JP2003226028A - Membrane valve for differential pressure regulating valve, method of manufacturing the same and ink supply vessel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve body for a differential pressure regulating valve capable of lowering a responsive differential pressure by maintaining the durability. <P>SOLUTION: The valve body 2 made of a thermoplastic elastomer is attached to an inner periphery of a ring-shaped frame 1 made of a hard polymer by injection molding. The frame 1 is subjected to an annealing treatment at a temperature whereby the thermoplastic elastomer is not softened and crystallization of the hard polymer can be accelerated. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane valve suitable for a differential pressure valve that opens and closes a flow path in response to a minute differential pressure in an ink supply path or the like.

[0002]

2. Description of the Related Art Ink jet printers use an ink jet recording head that applies pressure to a pressure generating chamber that communicates with a common ink chamber and a nozzle opening to eject ink droplets from the nozzle opening. An ink supply container such as an ink cartridge to be supplied is mounted, and the carriage is reciprocated so that ink droplets are ejected onto a recording sheet in conformity with print data.

By the way, since the nozzle opening of the recording head is located at a position lower than the ink liquid level of the ink cartridge, head pressure acts on the nozzle opening, so that a porous body is usually housed in the ink cartridge. In order to prevent the ink from seeping out from the nozzle opening, the pressure of the ink cartridge is made slightly lower than the nozzle opening due to the surface tension of the porous body.

However, when the ink is consumed and the amount of the ink absorbed by the porous body decreases, the surface tension of the porous body increases and the supply of the ink to the recording head tends to be delayed, so that the inside of the cartridge may be delayed. There is a problem that the above ink cannot be completely consumed. Further, there is a problem that the amount of ink that can be stored in the ink supply container is reduced by the substantial volume of the porous body, and the size of the container is larger than the ink amount.

In order to solve such a problem, for example, as disclosed in Japanese Patent Laid-Open No. 08-174860, a differential pressure valve is provided between the ink supply port and the ink containing chamber to reduce the ink consumption in the recording head. In addition, an ink supply container that opens and closes a differential pressure valve has been proposed. According to this, since the ink can be stored as it is in the ink storage chamber, the porous body is not necessary, and it is possible to provide an ink cartridge most suitable for pigment ink. The valve element that constitutes such a differential pressure valve is required to open and close reliably in response to a small differential pressure, and it is necessary to incorporate it into an ink cartridge that is a supply product, which reduces costs and simplifies the manufacturing process. Therefore, as can be seen in, for example, Japanese Patent Application Laid-Open No. 11-157092, a hard polymer such as polypropylene is used as an annular frame body, and a thermoplastic elastomer, which is a soft polymer, is used as a membrane valve on the inner peripheral side thereof. It is manufactured by two-color molding and insert molding.

[0006]

According to such polymer injection molding, it is possible to manufacture a highly accurate valve body at a low cost and to respond to a smaller differential pressure due to the low rigidity of the thermoplastic elastomer. However, since the thermoplastic elastomer shrinks after injection molding, there is a problem that tension is generated between the thermoplastic elastomer and the frame and the minimum responsive pressure rises. In order to solve such a problem, it may be possible to reduce the thickness of the membrane valve, but in consideration of durability and the like, a limit naturally occurs. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a membrane valve of a differential pressure valve capable of lowering the responsive differential pressure while maintaining durability. That is. Another object of the present invention is to propose a method for manufacturing the same membrane valve.
Still another object of the present invention is to provide an ink supply container incorporating a differential pressure valve using the same membrane valve.

[0007]

In order to achieve the above object, in the present invention, a valve body made of a thermoplastic elastomer is formed by injection molding on the inner periphery of an annular frame body made of a hard polymer. In the pressure valve membrane valve, the frame is annealed at a temperature at which crystallization of the hard polymer can be promoted.

[0008]

[Function] The rigid polymer frame is crystallized and contracted by the annealing treatment, and the inner valve body of the thermoplastic elastomer is slightly compositionally deformed so as to follow the shape of the frame body, and the tension acting on the valve body is reduced. .

