JP4100386B2 - Method for selecting material constituting ink flow path of ink jet recording apparatus, and ink jet recording apparatus using the selected material - Google Patents

Description

The present invention provides an ink jet recording apparatus capable of stably obtaining high reliability and high image quality not only in an initial state where ink is filled in an ink flow path of the ink jet recording apparatus but also when there is a temperature change or a change with time. The present invention relates to a method for selecting a material suitable for constituting the ink flow path.

Inkjet recording methods include the bubble method in which ink is ejected from fine nozzles by bubbles generated by rapid heating, and the piezo method in which ink is ejected from fine nozzles using a piezoelectric element that is deformed by voltage application. This is a printing technique in which an image is formed by selectively landing several color inks as droplets of several picoliters to several tens of picoliters on paper. In recent years, downsizing of an ink jet recording apparatus has been studied. For example, in Patent Document 1, an ink holding unit that holds ink is provided separately from the head, and the ink is supplied from the ink holding unit to the head through a tube. Is disclosed.

The advantages of the inkjet recording method are high printing quality and high printing quality by controlling the ejection of minute droplets, and it has a color reproduction close to full color by landing a few picoliters of minute droplets on the paper with high accuracy. In addition, it is possible to form an image without graininess. In order to enable discharge of such minute droplets, high-precision landing control technology from a sufficiently thin discharge nozzle is necessary. In order to enable such precise ink discharge, it is necessary to prevent foreign matter from entering the ink flow path in the apparatus from interfering with the flow of ink. For this reason, the ink flow path is assembled and the ink is manufactured in a clean room, and the ink is subjected to microfiltration with a 0.2 μm membrane filter to prevent contamination by foreign matters.

As a material constituting the ink flow path of the ink jet recording apparatus, generally, a resin or rubber material that is inexpensive and easy to process is used. These resins or rubber materials usually contain many additives in addition to the main component. Examples of such additives include stabilizers such as tin compounds, fatty acid calcium salts, and phosphites to prevent deterioration due to heat during molding; glass for improving heat resistance and wear resistance, etc. Fillers such as silica and metal powders; UV absorbers such as 2-hydroxybenzophenone, triazole and acrylonitrile derivatives to prevent strength reduction due to UV; antimony oxide and barium metaborate to improve flame retardancy Flame retardants such as phosphoric acid esters; Plasticizers such as phthalic acid diesters, dioctyl phthalate, and butanol diesters to adjust processability; Antioxidants to prevent strength reduction due to air oxidation; stearic acid monoglyceride, palmitic acid monoglyceride Antistatic agent for preventing the accumulation of static electricity such as fatty acid glycerides, etc .; Colorant; Mold release Etc. The. Also, among resins or rubber materials, reaction catalysts such as chlorine-based catalysts containing chlorine tetrachloride are always used for those produced using an ion polymerization method such as polyethylene and polypropylene. When these chlorine-based catalysts are used, it is necessary to add a neutralizing agent so as not to corrode the mold during molding. The most commonly used neutralizing agent is calcium stearate. Fatty acid derivatives such as

Some of these additives have the property of eluting in water. Therefore, even if the ink flow path is assembled and manufactured in a clean room, the clean state can be maintained only in the initial stage when the ink flow path is filled with ink, and the ink flow path is filled with ink. When there is a temperature change or a change with time, the additive may elute from the resin or rubber material used in the ink flow path, react with the components in the ink, and generate insoluble matter. When such an insoluble matter occurs, there is a problem that clogging occurs at the nozzle, and high-precision ink ejection is not achieved, resulting in a reduction in image quality.

As a technique for solving such a problem, Patent Document 2 discloses an ink container having a fatty acid or fatty acid derivative content of 100 ppm or less. However, if the content of the fatty acid or fatty acid derivative in the material of the ink container is 100 ppm or less, the range of material selection becomes extremely narrow, which is not realistic. Furthermore, according to the experiment by the present inventors, there was a case where ejection failure that may be caused by elution of fatty acid or fatty acid derivative may occur despite using a material having a fatty acid or fatty acid derivative content of about 50 ppm. .

