JPH0536237B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a recording material particularly excellent in ink receptivity and excellent clarity of recorded images, particularly to a recording material for inkjet recording and a method for forming color images. [Prior Art] The inkjet recording method uses various ink (recording liquid) ejection methods, such as an electrostatic suction method, a method that applies mechanical vibration or displacement to the recording liquid using a piezoelectric element, and a method that applies mechanical vibration or displacement to the recording liquid using a piezoelectric element. Recording is performed by generating and flying ink droplets using a method that uses foaming and the resulting pressure, and some or all of these droplets adhere to a recording material such as paper, but it does not generate noise. It is attracting attention as a recording method that allows high-speed printing and multi-color printing. Water-based inks are mainly used for inkjet recording in terms of safety and recording characteristics, and polyhydric alcohols are added to prevent nozzle clogging and improve ejection stability. There are many. Conventionally, the recording material used in this inkjet recording method is a recording material called ordinary paper or inkjet recording paper, which has a porous ink-receiving layer on a base material. . However, as the performance of inkjet recording apparatuses improves and becomes more widespread, such as faster recording speeds and multicolor recording, more sophisticated and wide-ranging properties are being required of recording materials. In other words, the recording material for inkjet recording in order to obtain high-resolution, high-quality recorded images must (1) be able to receive ink as quickly as possible on the recording material, and (2) have overlapping ink dots. (3) Ink droplets do not spread on the recording material and the diameter of the ink dot does not become larger than necessary, (4) ) The shape of the ink dot must be close to a perfect circle and its circumference must be smooth; (5) The OD (optical density) of the ink dot must be high and the periphery of the dot must not be blurred. There is. Furthermore, in order to obtain high-resolution recorded image quality comparable to color recording using multicolor inkjet recording, in addition to the above-mentioned performance requirements, (6) the coloring components of the ink must have excellent coloring properties; (7) ) Since the same number of droplets as the number of ink colors may overlap and adhere to the same location, there are important requirements for performance such as particularly excellent ink fixing properties, (8) high whiteness, etc. Ru. [Problems to be Solved by the Invention] However, the reality is that there is still no known recording material that satisfies all of these required performances. In addition, most conventional recording materials for surface image observation use a method in which a porous ink-receiving layer is provided on the surface, and the recording liquid is received in the porous voids to fix the recording agent. Since the recording agent penetrated deeply into the ink-receiving layer, the clarity was low. On the other hand, when the surface of the ink-receiving layer is non-porous, non-volatile components such as polyhydric alcohols in the ink remain on the surface of the recording material for a long time after recording, and the drying and fixing time of the ink is long. Another disadvantage is that clothing may get dirty or the recorded image may be damaged if it comes into contact with the recorded image. An object of the present invention is to provide an ink-receptive recording material particularly excellent in ink-receptivity and clarity of recorded images, and a method of forming a color image using the same. [Means for Solving the Problems] The above object is achieved by the following present invention. That is, the present invention provides a recording material comprising a base material and an ink receiving layer provided on the base material,
An ink-receptive recording material characterized in that the opacity of the base material according to JIS-P-8138 is 70% or more, and the opacity of the ink-receiving layer is not greater than that of the base material, and such recording material On the other hand, this method uses yellow, magenta, cyan, and black inks to form a color image. [Function] The recording material of the present invention consists of a base material as a support and an ink receiving layer provided on the surface thereof. The base materials used in the present invention include general paper, cloth,
In addition to wood, metal plates, synthetic paper, etc., films such as polyester resin, diacetate resin, triacetate resin, acrylic resin, polycarbonate resin, polyvinyl chloride resin, polyimide resin, cellophane, celluloid, etc. Alternatively, plates, glass plates, etc. made opaque by a known method may be used. In addition, the ink receiving layer in the present invention is made of a material that has an affinity for water and polyhydric alcohol, which are liquid components of the ink, such as polyvinyl alcohol, albumin, gelatin, casein, starch, cationic starch, gum arabic, and sodium marginate. natural resins, polyamides, polyvinylpyrrolidone,
