JP4160096B2 - Elastic member for ink jet recording apparatus and ink jet recording apparatus - Google Patents

Description

  The present invention relates to an elastic member for an ink jet recording apparatus and an ink jet recording apparatus. More specifically, the present invention is used as a seal member for preventing ink from leaking from a recording head in an ink jet recording apparatus body, and is ejected by a two-color molding method. The present invention relates to an elastic member made of a material that can be molded and has excellent durability, and an ink tank and an ink jet recording apparatus using the elastic member.

2. Description of the Related Art Conventionally, an ink jet recording apparatus is equipped with an ink tank having an ink chamber filled with ink and an ink supply unit that supplies ink to a recording head unit. As a type of the ink tank, for example, ink is supplied to a recording head fixedly attached to the carriage through a tube wound in the apparatus, There are those that are detachable, or those that are integrated with the recording head and detachable from the carriage.
In the former ink tank, ink is supplied by providing a water head difference with respect to the recording head. On the other hand, in the latter, a negative pressure generating source is provided on the ink tank side, so that the recording head is provided. It takes the form of supplying ink.
In recent years, many apparatuses that employ the latter type of ink tank have been proposed in terms of downsizing the apparatus and ease of maintenance.
Such an ink tank is required to satisfactorily supply ink commensurate with the amount of ink ejected from the recording head during recording, and to prevent ink leakage from the ejection port during non-recording.

  As an ink tank satisfying such a requirement, for example, a cartridge in which a recording head and an ink tank are integrated and detachable from a carriage, the ink tank is filled with an absorber (foam). There is something that is. In this way, by filling the ink tank with the absorber, it is possible to maintain a stable ink meniscus at the ink discharge portion of the recording head, and the ink in the ink tank can be maintained by the capillary force of the absorber. Is retained. In this case, it is necessary that almost the entire ink tank is filled with the absorber, and the capillary force is maintained by holding the ink amount slightly smaller than the maximum amount of ink that the absorber can hold. Is used to generate internal negative pressure. Therefore, even when a mechanical shock such as vibration or a thermal shock such as a temperature change is applied to the recording head and the ink tank, there is little ink leakage from the discharge part of the recording head or the atmosphere communication part of the ink tank. , Stable ink retention can be performed.

However, the method in which the entire ink tank is filled with the absorber increases the negative pressure of the absorber as the ink is consumed, resulting in a large amount of ink remaining in the ink tank without being supplied to the recording head. Has the problem of being bad.
In order to solve such a problem, for example, the ink reservoir and the cavity are separated by a wall provided with a through hole in the lower part of the ink tank, and an umbrella check valve is movably provided in the through hole so that the recording head can be moved. There has been proposed an ink cartridge for an ink jet recording head configured to open a valve to discharge ink stored in a tank into a cavity and supply the ink to the recording head when the ink pressure drops (see Patent Document 1). ).
According to this, since it is not necessary to store the absorber in the cartridge, it is possible to increase the substantial ink storage capacity in the tank. However, the umbrella check valve is generally used for supplying ink to the recording head. In order to precisely adjust the image quality, there is a big problem that the offset amount is too large and the ink supply amount fluctuates and the print quality is deteriorated.

On the other hand, when the umbrella check valve is closed, the ink reservoir and the recording head are completely shut off. Therefore, when the ink in the cavity expands by about 2 to 5% due to a change in the environmental temperature, When the pressure rises, the seal at the connection port with the recording head breaks and the ink leaks, or when it is attached to the recording head, this pressure acts on the recording head as it is, and the recording head and the ink There is a problem in that the negative pressure between the tank and the tank cannot be maintained, and ink leaks from the recording head.
Furthermore, this umbrella check valve responds to the oscillation of the ink caused by the movement of the carriage because the valve closing force is weak at a pressure difference of about several tens of millimeters of water to be maintained in order to stably supply ink to the recording head. There is a problem that the stability of printing is inferior.
Therefore, in order to solve the problem of the ink tank equipped with such an umbrella check valve, for example, a pressure difference between the ink chamber and the ink supply unit is provided at a position where the ink chamber and the ink supply unit are divided. Attempts have been made to use an ink tank valve that moves the ink and fills the ink chamber to the recording head unit (see Patent Document 2).

