JPS59182863A - Apparatus for purification of dye - Google Patents

Abstract

PURPOSE:To carry out the continuous and automatic mass-production of purified dye having high quality and suitable as the ink for writing utensils, etc., by using a means for the preparation of a dye solution in combination with a means for detecting the concentration of inorganic salt in said solution, and a means to control the salt concentration according to the output signal of the detecting means. CONSTITUTION:Dye powder 22 is fed from the dye reservoir 21 to the mixing tank 24, and the prepared dye solution is supplied through the supply tank 31 to the purification zone 41 furnished with a detector 46 to detect the concentration of inorganic salt by ion chromatography, etc. When the concentration of the salt detected by the detector 46 is higher than a preset level (preferably <=5wt%), the solution is passed through the salt-rejection filter 43 by operating the circulation pump 48 to obtain the purified dye. The excess salt is discharged to the waste tank 44.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a dye purification device, and particularly to an ink chef 1-
Recording fluid (generally called ink) suitable for recording and writing instruments, etc.
This invention relates to a dye purification device that continuously supplies purified dye suitable for the preparation of dyes.

[Prior Art] Conventionally, inkjet recording methods in which recording is performed by ejecting ink in a recording head from an ejection orifice using vibrations caused by a piezoelectric vibrator, etc. Ink used in the recording method include various dyes and pigments mixed with water or other materials. It is known to be dissolved or dispersed in a liquid medium consisting of an organic solvent6.
It is also known that similar inks are used in writing instruments such as pens and fountain pens.

An example of a general basic composition of such an ink is one consisting of three main components: a water-soluble dye, water as its solvent, and glycols as an anti-drying agent.

Here, the water-soluble dye usually contains a large amount of inorganic salts such as sodium chloride and sodium chloride. These S machine salts are not only those produced as by-products during the dye synthesis reaction process, but also those that are actively added as salting-out agents, diluents, or leveling agents.

When recording ink is prepared using dyes containing such inorganic salts, the following disadvantages occur. That is,
Inorganic salts reduce the stability of dye dissolution in the ink, leading to aggregation and precipitation of the dye. In addition, in inkjet recording heads and writing instruments, if the ink evaporates near the ejection orifice and the liquid composition changes, this causes precipitation of inorganic salts. All of these are the most likely causes of clogging of the discharge orifice, which should be avoided.

Therefore, in order to eliminate such adverse effects, eight methods are used to control the concentration of inorganic salts within a predetermined range (for -n, the concentration of inorganic salts in the ink should be 0.5% or less). There is. This is essential when a general commercially available dye containing the inorganic salt M as an impurity is used for preparing an inkjet recording ink or a writing instrument ink.

[Purpose] In view of these points, the purpose of the unreleased UL is to control the fu11) and mechanical salts contained in the ink when preparing the ink, thereby improving the quality of inkjet recording materials and Js.
A purified dye O'I solution suitable for preparing ink for marking utensils was prepared using X! l! An object of the present invention is to provide a dye purification device that can be continuously supplied.

[Example] The present invention will now be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the apparatus of the present invention.

Here, 2I is a dye supply unit that stores the dye powder 22, and supplies the dye powder 22 to the mixing tank 24 via the dye/help 23. Further, pure water is supplied to the mixture 4pJ24 through a pure water supply pipe 28 in which a pure water valve 25 is inserted.

In this mixing tank 24, the supplied dye powder 22 and pure water are mixed and dissolved by a mixing tank agitator 27 to produce an aqueous dye solution. The amount of the aqueous dye solution stored in the mixing tank 24 is detected by a mixing tank liquid portion detector 28 . The aqueous dye solution obtained in the mixing tank contains particles of dye powder that were not dissolved in the pure water, and these are removed by the filter 29. This filter 29 has
Ordinary filter paper or Fluorobor (trade name) can be used. The aqueous dye solution from which particles and the like have been removed by passing through the filter 29 is supplied to the supply tank 31 .

The aqueous dye solution supplied to the supply tank 31 is passed through the supply valve 32.
is stored in the supply tank 31 as long as it is in the closed state. Here, this supply tank 31 has a 3'7-3 for controlling the liquid level height.
3 is installed to suppress the temperature of the dye aqueous solution stored in the supply tank to below a certain level.

