JP2001162791A - Ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording head in which ink can be refilled quickly after an ink drop is ejected even if the nozzle density is increased and occurrence of adjacent crosstalk can be prevented. SOLUTION: The cavity of a pressure generating chamber 4 in a channel substrate 5 comprises a section 21 penetrating a channel forming substrate in the thickness direction at an end part on the side opposite to an ink supply opening 14, and a shallow groove part 23 having a bottom part 22 on the nozzle plate 3 side. A deep groove part 24 is formed along the longitudinal direction of the pressure generating chamber at the central part in the widthwise direction on the bottom of the shallow groove part while communicating, at one end thereof, with the penetrating section.

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 head used in an ink jet printer or an ink jet plotter.

[0002]

2. Description of the Related Art In a conventional recording head, a nozzle plate is provided on one surface of a flow path substrate in which a plurality of pressure generating chambers are provided and a common ink chamber or the like communicating with each pressure generating chamber is formed. The flow path unit is formed by joining the diaphragms, and the flow path unit is joined to the head case, and a pressure fluctuation is generated in the pressure generating chamber through the diaphragm by the pressure generating element provided in the head case. To eject ink droplets from the nozzle openings. The pressure generating chamber requires a predetermined volume, and must be formed corresponding to the nozzle openings opened corresponding to the dot formation density, so that the pressure generating chamber is orthogonal to the arrangement direction of the nozzle openings. It is formed as a chamber that is long in the direction.

In order to form the pressure generating chamber, a single crystal silicon plate used as a flow path substrate is formed by etching. Specifically, it is formed as an elongated through hole penetrating from one surface to the other surface, that is, penetrating in the thickness direction of the flow path substrate, or only a tip portion directly communicating with the nozzle opening is formed as a through hole. Between the through-hole and the common ink chamber side, the silicon plate on the nozzle plate side is left as a shallow groove part that is partially removed in the thickness of the silicon plate, and the through-hole and the shallow groove part constitute a pressure generating chamber. .

[0004]

By the way, in order to respond to miniaturization and high density, it is necessary to increase the nozzle density. However, when the nozzle density is increased, the partition wall between the pressure generating chambers becomes thinner. The partition walls are easily deformed by the ink pressure at the time of ejection. Therefore, so-called adjacent crosstalk occurs in which the ejection characteristics of ink droplets differ depending on whether or not the adjacent nozzle openings eject. If the partition is lowered to suppress the adjacent crosstalk and the partition is hardly deformed, the thickness of the pressure generating chamber also becomes thin, so that the flow resistance of the pressure generating chamber increases. When the flow path resistance increases, refilling of the ink after the ejection of the ink droplet is delayed, and the response is reduced due to the influence of the meniscus movement.

[0005] Therefore, the present invention, even if the nozzle density is increased,
An object of the present invention is to provide an ink jet recording head capable of speeding up refilling of ink after ejecting ink droplets and preventing occurrence of adjacent crosstalk.

[0006]

Means for Solving the Problems The present invention has been proposed to achieve the above-mentioned object. According to the first aspect of the present invention, a plurality of elongated cavities serving as pressure generating chambers are arranged with a partition wall interposed therebetween. A flow path substrate that is arranged and forms an empty space that becomes a common ink chamber, and forms an ink supply port that communicates the empty space for the common ink chamber and one end of the empty space for the pressure generating chamber; A sealing plate joined to one surface of the flow path substrate and closing one opening of the empty space, and a nozzle plate joined to the other surface of the flow path substrate and having a nozzle opening corresponding to the pressure generating chamber. Are stacked to form a flow path unit, which has a pressure generating element, and discharges ink droplets from nozzle openings by pressure fluctuations in the pressure generating chamber. Flow path at the end opposite to the supply port Consisting of a penetrating portion penetrating in the thickness direction of the substrate, and a shallow groove having a bottom on the nozzle plate side, a deep groove is formed in the center of the bottom of the shallow groove in the width direction along the longitudinal direction of the pressure generating chamber. And an end of the deep groove communicates with the penetrating portion.

According to a second aspect of the present invention, the deep groove portion includes:
2. The ink jet recording head according to claim 1, wherein the ink jet recording head is formed to a depth reaching the nozzle plate through the bottom of the shallow groove.

According to a third aspect of the present invention, the deep groove portion is
2. The ink jet recording head according to claim 1, wherein the ink jet recording head is formed to have a depth halfway through the thickness of the bottom of the shallow groove.

According to a fourth aspect of the present invention, the deep groove portion is
4. The ink jet recording head according to claim 3, wherein the recording head comprises a groove whose depth increases as approaching the penetrating portion.