Japanese Patent Laying-Open No. 2003-175631 (US2003 / 0107625A1) Japanese Patent No. 2658034

The first object of the present invention is to solve the above-mentioned problems, and is stable not only in the initial state where the ink flow path is filled with ink, but also in the case where there is a temperature change or a change with time. Another object of the present invention is to provide a method for selecting a material suitable for constituting an ink flow path of an ink jet recording apparatus that can obtain high reliability and high image quality.

A second object of the present invention is to provide a novel method for evaluating and selecting a material constituting an ink flow path of an ink jet recording apparatus very easily and without analyzing the composition using an expensive analyzer. is there.

According to the present invention, the resin or rubber material in a closed vessel, during heating ink heating the ink used in Lee inkjet recording apparatus, it is a predetermined period immersed; the ink after immersing the resin or rubber material filtered And determining whether or not the resin or rubber material is suitable as a material to be used for at least a part of the ink flow path of the ink jet recording apparatus based on the filtration time. A method for selecting a resin or rubber material used in at least a part of the ink flow path is provided .

In the method of the present invention, the pre-Symbol resin or rubber material, when immersed for two weeks in the ink of 60 ° C. in a closed container obtains the filtration time and filtration of the ink after the immersion, to the filtration time Based on this, the amount of the eluate eluted in the ink can be obtained. At this time, after the ink is kept in a sealed container at 60 ° C. for 2 weeks without immersing the resin or rubber material, the ink is filtered to obtain a reference filtration time, and the reference filtration time and the resin or rubber material are used as the ink. The amount of the eluate eluted in the ink can be obtained by comparing the filtration time when immersed in the ink.

According to the method for selecting a material constituting the ink flow path of the ink jet recording apparatus of the present invention, because of the above-described structure, not only the initial state in which the ink flow path is filled with ink but also a change in temperature and a change with time. Even in this case, it is possible to provide a material constituting the ink flow path of the ink jet recording apparatus that can stably obtain high reliability and high image quality.

As a result of intensive studies, the present inventors have determined that the amount of the eluent such as a fatty acid derivative eluted in the ink does not necessarily depend on the content of an additive such as a fatty acid derivative contained in the resin or rubber material. I found. For example, among additives contained in a resin or rubber material, fatty acid derivatives such as fatty acid salts added as stabilizers, antistatic agents, and neutralizing agents have the greatest effect on the stable ejection of ink from nozzles. It is known from the experiments of the present inventors that the fatty acid derivative may hardly be eluted from the resin or rubber material even if the amount of the fatty acid derivative in the resin or rubber material exceeds 100 ppm. The inventors have found. That is, additives such as fatty acid derivatives may hardly be eluted depending on the type of material or the type and amount of other additives contained even in the same material. Accordingly, in order to provide an inkjet recording apparatus that can stably obtain high reliability and high image quality, the concentration and components of additives such as fatty acid derivatives contained in the resin or rubber material used in the ink flow path. However, the inventors have found that attention should be paid to the amount of an additive such as a fatty acid derivative that is eluted or released from the resin or rubber material into the ink under actual use conditions, and the present invention has been completed. Furthermore, according to the experiments of the present inventors, elution or release of additives such as fatty acid derivatives from the resin or rubber material to the ink is performed by immersing the resin or rubber material in water under predetermined conditions for a predetermined time. It turned out to be more prominent. By using this water immersion method, simple material selection becomes possible.

In the ink jet recording apparatus as an object of the present invention, at least a part of the ink flow path is made of a resin or a rubber material. The type of the resin or rubber material that can be used is not particularly limited. For example, polyolefin resin such as polypropylene resin and polyethylene resin, polyvinyl chloride, polyvinylidene chloride, silicon resin, vinyl acetate copolymer, acrylonitrile-butadiene. -Styrene (ABS) resin, polyacetal resin, nylon resin, fluorine resin, butyl rubber, butadiene rubber, silicon rubber, urethane rubber, styrene rubber, chloroprene rubber, nitrile rubber, ethylene-propylene rubber, fluorine rubber and the like. These resins or rubber materials may contain conventionally known additives such as a stabilizer, an ultraviolet absorber, an antioxidant, and an antistatic agent within a range that does not impair the object of the present invention.

