JP2004284277A - Ink jet recording head, ink jet recording device and method for supplying ink to ink jet recording head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To diminish the dispersion of ink discharge characteristics; miniaturize an ink jet recording device; cut a manufacturing cost to a low level; and realize successful air bubble discharge performance. <P>SOLUTION: The ink jet recording head is formed in the way that an ink pool 20 for supplying ink communicates with a plurality of pressure chambers 14 at a part other than a columnar part 28 where a nozzle communication chamber 16 is formed and is almost of the same width as the length of a train of nozzle rows where a plurality of nozzles 12 are arranged. The ink pool 20 is of such a structure that it is shared by a plurality of the pressure chambers 14 and the ink contained in the ink pool 20 is supplied to each of the pressure chambers 14, passing through an ink supply path 18 from an opening part 22. Thus, it is possible to stabilize the ink discharge characteristics without increasing the depth of the ink pool 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an ink jet recording head that records an image by discharging ink, an ink jet recording apparatus using the ink jet recording head, and a method of filling the ink into the ink jet recording head.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, as an ink jet recording head having a large number of nozzles for ejecting ink droplets arranged in a matrix, for example, the one shown in FIG. 13 has been disclosed.
[0003]
The ink jet recording head includes a plurality of nozzles 102 from which ink droplets are ejected, a plurality of pressure chambers 104 communicating with the individual nozzles 102 and pressurizing ink, and ink from an ink cartridge (not shown) through an opening 112. The main flow 110 includes an ink pool main flow 110 that is introduced through the ink pool main flow, and an ink pool tributary flow 108 that extends in a comb-like shape from the ink pool main flow 110. The ink pool branch 108 communicates with each pressure chamber 104 via a plurality of supply ports 106. Further, as shown in FIG. 14, a piezoelectric element 116 having an individual electrode 114 is attached to the bottom surface of the pressure chamber 104.
[0004]
In such an ink jet recording head, ink from an ink cartridge (not shown) is introduced into the main pool 110 of the ink through the opening 112, and the ink is further divided into the tributary of the ink pool 108. The ink that has flowed into the ink pool branch 108 is supplied from a plurality of supply ports 106 to the individual pressure chambers 104 communicating therewith. In the pressure chamber 104, the piezoelectric element 116 is driven by applying a voltage to the individual electrode 114, and ink droplets are ejected from the nozzle 102 by pressurizing the ink (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
JP 2001-334661 A
[Problems to be solved by the invention]
However, in the above-described ink jet recording head, when the length of the nozzle array arranged along one ink pool branch 108 is increased, the ink pool branch 108 has a narrow width, so that the fluid resistance of the ink is large, and the ink ejection characteristics are increased. Causes variations. In particular, the characteristics differ between the tributary tip and the tributary root due to the difference in fluid resistance. In order to reduce the fluid resistance of the ink, it is necessary to increase the depth of the ink pool, and there is a problem that the outer shape of the head becomes large and the cost increases.
[0007]
As shown in FIG. 13, each ink pool branch 108 has a branch end 109 at a downstream portion in the ink flow direction. For this reason, the ink flow tends to stagnate in the vicinity of each of the tributary ends 109, and air bubbles remain in the stagnation areas. Discharge is a problem.
[0008]
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to stabilize ink ejection characteristics and improve bubble discharge performance.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, an ink jet recording head according to the first aspect of the present invention has a nozzle plate in which nozzles for discharging ink droplets are formed in a row, and discharges stored ink from each of the nozzles. In an ink jet recording head including a pressure chamber to be made, and an ink pool for supplying ink to the pressure chamber, the pressure chamber storing the same color ink is formed in a different layer from the pressure chamber, and the same color ink is formed. Ink is supplied from an ink pool having substantially the same width as the matrix length of a plurality of nozzle rows to be ejected.
[0010]
According to the inkjet recording head of the first aspect, the ink is supplied from the common ink pool to the pressure chamber storing the same color ink. The width of the ink pool is substantially the same as the length of the rows and columns of the plurality of nozzle rows, and is a large space. Note that “matrix length” refers to the length of a row orthogonal to a column. This makes it possible to reduce the fluid resistance of the ink in the ink pool. For this reason, the ink discharge characteristics can be stabilized without increasing the ink pool and increasing the head size. At the same time, it is possible to reduce the size and cost of the head.
