JP7119500B2 - Inkjet recording device - Google Patents

Description

The present invention relates to an inkjet recording apparatus.

An inkjet recording apparatus mainly ejects liquid ink and adheres the ink to a print medium, or dyes the print medium with the ink. The main components of the ink are, for example, water, an organic solvent, a resin or its original oligomer, and a coloring agent such as a dye or a pigment. Print media are not limited to paper, and recently, films, plastics, and the like are also being used. Furthermore, in the inkjet method, non-woven fabrics and fabrics are sometimes used as printing media. Printed products are also used for wallpaper, street advertisements, banners, etc.

Inks have different weather resistances depending on the colorants they contain. Ink with high weather resistance fades less, while ink with low weather resistance fades more. Therefore, in the ink jet method using inks with high weather resistance and inks with low weather resistance, there is a problem that the image quality is unbalanced due to the difference in the degree of fading of each ink over time.

Therefore, for the purpose of suppressing the shift in the hue of the image as much as possible by maintaining the balance of each color while improving the weather resistance of the image recorded by each of the multiple types of ink, weather resistance was developed in the state recorded on the recording medium. a step of recording a plurality of types of inks having different performances on the recording medium; and applying one or more types of weather resistance improving liquids for improving the weather resistance performance to positions of the recording medium on which the plurality of types of inks are recorded. and applying the weather resistance improving liquid to the recording medium according to the weather resistance performance of the plurality of types of inks. (see Patent Document 1).

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ink jet recording apparatus capable of forming an image with excellent gloss uniformity while suppressing the hue shift of the image over time.

Means for solving the above problems are as follows. Namely
The inkjet recording apparatus of the present invention is
a first head that ejects a plurality of inks with different weather resistance onto a recording medium according to image data to form an image on the recording medium;
a second head for covering each dot in the image with each ink of the plurality of inks and ejecting a weather resistance improving liquid containing a resin and an ultraviolet shielding material for improving the weather resistance of each dot; ,
Based on the image data, the second head for each dot in the image is adjusted so that the effect of improving weather resistance by the weather resistance improving liquid is smaller for dots with high weather resistance than for dots with low weather resistance. a control means for controlling the discharge of the weather resistance improving liquid by
characterized by having

According to the present invention, it is possible to provide an ink jet recording apparatus capable of forming an image with excellent gloss uniformity while suppressing the hue shift of the image over time.

FIG. 1 is a schematic configuration diagram of an inkjet recording apparatus according to one embodiment. FIG. 2 is a block diagram showing the functional configuration of the inkjet printing apparatus. FIG. 3A is a schematic diagram for explaining the first aspect (No. 1). FIG. 3B is a schematic diagram for explaining the first mode (No. 2). FIG. 4A is a schematic diagram for explaining the second aspect (No. 1). FIG. 4B is a schematic diagram for explaining the second aspect (No. 2).

(Inkjet recording apparatus and inkjet recording method)
The inkjet recording apparatus of the present invention has at least a first head, a second head, and control means, and further has other means as necessary.
An inkjet recording method according to the present invention is performed by the inkjet recording apparatus, includes a control step, and further includes other steps as necessary.

In the image recording method disclosed in Japanese Patent Laid-Open No. 2008-149615, a step of recording a plurality of types of inks having different weather resistance performances on the recording medium in a state of being recorded on the recording medium; and applying one or more types of weather resistance improving liquid to the position of the recording medium on which the plurality of types of ink are recorded, and in the applying step, depending on the weather resistance performance of the plurality of types of ink The manner in which the weather resistance improving liquid is applied to the recording medium is varied. In this proposed technique, the weather resistance improving liquid is not applied to all ink dots. In other words, the weather resistance improving liquid is not applied to the dots of the ink having excellent weather resistance. In this case, while the glossiness of the ink dots to which the weather resistance improvement liquid is applied increases, the glossiness of the dots to which the weather resistance improvement liquid is not applied does not increase. is likely to occur.

