JPS59182864A - Apparatus for purification of dye - Google Patents

Abstract

PURPOSE:To enable the continuous production of purified dye suitable as the ink for writing utensils, checking the concentration of the salt according to the need, by using a means for the prparation of a dye solution in combination with a means for detecting the concentration of inorganic salt in the solution and a means for displaying the detected value. CONSTITUTION:The dye powder 22 is supplied from the dye reservior 21 to the mixing tank 24, and the prepared dye solution is fed through the supply tank 31 to the detector 46 to detect the concentration of inorganic salts by ion chromatography, etc. When the detected concentration displayed on a display is higher than a preset level (preferably <=5wt%), the solution is passed through a salt- rejection filter 43 to obtain purified dye.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a dye purification device, and in particular to a device for continuously supplying a purified dye suitable for preparing a recording liquid (generally referred to as ink) suitable for ink diene recording, writing instruments, etc. This invention relates to dye purification equipment.

[Prior Art] Conventionally, as inks used in an inkjet recording method in which recording is performed by ejecting ink in a recording vent from an ejection orifice using vibrations caused by a piezoelectric vibrator, various kinds of dyes 1. It is known that pigments are dissolved or dispersed in a liquid medium consisting of water or other organic solvents. 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 in which the main components are a water-soluble dye, water as its solvent, and glycols as a drying inhibitor.

Here, the water-soluble dye usually contains a large amount of inorganic salts such as i-chloride and sodium sulfate. These inorganic salts are not only those produced as by-products during the dye synthesis reaction, but also those that are actively added as salting-out agents, thickeners, 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 is ejected near the ejection orifice and the 11ν composition changes, precipitation of salts will occur. All of these are the most common causes of clogging of the top orifice, which should be avoided.

Therefore, in order to eliminate such adverse effects, there is a method of controlling iNJ so that the inorganic salt concentration is within a predetermined range (generally 0.5% by weight or less in the ink) during ink production. This is disadvantageous when using general commercially available dyes containing inorganic jus as impurities for the preparation of ink for recording ink or ink for writing instruments.

[Objective] In view of the above points, the first object of the present invention is to prepare Ijjj, Ijjj,
We provide a dye purification device that can continuously supply purified dye solution suitable for preparing inkjet recording ink, etc. It's about doing.

[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.

This is a dye supply section that stores 211 dye powder 22, and supplies the dye powder 22 to a mixing tank 24 via a dye valve 23. Further, pure water is supplied to the mixing tank 24 via a pure water supply vibrator 28 into which a pure water valve 25 is inserted.

In this mixing tank 24, the supplied dyed clay 31 powder 22 and pure water are mixed and dissolved by a mixing tank stirrer 27 to prepare 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 . 7. in the mixing tank. The dye powder particles that were not dissolved in pure water remain in the aqueous dye solution.
This is removed by a filtration filter 29. For this filter 29, a piece of filter paper, Fluorobor (trade name), or the like can be used. The aqueous dye solution from which particles and the like have been removed by passing through the filter 28 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, the supply tank 31 is provided with a valve 33 for controlling the liquid level, and the amount of the aqueous dye solution 't<k stored in the supply tank is kept below a certain value M.

Next, 41 is 7I' which eliminates inorganic salts from the dye aqueous solution.
This is the i manufacturing department. In this purification section 41, 42 is a salt reduction tank, 43 is a salt reduction filter, and 44 is a salt removal tank. An aqueous dye solution is supplied to the salt reduction tank 42 via the supply valve 32 . This supplied aqueous dye solution.

Stir with the low-salt tank stirring fi45 to homogenize the water # and make it free! A 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 will be described later, when the concentration of inorganic salts is at a predetermined level 16 (
For example, if it is detected that 59<To96) or J-, for a dye.

jA'i The ring pump 48 is operated to circulate the dye aqueous solution in the salt-reducing tank through the salt-reducing filter 43. For example, the A filter is an ultrafiltration filter.