[0011]
In the inkjet recording head according to the second aspect of the present invention, in the configuration according to the first aspect, the length of the ink pool is longer than the length of the nozzle row, and ink is applied to both ends of the ink pool. It is characterized in that an ink supply port to be supplied is formed.
[0012]
According to the inkjet recording head of the present invention, the length of the ink pool is longer than the length of the nozzle row, the ink supply ports are arranged at both ends of the ink pool, and ink is introduced from both ink supply ports. You. For this reason, unlike the conventional ink pool, a flow end wall is not formed, and it is difficult to form a stagnation portion of the ink, and it is possible to improve the bubble discharging property.
[0013]
According to a third aspect of the present invention, in the ink jet recording head according to the second aspect, at least one of the ink supply ports is provided with an adjustment valve for adjusting an inflow amount of the ink. I have.
[0014]
According to the inkjet recording head of the third aspect, when the ink in the ink cartridge is supplied into the ink pool from the two ink supply ports, the inflow amount of at least one of the ink supply ports is adjusted. be able to. For this reason, it is possible to shift the position where the ink introduced from the two ink supply ports hits in the ink pool.
[0015]
That is, when the ink introduced from the two ink supply ports always hits near the center of the ink pool, the flow of ink in that portion becomes unstable, and there is a concern that bubbles may remain. As described above, by shifting the position where the ink strikes in the ink pool, the ink stagnation portion can be moved. For this reason, air bubbles are less likely to remain in the ink pool, and the air bubble discharging property can be improved. Note that “adjusting the inflow amount” means stopping the inflow.
[0016]
According to a fourth aspect of the present invention, there is provided an inkjet recording apparatus using the inkjet recording head according to the first to third aspects.
[0017]
According to the inkjet recording apparatus of the fourth aspect, by using the inkjet recording head of the first aspect, it is possible to realize an apparatus having a small variation in ink ejection characteristics, and to prevent the occurrence of image unevenness and the like. it can. Further, the cost of the entire apparatus can be reduced. Further, by using the ink jet recording head according to claim 2 or 3, it is possible to improve the bubble discharging property and obtain a high quality image free from ejection failure.
[0018]
According to a fifth aspect of the present invention, in the method for supplying ink to the ink jet recording head according to the third aspect, a step of opening the adjustment valve and sucking ink from the nozzle for a predetermined time, Closing the regulating valve and re-suctioning the ink from the nozzles.
[0019]
According to the method of supplying ink to an ink jet recording head according to claim 5, the ink stagnation point is moved by changing the amount of ink flowing from the two ink supply ports during the first and second ink suctions. In addition, the bubble discharging property can be improved. As a result, a high-quality image with few ejection failures can be obtained.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of an inkjet recording head according to the present invention will be described with reference to FIGS.
[0021]
As shown in FIGS. 1 and 4, the ink jet recording head 10 includes a nozzle 12 for ejecting a plurality of ink droplets opened in a matrix, and a plurality of pressure chambers 14 for pressurizing the stored ink. Further, a nozzle communication chamber 16 that communicates the nozzle 12 with the pressure chamber 14, an ink supply path 18 that supplies ink to the pressure chamber 14, and an ink pool 20 that guides ink to an opening 22 of the ink supply path 18 are provided. Have. The ink pool 20 is provided in a lower layer different from the upper pressure chambers 14.
[0022]
The inkjet recording head 10 includes a nozzle plate 24 in which the nozzles 12 are formed, an ink pool plate 26 in which the nozzle communication chamber 16 and the ink pool 20 are formed, and a through plate in which the nozzle communication chamber 16 and the opening 22 are formed. 30, an ink supply path plate 32 in which the ink supply path 18 is formed, and a pressure chamber plate 34 in which the pressure chamber 14 is formed, and then the surface of the nozzle plate 24 is coated with a water-repellent coating film. In addition, it is made by opening a plurality of nozzles 12 with an excimer laser. After the joining, the surface opposite to the nozzle 12 is in a state where the nozzle communication chamber 16, the pressure chamber 14, the ink supply path 18, and the opening 22 are open.
[0023]
Further, as shown in FIG. 4, a vibrating plate 36 closing the upper surface of the pressure chamber 14, a piezoelectric element 38 bonded at a position facing the pressure chamber 14, and a piezoelectric element 38 And an electric board 42 bonded thereon via a ball solder 40.
