JP2012016824A - Liquid ejector and method of stirring degassing liquid used for use therein - Google Patents

Abstract

An object of the present invention is to provide an ink-derived adhesive (cake) that is excellent in printing stability, hardly causes printing defects, and is derived from ink.
A liquid discharge apparatus such as an ink jet recording apparatus capable of eliminating the accumulation of the liquid and a method of stirring and degassing the liquid used in the liquid discharge apparatus.
A printer head that discharges liquid from a nozzle toward a target medium, a target medium transport unit that transports the target medium to a position facing the printer head, and the liquid that is supplied to the printer head A supply path that communicates with the supply path, stores the liquid, an ultrasonic deaeration mechanism that ultrasonically degasses the liquid in the reservoir, and agitates the liquid in the reservoir A liquid ejection device having a stirring mechanism.
[Selection] Figure 1

Description

  The present invention relates to a liquid discharge apparatus and a liquid stirring and degassing method used for the same.

2. Description of the Related Art Conventionally, as one of liquid ejecting apparatuses, an ink jet printer that performs printing by ejecting a liquid such as ink onto various ejected media such as paper, cloth, and film is known. Ink jet printers are inexpensive, and liquid can be used efficiently and running cost is low because liquid is ejected only on the required image area and image formation is performed directly on the medium to be ejected. Furthermore, since an inkjet printer has low noise, it is excellent as an image forming method.

However, when bubbles or dissolved gas is present in the liquid used in the ink jet printer, the liquid is not sufficiently compressed at the time of discharge, and thus the discharge performance is lowered and stable liquid particles cannot be generated. That is, in such a case, the printing stability is inferior. In addition, there is a problem that dot dropout or printing failure occurs, and the reliability of inkjet printing is lowered. Therefore, attempts have been made to prevent bubbles and dissolved gases from being present in the liquid used.

For example, Patent Document 1 discloses a method for degassing ink by allowing ink for inkjet recording after heating to pass through a gas-permeable film. Patent Document 2 discloses an ink jet recording apparatus having a vacuum deaeration mechanism in which the degree of deaeration vacuum is adjusted to a predetermined range. Further, Patent Document 3 discloses an ink jet recording apparatus in which an ultrasonic vibration source for degassing a gas contained in ink is attached to a lower portion of a side wall surface of a reserve tank connected to a print head. .

JP 2003-253169 A JP 2008-87273 A JP 2000-301733 A

However, in the ink degassing method disclosed in Patent Document 1 and the ink jet recording apparatus disclosed in Patent Document 2 and Patent Document 3, printing stability, printing defects, and particularly white ink are still remarkable. There is a practical problem in terms of the accumulation of the ink-derived adhesive (cake) that can be seen.

Therefore, the present invention provides a liquid ejection apparatus such as an ink jet recording apparatus, which has excellent printing stability, is unlikely to cause defective printing, and can eliminate the deposition of an ink-derived adhesive (cake), and agitation of liquid used in the apparatus. One of the purposes is to provide a degassing method.

In order to solve the above problems, the inventor of the present application has intensively studied an ink deaeration unit in an ink jet recording apparatus which is an example of a liquid ejecting apparatus.

Inks include pigment-based inks and dye-based inks depending on the color material used. Pigment-based inks are suitable as display inks because they are superior in storage stability of recorded matter compared to dye-based inks. However, there is a problem peculiar to pigment-based inks, namely precipitation of pigment particles. In particular, when the pigment-based ink is a white ink, titanium oxide is often used to maintain whiteness. However, because titanium oxide has a large specific gravity, sedimentation is noticeable (the sedimentation rate is very large). As a countermeasure for preventing such sedimentation, the recording apparatus is provided with a stirring mechanism.

On the other hand, air bubbles are not preferable in the inkjet ink from the viewpoint of ejection reliability. When the ink jet recording apparatus was equipped with a stirring mechanism, it was found that bubbles in the ink were involved during recording, and as a result, the ejection reliability of the ink jet ink was adversely affected.

Therefore, as a result of further investigation by the present inventor, sedimentation of the pigment is eliminated and the ejection reliability is excellent by the liquid ejection device that includes both the stirring mechanism and the ultrasonic deaeration mechanism, that is, the ink jet recording apparatus. As a result, the present invention has been completed.

Furthermore, solvent-based inks with high viscosity, such as UV curable inks, require a long time for deaeration of the ink in a normal stationary state, but the present invention performs stirring together with deaeration of the ink. As a result, it was revealed that the deaeration performance can be improved and the deaeration time can be shortened.

That is, the present invention is as follows.
[1]
A printer head that discharges liquid from a nozzle toward the discharge medium; a discharge medium transfer unit that transfers the discharge medium to a position facing the printer head; and a supply path that supplies the liquid to the printer head. A reservoir that communicates with the supply path and stores the liquid, an ultrasonic deaeration mechanism that ultrasonically degass the liquid in the reservoir, and an agitation mechanism that agitates the liquid in the reservoir A liquid ejecting apparatus.
[2]
The liquid ejection apparatus according to [1], wherein the liquid is a liquid composition containing a metal oxide.
[3]
The liquid ejecting apparatus according to [1] or [2], wherein the printer head is provided in a carriage and the reservoir is provided in the carriage.
[4]
The liquid ejecting apparatus according to [1] or [2], wherein the printer head is provided in a carriage, and the reservoir is provided in a place other than the carriage.
[5]
The liquid ejecting apparatus according to any one of [1] to [4], wherein the reservoir is a liquid cartridge.
[6]
The liquid ejection device according to any one of [1] to [5], further including a transport pump provided in the supply path.
[7]
A liquid agitation and deaeration method for use in a liquid ejection apparatus, comprising ultrasonically deaeration while stirring the liquid used in the liquid ejection apparatus according to any one of [1] to [6].

It is a schematic block diagram which shows an example of the inkjet recording device of this invention. It is a schematic block diagram which shows an example of the inkjet recording device of this invention. It is a schematic block diagram which shows an example of the inkjet recording device of this invention. It is a schematic block diagram which shows an example of the inkjet recording device of this invention. It is a flowchart which shows an example of the recording operation | movement of the inkjet recording device used by this invention. It is a flowchart which shows an example of the recording operation | movement of the inkjet recording device used by this invention. It is a flowchart which shows an example of the recording operation | movement of the inkjet recording device used by this invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail. In addition, this invention is not restrict | limited to the following embodiment, A various deformation | transformation can be implemented within the range of the summary.

In the present specification, as described above, the “liquid ejecting apparatus” performs printing by ejecting liquid such as ink onto various ejected media such as paper, cloth, and film, and includes an ink jet printer. . As described above, this ink jet printer ejects liquid only to a required image portion and directly forms an image on a medium to be ejected. The “recording apparatus” included in the liquid ejecting apparatus is an image recording apparatus for forming an image on a recording medium such as paper based on an image data signal, and includes an ink jet recording apparatus. This inkjet recording apparatus
Ink is ejected only to the required image area to form an image directly on the recording medium. Accordingly, the ink jet recording apparatus is included as an example of a liquid ejection apparatus.

Further, in the present specification, “ultrasonic deaeration” means that by applying ultrasonic waves to the ink, the bubbles taken into the pigment or the like are separated, and the separated bubbles are united. It means to rise to the liquid level and deaerate. Further, unless otherwise specified in the present specification, “stirring” means stirring by only the stirring mechanism, not the ultrasonic mechanism. Furthermore, "ultrasonic stirring"
It means that an ultrasonic mechanism and a stirring mechanism are used.

Further, the on-carriage method and the off-carriage method in this specification are, for example, edited by the Japanese Imaging Society, “Series“ Digital Printer Technology ”Inkjet”, Tokyo Denki University Press, September 10, 2008, first edition, p. 190, 191. here,"
The “on-carriage method” means an ink supply method in which an ink cartridge is mounted on a carriage together with a print head. The “off-carriage method” means an ink supply method in which an ink cartridge is not mounted on a carriage but is installed in another place and connected to a print head on the carriage by a tube or the like. The “sub ink tank” is an ink tank that is installed between the print head and the ink cartridge when a tube is connected from the ink cartridge to the print head on the carriage by an off-carriage method. Further, the “sub ink tank” refers to a relay tank installed above the printer head in order to increase the degree of freedom of installation of the main ink tank (ink cartridge), for example, it can be below the print head. .

