JP2023019841A - Liquid ejector - Google Patents

Abstract

Kind Code: A1 In a liquid ejection apparatus that ejects ink that is cured by being irradiated with an active energy ray from a liquid ejection head, there is a problem that the ejection performance of the ink deteriorates when the ink is not ejected for a while.
SOLUTION: First and second inks that are cured by being irradiated with an active energy ray, a liquid ejection head that ejects the liquid, and supply control means that controls the supply of the liquid to the liquid ejection head. wherein the first and second inks are the same color, the curability of the first ink is lower than the curability of the second ink, and the liquid ejection head at the start of printing has the first and the liquid ejection head is filled with the first ink at the end of printing, and the supply control means starts supplying the second ink to the liquid ejection head after printing is started, Further, the liquid ejection device starts supplying the first ink to the liquid ejection head after starting the supply of the second ink and before the end of printing.
[Selection drawing] Fig. 5

Description

The present invention relates to a liquid ejection device.

2. Description of the Related Art In recent years, attention has been paid to an ink jet recording method using an active energy ray-curable ink. In this method, generally, ink filled in an inkjet head is ejected from a nozzle, and then the ink is irradiated with ultraviolet rays to form a cured product.

As an inkjet recording method using active energy ray-curable ink, for example, in Patent Document 1, for the purpose of being able to print the inkjet ink on a wide variety of ink-receptors with consistent image quality, a) the same color and providing to an inkjet printer two or more pigmented colored inkjet inks having color densities but different compositions; b) mixing said two or more pigmented colored inkjet inks in a controlled amount; and c. ) printing a mixture of said two or more pigmented color inkjet inks with an inkjet printer onto an ink receiver.

However, in a liquid ejection apparatus that ejects ink that is cured by being irradiated with an active energy ray from a liquid ejection head, there is a problem that the ejection performance of the ink deteriorates when the ink is not ejected for a while due to the suspension of the apparatus or the like. be.

The present invention provides a first ink and a second ink that are cured by being irradiated with an active energy ray, a liquid ejection head that ejects a liquid, and a supply control that controls the supply of the liquid to the liquid ejection head. means, wherein the first ink and the second ink are the same color, the curability of the first ink is lower than the curability of the second ink, and printing is performed. The liquid ejection head at the start of printing is filled with the first ink, and the liquid ejection head at the end of printing is filled with the first ink. starting the supply of the second ink to the liquid ejection head; and further, supplying the first ink to the liquid ejection head after starting the supply of the second ink and before the end of printing. It relates to a liquid ejecting apparatus characterized by starting the supply of the liquid.

According to the present invention, there is provided a liquid ejection apparatus that suppresses deterioration in ink ejection performance even when ink that is cured by being irradiated with an active energy ray is not ejected from the liquid ejection head for a while. be able to.

FIG. 1 is a schematic diagram showing an example of a liquid ejection device according to the first embodiment. FIG. 2 is a schematic diagram showing an example of the configuration of supply control means. FIG. 3 is a schematic diagram showing an example of a liquid ejection device according to the second embodiment. FIG. 4 is a flowchart showing an example of ink supply control in the first embodiment. FIG. 5 is an example of a time chart in which the horizontal axis is time and the vertical axis is the amount of ink filled in the liquid ejection head (filling amount). FIG. 6 is an example of a time chart in which the horizontal axis represents time, and the vertical axis represents the amount of light emitted from the irradiation means and the conveying speed of the recording medium.

<<Liquid Ejector>>
Hereinafter, embodiments of the liquid ejecting apparatus of the present invention will be described.

<First Embodiment>
The liquid ejection apparatus according to the first embodiment includes first ink and second ink that are cured by being irradiated with an active energy ray, a liquid ejection head that ejects liquid, and liquid to the liquid ejection head. and supply control means for controlling supply. In addition, other means or configurations may be provided as required.

FIG. 1 is a schematic diagram showing an example of a liquid ejection device according to the first embodiment. The liquid ejection apparatus of this embodiment transports the recording medium 2 along a transport path provided between the feeding section 1 and the winding section 6 . The transport roller 3 transports the recording medium 2 in contact with the recording medium 2 . The ejection section 4, which is an example of a liquid ejection head, ejects ink that is cured by being irradiated with an active energy ray, which is an example of a liquid, onto the recording medium 2. FIG.

The ejection part ejection part 4 can be filled with any ink that cures when irradiated with an active energy ray, for example, black ink, cyan ink, magenta ink, yellow ink, clear ink, and white ink. It can be appropriately selected from ink and the like. In the example shown in FIG. 1, the ejection section 4 is an inkjet head. The inkjet head may be a line head system or a serial head system, but the line head system is preferable. In the example shown in FIG. 1, a line head system is used.

The recording medium 2 onto which the ink has been ejected passes under the ejection section 4, and is then irradiated with active energy rays by the irradiation section 5, which is an example of irradiation means for irradiating active energy rays. The active energy ray is not particularly limited as long as it can impart the energy necessary to proceed with curing (polymerization reaction) in the ink. Examples include X-rays, but ultraviolet rays are preferred. Irradiation means for irradiating ultraviolet rays include, for example, an ultraviolet light emitting diode (UV-LED) and an ultraviolet laser diode (UV-LD).

The amount of light emitted by the irradiation unit 5 is controlled by the light amount control means 50 . As the light quantity control means 50, CPU is mentioned, for example.

The liquid ejecting apparatus has an ink station 10, and the ink station 10 has a containing portion 11 containing a first ink and a containing portion 12 containing a second ink.

The first ink contained in the containing portion 11 and the second ink contained in the containing portion 12 are supplied to the sub-tank 20 through the flow path, and supplied from the sub-tank 20 to the ejection portion 4 . The liquid ejection device also has an electromagnetic valve 9 , and the electromagnetic valve 9 switches between the first ink and the second ink to be supplied to the sub-tank 20 .

The location of the electromagnetic valve 9 can be selected as appropriate, but it is preferable that it be located immediately before the sub-tank 20 (before ink enters the sub-tank) as shown in FIG. By installing the solenoid valve 9 immediately before the sub-tank 20, it is possible to suppress the pressure fluctuation due to the switching of the valve.

Switching of the valve by the electromagnetic valve 9 (in other words, switching between the first ink and the second ink supplied to the sub-tank 20) is controlled by the supply control means 90. FIG. The supply control means 90 is, for example, a CPU.
Note that the supply control means will be described in detail with reference to FIG. FIG. 2 is a schematic diagram showing an example of the configuration of supply control means. As shown in FIG. 2, the supply control unit 90 includes a job determination unit 91 that determines the progress state of the print job and whether or not there is a print job, and information regarding switching of the electromagnetic valve based on the determination result of the job determination unit 91. to the solenoid valve driver 93 to control switching of the solenoid valve 9 .

