JP5713736B2 - Ink filling method - Google Patents

Description

  The present invention provides an ink jet recording apparatus using an ink for an ink jet recording apparatus having a polyhydric alcohol monoalkyl ether content of 10% by mass to 25% by mass with respect to the mass of the ink. It is related with the inkjet head preservation | save liquid with which an inkjet head is beforehand filled before is filled.

  Ink jet heads used in image forming apparatuses of the ink jet recording method are roughly classified into a thermal method and a piezo method, and a continuous ejection type printer includes an electrostatic method in which discharged ink droplets are controlled by an electric field. In the thermal method, the heater is heated instantaneously and bubbles are generated. Ink droplets are ejected using this force. In the piezo method, an ink droplet is ejected by applying a force to ink by vibrating a piezoelectric element.

  As a method of applying force to ink by a piezo method, there are a method of applying force to ink with a piezoelectric element that vibrates vertically and a method of applying force to ink with a piezoelectric element that flexibly vibrates. In order to achieve high pixel density and mass productivity, it is better to use a piezoelectric element that bends and vibrates, and it is better not to use lamination. Therefore, since there is a limit to the force applied to the ink, it is necessary to minimize the loss of the pressure wave generated by the vibration and efficiently transmit the force to the nozzle portion.

  Ink jet recording type image forming apparatuses do not cause clogging of ink in the nozzle section or ink flow path, can perform stable ejection, and can record sufficiently high density with clear color tone (hereinafter referred to as ink for ink jet recording apparatus) , Also simply referred to as ink). In addition, for the purpose of forming an image at high speed without causing an offset, polyhydric alcohol monoalkyl ether, which is a component that enhances the permeability of ink into a recording medium (paper, etc.), is used with respect to the mass of the ink. Inks containing 10% by mass to 25% by mass have been proposed.

  And in order to fully demonstrate the performance of such ink, especially when using a piezo ink jet head, it is necessary to minimize the loss of pressure waves generated by vibration and efficiently transmit force to the nozzle part. In addition, it is necessary to completely fill the ink jet head with ink without generating bubbles.

  For this reason, by pre-filling the inkjet head of the image forming apparatus, as an introduction liquid (inkjet head storage liquid) for completely filling the ink without generating bubbles, the liquid just after foaming by the Ross Miles method is used. An introduction liquid having a foam height of 2 mm or less and a foam height of 0 mm after 5 minutes and containing water and a water-soluble organic solvent having surface activity and lower volatility than water has been proposed (patent document) 1).

JP 2000-094707 A

  However, since the ink jet head is formed of various members, and there are minute steps or gaps in the bonding portion of the members constituting the ink jet head, when the introduction liquid described in Patent Document 1 is filled in the ink jet head In addition, bubbles may remain in the ink flow path. In addition, since the introduction liquid described in Patent Document 1 has insufficient compatibility with an ink in which the content of the polyhydric alcohol monoalkyl ether is 10% by mass or more and 25% by mass or less with respect to the mass of the ink, the inkjet liquid is used. In some cases, the introduced liquid in the head cannot be completely replaced with ink. For this reason, when an ink jet head is filled with the introduction liquid disclosed in Patent Document 1, ink ejection may not be stable and the image density may decrease.

  Furthermore, the introduction liquid described in Patent Document 1 is easily frozen. For this reason, when the image forming apparatus is stored or circulated in a cold region with the introduction liquid filled in the inkjet head, the volume of the introduction liquid in the inkjet head due to freezing causes the inkjet head to change. Problems may occur.

  The present invention has been made in view of such circumstances, and it is difficult to generate bubbles when filling an inkjet head, and can easily be replaced with ink in the inkjet head, and is difficult to freeze even in a cold region. In an ink jet recording apparatus using an ink having an alcohol monoalkyl ether content of 10% by mass or more and 25% by mass or less based on the mass of the ink, before the ink is filled in the ink jet head, the ink jet previously filled in the ink jet head It is an object to provide a head preservation solution.

  In the inkjet head preservation solution containing water, a surfactant, a dissolution stabilizer, and a polyhydric alcohol, the inventors set the content of the polyhydric alcohol to 35% by mass or more based on the mass of the inkjet head preservation solution. It has been found that the above-mentioned problems can be solved by setting the content to 70% by mass or less, and the present invention has been completed. Specifically, the present invention provides the following.

