JPH0460031B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording material suitably used in an inkjet recording method, and particularly to a recording material that has excellent translucency and provides clear images without ink transfer even immediately after recording. The inkjet recording method uses various ink (recording liquid) ejection methods (for example, an electrostatic suction method, a method that applies mechanical vibration or displacement to the recording liquid using a piezoelectric element, a method that uses a piezoelectric element to apply mechanical vibration or displacement to the recording liquid, and a method that heats the recording liquid and causes it to foam and then increases its pressure. Depending on the method used, etc., small droplets of ink are generated and flown, and some or all of them adhere to the recording surface such as paper to perform recording, but it generates less noise. It is attracting attention as a recording method that allows high-speed printing and multicolor printing. Water-based inks are mainly used for inkjet recording in view of safety and printability. This ink is generally prepared from a recording agent such as a dye and a liquid medium. The recording material used in this inkjet recording method has conventionally been ordinary paper or a recording material consisting of a base material called inkjet recording paper on which a porous ink absorption layer is provided. It has been mainly used for surface image observation. As a recording material for such inkjet recording, 1. The ink is quickly absorbed into the recording material, and even when ink dots of different colors overlap,
Ink deposited later should not mix with previously deposited ink, disturb the ink dot, or flow out; 2. Ink droplets should not spread on the recording material and the diameter of the ink dot should not become larger than necessary. , 3. The shape of the ink dot should be close to a perfect circle, and its circumference should be smooth. 4. The ink dot should have a high density and the ink components should have excellent coloring properties. In this way, images recorded by the inkjet recording method are used for surface image observation, but as the performance of inkjet recording devices improves and becomes more widespread, there is a growing demand for recording materials suitable for uses other than surface image observation. be. Applications of recording materials other than surface image observation include those used for observation by projecting the recorded image onto a screen using an optical device such as a slide or OHP (overhead projector), and creating a positive plate for color printing. Examples include CMC (color mosaic filter) used in color separation plates and color displays such as liquid crystals. When the recording material is used for surface image observation, the diffused light of the recorded image is mainly observed, but in the recording material used in these applications, the transmitted light of the recorded image is mainly observed. It becomes a problem. Therefore, excellent light transmittance, particularly in-line transmittance, is required in addition to the above-mentioned performance requirements for recording materials for general inkjet recording. However, the reality is that there is still no known recording material that satisfies all of these required performances. When conventionally known translucent films are used as recording materials, the recorded images lack stability, and the ink may transfer when stacked on paper, the images may be lost, or the clarity of the images may deteriorate during long-term storage. It often decreased. In particular, the drying and fixing properties of the image immediately after recording are poor, and if the image comes into contact with your hands or clothes, the ink will adhere to your hands or clothes and transfer to them, and the recorded image will be damaged. It could not be used immediately for its intended purpose. The cause of this is that when the recorded image is dried and fixed, components of the ink other than the recording agent and other components necessary for the recording area on the recording material, such as components in the liquid medium that are difficult to volatilize, remain near the recording area. As a result, efficient drying and fixing of the recording section may be hindered. The present invention was developed in view of the above points, and can be used in optical equipment such as slides, OHPs, and contact printers, and satisfies various requirements as a recording material for inkjet recording as described above. The object of the present invention is to provide a recording material suitable for inkjet recording, which has particularly excellent ink fixing stability, does not cause ink transfer even immediately after recording, and does not damage images even if it comes into contact with other substances. shall be. That is, the recording material for inkjet