JPH0760958A - Line type ink jet head - Google Patents

Abstract

PURPOSE:To obtain a line type ink jet head wherein crosstalk is not generated between an adjacent pressure chamber and a passage by a method wherein a plurality of pressure chambers are arranged in a plurality of lines and in a zigzag manner in parallel with a line of nozzle parts. CONSTITUTION:A plurality of pressure chamber 102 or the like and 201 or the like are arranged in two lines in parallel with a line of nozzle parts 501 or the like. The pressure chambers 102 or the like arranged in a first line from a first line pressure chamber group. The pressure chambers positioned in a second line form a second line pressure chamber group. The pressure chamber 102 or the like belonging to the first line pressure chamber group and the pressure chambers 201 or the like belonging to the second pressure chamber group are alternately arranged in a zigzag manner. A width of the pressure chamber belonging to the second line pressure chamber group is formed smaller by being compared with that of the pressure chamber belonging to the first line pressure chamber group.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure chamber for applying pressure to ink by a piezoelectric element, a plurality of nozzles for ejecting ink pressurized by the pressure chamber, and ink for ejecting the ink from the pressure chamber. The present invention relates to a line-type inkjet head having a plurality of flow paths leading to a nozzle section and having a plurality of nozzle sections arranged in a straight line.

[0002]

2. Description of the Related Art Among conventional Kaiser type ink jet heads, a serial head is mainly used and the number of dots is four.
The 8-dot type is the mainstream.

As shown in FIG. 6, the serial head having circularly arranged pressure chambers has a pressure chamber 2 for applying pressure to ink by a piezoelectric element (not shown), and an ink to which pressure is applied by the pressure chamber 2. A plurality of sets of ink ejecting means including a flow path 3 that guides the ink to the nozzle section 5 and a nozzle section 5 that ejects the ink guided by the flow path 3 are provided, and the plurality of nozzle sections 5 are arranged linearly. The pressure chambers 2 are arranged in a circle. A common ink passage 10 is formed outside the pressure chambers 1.

A serial head having pressure chambers arranged in series and opposite to each other, as shown in FIG.
A plurality of sets of ink ejecting means including a pressure chamber 2 that applies pressure to the ink by a piezoelectric element (not shown) and a nozzle unit 5 that ejects the ink to which pressure is applied by the pressure chamber 2 are provided. The pressure chambers 2 are arranged in series and opposite to each other, and the nozzle portion 5 is arranged linearly. A common ink passage 10 is formed outside the pressure chambers 2.

Here, in the serial head in which the pressure chambers are arranged in a circle, the head size is 30 to 35 mm square.

[0006]

However, the above-mentioned conventional serial head has a small dot density of 4 dots / m.
When a head having a printing width of m and 2 inches is to be constructed (the number of dots is 224 dots), the maximum distance from the pressure chamber to the nozzle is 35.6 mm in the serial head arranged in the above circular shape. Is 85-90 mm
It becomes the size of the corner.

Further, as shown in FIG. 5, in the type in which the pressure chambers 2 are vertically arranged in a horizontal row and the ink is ejected from the nozzle portion 5 arranged at the substantially center, the length in the longitudinal direction is 1
20 mm, the length in the short side direction is about 33 mm, the head size is larger than the print width, and the length of the flow path is long, so that the flow path resistance is high for ejecting ink, the piezoelectric element is high. However, the driving voltage of the device becomes high, which is not practical.

