Method of manufacturing a liquid ejecting head

A method for manufacturing a liquid ejecting head is provided. The liquid ejecting head has nozzle openings and ejects liquid supplied through a liquid supply passage from the nozzle openings. The manufacturing method includes: disposing a filtering member between a first supply member and a second supply member, the first supply member having one part of the liquid supply passage formed therein, the second supply member having the other part or another part of the liquid supply passage formed therein, the second supply member being disposed over one surface of the first supply member; and injecting a resin material over the one surface of the first supply member to cover a part of the second supply member for molding a fixation member and fixing the first supply member and the second supply member into a single-piece member as a result of the molding, wherein a convex is formed on a surface of the fixation member in the mold fixation of the first supply member and the second supply member, and a concave is formed in the surface of the fixation member in the mold fixation of the first supply member and the second supply member.

This application claims priority to Japanese Patent Application No. 2008-252,662, filed Sep. 30, 2008, the entirety of which is incorporated by reference herein.

BACKGROUND

1. Technical Field

The present invention generally relates to a liquid ejecting head that ejects liquid, a method for manufacturing a liquid ejecting head, and a liquid ejecting apparatus that is provided with a liquid ejecting head. More particularly, the invention relates to an ink-jet recording head that discharges ink as an example of various kinds of liquid, a method for manufacturing an ink-jet recording head, and an ink-jet recording apparatus that is provided with an ink-jet recording head.

2. Related Art

An ink-jet recording head, which is an example of various kinds of liquid ejecting heads, has the following configuration and ejects ink as follows. Ink is contained in ink cartridges, which are detachably attached to a cartridge case. When the ink cartridges are detachably attached to the cartridge case, ink-supply needles are detachably inserted into the ink cartridges. The ink cartridge is an example of a liquid container. The cartridge case is an example of a liquid supply member. The ink-supply needle is an example of a liquid supply inlet unit. An ink flow passage is formed inside and through each of the ink-supply needle and the supply member. The ink contained in the ink cartridge enters the ink-supply needle and then flows through the ink flow passage. The ink is supplied through the ink flow passage to an ink-ejecting head body. A pressure generating means such as a piezoelectric element or the like is provided in the head body. When the pressure generating means is driven, an ink-ejecting pressure is applied to the ink supplied to the head body. As a result, the ink jet recording head discharges ink from nozzles.

Air bubbles are often present in ink that is contained in an ink cartridge. In particular, air bubbles sometimes form in an ink cartridge at the time of the attachment or detachment thereof. If air bubbles that are present or formed in ink contained in an ink cartridge are entrained with the flow thereof at the time when the ink is supplied from the ink cartridge to the head body of the ink-jet recording head, such entrained air bubbles might reach the head body. As a result, the ink-discharging performance of the ink jet recording head could deteriorate. For example, missing dots, which is an ink-discharging problem, could occur due to the undesirable presence of air bubbles in ink retained inside the head body. In order to provide a technical solution to such a problem, some ink-jet recording heads of the related art have filters for trapping air bubbles, catching foreign objects and particles, and the like. Each of these filters is provided between the corresponding one of a plurality of ink-supply needles and a supply member. An example of such an ink jet recording head of the related art is disclosed in JP-A-2000-211130.

These filters and the supply member are fixed to each other by means of, for example, a heat-sealing technique or other adhesion/deposition technique. The ink-supply needles and the supply member are fixed to each other by means of, for example, an ultrasonic welding technique or other adhesion/deposition technique.

However, if the structure disclosed in JP-A-2000-211130 is adopted, it is necessary to fix the plurality of ink-supply needles to the supply member piece by piece. Since the plurality of ink-supply needles has to be fixed thereto individually, the manufacturing process thereof is not efficient, which increases production costs.

The problems identified above are not unique to an ink-jet recording head. That is, the same problems could also arise in various kinds of liquid ejecting heads.

SUMMARY

An advantage of some aspects of the invention is to provide a liquid ejecting head that makes it possible to reduce production costs. The invention further provides, as an advantage of some aspects thereof, a method for manufacturing such a liquid ejecting head and a liquid ejecting apparatus that is provided with such a liquid ejecting head.

In order to address the above-identified problems without any limitation thereto, a method for manufacturing a liquid ejecting head is provided. The liquid ejecting head has nozzle openings and ejects liquid supplied through a liquid supply passage from the nozzle openings. The manufacturing method according to a first aspect of the invention includes: disposing a filtering member between a first supply member and a second supply member, the first supply member having one part of the liquid supply passage formed therein, the second supply member having the other part or another part of the liquid supply passage formed therein, the second supply member being disposed over one surface of the first supply member; and injecting a resin material over the one surface of the first supply member to cover a part of the second supply member for molding a fixation member and fixing the first supply member and the second supply member into a single-piece member as a result of the molding, wherein a convex is formed on a surface of the fixation member in the mold fixation of the first supply member and the second supply member, and a concave is formed in the surface of the fixation member in the mold fixation of the first supply member and the second supply member.

With such a manufacturing method, it is possible to fix the first supply member and the second supply member to each other simultaneously (where either the first supply member or the second supply member may be made up of a plurality of member elements) by means of the molded fixation member through a single resin injection process in which a resin material is filled. Therefore, it is not necessary to individually fix the first supply member and the second supply member to each other one by one. Thus, it is possible to simplify a manufacturing process to reduce production costs. In addition, since convexes/concaves are formed on/in the surface of the fixation member, it is possible to determine the position of a liquid container or other members and the attachment height thereof with the use of the concaves and the convexes and then attach the liquid container or the like to the first supply member and the second supply member with high attachment precision.

