JPS58177390A - Recording sheet - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording sheet that is recorded using colored ink, and the images and characters recorded on the IC141 sheet have a high density, a high degree of resolution, and are not affected by the environment. This relates to inkjet recording sheets, which are rarely received.

Inkjet recording includes various methods, including means for generating minute ink droplets with a diameter of 2ON150β, and means for ejecting the droplets to a predetermined position on recording paper. Droplets are generated by pressurized ink being ejected from a fine nozzle orifice with a diameter of 30 to 150 μm.The droplets are charged and manipulated by an electric field to position the droplets at a predetermined position on the recording paper. Electrostatic deflection type inkjet method that applies slight pressure to the ink to form a meniscus at the tip of the nozzle, and also applies a high voltage between the nozzle and the opposing electrode to uniformly charge the ink using a strong electric field. Electric field control type inkjet method in which particles are received by a recording paper provided on the surface of a counter electrode, and a double drop-on-demand violet inkjet method in which droplets are generated only at the necessary locations through multiple nozzle orifices and are ejected directly onto the recording paper. and so on. Since both are inkjet methods, they use liquid ink, so the ink that adheres to the recording paper must be absorbed into the corners and dry, and the direction of absorption on the recording paper must be uniform and circular. Recording paper KgI is simultaneously required to have contradictory properties such as low absorption in the lateral direction, high resolution without bleeding, and high image density. In addition to these inkjet suitability, in the above-mentioned electric field controlled inkjet method, when the Fi environment humidity is low, the minute ink droplets do not reach the predetermined position, reducing the dissolving performance, and when the surrounding area becomes dirty with flying particles, they become thicker. Development IP&A] requires performance that is not affected by environmental humidity.

General printing Kl! High-quality paper and coated paper used for electrostatic recording, electrostatic recording paper with a conductive layer used for electrostatic recording, and so-called baryta paper used as a base for photographic printing paper.
Resin-coated paper has extremely poor ink absorption, so when used for inkjet recording, ink may remain on the surface for a long time, come into contact with parts of the device, be touched by the handler, or be continuously discharged. If the sheets overlap and the recording surface is rubbed, the image will be smeared with residual ink. 2 to 4 images in the same place in high-density image areas or multicolor recording
If the ink dots of different colors overlap, there is a large amount of ink.
There are problems such as the ink mixing without being absorbed or flowing out, so it is not practical. In order to solve these problems, the present inventors have proposed a method for improving resolution, color properties, color density, absorption, roundness, etc. by providing a synthetic grating layer on the surface. . However, synthetic silica inherently has almost no electrical conductivity; rather, the synthetic silica layer acts as an insulating layer, and when recording paper provided with an ink-receiving layer mainly made of synthetic silica is used, for example, in an electric field-controlled inkjet system, the environmental temperature increases. When the temperature is low, the minute ink spray is in place @
It has been found that a so-called sputtering phenomenon occurs in which the resolution is lowered and the area around the corner becomes dirty.

The inventors have the nine inkjet suitability mentioned above,
In order to obtain an inkjet recording paper that is not affected by Kll mass temperature, various studies have been carried out and the present invention has been completed. The present invention relates to an inkjet recording paper that has high ink absorption capacity, high resolution, and is less affected by environmental temperature, and has the following requirements. That is, in a recording sheet made of a general company with an ink-receiving layer made of at least a synthetic rubbing force and an aqueous adhesive on the support surface 11iK, a conductive agent containing an a14-grade ammonium salt in the support or ink-receiving layer is used. To provide an inkjet recording sheet in which the OR surface resistance of the ink-receiving surface is 9×1 G''Ω or less even when the environmental humidity is low.

The synthetic silica used in this product is the so-called white carbon produced by thermal decomposition of silicon tetrachloride, compound precipitation products with sodium silicate acid, carbon dioxide, ammonium salts, etc., and sodium silicate acid. Silica sol obtained through metathesis or an ion exchange resin layer, or colloidal silica obtained by heating and aging this silica sol, and by gelling the silica sol and changing the production conditions, primary particles of several millimicrons to 10 millimicrons can form siloxane bonds. Silica gel, which has become a three-dimensional secondary particle, and also silica sol, sodium silicate, sodium aluminate, etc., are heated at 80°C to 120°C as starting materials to produce so-called synthetic molecular sieves, etc.
It is a synthetic silicon compound mainly composed of silicic acid. Examples of water-based adhesives include starches such as oxidized starch, etherified starch, esterified starch, and dextrif; cellulose conductors such as carboxymethyl cellulose and hydroxyethyl cellulose; casein, gelatin, soybean protein, polyvinyl alcohol and its derivatives; Conjugated diene polymer latex such as maleic acid resin, ordinary styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, acrylic polymer latex such as polymer or copolymer of acrylic acid ester and methacrylic acid ester , vinyl polymer latex such as ethylene-vinyl acetate copolymer, functional group-modified polymer latex with monomers containing functional groups such as carboxyl groups of these various polymers,
Thermosetting synthetic resin adhesives such as melamine resin, etc.
From the viewpoint of synthetic silica 011 adhesion, polyvinyl alcohol or polyvinyl alcohol trout conductor is preferred.