According to the present invention, the resin or rubber material as described above is selected by the following method. First, the resin or rubber material is immersed in water heated in a sealed container for a predetermined period. For example, it can be immersed in water heated to 60 ° C. for 2 weeks. After the immersion, the amount of the eluate such as fatty acid derivative eluted in water is measured. In the case of measuring a fatty acid derivative, a material whose measured value is 20 ppm or less with respect to the total amount of the resin or rubber material when the measurement value is immersed in water heated to 60 ° C. for 2 weeks or less. It can be judged as a suitable material. If it exceeds 20 ppm, the eluted fatty acid derivative reacts with the components in the ink to generate an insoluble matter, which tends to cause ejection failure. Under the immersion conditions, the elution amount of the fatty acid derivative is preferably 18 ppm or less. The fatty acid derivative can be qualitatively and quantitatively combined with conventionally known analysis methods such as FT-IR method, GC analysis method, and GC-MS analysis method.

Or in the said method, it may replace with water and may use the ink used for an inkjet recording device. In this case, the resin or rubber material is immersed in ink heated in a sealed container for a predetermined period. For example, it can be immersed in ink heated to 60 ° C. for 2 weeks. By using the ink, a result in accordance with the actual use state of the ink jet recording apparatus can be obtained. However, according to experiments by the present inventors, it was found that the fatty acid derivative tends to elute at least earlier when the resin or rubber material is immersed in water than the ink. Therefore, when measuring mainly fatty acid derivatives, it is preferable to use water, particularly high-purity water such as distilled water or pure water, as the immersion medium.

Even when ink is used as an immersion medium, eluents such as fatty acid derivatives can be obtained by combining conventionally known analysis methods such as the FT-IR method, the GC analysis method, and the GC-MS analysis method as described above. Qualitative and quantitative are possible. Instead of directly quantifying the amount of eluate such as fatty acid derivatives, the resin or rubber material is immersed in the ink for 2 weeks, then the resin or rubber material is removed from the ink, the ink is filtered, and the filtration time is measured. The amount of eluate such as a derivative can be easily predicted. In this case, without immersing the resin or rubber material in the ink, the filtration time of the ink stored under the immersion conditions is set as a reference value, a predetermined multiple of the reference value is set as a threshold value, and a material exceeding the threshold value is inappropriate. be able to. Alternatively, in advance, an ink containing a known amount of an additive such as a fatty acid derivative is filtered to obtain a filtration time, and the filtration time is used to determine the amount of the eluate eluted in the ink in which the resin or rubber material is immersed. You can ask for it. That is, prepare a plurality of inks (reference inks) containing a resin or rubber material and an eluent (emission material) such as fatty acid derivative that is acceptable for each ink, and have a filtration time shorter than the filtration time of the reference ink. It can be determined that the material is suitable for forming the ink flow path. The aforementioned threshold value and reference ink can be defined for each ink type and color.

In the method of the present invention, the eluate eluted (released) during immersion in water or ink contains an additive of resin or rubber material. Additives include, for example, stabilizers such as tin compounds, fatty acid calcium salts, phosphites, etc. to prevent deterioration due to heat during molding; glass, silica, metal to improve heat resistance, wear resistance, etc. Fillers such as powders; UV absorbers such as 2-hydroxybenzophenone, triazole, and acrylonitrile derivatives to prevent strength reduction due to UV; antimony oxide, barium metaborate, phosphates for improving flame retardancy Flame retardants such as: Plasticizers such as phthalic acid diester, dioctyl phthalate and butanol diester for adjusting processability; Antioxidants to prevent strength reduction due to air oxidation; Fatty acid glycerides such as stearic acid monoglyceride and palmitic acid monoglyceride Antistatic agent for preventing static electricity accumulation, etc .; Colorant; Release agent; Chlorine for polymerization Medium; fatty acid derivatives such as calcium stearate used as mold corrosion neutralizing agent; may include a vulcanization accelerator such as dithiocarbamate.

