JP2003026962A - Ink jet ink, ink jet recording method, and ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet ink which can be fixed without causing blur even on paper used in running on, giving an image with a good color development, and can form an image while suppressing jam due to cockling; and a method and apparatus for ink jet recording using the ink. SOLUTION: This ink contains a recording agent, a liquid medium for dissolving or dispersing the agent, and a compound capable of increasing liquid viscosity in the temperature range of 30-70 deg.C and is characterized in that, when the ink adheres to a heated recording medium, the viscosity of the ink increases.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an inkjet ink, an inkjet recording method, and an inkjet recording apparatus.

[0002]

2. Description of the Related Art Conventionally, an ink jet image forming method has been required to have a special paper as the image quality is improved, but in recent years, it has become more important as an ink jet image forming method. As a color for non-coated paper (generally referred to as plain paper) such as electrophotographic paper, report paper, notebook, notepaper, bond paper, and continuous slip paper that are commonly used in offices and homes There is a demand for an image-recording ink capable of performing high-definition full-color recording that is excellent in bleeding and without blurring, and an image forming method, and many proposals have been made to achieve such an object.

For example, JP-A-55-29546 discloses that
A method is disclosed in which a specific surfactant is added to the ink to lower the surface tension and enhance the ink permeability into the inside of the paper. Further, JP-A-55-57862 discloses a method in which a strongly basic substance is added to ink to chemically dissolve a paper sizing agent or a pulp material to control the spread and absorption of dots. Further, in JP-A-58-13675, polyvinylpyrrolidone having a molecular weight of 40,000 or more is added to the ink, or in JP-A-3-172362, a specific microemulsion is added. A method of controlling dot spread and absorbency is disclosed.

Also, US Pat. Nos. 3,653,932, 3,715,219, and 4,390,369,
No. 4,490,731 discloses solid-liquid phase change ink, that is, ink that is solid at room temperature but becomes liquid at a certain temperature or higher. This type of phase change ink, after being ejected as a liquid, collides with the recording material and immediately solidifies on the surface of the recording material.

Further, as an example of using a gel-sol transition ink, an ink which is in a gel state at room temperature, but which transitions to a sol state by heating is disclosed in JP-A-62-18137.
No. 2, JP-A-1-272623 and the like.
Similar to the solid-liquid phase change ink, all of these are intended to suppress ink bleeding by returning to a gel state after an ink droplet has landed on a recording material.

However, the above-mentioned prior art has the following problems. The method of increasing the penetrability of the ink into the paper by adding a surfactant improves the fixability, but has a problem that the coloring agent deteriorates because the recording agent also penetrates deeply into the paper. The method of adding a strong base substance to the ink causes bleeding and insufficient fixability on paper using a certain sizing agent, for example, neutral paper, and also has a problem in terms of human safety. . Further, adding a polymer or a certain kind of emulsion to the ink does not provide a sufficient effect in a region where the recording density of the ink is high as in full color recording. In addition, in the case of solid-liquid phase change type ink, since the ink must be liquefied during operation, not only the burden on the device such as temperature control of the ink supply system becomes heavy, but also the printed matter is exposed to extremely high temperature during storage. In the case of being exposed to the bottom, there is a problem that the ink is redissolved and the printed matter is destroyed.
The sol-gel type ink is not easy to handle like the solid-liquid phase change type ink, and there is a problem in the storage stability of the printed matter.

In view of this, an ink having a good coloring property with respect to plain paper, bleeding even when two or more colors of ink are ejected, feathering does not occur, excellent fixing properties, and a light load on the apparatus structure, and The recording method is disclosed in JP-A-7-258590. This ink and the recording method use an ink which is a homogeneous dissolution system at 25 ° C. and in which a compound having a thermoreversible gelling property is precipitated and dispersed in a temperature range between 30 ° C. and 65 ° C., On the other hand, it is characterized in that recording is performed while heating and holding the recording medium at a temperature above the temperature at which the ink is in a dispersed state.

Further, in the registered patent 3,064,318, it is possible to perform high-density and high-gloss printing without printing or image bleeding on any transfer target in a printing apparatus for recording an image with liquid ink. For the purpose of providing a printing method described in 1., a liquid ink, characterized in that a first liquid and a second liquid containing at least a coloring component are mixed immediately after ejection to be solidified and fixed on a transfer target. Discloses a technique for recording an image.

According to these, it is possible to impart unprecedented quick drying property without bleeding to plain paper (uncoated paper such as copy paper), which has been a problem in the past, and it is excellent in fixing property. In addition, it is possible to obtain an effect that recording that is excellent in the storage stability of the ink and the water resistance of the printed matter, which does not cause clogging, and enables clear recording with high density.

[0010]

However, the conventional proposals as described above have the following problems. That is, in the above two patents, when the ink jet is used for proof, special paper has to be used. Although there is a strong demand for printing paper for color proofing applications, from the viewpoint of bleeding and fixing when an image is formed with water-based ink on printing paper for the purpose of receiving oil-based ink, and in terms of transportability due to cockling of paper, It was difficult with technology.