By mounting such an ink tank valve, it is possible to reliably respond to a minute differential pressure with respect to the recording head, and without being influenced by the oscillation of the ink due to the movement of the carriage. Ink can be reliably supplied to the recording head while maintaining a negative pressure suitable for printing, and further, leakage of ink from the ink supply port due to temperature change and leakage of ink from the recording head can be prevented.
In this ink tank valve, an elastic material is usually used, and for example, an elastic material bonded to a plastic substrate is used. Conventionally, thermosetting rubber has been generally used as the elastic material. However, with this thermosetting rubber, it is difficult to perform injection molding with a plastic using a two-color molding method, and the manufacturing cost is high to manufacture the valve, and a member having a desired shape is molded from a material with reduced hardness. There was a problem that it was difficult to vulcanize.
On the other hand, in the replacement ink tank, a foam-like elastic member such as polyurethane foam is attached to the conventional ink supply port to prevent the ink from leaking, but the ink is retained when used for a long time. There is a case where the elastic member is not durable and has excellent durability.
Further, in the ink jet recording apparatus, when the recording apparatus is not operating, the recording head stands by at the end of the main body of the ink jet recording apparatus. In order to prevent ink from leaking from the recording head during such standby, The recording head is accommodated on a seal member disposed along a recess provided in the recording apparatus main body. Usually, a thermosetting rubber is used as this member, but this thermosetting rubber has the same problems as described above.

JP-A-62-2231759 JP-A-8-174860

  Under such circumstances, the present invention is provided in the ink jet recording apparatus main body, and is preferably used as a seal member for preventing ink from leaking from the recording head or drying of the recording head. Elasticity for inkjet printers, which can be injection-molded by the two-color molding method, can be molded and vulcanized with low hardness materials, and has good solvent resistance and durability. It is an object of the present invention to provide a member and an ink jet recording apparatus using the elastic member.

As a result of intensive studies to achieve the object, the present inventors have found that the object can be achieved by an elastic member made of a material containing a thermoplastic elastomer made of a specific block copolymer. I found it. The present invention has been completed based on such findings.
That is, the present invention is an elastic member used in an ink jet recording apparatus for recording ink on a recording medium by supplying ink, and comprising at least one polymer block mainly composed of a vinyl aromatic compound and a conjugated diene compound An elastic member for an ink jet recording apparatus, characterized in that it is made of a material containing a copolymer composed of at least one of polymer blocks mainly composed of the above.
The present invention also provides an ink jet recording apparatus using the elastic member.

  The elastic member of the present invention can be injection-molded with a plastic using a two-color molding method, can be molded and vulcanized with a material with reduced hardness, has good solvent resistance, and is durable. It is excellent, and is particularly suitable as a seal member that is provided in the ink jet recording apparatus main body and prevents ink from leaking from the recording head. Further, it can be effectively used as a seal member such as a coupling portion for connecting the ink supply portion and the recording head.

In the elastic member of the present invention, the material is thermoplasticity of a copolymer comprising at least one of a polymer block mainly composed of a vinyl aromatic compound and at least one polymer block mainly composed of a conjugated diene compound. A material containing an elastomer (hereinafter referred to as a thermoplastic material) is used.
Examples of the thermoplastic elastomer include (1) a block copolymer of crystalline polyethylene obtained by hydrogenating a block copolymer of polybutadiene and butadiene-styrene random copolymer and ethylene / butylene-styrene random copolymer. Polymer,
(2) Obtained by hydrogenating a block copolymer of polybutadiene and polystyrene, a block copolymer of polyisoprene and polystyrene, or a block copolymer of polybutadiene or ethylene-butadiene random copolymer and polystyrene. For example, diblock copolymer of crystalline polyethylene and polystyrene, styrene-ethylene / butylene-styrene triblock copolymer (SEBS), styrene-ethylene / propylene-styrene triblock copolymer (SEPS), etc. Styrene-ethylene / butylene-styrene block copolymer or styrene-ethylene / propylene-styrene block copolymer,
And so on.

Among these, a block copolymer comprising at least one polymer block mainly composed of a vinyl aromatic compound and at least one polymer block mainly composed of a conjugated diene compound, as mentioned in (2). A hydrogenated block copolymer obtained by hydrogenation of a polymer having a number average molecular weight of 30000 or more is preferable from the viewpoint of durability when used as an elastic member for an ink tank. The upper limit is not particularly limited, but is usually about 400,000.
That is, it is obtained by hydrogenating a block copolymer comprising at least one polymer block mainly composed of a vinyl aromatic compound (1 segment) and at least one polymer block mainly composed of a conjugated diene compound. A block copolymer having at least two polymer blocks mainly composed of vinyl aromatic compound and at least one polymer block mainly composed of conjugated diene compound (for example, styrene-butadiene-styrene block) is preferable. More preferred is a hydrogenated block copolymer obtained by hydrogenating a copolymer, a styrene-isoprene-styrene block copolymer, or the like.