In another aspect of the present invention, the resin or rubber material used for the ink flow path is immersed in a large amount of heated water, such as water heated to 60 ° C., for a predetermined period, for example, 3 days. By repeating the operation a plurality of times (about 4 to 6 times), the fatty acid derivative and the like can be removed (purified).

A preferred embodiment of an ink jet recording apparatus to which the present invention is applied is shown in FIG. 1 includes four ink cartridges 61 each including black, yellow, magenta, cyan ink, and the like, a head unit 63 having a head 6 that ejects ink droplets onto a sheet 62, and an ink cartridge. 61, a carriage 64 provided with a head unit 63, a drive unit 65 that reciprocates the carriage 64 in a linear direction, a platen roller 66 that extends in the direction in which the carriage 64 reciprocates and is disposed to face the head 6, And a purge unit 67.

The driver unit 65 includes a carriage shaft 71, a guide plate 72, two pulleys 73 and 74, and an endless belt 75. Here, the carriage shaft 71 and the guide plate 72 extend in parallel with the platen roller 66 and support the carriage 64 so as to be slidable. The endless belt 75 is stretched between the pulleys 73 and 74. When the pulley 73 is rotated in the forward and reverse directions by the motor, the carriage 64 connected to the endless belt 75 is linearly moved along the carriage shaft 71 and the guide plate 72 along with the forward and reverse rotations of the pulley 73. Make a round trip.

The paper 62 is supplied from a paper cassette (not shown) connected to the ink jet recording apparatus 100, is sent between the head 6 and the platen roller 66, and scheduled printing is performed by ink droplets discharged from the head 6. And then discharged to the outside. Note that the paper feed function and the paper discharge function are not shown in FIG.

The purge unit 67 is installed on one side of the platen roller 66. The purge unit 67 includes a purge cap 81, a pump 82, a cam 83, and a waste ink reservoir 84. When the head unit 63 is placed at a position facing the purge cap 81, the purge cap 81 is raised by the cam 83 and contacts the nozzle surface of the head 6 to cover a plurality of nozzles formed in the head 6. . The ink in the head 6 is sucked by the pump 82, and thereby the thickened ink and bubbles in the head 6 are discharged. The sucked ink is stored in the waste ink reservoir 84. Further, a cap 85 is provided to prevent ink from drying, and covers the nozzles 15 (FIG. 2) of the head 6 provided on the carriage 64 when the carriage 64 returns to the reset position after printing.

FIG. 2 is a schematic diagram for explaining the head unit 63. The head unit 63 shown in FIG. 2 is upside down with respect to the state shown in FIG. As shown in FIG. 2, the head unit 63 is connected to a carriage 64 that moves along the paper 62, and is substantially a box shape with an open top in the state shown in FIG. 1. The head unit 63 has a cover plate 44 made of a metal plate. The cover plate 44 is fixed to the ink ejection surface side of the head unit 63 and covers the head 6. Further, the head unit 63 has a mount portion 2 to which the four ink cartridges 61 are detachably attached from the top in the state shown in FIG. Each of the ink supply paths 4 a, 4 b, 4 c, 4 d is connected to the respective ink discharge portion of each ink cartridge 61 and communicates with the bottom of the bottom plate 5 of the head unit 63. A rubber packing 47 is provided in each of the ink supply paths 4a, 4b, 4c, and 4d so as to be in close contact with the head 6.

The head 6 is composed of four blocks arranged parallel to each other. Each block of the head 6 is supported below the bottom plate 5 (upper side in FIG. 2). In the bottom plate 5, a plurality of recesses 9 a and 9 b are filled with an ultraviolet curable adhesive to connect the respective blocks of the head 6, and the recesses 9 a and 9 b are formed so as to penetrate the bottom plate 5. Yes.

