JP2005349667A - Liquid jet head and liquid jet device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an ejection velocity of a liquid droplet from being lowered, thereby eliminating variation in density. <P>SOLUTION: This liquid jet head comprises a plurality of heating elements 12 arranged in one direction, a barrier layer 13, a partition wall 13a which is formed of a part of the barrier layer 13, provided to each portion between the heating elements 12 by being extended in a direction perpendicular to the arrangement direction of the heating elements 12 and allows a liquid to flow into a side of the heating element 12 from both sides in a direction perpendicular to the arrangement direction of the heating elements 12, a pair of side walls 13b each of which is formed of a part of the barrier layer 13 to be parallel to the partition wall 13a at the outside thereof, and a rear wall 13c which is formed of a part of the barrier layer 13 by being provided along the arrangement direction of the heating elements 12. A common fluid channel 23 is provided to the heating elements 12 at the opposite side of the rear wall 13c so that the liquid can be supplied to the side of the heating elements 12 from the side of the common fluid channel 23 and the opposite side thereof (a side of a rear common fluid channel 24). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermal liquid discharge head used in an ink jet printer and the like, and a liquid discharge device such as an ink jet printer including the liquid discharge head. The present invention relates to a technology that realizes a flow path structure without discharge unevenness.

Conventionally, for example, in a liquid discharge head used in a liquid discharge apparatus typified by an ink jet printer, a thermal method that uses expansion and contraction of generated bubbles, and a piezo method that uses fluctuations in the shape and volume of a liquid chamber, It has been known.
In the thermal method, a heating element is provided on a semiconductor substrate, bubbles are generated in the liquid in the liquid chamber by the heating element, and the liquid is ejected as droplets from a nozzle disposed on the heating element to be used as a recording medium. It ’s what makes you land.

FIG. 10 is an external perspective view showing a conventional liquid discharge head 1 of this type (hereinafter simply referred to as the head 1). In FIG. 10, the nozzle sheet 17 is bonded onto the barrier layer 3, and the nozzle sheet 17 is shown in an exploded manner.
FIG. 11 is a cross-sectional view showing the flow path structure of the head 1 of FIG. Note that this type of flow path structure of the liquid ejection device is disclosed in, for example, Patent Document 1.
JP 2003-136737 A

  10 and 11, a plurality of heating elements 12 are arranged on the semiconductor substrate 11. In addition, the barrier layer 3 and the nozzle sheet 17 are sequentially stacked on the semiconductor substrate 11. Here, the one in which the heat generating element 12 is formed on the semiconductor substrate 11 and the barrier layer 3 is formed thereon is referred to as a head chip 1a. And what the nozzle sheet | seat 17 was bonded together on the head chip | tip 1a is called the head 1. FIG.

  The nozzle sheet 17 has nozzles 18 arranged so that nozzles (holes for discharging droplets) 18 are positioned on the respective heat generating elements 12. In addition, the barrier layer 3 is provided on the semiconductor substrate 11 so as to be interposed between the heating element 12 and the nozzle 18 to form a liquid chamber 3 a between the heating element 12 and the nozzle 18. .

  As shown in FIG. 10, the barrier layer 3 is formed in a substantially comb-like shape so as to surround three sides of each heating element 12 in a plan view, so that the liquid chamber in which only one side is opened is formed. 3a is formed. This opened portion forms an individual flow path 3 d and communicates with the common flow path 23.

  The heating elements 12 are arranged in the vicinity of one side of the semiconductor substrate 11. In FIG. 11, the dummy chip D is arranged on the left side of the semiconductor substrate 11 (head chip 1a), so that one side surface of the semiconductor substrate 11 (head chip 1a) and one side surface of the dummy chip D are arranged. The common flow path 23 is formed. In addition, as long as it is a member which can form the common flow path 23, not only the dummy chip D but any member may be used.

  Furthermore, as shown in FIG. 11, a flow path plate 22 is disposed on the surface of the semiconductor substrate 11 opposite to the surface on which the heating elements 12 are provided. As shown in FIG. 11, the flow path plate 22 is formed with an ink supply port 22a and a supply flow path 24 having a substantially concave cross section so as to communicate with the ink supply port 22a. The supply channel 24 and the common channel 23 communicate with each other.

  Thus, the ink is sent from the ink supply port 22a to the supply flow path 24 and the common flow path 23, and enters the liquid chamber 3a through the individual flow path 3d. When the heat generating element 12 is heated, bubbles are generated on the heat generating element 12 in the liquid chamber 3a, and a part of the liquid in the liquid chamber 3a is used as a droplet by the flying force when the bubbles are generated. 18 is discharged.