The present invention has been made in view of the above circumstances, and an object of the present invention is to fix an image without bleeding even on an actual printing paper to obtain an image having good color developability, and to prevent jamming due to cockling. An object of the present invention is to provide an inkjet ink, an inkjet recording method, and an inkjet recording apparatus that can suppress the formation of an image.

[0012]

The present invention has been achieved by the following constitutions.

1. What is claimed is: 1. An ink comprising a recording material, a liquid medium for dissolving or dispersing the same, and a compound capable of increasing the liquid viscosity in a temperature range of 30 to 70 [deg.] C., the viscosity of the ink being adhered onto a heated recording medium. An inkjet ink characterized by increasing.

2. An ink obtained by mixing a first liquid containing a recording agent and a liquid medium for dissolving or dispersing the same and a second liquid containing a compound capable of increasing the liquid viscosity in a temperature range of 30 to 70 ° C. An ink jet ink characterized in that the viscosity of the ink increases when it adheres to a heated recording medium.

3. The temperature of the heated recording medium is 30
The inkjet ink according to 1 or 2, which has a temperature range of between 70 ° C and 70 ° C.

An ink jet recording method comprising the steps of recording an image on an intermediate transfer medium heated and held using the ink jet ink of 4.1, and then retransferring the image to a final recording medium.

An ink-jet recording method comprising using the ink-jet ink of 5.2 to record an image on an intermediate transfer medium heated and held, and then re-transferring the image to a final recording medium.

6. 6. The ink jet recording method according to 4 or 5, wherein the temperature of the intermediate transfer medium heated and held is in the range of 30 to 70 ° C.

7. An ink jet recording apparatus comprising a recording unit having an ink containing section containing ink and a head section for ejecting the ink as ink droplets, wherein at least a recording agent as ink, a liquid medium for dissolving or dispersing the same, A means for recording an image on an intermediate transfer medium heated and held using an ink liquid containing a non-film forming latex and a thickening resin, and means for retransferring the image on the intermediate transfer medium to a final recording medium. An inkjet recording apparatus characterized by the above.

8. An ink jet recording apparatus comprising a recording unit having an ink containing portion containing ink and a head portion for ejecting the ink as ink droplets, the ink containing a recording agent and a liquid medium for dissolving or dispersing the same. A means for recording an image by adhering the first liquid and a second liquid containing at least a non-film forming latex and a thickening resin onto an intermediate transfer medium heated and held, and an image on the intermediate transfer medium. And a means for retransferring the same to a final recording medium.

By adopting the above-mentioned constitution, bleeding and flow can be prevented regardless of the paper quality and the ink of the base, and the dots can be made uniform to obtain a high quality color image.

The present invention will be described in detail below. (Ink of Claim 1) In carrying out the present invention, a compound capable of increasing the liquid viscosity in the temperature range of 30 to 70 ° C (liquid viscosity increasing compound) described below exerts an essential action. Will be described.

Examples of the compound for increasing the liquid viscosity in the present invention include, for example, Polymers Collection, Vol. 38, p133 (1
981) and water-soluble cellulose ethers.

The characteristics of these water-soluble cellulose ether aqueous solutions are that the temperature coefficient of the solubility of the water-soluble cellulose ether is negative, so that the polymer microgel reversibly separates from the aqueous phase as the temperature rises and falls. It is to repeat dissolution in the aqueous phase. When the separation of this microgel from the aqueous phase occurs, the viscosity of the aqueous solution drops sharply. That is, the molecules are hydrated in a low temperature solution, there is no interaction between polymers other than simple entanglement, and a dehydration process occurs in which the polymer releases hydrated water as the temperature rises, resulting in changes in the physical properties of the solution. A decrease in viscosity occurs. Depending on the type of the liquid viscosity increasing compound, when the solution is cooled, the viscosity change process may have hysteresis. Although the details of the action when these substances are applied to the present invention are not clear, it is considered to be due to the action of simultaneously incorporating the recording agent when these substances are separated from the aqueous phase.

The above-described action of the liquid viscosity increasing compound in the ink will be described in more detail. In the separation of the solid content from the aqueous phase, the solvent component quickly penetrates into the recording medium after the ink has landed on the paper. It contributes to high-speed fixability. At the same time, a large floc of the recording agent is formed by the agglomeration action of the liquid viscosity increasing compound, and the effect of suppressing the permeation rate of the recording agent such as dye occurs, and the color material near the surface of the paper without the ink penetrating too deeply into the paper The remaining color development is not impaired. Further, not only the permeation of the ink in the depth direction is suppressed, but also the lateral spread is suppressed at the same time, so that the printing quality such as feathering and thickening of characters does not deteriorate,
Sharp edge printing is achieved. For the same reason, even when a full-color image is formed, it is possible to suppress bleeding (bleeding) due to color mixing of color inks, and it is possible to perform color inkjet recording with good fixability.

