JPS59199768A - Dye purification equipment - Google Patents

Abstract

PURPOSE:To obtain a purified high-quality dye solution suitable for preparing ink-jet recording ink, etc., by the chromatographic treatment of a dye solution to remove the inorganic salts contained. CONSTITUTION:A dye powder 22 and pure water are fed to the preparation tank 24, being mixed by an agitator to prepare an aqueous dye solution. Subsequently, this solution is filtered to remove contaminated particles, etc., being fed to the feed tank 31 followed by feeding it to the on-off units 43 in the purification section 41 for removing the inorganic salts contained, where a control operation is performed to determine whether the aqueous dye solution, pure water, and secondary solution should be fed to the salt-reducing filter units 44. If fed to the units 44, said dye solution and secondary solution are subjected to chromatography to eliminate the inorganic salts contained. When the concentration of the above salts reaches a specified value, said solutions are discharged into the storage tank 56 through the control of the on-off valves 45.

Description

Detailed Description of the Invention [Technical Field] The present invention relates to a dye purification device, and particularly to a dye purification device that continuously supplies purified dye suitable for preparing recording liquid (generally referred to as ink) suitable for inkjet recording, writing instruments, etc. Regarding.

[Prior Art] Conventionally, inks used in the Infusiera I recording method, in which recording is performed by ejecting ink in a recording head from an ejection orifice using vibrations caused by a piezo vibrator, have been made by mixing various dyes and pigments with water or other materials. It is known that it is dissolved or dispersed in a liquid medium consisting of an organic solvent. It is also known that similar inks are used in writing instruments such as felt 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 sulfate. These inorganic 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, ink evaporates near the ejection orifice, causing a change in liquid composition and precipitation of inorganic salts. All of these causes clogging of the discharge orifice that should be the most important.

Therefore, in order to eliminate such adverse effects, it is necessary to control the concentration of inorganic salts within a predetermined range (generally 0.5% by weight or less in the ink) during ink production. This is essential when a commercially available dye containing inorganic salts as an impurity is used to prepare an inkjet recording ink or a writing instrument ink.

[Objective] In view of these points, the object of the present invention is to remove the inorganic salts contained in the ink when preparing the ink, thereby making it suitable for preparing inkjet recording ink, ink for writing instruments, etc. It is an object of the present invention to provide a dye purification device capable of continuously supplying a purified dye solution.

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

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

Here, 21 is a dye supply section that stores dye powder 22, and supplies the dye powder 22 to a mixing tank 24 via a dye valve 23. In addition, a pure water valve 2 is provided in the mixing tank 24.
Pure water is supplied through a pure water supply pipe 26 with a pipe 5 inserted therein.

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 amount 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 Fluoropore (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 supplied to the purification section described below via the supply pipe 32. Here, the supply tank 31 is provided with a valve 33 for controlling the liquid level to suppress the amount of dye aqueous oil stored in the supply tank to a certain amount or less.

Next, 41 is a purification section that removes inorganic salts from the aqueous dye solution, and includes a plurality of salt reduction treatment units 42 (42-1 to 42-1).
2-N). In the salt reduction processing unit 42, 4
3 (43-1 to 43-N) are supply valve opening/closing parts, 44 (
44-1 to 44-N) are salt reduction filter parts, and 45 (
45-1 to 45-N) are discharge valve opening/closing parts.

The supply valve opening/closing section 43 includes a dye aqueous solution supply pipe 47 (4
7-1~47-N), pure water supply pipe 4f ((4B-1~
4B-N) and secondary solution supply pipe 48 (48-1 to 48
-N) respectively. Supply tank 31 for dye aqueous solution
The water is supplied to the opening/closing section 43 through the supply pipes 32 and 47 in sequence, and pure water is supplied through the supply pipes 26 and 46 in sequence.

Further, a secondary solution, which will be described later, is supplied from the secondary solution storage tank section 51 to the supply valve opening/closing section 4 through supply pipes 52 and 48 in sequence.
Supply to 3.