Moreover, since the first supply member and the second supply member are fixed into a single-piece member as a result of the mold formation of the fixation member, it is not necessary to provide individual filter-attachment areas for attaching the filtering member to the first supply member and the second supply member. With such a structure, it is possible to increase the effective filtering area of the filtering member and shorten an interval between each two member elements of the first supply member or the second supply member that are arrayed adjacent to each other. For this reason, it is possible to reduce the size of a liquid ejecting head. Furthermore, since it is not necessary to decrease the area size of the filtering member in order to achieve the head-size reduction, dynamic pressure does not increase. Therefore, it is not necessary to increase a driving voltage, which is used for driving a pressure generation means such as a piezoelectric element, a heating element, or the like. Moreover, the fixation member prevents the formation of a gap between the first supply member and the second supply member. Therefore, the leakage of liquid through the gap would not occur.

In the method for manufacturing a liquid ejecting head according to the first aspect of the invention, it is preferable that the convex and the concave should be formed concurrently with the molding of the fixation member. With such a preferred manufacturing method, since the convex and the concave are formed in the same process as the formation of the fixation member, it is possible to make a series of manufacturing processes simpler in comparison with a case where the convex and the concave are formed in a separate formation process, that is, not concurrently with the molding of the fixation member.

In the method for manufacturing a liquid ejecting head according to the first aspect of the invention, it is preferable that the convex and the concave should be formed after the molding of the fixation member. With such a preferred manufacturing method, it is possible to form the convex at a desired position on the surface of the molded fixation member and the concave at a desired position in the surface of the molded fixation member after the fixation-member molding process.

In the method for manufacturing a liquid ejecting head according to the first aspect of the invention, it is preferable that the fixation member should be molded in such a manner that the liquid supply passage only penetrates through the fixation member. With such a preferred manufacturing method, the fluidity of a resin material improves. The resin material flows without being obstructed and is filled throughout the entire area where the fixation member is to be formed. Thus, it is possible to form the fixation member that has adequate strength in a reliable manner.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

With reference to the accompanying drawings, exemplary embodiments of the present invention will now be explained in detail.

First Embodiment

FIG. 1is a perspective view that schematically illustrates an example of the configuration of an ink jet recording apparatus, which is an example of various kinds of liquid ejecting apparatuses according to a first embodiment of the invention. As illustrated inFIG. 1, an ink-jet recording apparatus10according to the present embodiment of the invention is provided with an ink jet recording head11that discharges ink drops. The ink jet recording head11is an example of various kinds of liquid ejecting heads according to an aspect of the invention. The ink jet recording apparatus10is further provided with a carriage12to which the ink jet recording head11is fixed. Ink cartridges13, each of which constitutes an example of a liquid container according to an aspect of the invention, are detachably attached to the ink-jet recording head11. Each of these ink cartridges13contains ink that has the corresponding one of a set of ink colors, for example, black (B) [K], light black (LB), cyan (C), magenta (M), and yellow (Y). In the following description, the ink jet recording head11may be simply referred to as “recording head”11.

The carriage12on which the recording head11is mounted is configured to move freely in the axial direction of a carriage shaft15, which is fixed to an apparatus body chassis14. As the driving force of a driving motor16is transmitted to the carriage12through the rotation of a plurality of gears and a timing belt17, the carriage12travels along the carriage shaft15. Note that the plurality of gears is not illustrated in the drawing. A platen18is provided in the apparatus body chassis14along the carriage shaft15. A paper-feeding device or the like, which is not illustrated in the drawing, feeds a recording target medium S such as a sheet of printing paper. The recording target medium S is transported on the platen18.

A capping device20is provided at a position corresponding to the home position of the carriage12. The home position of the carriage12is located at one end area of the carriage shaft15. The capping device20provided in the proximity of the one end area of the carriage shaft15includes a capping member19. The capping member19seals the nozzle surface of the recording head11. The capping member19prevents any ink remaining on the nozzle surface of the recording head11, which has a number of nozzle holes/orifices formed therein, from becoming dried. In addition to the nozzle-surface sealing function described above, the capping member19also functions as an ink catcher that catches ink drops at the time of flushing operation.

In the following description, the configuration of the recording head11according to the present embodiment of the invention is explained.FIG. 2is an exploded perspective view that schematically illustrates an example of the configuration of the ink-jet recording head11according to the present embodiment of the invention.

As illustrated inFIG. 2, the recording head11includes an ink-supplying member30, an ink-ejecting head body220, and a cover head240. An example of the ink-supplying member30is a cartridge case to which the ink cartridges13are detachably attached. The head body220is fixed to a surface of the ink-supplying member30that is opposite to the cartridge-side surface thereof over which the ink cartridges13are attached. The cover head240is provided at the liquid-ejecting surface side of the head body220.

First of all, the structure of the supply member30is explained in detail below.FIG. 3is a top view that schematically illustrates an example of the structure of a supply member according to the present embodiment of the invention.FIG. 4is a sectional view taken along the line IV-IV ofFIG. 3.

As illustrated inFIG. 4, the supply member30includes a first supply member, a second supply member, a filtering member, and a fixation member. The filtering member is sandwiched between the first supply member and the second supply member. The second supply member is disposed over one surface of the first supply member. The first supply member and the second supply member are fixed to each other by means of the fixation member with the filtering member being sandwiched therebetween. A supply member main body31, which is provided at a relatively downstream position when viewed along a fluid channel, corresponds to either one of the first supply member and the second supply member. Ink-supply needles32, each of which is provided at a relatively upstream position when viewed from the downstream supply member main body31, correspond to the other of the first supply member and the second supply member. It is assumed in the present embodiment of the invention that the supply member main body31is the first supply member.

The supply member30includes a supply unit formation portion35to which each of a plurality of liquid containers such as the ink cartridges13is detachably attached over one surface thereof. Though it is explained above that the ink cartridges13are directly attached to the supply unit formation portion35, needless to say, the mode of the supplying of liquid is not limited to the above example. As a modification example, liquid such as ink may be supplied from a liquid container to the supply unit formation portion35indirectly through a tube.

