JPH04329149A - Liquid jet recording head - Google Patents

Abstract

PURPOSE:To obtain a highly reliable inexpensive liquid jet recording head through a reduced number of simple manufacturing processes by molding a flow passage substrate using a resin and providing a projecting part having height equal to that of the edge of the recessed part of a common liquid chamber to the interior of said recessed part. CONSTITUTION:Protruding parts 10a, 10b are provided to the interior of the recessed part 6 forming the common liquid chamber of the flow passage substrate 1 of a recording head so as to have height equal to that of the edge of the recessed part 6 and, when the substrate 1 is superposed on a heating element substrate 2, the parts 10a, 10b come into contact with the heating element substrate 2. The flow passage substrate 1 is prepared by the integral molding of a resin. By this method, the deformation of the substrate 1 due to the low mechanical strength of the resin can be prevented and an inexpensive highly reliable, recording head generating no leakage of ink is obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid jet recording head, and more particularly to a liquid jet recording head used in a liquid jet recording apparatus that performs recording using droplets ejected from an outlet.

0002

[Prior Art] Conventionally, this type of liquid jet recording device has been designed to eject minute droplets by generating a pressure change in a liquid flow path by deforming a piezoelectric element, or by further providing a pair of electrodes. There are devices that deflect droplets by using a heating element installed in the liquid flow path, or devices that eject droplets from an ejection port by using thermal energy such as generating air bubbles by rapidly generating heat from a heating element installed in the liquid flow path. Various proposals have been made. Among these, a liquid jet recording head that uses thermal energy to eject a recording liquid has a liquid ejection opening (hereinafter referred to as an orifice) such as an orifice for ejecting recording liquid droplets to form flying droplets. , orifices) can be arranged in a high density, making it possible to perform high-resolution recording, making it easy to make the overall recording head compact, and taking advantage of recent technology in the semiconductor field. It is possible to take full advantage of the advantages of IC technology and micro-processing technology, which are rapidly progressing and improving in reliability, and it is easy to make them longer and planar (two-dimensional).
It is attracting particular attention because it is easy to implement multiple nozzles and high-density packaging, has good productivity during mass production, and can reduce manufacturing costs.

[0003] Examples of methods using this principle include:
A head as disclosed in Japanese Unexamined Patent Publication No. 2-192954 is known. Explaining its configuration here,
A recording head obtained by integrating a top plate (channel plate) formed by resin molding with a heater board is placed on the support, and the urging force of a pressing spring is applied from the top of the top plate to bring it into close contact. The goal is to complete the recording head that has become . This method simplifies assembly of the recording head and has many cost advantages. However, in the case of a small array head with a small number of ejection ports, this method does not cause any problems, but if you try to apply this method to a medium to large array head with a large number of ejection ports, the head As the chip becomes larger, the top plate (channel plate) also becomes longer in the array arrangement direction, so when a biasing force is applied to the top plate,
Because it is made of resin, it flexes, causing problems such as ink leakage because the airtightness of the liquid chamber cannot be maintained.

0004

[Purpose] The present invention has been made in view of the above-mentioned circumstances, and has been made with the object of providing a highly reliable and inexpensive liquid jet recording head that has a simple manufacturing process and fewer steps. It is something.

[0005]