Further, as a hydrogenated block copolymer similar to this hydrogenated block copolymer, mainly a modified vinyl aromatic compound to which a molecular unit containing a carboxylic acid group, a maleic anhydride group or a derivative group thereof is bonded is used. A hydrogenated block copolymer obtained by hydrogenating a block copolymer comprising at least one polymer block and at least one polymer block mainly composed of a conjugated diene compound is also preferred.
The content of the amorphous styrene block in the block copolymer is 10 to 70% by weight, preferably 15 to 60% by weight. The glass transition temperature (Tg) of the amorphous styrene block portion is 60 ° C. or higher, preferably 80 ° C. or higher. Also, the polymer at the portion connecting the amorphous styrene blocks at both ends is preferably amorphous, and examples thereof include an ethylene-butylene copolymer, a butadiene polymer, and an isoprene polymer. These blocks or random copolymers may be used.
In addition, although these various thermoplastic elastomers are mainly used independently, you may blend and use 2 or more types.

In the thermoplastic material used for the elastic member of the present invention, a softening agent can be blended as desired for the purpose of reducing the hardness of the thermoplastic elastomer. The softener is not particularly limited and can be selected and used from those conventionally used as plasticizers and rubber softeners. However, a low molecular weight substance having a number average molecular weight of less than 20,000 is used. In terms of physical properties, those having a viscosity at 100 ° C. of 5 × 10 ⁵ centipoise or less, particularly 1 × 10 ⁵ centipoise or less are preferable. Further, from the viewpoint of molecular weight, the number average molecular weight is preferably less than 20,000, particularly 10,000 or less, particularly 5000 or less. As such a softening agent, usually a liquid or liquid at room temperature is preferably used. Moreover, both hydrophilic and hydrophobic softeners can be used.
The softener having such properties can be appropriately selected from various rubber or resin softeners such as mineral oil, vegetable oil, and synthetic. Here, process oils such as naphthenic and paraffinic are exemplified as mineral oils, and as a vegetable oil, castor oil, cottonseed oil, linseed oil, rapeseed oil, soybean oil, palm oil, coconut oil, peanut oil, Examples include wax, pine oil, and olive oil.
Among them, it is one or two or more kinds selected from non-aromatic oils, particularly mineral oil paraffin oils, naphthenic oils, or synthetic polyisobutylene oils, and the number average molecular weight thereof is 450 to 5000. Are preferred.

In addition, these softeners may be used individually by 1 type, and may mix and use 2 or more types if mutual compatibility is favorable.
The blending amount of these softeners is not particularly limited, but is usually selected in the range of 1 to 1000 parts by weight, preferably 1 to 500 parts by weight with respect to 100 parts by weight of the thermoplastic elastomer. If this amount is less than 1 part by weight, sufficient hardness reduction cannot be achieved and the flexibility of the thermoplastic material may be insufficient, and if it exceeds 1000 parts by weight, the softener tends to bleed and the thermoplasticity It causes the mechanical strength of the material to decrease. The blending amount of the softening agent is preferably selected within the above range depending on the molecular weight of the thermoplastic elastomer and the type of other components added to the elastomer.
In the thermoplastic material used for the elastic member of the present invention, the polymer organic material constituting the thermoplastic material preferably has a three-dimensional continuous network skeleton structure. The average diameter of the skeleton is 50 μm or less, preferably 30 μm or less, the average diameter of the cells (mesh) is 500 μm or less, preferably 300 μm or less, and the volume fraction of the polymer organic material is expressed as [volume of polymer organic material / (volume of polymer organic material / ( When the volume of the polymer organic material + the volume of the softening agent)] × 100 (%) is defined, the volume fraction of the polymer organic material is preferably 50% or less, particularly preferably 33% or less.

