JP4338295B2 - Inkjet head, apparatus using the inkjet head, and filtering method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention uses an inkjet head for performing recording by ejecting ink, and the inkjet head.DressIn addition, the present invention relates to an ink filling device and an ink filling method for filling the ink jet head with ink, and further to a filtering device and a filtering method for removing foreign matters in the liquid, and is used in, for example, a printer, a copying machine, and a FAX.
[0002]
[Prior art]
In the on-demand type ink jet recording technology, a vibration plate is provided on a part of a wall of a liquid chamber filled with ink, and the vibration plate is displaced to change the volume in the liquid chamber to increase the pressure in the liquid chamber. And a system in which a heating element that generates heat when energized is provided in the liquid chamber and ink is discharged by increasing the pressure in the liquid chamber by bubbles generated by the heat generated by the heating element are widely known.
[0003]
In recent years, inkjet printers have been used in various applications due to the low cost and high image quality of inkjet printers and the spread of personal computers to general households. One of the major technical problems in ink jet printers is speeding up. For this problem, improvement of the driving frequency of active elements for ink ejection, increase in the number of nozzles and the number of heads, and the like are performed. In order to realize such high-speed printing, it is inevitable to increase the flow rate of ink supplied to the inkjet head.
[0004]
As the ink flow rate increases, it is necessary to reduce the resistance value of the flow path of the ink supply member that supplies ink to the inkjet head. The flow path of the ink jet head is designed in consideration of this resistance value, but there is a problem of air bubbles as another major factor to be considered. If there are bubbles in the flow path and the bubbles flow into the inkjet head during printing, the ink will not be ejected from the nozzles, resulting in an abnormal image.
[0005]
In addition to the bubbles mixed into the ink jet head, there is a filter part as described in Japanese Patent Application Laid-Open No. 11-277762 as a part where bubbles are a problem. The filter is provided in the ink flow path for the purpose of preventing poor printing due to fine dust from the upstream side flowing into the inkjet head. Normally, an ink-jet head having a filtration ability to take in particles of a few microns is almost 100% is used for the ink jet head. Therefore, the filter has a large fluid resistance.
[0006]
As described above, in order to achieve the supply of a large amount of ink, it is necessary to increase the filter size. However, the larger the filter, the worse the ink filling property and the more bubbles remain in the filter portion. When the bubbles come into contact with the filter to form a film, the ink does not flow through that portion, so that the fluid resistance increases and the ink supply amount becomes insufficient. Further, even if air bubbles pass through the filter during printing and flow into the ink jet head, the printing quality is adversely affected.
[0007]
[Problems to be solved by the invention]
  The present invention has been made in view of the above circumstances, and is intended to improve the ink filling property of the filter portion provided in the ink supply path of the inkjet head, and in particular, forms a large area filter. High-speed inkjet recording device with high reliability by ensuring good filling in the filter chamber, Droplet discharge device and image forming apparatusIt aims at realizing.
[0008]
The problems to be solved by the present invention are specifically listed below.
An intermediate member is provided in the filter chamber provided in the inkjet head to improve the ink filling property of the filter chamber.
By dividing the ink flow by the intermediate member in the filter chamber, the filling volume in the vicinity of the filter is reduced and the ink filling property is improved.
-The filling space of the filter chamber is separated by an intermediate member in the filter chamber to improve ink filling properties.
-By making the filling spaces in the vicinity of the filter substantially equal, the divided filling spaces are averaged and the filling property is improved.
-Helps bubbles to rise and prevents bubbles from remaining near the filter.
The time for ink to reach the filter along the filter chamber wall and the surface of the intermediate member is made substantially equal to improve the ink filling property of the filter chamber.
A filling method for satisfactorily filling a filter chamber with ink using an intermediate member having an ink flow suppressing function is provided.
・ Equally fill the entire surface of the filter by equalizing the distance between the intermediate member and the filter.
・ Ensuring good filling even when the filter chamber is large.
Provide a filling method for satisfactorily filling the filter chamber with ink using an intermediate member that causes a volume change in the filter chamber.
・ Improves fillability by reducing the filling space during filling.
-The filling space is reduced during filling to obtain good filling properties, and after filling, the filling space is enlarged to form a bubble trap space.
-Separating the filling space of the filter chamber to improve the ink filling property.
-The durability of the intermediate member is improved by reinforcing the contact portion of the intermediate member with the filter.
-Avoid blocking the ink supply path due to deformation of the intermediate member.
・ Improve the filling level by optimizing the liquid level during ink filling.
-Improve ink filling properties upstream of the intermediate member.
・ Narrow the filling space to improve filling properties.
・ Realize an intermediate member that is inexpensive and easy to assemble.
-Realize an inkjet head with high filling reliability.
Realize an inkjet recording apparatus that is highly reliable and capable of high-speed recording.
-Realize a filtering method and apparatus with good filling properties.
[0009]
[Means for Solving the Problems]
  The invention of claim 1 is an inkjet head that forms an image by ejecting ink in an ink liquid chamber from a nozzle, and has a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber, An intermediate member that divides the flow of ink to the filter chamber is provided upstream of the filter chamber.The intermediate member has a shape in which the path length reaching the filter from the upstream side through the filter inner wall is equal to the path length reaching the filter from the upstream side through the intermediate member.It is characterized by that.
[0011]
  Claim2The invention of claim1In the invention, the intermediate member is provided in contact with the filter.
[0012]
  Claim3The invention of claim1Or2In the invention, the intermediate member divides the volume of the filter chamber into approximately equal parts.
[0013]
  Claim4The invention of claim1Thru3In any one of the inventions, a space between the intermediate member and the filter is widened toward the downstream.
[0014]
  Claim5The invention of claim1Thru4In any one of the inventions, the surface of the intermediate member and the inner wall of the filter chamber are subjected to a hydrophilic treatment.
[0015]
  Claim6The invention of claim1Thru5In any one of the inventions, the space surrounded by the intermediate member, the inner wall of the filter chamber, and the filter is symmetrical with respect to the ink filling direction.
[0016]
  Claim7The invention of claim1Thru6In any one of the inventions, the wettability of the intermediate member is substantially equal to the wettability of the inner wall of the filter chamber.
[0017]
  The invention of claim 8 is an inkjet head that forms an image by ejecting ink in an ink liquid chamber from a nozzle, and has a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber, andWith pressure from outside the filter chamberAn intermediate member for changing the filling volume of the filter chamber, and when filling ink to supply ink to the ink liquid chamber through the filter in the filter chamber, the intermediate member reduces the filling volume on the upstream side of the filter in the filter chamber. It is characterized by making it.
[0018]
  Claim9The invention of claim8In the invention, the intermediate member is a member that expands and contracts, and the intermediate member contacts the filter during expansion.
[0019]
  Claim 10The invention of claim9In the invention, the intermediate member is characterized in that a reinforcing member is formed in a contact portion with the filter.
[0020]
  Claim 11The invention of claim8In the invention, the intermediate member is an elastic body formed on the wall surface of the filter chamber.
[0021]
  Claim 12The invention of claim8In the invention, the surface of the intermediate member or the inner wall of the filter chamber is formed with irregularities or grooves.
[0022]
  According to a thirteenth aspect of the present invention, in an ink jet head that forms an image by ejecting ink in an ink liquid chamber from a nozzle, the ink chamber has a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber, The intermediate member provided with a plurality of openings through which the upstream side of the filter in the filter chamberInk flow directionInMultipleProvided,The upstream diameter of the intermediate member is larger toward the upstream side,The ink in which the meniscus is formed in the opening is once held, and then the filter is filled with the ink.
[0023]
  Claim 14The invention of claim 13In the invention, the intermediate member has a plurality of openings, and an opening diameter of the openings is larger than an opening diameter of the filter.
[0024]
  Claim 15The invention of claim 13Or 14In the invention, the intermediate member is provided close to the filter.
[0025]
  Claim 16The invention of claim 1315In any one of the inventions, the intermediate member is provided in parallel to the filter.
[0027]
  Claim 17The invention of claim 13 to 16In any one of the inventions, the intermediate member is made of metal.
[0028]
  Claim 1828Or29The invention of claim 1 to 17One of the inkjet heads is mounted.
[0029]
  Claim19The invention is an ink jet head that forms an image by ejecting ink in an ink liquid chamber from a nozzle, and the ink is filled in an ink jet head having a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber In the ink filling method, an intermediate member that changes the filling volume of the filter chamber by pressure from the outside of the filter chamber is provided upstream of the filter of the filter chamber, and the ink filling operation is performed in a state where the intermediate member is expanded. And the ink filling operation is terminated after the intermediate member is contracted.
