JP2009138021A - Method for preparing liquid composition for inkjet recording and inkjet recording device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording device in which, even when a liquid composition for inkjet recording to which a bactericide and an anti-mold agent are not added is used, quality deterioration of the liquid composition for inkjet recording due to propagation of mold and bacteria is suppressed over a long period of time. <P>SOLUTION: The inkjet recording device comprises: a liquid droplet discharge means which is provided with at least a retention container which retains a liquid composition for inkjet recording, a liquid droplet discharge face and a nozzle disposed on the liquid droplet discharge face, and which drips and discharges the liquid composition for inkjet recording from the nozzle; a supply pipe through which the liquid composition for inkjet recording is transferred from the retention container to the liquid droplet discharge means; and a fine bubble generator which supplies fine bubbles into the retention containers. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a liquid composition for ink jet recording used for forming an image in an ink jet recording system, and an ink jet recording apparatus.

  Ink-jet recording liquid compositions such as inks used for ink-jet recording and liquids (so-called treatment liquids) that promote aggregation of pigments in inks as necessary to prevent bleeding are usually used in factories. After being blended, it is delivered to consumers through distribution channels such as stores. And the liquid composition for inkjet recording is utilized by the consumer.

As described above, since the time span from the preparation of the liquid composition for ink jet recording to the complete consumption for image formation is very long, the quality of the liquid composition for ink jet recording during this period is stable. It is extremely important to be maintained.
Therefore, it is known to add antibacterial agents and fungicides to the liquid composition for ink jet recording in order to suppress the deterioration of the quality of the liquid composition for ink jet recording due to the growth of mold and bacteria over a long period of time. (For example, see Patent Document 1).

On the other hand, in recent years, a technique has been proposed in which fine bubbles having a diameter of several tens of μm or less are generated by swirling air and water at a very high speed in a container (see Patent Document 2 and Non-Patent Document 1). Compared with conventional bubbles with a diameter on the order of millimeters or larger, these bubbles are contracted and disappeared in the liquid, have a bioactive effect, and the bubbles are negatively charged. Therefore, it has special effects such as easy adhesion to positive things. And if microbubbles are utilized, it is known that various applications, such as natural environment purification | cleaning, such as water quality purification | cleaning, and sterilization treatment, are possible, for example.
JP-A-10-230610 Japanese Patent No. 3397154 Nano Planet Research Laboratories Co., Ltd. (http://www.nanoplanet.co.jp/index.html)

As described above, a bactericidal agent and an antifungal agent are added to the liquid composition for ink jet recording, but these components are components that are not necessary for the formation of an image and may be antibacterial in some cases. Since other properties may be deteriorated, it can be said that it is preferably not added originally.
The present invention has been made in view of the above circumstances, and suppresses deterioration in quality due to the growth of mold and bacteria over a long period of time after producing a liquid composition for ink jet recording to which no bactericidal agent or fungicide is added. And a method for producing an inkjet recording liquid composition, and a liquid composition for inkjet recording due to the growth of mold and bacteria over a long period of time, even if an inkjet recording liquid composition to which no bactericidal or antifungal agent is added is used. It is an object of the present invention to provide an inkjet recording apparatus that suppresses quality deterioration of a product.

The above-mentioned subject is achieved by the following present invention. That is,
The invention according to claim 1
At least a mixed liquid preparation step of preparing a mixed liquid in which a pigment dispersion, a water-soluble organic solvent, a surfactant, and water are mixed;
It is a method for producing a liquid composition for ink jet recording, characterized by supplying fine bubbles to at least one liquid selected from the pigment dispersion and the mixed liquid.

The invention according to claim 2
At least a mixed liquid preparation step of preparing a mixed liquid obtained by mixing a flocculant that promotes aggregation of the pigment contained in the ink, a water-soluble organic solvent, a surfactant, and water;
A method for producing a liquid composition for ink-jet recording, wherein the mixed liquid is processed by supplying fine bubbles.

The invention according to claim 3 is:
The liquid for inkjet recording according to claim 1, further comprising a degassing step of degassing a gas component dissolved in the liquid mixture by applying an ultrasonic wave to the liquid mixture. It is a manufacturing method of a composition.

The invention according to claim 4 is:
A storage container for storing a liquid composition for inkjet recording;
A droplet discharge means that includes at least a droplet discharge surface and a nozzle disposed on the droplet discharge surface, and discharges the inkjet recording liquid composition from the nozzle in the form of droplets;
A supply pipe for transferring the liquid composition for inkjet recording from the storage container to the droplet discharge means;
A fine bubble generator for supplying fine bubbles into the storage container;
An ink jet recording apparatus comprising:

The invention according to claim 5 is:
The inkjet recording apparatus according to claim 4, further comprising an ultrasonic wave application unit that applies ultrasonic waves to the liquid composition for inkjet recording stored in the storage container.

The invention according to claim 6 is:
6. The ink jet recording apparatus according to claim 5, wherein the droplet discharge means includes a heating element that heats the liquid flowing in the nozzle.

The invention according to claim 7 is:
A recovery section for recovering the ink jet recording liquid composition discharged from the droplet discharge means; and a recovery pipe for transferring the recovered ink jet recording liquid composition from the recovery section to the storage container. The ink jet recording apparatus according to claim 4, further comprising: an ink jet recording apparatus according to claim 4.

The invention according to claim 8 is:
Capacity of the storage container is an ink jet recording apparatus according to any one of claims 4-7, characterized in that in the range of 500 cm ³ or more 5000 cm ³ or less.

The invention according to claim 9 is
The ink jet recording apparatus according to claim 5, wherein the liquid composition for ink jet recording is an ink containing a pigment.

As described above, according to the first aspect of the present invention, after manufacturing a liquid composition (ink) for ink jet recording to which no bactericidal agent or fungicidal agent is added, it is possible to prevent mold and bacteria over a long period of time. It is possible to provide a method for producing a liquid composition for ink jet recording that suppresses quality deterioration due to breeding.
According to the invention described in claim 2, after producing a liquid composition (treatment liquid) for ink jet recording to which no bactericides or fungicides are added, quality deterioration due to the growth of mold or bacteria over a long period of time. The manufacturing method of the liquid composition for inkjet recording to suppress can be provided.
According to invention of Claim 3, the manufacturing method of the liquid composition for inkjet recording which deaerated the gas melt | dissolved by the fine bubble process can be provided.

According to the fourth aspect of the present invention, even if an ink jet recording liquid composition to which no bactericidal agent or fungicidal agent is added is used, the liquid composition for ink jet recording due to the growth of mold or bacteria over a long period of time is used. An ink jet recording apparatus that suppresses quality deterioration can be provided.
According to the invention described in claim 5, it is possible to provide an ink jet recording apparatus capable of degassing a gas dissolved in the liquid composition for ink jet recording by the fine bubble treatment.
According to the sixth aspect of the present invention, it is possible to provide an ink jet recording apparatus capable of suppressing ejection failure due to generation of bubbles due to heating during ejection of the liquid composition for ink jet recording.
According to the seventh aspect of the present invention, an ink jet recording apparatus having high utilization efficiency of the liquid composition for ink jet recording can be provided.
According to the invention described in claim 8, it is possible to provide an ink jet recording apparatus capable of forming a large amount of images at high speed.
According to the ninth aspect of the present invention, it is possible to provide an ink jet recording apparatus capable of suppressing variations in color density during image formation even when an ink containing a pigment is used.

<Method for producing liquid composition for ink jet recording>
The method for producing a liquid composition for inkjet recording of the present invention includes at least a mixed liquid preparation step of preparing a mixed liquid in which a pigment dispersion, a water-soluble organic solvent, a surfactant, and water are mixed,
The present invention is characterized in that fine bubbles are supplied to at least one liquid selected from the pigment dispersion and the mixed liquid for processing (hereinafter, this embodiment is referred to as “first manufacturing method”). Sometimes).

  The method for producing a liquid composition for ink jet recording according to the present invention comprises a mixed liquid obtained by mixing a flocculant that promotes aggregation of a pigment contained in an ink, a water-soluble organic solvent, a surfactant, and water. It includes at least a mixed liquid preparation step for preparing, and is characterized by supplying fine bubbles to the mixed liquid for processing (hereinafter, this embodiment may be referred to as “second manufacturing method”).

The first manufacturing method relates to an ink containing a pigment (pigment ink), and the second manufacturing method relates to a treatment liquid.
Moreover, in the 1st, 2nd manufacturing method, it is preferable to implement the filtration process which filters a liquid mixture after passing through a liquid mixture preparation process. Furthermore, it is preferable to perform a deaeration process after passing through a liquid mixture preparation process or after passing through a filtration process. In addition, the degassing step can be performed not only by ultrasonic treatment on the mixed solution but also by degassing under reduced pressure or the like.

  Among pigment dispersions, water-soluble organic solvents, surfactants, water, and flocculants that are raw materials used in the production of pigment inks and treatment liquids, water-soluble organic solvents, surfactants, and flocculants are subjected to commercial purification treatments. Since a container in a sealed container such as a bowl or bottle is used, there is very little possibility that bacteria will be generated due to these components. Moreover, as water, what was fully refine | purified, such as ultrapure water and ion-exchange water, is used, Therefore The possibility of generating a microbe etc. resulting from this is very scarce.