The supply member main body31has liquid supply passages36through which ink supplied from the ink cartridges13flows toward the head body220. The liquid supply passages36are formed at relatively downstream positions when viewed from filters33, which will be explained later. One end of the liquid supply passage36, which is formed as a through hole inside the supply member main body31, opens on one surface of the supply member main body31, or more specifically, the surface of the supply member main body31over which the ink-supply needle32is provided. The other end of the liquid supply passage36opens toward the head body220. The plurality of liquid supply passages36are arrayed to form two lines that extend parallel to each other in the direction of the long sides of the supply member main body31. The pairs of liquid supply passages36are formed as independent passages that are respectively dedicated to the ink cartridges13of the corresponding ink colors.

A peripheral area formed around the opening of each liquid supply passage36at the one-surface side of the supply member main body31functions as a filter-sandwiching area portion37. Each filter33is sandwiched between the filter-sandwiching area portion37of the supply member main body31and the opposite area portion of the corresponding ink-supply needle32. The peripheral area formed around the opening of the liquid supply passage36is a surrounding area portion formed in the vicinity of the widened opening thereof, and thus, in the vicinity of an opposite filtering chamber41. It is preferable to form the peripheral area as close as possible to the opening for saving space.

A bank portion43is formed as a part of the supply member main body31on the one surface thereof outside an area at which a fixation portion34is to be formed. The bank portion43is formed to surround the fixation portion formation area. A stepped surface portion45is formed as a level difference in the top surface of the bank portion43. The step portion45is made up of an upper step portion45a, which is a raised portion, and a lower step portion45b. The upper step portion45ais formed as the outer part of the step portion45. The lower step portion45ais formed as the inner part of the step portion45. The upper surface of the lower step portion45bfunctions as a metal mold placement surface44. A metal mold (i.e., mold form or formwork) is placed on the metal mold placement surface44in the process of manufacturing the fixation portion34. A more detailed explanation of the molding of the fixation portion34will be given later.

Except for the filter-sandwiching area portion37, the inner surface area of the supply member main body31that is embanked by the surrounding bank portion43is formed as a substantially flat surface. Since the inner area is formed as a flat surface, a fluid resin material flows smoothly thereon without being trapped, blocked, or obstructed in any other way due to the presence of an uneven surface at the time when the resin material is injected for the formation of the fixation portion34. Therefore, it is ensured that the resin material is filled inside the bank portion43without leaving a gap.

The ink-supply needle32, which is fixed at the one-surface side of the supply member main body31, has a tip portion46. The ink-supply needle32further has a flared base portion47. The width (i.e., diameter) of the flared base portion47increases toward the bottom thereof. A needle-side liquid supply passage40is formed inside the ink-supply needle32. The needle-side liquid supply passage40is in communication with an ink inlet hole51that is formed through the tip portion46. The needle-side liquid supply passage40is in communication with liquid supply passage36with the filter33being interposed therebetween. The needle-side liquid supply passage40includes the filter chamber41. The filter chamber41is an inner wide space whose diameter increases toward the liquid supply passage36. The filter-side opening of the filter chamber41functions as a liquid supply port Ink supplied from the ink cartridge13flows through the liquid supply port to be further supplied to the supply member main body31.

A filter-sandwiching area portion42is formed as the bottom surface of the ink-supply needle32. The filter-sandwiching area portion42of the ink-supply needle32is provided opposite to the filter-sandwiching area portion37of the supply member main body31. The filter33is sandwiched between the filter-sandwiching area portions37and42.

The filter33is formed as, for example, a sheet of metal that is woven to have a fine mesh structure. The filter33is attached to the supply member main body31by means of, for example, a heat sealing technique or other adhesion/deposition technique and then sandwiched between the supply member main body31and the ink-supply needle32. In the structure of the supply member30according to the present embodiment of the invention, the filter33has a size that fits in a filter-sandwiching area formed by the supply member main body31and the ink-supply needle32. The filter33may be attached to the ink-supply needle32.

The fixation portion34is provided at the one-surface side of the supply member main body31. The fixation portion34covers a part of the ink-supply needle32, thereby fixing the supply member main body31and the ink-supply needle32to each other. The fixation portion34is made of resin. The fixation portion34is formed by means of an integral molding method. The meaning of “the fixation portion34covers a part of the ink-supply needle32” is as follows. The fixation portion34covers at least a region near the perimeter of the filter-sandwiching area at which the filter33is sandwiched between the supply member main body31and the ink-supply needle32. In addition, the fixation portion34is provided in such a manner that at least the ink inlet hole51of the ink-supply needle32is exposed. Since the fixation portion34covers at least a region near the perimeter of the filter-sandwiching area, it is possible to prevent the leakage of ink from the main-body-side liquid supply passage36and the needle-side liquid supply passage40to the outside. Moreover, since the fixation portion34does not cover the ink inlet hole51, the fixation portion34does not obstruct the supply of ink from the ink cartridge13to the ink-supply needle32.

In the structure of the supply member30according to the present embodiment of the invention, the fixation portion34covers a region near the perimeter of the filter-sandwiching area portion37of the supply member main body31and further covers the flared base portion47of the ink-supply needle32. In addition, the fixation portion34is formed in such a manner that a needle body including the tip portion46of each ink-supply needle32protrudes from the covered base portion47thereof without being covered by the fixation portion34. Since the fixation portion34is provided as explained above, the supply member main body31and the ink-supply needles32are fixed to each other. In addition, it is possible to prevent the leakage of ink from any of the main-body liquid supply passages36and the needle-side liquid supply passages40to the outside.