(1) In an ink jet recording apparatus using an ink for an ink jet recording apparatus having a polyhydric alcohol monoalkyl ether content of 10% by mass or more and 25% by mass or less with respect to the mass of the ink, An ink-jet head storage solution that is pre-filled into an ink-jet head before being filled,
Containing at least water, a surfactant, a dissolution stabilizer, and a polyhydric alcohol,
The inkjet head preservation | save liquid whose content of the said polyhydric alcohol is 35 mass% or more and 70 mass% or less with respect to the mass of the said inkjet head preservation | save liquid.

  (2) The inkjet head preservation | save liquid of (1) description whose content of the said surfactant is 1 mass% or more and 3 mass% or less with respect to the mass of the said inkjet head preservation | save liquid.

  (3) The ink-jet head preservation solution according to (1) or (2), wherein the polyhydric alcohol is a mixture of alkylene glycol and glycerin.

  (4) The inkjet head preservation | save liquid of (3) description whose content of glycerol in the mixture of the said alkylene glycol and glycerol is 20 mass% or more and 90 mass% or less.

  (5) The inkjet head preservation solution according to any one of (1) to (4), which does not freeze at −20 ° C.

  According to the present invention, the ink has a polyhydric alcohol monoalkyl ether content that is less likely to generate bubbles when filled in the ink jet head, can be easily replaced with ink in the ink jet head, and is not easily frozen even in cold regions. In the ink jet recording apparatus using 10% by mass or more and 25% by mass or less of the ink with respect to the mass of the ink jet ink, it is possible to provide an ink jet head preserving liquid that is filled in the ink jet head in advance before the ink jet head is filled with the ink. .

It is a top view of an inkjet head. It is an enlarged view showing a head structure per dot in an ink jet head.

  Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the object of the present invention. In addition, although description may be abbreviate | omitted suitably about the location where description overlaps, the summary of invention is not limited.

  An ink jet recording apparatus using the ink having a polyhydric alcohol monoalkyl ether content of 10% by mass or more and 25% by mass or less with respect to the mass of the ink is used as an ink jet head storage liquid (hereinafter also simply referred to as a storage liquid) of the present invention. An ink-jet head preserving solution that is pre-filled in the ink-jet head before the ink-jet head is filled with ink. Hereinafter, the ink-jet head preservation liquid of the present invention, the ink for an ink-jet recording apparatus used in the image forming apparatus using the ink-jet head preservation liquid of the present invention, and the ink-jet head filled with the recording liquid of the present invention will be described in order.

[Preservation solution]
The ink jet head preservation liquid of the present invention is an ink jet head preservation liquid containing at least water, a surfactant, a dissolution stabilizer, and a polyhydric alcohol, and the content of the polyhydric alcohol is the mass of the ink jet head preservation liquid. It is 35 mass% or more and 70 mass% or less with respect to. Hereinafter, water, a surfactant, a dissolution stabilizer and a polyhydric alcohol, which are essential components of the ink jet head preservation liquid of the present invention, and a method for producing the ink jet head preservation liquid will be described in order.

〔water〕
The ink-jet head preservation solution of the present invention essentially contains water. The water contained in the preservation solution is not particularly limited as long as the object of the present invention is not impaired, and water having a desired purity can be appropriately selected from water conventionally used for the production of water-based inks. As water used for the preservation solution, for example, ion exchange water is preferably used. The water content in the preservation solution of the present invention is not particularly limited as long as the object of the present invention is not impaired. The content of water is appropriately changed according to the amount of other components to be described later. The typical water content in the preservation solution is preferably 10% by mass or more and 60% by mass or less, and more preferably 20% by mass or more and 40% by mass or less, based on the total mass of the preservation solution.

[Surfactant]
The ink jet head preservation solution of the present invention essentially contains a surfactant. When the preservation solution contains a surfactant, the surface tension of the preservation solution is lowered, and bubbles are less likely to be generated when the preservation solution is filled in the ink jet head.

  The surfactant to be contained in the preservation solution is not particularly limited as long as the object of the present invention is not impaired, and is at least one selected from the group consisting of a cationic surfactant, an anionic surfactant, and a nonionic surfactant. Seeds can be used. Among these surfactants, anionic surfactants or nonionic surfactants are more preferable.