The ink jet recording apparatus and ink jet recording ink stirring and degassing method of the present embodiment will be described below with reference to the drawings. In addition, in FIG.
Assume that the positional relationship is as shown in the figure.

[First Embodiment]
[Inkjet recording device configuration]
One embodiment of the present invention relates to a liquid ejection apparatus. The liquid ejection apparatus includes: a printer head that ejects liquid from a nozzle toward the ejection medium; a ejection medium conveyance unit that conveys the ejection medium to a position facing the printer head; and the liquid on the printer head. A supply path for supplying the liquid, a reservoir connected to the supply path for storing the liquid, an ultrasonic deaeration mechanism for ultrasonically degassing the liquid in the reservoir, and the liquid in the reservoir And a stirring mechanism for stirring.
An ink jet recording apparatus which is an example embodying the liquid ejecting apparatus is a printer head that ejects ink (corresponding to liquid in the liquid ejecting apparatus) from a nozzle toward a recording medium (corresponding to the ejected medium in the liquid ejecting apparatus). A recording medium conveying means for conveying the recording medium to a position facing the printer head (equivalent to an ejection medium conveying means in a liquid ejection apparatus), a supply path for supplying the ink to the printer head, A reservoir that communicates with the supply path and stores the ink; an ultrasonic deaeration mechanism that ultrasonically degasses the ink in the reservoir; and an agitation mechanism that agitates the ink in the reservoir; Have

FIG. 1 is a schematic configuration diagram illustrating an example of an ink jet recording apparatus according to the present embodiment. The recording apparatus 1 is supplied with a reservoir 2, a stirring mechanism 4, an ultrasonic deaeration mechanism 5, a supply path 6, a check valve 7, and a printer head 8. The reservoir 2 stores the ink 3 for deaeration. The stirring mechanism 4 is for stirring the ink 3 stored in the reservoir 2. The ultrasonic degassing mechanism 5 is for ultrasonically degassing the ink 3 stored in the reservoir 2.
The ultrasonic deaeration mechanism 5 is, for example, an ultrasonic generator. The supply path 6 is for feeding the ink 3. The supply path 6 communicates with the reservoir 2. The supply path 6 may include a liquid feed pump in the middle thereof. The check valve 7 prevents backflow of the ink 3 supplied (liquid feeding) to an arbitrary position in the supply path 6. The printer head 8 is a destination to which the ink 3 is supplied (liquid feeding) through the supply path 6. The printer head 8 ejects the ink 3 from the nozzle toward the recording medium.

Here, it is preferable that the printer head 8 is provided in the carriage and the reservoir 2 is provided in the carriage. Specifically, the reservoir 2 provided with the stirring mechanism 4 and the ultrasonic deaeration mechanism 5 is preferably an on-carriage ink cartridge. In this case, since the ink can be supplied using the water head value, a pump is not necessary.

Alternatively, it is also preferable that the printer head 8 is provided in a carriage and the reservoir 2 is provided in a place other than the carriage. More specifically, the reservoir 2 may be replaced with at least one of an off-carriage ink cartridge and an ink tank communicating with the off-carriage ink cartridge and the printer head. In this case, the printer head can be reduced in size. In this modification, the mechanisms 4 and 5 are provided in the sub ink tank. FIG. 3 to be described later shows a modification including such a sub ink tank.

The printer head 8 includes a nozzle (not shown) for discharging and landing (attaching) the ink 3 toward the recording medium. A recording medium conveying means (not shown) of the present invention for conveying the recording medium is provided at a position facing the printer head 8.

When the ink 3 is an ultraviolet curable ink, a light irradiation means (ultraviolet irradiation lamp) (not shown) is provided downstream from the position facing the printer head 8 in the transport portion of the recording medium.

[Inkjet recording method (operation)]
FIG. 5 is a flowchart showing an example of an ink jet recording method using the ink jet recording apparatus of the present embodiment. The recording method will be briefly described. First, after receiving a printing command (S10), an ultrasonic stirring operation is performed (S11). After stirring, printing is performed (S12).
In this way, during the printer stop time, the ultrasonic stirring operation is performed before starting printing in consideration of the sedimentation of ink components or the mixing of bubbles.

Specifically, the ink jet recording method is characterized in that it includes at least a stirring deaeration step and a discharge step. Further, when the ink to be used is an ultraviolet curable ink, the recording method may include a curing step. Hereafter, each process is demonstrated in detail according to the step of a flowchart.

(Print command (S10))
The print command instructs image data to be printed and printing. Image data is transmitted from a computer apparatus (not shown) to the ink jet recording apparatus together with a print command.

(Ultrasonic stirring operation (S11))
The ultrasonic stirring operation corresponds to the stirring deaeration step of the present invention. For example, (1) driving of the ultrasonic deaeration mechanism 5 that is an ultrasonic deaeration device (starting ultrasonic irradiation), (2) starting stirring, (3) stopping stirring,
The process proceeds in the order of (4) printing, and (5) stop of the ultrasonic deaeration mechanism 5 (stop of ultrasonic irradiation).

When the ultrasonic wave of (1) is first applied, the precipitate is easily eliminated by the subsequent stirring of (2). By stirring, ultrasonic degassing can be effectively achieved even in the case of ink having a high viscosity. If the stirring is continued, bubbles are taken into the ink 3. Therefore, stirring is stopped while applying ultrasonic waves (above (3)), and ultrasonic deaeration is performed for a while, so that the bubbles are taken into the ink 3 by stirring. Eliminate air bubbles. After printing (4) above, the ultrasonic wave is stopped (above (5)).

According to this embodiment, the ink 3 that has taken in bubbles as a result of the settling agitation can be degassed by ultrasonic degassing. In addition, this embodiment is particularly effective for white ink in which a cake (aggregated thickened product) is generated. If you try to dissolve the cake by stirring, you can increase the rotation speed of stirring,
The stirring time is lengthened, and as a result, the bubbles are easily taken into the ink 3. Therefore, it is difficult to eliminate the cake only by stirring using the stirring mechanism 4.
Therefore, when ultrasonic waves are applied using the ultrasonic deaeration mechanism 5 in addition to the stirring mechanism 4, this cake can be eliminated in a very short time, and as a result, bubbles are less likely to be taken into the ink 3. .

(Print (S12))
In printing, (4) printing is performed. Specifically, at least the ejection step (4-1) is performed, and when the ink to be used is an ultraviolet curable ink, the curing step (4-2) is performed. Note that printing may be started while applying ultrasonic waves. That is, printing may be performed after any operation as long as it is after the operation (3), or may be performed after the operation (5).

(Discharge process (4-1))
The ejection process in the present embodiment is a process for landing the ink 3 after the stirring and deaeration process on the recording medium by ejecting the ink 3 from the printer head 8. As described above, the recording medium transport unit transports the recording medium to a position facing the printer head 8. The printer head 8 ejects the ink 3 onto a recording medium and causes it to land. For example, cyan,
When magenta, yellow, and black inks are required, ink 3 is prepared for each color. The printer head 8 may be a headset in which a plurality of heads for ejecting the ink 3 of each color are arranged along the conveyance direction of the recording medium. Also, the printer head 8
May be provided with a plurality of nozzles for ejecting ink 3 of each color in a direction orthogonal to the conveyance direction of the recording medium.

As described above, a conventionally known method can be used as an ink jet recording method for forming an image by ejecting and landing the ink 3 on a recording medium. Among these, excellent quality can be obtained by using a method of ejecting droplets using vibration of a piezoelectric element, that is, a recording method using an ink jet head that forms ink dots by mechanical deformation of an electrostrictive element. An image can be formed.

(Curing process (4-2))
The curing step in the present embodiment is a step in which the ink 3 is cured by irradiating light in a specific wavelength region after the ejection step.

As described above, when the ink 3 is an ultraviolet curable ink, a light irradiation means (ultraviolet irradiation lamp) (not shown) is provided. Therefore, the light in the specific wavelength region is preferably an ultraviolet (UV) ray region. The ultraviolet irradiation lamp irradiates the ink (ultraviolet curable ink) 3 landed on the recording medium with ultraviolet rays to cure the ink 3. The specific wavelength range (ultraviolet range) is, for example, in the range of 360 to 450 nm, preferably in the range of 360 to 410 nm, and more preferably in the range of 380 to 400 nm. Cost is low. In addition, when the wavelength range of the ink in the embodiment of the present invention is within the above range, the curability is further improved.