Therefore, as a solution to this problem, the present applicant, as shown in FIG. 4, has a line type in which a plurality of pressure chambers are arranged in parallel in a plurality of rows in a staggered manner with respect to the rows of nozzle portions. Inventing an inkjet head. That is, as shown in FIG. 4, the common ink passage 10 and the nozzle portion 5
The pressure chambers provided between the first pressure chambers 102, 104, 106, ... Pressure chambers 201, 203, 205 belonging to the pressure chamber group
.. are arranged in two rows in a zigzag manner, and further, the width of the flow passage is increased in proportion to the length of the flow passages 301, 302, 303 ... Is uniform. That is, in the relationship between the adjacent flow paths, the width of the flow paths 302, 304 connected to the pressure chambers of the first row pressure chamber group is equal to the width of the flow path 30 connected to the pressure chambers of the second row pressure chamber group.
1, 303, etc. are formed wider than the width, and even a flow path connected to pressure chambers belonging to the same pressure chamber group is provided in a pressure chamber outside the flow path connected to the central pressure chamber. The connected flow path has a larger width. Here, the pressure chambers 102 and the like belonging to the first row pressure chamber group and the pressure chambers 201 and the like belonging to the second row pressure chamber group are formed to have the same width.

However, in the line type ink jet head shown in FIG. 4, the pressure chambers 201 and the like belonging to the second row pressure chamber group and the flow passages 302 and 304 connecting the pressure chambers 102 and the like belonging to the first row pressure chamber group are formed. When the voltage is applied to the piezoelectric element such as the pressure chamber 201 belonging to the second row pressure chamber group, the partition walls are thin, and the passage 302 and the like such as the pressure chamber 102 belonging to the adjacent first row pressure chamber group are vibrated. There was a risk that it would be transmitted and crosstalk would occur. For example, when pressure is applied to the pressure chamber 204, the vibration is transmitted to the flow channel 308 via the partition between the pressure chamber 204 and the flow channel 308, and the ink in the flow channel 308 is ejected. This problem is particularly remarkable when the substrate is made of resin. To solve this problem,
There is a method of thickening the partition wall between the pressure chambers of the second row pressure chamber group and the flow passages connecting from the pressure chambers of the first row pressure chamber group adjacent thereto, but this method has a problem that the line type inkjet head becomes large. was there.

Therefore, the present invention has been made to solve the above-mentioned problems, and when a plurality of pressure chambers are arranged in a plurality of rows and in a staggered pattern in parallel with the rows of the nozzle portions, It is an object of the present invention to provide a line type inkjet head in which crosstalk does not occur between adjacent pressure chambers and channels.

[0011]

In a line type ink jet head according to the present invention, firstly, a plurality of pressure chambers for applying pressure to ink by a piezoelectric element and an ink to which pressure is applied by the pressure chambers are provided. A plurality of nozzles to eject,
In a line-type inkjet head having a plurality of flow paths for guiding ink from the pressure chamber to the nozzle portion, and the nozzle portion being linearly arranged, at least one side of the row of the nozzle portions is provided with the plurality of the plurality of nozzles. The pressure chambers are arranged in a plurality of rows in a zigzag manner in parallel to the row of the nozzle portions, and compared with the pressure chambers in the row farthest from the row of the nozzle portions
It is characterized in that the width of the pressure chambers in the other rows is reduced.

Secondly, in the above-mentioned first structure, in the flow passage connecting the nozzles from the pressure chambers in the rows other than the farthest position, the width of the flow passage is the same as that of all the pressure chambers. It is characterized in that it is made larger than the case where it is set.

Thirdly, in the first structure, the driving voltage of the piezoelectric elements in the pressure chambers in the columns other than the farthest position is set to be larger than that in the case where all the pressure chambers have the same width. It is characterized by having done.

Fourthly, in the above-mentioned first structure, the length of the pressure chambers in the rows other than the farthest position in the flow path direction is made larger than that of the pressure chambers in the farthest position. It is a feature.

[0015]

In the line type ink jet head according to the present invention, pressure is applied to the ink in the pressure chamber by applying a voltage to the piezoelectric element, and the ink is ejected from the nozzle portion through the flow path. In the present invention, the plurality of pressure chambers are arranged in a plurality of rows and in a staggered manner in parallel to the row of the nozzle sections on at least one side of the row of the nozzle sections, and the farthest from the row of the nozzle sections. The width of the pressure chambers in the other rows is smaller than that of the pressure chambers in the other row, so the pressure chambers in the other rows are separated from the flow passages connected by the pressure chambers in the farthest row. Since the distance can be increased, the vibration of the diaphragm above the pressure chamber is not transmitted to the adjacent flow path, and thus crosstalk does not occur.