Use a reverse osmosis filter, etc. Such a salt-reducing filter 43?
<1 ffi, inorganic salts such as sodium chloride and sodium sulfate contained in the dye aqueous solution are filtered from the dye aqueous solution as an aqueous solution, and tJ
F is issued. In this way, a portion of the water, which is the solvent for the dye, is initially discharged into the 4JL salt bath 44 together with the inorganic salts. Therefore, the dye aqueous solution is replenished with this discharged water, and the dye aqueous solution i.
Makoto IM via the pure water valve 4a so that water can be obtained.
Pure water is supplied to the tank 42.

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 dye aqueous solution in the tank 42 is detected by the salt reduction tank liquid level detector 50.

” The aqueous dye solution after being purified in a series (acupuncture),
It is discharged through a storage valve 51 into a storage tank 52 and stored therein.

FIG. 2 shows the control system of the device shown in 1I:A. Here, 61 is a controller, which controls the drive of each part.

62 is a read only memory (ROM) in which a control block diagram such as the operating procedure shown in FIG. 3 is written.

Reference numeral 63 denotes a random access memory (RAM) in which various types of data are stored.

In this example, the inorganic salt concentration detector 46 and the dye concentration +fy
An analog signal is output from the output device 47 of No. 4, and is outputted as a digital signal through A/D converters 64 and 65, respectively.
After being converted into a j-bow, it is supplied to the controller 61 via a human capacitor circuit 66. - Power, mixing tank liquid level detector 288
A decile signal is output from each of the salt reduction tank liquid level detectors 50 and sent to the controller 61 via an input buffer circuit 66.
supplied to

67 to 74 are each of the valves 23, 25, 49.
32 and 51, the agitators 27 and 45, and the circulation pump 48, respectively, and the drive circuit is supplied from the controller 61 via the output amplifier circuit 75 (on/off controlled by Ni). .

81 and 82 are a dye concentration range setting switch and a)-machine salt concentration range setting switch, respectively, and a signal corresponding to the set concentration range is supplied to the controller via the console input/output pamphlet 7 circuit 83. . Reference numerals 84 and 85 are a dye concentration indicator and an inorganic salt concentration indicator, respectively, which display the dye concentration value and the inorganic salt concentration value in the aqueous dye solution being purified. Therefore, this device'
By performing the 6th operation, the quality of the aqueous dye solution being manufactured can be easily determined.

The values set for the dye density & range and the inorganic salt concentration range by the switches 81 and 82 are stored in the RAM 63 -IPr. The detected concentration values of inorganic salts and dye in the aqueous dye solution being purified, which are detected by the inorganic salt concentration detector 46 and the dye concentration detector 47, are determined by the comparison unit 81 of the controller.
1, it is compared with the set value, and based on the comparison result,
The driving of each load such as the circulation pump 48 is controlled as described later.

FIG. 3 shows the operation flow of the apparatus shown in FIG. In the figure, steps STI to ST4 are steps for maintaining a constant amount of the aqueous solution in the mixing tank 24. That is, in step STI, it is determined from the output of the mixing tank liquid level detector 28 whether the liquid level of the dye aqueous solution in the mixing tank 24 is at a level 2 with respect to the lower level 1 that defines a predetermined setting range. Detect. If the IN is lower than that, the process proceeds to step ST2; otherwise, the process proceeds to step ST3. Procedure ST
In Step 2, the dye valve 23 and pure water/help 25 are opened, and predetermined amounts of dye powder and pure water are respectively introduced into the mixing tank 28. In the mixing tank 24, since the stirrer 27 is always in operation state 7U1, the dye powder introduced is dissolved in pure water and the dye water volume is mixed. Step ST3
Then, the liquid level in the mixing tank 24 determines the setting range according to the output of the liquid flow detector 28)j! Detect whether it is "2" higher than the high position. If it is above that high position, proceed to step ST4, otherwise proceed to hand++m5r5. In step ST4, the dye valve 23 and pure water valve 25, which are in the open state, are closed to stop the supply of dye powder and pure water.

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

In step ST7, it is determined whether the dye concentration detected by the detector 47 is within the dye concentration range set by the switch 81. If it is determined that it is within the setting range, proceed to step ST8; otherwise,
Proceed to step ST9. In step ST8, it is determined whether the concentration of inorganic salts detected by the detector 48 is within the range of values set by the switch 82. If it is determined that it is within the setting range, proceed to step 5TIO,
If not, proceed to step ST8.