The amount of light irradiation is preferably 10 to 20,000 mJ / cm ² , more preferably 5
0 to 15,000 mJ / cm ² . When the irradiation amount is within the above range, the curing reaction can be sufficiently performed.

Examples of the light emission source (light irradiation means) in the above wavelength range include a mercury lamp and a metal halide lamp. On the other hand, from the viewpoint of environmental protection, since mercury-free is strongly desired, replacement of GaN-based semiconductors with ultraviolet light-emitting devices is progressing. Light emitting diodes (LEDs) and laser diodes (LDs) are being used as light sources for photo-curing inkjet recording because of their small size, high efficiency, and long life. Among these, a light emitting diode (LED) having a peak wavelength in the range of 360 to 400 nm is preferable from the viewpoint of cost and versatility.

As described above, according to the present embodiment, an ink jet recording apparatus that has excellent printing stability, is unlikely to cause printing defects, and can eliminate the accumulation of ink-derived adhesive (cake) can be obtained.
More specifically, by combining stirring and ultrasonic waves, sedimentation can be recovered while maintaining printing stability. In particular, when the stirring mechanism is used alone, the printing stability is adversely affected. However, when combined with the ultrasonic mechanism, the printing stability is better than that when the ultrasonic mechanism is used alone. Show the characteristics. In addition, by applying ultrasonic waves, separation of pigments aggregated due to sedimentation can be quickly achieved.

[Second Embodiment]
The second embodiment differs from the first embodiment in that it is determined whether or not the ultrasonic stirring operation is further performed after determining whether or not a predetermined time has elapsed since the previous ultrasonic stirring operation.
[Liquid ejection device configuration]
Since the apparatus configuration is the same as that described with reference to FIG. 1, the description thereof is omitted here.

[Inkjet recording method (operation)]
FIG. 6 is a flowchart showing a modification of the ink jet recording method using the ink jet recording apparatus used in the present embodiment. According to this recording method, first, after receiving a print command (S20), it is determined whether or not a predetermined time has elapsed since the previous ultrasonic stirring operation (S21).
). When a predetermined time has elapsed since the previous ultrasonic stirring operation (S21: Y), ultrasonic stirring is performed (S22). Thereafter, printing is performed (S23). On the other hand, when the predetermined time has not elapsed since the previous ultrasonic stirring operation (S21: N), printing is performed without performing ultrasonic stirring (
S23).

The cause of the necessity of ultrasonic agitation includes sedimentation of ink components or mixing of bubbles. Therefore, the time when any of these can occur is set to a predetermined time (several hours, one day, several days, etc.).

Here, the above-mentioned sedimentation refers to sedimentation of pigment components and the like, and the sediment becomes cake after a long time. The generation of the bubbles is caused by oxygen or the like dissolved in the ink being gasified to generate bubbles, or gas being mixed into the ink container through the wall of the ink container.
The contents of the print command (S20), the ultrasonic stirring operation (S22), and the printing (S23) are respectively the print command (S10), the ultrasonic stirring operation (S11), and the printing (described in the first embodiment). Since it overlaps with each content of S12), description here is abbreviate | omitted.

As described above, according to the present embodiment, an ink jet recording apparatus that has excellent printing stability, is unlikely to cause printing defects, and can eliminate the accumulation of ink-derived adhesive (cake) can be obtained.
More specifically, by combining stirring and ultrasonic waves, sedimentation can be recovered while maintaining printing stability. In particular, when the stirring mechanism is used alone, the printing stability is adversely affected. However, when combined with the ultrasonic mechanism, the printing stability is better than that when the ultrasonic mechanism is used alone. Show the characteristics. In addition, by applying ultrasonic waves, separation of pigments aggregated due to sedimentation can be quickly achieved. Furthermore, this embodiment differs from the first embodiment described above in order to determine whether or not the ultrasonic stirring operation is further performed after determining whether or not a predetermined time has elapsed since the previous ultrasonic stirring operation. The sonic stirring operation can be suitably controlled.

[Third Embodiment]
In the third embodiment, two stages of predetermined time are prepared according to the effect of ultrasonic stirring, and after determining whether or not the predetermined time has passed since the previous ultrasonic stirring operation, the ultrasonic stirring operation, that is, The second embodiment is different from the second embodiment in that it is determined whether the ultrasonic operation and the stirring operation are performed or only the ultrasonic operation is performed.
[Liquid ejection device configuration]
Since it is the same as that described in FIG. 1, the description thereof is omitted here.

[Inkjet recording method (operation)]
FIG. 7 is a flowchart showing a modification of the ink jet recording method using the ink jet recording apparatus used in this embodiment. Here, first, after receiving a print command (S30
), It is determined whether the first predetermined time or more has elapsed since the previous ultrasonic stirring operation (S31).
). When the first predetermined time or more has elapsed since the previous ultrasonic stirring operation (S31: Y), the ultrasonic stirring operation is performed in order to eliminate ink sedimentation, particularly cake formation, due to a long time (S31).
32). Thereafter, printing is performed (S33). If the first predetermined time or more has not elapsed since the previous ultrasonic stirring operation (S31: N), and if the second predetermined time has elapsed since the previous ultrasonic stirring operation (S34: Y), the ink Even if the ink settles, it is determined that the cake does not reach agitation requiring stirring, or that there is no ink sedimentation and only bubbles are mixed, and only the ultrasonic operation is performed (S35). Thereafter, printing is performed (S33). When the first predetermined time or more has not elapsed since the previous ultrasonic stirring operation (S31: N), and when the second predetermined time has not elapsed since the previous ultrasonic stirring operation (S34: N), Printing is performed without performing the sonic stirring operation and the ultrasonic operation (S33).

Here, the first predetermined time is a time during which sedimentation of the ink component can occur, and the second predetermined time is a time during which either an increase in dissolved gas amount or mixing of bubbles can occur.

The contents of the printing command (S30), the ultrasonic stirring operation (S32), and the printing (S33) are respectively the printing command (S10), the ultrasonic stirring operation (S11), and the printing (described in the first embodiment). Since it overlaps with each content of S12), description here is abbreviate | omitted. On the other hand, the ultrasonic operation (S35) is different from the ultrasonic stirring operation (S11) and corresponds to an operation in which stirring is not performed in the ultrasonic stirring operation (S11) described in the first embodiment.

As described above, according to the present embodiment, an ink jet recording apparatus that has excellent printing stability, is unlikely to cause printing defects, and can eliminate the accumulation of ink-derived adhesive (cake) can be obtained.
More specifically, by combining stirring and ultrasonic waves, sedimentation can be recovered while maintaining printing stability. In particular, when the stirring mechanism is used alone, the printing stability is adversely affected. However, when combined with the ultrasonic mechanism, the printing stability is better than that when the ultrasonic mechanism is used alone. Show the characteristics. In addition, by applying ultrasonic waves, separation of pigments aggregated due to sedimentation can be quickly achieved.

Furthermore, this embodiment is different from the second embodiment described above in accordance with the effect of ultrasonic stirring.
Prepare a predetermined time for each stage and determine whether a predetermined time has passed since the previous ultrasonic stirring operation, and then perform ultrasonic stirring operation, that is, ultrasonic operation and stirring operation, or ultrasonic operation Therefore, the ultrasonic stirring operation can be controlled more suitably, and unnecessary operations can be omitted, so that the time until the start of printing can be shortened.

[Fourth Embodiment]
In the fourth embodiment, a sub ink tank 2b having an ultrasonic deaeration mechanism 5b is provided, and the provision of a transport pump 9 in the supply path 6 increases the degree of freedom in the position of the main ink tank 2a. This is different from the first embodiment.
[Liquid ejection device configuration]
FIG. 2 is a schematic diagram illustrating a modified example of the ink jet recording apparatus which is an example of the liquid ejection apparatus according to the present embodiment. Unlike the recording apparatus 1 shown in FIG. 1, the recording apparatus 21 in this modification is further provided with a reservoir 2 b, an ultrasonic deaeration mechanism 5 b, and a transport pump 9. The transport pump 9 is provided in the middle of the supply path 6. Check valves 7 are provided on both sides of the supply path 6 with the transport pump 9 interposed therebetween.