Therefore, the present inventors have found that when the weather resistance improving liquid is ejected according to the weather resistance of each dot, the weather resistance of the dots with high weather resistance is better than that of the dots with low weather resistance. By applying the weather resistance improving liquid even to dots with high weather resistance while controlling the improvement effect to be small, it is possible to suppress the hue shift of the image over time and further improve the gloss uniformity of the image. We found that it is possible to form it, and have completed the present invention.

<First head>
The first head is a head that ejects a plurality of inks with different weather resistance onto a recording medium according to image data.
The first head is a head for forming an image on the recording medium.

<Second head>
The second head is a head that covers each dot in the image with each ink of the plurality of inks and ejects a weather resistance improving liquid for improving the weather resistance of each dot.
The weather resistance improving liquid contains, for example, at least a resin and an ultraviolet shielding material, and further contains an organic solvent, water, and the like, if necessary.
The resin is not particularly limited and can be appropriately selected depending on the purpose.
The ultraviolet shielding material is not particularly limited and can be appropriately selected according to the purpose. Oxide microparticles are preferred, and titanium oxide microparticles are more preferred.
The primary average particle size of the titanium oxide fine particles is not particularly limited and can be appropriately selected according to the purpose, but is preferably 5 nm to 100 nm.

The mass ratio of the resin and the ultraviolet shielding material (resin:ultraviolet shielding material) in the weather resistance improving liquid is not particularly limited and can be appropriately selected depending on the purpose. 1 is preferred.

The weather resistance improving liquid is preferably colorless and transparent in that it does not change the hue of the image.

<Control means and control process>
As the control means, based on the image data, each dot in the image is controlled so that the weather resistance improvement effect of the weather resistance improving liquid is smaller for dots with high weather resistance than for dots with low weather resistance. , and any means for controlling the ejection of the weather resistance improving liquid by the second head can be appropriately selected according to the purpose without any particular limitation.
In the control step, based on the image data, each dot in the image is controlled so that the weather resistance improving effect of the weather resistance improving liquid is smaller for dots with high weather resistance than for dots with low weather resistance. , there is no particular limitation as long as it is a step of controlling the ejection of the weather resistance improving liquid by the second head, and it can be appropriately selected according to the purpose.

In the inkjet recording apparatus, the weather resistance improving liquid is one type, and the control by the control means or the control step in the discharge of the weather resistance improving liquid by the second head is performed on dots with low weather resistance. It is preferable that the film of the weather resistance improving liquid formed on the dots having high weather resistance is thinner than the film of the weather resistance improving liquid formed. By doing so, the usage amount of the weather resistance improving liquid can be suppressed.

In the inkjet recording apparatus, there are a plurality of types with different weather resistance improvement effects,
The control by the control means or the control step in the ejection of the weather resistance improving liquid by the second head has higher weather resistance than the weather resistance improving effect of the weather resistance improving liquid imparted on dots with low weather resistance. It is preferable to carry out so that the weather resistance improving effect of the weather resistance improving liquid formed on the dots is reduced. Furthermore, it is preferable that the plurality of types of weather resistance improving liquids having different weather resistance improving effects have different weather resistance improving effects depending on the content of the ultraviolet shielding material. By doing so, the uniformity of the thickness of the film formed by the weather resistance improving liquid is improved over the entire image. As a result, the gloss uniformity of the image is better.

Here, an example for confirming the effects of the present invention will be described.
Table 1 below shows an example of the weather resistance improving liquid. The weather resistance improving liquids A to D contain a resin, an ultraviolet shielding material, an organic solvent, and water. The resin content is 5 to 20% by mass, and the ultraviolet shielding material content is 5% by mass. Liquid E is a liquid (overcoat liquid) that does not contain an ultraviolet shielding material.

Titanium oxides (TTO-55, TTO-51, TTO-S, TTO-V) in Table 1 are microparticles of titanium oxide manufactured by Ishihara Sangyo Co., Ltd., and have an ultraviolet shielding effect.
Emulgen LS-106 is a higher alcohol-based ether-type nonionic surfactant manufactured by Kao Chemical Co., Ltd.
Proxel LV is a preservative manufactured by Avecia.