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below with reference to illustrated embodiments. FIG. 1 shows an embodiment of the membrane valve of the present invention, in which an annular frame 1 is made of a hard polymer material such as polypropylene, and the inner surface thereof is polybutadiene and butadiene-styrene random copolymer weight. A valve body 2 of a thermoplastic elastomer made of a block copolymer of a crystalline polyethylene obtained by hydrogenating a block copolymer with a polymer and an ethylene / butylene-styrene random copolymer is built in integrally. The valve body 2 is provided with a thick portion 2a at a joint portion with the frame body 1, a ring-shaped bent portion 2b for relaxing a restraining force in the vicinity thereof, and a through hole 3 at the center thereof. A pressing spring receiving seat 4 is formed on the outer circumference.

As shown in FIG. 2, the manufacturing apparatus for such a membrane valve 10 has a mold cavity 20 in which the overall shape of the membrane valve 10 is the same.
The molds 21 and 22 provided with the above are provided with a first injection port 23 in the region of the frame body 1 and a second injection port 24 on the inner peripheral side, and a valve 26 whose valve opening time is controlled by a timer 25 , 27 to connect a hard polypropylene injection machine 28 and a thermoplastic elastomer injection machine 29.

The molds 21 and 22 are rotated about the region which becomes the flow hole 3, the first valve 26 is opened, and a predetermined amount of hard polypropylene that has been softened by being heated to a predetermined temperature is injected. The injected hard polypropylene receives a centrifugal force and is uniformly distributed outside, and spreads in an annular shape. When the hard polypropylene is hardened to some extent, the second valve 27 is opened to inject the thermoplastic elastomer that is heated to a predetermined temperature and softened, and the thermoplastic elastomer adheres to the inner peripheral surface of the frame body made of the hard polypropylene. In this state, the molds 21 and 22 are molded.

When the membrane valve 10 is taken out of the mold at the stage where the molding is completed, the frame body 1 and the valve body 2 are cooled to room temperature. By this cooling, the thermoplastic elastomer constituting the valve body 2 contracts and is constrained by the frame body 1 to generate tension. Although this tension is slightly relaxed by the bent portion 2b, it becomes lower than the intended elastic modulus, and the minimum operating pressure rises.

Therefore, the injection-molded membrane valve 10 is heated to a temperature at which the thermoplastic elastomer does not soften and the crystallization of the hard polymer material can be accelerated, for example, 90 ° C. to 11 ° C.
Annealing is performed by heating at 0 ° C. for a predetermined time, for example, about 1 hour. By this treatment, the hard polymer material forming the frame 1 is crystallized and slightly contracted, and the valve body 2 of the thermoplastic elastomer is hardly crystallized. As a result, the diameter of the inner peripheral surface of the frame body 1 is reduced relative to the outer periphery of the valve body 2, and the tension of the valve body 2 is relaxed.

A membrane valve 10 was manufactured by two-color molding with a valve body 2 having a thick portion 2a of 1.7 mm and a thin portion of 0.2 mm in a frame 1 having an outer diameter of 19.2 mm and an inner diameter of 17.2 mm. Immediately after molding, the opening of the membrane valve 10 was sealed and the operating load of the valve body 2 was measured and found to be 2.3 g. This same membrane valve 10 was
When an annealing treatment was performed at 0 ° C. for 1 hour, the crystallinity of the frame body 1 was increased by a maximum of several% as compared with that immediately after molding,
Along with this, it contracted about 2%.

The thermoplastic elastomer has a temperature of 100 °
At about C, the composition is slightly deformed by creep, so the operating load of the valve body 2 after annealing was measured.
g, about 22%.

From this, when the annealing treatment is performed to such an extent that the crystallinity of the hard polymer constituting the frame body is increased at least, the frame body contracts slightly and the plastic deformation of the valve body 2 interacts with each other. It was confirmed that it is effective in reducing the operating pressure of the membrane valve 10.

The membrane valve 10 constructed as described above is mounted on the base body 30 as shown in FIG.
The coil spring 31 is set on the valve seat portion 32 and is assembled into a differential pressure valve while being pressed by the valve seat portion 32 with a predetermined pressure. In the differential pressure valve configured as described above, when the fluid flows from the opening 33 of the base body 30, the membrane valve 10 receives the pressure and separates from the valve seat 32 against the pressure of the spring 31. As a result, the circulation port 3 is opened from the valve seat portion 32, and the fluid flows out from the outflow ports 34, 35.