[Structure] In order to achieve the above objects, the present invention provides (1)
A plurality of flow channels, a recess for forming a common liquid chamber for storing recording liquid supplied to the flow channels, and a recess formed in the recess for introducing the recording liquid into the common liquid chamber. a flow path substrate having an inlet, a heating element substrate provided with a thermal energy acting section, a head holding substrate for holding the heating element substrate, and a head holding substrate, the heating element substrate, and the flow path substrate. In a liquid jet recording head comprising a pressing member stacked in order to apply a force to the channel substrate in a direction substantially perpendicular to the plane of the heating element substrate, the channel substrate is formed by molding a resin. and a convex portion having a height equivalent to the edge of the concave portion is provided inside the concave portion, or
(2) A discharge port forming member having a plurality of flow channels and a discharge port formed at one end of the flow channels for discharging recording liquid; A flow path substrate having a recess for forming a common liquid chamber for storing a recording liquid, an inlet formed in the recess for introducing recording liquid into the common liquid chamber, and a thermal energy acting section. A heating element substrate, a head holding substrate for holding the heating element substrate, the head holding substrate, the heating element substrate, and the flow path substrate are stacked in this order, and the heating element substrate is substantially perpendicular to the plane of the heating element substrate. In a liquid jet recording head comprising a pressing member that applies a force in a direction to the channel substrate, the channel substrate is formed by molding a resin, and a convex portion having a height equivalent to the edge of the concave portion is provided inside the concave portion. Furthermore, (3
) In (1) or (2) above, the convex portion is provided in the vicinity of the area of the concave portion that would deflect the most if it were assumed that the convex portion did not exist, and further, (4)
In (1) or (2) above, the convex portion is provided in the vicinity of a region where the largest force acts and a region on the opposite side of the recess wall, or (5) a plurality of flow paths;
It has a recess for forming a common liquid chamber for storing the recording liquid supplied to the flow path, and an inlet formed in the recess for introducing the recording liquid into the common liquid chamber. A flow path substrate formed by resin molding, a heating element substrate provided with a thermal energy acting section, a head holding substrate for holding the heating element substrate, the head holding substrate, the heating element substrate, and the flow path substrate. In a liquid jet recording head comprising a pressing member which applies a force in a direction substantially perpendicular to the plane of the heating element substrate to the flow path substrate by laminating them in this order, a support member is provided in the common liquid chamber. or (6) an ejection port forming member having a plurality of flow channels and an ejection port formed at one end of the flow channels for ejecting recording liquid; a recess for forming a common liquid chamber for storing recording liquid; and an inlet formed in the recess for introducing the recording liquid into the common liquid chamber. A flow channel substrate, a heat generating substrate provided with a thermal energy acting portion, a head holding substrate for holding the heat generating substrate, the head holding substrate, the heat generating substrate, and the flow channel substrate are stacked in this order. In the liquid jet recording head comprising a pressing member that applies a force in a direction substantially perpendicular to the plane of the heating element substrate to the flow path substrate, a support member is provided in the common liquid chamber, further comprising: (7) In (5) or (6) above, the support member is provided in the vicinity of an area of the recess that deflects the most if the support member is not provided; ) In the above (5) or (6), the support member is provided in the common liquid chamber near the area where the largest force acts. Hereinafter, the present invention will be explained based on examples.

FIG. 1 is a perspective view showing an embodiment of a liquid jet recording head according to the present invention, and FIG. 2 shows a flow path substrate (FIG. 2(a)) and a heating element substrate (FIG. 2(b)) constituting the recording head. )), Figure 3 is a perspective view of the channel board seen from the back side.
In the figure, 1 is a channel substrate, 2 is a heating element substrate, 3 is an ink inlet, 4 is an ejection port, 5 is a channel groove, 6 is a recess for forming a common liquid chamber, 7 is an individual lead electrode, 8 is a common lead electrode, 9 is a heating element, and 10a and 10b are convex portions. A heating element 9 is formed on the surface of the heating element substrate 2 along with lead electrodes 7 and 8 . A conventionally known thermal head manufacturing process can be applied to the construction of these lead electrode heating elements, and this process is a well-known technique among those involved. Although only the lead electrodes and the heating element are shown here to simplify the explanation, more precisely, an ink-resistant protective layer, an anti-green layer, etc. (not shown) are provided as necessary. Also, the number of heating elements and discharge ports is only shown as four for the sake of simplicity, but strictly speaking it is several tens to several 1.
00 or more exist.

Next, the channel substrate 1 will be explained. Recess 6
Convex portions as shown at 10a and 10b are provided inside. The height of this convex portion is equal to the height of the edge of the concave portion 6, and when stacked on the heat generating substrate 2 as shown in FIG. 1, the convex portion comes into contact with the heat generating substrate 2. In the present invention, the channel substrate 1 is manufactured by integral molding of resin. As the resin material used, polysulfone, polyethersulfone, polyphenylene oxide, polypropylene, etc., which have excellent ink resistance, are used. Among them, melt flow ra has good fluidity for molding.
It is preferable to use a material having a te of 10 g/10 minutes or more. A commercially available injection molding machine is used as the molding machine, but the injection pressure is 2000 kg/cm in order to accurately transfer the minute shape.
A molding machine with a capacity of cm2 or more is desirable. Further, in order to improve the fluidity of the resin, the cylinder temperature is heated to 400° C. or higher. As the mold, a mold having a shape that is paired with the channel substrate 1 shown in FIG. 3 is used. Further, in order to improve transferability, a heater heat medium or the like is provided in the mold so that the material can be heated to a temperature higher than the thermal deformation temperature of the material of the mold. Note that it is also effective to reduce the pressure in the resin-filled portion of the mold using a vacuum pump or the like to improve transferability.