  In FIGS. 10 and 11, the actual shape is ignored and the shape is exaggerated for easy understanding. For example, the thickness of the semiconductor substrate 11 is about 600 to 650 μm, and the thickness of the nozzle sheet 17 and the barrier layer 3 is about 10 to 20 μm.

In the conventional head 1 described above, firstly, there is a problem that dust and dust enter the flow path and the nozzle 18, resulting in ejection failure at the nozzle 18 and insufficient supply of liquid in the flow path.
Here, garbage and dust drift in the general space and move freely. Therefore, they fall into the liquid and exist as dust and dust in the liquid. However, since the liquid ejection apparatus such as an ink jet printer has a structure in which liquid is ejected from the nozzle 18 in units of microns, there is a possibility that dust or dust may be clogged in the nozzle 18.

For this reason, at present, in the manufacturing process, for example, parts are washed with a dust or a liquid with little dust in a working environment such as a dust-free chamber.
Furthermore, in terms of design, it is necessary to provide filters for removing dust and dust at a plurality of locations in the flow path of the liquid ejection device.
In particular, as the number of nozzles increases as in a line head, there is a higher probability that ejection failure of the nozzles 18 will occur, so there is a problem that stricter management is required and costs increase.

Secondly, as a result of the temperature of the head 1 increasing, bubbles may be generated in the liquid, and there is a problem that the amount of discharge becomes insufficient due to the bubbles.
Examples of the locations where bubbles are generated include the common flow path 23 and the individual flow paths 3d described above, but they may cause discharge unevenness regardless of where they are generated.

FIG. 12 is a diagram showing a result of taking a picture of a state in which bubbles remain in the common channel 23. In FIG. 12, the nozzle sheet 17 is formed from a transparent body so that the state of the internal bubbles can be seen.
In FIG. 12, a filter is provided in the common flow path 23. This filter is provided in order to prevent dust and dust from entering the individual flow path 3 d, and has columnar columns arranged along the common flow path 23.

As shown in FIG. 12, in the area where bubbles remain in the common flow path 23 (area surrounded by a dotted line in FIG. 12), the amount of liquid supplied to the individual flow path 3d decreases. As a result, the discharge amount of the liquid is reduced and appears as discharge unevenness in which the density is reduced in a relatively wide range.
Note that the discharge state is affected when bubbles are present. The discharge itself is affected by the reaction generated by the pressure generated during discharge and the liquid near the liquid chamber 3a, the barrier layer 3, and the presence of bubbles. This is probably because of this.

In addition, bubbles may enter the vicinity of the inlet of the individual flow path 3d or the individual flow path 3d. FIG. 13 is a diagram illustrating a result of taking a photograph of a state in which bubbles remain at the inlet of the individual flow path 3d. In FIG. 13, the nozzle sheet 17 is formed from a transparent body, as in FIG.
In such a case, even if the bubbles are small, the influence is great because the bubbles are present in a narrow space. That is, the discharge amount is smaller than in the case of FIG. Further, since only the discharge amount from the nozzle 18 corresponding to the individual flow path 3d into which bubbles have entered decreases, it becomes noticeable as a streak.

  Once the bubbles as described above are generated, even if the discharge is repeated, the bubbles stick to the common flow path 23 and the individual flow paths 3d or simply reciprocate between the individual flow paths 3d and the common flow path 23. Does not disappear. In addition, since the liquid is supplied into the liquid chamber 3a so as to pass through between the bubbles, a state where the ejection characteristics are insufficient often remains fixed.

In addition, since it is confirmed that the bubbles disappear when the discharge operation is stopped and the temperature of the liquid is lowered after being left for a long time, the bubbles in this case It can be seen that the slight amount of gas present in is formed by thermal expansion.
On the other hand, since the portion covered with bubbles is a gas, the thermal conductivity is poor, and the cooling by the liquid does not proceed, so the heat of the heat generating portion tends to accumulate. As a result, there is a problem that bubbles expand.

  Further, since bubbles tend to be generated particularly when the centers of the heating element 12 and the nozzle 18 are shifted, the bubbles generated on the heating element 12 may remain effectively without being used for ejection. Conceivable.

Further, the bubbles may enter the liquid chamber 3a or the nozzle 18. FIG. 14 is a diagram showing a result of taking a picture of a state in which gas has entered the liquid chamber 3a from the nozzle 18. As shown in FIG.
In FIG. 14, a filter (in which triangular columns are arranged unlike in FIG. 12) is provided in the common flow path 23, and the coalesced bubbles block between the columns of the filter, and the liquid is liquid. This is a state where it cannot move to the chamber 3a side.