In addition, in order to obtain a thermoplastic material containing a large amount of softener and a smaller amount of polymer organic material, the solubility parameter value δ = (ΔE / V) ^1/2 ( It is preferable to select both materials so that the difference in ΔE = molar evaporation energy, V = molar volume) is 3.0 or less, preferably 2.5 or less. If this difference exceeds 3.0, the softening agent is difficult to be retained in a large amount due to the compatibility between the two materials, resulting in an obstacle to lowering the hardness of the resulting thermoplastic material, and bleeding of the softening agent is likely to occur. Therefore, it is not preferable.
The thermoplastic material according to the present invention can be blended with a polyphenylene ether resin as desired for the purpose of improving the compression set of the material. The polyphenylene ether resin used here is a homopolymer composed of repeating units represented by the following general formula or a copolymer containing the repeating units.

(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represents a hydrogen atom, a halogen atom or a hydrocarbon group)
As this polyphenylene ether resin, known ones can be used, specifically, poly (2,6-dimethyl-1,4-phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene). Ether), poly (2,6-diphenyl-1,4-phenylene ether), poly (2-methyl-6-phenyl-1,4-phenylene ether), poly (2,6-dichloro-1,4-phenylene) Ethers), and polyphenylene ethers such as copolymers of 2,6-dimethylphenol and monohydric phenols (for example, 2,3,6-trimethylphenol and 2-methyl-6-butylphenol). Copolymers can also be used. Of these, poly (2,6-dimethyl-1,4-phenylene ether) and a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol are preferable. Dimethyl-1,4-phenylene ether) is preferred.

The compounding quantity of polyphenylene ether resin can be suitably selected in the range of 10-250 weight part with respect to 100 weight part of thermoplastic materials. If the blending amount exceeds 250 parts by weight, the hardness of the thermoplastic elastomer may be increased, and if it is less than 10 parts by weight, the effect of improving the compression set obtained by blending is insufficient.
Further, the thermoplastic material according to the present invention includes flaky inorganic additives such as clay, diatomaceous earth, silica, talc, barium sulfate, calcium carbonate, magnesium carbonate, metal oxide, mica, graphite, aluminum hydroxide, and the like. Metal powder, wood chips, glass powder, ceramic powder, granular or powdered solid filler such as granular or powdered polymer, and other various natural or artificial short fibers, long fibers (eg, straw, hair, glass fiber, metal Fiber, other various polymer fibers, and the like).

Moreover, weight reduction can be attained by mix | blending an organic hollow filler which consists of a hollow filler, for example, inorganic hollow fillers, such as a glass balloon and a silica balloon, a polyvinylidene fluoride, a polyvinylidene fluoride copolymer, etc. Furthermore, in order to improve various physical properties such as weight reduction, it is possible to mix various foaming agents, and it is also possible to mix gas mechanically during mixing.
In addition to the above components, additives such as known resin components can be used in combination with the thermoplastic material according to the present invention in order to improve various properties.
As the resin component, for example, a polyolefin resin or a polystyrene resin can be used alone or in combination. By adding these, the workability and heat resistance of the thermoplastic material according to the present invention can be improved. Examples of the polyolefin resin include polyethylene, isotactic polypropylene, a copolymer of propylene and a small amount of other α-olefin (for example, propylene-ethylene copolymer, propylene / 4-methyl-1-pentene copolymer). ), Poly (4-methyl-1-pentene), polybutene-1, and the like. When isotactic polypropylene or a copolymer thereof is used as the polyolefin resin, those having an MFR (JIS K7210) in the range of 0.1 to 50 g / 10 min, particularly 0.5 to 30 g / 10 min can be preferably used. .

In addition, as the polystyrene resin, those obtained by any of the radical polymerization method and the ionic polymerization method can be suitably used as long as they are obtained by a known production method. The number average molecular weight of the polystyrene resin is preferably selected from the range of 5,000 to 500,000, more preferably 10,000 to 200,000, and the molecular weight distribution [ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / Mn) ] Is preferably 5 or less.
Examples of the polystyrene resin include polystyrene, styrene-butadiene block copolymer having a styrene unit content of 60% by weight or more, rubber reinforced polystyrene, poly α-methylstyrene, poly pt-butylstyrene, and the like. May be used alone or in combination of two or more. Furthermore, a copolymer obtained by polymerizing a mixture of monomers constituting these polymers can also be used.
The polyolefin resin and polystyrene resin can be used in combination. When these resins are added to the thermoplastic material according to the present invention, when a polystyrene resin is used in combination as compared with the case of adding a polyolefin resin alone, the hardness of the resulting material tends to increase. Therefore, the hardness of the obtained thermoplastic material can also be adjusted by selecting these blending ratios. In this case, the ratio of polyolefin resin / polystyrene resin is preferably selected from the range of 95/5 to 5/95 (weight ratio).