The supply valve opening/closing section 43 controls whether or not the supplied aqueous dye solution, pure water, and secondary solution are supplied to the salt reduction filter section 44 .

In the salt-reducing filter section 44, the dye aqueous solution supplied from the supply valve opening/closing section 43 and 2
Next, exclude inorganic salts from the solution.

By controlling the discharge valve opening/closing section 45, the concentration of inorganic salts is reduced to a predetermined value (for example, 5% for the dye) through such (salt reduction) purification.
The dye aqueous solution that has become less than
-1 to 55-N) to the storage tank 56. Further, the aqueous solution discharged from the filter section 44 is transferred to the inorganic salt solution discharge section 58 or the discharge pipe 59 (59-N) via the discharge pipes 57 (57-1 to 57-N), depending on the component concentration.
1 to 59-N).

One end of this discharge pipe 59 is communicated with the suction port of a circulation pump 60, and the aqueous dye solution discharged into the discharge pipe 58 is passed through the discharge pipe 61 communicated with the discharge port of the pump 60 into two. The next solution is fed under pressure to the solution storage tank 51.

In this way, the dye aqueous solution refluxed from the discharge side of the purification section 41 is supplied as a secondary solution to the purification section 41 again, and (
Salt reduction) purification.

Next, 71 is a control section that controls the drive of each section, and 72 is an operation section that includes various display sections, drive switches, and the like.

Note that 73 and 74 are discharge valves disposed in the storage tank 56 and the discharge tank 58, respectively.
3 and 74 to discharge the aqueous dye solution and the inorganic salt concentration.

FIG. 2 shows the configuration of the salt reduction treatment unit 42 shown in FIG. 1.

In the figure, the first supply valve 431 in the supply valve opening/closing section 43 is controlled to open and close to control the supply of pure water to the salt reduction filter section 44 via the supply pipe 46.

Similarly, the second supply valve 432 and the third supply valve 43
2 to the salt-reducing filter section 44 by controlling the opening and closing of 3.
Control the supply of the next solution and the aqueous dye solution.

Next, the salt-reducing filter section 44 separates inorganic salts from the dye aqueous solution by chromatography. That is, an aqueous dye solution is supplied to one end of the chromatography column 441 from the supply valve opening/closing section 43. While the supplied aqueous dye solution descends within the column 441, each component in the aqueous solution is separated. Through such a developing operation (chromatography),
The components with the weakest adsorption properties flow out first. Therefore,
By detecting the component concentration of the effluent solution, it is possible to extract only the part of the effluent solution in which the inorganic salts are below a predetermined concentration before the dye is dissolved in water, based on the detection result.

Inorganic salt concentration detector 442 and dye concentration detector 443
is for detecting the concentration of inorganic salts and dye in the solution flowing out from the column 441, and is disposed in the flowing liquid passage 444 at the lower end of the chromatography column 441. As a method of detecting each component, there are a method of measuring conductivity, a method of using ionic current, a method of measuring spectrophotointensity, etc., and any of them may be used.

A dye solution is supplied to the chromatography column 441 in fixed amounts for purification (salt reduction).For this purpose, a liquid level position detector 445 is installed at the upper end of the column. The supply of the aqueous solution from the supply valve opening/closing section 43 is controlled based on the detection result.

Here, the stationary phase filled in the column 441 generally includes ion exchange resins, chelate resins, etc.
In this example, an ion retardation resin, such as Retardion IIA, is used.
-8 (trade name: manufactured by Dow Chemical Company) is used. Ion retardation resins do not require regeneration agents, can be regenerated with pure water, and are nearly neutral, so they are advantageous for desalting substances that are unstable to acids and alkalis.

FIG. 3 shows an outflow curve in which the concentration of each component of the outflow solution from the chromatography column 441 is plotted against the time axis, that is, the fractionation characteristics. As shown, the dye concentration (curve line) peaks between hours 11 and 72, and the inorganic salt concentration (curve ■) peaks between hours 13 and 74. In this example, based on such classification characteristics, the inorganic class M concentration detector 442
Based on the detection value of the dye concentration detector 443, the effluent solution from the chromatography column 441 is fractionated and extracted as follows.