  However, since the pigment dispersion is prepared by preparing a plurality of raw materials in advance, bacteria may be mixed in the preparation process. Further, in the mixed liquid preparation process, various raw material components constituting the pigment ink and the processing liquid are exposed to the atmosphere or come into contact with dirt attached to the inner wall of the container used for mixing. There is a possibility of contamination.

From this point of view, when producing a pigment ink, by supplying fine bubbles to at least one liquid selected from the pigment dispersion and the mixed liquid before passing through the degassing step, the pigment ink is processed. The bacteria mixed in the pigment ink can be sterilized. In order to make the sterilization of the pigment ink more reliable, the treatment with fine bubbles (hereinafter sometimes referred to as “fine bubble treatment”) is more preferably performed on the mixed solution than the pigment dispersion. .
Moreover, when manufacturing a process liquid, the microbe mixed in a process liquid can be sterilized by supplying a microbubble with respect to the liquid mixture before passing through a deaeration process, and processing it.

  Therefore, in the ink manufactured using the first manufacturing method and the treatment liquid manufactured using the second manufacturing method, even if no bactericidal agent or antifungal agent is added, it is long-term. It is possible to suppress quality deterioration due to the growth of mold and bacteria. In addition, since it is not necessary to add components that are not essential for image formation, such as antibacterial agents and antifungal agents, various side effects due to the addition of these components; for example, deterioration of ejection characteristics of the recording head In addition, the storage stability is not deteriorated.

  The microbubble treatment conditions for the pigment dispersion and the mixed liquid are not particularly limited as long as sufficient sterilization can be performed, but the supply amount of microbubbles per 1 L of liquid to be subjected to the microbubble treatment Is preferably at a rate of 0.5 L / min or more, and more preferably at a rate of 2 L / min or more. If the supply amount of fine bubbles is less than 0.5 L / min, sufficient sterilization may not be performed. In addition, although the upper limit of the supply amount of fine bubbles is not particularly limited, since the amount of gas dissolved in the liquid increases excessively, there may be inconveniences such as taking time in the deaeration process, so in practice, It is preferable that it is 1 L / min or less.

The fine bubble treatment time is preferably in the range of 1 min to 10 min, and more preferably in the range of 5 min to 10 min. If it is less than 1 min, sufficient sterilization may not be performed. In addition, if it exceeds 10 min, the processing time becomes long, so the amount of gas dissolved in the liquid increases too much, and it takes time in the deaeration process, and the productivity of the pigment ink and the processing liquid decreases. There is a case.
Next, details of each step will be described.

-Mixture preparation process-
In the mixed liquid preparation step, various raw material components constituting the liquid composition for ink jet recording such as pigment ink and processing liquid are mixed. The mixing method is not particularly limited, and a known method can be used. For example, after various raw material components are charged into a container, stirring and mixing can be performed with a stirring bar such as a propeller.
In addition, about the pigment dispersion liquid used at a liquid mixture preparation process, what carried out the centrifugation process previously and removed the coarse particle component may be used. Centrifugation can be carried out at 7000 rpm to 9000 rpm for about 20 min to 30 min. However, when the fine bubble treatment is performed, the amount of coarse particles in the mixed solution can be reduced even if the mixed solution is prepared without the centrifugal separation treatment. This is presumed to be due to the action of crushing coarse particles in the microbubble treatment.
In addition, the fine bubble treatment may be performed while mixing and stirring the mixed solution, or may be performed after mixing and stirring. However, in the latter case, the fine bubbles are mixed with the mixed solution evenly. It is preferable to gently stir.

-Filtration process-
In the filtration step, the mixed solution is filtered to remove foreign matters and precipitates. As a filtration method, a known method can be used, and for example, a filter can be used. In addition, as a mesh of a filter, the thing within the range of about 1 micrometer-20 micrometers can be selected. Further, the material of the filter may be any material as long as it does not dissolve in the liquid mixture or deteriorates immediately by the liquid mixture. For example, PVDF (polyvinylidene fluoride), PP (polypropylene), or the like can be used.
In addition, when a microbubble process is not performed during a liquid mixture preparation process or before implementation of a filtration process, it can be implemented after finishing a filtration process.

-Deaeration process-
In the deaeration step, the mixed solution that has undergone the filtration step is deaerated. The deaeration method is not particularly limited, and a known method can be used. For example, vacuum deaeration, application of ultrasonic waves, and the like can be mentioned, and among these, application of ultrasonic waves is more preferable. The ultrasonic treatment conditions can be selected as appropriate. For example, if the output is 200 W and the frequency is 28 KHz, the treatment time is preferably in the range of 5 minutes to 30 minutes.
In order to improve the sterilization effect, it is preferable to increase the microbubble treatment time or increase the amount of fine bubbles to be generated. In this case, however, the amount of gas components dissolved in the mixed liquid also increases. For this reason, when used in an ink jet recording apparatus with insufficient deaeration, the dissolved gas is bubbled when the ink or the processing liquid is ejected from the recording head. There is a case.
Therefore, in such a case, it is particularly preferable to perform a degassing step, and it is preferable to select a degassing condition so that more dissolved gas can be degassed.

  The liquid composition for inkjet recording obtained through the above deaeration process is filled in a container such as an ink cartridge.

  Next, the fine bubble treatment of the pigment dispersion or mixed liquid will be described with a specific example. FIG. 1 is a schematic diagram showing an example of a microbubble processing apparatus used for microbubble processing, in which 100 is a microbubble processing apparatus, 110 is a first raw material supply pipe, and 112 is a second raw material supply. Reference numeral 120 denotes a microbubble generator, 122 denotes a liquid supply pipe, 124 denotes a pump, 126 denotes a gas supply pipe, 130 denotes a container, and 140 denotes a liquid (pigment dispersion or mixed liquid).

  The fine bubble processing apparatus 100 shown in FIG. 1 includes a container 130, a first raw material supply pipe 110 and a second raw material supply pipe 112 that supply a raw material solution to the container 130, and a fine structure disposed at the bottom of the container 130. A bubble generator, a pump 124 disposed outside the container 130, a liquid supply pipe 122 having one end connected to the bottom side of the side surface of the container 130 and the other end connected to the fine bubble generator 120, and a liquid A pump 124 disposed in the middle of the supply pipe 122 and a gas supply pipe 126 having one end provided in the container 130 and the other end connected to the microbubble generator 120 are configured.

  When the microbubble processing is performed on the ink mixture using the microbubble processing apparatus 100, first, the pigment dispersion is supplied into the container 130 through the first raw material supply pipe 110, and the second raw material is supplied. A solution in which a water-soluble organic solvent, a surfactant, water, and other various additives used as necessary are mixed in advance is supplied into the container 130 through the tube 112. When a predetermined amount of each component is put into the container 130, the fine bubbles generated in the fine bubble generator 120 are finely bubbled while being stirred by a stirrer (not shown) disposed in the container 130 (for example, a propeller). The liquid is supplied into the mixed liquid 140 filled in the container 130 from a generating port (not shown). Thereby, the liquid mixture 140 can be processed with fine bubbles.

  When the fine bubbles are generated by the fine bubble generator 120, the mixed liquid 140 filled in the container 130 through the liquid supply pipe 122 and the outside air (air) through the gas supply pipe 126 are generated. The mixture is supplied to the device 120, and a mixed solution containing fine bubbles is generated in the fine bubble generating device 120 by rotating the mixed solution and air at an ultra high speed, and discharged to the outside of the fine bubble generating device 120. Here, the gas supplied to the fine bubble generating device 120 via the gas supply pipe 126 is not limited to air, and may be other gas such as nitrogen gas.

On the other hand, when the fine dispersion treatment is performed on the pigment dispersion, the apparatus in which the second raw material supply pipe 112 is removed from the fine foam treatment apparatus 100 shown in FIG. 1 is used, or the valve of the second raw material supply pipe 112 is closed. What is necessary is just to process a fine bubble in the state.
When the mixed liquid for the treatment liquid is subjected to the fine bubble treatment, an apparatus in which the first raw material supply pipe 110 is removed from the fine bubble treatment apparatus 100 shown in FIG. 1 is used, or a valve of the first raw material supply pipe 110 is used. What is necessary is just to process a fine bubble in the closed state. Note that the flocculant may be directly charged into the container 130 or may be mixed in advance in the liquid flowing in the second raw material supply pipe 112.

<Inkjet recording apparatus>
Next, the ink jet recording apparatus of the present invention will be described. The ink jet recording apparatus of the present invention includes at least a storage container for storing a liquid composition for ink jet recording, a liquid droplet ejection surface, and a nozzle disposed on the liquid droplet ejection surface, and the ink jet recording liquid composition is a liquid droplet. Droplet discharge means for discharging from the nozzle in the form of a liquid, a supply pipe for transferring the ink jet recording liquid composition from the storage container to the droplet discharge means, and fine bubbles for supplying fine bubbles into the storage container And a generator.

