JPH111060A - Recording medium and inkjet recording method using this recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording medium capable of coping with inks of various compositions, having excellent ink absorbability, suppressing printing bleeding and beading, and obtaining a high image density, and inkjet recording using the same. Provide a way. SOLUTION: In a recording medium having an ink receiving layer containing alumina hydrate on a base material, the alumina hydrate exists in a non-oriented manner in the ink receiving layer, and a cross section of the ink receiving layer has an electron. When a line is made incident, the diffraction intensity fluctuation value δ of the diffraction image is 5% or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium suitable for an ink jet recording method and an ink jet recording method using the same.

[0002]

2. Description of the Related Art In an ink jet recording system, fine droplets of ink are caused to fly from nozzles and adhere to a recording medium such as paper to record images, characters, and the like. It is easy to use, has great flexibility in recording patterns, and does not require development and fixing. It is widely used in printers and other information devices such as copiers, word processors, fax machines, plotters, etc. doing.
In recent years, high-performance digital cameras, digital video,
Scanners are being provided at low cost, and in conjunction with the spread of personal computers, opportunities to output image information obtained from the scanners by an inkjet recording method are increasing. For this reason, it is required to output an image which is comparable to silver salt-based photographs and multi-color printing of a plate making method by an ink jet method. For this purpose, recording apparatuses and recording methods have been improved, such as high-speed recording, high-definition recording, and full-color recording. However, advanced characteristics have also been required for recording media.

Various types of recording media used for ink jet recording and the like have been conventionally proposed. For example, Japanese Patent Application Laid-Open No. 52-53012 discloses an ink-jet paper in which a base material having a small size is impregnated with a surface treatment paint. JP-A-53-49113 discloses an ink-jet paper in which a sheet containing urea-formalin resin powder is impregnated with a water-soluble polymer. JP-A-55-5830 discloses an ink-jet recording sheet provided with an ink-absorbing coating layer on the surface of a support, and JP-A-55-51583 discloses an amorphous recording medium as a pigment in a coating layer. An example using silica is disclosed, and JP-A-55-146786 discloses an example using a water-soluble polymer coating layer.

[0004] In recent years, attention has been paid to recording media using alumina hydrate. Since alumina hydrate has a positive charge, the ink dye is well fixed, and it has advantages over a conventional recording medium, such as high color development and high gloss image. JP-A-7-23
Japanese Patent No. 2475 discloses a recording medium in which ink absorption and bleeding are prevented by using alumina hydrate.
U.S. Pat. Nos. 4,879,166 and 5104
No. 730, JP-A-2-276670 and 4-37.
JP-A-576-576 and JP-A-5-32037 disclose recording media having a layer using alumina hydrate having a pseudo-boehmite structure.

[0005]

However, as described above, a recording medium using alumina hydrate can produce high-definition images in a short time, which is comparable to silver salt-based photographs and multicolor printing of a plate making method. In order to output, there are the following problems, and there is still room for improvement.

(1) In printing for outputting a high-definition color image in a short time, the amount of ink is large, so that the printed ink does not completely absorb in the pores but overflows on the surface of the ink receiving layer, causing bleeding. This will cause poor print quality.

(2) High-speed printing requires high ink absorption, but if the absorption speed is insufficient, beading occurs. Here, the beading is a phenomenon in which the previously applied ink dot is brought into contact with and connected to an adjacent ink dot on the recording medium before the ink dot is absorbed by the recording medium, resulting in unevenness in image density. .

(3) Japanese Patent Application Laid-Open No. 3-281384 discloses an alumina hydrate in which a columnar, aggregate oriented in a certain direction is formed, and a method of forming an ink receiving layer using the alumina hydrate. Is disclosed. Further, Japanese Unexamined Patent Application Publication No.
276670 discloses an example of a bundled alumina sol. However, alumina hydrate having such a columnar structure is likely to cause charge concentration at the edge portion of the particles, or because the particles tend to agglomerate strongly and the alumina hydrate is oriented and densely clogged. It is considered that the resistance of the ink permeation into the receiving layer increases, and beading is likely to occur in printing for outputting a high-definition color image in a short time.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. In other words, an object of the present invention is to provide a recording medium which can cope with inks of various compositions, has excellent ink absorbability, suppresses printing bleeding and beading, and provides a high image density, and an inkjet recording method using the same. And

[0010] The recording medium of the present invention is a recording medium having an ink receiving layer containing alumina hydrate on a base material, wherein the alumina hydrate is present in the ink receiving layer in a non-oriented manner. When an electron beam is incident on a cross section of the receiving layer, a diffraction intensity variation value δ of a diffraction image is 5% or less.