recording of the present invention has a recording surface having a plurality of areas of several hundreds of μm x several hundred μm, separated by partitions protruding from the recording surface, and a straight line transmission. It is characterized by a ratio of 2% or more. Further, the inkjet recording method of the present invention is characterized in that recording is performed by applying ink droplets to the recording surface of the recording material for inkjet recording. The recording material of the present invention is a translucent recording material consisting of a single layer having a recording surface provided with a convex portion protruding from the recording surface of the recording material, or a translucent base material and the base material. The recording material has a multilayer structure and has a recording layer provided thereon, and the recording layer has a recording surface provided with the convex portion. Note that the recording surface referred to here is the surface of the recording material on which recording is performed. As the material that can constitute the recording surface of the recording material of the present invention, a material that itself has sufficient translucency, or a material that can become translucent after forming the recording surface is used. can. It is also required that the material is durable and allows easy formation of the protrusion structure on the recording surface. Such materials include albumin, starch, cationic starch, gum arabic, natural resins such as sodium alginate, polyamide, polyacrylamide, polyvinylpyrrolidone, quaternized polyvinylpyrrolidone, polyethyleneimine, polyvinylpyridylium halide, melamine resin, and polyurethane. , carboxymethyl cellulose, polyvinyl alcohol, polyester, sodium polyacrylate, SBR latex, NBR latex, polyvinyl formal, polymethyl methacrylate,
polyvinyl butyral, polyacrylonitrile,
Synthetic resins such as polyvinyl chloride, polyvinyl acetate, phenolic resin, and alkyd resin can be used, and one or more of these materials can be used as desired. Furthermore, since dyes are generally used as recording agents in inkjet recording inks, it is possible to improve the adhesion of the recording agent to the recording surface of the transparent resin that can constitute the recording surface of the recording material described above. In order to do this, it is also possible to mix a material with dye fixing ability. Examples of materials having such dye fixing ability include cationic surfactants such as lauryltrimethylammonium chloride, octadecylamine acetate, and benzalkonium chloride, and dye fixing agents such as dicyandiamide and copper-containing dye fixing agents. One or more of these materials may be used as desired. Many of the materials with such dye fixation ability are
Since it is cationic, it is preferable that the above-mentioned light-transmitting resin with which these materials are mixed is a neutral or cationic polymer, but if the two do not react with each other, an anionic resin can also be used. good. In order to further improve the recording properties of the recording material, for example, silica, clay, talc, diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, Fillers such as synthetic zeolite, alumina, zinc oxide, lithopone, and sachin white may be dispersed. Furthermore, various additives such as a dispersant, a fluorescent dye, a PH adjuster, an antifoaming agent, a lubricant, and a preservative may be mixed in order to further enhance the recording characteristics or storage stability of the recording material. These additives are also added to an extent that does not impair the transparency of the recording material. The recording surface of the recording material of the present invention is formed using the various materials described above. When forming this recording surface, the recording surface is further provided with a convex portion that protrudes outward from the recording surface. For example, when the recorded surface is touched with a finger after recording, or when a piece of paper is placed over a recorded image after recording, the top portion of the protruding portion comes into contact with a substance such as a finger or paper. It is provided to block contact between the portion of the recording surface other than the contact portion, that is, most of the portion of the recorded image, and other substances. Therefore, the shape and size of this protrusion are determined from the viewpoints of its strength, function, etc. In addition to this, a structure that is easy to form is also required. An example of the structure of the convex portion on the recording surface of the recording material of the present invention that satisfies these required performances is shown in Figure 1a.
and shown in FIG. 1b. Still other examples are shown in FIGS. 2a and 2b. These protruding parts 1 are formed into a wall-like shape and protrude in a direction perpendicular to the recording surface 2.