Table 2 shows the results of subjecting each liquid in Table 1 to the following weather resistance test.
Each liquid shown in Table 1 was applied to a yellow solid image in a coating amount to give a film thickness of 10 μm to obtain a test sample.
Accelerated weather resistance (xenon lamp method) JIS K5600-7-7:2008 fading test specified in JIS was performed on the specimen. Using a super xenon weather meter SX75, the densities of the image after exposure to the xenon lamp for 500 hours (equivalent to outdoor exposure for 1 year) and the original image were measured to determine the color difference ΔE and evaluated according to the following criteria.
〔Evaluation criteria〕
○: ΔE is less than 25 ×: ΔE is 25 or more

The weather resistance improving liquid containing the ultraviolet shielding material had a good weather resistance improving effect.

Table 3 shows the weather resistance of common inks. In Table 3, 100% gradation indicates a solid image, and 40% gradation indicates that the amount of ink is 40% by mass with respect to the solid image.
The results in Table 3 are obtained by converting the results of the accelerated weather resistance test (the aforementioned xenon lamp method: JIS K5600-7-7:2008) into elapsed years.

The numerical values in Table 3 represent the color difference (ΔE) from 0 years (initial).
"3C" stands for Composite Black, a mixture of Cyan, Magenta, and Yellow.

Next, Tables 4-1 and 4-2 show weather resistance evaluation results when overcoating weather resistance improving liquid A with a certain thickness on some of the inks in Table 3 (equivalent to 3 years) ). The evaluation was performed in the same manner as the weather resistance evaluation of the ink in Table 3.
In Tables 4-1 and 4-2, a color difference (ΔE) of less than 25 was indicated as "◯", and a color difference (ΔE) of 25 or more was indicated as "x".

As can be seen from Table 3, the weather resistance and the degree of fading differ depending on the type of ink. Furthermore, as can be seen from Tables 4-1 and 4-2, when the film thickness of the weather resistance improving liquid is thin, the degree of fading of the ink differs even if the film thickness is the same. Therefore, when one type of weather resistance improving liquid is uniformly applied on an image, the degree of fading of the dots due to each color of ink is different, resulting in non-uniform fading of the image. variation increases. If the thickness of the weather resistance improving liquid is increased (for example, 10 μm), the degree of discoloration decreases for each color, but the weather resistance improving liquid is used excessively, which is not economical.

Therefore, in the present invention, based on the image data, each dot in the image is subjected to a second step so that the weather resistance improving effect of the weather resistance improving liquid is smaller for dots with high weather resistance than for dots with low weather resistance. By controlling the ejection of the weather resistance improving liquid by the two heads, it is possible to equalize the degree of fading of each color of the image and suppress the change in the hue of the image over time.

Exemplary embodiments of an inkjet recording apparatus and an inkjet recording method will be described in detail below with reference to the accompanying drawings. In addition, this invention is not limited by embodiment described below.

FIG. 1 is a schematic configuration diagram of an inkjet recording apparatus 100 according to one embodiment. As shown in FIG. 1, an inkjet recording apparatus (image forming apparatus) 100 mainly includes a sheet conveying section 2 and an image forming section 3, and forms an image on a sheet P which is a recording medium.

The paper transport unit 2 includes a paper feed roller 21, a paper feed side transport roller pair 22, a plurality of transport rollers 23, a paper discharge side transport roller 24, a winding roller 25, and the like.

The paper feed roller 21 rotatably supports a bundle of roll paper around which a predetermined length of paper P is wound. The leading edge of the paper P is inserted between the rollers of the paper feed side transport roller pair 22 arranged near the paper feed roller 21 .

The feed-side transport roller pair 22 is rotationally driven by a drive motor to feed the paper P in the transport direction indicated by the arrow in FIG. 1 (direction from right to left in FIG. 1). As for the transport rollers 23 , a plurality of rollers are arranged horizontally in the direction in which the paper P is transported. The transport roller 23 transports the paper P fed from the paper feeding side transport roller pair 22 in the transport direction while maintaining a horizontal state.

