JP2017095601A - Color ink, color filter and reflective display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To satisfy needs for achieving 2 elements, suppressing color shade by mixing without absorbing the color ink at a certain degree and closing coloring pixel shape to a square with receiving an ink, in a pixel capable of achieving 2 elements, suppressing color shade by mixing without absorbing a color ink at a certain degree in a pixel and closing coloring pixel shape to the square with receiving the ink.SOLUTION: There is provided the fact achieving 2 elements such as suppressing color shade by mixing without absorbing the color ink at a certain degree and closing coloring pixel shape to a square with receiving an ink in a pixel containing at least one kind of coloring pigment or coloring dye of 0.5 to 10 wt.% based on weight of whole ink, an organic solvent of carbitols of 30 to 75 wt.% and a lactone-based organic solvent of 3 to 30 wt.%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a colored ink, a color filter, and a reflective display device.

  With the spread of electronic information networks, electronic publishing represented by electronic books has come to be performed. As a device for displaying electronic publication and electronic information, a self-luminous type or a backlight type display device is generally used. However, these display devices tend to cause fatigue when used for a long time for ergonomic reasons, compared to a medium printed on paper. In addition, since the power consumption is large, the display time is limited in the case of battery driving.

  In response to these drawbacks, a reflective display device typified by electronic paper can read characters with a feeling close to that of paper, and can reduce fatigue. In addition, it is suitable for outdoor signage because it can display performance outdoors in the sun and light. In addition, power consumption is small and long-time driving is possible. Since power is not consumed except for screen rewriting, it is also actively used for applications such as electronic signage and electronic price tags, and reflective display devices are being actively developed.

  In reflective display devices typified by electronic paper, black-and-white display is sufficient as long as it is text information only for electronic books, but book illustrations, advertisements, signs, displays that enhance the eye-catching effect, images, catalogs, shelves Colored display is an indispensable technique for displaying bills, price tags, instructions, and the like, and needs are increasing with the colorization of display contents. Therefore, the following methods have been proposed as colorization of the reflective display device.

By incorporating a color filter into the reflective display device, the color area that is to be displayed is displayed in white and the color area that is not to be displayed is displayed in black according to the pattern displayed on the monochrome display. It becomes possible. (Patent Document 1)
As a method of incorporating a color filter into a reflective display device, a method of arranging a color filter in accordance with an electrode pattern displayed on a monochrome display has been proposed. (Patent Document 2)

JP 2003-161964 A JP 2003-107234 A JP 2012-252182 A

  In the method described in Patent Document 1, when a color function is given to the reflective display device, the color function can be easily given by combining a color filter.

  By the way, in the case of a color filter for a reflection type display device, unlike a liquid crystal color filter, if a light blocking portion called a black matrix is provided, the extraction efficiency due to light reflection deteriorates, so that it is necessary not to provide a black matrix.

When a color filter without a black matrix is manufactured, it is necessary to accept ink so as not to mix colors. For this purpose, it is necessary to use a known ink receiving technique such as providing a transparent partition instead of the black matrix or providing an ink receiving layer on the substrate to allow the substrate to receive ink.

  In the case where a transparent partition is provided, there arises a problem that the reflectance and the area ratio of the colored pixels are lowered depending on the area of the partition. In addition, when a light-transmitting bank is used, the number of steps for manufacturing the bank is further increased, alignment accuracy for partition wall manufacture is required, and the partition wall thickness is required to be thin.

  Providing the ink receiving layer generally reduces the cost of producing the color filter, and therefore it is common to provide the ink receiving layer. Colored pixels are printed on the ink receiving layer using a printing technique such as an inkjet method or a printing method.

  A method has been proposed in which alignment is not required by performing color printing directly on a reflective display by an inkjet method and eliminating the step of bonding the color filter and the reflective display device main body. Further, the ink jet method is non-contact printing, has less foreign matter, and is plateless printing, and therefore has an advantage that the cost can be reduced as compared with printing using a plate.

  By the way, in a color reflective display device using a color filter system, the area ratio of one color filter arranged on one drive pixel greatly affects the color reproducibility. This area ratio is expressed as “area ratio = area of color filter ÷ area driven by driving pixel”. Since the area ratio is the coloring area in the drive pixel, it is called the in-pixel coloring ratio.

  When the in-pixel coloring rate is low, in order to improve the color reproducibility, it is necessary to increase the density and film thickness of the colored ink, and as a result, the transmittance of the colored ink decreases and the reflectance decreases. By increasing the in-pixel coloring rate, the concentration and thickness of the colored ink can be reduced, and the ink transmittance can be increased.

