JP2002331668A - Liquid discharge head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance rigidity of an orifice plate by enhancing the molding accuracy or filling performance at the time of manufacturing a top plate constituting a liquid discharge head, and to obtain a high density or long liquid discharge head by suppressing deformation or warp of the top plate. SOLUTION: A top plate 5 constituting a liquid discharge head is divided into a first base body 21 comprising a nozzle array 7 and the ejection opening peripheral part 6c of an orifice plate, and a second basic body 22 comprising the outer circumferential part 6d of the orifice plate, a liquid chamber 8 and a liquid supply opening 9 wherein the first base body 21 and the second basic body 22 are jointed integrally by two color molding. When the first base body 21 is molded of transparent polysulfone, fine shape thereof can be filled efficiently and can be molded with high precision. When the second basic body 22 is molded of resin containing a filler, rigidity of the top plate or the orifice plate is enhanced and a high density or long liquid jet head can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a liquid discharge head for discharging a liquid such as ink from a discharge port as flying liquid droplets to perform printing and recording on a recording medium and to form an image.

[0002]

2. Description of the Related Art A liquid discharge apparatus discharges a liquid such as ink as droplets from a discharge port provided in an orifice plate of a liquid discharge head and attaches it to a recording medium such as a recording paper to form print recording and image formation. Droplets are ejected from ejection openings by driving ejection energy generating elements, such as piezo elements and electrothermal transducers, provided in the liquid ejection head based on drive signals corresponding to recording information and image information. I do.

As an ejection energy generating element, specifically, an electrothermal converting element (heating element) that generates heat when energized according to recording information or the like is used, and heats a liquid in a liquid flow path. A bubble is formed by causing a state change in the liquid, and the liquid is discharged based on the volume change at the time of the formation of the bubble. This type of discharge energy generating element is a thin film forming technology in a semiconductor field on a silicon substrate. It is formed using.

[0004] Such a liquid ejection head is generally
An element substrate on which a plurality of ejection energy generating elements are arranged,
It is composed of a top plate that covers the upper part,
An orifice plate having a plurality of liquid flow paths (nozzle rows) and discharge ports respectively facing the discharge energy generating elements on the element substrate, a liquid chamber for supplying liquid to each liquid flow path, and supplying a liquid to the liquid chambers And a liquid supply port.

The orifice plate is a sheet member having a size of several tens μm to several hundreds μm, and the sheet member has a large number of fine holes as discharge ports.
As a method for efficiently forming these fine holes with high precision, laser processing, electroforming, precision press processing, precision molding, and the like are used.

On the other hand, the liquid flow path is formed by a groove having a width of several tens μm and a depth of several tens μm.
Are arranged at a small pitch. Precision molding such as injection molding, transfer molding, compression molding, extrusion molding, casting, ceramic injection, metal molding, etc., so that such fine grooves are arranged with high precision facing the ejection energy generating element, Laser, Y
It is manufactured by fine processing such as AG laser, anisotropic etching of silicon, and a semiconductor thin film forming technique such as photolithography.

[0007] The top plate can be formed by the above-mentioned various kinds of precision processing. Among them, the method of precision molding is very effective in that members can be manufactured at low cost and that a complicated shape can be easily formed. Yes, it is used in the manufacture of various types of top boards.

In a manufacturing method for forming a top plate by precision molding, there are a case where the nozzle row is transferred and formed from a mold at the time of molding, and a case where the nozzle row is processed and formed by excimer laser processing after the formation of the top plate. Generally, the density of the liquid flow path is 400 dp
In the case of a top plate having a length of i or less, or a top plate having a total length of the liquid flow passage of several tens mm or less, the liquid flow passage is formed by molding,
On the other hand, in the case of a high-density type top plate having a liquid flow path of 600 dpi or more, or a long type top plate having a liquid flow path total length of 100 mm or more, the liquid flow path is formed by excimer laser processing. .

When the orifice plate is made of a resin material, the discharge port is generally formed by excimer laser processing.

In the orifice plate, the portion where the discharge port is formed has a very small thickness of several tens of μm. The thickness of the orifice plate cannot be increased so much because the discharge port area is reduced, the liquid discharge amount is reduced, and the discharge becomes unstable.

The fine orifices formed on the orifice plate are parts that determine the liquid discharge direction, liquid discharge speed, discharge accuracy, and the like. The formation of the discharge ports affects the discharge performance of the liquid discharge head. Has become an important factor.

Therefore, the orifice plate is required to have good workability of fine discharge ports and excellent ink resistance.

As the molding resin material, polysulfone,
Polyether sulfone, polyphenylene sulfide, modified polyphenylene oxide, polypropylene,
A resin material having excellent ink resistance such as polyimide and liquid crystal polymer (LCP) is used.

In forming such a top plate, it is required that the thin or thick portion of the orifice plate can be filled, and that the fine portion of the liquid flow path wall can be transferred stably. Due to the increasing difficulty, it is very difficult to stabilize molding accuracy and maintain its quality.

Injection molding mainly consists of two steps, an injection step and a pressure-holding step. In the injection step, the resin must flow through the entire area inside the mold as quickly as possible before the resin cools and solidifies. However, in the injection process stage, the resin flow is stagnant in the region where the resin flow is stagnant or in a minute portion, so that the resin is insufficiently filled, but the mold is not filled due to the holding pressure applied in the next pressure holding process. Since the internal resin is pushed from the upstream side by another stage, the unfilled portion is completely filled. Therefore,
It is important that such a holding pressure efficiently acts on the fine shape region.

In a conventional top plate, by disposing a fan gate 150 as shown in FIG. 8 on the back surface of the top plate 110, resin is injected from a wide area on the back surface of the top plate.
Care has been taken to ensure that the resin flows efficiently throughout the top plate. In addition, the selection of the fan gate narrows the area near the gate, so the resin that passes through this area actively generates heat due to shearing and improves the fluidity of the resin. Can be done.

The orifice plate may be formed integrally with the top plate, or may be formed separately from the top plate. The configuration of both top plates is appropriately selected depending on the overall component configuration, the configuration of the assembling apparatus, the laser processing method, and the like, but in any case, an advanced fine molding technique is required.

FIG. 9 shows a schematic configuration of such a liquid discharge head. In FIG. 9, the liquid ejection head includes an element substrate 100 on which a large number of ejection energy generating elements (heating elements) 101 are disposed, a liquid chamber 111 joined to the element substrate 100 and containing a liquid, and a liquid flow path ( The liquid chamber 11 includes a top plate 110 having an uneven portion forming a nozzle row) 112.
A liquid supply port 114 that communicates with the liquid chamber 111 is formed in an upper part of 1.

An orifice plate 115 having a discharge port 116 for discharging liquid is formed integrally with the top plate 110 or in front of the liquid flow path 112.
The discharge port 116 is connected to the liquid flow path 112 by being joined or engaged with the liquid passage 112.

The element substrate 100 is bonded and fixed to a support substrate (base plate) 120 with an adhesive 122 or the like, and the top plate 110 is connected to the heating element 101 serving as a discharge energy generating element and disposed on the element substrate 100. Board 110
The orifice plate 115 is aligned with the liquid flow path 112 of the
Is arranged so as to hang forward on the front end face of the camera. The liquid chamber 111 of the top plate 110 receives a supply of liquid from a liquid storage tank (not shown) via a liquid supply port 114.

In such a liquid discharge head, the liquid flow path wall 113 and the element substrate 100 are joined to form the liquid flow path 11.
When forming the liquid channel 2, if the liquid channel wall 113 and the element substrate 100 are joined with a bonding agent such as a sealant or an adhesive,
There is a possibility that these bonding agents may enter the inside 12, change the shape of the liquid flow channel 112, or block a part of the liquid flow channel 112. Therefore, bonding is performed by mechanically pressing at least the liquid flow path wall portion. The configuration will be described below.