In the ink jet recording apparatus of the present invention, the fine bubble treatment is performed on the liquid composition for ink jet recording by supplying fine bubbles from the fine bubble generating device into the liquid composition for ink jet recording stored in the storage container. Can be applied. For this reason, even if a bactericidal agent or a fungicide is not added to the liquid composition for ink jet recording stored in the storage container, it is possible to suppress quality deterioration due to the growth of mold and bacteria over a long period of time. In addition, since it is not necessary to add components that are not essential for image formation, such as antibacterial agents and antifungal agents, various side effects due to the addition of these components; for example, deterioration of ejection characteristics of the recording head In addition, the storage stability is not deteriorated.
In addition, when the liquid composition for inkjet recording stored in the storage container is an ink containing a pigment, aggregates of the pigment are formed with the passage of time, and coarse particles are generated or dispersibility is increased. There is a tendency to deteriorate. However, in the present invention, since the fine bubble treatment is performed, such a problem can be suppressed. This is presumed to be due to the action of crushing coarse particles in the microbubble treatment.
The timing for performing the fine bubble processing is not particularly limited. For example, it may be automatically performed when the inkjet recording apparatus is driven or stopped, or at regular time intervals such as once a month. You may carry out automatically and may carry out a microbubble process compulsorily at arbitrary timings.

The ink jet recording apparatus of the present invention may be a small ink jet recording apparatus for home use or office use. However, in such an apparatus, since the storage container is small, the liquid composition for ink-jet recording in the storage container is consumed at an early stage, and in terms of cost performance, there is often no great advantage. .
On the other hand, in a so-called large-scale ink jet recording apparatus capable of forming a large amount of images at high speed (an apparatus having a storage container capacity of 500 cm ³ (0.5 L) or more and 5000 cm ³ (5 L) or less), a large amount of ink jet recording is performed. The liquid composition for use will be stored in the storage container for a long time. For this reason, it is extremely important to suppress the deterioration of the quality of the liquid composition for ink jet recording due to the growth of mold and bacteria over a long period of time. In addition, since the size of the ink jet recording apparatus and the storage container is large, it is also easy to arrange the fine bubble generating device inside or around the storage container. For this reason, the ink jet recording apparatus of the present invention is particularly preferably a large ink jet recording apparatus.

  On the other hand, when the liquid composition for ink jet recording is treated with fine bubbles, the amount of gas dissolved in the liquid composition for ink jet recording increases. For this reason, the inkjet recording apparatus is provided with an ultrasonic application means for applying ultrasonic waves to the liquid composition for inkjet recording stored in the storage container so that the deaeration process can be performed after the microbubble processing. Is preferred.

The droplet discharge means includes a heat generating element that heats the liquid flowing in the nozzle, and a piezoelectric that vibrates the liquid flowing in the nozzle, even in a so-called thermal method that uses this heat generating element to discharge a droplet from the nozzle. A so-called piezo method may be used in which an element is provided and droplets are ejected from the nozzle using this piezoelectric element.
However, when the liquid composition for ink jet recording is treated with fine bubbles, the amount of gas dissolved in the liquid composition for ink jet recording increases. When an object is heated, the gas dissolved in the liquid is vaporized to generate bubbles, which may easily cause a discharge failure of droplets discharged from the droplet discharge means. From this point, when using a thermal type droplet discharge means, it is particularly preferable to use it in combination with an ultrasonic wave application means. In this case, ejection failure at the time of droplet ejection can be more reliably suppressed.

Further, in order to improve the utilization efficiency of the liquid composition for ink jet recording, the ink jet recording apparatus preferably has a configuration capable of collecting the liquid droplets ejected from the liquid droplet ejecting means.
In this case, the ink jet recording apparatus includes a recovery unit for recovering the liquid composition for ink jet recording discharged from the droplet discharge means, and a recovery tube for transferring the recovered liquid composition for ink jet recording from the recovered liquid composition for ink jet recording to the storage container. And are preferably further provided.

As the liquid composition for inkjet recording, at least an ink can be used, and a treatment liquid can be used together with the ink. When a plurality of types of liquid compositions for ink jet recording are used, a storage container corresponding to each liquid composition for ink jet recording is provided. The color material contained in the ink may be either a pigment or a dye.
For ink containing pigments, if the ink jet recording apparatus does not operate for a long time, the pigment settles and accumulates in the storage container, and the pigment concentration changes between the liquid surface and the bottom surface in the storage container. May come. When an image is formed in such a state, variations in color density will occur. However, in the ink jet recording apparatus of the present invention, when the fine bubble processing is performed, the ink in the storage container is gently agitated, so that the above-described problems can be suppressed.

The droplet discharge means has a long recording head whose length in the width direction is about the same as or larger than the width of the recording paper transported during image formation (length in the direction orthogonal to the transport direction). A so-called FWA (Full Width Array) type recording head is preferable. This type of recording head is often used in so-called large machines capable of forming a large amount of images at high speed. In addition, as many recording heads as the number of types of ink-jet recording liquid compositions to be used can be arranged in the recording paper conveyance direction. For example, if four inks consisting of yellow (Y), magenta (M), cyan (C) and black (K) and five recording heads corresponding to the processing liquid are arranged along the transport direction, full color Images can be formed.
However, in addition to the FWA type, the droplet discharge means may be of a small size that can be scanned in a direction orthogonal to the recording paper conveyance direction.

-Specific examples of inkjet recording devices-
Next, specific examples of the ink jet recording apparatus of the present invention will be described with reference to the drawings. FIG. 2 is a schematic diagram showing one configuration example of the ink jet recording apparatus of the present invention, which mainly shows a diagram focusing on the transfer path of the liquid composition for ink jet recording in the apparatus, and other configurations. The description is omitted.
In FIG. 2, reference numeral 200 denotes an ink jet recording apparatus, 210 denotes a droplet discharge means, 220 denotes a fine bubble generating apparatus, 230 denotes an ultrasonic wave application means, 240 denotes a collection unit, 250, 252 and 254 denote pumps, and 260 denotes a filter. 270 is a supply pipe, 272 is a (undischarged liquid) recovery pipe, 274 is a (discharge liquid) recovery pipe, 276 is a circulation pipe, 278 is a gas supply pipe, 280 is a storage container, and 290 is a liquid composition for inkjet recording. And arrows indicate the flow direction of the liquid or gas.

The main part of the ink jet recording apparatus 200 shown in FIG. 2 includes a storage container 280 and a droplet discharge means 210.
Here, a fine bubble generating device 220 is provided on the bottom side of the side surface of the storage container 280 so that liquid containing fine bubbles can be discharged from the fine bubble generating device 220 to the storage container 280. The fine bubble generating device 220 is connected to the gas supply pipe 278 and the circulation pipe 276, and is used for ink jet recording in which outside air (air) is stored in the storage container 280 through the gas supply pipe 278. The liquid composition 290 is supplied to the fine bubble generator 220. The end of the circulation pipe 276 that is not connected to the fine bubble generating device 220 is connected to the bottom side of the side surface of the storage container 280 (however, the surface opposite to the side where the fine bubble generating device 220 is disposed). A pump 254 is arranged in the middle of the circulation pipe 276. In addition, ultrasonic application means 230 is disposed at the bottom of the storage container 280.
In addition, the ultrasonic application means 230 does not need to be provided, and instead of the ultrasonic application means 230, a defoaming device (for example, a commercially available product such as Bab Shut Type S Nippon Oil Co., Ltd., defoaming capacity: 100L / Min etc.) can also be used. The fine bubble generating device 220 may be disposed in the storage container 280.

On the other hand, the droplet discharge means 210 and the storage container 280 are connected by a supply pipe 270, and a pump 250 is provided in the middle of the supply pipe 270. The supply pipe 270 has a suction port below the liquid level of the ink jet recording liquid composition 290 so that the ink jet recording liquid composition 290 in the storage container 280 can be sucked and supplied to the droplet discharge means 210. It is provided so that it may be located in the side.
Further, the droplet discharge means 210 and the storage container 280 are connected by a (undischarged liquid) recovery pipe 272, and are supplied to the droplet discharge means 210 via the supply pipe 270, but are not discharged. The liquid composition 290 can be recovered into the storage container 280 and reused.

When forming an image, an inkjet recording liquid composition 290 discharged from a predetermined nozzle of the droplet discharge means 210 is applied to a surface of a recording medium (not shown) at a predetermined timing in accordance with document image information. In addition, the liquid composition for ink jet recording 290 discharged at the time of non-image formation is recovered by the recovery unit 240 when the droplet discharge unit 210 is maintained. When the inkjet recording liquid composition 290 is discharged during non-image formation, the recovery unit 240 moves the droplet discharge unit 210 and / or the recovery unit 240 to move the droplet discharge unit 210. It arrange | positions in the position facing a surface.
The shape of the collection unit 240 is not particularly limited, and may be any shape that is suitable for collecting the liquid composition 290 for ink jet recording discharged from the droplet discharge unit 210. For example, the shape may be a bowl shape. In this case, the ink jet recording liquid composition 290 is received and collected in a state in which the opening of the ridge is opposed to the droplet discharge surface.

  The recovery unit 240 and the storage container 280 are connected to the (discharge liquid) recovery pipe 274, and the ink jet recording liquid composition 290 recovered by the recovery part 240 is transferred to the storage container 274 via the recovery pipe 274. Transported and reused. In the middle of the recovery pipe 274, a pump 252 is provided upstream in the liquid flow direction, and a filter 260 is provided downstream in the liquid flow direction.