When ink jet recording is carried out using the ink of the present invention, not only is the intermediate transfer medium (recording medium) such as paper described above heated, but the temperature of the recording head is set above the temperature at which the ink is dispersed. It is also possible to cause the dispersed ink droplets to fly so that solid-liquid separation on the recording medium occurs more efficiently.

The present invention will be described in more detail with reference to the preferred embodiments. Examples of the liquid viscosity increasing compound used in the present invention include water-soluble cellulose ethers such as hydroxypropylcellulose, hydroxypropylmethylcellulose, methylcellulose, hydroxybutoxyl-modified methylcellulose / hydroxypropylmethylcellulose, and water-soluble polyvinyl acetals. It is not limited to these.

The molecular weight of the above compound is 25% of a 2% aqueous solution.
When converted to a viscosity at ° C, preferably 5 to 10,000 m
Pa · s is suitable. If the molecular weight is extremely large, it is difficult to precisely control the particle size of the gelled and agglomerated particles.

The above liquid viscosity increasing compounds can be used alone or as a mixture. The content in the ink varies depending on the dye or pigment used, the type of other additives and the solvent, and the like, but is 0.01 to 0.01% by mass in the ink.
It is 20% by mass, preferably 0.05 to 10% by mass, and more preferably 0.1 to 5% by mass.

In the ink used in the present invention, a surfactant or a penetrating solvent is used as a component which is more effective when used in combination with the above-mentioned liquid viscosity increasing compound. These are used for the purpose of improving the fixability of the ink.

There is no particular limitation on the chemical structure of the surfactant used in the present invention, and the water-soluble surface tension in CMC (critical micelle concentration) is preferably 1 × 10 ^-1 N / m to 4.
It is preferably × 10 ^-1 N / m. The content of the above-mentioned surfactant in the ink is 0.02 to 10% by mass, but it is within a suitable range in order to balance the fixability and the color developability.

The penetrating solvent used in the present invention includes monohydric alcohols such as ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, isobutyl alcohol, pentanol, cyclohexanol, benzyl alcohol, polyhydric alcohols and the like. It is an alkyl ether or the like. Specific examples thereof include 1,7-heptanediol, tripropylene glycol, hexylene glycol, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, and triethylene glycol monobutyl ether, but are not limited thereto. Even if a large amount of the above penetrating solvent is used, as described above, the shape of the single dot itself does not collapse due to the action of the liquid viscosity increasing compound, and a printed material with a sharp edge can be obtained.

The ink used in the present invention is characterized by containing at least the above-mentioned liquid viscosity increasing compound and a liquid medium for dissolving or dispersing the recording agent together with the recording agent. In addition to the agent, various dispersants, viscosity modifiers, surface tension modifiers, optical brighteners, antioxidants, fungicides, pH modifiers and other additives are included.

Recording agents usable in the ink include direct dyes, acid dyes, food dyes, basic dyes, reactive dyes,
Disperse dye, vat dye, soluble vat dye, reactive disperse dye,
Examples include oily dyes and pigments.

The content of these recording agents is determined depending on the type of liquid medium component, the characteristics required for the ink, etc., but generally 0.2 to 20% by mass relative to the total mass of the ink, Preferably 0.5 to 10% by mass, more preferably 1
˜5% by mass.

The liquid medium usable in the present invention includes methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol, and se.
c-butyl alcohol, tert-butyl alcohol,
Isobutyl alcohol, pentanol, alcohols such as cyclohexanol, dimethylformamide, amides such as dimethylacetamide, acetone, ketones or keto alcohols such as diacetone alcohol, tetrahydrofuran, ethers such as dioxane, diethylene glycol, triethylene glycol, Alkylene glycols such as tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol addition polymers, ethylene glycol, propylene glycol, trimethylene glycol, butylene glycol, 1,2,6-hexanetriol, and hexylene glycol, thiol Diglycol, glycerin, ethylene glycol monomethyl (or ethyl) ether, diethylene glycol monomethyl Or ethyl) ether, polyhydric alcohols such as triethylene glycol monomethyl (or ethyl) ether, lower alkyl ethers, polyhydric alcohols such as triethylene glycol dimethyl (or dimethyl) ether, tetraethylene glycol dimethyl (or diethyl) ether Lower dialkyl ethers, sulfolane, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone and the like can be mentioned.

The content of the above liquid medium is generally in the range of 1 to 50%, preferably 2 to 30% based on the total mass of the ink.

The above liquid medium may be used alone or as a mixture, but the most preferable liquid medium composition comprises water and at least one organic solvent, and the solvent is at least one water-soluble high-boiling solvent such as diethylene glycol. , A polyhydric alcohol such as triethylene glycol or glycerin.

In the present invention, various salts may be added for the purpose of adjusting the temperature at which the liquid viscosity increasing compound undergoes phase separation and solid-liquid separation occurs. As a method of knowing the temperature at which the above-mentioned phase separation occurs and solid-liquid separation occurs, the cloud point may be visually determined while gradually increasing the temperature of the ink, or the change in light transmittance using a spectroscope. You may ask from When more accurate measurement is required, the conventionally known method of measuring the cloud point of a surfactant by an optical method can be applied as it is.