Further, in the second structure, in the flow path connecting from the pressure chambers in the rows other than the farthest position to the nozzle portion,
Since the width of the flow path is made larger than that in the case where all the pressure chambers have the same width, the flow path resistance becomes small, and the discharge force of the discharge force by reducing the width of the pressure chamber in the first configuration is reduced. The decrease can be suppressed.

Also in the third configuration, the driving voltage of the piezoelectric elements in the pressure chambers in the rows other than the farthest position is made larger than that in the case where the widths of all the pressure chambers are the same, so that the ink in the pressure chambers Since the pressure applied to the pressure chamber is increased, it is possible to prevent the discharge force from being reduced by reducing the width of the pressure chamber in the first configuration.

Further, also in the fourth configuration, the lengths of the pressure chambers in the rows other than the furthest position in the flow path direction are made larger than those in the rows in the farthest position. It is possible to equalize the volumes of the pressure chambers by reducing the width, and it is possible to suppress the decrease in the ejection force due to the reduction of the width of the pressure chambers in the first configuration.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In the line type ink jet head according to this embodiment, an ink path pattern as shown in FIG. 1 is formed on a substrate, and a vibration plate (not shown) is fixed on the ink path forming side of the substrate, and the vibration plate is formed on the vibration plate. A piezoelectric element (not shown) is formed on.

On the substrate, pressure chambers 102, 104, 106, 108, ... 20 for applying pressure to the ink by the piezoelectric elements according to the ink path pattern as shown in FIG.
1, 203, 205, 207 ..., Nozzle sections 501, 502, 503 ... for ejecting ink, and a flow path 4 for guiding ink from the supply ink path 10 to the pressure chamber 102 and the like.
, And flow paths 301, 302, 303, ... For guiding the ink to which pressure is applied by the pressure chamber 102 and the like to the nozzle portion 501 and the like.

Here, in this embodiment, the plurality of pressure chambers 102 and 201 and the like are arranged in two rows parallel to the row of the nozzle portion 501 and the like, and are located in the first row. The pressure chambers 102 and the like form a first row pressure chamber group, and the pressure chambers 201 and the like located in the second row form a second row pressure chamber group. Further, in the present embodiment, the pressure chambers 102 and the like belonging to the first row pressure chamber group and the pressure chambers 2 belonging to the second row pressure chamber group.
01 and the like are alternately arranged in a staggered pattern.

Here, in the present invention, the width of the pressure chambers belonging to the second row pressure chamber group is formed smaller than that of the pressure chambers belonging to the first row pressure chamber group. For example, the pressure chamber 20
The width W1 of the pressure chamber 108 is smaller than the width W2 of the pressure chamber 108, so that the thickness of the partition between the pressure chamber of the second row pressure chamber group and the flow passage adjacent to the pressure chamber is smaller than the width of the pressure chamber. In the case of the same, it is expanded from 0.1 mm to 0.15 mm, and the strength of the partition wall is about three times as strong. That is, for example, the partition between the pressure chamber 207 and the flow path 308 is enlarged compared to the case where the width of the pressure chamber is the same. Therefore, the pressure chamber 20
When a voltage is applied to the piezoelectric element of No. 7, the adjacent flow path 3
It is possible to prevent vibration from being transmitted to 08 and prevent crosstalk from occurring.

Next, in the flow passages between the pressure chambers 102 and 201 and the nozzle portion 501 and the like, the flow passages 30 that are connected to the pressure chambers of the first row pressure chamber group due to the relationship of the adjacent flow passages.
The width of 2, 304, etc. is formed wider than the width of the flow paths 301, 303, etc. connected to the pressure chambers of the second row pressure chamber group. For example, in the flow channels 307 and 308, the flow channel 308 connected to the pressure chamber 108 belonging to the first row pressure chamber group is connected to the pressure chamber 207 belonging to the second row pressure chamber group.
It has a width greater than 7. This is because the flow path connecting to the pressure chambers of the first row pressure chamber group is longer than that of the pressure chambers of the second row pressure chamber group, and thus the inertance differs when the widths are the same, and the injection timing is shifted. .