  Specific examples of the cationic surfactant include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide and the like. Specific examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, and sulfonates such as sodium dodecyl sulfate and sodium dodecylbenzene sulfonate. Specific examples of nonionic surfactants include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl sucrose, and ethylene oxide of acetylenic diol. Examples include adducts. These surfactants can be used in combination of two or more.

  The content of the surfactant in the preservation solution is not particularly limited as long as the object of the present invention is not impaired. The content of the surfactant is 1% by mass or more with respect to the total mass of the preservation solution because the preservation solution is excellent in substitution with the ink and the surfactant is not easily released from the preservation solution during storage. The mass% or less is preferable.

[Dissolution stabilizer]
The ink jet head preservation solution of the present invention essentially contains a dissolution stabilizer as a component that stabilizes the uniform dissolution state of the ink jet head preservation solution. Specific examples of the dissolution stabilizer include 2-pyrrolidone, N-methyl-2-pyrrolidone, and γ-butyrolactone. These dissolution stabilizers can be used in combination of two or more. The content of the dissolution stabilizer in the ink-jet head preservation solution is not particularly limited as long as it does not impair the object of the present invention, but is preferably 1% by mass or more and 20% by mass or less with respect to the mass of the ink-jet head preservation solution. More preferred is 15% by mass or less.

[Polyhydric alcohol]
The preservation | save liquid of this invention contains 35 mass% or more and 70 mass% or less of polyhydric alcohol essential with respect to the mass of a preservation | save liquid, More preferably, it is 45 mass% or more and 70 mass% or less. When the preserving liquid contains such an amount of polyhydric alcohol, the surface length tension of the preserving liquid is reduced, and bubbles are less likely to be generated when the preserving liquid is filled in the ink jet head. Further, since the storage solution contains such an amount of polyhydric alcohol, the content of the polyhydric alcohol monoalkyl ether is compatible with the ink for an ink jet recording apparatus having 10 mass% or more and 25 mass% or less with respect to the mass of the ink. In this case, the storage solution can be easily replaced with ink in the ink jet head. Furthermore, when the preservation solution contains such an amount of polyhydric alcohol, the preservation solution becomes difficult to freeze at, for example, −20 ° C., and the occurrence of problems of the ink jet head due to the freezing of the preservation solution is suppressed.

  The type of polyhydric alcohol contained in the preservation solution is not particularly limited as long as the object of the present invention is not impaired. Specific examples of the polyhydric alcohol include polyethylene glycol, diethylene glycol, triethylene glycol and other oligos or polyethylene glycol; polypropylene glycol, dipropylene glycol, tripropylene glycol and other oligos or polypropylene glycol; ethylene glycol, propylene glycol, butylene glycol, Alkylene glycols such as 1,3-butanediol and 1,5-pentanediol; alkanetriols such as 1,2,6-hexanetriol; thiodiglycol; glycerin. These polyhydric alcohols can be used in combination of two or more.

  Among these polyhydric alcohols, ethylene glycol, propylene glycol, butylene glycol, 1,3-butanediol, 1 are excellent in affinity with ink and easy to prepare a storage solution having a suitable viscosity. More preferably, a mixture of alkylene glycol such as 1,5-pentanediol and glycerin is used. When using the mixture of alkylene glycol and glycerol, 20 mass% or more and 90 mass% or less are preferable, and, as for content of glycerol in a mixture, 30 mass% or more and 80 mass% or less are more preferable.

[Method for producing inkjet head preservation solution]
The method for producing the inkjet head preservation solution of the present invention is not particularly limited as long as the components of the preservation solution can be mixed uniformly. Specific examples of the method for producing the preservation solution include a method in which the components of the preservation solution are uniformly mixed with a mixer and then foreign matters and coarse particles are removed with a filter having a pore size of 10 μm or less. In addition, when manufacturing a preservation | save liquid, various additives, such as antioxidant, a viscosity adjuster, a pH adjuster, and antiseptic | preservative antifungal agent, can be added as needed.

[Ink for inkjet recording apparatus]
An ink jet recording apparatus using an ink for an ink jet recording apparatus (hereinafter also simply referred to as ink) having a polyhydric alcohol monoalkyl ether content of 10% by mass to 25% by mass with respect to the mass of the ink. The ink jet head is filled in advance before the ink jet recording apparatus ink is filled in the ink jet head. The ink used in the inkjet recording apparatus in which the preservation solution of the present invention is used is not particularly limited as long as the content of the polyhydric alcohol monoalkyl ether is 10% by mass or more and 25% by mass or less with respect to the mass of the ink. Various inks conventionally used in ink jet recording apparatuses can be used.