When these resin components are used in combination, they should be used within the range not impairing the effects of the present invention, and the blending amount is preferably about 0 to 100 parts by weight with respect to 100 parts by weight of the thermoplastic elastomer. In the case of a polyolefin resin, 0.1 to 50 parts by weight is particularly preferable. If the blending amount of the resin component exceeds 100 parts by weight, the hardness of the resulting thermoplastic material becomes too high, which is not preferable. In addition, when using polyolefin resin as a resin component, it is more preferable to mix | blend especially the above-mentioned softener in the range of 1-500 weight part with respect to 100 weight part of copolymers (thermoplastic elastomer).
Other additives include flame retardants, antibacterial agents, hindered amine light stabilizers, UV absorbers, antioxidants, colorants, silicone oils, silicone polymers, coumarone resins, coumarone-indene resins, as necessary. Various tackifiers such as phenol terpene resin, petroleum hydrocarbons, rosin derivatives (tackifier), various adhesive elastomers such as Rheostomer B (trade name: manufactured by Riken Vinyl Co., Ltd.), Hibler (trade name: manufactured by Kuraray Other thermoplastic elastomers such as a block copolymer in which polystyrene blocks are connected to both ends of a vinyl-polyisoprene block) and Norex (trade name: polynorbornene obtained by ring-opening polymerization of norbornene). Or resin etc. can be used together.

The silicone polymer has a weight average molecular weight of 10,000 or more, preferably 100,000 or more. The silicone polymer improves the surface tackiness of a molded article using the composition. As the silicone polymer, a general-purpose thermoplastic polymer such as polyethylene, polypropylene, or polystyrene blended at a high concentration can be used in order to improve the handleability. In particular, a blended product with polypropylene has good workability and physical properties.
As such a material, for example, a commercially available silicone concentrate BY27 series general-purpose type commercially available from Toray Dow Corning Silicone Co., Ltd. may be used.
By blending the silicone polymer, the surface condition of the molded product can be improved. However, the miscibility between the silicone polymer and the copolymer comprising a vinyl aromatic compound block and a conjugated diene compound block is not necessarily limited. Not good. This can be easily imagined because the chemical composition of each polymer is significantly different. Accordingly, the silicone polymer may be separated depending on the content of the blend and the molding conditions of the molded body. At that time, a polymer having a relatively good miscibility with a copolymer composed of a vinyl aromatic compound block and a conjugated diene compound block, for example, a graft polymer in which a silicone polymer is chemically bonded to a polyolefin resin is used. Thus, the state can be improved. As such a material, you may use what is marketed as a BY27 series graft type from Toray Dow Corning Silicone Co., Ltd., for example.

The method for producing the thermoplastic material according to the present invention is not particularly limited, and a known method can be applied. For example, the above-mentioned components and optional additive components are melt-mixed using a heating kneader, such as a single screw extruder, twin screw extruder, roll, Banbury mixer, plastic bender, kneader, high shear mixer, etc. It can be easily produced by kneading and further adding a crosslinking agent such as an organic peroxide, a crosslinking aid, etc., if necessary, or mixing these necessary components at the same time and heating and kneading. .
In addition, a thermoplastic material in which a polymer organic material and a softener are kneaded is prepared in advance, and this material is further mixed with one or more kinds of polymer organic materials of the same type or different types from those used here. It can also be manufactured.
Furthermore, the thermoplastic material according to the present invention can be cross-linked by adding a cross-linking agent such as an organic peroxide, a cross-linking aid or the like.

  Here, as a crosslinking agent that can be added for partial crosslinking, an organic peroxide is preferably exemplified, and specifically, for example, 2,5-dimethyl-2,5-di (t-butylperoxy). -Hexane; 2,5-dimethyl-2,5-di (benzoylperoxy) -hexane; t-butylperoxybenzoate; dicumyl peroxide; t-butylcumyl peroxide; diisopropylbenzohydroperoxide; -Bis- (t-butylperoxyisopropyl) -benzene; benzoyl peroxide; 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane and the like, and useful crosslinking aids. Examples of the agent include divinylbenzene, trimethylolpropane triacrylate, ethylene dimethacrylate, Diallyl phthalate, quinone dioxime, phenylene bismaleimide, polyethylene glycol dimethacrylate, and the like unsaturated silane compound. These organic peroxides and crosslinking aids can be arbitrarily used in the range of 0.1 to 5 parts by weight, when the total blending material is 100 parts by weight, and the degree of crosslinking can be adjusted. These organic peroxides and crosslinking assistants can be used in combination of two or more, if necessary. In addition, when an unsaturated silane compound is used as a crosslinking aid, the crosslinking can be further advanced by contacting with moisture in the presence of a silanol condensation catalyst.

