JPS60209212A - Device for removing dissolved oxygen in ink - Google Patents

Abstract

PURPOSE:To remove oxygen dissolved already in an ink by providing a heating means for the ink in an ink tank. CONSTITUTION:Air in the ink tank 1 is exhausted through a valve V2 by opening valves V1 and V2 and feeding inactive gas to the ink tank 1 from a gas source 4. After feeding the ink 2 from a valve V3, the valve V3 is closed, and the ink 2 is heated by a heating means 3 and fluidized with a fluidizing blade 5. After the air in the ink tank 1 is exhausted, the valve V1 may be closed but it is left open in order to prevent pressure rise in the ink tank 1 accompanying the heating of the ink 2. The heating temp. of the ink is selected within a range causing no degradation of the ink 2, but 35-90 deg.C is preferred.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an ink dissolved oxygen removal device that removes dissolved oxygen contained in ink during ink production.

[Field of Application of the Invention 1 The present invention can be used, for example, to manufacture ink for writing instruments such as felt pens and fountain pens. It is useful when used in the production of water-based ink used in recording methods that perform recording by ejecting it from an ejection orifice.

[Background of the invention and problems] Not only is it extremely difficult to isolate all processes from air during ink production, but the ink also contains dissolved oxygen because the ink raw materials already contain dissolved oxygen. This is an unavoidable situation.

However, when a large amount of dissolved oxygen is present in the ink, the dissolved oxygen oxidizes the components of the ink, resulting in the ink deteriorating in quality within a short period of time after production. This deterioration of the ink does not simply cause a change in the color of the ink, but also particularly in the inkjet recording method, which has an extremely dense structure due to the fact that minute amounts of ink are ejected at high speed several thousand times per second. This can clog the recording head and cause it to malfunction.

Conventionally, in order to reduce as much as possible the dissolved oxygen in the waste that causes such problems, ink that tends to increase dissolved oxygen has been stirred and mixed in a nitrogen atmosphere. That is, in some cases, the stirring tank is of a closed system, and the ink is stirred and mixed using a stirring device that can supply nitrogen gas inside. However, this ink agitation device only prevents the ink from coming into contact with air and increasing new dissolved oxygen when stirring and mixing the ink, but it also removes the dissolved oxygen originally contained in each ink raw material to be mixed. It's not possible. Therefore, if the existing amount of dissolved oxygen in each ink raw material is large, problems similar to those described above will occur.

[Object of the Invention] An object of the present invention is to make it possible to remove dissolved oxygen already dissolved in ink.

[Summary of the Invention] The present invention promotes the release of dissolved oxygen by heating ink. b [Structure and operation of the invention] A feature of the structure of the present invention is that it is an ink dissolved oxygen removal device in which an ink tank is provided with a heating means for heating the ink in the ink tank.

The apparatus of the present invention heats the ink using a heating means to create a thermal state in which gas is difficult to dissolve, thereby promoting the release of dissolved oxygen.

[Embodiment] An embodiment of the present invention will be described with reference to FIG. 1. In the figure, 1 is an ink tank, and has a heating means 3 for heating the ink 2 in the ink tank 1. The heating means 3 may be, for example, an electric heater, but in order to prevent the ink 2 from being overheated and burnt, steam heating is preferable. A gas source 4 such as a side light or a liquefied gas cylinder is connected to the upper part of the ink tank 1 via a valve V1. The gas of this gas source 4 needs to be a non-reactive gas that does not react with the ink 2, such as nitrogen, argon, or helium. Also, a valve v2 for spontaneously releasing the gas in the ink tank l is connected to the upper part of the ink-1.

The ink 2 or ink raw materials that have already been mixed are put into the ink tank 1 at a predetermined mixing ratio via a valve v3. Reference numeral 5 denotes an ink flow blade which is rotated by a motor M to flow the ink 2 in the ink tank l. Further, a temperature sensor S1 for sensing the temperature of the ink 2 is provided in the ink tank 1. This temperature sensor S1 is connected to a temperature measuring device 6,
Temperature measuring device 6 based on the signal from temperature sensor S1
The temperature of ink 2 can be detected by A controller C1 is connected to the temperature measuring device 6, and a signal from the temperature measuring device 6 causes the controller C1 to control the heating means 3.
is to be controlled.

Note that 4 is a valve connected to the bottom of the ink tank 1 to take out the ink 2 that has been processed.