Further, the ink jet recording method of the present invention is characterized in that ink droplets are caused to fly and adhere to the recording medium.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The recording medium of the present invention is a recording medium containing non-oriented alumina hydrate as an essential component, and an ink mainly formed from the above alumina hydrate and a binder on a base material. A receiving layer is provided. Alumina hydrate exists non-oriented in the ink receiving layer. That is, in the alumina hydrate used in the present invention, the particles are not arranged in a certain direction in the ink receiving layer as shown in the drawing substitute photograph (observation by transmission electron microscope: 100,000 magnification) of FIG. Since the specific crystal plane is not oriented due to non-orientation, electron beam diffraction on the specific crystal plane is not emphasized, and as shown in the drawing substitute photograph (electron diffraction image) in FIG. Have a substantially constant intensity distribution.

On the other hand, as shown in the drawing substitute photograph (transmission electron microscope observation: 100,000-fold magnification) of FIG. 3, bundled alumina hydrate (boehmite) oriented in a certain direction is (02
Since the electron beam diffraction is emphasized by the (0) plane, as shown in the drawing substitute photograph (electron diffraction image) of FIG. 4, the intensity of the intensity is observed in the diffraction ring of the (020) plane.

Here, the alumina hydrate used in the present invention satisfies the condition of the following formula (1). That is, when the recording medium is cut in the thickness direction and a cross section of the ink receiving layer is irradiated with an electron beam, a ring-shaped diffraction image arranged concentrically as a transmission diffraction pattern is obtained. At this time, the diffraction intensity variation value δ of each ring-shaped diffraction image represented by the following equation (1) is 5% or less. δ = (Imax−Imin) / (Imax + Imin) × 100 (1) (where, Imax indicates the maximum value of the diffraction intensity in one ring-shaped diffraction image, and Imin indicates the minimum value) When it satisfies, especially, the ink absorption speed becomes sufficiently high, and the occurrence of beading can be effectively prevented.

The alumina hydrate according to the present invention is represented by the following general formula (2). Al ₂ O _3-n (OH) _2n · mH ₂ O (2) In the formula, n represents an integer of 1, 2 or 3, and m
Represents a value of 0 to 10, preferably 0 to 5. However, m and n do not become 0 at the same time. Since mH ₂ O often represents a detachable aqueous phase that does not participate in the formation of a crystal lattice, m can take an integer or a non-integer value. Also, calcining this type of material can lead to a value of m of zero. General alumina hydrate can be produced by a known method such as hydrolysis of aluminum alkoxide and hydrolysis of sodium aluminate. R
osk et al. (Collect czech Chem
Commun, vol. 56, 1253-1262, 1991
Year) is the precipitation temperature, the solution p
H, aging time, reported to be affected by surfactant. Among alumina hydrates, pseudo-boehmite is described in literature (Rosek J al., Et., Applied
catalysis, Vol. 74, 29-36, 1991
It is generally known that there are cilia-like and non-ciliform shapes as described in US Pat. The alumina hydrate used in the present invention has a spindle shape having an average aspect ratio of 1 to 4. The average aspect ratio is calculated by dividing the major axis diameter of the particle by the minor axis diameter. The particle shape was measured by a method described below by observation with a transmission electron microscope.

The BET specific surface area, pore size distribution and pore volume of alumina hydrate, the pore size distribution and pore volume of the alumina hydrate and the ink receiving layer containing the alumina hydrate are determined by nitrogen adsorption and desorption. It can be obtained simultaneously by the separation method. The BET specific surface area of the non-oriented alumina hydrate used in the present invention is preferably in the range of 70 to 300 m ² / g. When the BET specific surface area is smaller than the lower limit of the above range, the pore size distribution may be shifted to the larger side and the dye in the ink may not be sufficiently adsorbed and fixed. In some cases, it is not possible to apply the Japanese product with good dispersibility and the pore size distribution cannot be adjusted.