[0024]
The material of the nozzle plate 24 is polyimide, and the material of the ink pool plate 26, the through plate 30, and the ink supply path plate 32 is SUS.
[0025]
As shown in FIGS. 2 and 3, the plurality of nozzles 12 are arranged in the longitudinal direction so as to form a plurality of nozzle rows (vertical rows in the drawings) that eject the same color ink. Four ink pools 20 having substantially the same width as the matrix length of the plurality of nozzle rows are provided. The ink pool 20 is provided with a plurality of cylindrical portions 28 in which the nozzle communication chambers 16 are formed, but has a large space in which the other portions communicate. The ink supply path 18 and the pressure chamber 14 communicate with the ink pool 20 via the opening 22, and the pressure chamber 14 has a structure in which one ink pool 20 is shared.
[0026]
As shown in FIGS. 6 and 7, four YMCK ink cartridges 52 for refilling ink are mounted in the carriage 50 so as to be replaceable. As shown in FIG. 3, an ink supply port 44 is provided at one end in the longitudinal direction of the ink pool 20, and the ink supply port 44 is connected to an ink cartridge 52 via an ink introduction pipe 54. Have been.
[0027]
As shown in FIGS. 3 and 5, an inner wall 46 is formed at an end in the flow direction of the ink supplied from the ink supply port 44 into the ink pool 20 in a direction inclined with respect to the flow direction. A plurality of openings 22 communicating with the ink supply path 18 are arranged near the inner wall 46.
[0028]
Next, the operation of the ink jet recording head 10 will be described.
[0029]
The ink in the ink cartridge 52 is supplied to the ink pool 20 from the ink supply port 44 through the ink introduction pipe 54. The ink supplied into the ink pool 20 flows toward the opposite side of the ink supply port 44 in the longitudinal direction. A plurality of ink supply paths 18 communicate with the ink pool 20 through the opening 22, and ink is supplied to each pressure chamber 14 through the opening 22 and the ink supply path 18. Further, the ink in the ink pool 20 collides with the inner wall 46 on the downstream side in the longitudinal direction, and flows along the inclination direction of the inner wall 46.
[0030]
On the other hand, in the pressure chamber 14, when a voltage is applied from a power supply (not shown) to the piezoelectric element 38, the diaphragm 36 is deformed in the direction of the pressure chamber 14, and the ink in the pressure chamber 14 is pressurized. Accordingly, ink droplets are ejected from the nozzles 12 of the nozzle communication chamber 16.
[0031]
In such an ink jet recording head, the ink pool 20 that supplies the same color ink to each pressure chamber 14 (the upper and lower ink pools on the left side in FIG. 3 have the same color) has a wide width substantially the same as the matrix length of the plurality of nozzle rows. Since it is formed as a space, the downstream portion D of the ink pool in the ink flow direction is not a flow end portion of a tributary structure as in the related art, but has a wide inner wall 46. Therefore, the fluid resistance of the ink in the ink pool 20 can be reduced, and the ink ejection characteristics can be stabilized. Further, in such a configuration, it is not necessary to increase the head size by making the ink pool deep, so that the size and cost of the inkjet recording head 10 can be reduced.
[0032]
Next, a second embodiment according to the present invention will be described with reference to FIGS.
[0033]
The members described in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted.
[0034]
As shown in FIG. 8, the inkjet recording head 60 includes an ink pool 62 having a central portion connected in the longitudinal direction, and the length of the ink pool 62 is longer than the length of the nozzle row in which the plurality of nozzles 12 are arranged. It is set long. At both ends in the longitudinal direction of the ink pool 62, ink supply ports 44a and 44b are formed. With such a structure, a structure without the ink pool downstream part D as shown in FIG. 5 of the first embodiment can be obtained.
[0035]
As shown in FIG. 9, an ink introduction pipe 54 connected to one of the ink supply ports 44a has an adjustment valve 66 for adjusting the amount of ink flowing from the ink cartridge 52, and controls opening and closing of the adjustment valve 66. Control means 68 is provided. The regulating valve 66 is made of a piezoelectric element, contracts when a voltage is applied, changes the aperture ratio, and functions as a valve.
[0036]
As shown in FIG. 9, a cap 72 for sucking ink from the nozzles 12 is provided at a position facing the inkjet recording head 60. The cap 72 seals the nozzle 12 from the outside. Further, the cap 72 includes a pump 74 for suctioning ink from the nozzles 12 by applying a negative pressure to the inside of the cap 72, and a pipe 76 for discharging the sucked ink.