That is, when the dye concentration of the effluent solution is equal to or higher than the predetermined value C2 (effective dye concentration) and the inorganic salt concentration is less than the predetermined value C3 (allowable inorganic salt concentration) (between times 11 and 72), the effluent solution is transferred to the storage tank. Leads to 56. However, after the inorganic class concentration exceeds the value C3 and the dye concentration falls below the value C21ii-, the effluent solution is led to the inorganic salt solution discharge tank 58. Also, during the period from when the inorganic salt concentration becomes C3 or higher until the dye concentration decreases to C2 or lower (between times 72 and 73).
The effluent solution is refluxed to the secondary solution storage tank 51.

Referring again to FIG. 2, the discharge valve opening/closing section 45 separates the outflow solution as described above, and the outflow passage 444
is branched into three prongs, and each branch pipe and discharge pipe 57, 59 and 55 are connected to the first pipe. Second and third discharge valve 4
51, 452 and 453. With this configuration, by opening the first discharge valve 451, the effluent solution can be discharged to the inorganic salt solution discharge tank 58, and similarly, by opening the second and third discharge valves 452 and 453, the effluent solution can be discharged into the inorganic salt solution discharge tank 58. Next solution storage tank 51
and can lead to storage $1i''15fll.

FIG. 4 shows the control system of the apparatus shown in FIG. here 10
Reference numeral 1 denotes a controller, which controls the drive of each part. 10
Reference numeral 2 denotes a read-only memory (ROM), which stores a control program such as the operating procedure shown in FIG. A random access memory (RAM) 103 temporarily stores various data.

Reference numeral 104 denotes various switches disposed on the operation unit 72, and sends various command signals to the controller 101 via an input/output 71277 circuit 105. Reference numeral 108 denotes a display disposed in the operation unit 72, and reference numeral 107 denotes a drive circuit that controls the display of the display 106 based on a sliding signal from the controller 101.

In this example, analog signals are output from the inorganic salt concentration detector 442 and the dye concentration detector 443, and are converted into digital signals via A/D converters 111 and 112, respectively, and then sent to the input buffer circuit 113. The signal is supplied to the controller 101 via the controller 101. On the other hand, the liquid level position detector 445 outputs a digital signal, and the input 4777 circuit 113
The signal is supplied to the controller 101 via.

121 to 126 are the aforementioned valves 431, 432, 4.
33.

This is a drive circuit for opening and closing 451, 452, and 453, respectively, and is controlled to be turned on or off by a drive signal supplied from the controller 101 via the output buffer circuit 127.

In addition, since the configurations of the salt reduction processing units 42-1 to 42-N are the same, only unit h 42-1 is shown in the figure, and the other units 42-2 to 42-N are omitted. be.

FIG. 5 shows the operation of each processing unit in this embodiment configured as described above.

In the figure, when a start command is received from the operation unit 72 in step STI, the program switch is set to OFF in step ST2. Next, in step ST3, the second and third supply valves 432 and 433 are opened to start supplying the dye aqueous solution in the supply tank 31 and the secondary solution in the secondary solution storage tank 51 into the chromatography column 441. This supply operation continues until the liquid level in the column 441 reaches the highest position H (see FIG. 2) according to the output of the liquid level position detector 445 in step ST4. When the liquid level height H reaches the maximum position, that is, when a predetermined amount of aqueous solution has been supplied to the column, step ST
5, both valves 432 and 433 are closed.

Next, in step 5Tf, the first exhaust valve 45
1 is opened, and the effluent solution from the chromatography column 441 begins to be discharged to the inorganic salt droplet discharge tank 58.

In step ST7, it is determined whether the liquid level in the column is at the lowest position (see FIG. 2). Immediately after supplying the dye aqueous solution and secondary solution,
The liquid level is above the lowest position, so select "NO"
It is determined that this is the case, and the process proceeds to step ST8. In step ST8, the first supply knob 431 is closed, and the process proceeds to step 5TIO. Here, as described above, immediately after the dye aqueous solution and the secondary solution are supplied and the developing operation is started in the column 441, the concentration of each component of the effluent solution is shown between time 0 and TI in FIG. in a state.