There are a plurality of pressure chambers 16 in the head 6. FIG. 3 is a cross-sectional view showing one of the pressure chambers in the head 6. The plurality of nozzles 15 communicating with the respective pressure chambers 16 are provided in almost one row on one surface of the head 6. The head 6 includes a cavity plate 10 and a piezoelectric actuator 20. The cavity plate 10 has a manifold 12 connected to the ink supply paths 4a, 4b, 4c, and 4d, a narrow portion 16d, a pressure chamber 16, a passage hole 17, and a nozzle 15, and these communicate with each other. is doing. The controller 3 applies the drive pulse to the piezoelectric actuator 20 in synchronization with the clock signal. The driving pulse can be controlled by the technique disclosed in US Pat. Nos. 6312089, 6412923, or 6460959, for example. Further, the detailed structure of the ink jet recording apparatus and the control method of the head unit are disclosed in these US patents, and the contents of the disclosure of these US patents are incorporated herein by reference.

In the ink jet recording apparatus 100 shown in FIGS. 1 to 3, the ink flow paths are the cartridge 61, the ink supply paths 4 a, 4 b, 4 c, 4 d, the rubber packing 47, the head 6, and the cap 85. However, in general, the head 6 is made of a material other than resin or rubber material. Further, in an ink jet recording apparatus having another structure, for example, the ink flow path from the cartridge to the head as described in US 2003/0107625 A1 may be formed of a flexible tube formed of a resin or a rubber material. The resin or rubber material selected in the present invention can also be used for such a flexible tube. The disclosure content of US2003 / 0107625A1 is incorporated herein by reference.

The ink used in the inkjet recording apparatus to which the present invention is applied is not particularly limited, but the present invention is particularly effective when an inkjet ink containing 50% by weight or more of water is used. The ink-jet ink contains a coloring material, a wetting agent, an organic solvent that becomes a penetrating agent, and the like. In addition, if necessary, a pH adjuster, a sequestering agent, a viscosity adjuster, a surface tension adjuster, a wetting agent, a specific resistance adjuster, a film forming agent, an ultraviolet absorber, an antioxidant, a fading preventive, A rusting agent, a resin binder, a surfactant, a dye solubilizer, an antiseptic and fungicide may be contained. Further, when the ink jet recording apparatus is of a type that ejects ink by the action of thermal energy, the thermal physical properties (eg, specific heat, thermal expansion coefficient, thermal conductivity, etc.) may be adjusted. .

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.
< Reference Example 1 >
In order to produce the ink jet recording apparatus having the configuration shown in FIG. 1, each material shown in Table 1 was prepared as a material constituting the ink flow path. Each material was a test piece having dimensions of length: about 50 mm × width: about 10 mm × thickness: about 2 mm. Each test piece was immersed in distilled water in a sealed container, and the temperature of distilled water was adjusted to 60 ° C. using a thermostatic bath. The gas phase in the sealed container was air. The container was held at this temperature condition for 2 weeks. Two weeks later, the test piece was taken out from the container, and the fatty acid component (fatty acid derivative) was extracted from the liquid remaining in the container using diethyl ether. The fatty acid component in the obtained extract was derivatized with trimethylsilyl and then measured by GC-MS analysis. The results are shown in Table 1. In addition, the weight of the fatty acid derivative in the table was expressed as a weight ratio (ppm) of the eluted fatty acid derivative to the test piece.

＜参考例２＞
表２に示した材料を用いた以外は、参考例１と同様の条件で材料を蒸留水中に浸漬し、各材料から溶出した脂肪酸誘導体量を測定した。

< Reference Example 2 >
Except for using the materials shown in Table 2, the materials were immersed in distilled water under the same conditions as in Reference Example 1, and the amounts of fatty acid derivatives eluted from each material were measured.

＜参考例３＞
表３に示した材料を用いた以外は参考例１と同様の条件で材料を蒸留水中に浸漬し、各材料から溶出した脂肪酸誘導体量を測定した。なお、ここで用いた各材料は、参考例１と同種であるがグレードの異なるものである。

< Reference Example 3 >
The material was immersed in distilled water under the same conditions as in Reference Example 1 except that the materials shown in Table 3 were used, and the amount of fatty acid derivative eluted from each material was measured. The materials used here are the same as those in Reference Example 1 , but are of different grades.