These adhesives contain inorganic pigments mainly composed of synthetic silica10.
0 parts by weight, 2 parts by weight to 30 parts by weight, preferably F
is added in an amount of 20 parts by weight.

Furthermore, if necessary, white pigments other than synthetic silica, raw material dispersants, thickeners, linear modifiers, antifoaming agents, foam inhibitors, mold release agents, fluorescent agents, colorants, etc. may be appropriately blended to improve the characteristics. There is no problem as long as it is not damaged.

The quaternary ammonium salt type conductive agent as used in the present invention is, for example, an acrylic-based cationic polymer consisting of a structural unit as exemplified by the formula (formula ←). Cationic polymer, formula (
Polyvinylpyridine-based polymers consisting of structural units exemplified by formula (3), cyclic integral type polymers exemplified by formula (4), linear integral type polymers such as those exemplified by formula (5), and furthermore, 6), as shown in (3
) (4) So-called pendant IIKm is a polymer of aromatic vinyl monomers having two or more quaternary ammonium ion groups.

The bond types that make up Y include T mido bonds, ester bonds, ether bonds, imino bonds, methylene bonds, methylene bonds containing substituents, and combinations of some of these.6 The anion P is 9 For example, FO ,C
1♀8, θ and. ,Oka,. −. These include alkyl sulfates such as 7-toxysulfate, ethoxysulfate, dodecylbenzenesulfonic acid, and dodecylsulfonic acid, and dioctyl phosphate.

Methods for incorporating these quaternary ammonium salt layer conductive agents into a recording sheet include a method in which an ink-receiving layer is provided after impregnating the support with P applied in advance, and a method in which an ink-receiving layer is provided after the ink-receiving layer is provided. In addition, after forming an ink-receiving layer, a coating solution containing a quaternary ammonium salt can be applied to the surface of the ink-receiving layer or the back surface of the support. The content varies depending on the type and effect of the quaternary ammonium salt conductive agent, but approximately α2t
/IIIP~3 f/a/, preferably o,
20℃, 30%R by containing st/-~zt/d
The surface resistance of the ink-receiving layer surface at the time of H may be set to 9×10 11 Ω or less. It is not clear why the sputtering phenomenon does not occur by lowering the surface resistance, but in the electric field control box/kujetsu method, a high voltage is applied to the nozzle and the opposing electrode, which charges the nozzle and generates nine ink particles. However, if the ink particles attracted to the counter electrode are received by a sheet of paper placed just before the counter electrode, the ink particles that are generated are also 1'), but the number of ink particles that are generated is not 1'), but is rounded at a predetermined position. A plurality of ink particles will adhere. However, if the charge carried by the first ink particle does not escape, the next particle will be charged to the same potential, so the first particle will stick to it and be scattered around it, making it difficult to approach the other place.9 (Therefore, the ink is water-based.) It is harder for electric charge to escape with oil-based ink. It is thought that such a phenomenon causes a decrease in resolution and a sputtering phenomenon.

Therefore, if the charges carried by ink particles are released one by one by lowering the surface resistance, it becomes possible for ink particles that arrive one after another to adhere to the same location without being disturbed by charges. This is considered to be the case. It was discovered that even when the environmental humidity is low, the above-mentioned effect appears if the surface resistance is less than 9 x 1 @''Ω.

Furthermore, when these quaternary ammonium chloride conductive agents are included in the ink-receiving layer a', the water-based ink becomes water-resistant, and the image remains intact even if water is deposited on the image. It has also been found that it has the secondary effect of not being eluted or disappearing9. Such water resistance is -80s in direct dye and acid dye molecules in water-based ink.
This is thought to be because the N a -fMJsH and -NH2 groups combine with the cation moiety of the quaternary ammonium salt conductive agent contained in the ink receiving layer to become an insoluble salt.
This effect is merely a secondary effect, and the main effect of the present invention is to impart conductivity to the recording sheet.