The convex portion 1 shown in FIG. 1a has a shape that continuously partitions the recording surface 2 into a square shape, and in FIG. 2a, a regular hexagonal shape. Each unit of the wall has a convex part 1
are regularly provided on the recording surface 2, sharing a part of the recording surface 2. The partition wall-like shape of the convex portions 1 which are regularly and continuously integrated is such that the top portion 3 of the convex portions 1 comes into contact with any part of the recording surface 2. For the substance that comes into contact with the recording surface 2,
It provides a shielding effect from the recorded image, is structurally strong, and is regular, making it easy to form. The cross-sectional shape of the convex portion 1 shown in FIGS. 1b and 2b is a triangular shape that protrudes from the lower part of the recording surface 2 at a predetermined height a, and The triangular top portion 3 protruding from the top portion 3 becomes the contact portion with other substances that come into contact with this portion. This contact part 3
is formed into an acute-angled apex shape, and the contact area with the contact substance can be minimized. FIGS. 3a and 3b show other examples of recording materials of the present invention. In the examples described so far, the structure of the convex part has a triangular cross section and is provided so as to continuously partition the recording surface into a square or regular hexagonal shape. In the example, the protrusion 1 on the recording surface of the recording material is
They are provided independently from each other and have a trapezoidal cross-sectional shape with a top portion 3. A good blocking effect can also be obtained with such a structure of the protrusion. The proportion of the contact portion 3 with other substances to the entire recording surface, that is, the installation density of the convex portions 1 with respect to the recording surface 2, can be determined in order to make the area of the recorded image to be protected other than this contact portion as wide as possible. It is preferable that the thickness be as small as possible, but if it is too small, the blocking function between the recorded image and other substances that come into contact with the recording surface will be degraded. Further, the height a of the protrusion is determined in relation to the blocking function, the installation density of the protrusion, the strength of the protrusion, and the like. Generally, the higher the protrusion, the better the blocking function. Moreover, when the installation density of the projections is high, the projections may be low, and when the installation density of the projections is low, it is preferable that the projections are high. Note that the structure of the protrusion on the recording surface of the recording material of the present invention is not limited to the shapes described above, but may be of any shape as long as it satisfies the required performance described above. Furthermore, an infinite number of protrusions can be provided independently or continuously at a density as required. Such a convex portion of the recording surface of the recording material of the present invention can be formed by press working, It can be obtained by processing and shaping the recording surface by a known method such as a molding method or a photoetching method. The recording material of the present invention having a recording surface having the above-described structure may be a single sheet-like material or a multi-layered material having a recording layer provided on a transparent base material. good. A suitable method for forming a translucent recording material made of a single sheet is, for example, using a hot roll to knead and heat-expand the various materials that can form the recording surface of the recording material. After that, the method of forming protrusions on the recording surface by the method described above, the various materials mentioned above are dissolved in a suitable solvent, and a mold of the desired structure of the protrusions is provided on the surface of a suitable support. Examples include a method in which the recording material is coated on a substrate, dried, and then the recording material is peeled from the support. In addition, depending on the combination of various materials that can make up the recording surface of the recording material, if sufficient film formability cannot be obtained or if the strength is not sufficient as a single sheet, it is necessary to Using a base material, a recording layer having the above-mentioned convex portions on its recording surface is provided on the base material to form a recording material, thereby reinforcing the strength of the recording material. Examples of such light-transmitting substrates include films or plates made of polyester, diacetate, triacetate, acrylic resins, polycarbonate, and glass plates. As a method for forming the recording material of the present invention having a multilayer structure, a coating liquid prepared by dissolving or dispersing the various materials that can constitute the recording surface of the recording material in an appropriate solvent is used, for example. It is coated on a transparent substrate by a method such as a roll coating method, a rod bar coating method, a spray coating method, an air knife coating method, etc., and then quickly dried to form a recording layer, followed by the above-mentioned press processing method or photo etching. In the process of forming a recording layer on a transparent substrate, a method such as a mold processing method is applied to form a recording layer. A method of forming a convex portion at the same time as forming the convex portion can be applied. It is desirable that the thickness of the recording layer on the transparent substrate is usually about 0.5 to 50 .mu.m, preferably about 1 to 30 .mu.m after drying. The recording material of the present invention formed as described above is a translucent recording material having sufficient translucency. In the present invention, sufficient light transmittance means that the recording material exhibits a linear transmittance of at least 2% or more, and preferably a linear transmittance of 10% or more. If the linear transmittance is 2% or more, for example, OHP
It is possible to project the recorded image onto a screen and observe it, and in order to clearly observe the details of the recorded image, the in-line transmittance must be 10% or more. The linear transmittance T (%) referred to here means that the light is incident perpendicularly to the sample, passes through the sample, passes through the receiving side slit on the extension of the incident optical path, which is at least 8 cm away from the sample, and enters the detector. The spectral transmittance of the received straight light is measured using, for example, a 323-type Hitachi self-recording spectrophotometer (manufactured by Hitachi, Ltd.), and the Y value of the tristimulus value of the color is determined from the measured spectral transmittance. This is the value obtained from the following formula. T=Y/Y ⁰ ×100 T ; Linear transmittance Y ; Y value of sample Y ₀ ; Y value of blank Therefore, the linear transmittance referred to in the present invention is for straight light, and the diffuse transmittance (sample's Transmittance by diffused light, such as setting an integrating sphere behind the sample and calculating the transmittance including diffused light, and opacity (place a white and black backing on the back of the sample and calculate the ratio between them) This is different from the method used to evaluate optical properties. Note that the recording material of the present invention does not necessarily have to be colorless, and may be a colored translucent recording material. The recording material of the present invention as described above has a unique structure of the protrusions, that is, the top portions of the protrusions come into contact with each other to cut off contact between the recorded image and the substance that contacts the recording surface. In addition, almost all parts of the recorded image can be protected from substances that come into contact with the recording surface. Therefore, even if the ink is not dry or fixed immediately after recording, the recorded image may not be visible on hands, clothes, etc.