＜参考例４＞
表４に示した材料を用いた以外は参考例１と同様の条件で材料を蒸留水中に浸漬し、各材料から溶出した脂肪酸誘導体量を測定した。なお、ここで用いた各材料は、参考例２と同種であるがグレードの異なるものである。

< Reference Example 4 >
The material was immersed in distilled water under the same conditions as in Reference Example 1 except that the materials shown in Table 4 were used, and the amount of fatty acid derivative eluted from each material was measured. The materials used here are the same as those in Reference Example 2 , but are of different grades.

＜インクジェット記録装置の製造＞
参考例１〜４の材料を用いて図２及び図３に示すようなインク流路を構成し、図１に示したインクジェット記録装置を組立てた。
＜評価＞
表５に示した各色インク組成を混合攪拌した後、０．２μｍのメンブランフィルターで濾過して各色インクを調製した。得られたインクを用いて、インク流路の材料として参考例１〜４の材料を用いて作製したインクジェット記録装置について、下記手順により噴射性を評価した。
（１）インクカートリッジをインクジェット記録装置に取り付け、インクを流路に導入する。
（２）テスト印字を行い、全ノズルからインクが噴射することを確認する。
（３）インクジェット記録装置を４０℃（湿度未調整）の環境下に２週間放置する。
（４）室温に戻した後、さらに１週間放置する。
（５）パージ及びテスト印字を繰り返す。

<Manufacture of inkjet recording apparatus>
The ink flow paths as shown in FIGS. 2 and 3 were formed using the materials of Reference Examples 1 to 4 , and the ink jet recording apparatus shown in FIG. 1 was assembled.
<Evaluation>
Each color ink composition shown in Table 5 was mixed and stirred, and then filtered through a 0.2 μm membrane filter to prepare each color ink. About the inkjet recording device produced using the material of the reference examples 1-4 as an ink flow path material using the obtained ink, jetting property was evaluated by the following procedure.
(1) The ink cartridge is attached to the ink jet recording apparatus, and the ink is introduced into the flow path.
(2) Perform test printing and confirm that ink is ejected from all nozzles.
(3) The ink jet recording apparatus is left in an environment of 40 ° C. (humidity unadjusted) for 2 weeks.
(4) After returning to room temperature, leave it for another week.
(5) Repeat purge and test printing.

The ink ejection at this time was evaluated according to the following criteria, and the results are shown in Table 6.
○: Discharge from all nozzles recovered after purging 5 times or less Δ: Discharge from all nozzles recovered after purging 6 to 10 times ×: From all nozzles even after 11 or more purges The discharge did not recover

＜実施例１＞
ブチルゴム、カーボンブラック及びシリコーンオイルを、ブチルゴム：カーボンブラック：シリコーンオイル＝１００：５０：２０の重量比で含むゴム材料の試験片を複数用意した。それらの試験片のうち、＃１〜＃３は、それぞれ、加硫促進剤として下記式（１）に示すようなジエチルジチオカルバミン酸亜鉛（ＥＺ）を表７に示すような割合（重量％）で含む。また、試験片＃４及び＃５は、それぞれ、加硫促進剤として下記式（２）に示すようなテトラメチルチウラウジスルフィド（ＴＴ）を表７に示すような割合（重量％）で含む。また、試験片＃６は、加硫促進剤としてテトラメチルチウラウジスルフィド（ＴＴ）及び下記式（３）に示すようなベンゾチアジルジスルフィド（ＤＭ）をそれぞれ表７に示すような割合（重量％）で含む。

<Example 1 >
A plurality of rubber material test pieces containing butyl rubber, carbon black and silicone oil in a weight ratio of butyl rubber: carbon black: silicone oil = 100: 50: 20 were prepared. Among these test pieces, # 1 to # 3 are each a proportion (wt%) of zinc diethyldithiocarbamate (EZ) as shown in the following formula (1) as a vulcanization accelerator as shown in Table 7. Including. Test pieces # 4 and # 5 each contain tetramethylthiulau disulfide (TT) as shown in the following formula (2) as a vulcanization accelerator in a proportion (% by weight) as shown in Table 7. In addition, test piece # 6 has tetramethylthiulau disulfide (TT) and benzothiazyl disulfide (DM) as shown in the following formula (3) as vulcanization accelerators in proportions (weight%) as shown in Table 7, respectively. ) Included.

