JP2010077276A - Ink for use in inkjet recording apparatus - Google Patents

Abstract

An object of the present invention is to efficiently produce a wide variety and a small amount of color ink for an ink jet recording apparatus.
A base ink comprising a resin, a color material, and a solvent and a color material having a color tone different from that of the base ink and a toning agent comprising a solvent are mixed.
[Selection] Figure 2

Description

  The present invention relates to an ink for an ink jet recording apparatus.

  The ink jet recording apparatus is an apparatus that forms characters by making ink particles and attaching them to a printed matter. Among them, the continuous ink jet recording apparatus needs to have conductivity in order to charge ink particles. The ink is composed of a resin, a solvent, an additive, and a color material. As a method for imparting conductivity to the ink, a salt that dissolves in the solvent may be used (hereinafter referred to as “conductive agent”).

Here, a technique relating to the base resin for toning is disclosed in Patent Document 1, for example. On the other hand, in the ink jet recording apparatus, there is a demand for various color inks according to customer needs. Color materials used for color inks include dyes and pigments. In the case of pigment ink, a dispersant or resin may be used to disperse the pigment in the ink. The dispersant is blended for the purpose of preventing aggregation of pigments by adsorbing to the pigment, but most of the dispersants are surfactants. The surfactant is a substance having a hydrophilic group and a hydrophobic group. When the hydrophilic group is adsorbed on the hydrophilic pigment surface, the pigment surface becomes hydrophobic and can be uniformly dispersed in the hydrophobic solvent.
When the solvent is a polar solvent such as MEK, a polar group may be added to facilitate dispersion. In addition, when a dye is used, the dye itself may have a polar group when a metal complex dye is used due to solubility and light resistance.
When a pigment is used as the coloring material, a conductive agent that does not inhibit the dispersion has been selected because the conductive agent neutralizes the potential of the dispersant in order to stably disperse the pigment on the solution.

In addition, when a dye is used as the coloring material, the conductive agent becomes an ion in the ink, so that the ion is adsorbed on the polar group of the dye, so that the solubility of the coloring material or the conductive agent is lowered, leading to precipitation. Therefore, a stable conductive agent was selected for each dye.
JP 07-41727 A

Therefore, in order to manufacture various color inks, it is necessary to evaluate the combination of the color material and the conductive agent used for the color ink. In addition, when there are various local demands such as color-coding by product according to the needs of color inks, it is necessary to prepare an ink jet recording apparatus for each type of ink. Furthermore, since the demand for color ink is small compared to standard colors such as black, it is necessary to deal with small-scale production.
An object of the present invention is to efficiently produce a wide variety and a small amount of color ink for an ink jet recording apparatus.

  Another object of the present invention is to propose that color inks can be used immediately upon customer request.

  In order to solve the above-mentioned problems, according to the present invention, in the ink for an ink jet recording apparatus, a base ink composed of a resin, a color material, and a solvent is mixed with a color material having a color tone different from that of the base ink and a color toner composed of a solvent. The configuration is as follows.

By arranging a plurality of colorants for one type of base ink, a small amount of color ink can be produced.
Further, by arranging the base ink and the colorant separately, the color ink can be supplied immediately upon customer request.

Hereinafter, embodiments of the present invention will be described.

Embodiments of the present invention will be described below.
The resin used for the base ink for toning of the ink jet recording apparatus is not particularly specified as long as it is a thermoplastic resin from the viewpoint of storage stability. A polar resin is desirable. Moreover, vinyl acetate, styrene, etc. may be copolymerized with these resins from the viewpoints of adhesion to the counterpart substrate and ink particle formation stability. In general, the molecular weight is preferably about 8000 to 45000. This is because the strength of the coating film is lowered when it is 8000 or less, and it is difficult to stably produce ink particles when it is 45,000 or more.

The acid value is desirably 80 to 200 (KOHmg / g) when a pigment is used as a coloring material. If the acid value is 80 or less, the dispersion stability is impaired, and if it is 200 or more, the physical properties of the coating film are lowered. However, this does not apply when dyes are used as the coloring material.
The solvent is not particularly specified as long as it can dissolve the above-mentioned resin, but is preferably a ketone system having fast drying properties and good solubility.
Additives can be used for the base ink to improve printing smoothness and transferability. The additive is preferably a silicone type or a fluorine type.
As the conductive agent, an organic salt or an inorganic salt can be used, but an organic salt is preferable from the viewpoint of coating film performance. Any organic salt that can be dissolved in a solvent can be used, but ammonium salts and phosphonium salts are preferred in terms of conductivity and solubility.
It is desirable to use a solvent compatible with the resin as the dye used for the toning agent. Dyes and pigments can be used as the color material, but dyes can be easily manufactured from the viewpoint of dissolution stability during mixing. The dye to be used is not limited as long as it is compatible with the above resin, but a chromium complex dye is preferable from the viewpoint of light resistance. For example, solvent black 27 and solvent black 29 can be used for black, and solvent yellow 79 and solvent yellow 81 can be used for yellow.
In the case of using a pigment for the color material, titanium oxide, organic pigment, carbon black, and the like can be used. When it is 150 μm or less, dispersion stability becomes difficult, and when it is 500 nm or more, the sedimentation rate and the frequency of nozzle clogging increase.
The base ink and toning agent of the present invention are produced by mixing, stirring and filtering the above substances.
Manufacture and store base ink and toning agent separately. The customer requires the desired color and density. The factory mixes the base ink and toning agent as required. The prepared solution is filtered, filled into a container and shipped. The manufacturer can assort a wide variety of color inks without individually stocking the color inks.