  When the movement of the liquid from the common flow path 23 to the liquid chamber 3a side is blocked by bubbles, the meniscus balance of the nozzle 18 is likely to be destroyed. In such a state, the shock wave from the adjacent nozzle 18 is triggered, and the gas enters the liquid chamber 3a from the nozzle 18. That is, since the pressure of the internal liquid is set to be lower than the atmospheric pressure, when the equilibrium state of the meniscus is destroyed, the liquid moves backward toward the common flow path 23 and cannot be discharged.

Thirdly, there is a problem that unevenness of discharge is caused by a shock wave at the time of discharge, particularly in combination with the presence of bubbles. In the thermal method, the pressure change during ejection is considerably larger than that in the piezo method.
There are the following two problems caused by the discharge impact.

  First, the shock wave triggers the drawing of bubbles from the adjacent liquid chamber 3a. In order to avoid this problem, it is conceivable to increase the distance between the filter columns. However, in such a case, dust and dust passing through the filter become large, and the individual flow path 3d. It becomes easy for large garbage and dust to enter.

  The second problem is that the shock wave propagates to the neighboring nozzles 18 and the meniscus vibrates to cause discharge unevenness. When bubbles are generated or residual bubbles are present, the shock wave and the bubbles are mixed with each other, the bubbles are likely to be drawn in, and ejection irregularities are likely to appear.

  By the way, in the case of a serial method in which dots can be superimposed to form an image (overwriting), even if there are about one to two nozzles that cause ejection unevenness, It is possible to repair the discharge unevenness so as not to be noticeable. On the other hand, in the case of a line method in which image formation is completed by one droplet ejection and, as a rule, overwriting cannot be performed, the presence of ejection unevenness is a fatal wound.

  Note that the inventors of the present invention are a previously undisclosed application that has a flow path structure that is less likely to cause a flow path failure due to dust, dust, and the like, and that has as little influence as possible from bubbles, and that has almost no discharge unevenness. It has already been proposed by application 2004-056006.

However, after further investigation, it became clear that the following problems exist in practice.
In the above technique, the discharge speed is slightly lower than the previous discharge speed (the one that was about 10 m / s is about 7 to 8 m / s). The cut is insufficient.

On the other hand, the inventors of the present invention have developed a technique related to deflected discharge of droplets disclosed in Japanese Patent Application Laid-Open No. 2004-1364. However, when such deflected discharge is performed, the speed reduction becomes more remarkable. . This is because a plurality of heat generating elements are provided in one liquid chamber, and the plurality of heat generating elements generate bubbles with a time difference, so that the general method of generating bubbles only on one heat generating element is used. This is because the discharge pressure is lowered.
When such a decrease in the discharge speed occurs, there is a problem that density unevenness may occur in the printing result, although it is not uneven discharge.

Further, when the discharge speed is lowered, depending on the wet state around the orifice, it is pulled by the surface tension of the remaining droplets, and the amount remaining on the nozzle sheet increases.
In particular, in the case of a line head, compared to a serial head, the time for continuous printing without cleaning the ejection surface is long and the amount of printing is large, so that it remains on the nozzle surface, particularly around the orifice. The amount of liquid increases and interferes with newly ejected droplets.

  Therefore, the problem to be solved by the present invention is based on the above undisclosed prior application technique (Japanese Patent Application No. 2004-0560006), and by making improvements to this technique so that the droplet discharge speed does not decrease. It is to improve density unevenness.

The present invention solves the above-described problems by the following means.
The invention of claim 1, which is one of the present invention, is provided on a semiconductor substrate, a plurality of heating elements arranged along one direction, a nozzle layer in which nozzles located on the heating elements are formed, The barrier layer provided between the semiconductor substrate and the nozzle layer and a part of the barrier layer are disposed between the heating elements and perpendicular to the arrangement direction of the heating elements. A partition that extends in the direction and allows liquid to flow into the heating element side from both sides in a direction perpendicular to the arrangement direction of the heating elements, and a part of the barrier layer, and N (N is An integer greater than or equal to 2) the heating elements and the (N-1) partition walls are formed by a pair of side walls provided in parallel to the partition walls and a part of the barrier layer. Installed along the direction of arrangement of the heating elements. And 0 ≦ y <x, where x is an interval between the partition wall and the rear wall, and y is an interval between the side wall and the rear wall, and the N heating elements. The liquid discharge unit includes the (N-1) partition walls, the pair of side walls, and the rear wall, and a common flow path is provided on the side opposite to the rear wall with respect to the heating element, The liquid discharge head is characterized in that liquid is supplied from the common flow path side and the opposite side to the heating element side of the liquid discharge unit.