As a non-limiting example of a concave according to an aspect of the invention, position determination concave portions48are formed in the surface of the fixation portion34. In addition, as a non-limiting example of a convex according to an aspect of the invention, height adjustment convex portions49are formed on the surface of the fixation portion34. More specifically, the position determination concave portion48is a recess that is formed in the surface of the fixation portion34. Two position determination concave portions48are formed at a center area between one of each pair of the ink-supply needles32arrayed next to each other when viewed along the short sides of the supply member main body31and the other thereof. The height adjustment convex portion49is a small projection that is formed on the surface of the fixation portion34. Each height adjustment convex portion49is provided at an outer position opposite to inner positions where two position determination concave portions48are formed with the ink-supply needle32being provided therebetween. Two height adjustment convex portions49are formed for each pair of the ink-supply needles32. The height of one of these two height adjustment convex portions49measured from the surface of the fixation portion34is the same as that of the other.

The position determination concave portions48and the height adjustment convex portions49are used for determining the plan position and the height of the ink cartridge13or the like when the ink cartridge13is detachably attached to the supply unit formation portion35.FIG. 5is a sectional view that schematically illustrates an example of the structure of a supply member according to the present embodiment of the invention to which the ink cartridge13is attached. As illustrated inFIG. 5, needle insertion openings90are formed through the needle-side surface of the ink cartridge13. When the ink cartridge13is attached to the supply member30with the needle-side surface facing downward, the tip portions46of the ink-supply needles32are inserted through the openings90, respectively. In such an attachment state, the ink inlet holes51formed through the tip portions46are in communication with the inner ink-containing space of the ink cartridge13. More specifically, the tip portions46of the ink-supply needles32are inserted through O-shaped rings91, which are formed at the circumference of the openings90of the ink cartridge13. Since the tip portions46fit into the O-shaped rings91, it is possible to prevent ink from leaking through the openings90.

Position determination pins92are formed on the bottom surface of the ink cartridge13. The position determination pins92are inserted in the position determination concave portions48. The insertion of the position determination pins92into the position determination concave portions48makes it possible to attach the ink cartridge13to the supply unit formation portion35at a predetermined attachment position. In addition, the height adjustment convex portions49are in contact with the bottom surface of the ink cartridge13. That is, when the ink cartridge13is attached to the supply member30, the ink cartridge13is pressed toward the fixation portion34until the bottom surface thereof is brought into contact with the height adjustment convex portions49. By this means, it is possible to attach the ink cartridge13to the supply member30at a predetermined attachment height, that is, while leaving a predetermined distance from the surface of the fixation portion34.

The concaves formed in the fixation portion34are not limited to be used for determining the attachment position of the ink cartridge13. The convexes formed on the fixation portion34are not limited to be used for determining the attachment height of the ink cartridge13. For example, when the ink cartridge13is not directly attached to the supply member30but provided at a distant position from which ink is supplied to the liquid supply passage40through a tube, the concaves may be used for determining the attachment position of a relay supply member that feeds ink coming through the tube to the ink-supply needle32. In such a case, the convexes can be used for determining the attachment height of the relay supply member. The size of the convexes and concaves, the number thereof, the position thereof, and the depth thereof are not limitedly specified herein. Accordingly, the size, the number, the position, and the depth thereof may be arbitrarily determined depending on a member that is to be attached to the supply unit formation portion35.

As explained above, the supply member main body31and the ink-supply needles32with the filters33being sandwiched therebetween are fixed to each other by means of the fixation portion34, which is formed by integral molding. The plurality of ink-supply needles32is fixed to the supply member main body31in a single fixation process at the same time. That is, it is not necessary to fix ink-supply needles to a supply member main body piece by piece. Therefore, it is possible to reduce production costs.

In addition, since the position determination concave portions48are formed in the surface of the fixation portion34, it is possible to determine the position of the ink cartridge13or the like relative to the position of the supply unit formation portion35accurately and attach the ink cartridge13to the supply member30with greater positional precision. Moreover, since the height adjustment convex portions49are formed on the surface of the fixation portion34, it is possible to determine the attachment height of the ink cartridge13with greater precision.

Furthermore, in contrast to a related-art structure according to which it is necessary to provide welding/attachment areas in a supply member main body so that ink-supply needles and filters can be individually welded/attached thereat, these welding/attachment areas are not necessary in the structure of the recording head11according to the present embodiment of the invention because the supply member main body31and the ink-supply needles32with the filters33being sandwiched therebetween are fixed to each other by means of the fixation portion34. With such a structure, an interval between each two ink-supply needles32arrayed adjacent to each other is shortened, which makes it possible to reduce the size of the recording head11. Moreover, since the reduction in the size of the recording head11can be achieved by reducing the array pitch of the ink-supply needles32, it is not necessary to decrease the area size of each filter in order to achieve the head-size reduction. If the area size of each filter is decreased, dynamic pressure increases. Therefore, it is necessary to increase a driving voltage, which is used for driving a pressure generation means such as a piezoelectric element, a heating element, or the like. In contrast, in the present embodiment of the invention, since it is not necessary to decrease the area size of each filter in order to achieve the head-size reduction, dynamic pressure does not increase. Therefore, it is not necessary to increase a driving voltage.

In a related-art structure, a supply member main body and ink-supply needles are fixed to each other by welding. In such a method, there is a possibility that a gap is formed therebetween. If the gap exists, ink might leak through the gap. In contrast, since the supply member main body31and the ink-supply needles32are fixed to each other by means of the fixation portion34in the structure of the recording head11according to the present embodiment of the invention, the risk of the formation of a gap therebetween is substantially smaller, which makes it possible to avoid the leakage of ink through the gap. Even if any gap were formed therebetween, though it is substantially less likely to occur, the leakage of ink through the gap would not occur because the fixation portion34covers the gap.