  That is, by increasing the in-pixel coloring rate, the reflectance and color reproducibility, which are the problems of reflective display devices such as color electronic paper, can be maximized. However, if the pixel size is simply increased, color mixture occurs due to overlapping of pixels. Therefore, in order to increase the in-pixel coloring rate, it is necessary to make the shape of the drive pixel and the shape of the color filter the same. Since the shape of the drive pixel is generally a quadrangle, it is necessary to make the pixel shape close to a quadrangle. Other than that, improvement of coating accuracy and prevention of color mixing are problems. In addition, when there is color shading in the color filter, the color filter looks uneven and color reproducibility is reduced. Therefore, it is desirable that the chromaticity difference of the shading is within ± 10%. If there is a color shading of ± 10% or more, unevenness will be visible to the human eye.

  In order to make the pixel shape close to a square, of course, the ink receiving layer must firmly receive ink droplets from the colored ink. That is, when ink droplets are printed on an unacceptable substrate, the colored ink tends to become circular due to surface tension, so the pixel shape cannot be made square. However, in the case of an ink receiving layer that absorbs all the colored ink droplets, the ink density is doubled at the location where the droplets overlap, and the location where the three locations overlap is tripled. At this time, it is impossible to make the ink density uniform in the colored pixels with one colored pixel, and it becomes impossible to adjust the color tone. In addition, when the distance between the droplets is increased, colored pixels called white spots are missing, and appear as unevenness when forming the color filter. In other words, in one pixel, it is a challenge to achieve both the two factors of suppressing color unevenness by mixing without absorbing colored ink to some extent and accepting ink to make the colored pixel shape close to a square. there were.

The present invention has been made in view of the above problems, and the invention according to claim 1 is characterized in that 0.5 to 10% by weight of at least one coloring pigment or coloring dye based on the total weight of the ink. And 30 to 75% by weight of an organic solvent of carbitols and 3 to 30% by weight of a lactone organic solvent.

  The invention according to claim 2 is the colored ink according to claim 1, characterized in that it contains 0.01 to 3.00% by weight of a fluorosurfactant.

  The invention described in claim 3 comprises, in order, a base material, an ink receiving layer made of urethane resin having a thickness of 4 to 25 μm, and a colored pixel made of colored ink according to claim 1 or 2. It is.

  The invention according to claim 4 is, in order, an ink receiving material comprising a substrate for a display device, an electrode layer, an electrode pattern layer, a microcapsule layer, a light transmission electrode layer, an electrode sheet layer, and a urethane resin having a thickness of 4 to 25 μm. A reflective display device comprising: a layer; a colored pixel made of the colored ink according to claim 1; and a protective layer.

  According to this invention, it is possible to provide a colored ink that can achieve both the color ink receptive performance with respect to the ink receptive layer and the color uniformity performance due to the color ink wetting and spreading within the colored pixels, and an arbitrary pixel shape that can be adjusted in color. Can be formed.

  By reducing the surface tension of the colored ink and changing the color distribution in the colored pixel made of the colored ink, the shape and color of the colored pixel can be adjusted. A color filter having no color unevenness and a high coloring ratio in the colored pixel can be produced. A colored ink having a uniform color in the colored pixels and a high absorption rate to the receiving layer is provided, and a reflective display device capable of achieving both white reflectance and color reproducibility can be manufactured.

1 is a conceptual cross-sectional view of a reflective display device according to the present invention. It is a see-through | perspective perspective view of the inkjet printer concerning manufacture of the color filter of this invention. It is a top view for demonstrating the formation method of a colored pixel of the color filter concerning this invention. It is a top view for description of the shape of a coloring pixel of the color filter concerning the present invention.

  Hereafter, the detailed form of this invention is demonstrated.

  Color filter by adding a color printing process by an inkjet method to the manufacturing process of a conventional monochrome reflection type display device or a combination of a reflection type display device of the present invention, a monochrome reflection type display device which is a reflection type display device main body and a color filter Is incorporated.

  In general, in a reflective display device typified by electronic paper, as a method for manufacturing an electrophoretic display device that is one of the types of electronic paper, for example, an opposing method described in JP-A-1-86116, which has at least one surface of a light transmission type. A reflective display that is an electrophoretic display device that encloses a dispersion system including electrophoretic particles between electrode plates and changes the optical reflection characteristics by a display control voltage applied between the electrodes to perform a required display. A device is listed.