(Function)
In the above invention, a liquid discharge unit including N heat generating elements, (N-1) partition walls, side walls on both sides, and a rear wall is provided. At least in the liquid discharge unit, the heat generating elements are provided from both sides by the partition walls. Liquid can flow in. Further, in the structure of the present invention, liquid can be supplied to the heating element from both sides. However, when such a priming function is provided, the pressure on the heating element (liquid chamber) tends to decrease. . However, since it is a closed structure as one liquid discharge unit, if an appropriate value is selected as the value of N, it is possible to eliminate the pressure drop and maintain the necessary pressure during liquid discharge.

  In addition, although the nozzle layer and the barrier layer are provided separately in the following embodiments (barrier layer 13 and nozzle sheet 17), both may be formed integrally. Alternatively, the barrier layer may be integrally formed on the semiconductor substrate.

  According to the present invention, it is possible to provide a priming function capable of supplying a liquid from both sides (two different directions) onto the heating element (liquid chamber), and at the same time, the discharge speed (pressure) of the droplet which tends to decrease. ) Is ensured, the occurrence of density unevenness can be reduced. Thereby, the bubble generation probability accompanying discharge can be reduced. In addition, the amount of liquid remaining in the nozzle sheet can be reduced. Furthermore, even when the above-described deflected discharge technique is used, a good discharge operation can be ensured.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The liquid ejection device according to the present invention is an ink jet printer (thermal color line printer; hereinafter simply referred to as a printer) in the embodiment, and the liquid ejection head is the line head 10 in the embodiment.

  FIG. 1 is an external perspective view showing a line head 10 of this embodiment. The line head 10 has four rows of head chips 19 in which head chips 19 are arranged in a line for the width of the A4 size photographic paper, arranged in four rows, and each row has Y (yellow), M (magenta), This is a four-color head of C (blue green) and K (black).

  The line head 10 is formed by arranging a plurality of head chips 19 side by side in a zigzag pattern and bonding the lower portions of these head chips 19 to a single nozzle sheet 17 (nozzle layer). Here, each nozzle 18 formed on the nozzle sheet 17 is located at a position corresponding to each heating element 12 (described later) of all the head chips 19 (specifically, the center axis of the heating element 12 and the center of the nozzle 18). Arranged so that the axis line coincides). In the following embodiment, each heat generating element 12 is composed of one heat generating element. However, the present invention is not limited to this. Each heating element 12 may be configured in a plurality of divided configurations such as a configuration divided into two (in the case of performing the above-described deflection discharge).

The head frame 16 is a support member that supports the nozzle sheet 17 and has a size corresponding to the nozzle sheet 17. Moreover, the length of each accommodation space 16a is matched with the lateral width (about 21 cm) of A4 size.
The four head chip 19 rows are arranged inside the housing space 16 a of the head frame 16 for each row. In addition, an ink tank that stores inks of different colors is attached to the storage space 16a of the head frame 16 on the back surface of the head chip 19, so that each storage space 16a, that is, each head chip 19 is mounted. Different colors of ink are supplied to the columns.

FIG. 2 is a plan view showing one head chip 19 row. In FIG. 2, the head chip 19 and the nozzle 18 are shown in an overlapping manner.
Each head chip 19 is arranged in a staggered manner, that is, adjacent head chips 19 are 180 degrees different from each other. As shown in FIG. 2, between the head chips 19 arranged at the “N−1” th and “N + 1” th and the head chips 19 arranged at the “N” th and “N + 2” th, A common flow path 23 for supplying ink to the head chip 19 is formed.
Further, as shown in FIG. 2, the intervals between the nozzles 18 are all equal, including the staggered adjacent portions.

  The above-described line head 10 is fixed in the printer main body, and the surface (ink landing surface) of the recording medium (printing paper) is the ink discharge surface (nozzle sheet) of the line head 10 with respect to the fixed line head 10. 17) and the recording medium is moved relative to the line head 10 while maintaining a predetermined gap. During this relative movement, ink is ejected from the nozzles 18 of the head chip 19 so that dots are arranged on the recording medium, whereby characters, images, and the like are printed in color.

  Next, the head chip 19 of this embodiment will be described in more detail. The head chip 19 is the same in that the heating elements 12 are arranged on the semiconductor substrate 11 as compared with the conventional head chip 1a. However, the shape of the barrier layer 13 provided on the semiconductor substrate 11 is different. The reason why the shape of the barrier layer 13 is different is that the shape of the peripheral portion of the heat generating element 12 (a partition wall 13a described later) and the shape from the common flow path 23 to the heat generating element 12 are different.