Next, a method for manufacturing the ink jet recording head11, especially, a method for manufacturing the supply member30, is explained in detail below. Each ofFIGS. 6 and 7is a sectional view that schematically illustrates an example of a method for manufacturing a supply member according to an exemplary embodiment of the invention.

As a first step, as illustrated inFIG. 6, the filters33are placed on the filter-sandwiching area portion37of the supply member main body31. The circumferential area of each filter33is attached to the filter-sandwiching area portion37. Next, the ink-supply needles32are placed on the filters33so that the filters33are sandwiched between the filter-sandwiching area portion37of the supply member main body31and the filter-sandwiching area portion42of the ink-supply needles32. With the filters33being sandwiched therebetween, a metal mold200is placed on the metal mold placement surface44of the bank portion43.

As its name indicates, the metal mold200is made of metal. The metal mold200has a shape that fits with the inner surface of the upper step portion45aof the bank portion43. When the metal mold200is placed on the metal mold placement surface44of the bank portion43, the metal mold200seals a space inside the bank portion43. That is, the supply member main body31, the bank portion43, and the metal mold200create an inner space204. The metal mold200has through holes202. The ink-supply needles32are inserted through the through holes202when the metal mold200is placed on the metal mold placement surface44. A needle body including the tip portion46of each ink-supply needle32protrudes through the through hole202of the metal mold200, whereas the flared base portion47thereof lies under the lower surface of the metal mold200, that is, inside the inner space204. A resin injection gate201is formed through the metal mold200. A fluid resin material is injected through the gate201. A mold form or a formwork made of a material other than metal may be used as a substitute for the metal mold200as long as the mold form seals the inner space204.

Convex portions205are formed on the lower surface of the metal mold200. The convex portions205of the metal mold200are formed at positions corresponding to positions where the position determination concave portions48of the fixation portion34are to be formed. In addition, concave portions206are formed in the lower surface of the metal mold200. The concave portions206of the metal mold200are formed at positions corresponding to positions where the height adjustment convex portions49of the fixation portion34are to be formed.

As illustrated inFIG. 7, a fluid resin material is injected through the gate201into the inner space204so as to form the fixation portion34by integral molding, thereby manufacturing the supply member30. Specifically, a molten resin material is filled into the inner space204through the gate201of the metal mold200to be molded into the fixation portion34. As a result, the fixation portion34covers the flared base portion47of the ink-supply needle32and fixes the ink-supply needles32to the supply member main body31with the filters33being sandwiched therebetween to form a single-piece integrated member.

Since the concave portions206are formed in the lower surface of the metal mold200, some resin material flows into the concave portions206of the metal mold200in the resin filling process and then hardens into the height adjustment convex portions49, the formation of which is carried out concurrently with the formation of the fixation portion34. In addition, since the convex portions205are formed on the lower surface of the metal mold200, the position determination concave portions48are formed at the same time as the formation of the fixation portion34. Since the position determination concave portions48and the height adjustment convex portions49are formed in the same process as the formation of the fixation portion34, it is possible to make a series of manufacturing processes simpler in comparison with a case where the position determination concave portions48and/or the height adjustment convex portions49are formed in a separate formation process.

As explained earlier, the inner surface area of the supply member main body31that is embanked by the surrounding bank portion43is formed as a substantially flat surface except for the filter-sandwiching area portion37. In addition, a resin material is injected into the inner space204with a needle body including the tip portion46of each ink-supply needle32protruding through the through hole202of the metal mold200. Therefore, it is possible to form the fixation portion34in such a manner that the ink-supply needles32only penetrate through the fixation portion34. The meaning of “the ink-supply needles32only penetrate through the fixation portion34” is that no member/portion that penetrates through the fixation portion34is formed as a part of the supply member main body31. Though the supply member main body31may have some convex portion that is low enough so as not to penetrate through the fixation portion34, it is preferable that the inner surface area of the supply member main body31should be formed as a flat surface without a surface level difference except for the filter-sandwiching area portion37.

Since the fixation portion34is formed in such a manner that the ink-supply needles32only penetrate through the fixation portion34, it is possible to fill a resin material that is injected through the gate201into the space204without a filling failure. A more detailed explanation of such an advantage is given below with reference toFIG. 8.

FIGS. 8A and 8Bare a set of essential-part cross section views that schematically illustrates an example of the fluidity of a resin material that flows on a supply member. For the purpose of explanation, it is assumed here that a height adjustment convex portion49A is provided on the supply member main body31as illustrated inFIG. 8A. The height adjustment convex portion49A is formed to penetrate through the fixation portion34when a resin material is filled into the space204so that the tip portion of the height adjustment convex portion49A protruding through the fixation portion34is in contact with the ink cartridge13. If such a structure is adopted, the flow of the resin material (fixation portion34) injected through the gate201of the metal mold200is obstructed by the height adjustment convex portion49A. For this reason, there is a risk that the resin material is not filled sufficiently at, for example, a space between the bank portion43and the height adjustment convex portion49A. Such poor resin filling might result in the formation of a fragile fixation portion34that lacks strength.

In contrast, as illustrated inFIG. 8B, no member/portion that penetrates through the fixation portion34is formed as a part of the supply member main body31according to the present embodiment of the invention. That is, the inner surface area of the supply member main body31is formed as a flat surface without a surface level difference except for the filter-sandwiching area portion37. Therefore, the resin material (fixation portion34) injected through the gate201of the metal mold200flows smoothly without being obstructed to reach the inner surface of the bank portion43. Thus, it is possible to fill a resin material into the space204without a filling failure.

In the foregoing description of the present embodiment of the invention, the ink-supply needle32is mentioned as an example of a member that penetrates through the fixation portion34. However, the scope of the invention is not limited to such an exemplary structure. The structure can be modified in various ways with liquid supply passages (or a member that constitutes liquid supply passages) only penetrating through the fixation portion34.