To explain the operation of the above-mentioned device, first, valve V1
and ■Open 2, supply non-reactive gas from the gas source 4 into the ink tank l, and expel the air in the ink tank l from the valve v2.0 Next, open the valve v3 and fill the ink tank l with After the ink 2 or the ink raw materials of the blending method have been put in at a predetermined blending ratio, the valve v3 is closed, and the ink 2 is made to flow 4 by the ink flow blade 5 while being heated by the heating means 3.

Although the supply of non-reactive gas is not necessarily necessary,
This is preferable in the sense that it eliminates the opportunity for the ink 2 to come into contact with air as much as possible, making it easier to obtain a high dissolved oxygen removal effect. The supply of this non-reactive gas may be continued throughout the processing of ink 2 by this device, but once the air in the ink tank 1 is expelled, valve V1 is closed to save consumption of the non-reactive gas. You may also do so. however,
Valve 2 must be left open to prevent the pressure in the ink tank 1 from rising as the ink 2 heats up.

The heating of the ink 2 by the heating means 3 is carried out at a predetermined temperature determined within a range that does not alter the quality of the ink 2.This heating creates an atmosphere in which gas is difficult to dissolve into the liquid due to the temperature, thereby reducing dissolved oxygen in the ink 2. It promotes the release of At this time, it is preferable to flow the ink 2 using the ink flow blade 5, which is an ink flow means for flowing the ink 2 in the ink tank 1, because this further promotes the release of the dissolved oxygen in the ink 2. S1 is a device that senses the temperature of the space inside the ink tank l and a heating device 3.
However, in order to ensure accurate temperature control, it is preferable to directly sense the temperature of the ink 2. The heating temperature of the ink 2 varies depending on the type of ink, etc., but is generally preferably about 35 to 80°C.

After the ink 2 is heated and dissolved oxygen is removed as described above, the treated ink 2 is taken out by opening the valve V4.

In this embodiment, the valve v2 simply opens the inside of the ink tank l to the outside.
can also be connected to evacuation means (not shown) such as a pump. In particular, if an exhaust means is provided, not only will air be more reliably removed from the ink tank 1, but if the inside of the ink tank 1 is depressurized by the exhaust means, dissolved oxygen in the ink 2 will also be released due to this reduced pressure atmosphere. It has the advantage of being able to encourage

Although the ink flowing vane 5 serving as the ink flowing means in this embodiment is not necessarily necessary, as described above, this ink flowing means also causes the ink 2 to flow and promotes the release of dissolved oxygen.

Therefore, it is also preferable to determine the ink flow means from the viewpoint of the effect of promoting the release of dissolved oxygen. Other ink flowing means include, for example, a nozzle that blows up the ink 2 in the ink tank l in the form of a fountain or drops it in the form of a shower, a vibration device that shakes or vibrates the ink tank l, and a vibrating device that shakes or vibrates the ink tank l.
For example, an ultrasonic generator that applies ultrasonic vibrations may be used.

In particular, it has been confirmed that ultrasonic vibration is extremely effective in removing dissolved oxygen in the ink 2. A plurality of these fluidizing means can be used in combination, and furthermore, by providing a fluidizing means, it is possible to obtain a stirring and mixing effect when the ink raw materials are introduced into the ink tank 1. It is also preferable for the same reason to supply the non-reactive gas from below the surface of the ink 2.

Another embodiment of the present invention will be explained with reference to FIG.

A valve V2 is provided at the top of the ink tank 1 to naturally release the gas in the ink tank 1, and a valve V4 is provided at the bottom of the ink tank 1 to take out the ink 2 that has been processed. It is similar to that in FIG.

Inside the ink tank 1, a nozzle 7 is provided as an ink flow means for causing the ink 2 to flow, projecting upward from the bottom of the ink tank 1 and blowing up the ink 2 into a space inside the ink tank 1 in the form of a fountain. At the base of this nozzle 7, raw material containers 8 and 9 containing raw materials for the ink 2 are provided with valves v5 and 9, respectively. v6 and a flow meter 10. Valve vs SUV
6 and flow meter IO are connected to controller C2. Based on the signal from the flowmeter IO, the controller c2 controls valves V5. V,
After controlling the opening degree of V5. and supplying a certain flow rate, both valves V5. It closes V.