FIG. 3 is a plan view showing the shape of the barrier layer 13 of the head chip 19 according to the embodiment of the present invention.
As in the prior art, the heating elements 12 are arranged on the semiconductor substrate. In FIG. 2, a partition wall 13 a is disposed between the heating elements 12. The partition wall 13 a is formed by a part of the barrier layer 13, and is arranged so as to extend in a direction perpendicular to the arrangement direction of the heat generating elements 12. Further, the partition wall 13a is formed such that the thickness of both end portions in the longitudinal direction is thicker than that of the central portion. Accordingly, the interval W1 in the region on the heating element 12 (this region is referred to as “liquid chamber”) and the interval W2 at both ends are as follows:
W1> W2
It is formed so that it may become a relation.
Thereby, the portion of the interval W2 can provide a function as a dust / dust removal filter, and the internal (liquid chamber) pressure at the time of discharging a droplet can be increased.

  Further, (a pair of) side walls 13b are provided on both sides of the N heating elements 12 and the (N-1) partition walls 13a. In the example of FIG. 3, N = 2 (two heating elements 12 and one partition wall 13a disposed between the two heating elements 12). The side wall 13b is formed by a part of the barrier layer 13, and is disposed substantially parallel to the partition wall 13a. The shape on the common flow path 23 side is substantially the same as the partition wall 13a. In the example of FIG. And the partition 13a are formed with substantially the same distance to the end on the common flow path 23 side. Further, the side wall 13b and the partition wall 13a form a flow path from the common flow path 23 side toward the heating element 12.

Furthermore, a rear wall 13 c is formed by a part of the barrier layer 13 on the side opposite to the common flow path 23. The rear wall 13 c is formed along the arrangement direction of the heat generating elements 12.
In this case, the partition wall 13a and the rear wall 13c are spaced apart by an interval x. Thereby, the rear common flow path 24 is formed on the rear wall 13c side, and the liquid can be moved by the rear common flow path 24 on the two heat generating elements 12 separated by the partition wall 13a.

Further, the side wall 13b and the rear wall 13c are connected (in the example of FIG. 3). Accordingly, the heating element 12 (the left or right heating element 12 in FIG. 3) arranged outside the side wall 13b and the two heating elements 12 arranged inside the side wall 13b are connected to the rear common flow path. On the 24th side, the liquid cannot be moved.
As described above, the liquid can be moved in the rear common flow path 24 on the rear wall 13c side only inside the outer wall surrounded by the side wall 13b. In the embodiment of FIG. 3, the liquid can move between the two heat generating elements 12 (liquid chambers). However, as the number of the heat generating elements 12 in the pair of side walls 13 b increases, the liquid is increased on the heat generating elements 12. Can move.

If the rear wall 13c and the side wall 13b are connected, when the distance between the rear wall 13c side end of the side wall 13b and the rear wall 13c is y,
y = 0
It becomes.
However, in the present invention, it is sufficient that the interval y is shorter than the interval x, and the interval y is larger than 0, that is, a gap may be formed between the rear wall 13c side end of the side wall 13b and the rear wall 13c.
Therefore,
0 ≦ y <x
If it is good.

If formed in this way, at least between the heating elements 12 separated only by the partition wall 13a, the liquid can move through the rear common flow path 24 on the rear wall 13c side. Even if there is a gap between the side wall 13b and the rear wall 13c, a considerable resistance is involved in order for the liquid to move to the adjacent heating element 12 through the gap.
Here, the portion including the N heat generating elements 12, the (N-1) partition walls 13a, the pair of side walls 13b, and the rear wall 13c is referred to as a “liquid discharge unit”. In this embodiment, the liquid discharge units are arranged side by side on the semiconductor substrate.

FIG. 4 is a plan view showing the shape of the barrier layer 13 of the head chip 19 according to another embodiment of the present invention.
In the embodiment of FIG. 4, N = 3. That is, the three heat generating elements 12, the two partition walls 13a, the one side wall 13b provided on both sides thereof, and the rear wall 13c constitute a liquid discharge unit. Further, in the embodiment of FIG. 4, unlike the embodiment of FIG. 3, the distal ends of the partition walls 13a and the side walls 13b are not formed thick. When formed in this way, the tip of the partition wall 13a or the side wall 13b cannot have a filter function, but there is no particular problem if a filter or the like is separately provided on the common flow path 23 side.