Even if it comes into contact with a recording device or general office paper, ink will not adhere to or transfer to them, and the recorded image will not be damaged, allowing the recorded image to be used immediately for the intended purpose. It became.
Furthermore, recorded images with excellent long-term storage stability can be obtained. Moreover, the recording material of the present invention is a slide or an OHP.
It has sufficient translucency for use in optical equipment such as It is possible to obtain clear images, and is used for observation by projecting the recorded image onto a screen using optical equipment such as slides and OHPs, color separation plates when creating positive plates for color printing, or liquid crystals, etc. It has become possible to apply images recorded by the inkjet recording method to transmission observation applications such as CMF used in color displays. Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 A polyethylene terephthalate film (manufactured by ICI) with a thickness of 100 μm was used as a transparent base material, and a coating solution with the following composition was applied onto this film using a plate coater method so that the film thickness after drying was 30 μm. The surface of the recording layer is coated with the same color as shown in FIG. 1a, partial view of the recording layer surface in FIG. 1a, and A- in FIG. 1a in FIG. 1b. The structure shown in the partial cross-sectional view taken along line B perpendicular to the surface of the recording layer (height a of the protruding part, 20 μm; width c of the bottom of the protruding part, 40 μm; distance b, 260 μm). Coating liquid composition: Soluble nylon 30 parts by weight (Torezin F-30 manufactured by Teikoku Kagaku) Isopropanol 50 parts by weight Water 20 parts by weight This recording material was coated with the following four types of ink using a piezo vibrator. On-demand inkjet recording head that ejects ink (ejection orifice diameter 65 μm, piezo vibrator drive voltage 60 V,
Inkjet recording was performed using a recording device with a frequency of 4 KHz). Ink composition: Yellow ink, CI Acid Yellow 23 2 parts by weight diethylene glycol 15 parts by weight water 85 parts by weight Red ink, CI Acid Yellow 37 2 parts by weight diethylene glycol 15 parts by weight water 85 parts by weight Blue ink, CI Direct Blue 86 2 parts by weight diethylene glycol 15 parts by weight Water 85 parts by weight Black ink, CI Direct Black 19 2 parts by weight Diethylene glycol 15 parts by weight Water 85 parts by weight The evaluation results are shown in Table 1. Each evaluation item in Table 1 was measured according to the following method. 1. Ink fixation time was measured by leaving the recording material at room temperature after recording, and measuring the time until the ink dried without adhering to the finger when touching the recorded image. 2. In-line transmittance was measured using a Hitachi spectrophotometer model 323 (manufactured by Hitachi, Ltd.) according to the above definition without recording on the recording material. 3. Dot density was measured for black dots using Sakura Microdensidometer PDM-5 (manufactured by Konishiroku Photo Industry Co., Ltd.) by applying JIS K 7505 to printed microdots. 4. OHP suitability was measured using a typical example of optical equipment, and was determined by projecting a print onto a screen using OHP and visually observing it. 〇: The non-recorded area is a little dark, the OD of the recorded image is a little low, and lines with a pitch width of 1 mm and a thickness of 0.3 mm cannot be clearly distinguished. △, the non-recorded area is quite dark, the OD of the recorded image is quite low, and the pitch width is 1
If the line of 0.5 mm in thickness could not be clearly distinguished or the non-recorded area and the recorded image could not be distinguished, it was marked as ×. Example 2 A polyethylene terephthalate film (manufactured by ICI) with a thickness of 80 μm was used as a transparent base material, and a coating solution with the following composition was applied onto this film using a plate coater method so that the film thickness after drying was 10 μm. The film was coated using the following methods and dried by heat treatment at 100°C for 20 minutes. Coating liquid composition: Polyvinyl alcohol 10 parts by weight (PVA-HC manufactured by Kuraray) Polyethyleneimine 0.5 parts by weight (P-1000 manufactured by Nippon Shokubai Chemical) Water 90 parts by weight In addition, a dry film (Footek, film thickness 30 μm) was applied on the recording layer. Press-bonded, exposed to light using a photomask, developed with chlorocene, and further