  The polyhydric alcohol monoalkyl ether contained in the ink is not particularly limited as long as it does not impair the object of the present invention, and can be appropriately selected from those conventionally used in inks for inkjet recording apparatuses. Specific examples of suitable polyhydric alcohol monoalkyl ethers include alkyl ethers of 1 to 6 carbon atoms of polyhydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol and propylene glycol.

[Inkjet head]
The ink jet head filled with the preservation solution of the present invention is not particularly limited, and may be a thermal method or a piezo method. Among the inkjet heads, a piezo inkjet head is more preferable because it is easy to control the amount of ink discharged. Here, the structure of the piezoelectric inkjet head 1 will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view of the inkjet head before the piezoelectric actuator is attached. FIG. 2 is an enlarged view showing a head structure per dot (one ink discharge port) in the ink jet head with the piezoelectric actuator attached.

  As shown in FIG. 1, in the inkjet head 1, a plurality of ejection units 12 that eject ink from one ejection port 13 are arranged in parallel to the ejection surface 11. A plurality of common channels 14 extending in parallel in the longitudinal direction of the inkjet head 1 are provided in the inkjet head 1, and each common channel 14 is connected to a pipe from an ink cartridge (not shown). For this purpose, an ink supply port 15 is provided.

  As shown in FIG. 2, the inkjet head 1 includes a pressurization chamber 16 provided for each discharge port 13, a nozzle 17 that continues from the pressurization chamber 16 to the discharge port 13, and the pressurization chamber 16. The piezoelectric element 18 and the individual electrode 19 provided above are provided. The pressurizing chamber 16 and the common channel 14 are communicated with each other through a supply hole 20. The preservation solution of the present invention is filled in the pressurizing chamber 16 or the pressurizing chamber 16 and the common flow path 14 before the ink jet head 1 is filled with ink. The ink jet head 1 filled with the preservative solution is provided with a cap at the discharge port 13 or a valve, a stopper, or the like at the ink introduction portion in order to eliminate air communication locations, thereby preventing the preservative solution from leaking or evaporating. May be.

  The pressurizing chamber 16 in the inkjet head 1 is filled with the storage solution by a pump (not shown) for supplying ink to the interior of the inkjet head 1. In addition, the storage liquid and the ink are replaced by supplying the pressurized ink to the pressurizing chamber 16 by a pump (not shown) for supplying the ink to the inside of the inkjet head 1, and discharging the ink by the pressure of the ink. 13 is carried out by extruding the stock solution. Since the preservation solution of the present invention is excellent in affinity with ink, the ink is satisfactorily filled without forming bubbles in the pressurizing chamber 16 after the preservation solution is discharged.

  The upper wall of the pressurizing chamber 16 is composed of a diaphragm 21 formed continuously over the plurality of pressurizing chambers 16. On the diaphragm 21, a common electrode 22 that is continuously formed over the plurality of pressurizing chambers 16 is similarly laminated. A separate piezoelectric element 18 is provided for each pressurizing chamber 16 on the common electrode 22, and an individual electrode 19 is separately provided for each pressurizing chamber 16 so as to sandwich the piezoelectric element 18 together with the common electrode 22. . A region other than the discharge port 13 on the discharge surface 11 is covered with a water-repellent film 11a to prevent ink adhesion.

  Each piezoelectric element 18 of the inkjet head 1 is individually driven by applying a driving pulse as a driving signal to an individual electrode 19 from a head driving unit (not shown) via a flexible cable (not shown). The By this drive, the piezoelectric element 18 is vibrated and deformed, and the deformation is transmitted to the diaphragm 21. The pressurizing chamber 16 is compressed by the deformation of the diaphragm 21. As a result, pressure is applied to the ink in the pressurizing chamber 16, and the ink that has passed through the nozzle 17 is ejected from the ejection port 13 as ink droplets onto the paper, and an image is recorded on the paper by the ink.

  The ink reduced by the discharge is changed from the ink cartridge (not shown) to the ink cartridge piping, the discharge port 13, the common flow path 14, and the pressure chamber 16 by the surface tension of the ink meniscus in the nozzle 17. 17 is filled.