The method for producing alumina hydrate used in the present invention can be, for example, a hydrolysis / peptization method of aluminum alkoxide or a hydrolysis / peptization method using aluminum nitrate and sodium aluminate. As shown in Examples described later, a spindle-shaped alumina hydrate having an average aspect ratio of 1 to 4 can be obtained by taking a two-stage crystal growth process, but the production method is not particularly limited to this method. Not necessarily. For example, after forming an alumina hydrogel slurry from hydrolysis of aluminum alkoxide or hydrolysis with aluminum nitrate and sodium aluminate, a powder of alumina hydrate is formed by a method such as spray drying, and then dispersed in an acid solution. Thereafter, it can be produced by adding sodium aluminate and growing the crystal again. When the crystal growth is accelerated, the shape anisotropy tends to be small and non-oriented.

The recording medium of the present invention is obtained by applying a coating liquid (dispersion liquid of alumina hydrate) containing the above-mentioned non-oriented alumina hydrate and a binder as a pigment on a base material to form an ink receiving layer. I do. The physical properties of the ink receiving layer are not determined only by the non-oriented alumina hydrate used, but also by the type and amount of the binder, the concentration, viscosity, dispersion state of the coating liquid, the coating device, the coating head, the coating head, and the like. In the present invention, it is necessary to adjust the manufacturing conditions to an optimum range in order to obtain the characteristics of the ink receiving layer, because the conditions vary depending on various manufacturing conditions such as the amount of work and drying conditions.

The pores of the ink receiving layer preferably have a maximum distribution of pore radii in the range of 30 to 200 °. When the maximum pore radius is larger than the upper limit of the above range, the adsorption and fixation of the dye in the ink is deteriorated, and the image is easily blurred, and when the radius is smaller than the lower limit, the ink absorbency is reduced. Beading is likely to occur.

The pores of the non-oriented alumina hydrate constituting the ink receiving layer also preferably have a maximum distribution of the pore radius in the range of 30 to 200 ° similarly to the ink receiving layer. The maximum pore radius of the ink receiving layer depends on the maximum pore radius of the alumina hydrate.

In the recording medium of the present invention, the binder that can be used in combination with the non-oriented alumina hydrate can be freely selected from water-soluble polymers. For example, polyvinyl alcohol or a modified product thereof, starch or a modified product thereof, gelatin or a modified product thereof, casein or a modified product thereof, gum arabic, carboxymethyl cellulose, hydroxyethyl cellulose,
Cellulose derivatives such as hydroxypropyl methylcellulose, SBR latex, NBR latex, conjugated diene copolymer latex such as methyl methacrylate-butadiene copolymer, functional group-modified polymer latex,
Preferred are vinyl copolymer latex such as ethylene-vinyl acetate copolymer, polyvinylpyrrolidone, maleic anhydride or a copolymer thereof, and acrylate copolymer. These binders can be used alone or in combination of two or more. The mixing ratio of the non-oriented alumina hydrate and the binder is 1: 1 to 30:
1, more preferably in the range of 5: 1 to 25: 1. When the amount of the binder is smaller than the above range, the mechanical strength of the ink receiving layer is insufficient, and cracking or powder dropping may occur. Absorption may decrease.

The alumina hydrate and the binder may include, if necessary, an alumina hydrate dispersant, a thickener, a pH adjuster,
A lubricant, a fluidity modifier, a surfactant, an antifoaming agent, a waterproofing agent, a release agent, a fluorescent brightener, an ultraviolet absorber, an antioxidant, and the like may be added.

As the base material of the recording medium of the present invention, papers such as appropriately sized paper, non-size paper, resin-coated paper using polyethylene and the like, sheet-like substances such as thermoplastic films, and cloths Can be used, and there is no particular limitation.

In order to obtain a recording medium having a texture such as a silver halide photograph, the basis weight is 120 g / m ² or more, and more preferably 150 to 1 g / m ^2.
A substrate composed of 80 g / m ² of fibrous material (eg, wood pulp) is preferred.

In the present invention, the ink receiving layer may have a multilayer structure. For example, a porous first ink receiving layer containing barium sulfate and a second ink receiving layer containing non-oriented alumina hydrate may be laminated from the substrate side.