The reservoir 2a is provided with a stirring mechanism 4a and an ultrasonic deaeration mechanism 5a.
The reservoir 2a is, for example, an ultrasonic generator. The reservoir 2b is provided with an ultrasonic deaeration mechanism 5b. The ultrasonic deaeration mechanism 5b is, for example, an ultrasonic generator. The reservoir 2b is provided closer to the printer head 8 than the transport pump 9 in the supply path 6. Reservoir 2a
Is a main ink tank, while the reservoir 2b is a sub ink tank.

[Inkjet recording method (operation)]
FIG. 5 is a flowchart showing an example of an ink jet recording method using the ink jet recording apparatus of the present embodiment. Since this flowchart has already been described in the first embodiment, a description common to both embodiments is omitted here. Hereinafter, this embodiment will be described in detail.

(Print command (S10))
The print command instructs image data to be printed and printing. Image data is transmitted from a computer apparatus (not shown) to the ink jet recording apparatus together with a print command.

(Ultrasonic stirring operation (S11))
In general, the ultrasonic stirring operation is as follows: (1) driving of the ultrasonic degassing mechanism 5a (starting of ultrasonic irradiation), (2) starting of stirring, (3) stopping of stirring, and (4) in the sub ink tank 2b. Ink supply, (
5) The ultrasonic degassing mechanism 5b is driven (ultrasonic irradiation start), (6) printing, and (7) the ultrasonic degassing mechanisms 5a and 5b are stopped (ultrasonic irradiation stop) in this order. Note that printing may be performed after the operation (7). (6) Printing will be described later.

After the ultrasonic degassing of (1) above, when the stirring of (2) above is started, sedimentation can be efficiently eliminated. After the stirring in (3) is stopped, ultrasonic deaeration is continued, and the sub ink tank 2b
Ink 3 is supplied using a transport pump 9 ((4) above). After supplying the deaerated ink 3 to the sub ink tank 2b, the ultrasonic deaeration of the main ink tank 2a which is an ink cartridge may be stopped. Further, as described in (5) above, by providing the ultrasonic degassing mechanism 5b in the sub ink tank 2b, settling in the sub ink tank 2b can be suppressed, and a slight degassing is also possible. After performing the printing of (6) above, the ultrasonic deaeration mechanisms 5a and 5b are stopped (above (7)). Note that printing may be started while applying ultrasonic waves. The printing may be performed after any operation as long as it is after the operation (5).

By providing the sub ink tank 2b and supplying the ink 3 to the sub ink tank 2b by the transport pump 9, the main ink tank 2a can be considered without considering the water head difference.
Need not be disposed above the printer head 8. Therefore, the degree of freedom of the position where the main ink tank 2a is provided increases.

(Print (S12))
In printing, (6) printing is performed. Specifically, at least the ejection step (6-1) is performed, and when the ink to be used is an ultraviolet curable ink, the curing step (6-2) is performed. Printing may be performed after the operation (7).
In addition, since the discharge process and hardening process in this embodiment are the same as that of the said 1st Embodiment, description is abbreviate | omitted here.

  In the flowchart of FIG. 6, an ultrasonic stirring operation is always performed before printing.

In the flowchart of FIG. 7, the ultrasonic stirring operation is performed before printing only when a predetermined time has elapsed since the previous ultrasonic stirring operation.
This embodiment is different from the first embodiment in that a process of supplying ink to the sub ink tank 2b with a pump after ultrasonic stirring is added. The ultrasonic deaeration mechanism 5b may start driving after a printing command, but may be stopped from the viewpoint of power saving. When stirring is not required, that is, when a certain time has not elapsed since the previous ultrasonic stirring, the ultrasonic stirring operation of the main ink tank 2a is not necessary, and only the ultrasonic operation of the ultrasonic deaeration mechanism 5b is performed. Good.

As described above, according to the present embodiment, an ink jet recording apparatus that has excellent printing stability, is unlikely to cause printing defects, and can eliminate the accumulation of ink-derived adhesive (cake) can be obtained.
More specifically, by combining stirring and ultrasonic waves, sedimentation can be recovered while maintaining printing stability. In particular, when the stirring mechanism is used alone, the printing stability is adversely affected. However, when combined with the ultrasonic mechanism, the printing stability is better than that when the ultrasonic mechanism is used alone. Show the characteristics. In addition, by applying ultrasonic waves, separation of pigments aggregated due to sedimentation can be quickly achieved. Furthermore, unlike the first embodiment, the present embodiment can suppress sedimentation in the sub ink tank 2b by providing the sub ink tank 2b having the ultrasonic deaeration mechanism 5b, and can also slightly deaerate. It becomes. Furthermore, in the present embodiment, unlike the first embodiment described above, the degree of freedom of the position of the main ink tank 2a is increased by providing the transport pump 9 in the supply path 6.

[Fifth Embodiment]
In the fifth embodiment, by providing the sub ink tank 2d having the ultrasonic deaeration mechanism 5d, settling in the sub ink tank 2d can be suppressed, and a slight deaeration is possible, and bubbles are formed in the ink 3. It differs from the first embodiment in that it is difficult to be taken in and that the degree of freedom in the position of the main ink tank 2c is increased by providing the transport pump 9 in the supply path 6.
[Liquid ejection device configuration]
FIG. 3 is a schematic diagram illustrating a modified example of the ink jet recording apparatus which is an example of the liquid ejection apparatus according to the present embodiment. Unlike the recording apparatus 1 shown in FIG. 1, the recording apparatus 31 in this modification is further provided with a reservoir 2d, a stirring mechanism 4d, an ultrasonic deaeration mechanism 5d, and a transport pump 9. The reservoir 2c is a reservoir 2 in the recording apparatus 1 shown in FIG.
Corresponding to The reservoir 2c includes a stirring mechanism 4c and an ultrasonic deaeration mechanism 5c. The ultrasonic deaeration mechanism 5c is, for example, an ultrasonic generator. The reservoir 2d includes a stirring mechanism 4d and an ultrasonic deaeration mechanism 5d. The ultrasonic degassing mechanism 5d is, for example, an ultrasonic generator. The reservoir 2d is provided closer to the printer head 8 than the transport pump 9 in the supply path 6. Reservoir 2c
Is a main ink tank, while the reservoir 2d is a sub ink tank.

The reservoir 2d is provided in the recording device 31. When the ink in the reservoir 2d runs out or becomes low, the ink 3 may be replenished to the reservoir 2d. Alternatively, the reservoir 2d may be a detachable cartridge type as shown in FIG. 4 to be described later, that is, an ink cartridge provided in the recording device 31, instead of the sub ink tank shown in FIG. Good. In this case, when the ink 3 runs out or decreases, the ink cartridge may be replaced.

[Inkjet recording method (operation)]
FIG. 5 is a flowchart showing an example of an ink jet recording method using the ink jet recording apparatus of the present embodiment. Since this flowchart has already been described in the first embodiment, the description of the contents common to these embodiments is omitted here. Less than,
This embodiment will be described in detail.

(Print command (S10))
The print command instructs image data to be printed and printing. Image data is transmitted from a computer apparatus (not shown) to the ink jet recording apparatus together with a print command.

(Ultrasonic stirring operation (S11))
The ultrasonic stirring operation includes (1) driving the ultrasonic deaeration mechanism 5c of the main ink tank 2c (starting ultrasonic irradiation), (2) starting stirring of the main ink tank 2c, and (3) main ink tank 2
c) Stop stirring, (4) Drive the ultrasonic degassing mechanism 5d of the sub ink tank 2d (start ultrasonic irradiation), (5) Start stirring of the sub ink tank 2d, (6) Stop stirring of the sub ink tank 2d, The process proceeds in the order of (7) printing and (8) stop of the ultrasonic deaeration mechanisms 5c and 5d (stop of ultrasonic irradiation). Note that printing may be performed after any operation as long as it is after the operation (6).

After the ultrasonic degassing of (1) above, when the stirring of (2) above is started, sedimentation can be efficiently eliminated. After the stirring in (3) above is stopped, ultrasonic deaeration is continued, and the sub ink tank 2d
Ink 3 is supplied using a transport pump 9. After supplying the deaerated ink 3 to the sub ink tank 2d, the ultrasonic deaeration of the main ink tank 2c, which is an ink cartridge, may be stopped. Further, as in the above (4) and (5), the sub-ink tank 2d has the stirring mechanism 4
By providing d and the ultrasonic deaeration mechanism 5d, both the subsidence and deaeration in the sub ink tank 2d can be efficiently performed. After stopping the stirring in (6) above, the printing in (7) is performed,
Thereafter, the ultrasonic irradiation is stopped ((8) above). Note that printing may be started while applying ultrasonic waves.