The positioning of the element substrate 100 and the top plate 110 in the liquid discharge direction is performed while the front end of the element substrate 100 is abutted against the orifice plate portion 115.
The element substrate 100 and the top plate 110 are joined together, and then the claws 131 provided at the lower ends of both ends of the pressing spring 130 are inserted into the holes 121 provided in the support substrate 120, and the bent portions 13 are formed.
2 is hooked on the lower surface of the support substrate 120. Accordingly, the presser spring 130 linearly presses the upper side of the liquid flow path wall 113 of the top plate 110, so that a mechanical pressure can be applied to the contact portion of the top plate 110. Therefore, the liquid flow path wall 113 of the top plate 110 and the element substrate 100 are brought into close contact with each other by the pressing force of the pressing spring 130.

However, the liquid pressure wall 113 and the element substrate 100 can be brought into close contact with each other by mechanical pressing as described above, but the pressing force acts on other joints such as the outer wall of the liquid chamber 111. And it becomes difficult to ensure close contact. For this reason, a sealant is often used for these portions to enhance the airtightness of the liquid discharge head. Therefore, the sealant is used at the joint between the members that come into contact with the liquid in the liquid ejection head to prevent the liquid from leaking.

[0024]

By the way, in a liquid ejecting apparatus as an output device such as a personal computer terminal, a copying machine, a facsimile, etc., a resolution equivalent to a silver halide film will be obtained in the future, and further, a laser beam printer will be required. In the liquid ejection head, it is required to increase the resolution of the liquid discharge head by increasing the arrangement pitch of the liquid flow paths and increase the arrangement length of the discharge ports. Therefore, it is necessary to discharge the liquid at a higher speed.

However, in a conventional molding method in which a fan gate is provided on the back surface of the top plate (see FIG. 8), the resin injected from a wide area on the back surface of the top plate receives the liquid in the upstream liquid chamber, After passing through the shape forming area such as the liquid supply section, the liquid reaches the liquid flow path wall, so that the pressure loss in the middle path tends to increase, and the injection pressure and the holding pressure are hardly transmitted to the liquid flow path wall. Could be. Therefore, it is difficult to reliably fill all the liquid flow path walls with a top plate having a high-density liquid flow path or a long plate having a long liquid flow path arrangement length. This is a molding method that is not suitable for the top plate of the above-described embodiment.

Generally, the lower surface of the liquid flow path wall of the top plate is several μm
A degree of warpage has occurred, and the upper surface of the liquid flow path wall is pressed downward by linear pressing of the pressing spring, thereby correcting the warpage of the lower surface of the liquid flow path wall while maintaining the lower surface of the liquid flow path wall as an element. Adhered to the substrate. When the top plate is brought into close contact with the element substrate by such mechanical pressing, internal stress and internal distortion are generated around the liquid flow path wall, and further, the orifice plate is affected by the distortion. The part also follows and warps. At this time, in the orifice plate, the orifice plate surface warps in the liquid discharge direction, or the orifice plate surface tilts upward or downward,
The relative orientation and relative position of the plurality of discharge port arrays arranged on the orifice plate will change. If the amount of change in the relative position of the ejection port array becomes large, the landing accuracy of the liquid droplets deteriorates, and the print quality deteriorates.

The deformation factors of the orifice plate portion include a distortion generated by such mechanical joining of the top plate and an internal distortion generated by an internal stress caused by the curing shrinkage of the molding resin. As a matter of course, as the arrangement length of the discharge ports becomes longer and the top plate becomes longer, the deformation of the orifice plate during molding tends to increase.

As a means for reducing the internal distortion of the orifice plate caused by the close contact described above, there is a method of forming the top plate from a material having a large elastic modulus to improve the rigidity of the top plate. However, when the rigidity of the top plate is increased, it is difficult to correct the molding warpage on the lower surface of the liquid flow path wall, which causes a poor adhesion to the element substrate. On the other hand, there is a method of increasing the linear pressing force of the pressing spring, but increasing the linear pressing force increases the internal distortion of the top plate.

In the case where the liquid flow path wall and the element substrate are not sufficiently adhered to each other, the adjacent liquid flow paths among the plurality of liquid flow paths formed by joining the element substrate and the liquid flow path wall are formed by the element. There will be a gap with the substrate. As a result, the discharge energy due to the liquid inertia force generated from the bubble generation process on the heating element is dispersed to the adjacent liquid flow path, and the discharge of the liquid becomes unstable during print recording and image formation. And the droplets are twisted. In addition, when a recording signal is applied, the liquid is not ejected from the ejection port to be ejected, but the liquid is ejected from the adjacent ejection port, which may cause print disorder and may cause deterioration in image recording quality. .

In view of the above, in order to develop an inexpensive liquid ejection apparatus capable of high-speed, high-quality recording, a mold and a molding method that can be developed on a top plate having a high-density liquid flow path or a long top plate have been developed. It is necessary to propose and overcome the conventional problems as described above.

Specific means for solving the conventional problems are that the flatness of the lower surface of the liquid flow path wall is good, that the warpage and deformation around the discharge port are small, and that the rigidity of the top plate is appropriately large. From these developments, to reduce the internal distortion generated in the top plate due to close contact with the element substrate,
This is to maintain the arrangement and orientation of the discharge ports with high precision.

On the other hand, as for the molding resin, selection of a material having high precision and excellent dimensional stability is an important factor that is indispensable for improving the precision thin and thick molding technique. In order to overcome the weaknesses of the top plate, there is a limit in molding using a pure material as before, so the top plate is molded using a molding material that is filled with filler etc. and has enhanced physical properties Such measures are required.

However, molding a top plate from a resin filled with a filler or the like has the following problems.

(1) Problems Related to Laser Processing When the orifice plate is formed of resin, the fine holes provided therein are generally formed by ablation using an excimer laser. However, in the excimer laser processing, the filler portion is not ablated, so that there is a possibility that the filler remains in a protruding shape on the inner surface of the fine hole or the filler is dropped from the surface to form a concave portion, and the inner surface of the fine hole is smooth. No longer
This may cause liquid ejection failure.

(2) Problems Related to Mold Manufacturing The liquid flow path wall of the top plate has a complicated and minute shape, and a mold piece for transferring this portion requires extremely high dimensional accuracy. Since it cannot be easily machined with a general machine tool, it is manufactured using a special precision machining machine and a special material and spending a long time. This is the main factor that makes the production cost of the top plate forming die expensive. Furthermore, in the molding process, this mold piece rubs against the molten resin at the time of injection and rubs against the molded product at the time of release, so that when the top plate is formed from a material containing a filler or the like, the wear of the mold piece becomes faster. Therefore, the durability of the mold is reduced and the productivity of the top plate is reduced.

(3) Problems Related to Material Fluidity In forming a top plate, a material grade having good fluidity is selected in order to surely transfer a fine portion. However, generally, when a filler is contained in a resin, fluidity tends to deteriorate, which is disadvantageous in molding in a form of filling a thin thick portion or a fine portion.

(4) Problems that the filler hinders the flow and filling of the resin The width of the liquid flow path wall is as fine as several μm to several tens of μm, and filler particles such as fibers and beads are formed on the liquid flow path wall. May be larger than the thickness. Therefore, when the top plate is formed of the resin containing the filler, not only the filler is not transferred into the liquid flow path wall, but also the filler stagnates in a state of being bridged at the entrance of the groove portion and flows from the rear. The flow of the molten resin is blocked or the flow is disturbed. Also, when molding with a resin containing a filler, the filler may precipitate on the surface of the molded product,
The filler deposited on the surface may rub against the mold at the time of mold release, and may be missing from the surface layer of the molded product. Furthermore, since the filler is not filled in the liquid flow path wall, the performance improvement effect of the filler is reduced in the liquid flow path wall.

On the other hand, there is a method of forming a top plate with a resin containing an ultrafine powdery filler of about 1 μm to several μm, but the ultrafine powdery filler is uniformly dispersed in a resin base resin. It is very difficult to achieve this, and it is extremely difficult to supply a stable material. In addition, in order to uniformly disperse such a fine powder filler in the base resin, a special dispersion technique and surface treatment of the fine powder filler with a silane coupling agent or the like are required. Is very expensive.