Next, 41 is a purification section that removes inorganic salts from the aqueous dye solution. In this purification section 41, 42 is a salt reduction tank, 43
is a salt reduction filter, and 44 is a salt removal tank. Salt reduction tank 4
2, one volume drop of dye water is supplied via the supply valve 32. The supplied aqueous dye solution is stirred by an IL&JM tank stirrer 45 to homogenize the aqueous solution, and an inorganic salt concentration detector 46 detects the concentration of inorganic salts in the aqueous solution. This concentration detection is performed, for example, by ion chromatography. Further, a dye concentration detector 47 detects the dye concentration in the aqueous solution. This concentration detection is performed, for example, by spectrophotometry. As described below, when it is detected that the concentration of inorganic salts is a predetermined value (for example, 5IT (volume %) or more with respect to the dye),
The circulation pump 48 is operated to remove the dye aqueous solution in the salt reduction tank.
4 is circulated through the ibin1j4 filter 43. This reduction filter is, for example, an ultrafiltration filter.

i! ! 4 Use an fsL transparent filter, etc. By passing through the salt-reducing filter 43, aqueous salts such as sodium chloride and sodium sulfate contained in the aqueous dye solution are filtered out from the aqueous dye solution, and the salt is removed from the salt removal tank 44.
is discharged. In this way, a portion of the water, which is a solvent for the dye, is discharged into the salt tank 44 along with the inorganic salts. Therefore, in addition to replenishing the dye aqueous solution with this discharged water, the salt-reducing tank 42 is connected to the salt-reducing tank 42 via a pure water valve 48 so that a dye aqueous solution with a desired concentration is obtained in the salt-reducing tank 42.
Supply pure water to 2.

In this way, an aqueous dye solution having an inorganic salt concentration and a dye concentration within a predetermined range is obtained in the salt reduction tank 42. Note that the amount of dye aqueous solution in the salt reduction tank 42 is detected by a salt reduction tank liquid amount detector 50.

The aqueous dye solution purified as described above (salt reduction) is discharged into the storage tank 52 via the storage valve 51 and stored in the storage tank.

FIG. 2 shows the control system of the apparatus shown in FIG. Here, 6
Reference numeral 1 denotes a controller, which controls the drive of each part. 62
is a read-only memory (ROM) in which a control program such as the operating procedure shown in FIG. 3 is stored. 83 is a random access memory (RAM) in which various takes are temporarily stored.

In this example, analog signals are output from the inorganic salt concentration detector 46 and the dye concentration detector 47, and each A/
After being converted into a digital number 1 via the D converters 64 and 65, it is supplied to the controller 61 via a large-power 4-FF circuit 66. On the other hand, digital signals are output from the mixing tank liquid level detector 28 and the salt tank liquid level detector 50, respectively, and are supplied to the controller 61 via the input buffer circuit 66.

67 to 74 are the aforementioned valves 23.2'5, 48.3
2 and 51, the stirrers 27 and 45, and the circulation pump 48 by one stroke, and are controlled to be turned on and off by a drive signal supplied from the controller 61 via the output buffer circuit 75.

81 and 82 are a dye concentration range setting switch and an inorganic salt concentration range setting switch, respectively, and a signal corresponding to the J seismic intensity range determined by JJ is sent to the console input/output 42.
The signal is supplied to the controller via the 27 circuit 83. Reference numerals 84 and 85 are a dye concentration indicator and an inorganic salts concentration indicator, respectively, which display the dye concentration value and a salt-free concentration value in the aqueous dye solution being purified. Therefore, the operator of this apparatus can easily know the quality of the aqueous dye solution being produced.

The values set for the dye concentration range and inorganic salt concentration range by switches 81 and 82 are temporarily stored in RAM 83. Inorganic salt concentration detector 46 and dye concentration detector 4
The detected concentration values of inorganic salts and dyes in the aqueous dye solution being purified by 7 are determined by the comparison unit 1311 of the controller.
is compared with a set value, and based on the comparison result, the drive of each load of the circulation pump 48'4 is controlled as described later.

FIG. 3 shows the operation flow of the apparatus shown in FIG. 1. In the figure, step 5TI-9T4 is a step for maintaining the dye aqueous solution in the mixing tank 24 at a constant amount. That is, the procedure STI
Now, from the output of the mixing tank liquid level detector on the 2nd day, it is determined whether the liquid level of the dye aqueous solution in the mixing tank 24 is 1-1 & higher than the low position that defines the predetermined setting range. To detect. If it is below that low position, f, llTl S
Proceed to T2, and if not, proceed to step ST3.

At hand 111ft ST 2, the dye valve 23 and pure water valve 25 are opened, and predetermined amounts of dye powder and pure water are respectively put into the mixing tank 28. In the mixing tank 24, since the stirrer 27 is always in operation, the dye powder introduced therein is dissolved in pure water and the dye is quietly mixed into water. In step ST3, it is detected based on the output of the liquid amount detector 28 whether or not the liquid level in the mixing tank 24 is above a high position that defines the setting range. If the position is higher than 1°ν1, proceed to step ST4, otherwise proceed to step ST4.
Proceed to ST5. In step ST4, the dye valve 23 and pure water valve 25 in the closed state ji are closed to stop the supply of dye powder and pure water.

In step ST5, the dye concentration value in the aqueous dye solution in the salt reduction tank 42 detected by the dye a degree detector 47 is displayed on the table 84. In step ST6, the inorganic salt concentration value also detected by the inorganic class M concentration detector 46 is displayed on the display 85.