The ink used in the present invention can be suitably applied to general ink jet recording systems in general, but is particularly preferable when it is applied to ink jet recording of a type in which ink is ejected due to the bubbling phenomenon of ink due to thermal energy. .

In the present invention, ink jet recording is carried out using the above-mentioned ink, and at the same time, the temperature of the recording medium (in some cases, intermediate transfer medium) is heated and maintained at a temperature at which the ink is in a dispersed state and solid-liquid separation occurs. Must have been done. The temperature of the recording medium refers to the surface temperature of the recording medium on which the minimum inkjet recording is performed.

To keep the recording medium heated above the temperature at which the ink is dispersed and solid-liquid separation occurs, (1) FIG.
(A), the infrared heater 9 and the blower fan 10 are arranged on the upper surface or the lower surface of the conveyance path of the recording medium and heated by radiant heat. (2) As shown in FIG. 1 (b),
The sheet heating element 11 is placed in the transport path and directly heated,
(3) As shown in FIG. 1 (c), it is possible to incorporate a heater in the paper feed roller (2a or 2b) and heat the paper from below with heat conduction.
Further, in the present invention, as described above, the temperature of the recording head may be heated and maintained at a temperature higher than the temperature at which the ink is dispersed for the purpose of more efficiently causing solid-liquid separation of the ink on the recording medium. In this case, when adjusting the physical properties of the ink of the present invention during non-operation and during operation (at the time of ejection), the main object of the present invention is the printability on plain paper and matching (ejection at the ejection head) to be used. Characteristics, reliability, etc.) are also preferably taken into consideration.

The temperature at which the ink is in a dispersed state can be adjusted by the kind, the molecular weight, and the addition amount of the polymer having the reversible thermogel property to be used. It can also be adjusted by the solvent used and the amount of solvent, or addition of an appropriate inorganic salt.

The preferred physical properties of the ink during operation are that the viscosity is 0.
5 to 5 mPa · s, more preferably 0.5 to 3 mPa · s
s, surface tension is 1 × 10 ⁻¹ N / m to 6.8 × 10 ⁻¹ N / m
m range, more preferably 1 × 10 ⁻¹ N / m to 4 × 10
It is preferably in the range of ^-1 N / m. (Ink of Claim 2) The ink is a recording medium and a first liquid containing a liquid medium that dissolves or disperses the recording medium, and 30
It is characterized by being mixed with a second liquid containing a compound capable of increasing the liquid viscosity in the temperature range of up to 70 ° C., which will be described in detail below.

The first liquid used here contains a coloring component as a recording agent. Examples of the coloring component include water-soluble dyes, oil-soluble dyes and dye solutions using organic and inorganic pigments, pigment solutions, aqueous emulsion inks, non-aqueous emulsion inks, inks in which these colorants are microencapsulated, resins as the coloring components. Colorant-containing resin emulsion having functional groups (amino group, carboxyl group, hydroxyl group, epoxide group, etc.) introduced on the surface, aqueous surfactant solution (anion,
Cations, nonions) and the like can be used.

When the amount of the dye / pigment added is less than 0.5% by mass, sufficient color tone / concentration cannot be obtained, and when it exceeds 10% by mass, clogging tends to occur.
0 mass% is preferable.

The resin emulsion containing a colorant may be a general emulsion, a self-crosslinking / crosslinking type reactive emulsion, or a latex polymer by copolymerizing an unsaturated acid monomer such as acrylic acid or methacrylic acid. An alkali thickening emulsion or the like that is provided by carboxylation is used. The alkali thickening utilizes the property that latex particles swell due to addition of alkali and the particle surface is dissolved to increase the viscosity. Further, as the microencapsulated ink, one obtained by forming and fixing a colorant around the resin emulsion or impregnating the resin with the colorant is used.

As the liquid viscosity increasing compound of the second liquid,
In addition to the above water-soluble cellulose ethers and water-soluble polyvinyl acetals, proteins (casein, glue, gelatin, gluten, soybeans, proteins), alginates (ammonium alginate, potassium alginate, sodium alginate), other vegetable thickeners (Arabic gum, tragacanth gum, karaya gum, guar gum, locust bean gum, Irish moss, soy lecithin, pectic acid, agar), mineral thickener (pentonite clay),
Acrylic acid thickener (ammonium polyacrylate, sodium polyacrylate, polymethacryl ammonium), polyvinyl alcohol, potassium salt of vinyl polymer, vinylpyrrolidone copolymer, polyacrylamide, polyethylene oxide, fibrin derivative (carboxylated methylcellulose, Methylcellulose), oleic acid, ammonium oleate, sodium silicate, a cationic activator (cetyltrimethylammonium bromide, cetylpyridinium bromide), etc., which is a solution containing resin emulsion particle surfaces in the first solution,
Adsorbed by the association of dye molecules (ion / micelle) 3
Those that form a three-dimensional network structure and thicken can be used.