It is preferable to use barium sulfate from which impurities are removed as much as possible in order to improve whiteness and light resistance. Furthermore, in order to improve the smoothness of the lower layer surface, the average particle diameter of barium sulfate is 0.4 μm
The range of 1.0 μm is preferable, and 0.4 μm to 0.8 μm
Is more preferable. When this range is less than 0.4 μm, whiteness, glossiness, solvent absorbability tends to decrease,
If it exceeds 1.0 μm, whiteness and glossiness will be affected.

It is preferable to use gelatin as a binder for binding barium sulfate. Because the refractive index of barium sulfate and gelatin is close,
The reflection at the interface is relatively small.

The kind of gelatin may be any of acid treatment, alkali treatment and the like. The amount of gelatin in preparing the coating solution is from 6 to 12 parts by weight based on 100 parts by weight of barium sulfate.
Parts by weight are preferred. Further, chromium sulfate, chromium alum, formalin, triazine and the like are generally used as a cross-linking agent for gelatin, but chromium alum is preferably used mainly for ease of handling. The amount of the crosslinking agent added is preferably 0.2 to 4 parts by weight based on 100 parts by weight of gelatin.

The coating amount of barium sulfate on the substrate is as follows.
The solid content of the coating liquid is 20 to 40 in order to sufficiently impart the solvent absorptivity of the ink and to provide the necessary smoothness.
g / m ² . Coating /
The drying method is not particularly limited, but it is preferable that the surface of the first ink-receiving layer be 87% or more in whiteness and the Bekk smoothness of the surface be 400 seconds or more as a finishing step by performing a surface smoothing treatment such as a super calender. .

If the smoothness is too high, the ink absorbency tends to decrease, so the smoothness is preferably set to 600 seconds or less.
More preferably, the time is set to 500 seconds or less.

As shown in FIG. 5, on the back surface of the substrate 1 (the surface opposite to the surface on which the ink receiving layer 2 is provided),
Release paper 4 is provided via an adhesive 3 such as a pressure-sensitive adhesive,
A sheet to which the recording medium of the present invention can be attached may be used. That is, by removing the release paper 4, the recording medium of the present invention can be attached to an appropriate place.

Further, in the present invention, a porous layer containing thermoplastic resin particles may be provided on the ink receiving layer as the outermost layer. By doing so, the applied ink is
Through the porous layer, the ink reaches the lower ink receiving layer, an image is formed thereon, and then the outermost layer is made nonporous, whereby a printed matter having a high image density and excellent weather resistance is obtained. Can be

Latex is preferred as the thermoplastic resin particles used for the outermost layer.

In the recording medium having an ink receiving layer according to the present invention, the method for forming the ink receiving layer on the substrate may be performed by using a dispersion solution containing the above-mentioned non-oriented alumina hydrate using a coating apparatus. A method of applying and drying on a material can be used. Blade coaters, air knife coaters, roll coaters, which are commonly used as coating methods,
Curtain coater, bar coater, gravure coater,
A coating technique using a spray device or the like can be employed. The coating amount of the dispersion is 0.5 to 60 g in terms of dry solid content.
/ M ² , more preferably 5 to 45 g / m ² . If necessary, the surface smoothness of the ink receiving layer can be improved by using a calender device after coating.

The ink jet recording method of the present invention uses the recording medium described above, and prints images, characters, and the like on the recording medium by flying and attaching fine droplets of ink. is there. Such an ink jet recording system may be either a bubble jet system or a piezo system. However, it is preferable to employ the bubble jet system from the viewpoint of enabling high-speed printing and high-definition printing. A water-based ink is preferable, and a dye or pigment can be used as a pigment.

When the recording medium of the present invention has an outermost layer, after forming an image by applying ink, the outermost layer is made nonporous (transparent) by heat treatment. By performing such treatment, weather resistance such as water resistance and light resistance becomes good, and gloss can be imparted to an image.

[0037]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.
The measurement of physical properties was performed by the following methods.

(1) A sample for measurement of BET specific surface area, pore diameter distribution, and pore volume was sufficiently heated and degassed and then measured by a nitrogen adsorption / desorption method (Omni Soap 360, manufactured by COULTER).