The recording layer was thermally cured at 150°C for 30 minutes, and the structure shown in Figures 2a and 2b (the height of the protrusion was a,
Width c of the bottom of the protruding portion was 30 μm; distance b between the bottom ends of the protruding portion was 220 μm). Inkjet recording similar to Example 1 was performed on this recording material. Table 1 shows the evaluation results of the recording characteristics of the recording material and the image characteristics of the recorded prints obtained in this example, which were conducted according to the method of Example 1. Example 3 Using the same transparent base material and coating liquid as those used in Example 1 and following the method of Example 1, the structures shown in FIGS. 3a and 3b were formed on the surface of the recording layer ( Height of the protrusion a, 20 μm; distance b between the bottom edges of the protrusion,
The width c at the bottom of the protrusion was 40 μm; the width d at the top of the protrusion was 20 μm. Inkjet recording similar to Example 1 was performed on this recording material. Table 1 shows the evaluation results of the recording characteristics of the recording material and the image characteristics of the recorded prints obtained in this example, which were conducted according to the method of Example 1. Comparative Example 1 Inkjet recording was performed in the same manner as in Example 1 using a 100 μm thick triacetate film (manufactured by Fuji Photo Film) as the recording material. Table 1 shows the evaluation results of the recording characteristics of the recording material used in this comparative example and the image characteristics of the recorded prints, which were conducted according to the method of Example 1. Comparative Example 2 Commercially available OHP film (product name: NP-DRY
Inkjet recording was carried out in the same manner as in Example 1 using Transparency (manufactured by Canon Inc.) as the recording material. Table 1 shows the evaluation results of the recording characteristics of the recording material used in this comparative example and the image characteristics of the recorded prints, which were conducted according to the method of Example 1. Comparative example 3 Commercially available tracing paper (thickness, approximately 80 μm)
Inkjet recording was carried out in the same manner as in Example 1 using as the recording material. Table 1 shows the evaluation results of the recording characteristics of the recording material used in this comparative example and the image characteristics of the recorded prints, which were conducted according to the method of Example 1. 【table】

[Brief explanation of the drawing]

1a, 2a, and 3a are partial plan views of the recording surface of an embodiment of the recording material of the present invention;
Figure b, Figure 2 b and Figure 3 b are the same as Figure 1 a, Figure 2.
FIG. 3 is a partial cross-sectional view of the recording material taken along line A-B in FIG. 3a and FIG. 3a. In the figure, 1 is the protrusion, 2 is the recording surface, 3 is the top of the protrusion (the part in contact with another substance), a is the height of the protrusion, and b is the two protrusions. Distance of bottom edge, c
is the width of the bottom of the protrusion, and d is the width of the top of the protrusion.

Claims (1)

[Scope of Claims] 1. The recording surface has a plurality of regions with a size of several hundred μm x several hundred μm divided by partitions protruding from the recording surface, and the in-line transmittance is 2% or more. A recording material for inkjet recording characterized by the following. 2. The above-mentioned recording material whose recording surface has a plurality of regions of several hundred μm x several hundred μm in size divided by partitions protruding from the recording surface, and whose in-line transmittance is 2% or more. An inkjet recording method characterized in that recording is performed by applying ink droplets to a recording surface.