The color filter of the present invention is used in combination with a reflective display device main body. After the color filter is manufactured, a reflective display device main body and a bonded reflective display device are obtained. Alternatively, the color filter layer may be directly formed on the reflective display device. In that case, an ink receiving layer is provided on the electrode layer of the reflective display device, and a color filter is formed by an inkjet method. FIG. 1 is an explanatory diagram of a layer structure of color electronic paper as an example of a reflective display device.

  As the ink receiving layer, for example, an inkjet recording medium described in JP-A-2000-43405 or an inkjet printer recording medium described in JP-A-2008-272972 can be used. In particular, those with high transparency are preferred. However, the ink jet receiving material having a porous structure as described in JP-A-2000-238408 cannot be used as the ink receiving layer of the present invention. This is because, when the ink receiving layer has a porous structure, the colored ink is soaked in the layer, and the uniformity of wetting and spreading is impaired. That is, the ink receiving layer is required to be a film-holding type. As a material for the ink receiving layer, performances such as transparency, no discoloration or discoloration of the received colored ink, and various resistances are required. A urethane resin having the above characteristics is used for the receiving layer of the present invention. As a solvent for the ink receiving layer, an aqueous solvent such as water or IPA or an alcohol solvent, or an organic solvent such as toluene or ethyl acetate that is highly soluble in a urethane resin is used.

  The ink receiving layer is applied so that the material has a thickness of 4 to 10 μm after drying with a coating apparatus, for example. Coating is performed using a die coater, spin coater, bar coater or the like as the coating apparatus. However, the coating method is not limited to these methods. When the thickness is 4 μm or less, the solvent in the ink cannot be absorbed and the wetting spread becomes too large. Or, since the thickness varies, there is a possibility that a portion without the ink receiving layer may appear. When the thickness is large, the distance between the reflective layer such as the electrode pattern layer of the reflective display device and the color filter is increased, so that the light reflected by the reflective layer is diffused. The amount is reduced and the color reproducibility is lowered. After applying the ink receiving layer material, the ink receiving layer is formed by solidifying by a method such as heat, vacuum, or UV irradiation.

  The material of the colored ink in the present invention includes a colorant, a resin, a dispersant, and a solvent. The colorant of the ink may be either a coloring pigment or a coloring dye. It is preferable to use three types of hues of red, green, and blue, but yellow, cyan, purple, magenta, orange, and yellowish green may be used. The combination of colors is not limited, and only two types may be used.

  Specific examples of the coloring pigment used as the colorant include Pigment Red 9, 19, 38, 43, 97, 122, 123, 144, 149, 166, 168, 177, 179, 180, 192, 215, 216, 208. 216, 217, 220, 223, 224, 226, 227, 228, 240, Pigment Blue 15, 15: 6, 16, 22, 29, 60, 64, Pigment Green 7, 36, Pigment Red 20, 24, 86, 81, 83, 93, 108, 109, 110, 117, 125, 137, 138, 139, 147, 148, 153, 154, 166, 168, 185, Pigment Orange 36, Pigment Violet 23, etc. Limited to Not intended to be. Further, these may be used in combination of two or more in order to obtain the desired hue.

  As the resin for the material of the colored ink, casein, gelatin, polyvinyl alcohol, carboxymethyl acetal, polyimide resin, acrylic resin, epoxy resin, melanin resin, etc. are used, which are appropriately selected in relation to the pigment. .

  When heat resistance and light resistance are required, an acrylic resin or an epoxy resin is preferable.

The dispersant for improving the dispersion of the colorant in the resin will be described. As a dispersant
Examples of the nonionic surfactant include polyoxyethylene alkyl ether, and examples of the ionic surfactant include sodium alkylbenzene sulfonate, poly fatty acid salt, fatty acid salt alkyl phosphate, and tetraalkyl ammonium salt. In addition, organic pigment derivatives, polyester and the like can be mentioned.

  One type of dispersant may be used alone, or two or more types of dispersants may be mixed and used.

  As the solvent species used in the colored ink, those having an appropriate surface tension range of 35 mN / m or less in ink jet printing and a boiling point of 130 ° C. or more are preferable. When the surface tension is 35 mN / m or more, the dot shape stability at the time of ink jet discharge is significantly adversely affected. When the boiling point is 130 ° C. or less, the drying property in the vicinity of the nozzle is remarkably increased. This is not preferable because it causes clogging and other defects. The viscosity is preferably adjusted to 5 to 20 cps.