According to a fifth aspect of the present invention, the width of the deep groove is two thirds or less of the width of the shallow groove. Head.

According to a sixth aspect of the present invention, the front-rear width of the penetrating portion is at least half the width of the pressure generating chamber, and
The inkjet recording head according to any one of claims 1 to 5, wherein the number is twice or less.

According to a seventh aspect of the present invention, the flow path substrate is a plate member in which at least an upper portion of the penetrating portion and a through-hole portion forming a shallow groove portion are formed in series, and a bottom portion of the shallow groove portion, and at least a middle portion of the penetrating portion. 2. The ink jet recording head according to claim 1, wherein a plate material having a through-hole formed as a deep groove portion and a plate material forming a bottom of the deep groove portion and having a through-hole formed at least below the through portion are laminated. 3. is there.

According to another aspect of the present invention, the flow path substrate has a plate member in which at least an upper half of a penetrating portion and a through-hole portion forming a shallow groove portion are formed in series, and a bottom portion of the shallow groove portion. 3. The ink jet recording head according to claim 2, wherein a lower half and a plate material having a through-hole portion serving as a deep groove portion are laminated.

According to a ninth aspect of the present invention, there is provided an ink jet recording head according to the seventh or eighth aspect, wherein each of the plate members is formed of a metal plate, and each of the cavities is formed by press punching. .

According to a tenth aspect of the present invention, there is provided an ink jet recording head according to the seventh or eighth aspect, wherein each of the plate members is formed of a metal plate, and each of the voids is formed by etching.

According to an eleventh aspect of the present invention, in the channel substrate, a through portion, a shallow groove portion, and a deep groove portion are formed by etching one of a metal plate and a silicon plate three times. The inkjet recording head according to claim 1 or 3, wherein:

According to a twelfth aspect of the present invention, in the flow path substrate, a through-hole, a shallow groove, and a deep groove are formed by etching a silicon single crystal plate twice. An inkjet recording head according to claim 4.

According to a thirteenth aspect of the present invention, in the ink jet recording head according to any one of the first to thirteenth aspects, at least a part of the sealing plate is a vibrating plate which can be elastically deformed. It is.

According to a fourteenth aspect of the present invention, there is provided the ink jet recording head according to any one of the first to thirteenth aspects, wherein the pressure generating element is a piezoelectric element.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of an ink jet recording head (hereinafter, referred to as a recording head 1), and FIG.
FIG. 2 is a sectional view of a main part of the recording head 1. To manufacture the recording head 1, a nozzle plate 3 having a plurality of rows of nozzle openings 2, a flow path substrate 5 having pressure generating chambers 4 communicating with each of the nozzle openings 2, and a pressure generating chamber 4. Are formed in an island shape, and a vibrating plate (elastic plate) 6 also functioning as a sealing plate is laminated in this order to form a flow path unit 7.
Are superimposed on the head case 11 on which the pressure generating elements 10 are supported.
Then, the edge cover 12 is put on the nozzle plate 3 side by contacting and bonding to the respective vibration regions (island portions).

The nozzle plate 3 is formed by forming nozzle openings 2 having a diameter of 20 μm to 30 μm on a thin plate such as a stainless plate at a pitch corresponding to the dot formation density.
The flow path substrate 5 is a silicon substrate having a thickness of about 400 μm in which a space is formed by wet etching or the like.
3, an ink supply port 14 and a pressure generation chamber 4 which are formed to be elongated from the common ink chamber 13 to a position overlapping the nozzle opening 2 of the nozzle plate 3. The flow path substrate 5 will be described later in detail.

The diaphragm 6 is made of a metal plate 6a such as a stainless steel plate.
A stainless steel portion is left as an island-shaped vibrating region (island portion) 6c in a region overlapping with the pressure generating chamber 4 with respect to the composite plate composed of the resin film 6b and the vibrating region 6c.
Only the resin film is left around. An ink supply hole 15 is formed in the vibration plate 6 in a region overlapping the common ink chamber 13.

The head case 11 is provided with a window 16 at the distal end surface thereof. Inside the head case 11, a plurality of comb-shaped pressure-generating elements 10 fixed at the base end to a fixed substrate 17 are provided. Is inserted, the tip of the pressure generating element 10 enters the inside of the window 16. The head case 11
Is formed with an ink supply pipe 19.