(2) Observation of shape of alumina hydrate (aspect ratio, particle shape) Powder of alumina hydrate is directly or dispersed in ion-exchanged water at a concentration of 1 to 2%, and a collodion film is formed from the solution. A sample for measurement was prepared by scooping with an applied copper mesh and removing excess water. When the measurement object is an ink receiving layer, the recording medium is 500 to 4000 with a microtome.
A thin section was formed as a sample for measurement. These samples were observed with a transmission electron microscope (H-manufactured by Hitachi, Ltd.).
800). The average aspect ratio was determined by dividing the major axis diameter of the particle by the minor axis diameter.

(3) Measurement of Restricted-Field Electron Diffraction Image and Variation of Diffraction Intensity A recording medium having an ink receiving layer formed on a substrate was formed into a thin section of 700 ± 100 ° by a microtome to obtain a sample for measurement. The limited area of the limited area diffraction is 200 mm in diameter.
The angle was set to 0 °, and 10 points at different cross sections were measured and averaged. Electron diffraction (H-800, manufactured by Hitachi, Ltd.) of the cross section of the ink receiving layer was measured, and the diffraction intensity of the diffraction image was transferred to an imaging plate (manufactured by Fuji Photo Film). The intensity distribution of the image was measured. The fluctuation value of the diffraction intensity was obtained by the above-mentioned equation (1).

(3) Printing Characteristics An ink jet head provided with 128 nozzles at a nozzle interval of 16 nozzles per 1 mm using an ink jet printer provided with four colors of Y, M, C, and Bk. Ink jet recording was performed using the ink, and the ink absorbency, image density, bleeding, and beading were evaluated.

Ink Absorptivity With respect to the inks having the following ink compositions, the ink absorbency of the ink on the surface of the recording medium after solid printing of each of Y, M, C, and Bk in single color and mixed color was examined by touching the recording portion with a finger. Was. 100% ink volume per unit area for single color printing
○ indicates that the ink did not adhere to the finger when the mixed ink amount was 300%, and 付 着 indicates that the ink adhered to the finger when the mixed ink amount was 300% but the ink did not adhere to the finger when the mixed ink amount was 200%. did.

Image Density Y, M, C, Bk
The image density of each of the solid printed images was evaluated using a Macbeth reflection densitometer RD-918.

Bleeding and beading The following ink composition 1 was evaluated for bleeding on the surface of a recording medium after solid printing of each of Y, M, C, and Bk inks in a single color and a mixed color. In addition, for each of the following two types of ink compositions, beading after solid printing of each of Y, M, C, and Bk in a single color or a mixed color was visually evaluated. If the ink amount in the single color printing is 100%, if the ink amount does not occur at the mixed ink amount of 300%, ○, it occurs at the mixed ink amount of 300%, but the mixed ink amount is 200%
If it did not occur in, it was rated as △.

The following ink compositions are on a weight basis.

(Ink Composition 1) Dye (Y, M, C or Bk below) 5 parts Ethylene glycol 10 parts Polyethylene glycol 10 parts Water 75 parts (Ink composition 2) Dye (Y, M, C or Bk below) 5 parts Ethylene glycol 15 parts Polyethylene glycol 10 parts Water 70 parts (dye) Y: C.I. I. Direct Yellow 86 M: C.I. I. Acid Red 35 C: C.I. I. Direct Blue 199 Bk: C.I. I. Food black 2

[Examples 1 to 3] US Patent Specification No. 424
Aluminum octoxide was synthesized and hydrolyzed by the method described in Nos. 2271 and 4202870 to produce an alumina slurry. Water was added to this alumina slurry until the alumina hydrate solid content became 5%. Next, after raising the temperature to 80 ° C. and performing an aging reaction for 10 hours, this colloidal sol was spray-dried to obtain an alumina hydrate. Furthermore,
This alumina hydrate was mixed and dispersed in ion-exchanged water, adjusted to pH 5 with nitric acid, heated to 95 ° C., and adjusted to pH 10 by adding sodium aluminate. The aging time was 5 hours (Example 1), 10 hours (Example 2), and 15 hours (Example 3) to obtain the colloidal sols of Examples 1 to 3. After desalting the colloidal sol, acetic acid was added to peptize. An alumina hydrate obtained by drying the colloidal sol was measured by X-ray diffraction and found to be pseudo-boehmite. When the alumina hydrate was observed with a transmission electron microscope, it was found to be spindle-shaped. The physical properties of each alumina hydrate were measured by the above methods, and the results are shown in Table 1.