As described above, when the top plate is molded from a resin whose physical properties are enhanced by the inclusion of a filler, the molding accuracy is improved, but the laser processing is hindered, the quality of the molded product is reduced, and the durability of the mold is reduced. It is not always an effective means because it involves an adverse effect such as an expensive molding material.

Therefore, it is difficult to improve the molding accuracy of the top plate, the flatness of the lower surface of the liquid flow path wall, the rigidity of the top plate, and the like by the conventional molding method. Has been an issue.

Next, problems in the use environment and storage environment of the liquid discharge head will be described.

When the temperature fluctuation of the environment in which the liquid discharge head is used becomes large, the individual components constituting the liquid discharge head may expand or contract in volume, which may cause a relative displacement of the head joint. . In particular, in a long head in which a large number of liquid flow paths are arranged, such a relative position shift is accumulated in the liquid flow path arrangement portion, so that a large relative position shift occurs in the liquid flow paths at both ends. become.

Since the liquid flow path formed by the close contact between the top plate and the element substrate has a very fine pitch of several tens of μm, an increase in the relative displacement between them may adversely affect the liquid discharge performance. become.

Further, since the material of the member forming the element substrate and the material of the member forming the top plate are different, a force for moving the relative positions of both members acts. In other words, the element substrate and the top plate individually undergo volume changes due to the internal stress generated from thermal expansion in response to temperature fluctuations, and the bonding interface where the liquid flow path and the heating element face each other is likely to cause relative displacement. I do.

On the other hand, as described above, the liquid flow path wall is mechanically pressed, and the pressing force causes a frictional force to act between the liquid flow path wall and the element substrate. Due to the mechanical strength of the wall itself, relative displacement between the liquid flow path wall and the element substrate is prevented.

However, at the distal end of the discharge port, the effect of such mechanical pressing force is reduced. Therefore, the position between the distal end of the discharge port, the liquid flow path wall, and the element substrate is extremely small, but the relative displacement is small. May have occurred.

The degree of the influence of such a relative positional deviation increases as the density of the nozzle rows increases, and it is difficult to suppress the relative positional deviation. For example, in a liquid discharge head having a discharge port arranged at a resolution of 600 dpi, the width of the front end of the liquid flow path wall is as small as about 7 to 10 μm. The target strength will decrease.

As described above, in the top plate or the long top plate in which the liquid flow paths are arranged at high density, even if the thermal expansion is slight, there is a possibility that the discharge ports at both ends may cause a large relative displacement. are doing.

In order to suppress the relative displacement, there is a method of increasing the linear pressing force of the pressing spring to increase the frictional force of the liquid flow path wall contact surface, but a method of increasing the linear pressing force of the pressing spring is known. As described above, the internal distortion of the top plate increases, which is not very advantageous. Furthermore, in a high-temperature environment, the liquid flow path wall receives the action of thermal stress and the pressure of the presser spring, so if the liquid flow path wall cannot withstand these forces, the liquid flow path wall will undergo plastic deformation such as buckling or bending. Would be.

As described above, in the conventional structure of the top plate formed by molding, it has been difficult to form a top plate having a high-density nozzle or a long top plate by fine molding due to the influence of thermal expansion.

As described above, with the increase in resolution and high-speed printing in the liquid ejecting apparatus in the future, the resin material that can be applied to the top plate is considerably limited. However, it is very difficult to achieve both the molding accuracy and the performance required by the top plate.

Accordingly, the present invention improves the filling properties of the liquid flow path wall and the thin portion of the orifice plate, etc., in order to achieve a high resolution technology and a high-speed printing technology in a future liquid discharge apparatus. The aim is to establish the molding technology corresponding to the top plate, and to improve the overall performance of the orifice by improving the top plate structure, molding accuracy and dimensional stability of the top plate, molding conditions, molding die structure, etc. Provided is a liquid discharge head capable of reducing the deformation of the plate and the warpage of the lower surface of the liquid flow path wall, and by arranging the discharge ports with high precision, improving the landing accuracy of the liquid and improving the print quality. The objective is to overcome the weaknesses in performance, such as thermal expansion and rigidity, which were issues in the conventional top plate.Furthermore, with a high-density nozzle, high speed and high image quality can be obtained. One it is an object to provide a liquid discharge head can be inexpensively manufactured.

[0053]

In order to achieve the above object, a liquid discharge head according to the present invention comprises: an element substrate provided with discharge energy generating elements for applying discharge energy to a liquid corresponding to a plurality of liquid flow paths; A liquid passage groove corresponding to the plurality of liquid passages, an orifice plate provided with discharge ports for discharging liquid in communication with one end of the liquid passage groove, and an orifice plate other than the liquid passage groove. A liquid chamber that communicates with the end and supplies the liquid to the liquid channel; and a liquid supply port that supplies the liquid to the liquid chamber. The liquid channel, the orifice plate, the liquid chamber, and the liquid supply port are provided. In a liquid discharge head that forms the liquid flow path by joining a top plate member integrally formed with the element substrate, the top plate member includes a liquid passage groove and a periphery of a discharge port of the orifice plate. A first base composed of The orifice plate is divided into a discharge port outer peripheral portion surrounding the discharge port peripheral portion and a second base composed of the liquid chamber and the liquid supply port, and the first base and the second base are of two colors. It is characterized by being integrated by molding.

In the liquid discharge head of the present invention, it is preferable that the second base is formed by primary forming and the first base is formed by secondary forming.

In the liquid discharge head of the present invention, the first base is preferably formed of a transparent member, is preferably formed of a pure material, and is preferably formed of polysulfone.

In the liquid discharge head of the present invention, the second substrate is preferably formed of a composite material filled with fillers such as fibers and beads, and further, a base of the material injected into the second substrate. The resin is
It is preferable that the material is the same as the base resin of the material injected into the first base.

In the liquid discharge head of the present invention, the gate for molding the second base is provided on a side surface of the top plate member in the longitudinal direction, and the molding resin is arranged in the liquid flow direction arrangement direction of the top plate member. It is preferable that the gate is configured to flow, and the gate for forming the first base is a two-point gate disposed on both longitudinal side surfaces of the top plate member.

In the liquid discharge head of the present invention, a part of the boundary between the first base and the second base includes a rib, a bellows,
A boss, a seat, or a row of rectangular irregularities is formed, such that the convex portion of the first base enters the concave portion of the second base, and the convex portion of the second base enters the concave portion of the first base. Preferably, the irregularities are formed on a part of the boundary surface near the upper part of the liquid flow channel groove and / or a part of the boundary surface near the lower part of the discharge port.

In the liquid discharge head according to the present invention, it is preferable that the volume of the second substrate is at least four times the volume of the first substrate, and the thickness of the first substrate is 1 m.
m or less.

[0060]

According to the liquid discharge head of the present invention, the top plate member is formed between the first base body composed of the liquid flow channel and the periphery of the discharge port of the orifice plate, and the outside of the periphery of the discharge port of the orifice plate. The first base and the second base are divided and divided into a second base composed of an outer peripheral portion of the surrounding discharge port, a liquid chamber and a liquid supply port, and the first base and the second base are joined and integrated by two-color molding. The base has a simple shape, the flow and orientation of the injected resin are stable, no extra pressure loss occurs during the flow, and the molding accuracy and filling property of the top plate can be improved. By performing two-color molding (or multi-color molding) by combining ceramics, metals, fillers, and the like, it is possible to form a high-precision, multifunctional top plate that could not be realized by molding a single material.

Further, the first base is formed in a fine liquid flow channel, and the second base is formed by dividing a thin orifice plate portion and a high difficulty region in the top plate forming into two steps. The difficulty in the forming step is reduced, and the formability is remarkably improved as compared with the case where the entire top plate is formed at one time.