FIG. 4 is an exploded perspective view of a liquid jet recording head according to the present invention, in which 11 is a holding substrate, 12 is a hole,
13 is an adhesive, 14 is a presser spring, 15 is a hole, 16 is a nail, and other parts having the same functions as those in FIGS. 1 to 3 are given the same reference numerals. The above-described heating element substrate 2 and channel substrate 1 are laminated in this order on the head holding substrate 11, and the laminated body is pressed and assembled using a presser spring 14 having an M-shaped cross section as a pressing member. Reference numeral 13 denotes an adhesive for fixing the heating element substrate 2 to the head holding substrate 11, and an epoxy adhesive is preferably used.

These substrates stacked in the above-mentioned order are stacked from the upper side of the flow path substrate 1 in a direction substantially perpendicular to the plane of the heating element substrate 2 by a presser spring 14 having an M-shaped cross section. A directional force is applied. This presser spring 14 can be formed using, for example, phosphor bronze or a stainless steel plate for springs. Then, by fitting the claws 16 provided at the bottom of both ends into the holes 12 provided in the head holding substrate 11 and engaging them, mechanical pressure is applied from the upper part of the flow path substrate 1 to the heating element substrate 2. It will be applied in a direction almost perpendicular to the plane. As a result, the heating element board 2
Thus, sufficient adhesion between the channel substrate 1 and the flow path substrate 1 can be obtained. In this presser spring 14, reference numeral 15 is a hole that receives the insertion of a supply pipe connecting the ink introduction port 3 of the flow path substrate 1 and the ink supply port on the supply tank side (not shown).

[0010] In the present invention, the heating element substrate 2 and the channel substrate 1
Although sufficient adhesion between the two can be obtained, an adhesive may be interposed between the two, if necessary, in order to improve the sealing performance of the ink. The adhesive used in this case has very little elution with the ink. For example, XB305
An epoxy adhesive called 2 (manufactured by Ciba Geigy) can be used. Suitable curing conditions for this adhesive are obtained by leaving it in an 80°C atmosphere for 8 hours.

As shown in FIG. 3, the channel substrate 1 of the present invention
The concave portion 6 is provided with convex portions such as 10a and 10b. As explained in FIG. 4, this prevents the flow path substrate 1 made of resin from bending when mechanical pressure is applied by the presser spring 14, thereby preventing the inability to maintain the close contact state. It was established for this purpose. This point will be explained using FIG. 5.

FIG. 5(a) shows a channel substrate as shown in FIG.
FIG. 5(b) shows the case where the protrusions 10a, 10b are not provided, and FIG. , furthermore, the force F applied downward by the presser spring 15
FIG. 5C is a cross-sectional view of the common liquid chamber shown in FIG. 5(c) when .

Since the channel substrate 1 of the present invention is manufactured by molding resin, its mechanical strength is weaker than that of metal, etc., and when a force F is applied by a presser spring, it may If the inside of the recess 6 is completely hollow, as shown in FIG. The adhesion cannot be maintained, causing ink leakage. This defect occurs when the head chip is very small (a few millimeters square,
Therefore, it is hardly a problem for medium to large array multiheads (with a head chip of 10 mm square or more and a printing width of 10 mm) for medium to high speed printing.
In the above), since the channel substrate 1 becomes longer in the direction in which the discharge ports are arranged, the amount of deflection increases due to the pressure applied by the pressing member, and the problem becomes serious. However, as shown in FIG. 3, since the convex portions 10a and 10b function as supports to prevent deflection, the deflection disappears, and therefore, the floating at both left and right ends of the channel substrate 1 caused by the deflection also occurs. Instead, as shown in FIG. 5(b), good adhesion between the heating element substrate 2 and the channel substrate 1 is maintained.