1'', mn ST 7 determines whether the dye concentration detected by the detector 47 is within the dye concentration range set by the swifter 81. It is determined that it is within the immersion range. If so, proceed to step ST8; otherwise, proceed to step ST9. In step ST8, the concentration of the inorganic class 1C detected by the detector 46 is within the range of the value set by the switch 82. If it is determined that it is within the set range, the process proceeds to step 5TIO, and if not, the process proceeds to step ST9.

In step ST9, the salt-reducing tank 4 detected by the detector 50
It is determined whether the liquid level in 2 is older than the high position that defines the setting range. If it is below that high position, step 5T1
If not, proceed to step 5T12. In step 5TII, the supply valve 32 and the pure water valve 49
The aqueous dye solution and pure water are supplied into the salt reduction tank 42 by controlling opening and closing. As a result, the dye concentration in the aqueous dye solution in the salt reduction tank 42 is adjusted to fall within the range set by the switch 81 as described above. After this, proceed to step 5TI3. - On the other hand, in step 5T12, the supply valve 32 and the pure water/help 49 are closed.

At f order 5T13, the circulation pump 48 is operated to reduce I.
The dye aqueous solution in 4f11142 is circulated through the salt-reducing filter 43 to remove inorganic salts from the dye aqueous solution.

”-as mentioned, dye concentration and no! ! If the IIM level is outside the setting range, step 5TII and step 5T1
3 or 1 - Repeat the routine through step 5T12 and step 5T13 to bring the dye concentration and inorganic salt concentration within the set range. After the image density falls within the set range, proceed to step 5TIO.

In the T=order 5TIO, it is determined whether the liquid mi in the salt reduction tank 42 detected by the detector 50 is 1- lower than the lower position defining the 61-regular range. If it is lower than that position, proceed to step 5TI4; otherwise, proceed to step 5TI4.
Proceed to T15. Hair 11 [In 4ST14, circulation pump 4
8] to open the storage valve 51. As a result, a predetermined amount of purified dye aqueous solution obtained in the reduced-Imum 4P442 is supplied to the 16° storage tank 52.

In Toboro ST1'5, the closing operation of the storage/help 51 and the supply help 32. The pure water valve 48 is opened to end the supply to the storage tank 52, and the amount of dye aqueous solution in the salt reduction tank 42 is increased so that the liquid level is within the set range.

After this, repeat the routine that goes through the above-mentioned hand+1iT11, 5T13 or steps 5T12, 5T13 again,
In the salt reduction tank 42, an aqueous dye solution having a predetermined dye concentration and an inorganic salt concentration within a predetermined range is obtained. After this, the process proceeds to step 5T14 described above.

As described above, in this embodiment, the aqueous dye solution is purified in the purification section 41 in fixed amounts.

[Effect] As explained above, according to the present invention, when producing a dye solution, the concentration of 911-choki salts contained in the dye solution is detected, and based on the detection result, That is, since the concentration of inorganic salts is adjusted, ink for inkjet recording, ink for writing instruments, etc.;
A purified dye solution suitable for im production can be produced.

Further, according to the present invention, it is possible to continuously and automatically reduce the dye solution to %lj5m, making it suitable for large-scale production of high-quality ink.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the device according to the present invention, FIG. 2 is a block diagram showing the control section of the device shown in FIG. 1, and FIG. 3 shows the operation of the device shown in FIG. 1. It is a flowchart. 21... Dye supply unit, 22... Dye powder, 23... Dye valve, 24... Mixing tank, 25... Pure water valve, 26... Pure water supply pipe, 27... Preparation tank agitator 28...Preparation tank liquid part: detector, 29...filtration filter, 31...supply tank. 32... Supply valve, 33... Valve, 41... Purification section, 42... Salt reduction tank, 43... Salt reduction filter, 44... Salt removal tank, 45... Salt reduction Horizontal stirrer, 46...Inorganic salt concentration detector, 47...Dye concentration detector, 48...Circulation pump, 49...Pure water valve, 50...Salt reduction tank liquid level detector. 51...Storage valve, 52...Storage tank, 61...Controller, 62...Read only memory (ROM), 63...
Random Access Memory (RAM). 64.65...A/D converter, 68...Input 4-fufa circuit. 67-74...Drive circuit, 75...Output buffer circuit, 81...Dye concentration range setting switch, 82...Inorganic salt concentration range setting switch, 83...Console input/output 4227 circuit, 84...Dye concentration indicator, 85...Inorganic salt concentration indicator, ell...Comparison section.

Claims (1)

[Claims] Means for producing a dye solution, and no residue in said solution! ! 1. A dye purification apparatus, comprising: a concentration detection means for the i-class concentration; and an inorganic salt concentration control means for controlling the concentration of the salts based on the detection output.