Further, the first base is formed in a substantially rectangular parallelepiped simple shape around the discharge port and the periphery of the liquid flow channel, and the gate and the liquid flow channel are connected by a substantially linear path. The molding resin injected from the gate smoothly flows to the liquid flow channel without causing a large pressure loss, and the liquid flow channel can be efficiently filled. further,
The resin injection pressure in the injection process stage acts efficiently on the liquid flow path, and the holding pressure in the pressure-holding step is reliably transmitted to the liquid flow path. To be filled. Therefore, transfer of the liquid flow path wall portion can be easily realized even in the molding of the top plate in which the discharge ports, which have conventionally been difficult in injection molding, have a high density of 600 dpi or more.

Further, by forming the top plate in a form of composite molding with different materials, the molding resin of the second base can be molded using various materials, and both can be joined and integrated by two-color molding. By doing so, the completed top plate can be improved in terms of rigidity such as elastic modulus and performance such as thermal expansion.

Therefore, when molding the second substrate, a molding gate is arranged on the side surface in the longitudinal direction of the top plate, and the second substrate is molded with a resin containing a fibrous filler. The fibers of the filler flow in the direction of arrangement of the liquid flow paths in the top plate, and the fibers of the filler are oriented in the direction of arrangement of the liquid flow paths. The second substrate has the rigidity and thermal expansion characteristics of the molding material. The top plate in which the first base and the second base are integrated by color molding obtains rigidity that cannot be obtained by molding with a single material, and significantly improves the thermal expansion characteristics in the liquid flow path arrangement direction.

In other words, since the outer peripheral portion of the discharge port of the orifice plate is formed of the filler-containing resin, even if the liquid flow channel or the discharge port attempts to expand and contract in the liquid flow channel arrangement direction due to environmental fluctuations, the true shape of the liquid flow channel groove. The second base covering the top and the outer periphery of the discharge port works to prevent this, and expansion and contraction of the liquid flow channel and the discharge port in the arrangement direction are suppressed. Further, since the outer peripheral portion of the orifice plate is covered with the filler-containing resin, the rigidity of the entire orifice plate is increased, and the withstand pressure against capping during the recovery operation in the entire apparatus is remarkably improved. As a result, the capping pressure can be set higher, which improves the reliability of the airtightness at the time of capping, and further reduces the distortion of the orifice plate surface that occurs when the top plate and the element substrate are in close contact with each other. Will be done.

Therefore, the combination of the increase in the molding accuracy of the first base and the increase in the rigidity of the second base improves the flatness of the lower surface of the nozzle row, and remarkably reduces the internal distortion of the top plate and the orifice plate. The outlets are arranged with high precision, so that a liquid discharge head that has excellent droplet landing accuracy and can perform stable liquid discharge can be manufactured.

Further, by forming an uneven row such as a rib, a bellows, a boss, a seat, or a rectangle on the boundary surface between the first base and the second base, the bonding area between the first base and the second base is increased. And the bonding between them can be further strengthened. Further, when a resin having a small coefficient of thermal expansion is used for the second substrate, even if the top plate is placed in an environment having a large temperature change and the first substrate attempts to change its volume, This is physically prevented by the irregularities on the boundary surface, so that the volume change of the first base can be more effectively suppressed. Furthermore, if the uneven shape of the boundary portion is formed so that both are undercut in the peeling direction,
Even when the first base and the second base are formed of different materials or the bonding strength is low, the two can be integrated, and the material properties of the second base are weak points of the material properties of the first base. Can be supplemented.

[0068]

Embodiments of the present invention will be described below with reference to the drawings.

A first embodiment of the liquid discharge head according to the present invention will be described with reference to FIGS.

FIGS. 1 and 2 are a schematic perspective view showing an example of the configuration of the liquid discharge head of the present embodiment and a schematic perspective view exploded and shown. FIGS. 3 and 4 show the present embodiment. It is the schematic perspective view and schematic cross section which show an example of the top plate formed by the two-color shaping | molding in an example. And FIG.
FIG. 6 is a schematic perspective view showing an aspect of primary molding of the second base of the two-color molded top plate in the present embodiment, and FIG. It is a schematic perspective view which shows the aspect of shaping | molding.

First, a first example of the liquid discharge head according to the present invention will be described.
The configuration of the embodiment will be described with reference to FIGS.

1 to 4, reference numeral 1 denotes an electrothermal transducer (heat generating element) 1a as an ejection energy generating element for ejecting a liquid such as ink, and wiring for supplying power to the electrothermal transducer 1a. Is an element substrate made of a silicon substrate formed by a silicon film forming process, 2 is a wiring substrate provided with wiring for the element substrate 1 and electrical contacts for the liquid ejection device main body,
A PWB substrate having a wiring pattern formed of copper or nickel on a glass epoxy substrate, a TAB film having a wiring pattern formed on a flexible film, or the like is used. The element substrate 1 and the wiring substrate 2 are electrically connected by, for example, wire bonding.

Reference numeral 3 denotes a support substrate (base plate) formed of aluminum or the like. The support substrate 3 also functions as a heat sink for radiating and cooling the heat of the element substrate 1 generated by driving. The element substrate 1 and the wiring substrate 2 are joined on a support substrate 3, the element substrate 1 is die-bonded on the support substrate 3, and the wiring substrate 2 is adhered on the support substrate 3 with an adhesive or the like.

Reference numeral 5 denotes a top plate forming a liquid flow path.
The orifice plate 6 is formed with a desired number of discharge ports 6a for discharging liquid to the recording medium, and a concave groove is formed on the lower surface of the top plate 5 as a liquid flow path communicating with the discharge ports 6a. A plurality of nozzles (nozzle rows) 7, a liquid chamber 8 formed in a concave shape on the lower surface of the top plate 5 and serving as a sub-tank for supplying liquid to the nozzle rows 7, and a liquid from a liquid storage tank (not shown) to the liquid chamber 8 And a liquid supply port 9 for supplying the liquid.

The orifice plate 6 is shown in FIGS.
As shown in detail, the peripheral portion 6c of the discharge port 6a is the thinnest and has a thickness of several tens of μm, and the rear portion facing the orifice plate surface in the thinnest portion is formed in parallel or substantially parallel. If the thickness of the peripheral portion 6c is increased, the diameter of the discharge port 6 on the surface of the orifice plate may be reduced due to the process of forming the reduced diameter hole by the laser characteristics.
The hole area of “a” becomes small, the liquid discharge amount decreases, and it becomes difficult to discharge the liquid stably. Further, since the laser processing time is long and the processing accuracy is reduced, the laser processing time is generally 20 μm to 70 μm.
It is formed with a very small thickness.

In the nozzle row 7, the thickness of the tip of the groove wall which is the contact surface with the element substrate 1 is several μm to several tens μm, and the depth of the groove is several tens μm to several hundreds μm. It is formed with dimensions.

As described above, since the orifice plate 6 is thin and the nozzle row 7 has a fine shape, the top plate can be formed using a molding material having extremely high fluidity by a high-speed injection molding machine. It has been done. In the orifice plate 6, as described later, a boundary surface 23 a provided near the upper part of the multiple ejection port arrays 6 a,
A boundary surface 23b provided in the vicinity below the discharge port array 6a;
Boundary surfaces 23 provided on both side surfaces in the arrangement direction of discharge ports 6a
With the boundary between c and 23d, the peripheral portion 6c is divided into a peripheral portion 6d surrounding the peripheral portion 6a and the peripheral portion 6c.

Reference numeral 10 denotes a heating element 1 on the element substrate 1.
is a pressing spring for bringing the nozzle row 7 on the top plate 5 into close contact with the nozzle row 7. After the alignment is adjusted so that the relative position between the heating element 1a and the nozzle 7 is completely matched, the pressing spring 10 is moved to the nozzle row. 7 to the top plate 5
Press. That is, a substantially U-shaped bent portion 10a provided at both ends of the holding spring 10 is provided with the hole 3 provided in the support substrate 3.
a, and the claw portion 10 b is hooked on the lower surface of the support substrate 3. As a result, the linear pressure generating portion 10 of the pressing spring 10
c can linearly press the spring receiving portion 5a of the top plate 5 to apply mechanical pressure toward the element substrate 1 to the groove wall lower surface 7a of the nozzle row 7. Due to the pressing of the pressing spring 10, the lower surface 7a of the groove wall of the nozzle row 7 comes into close contact with the element substrate 1, whereby each nozzle 7 is completely partitioned.