  According to the preservation solution of the present invention, bubbles are unlikely to be generated when filling the inkjet head. Further, since the ink can be easily replaced in the ink jet head, a good image can be formed. Furthermore, the preservation solution of the present invention is not easily frozen even in a cold region, and the ink jet head is less likely to malfunction. For this reason, the inkjet head preservation | save liquid of this invention is used suitably in the image forming apparatus of a various inkjet recording system.

  Hereinafter, the present invention will be described more specifically with reference to examples. In addition, this invention is not limited at all by the Example.

[Reference Example 1]
<Preparation of ink for inkjet recording apparatus>
(Preparation of pigment dispersion)
Phthalocyanine blue was used as a pigment. 15% by mass pigment, 7% by mass styrene-acrylic acid copolymer resin (number average molecular weight: 50000, acid value 200), 0.5% by mass with respect to the total mass of materials used for preparing the pigment dispersion. % Surfactant (Orphine E1010, ethylene oxide adduct of acetylenic diol, manufactured by Nissin Chemical Industry Co., Ltd.), potassium hydroxide in an amount necessary for neutralization of styrene-acrylic acid copolymer resin, and residual amount Water was charged into a dyno mill (manufactured by Shinmaru Enterprises Co., Ltd.). Filling a dynomill with 1.5 times the mass of glass beads having a bead diameter of 0.5 mm as a medium to the total mass of materials used for preparing the pigment dispersion, the pigment and the styrene-acrylic acid copolymer resin Were kneaded to obtain a pigment dispersion. The obtained pigment dispersion was diluted 300 times with ion-exchanged water, and the volume average particle diameter D50 of the pigment was measured with a dynamic light scattering particle size distribution device (Zetasizer Nano, manufactured by Sysmex Corporation). It was confirmed that the volume average particle diameter of the pigment was in the range of 70 nm to 130 nm.

(Preparation of ink)
Ink 1 to Ink 5 were prepared by mixing the obtained pigment dispersion and the components shown in Table 1 at the ratios shown in Table 1. Specifically, the ink components were uniformly mixed with a stirrer and then filtered with a filter having a pore size of 5 μm to obtain inks 1 to 5.

[Example 1]
The components listed in Table 2 were uniformly mixed with a stirrer at the ratios listed in Table 2, and then filtered through a filter having a pore size of 5 μm to obtain an inkjet head preservation solution of Example 1.

(Evaluation of ink introduction)
For the ink-jet head preservation solution of Example 1, ink introduction properties were evaluated using inks 1 to 5 according to the following method. An inkjet head that applies force to ink with a piezo that vibrates flexibly, has 2656 nozzles that can be driven at a frequency of 1 to 40 kHz and a drive voltage of 10 to 30 V, and has a total volume of 6 cm ³ in the flow path in the head. The image forming apparatus provided was used. A cartridge filled with a storage solution was connected to the inkjet head, and the inkjet head was filled with the storage solution by purging twice for 1 second at a flow rate in the head of 6 cm ³ / second. After filling the inkjet head with the preservative solution, the ink-filled cartridge was connected to the inkjet head, and purge operation was performed 10 times at a flow rate of 2 cm ³ / sec for 1 second to introduce the ink into the inkjet head.

Following the ink purge operation, a nozzle check pattern was printed on glossy paper at a frequency of 20 kHz and a drive voltage of 20 V in order to confirm the replacement status of the storage liquid with ink, and nozzles that did not eject ink well (missing) The number of nozzles) was measured, and the ink filling rate, which is the ratio of the number of missing nozzles to the total number of nozzles, was calculated according to the following formula.
Ink filling rate = (total number of nozzles−number of missing nozzles) / total number of nozzles × 100
An ink filling rate of 100% was evaluated as ◯, less than 100% 90% or more was evaluated as Δ, and less than 90% was evaluated as ×. Table 4 shows the evaluation results of the ink introduction properties of the preservation solution of Example 1.

(Evaluation of freezing)
The ink jet head preservation solution of Example 1 was evaluated for freezing. Specifically, the storage solution was allowed to stand for 3 days in a thermostatic apparatus set at −20 ° C., and then the presence or absence of freezing of the storage solution was visually confirmed. Those that were not frozen were evaluated as ◯, and those that were frozen were evaluated as ×. The evaluation results of the freezing property of the preservation solution of Example 1 are shown in Table 4.