Since the supply member30is manufactured as explained above, it is possible to fix the plurality of ink-supply needles32to the supply member main body31simultaneously through a single resin injection process in which a resin material is filled into the space204. Therefore, it is not necessary to weld the plurality of ink-supply needles32to the supply member main body31one by one. Thus, it is possible to simplify a manufacturing process to reduce production costs.

Since the metal mold200is placed on the metal mold placement surface44of the bank portion43, it is possible to prevent a resin material injected into the space204from flowing over the bank portion43to leak out of the space204. Specifically, if the upper surface of a bank portion were formed as a flat surface on which the metal mold200is placed, a resin material would flow over the flat upper surface when it leaks out of the space204. In contrast, with the structure explained above in which the metal mold200is placed on the metal mold placement surface44of the bank portion43, a resin material is less likely to leak out because it has to surmount the upper step portion45abefore leakage. Therefore, the injection pressure of a resin material can be increased without causing the leakage thereof, thereby making it possible to fill the resin material into and throughout the entire space204without leaving a filling gap. By this means, it is possible to form the fixation portion34that fixes the ink-supply needles32to the supply member main body31securely to make up a single-piece integrated member.

Moreover, since the space204is formed as a result of placing the metal mold200on the metal mold placement surface44, the metal mold200absorbs the heat of a resin material that is filled in the space204. Therefore, the deformation of the ink-supply needles32due to the heat of the resin material does not occur.

Furthermore, the filters33are pre-attached to the supply member main body31before being sandwiched between the supply member main body31and the ink-supply needles32. Therefore, the positional displacement of the filters33does not occur when fixed by the fixation portion34. If the position of the filter33were shifted, the needle-side liquid supply passage40would be in communication with the main-body liquid supply passage36without the filter33being interposed therebetween at a correct position. Accordingly, in such a case, impurities would flow into the main-body liquid supply passage36without being trapped by the filter33. This does not occur because the filters33are pre-welded thereto.

The head body220is provided in communication with the other end of each liquid supply passage36of the supply member30that is opposite to the one end thereof that is in communication with the corresponding ink-supply needle32. Next, the structure of the head body220is explained below.FIG. 9is an exploded perspective view that schematically illustrates an example of the configuration of a head body according to the present embodiment of the invention.FIG. 10is a sectional view that schematically illustrates an example of the structure of the head body illustrated inFIG. 9.

A fluid channel formation substrate60that constitutes a part of the head body220is made of silicon single crystal. As illustrated in these drawings, an elastic membrane50, which is made of silicon dioxide, is formed on one surface of the fluid channel formation substrate60. A plurality of pressure generation chambers62is formed in the fluid channel formation substrate60. A plurality of partition walls demarcates the pressure generation compartments62. Two lines of the pressure generation chambers62, viewed in the width direction of the fluid channel formation substrate60, are formed therein. By employing an anisotropic etching technique, the pressure generation chambers62are formed from the opposite side of the fluid channel formation substrate60. A communicating portion63is formed at an area outside each array of pressure generation chambers62, viewed in the longitudinal direction thereof. Each of the communicating portions63is in communication with a reservoir portion81that is provided in a reservoir formation substrate80that will be explained later. Being in communication with each other, the communicating portion63and the reservoir portion81constitute a reservoir100, which serves as a common ink chamber/compartment for each of the pressure generation chambers62. The communicating portion63is in communication with the “longitudinal-direction-one-end-portion” of each of the pressure generation chambers62via an ink supply passage64. That is, in the structure of the head body220according to the present embodiment of the invention, the pressure generation chamber62, the communicating portion63, and the ink supply passage64constitute a fluid channel (i.e., liquid flow passage) formed in the fluid channel formation substrate60.

A nozzle plate70is bonded to the opening surface of the fluid channel formation substrate60by means of an adhesive400. A plurality of nozzle holes71is bored through the nozzle plate70. A plurality of nozzle plates70is provided so as to correspond to a plurality of head bodies220. Each nozzle plate70has an area size that is slightly larger than an exposure opening area241of the cover head240, which will be explained in detail later. The nozzle plates70are fixed to the cover head240with the use of an adhesive or the like at overlapping areas. Each nozzle opening71of the nozzle plate70is in communication with one end of the corresponding pressure generation chamber62that is opposite to the other end that is in communication with the ink supply passage64. In the present embodiment of the invention, two lines of the pressure generation chambers62are formed next and parallel to each other in the fluid channel formation substrate60. Accordingly, two nozzle lines71A, which are a pair of lines of the nozzle openings71formed next and parallel to each other, are provided in each of the plurality of head bodies220. In addition, in the present embodiment of the invention, the surface at which these nozzle holes71of the nozzle plate70open to the outside constitutes a liquid-ejecting surface thereof. The nozzle plate70is made of, for example, a silicon single crystal substrate, metal such as stainless steel (SUS), or the like.

An elastic membrane50is formed on the other surface of the fluid channel formation substrate60that is opposite to the opening surface thereof. Piezoelectric elements300are formed on the elastic membrane50. The piezoelectric element300includes a lower electrode film that is made of metal, a piezoelectric substance layer that is made of a piezoelectric material such as lead zirconate titanate (PZT) or the like, and an upper electrode film that is made of metal. The lower electrode film, the piezoelectric substance layer, and the upper electrode film are laminated in the order of appearance herein to make up the piezoelectric element300.

The reservoir formation substrate80having the reservoir portion81that constitutes at least a part of the reservoir100is bonded to the fluid channel formation substrate60over which the piezoelectric elements300are formed. In the present embodiment of the invention, the reservoir portion81is formed through the reservoir formation substrate80in a thickness direction thereof while extending in the width direction of the pressure generation chambers62. As explained earlier, the reservoir portion81is in communication with the communicating portion63of the fluid channel formation substrate60in such a manner that the reservoir portion81and the communicating portion63constitute the reservoir100, which serves as a common ink chamber/compartment for each of the pressure generation chambers62.