In the recording head 1 configured as described above, when a voltage pulse is applied to the pressure generating element 10, the pressure generating element 10 bends, that is, contracts in a direction of expanding the volume of the pressure generating chamber 4, and A negative pressure is generated in the generation chamber 4. As a result, the meniscus of the ink is drawn into the nozzle opening 2, and the ink flows from the common ink chamber 13 into each of the pressure generating chambers 4 through each of the ink supply ports 14. On the other hand, when a discharge pulse is applied, the pressure generating element 10 bends, that is, expands, in a direction to contract the volume of the pressure generating chamber 4, and a positive pressure is generated in the pressure generating chamber 4. As a result, ink droplets are ejected from the nozzle openings 2. In all of these operations, the expansion and contraction of the pressure generating element 10 are transmitted through the vibration area 6c of the diaphragm 6.

Next, the flow path substrate 5, particularly the structure of the pressure generating chamber 4, will be described in detail. In the first embodiment of the pressure generating chambers 4 shown in FIG. 3, the pressure generating chambers 4 which are long in the direction orthogonal to the arrangement direction of the nozzle openings 2 correspond to the pitch of the nozzle openings 2 with a partition wall 20 interposed therebetween. And an ink supply port 14 having a width smaller than the width of the pressure generation chamber 4 is formed between one end of the pressure generation chamber 4 and the common ink chamber 13 so as to communicate with each other. At the other end of the pressure generating chamber 4 which is located on the opposite side to the nozzle opening 2 and penetrates in the thickness direction of the flow path substrate 5, a through portion 21 is opened. A shallow groove portion 23 having a bottom portion 22 is formed on the nozzle plate 3 side, and a deep groove portion 24 is formed in the widthwise central portion of the bottom portion 22 of the shallow groove portion 23 along the longitudinal direction of the pressure generating chamber 4. With
One end of the deep groove portion 24 communicates with the through portion 21. Then, the above-described penetrating portion 21, shallow groove portion 23, and deep groove portion 24 form the pressure generating chamber 4.

The penetrating portion 21 is provided with a front-rear width FBW and a flow path width (width of the pressure generating chamber 4) in order to prevent residual air bubbles at the time of cleaning, particularly air bubbles from remaining at corners on the diaphragm 6 side. It is set to be equal to or more than half of W and equal to or less than twice. The depth of the deep groove 24 is two-thirds of the width of the shallow groove 23 in a range from the vicinity of the outlet of the ink supply port 14 to the penetrating part 21.
It is formed with the following width and a depth halfway through the thickness of the bottom portion 22 of the shallow groove portion 23. In short, in the present embodiment, the deep groove 24 does not reach the nozzle plate 3.

To give an example of specific dimensions, the flow path substrate 5
Has a thickness of 200 to 1000 μm (for example, 400 μm).
μm), the depth of the shallow groove 23 is in the range of 30 to 200 μm (for example, 80 μm), and the width of the pressure generating chamber 4 is 50 μm.
The width of the deep groove 24 is in the range of 20 to 50 μm (for example, 40 μm).
Set to. In this case, the thickness of the partition 20 is 10
５０50 μm (for example, 30 μm).

The pressure generating chamber 4 having such a deep groove 24
In order to manufacture the flow path substrate 5, the first plate member 5a having the upper portion of the penetrating portion 21, the shallow groove portion 23, the ink supply port 14, and the penetrating empty portion to be the upper portion of the common ink chamber 13, and the shallow groove portion 23
The second plate member 5 having a through hole which is a bottom portion of the through hole 21 and a middle portion of the through portion 21, the deep groove portion 24, and the middle portion of the common ink chamber 13.
b, and a third opening of a through space below the through portion 21
The plate members 5c may be laminated in this order. In this case, by using a silicon wafer or a thin metal plate such as a stainless steel plate for each of the plate members 5a, 5b, and 5c, the through-hole portion is formed by punching by press working, or formed by etching and then laminated. Is also good. Alternatively, each void may be formed by etching a single silicon plate a plurality of times. For example, after a pilot hole is formed in a portion to be the penetrating portion 21 with a laser beam, the penetrating portion 21 is formed by a first etching process, and then a shallow groove portion 23 is formed by a second etching process. The deep groove portion 24 may be formed by a second etching process.