The orifice plate 6 is used for the element substrate 1.
Are arranged like a forward hang on the front end face 1b of the device, the positioning of the element substrate 1 and the top plate 5 in the liquid discharge direction is performed as follows.
This is performed so that the front end face 1b of the element substrate 1 abuts against the back face 6b of the orifice plate 6.

Generally, the top plate 5 is warped due to curing shrinkage during molding, and the pressing force of the pressing spring 10 as described above is applied to the back surface 6 b of the orifice plate 6 and the element substrate 1.
Since it does not act in the direction of joining the front end surface of the device, a minute gap is formed between the two surfaces after the top plate 5 and the element substrate 1 are joined. Further, since a small step is provided between the lower surface 8c of the outer wall of the liquid chamber 8 and the lower surface 7a of the groove wall of the nozzle row 7, after the top plate 5 and the element substrate 1 are joined, the outer wall lower surface 8c of the liquid chamber 8 A gap of several μm to several tens μm is formed between the element substrates 1.

Therefore, in order to prevent the liquid from leaking from such insufficiently adhered portions and gaps, a sealing agent such as silicone is injected into the entire bonding interface between the element substrate 1 and the top plate 5. Filling the gap. Specifically, a gap between the back surface 6b of the orifice plate 6 and the front end surface 1b of the element substrate 1, a gap between the back surface 6b of the orifice plate 6 and the front end surface 3b of the support substrate 3, the top plate 5 and the element substrate 1, Sealing of these gaps and joints is performed within a predetermined range by the capillary force generated between the gaps between the members and the sealant. The sealing is performed by devising the shape of the member and controlling the viscosity of the sealing agent so that the sealing agent does not flow outside the range.

However, the back surface 6b of the orifice plate 6
The gap between the substrate and the front end face 1b of the element substrate 1 is very small, and is the most difficult part to inject the sealant. It is necessary to visually confirm that the sealant is filled in a desired range. There is. If the orifice plate 6 is transparent, the filling state of the sealant can be confirmed from the front surface of the orifice plate 6, so that the orifice plate 6 is preferably transparent.

Next, the structure of the top plate formed by two-color molding will be described with reference to FIGS. The top plate 5 is divided into two first bases 21 and a second base 22 at a boundary surface 23 (a, b, c, d), and the first base 21 is provided with a discharge port of the orifice plate 6. Peripheral part 6
c and the nozzle row 7, and the second base 22 has an outer peripheral portion 6 d of the orifice plate 6, a liquid chamber 8, a liquid supply port 9,
It comprises a spring receiving portion 5a and an outer peripheral portion of the top plate. That is, in the orifice plate 6, the nozzle row 7
23a provided near the upper part of the liquid passage portion to which the discharge port 6a is connected, the boundary 23b provided near the lower part of the discharge port 6a, and the boundary provided on both side surfaces in the arrangement direction of the discharge ports 6a. The discharge port peripheral portion 6c and the outer peripheral portion 6d are formed separately at the boundary between 23c and 23d. Then, the first base 21 and the second base 22 are joined and integrated by two-color molding in which the second base 22 is formed by primary molding and the first base 21 is formed by secondary molding. That is, also in the orifice plate 6, the discharge port peripheral portion 6c and the peripheral portion 6d, which are separately formed, are integrated by two-color molding.

The first base body 21 is composed of a discharge port peripheral portion 6c of the orifice plate and a fine portion of the nozzle row 7. For example, a material such as polysulfone, polyethersulfone and the like having good fluidity and suitable for fine molding. Formed by These materials have the necessary conditions for the first base including the discharge port, such as being transparent and excellent in laser workability.

Around the discharge port 6c of the orifice plate
Has a thickness of several tens of μm and has a first substrate 2
1 is a portion where the wall thickness is the thinnest, and if this region is widened, the filling property of the resin is deteriorated. For this reason, a smooth gradient is formed so that the thickness of the lower portion of the discharge port 6a becomes thicker downward from the discharge port peripheral portion 6c. This aims at reducing the pressure loss of the flowing resin to improve the filling property and further increasing the strength of the orifice plate.

Since the first base member 21 is formed of a pure and transparent material (polysulfone, polyethersulfone, etc.) as described above, the first base member 21 is sealed after the top plate 5 and the element substrate 1 are brought into close contact with each other. In the stopping step, it is possible to easily observe the sealing condition at each sealing portion.

Further, since the orifice plate is formed in two parts and is formed by being divided into two steps of the first base and the second base, the orifice plate is formed by one molding as in conventional injection molding. As compared with the case where the molding is performed, the area of the thin thick portion distributed to one molding step is narrowed, the difficulty in filling the resin is reduced, the productivity is remarkably improved, and the molding accuracy is further improved. Will be.

Therefore, dividing the top plate 5 into the first base 21 and the second base 22 and joining them by two-color molding is to improve the molding accuracy of the top plate 5. It is a very effective means. Then, even if both are made of exactly the same material, if they are divided and formed by multi-color molding, the individual substrates are formed with high accuracy, and the forming accuracy of the completed top plate 5 is significantly improved. Further, since both are joined at the time of molding, there is no need for a joining step such as assembly and bonding, and therefore, the productivity is excellent.

On the other hand, the second substrate 22 does not have a finely shaped portion and has a small thin-walled region, so that the transfer accuracy and dimensional accuracy required for the first substrate 21 are not required. In addition, since the outer peripheral portion of the second base 22 plays the role of the housing of the top plate 5, the mechanical properties of this portion greatly affect the performance of the entire top plate. From these points, it is only necessary to select a molding material for the second substrate with emphasis on mechanical properties.

Therefore, if the second base 22 is formed of a resin containing a filler, the second base 22 and the nozzle row 7
The elastic modulus of the peripheral portion of the top plate 5 increases, and accordingly, the top plate 5
The overall rigidity will increase. Furthermore, since the rigidity of the entire orifice plate is improved by increasing the strength of the outer peripheral portion 6d of the orifice plate, the distortion of the orifice plate surface caused when the top plate 5 and the element substrate 1 are in close mechanical contact is reduced. Become like In addition, since the withstand pressure against capping during the recovery operation in the apparatus main body is significantly improved, the capping pressure can be set to a large value, and the reliability for airtightness during capping can be significantly improved.

Therefore, the combination of increasing the molding accuracy of the first base 21 and increasing the rigidity of the second base 22 allows
The flatness of the lower surface 7a of the groove wall of the nozzle row 7 is improved, and the internal distortion of the top plate 5 and the orifice plate 6 is significantly reduced.
With these, the ejection ports 6a are arranged with high precision, and a liquid ejection head that has excellent liquid landing accuracy and can perform stable liquid ejection can be manufactured.

Further, since the second base 22 has no finely shaped portions and has a small thin-walled area, the durability of the mold can be neglected. Therefore, the filler to be filled in the primary molding resin for the second base 22 is various. Material can be selected. Therefore, for the second base 22, it is only necessary to select a material with emphasis on the rigidity surface, and thereby it is possible to optimize the rigidity of the top plate.

Furthermore, magnesium alloy, SUS, iron,
If the second base 22 is formed by MIM (metal injection molding) using a material such as steel or ceramic injection using ceramics, the top plate 5 can obtain rigidity that cannot be obtained by resin molding. Become like

As described above, the nozzle row 7 is generally made of a resin such as polysulfone or polyethersulfone because of molding, sealing, laser processing, and the like. As a result, there is a limit to the low thermal expansion of the first base 21. Therefore,
If the second base member 22 is formed of a material that is resistant to thermal expansion, the formed portion of the second base member 22 structurally compensates for the weak point of the thermal expansion of the formed portion of the first base member 21 and the entire top plate 5. Will be able to do it.