A piezoelectric-element housing portion82is provided at an area opposite to each of the piezoelectric elements300of the reservoir formation substrate80. The piezoelectric-element housing portion82has some space that is wide enough so as not to obstruct the motion of the piezoelectric element300.

A driving circuit110is provided on the reservoir formation substrate80. The driving circuit110drives each piezoelectric element300. The driving circuit110is, for example, a semiconductor integrated circuit (IC). Each terminal of the driving circuit110is connected to a line that is drawn out from an individual electrode of each piezoelectric element300via a bonding wire or the like, which is not shown in the drawing. The terminals of the driving circuit110are connected to an external device via an external wiring111made of a flexible printed cable (FPC) or the like. Through the external wiring111, the driving circuit110receives various kinds of signals including but not limited to a printing signal from the external device connected thereto.

A compliance substrate140is bonded to the reservoir formation substrate80. An ink induction port144is formed through the compliance substrate140in a thickness direction thereof. The ink induction port144is formed at some part of a reservoir area of the compliance substrate140, which is an area opposite to the reservoir100. The ink induction port144is provided to supply ink to the reservoir100. The remaining part of the reservoir area of the compliance substrate140opposite to the reservoir100, that is, the part of the reservoir area where the ink induction port144is not formed, is formed as a flexible portion143having a relatively smaller thickness. The flexible portion143seals the reservoir100. The flexible portion143gives compliance inside the reservoir100.

A head case230is provided on the compliance substrate140.

An ink supply communicating passage231is formed through the head case230. One end of the ink supply communicating passage231is in communication with the liquid supply passage36of the supply member30. The other end of the ink supply communicating passage231is in communication with the ink induction port144. Ink supplied from the supply member30flows through the ink supply communicating passage231to be supplied to the ink induction port144. A gutter portion232is formed in the head case230at an area opposite to the flexible portion143of the compliance substrate140. With such a structure, the flexible portion43can become deflected. The head case230has a driving circuit encasing portion233, which is formed by boring a hollow cavity through the head case230in a thickness direction thereof, at an area opposite to the driving circuit110provided on the reservoir formation substrate80. The external wiring111passes through the driving circuit encasing portion233to be electrically connected to the driving circuit110.

Each of members/components that make up the head body220described above is provided with pin insertion holes234, which are formed at two of four corners thereof. The pin insertion holes234are holes through which pins are to be inserted for the positional determination of these members/components at the time of assembly thereof. These members/components are bonded together while determining the relative positions thereof by inserting pins through the pin insertion holes234. As a result, the head body220is assembled as a single-piece integrated unit.

As illustrated inFIG. 2, the cover head240is attached to five head bodies220, which are mounted to the supply member30with the same number of head cases230being interposed therebetween. The cover head240has an open-topped-box-like shape and covers the periphery of each of the liquid ejecting surfaces of the head bodies220. The cover head240has a function of determining the relative positions of these head bodies220. The cover head240has the exposure opening areas241and an attachment portion242. The nozzle holes71of the nozzle plates70are exposed through the exposure opening areas241. The attachment portion242demarcates each exposure opening area241. The attachment portion242is attached to the liquid ejecting surfaces of the head bodies220at least at two end areas opposite to each other. The nozzle lines71A of the nozzle openings71formed next and parallel to each other are formed between the two end areas.

In the present embodiment of the invention, the attachment portion242is made up of a frame portion243and beam portions244. The frame portion243is a peripheral frame that encloses the liquid ejecting surfaces of the head bodies220. Each of the beam portions244extends between two head bodies220mounted next to each other in such a manner that these beam portions244divide an inner area into the exposure opening areas241. The frame portion243and the beam portions244are attached to the liquid ejecting surfaces of the head bodies220. In other words, the frame portion243and the beam portions244are attached to the surfaces of the nozzle plates70.

The cover head240further has a sidewall portion245. The sidewall portion245is formed by bending a cover head material in such a manner that each part thereof extends from the peripheral edge of the liquid ejecting surface along the side of the head bodies220.

As explained above, the attachment portion242of the cover head240is attached to the liquid ejecting surfaces of the head bodies220. With such a structure, it is possible to make a difference in level between the liquid ejecting surfaces of the head bodies220and the cover head240relatively small. Since the level difference therebetween is small, it is further possible to prevent any ink from remaining on the liquid ejecting surfaces thereof when wiping operation, suction operation, or the like, is performed. In addition, since each of the beam portions244of the cover head240covers a gap between two head bodies220fixed adjacent to each other, it is possible to prevent ink from infiltrating through the gap between these two adjacent head bodies220. For this reason, the components of the head body220such as the piezoelectric elements300, the driving circuit110, and the like are protected from otherwise possible degradation or damage due to ink infiltration. Moreover, since the liquid ejecting surfaces of the head bodies220are bonded to the cover head240by means of an adhesive with no gap left therebetween, it is possible to prevent a recording target medium S such as a sheet paper from entering therebetween, that is, getting pinched or jammed therebetween. Thus, the deformation of the cover head240and paper jam malfunction do not occur. In addition, it is possible to prevent the overflow/infiltration of ink over/into the side surfaces of the head bodies220securely because the sidewall portion245of the cover head240completely covers the outer edges of the head bodies220. Moreover, since the cover head240has the attachment portion242that is bonded to the liquid ejecting surfaces of the head bodies220, when bonding is performed, it is possible to determine the position of each pair of the nozzle lines71A of the plurality of head bodies220with high positional precision with respect to the cover head240.