The support used in the present invention is made of thermoplastic paper.
A sheet material of I4m1 film 01lQ is used. The material is not limited to 4I, and suitable sizing can be used such as good paper, polyester, polystyrene, polyvinyl chloride, polymethyl methacrylate, cellulose acetate, polyethylene, polycarbonate, and other films.

Even if these papers contain fillers, they are still thermoplastic.
ll film may be a transparent film that does not contain surrounding pigment, but it may be filled with a certain percentage of white pigment or may be filled with mold.
It may be a white film.

As the white pigment to be filled, for example, titanium oxide, am
O4ho such as calcium, calcium carbonate, silica, clay, talc, zinc oxide, etc. can be used. These supports ID1i*:) vh limited to -41 l1itk
Those in which vh is usually 1@j1m to 3GOJ1mO are often used. In addition, in order to improve the adhesion between the film and the ink-receiving layer OII, there may be a zero layer.10 In the present invention, a coating factory is required for the method of incorporating the 1114-grade ammonium salt conductive layer into the support or the ink-receiving layer. In this case, any of the blade coaters, T-knife coaters, roll coaters, plush coaters, curtain coaters, bar coaters, gravure coaters, spray coaters, etc. that are generally used as coating machines can be used. Furthermore, when the support is paper, it is also possible to apply a size press on a paper machine, a gate roll, a device, etc.

A layer of quaternary ammonium i is provided on the support.
J[fJi A circular sheet containing a conductive agent can be used as is as a recording sheet according to the present invention,
For example, it is possible to give the surface smoothness by applying heat and pressure using a super calender, a gloss calender, etc. and passing it between one lunip and the like.

The method for measuring surface resistance of the present invention is based on the method of JIS K6911 and uses an electrode manufactured by Takeda Baken (MODRL-T&-42).
) and an oscillating capacitance low current potential needle (T&-84M).

Using the sheet of the present invention, the inkjet method is used.
When drawing an image, - the color tone of the image is clear and the resolution is good;
Images with sufficient practical value can be obtained in which the ink absorption capacity is large and the ink O absorption speed is fast, and the suitability for O wick jetting hardly changes due to changes in environmental humidity.

Examples of the present feathers will be described below, but these Of4
It is not determined by. In addition, parts and parts shown in Examples mean parts and weights.

Methods for measuring various physical property values in Examples are shown below.

(1) Ink absorption speed The water-based inkjet ink I/I-1000 is deposited on the surface and the time from 9 seconds until all of it is absorbed is determined under a microscope. (Seconds) If it is less than 2 seconds, Arashi is good (2) Resolution Aqueous inkjet ink diameter 100 Ink droplets are attached to the surface, and after being absorbed, the diameter is calculated by keeping the marked area of the ink droplets constant. did. (#,), small diameter v
h1i! The resolution is fine.

(3) Chromaticity Four colors, cyan, magenta, yellow, and black, were recorded using an inkjet device, and the color densities were measured using a Sakura densitometer PD-Mu45. (0,D
) (4) Sputtering at 20° C., printing was performed using an electric field controlled inkjet device, and the scattering state of the oil-based ink droplets was determined from the printing direction.

(5) Water-resistant water-based ink (magenta) printing 4' in #1 water (soaked for 1 hour, check the density of the printed area on Sakura densitometer P)
The water resistance difference measured with DA4S can be used as an indicator of water resistance. (The larger the value, the less water resistance is required.) Examples 1 to 4 Synthetic silica (Vitaseal manufactured by Taki Chemical Co., Ltd. $1500
) gill, 15 parts of heavy calcium carbonate (Niscaron@200 manufactured by Sankisake), water-based adhesive (manufactured by Kuraray, PVA1)
17) Spread a 18 KOIk liquid containing 15 parts of a small amount of a biased dispersant, an antifoaming agent, etc. on the base paper above.
/j (solid content) by coating with an air knife coater.