[0030]
  Claim 20The invention of claim19In the invention, the intermediate member is a member that expands and contracts, and the intermediate member is brought into contact with the filter during expansion.
[0032]
  Claim 21The present invention is an ink jet head that forms an image by ejecting ink in an ink liquid chamber from a nozzle, and the ink is filled in an ink jet head having a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber In the ink filling method, an intermediate member having a plurality of openings on the upstream side of the filter chamber has one side of the opening in close proximity to the filter, and the downstream side of the filter is negative at the start of ink filling. Ink is supplied to the intermediate member from the other side of the opening to form a meniscus on the one side of the opening, and then the negative pressure is increased to form ink that forms the meniscus. The filter is brought into contact with the filter.
[0033]
  Claim 22According to the present invention, in the filtering device that removes foreign matters in the liquid by passing the filter, an intermediate member that divides the flow of ink to the filter chamber is provided upstream of the filter in the filter chamber in which the filter is disposed. The intermediate member has a shape in which the path length reaching the filter from the upstream side through the filter inner wall is equal to the path length reaching the filter from the upstream side through the intermediate member. .
[0035]
  Claim 23In the filtering device for removing foreign matters in the liquid by passing the filter, the filling volume of the filter chamber is changed by the pressure from the outside of the filter chamber upstream of the filter in the filter chamber in which the filter is disposed. An intermediate member is provided, and when the liquid is filled in the filter chamber, the intermediate member reduces the filling volume on the upstream side of the filter in the filter chamber.
[0036]
  Claim 24The invention of claim 23In the invention, the intermediate member is a member that expands and contracts, and the intermediate member contacts the filter during expansion.
[0037]
  Claim 25The invention of claim 23In the invention, the intermediate member is an elastic body formed on the wall surface of the filter chamber.
[0038]
  Claim 26According to the invention, in the filtering method for removing foreign matters in the liquid by passing the filter, the volume of the filter chamber is changed by the pressure from the outside of the filter chamber upstream of the filter in the filter chamber in which the filter is disposed. An intermediate member is provided, filling of the liquid is started in a state where the volume of the filter chamber is reduced by the intermediate member, and then the volume of the filter chamber is increased.
[0041]
  Claim 27The invention of claim 26In the invention, the intermediate member is a member that expands and contracts, and the intermediate member is brought into contact with the filter during expansion.
[0043]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view of a main part of an ink jet recording apparatus to which the present invention is applied. FIG. 2 is a side view illustrating the internal structure of the ink jet recording apparatus shown in FIG. In the recording apparatus main body 1, the carriage 13 is movable in the main scanning direction (arrow A direction), an inkjet head 14 mounted on the carriage 13, an ink cartridge 15 for supplying ink to the inkjet head 14, and the like. The printing mechanism unit 2 and the like are accommodated, and a sheet feeding cassette (or a sheet feeding tray) 4 on which a large number of sheets 3 can be stacked from the front side is detachably attached to the lower part of the recording apparatus main body 1. In addition, the manual feed tray 5 for manually feeding the paper 3 can be opened and fed from the paper feed cassette 4 or the manual feed tray 5. The sheet 3 uptake, after recording a desired image by the print mechanism unit 2, and discharged to the discharge tray 6 attached to the rear side.
[0044]
The printing mechanism unit 2 holds the carriage 13 slidably in the main scanning direction (vertical direction in FIG. 2) with a main guide rod 11 and a sub guide rod 12 which are guide members horizontally mounted on left and right side plates (not shown). The carriage 13 is provided with an inkjet head 14 that ejects ink droplets of yellow (Y), cyan (C), magenta (M), and black (Bk), and a plurality of ink ejection ports crossing the main scanning direction. And are mounted with the ink droplet ejection direction facing downward.
[0045]
During recording, the inkjet head 14 is driven in accordance with the image signal while moving the carriage 13 to eject ink onto the stopped paper 3 to record one line, and after the paper 3 is conveyed by a predetermined amount, Record the line. Upon receiving a recording end signal or a signal that the trailing edge of the sheet 3 reaches the recording area, the recording operation is terminated and the sheet 3 is discharged.
[0046]
A recovery device 16 for recovering defective ejection of the inkjet head 14 is disposed at a position outside the recording area on the right end side in the movement direction of the carriage 13. As is well known, the recovery device 16 has a cap unit, a suction unit, and a cleaning unit. The carriage 13 is moved to the recovery device 16 side during printing standby, and the inkjet head 14 is capped by the capping means, and the ejection port portion is kept in a wet state to prevent ejection failure due to ink drying. Further, by ejecting ink that is not related to recording during recording or the like, the ink viscosity of all the ejection ports is made constant and stable ejection performance is maintained.
[0047]
When the ink cartridge is replaced or when a discharge failure occurs, the discharge port of the inkjet head 14 is sealed with a capping unit, and bubbles and the like are sucked out from the discharge port with the suction unit through the tube. And dust are removed by the cleaning means, and the ejection failure is recovered. The sucked ink is discharged to a waste ink reservoir (not shown) installed at the lower part of the main body and absorbed and held by an ink absorber inside the waste ink reservoir.
[0048]
FIG. 3 is an exploded view showing the basic configuration of the ink jet head according to the present invention, and FIG. 4 is a detailed sectional view taken along the line XX after assembly when the ink jet head shown in FIG. In the figure, 21 is a liquid chamber substrate, 22 is an electrode substrate, 23 is a nozzle plate, 24 is a power distribution member, 25 is a first member constituting an ink flow path, 26 is a second member constituting an ink flow path, 27 Is a filter, 28a and 28b are ink flow paths, 29 is a through hole for a power distribution member, 40 is an intermediate member, and the liquid chamber substrate 21 including a plurality of ink pressurizing chambers 32 is connected to the electrode substrate 22 as shown in FIG. The inkjet head unit 20 is formed by being bonded to the nozzle plate 23.
[0049]
The first member 25 of the ink supply member is joined to the back surface of the inkjet head, and ink is supplied from the ink flow path 28b to the pressurized liquid chambers 32 of both rows through the fluid resistance 31. One surface of the pressurized liquid chamber 32 also serves as the vibration plate 33, and as is well known, by applying a voltage signal to the electrode substrate 22 by the power distribution member 24, electrostatic attraction is generated between the electrode substrate 22 and the vibration plate 33. Occurs, the diaphragm 33 is displaced, the internal pressure of the pressurized liquid chamber 32 is changed, and ink is ejected from the nozzles 34.
[0050]
In order to reduce the size and increase the speed of this ink jet head, the number of nozzles inevitably increases, and as a result, the ink jet head has an elongated and flat structure as shown in FIG. The ink supply member is composed of two parts, a first member 25 and a second member 26, and a filter 27 is provided between them to form a filter chamber 35. Although various materials can be used for the ink supply members 25 and 26 forming the filter chamber 35, a resin material is excellent in terms of mass productivity and filter fixing. The filter 27 is provided for the purpose of preventing foreign matters in the ink from entering the inkjet head 20 and causing troubles such as nozzle clogging. Although a metal filter, a resin filter, or the like can be used for the filter 27, the metal filter is not only highly durable and inexpensive, but if the member to which the filter is fixed is made of resin, it is short due to heat welding or the like. It is preferable because it can be fixed in time and has excellent mass productivity.
[0051]
FIG. 5 is a simplified view of a cross section in the direction perpendicular to the filter surface of the filter chamber (a cross section along line YY in FIG. 3), but FIG. 5 is upside down from FIGS. 3 and 4. Ink flows from top to bottom. When the ink is filled with the filter chamber 35 almost empty, the ink flows into the filter chamber 35 mainly in the form of being transmitted through the inner wall 35a of the filter chamber 35 as shown in FIG. In the process of filling, the air in the filter chamber 35 is pushed out of the filter 27 and gradually replaced with ink. However, when the ink reaches the filter 27 when a large amount of air remains in the filter chamber 35, the surface of the filter is changed. Since the membrane is wetted at high speed by the capillary force, the air in the filter chamber 35 cannot pass through the filter 27. As a result, bubbles 36 remain on the upstream side of the filter 27 (FIG. 5B).
[0052]
If large bubbles 36 remain on the upstream side of the filter 27, a part of the bubbles 36 passes through the filter 27 and flows to the head unit 20 during printing, which may cause an abnormal image, as shown in FIG. As shown in the figure, if the filter 27 remains attached to the filter 27, the ink cannot pass through the bubble 36, so that the ink flow rate is insufficient when printing an image that consumes a large amount of ink, such as a solid image, It becomes an abnormal image. The most effective means for avoiding air bubbles remaining in the filter section is to reduce the filter area and the filter chamber volume.