  The inventors have found that the type of solvent used in the colored ink has a great influence on the amount of colored ink absorbed in the ink receiving layer. That is, increasing the ink internal ratio of the solvent that easily melts the ink receiving layer improves the ink receiving performance, and using a solvent that does not melt or does not melt the ink receiving layer decreases the ink receiving performance and reduces Improves wettability.

  Specifically, when an ink receiving layer that is soluble in an aqueous solvent is formed, a solvent that does not melt the receiving layer such as carbitols in the ink and a solvent that easily melts the lactone ink receiving layer are used. In addition, an alcohol solvent that is a solvent that easily melts the ink receiving layer may be added.

  “Easily melted” in this case was defined as dissolving the ink receiving layer within 1 minute when a solvent droplet was dropped on the ink receiving layer having a thickness of 10 μm.

  Further, it was defined that the film hardly remained when the solvent droplet was dropped on the film thickness of 10 μm of the ink receiving layer. By controlling the ratio, it was possible to achieve both ink acceptability and in-pixel color uniformity.

  The carbitols include carbitol solvents such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether, or their cellosolves and acetate compounds of carbitols.

  Gamma butyrolactone was used as a solvent for dissolving the resin of the ink receiving layer. Further, diethylene glycol monoethyl ether acetate and butyl diglycol acetate were used as solvents that hardly melt the receiving layer. The ink composition is dispersion resin 20 (wt%), pigment 2 (wt%), solvent diethylene glycol monoethyl ether acetate 58 (wt%), gamma butyrolactone 10 (wt%), butyl diglycol acetate 10 (wt%). Made.

  When the ratio of the solvent component that does not melt the receiving layer of the ink composition of the colored ink is 30 (wt%) or less and the solvent that easily melts the ink receiving layer is contained in an amount of 30 (wt%) or more, the colored ink The instant ink-receiving layer printed on the ink-receiving layer soaks into the ink-receiving layer, creating a gap between the droplets called white spots. In addition, when the ratio of the solvent component that does not melt the ink receiving layer of the colored ink composition so much is 75 (% by weight) or more and the solvent that easily melts the ink receiving layer is 3 (% by weight) or less, the receiving performance decreases. It becomes a circular shape due to the surface tension of the colored ink. Therefore, it was found that the ink composition ratio in the range of 30 to 75% by weight of an organic solvent of carbitols and 3 to 30% by weight of gamma-butyrolactone is preferable in order for the present invention to exert more effects.

  When a silicone-based or fluorine-based material is added to the ink as a surfactant, the surface tension of the ink decreases and the wetting spread increases. It has been found that this property is used to improve the color uniformity within the colored pixels.

  Examples of surfactants include silicone resins and silicone rubbers that have an organosilicone or alkylfluoro group in the main chain or side chain and contain a siloxane component, as well as vinylidene fluoride, vinyl fluoride, ethylene trifluoride, etc. Alternatively, a fluororesin such as a copolymer thereof can be used.

  A silicone-based or fluorine-based compound is added to a solid content ratio of 0.01 to 3.00 (% by weight). When the addition amount is less than 0.01 (% by weight), the wetting and spreading effect is small. When 3.00 (% by weight) or more is added, the surface tension of the colored ink is too low, and the ejection performance in the ink jet deteriorates. Therefore, when using a surfactant to control the color ink acceptance and uniformity within the colored pixels, the amount of surfactant added should be within the range of 0.01 (wt%) to 3.00 (wt%). Make adjustments.

  For production of a color filter, for example, pattern printing is performed on a transparent substrate by an inkjet method. Alternatively, an arbitrary pattern is printed in accordance with an electrode base material composed of a light-transmitting electrode layer and an electrode sheet layer on which the electrode wiring is patterned. In either case, an ink receiving layer is formed on one side in advance.

  Next, an embodiment of an ink jet apparatus used in the present invention will be described with reference to the drawings.

  FIG. 2 is an explanatory view of an ink jet coating apparatus in the color electronic paper manufacturing method of the present invention. As a device configuration of the coating device, a reflective display device panel 20 is placed, and it is fixed from a transport stage 30 that accurately transports in one direction and a color electronic paper base material (hereinafter simply referred to as a base material) for a reflective display device. An ink jet head unit 60 that has a height and can be moved orthogonally to the transport direction is provided.