The nozzle 7 ejects the ink raw material sent in this way into the ink tank 1 by gas pressure from the gas source 11 similar to that explained in FIG. It also circulates and ejects water. Further, the ink tank 1 is provided with a heating means 3 for heating the ink 2, and this is controlled by a temperature sensor Sl, a temperature measuring device 6, and a controller CI, similar to the one in FIG. It is.

On the other hand, in this embodiment, a dissolved oxygen sensor S2 that senses dissolved oxygen in the ink 2 is provided in the ink tank l. This dissolved oxygen sensor S2 is connected to the dissolved oxygen measuring device 12, and the dissolved oxygen sensor S2 is connected to the dissolved oxygen measuring device 12. :2
v: 7/'', y:::2::;2::=.The dissolved oxygen measuring device 12 has a controller C.
3 is connected, and this controller controls the opening and closing of the valve V4 based on the signal from the dissolved oxygen measuring device 12. Moreover, a normal dissolved oxygen meter (o, o, meter) or the like can be used as the dissolved oxygen sensor S2 and the dissolved oxygen measuring device 12 for detecting dissolved oxygen.

Next, the operation will be explained. When valve v2 is opened, valve V5. When V6 is opened and ink raw materials are supplied, they are mixed and ejected from the nozzle 7 by the gas pressure of the non-reactive gas from the gas source 11. After a predetermined amount of ink 2 is supplied to the ink tank 1, the valve V5. ■
6 is closed, but the ink 2 in the ink tank 1 is circulated and ejected from the nozzle 7 to keep the ink 2 flowing. At the same time, due to the non-reactive gas ejected from the nozzle 7 together with the ink 2, the air in the ink tank 1 is
You will be kicked out of 2.

When the ink 2 is made to flow and heated to a predetermined temperature by the heating means 3, the dissolved oxygen in the ink 2 is released, and this is also discharged from the valve V2 together with the non-reactive gas. In particular, in this embodiment, the release of dissolved oxygen is not only promoted by simply scattering the ink 2 into the space within the ink tank 1, but also acts rapidly on the ink 2 when it is ejected from the nozzle 7. The release of dissolved oxygen in the ink 2 can also be promoted by changing the pressure. .

In this way, the dissolved oxygen removal process in the ink 2 continues, and when it is confirmed by the dissolved oxygen sensor S2 that the amount of dissolved oxygen has fallen below a predetermined level, the controller C3 opens the valve v4 and removes the ink 2. is sent to the next process. Therefore, it is possible to reliably reduce the amount of dissolved oxygen in the ink z to a predetermined level or less. The permissible level of dissolved oxygen is: Although it varies depending on the composition of the ink, it is especially 15pp for ink for inkjet recording method.
It is preferable that it is below.

Next, an experimental example of the apparatus according to the present invention will be explained.

The amount of dissolved oxygen in the ink was compared between when the ink was heated as in the present invention and when the ink was not heated. A device as shown in FIG. 1 was used to heat the ink, and the ink was maintained at a temperature of 60° C. for 20 hours without operating the ink flow blade. The ink was an inkjet recording ink containing a water-soluble dye, water, and glycols as composition components, and the experiment was conducted at an atmospheric pressure of 752 mm/g and a room temperature of 18°C.

As a result, the dissolved oxygen concentration in the ink before treatment was 21 pp■
On the other hand, after heat treatment, it decreased to 89P■.

[Effects of the Invention] According to the present invention, the release of dissolved oxygen in the ink is promoted by placing the ink in a heated atmosphere, so even if the ink raw material itself contains a large amount of dissolved oxygen,
The amount of dissolved oxygen in the ink can be made extremely small. Therefore, there is little concern that the ink will deteriorate due to oxidation of the ink composition components due to dissolved oxygen, and good ink storage stability can be obtained over a long period of time.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of an ink dissolved oxygen removing device according to the present invention, and FIG. 2 is an explanatory diagram showing another embodiment. l: ink tank, 2: ink, 3: heating means, 4.11:
Gas source, 5: Ink flow vane, 6: Temperature measuring device, -7
: Nozzle, 8.9: Raw material container, 1o dual flow meter, 12: Dissolved oxygen measuring device, vi-v, : Valve, Sl
: Temperature sensor, S2: Dissolved oxygen sensor, C, -C3: Controller. Applicant Canon Co., Ltd. Agent Yutaka 1) Yoshio

Claims (1)

[Claims] 1) An ink dissolved oxygen removal device characterized in that the ink tank is provided with a heating means for heating the liquid in the ink tank.