When a liquid containing an electrolyte is added, the properties such as aggregation and salting out of dye can be utilized due to the decrease in interfacial potential and compression of the diffusion double layer. Further, a coagulant (formic acid, acetic acid, calcium nitrate, calcium chloride, acetic acid salt of cyclohexylamine, etc.) can be used.
Further, as the gelling agent, sodium fluorosilicate, potassium fluorosilicate or the like can be used. Also, acid (glycine, etc.), formalin, ammonium salt, etc. may be used as a destabilizing agent by decreasing the charge of the latex particles by lowering the pH, or a polyvalent metal salt or positive salt that reduces the charge of the latex particles. A water-soluble organic solvent that reduces the hydrated layer of polymer particles, a heat-sensitive coagulant (polyvinyl alcohol), such as the use of ionic surfactants, zinc-ammonium complex ions that modify the adsorption protection layer of polymer particles, trypsin, etc. (Methyl ether, polypropylene glycol, ammonium chloride, ammonium acetate, etc.), a metal oxide that cross-links with the first liquid, a cross-linking agent such as urea resin, epoxy resin, melamine resin, urethane resin, etc. can be used. .

First liquid for achieving the present invention, second liquid
The viscosity of the liquid is 50 mPa · s at 20 ° C.
If it is larger than s, clogging occurs and a problem occurs in ejection stability, so 50 mPa · s or less is preferable.

As a flying method, the second liquid is sprayed on the entire surface of the transfer object in advance and completely dried, and then the first liquid is allowed to fly, or two flying means are used. Liquid and the second liquid are sequentially ejected to be adhered to the transfer target in order, or the first liquid and the second liquid are ejected and then mixed during the flight, and the transfer is performed in the mixed state. There is a method of attaching it to the body.

The basic structure of the present invention is as described above.
In addition, conventionally known dispersants, surfactants, viscosity modifiers,
A surface tension adjusting agent, a specific resistance adjusting agent, a pH adjusting agent, an antifungal agent and the like can be added to the first liquid and the second liquid as needed.

Next, the ink jet recording method and the ink jet recording apparatus will be described in detail. An ink jet recording apparatus of the present invention includes an ink containing portion containing the above-mentioned ink and other components, and a recording unit having a head portion for ejecting the ink or the like as an ink droplet, and an image is formed on an intermediate transfer medium heated and held. And a means for retransferring the image on the intermediate transfer medium to the final recording medium.

In this ink jet recording apparatus, an ink liquid containing at least a recording agent, a liquid medium for dissolving or dispersing the recording agent, a non-film forming latex and a thickening resin is used as the ink. In another aspect, a first liquid containing a recording material and a liquid medium for dissolving or dispersing the recording material, and a second liquid containing at least a non-film-forming latex and a thickening resin are also used as the ink.

Examples of the non-film forming latex used here include low molecular weight polyethylene emulsions and tackifiers, and examples of the thickening resin include acrylic resins, vinyl acetate resins, styrene-butadiene resins, and chlorides. Vinyl resin, acrylic-styrene resin, butadiene resin, styrene resin, cross-linked acrylic resin,
Examples thereof include cross-linked styrene resins, benzoguanamine resins, phenol resins, and the above-mentioned liquid viscosity increasing compounds (cellulosic resins) which are heat gelling compounds.

FIG. 2 shows a sectional view of one mode of the recording means in the ink jet recording apparatus of the present invention. This recording apparatus expresses full color by using four color inks. The ink consists of four colors of ink, black, yellow, magenta, and cyan, respectively.

First, FIG. 2A will be described. An inkjet recording head 22 is mounted on a carriage device that moves in the axial direction of the platen at a position facing the platen 21, and pressing rollers 23 and 24 are in contact with the platen 21, and the intermediate transfer medium 25 is held by the platen 21. Along with. The platen 21 is made by laminating a silicone rubber or the like as a surface layer on the periphery of an aluminum tube and is rotated by a driving device (not shown). The recording head 22 is an inkjet recording head of a type that uses a piezoelectric element, and has color ink nozzles of 32 nozzles per color for four colors of yellow, magenta, cyan, and black, each of which has an arbitrary matrix. It is arranged. Then, each of the nozzles ejects ink by an electric signal from a head driving device (not shown) based on print data given to a computing device (not shown). It should be noted that the ink is supplied from the ink container 221 in which four colors of ink are filled in different rooms.

The pressing roller 23 is a rubber roller made of acrylonitrile rubber on a steel core material, and is a platen 2
It is in contact with 1 and is driven by the rotation of the platen 21. The pressing roller 24 is a roller in which nylon threads are planted on a steel core material, and it comes into contact with the platen 21 lightly and rotates at a speed slightly higher than that of the platen 21.