  If formed as in the embodiment of FIG. 4, the liquid can move from the rear common flow path 24 side on the three heating elements 12 in one liquid discharge unit. However, since the side wall 13b exists on the heat generating element 12 further outside, the liquid cannot move.

  As shown in FIG. 4, a plurality of liquid ejection units are arranged side by side on the semiconductor substrate, but are formed so that the pitch (arrangement pitch) P of the heating elements 12 is the same between adjacent liquid ejection units. Has been. A pair of independent side walls 13b is not provided between the adjacent liquid discharge units for each liquid discharge unit, but one side wall 13b is also used between the adjacent liquid discharge units. It becomes. One liquid discharge unit and the adjacent liquid discharge unit are integrally formed continuously.

Further, although N = 3 in FIG. 4, N = 2 may be used as shown in FIG. That is, it is sufficient if N ≧ 2.
On the other hand, if the value of N is too large, the number of openings in one liquid discharge unit increases, leading to a drop in the discharge speed (discharge pressure) of the droplets, and consequently discharge unevenness. From the experimental results, it was found that good results were obtained up to N ≦ 8.
Therefore,
2 ≦ N ≦ 8
It becomes.

FIG. 5 is still another embodiment of the present invention, and is a plan view showing the shape of the barrier layer 13 of the head chip 19.
In this embodiment, N = 4. In this embodiment, first, the filter 25 is provided on the common flow path 23 side. The filter 25 has a plurality of columns 25a arranged at an equal pitch. Further, the filter 25 fulfills its function by the gap between the pillars 25a. The interval between the pillars 25a is formed to be narrower than the interval between the partition walls 13a or between the partition wall 13a and the side wall 13b. Has been.

  Furthermore, the common channel 23 side end of the side wall 13b is located on the side farther from the heating element 12 than the common channel 23 side end of the partition wall 13a (in other words, extends to the common channel 23 side). ). The end of the side wall 13 b on the common flow path 23 side is connected to the column 25 a of the filter 25. In this case, the pitch of the pillars 25a may be set so that the pillars 25a are always positioned on the extended line of the side wall 13b.

  In the embodiment of FIG. 5, the column 25a of the filter 25 is connected to the pair of side walls 13b, and one column 25a is disposed at the center. Since the columns 25a connected to the side walls 13b are also the columns 25a of the side walls 13b of the adjacent liquid discharge units, the number of the columns 25a connected to one side wall 13b in one liquid discharge unit is reduced to 0.5. The number of columns 25a in one liquid discharge unit is 2 (because 0.5 + 1 + 0.5). That is, in the embodiment of FIG. 5, the number (N) of the heating elements 12 is 4, the number of the partition walls 13a is 3, and the number of the pillars 25a is 2.

If the column 25 a and the side wall 13 b of the filter 25 are connected as in the embodiment of FIG. 5, the strength of the liquid discharge unit, particularly the barrier layer 13 can be enhanced simultaneously with the role of the filter 25.
The column 25a of the filter 25 does not necessarily have to be connected to the side wall 13b in this way, and the size is also arbitrary. However, the gap between the columns 25a needs to be narrower than the gap between the partition walls 13a or between the partition walls 13a and the side walls 13b. Furthermore, in the embodiment of FIG. 5, the column 25a is a rectangular column having a substantially rectangular cross section, but the present invention is not limited to this, and various shapes can be used.

Furthermore, although it is preferable to provide the filter 25, it is not always necessary to provide the filter 25. For example, as shown in FIG. 3, the partition 13a and the side wall 13b are formed by increasing the thickness of the common channel 23 side end. A narrow entrance to the heating element 12 (liquid chamber) is sufficient.
However, the provision of the filter 25 not only prevents entry of dust and dust, but also prevents the partition wall 13a (liquid chamber) from being crushed by the pressure when the head chip 19 is joined to the nozzle sheet 17. You can have it.

The structure shown in FIGS. 3 to 5 as described above is provided on a semiconductor substrate. FIG. 6 is a plan view showing a head chip 19 in which liquid discharge units are arranged side by side on the semiconductor substrate 11. FIG. 6 shows one head chip 19 (the same applies to FIGS. 7 and 8 below). The head chip 19 is the same as that shown in FIG.
In FIG. 6, liquid discharge units (unit units) are arranged in parallel on the outer edge of one side of the semiconductor substrate 11 to provide a unit row. In the drawing, a common channel 23 is provided on the liquid supply side, and liquid is supplied to each liquid discharge unit from the direction of the arrow in the drawing.