The first ink and the second ink contained in the containing portion 11 and the containing portion 12 are of the same color, and the curability of the first ink is lower than that of the second ink.
In the case where the first ink and the second ink are the same color, it is sufficient if the colors of the first ink and the second ink are recognized as being the same color according to social convention. It is not limited to the case where it is determined that the color is completely the same in the case of For example, if the first ink and the second ink are both sold or distributed as magenta ink, it is determined that the first ink and the second ink have the same color.
The method for comparing the curability of inks is not particularly limited, but one example is a method of testing physical properties on the surface of cured inks formed under the same printing conditions. Examples of methods for testing the physical properties of the surface of the cured ink include a method of rubbing the surface with a cotton swab or the like, and confirming the presence or absence of scratches formed on the surface, the presence or absence of stickiness, and the like. Another example is a method of measuring the degree of polymerization in a cured product of ink formed under the same printing conditions. The method for measuring the degree of polymerization in the cured ink is not particularly limited, but examples thereof include a method of measuring by infrared spectroscopy. Specifically, the peak value of 820 to 800 cm ⁻¹ corresponding to =CH out-of-plane bending vibration, the peak value of 1430 to 1400 cm ⁻¹ corresponding to =CH in-plane bending vibration, or C=C corresponding to C It is calculated by reading the peak value at 1640 to 1620 cm ⁻¹ and comparing it with the value when not cured (when not irradiated).

As described above, the curability of the first ink is lower than that of the second ink. is preferably three times or more. In addition, in the present disclosure, the integrated amount of light required for curing the ink is obtained as follows. First, by irradiating the ink with an active energy ray with a predetermined illuminance, the ink is cured to a state where the surface is neither scratched nor sticky when the surface of the cured product is rubbed with a cotton swab. Next, by multiplying the illuminance (mW/cm ² ) of the active energy ray irradiated until reaching the state and the irradiation time (seconds), the integrated amount of light (mJ/cm ² ) is calculated. The illuminance is measured with an illuminometer.

<Second embodiment>
A liquid ejection apparatus according to a second embodiment includes a first ink set and a second ink set each having a plurality of inks that are cured by being irradiated with an active energy ray, a liquid ejection head that ejects liquid, and and supply control means for controlling supply of the liquid to the liquid ejection head. In addition, other means or configurations may be provided as required. Descriptions of the same means or configurations as in the first embodiment will be omitted.

FIG. 3 is a schematic diagram showing an example of a liquid ejection device according to the second embodiment. The liquid ejection apparatus of this embodiment has an ink station 10a and an ink station 10b. The ink station 10a has a storage section 11a that stores the inks that make up the first ink set and a storage section 12a that stores the inks that make up the second ink set. The ink station 10b has a storage section 11b that stores the inks that make up the first ink set and a storage section 12b that stores the inks that make up the second ink set.

The ink forming the first ink set contained in the containing portion 11a and the ink forming the second ink set contained in the containing portion 12a are supplied to the sub-tank 20a through the flow path. is supplied to the ejection portion 4a from the In addition, the liquid ejection device has an electromagnetic valve 9a, and the electromagnetic valve 9a switches between the ink forming the first ink set and the ink forming the second ink set to be supplied to the sub-tank 20a.

The ink forming the first ink set contained in the containing portion 11b and the ink forming the second ink set contained in the containing portion 12b are supplied to the sub-tank 20b via the flow path, and the sub-tank 20b is supplied to the sub-tank 20b. is supplied to the ejection portion 4b from the In addition, the liquid ejection device has an electromagnetic valve 9b, and the electromagnetic valve 9b is used to switch between the ink forming the first ink set and the ink forming the second ink set to be supplied to the sub-tank 20b.

The first ink set and the second ink set each have at least one corresponding ink of the same color. Specifically, it represents a case where there are one or more combinations of inks of the same color as the combination of the inks forming the first ink set and the inks forming the second ink set. More specifically, for example, if the first ink set has magenta ink, cyan ink, yellow ink, and black ink, the second ink set contains magenta ink of the same color as the first ink set. ink, cyan ink, yellow ink, and black ink.
When the inks that make up the first ink set and the inks that make up the second ink set are of the same color, the colors of the inks that make up the first ink set and the inks that make up the second ink set are In general, it is sufficient if the colors are recognized as the same color, and the color is not limited to being completely the same color when measured by a predetermined measuring device. For example, when the inks that make up the first ink set and the inks that make up the second ink set are both sold or distributed as magenta ink, the inks that make up the first ink set and the inks that make up the second ink set are judged to be of the same color.

The ink stored in the plurality of storage units that supply ink to the same ejection unit has the same color. Specifically, the ink forming the first ink set contained in the containing portion 11a that supplies ink to the ejection portion 4a and the ink forming the second ink set contained in the containing portion 12a are of the same color. is. Similarly, the ink forming the first ink set contained in the containing portion 11b that supplies ink to the ejection portion 4b and the ink forming the second ink set contained in the containing portion 12b are of the same color. .

When comparing corresponding inks of the same color in the first ink set and the second ink set, the curability of the ink of the first ink set is lower than the curability of the ink of the second ink set. . Specifically, the curability of the ink forming the first ink set contained in the containing portion 11a is lower than the curability of the ink forming the second ink set contained in the containing portion 12a. Similarly, the curability of the ink forming the first ink set contained in the containing portion 11b is lower than the curability of the ink forming the second ink set contained in the containing portion 12b.
As a method for comparing the curability of the inks forming the ink set, the same method as the method described in the first embodiment can be used.

<Control example>
Next, an example of control in the liquid ejecting apparatus of the present invention will be described.
First, an example of ink supply control will be described with respect to the embodiment (first embodiment) shown in FIG. This embodiment is an example having a first ink and a second ink. The first ink and the second ink are the same color, and the curability of the first ink is lower than the curability of the second ink.