  When microbubbles are generated by the microbubble generator 220, the inkjet recording liquid composition 290 stored in the storage container 280 via the circulation pipe 276 and the outside air (air) via the gas supply pipe 278 are finely divided. The mixture is supplied to the bubble generating device 220, and a mixed solution containing fine bubbles is generated in the fine bubble generating device 220 by rotating the mixed solution and air at an ultra-high speed. Discharge into the container 280). Here, the gas supplied to the fine bubble generating device 220 via the gas supply pipe 278 is not limited to air, and may be other gas such as nitrogen gas.

  In addition, during the fine bubble treatment or immediately after the treatment, since the concentration of the gas dissolved in the liquid composition 290 for ink jet recording stored in the storage container 280 becomes high, it is preferable to perform the deaeration treatment. This degassing process can be performed by applying ultrasonic waves to the liquid composition 290 for ink jet recording stored in the storage container 280 by the ultrasonic wave application means 230.

-Microbubble generator-
Next, the fine bubble generator used in the present invention will be described. The fine bubble generator used in the present invention is not particularly limited in its configuration as long as fine bubbles having an average diameter of 100 μm or less can be generated immediately after the fine bubbles are discharged from the fine bubble generator. It is preferable to be a swivel type in which fine bubbles are generated by rotating a gas and a liquid at an ultra high speed in a container. An example of the swirl type fine bubble generator is a swirl type fine bubble generator described in Patent Document 2.

  As this swirling type fine bubble generating device, for example, a water / liquid flow swirl introduction structure in a circular storage chamber of a lower circulation table and a peripheral portion inside a covered cylindrical body gradually expanding upward attached to the upper part thereof The swirling rising water liquid flow forming structure, the swirling falling water liquid flow forming structure formed in the inner part of the peripheral part, and the far-center separation action of the swirling rising water liquid flow and swirling falling water liquid flow The negative pressure swirl cavity formed in the center of the covered cylinder, and the gas swirled from the gas self-priming tube attached to the center of the upper cover into the swirl cavity of the negative pressure are eluted from the swirling water flow. The gas vortex tube is formed as a gas vortex tube that is swirling and falling, and its extension and taper are formed, and the gas vortex tube that is extended and tapered and descends is circular. When turning into the central return port at the bottom of the containment chamber, A fine bubble generation structure that generates a fine bubble by reducing the swirl speed by generating a difference in the swirl speed by receiving the shaft pit of the passage, and the gas vortex tube of the same part is forcibly cut, and the generated fine Examples include a structure in which a bubble is included in a swirling descending water liquid flow and a swirling jet discharge structure is formed such that the swirling jet is discharged from the side discharge port to the outside of the vessel.

  As the swirling fine bubble generating device, for example, a commercially available device such as M2-L type manufactured by Nano Planet Co., Ltd. can be used.

<Liquid composition for inkjet recording>
-Ink-
Next, the ink used in the present invention will be described. The ink used in the present invention contains a coloring material, water, a water-soluble organic solvent, and a surfactant, and may contain other components as necessary.

  The coloring material used in the ink may be either a dye or a pigment, but one or more pigments are particularly preferable. This is considered to be because the pigment is more likely to aggregate when mixed with the treatment liquid than the dye. In particular, since there is a high demand for black images frequently used for characters in offices in recent years, it is preferable to use carbon black, which is a black pigment excellent in water resistance and light resistance of images, for black (black) ink. Among the pigments, a pigment in which the pigment is dispersed with a polymer dispersant, a self-dispersible pigment, and a pigment coated with a resin are preferable.

  As the pigment used in the present invention, either an organic pigment or an inorganic pigment can be used. Examples of the black pigment include carbon black pigments such as furnace black, lamp black, acetylene black, and channel black. In addition to black, cyan, magenta and yellow primary pigments, special color pigments such as red, green, blue, brown and white, metallic luster pigments such as gold and silver, colorless or light body pigments, plastic pigments, etc. May be used. In addition, particles having silica or alumina, polymer beads, or the like as a core, and dyes or pigments fixed on the surface thereof, insoluble lakes of dyes, colored emulsions, colored latexes, and the like can also be used as pigments. Furthermore, a pigment newly synthesized for the present invention may be used.

  Specific examples of the pigment, Raven7000, Raven5750, Raven5250, Raven5000ULTRAII, Raven3500, Raven2500ULTRA, Raven2000, Raven1500, Raven1255, Raven1250, Raven1200, Raven1190ULTRAII, Raven1170, Raven1080ULTRA, Raven1060ULTRA, Raven790ULTRA, Raven780ULTRA, Raven760ULTRA (or, Columbian Carbon Manufactured by Co., Ltd.), Regal 400R, Regal 330R, Regal 660R, Mogu L, Monarch 700, Monarch 800, Monarch 880, Monarch 9 00, Monarch1000, Monarch 1100, Monarch 1300, Monarch 1400 (above, manufactured by Cabot), Color Black FW1, Color Black FW2, Color Black FW2V, Color Black 18, Color Black 150, Color Black , Printex 35, Printex U, Printex V, Printex 140U, Printex 140V, Special Black 6, Special Black 5, Special Black 4A, Special Black 4 25, no. 33, no. 40, no. 47, no. 52, no. 900, no. 2300, MCF-88, MA600, MA7, MA8, MA100 (manufactured by Mitsubishi Chemical Corporation) and the like can be used, but are not limited thereto. As the black pigment, magnetic fine particles such as magnetite and ferrite, titanium black, and the like may be used.

  The pigment that can be self-dispersed in water used in the present invention refers to a pigment that has many water-solubilizing groups on the pigment surface and can be stably dispersed in water without the presence of a polymer dispersant. Specifically, it can be self-dispersed in water by subjecting ordinary so-called pigments to surface modification treatments such as acid / base treatment, coupling agent treatment, polymer graft treatment, plasma treatment, oxidation / reduction treatment, etc. Pigments are obtained.

  Examples of the pigment that can be self-dispersed in water include a pigment obtained by subjecting the above pigment to surface modification treatment, as well as Cab-o-jet-200, Cab-o-jet-250, Cab- o-jet-260, Cab-o-jet-270, Cab-o-jet-300, IJX-444, IJX-55, Microjet Black CW-1, CW-2 manufactured by Orient Chemical Co., and Nippon Shokubai Co., Ltd. Commercially available self-dispersing pigments such as self-dispersing pigments sold by

  Examples of cyan pigments include C.I. I. Pigment Blue-1, -2, -3, -15, -15: 1, -15: 2, -15: 3, -15: 4, -16, -22, -60, and the like. It is not limited.

  Examples of magenta pigments include C.I. I. Pigment Red-5, -7, -12, -48, -48: 1, -57, -112, -122, -123, -146, -168, -184, -202, and the like. It is not limited.

Further, examples of yellow pigments include C.I. I. Pigment Yellow-1, -2, -3, -12, -13, -14, -16, -17, -73, -74, -75, -83, -93, -95, -97, -98, -114, -128, -129, -138, -151, -154, -180, and the like, but are not limited thereto.
Further, as each color material, a so-called capsule dye / pigment in which the color material is encapsulated with various resins may be used.

On the other hand, as the dye used in the present invention, either a water-soluble dye or a disperse dye can be used.
Specific examples of water-soluble dyes include C.I. I. Direct Black-2, -4, -9, -11, -17, -19, -22, -32, -80, -151, -154, -168, -171, -194, -195, C.I. I. Direct Blue-1, -2, -6, -8, -22, -34, -70, -71, -76, -78, -86, -112, -142, -165, -199, -200, -201, -202, -203, -207, -218, -236, -287, -307, C.I. I. Direct Red-1, -2, -4, -8, -9, -11, -13, -15, -20, -28, -31, -33, -37, -39, -51, -59, -62, -63, -73, -75, -80, -81, -83, -87, -90, -94, -95, -99, -101, -110, -189, -227, C.I. I. Direct Yellow-1, -2, -4, -8, -11, -12, -26, -27, -28, -33, -34, -41, -44, -48, -58, -86, -87, -88, -132, -135, -142, -144, -173, C.I. I. Food Black-1, -2, C.I. I. Acid Black-1, -2, -7, -16, -24, -26, -28, -31, -48, -52, -63, -107, -112, -118, -119, -121, -156, -172, -194, -208, C.I. I. Acid Blue-1, -7, -9, -15, -22, -23, -27, -29, -40, -43, -55, -59, -62, -78, -80, -81, -83, -90, -102, -104, -111, -185, -249, -254, C.I. I. Acid Red-1, -4, -8, -13, -14, -15, -18, -21, -26, -35, -37, -52, -110, -144, -180, -249, -257, -289, C.I. I. Acid Yellow-1, -3, -4, -7, -11, -12, -13, -14, -18, -19, -23, -25, -34, -38, -41, -42, -44, -53, -55, -61, -71, -76, -78, -79, -122 and the like.

  Specific examples of the disperse dye include C.I. I. Disperse Yellow-3, -5, -7, -8, -42, -54, -64, -79, -82, -83, -93, -100, -119, -122, -126, -160, -184: 1, -186, -198, -204, -224, C.I. I. Disperse Orange-13, -29, -31: 1, -33, -49, -54, -66, -73, -119, -163, C.I. I. Disperse Red-1, -4, -11, -17, -19, -54, -60, -72, -73, -86, -92, -93, -126, -127, -135, -145, -154, -164, -167: 1, -177, -181, -207, -239, -240, -258, -278, -283, -311, -343, -348, -356, -362, C. I. Disperse Violet-33, C.I. I. Disperse Blue-14, -26, -56, -60, -73, -87, -128, -143, -154, -165, -165: 1, -176, -183, -185, -201,- 214, -224, -257, -287, -354, -365, -368, C.I. I. Disperse Green-6: 1, -9 etc. are mentioned.