Therefore, in step 5TIO, the dye concentration detector 4
The density value detected by 43 is equal to or greater than the effective dye density value C2.
The judgment as to whether or not it is 2 is "NO", and step 5
Proceed to T11. Furthermore, in step 5T11, it is determined whether or not the concentration value detected by the inorganic salt concentration detector 442 is equal to or higher than the inorganic salt concentration value C1.
”, and the process proceeds to step 5T12. Step 5T1
At step 2, it is determined whether the program switch is in the on state. In the first loop, since it is in the off state, the determination is "NO" and the process returns to step ST7. Steps ST7→ST8→5 like this
The loop of TIO → 5T11 → 5T12 is step 5T
This process is repeated until rYES J is determined in IO.

In addition, in step ST7, when it is determined that rYEsJ, the process proceeds to step ST9, and the first supply pulp 4
31 is opened, and pure water is supplied to the column 441. Therefore, in such a case, steps ST7→ST9→5T
A loop of IO→5T11→5T12 is executed.

In step 5TIO, when the dye concentration value of the droplet flowing out from the column 441 becomes equal to or higher than the effective dye concentration value C2 (time TI in FIG. 3), the process proceeds to step 5T13. In step 5T13, it is determined whether the inorganic salt concentration (1t4) detected by the inorganic salt concentration detector 442 is greater than or equal to the allowable inorganic salt j agricultural value C3 - I ni.

Here, by the development operation of the chromatography column 441, inorganic 1! The dye aqueous solution that has been separated out flows out first (
(See Figure 3 between T1 and T2 in 11 yen), Step 5TI3
Then, the determination is "NO" and the process proceeds to step 5T14. In step 5TI4, the first discharge valve 451 is closed, and in step 5T15, the third discharge valve 453 is opened, and the chromatography column 441 is closed.
The effluent solution is discharged through a discharge pipe 55 to a storage tank 56. Next, in step 5T16, the program switch is turned on, and the process returns to step ST7. Steps like this ST7→ST8→5TIO→5TI3→5T1
4→5T15→s'rte or step ST7→ST
9→5T10→5T13→5T14→5T15→5T1
8 loops are repeated, and an aqueous dye solution purified to have an inorganic salt concentration of 0.3 or less is obtained in the storage tank 56. Such a loop executes rYEs in step 5T13.
This continues until it is determined as J.

As shown in FIG. 3, the inorganic salts begin to flow out and the inorganic salt concentration of the effluent solution increases, and when the value reaches the allowable inorganic salt concentration value 03 or more (time T2 in FIG. 3), steps 5T13 to The process proceeds to step 5T17, where the third exhaust valve 453 is closed, and the second exhaust valve 452 is opened at step 5T18. As a result, the outflow solution is stopped from being discharged to the storage tank 5B and is discharged to the discharge pipe 59. here,
In this example, when the circulation pump 60 is driven in synchronization with the opening operation of the pulp 452, the effluent solution is discharged from the discharge pipe 59.8.
1 to the secondary solution storage tank 51. This refluxing operation of the effluent solution is performed in step 5TIO by "NO
” until it is determined! #Continued. The secondary solution recovered in this way will be purified again to reduce salt. Next, when the dye concentration of the effluent solution decreases and its value falls below the effective dye concentration value C2 (time T3 in Figure 3), step 5
The TIO determines “NO” and the process proceeds to step 5T11.
Proceed to. Now, since inorganic salts are continuing to flow out, it is determined in step 5TII that "rYEs" and the process proceeds to step 5T19, where the second discharge valve 452 is closed, and further, in step 5T20, the first discharge valve 4 is closed.
51 opening operation is performed. As a result, the effluent solution stops flowing back to the secondary solution storage tank 51 and begins to be discharged to the inorganic salt solution storage tank 58 via the discharge pipe 58. This draining operation is continued until the inorganic salt concentration of the effluent solution falls below the cleaning inorganic salt concentration value C1.