  As the ink jet head, a piezoelectric drive type ink jet head was used. A plurality of nozzles for ejecting ink are provided, and these nozzles are arranged in a predetermined direction in the scanning direction in which the inkjet head is scanned relative to a color pixel pattern (hereinafter simply referred to as a pixel pattern) of a color filter. It is arranged so that there is an interval. Furthermore, an inkjet head control panel 11 for controlling ejection of inkjet ink from the nozzles of the inkjet head 10 is provided.

  By setting the distance from the inkjet head nozzle to the substrate to be 300 μm to 2000 μm, it becomes possible to apply with high application accuracy. If the distance is 300 μm or less, the risk of contact between the inkjet head and the substrate is increased, and if it is 2000 μm or more, ejection flight bending (misdirection) is likely to occur. In addition, a maintenance device 12 for recovering the ejection properties of the nozzles of the inkjet head is provided. The maintenance device 12 is provided with a nozzle or the like for wiping the nozzle surface with a waste cloth or a film, and discharging a liquid, and a general inkjet head maintenance mechanism 12 can be used.

In order to determine the position of the pixel pattern of the coated color electronic paper, an alignment camera and an image processing unit are preferably provided. Even when a color filter pattern is printed on a transparent base material, an alignment camera and an image processing unit are provided because the base material requires an alignment mark for bonding to the reflective display device i-panel. preferable.

  In the present invention, the ink jet coating apparatus shown in FIG. 2 was used, an ink jet head having a plurality of nozzles was scanned relative to the pixel pattern, and the ink receiving layer of the base material was provided. Ink jet ink is discharged and supplied to the surface, and a color filter is formed on the ink receiving layer. In the present invention, an ink jet head having a plurality of nozzles is scanned relative to the pixel pattern. As shown in FIG. 2, the substrate side may be scanned or the inkjet head side may be scanned. Moreover, you may operate both a base material and an inkjet head.

  In the pixel shape of the present invention, it is preferable to perform printing with an ink jet ejection arrangement corresponding to the size of the pixel in order to approximate a square shape. That is, it is preferable to produce a higher definition pattern from the relationship between the pixel size, the droplet, and the landing area. FIG. 3 is an explanatory diagram of a pixel shape and a discharge arrangement pattern. The ink droplet landing part 80 is continuously applied to produce a long hole pixel. At that time, when the interval F between the ink droplets is long, the shape becomes concave, and when the interval is short, the central portion is expanded, so that the droplet diameter and interval F are adjusted to It is preferable to make a straight line shape. Further, a predetermined pixel coloring portion 90 is formed by making a shape in which the long hole shapes are arranged side by side by an arbitrary number.

  FIG. 4 is an explanatory diagram of pixels. When the ink composition contains a large amount of solvent that easily dissolves the ink receiving layer, color unevenness is generated in the colored pixels, resulting in a pixel 100 shape. When the ink receiving layer contains a large amount of solvent that is difficult to dissolve, the colored pixels It approaches the ellipse 110. By appropriately melting the ink receiving layer, only the interface between the colored ink and the ink receiving layer is firmly fixed, and the upper portion of the colored ink is wet and spread. By doing so, the fixing of the colored ink to the ink receiving layer and the color uniformity are compatible.

  The colored ink is applied to the ink receiving layer, and then dried and solidified. The drying means and / or the solidifying means are any one of heating, air blowing, decompression, light irradiation, electron beam irradiation, or a combination of two or more thereof.

After the colored ink is dried and solidified, a protective film may be formed to protect the color filter. In order to form a protective film for the color filter, an organic resin such as polyamide, polyimide, polyurethane, polycarbonate, acrylic or silicone, Si ₃ N ₄ , SiO ₂ , SiO, Al ₂ O ₃ , An inorganic film such as Ta ₂ O ₃ can be provided as a protective layer by spin coating, roll coating, printing, or vapor deposition. When the color filter surface is attached to a reflective display and the base material of the color filter also serves as protection of the color filter, of course, the protective film may not be formed.

<Example 1>
As an embodiment, a manufacturing procedure for a reflective display device in which color filters are printed in a matrix will be described.

  A reflective display device using a microcapsule electrophoresis system was manufactured. In this type of display device, positive and negatively charged white and black particles are placed in a microcapsule filled with a transparent solvent, and an image is formed by pulling up each particle to the display surface by applying an external voltage. It is. Since the size of the microcapsule is as small as several tens μm to several hundred μm, when the microcapsule is dispersed in a transparent binder, it can be coated like ink. This ink can draw an image by applying a voltage from the outside.