First, an example of control will be described with reference to FIG. FIG. 4 is a flowchart showing an example of ink supply control in the first embodiment.
In the present embodiment, the first ink is filled in the liquid ejection head of the liquid ejection device from before the start of printing to when the printing is started. When a print job is received in such a liquid ejecting apparatus, printing is started (S1). Next, after the start of printing (preferably along with the start of printing), the supply control means in the liquid ejection device starts supplying the second ink to the liquid ejection head. to suppress or stop the supply of the first ink (S2). Next, the job judging section in the supply control means judges the progress of the print job, and if it judges that the printing is not yet finished (No in S3), the supply of the second ink is continued. On the other hand, if it is determined that the printing is not yet finished (Yes in S3), the job determination unit in the supply control means determines whether or not there is a next print job, and determines that there is a next print job. (In the case of No in S4), the supply of the second ink is continued. On the other hand, if it is determined that there is no next print job (Yes in S4), the supply control means in the liquid ejecting apparatus starts supplying the first ink to the liquid ejecting head. The supply of the second ink to the liquid ejection head is suppressed or stopped (S5). After that, the printing is finished, and the liquid ejection head is filled with the first ink again from the time when the printing is finished to the time after the printing is finished.

The above will be further described with reference to FIG. FIG. 5 is an example of a time chart in which the horizontal axis is time and the vertical axis is the amount of ink filled in the liquid ejection head (filling amount). In FIG. 5, the solid line indicates the filling amount of the first ink, and the broken line indicates the filling amount of the second ink.

(a) to (e) of FIG. 5 are as follows.
(a) When printing is started after receiving a print instruction (also referred to as "at the start of printing")
(b) When the liquid ejection head is filled with the maximum amount of the second ink (also referred to as “at the time of completion of replacement (1)”)
(c) Time to start supplying the first ink toward the end of printing (also referred to as "before the end of printing")
(d) When the liquid ejection head is filled with the maximum amount of the first ink (also referred to as “at the time of completion of replacement (2)”)
(e) When printing is finished (also referred to as "when printing is finished")
The period before (a) is called "before printing", the period between (a) to (e) is called "during printing", and the period after (e) is called "after printing". Also, the period from (a) to (b) is referred to as "initial stage of printing", the period from (b) to (c) is referred to as "middle stage of printing", and the period from (c) to (d) is referred to as "late stage of printing". , and the period from (d) to (e) is called "printing end".

As shown in FIG. 5, before the start of printing (before (a)), the liquid ejection head is filled with the first ink. On the other hand, before printing is started, the second ink is not filled in the liquid ejection head, or even if it is filled, the amount is very small. As described above, the curability of the first ink is less than the curability of the second ink, ie, the first ink is less curable than the second ink. As a result, it is possible to suppress hardening of the ink in or near the nozzles due to external light or the like when the apparatus is stopped before printing starts. Thus, it is possible to provide a liquid ejecting apparatus that suppresses deterioration in ink ejection performance.

Next, in the initial stage of printing (between (a) and (b)) after the start of printing, supply of the second ink to the liquid ejection head is started along with the start of printing. As a method of supplying the second ink, for example, the method of switching the electromagnetic valve 9 to supply the second ink from the storage section 12 of the ink station 10 can be mentioned as described above. As a result, as shown in FIG. 5, the filling amount of the second ink in the liquid ejection head is increased, the curability of the ink during printing is improved, and the productivity is improved.
Note that the liquid ejection head is filled with the first ink before the start of printing. decreases.

In this manner, in the initial stage of printing (between (a) and (b)) after the start of printing, the filling amount of the first ink in the liquid ejection head decreases and the filling amount of the second ink increases. Then, (b) the liquid ejection head is filled with the maximum amount of the second ink (replacement completion time (1)). Note that the first ink is mainly ejected during the initial stage of printing (between (a) and (b)), and the second ink is mainly ejected during the middle stage of printing (between (b) and (c)). However, since the first ink and the second ink are of the same color, problems in image quality are less likely to occur.

Next, in the latter half of printing (between (c) to (d)), the supply of the first ink to the liquid ejection head is started toward the end of printing. As a method of supplying the first ink, for example, the method of switching the solenoid valve 9 and supplying the first ink from the storage section 11 of the ink station 10 can be mentioned as described above. As a result, as shown in FIG. 5, the filling amount of the first ink increases in the liquid ejection head.
It should be noted that the timing before the end of printing (C) can be selected as appropriate. For example, since the amount of ink to be used can be grasped from the chart to be printed, there is a timing at which the filling amount of the first ink in the sub-tank and the liquid ejection head can be maximized.

Thus, in the latter half of printing (between (c) and (d)), the filling amount of the second ink in the liquid ejection head decreases and the filling amount of the first ink increases. Then, (d) the liquid ejection head is filled with the maximum amount of the first ink (when replacement is completed (2)). It is preferable that the replacement completion time (2) is before (e) the printing end time. As a result, the nozzles of the liquid ejection head can be filled with the first ink when the apparatus is stopped (after printing), and the ink can be prevented from curing in or near the nozzles by external light or the like. As a result, it is possible to provide a liquid ejection apparatus that suppresses deterioration of ink ejection performance even when ink is not ejected from the liquid ejection head for a while. However, printing may be finished before the liquid ejection head is filled with the maximum amount of the first ink. In this case, it is preferable to perform ejection that does not contribute to image formation while supplying the first ink so that the inside of the liquid ejection head is filled with the first ink.
As a method other than the present invention for suppressing the curing of the ink in or near the nozzles due to external light or the like when the apparatus is not in use, for example, cleaning liquid or pure water is used instead of the ink in the liquid ejection head. A filling method can be mentioned. However, such a method consumes ink, cleaning liquid, water, etc., and furthermore, the downtime until the start of printing increases, so the method of the present invention is superior.

Then, after the end of printing (between (d) and (e)), printing ends ((e) at the end of printing). At the end of printing, the second ink is not filled in the liquid ejection head, or the amount of the second ink is very small even if it is filled. Note that the second ink is mainly ejected in the latter stage of printing (between (c) and (d)), and the first ink is mainly ejected in the final stage of printing (between (d) and (e)). However, since the first ink and the second ink are of the same color, problems in image quality are less likely to occur.

Note that in the present embodiment, even if (c) the supply of the first ink is started toward the end of printing before (b) the liquid ejection head is filled with the maximum amount of the second ink. good.
Further, at the time point (b) when the liquid ejection head is filled with the maximum amount of the second ink, the inside of the liquid ejection head is not limited to the case where the inside of the liquid ejection head is completely filled with the second ink. It may be filled with ink. Similarly, when the liquid ejection head is filled with the maximum amount of the first ink in (d), it is not limited to the case where the inside of the liquid ejection head is completely filled with the first ink. of ink may be filled.
Also, the "filling amount of ink in the liquid ejection head" in the time chart shown in FIG. 5 can be obtained from the ink supply speed to the liquid ejection head and the ink volume in the liquid ejection head. The volume of ink in the liquid ejection head can be obtained from the sizes of the ink channels and liquid chambers in the liquid ejection head.