In the orifice plate 6, the boundary surface 2
As shown in FIGS. 3 and 4, reference numeral 3 denotes an upper vicinity (23) of a liquid passage (a portion where the nozzle row 7 and the discharge port 6a are connected).
a), the vicinity (23b) below the outlet 6a, and the outlet 6
Since the second base 22 is formed of a low-thermal-expansion material, the discharge port 6a and the nozzle row 7a become hot in the direction of arrangement when the environment changes due to the fact that they are provided on both side surfaces (23c, 23d) in the direction of arrangement. The second substrate 2
It acts to prevent it due to its thermal expansion properties and stiffness. Further, since both side surfaces of the discharge port peripheral portion 6c are held by the outer peripheral portion 6d of the second base 22, even if the discharge port peripheral portion 6c attempts to expand and contract in the discharge port arrangement direction, the outside of the discharge port peripheral portion 6c. Is physically blocked by the outer peripheral portion 6d that covers.

As described above, since the second base member 22 is formed of the low thermal expansion material, the discharge port 6a and the nozzle row 7 are individually deformed or the nozzle row 7 and the discharge are formed in an environment where the temperature fluctuates rapidly. The relative orientation of the outlet 6a is prevented from changing.

When the molding resin of the second base 22 is made to contain a filler to reduce the linear expansion coefficient of the second base 22, the bonding property between the base resin of the second base 22 and the resin of the first base 21 can be improved. Becomes important. Therefore, it is preferable that a material having good bonding compatibility between the second base 22 and the first base 21 is selected. For example, when the first base 21 is polysulfone, the second base 22 is formed by adding carbon to the base resin polysulfone. When a filler such as a fiber or a glass fiber is filled, the base resin of the two becomes the same, so that the bonding at the boundary surface becomes good during the two-color molding.

Further, when the second base 22 is formed of a resin containing a filler, the second base 22 itself has an effect of improving the molding accuracy. That is, when the filler is filled, the curing shrinkage of the resin at the time of molding is reduced by the filler, so that the molding accuracy of the second base 22 is inevitably improved. As described above, if the forming accuracy of both the first base 21 and the second base 22 is improved, the top plate 5 completed by joining the two is finished into a high-precision molded product.

Next, a molding method for two-color molding of the top plate of this embodiment will be described with reference to FIGS.

FIG. 5 is a diagram showing the primary molding of the second base 22. Reference numeral 31 denotes a side gate for primary molding, which is disposed on one side surface 5 b of the top plate 5. Secondary molding gate 41 to be described later
One of the two places is a side gate 31 for primary molding.
The gate is arranged so as to be in contact with the lower surface of the gate, so that the gate has a two-layer structure of a side gate for primary molding and a side gate for secondary molding.

The primary molding resin is injected into the molding frame of the second base 22 from one side surface 5b of the top plate 5 via the side gate 31. The filler-containing resin as the molding resin injected from the side gate 31 flows along the longitudinal direction of the top plate 5, and the filler fibers contained in the molding resin are oriented along the longitudinal direction of the top plate 5. That is, in the longitudinal direction of the top plate 5, the thermal expansion, the elastic modulus, the curing shrinkage ratio, and other mechanical strengths are effectively exerted in the nozzle array direction by the filler orientation effect.

FIG. 6 is a view showing the secondary molding of the first base 21. Reference numeral 41 denotes a gate for secondary forming the first base 21, and the gate 41 is provided on the side surface of the top plate 5 in the longitudinal direction. However, if the gates 41 (two-point gates) are provided on both sides in the longitudinal direction of the top 5, the flow distance per gate is shortened, so that the two-color molding of the long top can be performed. Be able to respond. That is, the nozzle row portion of the long top plate can be formed by resin molding. Further, as described above, when the secondary molding gates 41 are disposed on both side surfaces of the top plate 5, one side surface becomes a two-layer gate of the primary molding gate 31 and the secondary molding gate 41, and the other side surface. Is a single-layer gate of the secondary molding gate 41 alone.

Next, problems in composite molding using different materials will be described.

For example, the first substrate 21 is made of polysulfone,
When the top plate 5 is integrally formed by two-color molding of the carbon fiber-containing polysulfone of the second base material 22 using different materials, the two-material cured shrinkage ratios are significantly different, so that the cooled two-color molded product is warped. It becomes easy to cause a shape change such as deformation.

That is, since a material having a large curing shrinkage tends to cause a large volume change as compared with a material having a small curing shrinkage, the curing shrinkage stress of one member acts on the other member. At the interface between the two substrates, a bending stress and a shear stress acting to bend the entire molded product act. In the case of a two-color molded part made of a different material, since the base formed by the material having a large shrinkage tends to shrink more, the material having a high shrinkage rate is shrunk in the direction in which the material having a large shrinkage shrinks from the interface between the bases. , The whole top plate will be warped.

Therefore, if the bending rigidity of the molded member made of a material having a small curing shrinkage is larger than the contraction stress generated from a molded member made of a material having a large curing shrinkage, the warpage of the whole molded article can be reduced. That is, the bending stiffness of the member having the small contraction stress (the second base 22),
It can be said that the warpage, deformation, and accuracy of the two-color molded product are determined by the magnitude of the relative difference from the bending stress generated from the member having the large contraction stress (first base 21).

In the two-color molding using such dissimilar materials, the bending stress generated from a member (first substrate) formed of a material having a large curing shrinkage is reduced as much as possible, and the molding is performed with a material having a small curing shrinkage. It is important for the entire molded article to have a strength capable of withstanding the bending stress acting on the interface between the two substrates during cooling of the molded article by increasing the rigidity of the member (second base) as much as possible.

Therefore, the volume ratio of the portion constituted by the first base 21 is made as small as possible, so that the shearing stress acting on the boundary surface during the curing shrinkage and the bending stress acting on the whole molded article are reduced. 22 needs to be formed of a material having high mechanical strength so as to secure rigidity that can withstand bending stress caused by curing shrinkage of the first base 21.

Specifically, the first substrate is polysulfone,
When a top plate having a volume ratio of 4 times or more the volume of the first substrate is formed by two-color molding using polysulfone in which the second substrate contains 20% by weight of carbon fiber. In addition, the warpage generated on the lower surface of the liquid flow path wall can be suppressed to a size equivalent to that of a top plate formed of a single material.

When the first base member 21 is formed with the thickness set to 1 mm or less, the curing shrinkage stress generated from the first base member 21 is reduced, and the top board is less warped or deformed. The accuracy was very good.

Further, the discharge port outer peripheral portion 6 of the second base 22
Since d is configured to cover the peripheral portion 6c of the discharge port of the first base 21, the second base 22 can sufficiently withstand the curing shrinkage stress of the first base 21, and more effective deformation of the top plate can be obtained. Will be suppressed.

The above is an example of the top plate applied to the configuration of the first embodiment of the present invention. However, the present invention can be implemented on any top plate regardless of the form or shape of the top plate. The effect can be expected.

For example, the surface layer of the orifice plate is separated from the main body of the orifice plate, and the surface layer of the orifice plate is molded using a material having good water repellency. Is bonded and integrated by three-color molding, the water-repellent treatment of the orifice plate surface layer, which was conventionally performed by secondary processing, can be performed at the molding process, and the manufacturing process of the top plate can be simplified. .

The portion constituting the first base is not limited to the orifice plate and the nozzle row. The liquid chamber is divided into two parts in the vertical direction, and the lower surface of the liquid chamber is added to the first base. The configuration may be such that all portions that come into contact with the liquid are included in the first base. Further, a configuration in which the periphery of the discharge port and the nozzle row are divided to perform multi-color molding may be adopted.

Next, the second embodiment of the liquid ejection head according to the present invention will be described.
An embodiment will be described with reference to FIG. FIG. 7 is a schematic perspective view showing a first base and a second base in a separated manner for explaining an example of the two-color molded top plate of the present embodiment.