In addition, I will explain the wrinkles to the 1iK4 and the 9th Chemistat 5zoo
(Quaternary am/monium salt lidding polymer manufactured by Sanyo Chemical Co., Ltd.) was sprayed to a solid content of 117 d, uniformly coated and dried, and then super calendered to make the surface smooth. Recording paper and kayak 9 A/
Example 20 Brass paper was obtained by dissolving L/Jin Bc-003 (Nippon Kakenten, JI quaternary ammonium Shioya polymer) in 4 and applying I & M in the same manner. More 1c8T-soo
oW (Mitsubishi Yuka Exhibition, Iris quaternary ammonium salt lid polymer)
Dissolved in t6, solid content L! i t / d Kt
Example 5 ole sickle paper was prepared by spraying it onto a sea urchin, coating it uniformly, drying it, and applying a super calendar.

In addition, Cortaminkan 6-P (manufactured by Kao Sekiken Co., Ltd., quaternary ammonium salt sublimation activator was dissolved in 6j1, and the solid content was L.
Spray to 8f/- and apply evenly and dry.
When hanging a super calendar, use the recording paper of Example 4 as a friend.

The results of Examples 1 to 4 in which the inkjet suitability was maintained on recording M paper are shown in Table (2).

Comparative Examples 1 to 3 Comparative Example 10 silver paper was prepared by supercalendering the same spray value paper used in Example 1 but only provided with an ink receiving layer. Also, dissolve Chemistat auto (anionic moat polymer manufactured by Sanyo Chemical Co., Ltd.) by 4XK dropwise, spray it to a solid content of 1 f/dK, dry it on a homogeneous Klk cloth, and then apply a super calender to smooth the surface. The material was used as comparative example 20 brass paper. Furthermore, Electro Stripper K (alkyl phosphate potassium salt conductive surfactant manufactured by Kao Sekiken Co., Ltd.) was dissolved in 6K, and the FiA was heated for 11 minutes. @t / d K Spray it on a uniform cloth, dry it for 90 minutes, and then apply a super calendar to make it a ratio IIRf13O1e brass paper.

Table IK shows the results of determining inkjet suitability for the le sickle papers of Comparative Examples 1 to 3.

Table 1 It is clearly seen from Table I that Examples 1 to 4 according to Honjitsu@ had good ink retention, good resolution, good color properties, and very good sputtering and water resistance.

Examples 5 to 8 Synthetic squirt force (Fuji Devin Thyloid 620) 100
20 parts of water-based adhesive (PVA117 manufactured by Kuraray), a small amount of Sono Fake, IT wave, antifoaming agent, etc. mI 1 min concentration 20
Apply the coating liquid to a coated base paper using a powder press 21/d with a weighing weight of 77 f/ds and a Steckcht size of 43 seconds to give a coating weight of 1 Ijlk, l・t, /r (solid content). It was smeared with an air knife coater. Furthermore, in the smearing direction, Chemistat 6300 (manufactured by Sanyo Kasei, No. 441 ammonium salt conductive polymer) dissolved in l~4xK was applied in m-type portions at 0.6 f/d and L Of/ds, respectively.
It was coated and dried using an air knife coater to give a ratio of t-5f/w12.0/11/, and then the surface was smoothed using a super calender to form a smooth coating.Example 5゜□ 6.7. BID marking paper was used.

Regarding these papers, inkjet suitability and 20%
The surface resistance at RH of 30 °C and 30 °C was adjusted, and the results are shown in Table 3.

Comparison @ 4 Good for use in Examples 5 to 8, 4th @ 77 monium salt The paper before being coated with conductive polymer was coated with only water, dried, and supercalendered as a comparative example] and the same Kll.
Table ■ shows the nine conclusions.

Table ■ As is clear from Table ■, it can be seen that the examples in which the surface resistance at 20° C. and 5 ox RH is II×10” or less have improved sputtering and water resistance in addition to inkjet suitability.

Claims (1)

[Scope of Claims] l In an inkjet recording sheet in which a recording is obtained by jetting a recording liquid onto a recording surface which is provided with an ink-receiving layer made of at least synthetic silica and a water-based adhesive on the surface of a support, A recording sheet, characterized in that the ink-receiving layer or the support contains a quaternary ammonium salt type conductive agent, and the ink-receiving layer has a surface resistance of IXI 1 Ω or less when heated at 20C, 30°C. 2 The method of ejecting the recording liquid is a so-called method in which a nozzle and a counter electrode are provided, and ink is ejected by applying a voltage between the wrinkled nozzle and the counter electrode, and the ink is charged and flies to reach the recording sheet. A recording sheet according to claim 1, which is recorded by an electric field controlled inkjet device. 3. The recording sheet according to claim 1 or 2, wherein the recording liquid mainly consists of a dye and a non-aqueous solvent.