  The color material used in the present invention is preferably contained in the range of 1 to 15% by mass, more preferably in the range of 2 to 10% by mass with respect to the total mass of the ink. When the amount of the color material in the ink is less than 1% by mass, a sufficient optical density may not be obtained, and when the amount of the color material is more than 15% by mass, the liquid ejection characteristics are unstable. It may become.

In the present invention, a water-soluble organic solvent is used as a material for improving the moisture retention performance and adjusting the liquid viscosity in the ink.
Examples of the water-soluble organic solvent include polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, polypropylene glycol, butylene glycol, triethylene glycol, 1,5-pentanediol, 1,2,6-hexanetriol, glycerin, Nitrogen-containing solvents such as pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, triethanolamine, alcohols such as ethanol, isopropyl alcohol, butyl alcohol, benzyl alcohol, or thiodiethanol, thiodiglycerol, sulfolane, dimethylsulfur Sulfur-containing solvents such as oxide, propylene carbonate, ethylene carbonate and the like can be used, but are not limited thereto.

  The water-soluble organic solvent used in the present invention may be used alone or in combination of two or more. The water-soluble organic solvent is preferably contained in the range of 1 to 60% by mass, and more preferably in the range of 5 to 40% by mass with respect to the total mass of the ink.

Normally, water is used for the ink, and this water can be ion exchange water, distilled water, pure water, ultrapure water, or the like.
The content of water contained in the ink is preferably in the range of 20 to 80% by mass, particularly in the range of 30 to 60% by mass. If it is less than 20% by mass, the ejection stability may be lowered, and ejection may not be performed normally. Moreover, when it exceeds 80 mass%, it may be inferior in long-term storage stability.

  The liquid viscosity of the ink is preferably in the range of 1 to 15 mPa · s. If the viscosity is less than 1 mPa · s, the thickening on the recording medium may not be sufficient and good image quality may not be obtained, and the ejection stability may be impaired. On the other hand, if it exceeds 15 mPa · s, the ejection stability may not be sufficient, and image omission and blurring may occur.

  In addition, water-soluble resin is added to the ink in order to amplify the effect of improving image density, bleeding, intercolor bleeding, and image uniformity, and to adjust clogging, ejection response / ejection stability, and storage stability. You can also In particular, when the ink contains a water-soluble resin, the effect of improving the image quality is increased. This is because the addition of water-soluble resin assists the networking of the color materials and facilitates the color material to have a three-dimensional structure in the ink. This is presumed to be amplified. In addition, since the network structure can be maintained on the recording medium even after an image is formed by adding a water-soluble resin, an image having excellent fixability and abrasion resistance can be provided.

  As the water-soluble resin, a compound having a hydrophilic structure part and a hydrophobic structure part can be effectively used, and specifically, a condensation polymer and an addition polymer are exemplified. Examples of the condensation polymer include polyester polymers, while addition polymers include addition polymers of monomers having an α, β-ethylenically unsaturated group. In addition, as the addition polymer, for example, a monomer having an α, β-ethylenically unsaturated group having a hydrophilic group and a monomer having an α, β-ethylenically unsaturated group having a hydrophobic group are copolymerized as appropriate. Things are used. Furthermore, a homopolymer of a monomer having an α, β-ethylenically unsaturated group having a hydrophilic group can also be used.

  Examples of the monomer having an α, β-ethylenically unsaturated group having a hydrophilic group include monomers having a carboxyl group, a sulfonic acid group, a hydroxyl group, a phosphoric acid group, such as acrylic acid, methacrylic acid, crotonic acid, and itaconic acid. , Itaconic acid monoester, maleic acid, maleic acid monoester, fumaric acid, fumaric acid monoester, vinyl sulfonic acid, styrene sulfonic acid, sulfonated vinyl naphthalene, vinyl alcohol, acrylamide, methacryloxyethyl phosphate, bismethacryloxyethyl phosphate Methacrylooxyethyl phenyl acid phosphate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate and the like.

  On the other hand, as a monomer having an α, β-ethylenically unsaturated group having a hydrophobic group, styrene derivatives such as styrene, α-methylstyrene, vinyltoluene, vinylcyclohexane, vinylnaphthalene, vinylnaphthalene derivatives, alkyl acrylate esters, Examples include acrylic acid phenyl ester, methacrylic acid alkyl ester, methacrylic acid phenyl ester, methacrylic acid cycloalkyl ester, crotonic acid alkyl ester, itaconic acid dialkyl ester, and maleic acid dialkyl ester.

The copolymer obtained by copolymerizing the monomer having a hydrophilic group and a hydrophobic group may have any structure such as a random, block, and graft copolymer.
Examples of preferred copolymers include styrene-styrene sulfonic acid copolymers, styrene-maleic acid copolymers, styrene-methacrylic acid copolymers, styrene-acrylic acid copolymers, vinyl naphthalene-maleic acid copolymers. , Vinyl naphthalene-methacrylic acid copolymer, vinyl naphthalene-acrylic acid copolymer, alkyl acrylate ester-acrylic acid copolymer, alkyl methacrylate-methacrylic acid, styrene-alkyl methacrylate-methacrylic acid copolymer Styrene-acrylic acid alkyl ester-acrylic acid copolymer, styrene-methacrylic acid phenyl ester-methacrylic acid copolymer, styrene-methacrylic acid cyclohexyl ester-methacrylic acid copolymer, and the like.

  A monomer having a polyoxyethylene group or a hydroxyl group may be appropriately copolymerized with these copolymers. In addition, in order to increase the affinity with the pigment having an acidic functional group on the surface and improve the dispersion stability, a monomer having a cationic functional group such as N, N-dimethylaminoethyl methacrylate, N, N-dimethylamino Ethyl acrylate, N, N-dimethylaminomethacrylamide, N, N-dimethylaminoacrylamide, N-vinylpyrrole, N-vinylpyridine, N-vinylpyrrolidone, N-vinylimidazole, and the like may be copolymerized as appropriate.

  Polystyrene sulfonic acid, polyacrylic acid, polymethacrylic acid, polyvinyl sulfonic acid, polyalginic acid, polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer, formalin condensate of naphthalene sulfonic acid, polyvinyl pyrrolidone, polyethyleneimine, polyamine , Polyamides, polyvinyl imidazoline, aminoalkyl acrylate / acrylamide copolymer, chitosan, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid amide, polyvinyl alcohol, polyacrylamide, carboxymethylcellulose, carboxyethylcellulose Cellulose derivatives such as cellulose, polysaccharides and their derivatives can also be used effectively.

  Although not particularly limited, the hydrophilic group of the water-soluble resin is preferably a carboxylic acid or a salt of a carboxylic acid. This is considered to be because the degree of aggregation of the color material on the recording medium is appropriate particularly when carboxylic acid is used for the hydrophilic group.

Among these water-soluble resins, a copolymer having a hydrophilic group as an acidic group is preferably used in the form of a salt with a basic compound in order to enhance water solubility.
Compounds that form salts with these polymers include alkali metals such as sodium, potassium, and lithium; aliphatic amines such as monomethylamine, dimethylamine, and triethylamine; monomethanolamine, monoethanolamine, diethanolamine, and triethanol Alcohol amines such as amine and diisopropanolamine; ammonia;

  Preferably, basic compounds of alkali metals such as sodium, potassium and lithium are used. This is presumably because alkali metals are strong electrolytes and have the effect of promoting dissociation of hydrophilic groups.

The neutralization amount of the water-soluble resin is more preferably 60% or more neutralized with respect to the acid value of the copolymer, and still more preferably 80% or more of the acid value of the copolymer. It is to be united.
These water-soluble resins may be used alone or in combination of two or more.

  Other inks used in the present invention include cellulose derivatives such as polyethyleneimine, polyamines, polyvinylpyrrolidone, polyethylene glycol, methylcellulose, ethylcellulose, carboxyethylcellulose, glucose, fructose, mannit, D-sorbitol, dextran, xanthan gum, card Polysaccharides such as orchid, cycloamylose and maltitol and derivatives thereof, other polymer emulsions, cyclodextrins, macrocyclic amines, dendrimers, crown ethers, urea and derivatives thereof, acetamide and the like can be used.

  Moreover, you may contain antioxidant, an antifungal agent, a electrically conductive agent, a ultraviolet absorber, a chelating agent etc. as needed. Examples of the chelating agent include ethylenediaminetetraacetic acid (EDTA), iminodiacetic acid (IDA), ethylenediaminedi (o-hydroxyphenylacetic acid) (EDDDHA), nitrilotriacetic acid (NTA), dihydroxyethylglycine (DHEG), trans -1,2-cyclohexanediaminetetraacetic acid (CyDTA), diethylenetriamine-N, N, N ′, N ′, N′-pentaacetic acid (DTPA), glycol ether diamine-N, N, N ′, N′-tetraacetic acid (GEDTA) and the like.