According to this embodiment, not only the main ink tank 2c but also the sub ink tank 2d is provided with the stirring mechanism 4d, which is extremely excellent in eliminating cake. For this reason, this embodiment is particularly effective for white ink in which a cake (aggregated thickened product) is generated. Further, by providing the stirring mechanism 4d and the ultrasonic deaeration mechanism 5d in the sub ink tank 2d, the cake can be eliminated in a very short time, and as a result, bubbles are not easily taken into the ink 3. Also,
Since the sub-ink tank 2d is also provided with the stirring mechanism 4d, it can be restored even when it is made into a cake. For example, maintenance that requires refreshing the ink before making the cake is not necessary, and the user uses ink. The amount can be reduced.

Further, a sub ink tank 2d is provided, and the sub ink tank 2 is provided by the transport pump 9.
By supplying the ink 3 to d, the main ink tank 2c is connected to the printer head 8
Therefore, the degree of freedom of the position of the main ink tank 2c is increased.

(Print (S12))
In printing, (7) printing is performed. Specifically, at least the ejection step (7-1) is performed, and when the ink to be used is an ultraviolet curable ink, the curing step (7-2) is performed. The printing may be performed after any operation as long as it is after the operation (6).
In addition, since the discharge process and hardening process in this embodiment are the same as that of the said 1st Embodiment, description is abbreviate | omitted here.

  In the flowchart of FIG. 6, an ultrasonic stirring operation is always performed before printing.

In the flowchart of FIG. 7, the ultrasonic stirring operation is performed before printing only when a predetermined time has elapsed since the previous ultrasonic stirring operation.
In the present embodiment, unlike the first to fourth embodiments, the sub-ink tank 2b is also provided with the stirring mechanism 4d, so that the cake in the sub-ink tank 2b can be recovered.
Therefore, in the case as shown in FIG. 2, it is necessary to prevent the ultrasonic wave from occurring before the cake that cannot be recovered only by the ultrasonic wave is generated in the sub ink tank or to discharge the ink and refresh it. Therefore, if the stirring mechanism 4d is provided as shown in FIG. 3, the above-described maintenance is not necessary, and wasteful ink can be greatly reduced as compared with the case where the ink is refreshed.

As described above, according to the present embodiment, an ink jet recording apparatus that has excellent printing stability, is unlikely to cause printing defects, and can eliminate the accumulation of ink-derived adhesive (cake) can be obtained.
More specifically, by combining stirring and ultrasonic waves, sedimentation can be recovered while maintaining printing stability. In particular, when the stirring mechanism is used alone, the printing stability is adversely affected. However, when combined with the ultrasonic mechanism, the printing stability is better than that when the ultrasonic mechanism is used alone. Show properties. In addition, by applying ultrasonic waves, separation of pigments aggregated due to sedimentation can be quickly achieved. Furthermore, unlike the first embodiment described above, this embodiment can suppress sedimentation in the sub ink tank 2d by providing the sub ink tank 2d having the ultrasonic deaeration mechanism 5d, and a slight deaeration is also possible. In addition, bubbles are less likely to be taken into the ink 3. Furthermore, in the present embodiment, unlike the first embodiment described above, the degree of freedom of the position of the main ink tank 2c is increased by providing the transport pump 9 in the supply path 6.

[Sixth Embodiment]
The sixth embodiment is different from the first embodiment in that a reservoir is provided in the recording device 41 by an ink cartridge mounting portion.
[Liquid ejection device configuration]
FIG. 4 is a schematic diagram illustrating a modified example of the ink jet recording apparatus which is an example of the liquid ejection apparatus according to the present embodiment. The recording device 41 includes a reservoir (ink cartridge) 2e, a stirring mechanism 4e, a drive unit 4ef, an ultrasonic deaeration mechanism 5e, a supply path 6, a check valve 7, a printer head 8, a reservoir mounting unit (ink cartridge mounting unit). ) 10, a stirrer chip 11, a cap 12, an ink outlet 13 and an ink supply needle 15 are provided.

The ink cartridge 2e corresponding to the reservoir is provided in the recording device 41 by the reservoir mounting portion 10 which is an ink cartridge mounting portion, and is for storing the ink 3 to be deaerated. The stirring mechanism 4e includes a stirrer chip 11 and a drive unit 4ef that drives the stirrer chip 11. The agitation mechanism 4e is configured by the ink 3 stored in the reservoir 2e.
Are provided for stirring. The drive part 4ef is a reservoir mounting part 1 outside the reservoir 2e.
0 is provided. The stirrer chip 11 provided inside the reservoir 2e is for stirring the ink 3 without being in contact with the driving unit 4ef, for example, by driving the driving unit 4ef using magnetic force.

A stirrer chip 11 is provided in advance in the ink cartridge 2e. This
Stirring can be performed in a non-contact manner from the drive unit 4ef provided in the reservoir mounting unit 10 outside the ink cartridge 2e. By providing an ultrasonic deaeration mechanism 5e near the printer head supply hole,
Further, it is possible to prevent air bubbles and sediment from flowing into the printer head 8.

The ultrasonic deaeration mechanism 5e is for preventing air bubbles and sediment from flowing into the head.
The ultrasonic deaeration mechanism 5e is provided in the vicinity of the printer head supply hole. For example, the cap 12 which is an ultrasonic generator is for sealing the upper part of the reservoir 2e. On the other hand, an ink supply needle 15 having an ink supply port (not shown) is attached to the ink outlet 13 at the lower part of the reservoir 2e and the lower part of the reservoir attachment part 10. The supply path 6 is for feeding the ink 3. The supply path 6 communicates with the reservoir 2 e through the ink supply needle 15. The supply path 6 may include a liquid feed pump in the middle thereof. The ink 3 is supplied to the printer head 8 through the supply path 6.
The ink supply port (not shown) is positioned below the tip of the ink supply needle 15 (
The position indicated by reference numeral 13 in FIG. 4). Further, the ink outlet 13 is located at a location where the ink supply needle 15 of the outer wall of the ink cartridge penetrates. Reference numeral 15 in FIG. 4 denotes an ink supply needle attached to the ink cartridge mounting unit 10, and the ink is supplied to the head 8 through the supply needle by inserting the ink supply needle into the ink cartridge. The ultrasonic vibration device 5e is connected to the flow path connecting the ink supply needle and the head 8, so that the supplied ink can be ultrasonically degassed. The bottom surface of the ink cartridge mounting portion 10 is provided with a stirring device 4ef for rotating the stirrer 11 in the ink cartridge, and this stirrer normally stirs the magnetic stirrer with a magnetic force.

In each of the above-described embodiments, there are a mode in which ink is supplied from the main ink tank to the printer head without passing through the sub ink tank, and a mode in which ink is supplied from the main ink tank to the printer head via the sub ink tank. is there. In the present invention, whether the reservoir in which ultrasonic degassing by the ultrasonic degassing mechanism and stirring by the stirring mechanism are performed is a main ink tank, or if a sub ink tank is provided, a sub ink tank. It can be at least either. If ultrasonic deaeration and stirring are performed in at least one of the reservoirs, the effect of the present invention can be obtained in the reservoir. The main ink tank may be provided in a carriage on which the printer head is mounted, or may be provided in a place different from the carriage. Further, when the main ink tank is provided at a location different from the carriage, the sub ink tank may be provided at the carriage, or may be provided at a location different from the carriage in the same manner as the main ink tank. Further, as a liquid ejecting apparatus in which the printer head is not mounted on the carriage, for example, a line ink jet printer may be used. In that case, the main ink tank and the sub ink tank are not provided in the carriage.
In this case, the reservoir may be an ink cartridge or any container that is not an ink cartridge. In any of the above-described forms, the main ink tank may be configured as a removable ink cartridge.

[Inkjet recording method (operation)]
FIG. 5 is a flowchart showing an example of an ink jet recording method using the ink jet recording apparatus of the present embodiment. Since this flowchart has already been described in the first embodiment, the description of the contents common to these embodiments is omitted here. Less than,
This embodiment will be described in detail.

(Print command (S10))
The print command instructs image data to be printed and printing. Image data is transmitted from a computer apparatus (not shown) to the ink jet recording apparatus together with a print command.