In the pressure generating chamber 4 having the above-described structure, the height of the partition wall 20 is reduced to prevent the partition wall 20 from being deformed.
3) Even if the channel resistance of the shallow groove portion 23 alone becomes high due to thinning, the deep groove portion 2 formed in the bottom portion 22 of the shallow groove portion 23
4, the flow resistance of the entire pressure generating chamber 4 can be reduced. Therefore, the flow path resistance of the pressure generating chamber 4 can be reduced, the ink can be quickly refilled after ejecting the ink droplets, and the responsiveness can be improved. In addition, since the height is reduced, the partition walls 20 are hardly deformed, so that adjacent crosstalk can be prevented. In addition,
Even if the deep groove portion 24 is formed in the bottom portion 22 of the shallow groove portion 23, since the deep groove portion 24 is formed in the central portion of the bottom portion 22, there is no possibility that the strength of the partition wall 20 is reduced. In addition,
The width of the pressure generating chamber 4 on the vibration plate 6 side is desirably wide in order to efficiently transmit the deformation of the piezoelectric element to the pressure generating chamber 4 side. In this respect, the present invention does not cause any problem.

In the second embodiment of the pressure generating chamber 4 shown in FIG. 4, the nozzle plate 3 extends through the bottom 22 of the shallow groove 23.
The feature is that the deep groove portion 24 is formed at a depth reaching the maximum depth, and the other configuration is the same as that of the first embodiment.

The pressure generating chamber 4 having such a deep groove portion 24
In order to manufacture the flow path substrate 5, a fourth plate member 5 d having a through-hole which becomes the upper half of the penetrating portion 21, the shallow groove 23, the ink supply port 14, and the upper half of the common ink chamber 13 is formed. Alternatively, the fifth plate member 5e having the bottom half of the shallow groove 23, the lower half of the penetrating part 21, the deep groove 24, and the through-hole formed as the lower half of the common ink chamber 13 may be laminated. In this case, each plate 5
By using a silicon wafer or a thin metal plate such as a stainless steel plate for d and 5e, the through portion 21 may be formed by stamping out by press working, or may be formed by etching and then laminated. Alternatively, each void may be formed by etching a single silicon plate twice. For example, after forming a pilot hole in a portion to be the penetrating portion 21 with a laser beam, the penetrating portion 21 and the deep groove portion 24 are formed by the first etching process, and then the shallow groove portion 23 is formed by the second etching process. It may be formed.

In the pressure generating chamber 4 having such a configuration, not only the effect of the first embodiment is obtained, but also the flow channel resistance is further increased because the deep groove portion 24 is deeper than the first embodiment. Can be reduced. Therefore, the ink filling after the ink droplet ejection can be performed more quickly, and the responsiveness can be further improved.

The third embodiment of the pressure generating chamber 4 shown in FIG. 5 is characterized in that the deep groove portion 24 is constituted by a groove whose depth increases as approaching the penetrating portion 21. Is similar to that of the first embodiment.

As described above, the pressure generating chamber 4 having the deep groove portion 24 whose bottom is inclined can be manufactured by etching a silicon single crystal plate twice. That is, when the silicon plate is etched, the portion to be removed is inclined due to the directionality of the silicon. Therefore, by utilizing this characteristic, the deep groove 24 having the inclined bottom surface can be formed.

As described above, the formation of the deep groove portion 24 having an inclined bottom surface makes it possible to make use of the characteristics of the etching process as described above, thereby facilitating the manufacture. Is increased, the conversion in the ink flow direction is also performed smoothly.

In the above-described embodiment, the piezoelectric element is described as the pressure generating element 10. However, the pressure generating means in the present invention is not limited to this. Any configuration may be used as long as it can be generated. For example, a magnetostrictive element or a heating element may be used.

[0037]

As described above, according to the present invention, the following effects can be obtained. That is, according to the present invention, the empty portion of the pressure generating chamber is constituted by a penetrating portion penetrating in the thickness direction of the flow path forming substrate, and a shallow groove portion having a bottom portion on the nozzle plate side. In the central portion in the width direction, a deep groove is formed along the longitudinal direction of the pressure generating chamber, and one end of the deep groove communicates with the through portion, so that the height of the partition wall between the pressure generating chambers is reduced. The occurrence of adjacent crosstalk can be prevented, and even if the height of the partition walls is reduced, the flow chamber resistance in the pressure generation chamber is reduced by the deep groove formed at the bottom of the shallow groove, even if the pressure generation chamber becomes thinner Can be done. Therefore, the ink can be quickly replenished after the ejection of the ink droplets, and the responsiveness can be improved.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a recording head.

FIG. 2 is a sectional view of a main part of the recording head.

3A and 3B are enlarged explanatory views of a first embodiment of a pressure generation chamber of a flow path substrate, wherein FIG. 3A is a plan view of an enlarged part of the pressure generation chamber, and FIG. 3B is a pressure generation chamber of FIG. FIG. 3C is an enlarged view of the XX section, and FIG. 3C is a YY sectional view of the pressure generating chamber of FIG.