Next, the operation will be described. At the start of the printing operation, the intermediate transfer medium 25 is fed between the platen 21 and the pressing roller 23 by a paper feeding device (not shown), and the platen 21 and the pressing roller 24 rotate by a predetermined amount, so that the intermediate transfer medium 25 is recorded on the recording head. 22 and the intermediate transfer medium 25 on the platen 2
Adhere to 1. The recording head 22 supplied with the ink from the ink container 221 selectively ejects ink droplets from its nozzle according to the movement of the carriage and the printing pattern, and writes an ink image on the intermediate transfer medium 25. At that time, since each ink droplet separates the colored resin particles and the solvent on the recording medium and fixes the colored resin particles, the time difference until the next dot is overlapped is at least 2 seconds, The carriage movement, ink ejection frequency, and nozzle arrangement are adjusted. By repeating a predetermined amount of rotation of the platen 21 and the pressing roller 24 and printing by moving the carriage, after printing on the entire recording paper, the recording paper is discharged to a paper discharge tray (not shown) and the printing ends.

Next, FIG. 2B will be described. Figure 2
In the case of (b), it is possible to heat the intermediate transfer medium 25 at the time of writing an image to increase the separation speed of the colored resin particles and the solvent. A heater 26 is disposed inside the platen 21, and the platen 21 is heated by a temperature sensing means (not shown) and a heater control means (not shown) so that the surface temperature becomes a temperature at which the separation speed of the colored resin particles in the ink and the solvent can be increased. Have control over. Here, the temperature of the platen 21 is controlled to be 30 to 70 ° C. Further, in this recording method, the carriage movement speed is 510 mm / sec and the ink ejection frequency is 12 when the platen temperature is 30 to 70 ° C.
If the frequency is set to kHz, the time difference until the next dot is overlapped is 2
Although the example that is the second is shown, it is not limited to this,
Writing at higher speeds at higher temperatures is possible and various other combinations are possible. Also, the permeability of the solvent in the ink is affected by the ink components,
If the ink components are changed, it is necessary to change the combination of temperature and speed. A preferable platen temperature is preferably 50 ° C. to 100 ° C., more preferably 50 ° C. to 70 ° C., in order to secure a sufficient writing speed and prevent excessive energy consumption.
Is preferred.

Next, FIG. 2C will be described. Figure 2
The feature (c) is characterized in that the recorded image obtained by the above method is thermally fixed by another heating means 27. In this apparatus, the heating means 27 is composed of a metal roll having good thermal conductivity. The metal roll is provided with a heater 26 therein, and is heated by a temperature sensing means (not shown) and a heater control means (not shown) so that the surface temperature of the ink is equal to that of the ink. It is controlled so that the fusion temperature of the colored resin particles is + 50 ° C. Further, here, the temperature of the roll surface of the heating means 27 is controlled to be 120 ° C.

In order to prevent the colored resin particles on the intermediate transfer medium from transferring to the roll side, it is preferable to coat the metal roll surface with Teflon (R) resin, silicone resin or the like. Or, rotate the belt coated with the above resin,
A method in which the surface of the belt is brought into contact with the intermediate transfer medium and contact heating is performed from above with a heating roll is also effective. As another heating means, as shown in FIG. 2D, the intermediate transfer medium on which the ink image is written is heated in a non-contact manner by radiant heat from a heating means 28 including a heater and a reflecting mirror. You may.

Next, an image forming apparatus using the intermediate transfer medium will be described. As an image forming apparatus, for example, one shown in FIG. 3 is known. FIG. 3 is a schematic diagram schematically showing the main configuration of the image forming apparatus of the present invention.

The image forming apparatus 30 forms a color image with four colors of hot-melt ink (hot melt ink) of yellow, magenta, cyan and black. The image forming apparatus 30 is provided with a drive roller 31 driven by a motor (not shown) and a tension roller 32 facing the drive roller 31 at a constant interval, and the drive roller 31 and the tension roller 32 are surrounded by the drive roller 31. The endless intermediate transfer medium 33 is wound around. Below the right side of the intermediate transfer medium 33, a paper heater 34 is provided for guiding the recording paper P which is the final recording medium and heating it.

An ink jet head 35 is provided at an upper portion of the intermediate transfer medium 33 and at a position facing the intermediate transfer medium 33. The inkjet head 35 is a yellow head 3 that ejects yellow ink.
5a and magenta head 35 for ejecting magenta ink
b, a cyan head 35c that ejects cyan ink,
A black head 35d for ejecting black ink, and their nozzle surfaces are arranged side by side so as to face the outer peripheral surface of the upper portion of the intermediate transfer medium 33. or,
Each of the heads 35a to 35d is a so-called line head having nozzles arranged in the width direction of the intermediate transfer medium 33, and heated molten ink ejected from each of the heads 35a to 35d is superposed on the intermediate transfer medium 33. A color image is formed on the intermediate transfer medium 33. The intermediate transfer medium 3 is provided on the inner peripheral surface side of the upper portion of the intermediate transfer medium 33.
A guide plate 36 for guiding 3 is provided.
Further, a pressure roller 37 is provided so as to face the outer peripheral surface of the lower portion of the intermediate transfer medium 33, and a heat roller is provided at the inner peripheral surface side of the intermediate transfer medium 33 so as to face the pressure roller 37. 38 are provided. On the left side of the pressure roller 37, a peeling pawl 39 for peeling off the recording paper P attached to the outer peripheral surface of the intermediate transfer medium 33 is provided.