'When the M salt concentration falls below the value C1 (Fig. 3 Time T4
), the determination in step 5TII is "NO" and the process proceeds to step 5TI2. Here, since the program switch is set to ON in step 5Tl13 as described above, rYE is set in step 5T12.
sj, the process proceeds to step 5T21, the first discharge valve 451 is closed, and the discharge of the outflow solution to the discharge tank 58 is completed.

Next, in step 5T22, the supply valve 431 is closed, and the supply of pure water to the chromatography column 441 is stopped. That is, in this example, the first supply valve 431 is controlled to open and close so that the liquid level of the aqueous solution in the chromatography column 441 is always at the lowest position (see FIG. 2), and pure water is supplied (Stella 7 "ST8, 5T9). This pure water washes (regenerates) the stationary phase inside the chromatography column. As mentioned above, when the inorganic salt concentration of the effluent solution falls below the washing inorganic salt concentration C1, the washing is carried out. (reproduction)
It is determined that this has occurred, and the supply of pure water is stopped.

After executing step 5T22, step STI is executed again.
Return to and wait for the start command.

One (salt reduction) purification operation is completed as described above. In addition, in this embodiment, each processing unit) 42-
Although the operations 1 to 42-N are executed synchronously, they are not limited to this, and of course may be executed sequentially, for example.

Further, in this embodiment, the collected secondary solution is purified in each processing unit 42, but a separate processing unit exclusively for the secondary solution may be provided to perform the purification.

[Effects] As explained above, according to the present invention, when producing a dye solution, the dye is purified by chromatography, that is, inorganic substances contained in the dye solution are eliminated, so that inkjet recording is possible. ink and writing μ2
Suitable for preparing inks, etc. A dye solution can be produced.

Furthermore, according to the present invention, such a dye solution can be produced continuously and automatically, making it possible to mass-produce high-quality dyes.

[Brief explanation of drawings]

Fig. 1 is a schematic block diagram showing an embodiment of the apparatus according to the present invention, Fig. 2 is a block diagram showing the salt reduction processing unit of Fig. 1, and Fig. 3 shows the separation characteristics of the chroma column. FIG. 4 is a block diagram showing the control section of the apparatus shown in FIG. 1, and FIG. 5 is a flowchart 1 showing the operation of the salt reduction processing unit of the apparatus shown in FIG. 1. 21...Dye supply section, 22...Dye powder, 23...Dye pulp. 24...Blending tank, (19) 25...Pure water valve, 28...Pure water supply pipe, 27...Blending tank stirrer 28...Blending tank liquid level detector, 28... Filtration filter 31... Supply tank, 32... Supply pipe, 33... Valve, 41... Refining section, 42... Salt reduction processing unit, 43... Supply pulp opening/closing section, 44. ...Salt reduction filter section, 45...Discharge pulp opening/closing section, 46...Dye aqueous solution supply pipe, 47...Pure water supply pipe, 48...Secondary solution supply pipe, 51...Secondary Solution storage tank, 52... Supply pipe, 55... Discharge pipe. 56... Storage tank, (20) 57... Discharge pipe, 58... Inorganic salt solution discharge tank, 59... Discharge pipe, 60... Circulation pump, 61... Discharge pipe, 71. ...control section, 72...operation section, 73.74...discharge valve. 101...Controller, 102...Read-only memory. 103...Random access memory, +04...Switch, +05...Human output buffer circuit, lO8...Display device, 107...Drive circuit, Ill, 112...A/D converter, +13 ...Input buffer circuit, 121-12B...Drive circuit, +27...Output buffer circuit, 431.432,433...Supply valve, 441...
・Chromato column, 442...Inorganic salt concentration detector, 443...Dye concentration detector, 444...Outflow passage, 445...Liquid level position detector, 451.452,453...Discharge valve .

Claims (1)

[Claims] A dye purification apparatus comprising: a dye solution manufacturing means; a dye solution processing means for performing chromatography using the solution; and a liquid separation control means for separating a liquid discharged from the processing means. .