Also, the embodiment (second embodiment) shown in FIG. 3 can be similar to the time chart shown in FIG. In the present embodiment, the ink filling amount in the liquid ejection head in the time chart of FIG. 5 is the filling amount for each ink of the ink set. For example, when two liquid ejection heads are provided as shown in FIG. 3, each liquid ejection head is controlled as shown in the time chart.

Next, an example of controlling the irradiation light amount of the active energy ray by the irradiation means will be described with respect to the embodiment (first embodiment) shown in FIG.
In the first embodiment, the light amount control means can control the amount of irradiation light when printing using the first ink to be higher than the amount of irradiation light when printing using the second ink. preferable.

The above will be described with reference to FIG. FIG. 6 is an example of a time chart in which the horizontal axis represents time, and the vertical axis represents the amount of light emitted from the irradiation means and the conveying speed of the recording medium. In FIG. 6, the amount of irradiation light is indicated by a solid line, and the conveying speed is indicated by a broken line. Also, (a) to (e) in FIG. 6 correspond to (a) to (e) in FIG.

In the time chart of this embodiment, in the initial period between (a) and (b), the first ink with low curability is mainly ejected, so the amount of irradiation light is set to be high. After that, along with the start of supply of the second ink to the liquid ejection head (as the ejected ink replaces the first ink with the highly curable second ink), the irradiation light amount is gradually reduced. Decrease.

Next, between (b) and (c), since the second ink with high curability is mainly ejected, the amount of irradiation light is kept low. Thereby, energy consumption in the irradiation means can be reduced.

Next, in the initial period between (c) to (d), since the second ink having high curability is mainly ejected, the amount of irradiation light is set to be low. After that, along with the start of supply of the first ink to the liquid ejection head (as the second ink is replaced with the first ink, which is less curable), the amount of irradiation light is gradually reduced. increase.

Next, between (d) and (e), since the first ink with low curability is mainly ejected, the amount of irradiation light is kept high.

In addition, in the time chart of this embodiment, the conveying speed is constant.

Also, the embodiment (second embodiment) shown in FIG. 3 can be similar to the time chart shown in FIG. For example, when there are two irradiation means as shown in FIG. 3, each irradiation means is controlled as shown in the time chart.

<Ink>
The first and second inks used in the first embodiment, and the inks forming the first ink set and the second ink set used in the second embodiment will be described. When describing without distinguishing between them, they are simply referred to as ink in the following description. In addition, when the first ink and the inks constituting the first ink set are described without distinguishing between them, in the following description, they are referred to as inks with low curing properties, and the inks constituting the second ink and the second ink set When the description is made without distinguishing the inks, they are referred to as highly curable inks in the following description.

The ink is a liquid composition that cures when exposed to active energy rays, and contains a polymerizable compound and a polymerization initiator, and optionally a polymerization inhibitor, a pigment, a dispersant, and other components.

-Polymerizable compound-
The polymerizable compound is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include polymerizable unsaturated monomer compounds and polymerizable oligomers.

--Polymerizable Unsaturated Monomer Compound--
The polymerizable unsaturated monomer compound is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include polymerizable unsaturated monomer compounds and polymerizable unsaturated monomer compounds having a tetrafunctional or higher functionality. These may be used individually by 1 type, or may use 2 or more types together.

Examples of monofunctional polymerizable unsaturated monomer compounds include 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, benzyl acrylate, phenoxyethyl acrylate, isobornyl acrylate, phenyl Glycol monoacrylate, cyclohexyl acrylate, acryloylmorpholine, tetrahydrofurfuryl acrylate, 4-hydroxybutyl acrylate, 2-methyl-2-ethyl-1,3-dioxolan-4-ylmethyl acrylate and the like. These may be used individually by 1 type, or may use 2 or more types together.

Examples of bifunctional polymerizable unsaturated monomer compounds include 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, tripropylene glycol diacrylate, and tetraethylene glycol. diacrylate, dimethyloltricyclodecane diacrylate, and the like. These may be used individually by 1 type, or may use 2 or more types together.

Examples of trifunctional polymerizable unsaturated monomer compounds include trimethylolpropane triacrylate, pentaerythritol triacrylate, and tris(2-hydroxyethyl)isocyanurate triacrylate. These may be used individually by 1 type, or may use 2 or more types together.

Tetra- or higher-functional polymerizable unsaturated monomer compounds include, for example, pentaerythritol tetraacrylate, ditrimethylolpropane tetraacrylate, dipentaerythritol hydroxypentaacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol hexaacrylate. These may be used individually by 1 type, or may use 2 or more types together.

As the polymerizable unsaturated monomer compound, a polyfunctional polymerizable unsaturated monomer compound can increase the curing rate more than a monofunctional polymerizable unsaturated monomer compound. Volume shrinkage may increase. Therefore, it is preferable to use a polymerizable unsaturated monomer compound that can have a viscosity as low as possible.

The volume shrinkage rate of the cured product of the polymerizable unsaturated monomer compound is preferably 15% by volume or less, more preferably 8% by volume or less.

The skin irritation (P.I.I.) of the polymerizable unsaturated monomer compound is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1.0 or less. When the skin irritation is 1.0 or less, irritation to the skin can be reduced and safety can be improved.

As for the hue of the polymerizable unsaturated monomer compound, the Gardner gray scale is preferably 2 or less, more preferably colorless and transparent. When the Gardner gray scale is 2 or less, it is possible to prevent the color of the image portion from changing. The Gardner gray scale can be measured in accordance with JIS-0071-2 (Method for testing color of chemical products-Method for testing Gardner color number).

The content of the polymerizable unsaturated monomer compound is preferably 50% by mass or more and 90% by mass or less, more preferably 65% by mass or more and 85% by mass or less, relative to the mass of the ink.

--Polymerizable Oligomer--
The polymerizable oligomer preferably has one or more ethylenically unsaturated double bonds. In addition, an oligomer means a polymer having a repeating number of monomer structural units of 2 or more and 20 or less. The weight-average molecular weight of the polymerizable oligomer is not particularly limited and can be appropriately selected according to the purpose. more preferred. A weight average molecular weight can be measured by a gel permeation chromatography (GPC), for example.