  FIG. 7 is a plan view showing another embodiment of the head chip 19. In the embodiment of FIG. 7, an example is shown in which liquid discharge units are provided in parallel on the outer edge portions of two opposite sides on the semiconductor substrate 11, and unit rows are provided. In the embodiment of FIG. 7, the liquid ejection units arranged in parallel at the outer edge portion of one side and the liquid ejection units arranged in parallel at the outer edge portion of the other side face each other. That is, on the semiconductor substrate 11, the central portions are mutually on the rear wall 13 c side. As shown in FIG. 7, liquid supply sides are provided on the left and right sides in the drawing, and common flow paths 23 are provided on these liquid supply sides, respectively. Supplied.

FIG. 8 is a plan view showing still another embodiment of the head chip 19.
In FIG. 8, a liquid supply hole (long hole) 11 a penetrating from the back surface side to the front surface side is formed in the semiconductor substrate 11. The liquid supply hole 11a communicates with an ink tank or the like (not shown). Then, the liquid discharge units are arranged in parallel along the liquid supply hole 11a to provide a unit row, and the unit rows are arranged to face both sides of the liquid supply hole 11a.

In this case, since the liquid supply hole 11a side is the common flow path 23 side, the liquid discharge units disposed on both sides of the liquid supply hole 11a face each other.
As described above, examples of providing the liquid discharge unit on the semiconductor substrate 11 include the forms shown in FIGS. 6 to 8 and various other forms, but any form may be used.

  FIG. 9 is a plan view showing a mask diagram of the head chip 19 actually manufactured. In FIG. 9, white lines are connection portions other than the barrier layer 13 disposed on the semiconductor substrate 11. In the head chip 19, the heating element 12 is divided into two in the arrangement direction in order to deflect and discharge the droplets.

  Further, although the heating elements 12 are arranged at a constant pitch in one direction, all the heating elements 12 are not arranged in a line (on a straight line), and the centers of adjacent heating elements 12 are perpendicular to the arrangement pitch direction. In such a direction, they are shifted by a predetermined interval (a real number greater than 0). This technique has already been proposed by the present inventors (Japanese Patent Application No. 2003-383232).

  As a result, the distance between the centers of the adjacent nozzles 18 is larger than the arrangement pitch of the heat generating elements 12, so that the deformation amount of the nozzle 18 and its peripheral region due to pressure fluctuations accompanying the discharge of the droplets is reduced, and the droplets The discharge amount and the discharge direction can be stabilized.

  In FIG. 9, as in the embodiment of FIG. 3, N = 2 (one liquid discharge unit is provided with two heating elements 12 and one partition wall 13 a). Furthermore, the partition wall 13a and the side wall 13b are formed such that a part of the thickness on the common flow path 23 side is thick. This provides a function as a filter. Other than that, it is the same as the embodiment of FIG.

It is an external appearance perspective view which shows the line head of this embodiment. It is a top view which shows one head chip row | line | column. FIG. 4 is a plan view showing the shape of the barrier layer of the head chip according to the embodiment of the present invention. FIG. 5 is a plan view showing a shape of a barrier layer of a head chip according to another embodiment of the present invention. FIG. 10 is a plan view showing the shape of a barrier layer of a head chip, which is still another embodiment of the present invention. It is a top view which shows embodiment of a head chip. It is a top view which shows other embodiment of a head chip. It is a top view which shows other embodiment of a head chip. It is a top view which shows the mask figure of the head chip actually manufactured. It is an external appearance perspective view which shows the conventional liquid discharge head. It is sectional drawing which shows the flow-path structure of the head of FIG. It is a figure which shows the result of having photographed the state in which the bubble remained in the common flow path. It is a figure which shows the result of having photographed the state in which the bubble remained at the entrance of the separate flow path. It is a figure which shows the result of having photographed the state which gas entered the liquid chamber from the nozzle.

Explanation of symbols

10 Line head (liquid discharge head)
DESCRIPTION OF SYMBOLS 11 Semiconductor substrate 12 Heating element 13 Barrier layer 13a Partition wall 13b Side wall 13c Rear wall 17 Nozzle sheet (nozzle layer)
18 Nozzle 19 Head chip 23 Common flow path 24 Rear common flow path 25 Filter 25a Column x Space between partition wall 13a and rear wall 13c y Space between side wall 13b and rear wall 13c W1 In a region (liquid chamber) on heating element 12 Interval between partition walls 13a W2 Interval between partition walls 13a at both ends in the longitudinal direction of partition wall 13a

Claims (12)