  In addition to these, an electrolyte or a cationic substance may be used to such an extent that a secondary obstacle does not occur. The electrolyte includes alkali metal ions such as lithium ion, sodium ion and potassium ion, and aluminum ion, barium ion, calcium ion, copper ion, iron ion, magnesium ion, manganese ion, nickel ion, tin ion, titanium ion and zinc ion. Etc.

The ink used in the present invention contains a surfactant as a penetrating agent.
As the surfactant, any of nonionic, anionic, cationic, and amphoteric surfactants can be used. Nonionic surfactants include, for example, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan Examples include fatty acid esters, fatty acid alkylolamides, acetylene alcohol ethylene oxide adducts, polyethylene glycol polypropylene glycol block copolymers, glycerin ester polyoxyethylene ethers, sorbitol ester polyoxyethylene ethers, and the like.

  Examples of the anionic surfactant include alkylbenzene sulfonate, alkylphenyl sulfonate, alkyl naphthalene sulfonate, higher fatty acid salts, sulfate esters and sulfonates of higher fatty acid esters, and higher alkyl sulfosuccinates. May be.

  Examples of the cationic surfactant include tetraalkylammonium salts, alkylamine salts, benzalkonium salts, alkylpyridium salts, imidazolium salts, and the like. Examples thereof include dihydroxyethyl stearylamine, 2-heptadecenyl-hydroxyethylimidazoline. Lauryldimethylbenzylammonium chloride, cetylpyridinium chloride, stearamide methylpyridium chloride, and the like.

As the amphoteric surfactant, betaine, sulfobetaine, sulfate betaine, imidazoline and the like can be used. In addition, silicone surfactants such as polysiloxane polyoxyethylene adducts, fluorine surfactants such as oxyethylene perfluoroalkyl ether, biosurfactants such as splicrisporic acid, rhamnolipid, and lysolecithin can also be used.
These surfactants can be used alone or in admixture of two or more. The amount of the surfactant contained in the ink is desirably in the range of 0.001 to 10% by mass in total with respect to the total mass of the ink in consideration of surface tension and wettability.

The ink used in the present invention preferably has a surface tension in the range of 20 to 60 mN / m.
Here, as the surface tension, a value measured in an environment of 23 ° C. and 55% RH using a Wilhelmy surface tension meter (manufactured by Kyowa Interface Science Co., Ltd.) was adopted.

-Treatment liquid-
The treatment liquid used in the present invention contains a component for aggregating and / or thickening the ink, and contains the above-mentioned water, water-soluble organic solvent, and surfactant as basic components, and further agglomerates and concentrates the ink. As the component (flocculating agent) for increasing the viscosity, it can be selected according to the type of the color material contained in the ink.

For an ink containing a colorant having an anionic group on the surface, an electrolyte compound or a cationic compound is preferably used as the ink aggregating agent.
Examples of the electrolyte component of the electrolyte compound include alkali metal ions such as lithium ions, sodium ions, and potassium ions, and aluminum ions, barium ions, calcium ions, copper ions, iron ions, magnesium ions, manganese ions, nickel ions, tin ions, Polyvalent metal ions such as titanium ion, zinc ion, hydrochloric acid, odorous acid, hydroiodic acid, sulfuric acid, nitric acid, phosphoric acid, thiocyanic acid, and acetic acid, oxalic acid, lactic acid, fumaric acid, fumaric acid, citric acid, Examples thereof include organic carboxylic acids such as salicylic acid and benzoic acid, and organic sulfonic acid salts.

  Specific examples of the ink aggregating agent containing the electrolyte listed above include lithium chloride, sodium chloride, potassium chloride, sodium bromide, potassium bromide, sodium iodide, potassium iodide, sodium sulfate, potassium nitrate, sodium acetate, and oxalic acid. Salts of alkali metals such as potassium, sodium citrate, potassium benzoate, and aluminum chloride, aluminum bromide, aluminum sulfate, aluminum nitrate, sodium aluminum sulfate, potassium aluminum sulfate, aluminum acetate, barium chloride, barium bromide, Barium iodide, barium oxide, barium nitrate, barium thioanate, calcium chloride, calcium bromide, calcium iodide, calcium nitrite, calcium nitrate, calcium dihydrogen phosphate, calcium thiocyanate, benzoic acid Calcium, calcium acetate, calcium salicylate, calcium tartrate, calcium lactate, calcium fumarate, calcium citrate, copper chloride, copper bromide, copper sulfate, copper nitrate, copper acetate, iron chloride, iron bromide, iron iodide, sulfuric acid Iron, iron nitrate, iron oxalate, iron lactate, iron fumarate, iron citrate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium sulfate, magnesium nitrate, magnesium acetate, magnesium lactate, manganese chloride, manganese sulfate, manganese nitrate , Manganese dihydrogen phosphate, manganese acetate, manganese salicylate, manganese benzoate, manganese lactate, nickel chloride, nickel bromide, nickel sulfate, nickel nitrate, nickel acetate, tin sulfate, titanium chloride, zinc chloride, zinc bromide, sulfuric acid Zinc, zinc nitrate, zinc thiocyanate, zinc acetate, etc. Salts of polyvalent metals, and the like.

On the other hand, examples of the cationic compound include primary, secondary, tertiary and quaternary amines and salts thereof.
Specific examples of the ink aggregating agent made of the cationic compound include tetraalkylammonium salts, alkylamine salts, benzalkonium salts, alkylpyridium salts, imidazolium salts, polyamines, and the like. For example, isopropylamine, isobutyl Amine, t-butylamine, 2-ethylhexylamine, nonylamine, dipropylamine, diethylamine, trimethylamine, triethylamine, dimethylpropylamine, ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, tetraethylenepentamine, diethanolamine, diethylethanolamine, triethylamine Ethanolamine, tetramethylammonium chloride, tetraethylammonium bromide, dihydroxyethylstearyl Min, 2-heptadecenyl - hydroxyethyl imidazoline, lauryl dimethyl benzyl ammonium chloride, cetyl pyridinium chloride, stearamide methyl pyridinium chloride, diallyldimethylammonium chloride polymers, diallylamine polymers include monoallylamine polymer and the like.

  Among the ink flocculants listed above, more preferable are aluminum sulfate, calcium chloride, calcium nitrate, calcium acetate, magnesium chloride, magnesium nitrate, magnesium sulfate, magnesium acetate, tin sulfate, zinc chloride, zinc nitrate. Zinc sulfate, zinc acetate, aluminum nitrate, monoallylamine polymer, diallylamine polymer, diallyldimethylammonium chloride polymer, and the like.

On the other hand, for an ink containing a colorant having a cationic group on the surface, it is preferable to use an anionic compound or the like as the ink aggregating agent.
Examples of the anionic compound include organic carboxylic acids or organic sulfonic acids, and salts thereof. Specific examples of the organic carboxylic acid include acetic acid, succinic acid, lactic acid, fumaric acid, citric acid, salicylic acid, benzoic acid, and the like, and an oligomer or polymer having a plurality of these basic structures may be used. Examples of the organic sulfonic acid include compounds such as benzenesulfonic acid and toluenesulfonic acid, and an oligomer or polymer having a plurality of these basic structures may be used.

  Only one type of ink flocculant contained in the ink flocculant may be used, but two or more types may be used. Further, the content of the ink aggregating agent in the ink aggregating liquid is preferably in the range of 0.1 to 15% by mass, and more preferably in the range of 0.5 to 10% by mass.

In addition, the treatment liquid used in the present invention may contain one or more of a water-soluble polymer, a water-soluble oligomer, a resin emulsion, and an inorganic oxide.
Examples of the resin emulsion include acrylic resins, vinyl acetate resins, styrene-butadiene resins, acrylic-styrene resins, butadiene resins, styrene resins, polyurethane resins, polyolefin resins, polyester resins, polyamide resins. , Melamine resin, urea resin, silicone resin, fluorine resin, polybutene resin, and various waxes. Examples of commercially available emulsions include Boncoat 4001 (acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), Boncoat 5454 (styrene-acrylic resin emulsion, manufactured by Dainippon Ink & Chemicals, Inc.), J-74J. , J-734 (manufactured by Jonkrill Co., Ltd.) and the like, but are not limited thereto.

  The resin emulsion may be prepared by mechanically refining or dispersing a resin or wax in an aqueous medium, or directly polymerizing fine particles by emulsion polymerization, dispersion polymerization or suspension polymerization. In a preferred embodiment of the present invention, these resins are desirably polymers having both a hydrophilic part and a hydrophobic part. The particle shape may be spherical or any other shape. In the case of emulsion polymerization, either an emulsifier or soap-free may be used.

Examples of the inorganic oxide include, but are not limited to, high molecular weight silicic acid anhydride (SiO ₂ ) and alumina (Al ₂ O ₃ ).

  The volume average particle size of these resin emulsions or inorganic oxide colloids is preferably in the range of 10 nm to 2 μm, more preferably in the range of 50 to 500 nm. When the volume average particle diameter is larger than 2 μm, problems are likely to occur in the discharge stability of the processing liquid and the stability during standing. On the other hand, if it is smaller than 10 nm, problems such as leaving recovery of the nozzle are likely to occur.

  Moreover, the addition amount is preferably 0.1% by mass or more and 10% by mass or less in terms of solid content in the treatment liquid. If it is less than 0.1% by mass, there is a case where the density of the printed matter is not improved and the density is also lowered. When the amount exceeds 10% by mass, the ejection stability may be lowered or the image drying property may be deteriorated.