The elastic member of the present invention is made of the thermoplastic material described above, and is used in an ink tank having an ink chamber filled with ink and an ink supply unit that supplies ink to the recording head unit.
The elastic member is not particularly limited as long as it is a part that requires the elastic member in the ink tank, and can be used for any part. For example, a position where the ink chamber and the ink supply unit are divided. And an ink tank valve that moves due to a pressure difference between the ink chamber and the ink supply unit and supplies ink filled in the ink chamber to the recording head unit, or is provided at an ink supply port of the ink tank, It is particularly preferable to use the ink tank as a seal member for preventing ink leakage from the ink supply port.
By using a thermoplastic material containing a thermoplastic elastomer such as SEBS or SEPS as described above for these elastic members, the following effects can be obtained.
The ink tank valve usually has a structure in which an elastic material is integrally formed on the surface of a plastic substrate. When a molded product having such a structure is manufactured, the process is simple and the manufacturing cost is low. The injection molding by the two-color molding method with low is advantageous. With thermosetting rubbers conventionally used as the elastic material, two-color molding with plastics was difficult, but by using a material containing a thermoplastic elastomer such as SEBS or SEPS as in the present invention, Two-color molding is possible, and an ink tank valve can be produced at low cost.

In addition, with conventional thermosetting rubbers, it has been difficult to form and vulcanize a member having a desired shape with a low hardness material. However, as in the present invention, it includes thermoplastic elastomers such as SEBS and SEPS. This can be achieved by using a material, and a molded article having appropriate elasticity and excellent mechanical properties can be obtained.
Furthermore, in the thermoplastic material used in the present invention, a liquid having a greatly different polarity with respect to the ink, such as paraffinic oil, is used as an oil component used for reducing the hardness of a thermoplastic elastomer such as SEBS or SEPS. In addition, these oils are hardly compatible with styrene blocks that are aggregation domains of thermoplastic elastomers such as SEBS and SEPS, and have little influence on physical properties such as elastomer strength. In addition, when a thermoplastic elastomer such as SEBS or SEPS is used, changes such as swelling due to a solvent such as ink are small, and ink leaks from an ink tank valve, an ink tank seal member, and a recording head that are excellent in durability. A seal member or the like can be provided.
In addition, the seal member of the present invention can be used not only at the ink supply port but also at a coupling portion for connecting the ink supply portion and the recording head.
The present invention also provides an ink tank using an elastic member composed of a material containing a thermoplastic elastomer such as SEBS or SEPS, particularly preferably an ink tank valve and / or an ink tank seal member.
The ink tank of the present invention is not particularly limited as long as it uses the elastic member, and may be one in which the ink is held by a foam such as polyurethane, and is filled with such a foam. It may not be.

  The shape of the ink tank valve or the ink tank seal member is not particularly limited, and examples thereof include those having the same shape as those used in conventional ink tanks. As for these production methods, for example, in the case of a seal member of an ink tank, conventionally known molding methods such as injection molding and extrusion molding can be employed. On the other hand, in the case of an ink tank valve, for example, plastic as a base material is melt-injected into a mold, and then the thermoplastic material according to the present invention is melt-injected and molded on the surface of the plastic molded product. A two-color molding method in which thermoplastic materials are laminated and integrated can be employed. Alternatively, first, after the plastic is melt-injected into a mold, the molded product is inserted into another mold, and the thermoplastic material according to the present invention is melt-injected and molded on the surface thereof. An insert molding method in which the thermoplastic material is laminated and integrated on the surface can be employed.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
The physical properties in the following examples, comparative examples and reference examples were evaluated by the following methods.
(1) Material hardness It conformed to JIS K6301 (A type).
(2) Bleeding amount of softening agent A sample having a diameter of 25 mm and a thickness of 2 mm is sandwiched between iron plates, compressed until the thickness of the sample becomes 1 mm, and left at 70 ° C. for 48 hours, and then the weight of the sample is measured before compression. The value subtracted from the weight of the sample was taken as the bleed amount of the softening agent and expressed as a percentage by weight (%).
The solubility parameter (SP value) of the copolymer is measured by a conventional method, and the number average molecular weight is measured by gel permeation chromatography [GPC: manufactured by Tosoh Corporation, GMH-XL (two in series)]. Using a differential refractive index (RI), the measurement was performed in terms of polystyrene using monodisperse polystyrene as a standard.