[0053]
However, the former method has a problem in that the fluid resistance of the filter portion is increased, so that the ink flow rate necessary for high-speed printing cannot be secured. In the latter method, since the filter chamber capacity is small, the absolute amount of residual bubbles is small. However, as shown in FIG. 6, since the difference between the position near and far from the ink inlet is large, it can be completely filled. It is difficult, and the air bubbles 36 are likely to remain in a form adhered to the filter 27. When the air bubbles adhere to the filter 27, the ink does not flow in that portion, so that a substantial filter area is lost. As a result, the flow rate is insufficient in the high-speed printing described above.
[0054]
Further, as another method for improving the filling property, there is a method in which the filter is circular and ink is supplied to the central portion thereof. Compared to the case of a square filter having the same area, this method is easier to fill with ink more easily due to the symmetry of the filter chamber shape, but the area is large enough to accommodate an inkjet head compatible with high-speed printing. In this case, the filter installation space is less flexible than the rectangular filter, and as shown in FIG. 3, if it is directly fixed to the inkjet head, there is a demerit that the head becomes larger.
[0055]
In order to realize a small inkjet printer equipped with a large filter applicable to high-speed printing, the present invention improves the fillability of a filter chamber having a large filter, which is inherently difficult to fill well. Is to form an intermediate member in the filter chamber where the ink reaches the filter substantially simultaneously.
[0056]
FIG. 7 shows an example of the intermediate member 40 according to the present invention. In the illustrated example, the substantially rhombus-shaped intermediate member 40 is provided on the upstream side of the filter 27 in the filter chamber 35. By this intermediate member 40, the ink supplied to the filter chamber 35 is divided into two. This split flow substantially halves the space for filling, making the filter chamber a small size that is relatively easy to fill, and simultaneously making the filter 27 easily wet with ink. Therefore, the filling property is greatly improved.
[0057]
Further, in the configuration in which the filter chamber described in FIG. 6 is flattened and the filling volume is reduced, the bubbles 36 are likely to remain in a form attached to the filter 27. However, in the present invention, the height of the filter chamber is increased. Since the capacity of the filter chamber is reduced while keeping it high to some extent, even when the filter chamber is not completely filled, the bubbles 36 will remain in a form that floats away from the filter 27. The trouble can be avoided.
[0058]
In order to increase the effect of the diversion, there is a method in which the intermediate member 40 is fixed to the filter 27 in contact with each other as shown in FIG. By doing in this way, since the filling space of the upper part of the filter chamber 35 can be isolate | separated completely, a filling property improves further.
[0059]
7 and 8, the intermediate member 40 is arranged so as to divide the volume of the filter chamber 35 into two equal parts. In this way, filter chambers having different sizes are mixed without being divided equally. Then, since a difference occurs in the filling speed of each filter chamber, a large bubble remains on the side where the filling speed is slow, and it cannot be filled well. Regarding the shape of the intermediate member 40, for example, as shown in FIG. 9, when the surface of the intermediate member 40 that faces the filter 27 is horizontal, the air bubbles 36 sandwiched between the intermediate member 40 and the filter 27 are formed. It stays in that part and becomes easy to adhere to the filter 27.
[0060]
Accordingly, as shown in FIGS. 7 and 8, it is preferable that the space surrounded by the intermediate member 40 and the filter 27 is formed so as to become wider as the filter 27 is approached. By doing in this way, even when a bubble is generated between the intermediate member 40 and the filter 27, the bubble does not remain in that portion and moves upward by buoyancy. Therefore, the filling state which does not impair the flow rate can be obtained.
[0061]
Further, as described above, for the purpose of moving bubbles generated in the filter portion upward, a method of hydrophilizing the intermediate member 40 and the inner wall 35a of the filter chamber 35 by plasma treatment, ozone treatment, ashing, or the like is effective. It is. By making it hydrophilic, it becomes difficult for bubbles to stick to the intermediate member 40 and the inner wall 35a of the filter chamber, and the upward movement of the bubbles can be facilitated.
[0062]
Further, as the shape of the intermediate member 40, for example, a narrow one as shown in FIG. 10 is conceivable. However, in such a configuration, the ink path and the intermediate member 40 transmitted through the inner wall 35 a of the filter chamber 35 are arranged. Since the distance to the filter 27 is different in the transmitted ink path, it is difficult to wet the filter 27 almost simultaneously. As a result, uniform ink filling cannot be performed, and relatively large bubbles remain. Therefore, in order for the ink transmitted on the filter inner wall side 35a and the ink transmitted on the intermediate member 40 side to reach the filter substantially simultaneously, as shown in FIGS. 7 and 8, the intermediate member 40 and the filter inner wall 35a are used. The space surrounded by the filter 27 is preferably symmetrical with respect to the ink filling direction.
[0063]
Further, in order for the ink flowing along the inner wall 35a of the filter chamber 35 and the surface of the intermediate member 40 to reach the filter 27 at the same time, the flow rates of the ink moving on the filter chamber wall 35a and the intermediate member 40 should be equal. . For that purpose, a method of making the wettability the same by making the material and surface roughness of the filter inner wall 35a and the intermediate member 40 equal is effective.
[0064]
As described above, it is possible to reduce the effective filling volume by diverting the ink flowing into the filter chamber 35 using the intermediate member 40 and to realize good filling in a form in which the filter 27 is wetted substantially simultaneously. . In particular, a small inkjet head having a large number of nozzles capable of high-speed printing as shown in FIG. 3 is particularly effective when the filter chamber is directly fixed to the head.
[0065]
FIG. 11 is a diagram for explaining an example in which the filter chamber 35 is filled with ink using the intermediate member 41 having an action different from that of the diversion described above, and FIG. As shown in the drawing, an intermediate member 41 having a circular cross section is provided on the upstream side of the filter 27 in the filter chamber 35. The intermediate member 41 is, for example, a thin rubber tube, and in FIG. 11, a gas or liquid supply port is provided in a direction perpendicular to the paper surface, and has a function of changing the volume by taking in or out the gas or liquid. ing. Immediately before ink filling, as shown in FIG. 11B, the intermediate member 41 is expanded, and ink injection is started in this state. The ink may be injected by a method in which the ink is pushed away from the upstream side of the filter chamber 35 with a positive pressure, or a method in which the ink is sucked with a negative pressure from the downstream side of the filter chamber 35.
[0066]
In the recording apparatus shown in FIG. 1 and FIG. 2, the ink discharge surface of the head is capped by the recovery device 16, the inside of the cap is brought into a negative pressure state using a pump, and the ink jet head including the filter chamber is filled with ink. Yes. When filling with such a negative pressure suction method, the gas or liquid supply port is communicated with the atmosphere, and the tube member and the thickness are selected appropriately, so that the intermediate member 41 can be adjusted with the differential pressure between the suction negative pressure and the atmosphere. It is also possible to expand and contract. In this way, a means for putting gas or liquid in and out of the intermediate member 41 is unnecessary and effective. In the case of the present invention, since the filling space is filled and the filling volume is reduced by the expansion of the intermediate member 41, the ink is satisfactorily filled in the filter chamber 35.
[0067]
Next, the intermediate member 41 is gradually contracted while the ink injection operation is continued, and the ink injection operation is terminated after the contraction is completed. However, if the ink filling operation is completed before the contraction of the intermediate member 41 is completed, the inside of the head becomes a negative pressure relative to the outside, so that the ink flows backward and sucks air from the ink discharge port of the head. End up. Therefore, the volume increase / decrease of the intermediate member 41 is controlled in a form linked with the operation of the recovery device 16.
[0068]
Thus, by utilizing the volume change of the intermediate member 41, not only the effect of improving the filling property due to the small filling volume in the ink filling stage described above, but also the filter chamber volume increases after the filling operation is completed. Therefore, it is possible to provide a space in which the air bubbles 36 remaining during the filling operation rise above the filter chamber (FIG. 11C). Accordingly, when bubbles 36 remain in the filter chamber 35, the bubble remaining position can be set away from the filter 27, so that the bubbles 36 in the filter chamber 35 pass through the filter 27 and flow into the head during printing. In addition, problems such as non-ejection of ink can be avoided.