  Further, the treatment liquid may be used as a colorless transparent liquid, or may be used as, for example, a color ink containing a coloring material. In the latter case, it is preferable that the treatment liquid further contains the same color material as described above. The colorant contained in the treatment liquid is preferably a pigment as in the case of the ink.

  When the colorant is included in the treatment liquid, the colorant is preferably contained in the range of 1 to 15% by mass, and preferably in the range of 2 to 10% by mass with respect to the total mass of the treatment liquid. More preferred.

Moreover, it is preferable that the surface tension of the process liquid in this invention is the range of 20-40 mN / m. In such a range, the image drying time is fast and it is easy to realize both image quality effects.
The surface tension was measured under the environment of 23 ° C. and 55% RH using a Wilhelmy surface tension meter as described above.

<Anti-mold and antibacterial properties in ink-jet recording devices using catalysts>
In the ink jet recording apparatus, in addition to the liquid composition for ink jet recording, various troubles may occur due to mold and bacterial contamination at various places in the ink jet recording apparatus. Such troubles include, for example, image deterioration in the vicinity of the nozzle, deterioration of reliability due to nozzle clogging, etc., and may cause odor in the waste liquid recovery part of the liquid composition for ink jet recording. , May become a hotbed of mold and bacteria. In addition, the liquid composition for ink jet recording stored in the storage container can be handled by the fine bubble processing as described above. For example, the inside and outside of the storage container are communicated to adjust the atmospheric pressure in the storage container. It is also conceivable that mold or the like is generated around the communication hole provided.

  Further, the problems described above are likely to be manifested in large machines used for high-speed and large-volume image formation. This is because large machines are used for a relatively long period of time, have a large capacity storage container for ink-jet recording liquid composition, have a large amount of waste liquid generated due to image formation, etc. This is because air outside the apparatus is taken into the apparatus by devising an air flow or an air flow path for the purpose.

On the other hand, photocatalysts such as titanium oxide are generally known as one of representative substances having antibacterial and antifungal effects. However, the place where the trouble as described above occurs is in the ink jet recording; that is, the place where the light does not hit.
In view of this point, the present inventors have considered that it is important to use a catalytic effect such as antibacterial and antifungal properties without irradiation with visible light or ultraviolet light. Examples of such a catalyst material include a metal salt containing a metal element selected from Ti, Zr, Hf, and Ce. The metal element constituting the metal salt is preferably Ti, and the metal salt is preferably a phosphate salt.

In addition to the above metal salt, a catalyst containing an iron compound, an aluminum compound, a potassium compound, and a titanium compound (for example, Cefir manufactured by Nichirin Chemical Co., Ltd.) is also included.
In this catalyst, the potassium compound potassium 40 acts on water molecules in the air to generate hydroxyl radicals (.OH) and hydrogen peroxide. Hydroxyl radicals are generated from hydrogen peroxide by the Fenton reaction in which transition elements such as iron and titanium in SELPHYL act. Also, superoxide ions (O ₂ ⁻ ) are generated by a reaction using hydroperoxy radicals (.OOH) generated from hydrogen peroxide and oxygen in the air as raw materials, and these superoxide ions also contribute to the decomposition reaction. Such oxidizing power is effective against bacteria and mold, and this reaction can kill bacteria and suppress mold growth.

  The catalyst can be provided at any location in the ink jet recording apparatus, and examples thereof include a nozzle part, a nozzle peripheral part, a recording head maintenance part (for example, a wiper blade, a channel, an absorber, etc.).

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited only to the Example shown below.

<Ink A1>
Ink A1 is composed of the following composition, and has a pH of 7.4, a surface tension of 32.5 mN / m, and a viscosity of 3.2 mPa · s.
・ Pigment dispersion (Cabojet-300, manufactured by Cabot) 4% by mass
・ Water-soluble organic solvent (diethylene glycol) 25% by mass
・ Surfactant (acetylene glycol ethylene oxide adduct) 0.2% by mass
・ Ion exchange water balance

<Ink A2>
Ink A2 is composed of the following composition, and has a pH of 7.9, a surface tension of 33 mN / m, and a viscosity of 4.3 mPa · s.
・ Pigment dispersion (Cabojet-300, manufactured by Cabot) 4% by mass
・ Water-soluble organic solvent (diethylene glycol) 25% by mass
・ Surfactant (acetylene glycol ethylene oxide adduct) 0.2% by mass
Antifungal agent (1,2 benzoisothiazolin-3-one) 0.2% by mass
・ Ion exchange water balance

<< Ink manufacturing >>
(Example A1)
Ink A1 was produced by the following procedure.
First, the pigment dispersion was treated at 7000 rpm for 30 min using a centrifugal separator (SS-2000, manufactured by Sakuma Seisakusho Co., Ltd.), the precipitate was removed, and this was used as a raw material for liquid mixture adjustment.
Next, by using the fine bubble treatment apparatus 100 shown in FIG. 1, the pigment dispersion, the water-soluble organic solvent, the surfactant, and the ion exchange water were sufficiently mixed and the fine bubble treatment was performed. Note that the container 130 of the microbubble processing apparatus 100 used in this example is a SUS tank having a bottom size of 20 cm × 30 cm and a height of 30 cm, and microbubbles are generated near the center of the bottom surface of the tank. As the device 120, an M2-MS type manufactured by Nano Planet Co., Ltd. is arranged. Air is supplied from the gas supply pipe 126 to the fine bubble generator 120.
Here, 2 L of the mixture obtained by supplying the pigment dispersion, water-soluble organic solvent, surfactant, and ion-exchanged water into the tank is slowly stirred with a propeller having a diameter of 30 mm so as not to generate bubbles. Then, the liquid mixture containing fine bubbles was discharged from the fine bubble generator under the following conditions into the tank for 1 min, and the mixture was treated with fine bubbles. The water depth from the liquid level to the discharge port of the fine bubble generator was about 30 cm.

-Driving conditions of microbubble generator-
・ Pressure: 0.2 MPa
・ Flow rate: 15L / min
・ Swivel speed: 500 revolutions per second Note that, under the same conditions as described above, the microbubble generator is driven using air and pure water, and the liquid containing the microbubbles discharged from the vicinity of the discharge port of the apparatus is scanned with a high-speed camera ( About 100 bubbles were measured at random for the fine bubbles reflected in the photograph obtained by FASTCAM-APX RS (manufactured by Photolon), and the average diameter was about 35 μm.

  Next, the mixed liquid after the mixing and fine bubble treatment was filtered through a filter (membrane filter, manufactured by Millipore, opening 5 μm, material: PVDF) to obtain ink 1.

(Example A2)
Ink A1 was obtained in the same manner as in Example A1, except that the microbubble treatment time was changed to 5 minutes.

(Example A3)
Ink A1 was obtained in the same manner as in Example A1, except that the microbubble treatment time was changed to 10 minutes.

(Example A4)
Other than changing the microbubble treatment time to 5 minutes and applying an ultrasonic wave with an output of 200 W to the mixed solution after the filtration step for 5 minutes with an ultrasonic generator (SI-18TH, SU-18TH) In the same manner as in Example 1, an ink 1 was obtained.

(Comparative Example A1)
Ink 1 was obtained in the same manner as in Example A1, except that the fine bubble treatment was not performed in Example A1.

(Comparative Example A2)
Ink A2 instead of ink A1 was prepared by mixing, treating fine bubbles and filtering under the same conditions as in Comparative Example A1.

<Evaluation>
The obtained ink was evaluated for continuous jetting stability, storage stability, and antifungal property. The results are shown in Table 1.

  In addition, the continuous injection stability shown in Table 1, storage stability, and the evaluation method and evaluation criteria of antifungal property are as follows.

<Continuous injection stability>
A prototype recording head (thermal head with a resolution of 600 dpi, 256 nozzles and a heat generating element) was filled with ink prepared by the procedure shown in each example and comparative example (2 heads), and 10 8 times continuous. After jetting, the landing accuracy (J6 pattern by batch: JEITA standard pattern print deterioration degree) was visually evaluated. The evaluation criteria are as follows.
○: Lines cannot be confirmed △: Lines are missing but not noticeable ×: Many lines are missing

<Storage stability evaluation>
Prototype recording head (resolution 600 dpi, 256 nozzles, thermal head with built-in heating element) filled with ink prepared in the procedure shown in each example and comparative example (: 8 heads), and then around the nozzle surface is silicon resin And then left for 2 weeks (in a room temperature 23 ° C./humidity 55% environment).
Then, after being left for 2 weeks, ink was ejected from the nozzles, and a 256 line pattern of 1 nozzle: 100 dots at a time was printed and visually observed to evaluate the degree of nozzle clogging. The evaluation criteria are as follows.
○: 100% discharge rate
Δ: 90% <Discharge rate <100%
×: Discharge rate <90%
The discharge rate is a value represented by the observed number of lines / 256 lines (the number of lines when the discharge rate is 100%, corresponding to the total number of nozzles (256 nozzles)).