Examples 1 3 and Comparative Examples and Reference Example 1-4
(1) Preparation of thermoplastic material (raw material for ink tank elastic member) Each component having the composition shown in Table 1 was sufficiently kneaded to prepare a sample of the thermoplastic material, and the physical properties were evaluated.
As a result, as is apparent from Table 1, almost no bleed was observed in the materials of Examples 1 to 3 , but the amount of bleed was large in the material of the comparative example. Was observed.

(2) Preparation of Ink Tank Valve Next, an ink tank valve was prepared using the thermoplastic material obtained in (1) above under the manufacturing conditions of a mold temperature of 80 ° C. and a resin temperature of 190 ° C.
The valve thus obtained was mounted at a position where the ink chamber of the ink tank and the ink supply unit were divided, and an ink supply test and a long-term durability test (120 ° C., 1000 hours) were performed. The results are shown in Table 1. Here, the ◯ mark indicates that there is no contamination of the ink by bleed and that it functions sufficiently as a valve. On the other hand, x indicates that the ink is contaminated by bleeding, and-indicates that measurement is not possible.
As a result, in Examples 1 to 3 , both properties (ink supply performance and durability) were satisfactory, but the material of the comparative example had poor adhesion to polypropylene resin and could not be used as a valve. Even in the materials of Reference Examples 1 and 2, contamination of ink due to bleed was observed during the durability test.

(3) Preparation of ink tank seal member Next, using the thermoplastic material obtained in (1) above, an ink tank seal member is prepared under the manufacturing conditions of a mold temperature of 80 ° C and a resin temperature of 170 ° C. did.
The seal member thus obtained was attached to the end of the ink supply unit, and a long-term durability test (120 ° C., 1000 hours) was performed. The results are shown in Table 1.
Here, a circle indicates that there is no ink contamination due to bleeding, and there is no ink leakage. On the other hand, x indicates that the ink is contaminated by bleeding, and-indicates that measurement is not possible.
As a result, ink leakage or the like was not observed in Examples 1 to 3 , and good durability was obtained. However, the material of the comparative example had poor adhesion to polypropylene resin and could not be used as a sealing member. Even in the materials of Reference Examples 1 and 2, contamination of the ink due to bleeding was sometimes observed during the durability test.

Description of Examples Compounding Materials Polymer A: SEPS polymer having a number average molecular weight of 100,000, SP value of 8.5
Polymer B: SEPS polymer with a number average molecular weight of 70,000, SP value of 8.5
Polymer C: SEBS polymer having a number average molecular weight of 50,000, SP value of 8.5
Softener A: Paraffinic oil [manufactured by Idemitsu Kosan Co., Ltd., trade name: PW380] (number average molecular weight 750, SP value 7.8)
Additive A: Polypropylene resin additive B: Equivalent mixture of silicone polymer and polypropylene resin Additive C: Silicone polymer additive grafted on polypropylene resin D: Carbon black additive E: Sulfur additive F: Polyphenylene Ether resin

Claims (4)

An elastic member used in an ink jet recording apparatus for recording ink on a recording medium by supplying ink, and a polymer mainly composed of a conjugated diene compound and at least one polymer block mainly composed of a vinyl aromatic compound It is composed of a material comprising 100 parts by weight of a copolymer comprising at least one block, 0.1 to 50 parts by weight of a polyolefin resin, and 1 to 500 parts by weight of a softening agent, and measured in accordance with JIS K6301 (A type). An elastic member for an ink jet recording apparatus , having a hardness of 30 or less, provided in a main body of the ink jet recording apparatus, and used as a seal member. Claim 1 Symbol mounting of the ink jet recording apparatus elastic member number average molecular weight of the copolymer is equal to or 30000 or more. The polyolefin resin is, according to claim 1 or 2 jet recording apparatus elastic member, wherein the silicone polymer are chemically grafted polymer conjugated. An ink jet recording apparatus characterized by using an elastic member according to the ink jet recording apparatus main body portion to one of claims 1 to 3.