second ink supply throttle 10 is provided.
5 is opposed to the end of the pressure chamber 5 with the supply communication passage 38 interposed therebetween. By providing the second ink supply diaphragm 105, it is possible to easily discharge the bubbles in the F portion and the G portion in FIG. 10, and it is possible to restore the ink jet recording apparatus to a normal state with a smaller ink discharge amount. Became. Further, as a side effect of the present embodiment, the flow on the ink reservoir chamber 6 side is dispersed to the two ink supply throttles,
The ink flow becomes uniform, and the bubble discharging property of the ink reservoir chamber 6 is improved.

In the ink supply throttle, as described above, the ink flow generated by the pressure in the pressure chamber is changed to the reservoir chamber 6
It has the role of limiting the escape to the side and efficiently directing it to the nozzle 3 side. Therefore, if two ink supply diaphragms are arranged, the flow toward the nozzle side is reduced, and the efficiency is lowered, for example, the driving voltage must be increased. In order to effectively discharge the bubbles without lowering the efficiency, the flow flowing from the second ink supply throttle 105 to be smaller than the flow flowing from the first ink supply throttle 104 to the pressure chamber 5. It turned out to be effective. The flow from the second ink supply throttle 105 generates a vortex at the connection portion between the supply communication passage 38 and the pressure chamber 5, so that the excessive flow adversely deteriorates the bubble discharge property. Therefore, the fluid resistance of the second ink supply throttle 105 is made larger than the fluid resistance of the first ink supply throttle 104 so that the flow rate is less than the flow rate from the first ink supply throttle 104, preferably about half. It is effective to do. Since the fluid resistance is approximately inversely proportional to the fourth power of the diameter of the minimum portion of the ink supply throttle, the diameter of the minimum portion of the first ink supply throttle 104 is 35 μm,
By setting the diameter of the minimum portion of the ink supply diaphragm 105 to 30 μm, the ink flow rates of both inks can be set to 2: 1.

Further, it is important to reduce the generation of vortices in order to effectively discharge the bubbles with a small ink flow. For that purpose, the taper direction of the second ink supply diaphragm 105 is communicated. It has become clear that it is preferable to take it in a direction that spreads toward the supply path 38.

[0038]

As described above, in the present invention, the ink supply throttle is arranged outside the pressure chamber when viewed from the stacking direction and is connected near one end of the supply communication passage, and the other of the supply communication passages is connected. The end portion of the ink is overlapped with the end of the pressure chamber when viewed from the stacking direction and connected to the pressure chamber, and the ink supply throttle is arranged so as not to face the pressure chamber across the supply communication passage. It has become possible to provide an economical inkjet recording apparatus which can reliably discharge air bubbles in the flow path to, and is highly reliable and does not waste ink.
Further, it is possible to provide an ink jet recording apparatus with a high production yield, in which a step portion that causes stagnation of ink is eliminated in the flow path, and manufacturing reliability such as stacking position error does not significantly reduce reliability. Became.

Further, by disposing the second ink supply throttle at a position facing the pressure chamber with the supply communication passage interposed therebetween,
It has an effect that the dischargeability of bubbles can be enhanced as much as possible.

[Brief description of drawings]

FIG. 1 is a perspective view showing an entire inkjet recording apparatus of the present invention.

FIG. 2 is a cross-sectional view showing the entire inkjet head of the present invention.

FIG. 3 is a perspective view showing a head unit of the present invention.

FIG. 4 is a perspective view showing a head unit of the present invention.

FIG. 5 is an exploded perspective view illustrating the internal structure of the inkjet head of the present invention.

FIG. 6 is a cross-sectional view illustrating an ink flow path of the inkjet head of the present invention.

FIG. 7 is a plan view illustrating an ink flow path of the inkjet head of the present invention.

FIG. 8 is a cross-sectional view illustrating an ink flow path of the inkjet head of the present invention.

FIG. 9 is an exploded perspective view illustrating the internal structure of the inkjet head of the present invention.

FIG. 10 is a cross-sectional view illustrating an ink flow path of the inkjet head of the present invention.

FIG. 11 is a plan view illustrating an ink flow path of the inkjet head of the present invention.

FIG. 12 is a drawing for explaining the manufacturing method of the actuator unit of the present invention.

FIG. 13 is a cross-sectional view illustrating the structure of a conventional inkjet head.

FIG. 14 is a cross-sectional view illustrating the structure of a conventional inkjet head.

FIG. 15 is a cross-sectional view illustrating the structure of a conventional inkjet head.

[Explanation of symbols]

 2 Inkjet head cartridge 3 Nozzle 4 Ink supply throttle 5 Pressure chamber 6 Reservoir chamber 8 Reservoir port 10 Head unit 30 Actuator unit 31 Sealing substrate 32 Pressure chamber forming substrate 33 Vibrating plate 34 Piezoelectric element 38 Supply communication passage 39 Nozzle communication passage 40 Flow Channel unit 41 nozzle plate 42 reservoir chamber forming substrate 43 ink supply diaphragm forming substrate 44, 45 nozzle communication passage

Claims (7)

[Claims] 1. An ink jet recording apparatus in which a pressure chamber having a pressure generating means for pressurizing ink, a supply communication passage, an ink supply throttle, and an ink reservoir chamber are sequentially stacked and an ink flow path connected to each other is formed. In the above, the ink supply throttle is arranged outside the pressure chamber when viewed from the stacking direction and connected near one end of the supply communication passage, and the other end of the supply communication passage is viewed from the stacking direction. An ink jet recording apparatus, characterized in that the ink supply throttle is disposed so as to overlap an end portion of a pressure chamber and connected to the pressure chamber, and the ink supply diaphragm is not opposed to the pressure chamber across the supply communication passage. 2. The supply communication passage and the ink supply diaphragm are defined as cavities formed in a sealing substrate and an ink supply diaphragm forming substrate, respectively, and these substrates are sequentially laminated on the pressure chamber. The ink jet recording apparatus according to claim 1, wherein the ink flow path is formed by the above. 3. The pressure chamber is configured as a ceramic body in which a pressure chamber forming substrate having a vibration plate and a window for partitioning the pressure chamber and the sealing substrate are laminated with a green sheet and integrally fired, and the vibration plate. 3. An ink jet recording apparatus according to claim 2, wherein a pressure generating means composed of a piezoelectric element is provided on the outer surface of the sheet, corresponding to the pressure chamber. 4. The length of the supply communication passage from the connection position with the ink supply throttle to the connection position with the pressure chamber is equal to or larger than the dimension of the cross section of the supply communication passage. The ink jet recording apparatus according to claim 1, which is characterized in that. 5. A second ink supply diaphragm, comprising:
2. The ink jet recording apparatus according to claim 1, wherein the ink supply throttle is disposed at a position facing the pressure chamber across the supply communication passage. 6. The ink jet recording apparatus according to claim 5, wherein a fluid resistance of the second ink supply diaphragm is set to be larger than a fluid resistance of the ink supply diaphragm (first ink supply diaphragm). 7. The ink jet recording apparatus according to claim 5, wherein the second ink supply diaphragm has a taper portion, and the taper portion extends in the supply communication passage side.