Examples of polymerizable oligomers include urethane acrylic oligomers (eg, aromatic urethane acrylic oligomers, aliphatic urethane acrylic oligomers, etc.), epoxy acrylate oligomers, polyester acrylate oligomers, and other special oligomers. These may be used individually by 1 type, or may use 2 or more types together. Among these, oligomers having 2 to 5 unsaturated carbon-carbon bonds are preferable, and oligomers having 2 unsaturated carbon-carbon bonds are more preferable. Good curability can be obtained when the number of unsaturated carbon-carbon bonds is 2 or more and 5 or less.

Commercially available products can be used as the polymerizable oligomer. Examples of commercially available products include UV-2000B, UV-2750B, UV-3000B, UV-3010B, UV-3200B manufactured by Nippon Synthetic Chemical Industry Co., Ltd. UV-3300B, UV-3700B, UV-6640B, UV-8630B, UV-7000B, UV-7610B, UV-1700B, UV-7630B, UV-6300B, UV-6640B, UV-7550B, UV-7600B, UV- 7605B, UV-7610B, UV-7630B, UV-7640B, UV-7650B, UT-5449, UT-5454; ＣＮ９６３、ＣＮ９６３Ａ８０、ＣＮ９６３Ｂ８０、ＣＮ９６３Ｅ７５、ＣＮ９６３Ｅ８０、ＣＮ９６３Ｊ８５、ＣＮ９６４、ＣＮ９６５、ＣＮ９６５Ａ８０、ＣＮ９６６、ＣＮ９６６Ａ８０、ＣＮ９６６Ｂ８５、ＣＮ９６６Ｈ９０、ＣＮ９６６Ｊ７５、ＣＮ９６８、ＣＮ９６９、ＣＮ９７０、ＣＮ９７０Ａ６０、ＣＮ９７０Ｅ６０、ＣＮ９７１、ＣＮ９７１Ａ８０、ＣＮ９７１Ｊ７５、ＣＮ９７２、ＣＮ９７３、ＣＮ９７３Ａ８０、 ＣＮ９７３Ｈ８５、ＣＮ９７３Ｊ７５、ＣＮ９７５、ＣＮ９７７、ＣＮ９７７Ｃ７０、ＣＮ９７８、ＣＮ９８０、ＣＮ９８１、ＣＮ９８１Ａ７５、ＣＮ９８１Ｂ８８、ＣＮ９８２、ＣＮ９８２Ａ７５、ＣＮ９８２Ｂ８８、ＣＮ９８２Ｅ７５、ＣＮ９８３、ＣＮ９８４、ＣＮ９８５、ＣＮ９８５Ｂ８８、ＣＮ９８６、ＣＮ９８９、ＣＮ９９１、ＣＮ９９２、ＣＮ９９４、ＣＮ９９６、ＣＮ９９７、 ＣＮ９９９、ＣＮ９００１、ＣＮ９００２、ＣＮ９００４、ＣＮ９００５、ＣＮ９００６、ＣＮ９００７、ＣＮ９００８、ＣＮ９００９、ＣＮ９０１０、ＣＮ９０１１、ＣＮ９０１３、ＣＮ９０１８、ＣＮ９０１９、ＣＮ９０２４、ＣＮ９０２５、ＣＮ９０２６、ＣＮ９０２８、ＣＮ９０２９、ＣＮ９０３０、ＣＮ９０６０、ＣＮ９１６５、ＣＮ９１６７、ＣＮ９１７８、ＣＮ９２９０、 CN9782, CN9783, CN9788, CN9893; EBECRYL210, EBECRYL220, EBECRYL230, EBECRYL270, KRM8200, EBECRYL5129 manufactured by Daicel Cytec Co., Ltd. , EBECRYL8210, EBECRYL8301, EBECRYL8804, EBECRYL8807, EBECRYL9260, KRM7735, KRM8296, KRM8452, EBECRYL4858, EBECRYL8402, EBECRYL9270, EBECRYL8311, EBECRYL8311, EBECRYL8311, and the like. These may be used individually by 1 type, or may use 2 or more types together. Further, instead of commercial products, synthetic products obtained by synthesis can be used, and synthetic products and commercial products can also be used in combination.

The skin irritation (P.I.I.) of the polymerizable oligomer is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 1.0 or less. When the skin irritation is 1.0 or less, irritation to the skin can be reduced and safety can be improved.

As for the hue of the polymerizable oligomer, the Gardner gray scale is preferably 2 or less, more preferably colorless and transparent. When the Gardner gray scale is 2 or less, it is possible to prevent the color of the image portion from changing. The Gardner gray scale can be measured in accordance with JIS-0071-2 (Method for testing color of chemical products-Method for testing Gardner color number).

The content of the polymerizable oligomer is preferably 10% by mass or less, more preferably 9% by mass or less, even more preferably 8% by mass or less, and particularly preferably 5% by mass or less, relative to the mass of the ink. When the content is 10% by mass or less, the hardness of the resulting cured product can be increased.

-Polymerization initiator-
Any polymerization initiator may be used as long as it can generate active species such as radicals and cations by the energy of active energy rays to initiate polymerization of polymerizable compounds (monomers and oligomers). As such polymerization initiators, known radical polymerization initiators and cationic polymerization initiators can be used singly or in combination of two or more. Among them, radical polymerization initiators are preferably used.

Examples of radical polymerization initiators include aromatic ketones, acylphosphine oxide compounds, aromatic onium salt compounds, organic peroxides, thio compounds (thioxanthone compounds, thiophenyl group-containing compounds, etc.), hexaarylbiimidazole compounds, Examples include ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamine compounds. These may be used individually by 1 type, or may use 2 or more types together. Among these, it is preferable to select according to the wavelength characteristics of the exposure lamp for curing, such as a mercury lamp, a metal halide lamp, and a UV-LED lamp, and a thio compound is preferable because it is less susceptible to oxygen inhibition when forming a thin film, and a thioxanthone compound. (Thioxanthone-based polymerization initiator) is more preferred.

Commercially available products can be used as the polymerization initiator, and examples of commercially available products include Irgacure 819, Irgacure 369, Irgacure 907, Darocur ITX, Lucilin TPO, and Vicure 10 and 30 available from Stauffer Chemical. is mentioned. These may be used individually by 1 type, or may use 2 or more types together.

Commercially available products can be used as the thioxanthone-based polymerization initiator. Commercially available products include, for example, Speedcure DETX (2,4-diethylthioxanthone) and Speedcure ITX (2-isopropylthioxanthone) (manufactured by Lambson). and KAYACURE DETX-S (2,4-diethylthioxanthone) (manufactured by Nippon Kayaku Co., Ltd.).