[0069]
When using the change in volume of the intermediate member, as shown in FIG. 12, if the intermediate member 41 is brought into contact with the filter 27 during expansion, the filter size is reduced during filling, so that the filling property is improved. . Thus, when the intermediate member 41 is brought into contact with the filter 27, there is a risk that the intermediate member 41 may be damaged by burrs of the filter 27, dust collected by the filter, or the like. Therefore, it is preferable to provide the reinforcing member 41a in the portion of the intermediate member 41 that contacts the filter 27. Various members such as a resin film and a rubber plate can be used as the reinforcing member 41a.
[0070]
As described above, when filling ink, it is desirable to increase the volume of the intermediate member as much as possible in order to reduce the filling space. However, as shown in FIG. If the supply path is interrupted, ink will not be filled. Therefore, as shown in FIG. 13, grooves and irregularities are preferably formed in the filter chamber inner wall 35 a or the surface of the intermediate member 41 so that ink is supplied even when the intermediate member 41 is greatly expanded.
[0071]
FIG. 14 is a diagram showing an example in which an elastic body 42 is provided on a part of the inner wall of the filter chamber 35 as an intermediate member. In this case, as shown in FIG. 14B, a pressure rod 51 is inserted from the outside. For example, the elastic body (intermediate member) 42 is deformed to be filled with ink, and after filling, the same effect as in the case where the volume of the intermediate member 41 itself is changed is obtained by returning to the state of FIG. Obtainable. The deformation means of the elastic body 42 is not limited to that shown in FIG. 14, and air pressure or the like can also be used. Further, in the case of the negative pressure suction filling method, the elastic body can be deformed by the differential pressure between the suction negative pressure and the atmosphere by appropriately selecting the elastic modulus and the like of the elastic body 42, so that it is shown in FIG. A similar effect can be obtained with a configuration without the pressure rod 51.
[0072]
FIG. 15 is a diagram for explaining an example in which the filter chamber 35 is filled using the intermediate member 43 having a function of suppressing the ink flow. The intermediate member 43 has a hole having a larger opening than the filter 27. The intermediate member 43 is provided on the upstream side of the filter 27 at a position separated by a minute distance d from the filter 27. When ink is supplied to the filter chamber 35 having such a configuration by performing a first filling operation with a relatively small pressure, the ink first reaches a position indicated by A in FIG. At this position A, the opening of the intermediate member 43 is large, so that the meniscus holding force is small and cannot be blocked, so that the ink flows through the hole of the intermediate member 43 and the downstream end of the intermediate member 43 (position indicated by B). To reach. If the filling pressure at this time is too large, the ink flows out to the filter unit 27 as it is, but by setting the filling pressure appropriately, the pressure loss is caused by the resistance of the hole in the intermediate member 43. The ink holds the meniscus at the downstream end of the intermediate member 43, and the liquid level can be stopped as shown in FIG.
[0073]
Next, when the pressure is increased at once in the second filling operation, the meniscus at the downstream end of the intermediate member 43 is broken, and the ink flows out from the entire surface of the intermediate member 43 toward the filter 27 while pushing out air. Therefore, it is possible to create a state in which the entire surface of the filter 27 is wetted by ink almost simultaneously, and a good filling state can be obtained.
[0074]
In the case of the method shown in FIG. 15, the aim is to make the ink blocked in the intermediate member 43 in the second filling operation reach the entire surface of the filter almost simultaneously, so the downstream end of the intermediate member 43 is It is desirable to be parallel to the filter 27. If it is provided with a large inclination, the ink reaches the filter 27 at a portion where the distance between the two is short, and an ink film is formed on the filter while the ink is insufficiently filled. It tends to result in residual air bubbles. In addition, when the ink once held by the intermediate member 43 is flowed downstream and filled in the second filling operation, if the distance between the filter 27 and the intermediate member 43 is large, the ink hardly reaches the entire surface of the filter 27 at the same time. Thus, poor filling is likely to occur. Therefore, it is desirable that the distance between the intermediate member 43 and the filter 27 be close enough that the liquid surface does not touch the filter 27 when the ink is held on the intermediate member 43.
[0075]
In FIG. 15, the diameter of the hole formed in the intermediate member 43 is constant from the upstream side to the downstream side, but as shown in FIG. 16, the upstream side diameter may be larger than the downstream side diameter. good. Good filling can be performed by optimizing the diameter and length of the hole formed in the intermediate member by the pressure in the first and second filling operations, the size of the intermediate member, and the like.
[0076]
FIG. 17 shows a plurality of intermediate members 43 having a function of suppressing the flow of ink as described above (for example, 43₁, 43₂, 43_Three, 43_FourFIG. 17 is a diagram showing the provided configuration, and as shown in FIG. 17, the opening (hole diameter) of the intermediate member 43 becomes larger toward the upstream side of the ink flow. Further, the size (width) of the intermediate member is smaller toward the upstream. In FIG. 17, there are four intermediate members (43 on the upstream side of the filter 27).₁~ 43_FourThe filter chamber 35 is satisfactorily filled by performing the filling operation sequentially while increasing the filling pressure in five stages. In this configuration, the filter chamber is partitioned by the intermediate member into a small space, so that the filling property at each portion can be remarkably improved.
[0077]
Although various materials can be used for the intermediate member, a metal filter is desirable in consideration of cost and assemblability. The metal mesh has a wide aperture ratio selectivity, and can easily produce a filter part in a desired shape by punching, and can easily perform a surface treatment or the like. Further, fixing to the filter chamber can be easily performed in a short time by heat welding or the like.
[0078]
Although the electrostatic ink jet has been described above as an example, the present invention is also effective for an ink jet head of another printing method such as a piezoelectric method or a bubble jet method. The present invention is mainly used for an ink filter device of an ink jet printer, but is not limited thereto, and can be applied to, for example, a filter device used for a hydraulic device or the like.
Below, it demonstrates in detail based on a specific Example.
Example 1
Referring to FIGS. 3 and 4, a silicon substrate having a thickness of 200 [μm] was used as the liquid chamber substrate 21, and a borosilicate glass having a thickness of 1 [mm] was used as the electrode substrate 22. A boron layer corresponding to the thickness of the vibration plate 33 was previously formed on one surface of the silicon substrate on the liquid chamber substrate 21, and the vibration layer 33 was formed by wet etching by using this boron layer as an etching stop layer. Further, the electrode substrate 22 is formed by patterning a Ni electrode by sputtering in a groove formed by wet etching, and SiO as an electrode protective film on the electrode.₂The layer was formed by sputtering. In addition, a through hole was formed in the central portion of the electrode substrate 22 by blasting to form an ink flow path.
[0079]
Next, the positions of the electrodes of the substrates 21 and 22 and the position of the diaphragm 33 are accurately positioned, and both are joined by anodic bonding, and then a through hole as an ink flow path is formed in the center of silicon by dry etching. Formed. In this way, the electrostatic actuator 20a having the ink flow path 28 in the center portion was formed with two rows of staggered diaphragms at 150 dpi. Next, the nozzle plate 23 in which the nozzle 34 and the fluid resistance portion 31 were integrally formed by an electroforming method was joined to the actuator 20a using an adhesive to form the ink jet head 20 having about 400 nozzles.
[0080]
An ink supply member 25 made of a resin material was bonded to the back surface of the electrode substrate 22 of the inkjet head 20. As shown in FIG. 3, the ink supply member includes a first member 25 and a second member 26, and a filter 27 is included between them. The filter 27 is of a stainless twill woven type, and has a rectangular shape of 4 mm × 35 mm with a filtration accuracy of about 5 [μm], and is fixed to the first member 25 by heat welding. FIG. 5A shows a longitudinal sectional view (YY line in FIG. 3) of the filter chamber 35 of the ink supply member. The filter chamber 35 has a substantially quadrangular pyramid shape on both the upstream and downstream sides of the filter 27, and the heights h1 and h2 are 7.5 mm and 2 mm, respectively. Both members were made of a transparent acrylic resin for evaluation of ink filling properties.
[0081]
When the suction device is mounted on the nozzle surface with the ink jet head as described above and suction is performed for 5 cc at a pressure of about −5 [kPa], the filter portion 27 of the ink supply member is observed, and FIG. ), Large bubbles 36 remained on the upper portion of the filter 27. In this state, when a solid image printing durability test was performed using the ink jet recording apparatus shown in FIG. 1, there was a problem that an abnormal image called white streak was generated.
[0082]
Next, as shown in FIG. 6, when the volume of the filter chamber 35 was changed to a head having a small volume and ink filling was performed in the same manner, the bubbles themselves decreased as shown in FIG. 36 remained in the form of sticking to the filter 27. When this head was mounted on a printer and a solid image printing durability test was performed, an abnormal image similar to the previous one was generated.