＊１：オルフィンＥ１０１０（アセチレンジオールのエチレンオキシド付加物、日信化学工業株式会社製）

* 1: Olfine E1010 (ethylene oxide adduct of acetylene diol, manufactured by Nissin Chemical Industry Co., Ltd.)

[Examples 2 to 4 and Comparative Examples 1 to 6]
A preservation solution was obtained in the same manner as in Example 1 except that the contents of the components contained in the preservation solution were changed to the contents shown in Tables 2 and 3. Using the preservation solutions obtained in Examples 2 to 4 and Comparative Examples 1 to 6, ink introduction properties and freezing were evaluated in the same manner as the preservation solution in Example 1. The evaluation of ink introduction properties and freezing properties of the storage solutions of Examples 2 to 4 is shown in Table 4, and the ink introduction properties and freezing properties of the storage solutions of Comparative Examples 1 to 6 are shown in Table 5.

＊１：オルフィンＥ１０１０（アセチレンジオールのエチレンオキシド付加物、日信化学工業株式会社製）

* 1: Olfine E1010 (ethylene oxide adduct of acetylene diol, manufactured by Nissin Chemical Industry Co., Ltd.)

＊１：オルフィンＥ１０１０（アセチレンジオールのエチレンオキシド付加物、日信化学工業株式会社製）

* 1: Olfine E1010 (ethylene oxide adduct of acetylene diol, manufactured by Nissin Chemical Industry Co., Ltd.)

  According to Table 4, according to the preservation solutions of Examples 1 to 4 containing 35% by mass or more and 70% by mass or less of polyhydric alcohol, 10% by mass or more and 25% by mass or less of polyhydric alcohol monoalkyl ether is included. It can be seen that inks 2 and 5 can be satisfactorily introduced into the ink jet head, and the storage solution does not freeze even at −20 ° C.

  In addition, according to Table 4, even when the preservation solutions of Examples 1 to 4 are used, the ink 1, the ink 3, and the content of the polyhydric alcohol monoalkyl ether is less than 10% by mass or more than 25% by mass, and It can be seen that when ink 4 is used, good ink introduction properties cannot be obtained. From this, the preservation solution of the present invention of Examples 1 to 4 is a particularly suitable preservation solution in an ink jet recording apparatus using an ink having a polyhydric alcohol monoalkyl ether content of 10% by mass or more and less than 25% by mass. I understand that there is.

  On the other hand, according to Table 5, in the preservation solution of Comparative Examples 1 to 6 in which the polyhydric alcohol content is less than 35% by mass or more than 70% by mass, the preservation solution is replaced with ink without causing a missing nozzle. In both cases, it can be seen that the preservation solution is frozen.

DESCRIPTION OF SYMBOLS 1 Inkjet head 11 Ejection surface 11a Water repellent film 12 Ejection unit 13 Ejection port 14 Common flow path 15 Ink supply port 16 Pressurizing chamber 17 Nozzle 18 Piezoelectric element 19 Individual electrode 20 Supply hole 21 Diaphragm 22 Common electrode

Claims (4)

In an ink jet recording apparatus using an ink for an ink jet recording apparatus, wherein the content of the polyhydric alcohol monoalkyl ether is 10% by mass or more and 25% by mass or less with respect to the mass of the ink and includes 1,3-butanediol. An ink filling method for filling the ink for an ink jet recording apparatus,
The inkjet head is pre-filled with an inkjet storage solution,
Filling the ink jet head filled with the ink jet head preservation liquid with the ink for the ink jet recording apparatus,
The inkjet head preservation solution contains at least water, a surfactant, a dissolution stabilizer, and a polyhydric alcohol,
The polyhydric alcohol is a mixture of propylene glycol and glycerin, or propylene glycol;
The ink filling method, wherein a content of the polyhydric alcohol is 35% by mass or more and 70% by mass or less with respect to a mass of the ink jet head preservation solution.   The ink filling method according to claim 1, wherein a content of the surfactant is 1% by mass or more and 3% by mass or less with respect to a mass of the ink jet head preservation solution.   The ink filling method according to claim 1, wherein a content of glycerin in the mixture of propylene glycol and glycerin is 20% by mass or more and 90% by mass or less. The ink filling method according to claim 1, wherein the ink-jet head preservation solution does not freeze at −20 ° C.

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