[0014] In the above explanation, an example is given in which two protrusions are formed, but in the present invention, the number, shape, and position of the protrusions are not limited to this example. Generally, it is desirable that the convex portion be provided at a location where the maximum deflection occurs when a force is applied by the pressing member and assuming that there is no convex portion. However, in some cases, e.g.
There may be cases where the location where the maximum amount of deflection occurs coincides with the ink introduction port 3. In such a case, the effects of the present invention can be sufficiently exerted even if the convex portion is not necessarily set at a location where the maximum amount of deflection occurs, but at a location convenient for design in the vicinity thereof.

Another suitable location is the location where the force is applied by the pressing member, or if there are multiple forces applied, the vicinity of the location where the resultant vector of those force vectors is maximum, and through the wall of the recess. The convex portion is provided in the area on the opposite side (inside the concave portion). Depending on the structure and method of the pressing member, the location where the amount of deflection is maximum and the location where the maximum force is applied may be the same or different, but the location of the protrusion may depend on other design factors. It is best to make an appropriate decision while also taking into consideration the following.

FIGS. 6(a) to 6(e) show cross-sectional views of other embodiments of the pressing member. In the figure, 17 is a screw, 1
8 is a holding plate, 19 is a coil spring, and 20 is a leaf spring. Figure (a) shows a structure in which a heating element substrate 2 and a channel substrate 1 are placed one on top of the other, a presser plate is applied, and the two are fastened together with screws. Figure (b) shows a structure in which a holding member is fastened with screws from both sides, and the channel substrate 1 is held down by a convex portion in the center of the holding member. Figure (c) shows a structure in which the channel substrate 1 is held down by screws. Figures (d) and (e) are coil springs, respectively.
Alternatively, the structure is such that the channel substrate 1 is held down by the elastic force of a leaf spring.

FIG. 7 is a diagram in which the ink inlet provided in the channel substrate is provided at a different position from that in FIG. For example, when attached to the ceiling of the common liquid chamber as in the case of Fig. 1,
Depending on the structure of the pressing member 14, the ink introduction port 3 may be covered. This is also the pressing member 1 in FIG.
4, this can be solved by providing a hole 15 to avoid this problem, but by providing an ink introduction port 3 on the side as shown in FIG. 7, it is possible to increase the degree of freedom in the structure of the pressing member. can. Furthermore, the position of the convex portion 10c provided within the concave portion is also
Since it is not obstructed by the ink introduction port 3, it can be provided at an optimal position. In the above explanation, the flow path substrate 1 is configured such that the tips of the flow path grooves 5 directly form the ejection ports 4 after the recording head is completed, but in order to stabilize the ejection of ink, the flow path grooves 5 are A configuration may be adopted in which a separate discharge port is further provided at the tip.

FIGS. 8, 9, and 10 are configuration diagrams of the flow path substrate and the heating element substrate, and in the figures, 30 is the flow path substrate, 31, 3
2 is a groove for forming an ink flow path; 33 is a recess for forming a common liquid chamber;
34 is an orifice plate portion, 35 and 36 are orifices, 37a and 37b are heating elements, and 38 is a heating element substrate. The flow path substrate 30 includes a recess 33 for forming a common liquid chamber, a groove 31 for forming an ink flow path communicating with the recess 33 for forming a common liquid chamber,
32, and a desired number of ink ejection ports (orifices) 35, 36 correspondingly formed in the orifice plate portion 34 (two in the figure for simplicity), and are provided integrally with the orifice plate 34. It has a different configuration.

In the configuration example shown in FIG. 8, the channel substrate 30 is made of a resin having excellent ink resistance such as polysulfone, polyethersulfone, prephenylene oxide, polypropylene, etc. It is molded as one piece. On the other hand, in the configuration example shown in FIG. 9, the orifice plate portion 34 is made of the same resin material as the main body portion of the channel substrate 30, or is made of a different type of resin material, or is made of a film made of a metal material. This is manufactured separately from the main body of the channel substrate 30, and inserted into a mold for insert molding. Alternatively, the orifice plate portion 3
4 is manufactured separately from the main body portion of the channel substrate 30 and attached by adhesive.