[0083]
Next, as shown in FIG. 7, an ink jet head is assembled using an ink supply member in which an intermediate member 40 having a rhombus shape is formed in the central portion on the upstream side of the filter 27, and ink filling and printing are performed under the same conditions as described above. Evaluation was performed. The intermediate member 40 is also made of acrylic resin. As a result, although the air bubbles 36 remain in the filter chamber 35 after filling, the size is remarkably small compared to the air bubbles in the configuration in which the intermediate member 40 is not provided, and as shown in FIG. It remained in the form of floating in the middle. Even in the printing evaluation, good results were obtained without generating abnormal images.
[0084]
9 and 10 were used for the shape of the intermediate member 40, and a comparative experiment was performed. In the configuration shown in FIG. 9, the size of the bubble itself was small. The result was that bubbles 36 remained on the lower side of 40. Since the bottom surface of the intermediate member 40 is horizontal, the bubbles do not move upward and remain in contact with the filter 27, so an abnormal image is generated in the printing evaluation. Further, in the configuration of FIG. 10, a good result was obtained in the printing evaluation, but the remaining bubbles were larger than those in the configuration of FIG.
[0085]
Next, the position of the intermediate member 40 was moved in the horizontal direction and the vertical direction, and the influence on the filling property was examined. First, when the intermediate member 40 is shifted in the horizontal direction, as shown in FIG. 18, the filling property on the side where the intermediate member 40 is close was good, but large bubbles 36 remained on the opposite side. Further, when the intermediate member 40 is lowered from the position shown in FIG. 7 so that the intermediate member 40 contacts the filter 27, the size of the remaining bubbles 36 is further reduced as shown in FIG.
[0086]
Next, in order to investigate the influence of the wettability of the member, there are two types of the structure shown in FIG. Prepared for comparative evaluation. As a result, in the sample subjected to the hydrophilic treatment, as shown in FIG. 8, small bubbles 36 floated and remained above the filter chamber 35, and the result was satisfactory. As shown in the figure, bubbles 36 may stick to the intermediate member 40 or the inner wall 35a of the filter chamber 35 and may not float upward, and may remain in the vicinity of the filter 27 at an undesirable position.
[0087]
Furthermore, when the intermediate member 40 was changed to a metal and a structure with a difference in wettability between the intermediate member 40 and the surface of the filter chamber inner wall 35a was obtained, the remaining air bubbles increased slightly.
[0088]
The above experiment confirmed the effect of providing the intermediate member 40 on the upstream side of the filter 27 in order to satisfactorily fill the large filter chamber. Even if the intermediate member 40 is provided, the air bubbles 36 may remain depending on the shape, size, and the like of the filter chamber 35. However, by making the shape, position, wettability, etc. of the intermediate member 40 appropriate, the printing characteristics are adversely affected. It is possible not to give.
[0089]
In the above embodiment, only the configuration in which the filter chamber 35 is divided into two parts has been described. However, in particular, when the filter size is larger, it is preferable that the filter 27 is divided into two or more parts so that the ink wets the filter 27 almost simultaneously. Filling can be realized.
[0090]
(Example 2)
Next, a second embodiment of the present invention will be described with reference to FIGS. A silicon substrate was used as the liquid chamber substrate 21, and the diaphragm 33 was formed by anisotropic etching. At this time, a boron layer corresponding to the thickness of the vibration plate 33 is formed on one surface of the silicon substrate 21 in advance, and the pressure layer chamber 32 provided with the vibration plate 33 on one surface is formed by using this boron layer as an etching stop layer. Formed. At the same time, the ink channel 28 was also etched in the center to form a groove. A silicon substrate was also used as the electrode substrate 22, and a shallow groove having a depth of 1 μm or less was formed by etching at a position corresponding to the vibration plate 33 of the liquid chamber substrate 21, and a TiN electrode was formed at the bottom of the groove. In addition, the region facing the liquid chamber substrate 21 on the upper surface of the electrode has SiO as a protective layer for the electrode.₂A film was formed. After the electrode substrate 22 and the liquid chamber substrate 21 are bonded together by a direct bonding method, the center groove corresponding to the ink flow path is processed by wet etching and dry etching from the back surface of the electrode substrate 22 to penetrate therethrough. 20a was formed.
[0091]
The nozzle plate 23 is formed by a Ni electroforming method, and is provided with a nozzle 34 having a diameter of about 25 [μm], a fluid resistance 31 having a width of 70 [μm], a length of 600 [μm], and a depth of 20 [μm]. A water repellent film was formed on the surface side by a eutectoid plating method of Ni and PTFE. Subsequently, a two-component curable epoxy adhesive was applied to the non-water-repellent surface of the nozzle plate 23 as a thin film, and adhesively cured to the pressurized liquid chamber 32 side of the actuator member 20a. An FPC is used as the power distribution member 24 that transmits an electrical signal for driving the actuator 20a, and is joined to an electrode pad provided at an end of the electrode substrate 22 via an ACF. Finally, the actuator member 20a was bonded to the ink supply member 25, and the inkjet head 20 was assembled.
[0092]
In the ink supply members 25 and 26, as shown in FIG. 11A, a filter chamber having a filter 27 at the center was formed. As the filter 27, a rectangular stainless twilled weave type having a size of 4 mm × 35 mm and having a filtration accuracy of about 5 [μm] was used. The shape of the filter chamber 35 is the same as that shown in FIG. 5A described in Example 1, and is made of a transparent acrylic resin. In addition, a hole having a diameter of about 5 mm is formed in a substantially central portion of the filter chamber 35 upstream of the filter 27 (upper side in FIG. 11A), and a rubber tube rich in elasticity is inserted as an intermediate member 41 in the same portion. Both ends were connected to a pump (not shown). With such a configuration, the intermediate member 41 can be freely set in an expanded state shown in FIG. 11B and a contracted state shown in FIG.
[0093]
In the present embodiment, a rubber material having a thickness of 100 microns or less is used for the intermediate member 41, and the diameter thereof is about 7 mm when expanded and about 5 mm when contracted, but a thin resin film may be used. An intermediate member 41 having a similar volume change function can be formed. In the ink jet head having such a configuration, a suction device was mounted on the nozzle surface, and ink was filled in a sequence as shown in FIG.
[0094]
In FIG. 20, t1, t2, and t3 are 5 seconds, 10 seconds, and 5 seconds, respectively. By driving the intermediate member 41 and the suction device in such a sequence, as shown in FIG. 11B, the filling volume is narrowed at the ink filling stage, and after filling, the filling volume is widened so that there is no bubble adhesion. Good filling can be realized.
[0095]
Also in the result of the filling experiment with the ink jet head of this example, as shown in FIG. 11C, small bubbles 36 remained in the filter chamber 35, but separated from the filter 27, which did not affect the printing characteristics. It was a form floating at the position, and a good filling state could be obtained.
[0096]
In the filling sequence in FIG. 20, for the sake of comparison, the same evaluation was performed with t1 and t2 set to zero. In both cases, the remaining bubbles increased, which was not good compared to the case of the sequence in FIG. It was. When the cause is analyzed by observing the filling process, if t1 is short, ink filling is started before the intermediate member 41 is fully expanded, so that the filling volume is large and the ink is difficult to reach the filter 27 at the same time. It has been found. Further, when t2 is small, the filter chamber 35 is once satisfactorily filled, but it turns out that the phenomenon of sucking bubbles from the nozzle side occurs as the ink flows backward while the suction device stops and the intermediate member 41 contracts. did.
[0097]
Although the appropriate values of t1, t2, and t3 differ depending on the configuration of the filter chamber 35 and the intermediate member 41, the characteristics of the suction device, and the like, the drive sequence of the intermediate member and suction device is as shown in FIG. When the maximum volume is reached, ink filling is started, and the suction operation is stopped after the intermediate member 41 is contracted, so that a good filling state can be obtained.
[0098]
The intermediate member 41 according to the present embodiment is volume-expanded at the time of filling, so that the ink filling volume is reduced and the filling property is improved. Therefore, the pressure applied to the intermediate member 41 was increased, and the fillability was evaluated by expanding the intermediate member 41 to fill the filter chamber 35 as shown in FIG. As a result, unexpectedly large bubbles remained. It has been found that the cause is that the intermediate member 41 is excessively expanded and the intermediate member 41 blocks the ink supply path above the filter chamber 35. Therefore, a protrusion having a height of about 0.2 mm is appropriately disposed and fixed on the surface of the intermediate member 41, and even if the intermediate member 41 comes into contact with the filter inner wall surface on the ink supply side, an ink supply path corresponding to the height of the protrusion. As a result, even when the intermediate member 41 was expanded to the maximum, the ink supply was not cut and a good filling state could be obtained.