Quaternized polyvinylpyrrolidone, polyethyleneimine, polyvinylpyridylium halide, melamine resin, polyurethane, carboxymethylcellulose, polyester, SBR latex, NBR latex, polyvinyl formal, polymethyl methacrylate, polyvinyl butyral, polyacrylonitrile, polyvinyl chloride, polyacetic acid vinyl,
Synthetic resins such as phenolic resins and alkyd resins may be mentioned, and one or more of these materials may be used as desired. In addition, in order to further improve the ink receptivity of the ink receptive layer or to make it opaque, for example, silica, clay, talc, diatomaceous earth, calcium carbonate, sulfuric acid, calcium, barium sulfate,
Fillers such as aluminum silicate, synthetic zeolites, alumina, zinc oxide, lithopone, satin white, etc. can also be dispersed in the ink-receiving layer. The amount of the filler added is not particularly limited as long as the film-forming properties of the ink-receiving layer are not impaired. As a method for forming such an ink-receiving layer, a coating solution is prepared by dissolving or dispersing the above-mentioned resin and, if necessary, a filler in a suitable solvent, and the coating solution is coated by, for example, a roll coating method. , a method in which the mixture is coated on a substrate by a known method such as a rod bar coating method, a spray coating method, an air knife coating method, and the like, and then quickly dried. Other methods may also be used, such as forming a single sheet for the ink-receiving layer from a material such as, and then laminating the sheet to the above-mentioned base material. If necessary, a cast coating method may be used in addition to the above-mentioned coating method, or glossing may be performed using a gloss roll. In the present invention as described above, the thickness of the ink receiving layer formed on the substrate is usually about 0.1 to 200 μm, preferably about 1 to 50 μm. The present invention has been described above by exemplifying typical aspects of the recording material of the present invention, but of course the recording material of the present invention is not limited to these aspects. still,
In either embodiment, the ink-receiving layer may contain various known additives such as dispersants, fluorescent dyes, PH regulators, antifoaming agents, lubricants, preservatives, and surfactants. can. The recording material of the present invention is based on JIS-P-8138.
It is essential that the opacity of the base material is 70% or more, and more preferably, it is desirable that the opacity is 90% or more. In general, recorded materials such as printed matter, photographs, written records, etc. are illuminated with a diffused light beam by direct or indirect illumination, and the light beam is reflected and absorbed by the recorded material to emit diffused light corresponding to a recorded image. If the opacity of the base material is less than 70%, the transmittance of the incident light beam to the recording material is high, so the light beam reflected by the recording material decreases, resulting in only a dark and unclear image. do not have. On the other hand, the ink-receiving layer needs to have an opacity equal to or lower than that of the substrate. Generally, the dye in the ink adhering to the surface of the ink-receiving layer permeates and diffuses into the ink-receiving layer, and is retained in a dispersed form within the ink-receiving layer. Therefore, when the opacity of the ink-receiving layer is high, the reflectance of the incident light beam by the ink-receiving layer becomes high, so that the light beam reflected after reaching the dye dispersed in the ink-receiving layer is As a result, the recorded image looks whitish and dull, and a clear image cannot be obtained. Therefore, in order to obtain images with excellent clarity,
It is desirable for the ink-receiving layer to be more transparent, and conversely for the substrate to have a high reflectance of incident light.
That is, the ink-receiving layer needs to have a lower or equal opacity than the base material, but preferably in the present invention, it is desirable that the difference in opacity is large. Hereinafter, the recording material of the present invention will be explained in more detail according to Examples. In addition, parts in the text are based on weight. Example 1 Cast coated paper (mirror coat; manufactured by Kanzaki Paper Co., Ltd.) was used as a base material, and the following composition was coated onto this base material using a bar coater method so that the dry film thickness was 5 μm, and the mixture was heated at 100°C. The material was dried for 5 minutes to obtain a recording material (1) of the present invention. Polyvinylpyrrolidone (PVP K-90; manufactured by GAF) 5 parts Polyvinyl alcohol (B-20; manufactured by Denki Kagaku Kogyo) 5 parts Water 90 parts Example 2 Art paper (OK Art Post; manufactured by Oji Paper) was used as the base material. Then, a recording material (2) of the present invention was obtained in the same manner as in Example 1 by using the same composition as in Example 1 on this base material. Example 3 The same art paper as in Example 2 was used as a base material, and the following composition was coated onto this base material using a bar coater method so that the dry film thickness was 7 μm, and the mixture was heated at 80°C.
