JP2002283707A - Printing medium for ink jet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent image quality of an ink jet printer from being deteriorated with time due to use of oil-based pigment ink. SOLUTION: A material, which swells by absorbing an oil-based solvent, is mixed into a coated layer, and the absorbed solvent is fixed to prevent movement with time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to the structure and function of a print medium for obtaining a print image by absorbing and fixing ink ejected from an ink jet printer.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional print medium structure.
FIG. 5 is a diagram showing a cross-sectional structure of a general ink jet print medium called a penetration type or a void type as an example of a conventional technique. As the substrate 1 of the media, a paper substrate made of general pulp, a resin film, or the like is used. On the substrate 1, mainly an inorganic pigment such as amorphous silica having a size of about 10 μ or less, which itself is porous, polyvinyl alcohol or latex serving as an adhesive for connecting and fixing the inorganic pigment, Is stirred with water as a solvent to formulate a coating agent, a coating agent comprising a dispersing agent for uniformly dispersing the filler 3 comprising an inorganic pigment such as silica is uniformly applied, and then a drying step is performed. By removing water as a solvent component, a structure as shown in FIG. 5 is obtained.

The oil-based pigment ink droplets landed on the surface of the ink absorbing layer 2 penetrate in the depth direction while passing through the flow path formed between the inorganic pigment fillers 3 and the pores of the inorganic pigment itself. At this time, the colorant pigment 4 contained in the ink droplet is caught by the structure and fixed, thereby fixing the ink. In a state where the ink is fixed, the oily solvent 5 is held as it is in the void portion formed by laminating the amorphous silica,
The retained oily solvent is in a state of being adjacent to a space around the solvent which is not filled with the solvent.

As a development of the infiltration type, there is Pictorico of Asahi Glass Co., Ltd. which secures the smoothness of the coated surface by orienting a flat plate material in a coating base material.

FIG. 6 is a view showing the structure of a conventional ink jet print medium called a swelling type.
It has a structure in which an ink absorbing layer 2 in which a binder having an affinity for an ink solvent such as gelatin or polyvinyl alcohol is applied to a substrate 1 of paper or a resin film is laminated.

The oil-based pigment ink droplets landed on the surface of the coat layer 2 swell the coat surface with the solvent, whereby the ink itself is taken into the coat layer 2 together with the colorant pigment 4. After that, the ink is fixed in a state where the colorant pigment 4 is taken into the inside of the coat layer by the solvent being naturally dried.

[0007]

However, when an oil-based pigment ink is to be fixed on a print medium formed by a conventional method, there are the following problems.

In the case of an absorption type coat layer structure made of a material such as amorphous silica, an oily solvent which does not dry naturally loses fluidity in a state where a space where the ink solvent is not filled exists near the ink solvent. It remains in the flow path three-dimensionally formed by the laminated structure of amorphous silica without being provided. This solvent permeates and moves over time into the voids that are not filled with the surrounding solvent. By moving pigments dispersed in the solvent and pigments separated from the solvent and remaining near the media surface with this movement, the print density and hue change over time, and the image quality deteriorates over time. I do.

Further, even in the initial state, the colorant pigment tends to sink into the lower layer of the ink demand layer due to the large ink passage space,
The print density and color development were not sufficient.

Further, in the case of a swelling type using a binder having an affinity for a solvent as a coating agent, an oily solvent which does not dry and evaporate naturally is not suitable for ordinary use since the coating layer is always in a dissolved state. As described above, problems are pointed out in the ink jet printer using the oil-based pigment ink in the fixing property of the ink and in securing the print quality over time.

[0011]

According to the present invention, there is provided an ink-jet print medium in which a conventional penetrating type and a swelling type are combined, ink is absorbed in an ink flow path, and swelled by an ink solvent absorbed in an ink absorbing layer. The ink solvent and the pigment are completely fixed in the ink absorbing layer by eliminating the fluidity of the ink solvent and eliminating the ink flow path itself, thereby preventing the image deterioration with time.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing an example of an embodiment of the present invention, and shows a structure in a depth direction of a coat layer.

In this embodiment, the ink jet medium has an ink absorbing layer 2 applied to a base material 1 of the medium.
The ink absorbing layer 2 is formed by laminating a filler 3 bonded by a binder in order to secure a void serving as an ink flow path, but this configuration is the same as that of a conventional permeation type medium. The present invention is characterized by the filler 3 constituting the ink absorbing layer 2.

On the media substrate 1 made of pulp paper, resin film, or a composite thereof, a material obtained by swelling with an ink solvent is reduced to a diameter of about 5 to 10 μm, or an inorganic pigment such as silica is used as the swelling material. A coating agent having a filler 3 as a main component is formed into an aqueous coating agent, applied and dried to form an ink absorbing layer 2
To form In the figure, all the fillers 3 are represented by images of spherical diameters of the same size for convenience, but actually have variations in size and shape. The material swelling with the oily pigment used for the filler 3 reacts with the oily solvent of the oily pigment ink to be used, such as butyl rubber, rubber such as urethane, or resin such as vinyl. By using a material that does not react with water, conventional water-based coating is possible. Also,
At this time, the swelling reaction rate can be controlled by selecting a material that reacts with the oily solvent according to the type of the oily solvent used.