[0099]
In this embodiment, the volume of the intermediate member 41 changes. However, as shown in FIG. 14, a part of the filter chamber wall is used as an elastic member to form an intermediate member 42, and the intermediate member 42 is deformed to reduce the filling volume. The filling property can be improved similarly by the changing method.
[0100]
(Example 3)
FIG. 12 shows another embodiment of the intermediate member whose volume changes. In the filter chamber 35 of the present embodiment, as shown by a dotted line in FIG. 12, the intermediate member 41 has a substantially elliptical cross-sectional shape (long side 5 mm, short side 3 mm), and is provided at a position slightly close to the filter 27. Yes. When the ink supply member having the filter chamber 35 is mounted on the same ink jet head as that of the second embodiment and air is supplied to the intermediate member 41 and expanded, the intermediate member 41 expands as shown by a solid line in FIG. The lower surface of the filter 27 comes into contact with the filter 27 and closes about 1/3 of the opening of the filter 27.
[0101]
When the suction operation was performed in the sequence of FIG. 20 and the ink filling property was evaluated, the size of the residual bubbles was smaller than the result of Example 2. However, when the endurance test of the intermediate member 41 was carried out by repeating the filling evaluation, a problem that the intermediate member 41 was damaged occurred. It has been found that the cause is that dust accumulated on the filter surface due to many fillings pierced the intermediate member 41. Therefore, the rubber material 41a is laminated only on the lower surface of the intermediate member 41, and the contact portion with the filter 27 is changed to a double thickness. After such a change, the same durability evaluation was performed. As a result, there was no problem that the intermediate member 41 was damaged, and good filling could be performed over a long period of time.
[0102]
(Example 4)
FIG. 15 is for explaining another embodiment of the present invention, and an example in which an intermediate member 43 having a function of suppressing the flow of ink is provided on the upstream side of the filter 27 of the filter chamber 35 formed of acrylic resin. Is shown. This intermediate member 43 is a resin plate having a thickness of 4 mm in which a large number of holes of about 500 microns in diameter are drilled perpendicularly to the filter 27 inside, and is bonded and fixed to the inner wall of the filter chamber 35 with a gap of 1 mm parallel to the filter 27. Has been. Note that the height of the space above the intermediate member 43 was set to about 1 mm. The filter 27 is the same as that used in the first to third embodiments.
[0103]
The ink supply member having the filter chamber 35 was connected to the same inkjet head 20 as in Example 2, and the nozzle surface was capped and suctioned and filled by a suction device. The suction device was operated in a sequence as shown in FIG. First, time t4 suction is performed at the pressure P1. By this suction operation, ink flows into the space above the intermediate member 43. At this time, since the hole diameter of the intermediate member 43 is large, unlike the fine mesh filter, the film is not stretched at the portion indicated by A in FIG. Was narrowed to about 1 mm, so that the space was filled with ink relatively well.
[0104]
Although the ink flows inside the intermediate member 43, due to the pressure loss due to the fluid resistance of the intermediate member 43, the ink does not flow in the form of holding the meniscus at the downstream end of the intermediate member indicated by B in FIG. The state of B) was maintained. Next, as shown in FIG. 21, when suction is performed with a negative pressure P2 larger than P1, the meniscus formed at the downstream end of the intermediate member 43 is broken, and the ink flows out from the entire surface of the intermediate member 43, and the filter The space between the intermediate member 43 and the filter 27 was satisfactorily filled with ink in a form in which 27 was wetted simultaneously.
[0105]
The parameters P1, P2, t4, and t5 in the suction sequence vary greatly depending on the filter specifications, the material and shape of the filter chamber and the intermediate member, ink physical properties, and the like. In this embodiment, P1 = -3 kPa, t4 = 10 s. , P2 = −30 kPa, t5 = 15 s. In the filter chamber of this configuration, the ink is temporarily blocked by the intermediate member 43 provided in the vicinity of the filter 27, and ink is poured out from the entire surface of the intermediate member 43 to fill the filter portion. Therefore, if the intermediate member 43 is provided to be inclined with respect to the filter, filling failure tends to occur.
[0106]
Further, even if the distance between the filter 27 and the intermediate member 43 is too large, the filling space above the filter is widened and it is difficult to fill. On the other hand, if the interval is too small, the meniscus formed on the lower surface of the intermediate member 43 comes into contact with the filter 27. When the meniscus comes into contact with the filter 27, the ink wets the surface of the filter with the capillary force from that portion, which tends to cause poor filling. In the filter chamber 35 shown in the embodiment, the appropriate distance between the intermediate member 43 and the filter 27 is about 0.5 to 1.5 mm.
[0107]
FIG. 17 is a view showing a modification of the embodiment shown in FIG. 15. In FIG. 17, the shape of the upstream side of the filter chamber 35 is a substantially quadrangular pyramid shape, and four intermediate members 43 are formed in the same portion.₁~ 43_FourWere formed in parallel. Here, a metal mesh that is inexpensive and easy to process was used as the intermediate member, and the opening gradually decreased from the upstream side toward the downstream side, and fixed by heat welding. As shown in FIG. 22, the suction is performed in such a manner that the suction pressure is gradually increased from P1. By performing such filling, each intermediate member 43₁~ 43_FourThus, the layered filling space could be filled steadily and sequentially while blocking the ink. Such a configuration in which a plurality of intermediate members are stacked is effective for a large filter chamber.
[0108]
(Example 5)
FIG. 23 is a view for explaining still another embodiment of the present invention. The wall forming the filter chamber 35 on the upstream side of the filter 27 is made of a rubber material (first intermediate member 42) having a thickness of about 0.2 mm. And a resin plate (second intermediate member 43) having a thickness of 4 mm, in which a large number of holes having a diameter of about 500 microns perpendicular to the filter 27 were drilled, was provided in parallel with the filter 27 with a gap of 1 mm. The filter 27 used was the same as in Examples 1-3. On the other hand, a pressure member 51 that pressurizes the first intermediate member 44 made of a rubber material provided as a part of the wall of the filter chamber 35 from the outside is formed of a resin material, and is applied to the ink supply member 26 by a solenoid actuator (not shown). A configuration that can be taken in and out.
[0109]
The ink supply member having the filter chamber 35 was connected to the same ink jet head as in Example 2, and after capping the nozzle surface, the ink was filled by suction with a suction device as shown in FIG. First, before the ink is filled, the pressure member 51 is pushed in, the elastic wall as the first intermediate member 42 is deformed inward to reduce the filling space (arrow a in FIG. 24), and then the ink is sucked at the pressure P1. (FIG. 24 arrow b). In this embodiment, P1 = −3 kPa. By this filling, the ink flowed to the lower surface of the second intermediate member 43, where the meniscus was stretched to stop the filling (FIG. 23B). Subsequently, the second suction is performed at the pressure P2 (in this embodiment, −30 kPa) (arrow c in FIG. 24), and the pressurizing member 51 is released after 10 seconds (arrow d in FIG. 24). The suction operation was terminated after the member 42 returned to the initial state. As a result, as shown in FIG. 23C, bubbles did not adhere to the filter portion 27, and a good filling state was obtained.
[0110]
In the configuration of the present embodiment, the substantial volume of the filter chamber at the time of filling is reduced by the deformation of the first intermediate member 42 and the liquid level holding of the second intermediate member 43 so that ink can be simultaneously poured into the filter 27 portion. Therefore, good ink filling could be realized. Further, when the pressurizing member 51 is released, a flow indicated by an arrow A in FIG. 23C is generated on the upper part of the filter, so that the bubble trap space 46 generated by the release of the pressurizing member 51 is adjacent to the filter. The remaining air bubbles 36 can be positively pushed out, and reliable filling becomes possible.
[0111]
【The invention's effect】
  The invention of claim 1 is an inkjet head that forms an image by ejecting ink in an ink liquid chamber from a nozzle, and has a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber, Upstream of the filter chamberDividing the flow of ink into the filter chamberIntermediate memberHaveBecause I tried toReduce the filling volume near the filter,The ink filling property of the filter part of an inkjet head can be improved.
[0113]
  Claim2The invention of claim1In this invention, since the intermediate member is provided in contact with the filter, the filling space of the filter chamber is separated, and the ink filling property can be improved.
[0114]
  Claim3The invention of claim1Or2In the invention, since the intermediate member divides the volume of the filter chamber into approximately equal parts, the divided filling spaces can be averaged and the filling property can be improved.