Polyvinyl alcohol PVA117 (trade name, manufactured by Kuraray Co., Ltd.) was dissolved in ion-exchanged water and 10% by weight.
Was obtained. The colloidal sol of the above three types of alumina hydrate was concentrated to obtain a 15% by weight solution. The colloidal sol of the alumina hydrate and the polyvinyl alcohol solution were mixed and stirred so that the weight ratio of the solid content of the alumina hydrate to the solid content of the polyvinyl alcohol was 10: 1 to obtain a dispersion. The above dispersion was treated with a PET having a thickness of 100 μm.
The film was die-coated on a film (trade name: Lumirror, manufactured by Toray Industries, Inc.) to obtain an ink-receiving layer having a dry thickness of about 40 μm. FIG.
Is a drawing-substitute photograph (transmission electron microscope: 100,000-fold magnification) showing a cross section of the ink receiving layer, and it can be seen that spindle-shaped alumina hydrate is contained in the ink receiving layer without orientation. For further clarification, the electron diffraction of the cross section was measured by the above method. The result is shown in FIG. 2 as a drawing substitute photograph. The physical properties of the ink receiving layer were measured by the above methods. Table 2 summarizes the results.

Example 4 A colloidal sol of alumina hydrate was synthesized by a hydrolysis method using an aqueous solution of aluminum nitrate and an aqueous solution of sodium aluminate. In the synthesis, the concentration and amount of each material were adjusted so that the solid content of alumina hydrate was 5% and the pH after the addition of sodium aluminate was 9, and the reaction temperature was aged at 90 ° C. for 10 hours. After the obtained colloidal sol was desalted, it was spray-dried to obtain an alumina hydrate. Further, the alumina hydrate was mixed and dispersed in ion-exchanged water, adjusted to pH 5 with nitric acid, heated to 95 ° C., and added with sodium aluminate to adjust the pH to 1.
It was adjusted to 0 and the aging time was 15 hours to obtain a colloidal sol. After desalting the colloidal sol, acetic acid was added to peptize. When the alumina hydrate obtained by drying the colloidal sol was measured by X-ray diffraction,
It was pseudo boehmite. Observation of the alumina hydrate with a transmission electron microscope revealed that the alumina hydrate had a spindle shape. The physical properties of this alumina hydrate were measured in the same manner as above, and the results are shown in Table 1. In addition, an ink receiving layer was formed in the same manner as in Examples 1 to 3, and electron beam diffraction and physical properties of the ink receiving layer were measured. Table 2 shows the results.

Example 5 As in Example 4, a colloidal sol of alumina hydrate was synthesized by a hydrolysis method using an aqueous solution of aluminum nitrate and an aqueous solution of sodium aluminate. First, an aqueous solution of sodium aluminate was added to an aqueous solution of aluminum nitrate so as to have a pH of 5, to precipitate crystals of alumina hydrate, and the mixture was allowed to stand at a liquid temperature of 30 ° C for 2 hours with stirring. Next, sodium aluminate was added again to adjust the pH to 9, followed by aging at a liquid temperature of 90 ° C. for 10 hours. The solid content of the synthesized alumina hydrate was adjusted to 5%. From the colloidal sol thus obtained, alumina hydrate was obtained through the same steps as in Example 4.

The physical properties of this alumina hydrate were measured in the same manner as in Example 1, and the results are shown in Table 1. Further, a recording medium of the present invention was prepared in the same manner as in Example 1 using the obtained alumina hydrate, and electron beam diffraction and physical properties of the ink receiving layer were measured. The results are shown in Table 2.

Example 6 The same procedure as in Example 5 was carried out except that the standing time after precipitation of the alumina hydrate having a pH of 5 was 4 hours.
Otherwise in the same manner as in Example 5, an alumina hydrate was obtained.

The physical properties of this alumina hydrate were measured in the same manner as in Example 1, and the results are shown in Table 1. Further, a recording medium of the present invention was prepared in the same manner as in Example 1 using the obtained alumina hydrate, and electron beam diffraction and physical properties of the ink receiving layer were measured. The results are shown in Table 2.