<Anti-mold evaluation>
In a plastic petri dish, 2 ml of the ink prepared according to the procedure shown in each example and comparative example was put, covered, and stored at a temperature of 28 ± 2 ° C. and a humidity of about 97%. After 4 weeks, the state of occurrence of mold mycelia and the like was observed visually and with a microscope. The evaluation criteria are as follows.
○: No mold occurred.
Δ: Mold generation is less than 1/4 of the total area.
(Same result as no change in ink cartridge for 2 years, no problem in practical use)
X: Mold generation is ¼ or more of the total area. Actually unusable.

<< Inkjet recording apparatus >>
-Inkjet recording device-
In the evaluation, 1) an apparatus including a thermal recording head as a recording head (hereinafter, may be referred to as “apparatus S1”) in the ink jet recording apparatus having a configuration shown in FIG. 2 is a device provided with a piezo-type recording head in the ink jet recording apparatus having the configuration shown in FIG. 2 (hereinafter may be referred to as “device P1”). 3) Ink jet recording having the main portion having the configuration shown in FIG. Four types of apparatuses (hereinafter, referred to as “apparatus SN” in some cases) were prepared by removing the fine bubble generating apparatus and the ultrasonic wave application means from the apparatus and having a thermal recording head.
These apparatuses are modified machines obtained by modifying a commercially available inkjet recording apparatus (Work Center B900 manufactured by Fuji Xerox Co., Ltd.). In the test, the inside of the tank and the like was thoroughly cleaned in advance.

Next, the configuration of the main part of these devices S1, P1, and SN will be described.
(1) Storage container The tank used as the storage container is a box-shaped PET container having a bottom size of 10 cm × 20 cm and a height of 20 cm. In the evaluation, 2 L of ink was filled.

(2) Microbubble generator M2-L type manufactured by Nano Planet Co., Ltd. was used as the microbubble generator 120 used in the devices S1 and P1. The evaluation was performed under the following conditions.
-Driving conditions of microbubble generator-
・ Pressure: 0.2 MPa
・ Flow rate: 15L / min
・ Swivel speed: 500 revolutions per second Note that the microbubble generator is driven using air and pure water under the same conditions as described above, and the liquid containing the microbubbles discharged from the vicinity of the discharge port of the apparatus is obtained with a high-speed camera. When about 100 diameters of the fine bubbles in the photograph obtained by photographing were measured at random, the average diameter was about 35 μm.

(3) Ultrasonic wave generation means As the ultrasonic wave generation means used in the devices S1 and P1, TBL4535D-40 (oscillator: bolt-clamped Rush vane vibrator) manufactured by Tamura Seisakusho was attached to the center of the tank bottom. Used in state. In the evaluation, ultrasonic waves were applied at an output of 70 W and an oscillation frequency of 40 kHz.

(3) Thermal recording head A prototype recording head (resolution 600 dpi, 256 nozzles) was used as the thermal recording head used in the devices S1 and SN.

(4) Piezo-type recording head As the piezo-type recording head used in the apparatus P1, a prototype recording head (resolution 600 dpi, 256 nozzles) was used.

-Ink-
For the evaluation, ink (ink B1) prepared by the procedure shown in Comparative Example A1 and ink (ink B2) prepared by the procedure shown in Comparative Example A2 were prepared.

<Example B1>
After filling the tank of the apparatus S1 with the ink B1, the fine bubble generating device was driven for 1 minute to process the fine bubbles in the ink in the tank.
Subsequently, continuous injection stability and storage stability were evaluated about 10 minutes after the microbubble treatment. In addition, after the fine bubble treatment, the tank was allowed to stand for 4 weeks in an environment of 28 ° C. and 97% RH to evaluate the antifungal property.

<Example B2>
In Example B1, evaluation was performed in the same manner as in Example B1, except that the microbubble treatment time was changed to 5 min.

<Example B3>
In Example B1, ultrasonic waves were applied for 5 minutes after the microbubble treatment, and continuous injection stability and storage stability were evaluated about 10 minutes after the application of ultrasonic waves. Further, after applying the ultrasonic wave, the tank was allowed to stand in an environment of 28 ° C. and 97% RH for 4 weeks to evaluate the antifungal property.

<Example B4>
In Example B1, evaluation was performed in the same manner as in Example B1, except that the device P1 was used instead of the device S1.

<Example B5>
In Example B2, evaluation was performed in the same manner as in Example B2, except that the device P1 was used instead of the device S1.

<Example B6>
In Example B3, evaluation was performed in the same manner as in Example B3, except that the device P1 was used instead of the device S1.

<Comparative Example B1>
After filling the tank of the apparatus S1 with the ink B1, the continuous ejection stability and the storage stability were evaluated. Further, the mold was allowed to stand for 4 weeks in an environment of 28 ° C. and 97% RH to evaluate the antifungal property.

<Comparative Example B2>
In Comparative Example B1, evaluation was performed in the same manner as Comparative Example B1, except that ink B2 was used instead of ink B1.

  The results of Examples and Comparative Examples shown above are shown in Table 2 below.

  The evaluation methods and evaluation criteria for continuous injection stability, storage stability, and antifungal properties shown in Table 2 are as follows.

<Continuous injection stability>
Filled with ink prepared by the procedure shown in each example and comparative example (: 2 heads), and visually evaluated landing accuracy (deterioration degree of J6 pattern: JEITA standard pattern) after 10 8 times continuous ejection did. The evaluation criteria are as follows.
○: Lines cannot be confirmed △: Lines are missing but not noticeable ×: Many lines are missing

<Storage stability>
After filling with ink prepared by the procedure shown in each example and comparative example (: 8 heads), the nozzle surface was capped with a silicone resin cap for 2 weeks (room temperature 23 ° C./humidity 55% environment) )did.
Then, after being left for 2 weeks, ink was ejected from the nozzles, and a 256 line pattern of 1 nozzle: 100 dots at a time was printed and visually observed to evaluate the degree of nozzle clogging. The evaluation criteria are as follows.
○: 100% discharge rate
Δ: 90% <Discharge rate <100%
×: Discharge rate <90%
The discharge rate is a value represented by the observed number of lines / 256 lines (the number of lines when the discharge rate is 100%, corresponding to the total number of nozzles (256 nozzles)).

<Anti-mold property>
After completion of the standing, the state of occurrence of mold mycelium and the like was observed visually and with a microscope. The evaluation criteria are as follows.
○: No mold occurred.
Δ: Mold generation is less than 1/4 of the total area.
(Same result as no change in ink cartridge for 2 years, no problem in practical use)
X: Mold generation is ¼ or more of the total area. Actually unusable.

It is a schematic diagram which shows an example of the fine bubble processing apparatus used for a fine bubble process. 1 is a schematic diagram illustrating a configuration example of an ink jet recording apparatus of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Fine bubble processing apparatus 110 1st raw material supply pipe 112 2nd raw material supply pipe 120 Fine bubble generation apparatus 122 Liquid supply pipe 124 Pump 126 Gas supply pipe 130 Container 140 Mixed liquid 200 Inkjet recording apparatus 210 Droplet discharge means 220 Fine Bubble generator 230 Ultrasonic application means 240 Recovery unit 250 252, 254 Pump 260 Filter 270 Supply pipe 272 (undischarged liquid) Recovery pipe 274 (discharge liquid) Recovery pipe 274 Storage container 276 Circulation pipe 278 Gas supply pipe 280 Storage container 290 Liquid composition for inkjet recording

Claims (9)

At least a mixed liquid preparation step of preparing a mixed liquid in which a pigment dispersion, a water-soluble organic solvent, a surfactant, and water are mixed;
A method for producing a liquid composition for ink jet recording, comprising: supplying fine bubbles to at least one liquid selected from the pigment dispersion and the mixed liquid. At least a mixed liquid preparation step of preparing a mixed liquid obtained by mixing a flocculant that promotes aggregation of the pigment contained in the ink, a water-soluble organic solvent, a surfactant, and water;
A method for producing a liquid composition for ink jet recording, wherein the mixed liquid is processed by supplying fine bubbles.   The liquid for inkjet recording according to claim 1, further comprising a degassing step of degassing a gas component dissolved in the liquid mixture by applying an ultrasonic wave to the liquid mixture. A method for producing the composition. A storage container for storing a liquid composition for inkjet recording;
A droplet discharge means that includes at least a droplet discharge surface and a nozzle disposed on the droplet discharge surface, and discharges the inkjet recording liquid composition from the nozzle in the form of droplets;
A supply pipe for transferring the liquid composition for inkjet recording from the storage container to the droplet discharge means;
A fine bubble generator for supplying fine bubbles into the storage container;
An ink jet recording apparatus comprising:   The inkjet recording apparatus according to claim 4, further comprising an ultrasonic wave application unit that applies ultrasonic waves to the liquid composition for inkjet recording stored in the storage container.   6. The ink jet recording apparatus according to claim 5, wherein the droplet discharge means includes a heating element that heats the liquid flowing in the nozzle.   A recovery section for recovering the ink jet recording liquid composition discharged from the droplet discharge means; and a recovery pipe for transferring the recovered ink jet recording liquid composition from the recovery section to the storage container. The ink jet recording apparatus according to claim 4, further comprising: Capacity of the storage container, an ink jet recording apparatus according to any one of claims 4-7, characterized in that in the range of 500 cm ³ or more 5000 cm ³ or less.   The ink jet recording apparatus according to claim 5, wherein the liquid composition for ink jet recording is an ink containing a pigment.

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