[0115]
  Claim4The invention of claim1Thru3In any one of the inventions, since the space between the intermediate member and the filter is widened toward the downstream, it is possible to promote the rise of bubbles and prevent the bubbles from remaining in the vicinity of the filter.
[0116]
  Claim5The invention of claim1Thru4In any one of the inventions, since the hydrophilic treatment is applied to the surface of the intermediate member and the inner wall of the filter chamber, it is possible to promote the rise of the bubbles and prevent the bubbles from remaining in the vicinity of the filter.
[0117]
  Claim6The invention of claim1Thru5In any of the inventions, the space surrounded by the intermediate member, the inner wall of the filter chamber, and the filter is symmetrical with respect to the ink filling direction, so that the ink is filtered along the filter inner wall and the surface of the intermediate member. Can be made substantially equal to each other, and the ink filling property of the filter chamber can be improved.
[0118]
  Claim7The invention of claim1Thru6In any of the inventions, since the wettability of the intermediate member is substantially equal to the wettability of the inner wall of the filter chamber, the time for the ink to reach the filter along the filter chamber inner wall and the surface of the intermediate member is substantially equal, The ink filling property of the filter chamber can be improved.
[0119]
  The invention of claim 8 is an inkjet head that forms an image by ejecting ink in an ink liquid chamber from a nozzle, and has a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber, andWith pressure from outside the filter chamberAn intermediate member for changing the filling volume of the filter chamber, and when filling ink to supply ink to the ink liquid chamber through the filter in the filter chamber, the intermediate member reduces the filling volume on the upstream side of the filter in the filter chamber. Therefore, the filling space can be reduced during filling to obtain good filling properties, and after filling, the filling space can be enlarged to form the bubble trap space.
[0120]
  Claim9The invention of claim8In this invention, the intermediate member is a member that expands and contracts. Since the intermediate member contacts the filter during expansion, the filling volume is reduced and the filling space of the filter chamber is separated. The filter size can be reduced, and the ink filling property is improved.
[0121]
  Claim 10The invention of claim9In this invention, since the reinforcing member is formed in the contact portion between the intermediate member and the filter, the durability of the intermediate member is improved.
[0122]
  Claim 11The invention of claim8In this invention, since the intermediate member is an elastic body formed on the wall surface of the filter chamber, the filling space at the time of filling can be reduced with a simple configuration, and the filling property is improved.
[0123]
  Claim 12The invention of claim8In this invention, since the unevenness or the groove is formed on the surface of the intermediate member or the inner wall of the filter chamber, it is possible to avoid the blockage of the ink supply path due to the deformation of the intermediate member.
[0124]
  According to a thirteenth aspect of the present invention, in an ink jet head for forming an image by ejecting ink in an ink liquid chamber from a nozzle, the ink chamber has a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber, and the ink An intermediate member provided with a plurality of openings is provided on the upstream side of the filter in the filter chamber, and the ink having the meniscus formed therein is once held, and then the ink is filled in the filter. The filling level can be improved by optimizing the liquid level.Furthermore, since a plurality of the intermediate members are provided in the ink flow direction and the opening diameter of the intermediate member is larger toward the upstream side, good filling properties can be ensured even when the filter chamber is large.
[0125]
  Claim 14The invention of claim 13In the invention, the intermediate member has a plurality of openings, and the opening ratio of the openings is larger than the opening ratio of the filter. Therefore, it is difficult to form a film on the upstream surface of the intermediate member, and the intermediate member upstream side. The ink filling property of the ink is improved.
[0126]
  Claim 15The invention of claim 13Or 14In this invention, since the intermediate member is provided close to the filter, the filling space is narrowed and the ink filling property is improved.
[0127]
  Claim 16The invention of claim 1315In any one of the inventions, since the intermediate member is provided in parallel to the filter, the gap between the intermediate member and the filter can be made equal to perform filling uniformly from the entire surface of the filter, and the filling property is improved.
[0129]
  Claim 17The invention of claim 13 to 16In any one of the inventions, since the intermediate member is made of metal, an intermediate member that is inexpensive and has good assemblability can be realized.
[0130]
  Claim 18The present invention relates to an ink jet recording apparatus.7Since the ink jet head according to any one of the above is mounted, the ink jet recording apparatus comprises:7The effects described in (1) can be achieved.
  Similarly, claim 28Or29The invention of claim 1 to 17Since the ink jet head according to any one of the above is mounted,7The effects described in (1) can be achieved.
[0131]
  Claim19The present invention is an ink jet head that forms an image by ejecting ink in an ink liquid chamber from a nozzle, and the ink is filled in an ink jet head having a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber In the ink filling method, an intermediate member that changes the filling volume of the filter chamber by pressure from the outside of the filter chamber is provided on the upstream side of the filter of the filter chamber, and the ink filling operation is performed while the intermediate member is expanded. Since the ink filling operation is terminated after the intermediate member is contracted, the filling space is reduced during filling to obtain good filling properties, and after filling, the filling space is enlarged to increase the bubble trap. A space can be formed.
[0132]
  Claim 20The invention of claim19In this invention, the intermediate member is a member that expands and contracts, and the intermediate member is brought into contact with the filter at the time of expansion. Therefore, the filling space of the filter chamber is separated and the filling volume is reduced. The effective filter size can be reduced, and the ink filling property is improved.
[0134]
  Claim 21The present invention is an ink jet head that forms an image by ejecting ink in an ink liquid chamber from a nozzle, and the ink is filled in an ink jet head having a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber In the ink filling method, an intermediate member having a plurality of openings on the upstream side of the filter chamber has one side of the opening in close proximity to the filter, and the downstream side of the filter is negative at the start of ink filling. Ink is supplied to the intermediate member from the other side of the opening to form a meniscus on the one side of the opening, and then the negative pressure is increased to form ink that forms the meniscus. Since the filter is in contact with the filter, the gap between the intermediate member and the filter can be made equal so that ink can be uniformly filled from the entire surface of the filter. Sex can be improved.
[0135]
  Claim 22In the filtering device that removes foreign matters in the liquid by passing the filter, an intermediate member that divides the flow of the liquid to the filter chamber is provided upstream of the filter in the filter chamber in which the filter is disposed. The intermediate member has a shape in which the path length reaching the filter through the filter inner wall from the upstream side and the path length reaching the filter from the upstream side are equal to each other. The filter liquid filling property can be improved.
[0137]
  Claim 23In the filtering device for removing foreign matters in the liquid by passing the filter, the filling volume of the filter chamber is changed by the pressure from the outside of the filter chamber upstream of the filter in the filter chamber in which the filter is disposed. An intermediate member to be used, and when filling the filter chamber with liquid, the intermediate member reduces the filling volume on the filter upstream side of the filter chamber, thereby reducing the filling space during filling and obtaining good filling properties. A bubble trap space can be formed by enlarging the filling space after filling.
[0138]
  Claim 24The invention of claim 23In this invention, the intermediate member is a member that expands and contracts. Since the intermediate member contacts the filter during expansion, the filling volume is reduced, the filling space of the filter chamber is separated, and an effective filter at the time of filling is obtained. The size can be reduced, and the liquid filling property is improved.
[0139]
  Claim 25The invention of claim 23In this invention, since the intermediate member is an elastic body formed on the wall surface of the filter chamber, the filling space at the time of filling can be reduced with a simple configuration, and the filling property is improved.
[0140]
  Claim 26According to the invention, in the filtering method for removing foreign matters in the liquid by passing the filter, the volume of the filter chamber is changed by the pressure from the outside of the filter chamber upstream of the filter in the filter chamber in which the filter is disposed. Since the filling of the liquid is started in a state where the intermediate member has the volume of the filter chamber reduced by the intermediate member and then the volume of the filter chamber is increased, the filling space is reduced at the time of filling. It is possible to obtain a filling property and enlarge the filling space after filling to form a bubble trap space.
[0143]
  Claim 27The invention of claim 26In this invention, the intermediate member is a member that expands and contracts, and the intermediate member is brought into contact with the filter during expansion, so that the filling volume is reduced and the filling space of the filter chamber is separated, and an effective filter at the time of filling is obtained. The size can be reduced, and the liquid filling property is improved.
[Brief description of the drawings]
FIG. 1 is a perspective view of a main part configuration of an ink jet recording apparatus to which the present invention is applied.
2 is a side configuration diagram for explaining an internal configuration of the ink jet recording apparatus shown in FIG. 1; FIG.
FIG. 3 is an exploded view of a basic configuration of an inkjet head according to the present invention.
4 is a detailed cross-sectional view after assembly when the inkjet head shown in FIG. 3 is of an electrostatic drive type.