(Ultrasonic stirring operation (S11))
In general, the ultrasonic stirring operation is as follows: (1) driving of the ultrasonic deaeration mechanism 5e which is, for example, an ultrasonic deaerator (starting of ultrasonic irradiation), (2) starting of stirring, (3) stopping of stirring, The process proceeds in the order of (4) printing, and (5) stop of the ultrasonic deaeration mechanism 5e (stop of ultrasonic irradiation). Note that printing may be performed after the operation (5).

When the ultrasonic wave of (1) is first applied, the precipitate is easily eliminated by the subsequent stirring of (2). By stirring, ultrasonic degassing can be effectively achieved even in the case of ink having a high viscosity. If the stirring is continued, bubbles are taken into the ink 3. Therefore, stirring is stopped while applying ultrasonic waves (above (3)), and ultrasonic deaeration is performed for a while, so that the bubbles are taken into the ink 3 by stirring. Eliminate air bubbles. After printing (4) above, the ultrasonic wave is stopped (above (5)). Note that printing may be started while applying ultrasonic waves. That is, printing may be performed after any operation as long as it is after the operation (3).

(Print (S12))
In printing, (4) printing is performed. Specifically, at least the ejection step (4-1) is performed, and when the ink to be used is an ultraviolet curable ink, the curing step (4-2) is performed.
In addition, since the discharge process and hardening process in this embodiment are the same as that of the said 1st Embodiment, description is abbreviate | omitted here.

  In the flowchart of FIG. 6, an ultrasonic stirring operation is always performed before printing.

In the flowchart of FIG. 7, the ultrasonic stirring operation is performed before printing only when a predetermined time has elapsed since the previous ultrasonic stirring operation.

As described above, according to the present embodiment, an ink jet recording apparatus that has excellent printing stability, is unlikely to cause printing defects, and can eliminate the accumulation of ink-derived adhesive (cake) can be obtained.
More specifically, by combining stirring and ultrasonic waves, sedimentation can be recovered while maintaining printing stability. In particular, when the stirring mechanism is used alone, the printing stability is adversely affected. However, when combined with the ultrasonic mechanism, the printing stability is better than that when the ultrasonic mechanism is used alone. Show the characteristics. In addition, by applying ultrasonic waves, separation of pigments aggregated due to sedimentation can be quickly achieved.
Note that the advantage of the on-carriage method is that it is assumed to be located at the top of the printer head and the flow path to the printer head is short, so there is a difference in flow resistance and water head value when supplying ink to the printer head. Therefore, a system for supplying ink with a pump or the like is not necessary, and as a result, the cost related to the ink supply structure is reduced.

Here, in the ultrasonic operation in the first to sixth embodiments, the bubbles can be removed from the ink by pushing the bubbles upward by the ultrasonic waves, and further, the precipitate is removed by the ultrasonic waves. There is also an effect of stirring. However, in order to break up the hard sediment when the sediment is made into a cake, a stirring mechanism using a screw or the like is provided in addition to the ultrasonic deaeration mechanism. Here, when stirring with a screw in the stirring mechanism, bubbles are mixed in with the screw, so an ultrasonic degassing mechanism is also used. As a stirring means in the stirring mechanism, in addition to the screw, a stirrer piece, a method of stirring the ink by rotating the ink tank itself or shaking may be used. It is preferable to use a strong magnet as the stirrer piece.

〔ink〕
The composition of the ink (hereinafter also referred to as “ink composition”) 3 in the present embodiment is not particularly limited. For example, when the ink is an ultraviolet curable ink, it contains at least a polymerizable compound and a photopolymerization initiator. Further, when the ink is a colored ink other than the clear ink, a color material is also included. Hereinafter, each component contained in or included in the ink composition will be described.

(Polymerizable compound)
The polymerizable compound is not particularly limited as long as it is a compound that polymerizes and solidifies upon irradiation with ultraviolet rays by the action of a photopolymerization initiator described later. For example, various monomers and oligomers having a monofunctional group, a bifunctional group, and a polyfunctional group having three or more functional groups can be used.

Here, the “monomer” in the present specification means a molecule having a weight average molecular weight of 100 to 3,000. As used herein, “oligomer” means a weight average molecular weight of 500 to 20
, 000 molecules.

The monomer is not particularly limited. For example, unsaturated carboxylic acids such as (meth) acrylic acid, itaconic acid, crotonic acid, isocrotonic acid and maleic acid, salts or esters thereof, urethane, amide and anhydrides thereof, Examples include acrylonitrile, styrene, various unsaturated polyesters, unsaturated polyethers, unsaturated polyamides, and unsaturated urethanes.
An N-vinyl compound may be included as another monofunctional monomer or polyfunctional monomer.
N-vinyl compounds include N-vinylformamide, N-vinylcarbazole, N-vinyl
Examples thereof include vinylacetamide, N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, and derivatives thereof.

Examples of the oligomer include oligomers formed from the above monomers such as linear oligomers and hyperbranched oligomers, epoxy (meth) acrylates, aliphatic urethane (meth) acrylates, aromatic urethane (meth) acrylates, poly Examples include ether (meth) acrylate and polyester (meth) acrylate.

Among those listed above, esters of (meth) acrylic acid, that is, (meth) acrylates are preferred. When (meth) acrylate is used as the polymerizable compound, the curability of the ink and the adhesion of the cured film to the adherend can be improved.
In the present specification, “(meth) acrylate” means acrylate and its corresponding methacrylate, and “(meth) acryl” means acryl and its corresponding methacryl.

Among the above (meth) acrylates, monofunctional (meth) acrylates include, for example, isoamyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, iso Myristyl (meth) acrylate, isostearyl (meth) acrylate, 2-ethylhexyl-diglycol (meth) acrylate, 2-hydroxybutyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxydiethylene glycol ( (Meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypropylene glycol (meth) acrylate, phenoxyethyl (meth) acrylate , Tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, lactone-modifiable Examples include flexible (meth) acrylate, t-butylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, and isobornyl (meth) acrylate.

Among the (meth) acrylates, examples of the bifunctional (meth) acrylate include triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, and dipropylene glycol di ( (Meth) acrylate, tripropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonane Diol di (
(Meth) acrylate, neopentyl glycol di (meth) acrylate, dimethylol-
Tricyclodecane di (meth) acrylate, EO (ethylene oxide) adduct of bisphenol A di (meth) acrylate, PO of bisphenol A (propylene oxide)
Examples include adduct di (meth) acrylate, hydroxypivalic acid neopentyl glycol di (meth) acrylate, and polytetramethylene glycol di (meth) acrylate.

Among the above (meth) acrylates, trifunctional or more polyfunctional (meth) acrylates include, for example, trimethylolpropane tri (meth) acrylate, EO-modified trimethylolpropane tri (meth) acrylate, and pentaerythritol tri (meth) acrylate. ,
Pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, glycerin propoxytri (meth) acrylate, cowprolactone-modified trimethylolpropane tri (meth) acrylate, pentaerythritol ethoxy Tetra (meth) acrylate,
And caprolactam-modified dipentaerythritol hexa (meth) acrylate.

Among these, since the stretchability of the coating film (coating layer) at the time of curing is high and has a low viscosity, from the viewpoint that injection stability at the time of ink jet recording is easily obtained, as a polymerizable compound,
It is preferable that monofunctional (meth) acrylate is included. Furthermore, it is more preferable to use a monofunctional (meth) acrylate and a bifunctional (meth) acrylate together from the viewpoint of increasing the hardness of the coating layer.

Among the (meth) acrylates listed above, at least one selected from the group consisting of dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, and 1,6-hexanediol acrylate is preferable. At least one of propylene glycol di (meth) acrylate and tripropylene glycol di (meth) acrylate is more preferable. In this case, since the balance of viscosity, curability, and skin irritation is excellent, it is effective for inkjet inks that are easily affected by viscosity during ejection, and skin irritation is also reduced.
In addition to the (meth) acrylate monomer, the photopolymerizable compound is a conventionally known (meth)
An acrylate oligomer may further be included.

  Said polymeric compound may be used individually by 1 type, and may use 2 or more types together.