In +1AST9, it is determined whether the liquid level in the salt reduction tank 42 detected by the detector 50 is above the high position that defines the setting range. If it is below that height, step 5
Proceed to TII, and if not, proceed to step 5T12. In step 5TII, the supply/help 32 and the pure water valve 49 are opened/closed to reduce liters! ! A dye aqueous solution and pure water are supplied into the tank 42. 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.

After this, the process proceeds to step 5T13. - In step 1 5T12, the supply valve 32 and the U pure water/water tank 49 are closed.

At 11fisT13, the circulation pump 48 is activated,
) The dye aqueous solution in the tank 42 is filtered through the al18 field filter 4.
3 to remove inorganic salts from the aqueous dye solution.

1- As mentioned above, if the IJ: material concentration and inorganic salt concentration are outside the set range, step 5TII and step 5T13
Alternatively, repeat the routine that goes through ST12 and Step 5T13 to set the dyeing method concentration and inorganic salt concentration to values within the set ranges. After the image density falls within the set range, proceed to Step 5, 5TIO.

At 5TIO, it is determined whether the liquid level in the salt reduction tank 42 detected by the detector 50 is two feet below the low position that defines the setting range. If it is older than the lower position, proceed to ]'-111fj S T l 4; otherwise proceed to step 5T15. 'f-111fi S
At T14, the operation of the circulation pump 48 is stopped and the storage valve 51 is opened. As a result, the purified dye aqueous solution obtained in the salt reduction tank 42 is supplied to the storage tank 52.

]"l1lflST15 closes the storage valve 51 and opens the supply valve 32 and pure water valve 49 to end the supply to the storage tank 52 and reduce the amount of dye aqueous solution in the d-recording tank 42. Increase the liquid level so that it is within the set range.

After this, repeat steps 5TII, 5TI3 or f as described above.
By repeating the routine passing through 111nST12 and 5T13, a predetermined amount of aqueous dye solution whose dye concentration and inorganic salt concentration are within the set range is obtained in the reduced salt +1Il142. After this, the process proceeds to step 5T14 described above.

As described above, in the present embodiment, the aqueous dye solution is purified in the refining section 41 every -.times.1-.

``Effects'' 2 As explained above, according to the present invention, when producing a dye solution, the concentration of inorganic salts contained in the dye solution is detected, and the detection results are displayed. This allows the operator to check the detected concentration as needed.
It is suitable for producing purified dye solutions suitable for preparing inkjet recording inks, writing instrument inks, etc.

[Brief explanation of the drawing]

i) Figure 1 is a schematic configuration diagram showing an embodiment of the apparatus according to the present invention, Figure 2 is a block diagram showing the control section of the apparatus shown in Figure 1, and Figure 3 is a diagram showing the operation of the apparatus shown in Figure 1. It is a flowchart which shows. 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 stirrer 28... Preparation tank liquid level detector, 29... Filtration filter, 31... Supply tank, 32... Supply valve, 33... Valve, 41... Purification section, 42 ...Reduced IJJ tank, 43...71 Table 18 filter, 44...Exhaust I! ! Tank, 45... Salt reduction horizontal stirrer, 46... Inorganic salt concentration detector, 47... Dye concentration detector, 48... Circulation pump, 48... Pure water valve, 50... Salt reduction tank liquid level detector, 51...Storage valve, 52...Storage tank, 61...Controller, 62...Leat only memory (ROM), 63...
Lanotum Access Memory (RAM). 64.65...A/D converter, 66...7 input puff circuits, 67-74...drive circuit, 75...4977 output circuits, 81...dye concentration range setting switch, 82... Inorganic salt concentration range setting switch, Sochi, 83... Console input/output 4777 circuit, 84... Dye concentration display, 85... Inorganic salt concentration display, 611... Comparison section.

Claims (1)

[Claims] A dye purification apparatus comprising means for producing dye droplets, means for detecting the concentration of inorganic salts in the solution, and means for displaying the concentration of inorganic salts for displaying the detected value.