Next, a method for forming the ink channel grooves and orifices will be explained. For the ink channel grooves, resin is molded using a mold in which fine grooves with a reverse pattern are formed by cutting or other methods, and thereby channel grooves 31 and 3 are formed in the channel substrate 30.
2 can be formed. Regarding the orifice, a piece in the shape of the orifices 35 and 36, for example a cylindrical slide piece, is placed in the orifice molding part in the mold, and after the resin is filled and the resin is cured, the piece is slid and released. can be formed within.

Another method is to mold the mold without orifices 35 and 36 in the mold, and then take it out from the mold from the end surface side of the orifice plate 34 at the position where the orifice is to be formed. For example, the orifices 35 and 36 can be formed by irradiating ultraviolet rays with a laser device to remove and evaporate the resin. Ink channel groove 31
, 32 and the recess for forming the common liquid chamber can also be formed by irradiation with ultraviolet rays from a laser device. At this time, if an excimer laser is appropriately used, precise processing along the mask pattern can be easily performed. In the example, a channel substrate 30 having an ink channel groove width of 30 to 50 μm, a non-groove width of 20 to 40 μm, and an orifice hole diameter of 20 to 40 μm was obtained for the configuration shown in FIG. 8 or 9. Then, as shown in FIG. 10, a heating element substrate 38 having heating elements 37a and 37b is bonded to such a flow path substrate 30 by abutting against the orifice plate portion 34 to obtain a recording head main body.

By the way, the shape of the convex portion provided in the concave portion of the channel substrate is also made at the same time when the channel substrate is made by integral molding of resin, but the shape of the convex portion is formed at the same time as shown in FIG. 5(a). When assembling a recording head by overlapping a heat generating substrate with a flow path substrate that does not have convex portions, the area where the amount of deflection inside the recess is large or the area where a large force F is applied A separately manufactured support member block may be inserted to provide the function of preventing deflection as described above. Such a support member block has a height equivalent to the depth of the recess (that is, the height of the common liquid chamber) and is excellent in vertical parallelism. In addition, if there is a risk that this support member block may move inside the common liquid chamber, use adhesive or the like to fix it to either the heating element substrate side, the flow path substrate side (inside the recess), or both. Bye. The advantage of not providing a protrusion inside the recess is that it can significantly reduce the cost of mold production. Furthermore, retention during molding is also improved. Example 1 FIGS. 11(a) and 11(b) show the dimensions (unit: mm) of the channel substrate. a=5, b=12, c=38, d=3, e=2,
f=3, g=1, h=0.45, i=9.5, j=2.
5, k=3.5. The arrangement density of the channel grooves manufactured by molding using polysulfone as a material was equivalent to 400 dpi, and the number of grooves was 512. The bottom of the recess (thickness of the ceiling of the common liquid chamber) was 1 mm thick. Also, 10a, 1
0b is a convex portion. The flow path board and the heating element board were stacked together and pressed with a phosphor bronze pressing member 14 for a spring as shown in Fig. 4, and ink was poured into the ink introduction port 3 and used as a head. This did not occur. Example 2 The same material as in Example 1 was used, and the pressing member was as shown in Fig. 6(c).
The method was adopted. However, the screw has two protrusions (2m
Two pieces were used so that they were on opposite sides. As a result, no ink leakage occurred. Example 3 Two convex portions (2 mm x 3 mm) of the channel substrate shown in Fig. 11 were scraped off with a knife, and when overlapping with the heating element substrate, the scraped portions were removed and the areas next to them were removed. A cylindrical block of SUS303 with a diameter of 2 mm, a height of 2.5 mm, and excellent vertical parallelism and flatness was arranged to assemble the head. The pressing member adopts the method shown in Fig. 6(b), and 2
It was held down by the elastic force of several coil springs. As a result, no ink leakage occurred. Comparative Example 4 Using the head of Example 3, the head was assembled in the same manner with the cylindrical block removed. As a result, the ink seeped out from between the channel substrate and the heating element substrate, making it unusable. Comparative Example 5 Using the head of Comparative Example 4, a head was assembled by increasing the elastic force of the two coil springs. As a result, ink leakage increased more than in Comparative Example 4, making it unusable.