Example 7 As a base material, a P having a thickness of 75 μm was used.
Using ET film, dry thickness of ink receiving layer is about 30μ
A recording medium was prepared in the same manner as in Example 1 except that m was used.

Next, a pressure-sensitive adhesive for pressure-sensitive adhesive labels using an acrylate-based copolymer as a base polymer was applied to release paper to a thickness of about 50 μm using a blade coater. This release paper was adhered to the back surface of the PET film of the recording medium prepared earlier to prepare a recording sheet. The recording medium thus obtained could be attached to an appropriate place by peeling off the release paper.

Comparative Example 1 Alumina hydrate (sol) having a hairy bundle (ciliform) structure was synthesized by the hydrolysis and peptization method of aluminum isopropoxide. An ink receiving layer was formed in the same manner as in Example 1 to prepare a recording medium. The cross section of the ink receiving layer was observed with a transmission electron microscope, electron beam diffraction and physical properties were measured. Figure 3 shows a transmission electron micrograph.
FIG. 4 shows an electron beam diffraction image as a drawing substitute photograph. The physical properties of the alumina hydrate and the physical properties of the ink receiving layer are summarized in Tables 1 and 2. Example 1 and Comparative Example 1
For the recording medium of No. 1, the ink absorbency was measured by a Bristow tester manufactured by Toyo Seiki Seisaku-sho, Ltd. FIG. 6 shows the results. It is clear from this that the ink absorption rate is higher when non-oriented alumina hydrate is used as the ink receiving layer than when oriented alumina hydrate is used.

[0057]

[Table 1]

[0058]

[Table 2]

Example 8 100 parts by weight of barium sulfate having an average particle size of 0.6 μm formed by reacting sodium sulfate and barium chloride, 10 parts by weight of gelatin, 3 parts by weight of polyethylene glycol, 0.4 parts by weight of chromium alum Was blended to obtain a coating liquid. This coating solution was weighed to 150 g / m ² ,
Coating base paper having a Steckigt sizing degree of 200 seconds and a Beck smoothness of 340 seconds is applied by a die coater to a dry thickness of 20 μm, and then subjected to a super calender treatment to obtain a recording medium having a surface smoothness of 400 seconds. Was.

US Pat. No. 4,242,271, 42
Aluminum octoxide was synthesized and hydrolyzed by the method described in No. 02870 to produce an alumina slurry. This alumina slurry is mixed with alumina hydrate having a solid content of 5%.
% Water was added. Next, after raising the temperature to 80 ° C. and performing an aging reaction for 10 hours, this colloidal sol was spray-dried to obtain an alumina hydrate. Further, this alumina hydrate is mixed and dispersed in ion-exchanged water, and the pH is adjusted with nitric acid.
After adjusting the temperature to 5, the temperature was raised to 95 ° C., the pH was adjusted to 10 by adding sodium aluminate, and the mixture was aged for 10 hours to obtain a colloidal sol. After the colloidal sol was desalted, acetic acid was added to pulverize it, and the alumina hydrate obtained by drying was measured by X-ray diffraction to be pseudo-boehmite. Observation of the alumina hydrate with a transmission electron microscope revealed that the alumina hydrate had a spindle shape.

This coating solution was applied on the recording medium using a bar coater so that the coating amount after drying was 20 g / m ² , and dried at 100 ° C. for 10 minutes. Then, a baking treatment was performed at 150 ° C. for 2 minutes to form a porous layer of alumina hydrate, thereby obtaining a recording medium of the present invention.

Table 3 shows the results of printing on this recording medium and evaluating each item.

In the table, the smoothness was measured using a Bekk smoothness meter (manufactured by Yoshimitsu Seiki Co., Ltd.) and the range "1 cc" for a highly smooth sample.
Is the value obtained by multiplying the measured value by 10 times. The whiteness is a value measured using a Hunter Reflectometer (manufactured by Toyo Seiki Seisaku-sho, Ltd.) using a blue filter. The gloss is a value obtained by measuring 75 ° gloss using a digital variable-angle gloss meter (manufactured by Suga Test Instruments Co., Ltd.) based on JIS-P-8142.

Example 9 The base paper and the barium sulfate coating solution used in Example 8 were dried to a thickness of 13
After coating to a thickness of μm, a super calendar treatment was performed to obtain a recording medium having a surface smoothness of 320 seconds.