The paper discharge side transport roller 24 guides the paper P transported by the transport roller 23 to the take-up roller 25 . The take-up roller 25 is rotationally driven by a drive motor, and takes up the paper P sent out from the paper feed roller 21 .

In the above description, a configuration example in which roll paper as a recording medium is stretched between the feed roller 21 and the take-up roller 25 has been described, but the embodiment is not limited to this. As another configuration example, instead of the paper feeding roller 21 and the winding roller 25, two rollers around which an endless conveying belt is stretched may be provided. Then, the inkjet recording apparatus 100 may transport the cut paper on the transport belt by rotationally driving the roller pair by the drive motor and transporting the transport belt in the transport direction shown in FIG.

The image forming section 3 mainly includes a colored line head unit 31 and an overcoat line head unit 32 for ejecting a weather resistance improving liquid.

In the colored line head unit 31, line head units 31Bk, 31C, 31M, and 31Y of respective colors of black (Bk), cyan (C), magenta (M), and yellow (Y) are sequentially arranged in the transport direction. there is A plurality of ink discharge nozzles of each color are arranged in the main scanning direction on the paper P side surface of each of the line head units 31Bk, 31C, 31M, and 31Y. Each ink ejection nozzle ejects ink of each color toward the paper P being transported by the transport roller 23 .

The line head units 31Bk, 31C, 31M, and 31Y of each color are synchronized with the transport of the paper P by the paper transport section 2, and eject the ink of the corresponding color sequentially overlapping the same dots. Thereby, the inkjet recording apparatus 100 forms a dot image of a color corresponding to the image data.

Colorants such as pigments dissolved in solvents are mainly used for the inks of the respective colors discharged from the line head units 31Bk, 31C, 31M, and 31Y of the respective colors. Incidentally, the configuration of the ink is not limited to such a configuration, and for example, a dye may be used as a coloring agent.

As described above, the colored line head units 31 have the line head units 31Bk, 31C, 31M, 31Bk, 31C, 31M, and 31Bk, 31C, 31M, and 31M for each of black (Bk), cyan (C), magenta (M), and yellow (Y). It is not limited to 31Y. For example, the inkjet recording apparatus 100 may include, as the colored line head unit 31, a line head unit that ejects light colors such as light gray, light cyan, and light magenta, or other special colors. Also, the order in which the line head units 31Bk, 31C, 31M, and 31Y are arranged in the transport direction is not limited to the above order.

The inkjet recording apparatus 100 includes an overcoat line head unit 32 on the downstream side in the transport direction at a predetermined distance from the line head unit 31Y provided on the most downstream side of the colored line head units 31 .

A plurality of ejection nozzles are provided in the main scanning direction on the surface of the overcoat line head unit 32 on the paper P side. Each ejection nozzle ejects the weather resistance improving liquid toward the paper P being transported by the transport rollers 23 and the discharge-side transport rollers 24 .

The driving method of the line head units 31Bk, 31C, 31M, 31Y and the overcoat line head unit 32 for each color is not particularly limited, and various driving methods may be used as appropriate. For example, as a driving method, a piezoelectric method using a piezoelectric element such as PZT (lead zirconate titanate), a thermal energy method using thermal energy, or the like can be used. Alternatively, as a driving method, an on-demand type head using an actuator such as an electrostatic type using electrostatic force, a continuous ejection type charge control head, or the like can be used.

Next, the functional configuration of the inkjet recording apparatus 100 will be described.

FIG. 2 is a block diagram showing the functional configuration of the inkjet recording apparatus 100. As shown in FIG. The inkjet recording apparatus 100 includes a main controller 101, a colored ink head controller 102, an overcoat head controller 103, a colored line head unit 31 (see also FIG. 1), and an overcoat line head unit 32 (see also FIG. 1). I have.

The colored line head unit 31 functions as a first head that ejects colored ink onto a recording medium according to image data to form an image on the recording medium. The overcoat line head unit 32 functions as a second head that ejects a weather resistance improving liquid to form a film having a weather resistance improvement effect on the image produced by the colored line head unit 31 .