(Photopolymerization initiator)
The polymerization initiator is not particularly limited as long as it generates active species such as radicals and cations by the energy of ultraviolet rays and initiates polymerization of the polymerizable compound. A radical polymerization initiator or a cationic polymerization initiator can be used, and among these, it is preferable to use a radical polymerization initiator. By using the radical polymerization initiator, there is no inhibition of polymerization due to humidity as in the case of cationic polymerization, so that an advantageous effect that the printing environment is not selected can be obtained.
In addition, although it does not specifically limit as a cationic polymerization initiator, For example, the chemical amplification type photoresist and the compound utilized for photocationic polymerization are used (Organic Electronics Materials Research Group, "Organic material for imaging", Shin Publishing (1993), pages 187 to 192, Technical Information Association, “Photocuring Technology”, photoacid generator introduced in 2001). Preferred compound examples in the present embodiment, first, a diazonium, ammonium, Yo - Doniumu, aromatic onium compounds sulfonium such as ^{_{B (C 6 F 5) 4}} -, PF 6 -, AsF 6 -, S
^{_{bF 6 -, CF 3 SO 3}} - salts. Those having a borate compound as a counter anion are preferred because of their high acid generation ability. Moreover, the sulfonated substance which generate | occur | produces a sulfonic acid, the halide which photogenerates a hydrogen halide, and an iron allene complex are also mentioned suitably.
Examples of commercially available cationic polymerization initiators include UV1-6992 (triphenylsulfonium salt, manufactured by The Dow Chemical Company).

Examples of the radical polymerization initiator include aromatic ketones, acylphosphine compounds, aromatic onium salt compounds, organic peroxides, thio compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, and azinium compounds. , Metallocene compounds, active ester compounds, compounds having a carbon halogen bond, and alkylamine compounds.

Specific examples of the radical polymerization initiator include acetophenone, acetophenone benzyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, Carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4′-dimethoxybenzophenone, 4,4′-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyldimethyl ketal, 1- (4-isopropylphenyl) 2-hydroxy-2-methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, thioxanthone, diethylthio Sandone, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, bis (2,4,6-trimethylbenzoyl) -phenyl Phosphine oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, 2,4-diethylthioxanthone and bis- (2,6-dimethoxybenzoyl)
Examples include -2,4,4-trimethylpentylphosphine oxide.

Examples of commercially available radical polymerization initiators include IRGACURE 651 (2,2-
Dimethoxy-1,2-diphenylethane-1-one), IRGACURE 184 (1-
Hydroxy-cyclohexyl-phenyl-ketone), DAROCUR 1173 (2-hydroxy-2-methyl-1-phenyl-propan-1-one), IRGACURE 29
59 (1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one), IRGACURE 127 (2-hydroxy-1- {4
-[4- (2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-
Methyl-propan-1-one}, IRGACURE 907 (2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one), IRGACURE 36
9 (2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1), IRGACURE 379 (2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone), DAR
OCUR TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide), IRGACURE 819 (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide), IRGACURE 784 (bis (η5-2,4 -Cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1)
-Yl) -phenyl) titanium), IRGACURE OXE 01 (1.2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)]), IR
GACURE OXE 02 (ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime)), IRGA
CURE 754 (a mixture of oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid, 2- (2-hydroxyethoxy) ethyl ester) (above, Ciba Japan KK), KAYACU
RE DETX-S (2,4-diethylthioxanthone) (Nippon Kayaku
Co., Ltd.), Lucirin TPO, LR8883, LR8970 (above, BA
SF) and Ubekrill P36 (UCB).

The said photoinitiator may be used individually by 1 type, and may be used in combination of 2 or more type.

(Color material)
The ink composition in the present embodiment may further include a color material. The color material is at least one of a pigment and a dye. Among these, the ink (ink jet recording ink) is an example of a liquid because the effect of applying the ink jet recording method characterized by performing ultrasonic deaeration while stirring and the ink jet recording apparatus used for the method is very large. ) Is preferably a liquid composition containing a pigment, more preferably a liquid composition containing a metal oxide, and even more preferably a pigment-based white ink.

(1. Pigment)
In this embodiment, the light resistance of the ink composition can be improved by using a pigment as the color material. As the pigment, both inorganic pigments and organic pigments can be used.

As the inorganic pigment, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black and channel black, iron oxide, and titanium oxide can be used. Among these, as described above, when the pigment-based ink is a white ink, it is preferable to use titanium oxide from the viewpoint of maintaining good whiteness.

Organic pigments include insoluble azo pigments, condensed azo pigments, azo lakes and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments. Polycyclic pigments such as, dye chelates (for example, basic dye chelates, acid dye chelates, etc.), dye lakes (basic dye lakes, acid dye lakes), nitro pigments,
Examples include nitroso pigments, aniline black, and daylight fluorescent pigments.

The said pigment may be used individually by 1 type, and may use 2 or more types together. Further, any pigment not described in the color index can be used as long as it is insoluble in water.

(2. Dye)
In the present embodiment, a dye can be used as the color material. The dye is not particularly limited, and acid dyes, direct dyes, reactive dyes, and basic dyes can be used. Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 14
2, C.I. I. Acid Red 52, 80, 82, 249, 254, 289, C.I. I. Acid Blue 9, 45, 249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I.
Food Black 1, 2, C.I. I. Direct yellow 1, 12, 24, 33, 50, 55
58, 86, 132, 142, 144, 173, C.I. I. Direct red 1, 4, 9
, 80, 81, 225, 227, C.I. I. Direct blue 1, 2, 15, 71, 86,
87, 98, 165, 199, 202, C.I. I. Directed Black 19, 38, 51,
71,154,168,171,195, C.I. I. Reactive Red 14, 32, 55
79, 249, C.I. I. Reactive black 3, 4, and 35 are mentioned.

The ink composition can also be applied to clear ink that does not contain a color material. That is, even in clear ink that does not contain a pigment, excellent printing stability can be achieved by a system having an ultrasonic deaeration process that performs ultrasonic deaeration. In addition to this, the deaeration process can be used more effectively by providing a stirring mechanism. In this case, the deaeration process can obtain the effectiveness more remarkably in the ink having a high viscosity.

Further, the pigment can be used by being dispersed in a dispersant or a surfactant described later.

(Other ingredients)
The ink composition in the present embodiment may contain components other than the components listed above. Although it does not specifically limit as the said component, For example, a dispersing agent is mentioned.

Although it does not specifically limit as said dispersing agent, For example, the dispersing agent currently used for preparing pigment dispersion liquids, such as a polymer dispersing agent, Ajimoto fine techno Co., Ltd. Ajispar series, Abyssia Co., Ltd. Examples include Solspers series manufactured by BYK Chemie, Dispersic series manufactured by BYK Chemie, and Disparon series manufactured by Enomoto Kasei Co., Ltd. The polymer dispersant is not particularly limited, and examples thereof include polyoxyalkylene polyalkylene polyamines, vinyl polymers and copolymers, acrylic polymers and copolymers, polyesters, polyamides, polyimides, polyurethanes, amino polymers, silicon-containing polymers, and the like. The thing which has 1 or more types as a main component among a sulfur polymer, a fluorine-containing polymer, an epoxy resin, etc. is mentioned.

The surfactant is not particularly limited. For example, as a silicone surfactant, a polyester-modified silicone or a polyether-modified silicone can be used.
It is particularly preferable to use polyether-modified polydimethylsiloxane or polyester-modified polydimethylsiloxane. Specific examples include BYK-347, BYK-348, BY
K-UV3500, 3510, 3530, 3570 (BYK Ja
pan KK)).

Further, the ink composition includes a polymerization accelerator, a slip agent, a penetration accelerator, a wetting agent (humectant),
A fixing agent, an antifungal agent, an antiseptic, a surfactant, an antioxidant, a polymerization inhibitor, an ultraviolet absorber, a chelating agent, a pH adjusting agent, and a thickening agent may be included.

[Recording medium]
Examples of the recording medium include an absorptive or non-absorbable recording medium. The ink jet recording method of the present embodiment has various absorption performances from a non-absorbable recording medium in which penetration of the water-soluble ink composition is difficult to an absorbent recording medium in which penetration of the water-soluble ink composition is easy. Widely applicable to recording media.

The absorbent recording medium is not particularly limited. For example, plain paper such as electrophotographic paper having high water-based ink permeability, ink jet paper (an ink absorbing layer composed of silica particles or alumina particles, or polyvinyl alcohol). Art paper and coats used for general offset printing with relatively low permeability of water-based ink from (PVA) and inkjet pyrrole (PVP) and other ink-absorbing layers composed of hydrophilic polymers such as polyvinylpyrrolidone (PVP). Examples thereof include paper and cast paper.