FIG. 5 is a simplified diagram of a cross section in a direction perpendicular to the filter surface of the filter chamber.
FIG. 6 is a view showing a modification of the filter chamber.
FIG. 7 is a view showing an example of an intermediate member according to the present invention.
FIG. 8 is a view showing a method of fixing an intermediate member to a filter in a contact state.
FIG. 9 is a view showing a modification of the intermediate member.
FIG. 10 is a view showing another modification of the intermediate member.
FIG. 11 is a view for explaining another embodiment of the intermediate member according to the present invention.
FIG. 12 is a view for explaining another embodiment of the intermediate member according to the present invention.
FIG. 13 is a view for explaining another embodiment of the intermediate member according to the present invention.
FIG. 14 is a view for explaining another embodiment of the intermediate member according to the present invention.
FIG. 15 is a view for explaining another embodiment of the intermediate member according to the present invention.
FIG. 16 is a view for explaining another embodiment of the intermediate member according to the present invention.
FIG. 17 is a view for explaining another embodiment of the intermediate member according to the present invention.
FIG. 18 is a diagram for explaining the operation when the position of the intermediate member is changed.
FIG. 19 is a diagram for explaining the operation when the position of the intermediate member is changed.
FIG. 20 is a sequence diagram for explaining the operation at the time of ink filling.
FIG. 21 is a sequence diagram for explaining an operation at the time of ink filling.
FIG. 22 is a sequence diagram for explaining an operation at the time of ink filling.
FIG. 23 is a main part configuration diagram for explaining another embodiment of the present invention.
24 is a sequence diagram for explaining the operation of the embodiment shown in FIG. 23. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Recording device main body, 2 ... Printing mechanism part, 3 ... Paper, 4 ... Paper feed cassette, 5 ... Manual feed tray, 6 ... Paper discharge tray, 11 ... Main guide rod, 12 ... Sub guide rod, 13 ... Carriage, 14 Inkjet head, 15 ... Ink cartridge, 16 ... Recovery device, 20 ... Inkjet head section, 21 ... Liquid chamber substrate, 22 ... Electrode substrate, 23 ... Nozzle plate, 24 ... Power distribution member, 25, 26 ... Ink flow path member, 27 ... Filter, 28, 28a, 28b ... Ink flow path, 29 ... Power distribution member through hole, 31 ... Fluid resistance, 32 ... Pressurized liquid chamber, 33 ... Vibration plate, 34 ... Nozzle, 35 ... Filter chamber, 35a ... Inner wall of the filter chamber, 36 ... bubbles, 40, 41, 42, 43 ... intermediate member, 46 ... bubble trap space, 51 ... pressure member.

Claims (29)

  In an inkjet head that forms an image by ejecting ink in an ink liquid chamber from a nozzle, the ink chamber has a filter chamber in the middle of an ink flow path that supplies ink to the ink liquid chamber, and the upstream side of the filter chamber has the filter chamber. An intermediate member that divides the flow of ink to the filter chamber, and the intermediate member has a path length that reaches the filter from the upstream side through the filter chamber wall and a path length that reaches the filter from the upstream side through the intermediate member. An inkjet head characterized by having an equivalent shape.   The inkjet head according to claim 1, wherein the intermediate member is provided in contact with the filter.   The inkjet head according to claim 1, wherein the intermediate member divides the volume of the filter chamber into approximately equal parts.   The inkjet head according to claim 1, wherein a space between the intermediate member and the filter is widened toward the downstream.   The inkjet head according to any one of claims 1 to 4, wherein a hydrophilic treatment is applied to a surface of the intermediate member and an inner wall of the filter chamber.   6. The ink jet head according to claim 1, wherein a space surrounded by the intermediate member, the inner wall of the filter chamber, and the filter is symmetrical with respect to the ink filling direction.   The inkjet head according to claim 1, wherein the wettability of the intermediate member is substantially equal to the wettability of the inner wall of the filter chamber.   An ink jet head that forms an image by ejecting ink from an ink liquid chamber from a nozzle has a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber, and the pressure is applied from outside the filter chamber. An intermediate member for changing the filling volume of the filter chamber is provided, and when filling ink to supply ink to the ink liquid chamber through the filter in the filter chamber, the filling volume on the upstream side of the filter in the filter chamber is reduced by the intermediate member. An inkjet head characterized by that.   The inkjet head according to claim 8, wherein the intermediate member is a member that expands and contracts, and the intermediate member contacts the filter during expansion.   The inkjet head according to claim 9, wherein the intermediate member is formed with a reinforcing member at a contact portion with the filter.   The inkjet head according to claim 8, wherein the intermediate member is an elastic body formed on a wall surface of the filter chamber.   The inkjet head according to claim 8, wherein irregularities or grooves are formed on a surface of the intermediate member or an inner wall of the filter chamber. An inkjet head that forms an image by ejecting ink from an ink liquid chamber from a nozzle, has a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber, and a plurality of openings through which ink flows A plurality of intermediate members are provided in the direction of ink flow on the upstream side of the filter in the filter chamber. The upstream member has a larger opening diameter toward the upstream side , and the ink that forms a meniscus in the opening is once retained in the filter. An ink-jet head filled with ink.   The inkjet head according to claim 13, wherein the intermediate member has a plurality of openings, and an opening diameter of the openings is larger than an opening diameter of the filter.   The inkjet head according to claim 13, wherein the intermediate member is provided in proximity to the filter.   The inkjet head according to claim 13, wherein the intermediate member is provided in parallel to the filter. The inkjet head according to any one of claims 13 to 1 6, characterized in that said intermediate member is made of metal. An ink jet recording apparatus mounted with an ink jet head according to any one of claims 1 to 1 7.   An ink filling method for forming an image by ejecting ink in an ink liquid chamber from a nozzle, wherein the ink is filled in an ink jet head having a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber The filter chamber has an intermediate member for changing the filling volume of the filter chamber by pressure from the outside of the filter chamber, and starts the ink filling operation in a state where the intermediate member is expanded, An ink filling method for an ink jet head, wherein the ink filling operation is terminated after the intermediate member is contracted. 20. The ink filling method for an ink jet head according to claim 19 , wherein the intermediate member is a member that expands and contracts, and the intermediate member is brought into contact with the filter during expansion.   An ink filling method for forming an image by ejecting ink in an ink liquid chamber from a nozzle, wherein the ink is filled in an ink jet head having a filter chamber in the middle of an ink flow path for supplying ink to the ink liquid chamber And having an intermediate member having a plurality of openings on the upstream side of the filter chamber and having one side of the opening in close proximity to the filter, and at the start of ink filling, the downstream side of the filter is set to a negative pressure, Ink is supplied to the intermediate member from the other side of the opening to form a meniscus on the one side of the opening, and then the negative pressure is increased to bring the ink forming the meniscus into contact with the filter An ink filling method in an ink jet head, characterized in that:   In the filtering device for removing foreign matters in the liquid by passing a filter, an intermediate member for dividing the flow of ink to the filter chamber is provided upstream of the filter in the filter chamber in which the filter is disposed, and the intermediate The filtering device according to claim 1, wherein the member has a shape in which a path length reaching the filter through the filter inner wall from the upstream side is equal to a path length reaching the filter from the upstream side through the intermediate member.   In the filtering device that removes foreign matters in the liquid by passing the filter, an intermediate member that changes the filling volume of the filter chamber by pressure from outside the filter chamber on the upstream side of the filter in the filter chamber in which the filter is disposed. And a filtering device that reduces the filling volume of the filter chamber upstream of the filter chamber by the intermediate member when the filter chamber is filled with liquid. The intermediate member is expanded, a member that shrinks, filtering apparatus of claim 2 3, the intermediate member upon inflation, characterized in that in contact with the filter. Filtering device according to claim 2 3 wherein said that the intermediate member is an elastic body formed on the wall of the filter chamber.   In the filtering method for removing foreign substances in the liquid by passing the filter, an intermediate member for changing the volume of the filter chamber by pressure from outside the filter chamber is provided upstream of the filter in the filter chamber in which the filter is disposed. A filtering method, wherein filling of the liquid is started in a state where the volume of the filter chamber is reduced by the intermediate member, and then the volume of the filter chamber is increased. The intermediate member is expanded, a member that shrinks, filtering method according to claim 2 6, wherein the intermediate member contacting with the filter when inflated. Droplet discharge apparatus equipped with the ink jet head according to any one of claims 1 to 1 7. Image forming apparatus equipped with the ink jet head according to any one of claims 1 to 1 7.

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