After drying for 10 minutes, a recording material (3) of the present invention was obtained. Polyvinyl alcohol (Gohsenol KH-17; manufactured by Nippon Gohsei)
5 parts Talc (SWS; manufactured by Tsuchiya Kaolin) 5 parts Water 90 parts Example 4 Synthetic paper (YUPO; manufactured by Oji Yuka Synthetic Paper) was used as a base material, and the following composition was applied on this base material to a dry film thickness. The recording material (4) of the present invention was coated using a bar coater method so that the thickness was 5 μm, and dried at 80°C for 20 minutes.
I got it. Hydroxyethyl cellulose (HEC AG-15; manufactured by Fuji Chemical) 5 parts Water 95 parts Comparative example 1 Polyethylene terephthalate film (manufactured by Toray Industries) was used as a base material, and the same coating as in Example 1 was applied on this base material. A recording material (5) was obtained in the same manner as in Example 1 using the composition. Comparative Example 2 A recording material (6) was obtained in the same manner as in Example 1 by using the following coating composition on the same substrate as in Example 1. Polyvinyl alcohol (K-17S; manufactured by Denki Kagaku Kogyo) 3 parts Titanium oxide (Tiepeque R-680; manufactured by Ishihara Sangyo) 17 parts Water 80 parts Comparative example 3 As the base material, the same art paper as in Example 2 was used, On this base material, using the following coating composition,
A recording material (7) was obtained in the same manner as in Example 1. Polyvinyl alcohol (K-17S; manufactured by Denki Kagaku Kogyo) 2 parts Clay (Super Floss: manufactured by Tsuchiya Kaolin) 18 parts Water 80 parts The following four types of inks were applied to the recording materials of the above examples and comparative examples. Inkjet recording was carried out using a recording apparatus having an on-demand type inkjet recording head (discharge orifice diameter 60 μm, piezoelectric vibrator drive voltage 70V, frequency 2KHz) that ejects ink using a piezoelectric vibrator. Yellow ink (composition) CI Direct Yellow 86 2 parts Diethylene glycol 20 parts Polyethylene glycol #200 10 parts Water 70 parts Magenta ink (composition) CI Ascended 35 2 parts Diethylene glycol 20 parts Polyethylene glycol #200 10 parts Water 70 parts Cyan ink (composition) CI Direct Blue 86 2 parts Diethylene glycol 20 parts Polyethylene glycol #200 10 parts Water 70 parts Black ink (composition) CI Food Black 2 2 parts Diethylene glycol 20 parts Polyethylene glycol #200 10 parts Water 70 parts Records of the above examples and comparative examples Table 1 shows the evaluation results for the materials. Each evaluation item in Table 1 was measured according to the following method. (1) Ink fixation time was measured by measuring the time taken for the ink to dry and stop adhering to the finger when touching the recorded image after recording. (2) Dot density was measured for black dots using Sakura Microdensidometer PDM-5 (manufactured by Konishiroku Photo Industry Co., Ltd.) by applying JIS K7505 to printed microdots.

〔effect〕

As described above, the present invention uses a recording material in which the base material has an opacity of 70% or more according to JIS-P-8138, and the ink receiving layer has an opacity lower than or equal to that of the base material. When inkjet recording is performed, a recorded image with excellent ink receptivity and clearness can be obtained. Although the recording material of the present invention has been described above based on the inkjet recording method, it goes without saying that it can also be applied to other recording methods, such as thermal recording.

Claims (1)

[Scope of Claims] 1. In a recording material consisting of a base material and an ink receiving layer provided on the base material, the opacity of the base material according to JIS-P-8138 is 70% or more, and An ink-receptive recording material characterized in that the opacity of the ink-receptive layer is not greater than that of the base material. 2. The ink-receptive recording material according to claim 1, wherein the ink-receptive layer has an opacity of 40.2% or less. 3. In a method of forming a color image on a recording material by an inkjet recording method using a plurality of color inks, yellow, magenta, cyan, and black inks are used as the color inks, and a base material and the It consists of an ink-receiving layer provided on a base material, and the opacity of the base material according to JIS-P-8138 is 70% or more, and the opacity of the ink-receiving layer is not greater than that of the base material. Characteristic color image formation method.