In addition, the inkjet recording apparatus 100 includes a transport drive section, a communication section, and the like, in addition to the above sections. The inkjet recording apparatus 100 also includes an environment detection sensor that detects environmental conditions around the inkjet recording apparatus 100, particularly at least one of temperature and humidity. A temperature sensor, a humidity sensor, or the like, for example, is used as the environment detection sensor.

The main control unit 101 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory). The main control unit 101 also includes an ASIC (Application Specific Integrated Circuit), a communication I/F (interface), and the like. The ROM stores a basic program for the inkjet recording apparatus 100 and a program for executing overcoat liquid ejection control processing. The CPU develops various programs stored in the ROM on the RAM and executes them, thereby controlling the operation of each section of the inkjet recording apparatus 100 .

Under the control of the CPU, the main control unit 101 communicates with a host device such as an external computer via a communication I/F to receive image forming information such as image data (print job, etc.). In addition, under the control of the CPU, the main control unit 101 performs image processing necessary for image formation on the image data received from the host device by the ASIC. Further, the main control unit 101 performs image processing on the received image data, determines the ink ejection amount and ejection timing of each color, and outputs them to the colored ink head control unit 102 as colored head driving data. The colored ink head controller 102 to which the colored head driving data is input drives the colored line head unit 31 according to the colored head driving data to form a desired image on the recording medium.

Further, based on the image data, the main control unit 101 determines that among the dots of each color ink, the weather resistance improving effect of the weather resistance improving liquid is smaller for the dots with high weather resistance than for the dots with low weather resistance. Overcoat head drive data for driving the overcoat line head unit 32 is created so that the overcoat head drive data is output to the overcoat head controller 103 . The overcoat head controller 103 to which the overcoat head drive data is input drives the overcoat line head unit 32 according to the overcoat head drive data. Then, the overcoat line head unit 32 ejects the weather resistance improving liquid so that the weather resistance improving effect of the weather resistance improving liquid is smaller for dots with high weather resistance than for dots with low weather resistance.

Further specific examples of the inkjet recording apparatus and the inkjet recording method of the present invention are described below.

<First Aspect>
In the following aspect, the weather resistance improving liquid is one type, and the weather resistance improving liquid formed on the dots having low weather resistance is controlled by the control means or the control process in the discharge of the weather resistance improving liquid by the second head. This is a mode (first mode) that is carried out so that the coating of the weather resistance improving liquid formed on the dots having high weather resistance is thinner than the coating of the weather resistance improving liquid.

For example, four colors of black (Bk), cyan (C), magenta (M), and yellow (Y) are used as inks. The weather resistance of each ink and the dots produced by each ink can be determined in advance by a weather resistance test of a solid image or the like. Then, the weather resistance of the four color inks is quantified as a weather resistance index, for example, as shown in Table 5 below. Also, the thickness of the film formed by the weather resistance improving liquid according to the weather resistance of the ink is quantified as a film thickness index as shown in Table 5 below. Here, the higher the weather resistance index, the higher the weather resistance. The larger the coating thickness index, the thicker the coating.

The inkjet recording apparatus of the first aspect is prepared with a data table as shown in Table 5 in advance.
The data table in Table 5 is created so that the coating of the weather resistance improving liquid formed on the dots with high weather resistance is thinner than the coating of the weather resistance improving liquid formed on the dots with low weather resistance. It is

Then, the colored line head unit 31 is driven according to the colored head drive data created based on the image data, and after a desired image is formed, the overcoat line head unit 32 is controlled by the main control section 101 as shown in Table 5. According to the over auto head drive data created by referring to the data table, the weather resistance improving liquid formed on the dots with high weather resistance is better than the coating with the weather resistance improving liquid formed on the dots with low weather resistance. The weather resistance improving liquid is discharged so that the film becomes thinner.