In addition, as a polymerization initiator, (i) high absorption efficiency of active energy rays, (ii) high solubility in polymerizable unsaturated monomer compounds, (iii) low odor, yellowing, and toxicity, ( iv) Those having characteristics such as no dark reaction are preferred.

The ratio (% by mass) of the mass of the polymerization initiator contained in the low-curability ink to the mass of the low-curability ink is the ratio (% by mass) of the mass of the polymerization initiator contained in the high-curability ink. It is preferably 50% or less, more preferably 40% or less, even more preferably 30% or less, and 20% or less relative to the mass ratio (mass%) of the highly resistant ink. is particularly preferred. Thereby, a difference in curability can be provided between the inks.

Specifically, when using a low-curing ink, the content of the polymerization initiator is preferably 0.5% by mass or more and 10.0% by mass or less with respect to the mass of the ink, and 1.0% by mass. It is more preferable that the content is 5.0% by mass or more.
Further, when using highly curable ink, the content of the polymerization initiator is preferably 3.0% by mass or more and 25.0% by mass or less, and 5.0% by mass or more and 21.0% by mass or more, based on the mass of the ink. 0% by mass or less is more preferable.

In addition to the polymerization initiator, a polymerization accelerator can also be used in combination. The polymerization accelerator is not particularly limited, but examples include ethyl p-dimethylaminobenzoate, 2-ethylhexyl p-dimethylaminobenzoate, methyl p-dimethylaminobenzoate, 2-dimethylaminoethyl benzoate, p -Amine compounds such as butoxyethyl dimethylaminobenzoate. These may be used individually by 1 type, or may use 2 or more types together.

-Polymerization inhibitor-
Examples of polymerization inhibitors include 4-methoxy-1-naphthol, methylhydroquinone, hydroquinone, t-butylhydroquinone, di-t-butylhydroquinone, methoquinone, 2,2′-dihydroxy-3,3′-di(α -methylcyclohexyl)-5,5′-dimethyldiphenylmethane, p-benzoquinone, di-t-butyldiphenylamine, 9,10-di-n-butoxycyanthracene, 4,4′-[1,10-dioxo-1, 10-decanediylbis(oxy)]bis[2,2,6,6-tetramethyl]-1-piperidinyloxy, p-methoxyphenol, 2,6-di-tert-butyl-p-cresol, etc. .

The content of the polymerization inhibitor is preferably 0.005% by mass or more and 3.0% by mass or less with respect to the total amount of the polymerization initiator. When the content is 0.005% by mass or more, the storage stability can be improved and the increase in viscosity can be suppressed in a high-temperature environment, and when the content is 3.0% by mass or less, the curability can be improved.

In addition, it is preferable that the ink with low curability contains a polymerization inhibitor, and the ink with high curability does not substantially contain a polymerization inhibitor. Thereby, a difference in curability can be provided between the inks. The fact that the ink does not substantially contain a polymerization inhibitor means that the polymerization inhibitor is not actively used as a material during the production of the ink, or that the content of the polymerization inhibitor in the ink is known and is determined using a method of common general technical knowledge. It means that it is below the detection limit.

-Pigments-
As the pigment, inorganic pigments or organic pigments can be used. For example, black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, glossy color pigments such as gold and silver can be used. One of the above pigments may be used alone, or two or more thereof may be used in combination. However, when clear ink is used, it does not contain coloring materials such as pigments.

Examples of inorganic pigments that can be used include carbon black (CI Pigment Black 7) such as furnace black, lamp black, acetylene black, and channel black, iron oxide, and titanium oxide.

Organic pigments include azo pigments such as 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, quinophthalone pigments, and the like. polycyclic pigments, dye chelates (e.g. basic dye chelates, acid dye chelates, etc.), dye lakes (basic dye lakes, acid dye lakes), nitro pigments, nitroso pigments, aniline black, daylight Fluorescent pigments may be mentioned.

When the above pigments are used, their average particle size is preferably 300 nm or less, more preferably 50 to 250 nm. When the average particle size is within the above range, the reliability of ink ejection stability and dispersion stability is further improved, and an image with excellent image quality can be formed. In addition, an average particle diameter is measured by a dynamic-light-scattering method.

- Dispersant -
When the ink contains a pigment, a dispersant may be used to improve pigment dispersibility.

As the dispersant, a polymer dispersant is preferable, and examples thereof include polyoxyalkylenepolyalkylenepolyamines, vinyl-based polymers and copolymers, acrylic-based polymers and copolymers, polyesters, polyamides, polyimides, polyurethanes, and amino-based polymers. Among these, acrylic polymers and copolymers are preferable, and acrylic block copolymers having an acid value of 5 mgKOH/g or more and an amine value of 10 mgKOH/g or more are more preferable from the viewpoint of adsorption to pigments.

Commercially available products include, for example, the Ajinomoto Fine-Techno Co., Inc. Ajisper series, and the Solspers series (trade name: Solsperse 32000 (acid value: 15.5 mgKOH/g, acid value: 15.5 mgKOH/g, Amine value: 31.2 mgKOH/g), trade name: Solsperse 39000 (acid value: 33 mgKOH/g, amine value: 0 mgKOH/g), etc.), DISPERBYK series manufactured by BYK Chemie Japan Co., Ltd. ((trade name: DISPERBYK-168 , acid value: 0 mgKOH / g, amine value: 11 mgKOH / g), (trade name: DISPERBYK-167, acid value: 0 mgKOH / g, amine value: 13 mgKOH / g), etc.), BYKJET series, manufactured by Kusumoto Kasei Co., Ltd. Examples include the Disparon series.

-Other ingredients-
Other components include, but are not particularly limited to, conventionally known organic solvents, slip agents (surfactants), penetration enhancers, humectants (moisturizing agents), fixing agents, antifungal agents, preservatives, oxidizing agents, Inhibitors, UV absorbers, chelating agents, pH adjusters, thickeners and the like are included.

--Surfactant--
The surfactant is not particularly limited and can be appropriately selected depending on the intended purpose. Examples thereof include higher fatty acid-based surfactants, silicone-based surfactants, fluorine-based surfactants, and the like.
The content of the surfactant is preferably 0.1% by mass or more and 3% by mass or less, more preferably 0.2% by mass or more and 1% by mass or less, relative to the mass of the ink. When the content is 0.1% by mass or more, the wettability can be improved, and when the content is 3% by mass or less, the curability can be improved.