[0037]
Next, the ink suction operation of the ink jet recording head 60 will be described with reference to the flowchart shown in FIG.
[0038]
The ink suction is set so as to be performed periodically when the power of the ink jet recording apparatus is turned on or every time a certain use time elapses.
[0039]
When ink suction is started, first, at step 80, the adjustment valve 66 is opened to make a state where ink can flow from the ink supply ports 44a and 44b. Next, in step 82, the cap 72 is raised as shown in FIG. 10, and is pressed against the nozzle plate 24 provided with the nozzles 12. Then, in step 84, the pump 74 is driven to perform the first ink suction from the nozzle 12. By driving the pump 74, the pressure inside the cap 72 becomes negative, and ink is discharged from the nozzles 12 of the ink jet recording head 60 together with bubbles through the pipe 76.
[0040]
In step 86, it is determined whether a predetermined time has elapsed after the suction. If the result is affirmative, the pump 74 is stopped in step 88 to terminate the first ink suction, and the adjustment valve 66 is closed in step 90. Thus, the setting is such that the ink does not flow from the ink supply port 44a and the ink flows only from the ink supply port 44b. In step 92, the pump 74 is driven to perform the second ink suction from the nozzle 12. Due to the ink suction, the residual bubbles in the ink pool 62 move, and the residual bubbles are discharged from the nozzle 12 together with the ink. Then, it is determined in step 94 whether a predetermined time has elapsed. If the result is affirmative, the pump 74 is stopped in step 96 to terminate the second ink suction.
[0041]
In the above-mentioned ink jet recording head, it is also possible to consider a structure in which an ink pool into which ink enters from the ink supply ports 44a and 44b is simply connected at the center without providing the adjustment valve 66 and the control means 68. However, in such a structure, if ink is sucked from the nozzle 12 with the ink supply ports 44a and 44b opened, the ink flowing from the ink supply ports 44a and 44b collides near the center of the ink pool 62, Air bubbles are likely to remain. In addition, since the collision portion is always at the same location, the remaining air bubbles are difficult to remove by ink suction.
[0042]
In the ink jet recording head 60 of the present embodiment, as described above, after the first ink suction is performed by opening both the ink supply ports 44a and 44b, the adjustment valve 66 of one of the ink supply ports 44a is closed and the ink supply port 44a is closed again. Since the ink suction is performed, a portion of the ink pool 62 where the flow of the ink collides can be moved. Accordingly, the residual bubbles can be more reliably sucked and discharged from the nozzles 12, and the bubble discharge property in the ink pool 62 can be improved.
[0043]
In the present embodiment, the adjustment valve 66 is provided in one of the ink supply ports 44a, but an adjustment valve may be provided in both of the ink supply ports 44a and 44b. Further, the control means 68 controls the opening and closing of the adjustment valve 66, but is not limited thereto, and controls the degree of opening and closing of the adjustment valve to adjust the inflow amount of ink supplied to the ink pool. There may be. Further, in this embodiment, the ink suction is performed twice. However, the present invention is not limited to this. The ink suction may be performed a plurality of times, and the opening and closing of the adjustment valve may be controlled each time.
[0044]
Next, an embodiment of an ink jet recording apparatus using the ink jet recording head of the present invention having the above configuration will be described with reference to FIG.
[0045]
An inkjet recording apparatus 200 shown in FIG. 12 includes a transport roller 206 that transports a recording medium P in the S direction, an inkjet recording head 202 of the present invention that ejects ink droplets onto the recording medium P to record an image, A carriage 203 for accommodating the recording head 202, a transport unit 204 for scanning the inkjet recording head 202 in an M direction perpendicular to the transport direction of the recording medium P, and a cap 72 for sucking ink from nozzles of the inkjet recording head 202 are provided. ing. As the inkjet recording head 202, any of the inkjet recording head 10 according to the first embodiment of the present invention and the inkjet recording head 60 according to the second embodiment may be used. FIG. 12 illustrates a state where the ink cartridge is mounted on the inkjet recording head.
[0046]
In such an inkjet recording apparatus 200, the recording medium P is transported in the S direction by the transport roller 206, and an image of the area BE on the recording medium P is written by the inkjet recording head 202 in one scan in the M direction. Then, the recording medium P is transported to a predetermined position in the S direction, and when the ink jet recording head 202 returns to the M direction, an image of the next area PE is written. Such operations are sequentially performed, and an image is formed on the recording medium P.