Specifically, as shown in FIGS. 3A and 3B, a coating 2 is formed by applying a weather resistance improving liquid so as to cover each of the dots 1Bk, 1C, 1M, and 1Y on the recording medium P. At that time, the thicker the film 2 is formed, the lower the weather resistance of the dot. The thicker the coating 2, the higher the effect of improving the weather resistance. By doing so, the weather resistance of each dot including the film is made uniform, and the change in the hue of the image over time is suppressed. In addition, since the coating 2 is formed on all dots, gloss uniformity is also excellent compared to the case where there are dots on which the coating 2 is not formed.
In the case where a plurality of dots partially overlap, for example, the weather resistance improving liquid is also applied to each dot corresponding to each dot, so that the plurality of droplets of the weather resistance improving liquid overlap. A continuous coating may be formed.
Also, in FIG. 3B, the dots 1Bk, 1C, 1M, and 1Y are formed on the recording medium P, but the dots may soak into the recording medium P as well. Also, the recording medium P may be pretreated with a pretreatment liquid before each ink is applied.

<Second Aspect>
In the following mode, the weather resistance improving liquid is a plurality of types with different weather resistance improving effects, and the control by the control means or the control process in the discharge of the weather resistance improving liquid by the second head forms dots with low weather resistance. A mode in which the weather resistance improvement effect of the weather resistance improvement liquid formed on the dots having high weather resistance is lower than the weather resistance improvement effect of the weather resistance improvement liquid formed on the dots (second embodiment) is.

For example, four colors of black (Bk), cyan (C), magenta (M), and yellow (Y) are used as inks. The weather resistance of each ink and the dots produced by each ink can be determined in advance by a weather resistance test of a solid image or the like. Then, the weather resistance of the four color inks is quantified as a weather resistance index, for example, as shown in Table 6 below. In addition, four types of weather resistance improving liquids having different weather resistance improving effects are prepared according to the weather resistance of the four color inks. The degree of weather resistance improvement of the four types of weather resistance improvement liquids may also be quantified as a weather resistance improvement index, as shown in Table 6 below. Here, the larger the weather resistance index, the higher the weather resistance. As for the weather resistance improvement index, the larger the number, the higher the weather resistance improvement effect. The weather resistance improving effect of the weather resistance improving liquid can be adjusted, for example, by the amount of the ultraviolet shielding material contained.

The inkjet recording apparatus of the second aspect is prepared with a data table as shown in Table 6 in advance.
The data table in Table 6 shows the weather resistance improvement effect of the weather resistance improving liquid formed on the dots with high weather resistance rather than the effect of improving the weather resistance of the weather resistance improving liquid formed on the dots with low weather resistance. is designed to be low.

Then, the colored line head unit 31 is driven according to the colored head drive data created based on the image data, and after a desired image is formed, the overcoat line head unit 32 causes the main control section 101 to According to the overcoat head driving data created by referring to the data table, the weather resistance that is formed on dots with high weather resistance is more effective than the effect of improving weather resistance that is formed on dots with low weather resistance. The weather resistance improving liquid is discharged so that the weather resistance improving effect of the property improving liquid is reduced.

Specifically, as shown in FIGS. 4A and 4B, the weather resistance improving liquids I, II, III, and IV are applied so as to cover the dots 1Bk, 1C, 1M, and 1Y on the recording medium P, respectively. , coatings Ia, IIa, IIIa, IVa of approximately the same thickness are formed. By doing so, the weather resistance of each dot including the film is made uniform, and the change in the hue of the image over time is suppressed. In addition, since the film is formed on all dots, gloss uniformity is also excellent compared to the case where there are dots on which the film is not formed. Furthermore, since the thickness of the coating is about the same, the uniformity of gloss is even better.
In this embodiment, four types of weather resistance improving liquids are used for the four color inks, but if the ink set contains inks with similar weather resistance, Alternatively, two or three types of weather resistance improving liquid may be used, and one type of weather resistance improving liquid may correspond to two or more colors of ink.