A heating element provided on a semiconductor substrate and arranged in a plurality along one direction;
A nozzle layer in which nozzles located on the heating elements are formed;
A barrier layer provided between the semiconductor substrate and the nozzle layer;
The barrier layer is formed by a part of the barrier layer, is disposed between the heating elements, extends in a direction perpendicular to the arrangement direction of the heating elements, and both sides in a direction perpendicular to the arrangement direction of the heating elements. A partition wall from which liquid can flow into the heating element side,
It is formed by a part of the barrier layer, and N (N is an integer greater than or equal to 2) number of the heating elements and (N-1) number of the partition walls are arranged outside these parallel to the partition walls. A pair of side walls;
A rear wall provided along a direction in which the heating elements are arranged, and formed by a part of the barrier layer,
When the distance between the partition wall and the rear wall is x, and the distance between the side wall and the rear wall is y,
0 ≦ y <x
And
The liquid discharge unit includes the N heating elements, the (N-1) partition walls, the pair of side walls, and the rear wall, and is disposed on the side opposite to the rear wall with respect to the heating elements. A liquid discharge head, characterized in that a common flow path is provided and liquid is supplied from the common flow path side and the opposite side to the heat generating element side of the liquid discharge unit. The liquid discharge head according to claim 1,
2 ≦ N ≦ 8
A liquid discharge head characterized by the above. The liquid discharge head according to claim 1,
The interval W1 between the partition walls and the partition wall and the side wall on the region of the heating element, and the interval W2 between the partition walls and the partition wall and the side wall at the common channel side end are:
W2 <W1
A liquid discharge head characterized by the above. The liquid discharge head according to claim 1,
The liquid discharge head according to claim 1, wherein the side of the side wall of the partition wall is closer to the side of the common channel than the side of the common channel. The liquid discharge head according to claim 1,
The common flow path includes a filter including a plurality of pillars formed by a part of the barrier layer,
The columns of the filter are arranged at a pitch different from the arrangement pitch of the heating elements,
The common channel side end of the side wall is located on the side away from the heat generating element with respect to the common channel side end of the partition wall,
The liquid discharge head, wherein the common flow path side end of the side wall is connected to the column of the filter. The liquid discharge head according to claim 1,
A plurality of the liquid discharge units are provided on one semiconductor substrate, and all the nozzles of the plurality of liquid discharge units are arranged at a constant pitch. The liquid discharge head according to claim 6,
A plurality of the liquid discharge units are arranged at an outer edge portion of one side of the semiconductor substrate. The liquid discharge head according to claim 6,
A plurality of the liquid discharge units are respectively disposed on outer edges of two opposing sides of the semiconductor substrate. The liquid discharge head according to claim 6,
In the semiconductor substrate, a long hole penetrating from the back side to the front side is formed,
A plurality of the liquid discharge units are arranged opposite to each other along the long hole. The liquid discharge head according to claim 1,
A plurality of the semiconductor substrates are arranged in a line along the arrangement direction of the heating elements, and a line head is formed by providing the common flow path of each of the semiconductor substrates along the arrangement direction in the semiconductor substrate. A liquid discharge head. The liquid discharge head according to claim 10, wherein
A plurality of the semiconductor substrates arranged in a line shape are arranged in a row,
A liquid ejection head, wherein liquids having different characteristics are supplied to the plurality of semiconductor substrates in one row and the plurality of semiconductor substrates in another row. A heating element provided on a semiconductor substrate and arranged in a plurality along one direction;
A nozzle layer in which nozzles located on the heating elements are formed;
A barrier layer provided between the semiconductor substrate and the nozzle layer;
The barrier layer is formed by a part of the barrier layer, is disposed between the heating elements, extends in a direction perpendicular to the arrangement direction of the heating elements, and both sides in a direction perpendicular to the arrangement direction of the heating elements. A partition wall from which liquid can flow into the heating element side,
It is formed by a part of the barrier layer, and N (N is an integer greater than or equal to 2) number of the heating elements and (N-1) number of the partition walls are arranged outside these parallel to the partition walls. A pair of side walls;
A rear wall provided along a direction in which the heating elements are arranged, and formed by a part of the barrier layer,
When the distance between the partition wall and the rear wall is x, and the distance between the side wall and the rear wall is y,
0 ≦ y <x
And
The liquid discharge unit includes the N heating elements, the (N-1) partition walls, the pair of side walls, and the rear wall, and is disposed on the side opposite to the rear wall with respect to the heating elements. A liquid discharge apparatus comprising: a liquid discharge head provided with a common flow path and formed so that liquid is supplied from the common flow path side and the opposite side to the heat generating element side of the liquid discharge unit.