[0047]
In the inkjet recording apparatus 200, variations in the ink ejection characteristics of the inkjet recording head 202 can be reduced, and good air bubble discharge properties can be obtained. For this reason, it is possible to obtain a high-quality image without image quality defects.
[0048]
Further, the ink jet recording in this specification is not limited to the recording of characters and images on recording paper. That is, the recording medium is not limited to paper, and the liquid to be ejected is not limited to ink. For example, discharging ink on polymer film or glass to create a display color filter, or discharging solder in a welded state on a substrate to form bumps for component mounting, etc. The present invention can be applied to all droplet ejecting apparatuses used.
[0049]
【The invention's effect】
As described above, according to the ink jet recording head, the ink jet recording apparatus, and the method of supplying ink to the ink jet recording head according to the present invention, it is possible to stabilize the ink ejection characteristics without increasing the head size. Size and cost can be reduced. In addition, it is possible to improve the bubble discharging property in the head, and it is possible to solve problems such as defective ink ejection caused by residual bubbles.
[Brief description of the drawings]
FIG. 1 is a partial perspective view showing an ink jet recording head according to a first embodiment of the present invention.
FIG. 2 is a perspective plan view showing the ink jet recording head according to the first embodiment of the present invention.
FIG. 3 is a plan view illustrating an ink pool of the inkjet recording head according to the first embodiment of the present invention.
FIG. 4 is a cross-sectional view illustrating the inkjet recording head according to the first embodiment of the present invention.
FIG. 5 is an enlarged perspective plan view showing the inkjet recording head according to the first embodiment of the present invention.
FIG. 6 is a perspective view showing an ink jet recording head and an ink cartridge according to the first embodiment of the present invention.
FIG. 7 is a cross-sectional view illustrating the ink jet recording head and the ink cartridge according to the first embodiment of the present invention.
FIG. 8 is a plan view illustrating an ink pool of an inkjet recording head according to a second embodiment of the present invention.
FIG. 9 is a cross-sectional view illustrating an ink jet recording head, an ink cartridge, and a suction cap according to a second embodiment of the present invention.
FIG. 10 is a cross-sectional view showing a state in which a suction cap of an inkjet recording head according to a second embodiment of the present invention is used.
FIG. 11 is a flowchart illustrating an ink suction process of an inkjet recording head according to a second embodiment of the present invention.
FIG. 12 is a perspective view showing an ink jet recording apparatus using the ink jet recording head of the present invention.
FIG. 13 is a perspective plan view showing a conventional ink jet recording head.
FIG. 14 is a partial sectional view showing a conventional ink jet recording head.
[Explanation of symbols]
REFERENCE SIGNS LIST 10 ink jet recording head 12 nozzle 14 pressure chamber 18 ink supply path 20 ink pool 24 nozzle plate 44 ink supply port 44a ink supply port 44b ink supply port 52 ink cartridge 60 ink jet recording head 62 ink pool 66 adjustment valve 68 control means 72 cap 74 Pump 200 inkjet recording device

Claims (5)

An ink jet recording head comprising: a nozzle plate in which nozzles for discharging ink droplets are formed in a row; pressure chambers for discharging stored ink from each of the nozzles; and an ink pool for supplying ink to the pressure chambers. At
The pressure chamber for storing the same color ink is formed in a different layer from the pressure chamber, and ink is supplied from an ink pool having substantially the same width as a matrix length of a plurality of nozzle rows for discharging the same color ink. Inkjet recording head. The ink jet recording apparatus according to claim 1, wherein the length of the ink pool is longer than the length of the nozzle row, and ink supply ports for supplying ink are formed at both ends of the ink pool. head. 3. The ink jet recording head according to claim 2, wherein at least one of the ink supply ports is provided with an adjusting valve for adjusting an inflow amount of the ink. An inkjet recording apparatus using the inkjet recording head according to claim 1. A method for supplying ink to an inkjet recording head according to claim 3,
Opening the regulating valve and sucking ink from the nozzle for a predetermined time;
After a lapse of a predetermined time, one of the adjusting valves is closed, and the ink is sucked again from the nozzle;
A method for supplying ink to an ink jet recording head, comprising:

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