--Organic solvent--
Although the ink may contain an organic solvent, it is preferable not to contain it if possible. By not containing organic solvents (e.g. VOC (volatile organic compounds) free), volatile organic solvents do not remain in the cured film, ensuring the safety of printing sites and preventing environmental pollution. becomes. The term “organic solvent” means what is generally called a volatile organic compound (VOC), and examples thereof include ether, ketone, xylene, ethyl acetate, cyclohexanone, and toluene. It should be distinguished from a monomer. Moreover, "not including" an organic solvent means not including substantially, and the content is preferably less than 0.1% by mass.

- Physical properties of ink -
The static surface tension of the ink at 25° C. is preferably 20 mN/m or more and 40 mN/m or less, more preferably 28 mN/m or more and 35 mN/m or less. Static surface tension can be measured at 25° C. using a static surface tensiometer (CBVP-Z type, manufactured by Kyowa Interface Science Co., Ltd.). The static surface tension assumes specifications of commercially available inkjet ejection heads such as GEN4 manufactured by Ricoh Printing Systems Co., Ltd., for example.

-Ink manufacturing method-
The ink is produced by adding a pigment, a dispersant and a polymerizable compound to a dispersing machine using media such as a ball mill, Kitty mill, disk mill, pin mill, and Dyno mill, and dispersing and kneading to prepare a pigment dispersion. can be obtained by further mixing a polymerization initiator, a polymerization inhibitor, a surfactant, etc. with this. Alternatively, a medialess dispersing device such as a disper or homogenizer may be used.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

<Example of preparation of pigment dispersion>
-Preparation of cyan pigment dispersion-
Phenoxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 39.5 parts by weight, polymer pigment dispersant ("DISPERBYK-168", BYK) 1.5 parts by weight, and cyan pigment ("LIONOL BLUE FG-7330 , manufactured by Toyocolor Co., Ltd.) was added, and the mixture was stirred and mixed with a stirrer for 1 hour, and then stirred with a bead mill for 2 hours to prepare a cyan pigment dispersion. The solid content concentration of the cyan pigment in the obtained cyan pigment dispersion was 18% by mass.

-Preparation of Magenta Pigment Dispersion-
42.2 parts by mass of phenoxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.), 1.8 parts by mass of a polymer pigment dispersant ("DISPERBYK-168", manufactured by BYK), and a magenta pigment ("Cinquasia Pink K4410", 6.0 parts by mass of BASF Corporation) was added, and the mixture was stirred and mixed with a stirrer for 1 hour, and then stirred with a bead mill for 2 hours to prepare a magenta pigment dispersion. The solid content concentration of the magenta pigment in the obtained magenta pigment dispersion was 12% by mass.

-Preparation of yellow pigment dispersion-
Phenoxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 42.5 parts by mass, polymer pigment dispersant ("DISPERBYK-168", BYK) 2.8 parts by mass, and yellow pigment ("Pigment Yellow 155", Clariant Co., Ltd. After adding 6.0 parts by mass of 6.0 parts by mass of the product and stirring and mixing with a stirrer for 1 hour, the mixture was stirred with a bead mill for 2 hours to prepare a yellow pigment dispersion. The solid content concentration of the yellow pigment in the obtained yellow pigment dispersion was 12% by mass.

-Preparation of black pigment dispersion-
37.5 parts by mass of phenoxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.), 3.5 parts by mass of polymeric pigment dispersant ("Solspers 39000", manufactured by Lubrizol), black pigment ("MA11", Mitsubishi Chemical Corporation) (manufactured by the same company) was added, and after stirring and mixing with a stirrer for 1 hour, the mixture was stirred with a bead mill for 2 hours to prepare a black pigment dispersion. The solid content concentration of the black pigment in the obtained black pigment dispersion was 18% by mass.

-Preparation of white pigment dispersion-
29.0 parts by mass of phenoxyethyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.), 0.6 parts by mass of polymeric pigment dispersant ("Solspers 24000 GR" manufactured by Lubrizol), polymeric pigment dispersant ("Ajisper PB881") , Ajinomoto Fine Tech Co., Ltd.) 0.4 parts by mass, titanium oxide ("Titanics JR-301", manufactured by Tayca, silica content 3% by mass, alumina content 1% by mass) 20.0 parts were added. After stirring and mixing with a stirrer for 1 hour, the mixture was stirred with a bead mill for 2 hours to prepare a white pigment dispersion. The solid content concentration of the white pigment in the resulting white pigment dispersion was 40% by mass.

<Example of preparation of ink and ink set>
Each ink was prepared by a conventional method using materials having the formulations shown in Tables 1 to 4 below. Also, an ink set was produced by combining a plurality of inks shown in Tables 1 to 4 below.
The unit of numerical values for various formulations shown in Tables 1 to 4 below is "% by mass". Further, the content of the pigment dispersion shown in Tables 1 to 4 below is indicated as the total amount, not as the solid content.

Details of each material shown in Table 1 below are as follows.

-Polymerizable compound-
・CN963J85 (urethane acrylate oligomer, manufactured by Sartomer)
・ ACMO (acryloyl morpholine, manufactured by KOHJIN Co., Ltd.)
・ IBXA (isobornyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.)
・ PEA (phenoxyethyl acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.)
・CTFA (cyclic trimethylolpropane formal acrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd.)

-Polymerization inhibitor-
・ MEHQ (p-methoxyphenol, manufactured by Tokyo Chemical Industry Co., Ltd.)

-Polymerization initiator-
· 819 (DAIDO UV-CURE 819, phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide, manufactured by Daido Chemical Industry Co., Ltd.)
· APO (DAIDO UV-CURE APO, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, manufactured by Daido Chemical Industry Co., Ltd.)
・ DETX (2,4-diethylthioxanthone, manufactured by Daido Chemical Industry Co., Ltd.)