Aspects of the present invention are, for example, as follows.
<1> a first head that ejects a plurality of inks with different weather resistance onto a recording medium according to image data to form an image on the recording medium;
a second head for covering each dot in the image with each ink of the plurality of inks and ejecting a weather resistance improving liquid containing a resin and an ultraviolet shielding material for improving the weather resistance of each dot; ,
Based on the image data, the second head for each dot in the image is adjusted so that the effect of improving weather resistance by the weather resistance improving liquid is smaller for dots with high weather resistance than for dots with low weather resistance. a control means for controlling the discharge of the weather resistance improving liquid by
An inkjet recording apparatus characterized by having
<2> The weather resistance improving liquid is one kind,
The control by the control means in the ejection of the weather resistance improving liquid by the second head is formed on the dots with higher weather resistance than the coating of the weather resistance improving liquid formed on the dots with low weather resistance. The inkjet recording apparatus according to <1>, wherein the coating of the weather resistance improving liquid is thinner.
<3> The weather resistance improving liquid is a plurality of types with different weather resistance improving effects,
The control by the control means in the ejection of the weather resistance improving liquid by the second head is formed on dots with high weather resistance rather than the weather resistance improving effect of the weather resistance improving liquid applied on dots with low weather resistance. The inkjet recording apparatus according to <1>, wherein the weather resistance improving effect of the weather resistance improving liquid is reduced.
<4> The inkjet recording apparatus according to <3>, wherein the plurality of types of weather resistance improving liquids having different weather resistance improving effects have different weather resistance improving effects depending on the content of the ultraviolet shielding material.
<5> The inkjet recording apparatus according to any one of <1> to <4>, wherein the weather resistance improving liquid is colorless and transparent.
<6> The inkjet recording apparatus according to any one of <1> to <5>, wherein the ultraviolet shielding material is metal oxide fine particles.
<7> An inkjet recording method executed by an inkjet recording apparatus,
The inkjet recording apparatus includes a first head that ejects a plurality of inks having different weather resistance onto a recording medium according to image data to form an image on the recording medium; a second head that coats each dot in the image and ejects a weather resistance improving liquid containing a resin and an ultraviolet shielding material for improving the weather resistance of each dot;
Based on the image data, the second head for each dot in the image is adjusted so that the effect of improving weather resistance by the weather resistance improving liquid is smaller for dots with high weather resistance than for dots with low weather resistance. and a control step of controlling ejection of the weather resistance improving liquid by means of.

1Bk dot 1C dot 1Y dot 1M dot 2 coating 31 colored line head unit 32 overcoat line head unit 100 inkjet recording device 101 main controller 102 colored ink head controller 103 overcoat head controller P recording medium

JP 2008-149615 A

Claims (6)

a first head that ejects a plurality of inks with different weather resistance onto a recording medium according to image data to form an image on the recording medium;
A weather resistance improving liquid containing a resin and an ultraviolet shielding material for covering each dot in the image formed by each of the plurality of inks to improve the weather resistance of each dot is applied on all of the dots. a second head that ejects to
Based on the image data, the second head for each dot in the image is adjusted so that the effect of improving weather resistance by the weather resistance improving liquid is smaller for dots with high weather resistance than for dots with low weather resistance. a control means for controlling the discharge of the weather resistance improving liquid by
An inkjet recording apparatus comprising: The weather resistance improving liquid is one kind,
The control by the control means in the discharge of the weather resistance improving liquid by the second head is formed on the dots with higher weather resistance than the coating of the weather resistance improving liquid formed on the dots with low weather resistance. 2. The inkjet recording apparatus according to claim 1, wherein the coating of said weather resistance improving liquid is thinner. The weather resistance improving liquid is a plurality of types with different weather resistance improving effects,
The control by the control means in the ejection of the weather resistance improving liquid by the second head is formed on dots with high weather resistance rather than the weather resistance improving effect of the weather resistance improving liquid applied on dots with low weather resistance. 2. The ink jet recording apparatus according to claim 1, wherein the weather resistance improving effect of the weather resistance improving liquid is lowered. 4. The inkjet recording apparatus according to claim 3, wherein the plurality of types of weather resistance improving liquids having different weather resistance improving effects have different weather resistance improving effects depending on the content of the ultraviolet shielding material. 5. The inkjet recording apparatus according to any one of claims 1 to 4, wherein the weather resistance improving liquid is colorless and transparent. 6. The inkjet recording apparatus according to any one of claims 1 to 5, wherein the ultraviolet shielding material is metal oxide fine particles.

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