When the ink is dropped on the ink jet print medium formed as shown in FIG. 1, the oil-based pigment ink penetrating into the print medium as shown in FIG. Similarly, the colorant pigment 4 dispersed in the oil-based pigment ink is
Is absorbed and absorbed along the gap.

After this initial penetration, the filler 3 made of a material that reacts and swells with the ink solvent as shown in FIG. 3 gradually absorbs and swells the surrounding ink solvent, and completely takes in the solvent. At this time, the filler 3 increases in volume due to swelling and becomes the swollen filler 8, which blocks the ink flow path between the fillers. Due to this phenomenon, the coloring agent pigment 4 remaining strained in the ink flow path is caught and loses the degree of freedom of movement, and the fixing is completed. In addition, the oily solvent 5 which causes deterioration of print quality over time is also absorbed by the filler 3 and is fixed by losing the flow path, so that deterioration over time can be prevented. At this time, by selecting the material to be used as the swelling agent and blending the conventional filler that does not swell with the swelling filler, it is possible to variously adjust the reduction amount of the ink flow path void and the swelling reaction rate It is.

FIG. 4 shows an example in which the internal structure of the ink absorbing layer 2 is subdivided. In the ink absorbing layer constructed as in the above example, the same layer of a filler that does not swell with an oily solvent is used. This is an example in which the information is provided. The ink absorbing layer 2 is divided into a pigment holding layer 6 and a solvent absorbing layer 7 in order to realize the printing density and the coloring property by holding the pigment on the media surface layer more. In the same configuration as in Example 2, a fine inorganic pigment layer is provided on the upper layer, and the flow path is made narrower than the pigment diameter so that only the colorant pigment 4 is scraped off and the oily solvent 5 is removed.
Only has a function of feeding only the solvent holding layer 7 below. With this configuration, the colorant pigment 4 is held near the surface of the medium, and the print density and the color developability are improved. In the lower layer, the filler 3 of the solvent holding layer 7 absorbs the oily solvent 5 and changes to the swelling filler 8 to fix the oily solvent. Further, in this example, since no swelling material is used as a filler for the pigment holding layer 6 on the media surface, the media surface is always dried and maintained in a state of good workability. Although the phenomenon of this example is the same as that of the conventional absorption type medium from the appearance, the fixing by swelling is performed inside the ink absorption layer 2. The pigment holding layer 6 is finer than the particle diameter of about 5 to 10 μm used for the solvent holding layer 7,
It can be formed by using a material such as silica or alumina having a diameter of several hundred nanometers.

Also in this example, it goes without saying that the amount of change in the void and the reaction rate can be adjusted by selecting the swelling material and the mixing ratio.

It is also conceivable to add a material that reacts with an oily solvent to a binder used for bonding the filler of the ink absorbing layer. Conventionally, polyvinyl alcohol or latex is used as the binder.In this case, it is possible to change the gap between the fillers by using a material that swells with an oily solvent in the binder composed of the polyvinyl alcohol or latex. Further, it is also possible to provide a swelling function for both the filler and the binder.

[0020]

As described above, according to the present invention,
By using a material that reacts and swells with the solvent of the oil-based pigment ink as a filler to form the ink absorption flow path of the inkjet media, when the ink lands on the media, it instantly resembles the conventional absorption type media. The ink can be absorbed, and thereafter, the ink can be completely fixed by the swelling action inside, so that the deterioration of the print quality with time can be suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of an inkjet print medium to which the present invention is applied.

FIG. 2 is a diagram illustrating a state at the time when ink is absorbed by a medium of the present invention.

FIG. 3 is a diagram showing a state at the time when ink is absorbed by the medium of the present invention and the reaction is completed.

FIG. 4 is a diagram showing an example of a structure to which the present invention is applied.

FIG. 5 is a view showing a structure of a permeation type coat layer according to a conventional technique.

FIG. 6 is a view showing a structure of a swelling type coat layer according to a conventional technique.

[Explanation of symbols]

 1 Media substrate 2 Ink absorbing layer 3 Ink absorbing layer filler 4 Colorant pigment 5 Oily solvent 6 Pigment fixing layer 7 Solvent fixing layer 8 Swelled filler

Claims (4)

[Claims] 1. A printing medium used in an ink jet printer for ejecting an ink in which a colorant pigment is dispersed in an oily solvent from an ink head and receiving and fixing the ejected ink droplets to obtain a printing result, wherein the ink absorbs the ink. A printing medium for an ink jet printer, characterized in that a filler for forming an ink flow path of an ink absorbing layer to be formed is made of a material which swells with an ink oil solvent. 2. The print medium for an ink jet printer according to claim 1, wherein the constituent material of the ink absorbing layer is made of a porous pigment coated with a material that swells with an ink oily solvent. 3. The printing medium for an ink jet printer according to claim 1, wherein the constituent material of the ink absorbing layer is formed by laminating a material that swells with an ink oily solvent and a material that does not swell with an ink solvent. . 4. The ink absorbing layer is formed by laminating a porous pigment coated with a material swelling with an ink oily solvent and a porous pigment not coating a material swelling with an ink solvent. A print medium for an ink jet printer according to claim 1.