An example of the material of the cover head240is a metal such as stainless steel. The cover head240may be manufactured by press-working a metal plate, or alternatively, by metal-forming thereof. The cover head240can be grounded if an electrically conductive metal material is employed. The method of the attachment of the cover head240to the nozzle plates70is not limited to the bonding explained above. When the cover head240is bonded to the nozzle plates70, for example, a thermosetting epoxy adhesive, an ultraviolet hardening-type (UV cure) adhesive, or the like may be used.

The ink jet recording head11according to the present embodiment of the invention having the structure explained above operates as follows. Ink supplied from the ink cartridge13enters the needle-side liquid supply passage40. Then, the ink flows through the main-body-side liquid supply passage36, the ink supply communicating passage231, and the ink induction port144in the order of appearance herein. The inner fluid channel structure from the reservoir100to the nozzle orifices71is filled with the supplied ink. Thereafter, in accordance with a recording signal sent from the driving circuit110, a voltage is applied to each piezoelectric element300provided for the corresponding pressure generation chamber62so as to deflect and deform the elastic membrane50and the piezoelectric element300. By this means, the inner pressure of each of the pressure generation chambers62is raised; and as a result thereof, an ink drop is discharged from the corresponding nozzle hole71.

Variant Embodiments

Although an exemplary embodiment of the invention is explained above, the scope of the invention as well as the basic configuration thereof is in no case limited to the specific embodiment/examples described above.

For example, the structures of the first supply member and the second supply member are not limited to those of the exemplary embodiment described above. It is assumed in the foregoing exemplary embodiment of the invention that the supply member main body31and the ink-supply needles32correspond to the first supply member and the second supply member, respectively. However, the correspondence may be reversed. That is, the first supply member may be the ink-supply needle32, which means that the second supply member is the supply member main body31. In addition, though it is assumed in the foregoing exemplary embodiment of the invention that the entire supply member main body31constitutes the first supply member, the first supply member may be embodied as a part of the supply member main body31. Specifically, the supply member main body31may be split into a filter-side (33) member and a head-body-side (220) member, with the first supply member being embodied as the filter-side (33) member. The filter-side (33) member is fixed to the ink-supply needles32to make up an integrated member. Then, the head-body-side (220) member is fixed to the integrated member to make up the supply member30.

In the foregoing description of an exemplary embodiment of the invention, it is explained that the ink cartridge13, which is an example of a liquid container, is detachably attached to the supply member30. However, the structure explained above can be modified in various ways. For example, an ink tank or the like may be provided not on the recording head11but at a remote position away from the recording head11as a liquid container. The liquid container may be connected through a liquid conduit such as a tube or the like to the recording head11. That is, although the ink-supply needle32is taken as an example of a liquid supply inlet unit in the foregoing description of an exemplary embodiment of the invention, the liquid supply inlet unit is not limited to a needle member.

In the foregoing description of an exemplary embodiment of the invention, it is explained that each head body220is provided for more than one liquid supply passage36. As a modification thereof, more than one head body may be provided for each ink color. For example, each liquid supply passage36may be in communication with a head body. Each liquid supply passage36may be in communication with the corresponding one of a plurality of parallel lines of nozzle holes formed in a head body. Needless to say, it is not always necessary for each liquid supply passage36to be in communication with the corresponding one of a plurality of parallel lines of nozzle holes formed in a head body. Each liquid supply passage36may be in communication with a plurality of parallel lines of nozzle holes formed in a head body. Each line of nozzle holes may be divided into two groups. In such a modified configuration, each liquid supply passage36is in communication with the corresponding group of nozzle holes formed in a head body. That is, the invention is applicable as long as the liquid supply passage36is in communication with a nozzle-opening group that is made up of a plurality of nozzle openings.

Though it is explained above that the bank portion43that includes the stepped surface portion45is formed as a part of the supply member main body31, it is not always necessary to form the step portion45as a part of the bank portion43. That is, a stepped portion may be formed as a part of the metal mold200. For example, a raised surface portion that is elevated toward the supply member main body31may be formed as a part of the metal mold200. A non-elevated area part of the metal mold200is placed in contact with the top surface of the bank portion43. In such a modified structure, the elevated surface portion of the metal mold200, the inner surface of the bank portion43, and the supply member main body31create the inner space204. As another modification example, the supply member main body31may not include the bank portion43. In such a modified structure, it is the metal mold200only that functions as the enclosure of the space204For example, a metal mold may have the shape of a box with one open surface, for example, with an open bottom so that the inner surfaces of the metal mold and the surface of the supply member main body31demarcate the space204.

It is explained above that the position determination concave portions48and the height adjustment convex portions49are formed in the same process as the integral-molding formation of the fixation portion34. However, it is not always necessary to form the position determination concave portions48and the height adjustment convex portions49concurrently with the formation of the fixation portion34. For example, the fixation portion34having a flat surface may be formed first by an integral molding method, followed by the formation of concaves as a result of the removal of a part of the flat surface of the fixation portion34and the formation of convexes as a result of additional mounding of a resin on the flat surface of the fixation portion34. It is not necessary for the fixation portion34, convexes, and concaves to be made of the same resin material. Different materials may be used for the formation thereof.

In the foregoing description of exemplary embodiments of the invention, the ink-jet recording head11that discharges ink drops is taken as an example for the purpose of explaining the concept of the invention. However, the invention can be applied to various kinds of liquid ejecting heads. Liquid ejecting heads to which the invention is applicable include, without any limitation thereto: a recording head that is used in an image recording apparatus such as a printer or the like, a color material ejection head that is used in the production of color filters for a liquid crystal display device or the like, an electrode material (i.e., conductive paste) ejection head that is used for the electrode formation of an organic EL display device or a surface/plane emission display device (FED, field emission display) and the like, a living organic material ejection head that is used for production of biochips.