Further, on the upstream side of the tension roller 32 in the medium running direction, silicone oil 40 (coating agent) is applied to the outer peripheral surface of the intermediate transfer medium 33 in order to enhance the peelability of the heated and melted ink adhering to the intermediate transfer medium 33. A coating roller 41 for coating is rotatably provided. The coating roller 41 is partially immersed in the silicone oil 40 contained in the container 42, and at a timing for forming an image, the coating roller 41 is moved in a direction indicated by an arrow F1 by a moving mechanism (not shown), and the intermediate transfer medium 33 is formed. Contact the intermediate transfer medium 3
Silicone oil 40 is applied to the outer peripheral surface of 3.

When the image forming apparatus 30 as described above is started, the intermediate transfer medium 33 is rotated in the direction indicated by the arrow F2 by the rotation of the driving roller 31, and the coating roller 4 is also rotated.
1 moves in the direction indicated by the arrow F1, and the intermediate transfer medium 33
To the coating roller 4 on the outer peripheral surface of the intermediate transfer medium 33.
Silicone oil 40 is applied via 1. And
When the intermediate transfer medium 33 coated with the silicone oil 40 reaches the image formation start position, the inkjet head 3
5 is driven at a predetermined timing and each head 35a-3
The heated and melted ink is ejected onto the outer peripheral surface of the intermediate transfer medium 33 from 5d. As a result, a color image is formed on the silicon oil film of the intermediate transfer medium 33 by the heated and melted ink.

Subsequently, the heat roller 38, or FIG.
The means for heating and holding the intermediate transfer medium as described in 1. is arranged at a predetermined position with respect to the driving roller 31 to heat the intermediate transfer medium 33, and the surface temperature of the intermediate transfer medium 33 separates the colored resin particles from the solvent. The temperature is controlled so that the speed can be increased. Here, the temperature is controlled to be 30 to 70 ° C.

Then, the recording paper P is conveyed from the direction indicated by arrow F3 onto the paper heater 34 by a paper feed mechanism (not shown), and the recording paper P is heated by the paper heater 34 and conveyed toward the pressure roller 37. . The transfer start position on the recording paper P is controlled to be synchronized with the timing when the transfer start position reaches the pressure roller 37. The heat-melted ink on the intermediate transfer medium 33 is softened by the heating of the heat roller 38, and the recording paper P is pressed against the intermediate transfer medium 33 by the pressure roller 37 and the heat roller 38, and the softened heat-melted ink is recorded on the recording paper P. Transcribed on. And
The recording sheet P after the transfer is peeled off from the intermediate transfer medium 33 by the peeling pawl 39, conveyed in the direction indicated by the arrow F4, and ejected onto the tray by an ejection mechanism (not shown).

[0070]

The present invention will be described in detail below with reference to examples, but the embodiments of the present invention are not limited thereto.
In the following, all "%" are "mass%". (Preparation of ink liquid) Ink liquid 1 Aqueous dye (CI hood black) 2% Thermal gelling compound (Metroses SH Shin-Etsu Chemical Co., Ltd.) 15% Tackifier (Estergum H Arakawa Chemical Co., Ltd.) 10% Ethylene glycol 24% Diethylene glycol 15% Glycerin 7% Surfactant (Surfynol 104E manufactured by Shin-Etsu Chemical Co., Ltd.) 1% Distilled water 26% Ink liquid 2 Pigment dispersion (Carbon black; Mogul L. Canolac) 15% Thermal gelling compound (Metroze SH) Shin-Etsu Chemical) 15% Tackifier (Ester Gum H Arakawa Chemical) 10% Ethylene glycol 24% Diethylene glycol 15% Glycerin 7% Surfactant (Surfynol 104E Shin-Etsu Chemical) 1% Distilled water 18% Ink liquid 3 ・ No. 1 liquid aqueous dye (C.I. 2% Ethylene glycol 29% Diethylene glycol 15% Glycerin 7% Surfactant (Surfynol 104E manufactured by Shin-Etsu Chemical) 1% Distilled water 46% ・ Second liquid thermal gelation compound (Metroze SH Shin-Etsu Chemical) 35% Pluscoat Z446 (mutual compatibility chemistry) 15% Distilled water 50% Ink liquid 4 (comparative example) Only the first liquid of ink liquid 3 Ink liquid 5 (comparative example) Pigment dispersion liquid (carbon black Product name: Mogul L. Canolac ) 15% Ethylene glycol 24% Diethylene glycol 15% Glycerin 7% Surfactant (Surfynol 104E manufactured by Shin-Etsu Chemical) 1% Distilled water 38% (inkjet recording) Ink is ejected by a piezo oscillator using each of the above ink liquids. Commercial on-demand inkjet printer -Device (recording head ejection orifice diameter 50μm, piezo vibrator drive voltage 50V,
Charged ink mist method using ultrasonic atomization from a prototype multi-head (frequency 5 kHz)
High-speed recording was performed at Hz and a driving voltage of 50 V). The intermediate transfer medium was heated to 65 ° C. Then, the following evaluations were performed, and the results are shown in Table 1. (Evaluation) Bleeding of the edge portion of the image of 100% solid portion was evaluated according to the following criteria.