However, when the pressure chambers of the first row pressure chamber group and the second row pressure chamber group have the same width, that is, as compared with the case shown in FIG. The width of the road is large. For example, the flow path 307 connected to the pressure chamber 207 has a width slightly larger than that in FIG. This is to prevent the discharge force from decreasing due to the width of the pressure chamber being reduced.

That is, the width W of the pressure chamber of the second row pressure chamber group
1 from the width W20.8 mm of the pressure chamber of the first pressure chamber group to 0.
Reduced the width of the piezoelectric element from 7 mm to 0.6 mm
When narrowed to mm, the pressure applied to the pressure chamber is 0.6 / 0.7 = 0.87. At this time, the inertance of the flow path 3 is set to this ratio (0.8
It is necessary to reduce in 7).

In this embodiment, FIG. 2 showing the case of FIG.
As shown in FIG. 2B, the width of the flow path between the pressure chamber and the nozzle portion was changed as compared with FIG. For example, in lot number 23, the width R of the flow path 307 is expanded from 0.246 mm to 0.342 mm, and its inertance is decreased from 1.21E + 08 to 1.03E + 08. As described above, the inertance of the flow path between the pressure chamber and the nozzle portion is reduced to prevent the ejection force and the ejection speed from decreasing when the width of the pressure chamber is reduced. It should be noted that R in FIG. 2 indicates the width of each flow passage at a position closest to the pressure chamber, such as the flow passage 301 connected to the pressure chamber.
X and Y indicate the coordinates of the points where the vertical and diagonal center lines intersect in the flow path and pressure chamber of each lot number.

Further, in the flow path between the pressure chambers 102 and 201 and the nozzle portion 501 and the like, the flow path connecting to each row of the first row pressure chamber group and the second row pressure chamber group is located at the center. The width of the flow passage is narrowed toward the flow passage, and the width is increased toward the end. That is, for example, in the flow passages 305 and 307, even if the flow passages are connected to the pressure chambers of the same second row pressure chamber group, the width of the flow passage 307 located in the center is smaller. This is because the nozzle portion 501 and the like are located in the center, so that the length of the flow path becomes longer toward the end, and the width of the flow path is widened to make the inertance uniform. The flow channel 30a located on the rightmost side in the drawing
Since the pressure chamber 20a is formed to be half the size of the other pressure chambers, it is formed narrow.

Further, the common ink passage 10 and each pressure chamber 102
.., 201 ..., etc., also in the flow path 401 connecting the pressure chambers of the first row pressure chamber group, the width of the flow paths 402, 404 connecting to the pressure chambers of the first row pressure chamber group connects to the pressure chambers of the second row pressure chamber group 40
It is formed narrower than the width of 1, 403 and the like. This is also to make the inertance up to the pressure chamber uniform. A head having a print width of 4 dots / mm and 2 inches having upper and lower ink path patterns based on the above configuration is shown in FIG.
When the above is configured (the number of dots is 224 dots), the length in the nozzle direction is 80 mm and the length of the other side is about 41 m.
Therefore, the head size can be made smaller than that of the conventional example of FIG. The nozzles 501 and the like are arranged in two rows in the approximate center of the head.

In the above embodiment, the plurality of pressure chambers 102, 201, etc. are arranged in two rows and in a staggered pattern in parallel with the rows of the nozzle section 501, etc. It may be configured. Further, in the above-mentioned embodiment, the problem of the decrease in discharge force due to the reduction of the width of the pressure chamber was solved by increasing the width of the flow path, but the invention is not limited to this, and the second row pressure with a reduced width is used. Increase the drive voltage of the piezoelectric element of the pressure chamber of the chamber group, or increase the length of the pressure chamber of the second row pressure chamber group of the width reduced in the flow path direction, and at the same time increase the length of the piezoelectric element. The deflection amount of the piezoelectric element may be increased to prevent the pressure applied to the ink from decreasing.