＃１〜＃６の試験片を、それぞれ、密閉容器内のブラックインクに浸漬し、恒温槽を用いて６０℃に保温して２週間維持した。なお、密閉容器内の気相は空気であった。インク組成は、表５に記載のブラックインクの組成と同一である。その後、各ブラックインクを、孔径１３μｍの電鋳フィルターでろ過した。ろ過に要した時間は＃１〜＃６の各試験片を浸漬したブラックインクにより異なることがわかった。比較のために、いずれの試験片も加えないブラックインクのみを上記と同じ条件で保存して同じフィルタでろ過した時の時間（基準時間）を求めた。＃１〜＃６の各試験片を浸漬させたインクのろ過に要した時間の、基準時間に対する百分率を求め、表７に記した。フィルタでろ過された溶出物は、ＦＴ−ＩＲにより同定して、主に脂肪酸成分と前記式（１）〜（３）の加硫促進剤であることがわかった。また、ＦＴ−ＩＲの結果より、ろ過に要した時間が長いほど、インク中に溶出する溶出物量が多いことがわかった。このようにろ過時間は溶出物の量を表す基準となるので、ろ過時間を測定することで簡便な溶出物量の評価が可能となる。

The test pieces of # 1 to # 6 were each immersed in black ink in an airtight container, kept at 60 ° C. using a thermostatic bath, and maintained for 2 weeks. The gas phase in the sealed container was air. The ink composition is the same as that of the black ink described in Table 5. Thereafter, each black ink was filtered through an electroformed filter having a pore diameter of 13 μm. It was found that the time required for the filtration differs depending on the black ink in which the test pieces # 1 to # 6 were immersed. For comparison, the time (reference time) when only the black ink without any test piece was stored under the same conditions as described above and filtered through the same filter was determined. Table 7 shows the percentage of the time required for the filtration of the ink in which each of the test pieces # 1 to # 6 was immersed, with respect to the reference time. The eluate filtered through the filter was identified by FT-IR, and was found to be mainly a fatty acid component and a vulcanization accelerator of the above formulas (1) to (3). Further, from the results of FT-IR, it was found that the longer the time required for the filtration, the larger the amount of eluate eluted in the ink. As described above, the filtration time is a standard representing the amount of the eluate, and thus it is possible to easily evaluate the eluate amount by measuring the filtration time.

別途用意した＃１〜＃６の試験片を、上記と同様の浸漬条件で、表５に記載のイエロー、マゼンタ及びシアンのインク中にそれぞれ浸漬して、ろ過した。上記と同様にしてろ過に要した時間を、試験片を浸漬しなかったインクのろ過時間（基準時間）に対する百分率として、表７中に表した。以下の判断基準で各試験片を浸漬したインクを評価した。
◎：基準時間の１３０％未満のろ過時間を要したインク
○：基準時間の１３０％以上２００％未満のろ過時間を要したインク
△：基準時間の２００％以上４００％未満のろ過時間を要したインク
×：基準時間の４００％以上のろ過時間を要したインク
本実施例１の各材料を用いて、図２及び図３に示すようなインク流路を構成し、図１に示したインクジェット記録装置を組み立て、前記と同様な噴射性評価を行うと、本実施例１で２００％未満の評価が得られた材料でインク流路が構成されているインクジェット記録装置の方が、２００％以上の評価が得られた材料でインク流路が構成されているインクジェット記録装置よりも良好な噴射性評価が得られると予想されるという理由より、基準時間の２００％を超えない範囲のインクは良好といえる。良好な評価を満たすインクはインクの色によっても異なることがわかる。また、表７の結果より、加硫促進剤としてジエチルジチオカルバミン酸亜鉛（ＥＺ）を含んでいる方が、他の加硫促進剤に比べて溶出物の溶出量が多いこともわかる。したがって、ジエチルジチオカルバミン酸亜鉛（ＥＺ）を含有しているか否かがインク流路の材料を選択するための基準のひとつとなり得る。いずれにしても、上記実施例及び参考例の結果に基づいて、インクのろ過時間、すなわち、溶出量を所定量に低減する材料を選定することによって、インクジェットヘッドのノズル等の詰まりを抑制又は防止できることがわかる。