<Execute printing>
(Ink Examples 1-1 to 5-6, Ink Comparative Examples 1-1 to 1-6)
(Ink Set Examples 1 to 5, Ink Set Comparative Example 1)
An inkjet printer (RICOH Pro TF6250, manufactured by Ricoh Co., Ltd.) was modified so that the first ink and the second ink of the same color were supplied to the inkjet head as shown in FIG. In addition, an electromagnetic valve is provided in an ink supply path connecting the ink-jet head with the ink-jet head and the ink-jet head. The supply of the ink and the second ink can be switched. Further, the ink jet printing apparatus was modified so that the amount of the first ink and the second ink filled in the ink jet head was as shown in the time chart shown in FIG.
Next, the inkjet printer is filled with the first ink and the second ink in the combinations shown in Tables 1 to 4 below, and printing is performed so that the amount of irradiation light is as shown in the time chart shown in FIG. did As the material to be printed, a polycarbonate base material (Mitsubishi Engineering-Plastics Co., Ltd., Iupilon 100FE2000 masking, thickness 100 μm) was used, and a solid image with a thickness of about 12 μm was printed on the material to be printed, and the printing was performed for 1000 sheets. rice field.
The curability of the first ink in the example was lower than that of the second ink, and the curability of the first ink in the comparative example was higher than that of the second ink. Specifically, the integrated amount of light required for curing each ink was as shown in Tables 1 to 4 below.

[Robustness]
The first printed image (the inkjet head is filled with the first ink and ejected to form an image) and the 500th printed image (the inkjet head is filled with the second ink). , and an image formed by ejecting this) were obtained, and the surfaces of these images were rubbed with a cotton swab to visually observe the state of the surfaces, and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: The surface is not scratched B: The surface is not scratched, but is slightly sticky C: The surface is slightly scratched and sticky D: The surface is scratched and part of the image is transferred be done

[Ejection stability in the middle period of printing]
After completing the printing of the 800th sheet (when the inkjet head is filled with the second ink), a nozzle defect measurement chart was printed, and the state of ejection disturbance and ejection failure was evaluated based on the following evaluation criteria. .
(Evaluation criteria)
A: Disturbance or non-discharge is not observed at all B: Disturbance or non-discharge occurs from 1 nozzle or less C: Disturbance or non-discharge occurs from 2 to 29 nozzles D: Disturbance or non-discharge occurs from 30 nozzles or more There is ejection failure

[Ejection stability after rest]
After completing the printing of the 100th sheet (when the inkjet head is filled with the first ink), the inkjet printing apparatus is placed in a resting state for 48 hours, after which a nozzle missing measurement chart is printed to check for ejection disturbance and failure. The ejection state was evaluated based on the following evaluation criteria.
(Evaluation criteria)
A+: No discharge disturbance or discharge failure observed A: Discharge discharge disturbance or discharge failure from 1 to 3 nozzles B: Discharge disturbance or discharge failure from 4 nozzles to 10 nozzles C: 11 nozzles or more 99 D: Disturbance or failure of ejection from 100 nozzles or more

REFERENCE SIGNS LIST 1 delivery section 2 recording medium 3 conveying roller 4 ejection section 4a ejection section 4b ejection section 5 irradiation section 6 winding section 9 solenoid valve 9a solenoid valve 9b solenoid valve 10 ink station 10a ink station 10b ink station 11 containing the first ink Storage portion 11a Storage portion 11b for storing the inks forming the first ink set Storage portion 11b for storing the inks forming the first ink set Storage portion 12 for storing the second ink Portion 12a Storage portion 12b Storage portion storing inks constituting the second ink set 20 Sub-tank 20a Sub-tank 20b Sub-tank 50 Light amount control means 90 Supply control means 91 Job determination unit 92 Solenoid valve control unit 93 Solenoid valve driver

Japanese Patent Publication No. 2010-521330

Claims (7)

a first ink and a second ink that are cured by being irradiated with an active energy ray;
a liquid ejection head for ejecting liquid;
a supply control means for controlling supply of the liquid to the liquid ejection head,
the first ink and the second ink are the same color;
Curability of the first ink is lower than curability of the second ink,
The liquid ejection head at the start of printing is filled with the first ink,
The liquid ejection head is filled with the first ink at the end of printing,
The supply control means starts supply of the second ink to the liquid ejection head after the start of printing, and further controls the supply of the liquid after starting the supply of the second ink and before the end of printing. A liquid ejection apparatus, characterized by starting the supply of the first ink to an ejection head. 2. The liquid ejecting apparatus according to claim 1, wherein the integrated amount of light required for curing the first ink is three times or more the integrated amount of light required for curing the second ink. The liquid ejecting apparatus further includes irradiation means for irradiating the active energy ray, and light amount control means for controlling the irradiation light amount of the active energy ray by the irradiation means,
The light amount control means reduces the irradiation light amount when the supply control means starts supplying the second ink to the liquid ejection head, and reduces the irradiation light amount when the supply control means starts supplying the second ink to the liquid ejection head. 3. The liquid ejecting apparatus according to claim 1, wherein the amount of irradiation light is increased with the start of supply of one ink. the first ink and the second ink are other than white ink or clear ink;
4. The liquid ejecting apparatus according to any one of claims 1 to 3, wherein the first ink contains a polymerization inhibitor, and the second ink does not substantially contain a polymerization inhibitor. The ratio of the mass of the polymerization initiator contained in the first ink to the mass of the first ink is the ratio of the mass of the polymerization initiator contained in the second ink to the mass of the second ink. 5. The liquid ejecting apparatus according to any one of claims 1 to 4, wherein the liquid ejection device is 20% or less. a first ink set and a second ink set each having a plurality of inks that are cured by being irradiated with an active energy ray;
a liquid ejection head for ejecting liquid;
a supply control means for controlling supply of the liquid to the liquid ejection head,
each of the first ink set and the second ink set has at least one corresponding ink of the same color;
When the corresponding inks of the same color in the first ink set and the second ink set are compared, the curability of the ink of the first ink set is higher than that of the ink of the second ink set. lower than curability,
The liquid ejection head at the start of printing is filled with the ink of the first ink set,
The liquid ejection head at the end of printing is filled with the ink of the first ink set,
The supply control means causes the liquid ejection head to start supplying the ink of the second ink set of the same color as the ink of the first ink set filled in the liquid ejection head after printing is started; Furthermore, after starting the supply of the ink of the second ink set and before the end of printing, the ink of the second ink set filled in the liquid ejection head is supplied to the liquid ejection head. A liquid ejection device, characterized in that the supply of the ink of the first ink set of the same color is started. a first ink and a second ink that are cured by being irradiated with an active energy ray;
a liquid ejection head for ejecting liquid, and
the first ink and the second ink are the same color;
Curability of the first ink is lower than curability of the second ink,
The liquid ejection head at the start of printing is filled with the first ink,
The liquid ejection head is filled with the first ink at the end of printing,
The supply of the second ink to the liquid ejection head is started after printing is started, and the second ink is supplied to the liquid ejection head after the supply of the second ink is started and before the end of printing. 1. A liquid ejecting apparatus, characterized in that supply of ink No. 1 is started.

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