The non-absorbable recording medium is not particularly limited. For example, films and plates of plastics such as polyvinyl chloride, polyethylene, polypropylene, and polyethylene terephthalate (PET), and metals such as iron, silver, copper, and aluminum are used. Examples thereof include a plate, a metal plate produced by vapor deposition of these various metals, a plastic film, a plate made of an alloy such as stainless steel or brass.

[Method of stirring and deaerating ink for inkjet recording]
The present invention also relates to a method for stirring and deaerating ink for inkjet recording. The stirring deaeration method includes ultrasonic deaeration while stirring the inkjet recording ink. The ultrasonic degassing while stirring the ink for ink jet recording overlaps with the content described in the section of the ultrasonic stirring operation in the ink jet recording method (operation) in the first to sixth embodiments. Therefore, explanation here is omitted.

The ink jet recording ink is preferably a pigment-based ink because the effect of applying the ink-jet recording ink stirring / degassing method characterized by performing ultrasonic degassing while stirring is very large. White ink is more preferable. Since the detailed description of ink overlaps with the content described in the section of ink in the first to sixth embodiments, the description thereof is omitted here.

Hereinafter, the embodiments of the present invention will be described more specifically with reference to examples and comparative examples. However, the embodiments of the present invention are not limited to these examples.

[Materials used]
The materials used in the examples and comparative examples are as shown below.
[Ink composition]
(Photopolymerizable compound)
Dipropylene glycol diacrylate (bifunctional monomer, abbreviated as DPGDA in Table 1)
Tripropylene glycol diacrylate (bifunctional monomer, abbreviated as TPGDA in Table 1)
(Photopolymerization initiator)
・ IRGACURE 819 (manufactured by Ciba Japan KK)
・ DAROCUR TPO (Ciba Japan)
・ KAYACURE DETX-S (Nippon Kayaku Co., Ltd.)
(Pigment)
・ Titanium oxide (dispersant)
・ Polyoxyalkylene polyalkylene polyamine (recording medium)
-Transparent PET film PET50A PL Thin 11BL (Lintec Co.,
Ltd.)

[Example 1, Comparative Examples 1-3]
[Production of UV-curable ink composition]
First, a pigment dispersion was prepared. In Table 1 below, pigments and dispersants whose types and blending amounts are described in parts by mass were mixed and stirred. The obtained mixture was subjected to a dispersion treatment for 6 hours together with zirconia beads (diameter 1.5 mm) using a sand mill (manufactured by Yaskawa Seisakusho). Thereafter, the zirconia beads were separated with a separator to obtain a pigment dispersion used in Examples and Comparative Examples.

Next, after preparing a polymerizable compound and a photopolymerization initiator described in Table 1 below in the pigment dispersion obtained above, these materials were mixed and stirred using a stirrer (content unit is % By mass). In this way, an ultraviolet curable white ink composition was obtained.

[Method for producing inkjet recorded matter]
Inkjet recordings were produced using a line printer having the configuration shown in FIG. A reservoir (ink tank) equipped with a stirring mechanism and an ultrasonic deaeration mechanism is filled with the ultraviolet curable ink composition obtained in Production Example 1, and deaerated by stirring while applying ultrasonic waves for 30 minutes. It was. After the ink in the reservoir was supplied to the printer head via the supply path, the ultraviolet curable ink composition was ejected onto the transparent PET film so as to have a film thickness of 10 μm. Then, this transparent PET film was irradiated with a metal halide lamp (irradiation energy: 200 mJ /
cm ² ) cured. In this way, an ink jet recorded matter having white ink printed on a transparent PET film was produced.
The operation up to printing will be described in the following experimental example. The ultrasonic irradiation energy in the ultrasonic degassing mechanism was 30 KHz.

[Measurement / Evaluation Items]
[Evaluation of printing stability]
The above-mentioned ink was filled in a printer head of a line printer having the configuration shown in FIG. 1, and was left as it was for one week after confirming ejection of ink from all nozzles. Then, after operating for 30 minutes with each combination shown in Table 2 below for the stirring mechanism and the ultrasonic deaeration mechanism, 15
After ink was continuously discharged for a minute, solid printing was performed to determine the ratio of the number of missing nozzles. The results are shown in Table 2 below.

[Measurement of whiteness (L ^* value)]
The above-mentioned ink was filled in a printer head of a line printer having the configuration shown in FIG. 1, and was left as it was for one week after confirming ejection of ink from all nozzles. Then, after operating for 30 minutes with each combination shown in Table 2 below for the stirring mechanism and the ultrasonic deaeration mechanism, 15
Ink was continuously discharged for a minute and then solid printing was performed. Inkjet recording is SpectroScan (G
The L ^* value was measured on a black table (manufactured by RATAG) using a Spectrolino (manufactured by GRATAG) to determine the whiteness. In the measurement, when there was a missing dot in the ink jet recorded material, a portion where the missing dot was as small as possible was measured. The results are shown in Table 2 below.

[Evaluation of presence of cake]
After filling the main ink tank with ink, the main ink tank was allowed to stand for one week. Thereafter, the stirring mechanism and the ultrasonic degassing mechanism are 30 in each combination shown in Table 2 below.
After the minute operation, the presence of a cake (adhesive) was confirmed by scratching the bottom surface of the main ink tank with a glass rod. The results are shown in Table 2 below.

From the results of Table 2 above, by using the ink jet recording apparatus of the present invention provided with a reservoir (ink tank) equipped with a stirring mechanism and an ultrasonic deaeration mechanism, the printing stability is excellent and printing defects are hardly caused. In addition, it has been clarified that an ink-jet recorded product can be obtained which can eliminate the accumulation of ink-derived adhesive (cake).
In Comparative Example 2, when there is no stirring mechanism and (ultrasonic) deaeration mechanism, the whiteness is slightly lowered despite the absence of the titanium oxide cake. The reason is as follows. It is. When settling progresses to some extent, a cake is generated. In order to eliminate (redisperse) the cake, it is effective to apply more ultrasonic waves than normal stirring. The influence on the whiteness due to sedimentation is significant at a level that can be eliminated by normal stirring, and is also significant at a level where a cake is not formed. In other words, the effect of the presence or absence of cake can be said to be small. Therefore, it is clear that the dissolution of sediment rather than the cancellation of cake affects the restoration of the whiteness, and in this settlement of dissolution, the effect of the agitation that greatly flows the entire tank rather than the ultrasonic wave is greater. It was.

1, 2, 31, 41 ... recording device, 2a ... reservoir, main ink tank, 2b ... reservoir, sub ink tank, 2c ... reservoir, main ink tank, 2d ... reservoir, sub ink tank, 2e ... storage Container, ink cartridge, 3 ... ink, 4, 4a, 4c, 4d, 4e ...
Stirring mechanism, 4ef ... drive unit, 5, 5a, 5b, 5c, 5d, 5e ... ultrasonic deaeration mechanism, 6 ...
Supply path, 7 ... Check valve, 8 ... Printer head, 9 ... Transport pump, 10 ... Storage container mounting section, ink cartridge mounting section, 11 ... Stirrer chip, 12 ... Cap, 13 ... Ink outlet, 15 ... Ink supply needle.

Claims (7)

A printer head that discharges liquid from a nozzle toward a medium to be discharged;
A discharged medium conveying means for conveying the discharged medium to a position facing the printer head;
A supply path for supplying the liquid to the printer head;
A reservoir in communication with the supply path for storing the liquid;
An ultrasonic degassing mechanism for ultrasonically degassing the liquid in the reservoir;
An agitation mechanism for agitating the liquid in the reservoir;
A liquid ejection apparatus.   The liquid discharge apparatus according to claim 1, wherein the liquid is a liquid composition containing a metal oxide. The liquid ejecting apparatus according to claim 1, wherein the printer head is provided on a carriage, and the reservoir is provided on the carriage. The liquid ejecting apparatus according to claim 1, wherein the printer head is provided in a carriage, and the reservoir is provided in a place other than the carriage. The liquid ejecting apparatus according to claim 1, wherein the reservoir is a liquid cartridge. The liquid discharge apparatus according to claim 1, further comprising a transport pump provided in the supply path. A liquid agitation and deaeration method for use in a liquid ejection apparatus, comprising ultrasonically deaeration while stirring the liquid used in the liquid ejection apparatus according to claim 1.