In the above-described first embodiment, the second base member 22 is formed of a material having a small linear expansion coefficient so as to compensate for the weak point of the thermal expansion in the nozzle row 7. If the joining force between the first base 21 and the second base 22 is small, the restraining force of the second base 22 when the nozzle row 7 tries to expand and contract in the arrangement direction is weakened, and the second base 22 is connected to the nozzle row 7 Makes it difficult to compensate for the weak point of the thermal expansion of the. Therefore, in the present embodiment, in the two-color molding, the first base 21
Even if the molding resin of the second base 22 and the molding resin of the second base 22 are difficult to fuse with each other, the weak point of the nozzle row 7 can be overcome.

Hereinafter, a second embodiment of the present invention will be described by assigning the same reference numerals to the same portions as those of the above-described embodiment.

In FIG. 7, reference numeral 51 denotes an array of ribs provided on the boundary surface 23a of the first base 21, and reference numeral 52 denotes an array of ribs provided on the interface 23a of the second base 22. . These uneven rows 51 and 52 are arranged in the same direction as the arrangement direction of the nozzle rows 7 of the first base 21, and the first base 2
The one convex portion 51a enters the concave portion 52b of the second base 22,
The convex portion 52a of the second base 22 is in contact with the concave portion 51b of the first base 21.
Are arranged alternately so as to face each other.

As described above, since the two convex portions 51a and 52a alternately enter the opposing concave portions 51b and 52b, the bonding area of the boundary surface between the first base 21 and the second base 22 becomes large. The bonding strength between the two increases.

Therefore, if the second base member 22 is formed of a material having a small linear expansion coefficient, even if the nozzle row 7 of the first base member 21 attempts to expand and contract in the arrangement direction due to a change in environmental temperature, it is provided on both sides. Due to the physical regulation of the uneven rows 51 and 52, the expansion and contraction of the nozzle row 7 is prevented, and the force for restraining the expansion and contraction of the nozzle row 7 is increased as compared with a top plate having no uneven rows.

Further, if the irregularities are formed in a shape in which both are undercut in the peeling direction, the joining strength of the two substrates is significantly improved by adding physical reinforcement to the fusion strength of the opposing materials. become.

Further, when the uneven rows 51 and 52 at the boundary are formed in an undercut shape, the material of the first base 21 and the material of the second base 22 are unlikely to be fused at the time of two-color molding, and the bonding strength between the two is reduced. Even if the top plate is reduced in size, the uneven rows 51 and 52 can physically restrict expansion and contraction stress in the arrangement direction of the nozzle rows 7 due to thermal expansion and press down. Therefore, if such a configuration is adopted, a combination of molding materials for the first base 21 and the second base 22 can be selected regardless of whether or not the fusibility of both materials is good.

On the other hand, when a material that easily fuses the first base 21 and the second base 22 is selected, the joining area between them becomes large, and the bonding force between them becomes strong in two directions, the peeling direction and the nozzle arrangement direction. Become. Furthermore, if the thermal expansion characteristics of the second base 22 are good, the force for restraining the expansion and contraction of the nozzle row 7 in the arrangement direction in the two-color molded top plate is significantly improved.

The uneven rows may be arranged at equal intervals or irregularly. However, if arranged at equal intervals, the molding resin flows stably and regularly,
In addition to improving the filling property, it also contributes to the effect of suppressing the warpage of the molded product, so that the molding accuracy can be improved.

In the above-described second embodiment, the rib-shaped uneven rows 51 and 52 are provided at the boundary between the first base 21 and the second base 22 as the means for restraining the nozzle row 7. The means is not limited to the rib-shaped concavo-convex array, and the same effect can be obtained with a concavo-convex array such as a bellows, a boss, a seat, and a rectangle.

Further, the uneven rows are not limited to being arranged in the direction in which the nozzle rows 7 are arranged, but may be arranged in the liquid ejection direction.

The nozzle row restricting means is not limited to the concavo-convex row, but may have a structure in which the second base 22 holds both side faces of the nozzle row 7. Also,
A greater effect can be expected by using both the arrangement of the uneven rows and the holding of both side surfaces.

[0128] The uneven row is provided on the boundary surface 23a above the nozzle row 7, but the uneven row is located at the discharge port peripheral portion 6c.
A similar effect can be obtained even if the configuration is provided on the lower boundary surface 23b. Furthermore, if the uneven rows are provided in combination with the boundary surfaces 23a and 23b, the physical effect of the uneven rows by the second base 22 is further improved.

In this embodiment, the weak point of the thermal expansion in the nozzle row 7 has been described. However, the configuration of the second embodiment is as follows.
The second base 22 is also an effective means for improving the rigidity of the entire top plate.

[0130]

As described above, according to the present invention,
The top plate member constituting the liquid discharge head includes a first base including a liquid flow channel and a discharge port peripheral portion of the orifice plate, a discharge port outer peripheral portion surrounding the outside of the discharge port peripheral portion of the orifice plate, and a liquid chamber. Divided into a second base consisting of a liquid supply port and a structure in which the first base and the second base are joined and integrated by two-color molding, the first base has a simple shape, and the resin to be injected is The flow and orientation are stable, no extra pressure loss occurs during the flow, the molding accuracy and filling of the top plate can be improved, and various resins, ceramics, metals, fillers, etc. By performing color molding (or multicolor molding), it is possible to form a high-precision and multifunctional top plate that cannot be realized by single-color molding of a single material. In addition, the first base is formed in a fine liquid flow channel, the second base is formed with a thin orifice plate portion, and a region where the top plate forming is difficult is divided into two steps. In this case, the difficulty of the molding is reduced, and the moldability is remarkably improved as compared with the case where the entire top plate is molded at one time.

The first base is formed in a substantially rectangular parallelepiped simple shape around the discharge port and around the liquid flow channel, and the gate and the liquid flow channel are connected by a substantially straight path. The molding resin injected from the gate smoothly flows to the liquid flow channel without causing a large pressure loss, and the liquid flow channel can be efficiently filled. further,
Since the resin injection pressure in the injection step acts efficiently on the liquid flow path and the holding pressure in the pressure holding step is reliably transmitted to the liquid flow path wall, the finely shaped liquid flow path is Reliable and stable filling is achieved. Therefore, the discharge port which has been conventionally difficult in injection molding is 600 dp.
Even when a top plate having a higher density than i is formed, transfer of the liquid flow path wall portion can be easily realized.

Further, by forming the first base body with a transparent member, the filling condition of the sealant can be confirmed from the front surface of the orifice plate, and the productivity in the assembling and inspection steps is improved. In addition, by forming the first substrate with polysulfone, a transparent orifice plate can be formed, excellent in laser workability and ink resistance for forming the discharge port, and has good fluidity and easy precision molding. In processing the orifice plate, necessary conditions can be ensured. Further, by using a pure material, it is possible to improve the durability of the molding die piece for transferring the nozzle, and to form the discharge port forming surface smoothly when forming the discharge port by laser processing.

[0133] Further, by forming the top plate in the form of composite molding of different materials, it is possible to mold the molding resin of the second base using various materials, and to join them together by two-color molding. By doing so, it is possible to improve in terms of rigidity such as elastic modulus and performance such as thermal expansion, especially,
By molding the second substrate with a composite material filled with fillers such as fibers and beads, molding conditions such as molding shrinkage and anisotropy are improved, and high-precision molding becomes possible. Further, by molding the outer peripheral portion of the orifice plate with the filler-containing resin, the rigidity of the entire orifice plate is increased, and the withstand pressure against capping during the recovery operation in the entire apparatus is remarkably improved. As a result, the capping pressure can be set higher, which improves the reliability of the airtightness at the time of capping, and further reduces the distortion of the orifice plate surface that occurs when the top plate and the element substrate are in close contact with each other. Will be done. Therefore, the combination of the increase in the molding accuracy of the first base and the increase in the rigidity of the second base improves the flatness of the lower surface of the nozzle row, and significantly reduces the internal distortion of the top plate and the orifice plate. It is possible to manufacture a liquid discharge head that is arranged with high precision, has excellent droplet landing accuracy, and can perform stable liquid discharge.