[0023]

[Effects] As is clear from the above description, the present invention has the following effects. (1) Effects corresponding to claim 1 (configuration 1): In an inkjet jet using a channel substrate whose cost is reduced by resin molding, deformation due to the weak mechanical strength of the resin can be prevented, and the ink We were able to propose an inexpensive and highly reliable head that does not cause leaks. (2) Effects corresponding to configuration 2: This is a head using a method that uses resin molding, and since the ejection opening is provided separately from the above (1), the ink ejection is stable, and the same effect as in the above (1) is achieved. It worked. (3) Effect corresponding to claim 2 (configuration 3): Since the position of the protrusion provided to prevent deformation has been clarified, the position of the protrusion can be determined efficiently. (4) Effect corresponding to claim 3 (configuration 4): Since the position where the force to cause deformation acts is clarified,
The position of the convex portion can be determined efficiently. (5) Effect corresponding to claim 4 (configuration 5): Said (
The same effect as in case 1) can be obtained. Furthermore, by arranging the protrusion as a separate support member within the common liquid chamber instead of making it integral with the channel substrate, the structure of the mold used to mold the channel substrate can be simplified and costs can be reduced. It becomes possible. Furthermore, since the mold has become simpler, there are fewer defects in the manufacture of the channel substrate. (6) Effects corresponding to configurations 6, 7, and 8: (2) above
, (3), and (4) were obtained, and furthermore, the same effects as in (5) were obtained, such as cost reduction due to mold simplification and improvement in retention.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram for explaining one embodiment of a liquid jet recording head according to the present invention.

FIG. 2 is a configuration diagram of a flow path substrate and a heat generating substrate that constitute a recording head.

FIG. 3 is a configuration diagram of the channel substrate viewed from the back side.

FIG. 4 is an exploded perspective view of a liquid jet recording head according to the present invention.

FIG. 5 is a diagram for explaining the state of deflection of the channel substrate.

FIG. 6 is a diagram showing another example of the pressing member.

FIG. 7 is a diagram illustrating different examples of installation positions of ink introduction ports provided on the channel substrate.

FIG. 8 is a configuration diagram of a channel substrate.

FIG. 9 is a configuration diagram showing another example of a flow path substrate.

FIG. 10 is a configuration diagram showing still another example of a channel substrate.

FIG. 11 is a configuration diagram showing still another example of a channel substrate.

[Explanation of symbols]

1... Channel board, 2... Heating element board, 3... Ink introduction port, 4
...Discharge port, 5...Flow path groove, 6...Recessed portion for forming a common liquid chamber, 7...Individual lead electrode, 8...Common lead electrode, 9...
Heating element, 10a, 10b...convex portion.

Claims (4)

[Claims] 1. A plurality of flow channels, a recess for forming a common liquid chamber for storing recording liquid supplied to the flow channels, and a recess for forming a common liquid chamber for introducing the recording liquid into the common liquid chamber. a flow path substrate having an inlet formed in the recess, a heating element substrate provided with a thermal energy acting section, a head holding substrate holding the heating element substrate, the head holding substrate, the heating element substrate, and the heating element substrate. In a liquid jet recording head comprising a pressing member that applies a force to the flow path substrate in a direction substantially perpendicular to the plane of the heating element substrate by stacking flow path substrates in this order, the flow path substrate 1. A liquid jet recording head characterized in that the recess is formed by molding a resin, and has a convex portion having the same height as the edge of the recess. 2. The liquid jet recording head according to claim 1, wherein the convex portion is provided near a region of the concave portion that would deflect the most if it were assumed that the convex portion did not exist. 3. The liquid jet recording head according to claim 1, wherein the convex portion is provided in a region near a region where the greatest force acts and a region on the opposite side of the concave wall. 4. A plurality of flow channels, a recess for forming a common liquid chamber for storing recording liquid supplied to the flow channels, and a recess for forming a common liquid chamber for introducing the recording liquid into the common liquid chamber. A channel substrate formed by molding a resin having an inlet formed in the recess, a heating element substrate provided with a thermal energy acting part, a head holding substrate holding the heating element substrate, and the head holding substrate. A liquid jet recording head comprising: a pressing member that stacks the heating element substrate and the flow path substrate in this order and applies a force in a direction substantially perpendicular to the plane of the heating element substrate to the flow path substrate; A liquid jet recording head according to claim 1, further comprising a support member provided in the common liquid chamber.