After drying the coating solution containing pseudo-boehmite used in Example 8 on this medium using a bar coater, 20 g was applied.
/ M ² , dried open at 100 ° C. for 10 minutes, and then baked at 150 ° C. for 2 minutes to obtain a recording medium of the present invention.

This recording medium was evaluated in the same manner as in Example 8. Table 3 shows the results.

[0067]

[Table 3]

Example 10 A latex (average particle diameter: 0. 1) was formed on the ink receiving layer of the recording medium prepared in Example 1.
2 μm) The solution was applied using a bar coater to a dry film thickness of about 5 μm, and oven dried at 60 ° C. for 10 minutes. When an image was recorded on the obtained recording medium with an ink jet printer, the ink was transmitted through the latex layer, an image was recorded on the ink receiving layer, and an image of the latex layer with a white veil was observed. At 130 ° C, 1
When heated in an oven for 0 minutes, the latex layer on the outermost surface melted to form a transparent film, and an image with high gloss and no ozone fading (ozone resistance) could be obtained.

[0069]

As described above, in the recording medium of the present invention, the alumina hydrate has a diffraction intensity variation of 5% in the ink receiving layer.
It exists non-oriented as follows. For this reason, compared with a recording medium using a hair bundle (ciliform) alumina hydrate having orientation, the resistance to ink penetration is small and the ink absorption speed is high. Thereby, beading can be prevented from occurring, and excellent print quality can be realized.

[Brief description of the drawings]

FIG. 1 is a transmission electron micrograph of a cross section of an ink receiving layer using the non-oriented alumina hydrate of the present invention, showing the shape of the non-oriented alumina hydrate and the arrangement state in the ink receiving layer. It is a drawing substitute photograph.

FIG. 2 is a drawing substitute photograph showing an electron diffraction image of a cross section of an ink receiving layer using the non-oriented alumina hydrate of the present invention.

FIG. 3 is a transmission electron micrograph of a cross section of an ink receiving layer using the oriented alumina hydrate of Comparative Example 1, showing a shape of the oriented alumina hydrate and an arrangement state in the ink receiving layer. It is a substitute photograph.

FIG. 4 is a drawing substitute photograph showing an electron diffraction image of a cross section of an ink receiving layer using the oriented alumina hydrate of Comparative Example 1.

FIG. 5 is a recording medium of the present invention in which release paper is provided on the back surface of a base material.

FIG. 6 is a graph showing a result obtained by performing a measurement with a Bristow tester on the recording media of Example 1 and Comparative Example 1.

 ──────────────────────────────────────────────────続 き Continued on the front page (31) Priority claim number Japanese Patent Application No. 9-101760 (32) Priority date Heisei 9 (1997) April 18 (33) Priority claim country Japan (JP) (72) Inventor Ako Omata 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc.

Claims (9)

[Claims] 1. A recording medium having an ink receiving layer containing alumina hydrate on a base material, wherein the alumina hydrate exists in a non-oriented manner in the ink receiving layer, and A recording medium characterized in that a diffraction intensity fluctuation value δ of a diffraction image when irradiated with an electron beam is 5% or less. 2. The recording medium according to claim 1, wherein the alumina hydrate has a spindle shape having an average aspect ratio of 1 or more and 4 or less. 3. The recording medium according to claim 1, wherein the maximum of the pore radius distribution of the ink receiving layer measured by a nitrogen adsorption / desorption method is 30 ° or more and 200 ° or less. 4. A BET specific surface area of the alumina hydrate as measured by the nitrogen adsorption desorption method is 70m ² / g or more 300 meters ²
2 / g or less. 5. The ink receiving layer is formed by laminating a porous first ink receiving layer containing barium sulfate and a second ink receiving layer containing non-oriented alumina hydrate. 2. The recording medium according to 1. 6. The whiteness of the first ink receiving layer is 87%.
The recording medium according to claim 5, wherein the Bekk smoothness is 400 seconds or more. 7. The recording medium according to claim 6, wherein the Beck smoothness is 600 seconds or less. 8. The recording medium according to claim 1, wherein release paper is provided on the back surface of said base material via an adhesive. 9. An ink jet recording method, characterized by flying ink droplets onto the recording medium according to claim 1, 5 or 8.