Although the bent portion 2b is formed in the vicinity of the inner circumference of the frame 1 in order to relieve the tension in the above-mentioned embodiment, as shown in FIG. Even if the valve body 2 is formed in a substantially flat plate shape from the thick portion 2a serving as the joining region, the tension acting on the valve body 2 can be relaxed by the above-described annealing treatment.

In the above embodiment, the frame body 1 and the valve body 2 are integrally formed by two-color molding. However, the frame body 1 is manufactured in advance by injection molding of a hard polymer material. Incidentally, even when the valve body 2 is injection-molded by a thermoplastic elastomer in a state of being put in the mold, that is, when the valve body 2 is built by so-called insert molding, the heat shrinks after the injection molding of the thermoplastic elastomer. Is effective in reducing the tension of the valve body 2.

The valve body having such a structure can be used as a differential pressure valve for a flow path which has a small flow path diameter and is required to be opened / closed at a low pressure. It is particularly effective when used by incorporating it into a cartridge or sub tank. Figure 5
An ink cartridge incorporating a differential pressure valve is shown as an example. An ink supply port 40 for connecting to a recording head is formed in a lower portion, and an ink supply port 40 is provided in a container 42 forming an ink storage chamber 41. As shown in FIG. 3, the spring 31 and the valve body 1 are provided in the middle of the flow path between the ink storage chamber 41 and the ink storage chamber 41.
0, the base body 30 is incorporated, and finally the opening of the container 42 is sealed with a lid not shown. In the figure, reference numerals 43, 44,
Reference numeral 45 denotes an atmosphere communication port, an ink injection port, and a filter, respectively.

The ink supply container thus constructed is
When it is connected to the recording head in advance and is used as a sub tank, ink is supplied from the ink injection port 44, and when it is used as an ink replenishing means, that is, when it is used as an ink cartridge, the ink injection port 44 is eliminated, Ink can be stored in the ink storage chamber 41 in advance and used.

[0022]

As described above, in the present invention, the frame constituting the membrane valve is annealed at a temperature at which the thermoplastic elastomer does not soften and the crystallization of the hard polymer can be promoted. As a result, the frame contracts more than during injection molding, and the minimum differential pressure decreases due to plastic deformation of the valve body made of thermoplastic elastomer, without reducing the thickness of the member made of thermoplastic elastomer.
It is possible to realize a differential pressure valve having a low minimum responsive pressure.

[Brief description of drawings]

1A and 1B are a perspective view and a sectional view, respectively, showing an embodiment of a valve element for a differential pressure valve of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of an apparatus for manufacturing the above valve body by two-color molding.

FIG. 3 is a cross-sectional view showing an embodiment of a differential pressure regulating valve composed of the same valve body.

FIG. 4 is a sectional view showing another embodiment of the valve body.

FIG. 5 is a diagram showing an example of an ink supply container using the same valve element.

[Explanation of symbols]

1 frame 2 valve body 2a thick part 2b bend 3 outlets

Claims (3)

[Claims] 1. A membrane valve for a differential pressure valve in which a valve body made of a thermoplastic elastomer is formed by injection molding on an inner periphery of an annular frame body made of a hard polymer, wherein the frame body promotes crystallization of the hard polymer. Membrane valve for differential pressure valve that is annealed at a temperature as high as possible. 2. A step of forming a valve body made of a thermoplastic elastomer on the inner circumference of an annular frame made of a hard polymer by injection molding, and an annealing treatment at a temperature at which crystallization of the hard polymer can be promoted. A method of manufacturing a membrane valve for a differential pressure valve, comprising the steps of: 3. An ink supply container in which a differential pressure valve is mounted in the ink flow passage in a container provided with an ink supply opening and an ink storage chamber connected to the ink supply opening via an ink flow passage, The membrane valve that constitutes the pressure valve is formed by injection molding a valve body made of a thermoplastic elastomer on the inner circumference of an annular frame body made of a hard polymer, and the frame body has a degree of promoting crystallization of the hard polymer. An ink supply container that is annealed by temperature.