FIG. 4A is an enlarged partial plan view of a second embodiment of a pressure generating chamber in which a deep groove reaching a nozzle plate is formed, and FIG. 4B is an XX of the pressure generating chamber of FIG. The figure which expanded and showed the cross section, (c) is YY sectional drawing of the pressure generation chamber of (a).

FIG. 5 is a cross-sectional view of a main part of a third embodiment of a pressure generating chamber in which a deep groove portion whose bottom surface is inclined downward toward a through portion is formed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Recording head 2 Nozzle opening 3 Nozzle plate 4 Pressure generating chamber 5 Flow path substrate 6 Vibrating plate (elastic plate) 7 Flow path unit 10 Pressure generating element 11 Head case 12 Edge cover 13 Common ink chamber 14 Ink supply port 15 Ink supply hole DESCRIPTION OF SYMBOLS 16 Window part 17 Fixed substrate 19 Ink supply pipe 20 Partition wall 21 Penetration part of pressure generation chamber 22 Bottom part of shallow groove part 23 Shallow groove part 24 Deep groove part

Claims (14)

[Claims] A plurality of elongated cavities serving as pressure generating chambers are arranged side by side with a partition wall therebetween, and a vacant space serving as a common ink chamber is formed. The vacant space for the common ink chamber and the vacant space for the pressure generating chamber are provided. A flow path substrate formed with an ink supply port communicating with one end of the section, a sealing plate joined to one surface of the flow path substrate to close one opening of the empty space, and the other of the flow path substrate And a nozzle plate having a nozzle opening corresponding to the pressure generating chamber, and a flow path unit formed by laminating the nozzle plate and a pressure generating element. In the ink jet recording head that ejects ink droplets, the empty space of the pressure generating chamber has a penetrating portion penetrating in the thickness direction of the flow path forming substrate at an end opposite to the ink supply port, and a bottom portion on the nozzle plate side. And a shallow groove having The widthwise central portion of the bottom of the shallow groove portion, an ink jet recording head with the longitudinal direction of the pressure generating chamber forms a deep groove portion, characterized in that one end of the deep groove portion communicating with the through portion. 2. The ink jet recording head according to claim 1, wherein the deep groove is formed to a depth reaching the nozzle plate through the bottom of the shallow groove. 3. The ink jet recording head according to claim 1, wherein the deep groove portion is formed at a depth halfway through the thickness of the bottom of the shallow groove portion. 4. The ink jet recording head according to claim 3, wherein the deep groove portion is formed by a groove whose depth increases as approaching the penetrating portion. 5. The ink jet recording head according to claim 1, wherein the width of the deep groove is not more than two thirds of the width of the shallow groove. 6. The ink-jet apparatus according to claim 1, wherein the front-rear width of the penetrating portion is equal to or more than half the width of the pressure generating chamber and equal to or less than twice the width. Type recording head. 7. The flow path substrate has a plate material in which at least an upper portion of a penetrating portion and a through-hole portion serving as a shallow groove portion are formed in series, and a through-hole portion serving as a bottom portion of the shallow groove portion and serving as at least a middle portion and a deep groove portion of the penetrating portion. Plate material and the bottom of the deep groove,
2. The ink jet type recording head according to claim 1, wherein a plate material having at least a through hole formed under the through portion is laminated. 8. The flow path substrate, wherein a plate material in which at least an upper half portion of a penetrating portion and a through-hole portion serving as a shallow groove portion are formed in series,
3. The ink jet recording head according to claim 2, wherein a plate material forming a bottom portion of the shallow groove portion, at least a lower half portion of the penetrating portion, and a through-hole portion forming a deep groove portion is laminated. 9. The ink jet recording head according to claim 7, wherein each of the plate members is formed of a metal plate, and each of the cavities is formed by press punching. 10. The ink jet recording head according to claim 7, wherein each of said plate members is formed of a metal plate, and each of said vacant portions is formed by etching. 11. The channel substrate according to claim 1, wherein a through portion, a shallow groove portion and a deep groove portion are formed by etching one of a metal plate and a silicon plate three times. Or an inkjet recording head according to 3. 12. The channel substrate according to claim 4, wherein a through-hole, a shallow groove, and a deep groove are formed by etching a silicon single crystal plate in two steps.
3. The ink jet recording head according to item 1. 13. The ink jet recording head according to claim 1, wherein at least a part of the sealing plate is a vibrating plate that can be elastically deformed. 14. The ink jet recording head according to claim 1, wherein the pressure generating element is a piezoelectric element.