[0031]

As described above, according to the present invention, the plurality of pressure chambers are arranged in a plurality of rows and in a staggered pattern on at least one side of the nozzle section row in parallel with the nozzle section row. Since the width of the pressure chambers in the other rows is smaller than that of the pressure chambers in the row farthest from the row of the nozzle portions, the pressure chambers in the other rows are farthest from the pressure chambers in the other row. The distance between the pressure chambers in the row and the flow passage connected to it can be increased, the vibration of the diaphragm above the pressure chambers does not propagate to the adjacent flow passages, and crosstalk does not occur. You can provide a good printer.

Further, in the flow path connecting the pressure chambers in the rows other than the furthest position to the nozzle portion, when the width of the flow path is made larger than that in the case where all the pressure chambers have the same width, The flow path resistance is reduced, and it is possible to prevent the discharge force from being reduced by reducing the width of the pressure chamber.

Also, the width of the pressure chambers should be reduced even when the drive voltage of the piezoelectric elements in the pressure chambers in the rows other than the furthest position is made larger than when the widths of all the pressure chambers are made the same. It is possible to suppress the decrease in the ejection force due to.

Further, when the length in the flow path direction of the pressure chambers in the rows other than the farthest position is made larger than that in the pressure chambers in the farthest row, the volume of the pressure chambers is reduced by reducing the width. Can be made equal to each other, and a decrease in ejection force due to a reduction in width of the pressure chamber can be suppressed.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a line type inkjet head according to the present invention.

FIG. 2 is an explanatory view showing an example of changing the width of the pressure chamber of the line type inkjet head according to the present invention.

FIG. 3 is an explanatory diagram showing a schematic configuration of a head having a print width of 2 inches to which the line type inkjet head according to the present invention is applied.

FIG. 4 is an explanatory diagram showing a schematic configuration of a line-type inkjet head that the present applicant has already devised.

FIG. 5 is an explanatory diagram showing a schematic configuration of a head having a print width of 2 inches when the pressure chambers are arranged in a horizontal row.

FIG. 6 is a schematic configuration diagram showing a general serial head in which pressure chambers are arranged in a circle.

FIG. 7 is a schematic configuration diagram showing a general serial head in which pressure chambers are arranged in series and face each other.

[Explanation of symbols]

10 common ink paths 102, 104, 106, 108, 201, 203, 2
05, 207 Pressure chambers 301, 302, 303, 304, 305, 306, 3
07, 308 Channels 501, 502, 503, 504, 505, 506, 5
07,508 Nozzle part

Claims (4)

[Claims] 1. A plurality of pressure chambers for applying pressure to ink by a piezoelectric element, a plurality of nozzles for ejecting ink pressurized by the pressure chambers, and an ink for guiding the ink from the pressure chambers to the nozzles. In a line-type inkjet head having a plurality of flow paths and linearly arranging the nozzle portions, the plurality of pressure chambers are provided on at least one side of the nozzle portion row with respect to the nozzle portion row. A line characterized by arranging in parallel in a plurality of rows and in a staggered pattern, and making the width of the pressure chambers in other rows smaller than the pressure chambers in the row farthest from the nozzle section row. Type inkjet head. 2. The flow path connecting the nozzles from the pressure chambers in a row other than the furthest position has a width larger than that in the case where all the pressure chambers have the same width. The line-type inkjet head according to claim 1. 3. The line according to claim 1, wherein the drive voltage of the piezoelectric elements of the pressure chambers in the columns other than the furthest position is made larger than that in the case where all the pressure chambers have the same width. Type inkjet head. 4. The line-type inkjet head according to claim 1, wherein the length of the pressure chambers in the rows other than the furthest position in the flow path direction is larger than that of the pressure chambers in the farthest row. .