Next, the usage method in a customer is demonstrated.
The base ink and the toning agent are filled in separate containers. Leave a space for the toning agent in the base ink container. By setting the space to the maximum amount of toning agent input, work errors such as excessive insertion are prevented. Add the toning agent to the base ink space and mix. The amount of the toning agent can be adjusted according to the required concentration according to the sample.

  Next, the automation means of the present invention is provided in order to save the trouble of mixing at the time of toning.

  FIG. 1 is a functional block diagram of an ink jet recording apparatus according to the present invention. The nozzle 1 is pressurized by the pump 9 and ejects the ink regulated by the pressure regulating valve 8 to separate the tip end portion of the ink column 2 to generate ink particles 3 toward the printed matter 4. Let it fly. The charging electrode 5 is installed so as to surround the region where the ink column 2 is separated and the ink particles 3 are generated, and a charging voltage is applied to charge the tip of the ink column 2. The charge amount at the tip of the ink column 2 is a value proportional to the charging voltage. The ink particles 3 formed by separating the tip of the charged ink column 2 become ink particles 3 that retain the charge amount in the state of the ink column 2, and eventually the ink particle 3 has a charge amount proportional to the charging voltage. It will be charged. The deflection electrode 6 is installed so as to oppose the flight path of the ink particles 3, and a deflection electric field is applied to the flight path by being applied to the deflection electrode 6 from a deflection power source. The ink particles 3 flying in the deflection electric field are deflected according to the charge amount. The gutter 7 is placed so as to block the flight path of the ink particles 3 that go straight without being charged, and capture and collect the ink particles 3 that are not used for printing.

The ink container 11 is a container for containing the base ink, and is mixed with the toning agent. The mixer 18 is installed in the ink container 11. The toning agent container 10 is a container for containing the toning agent. The operation panel 17 is a touch input display panel including a dot matrix display type liquid crystal display panel that functions as a display device and a transparent touch input switch that functions as an input device superimposed on the surface. The microcomputer 19 constituting the main controller 14 includes a CPU 15 and a memory 16, displays a control processing menu on the liquid crystal display panel of the operation panel 17, and executes various control processes according to instructions input from the touch input switch. The control processing result is displayed on the liquid crystal panel.
FIG. 2 is a flowchart of control processing executed by the microcomputer 19. This control processing is executed according to a control processing program stored in the memory.
In step 100, the power is turned on and an ink mixing screen is selected from the menu screen. In step 101, a density value is selected by touch input on the operation panel 17, and mixing is started. Next, in step 102, the CPU 15 calls the pump driving time stored in advance in the memory 16 from the concentration value. The CPU 15 turns on the pump drive device during the time called in step 3. The pump 9a is driven, and a predetermined amount of the toning agent in the toning agent container 10 is charged.
In step 103, the CPU 15 drives the mixer driving device 13 for a predetermined time. The mixer 18 stirs the ink container 11. After a certain time has elapsed, the CPU 15 turns off the mixer driving device 13.

  As described above, according to the invention according to the present embodiment, it is possible to efficiently produce a wide variety and a small amount of color ink for an inkjet recording apparatus.

1 is a functional block diagram of an ink jet recording apparatus according to the present invention. 3 is a flowchart of control processing executed by a microcomputer that constitutes a main control device of the ink jet recording apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Nozzle, 2 ... Ink column, 3 ... Ink particle, 4 ... Printed matter, 5 ... Charge electrode, 6 ... Deflection electrode, 7 ... Gutter, 8 ... Pressure regulating valve, 9 ... Pump, 10 ... Toning agent container, 11 ... Ink container, 12 ... Pump drive device, 13 ... Mixer drive device, 14 ... Main control device, 15 ... CPU, 16 ... Memory, 17 ... Operation panel, 18 ... Mixer

Claims (6)

  An ink for an ink jet recording apparatus, comprising: a base ink composed of a resin, a color material, and a solvent; a color material having a color tone different from that of the base ink; and a color toner composed of a solvent.   The ink for an ink jet recording apparatus according to claim 1, wherein the resin is a thermoplastic resin and a highly polar resin.   The ink for an ink jet recording apparatus according to claim 1, wherein the solvent used in the base ink is a ketone.   The ink for an ink jet recording apparatus according to claim 1, wherein the base ink contains a silicone-based or fluorine-based additive.   The ink for an ink jet recording apparatus according to claim 1, wherein the color material of the toning material is a chromium complex dye.   The ink for an ink jet recording apparatus according to claim 1, wherein the colorant of the toning agent is at least one of titanium oxide, an organic pigment, or carbon black.

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