Separately prepared test pieces of # 1 to # 6 were immersed in the yellow, magenta and cyan inks listed in Table 5 under the same immersion conditions as above, and filtered. The time required for the filtration in the same manner as described above is shown in Table 7 as a percentage with respect to the filtration time (reference time) of the ink in which the test piece was not immersed. The ink in which each test piece was immersed was evaluated according to the following criteria.
A: Ink that required a filtration time of 130% or less of the reference time B: Ink that required a filtration time of 130% or more and less than 200% of the reference time Δ: A filtration time of 200% or more and less than 400% of the reference time Ink x: ink that required a filtration time of 400% or more of the reference time The ink flow path as shown in FIGS. 2 and 3 was formed using each material of Example 1 , and the ink jet recording shown in FIG. When the apparatus is assembled and the jettability evaluation is performed in the same manner as described above, the ink jet recording apparatus in which the ink flow path is made of a material that is evaluated to be less than 200% in the first embodiment is 200% or more. Ink in a range not exceeding 200% of the reference time is good because it is expected that a better jetting evaluation can be obtained than an ink jet recording apparatus in which an ink flow path is configured with an evaluated material. Obtain. It can be seen that ink that satisfies a good evaluation varies depending on the color of the ink. In addition, it can be seen from the results of Table 7 that the amount of eluate eluted is greater when zinc diethyldithiocarbamate (EZ) is contained as a vulcanization accelerator than other vulcanization accelerators. Therefore, whether or not zinc diethyldithiocarbamate (EZ) is contained can be one of the criteria for selecting the material for the ink flow path. In any case, clogging of the nozzles of the inkjet head, etc. is suppressed or prevented by selecting a material that reduces the ink filtration time, that is, the amount of elution, to a predetermined amount based on the results of the above-described examples and reference examples. I understand that I can do it.

According to the present invention, it is possible to select a simple method for an ink flow path material optimum for an actual use situation without examining the components and compositions of each material constituting the ink flow path of the ink jet recording apparatus. By using the material selected by such a method, foreign substances such as fatty acid derivatives eluted in the ink filled in the ink jet recording apparatus can be reduced. Therefore, it is possible to provide an ink jet recording apparatus capable of obtaining stable, high reliability, and high image quality.

It is a schematic diagram showing one embodiment of an inkjet recording device. It is a schematic diagram for demonstrating a head unit. It is sectional drawing which shows one of the pressure chambers in a head.

Explanation of symbols

100 Inkjet recording device 61 Ink cartridge 62 Paper 63 Head unit 64 Carriage 65 Drive unit 66 Platen roller 67 Purge unit

Claims (5)

Immersing a resin or rubber material in a sealed container for a predetermined period of time in a heated ink obtained by heating an ink used in an ink jet recording apparatus;
Filtering the ink after dipping the resin or rubber material to determine the filtration time;
Determining whether the resin or rubber material is suitable as a material to be used for at least part of the ink flow path of the ink jet recording apparatus based on the filtration time;
A method for selecting a resin or rubber material used in at least a part of an ink flow path of an ink jet recording apparatus. The sorting method according to claim 1, wherein the resin or rubber material is immersed in a heated ink heated to 60 ° C. for 2 weeks in an airtight container with the resin or rubber material. The ink used in the ink jet recording apparatus without being immersed in the resin or rubber material is heated in a sealed container and held for a predetermined period, and then the ink is filtered to obtain a reference filtration time. The reference filtration time and the resin or rubber are The sorting method according to claim 1 or 2, wherein the filtration time when the material is immersed in ink is compared. The sorting method according to claim 3, wherein the ink is heated to 60 ° C. in a sealed container and held for 2 weeks. The sorting method according to claim 1, wherein the ink flow path includes at least one of an ink cartridge, an ink supply path, rubber packing, a head, a cap, and an ink supply tube .

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