Further, by making the base resin of the material injected into the second base the same as the base resin of the material injected into the first base, the first base and the second base in the multicolor molding can be used. The bonding property is improved, and the completed top plate can be completely integrated as in the case of one-color molding, and can be molded with higher precision than in the case of one-color molding.

By molding the second base with a material having a smaller linear expansion coefficient than the material injected into the first base, the two-color molded top plate in which the two bases are integrated can be formed by the heat of the second base. The expansion characteristic is imparted, so that thermal expansion and contraction around the liquid flow path array and around the discharge port under environmental fluctuations can be suppressed. In addition, since this can be effectively developed even for a top plate having a high-density liquid channel row or a long top plate, various types of top plates can be formed, and the molded top plate can be formed. Can be remarkably improved.

A gate for molding the second base is disposed on the side surface in the longitudinal direction of the top plate member, and the molding resin is configured to flow in the liquid flow direction arrangement direction of the top plate member. In the case where is formed from a material containing a fibrous filler or a material having a large anisotropy, since the orientation of the material generated at the time of molding, such as the orientation of the fiber, can be matched with the arrangement direction of the liquid flow paths, The orientation control can be performed efficiently, and the thermal expansion, the elastic modulus, the molding curing shrinkage, and other mechanical strength can be maximized in the liquid flow direction. Further, by forming the gate for forming the first base as a two-point gate disposed on both side surfaces in the longitudinal direction of the top plate member, the first base can be easily filled, and in particular, the long top plate can be used. In this case, since the moving distance of the resin becomes long, the molding can be easily performed by disposing the multi-point side gate.

Further, by forming an uneven row such as a rib, a bellows, a boss, a seat, or a rectangle on a part of a boundary surface between the first base and the second base, a bonding area between the first base and the second base is formed. Can be increased, and the bonding between the two can be further strengthened. Thereby, if the second substrate is molded from the filler-containing resin, the filler effect reduces the thermal expansion and improves the rigidity of the second substrate,
Even if the liquid flow channel array attempts to expand and contract in the liquid flow channel arrangement direction under environmental fluctuations, the expansion and contraction of the liquid flow channel array can be physically regulated by the rigidity of the second base and the uneven array of boundary surfaces. Therefore, as compared with the case where the uneven row is not provided, the force for restricting the thermal expansion and contraction of the liquid flow channel row is significantly increased, and further, a material is selected so that the first base and the second base are hardly fused. Even in such cases, the action of the uneven row
Since the expansion and contraction stress of the liquid flow path array can be physically restricted and suppressed, the combination of the molding materials of the first base and the second base can be selected regardless of the fusibility of both materials. become.

[0138] Alternatively, a concavo-convex array such as a rib, a bellows, a boss, a seat, or a rectangle may be formed on a part of the boundary surface near the upper part of the liquid flow channel groove or a part of the boundary surface near the lower part of the discharge port. ,
It is possible to further improve the physical effect of the second base on the rigidity and thermal expansion of the uneven rows.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an example of the configuration of a first embodiment of a liquid ejection head according to the present invention.

FIG. 2 is a schematic perspective view showing an exploded example of the configuration of the first embodiment of the liquid ejection head according to the present invention.

FIG. 3 is a schematic perspective view showing an example of a top plate formed by two-color molding in the first embodiment of the liquid ejection head according to the present invention.

FIG. 4 is a schematic sectional view showing an example of a top plate formed by two-color molding in the first embodiment of the liquid ejection head according to the present invention.

FIG. 5 is a schematic perspective view showing a first molding mode of a second base of a top plate in the first embodiment of the liquid discharge head according to the present invention.

FIG. 6 is a schematic perspective view showing an aspect of secondary forming of the first base of the top plate in the first embodiment of the liquid discharge head according to the present invention.

FIG. 7 is a schematic perspective view showing a first base and a second base in a separated state for explaining a configuration of a two-color molding top plate in a second embodiment of the liquid discharge head according to the present invention.

FIG. 8 is a schematic perspective view showing a state of forming a top plate in a conventional liquid ejection head.

FIG. 9 is an exploded perspective view showing a schematic configuration of a conventional liquid ejection head.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Element board 1a Discharge energy generating element (heating element) 2 Wiring board 3 Support substrate 5 Top plate (member) 6 Orifice plate 6a Discharge port 6c Discharge port peripheral part 6d Outer peripheral part 7 Nozzle (row) 7a Lower surface of groove wall (nozzle row) 8) Liquid chamber 8a Liquid chamber upper surface 8c Liquid chamber lower surface 9 Liquid supply port 10 Holding spring 21 First substrate 22 Second substrate 23 (a, b, c, d) Boundary surface 31 Primary molding gate 41 Secondary molding Gates 51, 52 Concavo-convex row

Claims (14)

[Claims] An element substrate provided with a discharge energy generating element for applying discharge energy to the liquid corresponding to the plurality of liquid flow paths; a liquid flow path groove corresponding to the plurality of liquid flow paths; An orifice plate provided with an array of discharge ports for discharging liquid in communication with one end of the passage groove, and a liquid chamber for supplying liquid to the liquid passage groove by communicating with the other end of the liquid passage groove; A liquid supply port for supplying a liquid to the liquid chamber, and a top plate member integrally formed with a liquid flow channel, an orifice plate, a liquid chamber, and a liquid supply port, and by joining the element substrate to the top plate member. In the liquid discharge head forming the liquid flow path, the top plate member includes a first base including the liquid flow path groove and a discharge port peripheral portion of the orifice plate, and a discharge port peripheral portion of the orifice plate. Of the discharge port surrounding the outside of the A liquid discharge head, which is divided into a second substrate comprising a liquid storage chamber and the liquid supply port, and wherein the first substrate and the second substrate are joined and integrated by two-color molding. . 2. The liquid discharge head according to claim 1, wherein the second base is formed by primary forming, and the first base is formed by secondary forming. 3. The liquid discharge head according to claim 1, wherein the first base is formed of a transparent member. 4. The liquid discharge head according to claim 1, wherein the first base is formed of a pure material. 5. The liquid discharge head according to claim 1, wherein the first base is formed of polysulfone. 6. The liquid ejection head according to claim 1, wherein the second base is formed of a composite material filled with fillers such as fibers and beads. 7. The base resin of a material injected into the second substrate is the same as the base resin of a material injected into the first substrate. Liquid ejection head. 8. The method according to claim 1, wherein the second base is formed of a material having a smaller coefficient of linear expansion than a material injected into the first base. Liquid ejection head. 9. A gate for molding the second base is provided on a side surface in a longitudinal direction of the top plate member, and is configured such that molding resin flows in a liquid flow path arrangement direction of the top plate member. The liquid ejection head according to claim 1, wherein 10. The gate according to claim 1, wherein the gate for molding the first base is a two-point gate disposed on both longitudinal sides of the top plate member. Item 2. The liquid ejection head according to item 1. 11. A rib, a bellows, a boss, a seat, or a row of rectangular irregularities is formed on a part of a boundary surface between the first base and the second base, and the convex part of the first base is formed by the convex part of the first base. The liquid according to any one of claims 1 to 10, wherein the liquid enters the concave portion of the two substrates, and the convex portion of the second substrate enters the concave portion of the first substrate. Discharge head. 12. The method according to claim 11, wherein the concave / convex array is formed on a part of a boundary surface near the upper part of the liquid flow channel groove and / or a part of a boundary surface near the lower part of the discharge port. Liquid ejection head. 13. The liquid discharge head according to claim 1, wherein the volume of the second substrate is at least four times the volume of the first substrate. 14. The liquid discharge head according to claim 1, wherein the thickness of the first base is 1 mm or less.