  Substrate in sequence from base material for display device, electrode layer, electrode pattern layer, in which this electronic ink is coated on a transparent electrode film, which is a transparent resin film on which a transparent electrode is formed, to form an electrode circuit for driving an active matrix When bonded together, a display device panel which is an active matrix display panel can be obtained. Normally, a component in which electronic ink is coated on an electrode sheet layer, which is a transparent resin film on which a transparent electrode layer, which is a transparent electrode, is called a “front plate”, and a substrate on which an electrode circuit for driving an active matrix is formed is referred to as “ It is called the “back plate”.

  An ink receiving layer was provided on the front plate side. As a material for the ink receiving layer, a mixture of urethane resin, toluene, water, and IPA was used, and it was applied with a die coater so as to have a dry thickness of 7 μm to 9 μm.

  It shows about a coloring ink composition. The colored ink composition used for printing was Red resin as dispersion resin 20 (wt%), pigment 2 (wt%), solvent diethylene glycol monoethyl ether acetate 58 (wt%), gamma butyrolactone 10 (wt%), butyldi Glycol acetate 10 (% by weight) was used.

  A grid-like pattern was printed on the ink receiving layer by an inkjet apparatus. As the print pattern, 5 × 5 droplet application was performed so as to fall within a pixel size of 160 μm square. One droplet volume was about 24 pl, and printing was performed so that the distance between the droplets was 38 μm. Thereby, the space | interval of a pixel became 5 micrometers-8 micrometers, and the pixel coloring rate became about 90%.

  Further, the chromaticity (x, y, Y) in the pixel was measured with a 10 μm spot diameter using a spectroscope. The Red chromaticity was x0.431y0.306Y42.1 at the center, and x0.421y0.308Y45.8 at a location near the outer periphery. The difference in color was 0.01 or less, which was a slight result.

  The color filter was thermally dried at 80 degrees for 10 minutes, and then a protective film was laminated to produce color electronic paper as a reflective display device.

<Example 2>
The same reflective display device and ink receiving layer as in Example 1 were used. As the color ink composition, the dispersion resin 20 (wt%), pigment 2 (wt%), solvent diethylene glycol monoethyl ether acetate 18 (wt%), gamma butyrolactone 50 (wt%), butyl diglycol acetate 10 ( % By weight). A grid-like pattern was printed on the ink receiving layer by an inkjet apparatus. As a printing pattern, 3 × 3 droplet application was performed so as to fall within a pixel size of 160 μm square. One droplet amount was about 24 pl, and printing was performed so that the interval between the droplets was 40 μm. In the colored pixels formed with this colored ink, gaps were generated between the droplets called white spots in the pixels. That is, if the proportion of benzyl alcohol in the colored ink composition is too high, pixels with uniform color cannot be formed, and an efficient color filter layer cannot be formed.

DESCRIPTION OF SYMBOLS 1 ... Base material layer for display apparatuses 2 ... Electrode layer 3 ... Electrode pattern layer 4 ... Microcapsule layer 5 ... Light-transmissive electrode layer 6 ... Electrode sheet layer 7 ... Ink receiving layer 8 ... Color filter 9 ... Protective film 10 ... Inkjet Head 11 ... Inkjet head control base 12 ... Inkjet head maintenance mechanism 20 ... Electronic paper substrate 30 ... Conveying stage 40 ... Inkjet coating device 50 ... Drying unit 60 ... Inkjet head unit 70 ... Ink tank 80 ... Ink droplet landing unit 90 ... Pixel coloring part 100 ... Pixel shape (pixel break)
110 ... Pixel shape (elliptical)

Claims (4)

  0.5 to 10% by weight of at least one coloring pigment or coloring dye, 30 to 75% by weight of organic solvent of carbitols, and 3 to 30% by weight of lactone based on the total weight of the ink A colored ink characterized by containing an organic solvent.   2. The colored ink according to claim 1, comprising 0.01 to 3.00% by weight of a fluorosurfactant.   3. A color filter comprising a base material, an ink receiving layer made of a urethane resin having a thickness of 4 to 25 [mu] m, and a colored pixel by the colored ink according to claim 1.   The substrate for a display device, an electrode layer, an electrode pattern layer, a microcapsule layer, a light transmission electrode layer, an electrode sheet layer, and an ink receiving layer made of a urethane resin having a thickness of 4 to 25 µm, respectively. A reflective display device comprising colored pixels made of colored ink and a protective layer.

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