○: No bleeding △: Some bleeding is visually observable ×: Edges are considerably bleeding and the edges are jagged · Quick drying 3 seconds, 6 seconds, and 12 seconds after printing The edge portion was rubbed with paper and evaluated according to the following criteria.

○: no rubbing after 3 seconds Δ: rubbing after 6 seconds × ... rubbing after 12 seconds ・ Fixability The printed portion was rubbed strongly with a finger after 2 hours, and the situation was confirmed. The evaluation was performed according to the following criteria.

[0073] ○: The print part cannot be removed × ・ ・ ・ Printing part can be removed

[0074]

[Table 1]

As is clear from Table 1, ink liquids 1-3
It can be seen that the excellent effects are obtained in any of the evaluations of bleeding, quick drying property and fixing property. However, it can be seen that good results cannot be obtained in any of the evaluations for images recorded by ink jet recording using the inks 4 and 5 different from the present invention.

[0076]

EFFECTS OF THE INVENTION According to the present invention, it is possible to fix an image without bleeding even on an actual printing paper, to obtain an image with good color developability, and to form an image without jamming due to cockling. It has an excellent effect.

[Brief description of drawings]

FIG. 1 is a schematic view showing the structure of a printer including heating means.

FIG. 2 is a cross-sectional view of one aspect of recording means in the inkjet recording apparatus of the present invention.

FIG. 3 is a schematic diagram schematically showing the main configuration of the image forming apparatus of the present invention.

[Explanation of symbols]

1 sheet 2a, 2b Heating roller 3a, 3b Transport rollers 3c, 3d discharge roller 4 Platen 5 carriage 6a 6a1 pressing part 7 Main scanning rail 8 pressure roller 22 recording head 25 Intermediate transfer medium 30 image forming apparatus 35 inkjet head 40 silicone oil

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2C056 EA05 EA13 FC01 FC02 FD02                       FD13 HA41 HA42 HA46                 2H086 BA01 BA02 BA53 BA55 BA59                 4J039 AB01 AB02 AB07 AD06 AD07                       AD09 AD12 AD23 AE03 AE04                       AE05 AE07 BA10 BA17 BA22                       BA23 BA29 BA30 BC05 BC07                       BC09 BC13 BC16 BC19 BC31                       BC33 BC36 BC37 BC50 BC51                       BC54 BC55 BE01 BE03 BE04                       BE05 BE06 BE07 BE08 BE12                       CA03 CA06 CA07 CA09 EA43                       EA47 GA05 GA24

Claims (8)

[Claims] 1. An ink containing a recording agent, a liquid medium for dissolving or dispersing the same, and a compound capable of increasing the liquid viscosity in a temperature range of 30 to 70 ° C., which is deposited on a heated recording medium. Then, the ink-jet ink characterized in that the viscosity of the ink increases. 2. A first liquid containing a recording medium and a liquid medium in which the recording medium is dissolved or dispersed, and a second liquid containing a compound capable of increasing the liquid viscosity in the temperature range of 30 to 70 ° C. An ink-jet ink comprising the following: the viscosity of the ink increases when it adheres to a heated recording medium. 3. The temperature of the heated recording medium is 30 to 30.
The inkjet ink according to claim 1 or 2, wherein the temperature is in the range of 70 ° C. 4. An ink jet recording method, which comprises using the ink jet ink according to claim 1 to record an image on an intermediate transfer medium heated and held, and then re-transferring the image onto a final recording medium. 5. An ink jet recording method comprising using the ink jet ink according to claim 2 to record an image on an intermediate transfer medium heated and held, and then retransferring the image to a final recording medium. 6. The ink jet recording method according to claim 4, wherein the temperature of the intermediate transfer medium heated and held is in the range of 30 to 70 ° C. 7. An ink jet recording apparatus comprising a recording unit having an ink containing portion containing ink and a head portion for ejecting the ink as ink droplets, wherein at least a recording agent as ink is dissolved or A means for recording an image on an intermediate transfer medium heated and held using an ink liquid containing a liquid medium to be dispersed, a non-film-forming latex and a thickening resin, and a retransfer of the image on the intermediate transfer medium to a final recording medium. An ink jet recording apparatus comprising: 8. An ink jet recording apparatus comprising a recording unit having an ink containing section containing ink and a head section for ejecting the ink as ink droplets, wherein a recording agent as ink and a dissolving or dispersing agent. A liquid containing a first liquid and a second liquid containing at least a non-film-forming latex and a thickening resin, and a means for adhering the image on an intermediate transfer medium heated and held to record an image,
An inkjet recording apparatus comprising: a unit for retransferring an image on the intermediate transfer medium to a final recording medium.